Table of contents

Recent advances in the use of nano-emulsions are opening up new applications in the food industry. Food grade nano-emulsions are being utilized in the food industry for their physico-chemical properties in encapsulating of bioactive components, being as a carrier for bioactive components, and preventing their degradation, increasing bioavailability of essential oils by increasing its antimicrobial activity. The small size of the particles in nano-emulsions provides a number of potential advantages over conventional emulsions. They have higher stability to particle aggregation and gravitational separation (this high stability is used in elimination of toxic weighing agents in flavor emulsions), high optical clarity, ability to modulate product texture, and increased bioavailability of lipophilic compounds. Also, being translucent in nature can eliminate the use of alcohol as a clarifying agent in the beverage industry and, to ease obtaining Helal Certificate, which is desirable in many regions of the world. This current review presents general properties of emulsions and an overview of Food-Grade nano-emulsions, recent applications of nano-emulsions in the food systems and patent review of emulsions.

In this paper, the development status of titanium microalloyed high strength steels is comprehensively introduced, and the precipitation behaviors of titanium, including the strain-induced precipitation and interphase precipitation of nano-sized carbides, are illustrated in detail. Moreover, the future trend of titanium microalloying technology is also discussed, which provides insightful suggestions for not only the prospective developments but also the potential industrial applications of these titanium microalloyed steels.

Advanced functional Materials play an ever increasing and effective role in our modern community. These materials have tremendous impact on a variety of technologies, including memory and light-emitting devices, magnetic data storage, nanolithography, photo-electronic devices, MEMS devices, energy storage, electromagnetic interference shielding, actuators, sensors, and biomedicine. The growing interest in polymer-derived ceramics (PDCs) in the last two decades has been mainly associated with their use as initial precursors for the synthesis of multifunctional materials. Polymer-derived ceramics, also known as preceramic organosilicon polymers, provide an effective, safe and rapid process for producing technical ceramics; the main advantages being processing (easy shaping/forming using polymeric processing techniques e.g. melt spinning, extrusion, injection molding, coating, and low firing temperatures) and desirable material properties. Polymer-derived ceramics have emerged as a promising class of ceramic materials, which are generally synthesized through controlled thermal degradation of polymeric precursors in inert atmosphere. This quick, straightforward polymer-to-ceramic conversion can be used to produce homogeneous and high-purity composite materials with a novel composition and exceptional properties. The incorporation of fillers, either active or passive, into the preceramic polymers can induce various functionalities and generate a wide range of compositions and ceramic morphologies, possessing outstanding properties. The concept of fillers provides an invaluable tool for obtaining not only crack-free monolithic pieces, but also modifies the chemistry and architecture of PDCs. Thus far, the majority of research has been directed toward designing and engineering organosilicon materials for structural applications, rather than biological, electronic and magnetic applications. The motivation of the present review is to provide a comprehensive understanding of all processing strategies for the modification of preceramic polymers and resultant functional properties of polymer-derived ceramic composites. This review discusses the available literature focusing mainly on: (i) biological tests; (ii) filler-free and filler-containing polymers for electronic applications; (iii) magnetic properties of metallopolymers and filler-containing PDCs; and (iv) optical properties. Polymer-derived functional composite materials are seen as providing a potential platform for creating new arenas where these materials might make an impact.

In this study, branched TiO₂ nanotube array were fabricated through electrochemical anodization process at constant voltage using third generation electrolyte. On account of morphological advantage, these nanotubes shows significant enhancement in photo-electrochemical property than compact or conventional titania nanotube array. However, their photo-electrochemical efficiency intensifies on coating with ZnO micro-crystals. ZnO coated branched TiO₂ nanotube array shows a photocurrent density of 27.8 mA cm⁻² which is 1.55 times the photocurrent density (17.2 mA cm⁻²) shown by bare branched titania nanotubes. The significant enhancement in photocurrent density shown by the resulting ZnO/TiO₂ hybrid structure is attributed to suppression in electron–hole recombination phenomenon by offering smooth pathway to photo generated excitons on account of staggered band edge positions in individual semiconductors.

Magnesium (Mg) is currently known as one of the potential candidates for hydrogen absorbent material because theoretically, it has the ability to absorb hydrogen in large quantities of 7.6 wt%. However, the kinetic reaction of Mg is very slow; to absorb hydrogen takes 60 min with high operating temperature (>400 °C). Therefore, we have studied MgH₂-Ni-SiC-based storage system. The objective of this study is to improve the hydrogen desorption temperature and the hydrogen desorption capacity. The material preparation was done through mechanical alloying technique. In this method, the milling of the material was carried out within 5 h, 10 h and 15 h, with the ratio of the ball to powder, was 10:1 with the catalyst by 5 wt% and 10 wt% SiC. The results from XRD measurements revealed that the sample was successfully reduced to a nanocrystal scale. The phase emerging from the XRD observation is the phase MgH₂ as the main phase and followed by Ni and SiC phase as the minor phase. Our SEM observation showed the irregular particle shape, the particle size in the sample is not homogeneous because of the agglomeration effect and coldwelding that causes the particle size to look larger. Based on the observation with DSC, the temperature obtained in the samples milled 10 h with catalyst 5 wt% SiC was 365 °C.

We have investigated the magnetic and microwave absorbing properties of barium hexaferrite BaFe_12−2xCo_xZn_xO₁₉ (x = 0.0; 0.2; 0.4; 0.6) nanocrystalline prepared using solid state reaction method. The powder of these ferrites were resulted by high energy ball mill for 1 h and mixed with epoxy resin to be converted into a microwave absorbing composite. The results show barium hexaferrite structures for Ba(Fe,Co,Zn)₁₂O₁₉ have been formed. The coercive force (Hc) decreases rapidly with the substitution of Co and Zn in the structure of Ba(Fe,Co,Zn)₁₂O₁₉. It's indicate that the Co-Zn in the structure of Ba(Fe,Co,Zn)₁₂O₁₉ contributes to magnetic and microwave absorption properties. The minimum reflection loss value of −29.98 dB was observed at 10.8 GHz with a matching thickness of 1 mm for BaFe_12−2xCo_xZn_xO₁₉ (x = 0.6) nanocrystalline. As results, the magnetic absorbing properties improve significantly by Co-Zn incorporation.

Sm_xSn_1−xO₂ thin films (with x = 0, 0.005, 0.02 and 0.04) were sputter deposited on Si (100) substrates and its physical properties were investigated. The as-deposited thin films were amorphous; however after electron beam rapid thermal annealing became polycrystalline tetragonal phase [JCPDS21-1250]. The preferred crystal growth orientation of the annealed thin films were along (101) plane, in contrast with its bulk where it is along (110) plane. However in both cases the crystallinity of Sm_xSn_1−xO₂ thin films reduced with increase in Sm dopant concentration. The annealed thin films showed continuous grain distribution, with linear increase in grain size from ∼12 to ∼52 nm with increase in Sm dopant concentration. Maximum magnetization of 0.031 emu was observed in annealed Sm_0.04Sn_0.96O₂ thin film. The observed weak ferromagnetism in the thin films could have originated from the induced oxygen vacancies through Sm substitution and electron beam rapid thermal annealing in high vacuum. It was also observed that the optical absorption of doped SnO₂ thin films (in 300 to 800 nm range) decreased by Sm doping. These observations suggest that Sm doped SnO₂ thin films can be potentially used for dilute magnetic semiconductor and solar cell application.

Mixed spinel copper manganese ferrite (Cu_XMn_1−XFe₂O₄, X = 0, 0.25, 0.5, 0.75, 1) nanoparticles were synthesized by chemical co-precipitation technique. From the powder x-ray diffraction analysis the lattice constant, volume of unit cell, x-ray density, hopping lengths, crystallite size, surface area, dislocation density and microstrain were calculated. The substitution of Cu²⁺ ions shows a considerable reduction in the crystallite size of manganese ferrite from 34 nm to 22 nm. Further a linear fit of Williamson-Hall plot has been drawn to determine the microstrain and crystallite size. The crystallite size and morphology were further observed through high resolution transmission electron microscope and scanning electron microscope. The diffraction rings observed from selected area electron diffraction pattern exhibits the crystalline nature of all the samples. The energy dispersive x-ray analysis shows the composition of all the elements incorporated in the synthesized nanomaterials. FTIR studies reveal the absorption peaks that correspond to the metal-oxygen vibrations in the tetrahedral and octahedral sites. From the UV–vis absorption spectra the band gap energy, refractive index and optical dielectric constant were determined. Magnetic studies carried out using vibrating sample magnetometer shows interesting behaviour in the variation of magnetisation and coercivity. Peculiar magnetic behaviour is observed when Cu²⁺ ions are substituted in manganese ferrites. All the synthesized materials have very low value of squareness ratio which attributes to the superparamagnetic behaviour.

In this study, we present the synthesis of nickel oxide nanofibers through electrospinning technique at optimum processing and heat treatment conditions. The diameter and uniformity of electro-spun nickel oxide nanofibers were investigated as a function of PVP concentration. Uniform and homogeneous composite nanofibers were observed for PVP:Ni(CH₃COO)₂·H₂O ratio of 1:1. X-ray diffraction and scanning electron microscopy of samples calcined at 600 °C revealed the formation of uniform but porous single phase nickel oxide nanofibers of an average diameter $\sim 170\,{\rm{nm}}.$ Electrical properties of nickel oxide nanofibers, obtained at optimum conditions, were studied using inter-digitated electrodes type device. Temperature-dependent impedance spectroscopy revealed different electro-active regions (grain and grain boundaries) and their activation energies were 0.24 and 0.36 eV, respectively. These results suggested less resistive grain than grain boundary in the employed temperature range, and hence, two different transport mechanisms.

The pure cobalt thin film was deposited on the glass substrate by using DC magnetron sputtering and then exposed to microwave assist oxygen plasma generated in microwave plasma CVD. The oxidation process of Co thin film into Co₃O₄ thin films with different microwave power and temperature were studied. The influences of microwave power, temperature and irradiation time were investigated on the morphology and particle size of oxide thin films. The crystal structure, chemical conformation, morphologies and optical properties of oxidized Co thin films (Co₃O₄) were studied by using x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Raman Spectroscopy and UV–vis Spectroscopy. The data of these films showed complete oxidation pure metallic cobalt (Co) into cobalt oxide (Co₃O₄). The optical properties were studied for calculating the direct band gaps which ranges from 1.35 to 1.8 eV.

Polyamide 6 (PA6)/layered double hydroxide (LDH) nanocomposites were prepared by in situ polymerization with different amount (1, 2, 3 wt%) and type (Zn/Cr-L and Zn/Cr-P) of LDHs. The thermal and mechanical properties and water absorption capacity of PA6/LDH nanocomposites were investigated and have shown that the addition of LDHs increases the crystallinity of the polymer and improves their mechanical properties, while decreases the water absorption capacity due to a barrier effect of LDHs. A correlation between mechanical properties and water absorption capacity was observed and discussed. This study provides new strategies for tuning PA6-based nanocomposite properties, leading a progress in the development on the advanced polymer materials.

In this present study nanostructured dually doped samples of Cd_1−x−yMg_xM_yO (M: Sn, Pb, Bi) are synthesized by SILAR method. The effects of the mono and dual doping on the structural, morphological and optoelectronic characteristics of CdO nanoparticles are examined. The SEM images verify that deposited CdO films are nano-sized. Also the SEM computations demonstrated that the morphological surface structures of the films were influenced from the Mg mono doping and (Mg, Sn), (Mg, Pb) and (Mg, Bi) dual doping. The XRD designs specified that all the CdO samples have polycrystalline structure exhibiting cubic crystal form with dominant peaks of (111) and (220). The results display that Mg and (Mg, Sn), (Mg, Pb) and (Mg, Bi) ions were successfully doped into CdO film matrix. The UV spectroscopy results show that the optical energy band gap of the CdO films, ranging from 2.21 to 2.66 eV, altered with the dopant materials.

Melamine and multi-walled carbon nanotubes (MWCNTs) were grafted onto Poly-p-phenylene benzobisoxazole (PBO) fiber surface effectively via layer-by-layer method. Both of them have been chemically bonded as fourier transform infrared spectroscopy (FTIR) confirmed. Grafting melamine overcame the inertness of PBO surface. Ammoniation was processed on PBO surface through grafting melamine so that the MWCNTs could be grafted onto PBO surface. Scanning electron microscopy (SEM) images indicated that melamine used as molecular bridge could increase MWCNTs' quantity on PBO surface. X-ray photoelectron spectroscopy (XPS) results revealed the variation of chemical composition of PBO surface. Test of interfacial shear strength (IFSS) and tensile strength indicated the great mechanical properties of modified PBO fibers when combining with epoxy resin. Furthermore, whole reaction was processed under a simple condition. Results in this research also promised a potential method to modify PBO surface.

Germanium oxide nanoparticle is synthesized from bulk GeO₂ powder through hydrothermal technique. The structural characterization of the prepared sample is performed with x-ray Diffraction and Transmission Electron Microscope. From the PL emission spectra and x-ray photoelectron spectra, the existence of oxygen defects inside the sample is confirmed. Thermogravimetric (TG) analysis of the sample shows that there is no weight loss with increase in temperature instead of a very little weight gain. An estimation of Oxygen vacancy concentration is made from the amount of weight gain as measured during TG analysis. The sample is also characterized with PE loop tracer, which indicates that GeO₂ nanoparticle is able to show hysteresis loop regarding variation of Polarization with electric field. Such phenomenon implies that the sample can be used as electrically erasable memory device. Further, GeO₂ nanoparticle is also exploited as photo catalyst to degrade Methylene Blue (MB) solution in the presence of ultraviolet ray. This phenomenon is also explained with oxygen vacancy.

In this study, Ag-doped TiO₂ hollow microspheres were synthesized by a template-free route, and their photocatalytic performance and catalytic mechanism were investigated. The hollow microspheres were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy and UV–vis spectroscopy. Ag-doped hollow TiO₂ microspheres exhibited excellent photocatalytic performance for tetracycline hydrochloride (TC) in water. TC degradation follows pseudo first-order kinetics, and hydroxyl radical (OH·) and holes (h⁺) were active substances in the photocatalytic reaction.

The paper presents the effects of hybridization and silica nanoparticles on unhole and open hole compressive behaviours of woven Kevlar/glass fibre hybrid composite laminates. Residual compressive strength and stiffness were determined from an open hole compression (OHC) test conducted according to ASTM D6484-09, whereas the fractured surface behaviour was observed under scanning electron microscope (SEM). Silica nanoparticles were mixed into the epoxy resins using vacuum mechanical stirrer. Then, composite laminates were prepared using vacuum bagging method. Three different silica nanoparticles contents (5 wt%, 13 wt% and 25 wt%) were incorporated into the resin system with three different hybrid system (20:80, 50:50 and 80:20 of Kevlar fibres to glass fibres ratio). Results showed that the lowest compressive strength was observed in Kevlar fibre reinforced polymer. Therefore, hybridization of glass fibres with Kevlar fibres reduced the compressive strength of hybrid composites. However, the incorporation of silica nanoparticles into the epoxy resins improved the compressive properties of the hybrid composites. From the observation of the fractured surface, different fracture behaviours were observed in both Kevlar fibre and glass fibre composites. Fibre barrelling and crimping was observed in Kevlar fibres while glass fibres showed a fibre fracture with serrated and rough surfaces.

This paper presents a formulation based on simple first-order shear deformation theory (S-FSDT) for large deflection and buckling of orthotropic single-layered graphene sheets (SLGSs). The S-FSDT has many advantages compared to the classical plate theory (CPT) and conventional FSDT such as needless of shear correction factor, containing less number of unknowns than the existing FSDT and strong similarities with the CPT. Governing equations and boundary conditions are derived based on Hamilton's principle using the nonlocal differential constitutive relations of Eringen and von Kármán geometrical model. Numerical results are obtained using differential quadrature (DQ) method and the Newton–Raphson iterative scheme. Finally, some comparison studies are carried out to show the high accuracy and reliability of the present formulations compared to the nonlocal CPT and FSDT for different thicknesses, elastic foundations and nonlocal parameters.

Molecular dynamics simulations were performed to study thermal properties and melting points of Al nanoparticles by using a reactive force field under canonical (NVT) ensembles. Al nanoparticles (particle size 2–4 nm) were considered in simulations. A combination of structural and thermodynamic parameters such as the Lindemann index, heat capacities, potential energy and radial-distribution functions was employed to decide melting points. We used annealing technique to obtain the initial Al nanoparticle model. Comparison was made between ReaxFF results and other simulation results. We found that ReaxFF force field is reasonable to describe Al cluster melting behavior. The linear relationship between particle size and melting points was found. After validating the ReaxFF force field, more attention was paid on thermal properties of Al nanoparticles with different defect concentrations. 4 nm Al nanoparticles with different defect concentrations (5%–20%) were considered in this paper. Our results revealed that: the melting points are irrelevant with defect concentration at a certain particle size. The extra storage energy of Al nanoparticles is proportional to nanoparticles' defect concentration, when defect concentration is 5%–15%. While the particle with 20% defect concentration is similar to the cluster with 10% defect concentration. After melting, the extra energy of all nanoparticles decreases sharply, and the extra storage energy is nearly zero at 600 K. The centro-symmetry parameter analysis shows structure evolution of different models during melting processes.

Graphene, a wonder material has inspired quest among researchers due to its numerous applications and exceptional properties. This paper highlights the mechanism and chemistry behind the fabrication of graphene oxide by using phosphoric acid. Chemical functionalization is of prime importance which avoids agglomeration of nanoparticles to attain inherent properties. As non-homogeneous dispersion limits its utilization due to interfacial interactions which restrict reactive sites to produce intercalated network. Thus, chemically functionalized graphene leads to stable dispersion and enhances thermal, mechanical and electrical properties of the resultant polymer composite materials. Solubility of graphene in aqueous solution is the major issue because graphene is hydrophobic, to rectify this oxygen containing hydrophilic groups must be introduced to make it compatible and this can be attained by covalent functionalization. Among all nanofiller GO has shown average particle size i.e. 95 nm and highest surface charge density. The characteristic changes were estimated using Raman spectra.

Titanium disulfide, being one of the popular transition-metal dichalcogenide (TMD) materials, shows wonderful properties owing to tunable optical band gap. Pure and PbSe doped titanium disulfide nanodiscs have been synthesized by solid-state reaction method. FESEM, TEM and Raman images confirm the synthesis of nanodiscs. XRD spectra suggest the polycrystalline structure of as-prepared as well as PbSe doped TiS₂ nanodiscs. PL spectra of the as-synthesized nanodiscs has been studied in the wavelength range of (300–550 nm), at room temperature. The position of the peak shifts towards the lower wavelength (blue shift) and intensity of the PL increases after the doping of PbSe, which may be due to a broadening of the optical band gap. UV–vis spectra has been used to calculate optical band gap of pure and PbSe doped titanium disulfide nanodiscs. The calculated value are found to be 1.93 eV and 2.03 eV respectively. Various optical constants such as n and k have been calculated. The value of extinction coefficient (k) of pure and doped titanium disulfide increases while the value of the refractive index (n) decreases with increase in photon energy.

The design of absorbents that can handle poisonous dyes in wastewaters is of great importance. Herein, we synthesize amino acid modified magnetic nanoparticles via a polydopamine (PDA) assisting strategy. By this strategy, a high adsorption of methylene blue reaches 950 mg g⁻¹, which is superior to most reported dyes absorbents. Furthermore, this synthetic route is very simple and the absorbents can be fast separated from waste water by virtue of their strong super-paramagnetism.

Pure ZnO nanoparticles (NPs) and Co/ZnO alloy NPs were synthesized with different percentages of cobalt impurity (1%, 3%, 5%, and 25%) with new precursors through the coprecipitation method. The structural results of the XRD analysis indicated that the pure and impure samples have a wurtzite hexagonal structure such that with an elevation of Co impurity up to 1%, the size of the nanocrystals declines by up to 30 nm. Furthermore, the FESEM analysis results suggest the homogeneity of the NPs such that with increased cobalt impurity, its level declines. The TEM analysis results revealed that the NPs with 5% impurity have a mean size of 32 nm in spherical form. The FTIR optical analysis results suggest a very sharp absorption peak within the wavelength ranges of 434–448 cm⁻¹, belonging to the Zn-O vibration bond. In addition, the absorption peak developed at the wavelength of 3428 cm⁻¹ is related to the activation of the OH radicals, whose absorption value grows with the addition of an impurity, thereby, causing enhanced photocatalytic activity. The UV-DRS optical analysis indicated that the absorption wavelength grows with increased impurity, causing the development of redshift and a reduction of the energy band gap. In this regard, for the pure sample, the band gap value was 3.18 eV, while for the sample with 5% impurity, the band gap was obtained as 2.68 eV. The VSM magnetic analysis suggests ferromagnetic development in the impure sample, with a saturation magnetism of 16 memu g⁻¹ and a coercivity field of 342 G.

The complex disease, cancer is caused by genetic uncertainty and various molecular alterations. Due to the present ineffective diagnostic and prognostic classifications, the complete heterogeneity of a tumor is not revealed which in turn affects the selection of suitable treatment and patient outcome. Cancer nanotechnology is an emerging interdisciplinary research field that covers important aspects of chemistry, engineering, biology and medicine, leading to the advancement of cancer diagnosis and treatment. Hence the main aim of this study is to develop lycopene loaded gelatin nanoparticles and evaluate its in vitro anticancer activity using breast adenocarcinoma cells.

This communication reports the synthesis and characterisation of two novel Intrinsic conducting polymer nano composites (ICPN s) with the formulae Ga _(2x+2) N Fe _2(49-x) O₃—PPY synthesized using Impregnation technique. The Gallium nitride ferrite nano particles were synthesized for x = 1 and x = 5 using the above stichiometric equation earlier by Sol—Gel route. The chemical composition in the assembly of the ICPNs were Ga₄NFe₉₆O₃-3%,10%,30% Polypyrrole, Ga₁₂NFe₈₈O₃-3%,10%,30% Polypyrrole by weight. The Sci-Finder software failed to trace any earlier articles or reviews related to these ICNPs synthesised by us in the literature. X-ray Diffractometric (Structural), Morphological, EDAX SAED, IR spectroscopic characterizations were done on the synthesized nanocomposites. Structural studies reveal the semi-crystalline nature of composites. The average crystallite size of nano composites is decreased when compared with nano ferrites. SEM findings reveal that the shape for higher percentage of PPY is nano rods; for lower percentage it is globular. TEM reveals good dispersion and average particle size from histograms are calculated. The FT- IR bands of PPY and GaNFe₂O₃ are observed which show strong interaction between PPY- GaNFe₂O_3. Also there is a shift of bands in GaNFe₂O₃-PPY nano composites when compared to the bands of PPY.

For optical thermometry, the pump light source has an important influence on the temperature measurement performance. In this study, we investigated the influence of 980 nm pump power on fluorescence intensity ratio (FIR) thermometry based on NaYF₄:5% Yb³⁺/2% Er³⁺ nanoparticles. The thermally coupled level (TCL) of ²H_11/2 and ⁴S_3/2 of Er³⁺ was selected to evaluate the temperature. The correspondence between the FIR and temperature of this sample near room temperature was observed. In addition, the relationship between the FIR and pump power was analysed. The temperature increment induced by the laser thermal effect and the uncertainty of the FIR of the sample were studied with an increasing power density. The results indicate that the uncertainty ratio of the FIR (ΔFIR/FIR) decreases rapidly with the pump power density, which implies that the precision of the temperature measurement is improved. While the temperature increment induced by the pump power increases linearly with a slope of 6 K/(W/cm²), this will reduce the temperature sensing accuracy. Clearly, this contradiction in utilizing a 980 nm pump power should be balanced in practical applications of optical thermometry.

In this current study, −NH₂ functions are introduced on Polyethersulfone (PES) by a nitration reaction then a reduction reaction to fabricate PES-NH₂ materials with a better hydrophilicity property. The structure of PES-NH₂ was first confirmed using proton nuclear magnetic resonance spectroscopy (¹H-NMR) and Fourier transform infrared (FT-IR) spectroscopy. Then, the resultant polymer was doped with different concentrations of ZnCdCrO nanocomposites. The polymeric nanocomposites materials were characterized using FT-IR, x-ray powder diffraction (XRD), thermal analysis (TA), and energy dispersive x-ray (EDX) spectroscopy while the morphology was investigated using scanning electron microscopy (SEM). The performance PES-NH₂-ZnCdCrO nanocomposites was investigated by sensor-probe towards the selective detection of Hg²⁺. The results showed the excellent thermal properties of PES-NH₂-ZnCdCrO nanocomposites in comparison with non-doped polymer (PES-NH₂). Here, Hg²⁺ ionic sensor was prepared using a flat glassy carbon electrode (GCE) coated with a thin-layer of PES-NH₂-ZnCdCrO nanocomposites (20%) with nafion conducting nafion binder (5%). To evaluate the analytical performances of Hg²⁺ ion sensor, a calibration curve was drawn by plotting the current versus concentration. The sensitivity (0.6566 μAμM-1 cm⁻²) and detection limit (14.46 ± 0.72 pM) are calculated using the slope of the calibration curve. It was determined the linearity (r² = 0.9941) over the large linear dynamic range (LDR) (0.1 nM to 0.1 mM). Thus, this research approach might be an important route to the selective detection of environmental toxin (Hg²⁺ cation) from the aqueous system in broad scales for the safety of health care, environmental, and aquatic fields.

Maghemite nanoparticles (γ-Fe₂O₃ NPs) were synthesized using Massart procedure. The formation reaction were optimized by varying the concentration of ferric nitrate solution (Fe(NO₃)₃) (0.1, 0.3, 0.5, 0.7 and 1.0 M). All samples were characterized by means of x-ray Diffractometer (XRD), Raman Spectroscopy, Transmission Electron Microscope (TEM) and Alternating Gradient Magnetometer (AGM). The smallest size of the NPs were chosen to be deposited on Silicon (100) substrate by spin coating technique. Annealing process of the samples were performed in Argon ambient at different temperatures (600, 700, 800 and 900°) for 20 min. Metal-oxide-semiconductor capacitors were then fabricated by depositing Aluminium as the gate electrode. The effect of the annealing process on the structural and electrical properties of γ-Fe₂O₃ NPs thin film were investigated. The structural properties of the deposited thin film were evaluated by XRD analysis, Atomic Force Microscopy (AFM) and Raman Analysis. On the other hand, the electrical properties was conducted by current-voltage analysis. It was revealed that the difference in the annealing temperature affect the grain size, surface roughness, distribution of the nanoparticles as well as the electrical performance of the samples where low annealing temperature (600 °C) gives low leakage current while high annealing temperature (900 °C) gives high electrical breakdown.

Lanthanide magnesium hexaaluminate (LaMgAl₁₁O₁₉) powders were successfully synthesized by the solid-state reaction method. The objective of this study was to investigate the synthesis mechanism of LaMgAl₁₁O₁₉ and prepare LaMgAl₁₁O₁₉ powders suitable for plasma spraying. The results show that LaAlO₃ reacts with MgAl₂O₄ and Al₂O₃ to form LaMgAl₁₁O₁₉ at approximately 1300 °C. Single-phase LaMgAl₁₁O₁₉ powders were prepared successfully by solid-state reaction at a synthesis temperature of 1600 °C for 6 h. Unlike the particles in the synthesized powders, those of the centrifugally spray-dried powders have a spherical shape with uniform granularity and good flowability, density, and particle size distribution, making them suitable for plasma spraying. The synthesized powders and centrifugally spray-dried powders remained as a single phase after heat treatment at 1300 °C for 100 h, indicating that LaMgAl₁₁O₁₉ has excellent high-temperature stability.

This paper highlights an investigation on the comparative analyses of exergetic performance with optimum volume concentration of hybrid nanofluids in a plate heat exchanger (PHE). Different types of hybrid nanofluids (Al₂O₃ + MWCNT/water, TiO₂ + MWCNT/water, ZnO + MWCNT/water, and CeO₂ + MWCNT/water) as coolant have been tested. Proportion of 0.75% of nanofluid has been found to be the optimum volume concentration. The requisite thermal and physical properties of the hybrid nanofluids were measured at 35 °C. Various exergetic performance parameters have been examined for comparing different hybrid nanofluids. The highest reduction in exergy loss of CeO₂ + MWCNT/water hybrid nanofluid has been obtained at a concentration of about 24.75%. Entropy generation decreased with the increase in volume concentration. The results established that CeO₂ + MWCNT/water hybrid nanofluid can be a promising coolant for exergetic performances in a PHE.

First-principles calculations are performed to study the dual effect of spin orbital coupling and electric fields on the structure and electronic properties of stanane (hydrogen saturated stanene). For the relaxed configurations, it is found that spin orbital coupling effect has little impact on the geometry of stanane. However, the total energies of the stanane under electric fields are decreased. We also found that the transferred charge is mainly accumulated around the hydrogen atoms, indicating tin atoms are the charge donor in stanane. Linear response calculations prove the phase stability of stanane. Our results also indicate that the fundamental energy gap in stanane can be tuned by electric fields.

In this study, Titania nanorods were synthesised from aqueous extract of Turbinaria conoides (brown seaweeds) (TiO₂NRs-TC) under surfactant free medium. The photocatalytic activity of the synthesised nanorods was tested towards the photocatalytic decolourization using simulated dye wastewater containing Navy Blue HER (NBHER). The synthesised Titania nanorods were characterized by using x-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrophotometer (EDS) and Transmission Electron Microscopy (TEM). XRD pattern confirms the anatase phase formation and HR-SEM micrograph shows the presence of rod like structure with the size of about 50 nm. TEM analysis proves the rod like structure with a size of 45–50 nm which was in agreement with the XRD analysis and HR-SEM images. EDS and XDS confirmed the formation of Titania nanoparticles. The formation of TiO₂NRs-TC has a beneficial influence on the dye Navy blue HER photodegradation. TiO₂-TC nano rods also show superior photocatalytic ability in hydrogen generation (2.1 mmol/h⁻¹g⁻¹). The antibacterial activity of the synthesised nanoparticles was examined using disc diffusion method which showed diverse susceptibility of microorganisms to the Titania nanoparticles.

The crack-tip displacement field and molecular dynamics finite element method with Tersoff potentials were used to find the mode-I stress intensity factors (SIF) of silicene, aluminum nitride (AlN), and silicon carbide (SiC) hexagonal sheets. Fracture properties of graphene and boronitrene are also included for comparison. It is found that K_Ict (K_Ic is mode-I critical SIF and t is the sheet's thickness) of silicene, AlN, and SiC sheets are approximately 80, 66, and 47%; and 73, 64, and 45% smaller values of those of graphene for crack along the armchair and zigzag directions, respectively. The estimated fracture toughness of silicene is close to the experimental data of single-crystal silicon.

Zn_0.96-xMn_0.04Sn_xO (x = 0, 0.02, 0.04) were synthesized using Phyllanthus Niruri leaf extract mediated co-precipitation method. The x-ray diffraction pattern demonstrates that doping of Mn and Sn did not show any variations in the ZnO hexagonal wurtzite structure. The reduced crystallite size by Sn doping is because of lattice distortion that altogether prevented the growth. The variations in lattice parameters, average crystallite size, peak position and peak intensity from XRD in addition to EDX, FTIR and optical studies supports the substitution of Sn²⁺ into Zn-Mn-O lattice. The presence of chemical bonding was studied by FTIR spectroscopy. The optical absorption and band gap alterations with respect to Sn doping were investigated by UV-Visible spectroscopy. The widening of band gap by Sn doping is attributable to both size and compositional effects. The dielectric properties, conductivity and antibacterial properties are boosted up with the addition of the Co-dopant Sn to 4%.

AuAg nanoclusters (AuAgNCs) with high fluorescent was synthetize. The fluorescence of the AuAgNCs was quenched by thiocholine (TCh), a product of the catalytic hydrolysis of acetylthiocholine (ATCh) by acetylcholinesterase (AChE). In the presence of paraoxon (a AChE inhibitor), the catalytic hydrolysis of ATCh was blocked, and then the fluorescence of the AuAgNCs was retained to some degree. Based on this mechanism, the AuAgNCs with high fluorescence was first time used to detect the AChE and AChE inhibitors. Under the optimal conditions, the linear range of this method for AChE was 0.4–25 mU/mL with the detection limit of 0.15 mU/mL, which compare favorably to previously reported methods with more widely linear range or much lower detection limit. And for the detection of paraoxon, the corresponding IC₅₀ was estimated to be 1.9 ng/mL. This method was also utilized to detect the paraoxon in apple samples successfully. This study provides a new selective and sensitive fluorescent assay for determination of AChE activity and AChE inhibitor, and expands the application of AuAgNCs in biological analysis.

Well-crystallized cadmium telluride quantum dots (CdTe QDs) were fabricated by a simple wet chemical process under open air condition at a growth temperature of 100 °C. Various amounts of the capping ligands were used in order to study the effects of them on the structural, optical and luminescence properties of C dTe QDs. The structural properties were studied using x-ray diffractometer (XRD) and scanning electron microscope (SEM). All the as-obtained CdTe QDs displayed a zinc blende crystal structure with no extra phases observed in the XRD analysis. The diffraction reflection intensities were enhanced with an increase in the capping ratio with the optimum condition achieved at a capping ratio of 1.2. The average particle sizes estimated from various techniques increased with an increase in the amounts of capping ligands used (2.14, 3.19, 2.75, 3.00, 3.27 and 4.47 nm for 0.8, 1.0, 1.4, 1.6 and 2.0 capping ratio). The SEM analysis revealed spherical shaped CdTe QDs with string-like features covering the surface of the QDs observed at higher capping ratio. Aggregation of the CdTe QDs was observed for the QDs prepared at a lower capping ratio (Cd:Cyst of 1:0.8). The Photoluminescence (PL) studies displayed a red shift in the emission wavelength accompanied by variation in the emission peak intensity. The emission wavelength shifted from 558–571 nm for 0.8–2.0 capping ratio. Highest PL emission peak intensity was obtained at a capping ratio of 1.2 which was in line with the results obtained from the XRD. The absorbance of the as-prepared CdTe QDs increased while the band gap decreased with increasing capping ratio due to the growth of the QDs.

The paper presents the synthesis and characterization of zinc oxide (ZnO) nanoarrays on carbon fiber fabrics using the combined atomic layer deposition (ALD) and hydrothermal methods. A conformal ZnO seed layer was first synthesized using the ALD method on carbon fiber surfaces, then characterized by field emission scanning electron microscope (FESEM). ZnO nanoarrays were grown on the carbon fibers using the hydrothermal method. The morphology of ZnO nanoarrays in the form of nanowires and nanorods was controlled by adjusting hydrothermal synthesis parameters, including the concentration of chemical reagents and solution temperature. The FESEM characterization showed that the synthesized ZnO nanowires and nanorods had a wurtzite structure and uniformity distributed on the surface of carbon fibers. The length to diameter ratios of the ZnO nanoarrays were controlled between 44 and 270. The thermogravimetric analysis tests showed that the growth of ZnO nanoarrays added about 10% additional weight to the carbon fibers.

Nickel oxide (NiO) nanoparticles was prepared using top-down method in the size range 12–70 nm via ball milling of their bulk. Bulk size NiO was prepared by heating of Ni(NO₃)₂.6H₂O in air. This NiO powder was then milled in planetary ball mill keeping a fixed powder to ball ratio. Strain was introduced in the powder during milling process. The structure of milled samples was studied using x-ray diffraction (XRD) while Vibrating Sample Magnetometer (VSM) measurements were carried out to study magnetization in samples. The peaks in the x-ray diffraction (XRD) pattern correspond to pure NiO phase showing no trace of any other phase. Strained particles showed higher magnetization as compared to relaxed NiO nanoparticles. Positron Annihilation Coincidence Doppler Broadening (PACDB) spectroscopy was used to study the 3d and core electron momentum distribution in the vicinity of Ni atom. It is observed that as milling proceeds and the particles become more and more laminar the positrons get annihilated preferentially at the oxygen core. A relation between PACDB quotient ratio and mechanical strain is established in this study.

Poly(vinylidene fluoride) (PVDF) membranes were blended with loading different kinds of carboxylated multi-walled carbon nanotubes (MWCNTs) by phase inversion method. PVDF with different molecular weight of 450 and 800 kDa was selected for our study, whereas four CNTs as pristine multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes with different carboxyl content from 0.49, 2 to 3.86 wt.% were chosen for a comparison. The casting solution was set as 18 wt%. The effects of carboxyl content in MWCNTs and molecular weight of PVDF on membrane morphology, surface roughness, surface hydrophilicity, pore size and porosity were comprehensively investigated by field emission scanning electron microscope, atomic force microscopy, water contact angle measurements, the Brunauer–Emmett–Teller and the gravimetric method. The crystallinity, thermal and mechanical properties of different membranes were evaluated by x-ray diffractometer, differential scanning calorimetry and single-fiber electronic tensile tester. With the increase of carboxyl content in MWCNTs, the thermal stability of composite membranes was enhanced to some degree and the crystal transformation was slightly altered. The results indicated that the composite membranes containing carboxyl content of 0.49 wt.% in MWCNTs and higher molecular weight of PVDF possessed better mechanical properties, higher hydrophilicity and more preferable morphology, which have great significance in fundamental researches as well as the application of composite membranes.

The electronic and magnetic properties of carbon nanobuds have been investigated using density functional theory. The carbon nanobuds are formed by attaching smaller fullerenes (C₂₀, C₂₈, C₃₆ and C₄₀) of variable size with (5, 5) ACNT and (5, 0) ZCNT. Fullerenes interact strongly with CNT surface having binding energies within the range −0.93 eV to −4.06 eV. The C–C bond lengths near the attachment region increase from the original C–C bond lengths. The relative stabilities of the nanobuds are closely related to C–C bond lengths and bond angles in cycloaddition reaction. Nanobuds formed by bond cycloaddition are energetically most favorable amongst all cycloadditions. The electronic and magnetic properties of nanobuds depend strongly on electronic properties of its building blocks. The attachment of C₂₀ and C₄₀ on CNTs open up the HOMO-LUMO gaps of nanobuds whereas C₂₈ and C₃₆ results in addition of impurity states near the Fermi level. The total magnetic moment of nanobuds vary from 0.28μ_B to 4.00μ_B which depend on the nature of bonding between fullerene and CNTs. The results outline the potential of nanobuds as hybrid carbon nanostructures and how their properties can be tuned with the size and type of fullerene attached.

The spherical KBi(MoO₄)₂ nanoparticles were first prepared by solvothermal process. The crystal structure and morphology of KBi(MoO₄)₂ nanoparticles have been determined by x-ray diffraction (XRD), scanning electron microscopy (SEM), BET specific surface area and pore size analysis. The KBi(MoO₄)₂ nanoparticles are uniform spherical and crystalized in tetragonal scheelite structure with average size about 20 nm. The specific surface area of the KBi(MoO₄)₂ nanoparticles is 32.4 m² g⁻¹. The KBi(MoO₄)₂ nanocrystallite is an n-type semiconductor. The sensor based on KBi(MoO₄)₂ nanocrystallites shows gas sensing to ethanol and n-butanol with rapid response and recovery.

In the present work, we perform ab initio nonadiabatic molecular dynamics to investigate the charge carrier relaxation dynamics in pristine, boron doped and nitrogen doped graphene quantum dots, respectively. Heteroatom doping changes the local bonding environment of carbon atoms, and induces the charge trapping states into the band gaps of boron doped graphene quantum dot (BGQD) and nitrogen doped graphene quantum dot (NGQD), respectively. Elastic electron-phonon energy exchange destroys the electronic coherence of charge trapping states resulting in a slower electron trapping in BGQDs and a slower hole trapping in NGQDs, respectively, which indicate the high electron mobility of BGQD and high hole mobility of NGQD. In addition, our calculation results suggest the slow and asymmetric electron and hole relaxations of BGQDs are beneficial for both oxidation and reduction reactions for water splitting, while the slower electron relaxation than hole relaxation promises NGQDs the oxidation activity for catalyzing the water splitting. Our work can be used to guide the chemical modification of electronic structures of graphene based QD materials.

The cobalt ferrite (CoFe₂O₄) nanoparticle sensors, synthesized using cost-effective sol-gel auto-combustion method, are irradiated with 2 and 5 kGy γ-doses. Effect of γ-irradiation on the structure, morphology and porosity is studied initially and in the later stage, methanol, acetone, ammonia, ethanol and toluene volatile organic gases are exposed for monitoring their selectivity and sensitivity with pristine and γ-irradiated CoFe₂O₄ nanoparticle-pellet sensors. The 5 kGy γ-irradiated CoFe₂O₄ sensor reveals 70% response for ammonia (100 ppm) gas, with high selectivity and room-temperature chemical and environmental stabilities. For knowing the changes in the structure, morphology, porosity and gas sensing performance of CoFe₂O₄ sensors on γ-irradiation theoretical model has also been proposed and explored. Proposed γ-irradiation approach can be used for enhancing the sensitivity of other gas sensors at room-temperature.

Issues associated with the dry spinning process were explored and addressed in this paper. Post-treatment of dry-spun Carbon Nanotube (CNT) fibers frequently includes solvent densification. This procedure was modified in our work to enhance mechanical strength of the fiber. The effect of n–Methyl-2-Pyrrolidone (NMP) as a densifying solvent was studied at different temperatures within the range of 23 °C–153 °C. High temperature densified fibers revealed better load bearing (40% increase) and higher density compared to room temperature values, which translated to higher tensile strengths (1.2–1.3 GPa). A maximum tensile strength of 1.5 GPa was achieved with resistance assisted heating combined with NMP heating. However, all these properties, including the fiber diameter, varied depending on the position within the array from where the fibers were drawn. This was attributed to a gradation in the length of the CNT's along the location of the drawing area within the array. Improved fiber uniformity was achieved by drawing from opposite ends of CNT arrays simultaneously. This study enabled to improve the densification process and addressed a major fiber uniformity problem accompanying the dry spinning method.

In the developing era, metal oxide nanomaterials are intensively pursued due to their prominence applications in different applied and technological fields. The transition metal oxide, copper oxide is a dominant candidate for magnetic storage devices, sensor, and solar energy transfer as a heat absorber, super capacitors and mainly as a good catalyst in chemical reactions. Here, CuO nanostructures with different shapes (nanoparticle, cubelike, rectangular, nanobar and nanorod) are synthesized by precipitation method from CuCl₂ precursors. The CuO all structures are characterized by X-ray diffraction for the structural study. CuO different shapes morphological phenomena are carried out from SEM and TEM. The thermal properties are calculated by recording thermo-curves, viz. thermogravimetric (TG), differential thermogravimetric (DTG). Thermogravimetric analysis revealed CuO all structures show weight loss at 340 K to 380 K and 1000 K to 1250 K region because of water evaporation and combustion of organic compounds respectively. Activation energy, Arrhenius factor, activation enthalpy, activation entropy and Gibbs free energy for the decomposition of CuO were determined using the Coats-Redfern (CR) method for all shaped structures.

The properties of Au₃₂ clusters through selective doping with Si, Ge and Cu atoms and its interaction with CO₂ molecule are reported in this work. The relative stabilities of the clusters compared on the basis of average binding energy per atom indicated that Cu₁₂Au₂₀ is stable with a binding energy of −86.085 kcal mol⁻¹/atom. A charge density-based analysis of the doped clusters is also presented. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap of M₁₂Au₂₀ cluster (M denotes dopants) is much smaller, compared to that of the Au₃₂ cluster, implying higher reactivity. Molecular electrostatic potential (MESP) and its analysis gave guidelines to the various possible sites for the adsorption of CO₂ molecule. The most favourable dopant for CO₂ adsorption was found to be Cu amongst all the others. Calculated Infrared (IR) frequencies indicate that Cu-doped gold clusters give maximally intense peaks for CO₂ stretching. Absorption spectra of the nanocages are also presented using time-dependent density functional theory (TDDFT). This has maximum change in wavelength for Si-doped cluster on CO₂ adsorption. The structural and band gap changes are manifested in the catalytic properties with the result that the doped cages showed strong adsorption for CO₂ as compared to pristine Au₃₂ cluster, with Cu being the best doping agent.

Luminescence tunable graphene oxide-europium (GO-Eu) composites were obtained by adopting a fresh composite preparation procedure. Unique GO-Eu precursor compositions maintained in acidic pH range and subjected to ultrasonic treatment were found to exhibit fine tuned emission bands ∼600 nm. FT-IR, XPS and SEM studies evidence the uptake of Eu ions in composite sheets and denote their nature of bonding with various functional groups at multiple sites of GO. Initial interaction of Eu ions with GO involves both adsorption as well as bonding processes while, introduction of acidity and ultrasonic treatments hinder the instant aggregation of composite sheets and facilitate the complexation of Eu ions at most reactive sites of GO. Changes in heterogeneous electronic structure of composite sheets alter the relative intensities of radiative transitions from localized states associated with and cause the observed fine tuning of luminescence from composites. These inferences were assessed by examining the emission features of aged GO-Eu composites exposed to different pH and ultrasonic treatment conditions. Distinctive windows of parameters were proposed to achieve relatively narrow and fine tuned emission bands in the wavelength range of 550–750 nm using fresh and aged GO composite dispersions.

Here, SnO₂ nanoribbons (NRs) synthetized on the catalyst-free stainless steel (SS) substrate as a possible anode for Li-ion batteries (LIBs) have been reported. SnO₂ NRs were synthesized on catalyst-free SS substrate via vapor-solid (VS) growth approach. Morphological and structural characterizations of the SnO₂ NRs were confirmed using scanning electron microscopy (SEM), transmission electron microscopy (TEM) microscopes and x-ray diffraction (XRD) respectively. The prepared binder-free electrode demonstrated high initial discharge/charge capacities of 1818/929 mAh g⁻¹ at current density of 300 mA g⁻¹. A reversible capacity of 676 mAh g⁻¹ with a coulombic efficiency of 98.5% has been achieved after 20 cycles. High specific capacity, superior rate capability and good cycling performance resulting from the SnO₂ NRs electrode propose this nanostructure as an excellent anode for advanced LIBs.

In recent years the unique properties of copper nanostructures are the subject of numerous studies in various areas of material science. In this paper, we studied the features of the electroless template synthesis of copper nanotubes (Cu NTs) in the nanoporous poly(ethylene terephthalate) track-etched membranes (PET TeMs) under various temperature deposition regimes. The structure and the chemical composition of the obtained composite membranes were studied by the methods of gas permeability, scanning electron microscopy, energy dispersive analysis and x-ray diffraction. The effect of deposition temperature on the catalytic properties of Cu NT in a polymer matrix was studied using the benchmark reaction of the reduction of p-nitrophenol (4-NP). The highest rate constant of the 4-NP reduction reaction was established for composites synthesized at 10 °C. This temperature regime of synthesis makes it possible to obtain strong thin-walled Cu NTs in the pores of PET TeMs and the 4-NP conversion degree after 6 consistent runs of the composite catalyst decreases by 20%, while for samples deposited at 25 °C the conversion index decreases by more than 40%. To study the kinetic parameters of the reaction in a temperature range of 16 °C–40 °C, the activation energies found from the Arrhenius plots were 35.3 and 61.3 kJ mol⁻¹ for the reaction over catalysts synthesized at the 2 and 25 °C, respectively, and 28.32 kJ mol⁻¹ for the samples deposited at the 10 °C. The results indicate a high potential of composite catalysts based on the PET TeMs with embedded copper NTs for 4-NP removal.

Water pollution is a serious environmental problem and coloured pigments are considered one of the greatest concerning contaminants. Graphene, a new two-dimensional material presenting high theoretical specific surface area, has been widely studied for applications in wastewater treatment. It was the aim of this work to study the feasibility of producing Graphene Oxide (GO) under different conditions, using Factorial Design techniques, so that it could be successfully applied in the adsorptive removal of Methylene Blue (MB) dye in aqueous medium. For GO production, the best conditions were achieved within 3 h of reaction and no ultrasonic bath, for a percentage removal of MB over 99%. Surprisingly, it was verified that ultrasonic bath and the increase in reaction time had negative effects under GO production process. For the adsorptive studies using the best samples produced, it was observed that the best pH value was 5.5, and the maximum adsorptive capacities predicted by the Langmuir model were approximately 365 and 504 mg.g⁻¹, although this was not the model that best fit the experimental data. Unlike most previous works which reported MB adsorption onto GO occurs in mono-layers, in this study it was proved the process happens with formation of multiple layers, as the equilibrium data best fit the Temkin model. Both the physical nature and the spontaneity of the process were verified by the Gibbs free energy of adsorption. Equilibrium was reached very quickly in less than 10 min, and kinetics data were properly fitted to pseudo-second order model.

Green synthesis of CuO nanospindles and their assembly into nanoflowers has been demonstrated by changing the solvents such as water and ethanol along with the Dodonaea angustifolia (DA) extract. This is the first to report the use of DA extract for the green synthesis of nanostructures. The DA+water yielded the nanospindles of CuO, while DA+ethanol led to the assembly of nanospindles into nanoflowers as confirmed from their electron microscopy images. The Fourier-transform infrared spectrum of the extract and CuO revealed that the DA led to the phase formation and capped the CuO nanostructures. The antimicrobial activity against E. coli and S. aureus bacteria was found to be enhanced for CuO nanoflowers as compared to nanospindles. Based on the results, the mechanism for the formation and anti-microbial activity of the CuO nanostructures have been proposed.

In this paper, water-soluble nitrogen doped fluorescent carbon dots (N-CDs) have been prepared by a facile hydrothermal treatment of bagasse waste and urea. The prepared N-CDs were characterized by high resolution TEM, fluorescence spectroscopy, FTIR and x-ray photoelectron spectroscopy. The results revealed that the prepared N-CDs were mainly composed of hydroxyl, carboxyl and amino groups with an average size of ca. 5.0 nm. The prepared N-CDs exhibited excellent photoluminescence and emitted light blue fluorescence under a 365 nm UV light. Owing to the selective fluorescent quenching response of Hg²⁺, the prepared N-CDs have been used as a fluorescent probe for sensitive detection of Hg²⁺ in water. The fluorescent quenching mechanism could be due to the special coordination interaction between Hg²⁺ and the surface functional groups of the fluorescent N-CDs. Meanwhile, the fluorescence quenching efficiency decreased linearly with Hg²⁺ in the concentration range of 0.005–0.8 μM. The detection limit is low to 0.002 μM. The synthesized N-CDs were further applied to the detection of Hg²⁺ in real water samples.

Transparent conducting indium tin oxide (ITO) nanoparticles were synthesized by plasma-assisted chemical vapor synthesis route using indium nitrate and tin nitrate as the precursors. The injected precursors were vaporized in the plasma flame followed by vapor-phase reaction and subsequent quenching of the vaporized precursors produced nanosized ITO. The amount of tin nitrate was varied to obtain 5, 10 and 15 atomic percent Sn designated as ITO1, ITO2 and ITO3, respectively. The grain size of the produced ITO powder increased with increasing plasma torch power. On the other hand, it decreased with increasing plasma gas flow rate. The electrical and optical properties of ITO films prepared by spin-coating a dispersion of synthesized nanoparticles on a glass substrate vary as a function of tin content. Hall effect measurements showed that the minimum resistivity of 6.65 × 10⁻⁴ Ωcm was obtained for ITO2 film. ITO1 and ITO2 film exhibited an average transmission of 85% indicating their suitability in optoelectronic applications. The ITO gas sensor was exposed to different concentrations of H₂ gas and temperatures to evaluate its gas sensitivity. The optimum operating temperature and gas concentration of H₂ showing the highest sensitivity was determined to be 350 °C and 400 ppm, respectively. The linear relation between sensitivity and concentration up to 400 ppm of H₂ can benefit the actuator to detect the concentration of H₂ and thus making it suitable for high-performance hydrogen gas sensing applications.

Since SF₆ has a very high global warming potential, it is essential to replace SF₆ with environmentally friendly insulation gas. However, most readily available insulation gases have low electrical breakdown strength, which needs to adopt additional insulating means to enhance the poor breakdown strength. In this paper, with the aim of improving breakdown strength, filler/epoxy (EP) composites with nano-SiO₂ particles in the weight percentage range of 0–5 wt% are used as dielectric coating materials and N₂ is applied as insulating gas. As compared to that of neat EP, there is a decline in permittivity of SiO₂/EP nanocomposites in the frequency range from 10^–2 to 10⁶ Hz. Moreover, for SiO₂/EP nanocomposites, the permittivity increases at first and then decreases as the filler content increases. With respect to the gas-coating insulation system, 50% breakdown voltage (BDV) U₅₀ of the electrode with pure EP dielectric coating material is larger than that of bare electrode. Furthermore, a better BDV performance is obtained when applying SiO₂/EP nanocomposites as dielectric coatings, indicating the introduction of SiO₂ nanoparticles into EP matrix can reinforce the property of epoxy. The maximum BDV of 93 kV occurs in the electrode with 3 wt% SiO₂/EP coating material, which is 29.17% higher than that of bare electrode. Additionally, it is found that the permittivity of coating material has a significant influence on the breakdown performance since it can alter the electric field distribution, and a lower permittivity always gives rise to a higher BDV.

In order to research the optical properties of negative electron affinity (NEA) GaAs nanowire photocathodes, (10-10) surface models of clean wurtzite GaAs nanowire and nanowires adsorbed by one Cs, two Cs, three Cs and four Cs atoms are established. Band structures, density of states, dielectric function, absorption spectrum, reflectivity spectrum, complex refractive index and loss function for different Cs adsorption models are investigated utilizing first-principles. Results show that with increasing surface Cs coverage, the band gap of GaAs nanowires gradually disappear and surfaces exhibit semi-metal characteristic. The average values of reflectivity spectrum for Cs atoms adsorbed GaAs nanowire models are all less than that of clean surface, which makes the incident photons come across the Cs-adsorbed surfaces easier and excite more photoelectrons. During the energy range from 0 eV to 2.2 eV, the absorption coefficients for different Cs adsorption models are all larger than that of the clean one, indicating that Cs atoms can enhance the optical absorption properties of wurtzite GaAs nanowires material. All calculations in this study can give a theoretical guidance for the preparation of NEA GaAs nanowire photocathodes.

Present communication deals with study of effect of SHI irradiation of 100 MeV oxygen ions on the electrochemically synthesised polyaniline (PANI)/single walled carbon nanotube (SWNTs) composite electrode. PANI/SWNTs composite was used for the modification of stainless steel electrode. The composite was irradiated with fluences 1 × 10¹⁰ ions cm⁻², 1 × 10¹¹ ions cm⁻² and 1 × 10¹² ions cm⁻² of oxygen ions having energy 100 MeV. Electrochemical techniques viz. cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electroactive nature of composite before and after irradiation. Morphological study was carried out using Field Electron Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). Composite matrix irradiated with fluence 1 × 10¹⁰ ions cm⁻² had shown good electroactive nature and therefore was used for analytical application viz. electrochemical detection of divalent cobalt ions. The irradiated PANI/SWNTs composite was modified by chelating ligand viz. dimethylglyoxime (DMG) to ensure the selectivity of metal ion viz. Co(II). The electrode (DMG modified SHI irradiated PANI/SWNTs composite) could detect the lowest concentrations to 0.355 μML⁻¹ or 0.1 mgL⁻¹ which is equal to Maximum Contaminant Level (MCL) of cobalt ions proposed by US EPA. The analytical behaviour of electrode has proved the SHI irradiation as suitable tool for modification of organic conducting polymers (OCP)/SWNTs composite.

Titanium dioxide nanoparticles have shown a tremendous potential in various fields such as photocatalysis, solar-photovoltaics, electrodes, sensors, implants and pigments. Due to these versatile applications, their synthesis routes have gained a vast attraction and demand for being frugal and eco-friendly with better control over the anatase and rutile phase ratio. Comprehensively, the sol-gel method is a widely used technique for the synthesis of TiO₂ nanoparticles that requires several additional chemical entities such as organic solvents, acids and capping agents. It makes this process quite uneconomical and hazardous in nature. In the present study, non-hazardous microwave and/or ultrasound based one-pot synthesis approaches have been studied for the production of phase controlled TiO₂ nanoparticles and compared with the sol-gel synthesized and commercially available TiO₂ nanoparticles. These comparisons have been validated through several material characterization techniques. The obtained results have shown that the ultrasound based synthesis followed by suitable thermal processing alone has tremendous potential to produce phase controlled TiO₂ nanoparticles (preferably anatase phase), mostly in the form of nano-micro aggregates. In addition, the photocatalytic activity of ultrasonically synthesized TiO₂ nanoparticles has also been examined and compared with that of the commercially available TiO₂ nanoparticles. It is interesting to observe that, ultrasonically synthesized TiO₂ nanoparticles have not only shown improvised photocatalytic degradation activity, but also shown a significant improvement on their separability and recyclability for water treatment applications, in comparison to that of the commercially available TiO₂ nanoparticles (TiO₂-P25).

Since the grain size and microstrain amounts in the microstructure affects the final properties, studying the effect of annealing parameters on grain size and microstrain using experimental data and statistical models is important for designing strong metals. In this work, nanostructured Cu powder prepared by high-energy ball milling was annealed at various conditions. The effects of annealing time and temperature on the grain size and microstrain were investigated using response surface methodology. X-ray diffraction was conducted to measure the grain size and microstrain. In addition, scanning electron and transmission electron microscopies were used to characterize the produced powder. The results showed that the models were predicting the responses, accurately. The annealing temperature was the most effective parameter to minimize the microstrain as a result of concurrent existence of recovery, recrystallization, and grain growth. The developed models can be used for predicting grain size and microstrain, and therefore they can be accepted as an economical way to extract arbitrary information about grain growth kinetics of annealed Cu nanostructured powders.

The novel properties of carbon nanotubes have generated much interest in nanostructured polymer composite materials. The effect of multi-walled carbon nanotube aspect ratio on the thermal and electrical properties of nanostructured epoxy composite materials was investigated both experimentally and theoretically. Both thermal and electrical conductivity measurements were performed, and comparisons were made between the results obtained for the nanostructured composite materials containing carbon nanotubes with different aspect ratios. Potential applications of these nanostructured composite materials were discussed, and design recommendations were also made. The numerical and experimental results indicated that the aspect ratio plays an important in determining the physical properties of the nanostructured epoxy composite materials. The electrical conductivity of the nanostructured composite materials is highly dependent on the aspect ratio of carbon nanotubes. In contrast, the aspect ratio plays a considerable role in the thermal conductivity of the composite materials. Multi-walled carbon nanotubes are capable of improving both thermal and electrical performance of the polymer matrix. In contrast to the orders of magnitude enhancement in electrical conductivity with a very low loading of carbon nanotubes, the thermal conductivity of the composite materials has shown only moderate improvement. The improvement in physical properties of the composite materials can be interpreted in terms of carbon nanotube networks.

Doping wide bandgap (∼3.0 eV) CuSCN with Fe impurity become favorable to absorb visible spectrum and converts its p type properties into n type. The Solid state cell made from Fe doped n-CuSCN and p-Cu₂S shows a remarkable photocurrent due to the formation of p-n junction for the first time. Here Fe doped CuSCN layer is fabricated by immersing a well cleaned Cu plate in a solution containing of 0.2 M KSCN and 0.005 M FeSO₄ for 18 h and p-Cu₂S layer is fabricated by immersing in a 0.0001 M aqueous (NH₄)₂S solution. The materials characterization of the fabricated samples are studied using Scanning Electron Microscopy (SEM), Energy Dispersive X ray (EDX) patterns, Fourier Transform Infrared (FTIR) spectra and X ray Diffraction (XRD) patterns.

Adsorption rate is one of the key indicators to evaluate the adsorption performance of a nanomaterial. Herein, nanosized rod-like HAP particles were prepared via a facile hydrothermal process by using guanidine phosphate as the phosphorus source. HAP nanoparticles show a rough surface and a high BET surface area (82.94 m² g⁻¹), and display an excellent adsorption rate for the removal of congo red (CR) dye in aqueous solution with a maximum adsorption capacity of 337.330 mg g⁻¹. Thus, this kind of HAP nanoparticles can be used as an efficient, fast and low-cost adsorbent for the treatment of industrial effluents contaminated with similar anionic dyes.

We report the melting temperature of free-standing silicene by carrying out molecular dynamics (MD) simulation experiments using optimized Stillinger-Weber (SW) potential by Zhang et al (2014 Phys. Rev. B89 054310). The melting scenario of a free-standing silicene is well captured visually in our MD simulations. The data are systematically analyzed using a few qualitatively different indicators, including caloric curve, radial distribution function and a numerical indicator known as global similarity index. The optimized SW potential consistently yields a melting temperature of 1500 K for the simulated free-standing, infinite silicene.

W-doped monoclinic VO₂ nanoparticles were synthesized using a hydrothermal method. The phase transition temperature of these nanoparticles was lowered to approximately 26 °C when doped with 2 at% W. The temperature reduction efficiency was found to be −22 °C/at% W. An annealing process was used to improve phase transition performance of doped VO₂ samples. The latent heat of the phase transition for the doped VO₂ sample increased at higher annealing temperatures, and it was comparable to that of undoped VO₂ when annealed at 950 °C. This work showed that the phase transition performance of doped VO₂ was improved following annealing and the phase transition temperature could remain relatively low. Additionally, annealing was found to eliminate the amorphous VO₂ coating that surrounded the VO₂ particles and enhance the crystallinity of doped VO₂, which led to the recovery of the transition performance of W-doped VO₂.

Nanorods, nanocubes and nanospheres of Nickel Ferrite were synthesized by the solvothermal route by using different ratios of water and ethylene glycol. The surface morphology of the nanorods, nanospheres and nanocubes was studied by Transmission Electron Microscope and their diameter was ∼40 nm, ∼50 nm and ∼80 nm respectively. The role of the solvent in controlling the shape of the particles was investigated. The sensitivity of the particles to LPG, Ethanol, Methane and Carbon Monoxide gas was investigated at different operating temperatures (100 °C–250 °C). The nanorods exhibit significantly high response towards liquid petroleum gas (LPG) in comparison to other gases. The maximum sensitivity of the nanorods for 200 ppm concentration of LPG was 0.687 at 200 °C. Nanorods also showed a remarkable response and recovery time of 114 s and 18 s. All the samples were also found to be reversible type sensors which makes them all the more suitable for applications. Hence these nanorods of Nickel Ferrite are expected to be useful in industrial applications as a potential LPG sensor. Porosity and specific surface area of the samples were studied to relate the change in sensitivity from sample to sample with the change in morphology. All the samples were found to be highly selective towards LPG. The sensing mechanism was also discussed in details.

Temperature is an important factor in operation of plasmon-based devices in terms of optical enhancement and system stability. However, systematic study, especially for the experimental validation for the quantitative analysis of quantum efficiency in optical enhancement is still lack of investigation. In this work, the ordered array of Au nanorods is fabricated on silicon and the Raman enhancement of this SERS (Surface Enhanced Raman Scattering) substrate is systematically investigated experimentally for its temperature-dependent characteristics combined with physical explanations through electromagnetic simulations. The SERS substrate shows significant Raman enhancement of silicon signal over the temperature range of 293 to 424 K. It is found that as temperature is increased, Raman intensity of both bare silicon and SERS substrate is decreased with different slope of 0.0020/K and 0.0026/K, respectively. Besides, it is found that a temperature rise of 130 K results in a decrease of 10.2% in Raman enhancement ratio, agreeing well with calculated value (28.6%) of Raman enhancement factor as the maximum predicted range for perfect theoretical structure. The temperature dependence of Raman shift (the slope) does not differ much. However, the photon frequency of inelastic scattered light for both substrates is different at room temperature (0.35 cm⁻¹) which is possibly attributed to the existence of residual stress in SERS substrate. The findings in this work are beneficial to understand the Raman enhancement at elevated temperatures, especially for applications in photovoltaic applications.

Addition of carbon nanofibers (CNFs) in cement composites is an effective method to improve the toughness and crack control capacity. However, the dispersion and influence mechanism of CNFs in cement composites remained some difficulty and controversy. The cement composites mixed with CNFs of good dispersion were well prepared by means of dispersant and ultrasonic treatment. Cement samples with different dosages of CNFs and varying W/C ratios were prepared for testing rheological property and mechanical strength. The results showed that the rheological parameters such as shear stress, viscosity and yield stress increased with the increase of shear rate and dosages of CNFs, while the opposite trend was observed when W/C ratio increased from 0.28 to 0.32. Meanwhile, compared with control sample, the compressive strength and tensile splitting strength of cement composites with 0.1 wt% CNFs increased from 95.2 MPa to 103.8 MPa, and 6.60 MPa to 7.38 MPa, with the increase of 9.0% and 11.8% by W/C of 0.30, respectively. And the microstructure analysis indicated that proper dosage of CNFs could effectively improve the pore structures and interface in cement composites due to nano-core effect, filling effect and bridging effect of CNFs.

The structural, electronic and magnetic properties of transition metals (TMs)-doped (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni and Cu) antimonene have been systematically investigated by first-principles density functional theory. The calculation results indicate that V, Cr, Mn, Fe, Co, Cu-doping induces the magnetic moment, Cr-doped antimonene exhibits diluted magnetic semiconductor property with the magnetic moments of 3 μ_B, and V, Mn and Co-doping induces a half-metallic characteristic. In addition, the biaxial strain can effectively modulate the band gap of TMs-doped antimonene. More importantly, the semiconductor property of Sc and Ti doping systems exhibit direct-indirect-direct transitions under external biaxial strain. Our works demonstrate that the intriguing and diverse properties of TMs-doped antimonene systems may manifest potential applications in nanoelectronics, spintronics and magnetic storage devices.

Ionic liquids are a kind of green solvent for CO₂ capture, and supporting ionic liquids on porous substrates can increase the interface area between ionic liquids and CO₂, decrease the gas diffusion resistance, and further reduce the ionic liquids consumption. In this study, the immobilization of ionic liquids [Bmim]BF₄ and [Bmim]Ac on SBA-15 were prepared with supercritical CO as solvent and ethanol as co-solvent. The traditional impregnation method was also compared. Results showed that the amount of CO₂ adsorbed both increased with the increase of ionic liquid loading, while the adsorption for supported ionic liquids prepared by supercritical CO₂ method was higher than that by impregnation method. With same ionic liquids loading amount, the supported ionic liquids prepared by supercritical CO₂ method had higher specific surface area and pore volume, and promoted the absorption of CO₂ accordingly. The supported ionic liquids were regenerated, which has been testified that the supported ionic liquids have well recycled stability for CO₂ adsorption.

Micro-nano structure of TaC dense ceramic material was prepared using a process of casting and heat treatment. The phase-composition, micro-morphology, crystal structure, and elemental distribution of the TaC dense ceramic were confirmed and analyzed using XRD, SEM, TEM, and EDS. Also, the hardness, elastic modulus, and facture toughness of the material were studied via nano-indentation and micro-indentation. The critical loads of the TaC dense ceramic were then discussed in terms of the two kinds of indentation methods. The results indicate that the hardness and elastic modulus of the TaC dense ceramic material are 28.51 GPa and 556.89 GPa, respectively. The critical load of the material cracking is between 400 mN and 450 mN, and the fracture toughness is 2.23 MPa · m^1/2 according to the nano-indentation method. The critical load of the material cracking is between 500 mN and 1000 mN, and the fracture toughness is 2.94 MPa · m^1/2 according to the micro-indentation method. The R-curve for the micro-nano structure of the TaC dense ceramic material is approximately a straight line, and the fracture toughness is a constant value about the nature of the material. There is crack deflection, grain bridging behavior, and a grain pull-out tendency in the crack propagation of the micro-nano structure of the TaC dense ceramic, and these prove that the fracture toughness of the micro-nano TaC dense ceramic is superior to that of the ordinary ceramic material.

The La_1−AAFeO₃ (A = Gd, Nd and Dy) nanoparticles were successfully prepared via micro-emulsion route. All the prepared nanoparticles were successfully characterized by various conventional techniques such as x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) etc. The grain size estimated from SEM image of the LaFeO₃ nanoparticles is between 50–161 nm. The lanthanide doped LaFeO₃ nanoparticles were subjected to dielectric behavior evaluation. The dielectric studies showed the improved dielectric behavior of Lanthanide-doped LaFeO₃ nanoparticles. Reduced graphene oxide was prepared via modified chemical route (Hummer's method). The prepared reduced graphene oxide was utilized to make the nanocomposites with as-prepared nanoparticles. The photocatalytic activity of LaFeO₃ nanoparticles and their composites with reduced graphene oxide was evaluated in the presence of visible light. Methylene blue was used as model organic compound for the photocatalysis studies. The UV-visible spectra of methylene blue recorded at various intervals showed the good photocatalytic activity of LaFeO₃- reduced graphene oxide nanocomposites.

To explore the efficient removal of dissolved organic pollutant molecules from water, multi-walled carbon nanotubes (MWCNTs)-polysulfone (PSF) composite membranes with high CNTs hybrid content were fabricated, and the adsorption and ultrafiltration behaviors towards bisphenol A (BPA) were explored in this study. The MWCNTs-PSF composite membranes were composed of a dense top surface and a porous bulk layer with MWCNTs separately embedding in or hanging on the polymer matrix. The pore size of the top surface centralized in 30–70 nm. The pure water flux of MWCNTs-PSF membranes was found to be variable in accordance with the surface pore size. The adsorption capacity of membranes towards BPA from water was remarkably enhanced by the composite of MWCNTs, and the maximum adsorption capacity of M-CNT15 was more than twice of that of M-PSF. In the filtration process, the MWCNTs-PSF composite membranes exhibited obviously superior retaining capacities to the neat PSF membrane. The M-CNT15 membrane maintained 20% rejection to BPA molecules in steady-state, comparison to nearly zero rejection of M-PSF under the same operating conditions.

The purpose of this research is to produce CMAS resistant YSZ based TBCs and compare thermal cycle performance of the TBCs before and after CMAS interaction. Plasma sprayed YSZ (Y), YSZ + Alumina (YA), YSZ + Titania (YT), and YSZ + Alumina + Titania (YTA) coatings have been exposed to CMAS at 1250 °C for 18 h. Thermal cycling tests were carried out with a propane + oxygen flame at 1250 ± 50 °C. Thermal cycle lifetime of YSZ, YA, YT, YTA, and CMAS contaminated Y, YA, YT, YTA coatings are 450, 416, 426, 438, 122, 211, 141, 298 respectively. After CMAS interaction, while the life span of other coatings has fallen to their life span's quarter, the life span of YTA coating has decreased slightly. Damages in the coatings after thermal cycle tests have been studied by using SEM to observe the microstructure and x-ray diffraction techniques to analyze the phase composition. Also to see areal distribution of the CMAS through the coating, EDS mapping has been carried out.

Using pseudopotential plane-waves method, we calculated the structural, elastic properties and hardness for layered ternary ceramic Ti₄AlN_2.89 in the pressure range from 0 to 200 GPa. The elastic properties were derived to discuss the stability and bonding composition of Ti₄AlN_2.89 under high pressure. It is observed that this crystal is stable in our studied pressure range, and there are four typical bonds in Ti₄AlN_2.89. They are Ti-N bonds, Ti-Ti, Al-Al and Ti-Al bonds, and Ti-N bonds are much stronger than Ti-Ti, Al-Al and Ti-Al bonds. In addition, we investigated the bond stiffness for Ti₄AlN_2.89 under high pressure and found its damage tolerance and fracture toughness is improved at high pressure. Besides, we employed a semiempirical method considering the role of metallic components to evaluate the hardness of this compound at different pressures. Results showed that the Vickers hardness of Ti₄AlN_2.89 increases as the pressure is increased. What's more, by calculating the Debye temperatures under high pressure, we found the melting point of Ti₄AlN_2.89 increases as the pressure is increasing. In a word, combined the results of mechanical properties with hardness and Debye temperature, we got the conclusion that the performance of Ti₄AlN_2.89 might be improved at a higher pressure.

The atomic parameters of metal ion-oxygen speciation such as bond-lengths and nearest neighbor distances for Ba-O, Te-O and O-O pairs, co-ordination numbers and bond angle distributions for O-Ba-O, O-Te-O and O-O-O linkages are determined by neutron diffraction and Reverse Monte Carlo simulations on the series of xBaO-(100-x)TeO₂ glasses containing 10, 15 and 20 mol% BaO. The glass network depolymerizes and the average Te-O co-ordination number decreases from 3.60 ± 0.02 to 3.48 ± 0.02 with increase in BaO concentration. Te-O bond lengths are in the range: 1.97 ± 0.01–1.92 ± 0.01 Å. Ba²⁺ is mostly in octahedral coordination and the Ba-O bond lengths are in the range: 2.73 ± 0.01 to 2.76 ± 0.03 Å. Te-O co-ordination number is also determined by Raman spectroscopy and it shows good agreement with the neutron data. The short-range structural properties i.e. metal ion coordination number (N_c) and bond lengths (d) were correlated with the stress-optic response. The bonding characteristic, B_r values were determined from the structural data of xBaO-(100-x)TeO₂ glasses and were used to predict the stress-induced birefringence properties.

Wide range of CdO—Na₂B₄O₇ glasses have been prepared and characterized via XRD, FTIR and UV spectroscopies along with DTA and ultrasonic techniques. The compositional dependence of the physical parameters such as the density, the molar volume, the optical transmittance, the optical band gap, the ultrasonic velocities and the elastic moduli on CdO content were determined. The profiles of XRD assured the amorphous nature of the explored glasses. The clarification of the borate and cadmium functional groups besides their linkages was extracted from the deconvoluted FTIR spectra. Such a clarification was used in the analysis of the relation of the mechanical, T_g and optical parameters versus CdO content. These physical parameters revealed the glass modifier role of CdO.

In the present investigation, we present our results on characterization of Ti joints, brazed with metallic glass ribbons of Ti₂₀Zr₂₀Cu₄₀Ni₂₀ alloy. Initially, metallic glass ribbons were produced using a vacuum melt spinner and used as filler materials for vacuum brazing of two Ti alloy plates at 967 °C for period of 10 min. Field-Emission Scanning Electron Microscopy (FESEM), the as-spun ribbons showed fully amorphous structure when examined on both surfaces by XRD and also verified by TEM investigation. The brazing joint of two Ti-plates using the metallic glass ribbon was found to be very sound. FESEM characterization of the cross-sectioned brazing joint shows sub-micron size grains uniformly distributed in the matrix with brighter appearance. EDX analysis revealed that the sub-micron grains are rich in Ti, while the matrix phase has Zr-enrichment. Back Scattered Electron (BSE) image also suggested substantial reaction of the brazing ribbon with Ti plates, whose typical lath microstructure is modified to nanostructured lamellar eutectic microstructure comprising of Ti-rich and Zr-enriched phases.

In present paper, bulk Se_78−xTe₂₀Sn₂Sb_x (x = 0, 2, 4 & 6) amorphous alloys were developed by melt quench technique. The synthesized samples were characterized by means of XRD and DSC techniques for structural and phase transformation analysis respectively. Hardness behavior was investigated by calculating Vickers hardness number and other thermo-mechanical parameters to examine the effect of Sb in Se-Te-Sn parent alloy.

Red mud glass-ceramic were prepared in this paper to analyze the effect of different crystallization temperatures (850 °C–940 °C) on crystallization characeristics, microscopic structure and surface reflectances of red mud glass-ceramic samples. The results show that, as the crystallization temperature rises up, the diffraction peak strength of crystalline phase is enhanced in common augite and diopside and the degree of crystallization is improved gradually. The crystalline grains are grown gradually and distributed evenly. The surface reflectances of red mud glass-ceramic samples under ultraviolet-visible-near infrared band are enhanced as the crystallization temperature rises. The surface reflectance is higher in visible light band and the reflection peak is found at 558 nm, the highest surface reflectance of 14.5% is found at crystallization temperature of 940 °C. The reflectances are found lower in near infrared band. The surface reflectances of red mud glass-ceramic samples under middle infrared band are increased gradually as the crystallization temperature rises, with a sharp reflection peak at 985 cm⁻¹, and the highest reflectance of 13.8%.

This study discusses the effect of As content addition on the glass density, molar volume, compactness and optical properties of $A{s}_{x}S{e}_{80-x}{S}_{20}(0.0\leqslant x\leqslant 55\,{\rm{at}} \% )$ glasses. The coordination number of Se and S atoms is the same, i.e. N_Se = N_S = 2, while, N_As = 3. Thus, the coordination number of the present glass increases with increasing the As content. Values of the glass density, compactness and width of localized states increase whereas, values of the molar volume (V_m), optical band gap (E_g) and Tauc parameter ($\sqrt{\beta }$) decrease with the addition of As content. In this study, there is a stoichiometries glass at 24 at% As content with Se-S and As-Se bonds. The obtained results are consistent with each other and are discussed in detail based on the chemical bonds of the glasses as well as the Mott and Davis model.

A study was performed to determine the effect of the content of fillers on the mechanical properties of a nylon 12 matrix composite mixed with graphene flake. The reinforcement fillers were dispersed in nylon 12 matrix before filling in the mode. Scanning Electron Microscope (SEM) were used to observe the morphology characterizations of reinforced composites and mechanical properties were determined by conducting tensile test, hardness. It is note that mechanical performance increased by 49.7% in tensile strength, 35.8% in Young's modulus and even 362.6% in hardness than that of neat nylon 12 with the addition 2.5 wt% of graphene.

In this study, a two-element model consisting of a non-linear spring and a viscous dashpot was proposed to simulate tensile curve of polyurethane fibers. The results showed that the two-element model can simulate the tensile curve of the polyurethane fibers better with a simple and applicable feature compared to the existing three-element model and four-element model. The effects of isocyanate index (R) on the hydrogen bond (H-bond) and the micro-phase separation of polyurethane fibers were investigated by Fourier transform infrared spectroscopy and x-ray pyrometer, respectively. The degree of H-bond and micro-phase separation increased first and then decreased as the R value increased, and gain a maximum at the value of 1.76, which is in good agreement with parameters viscosity coefficient η and the initial modulus c in the model.

Dielectric elastomers (DEs) are belonged to a group of polymers which cause a time-dependence deformation due to the effect of viscoelastic. In recent years, viscoelasticity has been accounted in the modeling in order to understand the complete electromechanical behavior of dielectric elastomer actuators (DEAs). In this paper, we investigate the actuation performance of a circular DEA under different equal, un-equal biaxial pre-stretches, based on a nonlinear rheological model. The theoretical results are validated by experiments, which verify the electromechanical constitutive equation of the DEs. The viscoelastic mechanical characteristic is analyzed by modeling simulation analysis and experimental to describe the influence of frequency, voltage, pre-stretch, and waveform on the actuation response of the actuator. Our study indicates that: The DEA with different equal or un-equal biaxial pre-stretches undergoes different actuation performance when subject to high voltage. Under an un-equal biaxial pre-stretch, the DEA deforms unequally and shows different deformation abilities in two directions. The relative creep strain behavior of the DEA due to the effect of viscoelasticity can be reduced by increasing pre-stretch ratio. Higher equal biaxial pre-stretch obtains larger deformation strain, improves actuation response time, and reduces the drifting of the equilibrium position in the dynamic response of the DEA when activated by step and period voltage, while increasing the frequency will inhibit the output stretch amplitude. The results in this paper can provide theoretical guidance and application reference for design and control of the viscoelastic DEAs.

The graphene oxide sheets (GO) were modified by silane coupling before incorporation into the aromatic polyimide (PI) matrix via in situ polymerization. The successful grafting of silane coupling onto the surface of the graphene was confirmed by FTIR, x-ray diffraction, and Raman spectroscopy. The incorporation of modified graphene oxide(K-GO) sheets significantly enhanced the thermal stability and tensile properties of PI. It was found that the tensile stress and the Young's modulus of 0.5 wt%K-GO/PI were increased by 27.2% and 28.0% from pure PI, respectively. The T_5% values of 0.5%K-GO/PI (507 °C) were obviously higher than that of pure PI (491 °C). Compared to pure PI, the PI composites with the K-GO addition of 0.5 wt% exhibits much lower friction coefficient (0.361) and wear rate (1.247 × 10⁻⁵ mm³ N⁻¹m⁻¹). This can be attributed to the enhanced effect of K-GO addition on the properties of the composites. This study aims to expand the range of applications of graphene and to solve wear-related mechanical failures for polymer parts.

In this study, the effect of high density polyethylene (HDPE) and calcium carbonate (CaCO₃) addition into constant amount of low density polyethylene/linear low density polyethylene (LDPE/LLDPE) matrix was investigated by using different mechanical and thermal parameters. Then, analysis of variance (ANOVA) was used to investigate the normal distribution of obtained data. Finally, sample containing 50 Phr of HDPE and 7 Phr of CaCO₃ microparticles, was determined as optimized sample. The effect of different process parameters such as injecting back pressure, cooling and retention time, on mechanical and thermal properties of optimized sample was investigated as well. Also to investigate the effect of the number of recycling processes on the mechanical and thermal properties, two dominant degradation mechanisms were suggested. The first was the decreasing of chains molecular weight and formation of short length chains and the later was the formation of crosslinks and three dimensional networks. Results indicated that by increasing the number of recycling processes, crystallinity, melting point, modulus, strength at yielding point and toughness in comparison to pristine sample decreased at first and then showed an ascending trend. Elongation at break by increasing of the number of recycling processes, generally increased in comparison with initial sample.

The objective of this study is to explore the effects of maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) on properties of polypropylene (PP)-based binder. The viscosity of feedstocks as well as properties of green parts, brown parts and sintered parts were investigated. Through the analysis of viscosity, the feedstock containing 8 vol% POE-g-MAH in binder was supposed to be more suitable for the injection molding. The impact absorbed energy at break increased with increasing POE-g-MAH content in binder while the bending strength decreased first and then increased. The introduction of POE-g-MAH improve the density distribution and increased the density of green parts. After debinding, most binder components were removed regardless of the POE-g-MAH content in binder. As for the parts after sintering, the carbon content decreased with an increase in POE-g-MAH content. The results suggest that POE-g-MAH act as a toughening agent as well as compatibilizer for PP-based binder/metal powder system. The mechanical properties of the green parts could be enhanced even after multiple injection and in addition the powder-binder separation trend could be decreased.

It is widely recognized that the extension limit of polymer chains has a significant effect on the snap-through instability of dielectric elastomers (DEs). The snap-through instability performance of DEs has been extensively studied by two limited-stretch models, i.e., the eight-chain model and Gent model. However, the real polymer networks usually have many entanglements due to the impenetrability of the network chains as well as a finite extensibility resulting from the full stretching of the polymer chains. The effects of entanglements on the snap-through instability of DEs cannot be captured by the previous two limited-stretch models. In this paper, the nonaffine model proposed by Davidson and Goulbourne is adopted to characterize the influence of entanglements and extension limit of the polymer chains. It is demonstrated that the nonaffine model is almost identical to the eight-chain model and is close to the Gent model if we ignore the effects of chain entanglements and adopt the affine assumption. The suitability of the nonaffine model to characterize the mechanical behavior of elastomers is validated by fitting the experimental results reported in the open literature. After that, the snap-through stability performance of an ideal DE membrane under equal-biaxial prestretches is studied with the nonaffine model. It is revealed that besides the prestretch and chain extension limit, the chain entanglements can markedly influence the snap-through instability and the path to failure of DEs. These results provide a more comprehensive understanding on the snap-through instability of a DE and may be helpful to guide the design of DE devices.

Hybrid composites based on polypropylene (PP), glass fiber (GF) and halloysite nanotubes (HNT) were prepared in the presence of a compatibilizer, polypropylene grafted with maleic anhydride (PP-g-MAH), in a twin screw extruder. The properties of the micro composite (PP/GF), nanocomposite (PP/HNT) and hybrid composite (PP/GF/HNT) were studied and compared. The dispersion of the fillers in the base matrix and the effectiveness of the compatibilizer were ascertained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR). The tensile strength and modulus of the hybrid composite prepared in the presence of PP-g-MAH were found to be superior to those of the compatibilized micro and nanocomposites. Differential scanning calorimetry gave insight to the effect of the fillers on modifying the crystallization behavior of the base polymer. The combination of GF and HNT increased the crystallization temperature of PP phase in all the composites. The dynamic mechanical analysis proved that the fillers introduced in the polymer matrix restricted the relaxation of the PP polymer chains as evidenced by the rise in the glass transition temperature (T_g). The thermal stabilities of the hybrid composites were far superior to the neat polymer as the fillers formed an insulating layer delaying the degradation tendency and elevated the activation energy. The flammability of PP could be modified tremendously by the incorporation of the fillers as they reduced the burning rate and raised the limiting oxygen index values.

AC-conductivity measurements using dielectric spectroscopy are performed at a temperature of 260 °C on parylene N films during the isothermal β₁–β₂ phase transition. The charge dynamic is used as the electrical marker to probe the phase transition. During this latter, a decrease of one order of magnitude is observed for the conductivity below the cut-off frequency f_c with constant values reached after 300 min. Below the cut-off frequency, the decrease of the normalized conductivity vs time is frequency independent, this behavior is similar to this observed in the case of the f_c values. Above the cut-off frequency, the conduction mechanism is affected by the phase transition, the Jonscher power exponent n_hf shows a variation comparable to this of f_c. These extracted parameters seem to be useful to probe this transition and to reach materials properties stability.

Thermally sensitive, ceria based proton conducting solid polymer electrolyte films were prepared by doping ammonium ceric sulfate complex salt in a PVA matrix using solution casting method. The prepared films were characterized using FTIR, FESEM, TGA, UTM and impedance analyzer in order to understand structural, morphological, thermal, mechanical and electrical properties CeO₂ nanoparticle based PVA/ACS composites. The presence of spindle shaped CeO₂ nanoparticle was confirmed from FESEM micrographs. The prepared films shown good thermal stability up to 200 °C. The 15 wt% ACS doped PVA electrolyte shown good conductivity, mechanical strength and thermal stability. The Rice and Roth model have been used to evaluate transport parameters and it reveals that enhancement in conductivity is due to increment in the number density of mobile ions as the increase in salt concentration.

The present work focuses on the electrospinning ability, the evaluation of resulting surface morphology and mechanical response of PMMA polymer blend nanofibrous membranes. For this purpose, electrospinning ability of PMMA polymer blend is firstly investigated by exploring various set of electrospinning parameters. From the evaluation of surface morphology of the resulting electrospun membranes, the optimum parameters are identified. Using these optimum parameters, tensile specimens are subsequently produced. Three deformation modes are considered: monotonic tensile test, cyclic test with increasing maximum strain and cyclic-relaxation test. Morphological analysis shows that the optimized tensile specimens are initially isotropic on the plane. The mechanical test results highlight the strong inelastic responses of the materials, which include inelastic strain and time-dependent behavior characterized by stress relaxation. Finally, in situ tensile test outcomes suggest that strain-induced fiber re-orientation took place.

The metal-insulator transition taking place in Polyaniline (PAN) is investigated in a one-dimensional configuration when impurities are introduced by doping. The electronic transport is numerically analyzed, representing the system by a Hückel tight-binding Hamiltonian and using the non-equilibrium Green's function formalism to obtain the conductance of the system under the presence of polaron and bipolaron doping. In a detailed analysis, we highlight the importance of studying extensive N sites chains, evaluating the conductance as a function of the de-coherence parameter η, decreasing it to the limit of 0⁺ ; this procedure allows us to study the existence of delocalized states in this system. It was possible to verify that although the bipolaron/polaron doping produces a displacement of the Fermi energy into a region of states outside the gap of the pure polymer, the conductance in the limit of zero inelastic scattering is zero, showing the existence of localized states at the Fermi level, due to disorder. This result indicates that the description of PAN as a linear one-dimensional object analyzed in a extensive N sites disordered chain does not manifest correlated disorder as proposed by the Random Dimer Model (RDM), where transport could occur because $\sqrt{N}$ of the electronic states are extended. The lack of charge diffusion at the Fermi level in this one-dimensional description of the system shows that it is not an adequate model to study the metal-insulator transition when the polymer is doped. The incorporation of the nature of the polymerization process, introducing higher dimensional effects in its early stages, is possibly an essential ingredient to derive an appropriate model to describe the conducting behavior of the PAN system.

The fabrication of highly transparent piezoelectric transducers is of increasing interest in the scientific and technological community. In this work, polymer based piezoelectric transducers were fabricated by the direct deposition of each layer forming the transducer on the desired substrate, avoiding the use of coupling layers. Transparent conductive oxide (TCO) electrodes were deposited by magnetron sputtering and piezoelectric films based on the copolymer poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) were deposited by spin-coating. All layers were processed and characterized to obtain a highly transparent piezoelectric P(VDF-TrFE) transducer with a strong adhesion between layers and preserving the piezoelectric response of the copolymer film. Indium tin oxide (ITO), gallium-doped zinc oxide (GZO) and aluminium-doped zinc oxide (AZO) were evaluated, and the best performance was obtained with AZO. The optimized transducer features an optical transmittance higher than 75% in the visible spectral range and a piezoelectric coefficient ∣d₃₃∣ of 34 pC.N⁻¹.

The perfluorinated ethylene-propylene (FEP) having unstable end groups (–COOH, –COF and –CF=CF₂) were stabilized via esterification with short-chain alcohols. The effect of different alcohols on the esterification of FEP was evaluated by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis with mass spectrometry (TGA-MS). The results of IR indicated that the end-capping using methanol at 140 °C (FEP-M140) got the much better effect in converting the labile end groups of FEP into –COOCH₃ group with high stability, which was further proven by TG-MS that more weight loss together with more evolved CO₂ gas for FEP compared with FEP-M140 were detected. It was very visual that more bubbles caused by the evolved gas distributed in FEP than FEP-M140 films during hot processing, further confirming the end-capped FEP displayed better thermal stability than the uncapped one.

Aseptic loosening induced by wear debris is a major problem for artificial joints. Besides, the nonfunction of secreting synovial fluid weakens the formation of the lubricating film on the surface of artificial joints after joint replacements. In this contribution, a thermosensitive poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC) hydrogel carried BSA (PCEC/BSA) was synthesized and was filled into textured dimples, which were used as the depots of PCEC/BSA composite hydrogel in the textured surface. The results indicated that PCEC/BSA hydrogel can release BSA lubricant slowly as an efficient carrier and form a thin protein adsorption film on the sliding region. The laser-textured surface with a pitch/diameter ratio of 1.2 has 39.1% ∼ 58.0% lower friction coefficient than that of un-textured surface under simulated body fluid, which is mostly because protein adsorption effect can be applied on this special design to achieve sustained-release lubrication action. This work offers a new insight on the design of textured dimples storing artificial lubrication matterials.

In this work, in order to improve the dispersion and reinforcement of waterborne polyurethane (WPU), nano-SiO₂ was modified with a amphiphilic polymeric surfactant poly(propylene glycol) phosphate (PPG Phosphate) and oleic acid for comparison, then incorporated into WPU through in situ polymerization. The results show that both of the PPG phosphate and oleic acid were successfully grafted onto nano-SiO₂ surface and significantly improved its hydrophobic property. Scanning electron microscopy (SEM) observation reveals that PPG phosphate modified SiO₂ nanoparticles had good compatibility with WPU and uniformly dispersed into WPU matrix. The results also show that the tensile strength, water resistance and thermal stability were all significantly improved by incorporation of nano-SiO₂, especially PPG phosphate modified SiO₂, which was attributed to its good dispersion in WPU and strong interface adhesion.

Membrane distillation is a promising method for water desalination and wastewater treatment. This method requires membrane with high hydrophobicity, efficiency and low cost. In this study, track-etched membranes based on poly(ethylene terephthalate) (PET TeMs) with hydrophobic surface were prepared by modification using dichlorodimethylsilane and 1H, 1H, 2H, 2H-perfluorododecyltrichlorosilane. Modification of the surface of PET TeMs with pore size of 221 nm and thickness of 12 μm led to increasing of contact angle up to 134°. Prepared membranes were investigated by x-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDX), goniometric analysis, liquid entry presser (LEP) analysis and gas permeability test. The performance of the membranes at different salinities was evaluated using direct contact membrane distillation (DCMD) process. The results show maximum permeate flux of 1189, 812, 510, and 125 g/m² · h (dT = 75 °C) during 24 h saline solution operation (1.5, 10, 15 and 30 g l⁻¹ respectively) with efficiency of 99.5%.

In this work, oxidized and fluorinated multiwall carbontubes (MWCNTs) were prepared and used with carbon black (CB) as hybrid fillers to reinforce fluoroelastomer (FKM). The effects of MWCNT functionalization and CB/MWCNT ratio on mechanical, thermal and tribological properties of the nanocomposites were investigated. FT-IR and TGA confirmed the attachment of functional groups on the sidewall of the treated MWCNTs. FE-SEM showed that the dispersion of fluorinated-MWCNTs in the matrix were more uniformly than the oxidized-MWCNTS. Rheometer test revealed that there is a remarkable increase in the cross-linking density of the nanocomposites associated with increase of the fluorinated-MWCNTs. Therefore, FKM/CB/fluorinated-MWCNT nanocomposites exhibited better mechanical, thermal and sliding wear properties than FKM/CB/oxidized-MWCNT ones. The mechanical and tribological properties were found to enhance with increasing functionalized-MWCNTs to a certain ratio, then began to decline gradually. The optimum mechanical and tribological properties of FKM/CB/fluorinated-MWCNT were at CB/fluorinated–MWCNT loading of 20/10 and 17.5/12.5, respectively. In contrast, the optimum properties of FKM/CB/oxidized-MWCNT were at CB/oxidized –MWCNT loading of 25/5. FE-SEM of worn surface disclosed that the main wear mechanism for the FKM/treated-MWCNTs nanocomposites was fatigue, compared to adhesive wear marks appeared in the nanocomposites with a high ratio of pristine-MWCNT. Mechanically and tribologically superior FKM/CB/Fluorinated-MWCNT nanocomposites are very attractive for sealing system in automotive, aerospace and oil field applications.

Soft material contact analysis plays an important role in the theory of non-linear contact mechanics on both macro and micro scales. Understanding the conforming nature of soft materials with various contact destinations is of considerable interest which involves design of mechanical components involving soft materials. This work presents a FEM based investigation on the contact parameters of a soft splined hemispherical finger-tip pressed against a rigid curved profile. The contact parameters viz., contact pressure, contact radius and vertical deformation for different loads are estimated by FEM based axis-symmetric model. The geometry of the splined portion on soft finger-tip is specified by the length, width and depth. The load-contact relationship for different splined profiles was completed and discussed. From the results, it is observed that the magnitude of vertical depression of splined fingertip is always greater than the normal rigid fingertip. The underlying physics behind this phenomenon is due to large lateral deformation in the splined profile. Then the magnitude of contact radius decreases with the increase in length of the spline. Also, the width of the spline plays an important role in the development of contact area. Moreover, additional grasping strength will be attained due to the vacuum generated in between the splines.

Progressive damage models based on continuum damage mechanics are used in combination with cohesive elements to explore the effect of three different failure criteria including Chang-Chang, Hashin and Puck criteria, on the structural response and the failure mechanisms of composite laminates subjected to low-velocity impact. Three different failure criteria and damage evolution laws based on equivalent strain are used for intralaminar damage models, and the delamination is simulated by the bilinear cohesive model based on quadratic criteria. A new numerical optimization method combining analytical approximation and Golden section Search has been applied in Puck criteria to search the fracture plane. Numerical analysis is performed on two composite laminates specimens with different materials, layups and impact energy to study the impact force-time, force-displacement and absorbed energy, computational cost, as well as the damage evolution behaviors of fiber, matrix and delamination. The numerical results with three different failure criteria show acceptable accord with available experimental data, which validate the accuracy of the proposed damage model. Moreover, this research can be helpful to select appropriate failure criteria in the progressive failure analysis of composite laminates under low velocity impact.

Ultraviolet (UV) cured adhesives have attracted wide attention and investigation in the fields of health care and electronic components due to their quick curing rate, low energy consumption and solvent pollution. At present, the adhesive systems bearing epoxy acrylate components have prevailed in the field of electronic industry packaging. These systems show some advantages such as low cost, high reliability, excellent mechanical traits and fine solvent resistance. However, the affecting factors of the noumenal esterification reaction to synthesize epoxy acrylate prepolymers have hardly been reported. In order to clarify the affecting factors, in this work, the key pre-polymer components in application of UV cured adhesives were designed and further prepared based on noumenal esterification between epoxy resin and acrylic acid. Three kinds of varied epoxy resins were employed to prepare desired epoxy acrylate pre-polymers. Impacts of reaction temperature, epoxy resin type, catalyst content, catalyst class and raw material feed ratio on noumenal esterification reaction were deeply studied. Some valuable conclusions were achieved. This work might open the door to the large-scale synthesis of promising epoxy acrylate pre-polymers to construct high-performance UV curing adhesives by regulating noumenal esterification.

The present paper evaluates the performance decline of Polyulfone and Polysulfone-Graphene oxide nanocomposite membranes by biofouling. The membranes were exposed to two different bacteria, - Klebsiella and Pseudomonas for 3 days at a constant temperature of 30 °C and 40 °C. Upto 96.66% decline in water-flux was observed when the polysulfone membrane was exposed to Pseudomonas strain at 30 °C; however the percent decline for nanocomposite membrane was significantly lower. The fouled membranes were treated with sodium hypochlorite to remove the biofouling and it was found that % increase in water-flux after the treatment was more pronounced in case of nanocomposite as compared to polysulfone membrane for Klebsiella strain. The absolute water-flux was higher in nanocomposite membrane as compared to polysulfone membrane for both cases. The fouling was quite evident in scanning electron micrographs and atomic force microscope analysis, which got removed significantly by the treatment.

Mechanical behavior of particle-loaded laminated composites depend upon the type of matrix, filler, reinforced fibers and architecture of fibers. Further, buckling behavior of a laminated composite varies with its end conditions, i.e. free-free or fixed-fixed. Failure mechanisms like delamination, debonding and fiber fracture vary with the end conditions of buckling. Presence of hard filler may also change the buckling behavior. Thus, in the present article, the mechanical and buckling behavior of cement loaded woven glass fiber reinforced epoxy matrix composites were investigated. Cement was varied as 1%, 3% and 5% by weight of epoxy. Thickness of composites were also varied as 3.1 mm, 4.4 mm and 6.3 mm by varying the number of reinforced glass fiber mats. Tensile, Izod impact and Vickers micro-hardness tests and, buckling tests under free-free and fixed-fixed conditions were performed to assess the mechanical and buckling behavior respectively. Fractured composites were analyzed under scanning electron microscope (SEM). The results showed that tensile strength decreased and hardness increased with increase in percentage of cement. Composites with minimum thickness showed lowest tensile strength. Critical buckling load increased with increase in thickness of composites for both end conditions. However, the nature of variation of buckling load with the percentage of filler varies for every thickness. SEM images showed that damage of composites mainly involved fiber breakage and delamination. Cement particles were effective in deflecting the advancing crack.

There are various parameters that affect the mechanical properties of tubular braids. The purpose of the current study is to investigate the effect of weaving pattern and core yarn type on the mechanical properties of reinforced and unreinforced braids. For this aim, three different patterns for the polyester sheath were considered namely; 1/1 (Diamond), 2/2 (Regular) and 3/3 (Hercules). In addition, polyester and polypropylene yarns with different counts were used as the core part. To investigate the effect of resin on the braid properties, the Vacuum Infusion Process (VIP) method was used by applying polyester resin. The mechanical properties of the products were investigated and analyzed statistically. After that, the properties of the braid and braided composites were modeled using regression methods and the obtained results indicated that the considered models are not appropriate predictors.

Ionomeric membranes are essential constituents of many ionic devices including fuel cells, lithium-ion polymer batteries, and ionomeric polymer transducers. Understanding the dynamics of ionic conductivity of ionomeric membranes is significant in better understanding and optimizing ionic devices. In this work, effects of temperature and Van der Waals volume of Nafion counterions on ionic conductivity of Nafion ionomeric membrane are studied. Ionic conductivity of lithium (Li⁺), potassium (K⁺), and 1-Ethyl-3-methylimidazolium (EMI⁺) ion-exchanged Nafion membranes at temperatures varying from 30 °C–70 °C was investigated and a direct correlation between ionic conductivity and both temperature and Van der Waals volume of counter ions was observed. Ionic conductivity as a function of temperature (for all three counterions) exhibited two distinct slopes below and above ∼50 °C which is an indication of changes in activation energy and confirms previously claims of ionic decomposition of EMI-Tf ionic liquid around ∼50 °C.

A facile procedure to modify glass film with zwitterionic polymers for improving the blood compatibility was introduced. The glass slides were first silanized with 3-methacryloxypropyltrimethoxysilane (MPT) to generate methacrylate groups on the surface. Then, N, N'-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl) ammonium (DMMSA), a sulfobetaine zwitterionic monomer, was polymerized on the silanized glass substrates by free-radical polymerization in order to graft the zwitterionic polymers onto the substrates. X-ray Photoelectron Spectroscopy (XPS), water contact angle, scanning electron microscope (SEM) and atomic force microscopy (AFM) were utilized to analyze the surface properties of the grafted glass. The blood compatibility of the grafted glass was verified by whole blood contacting and platelet adhesion experiments in vitro. The results showed that the zwitterionic polymers were successfully grafted on the glass surface, and consequently significantly inhibited the platelet adhesion and whole blood cell attachment.

In recent years, poly(etheretherketone) (PEEK) has been used as a replacement for the metal used in knee prostheses due to its good biocompatibility, abrasion resistance and corrosion resistance. A tangential fretting experiment on the contact interface of the tibial component (PEEK) and the highly cross-linked polyethylene (XLPE) gasket is carried out, and medical Ti6Al4V is used as a comparison to PEEK. The results show that (1) replacing the metal with PEEK does not cause increased fretting wear. Therefore, in view of the numerous advantages of PEEK, it is advocated as a prosthetic implant material. (2) The friction coefficient between the contact surfaces of PEEK and XLPE increases with an increase in the micromotion amplitude and decreases with an increase in the normal load. (3) The wear quality of fretting increases with an increase in the micromotion amplitude, normal load and number of cycles. (4) Wear occurs mainly on the edge of the contact surface, and the wear mechanism is adhesive wear and abrasive wear.

This investigation focuses on the in situ preparation of cobalt oxide through a less explored potentiodynamic approach under ambient conditions. A spinel structured feather like p-type cobalt oxide is obtained having dual bandgaps. Gracing Incidence x-ray Diffraction, Raman spectroscopy, UV-Visble spectroscopy, Scanning Electron Microscope and Hall measurement are used to study the structural, optical, morphological and electrical characteristics of the film. The prepared film showed an excellent cyclic stability upto 1600 number of cycles and good charge retention as obtained from cyclic voltammetry and galvanostatic charge-discharge measurements. A high specific capacitance of 396.67 F g⁻¹, specific energy 71.40 Wh kg⁻¹ and specific power 10.02 kW kg⁻¹ is obtained, implying supercapacitive nature of the material. Overall a sustainable energy storage material, prepared by template free potentiodynamic method for new generation devices has been explored in this work.

The paper presents the results of investigation of defect formation in AlN ceramics under Fe⁺⁷ ion irradiation with a fluence from 1 × 10¹¹ to 1 × 10¹⁴ ion cm⁻². The change in the main crystallographic characteristics, the decrease in the magnitude of Griffiths criterion, and the increase in the average voltage as a result of irradiation are caused by the appearance of additional defects in the structure and their further evolution leading to a change in the degree of crystallinity. For samples irradiated with Fe⁺⁷ ions to a dose of 1 × 10¹¹ ion cm⁻², the formation of pyramidal hillocks is observed on the surface, whose average height is 17–20 nm. An increase in the irradiation dose leads to an increase in chillocks size and their density. At the same time, at large irradiation doses, the formation of conglomerates of chyllocks and grooves on the samples surface is observed. The change in surface morphology, the formation of chyllocks on the ceramic surface, and the dependence of the change in crystallographic characteristics during irradiation make it possible to unambiguously associate the formation of radiation defects in the structure of the ceramic with energy losses in elastic and inelastic interactions of iron ions with lattice atoms.

Biosorption is one of the most efficient and feasible methods for eliminating noxious wastes from the aqueous systems. The use of non-hazardous, low-cost and biodegradable chitosan as a biosorbent is of significant importance in the above context. Present study was aimed to develop a β-cyclodextrin (β-CD) incorporated chitosan biosorbent in the form of beads. The prepared biosorbent beads were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), x-ray diffraction (XRD) analysis, and thermo gravimetric analysis (TGA). The values of point of zero charge (PZC) of chitosan and β-CD incorporated chitosan beads were determined in the presence of an electrolyte by means of different methods including mass titration, salt addition and zeta potential ones. The SEM images exhibited roughened and porous morphologies which could enhance the adsorption of metal ions. The values of PZC of chitosan and β-CD incorporated chitosan biosorbent beads were found to be 6.38 and 7.12, respectively.

In this work, three-Dimensional nitrogen-doped graphene/MnO₂ (NG/MnO₂) was prepared by plasma treatment, which provides a high specific surface area due to porous structure and exhibits enhanced supercapacitor performance. The advantage of NG/MnO₂ electrode was obvious compared with reduced graphene oxide/MnO₂ (RGO/MnO₂) which was prepared by traditional hydrothermal method, such as improved electrochemical property and better cycling stability. The specific capacitance of NG/MnO₂ at the scan rate of 5 mV s⁻¹ (393 F g⁻¹) is higher than that of RGO/MnO₂ (260 F g⁻¹). In addition, NG/MnO₂ showed higher durability with 90.2% capacitance retention than that of RGO/MnO₂ (82%) after 5000 cycles. Such cheap and high-performance supercapacitor electrodes are available by our feasible plasma treatment, which give promise in large-scale commercial energy storage devices.

The pristine Li_1.20[Mn_0.52Ni_0.20Co_0.08]O₂ and Ce³⁺-doped Li_1.20[Mn_0.50Ni_0.20Co_0.08Ce_0.02]O₂ cathode materials have been synthesized by using the typical sol-gel method. The XRD, SEM, ICP-OES and galvanostatic charge-discharge tests were carried out to study the influence of Ce³⁺ doping on the crystal structural, morphology and electrochemical properties of Li_1.20Mn_0.54Ni_0.13Co_0.13O₂. The XRD result revealed the Ce³⁺ doping modification could decrease the cation mixing degree. The galvanostatic charge-discharge tests results showed that the sample after Ce³⁺ doping demonstrated the smaller irreversible capacity loss, more stable cyclic performance and better rate capacity than those of the pristine one.

In the present work, we have investigated the effect of Ni doping on the microstructure and photocatalytic properties of BiFeO₃ samples. All the compositions of BiFe_1−xNi_xO₃ (0 ≤ x ≤ 0.07) have been synthesized via cost effective ethylene glycol based sol-gel method. The Rietveld refinement of the XRD data revealed rhombohedral crystal structure with R3c space group. The FTIR spectroscopy confirms the formation of BiFeO₃ compound. UV–visible DRS result affirmed that the band gap of the samples can be tuned towards visible range by the Ni substitution. The photoluminescence spectra indicate lower intensity with the Ni content, signify reduction in recombination rate of the electron-hole pairs. The photocatalytic response of the nanoparticles was examined for the degradation of methylene blue (MB) dye under visible light irradiation and the highest photocatalytic response was observed for 7% Ni doped sample. Therefore, the observed results suggest potential application of the synthesized nanoparticles for wastewater treatment purpose.

Electrochemical impedance spectroscopy (EIS) has been applied to characterize the structure of polyvinylidene fluoride (PVDF) membranes. The characteristic frequency, which directly obtained from the original EIS data, was used to clarify the difference of the membranes' structures. The experimental data indicated the equivalence between the characteristic frequency and the membrane resistance fitted from the equivalent circuit. The results evidenced that the characteristic frequency obtained directly from original EIS data without any fitting calculation can be used for in situ characterizing a membrane instead of the membrane resistance.

Piezoelectric textile fibres are important for wearable energy harvesting applications. Piezoelectric melt-spun fibres have been under investigation starting with 2010. While most of research has been carried out on fibres produced from polyvinylidene fluoride (PVDF) which is a widely researched piezoelectric polymer, attempts have been carried out at developing fibres from polypropylene (PP) which has mostly been researched when used in cellular form. Moreover, the piezoelectric behavior of the fibres has until now been characterized, only by the voltage produced by the fibres when they are tested under open circuit conditions. The research presented in this paper, investigated yarn specimens made of polypropylene mixtures with multiwalled carbon nanotubes (MWCNTs) regarding the electric power produced by the yarns. Measurement of the power was carried out using equipment developed by the research team and previously used to measure the power produced by monofilament piezoelectric textile yarns. The result of the current research indicate that the piezoelectric behavior of PP yarns is not affected essentially affected by the addition of MWCNTs and illustrate potential areas for further research of the behavior of piezoelectric PP yarns.

Hydrogen is considered a clean and sustainable alternative energy source in future, and transition metal phosphides as substitutes for Pt-based electrocatalysts for the hydrogen evolution reaction (HER) have received widespread attention. However, exploring a facile way to synthesize efficient catalysts is still a challenge. In this work, we found a simple and safe way to obtain tungsten phosphide (WP) and the influence of synthesis temperature was also investigated. Moreover, with the modification of Ketjen Black, WP/KB heterostructures were gained, which showed an excellent HER performance in both acidic and alkaline solutions with Tafel slopes of 60 mV dec⁻¹ and 66 mV dec⁻¹, respectively. Furthermore, a possible improvement mechanism was also discussed.

In the present work, we explore the modification of walnut shell using a solvent-free reaction, in which walnut is mixed with malonic acid cyclic isopropylidene ester, generating carboxylic acid-functionalized walnut shell. Using different analysis techniques, the presence of carboxylic acid groups on the adsorbent surface is confirmed. The efficiency of the modified adsorbent for the simultaneous removal of Pb²⁺ and methylene blue (MB) is studied. Optimization of the experimental parameters involved is carried out using the Box-Behnken design. Under the optimum experimental conditions, high removal percentages of 97.14% and 92.61% were acquired for Pb²⁺ and MB, respectively. Investigations made on the FT-IR spectra show that electrostatic forces play a major role in the adsorption of Pb²⁺, while π-π interactions and hydrogen bonding play more important roles in the adsorption of MB on the proposed adsorbent.

Mesoporous orthorhombic LiMnO₂ has been directly fabricated by a one-step flux method in this work. Benefiting from the unique mesoporous structure, the orthorhombic LiMnO₂ prepared through calcinating the mixture of flux LiOH · H₂O and Mn₂O₃ with various Li/Mn molar ratios shows enhanced lithium storage properties. When used as the cathode for lithium ion battery, the mesoporous orthorhombic LiMnO₂ has been found to exhibit a maximum discharge capacity of 191.5 mAh g⁻¹ and a high reversible capacity of 162.6 mAh g⁻¹ (84.9% retention) after 50 cycles at a current density of 0.1 C rate. These results demonstrate its potential application in high performance lithium-ion batteries.

The poor thermal stability of polyolefin separator greatly limits the output performance and safety performance of a lithium ion battery at high temperature. Herein, we report a novel silicone grafted polyolefin separator prepared by a simple solution process and its lithium ion battery performance. Despite its low coating thickness, the grafted silicone coating significantly improved the thermal stability of polyolefin separator. In addition, the silicone grafted separator shows enhanced electrolyte affinity. Due to these favorable features, the novel separator exhibits enhanced battery performance at a high temperature of 80 °C. Our results suggest that the silicone grafted separator could be potentially used in practical battery applications.

The paper reports a novel flexible electrode based on Fe₃O₄-embedded in carbon felt via a facile hydrothermal method. As a binder-free anode for Lithium ion batteries, it exhibits a stable reversible capacity of 590 mA h g⁻¹ after 100 cycles at a current density of 200 mA g⁻¹, together with modified rate capability. The improved lithium storage properties can be attributed to the synergistic effect between nano-sized embedded Fe₃O₄ and carbon felt substrate. The elastic carbon fibers are beneficial for alleviating the volume expansion of Fe₃O₄ during continuous discharge/charge cycling. Besides, the designed structure leads to shorter ion transport path and better diffusion of electrolyte, resulting in the enhanced rate capacity and reversible capacity. The structure, morphology and the electrochemical performances of Fe₃O₄/carbon felt electrode for flexible Lithium ion batteries are analyzed in details.

In this work, titanium nitride/multi-walled carbon nanotubes (TiN/MWCNTs) composites have been successfully prepared by a simple sol-gel method combined with ammonia annealing and then subjected to anode for lithium ion batteries (LIBs). TiN shells are homogeneously anchored on MWCNTs cores to form coaxial structure. Such TiN/MWCNTs composites with one-dimensional structure have rich nanopores, which can facilitate electrolyte access and provide rapid ion transportation. In addition, both TiN and MWCNTs have good conductivity, which is favorable to improve electron transfer. When employed as anode material for LIBs, the anodes based on TiN/MWCNTs delivered a high reversible capacity of 447 mA h g⁻¹ after 100 cycles at 300 mA g⁻¹, and outstanding cycling stabilities with a capacity of 385 mA h g⁻¹ after 500 cycles at 900 mA g⁻¹.

The antireflection coating deposition on the solar cell front faces can significantly reduce the optical losses. Unfortunately, these layers are not enough. For this, an application of an antireflection multilayer combining different materials is proposed as solution to reduce optical loss. In this study, an antireflection multilayer (single, 4 and 6 antireflection layers) have been modeled and realized. These multilayers based of silicon nitride and silicon oxynitride, were deposited by plasma enhanced chemical vapor deposition (PECVD, 13.56 MHz). The different results obtained over textured surfaces, exhibit that the best reflectivity value was 1.05% for the multilayer of 6 layers, compared to the 4 layers that was 3.26%.

This paper reports the enhanced catalytic activity of Ni-Re/H-AlMCM-41 catalyst for hydrodenitrogenation (HDN) of o-toluidine. The mesoporous H-AlMCM-41(Si/Al = 100) support was synthesized by hydrothermal method. The synthesized mesoporous H-AlMCM-41 (Si/Al = 100) was impregnated with xNi-5 wt%Re (x = 0, 1 & 3 wt%) by wetness impregnation method. The support and catalyst were characterized by XRD, N₂-sorption studies, DRS UV–Vis., HRTEM and TPD-NH₃. The catalytic activities of synthesized catalysts were tested for HDN reaction of o-toluidine. The oxide catalysts were pre sulfided at 673 K for 3 h using a ditertiary butyl polysulfide (DBPS) as sulfiding agent. The results of this study shown that 1 wt%Ni-5 wt%Re/H-AlMCM-41 catalyst exhibits higher HDN activity. The higher HDN activity associated with total number of sulfur species present in the sulfided catalyst. The results on characterization and catalytic activity have been correlated and discussed in detail.

We present the electronic structure, energetic stability, mechanical, and electronic properties of Mg₇XH₁₆ (X = Ti, Zn, Pd, Cd) ternary hydride systems using a first principles approach in the framework of density functional theory. The possible usage of these systems in hydrogen storage applications is discussed. The systems under investigation have lower formation enthalpy than conventional MgH₂ material indicating lower thermodynamic stability and improved hydrogen releasing capacity. All the systems are mechanically stable and compressible materials with relatively low elastic moduli values. In the electronic aspect, Mg₇XH₁₆ (X = Ti, Zn, Cd) systems are metal, but Mg₇PdH₁₆ is a zero-gap semiconductor with bands nearly touching at Fermi level (E_F) and zero density of state at E_F. This material can also have possible applications in optoelectronics.

The scope of this investigation is the photocatalytic degradation performance of newly synthesized nanoparticles (NPs); namely; Fe₃O₄; Fe₃O₄@TiO₂ and Fe₃O₄@SiO₂. Non-thermal synthesis methods are used to synthesize the NPs and to explore the ferromagnetic properties of the photocatalysts. The synthesized NPs are characterized using TEM, XRD, FTIR, TGA, VSM, and surface area analysis techniques. The photocatalytic activities of Fe₃O₄ and Fe₃O₄@SiO₂ NPs, put under solar irradiation, and Fe₃O₄@TiO₂ NPs, put under UV irradiation, are examined. The efficiency in degradation of Methylene Blue (MB) pollutant is shown to be the best for Fe₃O₄@SiO₂ NPs, then in Fe₃O₄ NPs, and lastly in Fe₃O₄@TiO₂ NPs. The silica (SiO₂) coating on Fe₃O₄ NPs significantly enhances the light absorption and is found to improve the MB degradation rate and the photoinduced charge generation and separation (i.e. it enhances the exciton lifetime). That makes the Fe₃O₄@SiO₂ NPs promising candidates for organic pollutants removal in various environment-related applications.

In this study, we load Cu₂O into gC₃N₄ via an ultrasonic reduction method. By doing so, the steady-state electron population is increased by 3 times. Due to the revealed critical role of Cu₂O in enhancing the electron population in gC₃N₄, the structural features of the loaded Cu₂O are studied with synchrotron x-ray absorption spectroscopy (XAS), including x-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS). Results show that the Cu species are present in +1 oxidation state in the form of nano-sized Cu₂O. Each Cu cation is approximately coordinated to 2 O anions with an average length of 1.85 Å. Loading 1 wt% of Cu₂O into gC₃N₄ generates H₂ with a rate of 7.53 μmol/g · h, which is more than 5-fold of bare gC₃N₄ (1.44 μmol/g · h), under visible light irradiation in the presence of methanol as holes scavenger. The examined Cu₂O/gC₃N₄ shows appreciable stability within 5 cycles of H₂ generation.

The impregnation and grafting are two common methods to prepare amine modified sorbents. In this paper, the coupling agent 3-[2-(2-Aminoethylamino)ethylamino]propyl-trimethoxysilane (denoted as 3N) and triethylenetetramine (TETA) were used as modifiers. A two-step method was used to modify KIT-6, namely, 3N was first grafted onto the surface of KIT-6, and then TETA was impregnated into the 3N grafted KIT-6. The CO₂ adsorption and desorption of the material were determined by thermogravimetric analysis. The samples were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and nitrogen physical adsorption-desorption. The results showed that the adsorption capacity of modified KIT-6 increased significantly. Sample of grafting mass ratio (3N:KIT-6) of 1 was selected to be further modified by TETA impregnation, the adsorption capacity of the adsorbent increased first and then decreased with the increase of TETA loading at 60 °C. At the TETA loading of 30 wt%, the maximum adsorption capacity is 2.063 mmol g⁻¹, which is 3.2 times higher than that of unmodified KIT-6. After five cyclic times of adsorption/desorption, the materials still have excellent adsorption capacities, indicating their well cyclic stabilities.

Superhydrophobic surfaces (SHSs) require a combination of a nano- or microscale rugosity and a low surface energy. However, SH is easily lost under relatively mild mechanical abrasion. Here, by introducing a mesh layer beneath the SH layer, we develop a method that significantly increases the mechanical durability of a SHS. Using the commercially available Ultra-ever Dry SH coating, we found that hardness, abrasion distance, flexibility and water-jet impact resistance all increase. These increases are attributed to the increased mechanical support offered by the presence of the mesh, which provides dynamic mechanical losses at the temperatures and equivalent frequencies of the applied stresses. The SH of the coating surface on both sliding abrasion and water jet impact, as determined by slide angle (SA), exhibits two steps; the first is associated with the wearing away of the surface nanoparticles, and the second, with the wear of the underlying microstructures. A comparison of the SAs, as a function of abrasion distance, demonstrates that the presence of the mesh can significantly protect the nanoparticles, improving and prolonging SH, thereby extending the number of applications of such coatings. The improved mechanical durability may be attributed to the mesh structure protecting the rugosity, and its ability to absorb the energy from both sliding abrasion and water-jet impact.

Ba(OH)₂ · 8H₂O /graphene nanoplatelets composite phase change materials were prepared in this paper. It can be found that Ba(OH)₂ · 8H₂O is able to be dispersed evenly on the surface of graphene nanoplatelets by scanning electron microscope. Further, relevant tests showed that the thermal conductivity of composite phase change materials can be improved by graphene nanoplatelets. The thermal conductivity growth rate of the composite phase change material with 1.5 wt% graphene nanoplatelets is the largest, which is 51.36%. The melting and solidification thermal cycling tests of composite phase change materials with graphene nanoplatelets showed that the supercooling degree and the heat storage time of Ba(OH)₂ · 8H₂O can be effectively reduced. According to the DSC tests, the melting point and the phase change enthalpy of Ba(OH)₂ · 8H₂O composite phase change materials are almost invariable after the graphene nanoplatelets is added. The excellent heat storage property is also maintained.

The CaO doped fused BaZrO₃ is a promising refractory for induction melting of titanium alloys. Therefore, the present study investigated the effect of CaO additive on the phase constitution and microstructure of the fused BaZrO₃ refractory by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Results revealed that the fused BaZrO₃ refractory contained a significant amount of ZrO₂ as a second phase. After doping CaO, the ZrO₂ phase was absent along with the formation of phase-1 (Ba_1−xCa_xZrO_3−σ) and phase-2 (Ba_1−yCa_yZrO_3−σ) due to the different replacement ratio of Ca for Ba-site. The fraction of phase-1 was increasing as well as the decreasing fraction of phase-2 with the increased content of CaO additive. Meanwhile, CaO functions as a role of sintering additive for improving the densification of fused BaZrO₃ refractory due to the generation of solid solutions. The result of interaction analysis indicated that CaO should be a suitable additive for improving the thermodynamic stability of fused BaZrO₃ refractory. It provides an effective framework for the further development of CaO doped fused BaZrO₃ refractory for induction melting of alloys rich in titanium.

In this work, calcium chloride hexahydrate (CaCl₂ · 6H₂O) was adopted as phase change material (PCM), and the supercooling degree of CaCl₂ · 6H₂O can be reduced to 0.3 °C by adding 5 wt% sodium metasilicate nonahydrate (Na₂SiO₃ · 9H₂O). Then the composite material of 'CaCl₂ · 6H₂O/5 wt% Na₂SiO₃ · 9H₂O' was added into the floor heating system as the phase change layer to analyze and compare its controlling effect for the indoor temperature under summer and winter conditions. The results showed that the cooling rate of the floor heating system with the phase change layer is lower about 78.7% than that of floor heating system without the phase change layer; the heating rate of the floor heating system with the phase change layer is lower about 70.1% than that of floor heating system without the phase change layer. This result showed that the 'CaCl₂ · 6H₂O/5 wt% Na₂SiO₃ · 9H₂O' composite PCM has a good application prospect in the field of building energy efficiency.

Sodium-ion hybrid capacitors (NHCs) are novel energy storage devices between traditional capacitors and batteries; the electrode materials of NHCs have attracted increasing attention. In this study, a NiMoO₄ and activated carbon (AC) have been used as the anode and cathode materials of NHCs, respectively. To the best of our knowledge, the NiMoO₄//AC NHC system has been reported for the first time. The NiMoO₄ was successfully synthesized by a one-step hydrothermal route. The NiMoO₄//AC system has a high energy density of 62.4 Wh kg⁻¹ and a high power density of 3500 W kg⁻¹. It also exhibits prominent cycling stability, with a capacity retention of about 70% after 6000 cycles. This excellent electrochemical performance can be attributed to the nanosheet structure of NiMoO₄, which can increase the contact area between the electrolyte and the active material, thus promoting the rapid insertion and extraction of Na ions. Therefore, the NiMoO₄ are promising anode materials for NHCs.

In paper, fly ash (FA for short, the solid waste from power plants) was chosen as the support and manganese acetate as the precursor of active components to prepare MnO_x/FA catalysts using impregnation method. The technological conditions were discussed and the results show that catalysts calcined at 400 °C with Mn content of 25 wt% exhibit over 80% NO conversion at 160 °C. Spinel Mn₃O₄ with mixed valency is the main phase in the catalysts, demonstrating the superiority in ion and electron transferring, redox properties and other abilities. Conclusion can be deduced that a promising prospect is just around the corner for catalysts with mixed valences. And the adsorption of reaction gases (NH₃, NO and O₂) indicates that Lewis acid sites exist mainly on MnO_x/FA catalysts, and O₂ prefers to enhance Brønsted acid sites. Finally, the cost reduction of catalyst preparation and the reuse of fly ash are achieved simultaneously.

Materials used in space vehicles components are subjected to thermally aggressive environments when exposed to atmospheric reentry. In order to protect the payload and the vehicle itself, ablative composites are employed as TPS (Thermal Protection System). The development of TPS materials generally go through phases of obtaining, atmospheric reentry tests and comparison with a mathematical model. The state of the art presents some reentry tests in a subsonic or supersonic arc-jet facility, and a complex type of mathematical model, which normally requires large computational cost. This work presents a reliable method for estimate the performance of ablative composites, combining empirical and experimental data. Tests of composite materials used in thermal protection systems through exposure to a plasma jet are performed, where the heat fluxes emulate those present in atmospheric reentry of space vehicles components. The carbon/phenolic material samples have been performed in the hypersonic plasma tunnel of Plasma and Process Laboratory, available in Aeronautics Institute of Technology (ITA), by a plasma torch with a 50 kW DC power source. The plasma tunnel parameters were optimized to reproduce the conditions close to the critical re-entry point of the space vehicles payloads developed by the Aeronautics and Space Institute (IAE). The specimens in study were developed and manufactured in Brazil. Mass loss and specific mass loss rates of the samples and the back surface temperatures, as a function of the exposure time to the thermal flow, were determined. A computational simulation based in a two-front ablation model was performed, in order to compare the tests and the simulation results. The results allowed to estimate the ablative behavior of the tested material and to validate the theoretical model used in the computational simulation for its use in geometries close to the thermal protection systems used in the Brazilian space and suborbital vehicles.

Rational construction of profitable microstructure in carbon-based electromagnetic composites is becoming a promising strategy to reinforce their microwave absorption performance. Herein, a N-doped highly porous carbon composite derived from thermal decomposition of Zn-based MOF (ZIF-8) has been synthesized for microwave absorption applications. The maximum reflection loss (RL) of −39.7 dB could be achieved with a thickness of 4 mm and the effective absorption bandwidth was from 7.9 GHz to 12.2 GHz covered X band (8–12 GHz). By comparing the porous carbon composites derived from conventional ZIF-8, it can be validated that porous structure, degree of graphitization and graphitic-N level is the key factors to improve the microwave absorption performance by increasing dielectric loss ability. The results demonstrated that the ZIF-8 derived graphitized nitrogen-doped porous carbon composites had great potential for microwave absorption performance, which may open up a new avenue to promote the electromagnetic applications of MOF-derived carbon composites.

Waste catalyst-derived adsorbent (WCDA) was prepared from the Mercury-containing waste catalyst (MCWC) that was obtained from PVC production process by the method of the microwave–assisted CO₂ activation, to remove methylene blue (MB) and methyl orange (MO) from the aqueous solution, achieving the utilization of waste hazardous resources. The optimal experiment condition of the preparation process was performed at 900 °C for 80 min with the CO₂ flow rate of 500 ml min⁻¹, with the good performance. The phy-chemical properties of WCDA and MCWC were investigated by N₂ adsorption, SEM, FTIR, Raman spectroscopy measurements and x-rayphotoelectronspectra. The WCDA is tested with MB and MO adsorption to assess its potential to liquid phase adsorption. The equilibrium adsorption data showed that the adsorption behavior followed the Langmuir isotherm. The result indicates that the WCDA can adsorb MO easier than MB. The kinetics experiments show that pseudo-second order model matches well the kinetic data. And the adsorption rate of the MO is larger than that of the MB. The above-mentioned analyses indicate that the preparation method of the WCDA is feasible and the WCDA can be as the promising adsorbent for MB and MO removal from aqueous solution.

Copper matrix carbon nanotubes composite films were fabricated by an electro-deposition process using copper plating solution containing homogeneously dispersed Multi-wall carbon nanotubes (MWCNTs) with by ultrasound assisted. The technological parameters, such as MWCNTs concentration in the solution, pH, pulse current density and ultrasound assisted were studied. When the concentration of MWCNTs was 2 g L⁻¹, the films were fine-grained and distributed uniformly. The highest content of MWCNTs in films was at the pH between 2 and 5, The MWCNTs network formed on the Cu coating at the pulse current density equal to 20 A dm⁻². The resistivity of composite films gradually decreased with increase in MWCNTs content. The structure of MWCNTs did not change during the electro-deposition. Electrical properties of both MWCNTs/Cu films and pure Cu were investigated after annealing at different temperatures. Results show that the resistance of the MWCNTs/Cu composite films reached minimum value after annealing at 400 °C.

The stability, electronic and the magnetic features of the transition metal atoms encapsulated C₂₀ cage cluster are investigated by GGA-PBE basis set. The results indicate that Ti and V atoms are more suitable for C₂₀ cage clusters than other transition metal atoms. The structural stability of the Ti@C₂₀, Fe@C₂₀ and Zn@C₂₀ clusters are better than that of other 3d TM@C₂₀ clusters. The reactivity of Co@C₂₀ cluster is higher than those of the other 3d TM@C₂₀ clusters. The spin polarization of the Mn@C₂₀, Mo@C₂₀ and Re@C₂₀ clusters are higher than that of their neighbors. And the Mn@C₂₀ core@shell cluster has the highest spin polarization. The VIII subgroup atoms have the smallest difference in the electronic transform from transition metal atoms to C atoms of the TM@C₂₀ clusters.

Vertical few layered graphene (VG) nanoflakes were directly synthesized on traditional glass substrate by the plasma-assisted chemical vapor deposition, where the extremely low growing temperature (<560 °C) and short time (<30 min) were involved. The VG microstructure could be well-controlled by tuning the plasma power, growth time and growth temperature. Raman, TEM, and SEM were used to determine the quality and single size of the VG. Because of the unique three-dimensional structure with high surface area, the VG network can provide superior thermal management capabilities, which has been demonstrated by the scalable frost removal. We believed that this hybrid system consisting of vertical graphene nanowalls and glass substrates has great potentials for future transparent 'green-warmth' constructions.

We study uniaxially strained graphene under the influence of non-uniform magnetic fields perpendicular to the material sample with a coordinate independent strain tensor. For that purpose, we solve the Dirac equation with anisotropic Fermi velocity and explore the conditions upon which such an equation possesses a supersymmetric structure in the quantum mechanical sense through examples. Working in a Laudau-like gauge, wave functions and energy eigenvalues are found analytically in terms of the magnetic field intensity, the anisotropy scales and other relevant parameters that shape the magnetic field profiles.

The electrochemical exfoliation of graphite in an aqueous ammonium sulfate solution, in combination with ultrasound treatment, has been studied. It allows obtaining a high yield of mildly oxidized graphene oxide flakes during 15 min. The oxygen atomic content in mildly oxidized graphene oxide can be set by the ammonium sulfate concentration in the range from 20 to 28% (C/O ratio ∼3–5). The minimum of oxidation degree has been found to correspond to the electrolyte concentration of 0.15 M. The obtained mildly oxidized graphene oxide can be used to produce a water-based suspension of good time stability (without any visible temporal changes for one month). The films prepared from the mildly oxidized graphene oxide suspension by the drop casting method have sheet resistance 10²–10³ kΩ/sq, depending on film thickness. The thermal reduction at a relatively low temperature of 300 °C allows obtaining conductive films with a sheet resistance of about 1.5 kΩ/sq for a thickness of about 100 nm. The thin films (∼16–20 nm) obtained by inkjet printing or the use of spin-processor have their sheet resistance of 10–60 kΩ/sq and carrier mobility of 5–7 cm² V⁻¹ s. The mildly oxidized graphene oxide suspension is promising for preparing stable water-based inks to be used in conductive printed layers and flexible electronics.

Three-dimensional (3D) porous conductive sponge with excellent electrical and mechanical properties has drawn great attention for developing wearable electronic skin (e-skin). Here, we reported a simple, practical and efficient 'dip-coating' technique to fabricate a resistive pressure sensor with excellent elasticity, high pressure sensitivity of 0.35 kPa⁻¹, long-term reproducibility and durability (∼2000 cycles), fast response time (∼45 ms), based on homogenous 3D hybrid conductive network of carbon black (CB)/multi-walled carbon nanotube (MWCNTs)/silicon rubber (SR) nanocomposites layer-by-layer dip-coated on porous polyurethane (PU) sponge. The good electrical and mechanical performances are achieved using the three-dimensional porous microstructure of polyurethane sponge and the synergistic conductive network of CB/MWCNTs. The fabricated sensor can be used to detect a small-scale human motion, including swallowing, coughing, breathing, clenching, screwing and exercising. The CB/MWCNTs/SR/PU based resistive pressure sensor with high performance and a simple fabrication process will provide new insight into the application flexible wearable electronic skin for real-time health monitoring, human activity monitoring and human-machine interfaces.

Currently problems of large toxicity, poor biocompatibility and high cost between polymer and crosslinking agent are found in traditional ionic gel electric actuator. To conquer such challenges, in this work, sodium alginate(SA) and calcium chloride(CaCl₂) were used to produce the biological gel electric actuator (BGEA). Furthermore, to achieve better response performance of the BGEA, two kinds of BGEAs with different concentrations of CaCl₂ and different concentrations of glycerol were prepared experimentally, and then the response performance of the BGEA was studied. The effect of calcium chloride on the BGEA showed that the concentration of calcium chloride had a great influence on the response performance of the BGEA, and the best concentration of calcium chloride was 0.95 g L⁻¹. Compared with the BGEA without crosslinking, the response speed and deflection displacement were increased by 1.64 times and 1.52 times respectively. The effect of glycerol on BGEA showed that although the response speed of the BGEA without glycerol was faster, the BGEA itself was dry, easy to break and weak to the external shock. Therefore, adding 1 ml of glycerol into the electrolyte membrane of the BGEA, not only increases the deflection displacement of the BGEA, but also avoids large reduction in its response speed.

We have developed novel multifunctional flame retardant polymer composites that exhibit better fire performance. Flame retardant polymer composites are prepared by infusing woven carbon fibers with phosphoric-acid-modified crosslinked diglycidylether of bisphenol-A epoxy matrix through the resin infusion under flexible tooling (RIFT) process. In this paper, we have explored various design factors of the fire retarding epoxy resin by modifying the resin physically as well as chemically. Different flame retardant epoxy samples are evaluated by compression test, UL 94, thermogravimetric analysis and dynamic mechanical thermal analysis. The fabricated flame retardant polymer composites have been characterized using in-plane shear test, to estimate the structural properties, and UL-94 test, to estimate the fire performance. In this study, a flame retardant composite, simultaneously exhibiting a UL-94 rating of V-0 and a shear modulus of 9.5 GPa, has been reported.

In this work, a simple approach to 3D printing of carbon black based shape memory polymer nanocomposites (SMP/CB) with toughness improving capabilities during programing stage using electrical stimulus is reported. Conductive SMP/CB nanocomposites, consisting of commercial SMP filled with conductive CB nanoparticles, were fabricated using solvent casting and single screw extrusion processes. Subsequently, material extrusion (ME) technique was used to 3D print dog bones type IV specimens for tensile test and electrical stimulus. It was found that SMP/CB electrical conductivity can be tuned by the filler fraction. In addition, electrical current passing through SMP/CB nanocomposites causes temperature increments and changes on material strength condition. Temperature profiles at various electrical current levels are reported. Moreover, Young's modulus and toughness of the 3D printed specimens subjected and not subjected to electrical current are presented. It was observed that conductive SMP/CB specimens responded to electrical current stimulus by increasing their toughness four times higher than with no current applied during tensile test. This paper is a reference for rheological and conductive properties of SMP/CB nanocomposites fabricated by ME 3D printing process.

A broadband near-perfect absorber in the visible region has been designed in this paper. This absorber consists of an alternating stack of metallic gratings and dielectric layers on the basis of a metallic substrate. Absorptivity and electromagnetic field distributions of the structure via the finite difference time domain (FDTD) method have been stimulated. The results show that the average absorptance of the absorber exceeds 95.2% in the wavelength range from 350 nm to 650 nm. The enhanced absorption can be ascribed to several mechanisms including surface plasmon polaritons, magnetic polaritons, and Fabry–Perot resonances. Besides, geometric effects on the resonance wavelengths have been investigated. Moreover, the effects of oblique incidence and polarization states on the spectral absorption have been analyzed. This designed absorber will be worth applying in solar energy harvesting via combining the study results mentioned above.

A nearly perfect dual-band deep sub-wavelength scale and temperature-controlled terahertz absorber is theoretically investigated. The absorber is composed of a periodic metal-dielectric stack array placed on a metallic substrate. Simulation results show that there are two distinct absorption peaks located at frequencies of about 0.140 THz and 0.192 THz in the spectra line under room temperature T = 300 K, and their maximum absorption rates are respectively 99.133% and 98.251%. It is also found that the period of the unit cell is less than 8.97% of the minimum resonant wavelength, which means the deep sub-wavelength absorber structure. Furthermore, it is shown that the proposed absorber is polarization-insensitive, and has good tolerance to the incident angle for both TE and TM wave, i.e., it is pantoscopic for the incident light. Meanwhile, when the temperature changes from 200 K to 400 K, the absorption of the two peaks did not change significantly within the considered frequency range, but the resonant frequency of the two absorption peaks will have a clear blueshift. The effect of structural parameters on the absorbing performance have also been discussed. This work provides a new idea for the design of frequency-agile deep sub-wavelength scale perfect THz absorbers, and the design scheme may be easily extended to the near ultraviolet, optical, infrared, terahertz and millimeter-wave regions.

Effect of Mg on microstructure and properties of 7000 high strength rolled aluminum alloy was studied by XRD and EBSD analysis, hardness and electric conductivity test, tensile test and intergranular corrosion experiments. The results show that for Al-8.95Zn-(1.9 ∼ 2.6)Mg-1.18Cu-0.44Zr 7000 series aluminum alloy, it has excellent comprehensive performance in T76 state with high tensile strength of 585 ∼ 645 MPa and elongation of 10.2 ∼ 15.4%, and the resistance to intergranular corrosion is excellent(≤72 μm). When the content of Mg is 2.21%, the aluminum alloy has the highest degree of recrystallization, and the strength and elongation rates of aluminum alloy with T6 and T76 aging state can reach 651.7 MPa and 10.7%, 645.6 MPa and 15.4%, respectively, but the resistance to intergranular corrosion is relatively poor. At the same time, the resistance to intergranular corrosion of the alloy decreases as the degree of recrystallization increases.

Bi₂O₂CO₃ microstructures self-assembled by nanosheets with exposed {001} facets were synthesized via a facile cetyltrimethyl ammonium bromide (CTAB)-assisted hydrothermal process. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and Photoluminescence (PL) spectra were used to characterize the as-prepared samples. Compared to Bi₂O₂CO₃ microstructure obtained without any template, the template-assisted Bi₂O₂CO₃ microstructure demonstrated enhanced photocatalytic activity, which mainly resulted from exposure of {001} facets, narrower band gap and less recombination of charge carriers. When the addition amount of CTAB was 0.6 g, the exposure percentage of {001} facets was largest, the band gap smallest and charge carrier separation most effective, giving rise to highest photoreactivity for RhB degradation. Approximately 97.67% of RhB degradation efficiency was achieved within 45 min. Moreover, holes were proved to be the dominant active species in the photocatalytic process.

In this paper, a new optically controlled tunneling field effect transistor (OC-TFET) based on SiGe/Si/Ge hetero-channel is proposed to improve optical commutation speed and reduce power consumption. An exhaustive study of the device switching behavior associated with different hetero-channel structures has been carried out using an accurate numerical simulation. Moreover, a new figure of Merit (FoM) parameter called optical swing factor that describes the phototransistor optical commutation speed is proposed. We demonstrate that the band-to-band tunneling effect can be beneficial for improving the device optical commutation speed. The impact of the Ge mole fraction of the SiGe source region on the device FoMs is investigated. It is found that the optimized design with 40% of Ge content offers the opportunity to overcome the trade-off between ultrafast and very sensitive photoreceiver performance, where it yields 48 mV/dec of optical swing factor and 155 dB of I_ON/I_OFF ratio. An overall performance comparison between the proposed OC-TFET device and the conventional designs is performed, where the proposed structure ensures high optical detectivity for very low optical powers (sub-1pW) as compared to that of the conventional counterparts. Therefore, the proposed OC-TFET provides the possibility for bridging the gap between improved optical commutation speed and reduced power consumption, which makes it a potential alternative for high-performance inter-chip data communication applications.

Array of TiO₂ dendritic structure with nanotubes was constructed on transparent conductive fluorine-doped tin oxide glass (FTO) with titanium potassium oxalate as titanium source. Sb₂S₃ nanocrystals were successfully deposited on the TiO₂ substrate via spin-coating method. Furthermore, TiO₂/Sb₂S₃/P3HT/PEDOT:PSS composite film was prepared by successively spin-coating P3HT and PEDOT:PSS on TiO₂/Sb₂S₃. It was demonstrated that the modification of TiO₂ dendritic structure with Sb₂S₃ could enhance the light absorption in the visible region. The champion hybrid solar cell assembled by TiO₂/Sb₂S₃/P3HT/PEDOT:PSS composite film achieved a power conversion efficiency (PCE) of 1.56%.

The non-linearity (NL) of monocrystal and polycrystal ZnO materials was studied on the basis of density functional theory. Firstly, wurtzite ZnO was selected as a candidate material for selector devices. As indicated by the calculated I-V curves on different ZnO surfaces, non-linearity and electrical conductivity varied among the ($12\bar{3}0$), (0001) and ($10\bar{1}0$) directions. The calculating models for wurtzite ZnO in three directions were named SF1, SF2 and SF3, respectively. SF1 and SF2 showed poor non-linearity although they demonstrated high electrical conductivity. SF3 exhibited excellent NL, but its electrical conductivity was low. Polycrystal ZnO material was studied, and three grain boundary (GB) models, namely, ZnO∑7($12\bar{3}0$)[0001]GB (GB1), 45° rotating GB(GB2) and ∑1($10\bar{1}0$)[$10\bar{1}0$]GB (GB3), were constructed. The GB barrier was found between two ZnO grains by calculating the I-V curves of GB and analysing the electrostatic potential, which resulted in NL improvement of GB compared with SF. By comparing the electrostatic potential analysis, we found that the electrical conductivity of GB3 was significantly enhanced to greater extent than that of SF3 because the Fermi level moved towards the conduction band. Therefore, the corresponding structure of polycrystalline ZnO should have better performance compared with single crystal ZnO to meet the selector design requirements. This work may be instructive and valuable for the design and optimization of ZnO-based gate selectors.

Dark brown ceria, CeO₂, with excellent photocatalytic properties, was synthesized by constructing a crystalline-core/disordered-shell heterostructure using NaBH₄ reduction. The structure, crystallinity and morphology of the as-prepared samples were characterized using x-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. The x-ray photoelectron spectra confirm a high concentration of Ce³⁺ and oxygen vacancies in the CeO₂ sample. The dark brown compound shows excellent properties especially with respect to solar-energy absorption but also the transfer and separation of charge carriers—due to its heterostructure-related features. The photocatalytic activity of the treated samples is obviously higher than that of pure CeO₂ and reaches the maximum with Ce³⁺/Ce molar ratio of 51.7%.

The fabrication of indium sulfide/graphene oxide composites (In₂S₃@GO) via a novel hydrothermal method was reported. The morphology of the composites showed that the daisy-like In₂S₃ structures were dispersed evenly on GO with large specific surface area. The photocatalytic performance of In₂S₃@GO was evaluated through photodegradation Rhodamine B. In₂S₃@GO exhibits higher photodegradation performance than that of pure In₂S₃. In addition, the composites showed great adsorption-desorption ability and stability. The solution pH value also has a significant influence on photocatalytic activity of In₂S₃@GO. This work may provide new insights to construct carbon-based semiconductor photocatalyst for organic dye pollution degradation.

Using a wider band-gap transparent conducting oxide (TCO) instead of CdS as the window layer of CdTe solar cells can increase the transmission of sunlight in the ultra-violet portion of the solar spectrum. In this paper, we tried to use Zn_1-xMg_xO (ZMO) which is a ternary alloy with a controllable wide band gap as an alternative to CdS layer. The band structures of ZMO with different Mg compositions were calculated by using first-principles. Based on the theoretical calculation results, ZMO/CdTe solar cells were modeled and the device performances were simulated by using SCAPS software. The results show that the high conversion efficiency was obtained when the ZMO conduction band minimum exceeded that of CdTe layer by more than about 0.13 eV (x = 0.125). Furthermore, we focused on the effect of the thickness, donor density and interface states density of ZMO film (x = 0.125) on the performances of CdTe solar cells, and compared it with the simulation results of CdS/CdTe solar cell. For ZMO/CdTe solar cell, the primary contribution of the efficiency improvement was from the enhancement of the short-circuit current density, which resulted from the increase of the EQE at the wavelength less than 510 nm. The carrier recombination was increased for the high donor density and interface state density of ZMO film, which resulted in the low EQE at the short wavelength. Therefore, the efficiency of CdTe solar cell could be further improved up to 18.69% for the ZMO film with the appropriate donor density and the low interface state density of 10¹⁴ cm⁻² eV⁻¹.

We synthesize the ZnO- SnO₂ hybrid with different amount of SnO₂ nanoparticles and study the photocatalytic performance of them for photocatalytic oxidation of methyl orange (MO) according to the statistical analysis for the first time. The ZnO-SnO₂ hybrids have been characterized by XRD, FTIR, TEM and UV–vis spectroscopy. XRD results reveal that the crystalline structure of SnO₂ with tetragonal structure and ZnO with hexagonal wurtzite structure is formed in the all synthesized hybrids. FTIR analysis emphasizes the existence of ZnO and SnO₂ nanoparticles in the all synthesized samples. TEM results show that the ZnO nanoparticles are modified using SnO₂ nanoparticles. The results of UV–vis spectrophotometer reveal that the photocatalytic degradation of MO increases with increasing amount of SnO₂ nanoparticles in the hybrid. Meanwhile, weight fraction and irradiation of UV dependence study also depict that the photocatalytic degradation of MO enhance with time and weight fraction of hybrid. The statistical analysis results reveal that the basic parameters and their interaction have a reasonable influence on the photocatalytic activity of the both hybrids.

Hierarchically porous CoTiO₃ powders with interconnected framework composed of nanoparticles as high performance gas sensing materials for ethanol were prepared by sol-gel method with C₄H₁₁NO₂ (DEA) as the chelating agent. A characteristic of hierarchical pore size distribution with both mesopores ranging from about 2 to 10 nm and macropores approximately from 0.15 to 3 μm can be found within the porous CoTiO₃ powders prepared at a molar ratio of DEA to Ti and Co of 1.6 : 1 : 1. The formation of macropores is mainly depending on the pore characteristics of gel skeletons before calcination, while the mesopores within macropore walls are generated after calcination. The sensing performances of porous cobalt titanate with different pore structure characteristics were compared based on the fabricated gas sensors. The hierarchically porous CoTiO₃ powders with a specific surface area of 47.04 m² g⁻¹ demonstrate the maximum response (71.5) towards 100 ppm ethanol at 420 °C. The corresponding response and recovery time are about 15 and 22 s, respectively.

Neutron diffraction, magnetic and magnetotransport studies of perovskites ${{\rm{R}}}_{1-{\rm{x}}}^{3+}$${{\rm{Sr}}}_{{\rm{x}}}^{2+}$(${{\rm{Mn}}}_{1-x/2}^{3+}$${{\rm{Sb}}}_{x/2}^{5+}$)O₃ (R = La, Pr) were carried out. It is shown that for x ∼ 0.2 systems undergo a transition from an antiferromagnetic state (x = 0) to a ferromagnetic state. In the case of the R = La series a structural transformation from the O'-orthorhombic phase (x = 0) to the O-orthorhombic one occurs, which is due to orbital disordering. At x ≥ 0.6 cluster spin glass like phases arise due to the competition between antiferromagnetic and ferromagnetic interactions, as well as due to the strong diamagnetic dilution. In case of the R = Pr series the structural transition into the O-orthorhombic phase was not observed under (Sr, Sb) codoping. As the ionic radius of the rare-earth ion decreases in the series R_0.7Sr_0.3Mn_0.85Sb_0.15O₃ the crystal structure distortion increases and the ferromagnetic state (R = La, Pr, Nd) is gradually transformed into a spin glass like state (R = Sm, Eu). The ferromagnetic compounds are insulators and exhibit a large magnitude of the magnetoresistance apparently associated with very small amount of Mn⁴⁺ ions. The covalent component of the chemical bond and e.g.-orbitals disordering/mixing are assumed to be responsible for ferromagnetism in the compounds under study.

Thermoelectric properties and specific heat of polycrystalline Pb₂FeMoO₆ have been systematically studied. The thermal conductivity increases monotonically with increasing of temperature, and reaches the maximum value 1.50 W m⁻¹ K⁻¹ at 350 K. The relatively low thermal conductivity is mainly attributed to the strong scattering effect of phonons at Fe/Mo sites. The negative Seebeck coefficient indicates the n-type conduction of the sample. The absolute value of S increases up to 20 μV K⁻¹ at 350 K. Due to the inhomogeneity resulting from Fe/Mo ions disorder, no distinct λ-type specific heat peak or anomaly typical for second-order transitions are observed.

We synthesized pure and Co-doped (6.25%–12.5% at.) ZrO₂ nanopowders in order to study their magnetic properties. We analyzed magnetic behavior as a function of the amount of Co and the oxygenation, which was controlled by low pressure thermal treatments. As prepared pure and Co-doped samples are diamagnetic and paramagnetic respectively. Ferromagnetism can be induced by performing low pressure thermal treatments, which becomes stronger as the dwell time of the thermal treatment is increased. This behavior can be reversed, recovering the initial diamagnetic or paramagnetic behavior, by performing reoxidizing thermal treatments. Also, a cumulative increase can be observed in the saturation of the magnetization with the number of low pressure thermal treatments performed. We believe that this phenomenon indicates that cobalt segregation induced by the thermal treatments is the responsible for the magnetic properties of the ZrO₂-Co system.

Effect of annealing on magnetic property-structure/microstructure correlation in nanostructured ribbons of a rare-earth-free Hf_1.5Zr_0.5Co₁₀FeB alloy has been reported in the present study. Melt-spinning of the arc melted alloy was employed to obtain the ribbons. The compositional, structural and magnetic measurements demonstrate that under optimized annealing conditions, the magnetically hard phases Hf₂Co₁₁B and ZrCo_5.1 appear as the dominant ones, while the magnetically soft phases Zr₆Co₂₃ and cubic Co appear as minor phase. The optimally annealed ribbons show promising values for characteristic magnetic parameters such as the saturation magnetization M_s ∼ 76.7 emu g⁻¹, intrinsic coercivity _iH_c ∼ 2.4 kOe and magnetic energy product (BH)_max ∼ 4 MGOe. Processing steps like magnetic alignment and magnetization would further improve the characteristic parameters.

In this paper, C-axis textured M-type barium ferrite BaSc_xFe_12−xO₁₉ (x = 0.2, 0.5, 0.7, 0.9, 1.1) have been synthesized via the solid-state method. Results of the SEM reveal that the Sc³⁺ has no obvious effect on the crystal morphology. However, Sc³⁺ ion have remarkable effect on tailor the magnetic properties of BaM ferrite. The measured results for the vibrating sample magnetometer indicate that increasing x of the induced Sc³⁺ yields decreasing the magneto-crystalline anisotropy field, saturation magnetization, coercivity, and reduces the squareness ratio. The site preference mechanism of Sc³⁺ on Fe³⁺ site in BaM hexaferrite crystal structure is also discussed.

Mg_0.2Mn_0.8Ho_xFe_2−xO₄ (x = 0.025, 0.050, 0.075 and 0.100) nanocrystalline is synthesized via a hydrothermal technique. Single phase cubic spinel is confirmed by XRD and the formation of Mg_0.2Mn_0.8Ho_xFe_2−xO₄ is verified by EDS. The average size for the nanoferrites is around 80 nm which is examined by TEM with the presence of agglomerated particles. Ho³⁺ substituted Mg-Mn nanoferrites exhibit the low saturation magnetization (M_s) and coercivity (H_c). Especially, with x = 0.100, the nanoferrites show the lowest M_s and H_c of 46.850 emu g⁻¹ and 46 Oe, respectively. The ferrite composites present the dielectric dissipation less than 0.37 and the magnetic loss less than 0.46 at 2–18 GHz. The low saturation magnetization, low coercivity and low dielectric dissipation indicate that the addition of Ho³⁺ contributes to synthesize better soft magnetic materials.

Asymmetric giant magnetoimpedance (AGMI) was created using two micro magnets placed at 1 cm away from the ends of amorphous ferromagnetic non-magnetostrictive (Fe_0.06Co_0.94)_72.5Si_12.5B₁₅ wire. At low frequencies, single-peak behaviour of the AGMI was observed, and the AGMI curves exhibited two-peak behaviour within high-frequency range. The asymmetry in the magnetization curves of amorphous wire with two micro magnets having the same orientation was found, the maximum of the GMI ratio at positive field region decreases from 515% to 356%, and the peak value at negative field region decreases from 513% to 261% at 1 MHz driving current frequency. A linear change in the AGMI curves was obtained, which could be of importance for magnetic sensor applications. Experimental results were qualitatively explained in the framework of a model for the AGMI response in amorphous wire taking into account effects of bias field induced by micro magnets.

The magnetic entropy change (ΔS_M) and magnetic properties of amorphous ribbons Gd_60-xHo_xFe₂₀Al₂₀ (x = 10, 30 and 50) have been investigated. The partial substitution of Ho for Gd results in a monotonously decrease of phase transition temperature from 165 K to 65 K and an increase of maximal ΔS_M from 5.44 J · Kg⁻¹K⁻¹ to 8.01 J · Kg⁻¹K⁻¹ under a field change of 0–5 T. Furthermore, a large value of relative cooling power (RCP) about 645 J.kg⁻¹ is obtained in Gd₁₀Ho₅₀Fe₂₀Al₂₀ amorphous ribbons. This material could be a very good candidate for magnetic refrigerant around the liquid nitrogen temperature region. It is also found that the amorphous ribbons with the same chemical composition fabricated at different spinning rate show the similar temperature dependence of magnetization behavior, the maximal ΔS_M as well as saturated magnetization, however, increases with the spinning rate. It could be attributed to the different rate of solidification of the alloy.

The structural and electrical properties of undoped CoFe₂O₄ and Co_1−xAl_xFe_1.8Ce_0.2O₄ (x = 0.3, 0.4 and 0.5) samples synthesized by sol-gel method is reported in this paper. The prepared ferrites were found to crystallize in cubic spinel structure as confirmed by x-ray diffraction study. Al substitution has resulted in appreciable decrease in the crystallites size. The dielectric constant (ε'), dielectric loss factor and AC conductivity of nanocrystalline cobalt ferrites were investigated as a function of frequency. Co_0.95Al_0.5Fe_1.8Ce_0.2O₄ sample is found to exhibit better dielectric properties compared to the other doped and undoped CoFe₂O₄, Impedance spectroscopy was utilized to analyze the microstructural contribution towards conduction, which confirms the dominance of the grain boundary effect. It is observed that increase in Al doping results in decrease of impedance z' owing to the relaxation process. Reduced dielectric loss values were observed for these ferrites. Thus Al-Ce doped cobalt ferrites with low loss find potential application in high frequency read/write memory devices.

We have investigated the structural, magnetic, and magnetocaloric properties of the nanocrystalline double perovskite Pr₂CoMnO₆ oxide prepared by the sol-gel method. The x-ray diffraction (XRD) using Rietveld refinement shows that the sample under investigation crystallizes into the orthorhombic crystal structure with Pbnm space group. The average crystallite size calculated using Debye-Scherer's formula was found to be ∼17 nm. The scanning electron microscopy image shows that the particles formed were of almost uniform in size with particle size ∼192 nm. The temperature dependence magnetization data shows that sample has a paramagnetic to ferromagnetic phase transition around 173 K. A series of M-H isotherms were performed at a gap of 10 K around transition temperature. The maximum entropy change (∣ΔS_max∣) was found to be 1.98 Jkg⁻¹ K⁻¹ at a field change of 5 T and relative cooling power (RCP) was calculated to be 110 J kg⁻¹. These obtained values are reasonably high and could be the potential material for magnetic refrigeration technology.

The growth of KZnF₃ single crystals doped with ∼0.2 mol% cobalt ions by an improved Bridgman method is reported. The crystal structure characterized by the x-ray diffraction (XRD) confirms a pure cubic structure for the obtained single crystal. The absorption spectra, excitation spectra, and emission spectra are measured to investigate the optical properties of the grown single crystal. The absorption peaks at 466 nm, 530 nm, 698 nm, and 1428 nm are observed. The absorption results confirm the valence of cobalt ions in the single crystal. The lattice parameters Dq, Racach parameters B and C of Co²⁺ ion in fluoride octahedron are also estimated.

Optical characteristics of butyl rubber/GPF carbon black (BR/GPFCB) composites with carbon black (CB) concentrations 40, 60, 80 and 100 phr (part per hundred part of rubber) were investigated. The structure of the BR/GPFCB composites was analyzed by x-ray diffraction (XRD). All samples with various CB showed diffraction peaks around 2θ = 14°, 25° and 44° which correspond to interlayer spacing of 6.23 Å, 3.62 Å and 2.10 Å respectively. The peaks were shifted toward larger 2θ angles with increasing CB concentration, indicating a decrease in layer spacing. Ultraviolet and visible (UV–vis) absorbance spectra in the range from 200 nm to 800 nm of the BR/GPFCB composites were studied. In the UV range of the spectra, an absorption edge was recorded. Direct and indirect optical band gaps for the composites were evaluated. The direct band gap values were found-as shown to be slightly greater than that of the indirect ones. The reflectance spectra in the UV optical range were demonstrated. Most of the incident UV light was absorbed inside the composites while a very small fraction was reflected and transmitted. This was attributed to the high UV absorption property of the CB filler. The refractive index of the composite was calculated from the reflectance data. The dependence of the real and imaginary parts of the complex dielectric constant on the incident light energy was characterized. The dielectric loss factor was found to decrease with increasing incident photon energy until approximately 5.5 eV (around the absorption edge) and then it increased rapidly.

This work reports a simple method for fabrication of highly sensitive photo-detector based on uniform nano-crystalline CdS thick films deposited on glass substrate by spray pyrolysis technique. The presented photo-detector platform contains CdS thick films (3, 6, 9, 12 and 15 μm) and Ag electrode structure. In order to detect incident light signals, changes in electrical signals were measured (conductance and current). For photo-detection, the current response between the 'ON' and 'OFF ' states of incident light was measured when exposed to different wavelengths ranging from 450 to 700 nm. The fabricated device showed significant detection of low-power (∼5 mW cm⁻²) light for optimized film thickness of 12 μm. Time response measurements at different wavelength show fast response and decay time (25 ms) and high photo sensitivity (1123) at low bias voltage, indicating good quality of the deposited 12 μm thick CdS film.

In this paper, a novel upconversion phosphor is reported. Based on XRD and EDS, it is confirmed that the phosphor is monoclinic Gd₂Mo₄O₁₅:Yb³⁺, Ho³⁺ with P21/c space group. The non-radiation decay of ⁵I₆ to ⁵I₇ dominants the depopulation of ⁵I₆, thus the phosphor produces the red upconversion emission with high emission intensity and good color quality, and shows the favorable temperature sensing property. When using non-continuous excitation mode, the temperature sensitivity is determined as 0.0452 K⁻¹. Because the sensitivity is the same at any temperature, the new upconversion material may have greater potential for temperature sensing application than Er³⁺ doped upconverison materials.

Photoluminescence spectra of ZnAl₂Se₄:Sm²⁺ due to the processes of charge carriers recombination from levels ⁵D_j, ⁵L_j, ⁵G_j and ⁵H_j (4f⁵5d¹) on levels ⁷Fj of samarium ions were investigated. The broad photoluminescence band at energies 1.6–1.9 eV due to optical transitions of electrons from 4f shell to 1s of samarium ions level was discovered. Emitted energy of it was absorbed by transitions from ⁷F_j to ⁵D_j levels. An up-conversion process—electron excitation from ⁷F_j levels to ⁵D₀, ⁵D₁, ⁵D₂ levels with simultaneous electron transitions to higher energy states ⁵D₃, ⁵D_4,⁵L_j, ⁵G_j, ⁵H_j with subsequent recombination to ⁷F_j levels with energy emission in short-wavelength region were found out and investigated.

In this study, inorganic perovskite CsPbBr_1.2I_1.8 quantum dots (QDs) were synthesized and their luminescence properties were investigated in detail. For the first time, a hybrid white light-emitting diode (LED) was fabricated by combining the Y₃Al₅O₁₂:Ce³⁺ phosphors (YAG) and liquid-type CsPbBr_1.2I_1.8 QDs with a blue LED chip. This liquid-type CsPbBr_1.2I_1.8 QDs-modified LED (LQD-LED) shows excellent optical performances with luminous efficacy (LE) of 91 lm W⁻¹, correlated color temperature (CCT) of 5112 K, and color rendering index (CRI) of 88, at an operation current of 20 mA. More importantly, the optical performances of the LQD-LED do not exhibit serious degeneration when the device is working under a higher operation current (350 mA) for longer operation time (100 h), which are superior to other solid-type QDs-modified LEDs (SQD-LEDs) reported previously. We believe that this liquid encapsulation structure LED would be applied to high-power lighting in the near future.

The crystal grown from mixing potassium iodide and zinc sulphate in an aqueous solution was found to be a single crystal potassium zinc sulphate hydrate. The iodide ions enter the crystal matrix as a dopant with small ratio. The evaluation of the crystal structure was achieved by single crystal diffraction and the resolved structure was monoclinic with space group P2₁/c. The effect of iodide doping is observed in the crystal morphology and the x-ray powder diffraction pattern. The iodide ions were detected in the grown crystal using x-ray fluorescence and energy dispersive x-ray which spotted a very small fraction of iodide in the raw materials of the crystal. The iodide doping also affected the thermal stability of the original crystal and introduced different thermal behavior. The optical properties are also affected and a noticeable band in the transmittance is observed. The iodide effect on the structure of optical energy gap is analyzed using photoluminescence spectra. Second harmonic generation test shows an unexpected behavior based on the structure of the grown crystal.

Sustained and efficient photovoltaic action depends on the electrolyte employed in the device like Quantum Dot Sensitized Solar cell (QDSSC). The study here focuses on the comparison of performance of different polysulphide electrolytes in CdS QDSSC by virtue of difference in their composition. Systematic electrochemical analyses were performed to study the effect of electrolyte composition on the overall solar cell performance by employing chronoamperometry, electrochemical impedance spectroscopy and electrical characterization of the fabricated solar cells. Of all the composition of electrolytes considered here, a modified polysulphide electrolyte with combination of ethanol, methanol and water has emerged as the best.

We present a temperature-dependent and time-resolved photo-luminescence (PL) study for few-layer tungsten diselenide (WSe₂) that is exfoliated from the bulk crystals. The PL intensities of direct and indirect exciton emissions in monolayer and bilayer WSe₂ decrease while temperature increases. However, abnormal enhancement of PL emission from direct and indirect excitons in ≥3-layer WSe₂ is observed at high temperatures, ranging from 300 K to 400 K. A crossover of Λ → Γ and Κ → Γ indirect transitions occurs in few-layer WSe₂ at elevated temperature and this phenomenon is verified by comparing the temperature-dependent shift of indirect exciton PL peak and ab initio band structure calculations. The enhancement of high-temperature PL from direct and indirect excitons can be attributed to the rapid intervalley transfer of thermally activated carriers from Λ point to K point and the crossover of Λ → Γ and Κ → Γ indirect transitions. The distinct behavior of temperature dependence of the PL intensities at a high temperature between bilayer and trilayer WSe₂ reflects their band structure discrepancy. This work provides a thorough understanding of the origin of the observed indirect optical transition in few-layer WSe₂ and suggests a possible means of improving the luminescence efficiency of multilayer WSe₂.

Aiming to broaden its application as wireless temperature sensors, a temperature-sensibility-enhanced Ba_1−xSm_2x/3(Zn_1/3Nb_2/3)O₃ (x = 0%–4.5%) ceramics with a large temperature coefficient of the resonant frequency have been prepared by conventional solid state reaction method. X-ray diffraction analysis shows that single-phase solid solutions are formed within x range of 0.37% to 3%. A minor substitution of Sm for Ba facilitates the enhancement of ε_r and τ_f, which is related to variations in polarizability and crystal structure. τ_f expands remarkably as x increases, indicating that Ba_1−xSm_2x/3(Zn_1/3Nb_2/3)O₃ ceramics could serve as a potential candidate for wireless passive temperature sensor application. Moreover, Photoluminescence and excitation spectra illustrate that Ba_1−xSm_2x/3(Zn_1/3Nb_2/3)O₃ exhibits luminescent properties. Although Raman spectra and scanning electron microscope studies reveal that excess Sm³⁺ dopant has destroyed the complex perovskite structure and generated secondary phase Ba₃Nb₂O₈, which have caused the deterioration of Q × f value, Sm³⁺ doped Ba(Zn_1/3Nb_2/3)O₃ ceramics paves the way to develop a promising multi-functional material utilized in temperature sensors and optical-electron integration devices in high frequency.

In this study, the pure TiO₂ nanoparticles and two kinds of hybrids including decorated TiO₂ nanoparticles with SnO₂ nanoparticles (A-S (1-1) and A-S (1-2)) are synthesized by hydrolysis method in order to evaluate the photocatalytic activity. The synthesized photocatalysts are characterized using FTIR. The photocatalytic performance is recorded by variation of the photodecomposition of methyl orange as an organic pollutant with respect to the pH of solution (pH = 3, pH = 7 and pH = 11), UV irradiation time (ranging from 5 min to 20 min) and weight fraction of photocatalysts (0.1%wt, 0.2%wt and 0.3%wt). According to the obtained results based on Duncan's multiple range test at α = 0.05, it can be confirmed that the variations of the removal efficiency with main factors are significant. Meanwhile, compared with TiO₂ nanoparticles, the photocatalytic activity of A-S (1-1) and A-S (1-2) enhances and it depends on the amount of decorated SnO₂ nanoparticles on the outer surface of TiO₂ nanoparticles. The kinetic investigation of the photocatalytic reactions reveals that the photocatalytic reaction rate constant (k_p) enhances with introducing the SnO₂ nanoparticles to the TiO₂ nanoparticles. Furthermore, based on the optimization results it is clear that the maximized values of removal efficiency using synthesized TiO₂ nanoparticles, A-S (1-1) and A-S (1-2) are 97.46%, 98.57% and 99.17%, respectively.

We study structural and optical properties of ZnO film prepared by pulsed laser deposition. The film was characterized by x-ray diffraction and UV–visible spectroscopies. We find that the as-grown film is mostly amorphous. After hydrogen-annealing treatment, the film is crystallized with lattice parameters of a = 3.241 Å and c = 5.203 Å. From UV–visible spectra, the low absorption edges of 1.44 and 1.43 eV are observed in the as-grown and annealed films, respectively, suggested to be promoted by some vacancies. Then, the generalized gradient approximation method is used to calculate electronic and optical properties of ZnO_0.94, and Zn_0.94O systems as the possible models of the annealed film. Properties ZnO is also calculated as the reference. Bandgaps of 0.75 and 1.73 eV are obtained for ZnO and ZnO_0.94, respectively. The larger bandgap of ZnO_0.94 is caused by the increase of Fermi level induced by Zn 4s electrons, leading to the n-type semiconducting behaviour. On the other hand, Zn_0.94O exhibits the p-type metallic behaviour caused by the decrease of Fermi level induced by O 2p electrons with a minimum interband transition (ΔE) of 0.95 eV. Then, a shift of ΔE is applied in the optical properties calculation for approaching the experimental results. From the imaginary part of dielectric function (ε₂(E)) for xy plane, ΔE of ZnO and ZnO_0.94 systems are 3.30 and 4.10 eV, respectively. The optical dichroism of ZnO_0.94 is smaller than that of ZnO. On the other hand, ΔE of Zn_0.94O is 1.80 eV based on ε₂(E) for z axis indicating the optical dichroism flip by the Zn vacancy in ZnO. The low absorption edge of the annealed film is promoted by the Zn vacancy. Furthermore, plasmonic-state energy levels in ZnO can be tuned by the O or Zn vacancies. This study shows the essential properties of ZnO for potential high-energy plasmonic device applications.

By employing poly(vinylidene fluoride) (PVDF) as matrix material, CaCu₃Ti₄O₁₂ (CCTO) as ceramic filler, and multi-walled carbon nanotube (MWCNT) as conductive material, MWCNT/CCTO/PVDF three-phase composites were fabricated through a solution blending-casting method. Micro morphology (by Scanning electron microscope, SEM), crystalline structure (by X-ray diffraction, XRD) and the dielectric properties of the materials were analyzed. SEM images show that the addition of MWCNT in composite materials promote CCTO well dispersed in the PVDF matrix. Nevertheless, excessive MWCNT will degrade the performance of materials. Dielectric property test results show that at room temperature and 100 Hz, when 30 vol% CCTO powder was used, CCTO/PVDF composite showed the optimal dielectric properties with dielectric constant 16.5 and dielectric loss 0.075, but there were still many holes and obvious flaw in the material. When 4.0 vol% MWCNT was added into above composite, the dielectric constant and loss of the three-phase composite were 55.733 and 0.251 respectively. Compared with CCTO/PVDF composite (0.617 J · cm⁻³), the energy storage density of MWCNT/CCTO/PVDF composite (1.395 J · cm⁻³) increased. The research shows that when the MWCNT content reaches the percolation threshold, the dielectric constant of composite materials increase dramatically and good comprehensive performance could be obtained.

In this work, the polyurethane (PU) foam is applied as restrict reaction vessel to synthesis of nanometer dimension Li-rich Manganese-based layered cathode material Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ (LMNCO). The PU foam has strong ability of absorbing mixed metal salt solution and keeping them in a relatively stable system during the freeze-drying process. Meanwhile, it supplies abundant three-dimensional interconnecting structure with macro-pore sizes of about 200–500 μm, which can be served as a sacrificial framework, obstructing the raw materials aggregation and supporting the products in the pre-sintering process. The results demonstrate that the facile method performed on PU foam could effectively suppress the growth of grains. Scanning electron microscopy indicates that the Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ particles have a size of 100–600 nm and mainly distributed between 200–300 nm. Moreover, it displays excellent cycle performance with high capacity retention rate of 85.3% after 100 cycles at a current density of 20 mA g⁻¹.

The properties of Polytetrafluoroethylene (PTFE) filled with two kinds of binary mixtures of silica particles with different size distribution (i.e., 2 μm + 15 μm and 5 μm + 15 μm) were investigated at a fixed total filler content of 62 wt.%. The effects of particle size distribution of silica on the properties of PTFE/SiO₂ composites were investigated, including density, moisture absorption, dielectric properties (ε_r, tan δ), coefficient of thermal expansion (CTE) and temperature coefficient of dielectric constant (τ_ε). Scanning electron microscopy results show that small size silica of appropriate content filled the holes between large size silica, contributing to compact microstructure. However, remarkable agglomeration of SiO₂ fillers was observed with too much small size silica and resulted in lower density. As the filler was comprised of 31 wt.% 2 μm and 31 wt.% 15 μm SiO₂, the composite showed a compact structure with a high density of 2.157 g cm⁻³. At the same time, optimal properties were obtained for PTFE/SiO₂ composite, including excellent dielectric properties (ε_r ∼ 2.99, tan δ ∼ 0.002), coefficient of thermal expansion of 18.68 ppm C⁻¹, acceptable water absorption of 0.05% and low temperature coefficient of dielectric constant of 11.43 ppm C⁻¹.

Phosphorene a two dimensional (2D) arrangement of black phosphorus atoms has greatly manifested extraordinary properties. In this work we investigated the electronic and mechanical properties of a deformed structural (i.e. modified two characteristic angles) single-layer black phosphorus using tight-binding (TB) Hamiltonian and Green's function approach, where a planar and a most puckered structure have been created by modifying the angle between two nearest neighboring P–P bond from two sublayers. Moreover, by using density functional theory (DFT), we show that the applied strain in the x, y axes and electric field can be used to tune the electronic properties of black phosphorene. We also provide a comparison of phonon vibrational modes of planar and puckered phosphorene to compare their structure stability. It was found that by structural deformation such as modifying the angle between two nearest neighboring P–P bond from two sublayers, consequently having a planar and a most puckered structure, no change can be seen for the effective masses along the y (zigzag) direction, but totally affected along the x (armchair) direction leading to heavier electrons and holes. Furthermore, 2D phosphorene exhibits different stiffness for applied strain in the x, y direction. Such rich variety of electronic, mechanical and structural transformations provides 2D phosphorene as a unique material for fundamental physics studies and applicable in nanoelectronic and nanophotonics devices.

The intrinsic counterclockwise hysteresis induced by the ferroelectric polarization is always concealed in Pb(Zr,Ti)O₃ (PZT) gated MoS₂ filed-effect transistors (FETs). Here, we observed the well-defined counterclockwise hysteresis in MoS₂ FETs with the Mn-doped PZT (Mn-PZT) dielectric layer. The evolution of hysteresis with varying the range of back-gate voltage (V_bg,max) was investigated. The good linear relation was obtained for hysteresis area (〈A〉) with varying V_bg,max. The similar variation tendencies were observed for memory windows (ΔV) of the FET and the coercive voltage (2 V_c) of the PZT film with increasing V_bg,max, indicating the memory windows were defined by the coercive voltages. The hysteresis behavior in this study was thought to be dominant by the intrinsic hysteresis effect of the ferroelectric polarization, which was discussed by the disappearance of the dead layer and the decrease of oxygen vacancies at the PZT/MoS₂ interface due to Mn doping.

Due to its excellent properties, Zn alloy is widely used in daily life. However, the poor wear-resisting properties of Zn alloys limits their application. In this paper, a tri-layer thin film consisting of 3-aminopropyltriethoxysilane (APS), graphene oxide (GO) and perfluoropolyethers (PFPE) were successfully prepared on the surface of Zn alloy to improve the wear-resisting properties. The as-prepared tri-layer thin films were characterized by atomic force microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy and contact angle measurement. In addition, the tribological properties of the as-prepared tri-layer thin films were studied on a ball-on-plate tribometer and the morphologies of worn surfaces were observed using 3D noncontact interferometric microscope. Compared with the control samples, the tri-layer thin films showed excellent friction-reducing and wear-resisting properties, which was attributed to the synergistic effect of the GO as the load-carrying layer and the PFPE as the lubricating layer.

A high quality lanthanum (La) doped cadmium sulfide (CdS) thin films were synthesized onto a glass substrates by chemical bath deposition. The effects of lanthanum doping concentration on the composition, structural and optical properties of CdS thin films have been studied. The transmittance of CdS thin film is 80% and gradually decreased as the La content was increased. Analysis of the optical absorption coefficient of CdS and La doped CdS thin films revealed that a presence of direct optical transition and the optical direct band gap of the films apparently decreased from 2.45 to 2.09 eV when the lanthanum content was increased from 0 to 12 wt %. The values of optical and electrical conductivity of CdS and La doped CdS thin films have been increases with increasing the lanthanum content. The self cleaning test shows that 12% La doped CdS thin films have excellent photocatalytic activity.

Three single-crystalline (Al₂O₃, GaN/Al₂O₃ and InAs) substrates are used to assist the formation of crystallographically preferred oriented CH₃NH₃PbI₃ (MAPbI₃) thin films. The estimation of the lattice mismatch at the MAPbI₃/substrate interface and water-droplet contact angle experiments indicate that the formation of a preferred oriented MAPbI₃ thin film is induced by the single-crystalline substrate and is insensitive to the surface wettibility of the substrate. Moreover, the experimental results suggest that the lattice mismatch at the MAPbI₃/single-crystalline semiconductor interface can strongly influence the photovoltaic performance of tandem solar cells.

Although the two-step sequential deposition method provides an efficient route to fabricate high performance perovskite solar cells (PSSCs) with increasing reproducibility, the inefficient and incomplete conversion of PbI₂ to perovskite is still quite a challenge. Following pioneering works, we found that the conversion process from PbI₂ to perovskite mainly involves diffusion, infiltration, contact and reaction. In order to facilitate the conversion from PbI₂ to perovskite, we demonstrate an effective method to regulate supersaturation level (the driving force to crystallization) of PbI₂ by solventing-out crystallization combining with subsequent time-delay thermal annealing of PbI₂ wet film. Enough voids and spaces in resulting porous PbI₂ layer will be in favor of efficient diffusion, infiltration of CH₃NH₃I solution, and further enhance the contact and reaction between PbI₂ and CH₃NH₃I in the whole film, leading to rapid, efficient and complete perovskite conversion with a conversion level of about 99.9%. Enhancement of light harvesting ranging from visible to near-IR region was achieved for the resultant high-quality perovskite. Upon this combined method, the fabricated mesostructured solar cells show tremendous power conversion efficiency (PCE) improvement from 3.2% to about 12.3% with less hysteresis owing to the simultaneous enhancement of short-circuit photocurrent density (J_sc), open-circuit voltage (V_oc) and fill factor (FF).

In the current study, functionally graded clads (FGC) of Ni-Cr₃C₂ based composite powders with varying percentage of Cr₃C₂ (0%–30% by weight) were developed on austenitic stainless steel (SS-304) substrate through microwave hybrid heating method. A domestic microwave oven working at 2.45 GHz and variable power level of 180–900 W was used to conduct the experimental trials. The exposure time was varied with compositional gradient and was optimized. Scanning electron microscopic (SEM) image of the FGC shows the uniform distribution of Cr₃C₂ particles inside the Ni matrix. Presence of Ni₃C, Ni₃Si, Ni₃Cr_2, and Cr₃C₂ phases was observed in the different layers of FGC. The top FGC layer exhibits the maximum value of microhardness of order 576 ± 25 HV which was 2.5 times more than that of the substrate.

The microstructure evolution of the 190 μm-thick Cu foils subjected to repeatedly bending loading was investigated. We found that the grains in the micron-scale foil were refined into subgrains with a size of about 0.5 μm through a removal of twin boundaries and an introduction of a high frequency of high angle boundaries (>15°) with accumulative cyclic deformation. With increasing strain rate (loading frequency), the grains are completely refined into well-defined fine grains with high angle boundaries. Such the microstructure refinement induced by accumulative cyclic deformation may provide a potential strategy for grain refinement of small-scale materials.

In this work, tin oxide (SnO₂), Sn_1−xIr_xO₂ (0.025 ≤ x ≤ 0.05) and Sn_0.95−yIr_0.05Ni_yO₂ (0.025 ≤ y ≤ 0.075) thin films were synthesized by a sol-gel spin coating technique. XRD results showed that the films are of polycrystalline rutile structure with crystallite size <31 nm. Raman and FTIR spectra are significantly affected by the type and concentration of dopant atoms. AFM measurements illustrated that the surface of the films have pores of circular shape and both the pores diameter and surface roughness depend on the dopant type. EDS confirmed the substitutional replacement of Sn ions by Ir and Ni in the host lattice. Films densities demonstrate the effect of Ir and Ni on the growth rate. Ultrasonic studies by pulse-echo technique are applied for the first time to investigate the mechanical properties of these films. (Ni, Ir) double doped SnO₂ thin films had more pores, less grain agglomeration, less cross-link density and less rigidity. The transmittance spectra and the optical band gap of the films can be tuned by Ir and (Ni, Ir) doping. According to the obtained results, the doped films can be potentially used for different optoelectronic applications as well as for gas sensing.

In this work, we have investigated the influence of different zinc precursors and different Cu/(Zn+Sn) stoichiometries (1.4, 1.19 and 0.92) on the structural, morphological, optical and electrical properties of the solution derivable Cu₂ZnSnS₄ (CZTS) thin-films by using dip coating technique. X-ray diffraction (XRD) results pointed out that the CZTS thin films crystallized in the kesterite structures with (112) preferred orientation. It was founded that the peak intensity of zinc acetate based CZTS thin films was twice as severe as zinc nitrate based. It was also observed that changing Cu/(Zn+Sn) stoichiometry resulted in a highly improved crystallinity of the thin films. Scanning electron microscopic micrographs exhibited a remarkable improvement in size and morphology depended on using zinc precursor and Cu/(Zn+Sn) stoichiometry. Optical analyses showed that the absorption intensity was higher in zinc acetate based CZTS thin film than that of the zinc nitrate based CZTS film. Among all the CZTS films the highest absorption was observed for the Cu/(Zn+Sn) stoichiometry of 1.4. UV–vis spectra analyses showed a direct band gap varying from 1.64 to 1.9 eV, which upon on the used zinc precursor and Cu/(Zn+Sn) stoichiometry. The computed optical constants showed a high dependence on the zinc precursors and different Cu/(Zn+Sn) stoichiometries. Hall measurements confirmed p-type conductivity and the electrical properties of the films were considerably changed with respect to the zinc precursors and Cu/(Zn+Sn) stoichiometries. According to the observed results the zinc acetate based CZTS thin films with Cu/(Zn+Sn) stoichiometry of 0.92 has promising potential for thin film solar cell applications.

Nowadays, the demand of polymer based composites with high thermal conductance is rapidly increasing. Thermal conductive acrylate pressure sensitive adhesives are widely studied due to their excellent ageing resistance, light resistance, water resistance, oil resistance and broad application field. In this work, thermal conductive pressure sensitive adhesives with excellent comprehensive performances have been prepared from acrylate pressure-sensitive adhesive (matrix) and aluminum oxide/aluminum nitride particles (fillers). The influences of the class, loading content and grain size of fillers on heat conductivity, electric insulation and mechanical features of composites were deeply researched. High dispersion of fillers in matrix could be obtained by surface modification of fillers using silane coupling agent and polymethyl methacrylate. Heat conductivity of composites was improved with increasing of filler content and sharply elevated at a critical filler content. As filler content was increased, electric insulation trait was reduced but still kept at a relatively high level. High filler content was harmful to mechanical property. Fortunately, the composites with hybrid fillers of varied grain sizes were found to have significantly promoted thermal conducting, electric insulating and mechanical performances in comparison with single filler of one size. That might be ascribed to synergistic effect of both fillers with varied grain sizes. Finely balanced comprehensive features were achieved at a weight ratio of 3:7 (small size filler/large one). High heat conductivity (∼0.83 W m⁻¹K⁻¹), breakdown voltage (∼1.9 kV) and 180° peel strength (∼8.3 kN m⁻¹) were obtained. This work might open the door to the large-scale fabrication of high-performance thermal conductive acrylic pressure sensitive adhesives based on size effect of hybrid fillers.

Laser texturing with a nanosecond pulsed Nd³⁺:YAG laser in air and water is used to create surface textures in a-Si thin films based on the laser beam overlap technique that enhances light-trapping along with simultaneous crystallization and defects passivation. The light-trapping characteristics of textures are analyzed by optical reflectance measurements and the influence of crystallinity and light trapping textures on electronic properties are studied using I-V characterization and the results are compared with theoretical analysis. The theoretical analysis is performed based on the actual surface geometry of the textured surface, characterized by an atomic force microscope. Finite element analysis approach is used to solve the Maxwell's equations in two dimensions to analyze wave propagation within thin-film. The influence of texture base and height of the texture profile is studied to obtain the texture dimensions for enhanced efficiency. Theoretical simulation studies clearly show that light trapping efficiency is significantly enhanced with the textured surface and the highest efficiency is obtained with the texture height of approximately 300 nm or more irrespective of the base diameter. More than 95% of light is absorbed at incident angles up to 60°, which is higher than flat thin films (∼49%). Experimentally measured reflectance values shows reduction in reflectance from 43% to 14% when optimal height is achieved by treating the samples with 30% and 50% spot overlap.

Al₂O₃ and WC-Co water-based epoxy resin(WER) coatings for corrosion protection of TC18(with the composition of Ti-5Al-5Mo-5V-1Cr-1Fe) are prepared by air spraying. Two kinds of coating are investigated by scanning electron microscopy and x-ray diffract meter, adhesion evaluation is conducted by grid test. The results show that the coatings are continuous without defects and the level of adhesion up to 4B according to the standard of ASTM D3359. Neutral salt spray test of 750 h is carried out and corrosion resistance is measured by potentiodynamic polarization studies and electrochemical impedance analysis. The corrosion potential and corrosion current density of the WC-Co-WER coating are −0.139 V, 2.520 × 10⁻⁸ Acm⁻², respectively, and Al₂O₃-WER coating are −0.195 V, 2.891 × 10⁻⁸ Acm⁻², respectively. The protective efficiency of the WC-Co-WER coating is 87.6%, which is higher than that of the Al₂O₃-WER coating with 85.8%. Epoxy resin has good corrosion resistance, the surface of WC-Co-WER coating has more epoxy resin due to sedimentation of the WC-Co particles, WC-Co particles concentrate inside the coating retard infiltration of the corrosive. The above characteristics made the WC-Co-WER coating perform better in corrosion resistance.

MEMS (micro electro-mechanical systems) operated in resonance and excited piezoelectrically are nowadays used for a broad range of different application scenarios. To enhance the process stability and hence, the reproducibility of key film parameters of sputter-deposited aluminium nitride such as the film stress, the piezoelectric coefficient d₃₃ and low leakage current levels, a novel aluminium clamped substrate holder is reported. Compared to the standard molybdenum based solution, where the thermal contact between the wafer and substrate holder varies during deposition, as the wafer can move freely, the substrate temperature variations are substantially reduced due to clamped configuration. Independent of AlN film thickness ranging between 0.5 μm and 2.0 μm the scatter in piezoelectric constant d₃₃ and leakage current characteristics represented by the barrier height and the activation energy is reduced up to a factor of 3. These results demonstrate the importance to control carefully the temperature conditions during low-temperature AlN deposition to ensure a high reproducibility in film properties.

The fabrication of pure and yttrium doped (2 mol % and 6 mol %) ZnO thin film by RF sputtering for room temperature ammonia sensing is reported. Among these, 2 mol % yttrium doped ZnO thin film sensor shows high sensitivity, quick response, and recovery time due to high surface to volume ratio observed from Scanning Electron Microscope (SEM). It was also well supported by x-ray diffraction (XRD), Hall effect measurement and Photoluminescence (PL) studies. The repeatability measurement also confirmed that the 2 mol % yttrium doped ZnO is effective material for room temperature ammonia sensing.

The detection of aflatoxin B₁ (AFB₁) using immunoassays, especially electrochemical immunoassays, is fast, sensitive and efficient. In this study, 2-aminoethanethiol was used to enhance the speed and sensitivity of conventional electrochemical immunoassays for AFB₁ detection by assembly on the surface of a Au electrode, forming self-assembled monolayers (SAMs). Then, non-competitive immunoassays occurred on the modified electrode surface forming an electrochemical immunoassay sensor. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy were used to examine the state of the SAMs, and an electrochemical workstation was used to monitor the current change of the electrochemical reaction, so as to characterize the designed immunosensor. Our experimental results shows that, the 2-aminoethanethiol reagent was successfully assembled on the Au surface through Au-S bonding and the –NH₂ terminal group faced outward. Herein, the minimum concentration of AFB₁ which caused a significant current change was 0.01 ng mL⁻¹. The prepared immunosensor also exhibited excellent stability and sensitivity after storage for 7 days or upon regeneration.

Highly transparent conductive ITO coatings with transparency ≥80% and resistivity ∼2.8 × 10⁻⁴ Ωcm are prepared directly by substrate heating using an advanced 3D confined high-density magnetron source (3DMS). The deposited ITO films exhibit excellent carrier concentration, mobility, and crystallinity at a moderate substrate temperature and without post-annealing. Data reveals that the combination of very high-density plasma at a low electron temperature and moderate substrate heating is favorable for developing ITO materials for transparent electrode applications. The electrical, optical, structural, and morphological properties of the deposited films are investigated in details in light of the plasma chemistry and substrate heating.

A simple and inexpensive spray pyrolysis method has been employed to synthesis a reproducible pure and F:CdS thin films onto a pre-heated glass substrate. The x-ray diffraction studied reveals that the sprayed pure and F:CdS films exhibit cubic structure. The optical parameters of the sprayed pure and F:CdS films such as the linear refractive index n as well as the optical band gap, E_g were evaluated as a function of the F doped content. The dispersion parameters of the sprayed pure and F:CdS films were used to determine the nonlinear optical susceptibility, χ⁽³⁾ and non-linear refractive index n₂ as a function of the F doping content in CdS. The sprayed 8 wt% F:CdS thin film exhibit a highest values of the bsorption coefficient and optical conductivity as compared to other films. Thus, the concentration of 8 wt% F:CdS has been chosen to fabricate the Al/p-Si/F:CdS/Au heterojunction. The addition of fluorine to the CdS films raises the efficiency of the fabricated heterojunction from 1.92 to 2.63%.