Table of contents

Aluminium metal matrix composites (AMMCs) are the fastest growing metal matrix composites (MMCs) for the applications in several fields i.e.; automobile, aerospace and structural. The properties of these composites depend upon the reinforcement and their fabrication methods. This study focused on the accumulation of the ceramic reinforcement, silicon nitride (Si₃N₄) to the aluminium (Al) matrix in different weight proportions. Further, the significant methods for developing these materials and their effect on the various properties of the Al-Si₃N₄ composites have also been reviewed. The microstructural properties indicate the more uniform distribution of the reinforcing particles within the matrix for these composites developed by powder metallurgy method. From the literature, it has been also concluded that the addition of the ceramic reinforcement with appropriate weight percentages enhances the mechanical and tribological properties of the composites.

We review the principles of formation, physical properties, and current or envisaged applications for a wide range of carbon allotropic forms. We discuss experimental and theoretical advances relating to staple zero-, one-, and two-dimensional carbon structures, such as fullerenes, carbon nanotubes, and graphene. In addition we emphasize research on emerging carbon allotropes (carbon nanoscrolls, funnels, etc) that result from combining or deforming allotropic forms with well-defined dimensionality. Such materials fall in-between clearly delineated dimensional categories and consequently exhibit unique characteristics that are promising for electronic, optical, and mechanical applications. We also consider other approaches to tuning properties of carbon-based materials, such as chemical functionalization, intentional introduction of structural disorder, and placement of guest atoms or molecules inside hollow structures. Finally, we discuss the properties of and experimental methods for studying zero-dimensional systems (paramagnetic nitrogen impurity atoms) in diamond matrix. The review emphasizes the interplay between the various material properties of carbon-based nanostructures and the designs for nanoscale devices that rely on synergistic combinations of these properties. For example, an electromechanical vibrator, a strain sensor, a nanodynamometer, and a nanoelectromechanical memory cell that we describe exploit both electronic and nanomechanical properties of low-dimensional carbon structures, a reed switch and a magnetic field sensor use magnetic and nanomechanical properties, a maser based on nitrogen-doped diamond uses thermal and optoelectronic properties, etc. All presented device concepts have been validated by calculations, and some have been implemented experimentally.

Biological sensors have been extensively investigated during the last few decades. Among the diverse facets of biosensing research, nanostructured metal oxides (NMOs) offer a plethora of potential benefits. In this article, we provide a thorough review on the sensor applications of NMOs such as glucose, cholesterol, urea, and uric acid. A detailed analysis of the literature is presented with organized tables elaborating the fundamental characteristics of sensors including the sensitivity, limit of detection, detection range, and stability parameters such as duration, relative standard deviation, and retention. Further analysis was provided through an innovative way of displaying the sensitivity and linear range of sensors in figures. As the unique properties of NMOs offer potential applications to various research fields, we believe this review is both timely and provides a comprehensive analysis of the current state of NMO applications.

A significant laser-induced piezooptical response in novel CdCl_0.5J _0.5 nanolayers is obtained under the influence of laser illumination. The maximal piezo-optic response is observed for off-diagonal piezooptical tensor components. The layered structure allowed to obtain the thin specimens of thickness up to 1 nm with mirror-like surfaces. The observed studies show huge dependence of the piezooptics on the nanolayer thickness and the photoinduced beam power density. The effect is completely reversible. This fact allows proposing a new type of nanomaterials, which have significant benefits with respect to the other types of piezooptical materials (i.e. a possibility to use them in the laser operated devices).

While the ZnO based ultraviolet (UV) photodetectors are generally restrained by the slow response and the weak photosensitivity, present work develops a facile method to fabricate flexible UV photodetectors with high device performance based on graphitic carbon nitride (g-C₃N₄) quantum dot/ZnO nanowire nanocomposites. The sensors are prepared by spin-coating method followed by annealing on flexible substrates, which exhibit remarkable responsivity of 355 mA W⁻¹ under UV irradiation, a 1000% improvement over ZnO nanowire sensors (35.4 mA W⁻¹). Both on/off ratio and photoresponse current are significantly improved by introducing g-C₃N₄ quantum dots compared with pure ZnO nanowire sensors. Current report provides a new choice for UV material system to efficiently improve sensor performance, and it could be easily scaled up for large scale applications.

The aim of the present study is to investigate the photocatalytic and anticancer activity of green synthesized silver nanoparticle (AgNPs) using leaf extract of Justicia adhatoda. Several techniques were used to confirm and characterize the synthesized AgNPs. The synthesis of nanoparticle was identified by the formation of dark brown color in the reaction mixture and SPR band noted at 425 nm. The obtained AgNPs were spherical in shape with its average sizes in the ranges of 12.0, 26.7 and 47.9 nm, respectively, it can be tuned by varying the concentration of AgNO₃ analyzed by High resolution Scanning Electron Microscope and Transmission Electron Microscope (HRSEM with EDAX and TEM). The formation and size distribution of obtained AgNPs were determined by Dynamic Light Scattering (DLS) method. The negative zeta potential values were observed, causing dispersion stability of synthesized AgNPs. Fourier transform infrared spectroscopy (FTIR) and Surface Enhanced Raman (SERS) analyzed the existence of alcohols, amides and etc, in the leaf extract which behave as capping and reducing agents for the synthesis. The Face Centered Cubic (FCC) nature of AgNPs was depicted by x-ray Diffraction analysis. The photocatalytic activity is established by size-dependent nature of AgNPs, using an organic dye (methylene blue) as a substrate. Besides, the AgNPs showed significant anticancer activity against Human lung cancer cell line (A549). From in-vitro investigation and dye degradation experimental studies confirmed that the synthesized AgNPs have potent photocatalytic as well as anticancer activity.

The global market demands for new disposable wireless sensors for food, clinical, tissue, and drug industries in the near future. Gelatin-based multi-layer films were successfully prepared using a room temperature solution casting method. Anticipating future developments, we have looked at the potential applications of cost-effective passive RFID tags in the detection of bacteria (here trypsin was used for biosensing tests) in body fluids, foods, medicines, and much more. This paper is concerned with the measurement of the dielectric constant of materials remotely by using the frequency shift of RFID tags, in the first step. In continue, we establish a setup along with a novel multi-layer structure of gelatin films determining whether there exists any bacterium in a biological fluid or not, by using a physical approach. For this, penetration of bacterium through gelatin multi-layer films causes the RFID tags to be exposed to the biological fluid changing the dielectric constant, detected as a frequency shift. Samples were characterized utilizing FTIR, XRD, TGA, FESEM, tensile, and VNA analyzes. Our proposed wireless biomimetic sensor is able to detect trypsin within a few minutes. The immediate application of our designed biosensor is for the elderly and infants diapers, but further applications in biomedicine, biomedical engineering, food industry, and things like that can be anticipated.

Practical utilization of room temperature multiferroic BiFeO₃ is intrinsically limited by the absence of ferromagnetism. In this backdrop, development of weak ferromagnetism in 20 nm-sized BiFeO₃ nanoparticles is very optimistic. The origin of ferromagnetism is curious and paradoxical from long-range-order perspective since average superexchange angle Fe–O–Fe of the nanoparticle is in antiferromagnetic configuration. In this work, we resolve this paradox by establishing the beneficial role of local disorder with x-ray absorption spectroscopy. We distinguish between the natures of (Bi, Fe)-sublattice disorder and establish their correlation that eventually leads to ferromagnetism. Our results reveal intrinsic large Bi positional disorder, which may be attributed to 6s² lone pair activity of Bi atom and which leads to greater susceptibility of Bi-sublattice to modification during size reduction. Thus, local (BiO₆, FeO₆) units are observed to undergo large distortion and rotation respectively. We demonstrate with calculations that FeO₆ rotation is geometric consequence of BiO₆ distortion. In the case of our BiFeO₃ nanoparticles, experimental BiO₆ disorder induces FeO₆ rotation that drives Fe–O–Fe into ferromagnetic configuration. These local ferromagnetic units give rise to weak magnetism. This structural route to magnetism in BiFeO₃ can be generalized to encourage A-site disorder controlled magnetism or any functional octahedral rotation in ABO₃ perovsites. The results additionally propagate the effectiveness of particle size-dependence in generating A-site strain rather than chemical doping or external pressure.

Ni, Sn dual doped ZnO nanostructures were prepared with Sn = 0% to 5% using sol-gel route. Phase transparency of the synthesized samples was validated by x-ray diffraction (XRD) studies. Secondary phase was noticed at Sn = 5% which contains impurity SnO₂ with orthorhombic structure at 2θ ∼ 38.1°. The diminishing crystallite size by Sn substitution authenticated the inclusion of Sn in the Zn–Ni–O lattice. The anisotropic changes observed in lattice parameters and volume ascribed to the lattice disorder produced with Sn-doping and the ionic mismatch among Zn²⁺ (0.074 nm) and Sn⁴⁺ (0.069 nm). The elevation in absorption and the reduction in band gap by Sn-doping signified that they are helpful for photocatalytic and opto-electronic applications. The enhanced green PL emission by Sn doping is discussed based on the defect states like oxygen vacancies.

Magnesium aluminate spinel powder was prepared by one-step carbon-bed sintering at 1400 °C for 4 h with light magnesium oxide as magnesia source, alumina/boehmite/alumina-sol as alumina source, respectively. The phase composition of synthesized powders was characterized by X^_ray diffraction, and the microstructure was depicted by field-emission scanning electron microscopy. The effects of alumina type and carbon black (CB) on the phase composition and morphology of synthesized powders were studied. The results show that the type of alumina source has remarkable influence on the morphology of spinel powder. The average particle sizes of the product with both alumina and boehmite as alumina source are about 1.5 μm. However, the shape of the former is cobblestone while that of the latter is regular rhombic plate. Additionally, the morphology of boehmite was preserved in its corresponding product, implying that the spinel grows by template mechanism. The average particle sizes of the product with alumina-sol as alumina source were about 0.6–2.1 μm, and it possesses a regular octahedral structure. CB can be distributed more uniformly in the powder when polyvinylpyrrolidone (PVP) solution was used as a dispersant. The uniformly dispersed CB could significantly decrease the grain size of the product when alumina-sol was used as alumina source, but it had little effect on the particle size of products with alumina or boehmite as alumina source.

Pure and Ce-doped Al₂O₃ nanoparticles (NPs) were synthesized in different cerium percentages of 1%, 2%, and 3% by cerium chloride and aluminum nitrate precursors in the presence of powerful reducing agent-NaBH₄ and CTAB stabilizers using sol-gel method. To examine the crystal, morphological, optical, and electronic properties, the XRD, FESEM, TEM, FTIR, UV-DRS, and PL analyses were used for the heated samples in 1000 °C for 4 h. The XRD analysis indicated that the pure sample has γ, δ and θ phases, and the structure remained unchanged when Ce impurity was increased. The EDS analysis showed that the percentage of Al element was 47.40 wt% in the pure sample and that it increased to 53.83 wt% for 1% doped sample increasing Al ions in tetrahedral and octahedral sites of alumina through increasing Ce impurities. The TEM results revealed the sphere-like particles with mean particle size of 26 nm in diameter at a 3% level of impurity. The FTIR result showed that an increase in AlO₄ adsorption peak in 821 cm⁻¹ compared to AlO₆ adsorption peak in 619 cm⁻¹ was due to the dominance of vibrating bonds of tetrahedral sites rather than octahedral sites in alumina. The optical UV-DRS analysis also demonstrated the redshift configuration in a sample by increasing Ce dopant and reducing energy bandgap from 4.10 to 3.26 eV for pure and 3% Ce-doped Al₂O₃ NPs, respectively. Finally, the photoluminescence (PL) results indicated that increasing Ce dopant reduced electron-hole recombination leading to an increase in photocatalytic activity.

In-depth understanding of mechanical behavior of silicon carbide (SiC) at nanoscale was of great importance for its widespread application. However, the exploration of the relationship between mechanical properties and deformation mechanism has been impeded due to the lack of in situ measurement technology. Here we comprehensively studied the mechanical behavior of single crystal α-SiC nanowires (NWs) via a micro-electro-mechanical-system (MEMS) based in situ transmission electron microscopy (TEM) tensile experiments. Young's modulus, fracture strength and elastic strain limit of α-SiC NWs with the diameter ranging from 48 nm to 182 nm were investigated. Combining the various existing results of SiC nanostructures, general trends were found that fracture strength and elastic strain limit increased with the decreasing of diameter, while Young's modulus kept constant. Besides, all of the α-SiC NWs were elastically deformed until brittle fracture during tensile tests. By the aid of the in situ observations of deformation processes and fracture morphologies, the mechanism of size-dependent fracture strength and elastic strain limit of single crystal α-SiC NWs were discussed. The present findings provided guidance for the development and application of advanced micro-/nano- electronic devices with the comprehensive usage of SiC NWs in the future.

The major challenge faced in biomedical field is the formation of biofilm on polymer devices like catheters. It is important to functionalize the biomedical devices with a bactericidal agent through an easy and safe process in order to protect them from bacterial attack. In this article, the new method of impregnation of silver nanoparticles (AgNPs) into polymer film was proposed and tested against bacterial cells. The different sizes of silver nanoparticles were embedded in polystyrene film using thermal annealing and soft molding technique. Silver films having different thickness were deposited on the highly polished machinable glass ceramic (MACOR) substrate using direct current (DC) sputtering and subjected to at 750 °C for 15 min. After the heat treatment, AgNPs were formed on MACOR sample. It was then characterized using field emission scanning electron microscope (FE-SEM). Image-J software was used to analysed shape, size and distribution of AgNPs. The spin coating method was adopted to coat polystyrene film on to MACOR substrate supported AgNPs and allow it to cure for 24 h. After curing, the polystyrene film was peeled off and finally, AgNPs got transferred to polystyrene film. The AgNPs embedded polystyrene film was analyzed using FE-SEM and atomic force microscopy (AFM). Spread plate (plate counting) method was used to evaluate the bacterial killing potential of modified polystyrene film against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. The modified polystyrene film shows effective antibacterial ability against both the types of bacteria compared to the plain polystyrene surface.

MFe₂O₄ (M: Fe, Zn, Ni and Sn) nanoparticles were prepared using single step hydrothermal method. Their structural, compositional and dielectric properties have been studied to investigate the effect of cations on spinel ferrites. XRD confirms the spinel structure of the samples with substitution of Zn, Ni and Sn in the lattice sites of Fe. FTIR spectra of all samples have characteristic υ₁ and υ₂ bands. SEM and EDS mapping show uniform distribution of cations throughout the samples. ZnFe₂O₄ and SnFe₂O₄ have higher ac conductivity and dielectric constant than that of Fe₃O₄ and NiFe₂O₄, which can be attributed to the different cationic distribution in the spinel structure.

Novel concepts for light management in solar cells are very promising to increase the energy conversion yield, but industrial implementation has been slow. The nanoscale light management techniques often use methods, such as lithography or extensive heating, which are not compatible with industrial requirements. In this work we demonstrate that the use of a gas aggregation nanoparticle source is very suitable to produce optical nanostructures which can enhance the light absorption in a-Si layers. The ultra-clean silver nanoparticles were deposited within a minute at room temperature and their size combined with dielectric environment resulted in increased optical absorption in the near infra-red, where there is room for optical improvement. A thorough transmission electron microscopy and atomic force microscopy analysis provides parameters which are useful for industrial applications. Finite difference time domain (FDTD) simulations confirmed that the experimental optical effects were indeed produced by the plasmonic effect of the silver nanoparticles. These results provide an understanding of how solar cells can benefit from plasmonic nanoparticles from a gas aggregation nanoparticle source.

A symmetric bi-carboxylic acid functionalized salen-type ligand was used as organic linker to prepare a Cu-based infinite coordination polymer. The analytical data demonstrated that the proposed structure contains one bi-carboxylic acid salen type ligand and two copper cations in each monomeric unit. One of the Cu²⁺ cations is coordinated by N₂O₂ site of salen ligand and the other one acts as node to connect metal-organic linkers to each other. The reasonable formation mechanism for coordination polymer formation proposed which shows the formation of nanoparticles from intertwined oligomer chains. The prepared coordination polymer was used as a good precursor to synthesis copper oxide nanoparticles with larger band gap relative to bulk CuO.

Lung cancer is one of the leading cancer killer in both men and women worldwide. Toxicity of anticancer drugs towards normal cells is one of the major concern impeding the effective chemotherapy. Artemether (ART), an anti-malarial agent, revealed cytotoxic effect on tumor cells by down-regulating the expression of matrix metalloproteinase (MMP)−9, hypoxia-inducible factor (HIF)−1a, VEGF and other related proteins. The present investigation demonstrates development of ART loaded solid lipid nanoparticles (ART-SLNs) for the treatment of lung cancer. A 2³ full factorial design was applied to optimize ART-SLNs systematically. Concentration of drug, surfactant concentration and homogenization cycles were selected as an independent variables, and % drug loading (%DL), % entrapment efficiency (%EE) and particle size were selected as dependent variables. The mean diameter of optimized ART-SLNs was found to be 419 ± 09 nm, with %EE of 78.66 ± 1.93%, and %DL of 9.17 ± 0.11%. The in vitro dissolution studies revealed sustained drug release profile, revealing best fit with Korsmeyer-Peppas model. Further, the in vitro lipolysis study confirmed that ART-SLNs stabilized using MPEG₂₀₀₀-DSPE, exhibited anti-lipolytic effect. The stability (accelerated) studies does not showed any significant change in characteristics of developed ART-SLNs.

Polycrystal lanthanum hexaboride (LaB₆) tip field emitter has been prepared using the electrochemical etching technique. The effects of oxygen plasma treatment on its morphology, structure and field emission properties are mainly discussed. The results reveal that the surface morphology of emitters did not change significantly after oxygen plasma treatment. The oxygen plasma treatment does not introduce any new phase into LaB₆ emitter, but eliminates surface contaminants, which lead to lower work function. The cathode treated by 2 min shows the best emission performance during the field emission measurement. It obtains 8.2 μA at 2000 V, especially exhibiting strong ability of anti oxygen ion bombardment.

To enable the use of hollow porous silica nanospheres (HPSNs) as drug delivery carriers, it is necessary to control their pore size according to the molecular weight of drugs encapsulated by HPSNs. Therefore, a method for the control of the number and size of pores distributed over shell structure of HPSNs was suggested in this study. Specifically, HPSNs were synthesized with different amounts of tetraethyl silicate (TES) and various pH conditions using polystyrene-methyl acrylic acid (PSA) latex particles as the templates, and the morphology of the obtained HPSNs, particularly, the number and size of the pores, and the shell thickness, was characterized by field emission scanning electron microscopy (FESEM). Additionally, the potential use of HPSNs as carriers for the delivery of the Glp-1 peptide drug was examined. Specifically, the internal storage of Glp-1 in HPSNs and the release of Glp-1 from HPSNs as a function of time were investigated. HPSNs had very high loading capacities for Glp-1 and a steady release of Glp-1 from HPSNs of approximately 10% was observed. These results indicate that HPSNs demonstrate great potential as materials for both protection of Glp-1 from external attack and its long-term release.

Single-atomic boron-silicon (B–Si) layers show promise for applications in the field of two dimensional (2D) electronic devices. Using density functional theory, we have estimated the charge density properties along the various directions in 2D B–Si compounds. We have found that the Young's modulus for B-doped silicene increases in two mutually perpendicular 'armchair' and 'zigzag' deformation directions. We show that the increase in Young's modulus occurs due to the electron density increase on the B–Si bond.

In this research, WS₂ nanoparticles were synthesized using hydrothermal method then added to aluminum matrix as reinforcement. Nanocomposites were fabricated by powder metallurgy processing followed by Spark Plasma Sintering (SPS) consolidation. Microstructural, mechanical, and tribological properties of nanocomposites were investigated using optical microscopy (OM), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), uniaxial compression test and ball on disc tribometer. Microscopic analyses confirm the formation of well homogenized Al-WS₂ nanocomposites. Mechanical evaluations indicate that, the increase in weight fraction of WS₂ nanoparticles, results in improvement of hardness and compressive strength of aluminum. Addition of WS₂ nanoparticles up to 16 wt% doubles the yield strength of nanocomposites. Tribological study showed that the friction coefficient was inversely related to WS₂ content. Probing the wear behavior of samples revealed more than 40% reduction in friction coefficient of nanocomposites compared to that of pure aluminum. Furthermore, the wear mechanism has changed from adhesive to adhesive-abrasive mechanism.

The present study deals with the vibration and buckling of functionally graded carbon-nanotube-reinforced composite (FG-CNTRC) annular plates subjected to thermal loading. Thermo-mechanical characteristics of the materials are temperature-dependent (TD). Based on Mindlin's plate theory and using Hamilton's principle, the governing equations are derived. The generalized differential quadrature (GDQ) approach and periodic differential operators are employed to numerically solve the problem. The proposed approach is verified through different comparative studies. Additionally, to study the impacts of involved factors on the instability and vibration characteristics of CNT-reinforced composites annular plates, a wide range of results is presented. The results reveal that considering the TD material properties considerably affect the mechanical characteristics of thermally-induced CNT-reinforced composite plates.

Hieratically self-assembled iron oxide nanosheets have directly been synthesized by a facile chemical co-precipitation method without any template at the presence of poly(ethylene glycol) (PEG) through the self-assemble behavior of PEG-coated iron oxide nanoparticles. These iron oxide nanosheets were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–vis spectroscopy (UV–vis), thermogravimetric analyzer (TGA), Zeta Potential and vibrating sample magnetometer (VSM). The results proved the nanosheet structure and the stability in broad concentration range of salt and at broad pH values. The application of these nanosheets in heavy metal removal has also been investigated. The results indicated that these iron oxide nanosheets could adsorb lead ions in aqueous solution even at neutral environment and show high adsorption capacity of 336 mg g⁻¹, which is higher than that of other reported adsorbents. The adsorption behavior well fitted Langmuir isotherm modal and followed pseudo-second-order kinetics. This research provided a platform for the application of self-assembled nanosheet structure in Pb²⁺ removal with high adsorption efficiencies compared with those traditional 2D and 3D materials that were complicated and energy cost in preparation.

In this work, NiCo₂O₄ nanoparticles were synthesized by solution combustion method and NiCo2O4/PANI composite was prepared by physical blending method. The samples were od. The samples were characterized by Fourier transform infrared spectroscopy, x-ray diffraction analysis (XRD), scanning electron microscope (SEM), high- resolution transmission electron microscope (HRTEM) and Electrochemical studies such as Cyclic voltammetry (CV) and galvanostatic charge—discharge analysis. XRD peaks revealed the crystallite size of the NiCo₂O₄ and NiCo₂O₄/PANI composites. The samples were refined using Rietveld refinement method. The values of crystallite size and strain determined by W-H method were in good agreement with the results obtained in the Scherer method. FTIR confirmed the presence of respective functional groups. Morphology was studied by SEM and HRTEM images. The Morphological changes in Composite implied the enhanced electrochemical activity. The crystalline nature of NiCo₂O₄ and NiCo₂O₄/PANI nanoparticles observed by XRD study was further confirmed by SAED pattern of HRTEM images. The specific capacitance of the samples were calculated by CV and CP in three electrode configuration. Specific capacitance obtained for NiCo₂O₄ in 5 mV s⁻¹ was 723 F g⁻¹ and for NiCo₂O₄/PANI was 882 F g⁻¹ from CV study. The maximum specific capacitance obtained for NiCo₂O₄ was 729 F g⁻¹ and for the composite NiCo₂O₄/PANI was 887 F g⁻¹ at the applied current density of 0.5 A g⁻¹ through galvanostatic charge—discharge analysis. NiCo₂O₄/PANI composites showed potential and high performance, in which the maximum specific capacitance was exhibited.

Functionalized Ag/ZnO core–shell (CS) nanoparticles (NPs) with ethylenediaminetetraacetic acid (EDTA) having same core size but with different shell thickness are successfully prepared through a simple and low cost wet chemical process. Different physiochemical characterizations including transmission electron microscopy, x-ray diffraction, Brunauer-Emment-Teller surface area analysis, zeta potential analysis, thermal gravimetric-differential analysis, UV-visible absorption spectroscopy, Photoluminescence Spectroscopy and Fourier-transform infrared Spectroscopy have been involved to characterize the samples. The thickness of ZnO shell of Ag/ZnO CS NPs is found to be increasing with increasing molar ratio of EDTA/Zn²⁺. The LSPR wavelength of Ag core is shifting to longer visible wavelength with increasing the shell thickness of Ag/ZnO CS NPs because of the increase in the dielectric constant of the sourrounding environment. The increasing shell thickness of Ag/ZnO CS NPs makes a strong effect on the decrease in the fluorescence intensity of UV emission of ZnO. This quenching of PL intensity has been further verified by transient fluorescence (FL) spectra. The Nyquist plots also provide evidence of higher electron-transfer rate of the Ag/ZnO CS NPs of having higher shell thickness. The photocurrent measurement confirms electron-charging of Ag core in Ag/ZnO CS NPs. Variation of concentration of EDTA as anionic surfactant causes variation of surface charge of Ag/ZnO CS NPs. With increasing the shell thickness, photodegradation efficiency of Ag/ZnO CS NPs towards methylene blue (MB) degradation enhances under sunlight irradiation. This enhancement in photocatalytic efficiency with increasing the shell thickness is achieved due to the higher surface area, higher charge transfer efficiency, extended light absorption towards visible region and more negative zeta potential of Ag/ZnO CS NPs.

CdS and CdS:Cu quantum dots are synthesized by chemical method using 3-mercaptopropionic acid (MPA) as capping material. The samples are then characterized using different structural and chemical characterization techniques which confirms nanoformation of the samples. The as-synthesized quantum dots are used to fabricate simple devices on glass substrate by depositing Aluminium (Al) electrodes on the active quantum dot layer with thermal evaporation technique. The current-voltage (I-V) relationship of the quantum dot devices are investigated under dark, room light and laser light (Red-638.2 nm) conditions and enhancement in photocurrent with increase in light intensity is observed for the devices.

The degradable polymer biomaterials have great potential in the field of nerve regeneration, which have gradually been applied to spinal cord injury repair. In this study, a polylactic acid-glycolic acid copolymer (PLGA) porous scaffold was prepared by the process of phase inversion, then the surface of the scaffold was modified by polydopamine (PDA) as a substrate, followed by adsorption of nerve growth factor (NGF) to obtain a PDA-PLGA/NGF scaffold. The characterization and hydrophilicity of the scaffolds were evaluated by electron microscopy, EDX and contact angle measurement. The effect of PDA modification on the binding efficiency and release profile of NGF was observed by ELISA. The proliferation and differentiation of NSCs on the surface of biomaterials was evaluated by MTT, immunofluorescence staining and PCR. Subsequently, the rat T9 spinal cord transection model was established and the nerve scaffolds were implanted to injured site. Our results showed PDA modification could significantly improve the NGF adsorption capacity and provide sustained release of NGF. PDA-PLGA/NGF scaffolds could not only enhance NSCs proliferation and neuronal differentiation in vitro, but also promote recovery of spinal cord injury in vivo. Therefore, we believed that PDA-PLGA/NGF scaffolds could be a promising method to facilitate neurogenesis and repair spinal cord injury.

The physical and optoelectronic properties of MoS₂ are closely related to their thickness. Few-layer molybdenum disulfide (MoS₂) has been intensively studied for its potential applications. In this work, monolayer and few-layer MoS₂ nanosheets with large size and high crystallization quality were successfully prepared by chemical vapor deposition (CVD) .Then, the layer number of CVD-grown MoS₂ nanosheets were identified for the first time by extracting the R channel contrast of the optical image of the sample with ImageJ software. Compared with Raman spectra and PL spectra, this method can identify the layer number of CVD-grown MoS₂ nanosheets efficiently and accurately, which provides a simple and feasible method for the study of the layer number of CVD-grown MoS₂ nanosheets and can help us exploiting their applications in the future.

Potassium dihydrogen phosphate (KDP) has been extensively used in electro-optic switches and laser spectroscopy in modulating the frequency of laser radiation. When making refined optical KDP components for such applications, the external stresses in the manufacturing process can introduce changes in their optical and electronic properties. With the aid of the ab initio density functional theory analysis, this paper investigates the effect of stresses on the absorption coefficient, band gap, refractive index, dielectric function and Plasmon energy. It was found that the stress-induced variations in these properties are due to a change of KDP molecular structures. The microstructural changes induced by the uniaxial (along the 〈110〉 direction) or by the biaxial (〈100〉 and 〈010〉 directions) or by the triaxial (〈100〉, 〈010〉 and 〈001〉 directions) tensile stresses bring about significant changes in the optical and electronic properties of KDP.

The relations between macroscopic and microscopic characteristics of materials are of utmost importance for synthesis of multi-atomic structures with advanced properties. We analyze the influence of pulse duration, pulse energy and temperature of liquid on the process of formation of nanoparticles (NPs) of the metals (In, Sn, Zn and W) with different hardness and melting temperature by laser ablation in liquid environment. Composition, morphology dynamics and properties of nanoparticle suspensions are studied using TEM analysis and Z-scan technique. The nonlinear optical properties of NPs are analyzed at 800 and 400 nm using 60 fs and 200 ps pulses. We show that pulse energy have little influence on the formation, morphology and size of NPs during ablation of low hardness and melting point metal (In). However, pulse duration plays a very important role during the formation of NPs, especially the ultra-short pulse has a positive effect on the preparation of NPs with smaller particle size. In addition, the temperature of liquid environment influences the formation of NPs and their nonlinear optical properties.

Two types of Al₂O₃/(W_0.5,Ti_0.5)C ceramic composites with and without metal phase Ni were studied in this research. The evolution mechanism of bending strength and fracture toughness at both ambient and high temperature(600 ∼ 1000 °C) was studied. The influence of nickel on mechanical behavior and microstructure of composites was also analyzed in the test temperature range. The results showed that the bending strength of both ceramic composites decreased with gradually increased temperature. The bending strength of Al₂O₃/(W_0.5,Ti_0.5)C/Ni was greater than that of Al₂O₃/(W_0.5,Ti_0.5)C ceramic composites at room temperature. However, the bending strength of Al₂O₃/(W_0.5,Ti_0.5)C/Ni decreased more rapidly at high temperature. The fracture toughness of Al₂O₃/(W_0.5,Ti_0.5)C/Ni was always greater than that of Al₂O₃/(W_0.5,Ti_0.5)C at different temperatures. The addition of metal phase had a positive impact on the fracture toughness at different temperatures. It was found that the matrix and the toughening phase were well combined by the metal phase, so the room temperature bending strength of Al₂O₃/(W_0.5,Ti_0.5)C/Ni was enhanced. However, the decrease of interfacial bonding strength caused by the low-melting metal phase led to the fracture mode changed. Moreover, the elastic modulus of Al₂O₃/(W_0.5,Ti_0.5)C/Ni decreased faster at elevated temperatures, which resulted in lower bending strength. The research on the evolution law of mechanical behavior of composites at elevated temperatures has important guiding significance for the design of materials and the choice of cutting parameters.

Iron oxides are considered a very interesting class of materials due to their morphological characteristics, especially in the adsorption and catalysis fields. As an adsorbent, iron oxide is used both in water and industrial wastewater treatment. In this paper, iron oxide samples were obtained in goethite and magnetite phases by acid method starting from the intermediate green rust II (GRII). For that, the molar [FeSO₄]/[NaOH] ratio was determined at R = 1.00. The influence of the oxygen flow rate introduced into the reaction mixture, the reaction temperature, stirring speed during mixing, and reaction time on the quality of the iron oxides produced were evaluated. It was possible to propose and validate a kinetic mechanism for iron oxide production based on the particle size/reaction time dependence. In addition, a limiting step for the reaction rate was also proposed.

SiC nanowire aerogel (SNA) with highly porous 3D nanowire architecture was synthesized by polymer pyrolysis chemical vapor deposition (PPCVD) process to deposit SiC nanowires in the pores of carbon foam, followed by high temperature oxidation of carbon foam. The microstructure of the prepared SNA was characterized by SEM, TEM and a large number of interweaving SiC nanowires with a diameter of 80–100 nm and a length of hundreds of micrometers form the highly porous 3D nanowire architecture of SNA. The prepared SNA possesses the performance combination of ultra-low density (30 ± 7 mg · cm⁻³), high-temperature oxidation resistance (750 °C), noncombustible and fire resistance property in the fire, excellent thermal insulating property (0.03 W · m⁻¹ · ^·k⁻¹ at room temperature in He) and compressive strength of 0.11 MPa, which is applicable as high-temperature heat insulator, ceramic matrix composite, high temperature flue gas filter, fire-proofing material and catalyst carrier.

Shock wave recovery experiment on crystalline materials is a hot research topic for aerospace applications. In this research article, authors present and demonstrate the stability of physical properties of ZnO nano rods (ZnO NRs) under shock wave loaded conditions. The test sample is synthesized by hydrothermal method and the shock waves were generated using a table top semi automatic pressure driven shock tube. A shock wave of 2.2 Mach number which has a transient pressure of 2.0 MPa and temperature 864 K was made to strike four test samples for the counts of 50,100,150 and 200, respectively. The shock loaded samples were subjected to XRD and optical analysis so as to understand the influence of shock waves in the structural and optical properties. The results show that ZnO NRs have magnificent molecular, optical, structural and morphological stability for 50,100 and 150 shocks. Though, when the number of shock pulses was increased to 200 and a blue shift was observed in UV–vis spectrum, no changes in structural properties took place which was evidenced from XRD. From this shock wave recovery experiment, it is clear that ZnO NRs are highly stable against shock waves and hence this material is suggested for the aerospace and military applications.

The silver nanoparticles (AgNPs) synthesized by physical and chemical methods are not much desirable due to the use of high energy consumption, environmentally toxic and biological hazards chemicals. Therefore green synthesis of AgNPs using natural plant extract is more appropriate method. Hence, in the present work we have employed an anti-cancer plant, which is used in Indian system of medicine Flacourtia indica to develop the AgNPs and also revealed their anticancer potential in Dalton Lymphoma Ascites (DLA) cell line model. Among the solvent extracts of F. indica, methanol extract was found to contain higher level of yield (5.14 g/100 g) and total phenolic compounds (9104 mg gallic acid equivalents/L) with good antioxidant power. Hence the preparation of methanolic extract from F. indica was optimized using Response Surface Methodology (RSM), which indicated that 88% of methanol concentration, 50 °C of temperature and 88 min of extraction time results in higher phenolic yield. The optimized F. indica extract strongly reduced the silver into AgNPs. The synthesized AgNPs were characterized using Ultraviolet-visible spectroscopy scanning (major peak at 455 nm), transmission electron microscopy (particle size of 14–24 nm) and zeta potential (−15 mV). The higher level of anti-proliferative activity (76.97%) was noted for AgNPs when compared to crude extract in DLA cell line model through cytotoxicity assay.

The world is facing challenges of energy shortage and it requires innovations in energy storage devices that needs be more efficient and economically viable. Addressing these issues, in the present work poly (1, 8-diaminonaphthalene/CdSe(S) nanocomposites were synthesized following an economic chemical oxidative polymerization method. The Fourier transform infrared (FTIR) spectra confirmed the presence of CdSe in the poly (1, 8-diaminonaphthalene) (PDAN) matrix. The crystallite size in PDAN/CdSe nanocomposites was calculated from x-ray diffraction (XRD) spectra and it was found to be of the order of 4 nm. The lattice constant was also calculated from XRD analysis and it was calculated to be 5 Å which agrees well with that of the CdSe. Field emission scanning electron microscope (FESEM) images showed homogenous dispersion of spherical particles in the host polymer matrix. It ensured the presence of PDAN and agglomerated CdSe quantum dots (QDs) in the PDAN matrix. Impedance data were analyzed by fitting an electrical equivalent circuit based on Randle's model. When PDAN was subjected to form nanocomposites with the CdSe, there was a decrease in the dielectric constant and an increase in the dielectric loss due to alignment of polarization charges with frequency. The results indicate that the mechanism of alignment of charge carriers with frequency could be helpful in increasing the charge storage capacity of the material. Thus due to low loss at lower and at higher frequencies in the nanocomposites, the nanocomposites of PDAN/CdSe have potential to be used at these frequencies in charge storage applications in electronic industry.

In this work, we have demonstrated the photoluminescence enhancement of metal alloy (NiTi and CuAl) coated ZnO nanorods. The ZnO nanorods were grown by the conventional hydrothermal process on which the alloy nanoparticles (NiTi/ CuAl) were dispersed through pulsed laser deposition technique. An enhancement in photoluminescence was observed because of metal alloy nanoparticles were dispersed on ZnO nanorods. The maximum achieved UV enhancement with a factor of ∼8 and defect suppression with a factor of ∼2.4 were observed for NiTi coated ZnO nanorods. However, CuAl coated ZnO nanorods showed relatively less enhancement (∼4.3) and improved suppression (∼4.1) compared to NiTi coated ZnO nanorods. Such emission enhancement and defect suppression can be attributed to the resonant coupling between electron-hole pair and carrier transfer between metal and ZnO nanorods. Hence, the metal-ZnO interface plays an important role towards the enhancement factors. Therefore, we can claim that the Earth-abundant metal alloy coated ZnO nanorods show comparable surface plasmon resonance effect in comparison to the noble metals coated ZnO nanostructures.

Hydrogen peroxide (H₂O₂) is one type of reactive oxygen species (ROS) that can lead to a variety of forms of oxidative stress damage in human beings. Numerous methods have been used to detect H₂O₂ concentrations in various environments, however, these often suffer from inadequate detection limits, instrumental complexity, and multi-step experimental design, which may render them unfeasible for the required application. Herein, we report on a novel method for H₂O₂ detection that utilizes thiol-based SiOx nanodots (S-SiOx NDs) to initiate a sol-gel phase transition which can be observed by naked eye. This approach could lead to a very simple, rapid, and low cost method for H₂O₂ detection down to 5.8 μM, which is lower than the FDA regulation for H₂O₂ in food packaging. Furthermore, using a PL spectrometer allows H₂O₂ detection down to 0.01 μM. This S-SiOx NP system allows researchers the flexibility to choose between rapid visible detection of H₂O₂, or very high sensitivity detection by PL spectrometry.

in this study, the mechanical properties and deformation mechanism of a niti alloy are investigated using in situ TEM compression, nanoindentation, and vickers hardness tests. the Young's modulus of a niti micropillar measured during an in situ TEM compression experiment was significantly smaller than that obtained by nanoindentation. the mechanical strength of the material is influenced by the annealing temperature. additionally, the size effect of the niti alloy pillared structures on compression and bending was affected by contamination with gallium ions. the mechanical properties, contact behavior, and local bending fracture results for niti alloy nanopillars and blocks are consistent with previous literature reports. these results provide potentially useful information concerning the mechanical properties, contact behavior, and local bending fractures of niti alloy nanopillars and blocks.

In this study, the fabrication of Al-Al₂O₃-TiB₂ hybrid composite using TiO₂, B₂O₃, and Al5083 powders through aluminothermy method has been studied. TiO₂, B₂O₃, and Al5083 powders were attrition milled (20:1 bullet to powder ratio, under argon atmosphere, the speed of 650 rpm for 2, 4, 6 and 20 h). After the completion of the milling process, the milled powder was added to the aluminum molten at 900 °C and finally, the Al5083-Al₂O₃-TiB₂ composite was produced in situ. After the hot extrusion process, specimens were characterized by SEM and XRD analyses and the strength of the composite was investigated. The results of the microstructure analysis and the strength of the specimens indicate the efficiency of low milling times and the absence of TiB₂ in milling. The observations from microstructure show presence of TiB₂ ceramic particles less than 300 nm in size. The strength tests done on 2, 4, 6 and 20-h specimens represent values of 294, 336, 295 and 276 MPa, respectively.

The present research work has focused to study the influence of base oil mixed with multi-wall carbon nanotubes (MWCNTs) nodular cast iron contacts with the steel to examine the tribological performance. The wear studies were carried out using a pin-on-disc tribometer. In this study, the percentage of oil concentration, the applied load carrying capacity, and the stability of lubrication film were investigated by varying two sets of sliding conditions. It was observed that the tribological behavior (friction, lubrication, and wear) was improved when the base oil mixed with MWCNTs when compared to the base oil alone. Further, the incorporated MWCNTs with the base oil was enhanced the load carrying capacity and the lubricating oil stability. The mechanisms behind the improvements of lubricating oil with MWCNTs on the nodular cast iron were also studied, investigated, and reported.

Copper doped indium oxide (In_2−xCu_xO₃) nanostructures were prepared by a simple citrate gel process using indium nitrate and copper nitrate as precursors. The influence of the dopant concentration (x = 0, 0.03, 0.05 and 0.07) on the structural, morphological and the electrical properties of indium oxide was studied. The crystallite size and the surface roughness (root mean square roughness and the mean roughness) of the prepared samples increased as a function of the dopant concentration. However, the copper (Cu) concentration did not affect the basic host crystal structure. The prepared samples showed an n-type semiconducting behavior and a variation in the electrical parameters, which might be due to the confinement of the electronic states of the dopants to small volumes (less than 100 nm). Implication of the degenerate electron gas model to the experimental electrical data revealed the role of the different scattering centers in conduction electron scattering.

Upconversion nanoparticles (UCNPs) have drawn much attention in the past decade due to their superior physicochemical features and great potential in biomedical. However, practical applications of upconversion luminescence are often limited by its relatively low luminescence efficiency. In this paper, we designed and synthesized NaYF₄:Yb, Er nanoparticles using a hydrothermal approach, and thereafter it was coated with a thin layer of graphitic carbon to form a core/shell nanostructure via a controlled chemical vapor deposition process. It is shown that Yb and Er doped in the crystal of NaYF₄ in the forms of Yb³⁺ and Er³⁺. The thickness of the graphitic carbon shell is close to 0.45 nm, and this corresponds between one and two atomic layers. The graphitic carbon shell not only leads to a significant enhancement in the emission intensity but also provide a longer luminescence decay lifetime compared to bare NaYF₄:Yb, Er nanoparticles. Our finding provides a new strategy to remarkably improve fluorescence upconversion, and opportunities for diverse applications requiring high fluorescence intense.

CsPbBr₃ perovskite nanocrystals (PNCs) have been synthesized using the hot injection method. The CsPbBr₃ PNCs exhibit a high photoluminescence quantum yield (PLQY) of 73%. A comprehensive study of UV light interaction with the CsPbBr₃ PNCs was performed. SEM images, photoluminescence spectra, x-ray Diffraction and PLQY measurements were obtained for different time of UV exposure. The exposure to UV light modifies the crystal size (from 10 × 10 nm to 12 × 95 nm) and morphology (change from nanocubic to nanorods form). The XRD spectra show a change from tetragonal to cubic crystalline structure. In addition, the interaction of UV light modifies the optical properties of the PNCs by varying the photoluminescence. The material remains stable for a period of 1 h, however, with exposure to UV light, the PNCs show a decrement in QY from 73.3% to 46.6% after 30 days. These results indicate that light-induce variation in morphological and photo-stability of CsPbBr₃ PNCs.

In this work, monodisperse spherical vaterite calcium carbonate (CaCO₃) was synthesized at room temperature and atmospheric pressure through a simple and efficient 'phase transfer-precipitation' route using phosphogypsum (PG) as raw material, sodium gluconate(SG) as phase transfer agent and CO₂ as precipitator. CaCO₃ samples were characterized by Field-emission scanning electron microscopy (FE-SEM), x-ray diffraction (XRD), and Dynamic light scattering (DLS). The composition of the as-obtained sample was almost monodisperse spherical vaterite CaCO₃ by adjusting the concentration of SG and other operational conditions. The effects of SG and STP on the formation of CaCO₃ microspheres were investigated. The results indicated that the existence of SG inhibited the nucleation and growth of calcite but promoted the formation of vaterite. The effects between SG and Ca²⁺ played a key role in the formation process of monodisperse spherical vaterite CaCO₃. The existence of STP can effectively control the further growth and enhance the uniformity of the particle size of CaCO₃ microspheres. These studies are promising for the industrial preparation and further commercial applications of monodisperse spherical vaterite CaCO₃.

Tin dioxide nanofibers were successfully synthesized by electrospinning homogeneous solution of SnCl₄·5H₂O in polyvinyl alcohol (PVA) and the potential of SnO₂ nanofibers as ammonia sensing element at room temperature were also investigated. A logarithmic dependence of sensitivity on ammonia concentration was observed. We further investigate the effect of relative humidity between 0% and 70% on ammonia sensing performance of SnO₂ nanofibers based conductometric sensor for the first time. Sensing experiments showed that both the baseline sensor current and the response-recovery characteristics of the SnO₂ based sensor modified by pre humidification of sensing layer' surface. To study the adsorption kinetics pseudo first order and Elovich models was used and the first order kinetic model best describes the ammonia adsorption onto the SnO₂ nanofibers for low concentrations (≤80 ppm) of ammonia, irrespective of humidity level. On the other hand, the results describe the best representation of Elovich model, as evidenced by the high correlation coefficients, for high concentrations of ammonia gas.

This work deals with stability, structural and electronic properties of perfect ZnO nanosheet and substiutionally doped ZnO nanosheet with Si are simulated and optimized successfully using density functional theory (DFT) with the help of SIESTA program in the generalized gradient approximation (GGA). The substitution atoms have been replaced on the oxygen site in line and zigzag doping. The stability of perfect ZnO nanosheet and ground state structures of Si_n-ZnO (n = 1–6) are studied in terms of binding energy, show that a maximum stabilized of one Si in line doping and two Si in zigzag doping due to the dopant located in the center of nanosheet is a more stable. The electronic properties of ZnO nanosheet and Si-doped are discussed using ionization potential, electron affinity, HOMO–LUMO gap, electronegativity, and hardness. The results showed the presence of silicon atoms substitution expands the bond length with respect to perfect ZnO nanosheets. The obtained values of HOMO and LUMO are slightly different and this suggests that different of position dopant play significant roles on electronic properties and large electron affinity at four silicon atoms doped ZnO nanosheet in two cases that it improved the electron more accepting ability. The study of HOMO-LUMO gap reveals that the gap decreases with the increase in number of Si dopant atoms in ZnO nanosheet. These results global gave molecular electronics important electronic applications and help us to replace some oxygen atoms instead of silicon atoms in ZnO nanosheet.

Green synthesis of nanomaterials and its verity of applications have linked chemistry, biotechnology and environmental chemistry. Green process get more attention due to its easy handling and inertness to ecosystem. The selection of green synthesis and silver oxide nanoparticles (Ag₂O NPs) are purely based on its nontoxic behavior and promising activates. Eco-friendly process was applied for the synthesis of silver oxide nanoparticles (Ag₂O NPs) using Paeonia emodi (P. emodi) fresh leaves extract as reducing agent. The average crystallite size was found to be 38.29 nm, calculated from the FWHM of the diffraction bands of x-rays diffractometer (XRD). The morphological study was made by performing transmission electron microscopy (TEM) and scanning electron microscope (SEM) and the particles size estimated from the micrographs of both techniques are 38.29 and 86.4 nm respectively. The energy dispersive x-ray (EDX) was used to study the purity and percent composition of the Ag₂O NPs. The band gap energy (4.02 eV) and surface functional groups was studied by diffuse reflectance spectroscopy (DRS) and fourier transform infrared spectroscopy (FTIR) respectively. The 97.78% methylene blue (MB) was degraded in the presence of Ag₂O NPs and UV–visible light source in 180 min The antibacterial activity of the Ag₂O NPs were tested against Gram-positive (Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S aureus)) and Gram-negative (Escherichia coli (E coli) and Pseudomonas aeruginosa (P. aeruginosa) bacteria. It was found that the Ag₂O NPs have strong growth inhibiting activity against Gram-negative bacteria than Gram-positive bacteria.

In this paper, different contents of multi-layer graphenes (MLGs) were separately incorporated into cement pastes and cement mortars to study the electromagnetic shielding and absorbing properties of MLGs filled cementitious composites in the frequency range of 2–18 GHz. In order to verify the reliability of using testing electromagnetic parameters to calculate electromagnetic shielding and absorbing properties, the measured absorbing reflectivity of cementitious composites containing MLGs were compared with the calculated values. The influence mechanisms of MLGs on the electromagnetic properties of cementitious composites were also investigated. Results indicate that the electromagnetic shielding effectiveness and absolute reflectivity value of cement pastes with 10.0% MLGs achieve a maximum of 10.35 dB and 33 dB, respectively. Besides, cement mortars with 15.0% MLGs show the greatest increase of 95% in the electromagnetic shielding effectiveness, and the absolute reflectivity value reaches up to 18 dB, which is 9 times as high as cement mortars without MLGs. Generally, MLGs filled cement pastes perform better in electromagnetic properties than MLGs filler cement mortars. The electromagnetic wave absorption loss of cementitious composites filled MLGs is governed by dielectric loss, and there is basically no magnetic loss.

In this work, Zn_1-xGa_xO, (x = 0, 0.01, 0.02 and 0.03) powders were prepared using the hydrothermal method with accelerated-microwave heating system. The nanostructure Zn_1-xGa_xO were successfully fabricated via microwave heating method with presenting of the anisotropic hexagonal prism shape in perpendicular to c-axis and self-aggregated nano-particle. The Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) technique reveled the nanostructure particle size sample of the ZnO and the Ga-doped ZnO as in the range of 80–100 nm and 50–100 nm, respectively. The computer simulation showed the thermoelectric properties of ZnO enhancing by doping Gallium ZnO. The experimental results of thermoelectric properties for nanostructures Ga-doped ZnO nanomaterials was enhanced electrical conductivity and reduced thermal conductivity. The Seebeek value of the Ga-doped ZnO nanomaterials was difference from the ZnO-based. All ZT value of the Ga-doped ZnO nanomaterials were higher than that the ZnO-based. The highest ZT value of 0.08 was obtained from 2% Ga-doped ZnO at 773 K. The nanostructure of the Zn_1-xGa_xO nanomaterials were completely prepared by the hydrothermal-microwave heating with enhancing thermoelectric properties. The Ga-doped ZnO nanomaterials are potential materials for moderate temperature thermoelectric applications.

Cuprous iodide (CuI) was grown on the Si (100) and Cu films/Si(100) substrate by hydrothermal methods. Different nanostructured CuI have been obtained using hydrothermal reaction and hydrothermal evaporation methods. It has been found that all the nanostructured CuI films have a γ phase with polycrystalline structure. Having analyzed the photoluminescence (PL) character of nanostructured CuI, the origin of different PL emissions and the different growth mechanisms have been discussed. Then, the photoelectric properties of n-ZnO/p-CuI photodetector with UV light illumination under a different reverse bias have been investigated. Based on the current-voltage curve, the photocurrent to dark current ratio is approximately 80.8 at −3 V.

The present study deals with the vibration analysis of sandwich cylindrical shells with the functionally graded carbon nanotube reinforced composite (FG-CNTRC) face sheets resting on elastic medium under internal pressure. Two FG-CNTRC face sheets along with homogeneous core are considered as the sandwich cylindrical shell. The overall mechanical properties of CNT-reinforced composites are presented in accordance to the refined rule of mixture. Based on the higher-order shear deformation theory (HSDT) and in the context of the variational differential quadrature (VDQ) method, the discretized version of governing equations is provided. Validation of the proposed model is demonstrated. Several numerical results are also represented to study the impacts of various material and geometrical factors on the vibration analysis of sandwich cylindrical shells. The results reveal that in the case of constant total thickness, increasing the core-to-face sheet thickness ratio decreases the dimensionless frequencies.

Current-voltage characteristics of armchair and zigzag γ-graphyne nanotubes with three different diameters under uniaxial strain are investigated by using first-principles quantum transport calculations through density functional theory (DFT) and non-equilibrium Green's function (NEGF) method. It is shown that for a given value of bias voltage, the resulting current depends strongly on the applied load so that tensile and compressive strain can generate Negative Differential Resistance (NDR) mostly into the armchair nanotubes. Our study reveals that the rectification behavior of the systems is mainly due to the asymmetric electron transmission function distribution in the conduction and valence bands.

The CuO nanostrips are synthesized by simple low cost wet chemical route. Synthesized nanostrips are characterized by energy dispersive analysis of x-rays for chemical composition. The crystal structure of the CuO nanostrips is determined by x-ray diffraction. The CuO nanostrips posses monoclinic structure having lattice parameters as; a = 4.68, b = 3.42, c = 5.13, α = 90°, β = 99.54° and γ = 90°. The high-resolution transmission electron microscopy and scanning electron microscopy showed synthesized CuO has strip like morphology. The synthesized CuO nanostrips are dispersed in two transformer oils, one of make year 1997 and another of make year 2017. Four different CuO nanostrips concentrations (0.01, 0.02, 0.03, 0.04 vol%) are dispersed in the two transformer oils. The CuO-transformer oils mixing are done by ultrasonication. The stability of the prepared transformer nanofluids is confirmed by UV–vis spectroscopy and zeta potential method. The prepared transformer nanofluids are studied by ultrasonic interferometer. The ultrasonic study of the transformer nanofluids are done at high temperatures of 303 K, 313 K, 323 K, 333 K and 343 K. The obtained results are discussed in this paper.

Thermal ageing of nickel-base alloys can lead to the formation of brittle ordered phases, but the direct study of these phases is challenging. Nanoindentation is used in this study as an alternative technique to determine the extent of short-range ordering (SRO) in thermally aged Alloy 690 TT. Two methods are used for obtaining both qualitative (depth sensitivity) and quantitative (spatial stability) results, which are compared to data from metallography, microhardness and atomic force microscopy in order to discriminate between factors affecting the hardness. When intergranular precipitation and grain size become dominant factors with increasing indentation loads, nanoindentation at low loads enables to distinct within-grain hardness increase related to SRO.

Investigation of undoped and lithium doped ZnO nano films deposited on glass substrates by sol-gel spin coating method have been carried out. The structural and morphological properties of the films with optimum post annealing temperature of 350 °C have been investigated using x-ray Diffractometer (XRD) and Field emission scanning electron microscopy (FESEM) respectively. The XRD spectrum reveals that all the synthesised samples have single crystal structure having strong intense peak oriented along (002) c-axis. Crystalline size of undoped and Li doped ZnO nano films were deduced to be 34.66 nm and 32.59 nm respectively. FESEM exhibits uniform chromosome type structure. Nano films show transmittance above 90% in the range of wavelength 350 nm to 800 nm. I–V characteristic shows linear and ohmic behaviour.

Graphene nanoribbon (GNR) is a strip and 1D shape of graphene which can be an appropriate candidate for gas sensing application due to its significant electrical and chemical characteristic. In this study, graphene nanoribbon is employed for the NH₃ detection process. The chemical approach is applied for unzipping MWCNTs by using KMnO4, as an oxidative material in graphene oxide nanoribbon synthesis process. The gold comb-like electrodes as a sensor structure is produced by standard deposition and photolithography methods. The quality of the synthesized GNRs is investigated by different analyses such as SEM, XRD, Raman Spectroscopy, and FTIR. In addition to GNR sensor preparation, AuGNR sensor is fabricated by gold sputtering deposition on a GNR sensor surface. The experimental results for sensors indicate that AuGNR and GNR sensors could be the appropriate choices for NH₃ detection. The experimental tests for AuGNR and GNR sensors are performed for different NH₃ concentration at room temperature which showed 34% and 12.1% response for 25 ppm NH₃ respectively. Furthermore, in 25 ppm for the AuGNR sensor, the sensor shows 224 s for response time, and 178 s for recovery time for a graphene-based sensor. All the tests are carried out at room temperature.

Tendency of magnetic nanoparticles to agglomerate can be minimized by dispersing them in suitable inert matrix. This paper reports the synthesis, structural, spectral and magnetic properties of cobalt ferrite nanoparticles dispersed in silica matrix. Samples were characterized using x ray Diffractometry (XRD), Infrared Spectroscopy (IR), Transmission Electron Microscopy (TEM) and Vibrating Sample Magnetometry (VSM). It was observed that silica matrix retains the properties like crystal structure, cation distribution, band positions in IR spectra etc. Crystallite sizes were found to change from 15.1 nm to 17.6 nm with increased SiO₂. Magnetic properties were observed to be significantly affected due to altered inter-particle distances and change in crystallite size after dispersion in the matrix. A gradual reduction in saturation magnetization from 68.7 emu g⁻¹ to 4.77 emu g⁻¹ was observed with augmented SiO₂ content indicating that the magnetic properties can be tuned by varying the ferrite-silica ratio. Further, the catalytic activity of a typical sample was also studied and a maximum yield of 78% was obtained at a reaction temperature of 70 °C with isopropyl alcohol as a solvent for the synthesis of 2 Phenylbenzimidazol.

The endohedral functionalization of single-walled carbon nanotubes with molecular species, nanowires (NWs) and nanoparticles is of great importance for fabrication and development of nanoelecronic devices, drug delivery and energy storage applications. This research intends to explore the axial buckling behavior of the endohedrally functionalized single-walled carbon nanotubes (SWCNTs) by various metallic NWs (mNW@SWCNT), i.e. aluminum, copper, iron, sodium, nickel (AlNW, CuNW, FeNW, NaNW, NiNW), considering all possible pentagonal configurations. Employing the molecular dynamics (MD) simulations, the results demonstrate that the structurally stable radius of SWCNTs for successful endohedral functionalization of SWCNTs with pentagonal NWs are different. Considering buckling analysis of models, it is observed that NWs, solely, cannot tolerate any axial compressive load and their structure becomes dramatically unstable under mechanical force. By inserting NWs inside SWCNTs, their pentagonal structures during simulation are preserved due to Vdw interaction of NW and SWCNT until buckling occurs. Moreover, the buckling simulation results indicate that by increasing the length, the critical force of mNW@SWCNT decreases and approximately tends to that of pure SWCNTs which is more considerable for AlNWs. Also, in the particular length, the encapsulation of NWs inside the SWCNTs causes a considerable increase in the critical buckling forces particularly in smaller lengths. According to the attained results, functionalization of SWCNTs with E and S configuration of AlNWs improves the structural stability of SWCNTs more pronounced than other pentagonal NWs.

We investigate the transport properties of defected graphene nanoribbons with single C vacancy using non-equilibrium Green's function formalism within the tight-binding model approach. The insights derived from the analysis of geometric and electronic structure allow us to infer the localized nature of the defect-induced structure relaxation and transport properties. We show that the single vacancy position and concentration in graphene nanoribbons can alter the transmission spectrum and current-voltage characteristics. We consider the dependence of the transport properties on the local strain caused by the C vacancy positions and concentration. We conclude that such defect profoundly modifies the mechanical and electronic properties of the graphene nanoribbons, and introduce new transport properties by allowing the atomic rearrangement.

An efficient UV and visible light sensitive Cd substituted ZnO quantum dots (Cd-ZnO QDs) are synthesized through a facile soft-chemical approach. Cd-ZnO QDs are well characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV–vis) and x-ray photoelectron spectroscopy (XPS). TEM micrographs of Cd-ZnO QDs indicates well-spherical particles of size ~5–6 nm. The optical analysis of Cd-ZnO QDs confirms that the band gap and defect emission are strongly dependent on the Cd concentration. Moreover, the intensity of defect emission increases with increase of Cd substition from 0 to 3% which indicates that Cd substitution enhances defect emission of ZnO. Further, increase in the Cd concentration (5 and 10%) suppresses the defect emission. Such type of variation in Cd-ZnO QDs may be ascribed due to the non-radiative energy transfer. Under UV light, Cd₃-ZnO QDs shows an excellent photocatalytic activity, whereas under solar light Cd₁₀-ZnO QDs shows enhanced photocatalytic activity as compared to pristine ZnO. The enhanced photocatalytic activity of Cd-ZnO QDs is ascribed to the reduction in recombination rate, higher defect concentration and absorption in visible region. Additionally, Cd₃-ZnO QDs exhibits a good antibacterial activity. Higher defect concentration and accumulation of QDs on the cell membrane may trigger the ROS generation and cause the lipid peroxidation. This seems to be possible mechansim for the antibacterial activity of Cd₃-ZnO QDs.

We report herein on the preparation of a superhydrophobic surface by high-speed wire electrical discharge machining on the surface of a 7075 aluminium alloy without any chemical treatment. The morphology and the anti-icing, anti-wear and anti-corrosion properties of the superhydrophobic surface were characterised by scanning electron microscopy, contact angle measurements, a custom-made experimental apparatus, a universal mechanical tester and an electrochemical workstation, respectively. Our results indicated that the superhydrophobic specimen had a water contact angle of 154.3 ± 0.5°. The anti-icing, anti-corrosion and anti-wear properties of the prepared specimen were improved by approximately 70%, 110% and 160%, respectively. Moreover, the artificial surface could maintain its anti-icing properties even in the event of surface damage.

In this work, functionally graded material (FGM) of Titanium/nano-hydroxyapatite were fabricated using powder metallurgy method as dental implant and their biocompatibility, static strength and fatigue characteristics in different volume fraction exponents were investigated using experimental and numerical methods. For producing hydroxyapatite powder, for the first time, drilling method was used instead of ball milling. First, cow bones were drilled using a 2 mm drill and the resulting powder was converted to nanostructured hydroxyapatite through specific heat treatment. Then FGM of titanium/nano-hydroxyapatite at different volume fractions and features such as bioactivity, hardness, microstructures, and fatigue strength of the FGM implants were investigated using empirical and numerical methods. The effect of changes in volume fraction exponents on each of these parameters was also investigated. According to the results, biocompatibility of titanium/hydroxyapatite FGM dental implants was confirmed after submerging in simulated body fluid (SBF) using scanning electron microscope (SEM) and ion concentration measurement (ICP) methods and were obtain that with increase in the soaking time in SFB, the rate of formation of bone-like apatite on the surface of the sample had an increasing trend and the concentration of calcium and phosphorous ions in the solution decreases which shows the formation of apatite. The samples were also in the safe zone after fatigue loading using finite element analysis. The result of numerical analysis of fatigue life for the fabricated dental implants showed that after 5 years, just %45 of the critical layer life which is pure HA remained; it means the fabricated dental implant can be work at least for 9 years without fatigue fracture. The effect of volume fraction exponents of FGM samples on a change gradient of mechanical properties and biocompatibility was investigated and according to the results, volume fraction exponent of N = 2/3 showed the best performance.

The modification effects of nanosilica, a widely used nanomaterial, on the cement grain/C–S–H gel interface of cement-based material at early ages are investigated. The mechanical properties, morphology, and chemical composition of the interface at nano-size are explored by quantitative modulus mapping based on scanning probe microscopy (SPM) and tribological nanoscratch coupled with scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), for the interface in the form of an ultra-thin layer requires high spatial resolution techniques. The interface width as determined by the analysis on the variation of storage modulus and coefficient of friction (COF) is around 200 nm, which is irrelevant to the nanosilica addition; however, the incorporation of nanosilica improves the nanomechanical performance of the interface significantly. The densification of the interfacial region by nanosilica, which is mainly attributed to the pore refinement, is confirmed by morphological characterization. It has been proven by EDS analysis that Ca/Si ratio provides evidence for the location of the interface and the modification effects by nanosilica.

In this study, the influence of geometrical parameters on the absorption, the external quantum efficiency (EQE), open-circuit voltage (V_oc) and short-circuit current (J_sc) of GaAs/In_0.2Ga_0.8As cylindrical core–shell nanowire (NW) solar cell have been investigated, using a Finite-Difference Time-Domain (FDTD) modeling method. The results show that tuning the nanowire physical dimensions can give high absorption of the incident photons.

This work demonstrates the optical responses of the graphene coated silver-aluminum (Ag–Al) alloys' dimer in the presence of humid ambient using Discrete Dipole Approximation (DDA) as a numerical technique. The non-equivalent spherical shape of graphene coated Ag–Al alloy dimer has been considered for this study, where the plasmonic coupling supports both the bonding and anti-bonding modes which lies in higher and lower wavelength region, respectively. The combined effect of these modes provide a broad resonant spectrum, which mainly influenced by the inter-particle separation between graphene coated alloy dimer. As the interparticle separation decreases, the resonance wavelength shows a red spectral shift with increase in the magnitude of local electric field. The results of proposed geometry provide a good support for the various applications in photovoltaics and photonics.

The present work describes the synthesis of iron oxide magnetic nanoparticles (IONP) and citrate-capped IONP (IONP-citrate), via conventional chemical routes and ultrasound-assisted approaches. IONP and IONP-citrate samples were characterized by x-ray diffraction (XRD), vibrational spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic light scattering (DLS). XRD analyses allowed the crystalline structure determination, evidencing the formation of magnetite phase in all samples. FTIR provided evidence of chemical structures involving hydroxylated species at IONP surface, replaced by citrate during capping, to obtain IONP-citrate samples. Mean particle size, determined from DLS, varied from (approximately) 172 to 34 nm, decreasing as the energy transferred from the ultrasound device during synthesis increases. SEM images showed a regular spherical morphology, regardless the capping or perturbation imposed during synthesis.

A copper anode was used in sodium carbonate solutions to prepare nanoparticles of copper carbonates. To reach the best results, the parameters affecting the preparation procedure were evaluated and optimized based on the Taguchi robust design (TRD), and it was found that the size of the resulting copper carbonates particles could be managed by applying optimal values of parameters such as electrolysis voltage, carbonate concentration, stirring rate and the temperature. To evaluate how significantly the factors influence the size of the particles, analysis of variance (ANOVA) was used, and the results indicated that the electrolysis voltage, carbonates concentration, and stirring rate affect the dimensions of the particles to a high degree. The optimal conditions were also evaluated. Further, the copper carbonate particles were used as the precursor in a solid-state thermal decomposition reaction intended for forming nanostructured CuO particles. All products were studied through SEM, XRD, TG-DTA, and FT-IR techniques and also those of optimal properties were evaluated as photocatalytic species for application in the UV-induced degradation (UVID) of methylene blue (MB).

Three Dimensional button, flower and sphere shaped microstructure of silver nanoparticles dispersed in dextran sulfate matrix were synthesized using silver nitrate, trisodium citrate and dextran sulfate. Three different amount of dextran sulfate (2 drops, 10 drops and 15 drops) were added to each 10 ml of silver nanoparticles to make three different solution mixtures, which was then subjected to different characterization techniques. The XRD study of flower shaped dextran sulfate stabilized silver nanoparticles showed a diffraction pattern corresponding to face centered cubic structure of Ag crystals. The FESEM image shows a well defined three dimensional button shaped microstructure for 2 drops of dextran sulfate, flower shaped microstructure for 10 drops of dextran sulfate and sphere shaped microstructure for 15 drops of dextran sulfate. Based on the morphological structure of the synthesized nanoparticle the absorption property was discussed, the absorption band varied from 429 nm to 434 nm. The nanoparticles prepared using dextran sulfate of high concentration (15 drops) shows a blue shift in absorbance spectra, indicating smaller size of AgNPs with high absorbance property. The results reveal that the surface morphology affects the absorption behavior of the nanoparticles. The results of cytotoxicity assay against human vero cell lines revealed that flower shaped dextran stabilized AgNPs shows ≥ 90% cell viability indicating the biocompatibility of the nanoparticles. The In-vitro anticancer activity of the synthesized Ag-DS nanoparticles against human breast cancer cell line MCF-7, was studied. The results of the present study indicated that the Ag-DS nanoparticles can be a potent anticancer agent.

Silver nanoparticles were synthesized by direct exposure of mixtures of silver nitrate and sodium citrate to sunlight. The reactions were performed near noon, at ∼32 °C during winter, varying the precursors ratio. Nanoparticles were characterized by optical absorption spectroscopy, scanning transmission electron microscopy, as well as proton nuclear magnetic resonance spectroscopy. The kinetic of nanoparticles formation was followed by the temporal evolution of absorbance, and analyzed by using Finke-Watzky two-step model, showing good fit to experimental data. A possible reaction mechanism for the formation of silver nanoparticles is proposed based in the experimental results and the kinetic analysis. This mechanism consists of multiple stages, where the formation of complexes between citrate and cationic silver dimers limits the nucleation process and determines the final size and morphology of the nanoparticles. The proposed approach offers a simple, economic and ecological route for the synthesis of silver nanoparticles.

In this study, for the first time, we report the synthesis of α-FeOOH with self-organized nanofibrous morphology by the use of widely available FeSO₄·7H₂O precursor and methanol-assisted reflux. The as obtained nanofibrous goethite phase shows high surface area of 104.1 m²·g⁻¹. This material was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and Brunauer–Emmett–Teller surface area analysis. These nanofibers were able to effectively extract Cd²⁺ from wastewater in conjunction with molecular monolayer adsorption behavior consistent with a pseudo-second-order kinetic model. The maximum adsorption capacity was 181.7 mg·g⁻¹, which is superior to values obtained from most other adsorbents for Cd²⁺ removal. The adsorption capacity was almost unchanged after five adsorption–desorption cycles. Self-organizing α-FeOOH nanofiber networks appear to be promising adsorbents for the remediation of water polluted with Cd²⁺.

Molecular dynamics (MD) simulation was employed to scrutinize behavior of chitosan nanoparticles (CS-NPs) as a nanocarrier for donepezil and rivastigmine drug molecules. Accordingly, modeling of CS-NPs was carried out based on experimental method (i.e., spontaneous emulsifications). The comparison of the radius of gyration of polymer (R_g) and equilibrium distance (r) of donepezil molecules indicate that CS-NPs is spherically agglomerated before and after addition of ions. However, the behavior of CS-NPs as carrier of rivastigmine molecules changed after addition of ions. The use of CS-NPs length in three dimensions (xyz) and the nearest distance of center of mass (COM) of drug molecules relative to the CS-NPs (r_d) demonstrate that entanglement of polymer chains is decreased. Furthermore, behavior of the polymer is confirmed by intra- and/or inter-molecular interactions analysis of components of systems (i.e., CS-NP, drug molecules and ions) and diffusion coefficients of drug molecules. In this regard, the slope of MSD curve versus time is sharply increased in presence of ions in rivastigmine systems due to opening of polymeric chains and release of some of drug molecules. Therefore, drug loading capacity in CS-NPs is decreased in rivastigmine systems relative to donepezil systems. This assessment showed good agreement between results of MD and others experimental work.

Alkali metal ions such as lithium, sodium and potassium are essential chemical species present in biological fluids (0.5–1.2 mM) and less hazardous quantity (0.9 μM–12 μM) present in drinking water. Lithium salts are used in pharmaceuticals, in ores and minerals, in Li-ion batteries. Ingestion of water source containing lithium concentration above 0.2 mM affects normal functioning of the body. Hence it is important to detect these ions in potable water. Here, a conjugated molecule based sensor for detection of lithium ion in water is developed. The conjugated molecule has a receptor moiety to capture the ion. The conjugated molecule interaction with alkali metal ions - Li⁺, Na⁺ and K⁺ is studied by density functional theory and interference analysis. The resistive based sensor is fabricated and device characteristics are studied. The experimental and simulation results suggest that the conjugated molecule interaction specifically with Li⁺ is relatively stronger. The lower limit of detection of the sensor is observed to be 0.05 mM. This limit is within the range of the lithium ion concentration found in biological fluids.

The furfurylaminium 2-chloro-5-nitrobenzoate (FC) is a modernized organic material possessing enhanced order three nonlinearity. The crystals of FC of dimensions 17 × 4 × 2 mm³ were yielded on slow evaporation with the usage of ethanol-water mixed solvent (1:1). The precise peaks in powder XRD analysis reveal the crystalline property of the compound. The lattice parameters was estimated (a = 11.77 ± 0.012 Å, b = 6.84 ± 0.012 Å and c = 16.33 ± 0.028 Å and volume = 1342 ų) from powder XRD using XRDA software. The FC crystal corresponds to the system of monoclinic with the space group P2₁/c. The UV-visible spectrum of FC crystal sample furnishes the lower cut off wavelength (325 nm) and the band gap (3.57 eV) for FC crystal. The dispersion factors Eo and E_d was calculated to be 4.24 eV and 15.20 eV respectively from Wemple and Di Domenico single oscillator model. Using these values, the oscillator strength value was calculated to be 64.5134 (eV)² and the moments of optical spectra was estimated to be M₋₁ = 3.580 (eV) ² and M₋₃ = 0.198 (eV) ². The optical conductivity (σ) value of FC crystal at 532 nm was found out to be 0.21 × 10¹⁰ s⁻¹. A red emission peak at 691 nm was obtained in photoluminescence spectra when the FC sample was excited at 325 nm. Single shot LDT value for FC crystal was calculated to be 14.40 GW cm⁻². The third order optical susceptibility (χ⁽³⁾) of the molecule was enumerated as 4.02 × 10⁻⁶ esu from Z-scan technique and the second order hyperpolarizability (γ) value is calculated to be 2.64 × 10⁻³⁵ esu. The coupling factor (ρ*) is estimated to be 0.047, on utilizing the calculated values of (Re χ⁽³⁾ = 0.19 × 10⁻⁶ esu) and (Im χ⁽³⁾ = 0.19 × 10⁻⁶ esu) from Z scan technique. The specific heat capacity (C_p) at 50 °C was calculated as 1.5810 (Jg⁻¹K⁻¹) and thermal diffusivity (κ) as 1.750 × 10⁻⁶ m² s⁻¹. Thus using (κ) value the thermo-optic coefficient was deliberated to be 5.34 × 10⁻⁶ K⁻¹. The maximum output power of FC indicates its optical limiting behaviour. The Mayer's index specifies the grown FC crystal to the category of soft material and the various mechanical parameters were enumerated and reported.

Post-production annealing which improves the power conversion efficiency of the P3HT:PCBM-based organic cells are very important process. Lots of various annealing temperatures and annealing times have been used for annealing process in previous studies but not any criteria was taken as a basis for determination of annealing temperature. In this study annealing temperature was optimized for annealing time of 3 min ITO-PEDOT:PSS/P3HT:PCBM/Al was fabricated at the weight ratio of 12:8 for P3HT:PCBM. Organic solar cells were annealed at different annealing temperatures in the range of 80 °C–160 °C. The variation of external quantum efficiency (EQE) with annealing temperature was obtained. The higher EQE was obtained at 120 °C. Thus, 120 °C was determined as optimum annealing temperature. The aging experiments were performed under constant humidity, illumination and atmospheric conditions. It has been observed that the post- product annealed at 120 °C solar cells have more longer life time and more stable compared with the non-annealed cell and other annealed solar cells.

Based on the present research in the self-assembly of azopyridine derivatives, we designed a series of representative derivatives: lipophilic compounds with rigid chains(AzoPyChol), lipophilic compounds with flexible chains(AzoPyC16), amphiphilic compounds(AzoPyAp). The derivatives interacted with inorganic acid (concentrated HCl) to form hydrochloride salts (AzoPyChol-HCl, AzoPyC16-HCl and AzoPyAp-HCl). According to the results of SEM images and UV–vis absorption spectra, AzoPyAp-HCl showed better morphological stability in different solvents. The changes in self-assembly behavior of hydrochloride salts were proved via XRD and fluorescence analysis. Liquid crystal of the azopyridine derivatives were illustrated by differential scanning calorimetry(DSC) and polarizing microscope(POM).

New type of optoacoustic transducer containing monolayer of dielectric spheres is presented. Experiments of the ultrasound generation by the single nanosecond laser pulses (2nd harmonic of Nd:YAG) in a liquid absorbing ink were carried out. It was found that the irradiation of the liquid through a mask containing the monolayer of glass spheres result in the greater ultrasound intensity and the broader spectrum compared to the same setup without the mask. The effect is explained by the focusing of the laser light by the spheres. The laser intensity is being concentrated into the multitude of the 'hot spots' where the high-frequency ultrasound is generated.

Alloys based on Cu–Zr–Al are known for their relative easiness in producing glassy structures. However, several important aspects related to the microstructure and the Glass Forming Ability (GFA) are still not well understood. Here, we present results referring to Molecular Dynamics simulations (MD) of rapidly quenched glassy Cu–Zr–Al of two compositions. GFAs were investigated, both experimentally and by MD simulations, using x-ray diffraction, High-Resolution Transmission Electron microscopy and Differential Scanning Calorimetry, while the structural evolution upon cooling was investigated by simulations using radial distribution functions, Voronoi tessellation analysis, and volume–temperature curves. Moreover, the viscosity evolution as well as the glass transition temperature and the fragility parameters were also estimated. Good agreement was found between the MD simulation results and the experimental data. It came out that the Zr–rich composition resulted in a 'stronger' metallic liquid than the Cu–rich composition. In addition, we found that the evolution of distorted into well shaped icosahedral clusters upon solidification, is a determining factor for the stability of the Zr–rich metallic glass. Moreover, we propose a new criterion based on a weighted average of the atomic radius ratio that has been found promising in adequately predicting glass forming abilities.

Ceramic materials underwent the impact erosion of abrasive particles were investigated in this research. A numerical model was developed to simulate the impact particle and aluminum nitride target. The damage and failure behavior of impacted region of material was described by adopting a rate-dependent constitutive model. The dynamic response of material subjected to impact was investigated through analyzing the mechanism of crack formation and the evolution of stress field. The results indicated that fracture damage is characterized by median and lateral cracks induced by tensile stress. Moreover, the fraction of energy consumed in friction and scratching is higher under oblique impact condition, which resulting in slighter fracture failure.

In the present paper, the MnO₂ films have been deposited on stainless steel support by potentiostatic mode of electrodeposition at different times. The x-ray diffraction, Fourier transform infrared spectroscopy along with Energy-dispersive x-ray spectroscopy analysis confirmed formation of amorphous MnO₂ coating. The surface analysis by field emission scanning electron microscope indicated development of fractures with increasing film thickness. The in situ measurement of stress to the substrate and MnO₂ film thickness during deposition is performed by non-destructive double exposure digital holographic interferometry (DEDHI) technique. It was observed that the stress to the substrate decreases with increasing MnO₂ film thickness. This study opens application of DEDHI for non-destructive measurement using simple mathematical interpretation.

This work demonstrates bulk-type up-conversion biomaterials which could be used as a bone repair material with the ability to monitor bone mineralization. Er³⁺/Yb³⁺ co-doped Ca-Si-Ti (CST3: TiO₂ content is 30 mol%) bulk biomaterials were prepared via containerless processing technique in an aerodynamic levitation furnace and with subsequently heat treatment. The up-conversion fluorescence property was influenced by Yb³⁺ doping concentration, heat-treatment and mineralization in simulated body fluid (SBF). Optimum emission intensities were obtained for the sample with 20 mol% of Yb³⁺ doping concentration and heat treatment at 937 °C for 2 h. Hydroxyapatite (HAP) deposition was observed on the surface of the samples after soaking in SBF for 14 days, and the up-conversion fluorescence intensity of the samples decreased with the increase of soaking time. This indicates that Er³⁺/Yb³⁺ co-doped CST3 materials are bioactive, in which the HAP mineralization in bone repair could be monitored by measuring the intensity change of up-conversion fluorescence.

The sensitivity of high-precision measurements is crucially affected by the mechanical losses of the involved materials. In systems incorporating highly reflective elements based on amorphous Bragg reflectors, the mechanical losses of the coating materials have to be minimized. In this contribution, we report on the detailed fabrication of SiO₂ microcantilever arrays to study such mechanical losses. The fabrication steps, consisting of pattern transfer, anisotropic and isotropic dry etching, have been optimized to be employed on both thermally grown and sputtered SiO₂ samples. The cantilevers released from the Si substrate show a deviation of only 2% from the design, confirming a high selectivity of the etching processes. The mechanical loss measurements of the cantilevers are carried out using a laser-based optical setup, revealing a mechanical loss of 1.2 × 10⁻³.

Precursor sol with a high solid content is significant for alumina fiber synthesis. In the present work, alumina precursor sols used for preparing alumina fibers were synthesized by dissolving aluminum powder (AP) into a mixture of formic acid, acetic acid and deionized water. The effects of preparation temperatures on solubility of AP, structure of the synthesized sols and gels were investigated. The reaction mechanism of hydrolysis and polymerization was also studied. Based on the reaction mechanism, alumina precursor sol with a high solid content was acquired through the adjustment of temperature. The results revealed that all the sols synthesized at the temperature from 85 °C to 115 °C consisted of polymers, linear oligomers and monomeric species. Colloidal particles presented spherical shape with a uniform size. However, AP cannot dissolve entirely at 85 °C and white precipitates (HO)Al(CH₃COO)₂ was produced at 105 °C and 115 °C. AP had the highest dissolution degree at 95 °C. A colorless and transparent alumina sol with the highest solid content was acquired at this temperature. The structure of concentrated gels was also discussed. It was revealed that network polymers increased when using sols synthesized at temperature above 105 °C, which were negative for spinning. Continuous green fibers were obtained successfully using the alumina sol prepared at 95 °C.

In this work, glass fiber felt (GFF) was prepared via wet beating method to explore the correlation between the physical properties (air permeability, thermal conductivity and acoustic property) and microstructure. The consequence presents that increasing the layers of GFF could enlarge the average pore size, but almost have no effect on air permeability. It also finds that the thermal insulation property and acoustic property could be enhanced via the increase layers of GFF. More the layers leads to a superior sound insulation property. This is because that layered structure can avoid thermal bridge to reduce thermal conductivity. Besides, the comparatively big mismatching among characteristic acoustic impedances (CAIs) of layered structure result in multi-reflection, which will causing the increasing of acoustic property.

It is very important to increase the contrast ratio in liquid crystal display (LCD) TV using polymer-stabilized vertical alignment (PS-VA) mode. The luminance of the black state is greatly reduced by changing the parameters of the polarizer, the color filter, and the liquid crystal. However, these have the side effect of reducing the characteristics such as the transmittance, the response time, and the viewing angle. In this paper, the luminance of the black state can be reduced by lowering the stress induced retardation at the edge of pixel electrode without changing the materials in the PS-VA mode. It has been shown for the first time that the stress difference in the heterogeneous layers such as amorphous indium zinc oxide (a-IZO) and amorphous silicon nitride (a-SiN_x) can optically create birefringence in the microscopic region. By controlling the stress difference in the heterogeneous membrane, the microscopic-stress-induced retardation (MSIR) could be lowered and the contrast ratio of the PS-VA mode could be increased up to 10%.

Environmental policies set the boundary conditions for industries and commercial market regarding the maximum utilization of biodegradable material. In this context, the current research work deals with the development of cellulosic fiber filled epoxy composites and test for biodegradability in the natural soil environment. Moreover, an experimental investigation has been carried out to study the effect of relative fiber volume content and alkaline treatment of cellulosic fibers on the biodegradability and mechanical properties of Pineapple leaf/Coir fiber reinforced hybrid epoxy composites. To accomplish the desired objectives, the total of 23 biocomposite specimens (untreated and alkali-treated) has been developed by hand lay-up molding technique and test for tensile, flexural, impact, and weight loss properties as per ASTM standard. In all composite specimens, the total fiber to polymer resin ratio was kept fixed at 40:60 (v/v). The total of four samples for each composite specimen was tested and their average values were reported. The experimental results showed that the hybrid composites exhibit rapid loss of mechanical strength in natural soil environment than the pure Pineapple leaf-Epoxy composite. The single pineapple leaf fiber reinforced material revealed a higher rate of biodegradation and greater loss of tensile and flexural strength as compared to the pure Coir-Epoxy composite. The alkali-treated coir fiber enriched composites have a higher weight loss and greater reduction in mechanical strength than the untreated one. The mechanical strength and biodegradability of an epoxy thermoset were increased with the incorporation of PALF and COIR fibers which leads to easy and smooth adoption in engineering applications.

With the advent of additive manufacturing, fabrication of complex structures with high efficiency for energy absorption and blast and impact mitigation has entered a new era. In this research the role of the architecture and material properties on the static and dynamic energy absorption properties of additively-manufactured complex cellular structures out of two different materials were studied under puncture and crush tests. A finite element simulation of the unit cell was also conducted to study the effect of loading rate on the final response of the material where the results showed good agreement with the experimental observations. It is shown that the studied additively manufactured structures were able to recover their shape significantly after a major deformation due to the impact. These results show the potential of additive manufacturing as a versatile tool for creating structures with complex geometries for energy absorption.

Continuous glass fibers were added through extruder head into recycled polyethylene terephthalate/polyethylene (r-PET/PE) alloy to form a composite named long fiber reinforced recycled thermoplastic (LFRT). By pressing plate, products similar to fiberglass were further made. Results of mechanical properties tests showed that the addition of glass fibers increased tensile and flexural strength of LFRT more than 3 and 7 times compared with that of basic material, respectively. In accord with interfacial properties exhibited by contact angle tests, differential scanning calorimetry and scanning electron microscope showed that raising extrusion and hot-pressing temperature resulted in the improving of compatibility between glass fibers and alloy. Dynamic mechanical analysis reported that glass fibers improved the heat deflection temperature greatly.

Quaternized low-crystalline poly(butylene succinate) (PBS) was synthesized with glycidyl trimethyl ammonium chloride (GTMA) by quaterisation reaction. The mechanical properties and thermal stability of quaternized low-crystalline PBS with different GTMA contents were investigated. It was found that when 5% GTMA was added, the mechanical properties were most favorable. The DSC and TGA results showed that as the GTMA content increased, the thermal stability of quaternized PBS was reinforced, the thermal decomposition temperature increased by 13 °C. The results showed that the quaternized low-crystalline PBS exhibited the excellent thermal and mechanical properties. Meanwhile, the crystallinity of quaternized PBS decreased and its contact angle is higher than the pure PBS. It could lay a foundation of the application of low-crystalline PBS composite in different fields through the research of various GTMA contents.

Photoelasticity method was used to map the stress field around the graphene nanoplates (GnPs) coated carbon fiber strand reinforced in a polymer matrix. Carbon fiber strand (0.4 mm diameter, containing 40 carbon fibers) was considered. The composite was subjected to diametrical compression. The models were loaded under partial edge compression having 0°, 45° and 90° orientation of fiber strand with respect to loading axis. Typical isochromatic fringe patterns were observed using circular polariscope which indicated that GnPs coated carbon fiber strand inferred the direction of isochromatics. Stress concentration near the fiber region was observed. The isochromatics were slightly bent towards fiber strand which showed the strong adhesion of fiber strand with the polymer matrix. The fringe order calculated from orthotropic Mohr's circle relevance of fringe order was different from isotropic fringe order. The isochromatic fringe pattern for composite with 0° fiber orientation was almost similar to pure epoxy. This showed that the compressive behavior of fabricated 0° oriented GnPs coated carbon fiber strand composite was almost similar to pure epoxy. The calculated values of stresses at the center of the disc showed that composite with 0° orientation of fiber strand was most effective in stress sharing. The calculation of stress fringevalue for 45° orientation of fiber strand showed that aligning fiber strand at 45° doesn't represent the case of pure shear in fiber reinforced composites. However, the deviation from pure shear was very less

Polyimides (PIs) and their nanocomposites may render quite high dielectric loss under high frequency (HF) electrical stresses, which will significantly affect the insulation properties and operating lifetime of the equipment when the composite materials are used in the high-voltage and large-capacity power electronics transformers (HFPTs). In this paper, the phenyl thioether groups of various molar ratios were introduced into the diamine residue as to prepare modified PI films via alternating copolymerization method. Frequency-domain dielectric spectrum and high frequency surface discharge were adopted to study the HF electrical properties. The results indicated that with the increase of the phenyl thioether content, the dielectric loss factor firstly decreased and thereafter rose up again, while the lowest arrived at 9.29 × 10^–4 for a PI film incorporating 40% phenyl thioether content, which case also presented the longest endurance lifetime against surface discharge tests at 15 kHz. Based the UV–vis tests on the charge transfer complexation, further analysis verified that for the 40% molar content of phenyl thioether in the PI molecule, it was the weak charge transfer characteristics that resulted in the smallest stacking structure of the ordered molecular chain in the film, which led to the weakest lossy polarization under the HF alternating electric field and manifested the minimal dielectric loss factor accordingly. The proposed research presents a feasible technological approach to regulate HF electrical properties of the modified PI films.

Six kinds of 2D T700/E44 composites with pressure-free curing times of 40 min, 60 min, 80 min, 100 min, 120 min and 140 min are prepared by improved compression molding process (ICM). The macroscopic morphology of the composites is satisfactory. The microstructure observation and bending performance tests show that composites have poor infiltration effect. When the pressure-free curing time is less than 80 min, defects are easy to occur such as insufficient infiltration and voids. Bad infiltration and void defects will lead to poor continuity of carbon fiber and resin, and their bending fracture will also be unreasonable, so the bending strength of composite at 40 min is 275 MPa. The infiltration effect is gradually improved with the increase of pressure-free heating curing time. However, when the pressure-free heating curing time reaches 120 min or more, the infiltration effect of the composites is deteriorated, and this is due to excessive infiltration time and extrusion force in subsequent heating extrusion infiltration process. Defects such as fiber aggregation and uneven infiltration are prone to occur, and bending strength of composites reduces to 380 MPa. When the pressure-free curing time is 100 min, the infiltration effect of the prepared composite is satisfactory, and the imbalanced infiltration and hole defects are effectively eliminated. The bending fracture of composite material is uneven, carbon fibers and resin play the roles of reinforcement and transferring loads effectively respectively, so the bending strength of the prepared 2D T700/E44 composite reaches 730 MPa.

Tone reversal in electron beam lithography when using polymethyl methacrylate (PMMA) as a resist is well known. At low electron beam dose, chain scissioning—resulting in positive tone lithography, is observed in PMMA. However, above a certain threshold dose, electron beam exposure results in cross-linking of PMMA, enabling negative tone resist action. We describe a similar phenomenon in PMMA (containing Irgacure 379—a free radical generator)—brought about through UV radiation exposure at 365 nm wavelength. The photo-active Irgacure 379 serves two purposes here: making PMMA sensitive to wavelengths as short as 365 nm (i-line) and amplifying the free radical concentration so that the tone reversal could be observed at relatively low UV dose. Thus, an optical analogue of the well-known tone reversal seen in electron beam lithography exists where the reversal is brought about by changing the intensity of UV illumination on PMMA containing a certain amount of Irgacure 379.

The influence of barium sulfate (BaSO₄) filler on the woven natural fiber Aloevera/Hemp/flax hybrid composites behavior is studied. The hybrid composite mechanical behaviors are characterized by tensile, impact and flexural testing. The viscoelastic properties are assessed (DMA) by storage modulus (E'), loss modulus (E'') and damping factor (Tan δ). The heterogeneity of the hybrid composite is analyzed by cole cole plot. The scanning electron microscope fractographical images reveal the fiber fracture, fiber pullout, voids and dispersion of BaSO₄ particles. The obtained result shows that the effect of BaSO₄ in AHB (Aloevera/Hemp/BaSO₄) composite minimizes the flexural modulus by 18% and fail to exhibit the significant improvement in the FHB (Flax/Hemp/BaSO₄) composite (0.06%). In addition to that the filler enhances the loss modulus and damping factor of the composite. In the glass transition region the maximum storage modulus is recorded in FHB composite and minimum in AH (Aloevera/Hemp) composite. In the rubber region beyond 100 °C the minimum molecular mobility and stress level affect the magnitude of the storage and loss modulus. The cole cole results evidence that the type of fiber and addition of filler affects the homogeneity of the hybrid composite.

In this study, blue-emitting carbon quantum dots (CQDs) have been directly synthesized via an ultrasonic method using starch soluble as the carbon source. The CQDs were modified by using γ-methacryloxy propyl trimethoxyl silane (KH570). The modified CQDs were then combined with silicone rubber (SR) through a hydrosilylation reaction to fabricate CQDs/SR composites. The results indicated that the average size of the as-prepared CQDs was approximately 2.6 nm, with a distribution between 1.0 and 4.0 nm. The CQDs modified by KH570 were well dispersed in the SR, which can effectively prevent the fluorescence quenching of the CQDs due to agglomeration. Remarkably, the as-prepared CQDs/SR composites emitting bright blue fluorescence have high transparency, great mechanical properties and good thermal stability, thereby facilitating enormous potential applications in a wide variety of fields such as optoelectronic devices and LEDs.

The present work investigates the usefulness of milled fly ash, prepared by 60 h mechanical milling of raw fly ash, for the application of brake friction composites. Two specimens were prepared by reinforcing 80 wt% of the raw and milled fly ash with 20 wt% of the phenolic resin. The influence of mechanical milling on the friction and wear performance of the developed raw fly ash composite (RFC) and the milled fly ash composite (MFC) specimens were investigated at varying sliding velocity from 2.6–10.4 ms⁻¹ under 50 N and 150 N using wear and friction monitoring apparatus. It was revealed from the surface morphology of the milled fly ash powder that the large size spherically shaped particles turned in to small size rough shaped particles after ball milling. The average particle size of the raw fly ash reduced from 85.69 μm to 14.61 μm and the specific surface area of the milled fly ash increased by 7.3 times that of the raw fly ash. The tribo-study showed that the average friction coefficient of MFC was found to be noticeably higher than the RFC at all the sliding conditions except at 7.8 ms⁻¹ and 150 N. The increase in sliding velocity increased the weight loss of RFC and MFC specimens at low and high loads. The friction performance of MFC was found encouraging but attention is needed towards decreasing the wear rate when using the milled fly ash for the development of brake friction composites.

The pine cone plant is a cellulosic material that is inexpensive and abundant in nature. It can be used as a reinforcing material in thermoplastic based composites. Pine cone plant has good mechanical properties and therefore allows it to be used as a filler material in composites. Alternative utilization from such agricultural pine cone powder in high density polyethylene (HDPE) composites can supply economic and environmental advantages. In this study, pine cone reinforced high density polyethylene (HDPE) composites were fabricated and their mechanical (i.e., tensile, compression and flexural properties) and low velocity impact behaviors were determined experimentally. To this end, collected pine cones were firstly cut into 1 cm pieces by using a knife and were pulverized by grinding in a ring mill. After that, two HDPE plates with dimensions of 350 × 350 × 1 mm were manufactured in the hot press. Then, various percentage amounts of powdered pine cones (5, 10, 15 and 20% wt) were added between these plates. Thereafter, pine cone reinforced HDPE composites were obtained under the same conditions. Mechanical properties and low velocity impact behaviors of the pine cone reinforced HDPE composites were determined at room temperature and findings were compared with each other. The parameters such as tensile and flexural strengths, compressive strength, elasticity and flexural modulus and energy absorption capacities of the composites were evaluated through various curves. According to obtained results, HDPE containing 10% pine cone powder showed the highest tensile strength, elasticity modulus and flexural strength. Low velocity impact test results exhibited that maximum contact force values of the reinforced HDPE with 5, 10 and 15% wt pine cone powder are higher than the neat HDPE at the impact energy levels ranging from 5 J to 25 J.

The polyvinyl alcohol (PVA) films doped with various wt% of yttrium nitrate salt were synthesized by standard solution casting technique in order to examine the functional electrical and optical properties. The degree of the crystalline structure that evaluated in the films were investigated by x-ray diffraction and Fourier transform infrared spectroscopy measurements. In addition, the surface images have been obtained via scanning electron microscopy (SEM). The optical parameters have been calculated from UV–visible-NIR transmittance spectroscopy. Also, the dielectric constant measurement and the DC resistance that are arisen in the PVA films with different wt% of Y³⁺-ions have been done. All the samples show semi-crystalline phases. The average size, of the cluster Y³⁺-ions in the SEM images, increase to 1.63 μm for PVA/37 wt% Y³⁺-sample. Therefore, the optical absorption of this sample is higher than the others. The value of the energy gap decrease from 5.11 eV to 4.47 eV for PVA/0.037 wt% Y³⁺ and PVA/37 wt% Y³⁺-samples, respectively. The nonlinear current—voltage behavior, at high applied voltage, of the polymeric films, is observed with different values of slope, which is a characteristic of the varistor materials. So, these films could be used in different applications like optoelectronic and varistor devices.

This study investigates the fracture behavior of the marine sandwich composite with a PVC foam core and face sheets of the glass fibre reinforced polymer fabricated by vacuum assisted resin infusion method. The strain energy release rate G_I values (SERR) was obtained by analytical and experimental methods. For testing mode I, Single Cantilever Beam (SCB) test configuration was distinguished in order to prevent crack kinking. The special test apparatus was designed and manufactured for this experimental study. The effects of core density and core thickness on the fracture behavior of the sandwich composites at different temperatures were examined. The effects of four different temperatures (0, 23, 40 and 60 °C) on two core densities (80 and 130 kg m⁻³) and three core thickness (15, 20 and 25 mm) were studied under the fracture behavior concept. Finite element model was used for modeling the structure. ANSYS 15 was utilized to simulate mode I delamination and mechanical properties of face sheets and PVC foam obtained experimentally were used in the model. The SERR value was calculated using the virtual crack closure technique (VCCT). Reasonably good results were obtained between analytical and numerical methods.

In automotive brake pad materials, the metal sulfides act as a solid lubricant at low and medium temperatures (80 °C–260 °C). The metal sulfides improve the fade resistance of brake pad material at elevated temperature cycles (above 260 °C). The purpose of this research work is to highlight the individual effect of the metal sulfides, namely Bismuth Sulfide (Bi₂S₃), Tin (IV) Sulfide (SnS₂) and Antimony trisulfide (Sb₂S₃) in the friction and wear behavior of the brake pad (BP) material formulation. The friction and wear performance of the developed brake pads were studied with the help of the chase friction tester using SAE J661a standard. The worn surface was characterized using Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscope (EDS). The thermal properties of metal sulfides were found out using differential scanning calorimetry (DSC). All the developed brake pads with different metal sulfides contributed to the friction stabilization at a particular temperature range. The sulfides influenced the formation of a tribo layer in all the brake pads. The friction performance of SnS₂-BP has been found to be comparatively better than Bi₂S₃ and Sb₂S₃-BPs. The wear performance of the Bi₂S₃-BP has been found to be moderately higher than other BPs.

Thermo-electro-mechanical instability of an incompressible electro-active polymer cylindrical shell subject to an inflation pressure under a thermo-electric field is analyzed in this paper based on the theory of nonlinear continuum mechanics. The deformations and stress distributions of the shell with different temperatures or voltages are presented through numerical computation. When the inflation pressure is larger than a certain critical value, the deformation curve of the shell may be non-monotonic. Energy comparison demonstrates that the deformation is unstable when the pressure is larger than the critical value and further increase in the pressure may lead to a sudden jump in the size of the shell. The critical wall thickness of the shell increases with increasing axial stretching while it decreases with increasing voltage or temperature. The critical pressure decreases with increasing voltage or temperature. In addition, the circumferential stress decreases with increasing radius while the axial stress increases with increasing radius. At the same time, the circumferential stress increases with increasing pressure while it decreases with increasing voltage or temperature. The axial stress always increases with increasing pressure, voltage or temperature.

Additive manufacturing technologies provide rapidly developing and promising solutions in many fields of healthcare. Traumatic upper limb injuries are among the most common conditions worldwide. In the case of a traumatic bone fractures it is crucial to provide immobilisation of the affected limb in the correct anatomical position to achieve the desirable healing process. Thus, splints and casts play an essential role in the healing and rehabilitation progress. 3D printing is a powerful tool in creating personalized biomedical devices, therefore, medical aids for the treatment of bone fractures are amongst the most promising fields of medical 3D printing. In medical care, the most extensively used area of additive manufacturing is Fused-Filament-Fabrication (FFF). In our study we have investigated two different unique PLA-CaCO₃ composites. To access the characteristics of the composites, dynamic and static mechanical stability tests were performed along with scanning electron microscopy for the structural analysis, and also manufactured splints with the help of 3D design and thermoforming methods. According to our results the new materials are potentially viable in clinical environment, but further laboratory and clinical investigations are necessary. Our aim is to continue the feasibility tests and establish the appropriate clinical trials.

This experiment addresses the effect of aluminium oxide nano powder in hybrid combinations of sisal/coir, sisal/banana and banana/coir. The alumina nano powder is green synthesized from the leaf of 'Muntingia Calabura' using 4:1 ratio of leaf extract and aluminum nitrate solution. Synthesized nano powder is used for upgrading mechanical, thermal and vibration damping applications of hybrid natural composites. Sisal/coir hybrid composites enhanced tensile, flexural and impact properties by 30.86%, 13.34% and 16.49% with addition of nano filler up to 3%. Sisal/banana hybrid composites add to the tensile, flexural and impact properties by 35.64%, 12.20% and 8.24%. Similarly banana/coir composites also showed the same path. DSC results revealed improvement in endothermic peak, initial temperature and endothermic enthalpy by nano substitution. Sisal/banana/coir combinations enhanced the natural frequency and damping values by nano filler in first three modes of vibration. In the same fiber percentage of 35 with varying nano powder content sisal/banana and sisal/coir has higher damping values than banana/coir due to smaller diameter of sisal (100–200 μm) than banana and coir. SEM images proved improvement in introducing nano powder into the natural composites, showing more of even distribution with reduced void content.

The present study reports the effective impregnation of silver nanoparticles (AgNPs) biosynthesized using Ocimum sanctum leaf extract onto conventional tissue paper for the inhibition of hospital borne pathogenic bacterial growth. The AgNPs biosynthesised using the leaf extract had face centered cubic lattice structure, nano scale dimensions, biocompatible coating of plant proteins and an absorbance maximum at 438 nm. Further, these nanoparticles were used to engineer tissue paper towels under conditions akin to room temperature. The presence of nanoparticles on the tissue paper filaments were confirmed using SEM analysis. Detailed analysis using XRD and FTIR indicated the presence of AgNPs on the paper fibres and the appreciable amounts of bio-active functional groups on the modified tissue paper when compared to the conventional ones. The bioactive layers aid the firm adherence of bacterial cell wall proteins and there after the silver particles extend their bactericidal action on the attached bacteria. The antibacterial activity of the nano-engineered tissue paper towels were tested against common gram positive and gram negative pathogens. Further, cytotoxicity evaluation using MTT assay revealed that the AgNPs coated paper towels does not pose any unintended adverse effects on fibroblast cell lines. These results highlight that biogenic AgNPs coated paper towels are cost effective, eco-friendly and wholesome alternative for the conventional paper towels and can be an effective sanitizing product for decreasing the risk of health associated infections.

Chronic recording and stimulation in central and peripheral nerves require both high mechanical and biological compatibility. The biocompatible CNT yarn has shown promising mechanical advantage as a novel neural electrode. In this study, we quantitatively characterized the mechanical properties of CNT yarn electrodes from the perspective of the flexural limit and the flexural rigidity. The traditional test configuration was remedied for ultrafine samples with efficient elimination of the bias caused by the manual operation. As compared to the traditional Platinum-Iridium (Pt-Ir) wire electrode, CNT yarns with the similar diameter had a much more promising flexural-limit property, and thus can overcome the severe electrode failure in chronic neural recording or stimulation.

The electrodeposition of thin chitosan membrane in freestanding microfluidic channel with capillary effect for biomolecule assembly of biosensor is investigated. A dry SU-8 sheet is used to fabricate freestanding fluidic microchannel by microelectromechanical systems (MEMS) technology. The hydrophobic surface of SU-8 microchannel transformed to hydrophilic surface by plasma treatment. The thin chitosan membrane is deposited on hydrophilic SU-8 microchannel by capillary effect, and miniaturization of sensor device is obtained. Membrane thickness of chitosan in freestanding channel can be controlled by concentration of chitosan solution and deposition time. The results show that thin chitosan membrane can be deposited by capillary effect in freestanding channel, and the deposited chitosan thin film shows great potential for immobilizing enzyme on the surface for compact biosensor device.

ZnO nanoparticles were synthesized by a precipitation-calcination method using a water extract of wood ash as a natural alkaline precipitating agent. The nanoparticles were characterized by x-ray diffractometry (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectroscopy (UV–vis-DRS), and thermal gravimetric analysis (TGA). The water extract of wood ash was used to minimize the effects of the toxic chemicals used in ZnO production. When a solution of Zn²⁺ ions was added to the water extract of wood ash, Zn₅(CO₃)₂(OH)₆ was co-precipitated with Zn₆Zn₂(OH)₁₃SO₄. After calcination at 900 °C for 1 h, the mixture had completely decomposed to produce the ZnO. The prepared ZnO nanoparticles showed photocatalytic activity through a degradation of the solutions of rhodamine B and reactive orange as the model pollutants under blacklight irradiation. Moreover, the prepared ZnO exhibited much higher photocatalytic activity than ZnO prepared from NaOH and commercial ZnO. According to the experimental results, the water extract of wood ash would be a potential natural alkaline precipitating agent to prepare ZnO nanoparticles in a green approach.

In this work, highly uniform Sb doped SnO₂ nanospheres with different Sb doping concentrations were prepared by a hydrothermal method. Compared with the pure SnO₂ material, the obtained SnO₂:Sb nanospheres exhibits significantly enhanced lithium storage performances in both of the initial capacity and the cycling stability, severed as anode materials for lithium-ion batteries. Among the SnO₂:Sb materials provided in this work, the SnO₂:Sb nanospheres with 6 at% of Sb dopants delivers a highest discharge capacity of 1575 mA h g⁻¹ (charge capacity of 914 mA h g⁻¹) at the first cycle and excellent cyclability (588 mA h g⁻¹ at 100th cycles), due to the reduced crystalline size and the improved electrical conductivity induced by Sb dopants.

Ge/SiGe-superlattices is a novel material that was designed and fabricated as a potential material for building thermoelectric generators. One possible advantage of using such material is its ability to integrate with the Si platform. The silicon platform is known to dominate the semiconductor industry due to its low cost and the mature technology. A major limitation of using superlattice structures to build Thermoelectric generators is that it requires a buffer layer to help minimize the strain due to lattice mismatch between the alternate combinations of elements that make up the superlattice structure. It therefore becomes difficult to grow the superlattice structure above a few micrometers. Therefore, this study evaluates the optimum geometrical height of Ge/SiGe-Superlattices that will yield improved performances in the TEG, using a combination of Finite Element modelling and experimental analyses.

In order to effectively solve environmental problems induced by organic pollutants, the MoS₂@ZnO heterostructure is successfully fabricated via a two-step hydrothermal method, in which the MoS₂ nanosheets grew on the surface of ZnO nanorods. The synthetic heterostructure is demonstrated to possess excellent photocatalytic activity in the degradation of methylene blue (MB) under ultraviolet (UV) and visible light irradiation. The corresponding photodegradation rate constant of MoS₂@ZnO heterostructure reaches up to 0.02075 min⁻¹ and 0.00916 min⁻¹, which are higher than that of pure ZnO (0.00514 min⁻¹ and 0.00048 min⁻¹) under the same reaction conditions. Obviously, compared with pure ZnO, the photocatalytic activity of the MoS₂@ZnO heterostructure has been significantly improved. This could be attributed to the increased specific surface area of photocatalyst and the formation of heterostructure between ZnO and MoS₂ after loading the MoS₂ on the surface of ZnO nanorods. Which help to provide more reaction sites for the adsorption of pollutant and improve the separation efficiency of photogenerated electron-hole pairs.

Rich husks are used as the raw material for preparation of silicon nanoparticles from an aluminothermic reduction process. The synthetic process is conducted on a low temperature condition, avoiding the large energy consumption resulting from high temperature operation course. The fabricated silicon has a porous structure with average particle size of approximately 30 nm. The unique structure triggers pronounced electrochemical behavior for Li alloy/de-alloy reaction. The material delivers an initial discharge and charge capacity of 3844.7 mAh g⁻¹ and 3144.4 mAh g⁻¹ at the current density of 100 mA g⁻¹. With the current density increasing to 6 A g⁻¹ and 8 A g⁻¹, the material shows a reversible capacity of 860.1 mAh g⁻¹ and 413.4 mAh g⁻¹, respectively. The low material fabrication cost and satisfactory electrochemical performance make the low temperature aluminothermic reduction to be a promising route for silicon fabrication for next-generation lithium-ion battery.

Two kinds of different separator Li-S batteries were prepared. One separator was one-side coated with MoS₂ towards anode, and the other separator was double-side coated with AC and MoS₂ (AC-MoS₂) towards cathode and anode respectively. These slurries of AC and MoS₂ have the high specific surface area and porous structure, moreover, MoS₂ has a highly 'catalyst' effect on sulfide conversion by virtue of its high electrochemical activity as well as strong binding energy with soluble lithium polysulfides. Assembled Li-S batteries with separators coated by AC-MoS₂, MoS₂ and uncoated separator show the initial discharged specific capacities of 1318 mAh g⁻¹ and 1257 mAh g⁻¹ and 957 mAh g⁻¹ respectively, and those of 719 mAh g⁻¹, 548 mAh g⁻¹ and 306 mAh g⁻¹ after 400 cycles at 0.2 C rate, with the coulombic efficiency remains over 98%. At the same time, the morphology of the separator coated by AC-MoS₂ after 200 cycles exhibits a homogeneous sulfur distribution. This coating technology on the separator provides a facile and efficient route to obtain the superior Li-S battery.

In this work, α-hemihydrate gypsum (α-HH) microrods were synthesized in large scale using flue gas desulfurization (FGD) gypsum as the raw materials in alcohol-salt system under normal pressure. The preparation conditions were investigated and optimized as follows: the concentration of Ca²⁺ was 2.9 mol·L⁻¹, the concentration of Mg²⁺ was 0.0315 mol·L⁻¹, the volume ratio of glycerol was 6%, the reaction time was 4 h, reaction temperature 92 °C, and the concentration of glucose 0.0370 mol·L⁻¹. The α-HH sample prepared under the as-optimized conditions was characterized by means of x-ray diffraction (XRD), energy dispersive spectrometer (EDS), differential scanning calorimeter (TG-DSC), scanning electron microscopy (SEM), fourier transform infrared (FT-IR) and transmission electron microscope (TEM). The results show that the sample was well developed α-HH microrods and performed uniform morphology with length up to approximately 100 μm and aspect ratio of 35:1. The formation mechanism of α-HH microrods was consistent with the growth mechanism of screw dislocation.

The adsorption uptake of synthetic mordenite-type zeolites with varying Si/Al ratio was investigated for Zn²⁺ ions in aqueous solution to determine the influence of Si/Al ratio in removing heavy metals. Synthetic mordenites were hydrothermally synthesized from gel solutions with Si/Al ratio of 10, 15 and 20 as denoted by samples SAR10, SAR15 and SAR20 respectively. The samples were characterized using XRD, SEM, XRF, and TG-DTA. The adsorption kinetic and thermodynamic behaviour of the synthetic mordenites were examined. From the kinetic study, the pseudo-second-order kinetic model best fit the kinetic data among other models (i.e. pseudo-first order and intraparticle-diffusion models). It was found that cation-exchange was the most dominant adsorption mechanism. Further, it was observed that the pH level significantly affects the sorption of Zn²⁺ ions. The uptake of crystalline mordenite increases more than threefold from 7.19 mg Zn²⁺/g at pH = 3 to 24.27 mg Zn²⁺/g at pH = 7 using feed solution of 100 mg Zn²⁺/L. With regards to the equilibrium data, the adsorption isotherm generated from Langmuir model fits better than that of Freundlich model. Accordingly, the theoretical maximum adsorption capacities of SAR10, SAR15 and SAR20 are 39.97, 48.90, 32.48 mg Zn²⁺/g respectively. The lower the Si/Al ratio, the higher the negative charge density of zeolites resulting to a higher cation exchange capacity (CEC). However, lower Si/Al ratio do not automatically mean higher maximum adsorption capacity of mordenites to heavy metal ions especially Zn²⁺, as demonstrated in this study.

Aqueous Li-ion capacitors (ALICs) have been extensively studied in recent years due to their safety, environmental friendliness and low availability. In this paper, we constructed an ALIC using carbon-coated lithium iron phosphate (LFP) as the positive electrode, activated reduced graphene oxide as the negative electrode and studied its electrochemical performance in 1 M Li₂SO₄ electrolyte. Here, coating of LFP particles is carried out by dopamine polymerization to form a uniform carbon layer on the surface of the particles, which increases the conductivity and cycle performance of LFP. The optimal ALIC can achieve 82.8 F g⁻¹ (based on the total mass of the positive and negative materials) at a current density of 0.2 A g⁻¹, and shows good cycling stability. The specific capacitance can still retain 73% of the initial value after 1000 charge and discharge cycles. The specific energy density can reach 11.5 Wh kg⁻¹ at a power density of 100 W kg⁻¹.

In this research, faujasite-type zeolite and iron oxide mixed catalyst were successfully synthesized to decrease the viscosity of heavy oil in an aquathermolysis reaction. Faujasite-type zeolite was synthesized using a microwaves-assisted thermal reaction and ultrasonic waves at different aging times, varied at 0, 7, 21 and 28 days. The iron oxide was synthesized by co-precipitation at low temperature. The XRD results showed that zeolite crystallization occurred after 5 days of aging time and achieved uniform crystallinity after 7, 14 and 28 days. The zeolite samples with 7 days of aging time had the smallest particle size (82.1 nm) and the largest specific surface area (304 m² g⁻¹). The FTIR spectrum of the heavy oil indicated a catalyst effect on the breakdown of the C–O, C–C and C–S hydrocarbon chains as well as an increase in transmittance peak in saturated C–H and C–H aromatic bonds. The catalytic test through the aquathermolysis showed that the catalyst with the highest efficiency (81.5%) was found among the zeolite samples with 7 days of aging time (FAU-7). Based on these results, the synthesized catalyst can be used to reduce the viscosity of heavy oils.

The surface of TiO₂ photoanode films for CdS/CdSe quantum dot-sensitized solar cells (QDSSCs) was modified through in situ hydrolysis and condensation of tetrabutyl titanate (TBT). Results showed that the surface area of the film increased after TBT modification, which was due mainly to the generation of small TBT generated TiO₂ nanocrystallites (TBT-TiO₂) adjoined the gaps in TiO₂ photoanode films, resulting in the increase of quantum dots (QDs) loading and light absorption. The TBT-TiO₂ also facilitated the electron transfer through the TiO₂ photoanode films. Owing to these synergistic effects, the short-circuit current density, open-circuit voltage, and resultant power conversion efficiency were significantly increased for the designed QDSSCs. And a power conversion efficiency of 4.76% was achieved under the TBT modification with an optimal concentration that was 28% greater than the bare device. Meanwhile, a comparison of the photovoltaic performance for TBT modified photoanode was made with traditional TiCl₄ modified one. It was found that the TBT modification on photoanode film contributed to higher light absorption capability and less charge recombination compared to TiCl₄ modification. The findings suggest TBT modification to be an effective approach to improve the performance of QDSSCs.

BiVO₄/BiOCl p-n junctioned photocatalysts were synthesized by surface replacement of pre-synthesized BiOCl with BiVO₄ via a hydrothermal route. BiVO₄ particles were decorated on the surface of BiOCl, the structures of which were favored of maximizing absorption of visible light. The photocatalytic activity of the herterojunctioned composites were evaluated by degradation of Rhodamine B (RhB) dye under visible light illumination. The results indicated that the composites exhibited superior efficiencies for RhB photodegradation in comparison with pure BiOCl, BiVO₄ and BiOCl/BiVO₄ with similar compositions. The 30% BiVO₄/BiOCl exhibited an optimal photocatalytic activity due to the combinative effects of large visible-light absorbance and formation of p-n junction. An effective built-in electric field was formed by the interface between p-type BiOCl and n-type BiVO₄, which promoted the efficient separation of photoinduced electron-hole pairs. Experiments on scavenging active intermediates demonstrated that the enhanced photoactivity was primarily attributed to the photogenerated holes of BiVO₄.

Electrochromics is the emerging technology for energy conservation and indoor climatic control through smart windows. In this study we are reporting four layer electrochromic device: ITO (400 nm)/commercially procured Nafion (183 μm)/WO₃ (44 nm to 200 nm)/ITO (400 nm). The active area (A) of the electrochromic devices are 3 cm². The tungsten oxide (WO₃) and ITO thin films have been deposited at room temperature (300 K) by reactive DC Magnetron sputtering. The sheet resistance of ITO is 20 Ω/◻. The 'as deposited' WO₃ films are amorphous and have high optical transmission (75%–85%) in the visible spectrum. The optical band gap decreases with increasing thickness of WO₃ thin films. The coloration efficiency (CE) of the electrochromic device increases with increasing thickness of the WO₃ layer. The CE for the device with WO₃ thickness 200 nm is 184 cm² C⁻¹: the highest reported so far for a hybrid electrochromic device. The increase in the CE with thickness has been explained (for the first time) by replacing the surface charge density (Q/A) with the volume charge density (Q/A*t) in the coloration efficiency formula derived from the Beer Lambert's law.

Graphitic carbon nitride (g-C₃N₄) is the most stable allotrope of carbon nitride with a conjugated, two-dimensional polymer of s-triazine, which is considered as a promising photocatalyst in sustainable chemistry. The low surface area and quantum efficiency and fast electron-hole recombination of g-C₃N₄ restrict its practical application. The formation of two-dimensional mesoporous structure and the construction of proper semiconductor composites are two approaches to promote the effective separation of photogenerated exciton and reduce the charge transfer resistance, which is beneficial to restrain the recombination of exciton and improve photocatalytic hydrogen performance. In this work, two-dimensional mesoporous g-C₃N₄ nanosheets (MCNS) coupled with nonstoichiometric Zn-Cu-In-S (ZCIS) nanocrystals were synthesized by a hydrothermal method. The constructed ZCIS/MCNS composites possessed highly photocatalytic hydrogen evolution performance under visible light irradiation without any noble metal cocatalysts. The EIS spectra and transient photocurrent responses corroborated ZCIS/MCNS had higher separation and transportation efficiency of photogenerated electron and hole. The incorporation of ZCIS into MCNS reduced the charge transfer resistance and enhanced the charge transfer efficiency. As the result, the photocatalytic hydrogen evolution rate of ZCIS/MCNS was higher than those of pure ZCIS and MCNS. 10-0.2ZCIS/MCNS showed a highest H₂ production rate of 12.3 μmol h⁻¹ over 100 mg photocatalyst without cocatalysts. This work supplied a feasible strategy to construct ZCIS/MCNS composites for the exploitation of solar energy.

Upgradation of the rank of lignite is mandatory for its effective utilization as a potential energy source. Microwave drying is being explored in the present work as an effective upgradation technique. The effects of operating variables such as sample mass, particle size and sample thickness were investigated. The work also attempts to compare the quality of lignite dried using conventional hot air and microwave drying utilizing characterization techniques such as SEM, FT-IR, BET. The SEM analysis demonstrate a considerable increase in number of pores, fractures and cracks in the upgraded lignite structure after microwave drying as compared to hot air drying. The FT-IR analysis indicate an overall reduction in the number of absorbance peaks and a significant reduction in the oxygen-containing functional groups with microwave drying as compared to hot air drying. The BET analysis reveal a 30 fold increase in specific surface area with microwave drying as compared to hot air drying. The major proportion of pores in the lignite after microwave drying were either mesopores or micropores, while that dried with conventional hot air were macropores. Microwave drying as compared with hot air drying is more effective having higher fixed carbon content. The moisture re-adsorption capacity weakened after microwave drying, while it increased with increase in particle size.

Fluorinated graphene oxide (FGO) with high fluorine content is a suitable alternative for superhydrophobic materials due to the existence of the C–F bond. In this paper, we demonstrate a facile, large-scale method for the preparation of FGO with higher oxygen content and fluorine content by adopting proper oxidants and solvent to oxidize commercial graphite fluoride (GIF) on the basis of modified Hummers' method. Chemical composition, morphology and hydrophobicity are characterized by FT-IR, XPS, TGA, TEM and contact angle (CA) test respectively. The results indicate that the increase in oxygen content is accompanied by a decrease in fluorine content and FGO fabricated by using KMnO₄ and the mixture of CH₃COOH: H₂SO₄ with a volume ratio of 3:1 owns higher O/C and F/C ratio and superhydrophobicity. The oxidation mechanism is speculated that fluorine atom detaches from GiF in a strong oxidation environment, resulting in the restoration of sp² C=C bond partly, and then sp² C=C bond could be oxidized by KMnO₄ or K₂FeO₄ efficiently. More oxygen groups broaden the applications of FGO as hydrophobic materials.

In this paper, high nitrogen austenitic stainless steel was welded by Nd:YAG -MAG hybrid welding technology, the microstructure and hardness distributions of welded joint of high nitrogen stainless steel in different heat input were studied. The investigation results showed that hybrid welding welded joint of high nitrogen steel cross-sectional is 'goblet' shape, the upper part is arc action area, and the lower part of the laser action area. The weld microstructure is consisted of austenite and a handful of ferrite. The hardness distribution of welded joint is not uniform, base metal hardness is the highest, the value is between 330–370 Hv, the hardness of weld is the lowest, the value is between 260–330 Hv. The hardness of welded joint decrease with increasing heat input. There is no soft zone in welded joint.

The frequency, chemical potential, hopping energy and temperature dependence of polarization in a graphene-topological-insulator heterostructure is investigated. The polarization is found to be sensitive to the graphene-topological-insulator hopping energy and chemical potential. Compared to hopping energy and chemical potential, temperature has a relatively small effect on the polarization which only slightly changes the peak value. The unique band structures of graphene-topological-insulator heterostructures give rise to dual polarization peaks. Furthermore, the position of the polarization peak that originates from the graphene bands is robust while the position of the other peak can be tuned by varying the hopping energy and chemical potential. From the polarization function two branches of plasma dispersion are observed due to the coupling of graphene and the surface states of topological insulators.

Graphene directly grown on dielectric substrates by chemical vapor deposition (CVD) or plasma-enhanced CVD (PECVD) usually suffers from poor crystalline quality and sometimes coexisting amorphous carbon. In this study, improved crystallinity of graphene is achieved by using a Faraday cage made of stainless steel mesh wire in PECVD. The Faraday cage can slow down the graphene growth rate significantly even at high temperature, which is essential for larger critical nucleus size, higher nucleation barrier, and better electrical properties. Raman spectrum investigation reveals better graphene quality grown with the Faraday cage. A hole mobility up to109 cm²V⁻¹ s⁻¹is obtained with a growth rate of 0.94 nm h⁻¹ at 650 °C.

In the present work, we consider the electronic properties of graphene with Kekule structure formed from two different C–C bonds in its hexagonal lattice. When the C–C bond alternation was introduced, a small band gap has been opened in the band structure of graphene and it increases linearly by a difference in the bond lengths δ. While the applied strain along the zigzag or armchair direction causes band gap to decrease rapidly to zero, the strain in the other directions can increase the band gap. Interestingly, when the graphene with Kekule structure is strained, its band gap is inversely proportional to the bond length difference δ. Opening a band gap in graphene due to bond alternation and strain can open up new applications in nanoelectronic devices.

Carbon fiber reinforced carbon composites (CFRC) and carbon fiber reinforced silicon carbide composites (CFRC/SiC) are materials of wide interest in the aerospace industry due mainly to their outstanding thermo-mechanical properties at high temperature. The control of the process of obtaining these composites, carried out non-destructive processes, such as x-ray tomography, are of great interest to the industry, since they are able to present not only information concerning density and porosity, but also 3D vision with identification of closed and open pores, as well as a precise location of these defects in the sample. In this study a CFRC/SiC hybrid matrix composite obtained by employing carbon-silicon reaction by direct impregnation of silicon powder and phenolic resin, followed by heat treatment at 1600 °C under inert atmosphere is monitored step by step, in its preparation stages, using x-ray computed tomography techniques compared with optical microscopy techniques to detect voids in its microstructure. The three methods presented were satisfactory for structural analysis of the steps of obtaining the CFRC/SiC composite, considering the resolution and sample preparation restrictions applied to each of them, under the working conditions described in this study.

In this study, a biosorbent prepared from Ziziphus spina-christi leaf was used in order to remove Cr(VI) from aqueous solution. To do this, Ziziphus spina-christi leaf firstly was heated for 3 h at 600 °C until it converted into charcoal powder. Afterward, its surface characteristics were evaluated using different analysis such as BET, SEM, FTIR, TEM, XRD, EDAX and MAP. Then, the effect of various parameters including pH, adsorbent dosage, contact time, temperature and initial ion concentration was examined on the Cr(VI) ion removal from aqueous solution and the optimum operating conditions to reach the maximum adsorption efficiency was obtained. The results showed that an optimum adsorption efficiency of 97.22% was obtained at a temperature of 60 °C, pH = 2, contact time of 55 min, the initial concentration of 10 mg l⁻¹ and adsorbent dosage of 5 g l⁻¹. Also, the adsorption process was fully studied in terms of equilibrium, kinetic and thermodynamic factors and it showed that the adsorption process followed the Langmuir and pseudo-second order kinetic models. In addition, the maximum adsorption capacity of Cr(VI) using Langmuir isotherm was 13.81 mg g⁻¹. Moreover, the results of the thermodynamics studies revealed that the removal of chromium ion by coaly Ziziphus spina-christi leaf powder is an endothermic process.

The present work attempts to regenerate the spent catalyst loaded with mercuric chloride utilizing microwave heating, followed by ultrasound augmented impregnation of Cu(NO₃)₂. The ultrasound augmented impregnation as compared to conventional impregnation has resulted in adsorption capacity higher by 12.5 mg g⁻¹. The impregnated Cu(NO₃)₂ inside the carbon porous matrix was converted to copper, copper oxide, and cuprous oxide after thermal treatment. The optimal microwave regeneration process conditions were identified to microwave power 500 W, roasting temperature 800 °C and roasting duration of 25 min. The CuO loaded samples prepared at optimal regeneration conditions exhibited a MB removal capacity is 122.5 mg g⁻¹. The physico-chemical properties of Cu-spent catalyst were examined by XRF, XRD, XPS, SEM, FTIR and N₂ adsorption. Additionally, the photocatalytic effectiveness of the Cu loaded porous matrix was tested based on the MB degradation efficiency. The ultrasound augmented impregnation was found to be far superior to conventional impregnation based on the ability to photocatalytically degrade MB.

Core/shell-structured nanodiamonds exhibit excellent adsorption and photocatalytic properties by annealing in an Ar atmosphere. Results show that core/shell-structured nanodiamond/onion-like carbon materials are obtained at high-temperature annealing (1400 °C–1500 °C) and possess a favorable visible light photocatalytic activity. Solutions with 10 and 100 mg L⁻¹ methyl orange can be nearly degraded completely within 30 min and 1 h, respectively, using nanodiamonds annealed at 1500 °C.

The structural and mechanical properties of the deltic, squaric and croconic cyclic oxocarbon acids were obtained using theoretical solid-state methods based in Density Functional Theory employing very demanding calculation parameters in order to yield realistic theoretical descriptions of these materials. The computed lattice parameters, bond distances, angles, and x-ray powder diffraction patterns of these materials were in excellent agreement with their experimental counterparts. The crystal structures of these materials were found to be mechanically stable since the calculated stiffness tensors satisfy the Born mechanical stability conditions. Furthermore, the values of the bulk modulus and their pressure derivatives, shear and Young moduli, Poisson ratio, ductility and hardness indices, as well as mechanical anisotropy measures of these materials were reported. A complete review of the literature concerning the negative Poisson ratio and negative linear compressibility phenomena is given together with the theoretical study of the mechanical behavior of cyclic oxocarbon acid materials. The deltic, squaric, and croconic acids in the solid state are highly anisotropic materials characterized by low hardness and relatively low bulk moduli. The three materials display small negative Poisson ratios. The croconic acid displays the phenomenon of negative linear compressibility for applied pressures larger than ∼0.4 GPa directed along the direction of minimum Poisson ratio and undergoes a pressure induced phase transition at applied pressures larger than ∼1.0 GPa.

Hydroxyl groups modified multi-walled carbon nanotubes (MWNTs-OH) were dispersed in N, N-dimethylformamide (DMF), water and chloroform, respectively. Each kind of dispersions were poured in 1-mm, 2-mm and 5-mm quartz cuvettes, respectively. The nonlinear optical (NLO) and optical limiting properties of the dispersions were studied using open-aperture Z-scan technique at 532 nm in nanosecond regime. Results show that thick cuvette or solvents with excellent thermodynamic parameters allows efficient replenishment of MWNTs-OH in the intensely irradiated volume, leading to excellent optical limiting properties arising from the well known nonlinear scattering, while thin cuvette or solvents with poor thermodynamic parameters allows inefficient replenishment of MWNTs-OH, which even leads to false appearance of 'saturable absorption-like' or 'nonlinear refraction-like' behavior due to the depletion of the sample. The different replenishment efficiency of the dispersions with the same solvent in cuvettes of different thickness can be attributed to the different influence of viscous force near the cuvette sidewalls. This influence should also be noted in other nanomaterials sharing similar NLO mechanism to carbon nanotubes dispersions during Z-scan experiments.

In this paper, we investigate the Raman and infra-red (IR) spectra of fully hydrogenated and halogenated graphene in a chair, boat and washboard conformations. The IR spectra of chair conformations have two peaks due to E_u and ${{\rm{A}}}_{2u}$ phonons, while their Raman spectra have four peaks due to E_g and ${{\rm{A}}}_{1g}$ phonons. There are low and high frequency in-plane E_g phonons and out-of-plane ${{\rm{A}}}_{1g}$ phonons which give rise to four peaks in the Raman spectra. The optimized structures of the boat and washboard conformations of CH have different point group symmetries. The optical phonons of these conformations of CH are either IR active or Raman active. However, the optimized structures of the boat and washboard conformations of CF and CCl are a bit twisted and have the same ${{\rm{C}}}_{2v}$(mm2) point group symmetries. In these conformations, there are four Raman active A₂ phonons and several other A₁, B₁ and B₂ phonons which are both Raman and IR active.

Here, we present a series of novel block copolymers (BCP) from bio-derived monomers, poly(lactic acid)-block- poly(2, 5-furandimethylene succinate) (PLA-b-PFS), in which the furan groups from PFS block can be crosslinked with bis(maleimido) triethylene glycol (M₂) through a Diels-Alder reaction. This dynamic crosslinking reaction leads to a network structure for enhancing the mechanical properties compared to their linear BCP analogous. Decreasing the crosslinking density leads to a decrease of glass transition temperature of BCPs and a transition from glassy to rubbery-like behavior at room temperature. This allows a wide tunablity of both elastic moduli and yields of the materials. For the lowest crosslinking density. the material exhibits an over 50% self-healing efficiency at room temperature after five days, attributed to the low T_g (15.2 °C) from the introduction of PFS block, allowing sufficient chain mobility for structure re-organization. Moreover, with the appropriate selection of crosslinking density (PLA-b-PFS/M₂ (6/1)), it also shows an excellent shape memory property with a high recovery rate of 96.3% and a fixity rate of 97.3%. The permanent shape can be rewriteable due to the reversibility of Diels-Alder reaction. With these advanced functionalities and ease in large-scale fabrication, the PLA-b-PFS/M₂ shows great promises for self-healing coatings or films with shape memory properties in a wide variety of applications such as packaging materials.

In the present work, agriculture waste based biocomposites were developed by reinforcing corn starch resin with various rice husk and walnut shell content of 5, 10 and 15 wt%. These fabricated biocomposites were investigated for physical, mechanical and thermal properties. It was found that the physical properties such as density and water absorption of the biocomposites remains in the range of 1.20–1.32 g cm⁻³ and 4.32%–8.68% respectively, while these properties decreased by the increase of rice husk and walnut shell content. The slower degradation rate of rice husk and walnut shell resulted in enhanced degradation period of the biocomposites. Thermogravimetric analysis revealed that the addition of increased rice husk and walnut shell content enhanced the thermal stability of the biocomposites. The evaluated mechanical (tensile strength, flexural strength, compressive strength, impact energy and hardness) properties were found to increase with the amount of rice husk and walnut shell content. The maximum tensile strength of 10.70 MPa, flexural strength of 19.60 MPa and impact energy of 0.362 J was observed for biocomposites with 15 wt% rice husk content. Similarly, the maximum compressive strength of 22.70 MPa and hardness of 21.31 Hv is obtained for biocomposites with 15 wt% walnut shell content. The rice husk based biocomposites gave better tensile strength, flexural strength, impact energy and thermal stability but resulted in lower hardness and compressive strength than the walnut shell based biocomposites. The biocomposites reinforced with walnut shell exhibit higher resistance to water absorption and biodegradability than those associated with rice husk. The results suggest that the developed biocomposites can be used as ecofriendly materials in lightweight applications.

This study reports a novel Hollow Soft Pneumatic Actuator (HOSE), which exhibits 4 degrees of freedom (DOFs). The design consists of a central hollow cylinder surrounded by four twisting symmetric chambers. By virtue of their spiral disposition, each chamber produces a diagonal force along the hollow internal cylinder composed of two components: one parallel to the Z axis and the other one to the plane X-Y. Both top and bottom sections of the actuator are reinforced to avoid deformation, essential for optimal function and dexterity of HOSE. Different movements of the actuator are produced by varying the activation combinations of the 4 chambers. They are constructed from thin walled (0.5 mm) Ecoflex 00–30 super soft silicon rubber, enabling HOSE to perform controlled movements with low pressure not exceeding 35 kPa. HOSE exhibits a maximal extension of 230% of its original length, bends up to i) ±90⁰ around X axis, ii) ±115⁰ around Y axis, and iii) twists around Z axis with a total range of ±35⁰. The paper describes the manufacturing process together with the actuator performance, reporting the range of motion along each DOF related to the internal pressure, volume versus forces and torques produced along each axis.

In this paper, based on phase gradient principle, a multi-function dual-layer reflective metasurface is proposed for linear-to-circular (LTC) polarization conversion, beam control and gain improvement. The rotation of reflected circularly polarized wave is switched by the electric field direction of incident linearly polarized waves. At the same time, the reflective circularly polarized wave emerges anomalous refraction (45.6°). The maximum gain of the reflected wave is increased by 3.6 dB (70%). The measured results and simulation results are in a reasonable agreement. The presented multi-function metasurface may offer unprecedented potentials for real-time, fast polarization conversion and beam control.

In the article, polarization and incident-angle independent metasurface absorber for X-band application has been proposed. Proposed absorber unit cell composed of a circular sector attached to a cross-shaped structure. The proposed absorber is symmetrical along the horizontal and vertical axis, which supports polarization angle insensitivity. Metasurface absorber shows the very good impedance matching with free space at 10.48 GHz along with 97% absorptivity. The full width at half maximum (FWHM) bandwidth is 480 MHz (10.24–10.72 GHz). In transverse electric and magnetic (TE and TM), modes the absorptivity of the proposed absorber is maintained above 90% up to 60° incidence angle. The absorber has an ultrathin thickness of 0.028λ_o, where λ_o is the wavelength of absorption peak. The absorption phenomenon is explained by normalized impedance, E-field distribution and surface current density. To analyze the metasurface properties effective permittivity, permeability and dispersion diagram has been demonstrated. The metasurface absorber has been fabricated and it shows the good accord between simulated and measured results.

A broadband metamaterial absorber was designed based on magnetic substrate and resistance rings. The absorber is composed of three layers coupling structures of resistance rings, magnetic absorbing layer and a metal plane. A full-wave electromagnetic simulation had been performed based on the finite-difference time-domain (FDTD) method. The optimized thickness of metamaterial absorber is 2 mm, two absorption picks at 7.58 GHz and 12.75 GHz are achieved. The absorption of this metamaterial absorber below −10 dB is from 6.76 GHz to 15.97 GHz. A strong electromagnetic resonance is excited by the resistance rings structure to improve the absorption in low-frequency. The absorption of MMA is originated from magnetic loss and dielectric loss in magnetic substrate. Finally, the sample of metamaterial absorber was fabricated and tested, the experimental results is basically consistent with the simulated results. The proposed metamaterial absorber has many advantages, such as thin thickness, broadband, and polarization insensitivity.

Graphene has some unique electric properties. Electric properties of graphene can be adjusted by chemical treatment or electrostatic treatment. Anti-parallel surface current density on cross-shaped sandwich structure and the cumulative charge on gap between unit cell of metamaterial absorber may be adjusted using graphene. The amount of surface current density and amount of cumulative charge on gap between unit cell may affect the magnetization and polarization, respectively. Tailoring magnetization may alter the absorber performance. In this work, we propose terahertz tunable metamaterial absorber by using graphene. The shifting of absorbance peak frequency altered from 0.77 THz to 0.65 THz while Fermi energy was increasing. The absorbance peak for 10 meV, 100 meV, 200 meV, 300 meV and 400 meV of Fermi energy are 0.72, 0.79, 0.87, 0.92 and 0.94, respectively. The alteration of electric properties of graphene yields alteration of absorbance peak and shifting of absorbance peak frequency.

Terahertz (THz) metamaterials' unit cell designs are similar in dimensions with single cell culture array. In this work, three-dimensional metamaterial designs are proposed to be integrated into a microfluidic chip to make use of this similarity to separate circulating tumor cells (CTCs) from red blood cells (RBCs) with physical structure and detect CTCs with terahertz spectroscopy. Using split ring resonator as the basic building block, five different designs demonstrating three design approaches are presented with fabrication method. The detection sensitivity of the designs was examined by simulation. A maximum of 38 GHz resonant frequency shift can be achieved when the chip captures one CTC at each capturing spot. This work will lay the ground work for future use of THz metamaterials to diagnose and treat cancer.

In this paper, a miniaturized patch antenna (MPA) with Zero Index Metamaterial (ZIM) as Superstrate at 518 MHz is designed and fabricated. The proposed method is utilized for retrieving the effective properties, i.e., impedance, refractive index, as well as the permittivity, and permeability of the unit cell. We have investigated the effect of distance between the antenna and the Superstrate on performance of the antenna. Moreover, the performance of the antenna is evaluated by both simulations and measurements. The results of our study have shown more directional and higher gain patch antennas. Also, a good agreement between the measured and the simulation values is found. It is demonstrated that the gain of antenna, having the ZIM Superstrate, is much higher compared to the one without the ZIM superstrate. Furthermore, the mean value of the gain for the proposed Metamaterial antenna (which is Superstrate-based) is considerably improved from −1.9 to 3.97 dBi comparing to the patch antenna alone. In fact, the directivity of the antenna is dramatically improved based on the zero refraction properties of the Metamaterial.

In this paper, a periodical array composed of patterned circular and elliptical disk graphene resonators on a silicon substrate spaced by a silicon dioxide dielectric layer is presented. Our research shows that the graphene arrays exhibit three absorption peaks of 16% at 26 μm, 30% at 31 μm and 34% at 45 μm. The absorption performance of our structure can be improved by changing the structural parameters of the graphene layer (we studied the different structural parts of the model, the size and proportion of their values respectively), dielectric multiplier and Fermi energy level. According to our conception, the proposed structure can be used in the far infrared spectrum detector, filter and sensor.

The mechanical, optical, thermoelectric and thermodynamic characteristics of Cesium based bromides are systematically studied using the most comprehensive DFT based Wien2k code for elucidating the energy renewable device applications. The mechanical, thermodynamic and structural stabilities of the studied perovskites are revealed in terms of Born mechanical stability criteria, enthalpy of formation and Goldschmidt's tolerance factor, respectively. The ductile/brittle nature, anisotropy, wave velocity and Debye temperatures are computed to illustrate the mechanical nature. The optical parameters have been found highly sensitive to the exhibited band gap lying within visible energy. The large thermoelectric efficiency has been found that is responsible to exhibit optimum values of the power factors and the thermal conductivity. Furthermore, the specific heat capacity, Hall coefficient, magnetic susceptibility and electron density are also described in detail. Hence, the studied perovskites showing band gap in visible region have been found suitable for commercial applications in Solar cell, optoelectronic and thermoelectric devices.

The two-dimensional WS₂ material with the capability of achieving high photoelectric characteristics has attracted more and more attention. However, it still suffers from the limited optical absorption and the lower photogenerated carrier lifetime. Here, we report a WS₂ photodetector decorated by the environment-friendly and stabilized graphene oxide quantum dots (GOQDs) as hole harvesting media. Through introducing GOQDs by a simple solution method, the photoelectric performances of the photodetector are improved efficiently. The photoresponsivity of the photodetector is increased to 12.5 mA W⁻¹, and the detectivity is also improved to about 2.01 × 10¹⁰ Jones. The enhanced photoresponsivity is attributed to the GOQDs-WS₂ heterostructure and photogating effect of GOQDs, which can promote the separation of the photogenerated electron-hole pairs and the hole carriers trapped in GOQDs, respectively. These reasons also extend the recombination time between them. This work may provide a new approach for preparing green and environment friendly photodetector with enhanced performance.

In the present work, we simulate the J-V characteristic of a solar cell combination to evaluate the efficiency in an optical splitter system. Two different transparent conductive oxides (TCO) were used as splitters (ITO and SnO₂:F). The spectral response of the TCOs was modeled according to Drude's theory, using different concentration values. Then, the J-V characteristics of the cells were simulated by SCAPS 1D, using the spectra obtained for each TCO by superimposing the spectral response on the solar spectrum. The results indicate that solar cells can achieve efficiencies in the system above 17% using ITO as splitter whit a positive gain for both solar cells.

We have performed first-principles calculations within density functional theory (DFT) to investigate the hardness, elastic, thermodynamic and electronic properties of metal nitrides compounds (XN₂; X = Pd, Pt) in pyrite structure, under high hydrostatic pressure. The calculated structural properties match with those previously reported experimental and theoretical data. The Vickers hardness of PdN₂ and PtN₂ compounds were calculated in 7.5 and 27.7 GPa, respectively. We also calculated the electronic properties of both compounds. The calculated electronic band structure of PtN₂ at either 0 GPa or 153 GPa reveals that this compound is an indirect semiconductor. The top of the valence band is located at M point, whereas the bottom of the conduction band at Λ point at zero pressure or at Σ point at 153 GPa. In the case of PdN₂, it was found a conductor-semiconductor transition at 104 GPa.

Effect of Fe doping on the structure, optical and thermoelectric properties of SrTi_0.8Sn_0.2O₃ sample has been investigated. The SrTi_0.8−xSn_0.2Fe_xO₃ (x = 0, 0.1, 0.3) samples are fabricated using solid-state synthesis route. It is observed that Fe doping helps in reducing the densification temperature of SrTi_0.8Sn_0.2O₃ during spark plasma sintering. Precipitation of Sn has been observed in SrTi_0.8−xSn_0.2Fe_xO₃ (x = 0, 0.1) samples while the SrTi_0.8−xSn_0.2Fe_xO₃ (x = 0.3) sample is of purely single cubic perovskite phase. All the samples consist of nanocrystalline grains and the grain size varies between 150 to 200 nm. Fourier transform infrared spectroscopy (FTIR) analysis reveals the distortion of TiO₆ octahedra due to the increase in Fe content. Raman spectroscopy analysis has shown that perovskite cubic structure is stable from room temperature to 873 K. From thermophysical measurements, it is shown that the Fermi band gap reduces from 2.87 to 0.66 eV with increase in Fe in the investigated samples. The Seebeck co-efficient is found to change the sign from n –type to p-type with the increase of Fe concentration in SrTi_0.8Sn_0.2O_3, which is an interesting observation to obtain p-type SrTiO₃ based thermoelectric materials. The optical and thermoelectric properties show that Fe doping improves the thermoelectric properties of SrTi_0.8Sn_0.2O₃ ceramics by altering the Seebeck co-efficient and thermal conductivity.

Vertically aligned Zinc Oxide nanowires (ZnO NWs) were grown on glass seeded substrates by the chemical bath deposition (CBD) method at a low temperature. Two parameters including temperature and atmosphere were varied while time and heating rate were kept constant. The field emission scanning electron microscopy images show that the ZnO NWs with a hexagonal cross section are grown perpendicular to the seeded glass substrates. The x-ray diffraction results reveal that all the ZnO NW arrays grow preferentially oriented along the c-axis in the direction of (002) plane with a hexagonal wurtzite structure. Photoluminescence measurements of the grown ZnO NWs on all samples exhibit a high ultraviolet (UV) peak intensity compared to a broad visible peak, which can be accounted for the formation of the high crystal quality ZnO NWs. Results show that the UV light emission is greatly enhanced by annealing the as-grown ZnO NWs in O₂ ambient. Moreover, transient response measurement reveals that the detectors exhibit a fast photoresponse time of fewer than 5 s. In this annealing case, the quantum efficiency of UV detection reaches about 15%. Finally, a qualified metal-semiconductor-metal (MSM) ZnO photodetector was prepared from the annealed as-grown sample in the pure O₂ ambient.

Narrow bandgap and high polarization are crucial for improving the photovoltaic properties of ferroelectric photovoltaic materials. In this work, bandgaps of tetragonal BiFeO₃ (t-BiFeO₃) with different magnetic orders are investigated using first-principles calculations. The results show that when the G-type antiferromagnetic order converts to ferromagnetic order, the bandgap of t-BiFeO₃ decreases from 1.530 eV to 1.037 eV and simultaneously the crystal still possesses large polarization (1.600 C m⁻²). Compared to C-type/G-type t-BiFeO₃, the bandgap narrowing of A-type/FM are originated from the downward shift of Fe 3d e_g antibonding states and the upward shift of O_b 2p states due to the ionicity increasing of Fe and O_b. This work provides an insight into how to improve the photovoltaic properties by tailoring the bandgap of the t-BiFeO₃ ferroelectric materials.

Cadmium sulphide (CdS) and Cu doped CdS film were deposited onto commercially available FTO glass substrate by the hydrothermal assisted chemical bath deposition (HACBD). The effect of doping on the properties of CdS films were investigated. Optical, morphological, structural and photoluminescence properties of deposited films were investigated using UV–vis spectroscopy, SEM, FTIR, x-ray diffraction and photoluminescence spectroscopy (PL). Lower value of the bandgap energy was observed for the Cu doped CdS films as compared to those of the undoped CdS films. XRD patterns revealed a cubic and hexagonal crystal structure phase with (1 1 1) and (0 0 2) as the preferential orientation having an average crystallite size of 18 nm. SEM images revealed a change in the morphology of CdS and Cu-CdS thin films from spherical to disclike structures. PL spectra showed strong emission peak in visible region for both doped and undoped films. The associated chemical bonds were investigated using FTIR spectroscopy.

We report a detailed numerical analysis of the optoelectronic characteristics of the indium composition on the device performance. The analysis includes discussion of the band-bending, built-in field, carrier confinement and emission spectra. The quantum well tilts strongly with increasing composition of indium. In addition, as the indium concentration increases in the active region, the spontaneous emission decreases and its full width at half maximum increases gradually.

In this work, we develop a simple and low-cost strategy toward the one-pot synthesis of reduced graphene oxide (rGO) capped copper sulfide (CuS) nanocomposite through an obvious redox transformation reaction between Cu and graphene oxide (GO) without any additive. The prepared CuS and rGO capped CuS nanocomposite have been characterized by various physicochemical techniques for the observation of shape, morphology, and structure. It reveals the average size of the synthesized samples in the range of 10–30 nm with the hexagonal structure. The UV–vis absorption spectra exposed the strong absorption peak of CuS and rGO capped CuS composites in the range of NIR region was observed. The synthesized samples displayed high dielectric constant and electrical conductivity in a wide range of frequency (10²–10⁶ Hz). The effect of temperature on the electrical conductivity of the synthesized rGO capped CuS nanocomposite was also investigated. The excellent electrical conductivity performance is ascribed to the synergistic effect between CuS and rGO. As the temperature increases, the maximum electrical conductivity of rGO capped CuS composite was exponentially increased at high temperature. The synthesized composite with a high dielectric constant and electrical conductivity is a promising material in high capacitance, and further, it is used as electrode materials for supercapacitors and energy storage applications.

In this paper, Ce-BiOI was innovatively prepared by a facile hydrothermal method followed by Ce-BiOI immobilizing on luffa via co-precipitation process with assistant of ionic liquid. The Ce-BiOI/luffa photocatalyst were measured by different characterization techniques including x-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectrometry, photoluminescence (PL) spectra and UV–vis diffuse reflectance spectroscopy (DRS). Photocatalytic performance of Ce-BiOI/luffa was investigated by degradation of Azocarmine G (ACG) under visible light irradiating. 99.9% of ACG was degraded by Ce-BiOI/luffa photocatalyst after 200 min of visible light irradiating. At the same time, photocatalytic degradating efficiency remained at 98.5% after six-cycles tests. Enhancements of photocatalytic activity were believed to relate with the strong visible light adsorption and efficient charge separation of photogenerated electron-hole pairs. To fathom the optimum condition, influences of Ce-BiOI/luffa loading ratio and initial ACG concentration was studied in this work. Furthermore, reactive species trapping experiments were carried out to verify that holes (h⁺) and superoxide radical anions (·O₂⁻) were the main reactive species in ACG decomposition.

High-quality BiTeCl microcrystals are grown by the physical vapor transport (PVT) method without using a foreign transport agent. The plate-like microcrystals with a developed (0001) surface are up to ∼500 μm in diameter. The grown crystal phase composition was identified by the x-ray single crystal structure analysis in space group P6₃mc: a = 4.2475(6) Å, c = 12.409(2) Ǻ, Z = 2 (R = 0.0343). The BiTeCl microcrystal phase purity was verified by Raman microspectrometry under excitation at λ = 632.8 and 532.1 nm.

Using first-principles density functional theory, the modulated electronic and optical properties of TiO₂ with Pt/Ag substitutional dopants with varying concentration are investigated. Our calculations reveal the significant decreasing trend in the band gap of TiO₂ while increasing the Pt (direct band gap) and Ag (indirect band gap) impurity concentration from 4.17% to 8.33% to 12.5%. The spin-polarized density of states reveal strong hybridization between the impurity bands with Ti-(3d) and O-(2p) bands near the Fermi level. The charge transfer mechanism depicts the delocalized electron cloud forming a strong bonding between the dopants (Pt/Ag) and oxygen of TiO₂. Moreover, the absorption spectra of the Pt doped TiO₂ structures have a broad peak at the visible range of energy spectrum with maximum absorption up to 0.7 × 10⁻⁵ cm⁻¹. The calculated reflectivity, energy loss function and extinction coefficient shows the enhanced optical properties of doped TiO₂ compared to its pristine form. The obtained results predict the way to tailor the optical properties of Pt/Ag-doped TiO₂ as an efficient photocatalyst in the visible region.

Dielectric relaxation at higher frequencies with dc conductivity contribution is observed in PVA/PVP hydrogel synthesized Nano-crystalline Cerium oxide (CeO₂), which is a typical oxygen ion conductor. The material is characterized using XRD, FTIR, Raman spectroscopy, SEM, TEM, UV-Vis and Impedance spectroscopy. Impedance spectroscopic data of the material are studied with combined Cole-Cole type conduction and dielectric relaxations and the results revealed that the material possesses two types of dipoles, pinned dipole and free dipole. The electrical parameters extracted from the analysis are found to be independent of ac data representations. The dc conductivity σ_c, conduction relaxation time τ_c and dielectric relaxation time τ_d show Arrhenius behavior. Conduction process follows Barton–Nakajima–Namikawa (BNN) relation and dielectric process follows fractional Debye–Stokes–Einstein (DSE) equation. Time-temperature scaling of complex impedance data suggests that the conduction mechanism is slightly temperature dependent. Intrinsic defects created in the material and hopping of charge carriers generate a combined relaxation in the material.

The effect of dipping time on the structural, optical and electrical properties of Sb₂S₃ film deposited on the glass and silicon substrates by chemical bath deposition technique was studied. The values of the optical energy gap determined from optical absorption were in the range 2–2.5 eV indicating good tunability of the film energy gap in the visible region. X-ray diffraction XRD result confirms that the all deposited films are crystalline in nature with orthorhombic phase and the reflection peak intensity was found to be decreased as dipping time increase. Scanning electron microscope SEM investigation reveals that the film morphology and grain size are depending on the dipping time. The film deposited at 3 min reveals a porous structure and spherical microcrystalline particles distributed over plate-like crystallites structure was observed for a film deposited at a longer time. The elemental analysis of the film as a function of dipping time was investigated using energy dispersive x-ray EDX. The Hall mobility of the film has increased from 2 to 4.75 cm²V⁻¹ s⁻¹ as dipping time increased from 3 to 9 min. It was found that the dipping time playing a vital role in controlling the figures of merit of n-Sb₂S₃/p-Si heterojunction photodetectors namely dark and illuminated current-voltage, responsivity and specific detectivity. Spectral responsivity findings show that the photodetectors have two peaks of response located at 500 and 700 nm. Energy band diagram of the Sb₂S₃/Si heterojunction was constructed.

The existences of topological nodal-line states and topological Dirac surface states in the non-centrosymmetric superconductor PbTaSe₂ have been demonstrated by some recent experiments combining with first-principles simulations. Here, we predict by means of the first-principles calculations that PbTa₂Se is also a phonon-mediated superconductor. The superconducting temperature T_c is estimated to be ∼7 K, greatly larger than that of PbTaSe₂ (T_c ∼ 3.8 K). The main contribution to the electron-phonon coupling and superconductivity is from the in-plane vibrations of Ta atoms. After including the spin–orbit coupling, a continuous energy gap in the whole Brillouin-zone is opened.

The superconducting properties of (Mg_0.8Zn_0.2Fe₂O₄)_x/Cu_0.5Tl_0.5–1223 matrix for concentrations (x = 0.0, 0.5, 1.0, 1.5 wt%) were synthesized by two-step solid state reaction method and analyzed by different characterization techniques. The magnetic Mg_0.8Zn_0.2Fe₂O₄ nanoparticles were synthesized by sol-gel technique separately and later inserted in CuTl-1223 superconducting matrix to obtain final product. The Mg_0.8Zn_0.2Fe₂O₄ nanoparticles were separately characterized by various techniques such as x-ray Diffraction, Scanning Electron Microscopy (SEM), Energy Dispersive x-ray Spectroscopy (EDX) and Vibrating Sample Magnetometer (VSM). The superconducting (Mg_0.8Zn_0.2Fe₂O₄)_x/CuTl-1223 composite samples (x = 0 ∼ 1.5 wt%) were also characterized by various available characterization techniques. The XRD analysis showed spinel cubic structures of magnetic nanoparticles and tetragonal structure of superconducting composites. The XRD spectra revealed that the tetragonal structure of CuTl-1223 superconducting phase was not disturbed after the inclusion of magnetic Mg_0.8Zn_0.2Fe₂O₄ nanoparticles. The behavior of Mg_0.8Zn_0.2Fe₂O₄ was found ferromagnetic in nature during an applied magnetic field. The FTIR analysis exhibited results that Mg_0.8Zn_0.2Fe₂O₄ nanoparticles are settled at grain-boundaries and there is no major variation in oxygen modes. The value of critical temperature T_c(0) reduce with increase in magnetic nanoparticles content. The reduction in activation energy is also noticed with greater addition of magnetic nanoparticles. The overall suppression of critical parameters and activation energy values is due to the net spin of ferromagnetic natured Mg_0.8Zn_0.2Fe₂O₄ nanoparticles, which may scatter charge carriers and increase dissipation energy and ultimately result in pair breaking and resistive broadening to deteriorate flux pinning ability of the superconducting composite matrices.

Here, we report self flux single crystal growth of FeTe_1−xSe_x (0.00 ≤ x ≤ 0.50) series via solid state reaction route; the resulted crystals as seen are shiny. X-Ray diffraction (XRD) performed on the surface of crystals elucidated the growth in (00l) plane, i.e. orientation in c-direction only. Scanning electron microscopy (SEM) images showed slab like morphology and EDX (Energy dispersive x-ray analyzer) confirmed that the crystals are closed to their designed compositions. Rietveld analysis of the XRD patterns of crushed crystal powders showed that the cell parameters decrease with Se content increase. Coupled magnetic/structural phase transition temperature, seen as a step in resistivity for the lower Se concentration i.e. 0.00 ≤ x ≤ 0.07, decreases from around 65 K for x = 0.0 to 50 K for x = 0.07 and it is not detected for higher x values. Superconductivity is observed by resistivity measurement for higher Se concentration i.e. 0.07 ≤ x ≤ 0.50, up to a maximum temperature of 14 K at x = 0.50. Thermally Activated Flux Flow (TAFF) analysis based on high field transport measurements in superconducting region done for x = 0.20 crystal exhibited activated flux energy to be decreasing from 12 meV (0.5Tesla) to 4.6 meV (14Tesla). Raman spectroscopy at room temperature of synthesized samples exhibits all the allowed phonon modes with slight shift to higher frequency with Se content. Mossbauer spectra of FeTe_1−xSe_x crystals series were recorded at 300 and 5 K. At 5 K, the average hyperfine field decreases systematically with Se content increase from 10.6 to 6.1Tesla for x = 0.0 to x = 0.20 samples. This indicates a possibility of co-existing magnetism and superconductivity in 0.07 ≤ x ≤ 0.20 crystals. For x = 0.50 sample, no hyperfine field related to magnetic ordering is seen. Based on above results, detailed phase diagram of the FeTe_1−xSe_x (0.00 ≤ x ≤ 0.50) compounds is defined in the present study.

Ferrofluids were prepared by adding γ-Fe₂O₃ nanoparticles, which was synthesized by co-precipitation method, into a blend of 1:1 ratio of mineral/sunflower oil. The structure, morphology and crystal size of nanoparticles were analyzed by FTIR, SEM, XRD and nanosizer. The crystal size of the nanoparticles was 12 nm calculated by using Debye–Scherer equation. The results via nanosizer showed that the mean diameter of nanoparticles was ∼59 nm at 100% intensity. The viscosity and thermal conductivity of the mineral oil, sunflower oil and different ratios of mineral/sunflower oil mixtures were investigated. Mineral oil has high thermal conductivity; however it requires high energy consumption for circulation due to its high viscosity. Although the viscosity of sunflower oil is low, its thermal conductivity is not sufficient for heat transfer applications. The results showed that 1:1 ratio of mineral/sunflower oil has a practical viscosity with low thermal conductivity. The addition of the synthesized γ-Fe₂O₃ nanoparticles into the mixture resulted in obtaining a ferrofluid with higher thermal conductivity. An average enhancement of 51% in the thermal conductivity of ferrofluid at 1.5 (w/v)% concentrations of γ-Fe₂O₃ nanoparticles was achieved as compared to the 1:1 ratio of mineral/sunflower oil. This ferrofluid may have practical applications in computer appliances, bearings, transducers, coolant, shielding and others.

Mechanically toughened electromagnetic shielding composite material was prepared with MWCNTs and Iron(III) oxide nano particles. The principal aim of this research work is explicating the advantage of magnetic particle addition along with conductive MWCNTs in EMW shielding. The kenaf fibre, MWCNTs and Iron(III) oxide particles were surface-treated by APTMS for effective dispersion and adhesion on matrix medium. The EM wave shielding composites were prepared using hand layup method. The mechanical results shows addition of kenaf fibre increased the tensile, flexural and impact properties. Similarly additions of MWCNTs and iron(III) oxide particles increased the electrical permittivity and magnetic permeability of epoxy matrix. The hysteresis graphs showed improved magnetization and retentivity in epoxy composites. The maximum EM wave shielding effectiveness of 82.5% (14.5 dB) was observed for composite designation 'E' in J band microwave frequency. The SEM images showed improved adhesion of fibre and dispersion of particle in epoxy matrix.

Four non-stoichiometric nano nickle ferrite samples have molar Ni contents of 0.23, 0.41, 0.62 and 0.82, as they were checked by atomic absorption spectroscopy, were synthesized by precipitation method. The synthesized compositions were checked by x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). All particles showed the spherical shape and inverse spinel structure with average sizes from 21 nm to 29 nm. The maximum magnetization saturation of 4.3 emu g⁻¹ was at Ni content of 0.62. The zero field cooling and field cooling measurement exhibited that the particles had superparamagnetic properties of blocking temperature near room temperature. The synthesized compositions were impeded within an equal amount of epoxy matrix. Different magnetic parameters were measured by conducting the shortcut broadband ferromagnetic resonance (BFMR) tests. The compositions showed a linear proportion between magnetic field and microwave resonance frequency in range 1.5–26.5 GHz. The maximum g-factor with low effective magnetization was Ni content of 0.62. The minimum damping constant was for composition for Ni content 0.41, and generally increasing Ni concentration increases damping factor. The inverse of the quality factor was reduced with frequency increasing.

In this work, a new concept of dynamic granular arrays was proposed based on magnetically controlled particles. Method of external rotating magnetic field (ERMF), based on a dipole interaction of magnetic spherical Fe₃O₄ particles in highly ordered volume arrays is proposed and a design for its practical implementation is developed. The paper also presents a method for the formation of flat microspherical particles arrays using a dipole magnetic field of a given geometric shape. Reflection spectra of electromagnetic radiation from a volume dense packed array of Fe₃O₄ particles with thicknesses of 3 and 6 mm, and a flat particles array with a set of 15 and 30 layers, as well as frequency characteristics of attenuation of electromagnetic radiation of the claimed materials in the frequency range from 8 to 12.5 GHz obtained. Presented method and the installation have the prospect of being used in the processes of making composite materials for electromagnetic radiation protection using a wide range of materials of micro and nanoparticles.

The bending vibration of the composite cantilever beam with magnetostrictive layer is investigated to simulate the dynamic response of a magnetostrictive actuator. Based on Timoshenko beam theory and the standard square nonlinear constitutive relations of magnetostrictive materials, new governing equations for deflection and two rotations in two layers of beam were obtained by Hamilton's principle. The analytic solutions of the problem are found by the means of the space-time variable separation technique and the general solution theory for system of ordinary differential equations. The numeric verification examples illustrates validity of both the new mathematical model and the presented solutions. Furthermore, the influence of the geometric and material parameters on natural frequencies of the beam is examined in details. The responses of deflection and stress in the action of excited magnetic field is analysed, and it confirms in theorical that the behavior of frequency multiplying observed from the reported experiments in the literatures is an inherent dynamic characteristic for nonlinearily magnetostrictive actuator. The further study indicates that such behavior could be suppressed by increasing the bias magnetic field. In addition, the magnetic flux density caused by effect of magnet-mechanical coupling are calculated for the magnetostrictive cantilever beam. This work contributes to understand the dynamic characteristics of magnetostrictive composite cantilever actuator. The developed model can be used to guide the design of the magnetostrictive composite cantilever actuator for promising applications in MEMS.

A floating opal placed on a certain liquid will cause the liquid to climb through the opal gaps, fill all its pores, and stop almost of its upper surface without covering it. A drop of solution with a surface tension much lower than that of water, deposited on a hydrophilic substrate near an opal, rapidly spread over a large surface forming a film which will surround the opal and infiltrate it from the side without covering it. High quality, skin-free, inverse opals can be synthesized by rise and side infiltration of solution in opals. The overlayer absence leads to the fabrication of mechanically robust, crack-free, completely filled photonic crystals which preserve the long rage order of initial opals. Inverse opals of sodium silicate were synthesized starting from polystyrene nanospheres self-assembled through hanging drop technique followed by their rise and side infiltration, casting, and template removal. Crystalline material inverse opals such as glycine, sodium chloride, and sulfur were also synthesized.

Li_1.0Nb_0.6Ti_0.5O₃:3 wt% Eu³⁺ red phosphor was synthesized by sol-gel method. The influences of the pH value and the citric acid(CA)/metal cations(M) ratio on the luminescent properties of the samples were discussed. The properties of the samples were characterized by x-ray diffraction (XRD) and photoluminescence spectroscopy, respectively. The results showed that the samples were consist of 'M- phase'. Under the 466 nm excitation, the orange emission at 592 nm and the red emission at 612 nm could be observed. The emission intensity increased with the increasing of pH value firstly and then decreased. The optimum pH value was 5.5. Moreover, the emission intensity decreased with the increasing of CA/M ratio. The relatively high emission intensity of the sample could be obtained when the CA/M was 3:1. Emission spectra and CIE coordinate of Li_1.0Nb_0.6Ti_0.5O₃:3 wt% Eu³⁺ were superior to commercial red phosphor Y₂O₃:Eu³⁺, which showed the red phosphor could have potential application in the White-LED field.

Absorption (K), reflection (R) and wavelength modulated transmission (ΔT/Δλ) spectra in SnS₂ crystals of hexagonal phase (space group P6₃/mmc) were investigated in temperature interval from 300 to 10 K. It was established that indirect band gap (${{{\boldsymbol{E}}}_{{\boldsymbol{g}}}}^{{\boldsymbol{ind}}}$ - 2.403 eV) is due to unpolarized indirect transitions between Γ and M points of Brillouin zone. A minimal direct band gap (${{{\boldsymbol{E}}}_{{\boldsymbol{g}}}}^{{\boldsymbol{dir}}}$ - 2.623 eV) in E∣∣b polarization is formed by direct allowed transitions and in E⊥b polarization (2.698 eV) by forbidden transitions in Γ point of Brillouin zone. A magnitude of refractive index (n) changes from 3 to 4 and has a maximum at 2.6 eV. Optical functions (n, k, ε₁ and ε₂) in energy region E > E_g (3–6.5 eV) were calculated from measured reflection spectra by Kramers-Kronig analysis. Features observed in reflection and optical function spectra were assigned to electron transitions. This electron transitions were localized in framework of theoretically calculated band structure.

A composite compound (CC) has been developed by the physical mixing of two coordination compounds(1,10-Phenanthroline)tris[4,4,4-trifluoro-1-(2-thienyl)-1,3butanedionato]europium (III) [abbreviated as Eu(TTA)₃Phen or ETP] and (1,10-Phenanthroline)tris[2-acetoxybenzoate]terbium(III) [abbreviated Tb(ASA)₃Phen or TAP]. Strong photo-physical properties of CC have been used for its study in different liquid medium and in PVA polymer matrix also. The studies of optical as well as structural properties of composite material have been carried out to observe the nature of interaction, energy transfer and migration of energies. The Fourier Transform Infrared (FTIR) spectra of CC show no new bond formation at atomic level and hence both ETP and TAP are entangled to each other by weak interacting forces. The photoluminescence (PL) emission of the Eu³⁺ ions enhance while of the Tb³⁺ ions decreases in the CC, indicating migration of energy from Tb³⁺ to Eu³⁺ ion. The effect of medium on the optical properties of this composite material has been investigated in detail. The excitation, emission as well as decay profiles of the composite material has been carried out in polar (ethanol), non-polar (Chloroform) as well as in polymer matrix {Poly-vinyl alcohol (PVA) matrix}. The reason behind the different shape and intensity in excitation and emission spectra of the composite material in different medium has been discussed. That concludes maximum fluorescence intensity in PVA matrix and least in polar solvents. In last stage, the plasmonic silver nanoparticles (AgNPs) have been introduced to further enhance the emission intensity in PVA matrix.

In this article, we present the results of the experimental work on the impact of shock waves on optical properties of benzyl crystalline material. Test material of benzil crystal is grown along [100] plane by Sankaranarayana — Ramasamy method. In the present work, the functional shock waves of Mach number 1.7 are generated from pressure driven shock tube. The optical properties of test material are investigated by UV-Visible spectrometer over the range between 200 and 800 nm. The observed results show that the intensity of the absorption spectrum is inversely proportional to the number of exposed shock waves. The direct and indirect optical band gap energy (Eg) and Urbach tail energy (Ug) are determined from the optical absorption spectrum for pre and post shock wave loaded condition and found that shock wave loaded test crystal has high band gap energy. The optical constants namely extinction coefficient, real and imaginary parts of the dielectric constant, skin depth, optical density, optical conductivity and electrical conductivity are investigated and the obtained results are compared with post shock wave loaded benzil crystal with the incident light possessing wavelength at 700 nm. The results are found to be very impressive for the shock wave recovery experiments that are to be clearly discussed.

The samples of LiMgPO₄ were synthesized by the solid state reaction and melting methods. The EPR spectra obtained at 300 K and 115 K are indicative of the existence of charged defects in LiMgPO₄. The main imperfections are identified as a radical CO⁻₃ (g = 2) and a singly charged oxygen vacancy (g₁ = 2.45, g₂ = 2.20, g₃ = 2.00). The presence of carbon-containing groups is proved by Raman spectroscopy. The assumption is made that the defects are located mainly on the surface of the grains. Thermoluminescent characteristics of LiMgPO₄ annealed in atmospheres with different p_O2 demonstrate that the surface defects impair the efficiency of LiMgPO₄ as a dosimetric material.

Organic crystal of L-Glutaminium p-Toluenesulfonate (LGPT) was grown in unidirectional by Sankaranarayanan and Ramasamy (SR) method. The grown crystal belongs to monoclinic crystal system with noncentrosymmetric space group P2₁. High resolution XRD confirms crystalline perfection of the grown crystal. Optical transmission shows that unidirectional grown crystal has higher transmittance and the lower cut-off wavelength is 290 nm. The emission wavelength of grown crystal is 410 nm and emission region is confirmed by luminescence spectra. The laser damage threshold value of unidirectional crystal has increased by 0.3 GW cm⁻². The grown LGPT crystals belong to hard material category and it confirms the normal indentation size effect. The grown LGPT crystal is thermally stable upto 165 °C and decomposition of the molecules were elucidated by using TGA and DSC. Powder second harmonic generation measurement confirms the efficiency of the grown LGPT crystal is 0.8 times that of KDP.

The temperature dependent near band edge emission of LPE grown GaSbBi is studied using photoluminescence technique. A two oscillator model is used to obtain the relevant parameters that explain the temperature dependence of band gap more adequately in cryogenic region as compared to the information obtained through the conventional 'Varshni' model. The two oscillator model also provides some valuable information on the phonon dispersion co-efficient in GaSb and GaSbBi and its behavior vis-à-vis the bismuth content in the material. Calculations show that the relative contribution of the high energy LA phonon branch increases with increase in Bi concentration and dominate the temperature dependence of band gap. By considering the energy gap as Gibbs free energy of electron and hole pair formation, approximate analytical expressions are derived for the entropy and the enthalpy of the formation process. The entropy of formation of electron-hole pairs is found to decrease with Bi content in GaSbBi indicating an increase in ordering and a decrease of electron- phonon interaction which might explain the reduced temperature dependence of band gap of some III-V-bismides.

This paper mainly studied the atomic migration in molten Sn-58Bi solder joints induced by the thermo-electric coupling effect. Individual electromigration (EM), individual thermomigration (TM) and the coupling EM with TM were conducted to confirm the prominent diffusing species and its migrating behaviors in the solder, respectively. During EM, step loading with different current densities was designed to verify that there existed a transition on the prominent diffusing species when Sn-58Bi solder melted. Cu atoms from the cathode were driven towards the anode to produce thicker Cu₆Sn₅ intermetallic compound (IMC) layer at the anode interface under current stressing. During TM, it was found that the main migrating species was also Cu atoms which were driven towards the cold end to form thicker Cu₆Sn₅ IMC layer at the cold interface under temperature gradient. Finally, thermo-electric coupling was realized by superimposing TM on EM with current density of 1.0 × 10⁴ A cm⁻². TM played the assisting or counteracting effect on the Cu migration occurred in EM when the anode was connected with cold end or hot end. With anode on hot end, TM played the reverse effect on the migration of Cu atoms, which prevented Cu atoms to be accumulated at the anode/hot interface. With anode on cold end, TM played the accumulative effect on the migration of Cu atoms, which led to a thicker IMC layer at the anode/cold interface.

This paper presents a new approach for the analysis of AC conductivity, ${\sigma }^{* }(\omega )$ = ${\sigma }^{{\prime} }(\omega )$ + $i{\sigma }^{{\prime\prime} }(\omega )$, in disordered solids which brings together the quasi-universal frequency-dependent conductivity and the idea of a Gaussian distributions of probable activation energy barriers for hopping carriers. An explicit expression for AC conductivity was obtained using a complex dielectric response function and a continuous time random walk treatment applied to a lattice obeying the Kubo's fluctuation-dissipation theorem. This expression provides an insight into the universality of the form ${\sigma }^{{\prime} }(\omega )\propto {\omega }^{s}(0\leqslant s\leqslant 1)$ and ${\sigma }^{{\prime\prime} }(\omega )\propto k\omega$ (k is the dielectric constant), as well into the effect of the Gaussian disorder on exponent s. We discuss the similarities and differences with the Random Free Energy Barrier model equivalent to the long-used box model, and it brings support to an extending expression proposed by J C Dyre and one of the authors. The applicability of the model to experimental observations on poly[(2-methoxy-5-hexyloxy)-p-phenylenevinylene] reveals the dielectric constant, mean energy and variance of the Gaussian distribution for hopping carriers in this disordered conjugated polymer.

Graphical Abstract

The role of Gaussian distribution of activation energy barriers for hopping carriers in the quasi-universal frequency-dependent conductivity of the form ${\sigma }^{{\prime} }(\omega )\,\propto \,{\omega }^{{\rm{S}}}(0\,\leqslant \,{\rm{S}}\,\leqslant \,1)$.

This paper presents the first frequency scanning array on a flexible substrate constructed using printed electronics methods and systems. Devices were designed using a printed wide band stacked ellipsoid antenna and phase shifter network with 50 ohm matching power splitters which was developed using Ansys Electromagnetics. These devices were produced in both 1 × 4 and 1 × 8 antenna patch configurations. The resulting devices were then tested to demonstrate beam steering as a function of frequency at 4.35 GHz, 5.32 GHz, 6.27 GHz, and 7.2 GHz and compared. Additionally, bending tests were performed to demonstrate the usability of the devices in a flexible, internet of things oriented application. The demonstrated devices have a multibeam receiving and transmitting capability while being inexpensive and easy to produce in a flexible package.

Inspired by Benzene (Bz) derivatives dramatically enhancing MoS₂ monolayer electronic properties (ACS Nano. 2015, 9, 6018–6030), we have investigated electronic and transport properties of (Bz)_n/MoS₂ and (VBz)_n/MoS₂, which are designed by grafting (Bz)_n and (VBz)_n arrays onto 2D monolayer MoS₂ (ML-MoS₂), respectively, using density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods. ML-MoS₂ provides a perfect substrate for grafting (Bz)_n and (VBz)_n arrays upon its surface as a result of stable covalent binding energy with −3.841 eV and −1.953 eV for (Bz)_n/MoS₂ and (VBz)_n/MoS₂ respectively. From the electronic properties, we can find that grafting (Bz)_n onto the ML-MoS₂ surface turns ML-MoS₂ from typical semiconductor to metallic properties because four wide bands coupled by (Bz)_n and MoS₂ in (Bz)_n/MoS₂ show better delocalization in heterointerface, resulting to these bands across the Fermi level (E_f). Furthermore, (VBz)_n nanowire grafted on the ML-MoS₂ further enhances the conductivities due to the introduction of metal V. Transport properties of ML-MoS₂, (Bz)_n/MoS₂ or (VBz)_n/MoS₂ for two-probe devices are all studied in zigzag and armchair direction. By comparison the zigzag direction is the preferential pathway for electron transport. The ferromagnetic (VBz)_n/MoS₂ shows a spin polarized transport characteristic, spin-down state gives a higher conductivity than spin-up state. Finally this work suggests that the novel (VBz)_n nanowire grafted on MoS₂ should have potential application in low-dimensional magnetic nanoelectronic devices.

Full-solution processed and all-inorganic electroluminescent devices are regarded as a promising technology for high-resolution displays and solid-state lighting due to their low-cost and air stable properties. In this work, hole transport layer-free and full-solution processed all-inorganic quantum dot light emitting diodes (QD-LEDs) were fabricated successfully. We employed a simplified device architecture of glass/ITO/Mg(OH)₂ (2 nm)/QDs (18 nm)/ZnO (75 nm)/Al (100 nm) and utilized insulating Mg(OH)₂ layer to balance the electron and hole charge transportation. All of the device fabrication procedures were carried out in ambient condition except for thermally evaporating and the completed QD-LEDs were measured in the open air without any encapsulation. A maximum luminance of 2930 cd m⁻² and current efficiency of 1.08 cd A⁻¹ were obtained with a low turn-on voltage of 1.6 V.

The effect of substrate temperature on the plasma-chemical etching rate of lithium niobate (LiNbO₃) single-crystals in an inductively coupled plasma (ICP) is studied in this paper. we found that the etching rate is a complex function of a substrate temperature with an interval where increases in the temperature lead to a significant growth of the etching rate. comparing the results of LiNbO₃ etching in two different gas mixtures (SF₆/O₂ and SF₆/Ar) showed that the etching process in SF₆/O₂ mixtures provides a higher productivity and a qualitatively better surface roughness. the maximum etching rate achieved during this research was more than 800 nm min⁻¹. The deep linbo₃ etching process (more than 113 μm) using an applied high frequency (HF) source with a power of 700 W was implemented, resulting in an etching rate of more than 420 nm min⁻¹.

Recently, ferroelectric tunnel junctions (FTJs) have attracted considerable attention due to their great potential in next generation non-volatile memories. In this work, we report on thickness-dependent tunneling electroresistance (TER) and corresponding evolution of transport behavior in Pt/BaTiO₃/LaNiO₃ FTJs with various BaTiO₃ thicknesses of 2.0, 3.2, and 4.8 nm. The TER effect is observed in the 3.2 nm-thick Pt/BaTiO₃/LaNiO₃ tunnel junction and an ON/OFF current ratio of ∼170 is achieved due to the modulation of barrier height by polarization reversal. When the BaTiO₃ is increased to 4.8 nm in thickness, the ferroelectric-modulation of the barrier profile becomes more pronounced and the dominant transport mechanism changes from electron tunneling to thermally-activated thermionic injection. As a result, the OFF state current is significantly reduced due to the suppression of the Fowler-Nordheim tunneling with increased width and height of the BaTiO₃ barrier. A greatly improved ON/OFF current ratio of ∼12 500 is thus achieved in the 4.8 nm-thick Pt/BaTiO₃/LaNiO₃ FTJ device. These results facilitate deeper understanding of the TER effects from the viewpoint of not only the barrier profile but also the transport mechanism.

(1−x)(Bi_0.5Na_0.5)TiO₃-xBa(Ni_0.5Nb_0.5)O₃ (x = 0–0.04) lead-free ceramics (abbreviated as (1−x)BNT-xBNN) were synthesized by a conventional solid-state reaction method. The effect of BNN contents on phase structure, microstructure, ferroelectric, dielectric, pyroelectric properties and thermal stability of (1−x)BNT-xBNN ceramics were systematically investigated. The pyroelectric coefficient (p) at room temperature increased gradually from 3.01 × 10⁻⁸ C cm⁻²K⁻¹ at x = 0 to 5.94 × 10⁻⁸ C cm⁻²K⁻¹ at x = 0.04. The dielectric loss (tan δ) and dielectric constant (ε_r) decreased first with the small amount of BNN content, then increased slightly with further BNN addition, acquiring the minimum tan δ and ε_r at x = 0.02. When x = 0.02, the optimal over-all properties were observed with pyroelectric figure of merit (FOMs) of F_v = 3.82 × 10⁻² m² C⁻¹ and figure of merit of F_d = 2.74 × 10⁻⁵ P a ^−1/2. More importantly, the depolarization temperature (T_d) of 0.98BNT-0.02BNN ceramics is up to ∼195 °C which is higher than most other reported BNT-based ferroelectric ceramics. In addition, it can be exposed to temperature up to ∼145 °C with negligible deterioration of pyroelectric properties, showing excellent thermal stability. The overall properties reveal that 0.98BNT-0.02BNN ceramics is a promising pyroelectric material for infrared detectors.

Thin foils based on the TiO₂ phase of brookite, 620 nm thick, were obtained by magnetron sputtering. The samples were irradiated at the DC-60 heavy ion accelerator of the Astana branch of the Institute of Nuclear Physics with Fe⁷⁺ ions with an energy of 85 MeV with a fluence of 1 × 10¹¹ to 1 × 10¹⁴ ions cm⁻². The dependences of the change in the concentration of defects in the structure of thin films on the radiation dose are established. It has been established that an increase in the irradiation fluence of up to 10¹⁴ ions cm⁻², characteristic of the formation of defect overlap regions, leads to a sharp decrease in the degree of crystallinity and an increase in the lattice parameters. That is caused by the formation of a large number of disorder regions and displaced atoms in the structure, which migrate along the crystal lattice to additional distortions and voltages, with the subsequent formation of hillocks.

Ag–28Cu–xNi (x = 0, 0.75, 1, 2 wt%), alloys are silver-based vacuum filler metals. The effect of Ni additions on melting characteristics, phase structure, as-cast and cold-working microstructures, interface morphology, mechanical properties and brazing properties of Ag–28Cu–Ni alloys were investigated, respectively. The results indicated that the solidus temperature, liquidus temperature and temperature range of the solid-liquid phase respectively increase from 778.1, 780.2, 2.1 to 783.6 °C, 815.4 °C, 31.8 °C as the Ni content increase from 0 to 2 wt%. Ag–28Cu–Ni alloy are mainly composed of Ag-rich α-phase, Cu-rich β-phase and (Ag+Cu) eutectic structures. The addition of Ni in the Ag–28Cu alloy will transform the eutectic structure into the segregation structure. Besides, with the increase of deformation, the tensile strength of Ag–28Cu–Ni alloy increases with the appearance of deformation texture. With the Ni content increase from 0 to 2 wt%, the spreading rate of Ag–28Cu–Ni filler metal on the Cu substrate increase from 158 to 176 cm² g⁻¹ and the shear strength of the Cu/Ag–28Cu–Ni/Cu brazed joint increase from 161 to 183 Mpa. Furthermore, the tensile fracture initiation source of the Cu/Ag-28 Cu/Cu joint is located at the interface between the Cu-rich phase and the Ag-rich phase, and the crack propagates in the Ag-rich phase of the fracture joint. But the cracks crack and expand in the Ag-rich phase of the brazing seam as the Ni content increases.

In this research, Zr-doped GaN thin films having same thickness (60 nm) were grown onto different substrates i.e. glass and PET (polyethylene terepthalate) by means of thermionic vacuum arc (TVA) technique at room temperature (RT). The structural characteristics of the obtained Zr-doped thin films were investigated by using an x-ray diffractometer (XRD). The obtained results indicate that the films contain crystal phase with (113) oriented GaN. The optical properties such as reflectance and refractive index were determined using an optical thin film analyzer. From the optical analysis, the refractive index at the wavelength of 632.8 nm was found as 2.55 for the film on glass and 2.60 for the film on PET. The surface properties of the produced thin films were characterized by atomic force microscope (AFM). The observation is that the surface morphologies of the films are homogeneous and granular. Hall measurement system was used for the electrical measurements in RT. The conductivity type of Zr-doped thin films was determined as n-type.

Pentacene thin films grown on SiO₂ substrates with few micron-spaced patterns were found to show anisotropy in their photoluminescence (PL) responses. PL emission was maximum for excitation polarization parallel to the groove direction. Detailed analysis of polarized Raman spectra gave insight on the intermolecular coupling. The anisotropy in PL was found to arise from preferential in-plane molecular alignment of pentacene, induced by the walls of the grooves. This was verified by spatial scan of the polarized micro-PL emission. Though earlier reports have shown anisotropy for nanoscale patterned substrates, to our knowledge, controlled orientation of molecules induced by micron spaced patterning has not been reported so far. This work reports observation of six fold increase in PL response for polarization parallel to the groove of widths 5 μm.

With a modified solution-processing method, isotactic polypropylene (iPP) ultrathin films (∼160 nm) are fabricated and investigated, which reveals a multiscale morphological effect of intramolecular interaction, lamellar orientation and intra-spherulite structure on the macroscopic carrier transport process. The morphology of ultrathin films is tuned by annealing under various temperatures (T_a) from 140 °C to 170 °C. It is found that when T_a < 160 °C, the lamella has a more flat-on like orientation. The spherulite size grows steadily with T_a. However, when T_a ≥ 160 °C, the morphology varies dramatically from spherulite-like to seaweed-like with lamella oriented edge-on. Depending on the microstructure, the electrical conduction characteristics of iPP ultrathin film changes, correspondingly. The conductivity is estimated from the long-term polarization current, which follows a hopping mechanism with a hopping distance about 1.5 nm and a critical field about 100 MV/m. It is proposed that the morphological changes with T_a result in more structural disorders, smaller inter-spherulite weak regions, and well-developed microstructure, which greatly suppress the electrical conductivity of iPP ultrathin films over one order. The present work reveals the essential role of multiscale morphology on the electrical property, which is of help for establishing the structure-property relation.

Five Al specimens (99.301 wt% pure) were anodized in 0.3 M oxalic acid at 0 °C and 40 V for five different anodization times in the range 5–30 min. The thickness of the anodic alumina films was measured by SEM as well as calculated by Faraday's Law. It was found that the average current (4.71 mA), average current density (2.14 mA cm⁻²), and average growth rate (57.37 nm min⁻¹) of the anodic alumina films remain independent of anodization time. The total charge transferred (1.42–8.16 C) and thickness of alumina film ${d}_{FL}$ calculated by Faraday's Law (0.29–1.66 μm) increase linearly with the increase in anodization time from 5 to 30 min. It was established that the value of film thickness ${d}_{SEM}$ measured by SEM (5–79 μm) also increases linearly with the anodization time. However, the value of ${d}_{SEM}$ was substantially greater than that of ${d}_{FL}.$ The relation between ${d}_{SEM}$ and ${d}_{FL}$ can be described by ${d}_{SEM}$ = R (t, V, T) × ${d}_{FL},$ where the value of multiplying factor R depends on the anodization time (t), voltage (V), and temperature (T). Analysis of the SEM top-view image micrographs of the anodic alumina films revealed that the pore diameter, interpore distance, and porosity of the anodic alumina film increase linearly with the increase in the anodization time. On the contrary, opposite behavior was observed in the case of pore circularity and pore density. The peak intensity of preferentially oriented (311) plane of Al substrate decreased whereas the FWHM increased on anodization, which means that the crystallographic nature of (311) plane was rather deteriorated on anodization.

Calcium-doped cuprous oxide (Ca:Cu₂O) thin films were effectively coated onto glass substrate by nebulizer spray technique with different doping percentage (0%, 1%, 2% and 3%). X-ray beam diffraction confirms the polycrystalline nature of the prepared Cu₂O thin film. An increase in size of the crystallites from 11 nm to 29 nm was observed for the increase of doping concentration. AFM study exposed a smooth surface with evenly dispersed grains and the change in roughness on the film surface was also noticed. Optical measurements showed the band gap varied from 2.40 eV to 2.15 eV for undoped and doped films. All the films were with narrow emissions band at 630 nm for excitation at 450 nm from the PL spectra. Hall Effect measurements showed that the prepared films have p-type conducting nature with resistivity value of 0.453 × 10² Ω cm and the carrier density of 21 × 10¹⁹ cm⁻³ for the 3% Ca-doping concentration. Solar cell characteristics such as an open circuit voltage (V_oc) of 0.30 mV, fill factor (FF) of 0.33 and conversion efficiency (η) of 0.45% were attained for 3% Ca doped Cu₂O film.

FePdSi and FePdSiN nanocomposite films were fabricated successfully on quartz glass substrate by direct current reactive magnetron sputtering. Under the same preparation parameters, the Fe/Pd ratio of FePdSi and FePdSiN films was unbalanced, which emerged obvious difference in morphology, microstructure and magnetic properties. The addition of N played an important role on the molecular free path and sputtering rate of Fe–Pd–Si film. Preferential combination of N with Si formed an amorphous Si–N matrix between the FePd nanoparticles, which improved the coercivity, maximum magnetic energy product and remanence ratio up to 2.8 kOe, 9.4 MGOe and 0.99 after thermal treatment at 550 °C, respectively. The mechanism was proposed to account for this unique growth technique.

Substrate temperature and methane concentration in Hydrogen (H₂) gas mixture is the main source for increasing the growth rate, nucleation and grain size of a synthetic diamond. The downside of such an approach is reduced quality. By increasing the chamber pressure, although the quality can be improved, however, it leads to a decrease in the crystal growth rate. Thin diamond films were deposited under hydrogen (H₂) and methane (CH₄) gas mixture using microwave plasma chemical vapor deposition (MPCVD) technique. The effect of methane concentration (1%–5%), growth temperature, and pressure on the nucleation of diamond thin films on diamond substrates was investigated. The growth temperature and pressure were maintained in the range of 925 °C–950 °C and 72–75 Torr, respectively. Single crystal diamond (SCD) thin films have been prepared on diamond substrates, which play an important role in the application of the diamond detectors. Different dimensions of films were obtained on diamond substrates with different thicknesses such as 209.17 μm, 401.73 μm, and 995.03 μm for the sample with 1%, 2% and 5% of methane concentration respectively. The roughness, as well as growth rate of these films, were also investigated and were found to be 4.23 nm and 5.02 μ h⁻¹, respectively for 5% methane by optimizing the substrate temperature at 950 °C. Different characterization techniques were used to study the structural, morphological, and compositional properties of the deposited diamond films which confirmed the crystallographic order of the developed diamond film on the diamond substrates.

Cobalt sulfide thin films have been efficaciously fabricated by physical vapour deposition technique (PVD). Diethyldithiocarbamato metal complexes of the overall formula [M(S₂CN(Et)₂)n] (M=Co,Cu) have been manufactured and used as precursors for the deposition of pure and copper sulfide doped cobalt sulfide thin films on glass substrate. X-ray diffraction and Fourier transform infrared analysis of thin films confirmed the cubic and spherical sheet like structures. UV–vis studies revealed that absorption peak shifted from higher to lower wavelength with the reduction in transmittance and reflectance. While the scanning electron micrographs confirmed the cubic metal sulfide particles with the band gap calculated as 2.4–2.0 eV in metal sulfide thin films. These complexes are the first in their class to be used as single source precursors to deposit Cu_xCo_1−xS₂ thin films.

TiO₂/SiO₂ films were deposited on glass substrates by sol-gel method, and the effects of SiO₂ on the photocatalysis and hydrophilicity of TiO₂ films were studied. Zeta potential measurements show that SiO₂ can effectively inhibit the growth of TiO₂ colloidal particles, and improve the stability of sols. XRD and AFM observations discover that, with the increase of SiO₂, the size and crystallinity of TiO₂ particles, and the porosity and roughness of films all gradually decrease. XPS and FTIR analyses indicate that SiO₂ also affect the composition of the films. In addition, the blue shift of the absorption boundary gradually increases with SiO₂. The fitting results show that the photocatalytic reaction of films basically follows the first-order kinetics law. The films with 15% SiO₂ exhibit the best photocatalytic activity, whose degradation efficiency is about twice that of the pure TiO₂ films. The films with 20%wt SiO₂ have the best super hydrophilicity, whose water contact angle (WCA) drops to 2° in 3s. More significantly, its super hydrophilicity can last for more than 6 days under dark, that is, the films obtain an enhanced durable super hydrophilicity. In summary, the films with 15%wt–20%wt SiO₂ own the best overall performance.

Fe element settlement in the ZnO matrices has been investigated through prepared single doped, co-doped with Mg and triple doped with Mg and Cu by a systematic x-ray Photoelectron Spectroscopy (XPS) and Electron Paramagnetic Resonance (EPR) measurements as well as the structural and morphological analysis through x-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) measurements. Also, effects of different solutions, nitrate and chlorate, on the Fe doping has been studied. XRD measurements have exhibited that crystal quality of the thin films deteriorates as the Fe doping level increases. On the other hand, Fe co-doped and triple doped with Mg and Mg + Cu has converted the dominant crystal plane direction from (002) to (101) and (100), respectively. Single Fe doped ZnO thin films has shown the smoothest and uniform thin film surfaces while co-doped and the triple doped thin films has displayed overgrown surface morphology with 3D morphology. The XPS has been used to investigate the chemical environment of the Fe in the ZnO lattice and Fe element has been found to be in the Fe³⁺ state. Two signals have been observed at g ∼ 2.0 and g ∼ 4.3 which are attributed an electron trapped into oxygen vacancy and isolated Fe³⁺. As the concentration of Fe doping increases, the intensity of g ∼ 2.0 signal intensity increases significantly, while the g ∼ 4.3 signal intensity increases slowly. Temperature dependence of EPR signals in terms of intensity, linewidth and g-factor been investigated.

Titanium Nitride (TiN) coatings were deposited on stainless steel substrate using Cathodic Arc Deposition method. Coating uniformity and growth defects were analysed by the proposed image processing technique along with conventional XRD, SEM and surface roughness measurement. Corrosion experiments confirmed that coating exposed with coarse texture and more defect density shown with more corrosion rate. Regression model was developed to determine the significance of image features against corrosion nature of coating. The image features contrast, entropy and standard deviation are used to identify the uniformity of coating. Porosity of coating obtained from corrosion experiment highly correlated with the defect density estimated by image process.

DLC formation on sintered Al alloys and its purity is obtained for automotive applications. In this work, initial evaluation of DLC coatings was performed using scratch, micro-hardness, fracture toughness and surface roughness tests on sintered Al. Raman spectra analysis confirms the DLC formation. The DLC coated sintered Al samples exhibits micro-hardness in the range of 2000 to 2300 kg mm⁻² when measured using a Vickers diamond pyramid indenter of 0.5 N load applied on it. In some localized regions, even more hardness (>5000 kg mm⁻²) has been obtained. Scratch test results shows a fairly homogenous coating with strong adhesive nature having almost four times the average critical force compared to electro-statically deposited sample. Fracture toughness and surface roughness are well within the acceptable ranges of DLC coatings. The capability of laser sintering to produce thick DLC coatings with outstanding mechanical and tribological properties and excellent bonding with aluminium offers the possibility to tailor an extreme lightweight, strong and wear-resistant material. Nano indentation result indicates the information of plastic and elastic deformation for industry based applications.

An AlCrN/nitrided layer (NL) composite coating was fabricated on H13 hot work mould steel using a cathodic arc ion plating (CAIP) and low temperature plasma nitriding (LTPN). The surface and cross–section morphologies, chemical composition and phases of obtained coating were characterized using a scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and x-ray diffractometer (XRD), respectively. The salt spray corrosion (SSC) and electrochemical corrosion properties of AlCrN/NL coating in 3.5 wt% NaCl solution were analyzed using a salt spray corrosion chamber and electrochemical workstation. The results show that the AlCrN/NL composite coating consists of AlN, Cr_1.75V_0.25N₂, AlCrFe₂ and SiC phases, the formation of ceramic phases increases its corrosion resistance. The aggressive Cl^– is adhered on the corrosion products after the SSC test, the corrosive micro–cells and pitting corrosion are formed due to the differences of structure and relative potentials. The corrosion current densities of AlCrN/NL coating, NL and substrate are 3.255 × 10^–6, 9.848 × 10^–6, and 1.522 × 10⁻⁵ A · cm^–2, respectively, indicating that the corrosion resistance of AlCrN/NL coating is higher than that of NL and substrate. The polarization resistance of 11 798 Ω · cm² on the AlCrN/NL coating is 1.68 and 3.67 times higher than that of NL and substrate, respectively, which shows that the AlCrN/NL coating increases the corrosion resistance of substrate.

This work presents a study on how threshold voltage (V_T) varies with the change in shapes (rectangular and interdigitated finger) and size of the coplanar electrode in electrowetting-on-dielectric (EWOD) device. The EWOD device is fabricated on glass substrate with aluminimum (Al) electrode. Next, synthesized nanocomposite thin film of BST/Teflon^® AF is coated on the coplanar electrodes to act as both dielectric and hydrophobic layer. Experiments show that change in electrode dimension (or shape), such as electrode length (L), gap (G) and no. of teeth (T) result in different contact line (CL) between the droplet and the actuated electrode. This leads to change in V_T for droplet transport. It is found that higher contact line results in lower threshold voltage, while lower contact line results in higher threshold voltage. This finding matches with the reported theory in literature.

The present study investigates optimisation of microhardness of electroless Ni–Co–P alloy coating over copper substrate. The microhardness of the coating was significantly higher compared to the substrate. Three different design factors i.e., the concentration of cobalt sulphate, concentration of sodium hypophosphite and bath temperatures were used as the process parameters which were optimised by using Box Behnken Design (BBD) and coating micro hardness was taken as a response factor. Vickers' hardness test was conducted to obtain the micro hardness values of the coated samples. From the model analysis results, it was found 15 g L⁻¹ of cobalt sulphate, 25 g L⁻¹ of sodium hypophosphite and a bath temperature of 85 °C were the optimum conditions for the coating deposition in order to obtain the hardness value of 1921 HV_10g. After annealing at 350 °C the hardness value was further enhanced to 1990 HV_10g. Analysis of variance (ANOVA) was carried out to find the graphical relationship between the different process parameters. The detail surface morphology of the Ni–Co–P coating was studied by using an optical microscope and a Scanning Electron Microscope (SEM). The phase and elemental compositions were determined by x-ray Diffraction (XRD) analysis and Energy Dispersive x-ray analysis (EDX).

Laser blanking process is widely used for the ability to cut complex profiles on sheet metal without Die. Laser blanking process needs optimization methods to reduce wastage of raw material and cutting time. The work entails optimization of sheet metal nesting allocation to reduce wastage and also optimizes cutting time by reducing ideal travel distance. The laser irradiation induces heat affected zone in the cutting surface leading to poor service life of the components in the cutting edges. The development of AlN heat zone spread resistance coating over steel substrate through a reactive sputtering process is presented. The thin film preparation is carried out in two different combinations of Argon and Nitrogen ratio namely 1:1 and 2:1, respectively. The coating over the steel substrate is exposed to laser to analyze the micro-structural change induced by the laser in the cutting edges. The coating is observed to mitigate the spreading of heat zone. The coatings are further subjected to tafel polarization to analyze the corrosion resistance of the steel substrate. In this paper, an approach has been made to obtain an optimal allocation based on the selection of different dimensions of the AlN coated sheet and also to calculate the utilization and cutting time. The proposed method provides an optimal layout for parts using a software and to obtain minimum travel ideal distance a heuristic algorithm is used. Since the sheet is coated there is also an add-on advantage in minimizing cutting time. Finally, an Optimal Pareto front is developed between wastage and ideal cutting distance, in order to provide choices for the user to select the requirement in both cases.

Extensive optical study has been carried out on as-deposited and annealed thin films of Ge₁Sb₂Te₄ and GeSbTe chalcogenides prepared through vacuum thermal evaporation on glass substrates. These films are found to be amorphous in nature for as-dep samples. The modifications that manifest in these films upon annealing are thoroughly investigated in view of the optical parameters. UV–vis spectroscopy has been utilized as the major tool for computation of optical constants, optical bandgap energy, urbach energy, skin depth, optical conductivity etc. Theoretical models for optical analysis like Wemple Di-Domenico model and Single Sellmier model have been applied to evaluate the dispersion energy parameters and oscillator parameters. Comparative analysis has been carried out which highlights the phase change characteristics of Ge₁Sb₂Te₄ and non-phase change behavior of GeSbTe.

The relationship between residual stress and growth behavior of anodic titanium oxide films (TiO₂) was investigated in terms of defect chemistry and the nanocrystalline materials thermodynamic. The results showed that the surface residual stress can be controlled by acting on the duration of the surface mechanical attrition treatment (SMAT). When samples are processed by grinding for 30 min, the residual stress value reaches a maximum of 73.13 MPa, approximately 7.2 times higher than the one obtained with untreated sample. Under these conditions, the thickness of the anodic film was abound 1200 nm, three times that of the TA2 anodic film. Furthermore, the results of electrochemical tests showed that following the surface mechanical attrition treatment, the anodic film show lower density vacancies, higher resistance to the diffusion of Cl⁻, higher density, and an improved corrosion resistance when compared to TA2. Generally speaking, the growth behavior of the anodic film can be improved by identifying the suitable residual stress.

The adsorption and inhibitor effect of Expired Amoxicillin (E.A) on mild steel in 1 N HCl was studied by weight loss, potentiodynamic polarization, Electrochemical Impedance Spectroscopy (EIS), zero-charge potential method (PZC) and characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The inhibition efficacy obtained by gravimetry is 94.47% at 1800 ppm after 8 h immersion. Amoxicillin acts as a mixed inhibitor. The surface is negatively charged. E.A adsorption on mild steel surface obeys Langmuir isotherm, with a spontaneous process, the E.A molecules are physisorbed.

Effect of ammonium concentration on optical, structural and surface roughness properties of Nb₂O₅ thin films is conducted in this work. Estimated optical band gap and optical constant confirm the dependency of Nb₂O₅ thin films on ammonium molarity. The band gap in the range of 3.3 to 4.7 eV is directly related to the solution properties. The structural properties are recorded by x-ray diffraction method that display the formation of monoclinic niobium pentoxide (H-Nb₂O₅) thin films. Optimum molarity at 12 M reveals the prime ammonium concentration for the Nb₂O₅ thin films formation. The energy gap at optimum preparation state ensures the development of semiconducting material that suits solar cell and other optoelectronics application. AFM results show a highly uniform surface. Grain size is observed to increase with ammonium concentration and recorded to reach its maximum of 85.28 nm at 12 M.