International Journal of Modern Physics B

As the Perovskite-type Lanthanum Cobalt Oxide of LaCoO₃ is nontoxic and thermally stable even at high temperature, this material is expected as a candidate for thermoelectric applications. The thermoelectric performance of a material is often evaluated by the dimensionless figure-of-merit, ZT (=S${}^2\sigma$T/$\kappa$), or S${}^2\sigma$ in the ZT equation. S${}^2\sigma$ shows the electrical characteristic as a Power factor (PF). It has been reported Seebeck coefficient of LaCoO₃ is higher than other oxide materials at room temperature even though electrical conductivity and ZT are lower values. In this study, calcium-doped lanthanum cobaltite La${}_{1-x}$Ca${}_x$CoO₃ (x = 0.00, 0.05, 0.10 and 0.15) and iron-doped lanthanum cobaltite LaCo${}_{1-y}$Fe${}_y$O₃ (y = 0.05, 0.10 and 0.15) have been prepared by solid-phase process. The X-ray diffraction patterns of the calcium-doped samples and iron-doped samples show cubic perovskite structure. Electric conductivities were improved by Ca or Fe substitution and showed a tendency to increase with increasing the temperature. The sample substituted with Fe 5 mol.% showed the maximum PF, 0.510 ($\mu$ W/K²m) at 548 K, and the sample substituted with Ca 15 mol.% showed the maximum PF, 0.152 ($\mu$ W/K²m) at 498 K.

This paper describes the dynamics modeling, structural analysis of UCR. First of all, the system configuration of UCR and structural analysis are introduced. After that, 3-DOF equation of UCR is introduced for an analysis of motion performance through a numerical simulation, and applying the LOS method at the UCR for path following. Finally, the performance of the proposed path tracking method is verified through simulation and experiments using small test platform.

The semiconductor ZnO has gained great interest in the past decades because of its wide bandgap and large exciton binding energy. Especially, the doping and embedded metal nano-particles methods could improve the conductivity of ZnO thin films, which made it possible to fabricate transparent conducting oxides based on ZnO. In the present study, Al-doped ZnO thin layer was employed to manipulate the electrical and optical properties. The band engineering in ZnO makes it possible to manipulate the absorption, emission, reflection spectral of ZnO via the embedded quantum well layer. The ZnO thin films with excellent performance in electrical conductivity and optical transmittance are promising to be applied in the devices including the lager flat screen, touch panel, portable digital device and smart windows. In the present study, we summarized the recent progress in ZnO with embedded metal nanoparticles and application in TCOs.

The present work deals with sinter-forged powder metallurgical (P/M) steels alloyed with chromium by addition of ferrochrome powder, which allows a close control over the chromium contents of alloy steels. Chromium contents can be varied by adjusting appropriately weighed ferrochrome powder in the P/M mixtures. Fe–Cu (2%) and C (0.7%) is the base composition for this P/M alloy steel. Study with the addition of 0.5% and 3% chromium by weight in the form of ferrochrome powder is carried out. The P/M alloy steel of base composition with no chromium content is also prepared for comparative study. The paper deals with these three alloy steels formed by the sinter-forging technique of powder metallurgy. The results of hardness and wear in hardened and tempered condition are reported in the present work.

The effects of solvents on the structural stability of cross-linked lysozyme crystals were investigated by an immersion test using alkaline (0.1 M ammonia [NH₃] and 0.1 M sodium hydroxide [NaOH]), acidic (0.1 M acetic acid [CH₃COOH] and 0.1 M hydrochloric acid [HCl]) and organic (50% [v/v] and undiluted ethanol, acetone, 2-propanol and dimethyl sulfoxide [DMSO]) solvents. The morphology and lattice constants were monitored by optical microscopy and X-ray crystallography. The cross-linked crystals exhibited good stability against NH₃, CH₃COOH, HCl, ethanol, acetone and 2-propanol. However, samples preserved in DMSO and NaOH were severely degraded.

Polyaniline (PANI) is one of conducting polymers (CPs) which has been used widely in various fields of applications. The low cost monomer, red/ox reversibility, existence of various oxidation states, electrical & optical activity, environmental stability, etc. are the characteristic reasons for it. Herein, we report the electrochemically synthesized PANI and its composite with single-walled carbon nanotube (SWNTs) — PANI/SWNTs. The effects of inculcation of SWNTs were studied using the electrochemical properties of PANI and PANI/SWNTs composites, using the electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) for the electro active natures of both. For the study of optical absorption UV–visible (UV–Vis) spectroscopy was used and for morphology the field effect scanning electron mictroscopy (FESEM) was used. The composite PANI/SWNTs exhibited a good electroactive nature and therefore was opted as a sensing platform for the detection of nickel ions. For the selectivity inculcation of the nickel ions, the chelating ligand viz. dimethylglyoxime (DMG) was used for the modification of the composite.

To eliminate the complexity of curvature extrusion process, a new extrusion method was proposed. In this study, a finite element analysis for curvature extrusion was studied to commercialize this extrusion method that creates curvature in a tilting method. When simulating an extrusion process, it is important to fix the appropriate friction coefficient and fillet value to avoid peel-out problems such that the finite element disappears. Therefore, the actual extrusion results and the simulated results were compared to find conditions that the element would not disappear. There was a good agreement between the simulation and experimental results when the coefficient friction was 0.4 and the fillet was 0.4 mm.

Aluminum (0.5 at.%)-doped ZnO (AZO) thin films were deposited by pulsed laser deposition technique (PLD) in oxygen ambient of 10${}^{-6}$ Torr. The deposited thin films were characterized by x-ray diffraction (XRD), photoluminescence (PL), Raman spectroscopy and uv–visible spectroscopy (UV–vis). Next, graphene oxide (GO) was synthesized by Hummers method and was characterized by XRD, UV–vis spectroscopy, Raman spectroscopy and transmission electron microscopy (TEM). Thereafter, GO solution was drop-casted on AZO thin films. These films were then characterized by Raman Spectroscopy, UV–vis spectroscopy and PL. Attempt is being made to comprehend the modifications in properties brought about by integration.

In the present study, the field emission properties of multi-walled carbon nanotubes (MWCNTs) treated with laser ablation have been investigated. The MWCNTs were synthesized by chemical vapor deposition method. The laser ablation treatment was performed in liquid medium for laser ablation time of 40 min and 60 min. The morphology of MWCNTs films was characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The results exhibit that the field emission properties of MWCNTs are dependent on the laser ablation time. The Raman spectra of laser-ablated MWCNTs clearly showed disorder and increase in graphitic content. The SEM and TEM results clearly revealed the separation of MWCNTs after laser ablation treatment. The field emission characteristics of the MWCNTs showed that the turn-on fields and current density are improved for the nanotubes treated with laser ablation. The enhancement in the field emission characteristics of MWCNTs is attributed to the disorder as well as the increase in the aspect ratio which causes more pathways for electron emission.

Nb₂O₅ layer were deposited on ZnO by using doctor blade method. The preparation of a bilayered ZnO/Nb₂O₅ photoanode was introduce for dye-sensitized solar cell (DSSC) application. Deposition of Nb₂O₅ layer on ZnO film improves power conversion efficiency of DSSCs. The ZnO/Nb₂O₅photoanode-based DSSCs show increase in photocurrent, open circuit voltage and conversion efficiency. The ZnO/Nb₂O₅ solar cell provides 50 mV increase of open circuit voltage, $\sim 16\%$ increment in current density and $\sim 10\%$ increment in efficiency as compare to ZnO-based DSSCs. We further analyzed the electron recombination properties of ZnO and ZnO/Nb₂O₅ by utilizing electrochemical impedance spectroscopy (EIS). The EIS analysis (Bode Plot) for ZnO/Nb₂O₅ photoanode show shifting of the peak related to electron recombination towards low frequency as compared to ZnO photoanode. Thus, there is an increase in lifetime of electrons in the ZnO/Nb₂O₅ photoanode, confirming that the recombination reactions are reduced in ZnO/Nb₂O₅ photoanode as compared to the ZnO.

In this study, we synthesized copper hydroxide nanosheet and investigated its electrochemical property and how to deposit it with a uniform amount. The precursor of the nanosheet was a layered copper hydroxide synthesized by the ion exchange of dodecylbenzene sulfonate (DBS) with acetate in Cu₂(OH)₃(CH₃COO)⋅H₂O. The nanosheet was prepared by delamination of the layered copper hydroxide by dispersion in 1-butanol. Atomic force microscopy (AFM) images of the nanosheets showed lateral dimensions of ca. 2 $\mu$m with the height of ca. 4.5 nm. Cyclic voltammogram of the nanosheet in basic solution showed two cathodic peaks and two anodic peaks similar to the copper oxide electrode. To deposit the nanosheet, a quartz glass slide was dipped in the dispersion of the nanosheet in 1-butanol and dried after washing. This procedure was repeated and the ultraviolet (UV) and visible (Vis) light absorption spectrum of the slide was measured. The absorbance of the slide increased in direct proportion to the number of times of the dip-and-dry procedure. Thus, we confirmed that a controlled amount of nanosheet was deposited on the quartz glass.

The purpose of this study is to determine the correct estimation of the concept design for high strength composites applied to the intermediate shaft of a ship. Recently, the application of composites has increased in the ship industry area for weight reduction and marine environmental protection. Carbon fiber reinforced plastic (CFRP) has characteristics of high strength, high elasticity and high corrosion resistance. Therefore, it is a suitable material for reducing the weight of the ship. So, weight reduction and high fuel efficiency can be expected. However, little research has been carried out on the technology development of a composites shaft for ships. In this study, analysis is carried out on the application of a high-strength CFRP shaft.

A photoanode using dye-sensitized ZnO nanowire (NW) is a good candidate for low-cost, colorful, light-weight and flexible solar cell material. We have synthesized a ZnO NW anode and a ZnO nanowire–nanoparticle (NWNP) anode, in which ZnO nanoparticles (NPs) are decollated on the surface of NWs. Photo-induced electron transfer dynamics from the excited state of sensitizer dye (D149) to the conduction band of ZnO NW and ZnO NWNP was clarified using femtosecond transient absorption spectroscopy. The decay of the single excited state ($S_1$) of D149 was faster in ZnO NW than that of ZnO NWNP, indicating that NW is more suitable as an efficient electron acceptor.

To improve solder-joint reliability, the Sn–3.0Ag–0.5Cu (SAC) solder had minor Ge and Pd additions to form composite solders. The results indicated that the Cu₆Sn₅ and Cu₃Sn phases formed at the SAC–$x$Ge/Cu interface ($x=0$, 0.5, 1.0, 2.0 wt.%) and the Ag₃Sn phase precipitated in the solder. Cu₆Sn₅ and Cu₃Sn phases formed at the interface and PdSn₄ phase in the solder when the SAC–1.0Pd and SAC–2.0Pd reacted with the Cu. The SAC–1.0 Pd solder had the lowest liquidus temperature, and Ge addition improved the wettability.

This study investigates an analysis of the healing behavior of carbon-based nanocomposites by using the finite element (FE) method and provides the quantitative healing values based on the efficiency with respect to the volume, C${}_h=1-$V${}_{\mathrm{\text{healed}}}$/V${}_{\mathrm{\text{nonhealed}}}$. An approximation of the geometrical relationship on the profile was considered, and the results compared with the model were used to estimate the healing efficiency based on the initial open profiles. In this model, it contains the interface elements between damaged crack faces. We adjust their sizes and stiffness of elements to compare the profiles with a geometrical equation. We propose that the results of their efficiencies can be compared with the strength of the healing elements that depend on the size of healed volume by the approximation.

This study presents the electrical properties of graphene that directly is contact on two types of p-type GaN thin films. The diameter of several hundred nanometer V-pits were formed on the p-GaN thin films by adjusting the NH₃ flow rate during the metal organic chemical vapor deposition epitaxial process. The single-layer graphene with a high transmittance of 97% in the visible range was transferred on p-GaN thin films to form an Ohmic contact. The V-pits provide more carrier transport paths that promote the carrier tunneling into p-GaN thin films, resulting in a better Ohmic contact performance. In addition, the increased current value was attributed to the presence of V-pits on the p-GaN thin films.

In this study, dissimilar material welding between Alloy617 and 12Cr steel was performed using buttering welding technology on to the 12Cr steel side. Then, the welding residual stress of dissimilar material weld was analyzed by the numerical method and the experimental method, after that, the stress amplitude including the welding residual stress was calculated using a modified Goodman equation.

In this study, Pb-free solders were bonded to soda-lime glass and fused quartz plates using the ultrasonic assisted soldering (UAS) method. The solder–glass interfaces were observed and analyzed to clarify the effect of the elements in the solder and glass bonding behavior. As a result, the Sn–Zn solder was bonded to glass without the intermetallic compound (IMC) layer. However, the Sn–Ag–Cu solder was not able to bond to glass even though ultrasonication was performed during the soldering process. Chemical shifts for Zn 2p and O 1s spectra were observed at the interface by X-ray photoelectron spectroscopy (XPS) analysis, which is attributed to the chemical bonding between the substrates and elements in solder alloy. In conclusion, O in the substrate and Zn in the solder were important to form the bond between the glass and solder.

Fretting occurs at the contact area between two materials under load and in the presence of minute relative surface motion by vibration or external force. Bearings, clutches, riveted and bolted lap joints are subjected to fretting damage. Friction coefficient, materials of the specimen, contact surface pressure, relative slip amplitudes, temperatures and environment have an effect on the fretting. In this study, fretting wear test is conducted with SCM415 (Cr–Mo alloy steel) which are much used for making gears and shafts because of its excellent machinability, good mechanical properties and low cost, compared with those of the existing machine structural steels. In order to determine the fretting wear type, fretting wear fixture which can be attached to the servo hydraulic fatigue testing machine is made. And then, specimens and fretting pad with a constant curvature are made of SCM415 materials. Different normal forces and displacement amplitudes are applied to the fretting pad and diamond-like carbon (DLC) is coated on the fretting pad for fretting wear test.

The halide-activated pack cementation method was utilized to deposit aluminide or silicide coatings on Inconel 617 and Hastelloy X superalloys. Aluminide and silicide diffusion coatings were formed at 850${}^{\circ }$C for 2 h in nitrogen atmosphere, using a pack mixture containing pure aluminum (Al) or silicon (Si) and aluminum oxide (Al₂O₃) powders with activators of NH₄Cl and AlF₃. Aluminide-coated alloys showed homogeneous and uniform microstructures. Al diffused into the alloy inwards and aluminide diffusion coatings of $\sim$17 $\mu$m thick were formed inside the alloy. It was shown that the Al coatings played a key role in blocking off the excessive corrosion products at a high temperature for the alloys. The enhanced thermal stability and improved wear resistance were achieved in the aluminide coatings. In contrast to the aluminide coating, the silicide coating played a negative role, unable to provide the protective layer. The microstructural evolution and thermal stability of the aluminide- and silicide-coated alloys have been elucidated.

The bending and impacting characteristics of sandwich composites containing corrugated paper (CP) as a core layer are discussed herein. The core layer of the sandwich composite was fabricated with CP-reinforced polylactic acid (PLA) resin. The core layer was then stacked with jute fabric and PLA films on the top and bottom surfaces to fabricate the sandwich composites. Two composites [CP-reinforced PLA composite (CP/PLA composite)] and jute fabric/PLA sandwich composite with CP as a core layer [J/PLA/CP composite] were developed in this study. To manufacture the CP/PLA composite core layer, a dipping bath was used for impregnating the paper with a molten PLA solution. The resin film method combined with a hot press was used to produce the jute fabric/PLA/CP sandwich composites. A material test system (MTS810) was used to study the bending properties of the composites. Further, an IZOD impacting instrument was used to examine the impacting characteristics of the composites. Both the CP/PLA and jute fabric/PLA/CP sandwich composites increase the energy absorption capacity in the impact test.

In aerospace, aircraft weight is one of the important factors essential for long range and high fuel efficiency. Instead of fastening, bonding methods like co-curing, co-bonding and secondary bonding are used on the aircraft parts. Secondary bonding was developed for integrated parts because of easy handling, less defect ratio and low cost. During manufacturing, the integrated parts using secondary bonding, bonding strength can show a wide range of failure strengths. Due to inconstant failure strength, the design value can be dropped and reinforcement methods should be applied. To avoid over-designing and to get a constant value for failure, the adhesive failure cases are studied in this project. In this study, L joining composite parts are investigated under tensile loading. Different conditions are tested to select a suitable manufacturing method for secondary bonding methods. From the experimental results, the secondary bonding was sensitive at exposed temperature/time and shape conditions of the fillet. The results show that the failure strength depends on the shape of fillet and exposed time for curing.

The dissolution behavior of the Ni substrate and Ni₃Sn₄ phase was studied in the following molten lead-free solders: Sn, (wt.%) Sn–3.0Ag–0.5Cu (SAC), Sn–0.7Cu (SC), Sn–58Bi (SB) and Sn–9Zn (SZ) at 240${}^{\circ }$C, 270${}^{\circ }$C and 300${}^{\circ }$C. The dissolution rate of the Ni substrate in solder decreased from Sn, SAC, SC, SB, to SZ. The thick Ni₅(Zn, Sn)${}_{21}$ phase formed at the SZ/Ni interface hindering the Ni dissolution. Ni₃Sn₄ phase dissolution rate in molten solder decreased from Sn, SZ, SAC, SC, to SB at 240${}^{\circ }$C and SC, Sn, SAC, SZ, to SB at 300${}^{\circ }$C. The (Cu, Ni)₆Sn₅ phase spilling was observed at the SAC/Ni₃Sn₄ and SC/Ni₃Sn₄ interfaces. Zn in the SZ solder reacted with the Ni₃Sn₄ phase to form the (Ni, Sn)₅Zn${}_{21}$ phase at the interface.

We have investigated strain mediated magnetoelectric (ME) coupling and impedance properties in 0.5Zn${}_{0.3}$Ni${}_{0.7}$Fe₂O₄–0.5HoMnO₃ nanocomposites at room-temperature. The ME voltage is measured in both longitudinal and transverse direction at a frequency of 173 Hz. The impedance, real and imaginary parts of impedance and dielectric constant have been carried out in presence of DC magnetic field. With the application of magnetic field, slight decrease in dielectric constant has been observed. The impedance, real and imaginary parts of impedance are found to increase with the increase in the applied magnetic field. Nyquist plots have been fitted using three parallel combinations of resistances–capacitance circuits. Fitted parameters show the dominant role of grain boundaries, grains and interface of two types of grains of the sample.

This study was evaluated by changing the mass loss ratio and the strength maintenance ratios of the fibers after treatment. The fibers were treated with sodium hydroxide and hydrochloric acid solutions for different amount of times. The environmental resistance was analyzed by changing the time of treatment in NaOH and HCl solutions. The fibers’ surface corrosion morphologies were analyzed using the optical microscope. The acid resistance was much better than the alkali resistance for the basalt and slag fibers. Nevertheless, the situation for the glass fibers was different: the acid resistance was almost the same as the alkali resistance. Between the two types of aqueous environments evaluated, the alkali solution is the most aggressive to the fibers’ surface.

Leaching of metallic species from denitration catalyst waste was performed at different leaching conditions using different solvents. The leaching efficiency of sodium percarbonate solution was higher than that of hydrogen peroxide (H₂O₂) or sodium carbonate solution. Under the optimal leaching conditions (1.0 mol kg${}^{-1}$ sodium percarbonate, leaching temperature of 80${}^{\circ }$C and leaching time of 5 h), the leaching rate was 90.7 ± 2.9% for W, 78.4 ± 4.1% for V and 8.6 ± 0.4% for Ti. The enhanced leaching ability of sodium percarbonate was due to the high affinity of the peroxo moiety (–O–O–) of H₂O₂, within the percarbonate, towards metallic ions and dissolution of titanium dioxide (TiO₂) in the alkaline medium of carbonate.

A feasibility study was done on a novel concept to design and develop a low-cost disdrometer and wind turbulence hybrid sensor in a single device. It employs the principles of electromagnetic induction and response of a cantilever to impulses. Based on these principles, a device was designed and fabricated to detect the rain droplet size and wind turbulence. It was fabricated from readily available materials. The testing of the device in laboratory conditions yielded satisfactory results as compared to the standard commercial instruments.

The laser ablation of a noble target material in a liquid is known as an alternative physical method for nanostructure fabrication. In the present study, the nanosecond laser ablation is used to irradiate MoS₂ in water to produce MoS₂ nanosheets. The experiments of laser ablation time of 20 minutes and 120 minutes have been carried out to study their field emission properties. Transmission electron microscopy (TEM) and Raman spectroscopy have been used to reveal surface and structural morphology. It is observed that the laser ablation time is an important factor in determining the size of MoS₂ nanostructure. The Raman spectra of laser ablation confirm the formation of MoS₂ nanosheets and removal of molybdenum oxide species. The TEM shows the size of MoS₂ microsheet has been reduced from 2 $\mu$m to 400 nm after the laser ablation treatment. It is found that the turn-on fields are reduced and current densities of MoS₂ are increased after the laser ablation. The enhancement in the field emission characteristics of MoS₂ is due to the reduction in the size of MoS₂ and removal of molybdenum oxide species. The nanostructures produced by laser ablation may be used for optoelectronic application.

In this research, hull structure of Ray-type Underwater Glider (RUG) that could be a next generation unmanned vehicle was studied. RUG is capable of long-term operation at higher speeds than conventional cylindrical underwater gliders due to its ray shaped body composed of dual buoyancy engine. For long-term operation, it is necessary to develop a lightweight control housing and battery case. For this reason, the carbon fiber container was used to be lighter and stronger than duralumin used in the past. Through the stress and buckling analysis, it was shown that the container was able to withstand the pressure of 200 m which is the target water depth with the safety ratio of about 1.8 times. Using a carbon composite material, the mechanical strength can be maintained while reducing the weight of the pressure vessel by more than 40% compared with the high tensile aluminum material.

Fibrous membranes are promising separators for high-performance lithium ion battery because of their high porosity and superior electrolyte uptake. In this paper, the fabrication of hybrid gel polymer electrolyte (HGPE) by introducing SnO₂ nanoparticles in poly(vinylidine fluoride) by electrospinning technique and soaking the electrospun nanofibrous membranes in 1 M LiPF₆ in ethylene carbonate (EC)/diethyl carbonate (DEC) (1:1, v/v). The as-prepared electrospun HGPE with SnO₂ nanofiller was characterized by scanning electron microscopy. The influence of SnO₂ on the structure of polymer membrane, physical, and electrochemical properties is systematically investigated. HGPE shows significant high ionic conductivity 4.6 × 10${}^{-3}$ S/cm at room-temperature and better cell performance such as discharge C-rate capability and cycle performance. The hybrid gel polymer nanofibrous membrane favors high uptake of lithium electrolyte so that electrolyte leakage is reduced. The gel polymer electrolyte with SnO₂ filler was used for the fabrication of Li/PVdF-SnO₂/LiFePO₄ coin cell. The fabricated cell was evaluated at a current density of 0.2 C-rate and delivered stable and excellent cycle performance. This study revealed that the prepared HGPE can be employed as potential electrolyte for lithium ion batteries.

The purpose of this study is to determine the correct estimation of laminate patterns for high-strength composites applied to a ship. Recently, the need for developing a ship component has been increasing to improve the capability of maritime operations. Composites with excellent specific strength and specific stiffness are emerging as next-generation materials. In the composite material, the mechanical properties vary depending on the laminated pattern of the reinforcing material. Therefore, in this study, the properties of the composite materials were calculated using the computer simulation program. The ply calibration performance results show that the initial values of the mechanical properties of the carbon/epoxy composites in the E11 direction are higher than the calculated values, and the remaining values are the same. The laminate mechanics results show that the tensile strength in the S11T direction was 1515 MPa, which is almost the same as the initial value of 1500 MPa.

In this paper, we report the development of a new green, eco-friendly pathway for the synthesis of reduced graphene oxide (RGO). In a typical experiment, graphene oxide (GO) was prepared by the oxidation of graphite powder using Hummer’s method. Prepared GO was then subjected to reduction by using extract of Tagetes erecta (Marigold flower). The samples were characterized by various techniques such as X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) spectroscopy and Raman spectroscopy. RGO synthesized in this work is being probed for diverse applications including biomedical applications.

The aim of the present study is to synthesize the Bi(Cd0.45Ti0.45Fe0.10)O₃ (BCTF45/10) nanoceramics by solid state reaction ceramic method at an ambient temperature. Therefore, a raw material in stoichiometric ratios of carbonates and oxide powder was employed to obtain a precursor of the BCTF45/10 nanoceramics. The as-prepared mixture is calcined at 1010 K for 4 h in an air atmosphere. Preliminary structural and surface morphological analyses were carried out using powder X-ray diffractometer and scanning electron microscopy technique, respectively. X-ray analysis of synthesized compound shows the formation of single-phase orthorhombic structure with an average crystallite size of 25 nm. The sintered bodies have relative density above 95%. A correlation between both dielectric parameter of the as-synthesized compounds were also discussed in a wide temperature (298–673 K) and different operated frequency range (1–750 kHz). Addition of Cd/Ti affected the ferroelectric property of the BiFeO₃ due to contribution from the leakage current.

In this study, halloysite nanotubes (HNTs) were heat-treated at various temperatures in order to minimize particle aggregation, and the mechanical properties in the humid environment was compared and analyzed to prevent the pore formation and achieve an optimal bonding with epoxy resin. As a result, the glass fiber-reinforced plastic (GFRP), with 0.5 wt.% heat-treated HNT at 700${}^{\circ }$C, showed the highest moisture absorption resistance, tensile strength and interlaminar shear strength.

We report the growth of Cu₂SnS₃ (CTS) thin films on F-doped SnO₂ (FTO) glass substrates at room-temperature by low-cost electrodeposition technique using an aqueous medium without the evolution of hydrogen. Electrolyte concentration and deposition potential were optimized under the limits of water hydrolysis. As-deposited films are post-annealed in the presence of the sulphur flakes to establish the stoichiometry. The annealed films were found to contain high phase purity and favorable optical properties to be useful for the photovoltaic applications. Optical data reveal that the CTS films have direct optical bandgap of 1.25 eV with an absorption coefficient of the order of 10⁴ cm${}^{-1}$. A photovoltaic cell architecture of Glass/FTO (back contact)/CTS/CdS/Al:ZnO/Al (front contact) exhibited an open circuit voltage of 28 mV, a short circuit current density of 8.4 $\mu$A/cm² and the fill factor of 25%. The absorber thickness optimization and the use of Mo-coated glass as a back contact improve the solar cell parameters. A further study in this aspect is under way.

Aluminum alloy 6061 is widely used for space development since the advent of space era irradiated with protons using cyclotron. In the condition of confined 5-mm thick wall, protons of 5 MeV, the case of low energy showed larger damage in the structure of aluminum alloy than those of 25.4 MeV, the case of high energy. Protons of 5 MeV stopped and transferred all kinetic energy into the 5-mm thick wall, on the other hand, protons of 25.4 MeV were penetrating and a few energy transferred. Elastic modulus reduced, but elongation was increased, finally tensile strength obviously showed that longer duration of exposure yielded weaker strength of material.

Growing interest in fundamental research on two-dimensional transition metal chalcogenides (TMDs) is rising rapidly due to their excellent physical and chemical properties. One such materials is Boron nitride (BN), an electrical insulator with a band gap of 5.5 eV, which possesses a high chemical stability, excellent mechanical properties and high thermal conductivity. Cubic BN (c-BN) and hexagonal BN (h-BN) are kinds of layered materials similar to that of graphite-like structure in which planar networks of BN hexagons are regularly stacked. In the present study, we report a general approach for the production of BN nanostructures using nanosecond laser ablation (Nd:YAG, 532 nm) in acetone at room-temperature. The laser ablation time was varied for 30, 120 and 240 min. The prepared BN nanostructures were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) to identify the formation of nanostructure. The presence of BN nanoparticle has been confirmed by SEM images and supported by XRD spectrum. It is expected that the BN nanoparticles have practical importance for optoelectronic devices and their applications in the near future.

The spectroscopic study of La₂O₃ thin films deposited over Si and SiC at low RF power of 25 W by using indigenously developed plasma-enhanced atomic layer deposition (IDPEALD) system has been investigated. The tris (cyclopentadienyl) lanthanum (III) and O₂ plasma were used as a source precursor of lanthanum and oxygen, respectively. The $\sim$1.2 nm thick La₂O₃ over SiC and Si has been formed based on our recipe confirmed by means of cross-sectional transmission electron microscopy. The structural characterization of deposited films was performed by means of X-ray photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD). The XPS result confirms the formation of 3${}^{+}$ oxidation state of the lanthania. The XRD results reveals that, deposited La₂O₃ films deposited on SiC are amorphous in nature compare to that of films on Si. The AFM micrograph shows the lowest roughness of 0.26 nm for 30 cycles of La₂O₃ thin films.

In this study, we focused on the investigation of phosphate removal using calcium oxide (CaO) and calcium hydroxide (Ca(OH)₂) which are mainly from the calcined shells as adsorbents. Hydroxylapatite Ca${}_{10}$(PO₄)₆(OH)₂, the component of industrial fertilizer was formed after the adsorption process following the XRD results. The phosphate removal increased from 20% to 97% with the aid of the mixture of flocculants alginic acid (AA), NaHCO₃ and CaCl${}_2\cdot$ 2H₂O in the case of 50 ppm phosphate concentration when the samples were filtered through 2.7 $\mu$m particle retention filter paper which is roughly equivalent to the case of phosphate removal rate of 0.2 $\mu$m membrane filter paper without flocculants (99%). The results suggest that AA, NaHCO₃ and CaCl${}_2\cdot$2H₂O as the flocculants are effective for phosphate removal from 20 to 100 ppm.

For the fabrication of polymer-based composite materials, the interpretation of an appropriate fabrication process is essential to improve the productivity and manufacturing process. In this study, the wet prepreg forming process was used to fabricate carbon fiber reinforced plastic (CFRP) and different curing cycles were demonstrated for an optimal process. To determine the range of curing temperature, a pretreatment on differential scanning calorimetry (DSC) analysis was performed. After that, tensile and ILSS tests were adopted to investigate the mechanical properties and thermal analysis on a matrix carried out by the DSC equipment. Different volumes of the matrix residue on fractured fiber, which represent the matrix-reinforcement adhesion strength, were observed by a scanning electron microscope (SEM). Also, a void aggregation was found in high curing temperature situation due to excessive exotherm. Both the tensile strength and ILSS held a certain trend with the changing curing cycles. The highest tensile strength (469 MPa) and glass transition temperature (Tg) at 91.58${}^{\circ }$C occurred at 80${}^{\circ }$C and 12 h curing temperature and time, respectively. The result of ILSS had an almost opposite tendency of the tensile strength. A correlation between Tg and mechanical properties was observed and it can be extensively applied to optimize the manufacturing process.

In semiconductor wafer manufacturing, wire sawing is the first machining process to slice an ingot into hundreds of wafers. The cutting tool is a tiny wire which is wound on the wire guides. The material of the wire guides is essential to stabilize the process and to control the wafer thickness. However, there are few studies on the materials and the properties of the wire guides. In order to enhance the performance of wire sawing, this study investigated wire sawing process with the guides made of polyurethane reinforced by nanoTiO₂ (PU/TiO₂) and nanographite (PU/graphite). The results show the PU reinforced by nanoTiO₂ was outperformed in wear resistance, although the surface roughness was slightly worse than the PU reinforced by nanographite.

The present study describes the results on the formation of WS₂ nanosheets using the nanosecond laser ablation in a liquid environment. The laser ablation in liquid is a well-known method and is widely used for the generation of nanostructure. The nanosecond laser ablation is used to irradiate WS₂ in a isopropyl alcohol to generate WS₂ nanosheets. The laser ablation time was 120 min. The field emission measurement of irradiated WS₂ nanostructures was performed. The Bulk and WS₂ were used to characterize the Transmission Electron Microscopy (TEM) and Raman spectroscopy to reveal their surface and structural morphology. It is found that the laser ablation time is an important parameter to transform the bulk WS₂ into WS₂ nanosheets. The generation of WS₂ nanosheets is revealed by the Raman spectra. Moreover, the TEM images indicate that the size of WS₂ microsheet has been reduced to 400 nm after the laser ablation treatment. It is also found that the field emission current density of WS₂ is increased after the laser ablation. The improvement in the field emission characteristics of WS₂ is due to the formation of WS₂ as well as the separation of layered WS₂ structure into few layers of WS₂. The formation of WS₂ nanosheets can be used for future optoelectronic devices.

This research investigated the feasibility of effective cost filter materials for groundwater purification in the small and medium scale households in Vietnamese rural areas. The trial models could treat 30 L of groundwater with aeration flow 5 L/min for 15 min. After 24 h of sedimentation, the water was filtered through layers of gravel (h = 11 cm), sea sand (h = 11 cm), activated carbon (h = 15 cm), manganese sand (h = 12 cm), sea sand (h = 11 cm) and gravel (h = 11 cm). After treatment process, the concentration of Fe and Mn ions of the output trial models was lower than the Vietnamese standard for drinking water. The model has a simple structure and easy assembly for washing the filter materials which continued to be used for the next filtration process. These models provide in rural areas, where it promising solutions for supplying drinking water to households is difficult to get clean ground water.

Cellulose is found in the cell wall of plant fibers in the form of nanofibers. The Young’s modulus of the crystalline portion is close to 140 GPa whereas the tensile strength of nanofibers is estimated to be above 2 GPa. Cellulose nanofiber has the potential to become an environmentally benign substitute for conventional reinforcements, but the overall cost of production is prohibitive due to the high energy demand and low yields of the mainstream processes, along with the need for expensive devices for proper extraction. This study proposes the use of an affordable kitchen blender adapted to extract cellulose nanofiber from agricultural crop byproducts to reduce production cost. Preliminary results showed that blending of pulp fibers from grass straw produces nanofibers similar to commercially available morphologies. So far, the raw material for nanofiber extraction has been mainly pulp fibers from wood, but the availability of cellulose in plant cells other than fibers would make nanofibers accessible to a wider research community and accelerate the development of cellulose-based nanocomposites.

Silicon-based anode materials in recent years has gained tremendous interest due to high theoretical specific capacity for next generation lithium ion battery. Some biomass, such as rice husks (RHs), has contained a lot of inorganic silicon, which are abundant in all the countryside and farmland. Considering that RHs are mainly composed of organic lignin, cellulose, hemicellulose, and inorganic Si compound, they could be used to prepare low-cost electrode materials, such as carbonaceous and silicon-based anode materials. In this work, we will present the synthesis of various anode materials from RHs with prominent performance for lithium ion battery application, such as porous C/SiO${}_x$ composites and Al-doped porous carbonized RHs husks composites.

In order to overcome the weak bonding force between the interface of the composite materials, research for improving the interfacial bonding force by adding nanoparticles has been actively conducted. However, despite the improvement of characteristics through the addition of nanoparticles, it is not widely used because the particles are relatively expensive and it is difficult to control the aggregation between the particles. In this study, we compared the mechanical properties of relatively low-cost halloysite nanotube (HNT) nanoparticles with micro-sized milled carbon. Based on the similar mechanical properties of the composites with two particles added, we found that milled carbon could replace HNT particles. In addition, if the cohesion of HNT is reduced based on the strengthening effect of milled carbon having a relatively low cohesive strength, it is expected that the strengthening effect can be obtained more than that found in the existing studies.

It is important that the steel plate is manufactured with a high tensile strength to reduce the weight of the body. It is generally accepted that twinning induced plasticity (TWIP) steel is a special steel with not only a high ductility but also a high-tensile strength compared to general steel. While numerous investigations have been carried out on the TWIP steel with an amount of manganese of at least 20%, the investigation of steel with manganese content of less than 20% has seldom been considered until now. In this study, the TWIP steel with manganese of less than 20% (12Mn, 15Mn and 18Mn TWIP steel) was investigated to determine the corrosion properties using electrochemical method. The 18Mn and 12Mn samples exhibited the best and worst corrosion resistance, respectively. It is suggested that the 18Mn sample forms a stable oxide film on the surface because it contains a larger amount of manganese and aluminum compared to the other samples, and their composition enables the easy formation of the oxide film.

This paper studies the effects of plain-woven fabrics of jute and cotton, used as reinforcements, on the mechanical properties of composite panels prepared using epoxy and polylactic acid (PLA) resins as matrix materials. Two different composites were prepared in the current study — natural fiber fabrics reinforced thermosetting epoxy resin and the same fabrics reinforced thermoplastic PLA resin. Two methods were used to manufacture these composites. The thermosetting composites were manufactured by impregnating the epoxy resin with the fabrics by hand lamination. On the other hand, the resin film method was used to manufacture the thermoplastic composites. Tensile, compression and 3-point bending tests were performed on the composite panels. The experimental results indicated that the compressive strengths of cotton/PLA and cotton/epoxy composites are approximately equivalent. The jute-based composites exhibited brittle failure in the tensile test. Furthermore, the 3-point-bending break strength of the cotton/PLA composites was higher than that of the jute/PLA composites.

In this paper, we report the safe removal of methyl orange (MO) dye from aqueous solution using chemical interaction of dye molecule with polyaniline/zinc oxide (PANI/ZnO) nanocomposite. PANI/ZnO nanocomposite has been prepared by in situ polymerization. PANI/ZnO nanocomposite was found to be the best promising candidate for adsorption of dyes due to more porosities compared to that of pure PANI. In the present investigation, PANI/ZnO nanocomposite was mixed in a solution of MO dye and used for adsorption process. Color removal was studied using UV-Vis spectroscopy and the spectra were recorded for specific time interval and validation of kinetic model has been applied. Absorbance of PANI/ZnO nanocomposite was found to be increased as compared to that of pure ZnO nanoparticles and pure PANI due to synergistic effect. Comparatively, the removal of dye was also found to be more by using PANI/ZnO nanocomposites. In order to evaluate kinetic mechanism the pseudo-first-order model, pseudo-second-order model and intraparticle diffusion models were verified by the linear equation analysis. Adsorption mechanism of pseudo-second-order model was systematically explained for removal of dye using PANI/ZnO nanocomposite. The results clearly demonstrated that the adsorption mechanism gives very novel and green method of removal of hazardous dyes from waste water.

This work examines the flexural and impact behavior of self-reinforced poly(ethylene terephthalate) (srPET) composites, which were produced by film stacking from fabrics composed of braiding commingled yarns with high-tenacity PET (serving as the reinforcements) and copolymerized PET (mPET) (serving as the matrix). The influence of the hybrid yarns, fabric architectures, and processing conditions on the mechanical properties of srPETs were studied.