Table of contents

Research involving lignin use is not new. For many years, the macromolecule was underestimated in its potential and burned for energy use in pulp and paper industries. However, with the advent of biorefinery on the valorization of lignocellulosic fractions, lignin is receiving greater motivation to be researched. Of the many applications, the most profitable one is its conversion into carbon fiber. Lignin-based carbon fibers can reduce the manufacturing price of this fiber to values greater than 35%, besides using a renewable material with a highly sustainable appellation. This paper gives an overview about lignin-based carbon fiber comparing the process to current precursors, presenting different pathways on different research, pointing to the most common difficulties and assessing new findings. A gap not fully clarified yet is concerning the lignin structure and its relation to extrusion process. After isolation procedures, lignin repolymerizes in a different manner compared to when it is in its natural form. Some studies have shown that some organic functions, the molecular weight and the structure conformation of the lignin can favor or disfavor thermal mobility. Although it is known purification is considered a criterion that favors extrusion, there is no study involving a selection of parameters that improves thermal mobility. Herein, it is highlighted a set of desired structure properties that provides a very good thermal mobility and extrusion in order to obtain a lignin-based carbon fiber with good properties.

Calcium copper titanate (CCTO) sputtering target was synthesized by solid state method. Structural analysis of target has confirmed the formation of CCTO phase. CCTO thin films were deposited by RF magnetron sputtering technique on p-Si (100) substrates with the working pressure and RF power of 5 × 10^–3 mbar and 105 W, respectively. Post-deposition annealing was performed at different temperatures ranging from 650 °C to 950 °C. Evolution of CCTO polycrystalline peaks has been observed in the 950 °C annealed film. The formation of CCTO phase has also been confirmed by FTIR spectroscopy studies. The surface morphology of the annealed thin film was found to be modulated with the annealing temperature. Larger microstructures have been found for the films annealed at high temperature. Bandgap of films were calculated from UV–vis spectral analysis. Electrical properties of the annealed thin films were studied by fabricating Al/CCTO/Si MOS structures. The interface trap density (D_it) was calculated as 7.9 × 10¹⁰ eV⁻¹ cm⁻² for the films annealed at 950 °C. Improved bipolar resistive switching behavior has been observed for the films annealed at 950 °C.

The potential of TiO₂ is greatly understood in diversified fields of science and technology. With the advent of nanotechnology, the study of nanofluids has gained significant attention. The physical properties of a fluid can considerably be varied with nanoparticle incorporation. The present work describes methods for controlling the thermal diffusivity of TiO₂ nanofluid. The thermal diffusivity of the nanofluid is measured by single beam thermal lens technique. TiO₂ nanoparticles synthesized by sol–gel method with different amount of oxalic acid and the sample calcined at different temperatures are analyzed by x-ray diffraction (XRD) technique. The field emission scanning electron microscopic (FESEM) image and XRD analysis confirmed the particle formed to be nano in size. The transformation of phase from anatase to rutile with temperature and the amount of oxalic acid is studied from the XRD pattern. The thermal lens study of the samples reveals that the thermal diffusivity increases with temperature and amount of oxalic acid. The study also suggests the possibility of controlling the thermal diffusivity of TiO₂ nanofluid through phase tuning.

We propose a multilayer structure alternately stacked by graphene, silicon carbide (SiC) film, and hexagonal boron nitride (hBN) bulk to theoretically study the near-field radiative heat transfer. Compared with blackbody result, the heat transfer coefficient (HTC) can be significantly enhanced due to the effect of surface plasmons (SPs), surface phonon polaritons (SPhPs), and hyperbolic modes (HMs) supported by graphene, SiC, and hBN, respectively. HTC between the proposed structures with thin SiC can even be larger than that of graphene-covered hBN. Since SPs could be coupled both with HMs supported by the hBN and with SPhPs supported by SiC, HTC can be flexibly modulated by chemical potential of graphene. In addition, HTC of another structure which is composed with graphene, hBN film, and SiC bulk in order is also investigated in detail. The impacts of the thickness of components and vacuum gap on HTCs for both configurations are also studied. The results in this study are helpful to control near-field radiative heat transfer.

In this work, Fe₃O₄/MWCNT nano-hybrid was successfully fabricated. Its composition, structure and morphology were characterized by XRD and TEM and the results suggested that Fe₃O₄ nanoparticles with cubic structure was smoothly dispersed on MWCNT surface. Electrochemical impedance spectra (EIS) showed that Fe₃O₄/MWCNT presented excellent electron transfer behavior. The electrochemical determination of phenol in phosphate buffer solution (pH 7.4) revealed that Fe₃O₄/MWCNT modified GC electrode (Fe₃O₄/MWCNT/GCE) exhibited superior catalytic activity toward phenol with a linear equation of i_pa (μA) = −0.018 − 0.034c (μmol/L) R = 0.9990 in a wide range from 5 to 235 μM. The detection limit was calculated to be 4.83 μM (S/N = 3) and a high sensitivity of 481.2 μA mM⁻¹ cm⁻² was achieved from the equation slope. This electrocatalyst also showed a short response time and high anti-interference to ethanol. The wide detection range, fast response, low detection limit, high sensitivity and anti-interferance of Fe₃O₄/MWCNT endowed it with potential application in electrochemical detection of phenol.

A simple hydrothermal method was developed in this study to synthesize hydrophobic calcium sulfate hemihydrate whiskers in the presence of stearic acid. The morphology of the whiskers synthesized under different conditions was characterized by scanning electron microscopy, and their average aspect ratio was also estimated. The optimum synthesis conditions are determined as follows: the concentrations of Na₂SO₄ and CaCl₂ solution for preparing the precursor are 1.1 mol L⁻¹; the precursor content in the autoclave is 10 wt%; the hydrothermal reaction temperature is 150 °C; and the hydrothermal reaction time is 4 h, respectively. Glycol was used to promote the dispersion of stearic acid in the seriflux. The results show that the hydrophobic calcium sulfate hemihydrate whiskers can be obtained with stearic acid as surfactant, and their average aspect ratio can reach about 91.

The electronic performance of graphene is largely related to its morphology, surface, size and various synthesis conditions, mainly because of the presence of grain boundary. Better understanding on the relationship between the size and electronic property is very important for graphene's applications in potential electronics. Herein, we selectively synthesized single-crystal graphene using a chemical vapor deposition (CVD) method. The obtained CVD-graphene exhibited various sizes, ranging from 20 μm to 120 μm. Our measurements of field effect transistor devices revealed that the charge carrier mobility of CVD-graphene could increase from 17.8 to 720 cm² V⁻¹s⁻¹ with the size decreasing. The better electronic performance in comparable smaller-size graphene was ascribed to less grain boundary compared with the bigger one, which was further confirmed by our observations from scanning tunneling microscope/spectroscopy (STM/STS).

Although extremely high specific capacity has been envisioned for Si anode materials, the application of Si in lithium-ion batteries (LIBs) is still hampered due to the rapid capacity fading mainly caused by the huge volume changes during the cycling. In this study, carbon-coated Si particles with self-supported Si nanowires were prepared using low-cost raw materials by a versatile and scalable method and investigated as anode materials in LIBs. The single Si particle with size of about 30 ∼ 40 μm is composed of a solid Si core and numerous porous Si nanowires radially distributed on the Si core. This unique architecture can effectively accommodate the volume expansion of Si, release the mechanical stress, prevent the aggregation of Si nanowires and keep the structural integrity. Utilized as anode materials for LIBs, the as-prepared carbon-coated Si particles show improved cycle stability and high initial coulombic efficiency than the raw metallurgical Si particles.

A functionalized organic-inorganic hybrid is synthesized by Mannich reaction after its activation with organosilane coupling agent and subsequent conjugation with and 1-napthyl-2-thiourea (ANTU). The material is characterized by fourier transform infrared spectroscopy, elemental and thermogravimetric analysis. Its efficacy as adsorbent is tested for the extraction of low level of mercury from aqueous solutions using radiotracer technique. Various parameters affecting mercury extraction are optimized. Maximum sorption (92%) of Hg(II) ions occured at pH 6 in 30 min using 50 mg of nanohybrid as extractant. In competitive environment only chromate and fluoride increased while thiosulfate reduced its extraction efficiency. The mercury adsorption process is chemisorption in nature and follows second-order kinetic model. The sorption follows Freundlich and D–R models over a wide range of concentration studied. The maximum uptake capacity of the material is 156.7 mmolg⁻¹.

The present work was focused on formulation and characterization of toluene diisocyanate cross-linked β-cyclodextrin nanosponges as a pH-sensitive and an effective carrier for naproxen. The inclusion complexes of naproxen were prepared by physical mixture, kneading method with β-cyclodextrin and polymer condensation method with β-cyclodextrin-based nanosponges. Particle size of the inclusion complex formulations was found in the range of 378.45 ± 7.54 nm to 1520.47 ± 7.96 nm with low polydispersity index. Zeta potentials of the formulations were sufficiently high and showed poor tendency to aggregate. In-vitro and animal studies showed the prolonged release of naproxen from carrier for 1 day. Instrumental studies like FTIR and DSC studies revealed the interaction of naproxen with nanosponge structures. XRPD study showed the change in crystalline to amorphous nature of naproxen by complexing with nanosponges. Thus, toluene diisocyanate cross-linked β-cyclodextrin-based nanosponges act as a pH-sensitive and an effective carrier for controlled delivery of naproxen for anti-inflammatory action.

Paramagnetic Mn:CdS nanoparticles were synthesized by a colloidal method in a nonpolar solvent. The temperature and duration of synthesis were varied. The sizes of synthesized nanoparticles were determined by x-ray diffraction and dynamic light scattering in a crystal state and in an organic solvent. How optical (electronic absorption and luminescence spectra) and magnetic properties of synthesized compounds change with the reaction conditions were studied. A longer synthesis intensifies the migration of manganese ions from the bulk phase of nanoparticles to their surface. This effect is confirmed by changes in electron paramagnetic resonance spectra which characterize the ratio between different types of manganese ions and the shift of luminescence peaks to a shorter wave range.

One of the ways to improve the corrosion resistance of nanomaterials is the use of ionizing radiation for directional modification of structural properties. The paper presents results of directional modification of nanostructures using flows of low-energy electrons to change the structural properties of Cu nanotubes. Also, we present the dependence of the degradation degree in various aggressive media and time in a medium. The greatest deterioration in crystallographic characteristics of unmodified nanostructures in corrosive media is observed on the day 10th, which is due to partial destruction of the crystal structure as a result of oxidation processes. Also, an increase in the oxygen concentration in the structure leads to an increase in disorder regions, amorphization, and subsequent destruction of samples. Modified nanostructures exhibit a low rate of degradation. It is caused by a change in defects concentration after modification by an electron beam. Such a modification leads to an improvement in structural properties, a decrease in amorphous inclusions, and an increase in materials resistibility to corrosion and degradation. Analysis of the kinetics of structure failure as a result of aggressive media influence on the crystal structure of nanotubes showed that in the case of preliminary modification of nanotubes by an electron beam, nanostructures stability to degradation increases 8.33 times, which is confirmed by SEM and XRD data. The nature of the anamorphosis processes of degradation showed that for modified nanotubes a slower rate of degradation is observed. This indicates a promising possibility of using pulsed low-energy electron beams for directional modification of the crystal structure of copper nanotubes.

We report the sol–gel preparation of NiO films and their reduction to form nanoporous nickel films on glass substrate. Consisting of densely packed nanoparticles, the as-prepared NiO films are smooth and uniform. Nickel films with a nanoporous network-like structure are formed upon reductive annealing of NiO in hydrogen. The porosity of the nickel films is about 50%. The width of the pore is ca. 100 nm, and its length can reach hundreds of nanometers. The formation mechanism of nanoporous nickel films can be explained by the dewetting of nickel on a glass substrate driven by surface energy minimization.

In the present study, silver and copper nanoparticles were synthesized by using chemical reduction method. TGA was used to know the thermal stability and it was found that silver nanoparticles were more stable than copper nanoparticles. It was also observed from thermogram that copper nanoparticles gained small weight at 450 °C due to oxidation. DSC curves showed the peaks of endothermic and exothermic reactions that indicated the chemical changes inside nanoparticles. RD peaks demonstrated the face centered cubic crystal structure with crystallite size 15.13 nm and 14.45 nm of silver and copper nanoparticles, respectively. XRD also showed the partial oxidation of copper nanoparticles (Cu₂O). Spherical morphology with average grain size ranging 120–300 nm of silver nanoparticles and 150–350 nm of copper nanoparticles was observed by SEM. It was found that silver and copper nanoparticles are significant antibacterial agent against common human pathogenic bacteria like Staphylococcus aureus and Escherichia coli. It was observed that antibacterial activity increased as concentration of samples increased. Maximum zone of inhibition was observed by silver nanoparticles at concentration 0.24 g ml⁻¹. Copper nanoparticles results were comparable with silver nanoparticles against S. aureus but showed slightly less antibacterial action against E. coli. It was observed that silver nanoparticles were more reactive to inhibit the growth of bacteria as compared to copper nanoparticles.

In this work we studied the influence of particle size and agglomeration in the performance of solid oxide fuel cell cathodes made with nanoparticles of La_0.8Sr_0.2MnO₃. We followed two synthesis routes based on the Liquid Mix method. In both procedures we introduced additional reagents in order to separated the manganite particles. We evaluated cathodic performance by Electrochemical Impedance Spectroscopy in symmetrical (CATHODE/ELECTROLYTE/CATHODE) cells. Particle size was tuned by the temperature used for cathode sintering. Our results show that deagglomeration of the particles, serves to improve the cathodes performance. However, the dependence of the performance with the size of the particles is not clear, as different trends were obtained for each synthesis route. As a common feature, the cathodes with the lowest area specific resistance are the ones sintered at the largest temperature. This result indicates that an additional factor related with the quality of the cathode/electrolyte sintering, is superimposed with the influence of particle size, however further work is needed to clarify this issue. The enhancement obtained by deagglomeration suggest that the use of this kind of methods deserved to be considered to develop high performance electrodes for solid oxide fuel cells.

A simple and inexpensive one-step laser cladding method is reported to make the stainless steel mesh underwater superoleophobic. The micro/nanoscale morphologies were created via cladding a copper foil onto the stainless steel mesh using the nanosecond laser marking system. The fabricated stainless steel mesh has the underwater superoleophobic property with oil contact angles greater than 150°. Based on the special wettability, the fabricated stainless steel mesh is used to separate the light oil–water mixtures, and the separation efficiencies are >98.3%.

Tungsten trioxide (WO₃) has been investigated extensively because of its photochromic and electrochromic properties, which allow its color to be changed easily under various conditions. This research reports the pressure-induced chromism of WO₃ nanoparticles under pressures from ambient pressure to 31.8 GPa, in an effort to establish the pressure-structure-coloration relationship of WO₃ nanoparticles. In situ Raman spectra were used to evaluate the phase structures; and in situ UV–vis absorption spectra were utilised to characterise the coloration performance of the WO₃ nanoparticles. The phase transition and coloration characteristics of the nanoparticles were investigated in comparison with microcrystalline WO₃, based on the Raman results, and a series of phase transition sequences, associated with irreversible color change, was observed under different pressures.

In this paper, nonlocal free longitudinal vibration of thick nanorods is investigated by focusing on the inertia of lateral motions and shear stiffness effects. To this end, Bishop and nonlocal theories are used. Then, by implementing the Hamilton's principle nonlocal governing equation of motion and boundary conditions are derived. The governing equation is solved analytically for fixed-fixed and fixed-free end conditions and the first five longitudinal natural frequencies of nanorod are obtained. In the next step, effects of various parameters like the length of nanorod, the diameter of nanorod and the nonlocal parameter value on natural frequencies are investigated. This study can be a useful reference for modeling of the multi-walled carbon nanotubes in which the interlayer shear plays a significant role in their various mechanical behaviors.

An analytical route containing solid-phase extraction combined with dispersive liquid–liquid microextration (SPE–DLLME), was established to determine Cd ions in water samples. In this regard, Graphene oxide/polyaniline nanocomposite was synthesized through chemical method and then the graphene oxide/polyaniline nanocomposite was characterized by using XRD, FESEM, FTIR and TGA techniques. The prepared nanocomposite was investigated as a adsorbent in the presence of chelating dithizone ligand in solid phase extraction with dispersive liquid-liquid microextraction and used to measure cadmium (II) ions in aqueous media. In this method, firstly; single-variable parameters such as the amount of adsorbent, extraction time, type of desorption solvent, desorption time were investigated. Then, with using the design of expert, the parameters affecting the extraction efficiency such as the effect of salt addition (ionic strength), pH, volume of extraction solvent and the volume of dispersive solvent have been optimized. The analytical figure of merit such as limit of detection (0.1 μg L⁻¹), limit of quantification (0.4 μg L⁻¹), linear dynamic ange (0.4–1000 μg L⁻¹), repeatability (%1.3), enrichment factor (210) and relative recovery percentage (99%), were obtained for cadmium (II) spike aqueous samples. Finally, the method was successfully used and evaluated for the extraction and quantification of Cd ions from real samples and relative recoveries varied from 91%–107%.

In order to study the structural, surface morphological and dielectric properties of La_1−xFe_xMn_1−yGd_yO₃ for x = 0, 0.25 and y = 0, 0.04, 0.06, 0.08, nanocrystallites have been synthesized by sol-gel auto combustion method. The x-ray diffraction (XRD) patterns reveal that the structure of crystallite size increases by increasing the Gd concentration. The unit cell volume decreases by the substitution of 25% Fe, while the unit cell volume increases by the substitution of Gd upto 8%. The Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectra show the formation of Mn–O–Mn bonds which are related to the MnO₆ octahedron and confirm the existence of ABO₃ perovskite characteristic vibration. Field emission scanning electron microscope (FESEM) results show that Fe and Gd influence the surface morphology of the samples and the samples with 8% Gd concentration causes the agglomeration of particles. Energy Dispersive x-ray (EDX) Spectroscopy plot shows the presence of all the elements and EDX plot of all the samples strongly match with a standard values of La, Fe, Mn, Cl and oxygen (O). LCR meter data tells that by increasing concentration of Gd in LaMnO_3, dielectric constant and dielectric loss factor of samples increase. Impedance analysis reveals that total impedance of the material decreases with the increase of Gd doping. Complex impedance analysis has been explored by the cole-cole plot to examine the involvement of grain, grain boundary, and interfacial effects individually. Cole-cole plot indicates that Gd doping reduces the grain boundaries and forms a large semicircle.

Here, we present a facile microfluidic pathway for the rapid synthesis of uniformly sized TiO₂ nanoparticles (≈10 nm) using an inexpensive acrylic based microreactor, fabricated via time and cost effective LASER engraving technique. The design and dimensions of the microchannels were optimized to generate uniformly sized micro-droplets by means of hydrodynamic flow focusing process. Applied synthetic methodology is simple enough to be free from the use of any surfactant or capping agent otherwise used for the same. Further, we have investigated photocatalytic dye degradation in a continuous flow microreactor with TiO₂ embedded microchannels and observed a very high rate constant of photocatalysis (3.60 h⁻¹) with a maximum degradation efficiency of ≈89% against Methylene Blue dye within just 30 min of UV radiation. Thus, this work highlights the suitability of low-cost microfluidic reactors for the controlled synthesis of nanostructured materials and their application in photocatalytic dye degradation.

Dye-sensitized ZnO nanowire (NW) electrodes were fabricated using Ru polypyridyl complexes that use nitrile instead of carboxylic group as anchoring unit to the NW surfaces. The complexes formula is [Ru(bpy)_3−x(Mebpy-CN)_x]²⁺ (x = 1−3, bpy = 2,2'-bipyridine, Mebpy-CN = 4-methyl-2,2'-bipyridine-4'-carbonitrile). The ZnO NWs were grown by a vapor transport method on insulating SiO₂/Si substrates. The sensitized ZnO NW electrodes were studied by electron microscopy, Raman and PL spectroscopies, and spectral and relaxation photocurrent measurements. The Raman spectra confirm that the complexes were effectively anchored to the ZnO NWs through one of the pendant nitrile groups of the bipyridyl ligands. The nanostructured morphology of the NW electrodes was maintained so that their light trapping characteristics were preserved. The Ru complexes were found to be excellent sensitizers of the ZnO NWs, improving by orders of magnitude their photocurrent in the visible region. The Fe-based complex of formula [Fe(Mebpy-CN)₃](PF₆)₂ was also tested; however it did not show any sensitizing effect. An order of magnitude shortening of the persistent photocurrent relaxation times (after the illumination is interrupted) was found to occur upon successful sensitization of the ZnO NWs with the Ru complexes. This effect is interpreted in terms of hole traps at ∼1 eV above the ZnO valence band edge, which are lowered by ∼50–60 meV in the soaked samples due to screening of the trap centers provided by the extra photoexcited charge carriers transferred from the sensitizing complex to the NWs.

Zinc oxide (ZnO) films of nanograins were obtained on a glass substrate by simple and rapid chemical bath deposition method with zinc nitrate and urea as precursors at low pH condition (∼9) without adding any complexing agent. The structure, morphology and surface chemistry were confirmed from the XRD, EDX, Raman spectroscopy, x-ray photoelectron spectroscopy, BET, FE-SEM and TEM imaging measurements. Chemiresitive selectivity and sensitivity of ZnO film sensor toward NO₂ gas was better than other target gases like methanol, ethanol, hydrogen sulphide and chlorine. Remarkable high sensitivities from 176% to 610% towards NO₂ gas have been obtained under variation of concentration from 10 ppm to 200 ppm @200 °C operating temperature. Large response about 84.42% against first day measurement on 15th day supports chemical stability and mechanical robustness of ZnO film-based sensor. Hence, the present study signifies the potentiality of ZnO in fabricating low-cost and high-performance NO₂ gas sensors.

The present study makes the first attempt to introduce a comprehensive non-classical model of nonlinear free vibration of piezoelectric functionally graded (P-FG) nanobeam exposed to hygro-magneto-electro-thermal environment using the extended theory of piezoelectricity. Initially, by employing Von Karman geometric nonlinearity and Hamilton's principle, nonlinear governing equations and related boundary conditions are obtained. The Galerkin method combined with Ritz averaging technique is utilized in order to achieve the frequency response of nanobeams for various boundary conditions under different environmental conditions. The numerical results are first validated with well-known literature which are shown to be in complete agreement. Eventually, with the aid of several numerical examples, the effects of various parameters including power law index, nonlocal parameter, aspect ratio, voltage, temperature change, moisture and magnetic field are investigated.

Quantum mechanical calculations are performed for double-walled and triple-walled carbon nanotubes (DWCNTs, TWCNTs). We show how the DWCNTs may be modelled by mechanical analogues with interactions mediated by spring forces with weakening elastic constants in addition to a weak van der Waals -like interaction. This enables us to predict the natural frequency of longitudinal oscillations of the DWCNTs, their elastic spring constant and the corresponding interaction between the CNTs. Results of the interaction energy ΔE for the DWCNT system obtained from the mechanical model are in remarkable agreement with those obtained from our quantum mechanical calculations, and we obtain functional dependencies of ΔE on axial elongation and inter-wall separation of the DWCNTs. Our density functional theory calculations reveal that the armchair-armchair systems are significantly more stable than both the corresponding armchair-chiral configurations, as well as the corresponding stacked graphene sheets. The results obtained for translational and rotational motion (slide / roll) of the CNTs indicate a potential use of DWCNTs as springs, ratchet wheels, nanogears and bearings in miniaturized devices. Our work enables us to predict the behavior of DWCNTs of different dimensions and would be of practical importance in the actual construction of nanoscale mechanical parts.

In this article, the doped zinc-ferrite nanoparticles with bismuth by using glycine as a fuel have been made by using the microwave combustion method. After synthesizing the ZnFe_2−xBi_xO₄ samples with x = 0.0, 0.02, 0.04, 0.06, 0.1, 0.15, dielectric properties such as dielectric constant, dielectric loss factor, and also conductivity $({\sigma }_{ac})$ were measured by using a LCR meter in the frequency range of 0–10 MHz. The results showed that the dielectric constant decreases with increasing the frequency; then its value reaches a constant magnitude. Also we considered the structural, morphological and magnetic properties of nanoparticles by using the x-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM), respectively. The optical properties of the sample were studied by using the visible-ultraviolet light (UV–vis) spectroscopy. The results of the XRD patterns showed no additional peak was observed in the samples, and this revealed that the samples are single-phase. Also these results showed that the lattice parameter increases with increasing the bismuth concentration. SEM results showed an ascending trend in the size of the nanoparticles. Also, considering the VSM results characterized that increasing the bismuth amount leads to lower saturation magnetization, coercivity and remaining magnetization of the samples. The results of UV–vis spectroscopy showed that increasing bismuth amount can increase the sample optical band gap.

To remove and recycle oil spills in a low-cost and facile way, we induced ethyltrichlorosilane to assemble into polysiloxane nanotubes by method of plasma enhanced chemical vapor deposition on surface of porous structure of melamine sponge. Obtained melamine sponge showed obvious hydrophobicity. polysiloxane nanotubes were successfully chemical bonded with melamine sponge as fourier transform infrared spectroscopy (FTIR) confirmed. Test of static contact angle (SCA) revealed the surperhydrophobicity of modified melamine sponge. Operation of oil/water separation showed its excellent properties of removing oil spills. Scanning electron microscopy (SEM) images showed the surface roughness increased obviously because of the mass-distributed polysiloxane nanotubes. Energy dispersive spectroscopy (EDS) characterized the variation of chemical element composition, which indicated the successfully grafting of polysiloxane nanotubes. Therefore, we applied a facile and efficient method to realize the experiment.

The production of the vertically aligned MoS₂ nanosheets has been generating an enormous interest due to their potential applications in the diverse research fields. However, the production methods for such vertical nanosheets, especially via chemical vapor deposition (CVD) route, used so far have involved complex- or multi-growth processing steps. To meet this demanding challenge, in this work we report high quality vertically aligned MoS₂ nanosheets grown by CVD in a single growth step, with reduced complexity of the growth processing steps. For the first time, we also studied the effect of substrate angle (ranging from 0° to 90°) during the growth on surface morphology, structural, and Raman spectroscopy properties of the as-grown MoS₂ vertical nanosheets. The results demonstrated that high quality vertically aligned nanosheets with packed density can possibly be achieved at 90° substrate angle. The characterizations such as XRD, HR-TEM and SAED patterns confirm the vertical orientation while SEM images reveal the excellent surface morphology and packed density of the MoS₂ vertical nanosheets. Additionally, Raman spectroscopy studies further evident of the verticality nature of the high quality nanosheets while XPS data confirmed that the as-grown material is of MoS₂. The relevance of the work is discussed in the context of the present fabrication methods for such vertically aligned MoS₂ nanosheets and also suggested their domains of applications.

Presence of both Cd(II) and Pb(II) ions in water is highly toxic for human health. That is why WHO recommends maximum permissible values of cadmium and lead in drinking water as 0.003 mg.L⁻¹ and 0.01 mg.L⁻¹, respectively. Therefore, here we report for the first time the adsorption kinetics of Mg(OH)₂ for adsorptions of Pb(II) and Cd(II). To the best of our knowledge, this is the very first attempt to evaluate the Langmuir and Freundlich isotherms of Mg(OH)₂ nanostructures with different morphologies for adsorptions of Pb(II) and Cd(II). The changes in adsorption processes with temperature are also studied. The Mg(OH)₂ nanostructures reduce the concentration of Cd(II) ions from as high as 1000 mg.L⁻¹ to as low as 0.001 mg.L⁻¹ and that of Pb(II) ions from as high as 1000 mg.L⁻¹ to as low as 0.009 mg.L⁻¹. These values are much lower than the permissible limits prescribed by WHO. To attain these very significant achievements the time dependent changes in pore size, pore size distribution and surface area are explored. Finally, the results obtained by XRD, FTIR, Raman, pore size, pore size distribution, BET surface area, FESEM, TEM, EDX and adsoption kinetics studies show that nanoplatelet Mg(OH)₂ powders exhibit the highest respective adsorption efficacies of 3700 mg.g⁻¹ and 3030 mg.g⁻¹ for Pb(II) and Cd(II). Thus, the nanoplatelet Mg(OH)₂ powders may possibly find huge usage in near future for water purification applications.

Silica-coated carbon nanotube has been synthesized through a variety of experimental techniques. In this work, we present results of a route of synthesis for multiwalled carbon nanotubes (MWCNTs)/Silica composites and Silica. This technique involves a reaction of carbon nanotubes dispersed using Gum Arabic with tetraethylorthosilicate (TEOS), Si (OC₂H₅)₄ in solution of ethanol, with NH₄OH as catalyst. Characterization of x-ray diffraction, infrared spectroscopy and scanning/transmission electronic microscopy confirmed the MWCNTs/Silica composite synthesis. In this methodology, acids were not used for functionalizing the surface of the carbon nanotubes. We also studied the composite thermal stability. The results of this paper suggest that our methodology can be used to develop less expensive electronic devices such as sensors, biosensors, capacitors, etc. Additionally, our methodology is easy to operate.

Dopamine was polymerized and decorated on surface of the hexagonal boron nitride (h-BN) to enhance the dispersibility and reactivity of h-BN. The polydopamine-decorated BN nanosheets were identified by Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. BN-based nanocomposites were prepared by curing reaction of epoxy E44, Jeffamine D-230 and polydopamine-decorated BN nanosheets. The thermal, mechanical and wear-resistant performance for nanocomposites with different BN loadings (0.5%, 1%, 2%, 4%) were characterized via thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and tribological tests. Results of thermal analysis showed that all BN-based composites possessed the superior thermal stability compared with the pure epoxy resin. The preferable mechanical and wear resistant performance of composites were attributed to the complementary role of mechanical, lubrication and thermal conductivity of BN nanosheets.

In this study, the different compositions of Zn–Cu–In–S quantum dots (ZCIS QDs) were prepared by a facile synthetic approach. The compositions and particle sizes of ZCIS nanocrystals were precisely controlled. The composition-dependent molar extinction coefficient of nonstoichiometric ZCIS QDs has been determined by combination of ICP-MS with UV–vis absorption and TEM. The molar extinction coefficient values were found to comply with a power function with exponents of 3.6 and 1.8 with the variation of the content of Cu or Zn, respectively. The extinction coefficient of ZCIS QDs exhibited the composition dependency and seemed to be larger than that of CuInS₂ for a given size. The determination of the extinction coefficient makes it feasible to calculate the concentration of ZCIS QDs in solution and promotes its further applications in bioanalysis.

This article is intended to analyze forced vibrations of a piezoelectric-piezomagnetic ceramic nanoplate by a new refined shear deformation plate theory in conjunction with higher-order nonlocal strain gradient theory. As both stress nonlocality and strain gradient size-dependent effects are taken into account using the higher-order nonlocal strain gradient theory, the governing equations of the composite nanoplate are formulated. When the nanoplate is subjected to a transverse harmonic loading and all the edges are considered as simple boundaries, the governing equations can be solved with a closed-form solution, from which the maximum dynamic deflections are obtained. To validate the results of the new proposed plate theory, the comparisons between ours and the well-known papers in the literature are presented. The influences of different nonlocal parameters and material properties on the nanoplate's dynamic responses are also studied.

Here we report an low-cost method for fabricating 3D hierarchical TiO₂ films with lotus-leaf-like micro/nano structures. With some low pressure provided by two middle-sized binder clips, the microscale pillar arrays of lotus leaf could be easily imprinted into the TiO₂ sol film. In addition, if a low vacuum was introduced into the imprinting process, the complex laminar sub-microstructure on the micro pillars could also be duplicated with high fidelity. Hierarchical TiO₂ micro/nano-structures were subsequently fabricated by the hydrothermal growth of TiO₂ nanorods on the micro-structured TiO₂ film. SEM observation and XRD analysis revealed that the micro-structured TiO₂ film was anatase phase, which served as a nucleation layer for the growth of rutile TiO₂ nanorods. This hierarchical surface exhibited a WCA of 155° after surface fluoroalkylsilane modification.

NiO/CuO/ZnO combined semiconductor metal oxide structures based ternary nanocomposites were synthesized in 2:1:1, 1:2:1 and 1:1:2 molar ratios using a simple and combined co-precipitation - hydrothermal method without utilizing any fuels, capping agents or surfactants. The structural, bonding, band gaps and morphological behaviour of the synthesized ternary nanocomposites were investigated using x-ray diffraction, Fourier transform infrared spectroscopy, UV-Diffuse reflectance spectroscopy and atomic force microscopic measurements. The dielectric properties recorded for these combined semiconductor metal oxide structures are valid with Maxwell-Wagner (M-W) model which is based on the dielectric nature in conducting grains layered with poorly conducting grain boundaries. The higher values of dielectric constant were observed for the ternary nanocomposite ratio 1:2:1 and the reduction in the values of dielectric constant of other ternary nanocomposite ratios (1:1:2 and 2:1:1) at lower frequencies is due to the fact the grain boundaries are preferably occupied by more Cu²⁺ ions than Ni²⁺ and Zn²⁺ ions. This kind of attempt in investigating the physical insights of combined semiconductor metal oxide structures is needed for the development of novel semiconducting devices.

A kind of novel D-A-A' type organic small molecule TPA(BT-CNC8)₂ based on triphenylamine was designed and synthesized, in which triphenylamine (TPA) was used as central donor (D) core, benzothiadiazole (BT) and i-octyl 2-cyanoacetate (CNC8) were used as main acceptor (A) and secondary acceptor (A') units, respectively. Its optical physical properties, thermal stability and electrochemical properties were tested and systematically investigated via ultraviolet absorption spectra, thermal gravimetric analysis and cyclic voltammetry measurement, respectively. TPA(BT-CNC8)₂ presented a wide absorption profile of 300–750 nm with an optical band gap of 1.65 eV. The highest occupied molecular orbital (HOMO) energy level of TPA(BT-CNC8)₂ was calculated to −5.40 eV, which was mainly originated from the strong electron-withdrawing effect of benzothiadiazole and i-octyl 2-cyanoacetate units. The bulk-heterojunction organic solar cells of TPA(BT-CNC8)₂-based was fabricated, in which TPA(BT-CNC8)₂ was used as donor material while PC₇₁BM as acceptor material, in the absence of optimizing device structure, its power conversion efficiency (PCE) reached to 1.62% together with a short circuit current density (J_sc) of 6.94 mA cm⁻² and open circuit voltage (V_oc) of 0.81 V. Further improvements of the device efficiency by optimizing the devices structure, using solvent additive or thermal annealing are currently under investigation.

Quaternary chalcogenide glasses based on sulphur and selenium Se₈₀S₁₈Tl_2-xYb_x (x = 0, 0.1, 0.2, 0.5 and 1) and Se₆₅S₁₀Ge_15+xIn_10-x (x = 0 and 5) were synthesized using the melt-quench technique. Formation of quaternary chalcogenide glasses was confirmed by Powder x-ray diffraction studies. Our differential scanning calorimetric studies on these glasses also are in good agreement with powder x-ray diffraction results. Thermo Gravimetric studies reveal the good thermal stability of these glasses. The IR transparency of Se₈₀S₁₈Tl_1.5Yb_0.5 extends throughout the range 3–25 μm and thus are good candidates for Infrared transmission applications.

In this article, the effects of sintering on the mechanical and electrical properties of ceramic porcelain insulator reinforced by zirconia (ZrO₂) particles are studied for the low frequencies (20 Hz–1 MHz). The samples were prepared for varying contents of zirconia by replacing alumina content in the base porcelain composition. The samples are sintered at 1250 °C and 1350 °C with a heating rate of 5 °C min⁻¹ and the soaking period is 2 h. The β-cristobalite phase of base porcelain decreases and the crystalline phase of zircon increases with the increasing sintering temperature. This improvement in crystallite phase of zircon improves the mechanical strength of the reported samples. The sample with zirconia content of 20 wt% sintered at 1350 °C shows the best mechanical properties with minimum water absorption of 0.89%. The highest measured value for modulus of rupture (MOR), compressive strength, and linear shrinkage are 138 ± 5 MPa, 221 ± 10 MPa, and 10.6%, respectively. The sample with zirconia content of 30 wt% sintered at 1350 °C shows the best electrical properties among all samples. Maximum observed value for AC dielectric strength of the sintered sample is 22.85 ± 0.5 KV mm⁻¹. The measured AC conductivities of samples are 3.88 × 10⁻¹² S cm⁻¹ and 1.41 × 10⁻⁹ S cm⁻¹ at 500 Hz and 1 MHz respectively. The complex permittivity's of the sintered samples are found to be dependent on contents of ZrO₂ and also exhibit a frequency dependent characteristics for a range of frequency (20 Hz to 1 MHz). The result indicates that variation in ZrO₂ composition leads to significant improvements in mechanical and electrical properties of porcelain ceramic.

Solid polymer electrolytes are widely used in several applications such as super capacitors, fuel cells, energy storage devices and sensors due to their excellent physical and chemical properties. The objective of the present investigation is to prepare solid polymer electrolyte films using PVP with different wt% ratios of CH₃COOK by solution cast technique and subsequently characterized by structural studies and electrochemical properties. XRD pattern showed a broad peak at 24.5° ascribed to pure PVP which indicates its semicrystalline phase. The little agglomerations observed in SEM images are due to the dispersion of salt embedded in the polymer matrix. The peaks observed in FTIR spectra for pure PVP at 944.5, 1105.6 and 1569.2 cm⁻¹ correspond to C–O bending, C–O stretching and C=O vibrations respectively. The peaks in Raman spectra observed at 760.5 and 451.3 cm⁻¹ relate to the C–H stretching, the peaks at 1378.31 and 1054.3 cm⁻¹ correspond to the C–H₂ bending and the peaks at 1423.8 and 1688.3 cm⁻¹ correspond to the CH₂ wagging for mixed salt-polymer films respectively. The ionic conductivity was found to be maximum (2.12 × 10⁻⁵ S cm⁻¹) for 80:20 wt% composition at room temperature. From electrochemical properties, it is observed that the voltage across the cell has been raised from 2.3 to 5.1 V. The performance of the cell capacity has been raised up to 1.2 h and becomes constant after certain time till 6.2 h. The storage aspect of the energy related issues is addressed by ion conducting polymer electrolytes and their applications in the field of rechargeable batteries.

Polybenzoxazine/epoxy-fumed silica filled composites have been prepared by blending benzoxazine with epoxy (EP) in presence of fumed silica (FS). It has been observed that the thermal stability of the composites increased with increasing amount of fumed silica in the composite composition. Mechanical properties of the composites have been investigated by using tensile and flexural tests. Composites consist of 4 wt% fumed silica in the polymeric matrices, exhibited higher tensile and flexural strength than neat polybenzoxazine, epoxy and their polymeric metrics blend. Prepared composites possess better mechanical and thermal properties than the neat polymers, as well as easy processibilty which can make them good candidates to prepare of complex reinforced structures for various industrial applications.

At the present time plastic majorly pollutes the environment. Lot of researchers are interested to minimize the environmental pollution by means of minimize or avoid plastic goods. Accordingly composite material is introduced and it is used instead of plastics goods like chairs, tables etc. The coir fibers are immersed in alkali solution due to increase the surface roughness of the coir fibers. The coir fibers are treated in different concentration of potassium hydroxide (KOH) with the various conditions of soaking period. Hand layup process is used to fabricate the composite. Then the mechanical properties are evaluated as per the standards of ASTM. The effect of KOH concentration and soaking time are deliberated based on evaluated values of mechanical properties to find out the optimum parameters of the composites.

In the present investigation, we have successfully fabricated and characterized modified Poly(methyl methacrylate) (PMMA)/Cellulose acetate (CA) nano blends as a function of graphene oxide (GO) loading. These nano blends were systematically characterized using x-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), FT-Raman spectra, Ultraviolet and visible spectroscopic technique (UV–vis), Thermogravimetric analysis (TGA). The weak interfacial interaction between the polymer blend system and GO influenced on the mechanical stress-strain behavior of the polymer blend. Scanning electron microscopic (SEM) study reveals the entanglement of polymer network and existence of occupied GO network. Topographic two (2D) and three (3D)dimension micrographs recorded by Atomic force microscopy (AFM) technique estimate the decreased surface roughness due to the presence of carbon. Dielectric performances were carried out using impedance analyzer as a function of frequency (10 Hz to 1 MHz) and temperature (30°C–150 °C). The dielectric constant for the pure blend (ε' = 2.25) was appreciably improved to three fold (ε' = to 2.25 × 10³) for 2 wt% GO loaded polymer blend system. The modified nano blends may be suitable for various electronic and electrical device applications.

Silk-based microsphere received remarkable attentions due to its impressive biocompatibility and biodegradation in drug delivery system. However, its application was still limited by complex process and unfriendly chemical agents using. In this study, we developed a novel approach to prepare silk fibroin nano or microspheres rapidly via electrostatic assembly. We demonstrated experimentally that the silk fibroin microsphere (SFM) with diameters ranging from 0.5 μm to 3 μm could be easily fabricated by combining pH value adjustment and low voltage electrostatic field. The production was optimized to be a simple and highly repeatable process that did not require sophisticated equipment and chemical agents. SFM represented α-helix structure enriching and homogeneous morphology, as well as improved dispersion and controllable size by regulating the silk fibroin concentration. The SFM demonstrated concentration-dependent drug release behavior with about 75% accumulative release ratio at day5. Thus, this SFM with high production efficiency and promise features provided a new drug carrier and substitute in control release field.

This paper reports experimental details for preparation of poly-dispersed hematite (Fe₂O₃) nanoparticles using Nyctanthes arbor tristis flower extract at physiological pH and room temperature. The bio-inspired fabricated iron oxide nanomaterial is characterized by XRD patterns which reveal the formation of a high crystalline quality with rhombohedral structure having hematite phase. It is observed that XRD peak intensity is affected by the concentration of precursor. The FT-IR analysis reveals the existence of Fe-O bonding in the synthesized nanoparticles. The FE-SEM analysis reveals the nanostructure which is found to be poly-dispersed bead like agglomerates. The synthesized nanoparticles exhibit potential antimicrobial efficacies against Kleb. pneumoniae and Staph. aureus. Also the minimum inhibitory concentrations of the synthesized nanoparticles have been determined.

Immobilization of enzymes on magnetic nanoparticles (MNPs) could offer reusability along with increased stability and robust operation at different physicochemical conditions. In this work, magnetically recoverable nano-biocatalyst was prepared by immobilizing industrially important α-amylase on chitosan coated Fe₃O₄ MNPs (AMNPs) and evaluated for its activity and stability. MNPs were characterized by x-ray diffraction, field emission scanning electron microscope and vibrating sample magnetometer. Functional groups on MNPs and chitosan coated MNPs along with immobilization of α-amylase on chitosan coated MNPs were analyzed by Fourier transform infrared spectroscopy. Amount of immobilized α-amylase was optimized by varying enzyme concentration and incubation time during immobilization process. The activity and stability of the AMNPs and free α-amylase were investigated. It was found that AMNPs have better starch digestion capacity at different physicochemical conditions than that of free α-amylase. The immobilized enzyme retained 66% activity after 20 days compared to 18% activity of the free enzyme. AMNPs were reused for 20 times, without significant loss of activity, by magnetically separating the nano-biocatalyst from the reaction mixture after each starch hydrolysis cycle.

ZrO₂ particles with an average diameter approximately 2 μm was prepared by hydrothermal reaction and functionalized in organic solvents using a di-functional surface modification agent, 3-methacrylopropyltrimethoxysilane (MPS). Surface-functionalized ZrO₂ particles were investigated by fourier transform infrared spectroscopy, thermogravimetric analysis and x-ray photoelectron spectroscopy. Furthermore, fabrication of poly (methyl methacrylate), PMMA, bone cement was conducted with MPS-functionalized ZrO₂ particles as an inorganic filler. ZrO₂ particles with surface vinyl groups exhibited good dispersion in the fabricated bone cement, leading to an improved bending strength of the bone cement products. The MPS-functionalized ZrO₂ particles, as a kind of filler, may be a potential candidate for the PMMA bone cement.

Substitutional doping of lithium also known as overlithiation, is one of methods widely used to improve performance of cathode material in Li-ion batteries. It is found that all prepared overlithiated samples, that is, Li[Li_xNi_0.7−xCo_0.2Fe_0.1]O₂ where x = 0.05, 0.1 and 0.15, show improved performance in terms of both specific capacities and cycling. The best of the materials exhibits an 18% increase in the first cycle and only an 8% capacity fading at the 50th cycle. Although this phenomenon of improved electrochemical characteristics is known, the scientific reasoning behind it is not that well understood. In this work, analyzing the materials from the aspects of crystal structure, crystallite size and oxidation states help contribute in the understanding of the fundamental causes of the improvement of the electrochemical behaviour of the overlithiated cathode materials.

In situ synthesized carbon quantum dot (CQD)-titanium dioxide (TiO₂) nanostructures were found to exhibit excellent photocatalytic dye degradation properties. CQDs were synthesized by solvothermal decomposition of PEG in basic pH in presence of NaOH and their morphology and photophysical properties were studied. Nanostructures were produced by synthesizing CQDs in the presence of (a) commercial TiO₂ [CQD/TiO₂-P25] and (b) TiO₂ precursor [CQD/TiO₂] to obtain co-synthesized nanostructures. The photocatalytic properties of the hetero-structures, was also studied and compared with those of commercial TiO₂-P25 and synthesized TiO₂. The photocatalytic degradation rates of methylene blue were found to rise in the order of TiO₂-P25 (2.00 × 10⁻³ min⁻¹), synthesized TiO₂ (6.7 × 10⁻³ min⁻¹), CQD/TiO₂-P25 (1.31 × 10⁻² min⁻¹) and CQD/TiO₂ (3.6 × 10⁻² min⁻¹) respectively. The highest degradation rate for CQD/TiO₂ among the samples is attributed to the superior interface between the CQDs and the TiO₂, leading to higher interfacial charge transfer. The observed 18-fold increase in degradation rate for CQD/TiO₂ over commercial TiO₂-P25 photocatalyst and the over two-fold increase over CQD/TiO₂-P25 photocatalyst, has significant techno-commercial implications, making CQD/TiO₂ a promising photocatalyst.

Hierarchical barium titanate (BaTiO₃) micro flowers have been successfully grown on the conducting glass substrates by a two-step hydrothermal process. Morphological and crystal structure analyses revealed that the tetragonal phase BaTiO₃ micro flowers have formed as clusters of highly crystalline, one dimensional parallelepiped nanorods of widths ranging from 50 to 500 nm. The as-grown BaTiO₃ micro flowers tested as dye sensitized solar cell (DSSC) photoanode has showed maximum power conversion efficiency (PCE) of 5.13%, which is comparable to the PCE of TiO₂ nanoparticles based DSSC photoanode (5.90%) measured under one sun illumination conditions. Besides, incident photon to current conversion efficiency (IPCE) and UV–visible absorption analyses have confirmed that the superior light-harvesting capability of BaTiO₃ micro flowers over TiO₂ nanoparticles is observed in DSSC due to their favorable morphological features and increased visible light absorption properties along with the superior charge transport characteristics of nanorods.

A silicon heterojunction solar cell constructed with sub-stoichiometric molybdenum oxide (MoO_x) carrier-selective layer and crystalline silicon substrate, which possesses a potential to achieve high power conversion efficiency, is investigated by numerical simulation tool AFORS-HET. In this work, MoO_x is chosen as the emitter layer of the silicon heterojunction solar cell to mitigate parasitic light absorption losses. The influences of MoO_x and p-a-Si:H layers with different thicknesses on the performances of the heterojunction solar cells are compared. The surface effect passivation is then used to explain the behavior of open circuit voltage increased with thickness variation, which physical mechanism is characterized by introducing the built-in electric field and minority carrier lifetime. Furthermore, we use the carrier recombination rate, band offset, and built-in electric field to investigate the effect of defect density states in the MoO_x hole selective layer. In this paper, the highest power conversion efficiency of 27.27% is obtained by optimizing the thickness and defect density states of MoO_x layer.

To explore the effects of nonmetal elements mono-doping, the electronic structures of (B, C, P, F) doped InNbO₄ have been investigated systematically based on the first-principles calculations. The obtained results revealed that the band edges of (B, C, P) doped InNbO₄ slightly expanded while the band gap of F doped InNbO₄ barely changed. Meanwhile, different p orbital states were introduced into the band gaps of InNbO₄ after (B, C, P) doping, which was in favor of extending the absorption spectra to the visible-light region. Among these nonmetal doping systems, it was noted that the band edge potentials of InNbO₄ satisfied the requirement for water splitting in C doped InNbO₄. The localized C 2p states could perform as intermediate levels to reduce the transition energy of photo-induced electrons. Therefore, we put forward that C atom should be a suitable dopant for single anion doping InNbO₄, which will provide a guideline for developing doping InNbO₄ with visible-light sensitive reactions.

The texturing of silicon surfaces is a well-known method of reducing the reflection from the surface of crystalline Si solar cell devices. With the utilization of diamond wires in recent advances in wafer slicing technology, surface texturing for the multi-crystalline Si wafers by the traditional acid-based texturing technique has become difficult. Metal-Assisted Etching (MAE) has been shown to be a promising and low-cost alternative to the traditional acid-based isotropic texturing. This paper reports, for the first time, a new single-step Ni-assisted etching technique to obtain nano-scale porous structures, that is, black silicon on multi-crystalline wafers. We observed lower reflection results in comparison with standard isotropic texturing using a standard acid solution. The structural and optical properties of the surface were identified through reflection measurements and scanning electron microscopy imaging. As a final step, the optimized texturing process was applied to multi-crystalline solar cell devices and showed promising results regarding cell performance parameters.

The characteristics of Durio Zibethinus seed starch (DSS) that is used for landfill leachate treatment was investigated in this study. The DSS was extracted using dry milling (DM-DSS) and wet milling (WM-DSS) methods. The physico-chemical properties and surface morphology of the extracted starches were examined and analysed. Besides that, the efficiency of the extracted starch to remove colour, COD, suspended solid and turbidity were also evaluated and compared. Based on the results obtained, the WM-DSS showed better starch characteristics with high purity and smooth granule particles compared to DM-DSS. In addition, WM-DSS also recorded better leachate contaminants removal even at low dosage. Nevertheless, the performance of leachate contaminants removal for both extracted starch was very low. Thus, further chemical modification is required in order to improve the coagulation ability of the extracted starch. This finding indicated the potential of WM-DSS to be use as a coagulant aid for landfill leachate treatment.

Carbides present high capacity due to their excellent conductivity as well as fast redox reactions with protons on the surface. Molybdenum carbide (Mo₂C), a typical carbide, has been synthesized successfully by calcining amine metal oxide. Served as electrodes for supercapacitors, the energy density is poor due to the narrow operating potential window in aqueous electrolyte (ca. 1.2 V). Whereas proton ionic liquids, a class of novel electrolyte, can expand the operating potential window as well as provide protons for electrochemical reactions, therefore guaranteeing a high energy density and capacitance. 1-ethyl-3-methylimidazolium acetate/acetonitrile (EMIMAc) is a new type proton ionic liquid for supercapacitors. For the Mo₂C electrode, the high specific capacitance of 88 F g⁻¹ was achieved in 2 mol L⁻¹ EMIMAc/AN electrolyte at a current density of 0.5 A g⁻¹. The Mo₂C//AC asymmetric capacitor with an operating voltage of 2.5 V retains 95% of the initial specific capacitance after 1200 cycles and exhibits a high energy density of 44.1 W h kg⁻¹. The prominent capacitive performance could be attributed to rapid electron transfer and highly exposed active sites of Mo₂C nanoflakes. Besides, 1-ethyl-3-methylimidazolium acetate ionic liquid provides wider electrochemical window to ensure large output. The use of EMIMAc/AN electrolyte dramatically improve the energy density of the asymmetric supercapacitors and can be applied to other carbides.

Micro-energy harvesting has gained immense interest among the research community due to the requirement for self-powering of sensor units in unapproachable environments. Use of simple, low cost, flexible energy harvester aids generation of energy from ambient environments. The present work proposes two devices under test(DUT) with different electrodes namely copper(DUT1) and carbon fibre(DUT2), polymers Polyvinylidene fluoride (PVDF), Polydimethylsiloxane (PDMS) as a functional charge generating materials. The piezoelectric and triboelectric characterisation of polymer films is performed using Dynamic contact mode electrostatic force microscopy(DC-EFM). The proposed DUT1 and DUT2 generates an 8 Vpp and 9 Vpp during human finger tapping. The qualitative and quantitative analysis of DUT1 and DUT2 generated an output voltage of (8.5 V, 12.35 V) (high pressure),(13.5 V, 14.1 V) (285 rpm) respectively. The carbon fibre electrode based flexible device generated an output voltage of 9 V, 10 V and 2.275 V when subjected to biomechanical operations such as finger assisted tapping, press and release as well as bending operations. The device with copper electrode generated 0.32 nJ of energy and power density per unit area of 2.37 pW cm⁻² in a single tap cycle. The DUT2 generated thrice the energy and power density than that of DUT1. The DUT2 thus promises to be an efficient, low-cost, flexible energy harvester with PVDF as well as PDMS polymers as a functional layer.

Present investigation deal with the facile synthesis of Co₉Se₈ nanoparticles (NPs) and their application as the potential anode for lithium-ion battery (LIB). The primary size of the Co₉Se₈ NPs can be achieved between 10 ∼ 25 nm while the secondary cluster size ranging from 150 ∼ 200 nm as observed by transmission electron microscope (TEM). The specific capacity of Co₉Se₈ NPs LIB anode can reach around ∼610 mAhg⁻¹ during charging (lithium ion released from Co₉Se₈ nanoparticles), and ∼730 mAhg⁻¹ during discharging (lithium ion intercalated) at an applied current density of ∼100 mAg⁻¹. These values are significantly higher than that of the commercial graphite anode (theoretical capacity ∼372 mAhg⁻¹). The irreversibility of Co₉Se₈ anode (∼15%) is also significantly lower than that of most metal oxides and silicon-based anodes (irreversibility ranging between 30 ∼ 50% or higher for Si). The reason for superior specific capacity and low irreversibility compared to metal oxides and silicon-based materials could be owing to the stable nano-cluster size which help to reduce the diffusion path and internal resistance to lithium ion.

A new molten salt method is designed to synthesize spinel LiNi_0.5Mn_1.5O₄ cathode material, and the reaction medium NaCl is in situ formed in the process of precursor preparation via room temperature solid-state reactions. Pure LiNi_0.5Mn_1.5O₄ can be successfully synthesized at 950 °C in an open alumina crucible in air and a further rise in heating temperature leads to the appearance of a small amount of impurity. Electrochemical test shows that the LiNi_0.5Mn_1.5O₄ obtained at 1000 °C has the best electrochemical performance and can deliver a high capacity of 134 mAh g⁻¹ with excellent cycling stability.

We investigated the improvements in the photocatalytic properties of Bi₄O₅Br₂ after Mn-doping via first principles calculations. Based on the formation energy calculation, transition metals replaced Bi atoms with a coordination bond of 4. Importantly, the Mn-doped Bi₄O₅Br₂ has the lowest band gap among transition metal-doped Bi₄O₅Br₂. The key factors underlying the improvements in photocatalytic efficiency are estimated as follows. First, the band gap decreased from 2.38 eV in the pristine case to 1.88 eV in the six Mn-doped Bi₄O₅Br₂ case resulting in a shift of the photon absorption edge to lower energy. Second, the absorption coefficient in the visible light range obviously increases with Mn-doped Bi₄O₅Br₂. Third, the relative mass ratio of photoinduced electrons and holes increases with Mn concentration resulting in a higher efficiency of charge carrier separation. Therefore, it is reasonable to believe that the photocatalytic efficiency of Bi₄O₅Br₂ can be improved via Mn-doping. Our work provides a reasonable rationale for choosing Mn as a dopant—this can help experimental work and explain the improvements in photocatalytic efficiency.

The performance of the direct formic acid fuel cell largely depends on the quality of the electrocatalysts used in the fuel cells. New materials are of great interest in order to improve the activity and stability of the electrocatalyst used in formic acid electro-oxidation for better direct formic acid fuel cell performance. In this study, different support materials including synthesized graphene aerogel (GA), commercial carbon black (C) or their hybrids(GA/C) were used. Platinum (Pt) nanoparticles were decorated on the defect sites of these materials by using microwave irradiation in order to improve the catalytic activity for formic acid electro-oxidation in acidic media. GA/C hybrid supports are synthesized via simple liquid mechanical mixing approach (GA/C(1)) and through hydrothermal process (GA/C(2)). Synthesized catalysts were called Pt/C, Pt/GA and Pt/GA/C(1) and Pt/GA/C(2). The as-prepared catalysts were characterized with SEM, TEM, XRD and ICP-MS. The SEM results show that GA has a 3D macroporous structure. Electrochemical measurements tests showed that either GA or GA/C material is promising support materials for Pt nanoparticles towards formic acid electro-oxidaiton. The electrochemical test results revealed that the support material affect the activity. Synthesized GA supported catalysts gave better activity than synthesized commercial carbon supported catalyst for oxidation of formic acid. Pt/GA and Pt/GA/C(2) catalysts showed higher tolerance against the poisoning effect of CO and direct pathway dominated the electro-oxidation of formic acid.

Herein, we have demonstrated the role of simple graphene oxide (GO) sheets as electrocatalyst for the voltammetric detection of nitrobenzene (NBz). GO was synthesized from natural graphite flakes and characterized by PXRD, FE-SEM, FTIR and UV–vis spectroscopy. A binder free electrochemical sensor by modifying active surface area of glassy carbon electrode (GO/GCE) was developed using simple drop casting method. The electrochemical behavior of the developed sensor towards NBz was examined extensively using cyclic voltammetry (CV), linear sweep voltammetry (LSV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The modified GO/GCE sensor showed a limit of detection (LOD) of 66 nM by CV, 79 nM by LSV,146 nM SWV and 135 nM and corresponding sensitivity of 157.14 μA μM⁻¹ cm⁻², 297.21 μA μM⁻¹ cm⁻², 677.14 μA μM⁻¹ cm⁻² and 1216.71 μA μM⁻¹ cm⁻² were observed by CV, LSV, DPV and SWV respectively.

Polystyrene has found wide variety of applications in mechanical and structural engineering fields, owing to its highly desirable physical properties. One of the key goals of researchers all over the globe is to improve the mechanical properties of polystyrene through reinforcement with nanoscale materials. The improvement in mechanical properties will in turn, increase the scope of utilization of polystyrene in many advanced mechanical applications. New generation carbon materials like carbon nanotubes and graphene have been proven to possess excellent mechanical properties and hence can serve as excellent nanoscale reinforcement materials for polymers. Present manuscript, demonstrates a facile method to use carbon nanotube/graphene mixture to improve mechanical properties of polystyrene. Thin films of the polystyrene-carbon nanotube/graphene hybrids were prepared and characterized by differential scanning calorimetry and nanoindentation techniques. The nanohybrid displayed considerable enhancement in midpoint of glass transition temperature (T_g). T_g of the hybrid nano-composite was improved significantly, compared to pristine polystyrene samples. Considerable improvement in modulus and hardness was also observed after reinforcement, which in turn, enhances the scope of application of polystyrene in advanced mechanical applications.

This study proposes the cantilever design of piezoelectric energy harvester scavenging energy from blood pressure variation in cardiac cycle. The harvester could be a perennial source of power for a typical pacemaker. The concept of three cm long and 72 μm thin cantilever based energy harvester having natural frequency close to that of heartbeat has been proposed. Considering a huge difference between shear (d₁₅) and transverse (d₃₁) piezoelectric coefficient the harvester was operated in two different modes. A number of materials (single and polycrystalline ceramics) along with Pb[Zr_xTi_1−x]O₃ (PZT-5A) were operated in transverse and shear modes. The maximum open circuit voltage found for all cases was ∼6 V which was yielded by Pb(Zn_1/3Nb_2/3)O₃–(6–7)% PbTiO₃ (PZN-PT) when operating in shear mode. Further, the optimum resistance was calculated for all the materials under study operating in d₁₅ and d₃₁ modes for a wide frequency range. It was found that the maximum power among all materials under study was given by PZN-PT which is ∼13 μW while operating in shear mode. Such high magnitude of power harvested is due to its giant d₁₅ which is 6000 pC N⁻¹ and is sufficient to power a typical pacemaker.

Since dielectric elastomer actuators are commonly used as artificial muscles, different approaches in material parameters identification have been used. Most dielectric actuators are parametrized with the help of continuum mechanics. Alternatively, rheological models can be used. Unfortunately, in basic rheological models, frequency dependence of viscoelastic materials cannot be obtained with a single equation. In order to obtain frequency dependences of viscoelastic material, fractional Kelvin-Voigt model is used. Fractional Kelvin-Voigt model can be applied for parameters identification in case of dynamical or cyclical excitation with different frequencies and for creep and stress relaxation analysis. Basic Kelvin-Voigt is limited on specific frequency and on creep. It cannot provide stress relaxation. Fractional Kelvin-Voigt model can further be used for fractional control. All previous work dealing with this subject is focused on analysis of material properties. Our contribution and novelty is in preparing governing equations for development control algorithms for dielectric elastomer actuators.

A novel functional ionic liquid (ILM) was synthesized using the ion exchange reaction of mercaptobenzothiazole (MBT) and 1-allyl-3-methylimidazolium. ILM was then added into carbon black/rubber, silica/rubber and microcrystalline cellulose (MCC)/rubber compounds, respectively, and its effects on the processing, physico-mechanical, and dynamic properties of the vulcanizates were investigated. For carbon black/rubber and silica/rubber compounds, ILM worked very well as a curing accelerator and surface modifier of carbon black and silica. For MCC/rubber compounds, the improvement was slight for the curing rate but obvious for the tensile properties. And it is noteworthy that the sizes of the MCC were decreased in situ from 20–90 μm to less than 5 μm during the processing of the rubber compounds, and the interfacial bonds between MCC and the rubber matrix were also improved. These results indicate that ILM is a multifunctional additive that can be used in different rubber composites.

Zinc oxide (ZnO) was synthesized by using continuous microwave (Mw) flow synthesis. The synthesized nanoparticles were characterized by x-ray diffraction and transmission electron microscopy techniques to study the phase composition, particle size and morphology. Transmission electron microscopy studies revealed an increase in the particle size from 6–12 nm upon increasing the reaction time. Photoluminescence (PL) studies were utilized to explore the surface defects and oxygen vacancies present in the ZnO. PL results confirmed a gradual decrease in the intensity of surface oxygen vacancies and defects of ZnO nanoparticles on increasing the dwell time inside the Mw. Similarly, energy bandgap studies showed a red shift in the energy bandgap from 3.19 eV to 2.91 eV with change in the reaction time. A red shift in energy bandgap is a good sign as it can enhance the utilization of ZnO nanoparticles in many of visible range applications such as optoelectronics and solar cells industry.

The electronic structure, energy band and density of states (DOS) were calculated from the density function theory (DFT) for pure SnO₂ and Ti doped SnO₂ of various concentrations. The results reveal that: the 3d electronic state of Ti atom has a great contribution to the conduction band at the Fermi level, as a result, the conduction band shifts to the lower energy level, the forbidden bandwidth is smaller and the electrical conductivity is improved than that of pure SnO₂. With the decreases of Ti doping concentration, the forbidden bandwidth decreases gradually, in other words, the electrical performance is gradually improved, and when the doping concentration of Ti is 6.25%, the forbidden bandwidth is at the lowest level, that is 0.148 eV. According to the semiconductor theory, the relative electron hole number and the electron hole effective mass of Ti doped system were calculated. The results show that with the decreases of Ti doping concentration, the relative electron hole number increases and the electron hole effective mass decreases. When the doping concentration of Ti is 6.25%, the hole effective mass is 0.242 m₀, the relative quantity of hole is 0.5355. At last, the experiment verification reveals that when the doping concentration of Ti is 6.25%, the experimental value of electric conductivity is the largest, that is 58.09%IACS. In summary, when the doping concentration of Ti is 6.25%, the SnO₂ material has better electrical properties. This research provides theory and data support for further study on AgSnO₂ contact materials.

We report on the high quality single crystal of Cr_xNbSe₂ growth to study the effect of Cr impurity on the vortex dynamics of NbSe₂ superconductor using M–H curves with different relaxation rates. The field dependence nature of critical current density (J_c) is well investigated using Larkin-Ovchinnikov collective pinning model and Anderson-Kim's plastic creep model. We have observed significant improvement in the field dependence nature of J_c with increasing Cr impurities in NbSe₂. This reveals the crossover of vortex lattice from elastic (E) to plastic (P) creep region causing second magnetization peak (SMP) or fishtail effect at highest Cr concentration, which has not been yet observed. Also addition of Cr impurity enhances the J_c up to 4 × 10⁵ A/cm². However, the interaction between core region of vortices and pinning centres ensure the δl pinning in Cr_0.0005NbSe₂ and significantly improved with increment of Cr impurity, which allowing both δl and δT_c mechanism. Both, δl and δT_c core pinning strongly enhance the coupling between vortices in pinning potential of nonstatistical distribution of Cr impurity, which makes 3D magnetic fluxes into 2D nature. Furthermore, the point pining and surface pinning mechanisms are responsible for pinning at low magnetic field region in Cr_0.0005NbSe₂. The appearance of prominent peak in pinning force density near upper critical field (H_c2) indicates the lattice softening at higher Cr impurity. These studies not only provide fundamental study of vortex dynamic but also open the door for further study in low T_c superconducting materials.

'Co-filled' and 'Fe-filled' multiwall carbon nanotubes (MWCNTs) were grown using microwave-plasma chemical vapour deposition (MPCVD) and thermal chemical vapour deposition (TCVD) methods respectively, and their structural and magnetic properties were studied for magnetic device applications. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show the average tube length ≈80–500 μm with outer (inner) diameter ≈20–50 (≈10–20) nm for MWCNTs prepared by both methods. The diffraction peaks of both x-ray diffraction patterns show the interlayer distance, d₀₀₂ ≈ 3.36 Å, which is comparable to the graphite structure (d₀₀₂ = 3.35 Å). The graphitic crystallite sizes (L_a) of MPCVD (TCVD) synthesized MWCNTs are ≈24.78 nm (≈22.13 nm) as obtained from the intensity ratio of (I_D/I_G) D-peak, the disordered structure of graphite and G-peak, the C−C bond in graphitic structure of Raman spectra. The magnetization of 'Fe-filled' TCVD grown MWCNTs is much higher than 'Co-filled' MPCVD grown MWCNTs due to the formation of higher content of Fe–C and/or Fe-oxides in the MWCNT structures. The higher magnetic coercivity ≈2900 Oe and formation of isolated single-domain Fe-nanoparticles in 'Fe-filled' TCVD grown MWCNTs, as found from SEM / TEM micrographs, makes the ferromagnetic MWCNTs a promising material for the high-density magnetic recording media.

The composites samples (1-x) (Cu₀.₆Zn₀.₄Fe₂O₄) CZF + x (BaTiO₃) BT, where (x = 0%, 10%, 20%, 30%, 40%, 50% 60%, 70%, 80%, 90% and 100%), have been prepared by ball milling. The x-ray diffraction showed that two phases have retained their identity in the composites and no undesired reaction has occurred between two phases. The tetragonality factor (TF) of ferrimagnetic phase increases with BT content up to x = 30% and then decreases at x = 40% but, for higher BT content; TF is nearly constant. The AC resistivity enhances with BT content, showing semiconductor behavior. Furthermore, it is demonstrated that CZF enhances ferroelectricity of BT. In addition, the initial permeability of the samples decreases with BT content and increases with higher selected frequency. It is demonstrated that the magnetoelectric voltage coefficient (ΔE/ΔH) depends strongly on BT content. The maximum ΔE/ΔH of some CZF-BT composites is higher than reported values of other ferrite-BT composites indicating vital role of CZF in developing magnetoelectric effect for ferrite-BT composites.

The paper presents the synthesis, characterization of Lanthanum substituted Barium ferrite material and its real time application in the development of miniaturised navigational antenna at 2.492 GHz. The Lanthanum substitution is observed to increase the ferro magnetic resonance frequency of BaFe₁₂O₁₉ parent material because of its octahedral site preference. Among the synthesized material, the BaLa_0.2Fe_11.8O₁₉ material has resulted in higher effective magnetic permeability of around 2.5 and dielectric permittivity of around 5.5. The Quadrifilar helix antenna which is miniaturised by loading the BaLa_0.2Fe_11.8O₁₉ material has the axial height reduction of 59% compared to the conventional quadrifilar helix antenna, while retaining the radiation characteristics like gain and band width.

Recombination zone (RZ) confinement and charge balance are the most important factors for realizing the enhanced efficiency in phosphorescent organic light emitting devices (Ph-OLEDs). Here, we demonstrated the RZ movement and improved Ph-OLED efficiency by varying the electron transport layer 2,2',2''-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) thickness. The thickness increment of TPBi not only control the electron transport on to the emission layer but also shifting the RZ towards cathode. The RZ movement in Ph-OLED with different thick TPBi is extracted from the exciplex peak generated at exciton blocking layer/emission layer (EML) interface. The optimized electron to hole ratio at EML have occurred with 40 nm TPBi in which the Ph-OLED exhibits superior current efficiency of 80 cd A⁻¹. The Ph-OLED efficiency roll-off is also very low in 40 nm TPBi based devices. This efficiency roll-off and RZ shift were simply estimated by interface exciplex peak in electroluminescence intensity without extra sensing layers. Further, the electron only devices made with various TPBi thickness also demonstrated the possible changes in the electron transport and supports the RZ and charge balance tactics.

Transmission of electromagnetic waves of millimeter waveband through two plates of yttrium iron garnet and reflection of waves from the plate are experimentally studied. It has been established that the coefficients of transmission and reflection undergo large variations when magnetic field is applied. The method of calculation of magnetic field dependencies of transmission and reflection coefficients is performed based on the ferromagnetic resonance linewidth alone.

Prediction of ionic-solid properties presents a great challenge to Kohn–Sham conventional density functional theory, due to the fact that there is strong van der Waals interaction between ion cores. In this work, we apply the Tao-Mo (TM) semilocal density functional to calculate lattice constants, bulk moduli, and cohesive energies for ionic solids consisting of alkali halides, silver halides, and other ionic solids. Our calculation shows that the TM functional yields accurate lattice constants, with a mean absolute error (MAE) of 0.087 Å, which is obviously smaller than commonly-used semilocal functionals such as the local spin-density approximation (LSDA) and Perdew–Burke–Ernzerhof generalized gradient approximation (PBE GGA). It is even more accurate than dispersion-corrected density functional PBE + D3 (MAE = 0.116 Å). This is unexpected success. For bulk moduli, TM functional can also yield very good accuracy, with an MAE of 3.02 GPA. Finally, we evaluate the cohesive energies of ionic solids. We find that this functional produces an MAE of 0.13 eV/atom, which is more accurate than the LSDA and PBE GGA, but less accurate than PBE + D3. We have also made a comparison of TM with other semilocal density functional theory (DFT) methods on several other ionic solids. It appears that TM also gives an overall improvement upon other popular semilocal DFT methods such as PBE for solids and Tao–Perdew–Staroverov–Scuseria.

The structural, electronic, mechanic, vibrational and thermodynamic properties of Ti₂SiB which is a hypothetical MAX phase compound, have been investigated using density functional theory calculations. The structural optimization of Ti₂SiB has been performed and the results have been compared with Ti₂SiC, Ti₂SiN, and Ti₂AlB that are studied in the literature. Then the band structure and corresponding partial density of states are computed. In addition, charge density and Bader charge analysis have been performed. The elastic constants have been obtained, then the secondary results such as bulk modulus, shear modulus, Young's modulus, Poisson's ratio, and Vickers Hardness of polycrystalline aggregates have been derived, and the relevant mechanical properties have been discussed. Moreover, the elastic anisotropy has been visualized in detail by plotting the directional dependence of compressibility, Poisson ratio, Young's and Shear moduli. Furthermore, the phonon dispersion curves as well as corresponding phonon PDOS, and thermodynamical properties such as free energy, entropy and heat capacity have been computed and the obtained results have been discussed in detail. This study provides the first considerations of Ti₂SiB that could have a potential application in nuclear industry.

Electrowetting has the potential to be applied to steering and concentrating sunlight using liquid lenses. However, the performance of electrowetting devices depends on the careful selection/fabrication of their constituent dielectric material. The dielectric material should have high optical transparency, chemical stability, high relative permittivity, be relatively thin and have a high breakdown voltage. Recent studies noted that inorganic dielectric materials such as SiO₂ are more suitable for beam steering compared to organic dielectric materials such as fluoropolymers or parylene C for example. When optical transmission is not required, electrowetting devices are fabricated by thermally growing SiO₂ on top of silicon wafers. However, this deposition method is not suitable for beam steering electrowetting devices as the silicon substrate is not optically transparent. In this paper, we investigated the performance of SiO₂ as a dielectric material for beam steering electrowetting devices. Specifically, we measured the contact angle modulation capability of SiO₂ produced by electron-beam and sputtering deposition methods and correlated the results with morphological defects of the SiO₂ layer introduced by the deposition methods. We investigated the effect of annealing and the performance with ionic and DI water. Finally, we compared the performance of SiO₂ with other dielectric materials such as PDMS and Ta₂O₅ in air/water and silicone oil/water medium.

Toward the processing of a multifunctional material, single crystals of PEA-CuCl₄ [PEA = (C₆H₅-C₂H₄-NH₃)₂] were obtained by slow evaporation technique. X-ray Diffraction powder, Scanning electron microscopy (SEM) and UV-Visible spectroscopy were used to characterize the purity, the morphology of the compound and the optical properties, respectively. PEA-CuCl₄ crystallizes in Orthorhombic system, C2cb (n^o 64) with a = 39.021(8) Å , b = 7.343 0(15) Å, c = 7.393 9(15) Å and Z = 8. The 3D and 2D Hirshfeld Surfaces analysis reveals the importance of hydrogen bonding in the stability of the bulk. The optical study shows that the compound undergoes an indirect optical transition with phonon assisted Cu²⁺ d-d transitions in the visible region, and presents an energy band gap of about Eg = 2.3 eV. In parallel, the electronic band structures, the electronic densities of states and the energy gap value (Eg = 1.99 eV) were calculated using DFT+U calculations. The calculated and experimental results are in good agreement.

As a two-dimensional (2D) electride, single-layer Ca₂N is vastly reactive because of its additional electron yet to be passivated. Selecting functionalization species that passivate single-layer Ca₂N is therefore critical for potential applications of this 2D electride at ambient conditions. Here we apply a high-throughput approach of density functional theory calculations to 33 elements across the periodic table for functionalizing single-layer Ca₂N. We compute the adsorption energy for each of these elements adsorped at three different high-symmetry sites of single-layer Ca₂N. The high reactivity of single-layer Ca₂N is reflected by significant adsorption energies for all of the considered species. We also find that the adsorption energy is determined by the interplay of the factors of geometry and electronic structure including the Pauling electronegativity and the Bader charge transfer. In particular, a strong, positive correlation exists between the adsorption energy and the interatomic distance between the adsorbate atom and its nearest-neighboring Ca atom. There is additionally a significant, negative correlation between the adsorption energy and the Pauling electronegativity. By contrast, the negative correlation is much weaker between the adsorption energy and the Bader charge transfer. Finally, we used the cases of oxygen and fluorine atoms adsorped on single-layer Ca₂N as two examples to demonstrate the importance of the three factors. Our work provides a general framework of selecting suitable elements for functionalizing single-layer electrides.

The significant impact of structural order on electrical properties of oxygen-deficient perovskites has been demonstrated through investigation of Sr₂Fe₂O₅ and Ba₂Fe₂O₅. The vacant sites created due to oxygen-deficiency are known to order differently in these two materials, leading to different structures. Sr₂Fe₂O₅ contains alternating layers of FeO₄ tetrahedra and FeO₆ octahedra, whereas Ba₂Fe₂O₅ comprises a complex array of FeO₄ tetrahedra, FeO₅ square-pyramids, and FeO₆ octahedra. Here, we show that these structural differences lead to notable variations in magnetic properties, where Ba₂Fe₂O₅ shows significantly higher magnetization compared to Sr₂Fe₂O₅ in the entire temperature range, 2–400 K. More importantly, the differences in structural order lead to drastic variations in electrical conductivity. The room temperature electrical conductivity of Sr₂Fe₂O₅ is about two orders of magnitude greater than that of Ba₂Fe₂O₅. Variable temperature conductivity measurements in a wide temperature range, 25 °C–900 °C, reveal even more interesting differences between the two compounds. The conductivity of Ba₂Fe₂O₅ remains nearly unchanged up to ∼400 °C, followed by a mild linear increase up to 900 °C. On the other hand, the conductivity of Sr₂Fe₂O₅ shows a sharp increase above 200 °C, which continues up to ∼700 °C, followed by a plateau, i.e. saturation region, in the range 700 °C–900 °C.

Silver nanoparticles thin films are used for effective light trapping of thin film silicon solar cells. In this work, we demonstrate the effect of the substrate temperature of silver nanoparticles thin film deposited upon a-Si:H/μc-Si:H thin film using Physical Vapor Deposition PVD technique, where a silver layer was deposited on a p-i-n junction on ITO glass substrate at different substrate temperatures. The morphology of the silver layer was studied by FESEM and atomic force microscope AFM and found to be consisting of nano-sized particles. The performance of a-Si:H/μc-Si:H thin film solar cell was evaluated by current-voltage measurements and optical absorption. It was observed that the silver nanoparticles size and surface roughness increase with increasing the substrate temperature, however the surface roughness increases only till TS = 200 °C and remains constant at 88 nm. The maximum efficiency was achieved (7.38%) for the substrate temperature of 200 °C. For this condition, the maximum absorption achieved was (74% at 300 nm) and (17% at 500–800 nm, respectively).

Nowadays, Ultraviolet (UV) curing adhesives have been extensively researched in the fields of health care and electronic components thanks to their high curing rate, low energy loss, no solvent pollution and excellent properties. UV curing systems bearing modified acrylate prepolymers have been widely utilized in the field of electric industry packaging. The advantages are low cost, high reliability, quick curing velocity, high mechanical trait and strong solvent endurance. For further optimizing the curing rate, curing volume shrinkage and thermal resistance of UV curing adhesives, in present work, two kinds of novel UV curable adhesives bearing epoxy and polyurethane modified acrylate prepolymers were designed and fabricated. Adhesive properties and thermal resistance of two adhesives were studied firstly. Boiling and solvent tolerances as well as bin stability of adhesives were discussed. Finally, over-all performances of as-prepared adhesive and purchased commercial adhesive were compared. High curing rate, low curing volume shrinkage and high heat resistance were achieved. This work might offer a facile and practical route to prepare the high-performance UV curable adhesives with significantly improved over-all properties by formula design.

In this letter, transparent Ni_xMg_1−xO film with good surface quality were obtained by advancing pulsed laser deposition method. The surface morphology and optical properties were investigated by changing the substrate temperature and laser energy density. It was found that the surface quality of Ni_xMg_1−xO can be improved greatly through the rising of substrate temperature or increasing laser energy density. In this case, the optimal deposition parameter was at 500 °C–5 J cm⁻². The annealing process was proved having remarkable impact on the surface topography. The optical band gaps which range from 3.88 eV to 4.16 eV were obtained through UV–vis absorption spectrum, as the deposition temperature increasing, the blue shift of absorption edge happened. The annealing was found to broaden the band gaps of samples deposited at lower energy density but have no effect on the band gaps of samples deposited at higher energy density. The abnormal width of band gaps were found, we speculate that the element uniformity of film plays an important role in band gap engineering.

ZnS thin films grown by the chemical bath deposition method have been under intense investigation due to their applications in solar cells. In this work, the early growth stages of ZnS thin films deposited by means of a non-toxic solution are studied by measuring the morphological, chemical and optical properties of the films obtained at different deposition time (5, 10, 20, 30, 60, 90 and 120 min). From the atomic force microscopy (AFM) studies, it was seen that the substrate surface is not fully covered before 20 min, and the growth exponential value changed from 0.5 to 1.8. The x-ray photoelectron spectroscopy (XPS) measurements revealed the presence of the Zn–O bond and the absence of the S–Zn bond at the earliest deposition time. Additionally, from XPS analysis, a shift in the signals for O1s and Zn2p_3/2 for the sample grown at 30 min was observed due to the formation of Zn(OH)₂. Finally, the UV-Vis spectrophotometry measurements showed that all samples have a high transmittance (>80%) and that the band gap value decreased as the deposition time increased.

The superior diamond-like carbon (DLC) films are of extremely significance, and three typical elements including hard metal, soft metal and rare earth co-doping could be a feasible way to achieve their promising properties. In this paper, the (Cu, Ce)/Ti co-doping strategy was employed to prepare (Cu, Ce)/Ti-DLC films via vacuum direct current reactive magnetron sputtering technology at different methane flow rate. The evolutions of microstructure, mechanical properties, tribological and anti-corrosion performances of as-prepared films were systematically investigated. Results revealed that as-prepared (Cu, Ce)/Ti-DLC films could exhibit typically nanocrystalline/amorphous characteristics, including TiC, Cu and Ce dispersed in the carbon matrix. As the flow rate of CH₄ increased, the carbon content of the films raised gradually while the content of Ti exhibited a reversely discipline, and the hardness and elastic modulus of the films presented an increased trend. Particularly, it possessed superior adhesive strength of 32.9 N, and exhibited the best tribological performances with low friction coefficient of 0.095 and wear rate of 2.53 × 10⁻⁷ mm³/Nm for the (Cu, Ce)/Ti-DLC film deposited at CH₄ flow rate of 7 sccm. Also, the film deposited at CH₄ flow rate of 7 sccm presented optimal corrosion resistant property with the lowest value of 1.474 × 10⁻⁸ A · cm⁻².

lead antimony sulfide (PbSb₂S₅) thin films were successfully grown on an n-Si substrate by a thermal evaporation technique. The XRD spectrum clarifies the orthorhombic structure of the prepared PbSb₂S₅ thin films and the EDX analysis specifies that its composition is near stoichiometric. In the dark conditions, I-V characteristics of the PbSb₂S₅/n-Si heterojunction were utilized to determine the barrier height (ϕ_b), diode ideality factor (n), and both series and shunt resistances. The C-V characteristic analysis shows that the prepared PbSb₂S₅/n-Si heterojunction is an abrupt junction. The power conversion efficiency of the prepared heterojunction has been calculated from the J-V characteristics under illuminations and was found to be 3.72%.

In this paper, we theoretically and experimentally investigated the structural, electronic, optical and magnetic properties of Cobalt doped ZnO. We used the the SPRAY Pyrolysis technique on preheated substrate glass. Samples were characterized using x-ray Diffraction. Optical parameters such as the optical band gap energy (Eg), the refractive index (n), the dielectric constants (r, i) and the optical conductivity (σ) as a function of photon energy have been investigated. As main result, 2% Co doping leads to improve the optical and optoelectronic properties of ZnO with a higher refractive index, optical conductivity and absorption near infrared region. Furthermore, we investigated the doping concentration effect on the magnetic and structural properties by first principal calculations and found a promising phase change temperature which is higher than room temperature.

Fe³⁺ doped ZnO was elaborated using spray pyrolysis deposition technique with different concentrations of the doping element then characterized by the x-ray diffraction for the structural characterizations of our samples. We investigated optical properties using Uv-Vis spectrophotometer in the wavelength range of 200–880 nm and also magnetic properties by first principal density functional theory electronic structure calculations to estimate the sample magnetic properties and the Curie temperature. The change in the physical parameters and its relation with the measured optical band gap were investigated in detail to understand the cause and to improve the optical and magnetic properties. The measured optical absorption spectra and band gap values are in agreement with the Ferromagnetic stability of the magnetic dopants charge states. The magnetic interaction was explained by the Zener p-d double exchange. The optimized structure was confirmed using the first-principle stability calculations.

Ni₃Al matrix self-lubricating composites containing multilayer graphene and Ag are successfully prepared by spark plasma sintering (SPS) and laser melting deposition (LMD), which are denoted as NMAS and NMAL, respectively. The sliding wear performances of NMAS and NMAL at 25–500 °C are systematically investigated. NMAL exhibits the lower friction coefficients (0.20–0.40) and considerable wear resistance (2.8–5.0 × 10⁻⁵ mm³ · N⁻¹ · m⁻¹) as compared to NMAS. For the use of spherical prealloyed powders and the manner of layer by layer deposition, the hardness distribution of NMAL is more uniform than that of NMAS. NMAL shows the better tribological properties in comparison to NMAS from 25 to 400 °C because of the good consistency of microhardness. NMAL has excellent tribological behavior at 400–500 °C, while NMAS exhibits poor tribological performance. An explanation for the result is that the lubricating film of NMAL is still intact at 400–500 °C, while the lubricating film of NMAS is cracked and peeled off.

In this paper, the effects of rolling reduction rates on the microstructure of the NM360/Q345R composite were studied. With the electron backscatter diffraction(EBSD) contribution, the microstructure evolution and recrystallization of the bonded interface were mainly analyzed at various reduction rates (30%, 50%, 70% and 80%). With the rolling reduction rate increased, the grains of the NM360 and the Q345R became low-sized and denser. With the reduction rate increase up to 80%, the grains of NM360 and Q345R formed the same low-sized equiaxed grains, whereas the two materials achieved a coordinated deformation. A continuous dynamic recrystallization mechanism existed in the NM360/Q345R composites. A high number of low-sized grains in the NM360/Q345R bonded interface existed, which were basically the recrystallized blue region and the deformed red region. Moreover, with the reduction rate increase up to 80%, the recrystallization of the NM360 was significantly difficult compared to the Q345R. Also, a high number of red high density deformation zones were formed in the NM360.

By first-principles calculation, we studied the elastic properties of face-centered cubic (FCC), body-centered cubic (BCC) and hexagonal high-entropy alloys (HEAs). A new model Maximum Entropy Approach (MaxEnt) was adopted. The lattice parameters, elastic constants, bulk moduli (B), shear moduli and Poisson's ratio were obtained and made a comparison with the available experimental data, the results show the accuracy of MaxEnt approach. Because of the periodic boundary condition, a smaller MaxEnt structure can not adequately represent the disordered state of HEA, a larger supercell would have been a lot closer to real disordered state of HEA. So the influence of supercell size on calculated results was studied. We found that supercell size shows significant influence on elastic properties, but the influence of magnetic is negligible. The calculated results of AlNb_1.5Ta_0.5Ti_1.5Zr_0.5 show that MaxEnt has the potential to simulate HEAs with complex element concentrations. The results of (HfZrTaNbTi)B₂ demonstrate the cocktail effect of HEAs.

Equal channel angular pressing (ECAP) not only affects the mechanical properties of pure copper but also the electrochemical behavior of copper. Thus, it would be interesting to perform a comprehensive analysis from a practical perspective. A three-dimensional (3D) simulation is carried out to reveal the strain distribution and field emission scanning electron microscopy (FESEM) is employed to investigate the microstructural evolution of copper in the course of six ECAP passes. It is found that the ECAP must be repeated enough times to bring about a significant grain refinement. This processing route will lead to observation of an ascending trend in all mechanical properties of copper except total elongation. The dislocation density shows the same ascending trend before it becomes saturated at the sixth pass. In order for copper to regain the usual homogeneity with respect to hardness, six ECAP passes are necessary. On the other hand, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) are all employed to understand the electrochemical behavior of ECAPed copper when immersed in 0.1 M NaOH solution. After the sixth pass, copper shows its best passive and protective behavior in this solution. Furthermore, Mott–Schottky analysis indicates that although the passive film of ECAPed copper still behaves as a p-type semiconductor, it becomes less defective or less conductive as the number of applied ECAP passes increase. Consequently, the most stable passive film forms on a copper sample that has gone through six passes of ECAP.

In this study, flexible Cu₅₀Zr₅₀ metallic glass fibers (MGFs) with a diameter of 50 μm were prepared by a melt extraction method. The microfibers were axially and radially uniform with a smooth surface. It was found that the elastic modulus of the micron-sized Cu₅₀Zr₅₀ MGFs was low and could increase towards the value of the bulk counterparts with multiple-loading tension. High resolution transmission electron microscopy (HRTEM) experimental observation verified that tensile stress could induce the nanostructural rearrangements in metallic glasses from disorder to short- and medium-range order. Meanwhile, this unique fact was explained by the potential energy landscape with multiple metastable states.

In the present study, friction and wear properties of bulk Fe₂B with different Cr additions were examined under dry friction and water lubrication conditions. The morphology, structure, mechanical properties and tribological properties were investigated by OM, SEM, XRD and XPS. The results show that there is no obvious new phase generated and the crystal structure has no changes with Cr addition. Cr element solubilizes in Fe₂B gains without any segregation, only bits of (Fe, Cr)₂B crystals formed. With the increasing of Cr addition, the fracture toughness increases first then decreases, and 2Cr sample has the highest toughness. Under dry friction condition, the friction coefficient and wear loss are all decrease first and then increase. 2Cr sample has the highest friction coefficient and wear loss. The tribochemical products form a lubricating film to reduce the friction coefficient and wear loss. And the wear mechanism is mainly brittle fracture. Under water lubrication condition, the friction coefficient drops remarkably, then slightly rises up. In contrast, the wear loss increases first and then decreases. 2Cr sample has the lowest friction coefficient, but the highest wear loss. The wear mechanism is mainly tribo-chemical wear in water. A comparison of the results under dry friction and water lubrication conditions, for the same sample, the friction coefficient is lower, but the wear loss is higher in water.

Nitrogen ions were implanted on the Aluminum Alloy 7075-T6 to study the structural and mechanical properties. The implantation was carried out at energy 1 MeV with ion doses ranging from 8 × 10¹⁴, 1.2 × 10¹⁵ and 5.2 × 10¹⁵ ions cm⁻². Structural analysis of all the samples was done by x-ray Diffractometer (XRD) for the implanted ions. Surface morphology of all the samples was studied by Scanning Electron Microscopy (SEM). Changes in the surface and structure are directly related to the dose of ion implantation. To understand the mechanical properties universal Tensile Testing Machine was applied. Modifications in the crystalline structure of the material exhibit new properties to the lattice site. Effects on the crystallite size and stress generated by the damage strongly vary the yield stress, ultimate tensile strength and percentage elongation of the material. Hardness was tested by the Vickers Micro Hardness Tester. The result shows that the surface hardness obtained at room temperature by implanting nitrogen ions initially decreases and then systematically increases due to subsequent damage. Graph representing yield stress, ultimate tensile strength and hardness are strongly agreed with each other. The micro structure indicates the fractured surface after Tensile Test.

Effect of mathematical misorientation on microstructures and properties of bicrystal superalloy RR2086 have been investigated. Prior to thermal exposure, precipitates of modified RR2086 bicrystals (BXs) at grain boundaries were mainly MCs. After the exposure, a reasonable amount of discontinuous and blocky M₂₃C₆ precipitates which were embedded in a γ' layer along the grain boundary were found at grain boundaries of the modified RR2086 BXs. This type of precipitates is known to be ductile and creep-resistant. No cellular M₂₃C₆ appeared during exposure. This structure results in improved creep performance of bicrystals of high-angle boundaries in the modified BXs compared to their base counterparts. The modified RR2086 BXs exhibited higher grain boundary creep resistance and higher grain boundary ductility of creep fracture. This is attributed to the grain boundary strengthening of the MC and M₂₃C₆ precipitates, the mechanical keying effect due to their coherence with one neighbouring grain, which effectively suppresses grain boundary sliding. The γ' layer also played an important role in improving creep resistance of the grain boundaries. The formation of a γ' layer along grain boundaries was initiated by the conversion of M₂₃C₆ in modified BXs.

This work deals with the tribo-mechanical behavior of the complex hypereutectic aluminum-silicon alloy Al–18Si–2.5Cu–0.6Fe (wt%) in the as-cast condition and the following compression through converging die under different reduction ratios (R) of 1.5 and 2.0 at working temperatures of 300, 400, and 500 °C. X-ray diffractometry pattern showed the formation of intermetallic compounds (β-Al_4.5FeSi and Al₂Cu) due to the higher temperature during the process run over. Microstructural features were characterized by scanning electron microscope, and remarkable grain refinement was observed in the compressed samples. Mechanical properties were adjudged by tensile test and microhardness test. There was significant improvement in the ultimate tensile strength and hardness of the compressed billets which may be attributed to grain refinement of the matrix and uniform dispersion of the fine Si particles and the intermetallic compounds. A pin-on-disc tribometer was used for the wear test. Higher wear resistance was observed in the compressed alloy as compared to the as-cast alloy due to the presence of the fine Si particles and strengthening of the matrix. The present work provides valuable insights into tribo-mechanical characteristics of the Al–18Si–2.5Cu–0.6Fe (wt%) alloy for broad industrial applications.

The inhibitive performance of Sapindus on the acidic corrosion of Aluminium was studied using myriad experimental and computational techniques. Sapindus showed 98% of inhibition efficiency at 2000 ppm. Inhibition efficiency of Sapindus was found to be directly proportional to its concentration in the acidic medium. Effect of temperature was also studied and it played a corrosive role by increasing the corrosion rate and decreasing the inhibition efficiency of Sapindus. Thermodynamic parameters of adsorption were derived to enunciate the findings. Mechanism of adsorption was also explored using electrochemical impedance spectroscopy and potentiodynamic polarization (Tafel) studies which displayed a profound physisorption mechanism.

The microstructures and the mechanical/electrical properties of graphene nanoplates-copper (GNPs-Cu; 0.4 wt%) composites and the composites doped by cobalt (GNPs: 0.4 wt%; Co: 2, 3, 4 wt%) have been researched, which have been prepared by mechanical alloying and spark plasma sintering (SPS) technology. It is found that GNPs disperse evenly in Cu matrix with the ball milling time of 6 h. The compressive strength and the hardness of GNPs-Cu are 601.88 MPa and 128 HV, respectively, which were increased by 3 times and 42.2% compared to pure Cu. And the IACS of the GNPs-Cu composites was 79%. The GNPs-Cu composites with 3 wt% Co (3 wt% Co-GNPs-Cu) also present excellent mechanical properties. The compressive strength and the hardness is 571.32 MPa and 145 HV, respectively, which is raised by 2.81 times and 61.1% compared to pure Cu. And the IACS of the 3 wt% Co-GNPs-Cu composites is 65%. In addition, based on the first principle calculation the mechanism of the effect of Co doping on the GNPs-Cu interface bonding has been studied. Our results provide experimental basis for the preparation of high strength and high conductivity Cu matrix composites, which can be widely used in many fields, such as high-strength magnetic field, heat exchange material, etc.

In this study, an in situ Al–30%Mg₂Si composite fabricated with the different addition of yttrium (Y) inoculation was investigated. Microstructural examinations were carried out via scanning electron microscope (SEM) and x-ray diffraction (XRD). The results showed that Y inoculation changed the morphology of primary Mg₂Si from coarse lotus-type particles to fine polyhedral shape. Furthermore, the average size of primary Mg₂Si particles decreased obviously. When the Y addition reached to 0.6%, the refinement of Al–30%Mg₂Si composite was the best. Similarly, the superior ultimate tensile stress (UTS), elongation at fracture (El), and Vicker's hardness (Hv) of Al–30%Mg₂Si composite were obtained. However, excess Y inoculation addition reduced refinement and mechanical properties because of Al₃Y phase aggregating.

The total strain-controlled creep-fatigue behavior of a first generation directionally-solidified Ni-based superalloy DZ445 at 900 °C in air was reported in the previous investigation. The deformation mechanisms with different dwell times for this superalloy were further expounded from the reduction in area, surface cracks, internal voids, stability of γ' strengthening phase, and dislocation characteristics in this investigation. The results demonstrated the reduction in area increased, the number of the surface cracks on the vertical section decreased and the number and area fraction of internal voids increased with the increase of tensile dwell time. The non-directional coarsening trend of the secondary γ' precipitate increases with increasing the dwell time. These microstructure changes affirmed that the deformation of DZ445 goes through transformations from the typical fatigue mode into the mixture of creep and fatigue, and further into the compound of creep and ductile when the dwell time is initially applied and continuously increased.

The nucleation of a eutectic alloy –at an early stage– and the factors that determine whether rod or hexagonal growth occurs were evaluated as a function of the process control agent (PCA)—or the lack of it. The study is subdivided into three separated experiments; in all cases, the samples (elemental powders of Pb and Sn) were processed by high-energy milling under composition, pressure and temperature (c-P-T) vial conditions. In the first case, it was detected an excessive mechanical kneading when the powders were processed without PCA and a monolith –as long as 5 mm in length– was obtained. However, this route should not be underestimated because the presence of α−, β− and eutectic-phases –at the surface of the monolith– were traced as nanoparticles (<100 nm). In the second and third cases, to prevent the excessive mechanical kneading and interparticle bond of the powders during milling, two different mechanochemical routes with PCA were considered: (i) tributyl phosphate (TBP) and (ii) ethanol (ETOH). Both of them were proposed to modify the viscoelastic behaviour of the powders. Nanorods resulted when TBP was used. Although structural disorder –at nanometric scale– was not traced, other effects associated with TBP like organic debris and the presence of by-products were detected. Based on the results with the ETOH option, it was shown that the precursors store energy as structural defects during milling. This suggests that the early eutectic nucleation (hexagonal crystal structure) occurred due to structural defects, crystals interfaces and phase boundaries. These acted as preferential sites for nucleation. Moreover, a typical eutectic phase distribution was detected. Finally, it was demonstrated that even after prolonged milling time and nonetheless the kind of PCA –or the lack of it, only the eutectic formation was scarcely traced; that is to say, a partial eutectic formation took place.

The microstructures and mechanical properties of Mg-5Y-2Nd-xSm-0.5Zr (x = 0, 1, 3, 5) alloys were investigated. The results indicated that a new Mg₄₁Sm₅ phase was generated in the as-cast Sm-containing alloys. As the Sm content was increased, the grain of α-Mg matrix was refined and the amount of second phases at the grain boundary increased. After the solution and aging treatment, a large number of β' phases precipitated, the alloys mainly consisted of α-Mg, Mg₂₄Y₅, Mg₄₁Nd₅ and Mg₄₁Sm₅. The grain size significantly reduces from 80 μm to 23 μm with the increasing of Sm content. Under all conditions in this paper, Mg-5Y-2Nd-3Sm-0.5Zr alloy had the best mechanical properties. The tensile strength and elongation of the aged Mg-5Y-2Nd-3Sm-0.5Zr alloy were 296.9 MPa, 4.78% room temperature and 279.4 MPa, 6.43% at 250 °C, respectively. The mechanical properties of this alloy is obviously superior to the commercial WE54 alloy with equivalent total rare earth content, which has excellent heat resistance and can be reliably applied below 250 °C. The improving of the mechanical properties is mainly due to grain refining strengthening, solid solution strengthening and precipitation strengthening of the β'-Mg₄₁Sm₅ phase.

Blue/red emitting bi-phase Eu³⁺/Eu²⁺-doped SrPCl-based phosphors were synthesized using a co-precipitation method followed by sintering process in air ambient and in reducing gas. The effect of sintering/reducing temperature and Eu concentration on the structure, morphology and luminescent spectra were investigated. XRD patterns analysis showed that the phosphors contain bi-phase of Sr₅(PO₄)₃Cl and Sr₃(PO₄)₂ due to the decomposition of Cl atoms at high sintering temperature. The decomposition, however, could be prevented by high Eu doping content. The optimum PL performances are obtained for the phosphor sintering/reducing at 1000 °C and with Eu doping concentration of 5.5%. The relative intensity of the red and blue emission from the bi-phase Sr₅(PO₄)₃Cl/Sr₃(PO₄)₂ phosphor could be controlled by controlling the reducing temperature. At low reducing temperatures of 400 to 650 °C, dual red and blue emission Eu³⁺/Eu²⁺ bi-phase SrPCl phosphor can be achieved. Being stable and can be well excited by UV excitation source, the blue/red emitting bi-phase Eu³⁺/Eu²⁺-doped SrPCl-based phosphor is a potential candidate for plant growth LEDs.

The present study investigated the effect of the welding heat input on friction stir-welded copper/brass dissimilar joints with an overlap design. For this purpose, the friction stir welding (FSW) process and the rotational non-consumable of H13 hot work tool steel were used. For the overlap joint, the copper was selected as advancing side and the brass was used as retreating side. In order to study the microstructure and fracture surface of the welded samples, an optical microscope and a scanning electron microscope (SEM) were used. In addition, the mechanical behavior of the joint was tested through tensile-shear and microhardness tests. It was found that the copper and brass are formed as layered onion rings in the weld nugget zone (WNZ), and they gradually complete with an increased welding heat input. Maximum microhardness was observed in the WNZ in all the samples. Due to onion ring structure, the microhardness was observed as an M-shaped form in this zone, and the greatest microhardness was related to brass and the smallest microhardness was related to copper. The mechanical properties including tensile-shear strength and microhardness were increased by decreasing the welding heat input. Hence, the maximum tensile strength and microhardness were observed in Sample 450 rpm-16 mm min⁻¹. The fractography of the fracture surfaces of the samples showed that ductile failure occurred in all the samples and fracture type tended to brittle fracture for bigger welding heat inputs. Finally, the best mechanical and microstructural results were observed in Sample 450 rpm-16 mm min⁻¹ due to smaller welding heat inputs as compared to the other two samples.

Al-Zn-Mg alloys are considered difficult to weld using fusion welding techniques. In the present study AA7475 has been welded with in-process cooling using two different cooling conditions. The mechanical properties have been carefully examined along with the micro-structural evolution. Improvements in the mechanical properties were observed. It was found that severe plastic deformation and in-process cooling resulted in extremely fine grains in the SZ region. Extremely good microstructural stability was observed in each of the samples especially ice water slush. Cooling has resulted in exceptional mechanical properties and hardness in the welds. The welds were characterized using SEM and EDX was also done on each of the samples. EDX data revealed high density of strengthening precipitates in the boundaries of the TMAZ and SZ. It also revealed high weight density of Mg along the zone interfaces.

Corrosion and lubricated sliding tribological behavior of Al-TiB₂-nano Gr hybrid composites for varying wt% of reinforcements are studied. Composites fabricated in ultrasonic vibration assisted stir-cast method are characterized using optical micrographs and SEM images. Micro-hardness values of composites increases with incorporation of both TiB₂ and nano-Gr bases while hardness decreases with addition of only nano-Gr phase. Corrosion characteristics are investigated using potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Corrosion resistance of composites is tailored from the parameters like corrosion potential, corrosion current, linear polarization resistance. Results show that corrosion potential shifts to negative direction with incorporation of reinforcing phases. Nano-Gr intensifies the corrosion of aluminum base matrix through hindering the corrosion path. Presence of TiB₂ phase does not alter that effect of nano-Gr. Formation of protective film on the surface of Al-2.5TiB₂-nano Gr composites is apprehended through impedance tests. The corroded surfaces are studied using SEM images and the morphologies reveal that localized corrosion occurs through formation of pit. Such localized corrosion is yielded by the formation of galvanic cell in between reinforcing phases (TiB₂, nano-Gr) and base matrix in presence of electrolyte solution. Tribological characterization is performed under lubricated sliding. Composite surface does not react with the concerned lubricant. Without any change in the amount of solid lubricant (nano-Gr) or TiB₂, wear and friction behavior of composites enhanced sufficiently in presence of liquid lubricant at contact surface compared to dry condition.

For high carbon chrominum steel, better comprehensive mechanical properties were obtained after low temperature bainitic treatment compared to martensitic, but much longer duration time was taken simultaneously. Therefore, the transformation kinetic of low-temperature bainite was investigated in this paper. The database of TCFE7 of Thermo-Calc software was used to calculate the T₀ line. DIL805A dilatometer was used to simulate the heat treatment. The microstructure was observed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and x-ray diffraction (XRD). The mechanical properties were tested by multifunctional tensile testing machine. The results indicate that the holding times at intercritical austenitization temperature influence the subsequent bainitic transformation. Under-cooled austenite (UA) has different stability after different bainitic holding times, and transforms into martensite while cooling to room temperature if the holding time is less than 1200 s. Pre-strain at different temperatures or different pre-strains at the same temperature shorten the incubation time and accelerate the initial bainitic transformation, but have negligible effect on the full transformation process. The transformation from austenite into bainite could be accelerated by a novel two-step heat treatment in which the isothermal temperature is increased to a higher temperature at the second step. The rational cooperation of the two-step process sharply reduces the lower bainitic transformation time to about 27% percent of the conventional full transformation process.

The microstructure and mechanical properties of the conventional and hybrid friction stir welded joints of a TRIP steel were investigated. For the aim of hybrid welding, oxy acetylene flame assisted process was conducted. Optical microscopy, x-ray diffraction, and microhardness test were used to evaluate the microstructure and mechanical properties. The results showed that the stir zone composed of mainly the martensite and retained austenite. The volume fraction of the retained austenite of the base metal i.e. 9.84% was decreased to the 5.73% and 5.09, respectively at the stir zone of the conventional and hybrid joints. Indeed, the retained austenite in the TRIP steel microstructure was transformed to martensite under the thermal cycle and deformation induced by rotational tool. However, hybrid operation induced more martensite formation in the microstructure because it caused higher peak temperature. As a result, the microhardness profiles of the hybrid weldment showed the higher hardness in the stir zone in compare with that of conventional process.