The effect of ?-ray on the copolymerization of 1-Vinylimidazole (VIm) onto polyvinyl fluoride (PVDF) is dependent on the absorbed dose, various solvents, and Iron concentration (II). Using radiation-induced grafting techniques, develop an alternative proton-exchange membrane (PEM) based on PVDF as the primary polymer and VIm as the monomer. Gravimetric analysis, FTIR, and conductivity investigation were utilized to characterize the physico-chemical properties of the grafting membrane. PEM, also known as PVDF-g-P1VIm, was synthesized and functionalized by sulfuric acid doping. The proportion of dose absorbed, the degree of grafting (DG), the ion exchange capacity (IEC), and water uptake (WU) all correlate with the membrane grafting performance. The C-H bonds exhibited decreased intensity and the peak location moved considerably in FTIR, indicating PVDF-VIm grafting. DG and IEC influence the ionic conductivity of the grafting PEM. The grafted membranes proved to have humidity dependent on proton conductivity with a range of 0.136 mScm-1 (room temperature) and 3.02 mScm-1 (373 K) containing IEC levels of 0.065 and 0.107 meq./g, respectively. PVDF-g-P1VIm membranes exhibit potential in the field of PEM membranes for use in hydrogen fuel cells or water treatment.

Titanium dioxide (TiO2) and TiO2 doped with impurities offer good potential for many applications such as photoanode in dye-sensitized solar cells (DSSCs) and photocatalysts used in hydrogen production and degradation of organic pollutants. First-principles calculations on the structural, electronic and optical properties of pure anatase TiO2 with different Nd concentrations are performed using 2 x 1 x 1 supercell with a stoichiometry of Ti1-xNdxO2 (x = 0, 0.0625, 0.125 and 0.1875). The doping effect to the properties of TiO2 can be observed from the changes in the structural parameters, modification of the band structure, presence of impurity energy levels (IELs) in density of states (DOS) and difference in optical properties results. At a higher Nd concentration doping, the band gap of Nd-doped TiO2 decreases as a result of the overlapping of states among Nd 4f, Ti 3d and O 2p, which can enhance the light absorption activity in the visible light region. These findings indicate that Nddoped TiO2 can increase the performance of photocatalyst and photovoltaic due to its capability to harvest visible light.

Polymer electrolytes based on agarose dissolved in DMSO solvent complexed with different weight percentages of Mg(NO3)2 ranging from 0 to 35 wt% were prepared using a solution casting method. Electrochemical impedance spectroscopy (EIS) was applied to study the electrical properties of this polymer electrolyte, such as ionic conductivity at room and different temperatures, dielectric and modulus properties. The highest conducting film has been obtained at 1.48 × 10−5 S·cm−1 by doping 30 wt% of Mg(NO3)2 into the polymer matrix at room temperature. This high ionic conductivity value is achieved due to the increase in the amorphous nature of the polymer electrolyte, as proven by X-ray diffractometry (XRD), where broadening of the amorphous peak can be observed. The intermolecular interactions between agarose and Mg(NO3)2 are studied by Fourier transform infrared (FTIR) spectroscopy by observing the presence of –OH, –CH, N–H, CH3, C–O–C, C–OH, C–C and 3,6-anhydrogalactose bridges in the FTIR spectra. The electrochemical properties for the highest conducting agarose–Mg(NO3)2 polymer electrolyte are stable up to 3.57 V, which is determined by using linear sweep voltammetry (LSV) and supported by cyclic voltammetry (CV) that proves the presence of Mg2+ conduction.

PbTiO3 has emerged as a promising material for the thermoelectric application. In this study, we proposed to use density functional theory to investigate the underlying mechanism for improving the thermoelectric efficiency of ATiO3. The thermoelectric parameters of the designed surface structures have been obtained by using the Boltzmann transport equation approximation. The properties of the structure, electronic, and thermoelectricity were measured and analyzed. The surface (001) modification through the AO termination layer has increased the electrical conductivity, thus increasing the power factor. On the other hand, increasing the Seebeck coefficient, which is aided by declining thermal conductivity, which is aided by low thermopower, improves the figure of merit. It is shown that the thermoelectric performance of surface (001) SnTiO3 is higher as compared to PbTiO3 making it interesting towards lead-free materials in thin-film application.

Polymer gel electrolytes based on potato starch as biopolymer and potassium hydroxide salt are prepared. The ionic conductivity and dielectric constant of the polymer gel electrolyte samples are investigated using electrochemical impedance spectroscopy over a frequency range from 50 Hz to 1 MHz. The optimum room temperature conductivity attained for this electrolyte is 5.08 x 10(-1) S cm(-1) at 6.0 M KOH. Meanwhile, the frequency-dependent AC conductivity in this electrolyte system adheres to Jonscher's power law. The plot of power law exponent against temperature indicates small polaron hopping (SPH) model is most applicable to describe the conduction mechanism in potato starch-KOH biopolymer electrolyte system.

Composite grafted polymer electrolyte based on chitosan grafted poly(methyl methacrylate) (Ch-g-PMMA) have been prepared and investigated. The lithium triflouromethanesulfate salt (LiCF3SO3 or LiTf), ethylene carbonate (EC) and SiO2 and are applied as a salt, plasticizer and ceramic filler, to the polymer host systems. Impedance spectroscopy was performed in the room temperature. The highest conductivity of 1.63 x 10(-4)Scm(-1) was obtained for the grafted polymer with 50wt% LiCF3SO3 and enhanced to 2.23 x 10(-4)Scm(-1) with the addition of 30% EC. The conductivity is further enhanced to 4.21 x 10(-4)Scm(-1) with the addition of 6wt% of SiO2. FTIR and X-ray diffraction studies show that complexation and the ionic transport has taken place which is mainly in the amorphous phase. The electrical conductivity value measured by ac impedance spectroscopy is found to depend upon the SiO2 concentration.

First-principles calculations on phase stability of three polymorphs of titanium dioxide (TiO2) in rutile, anatase and brookite phases are performed using density functional theory (DFT) and density functional theory plus Hubbard U (DFT+U) methods within generalized gradient approximation (GGA) for Perdew-Burke-Ernzerhof for solids (GGA-PBEsol) functional. The calculated cohesive energy with respect to the volume per formula unit of TiO2 is analyzed to evaluate the phase stability sequence for the TiO2 phases between rutile, anatase, and brookite. The results for the phase stability show good agreement with other theoretical reports. However, the difficult situation occurs for DFT in predicting correctly the phase stability of the rutile, anatase and brookite phases. Thus, the GGA-PBEsol+U for Ti 3d of TiO2 with U = 2, 4, 6 and 8eV are used to determine the effect of U on the phase stability. The DFT+U approach shows good agreement with the existing experimental data for the order of stability of TiO2 which give a good description of the phase stability of TiO2.

Wire electrical discharge machining is a material removal process of electrically conductive materials by the thermo-electric source of energy. This kind of machining extensively used in machining of materials with highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using wire electro-discharge machining with brass wire diameter 0.5mm.The objective of this work is to study the influence of three machining parameters namely peak current, pulse off time and wire tension to kerf width followed by suggesting the best operating parameters towards good machining characteristics. A full factorial experimental design was used with variation of peak current, feed rate and wire tension, with results evaluated using analysis of variance techniques (ANOVA). The test array was further extended to allow for the implementation of Response Surface Methodology (RSM) analysis in order to develop first and second order models for the prediction of kerf width response. The results showed that average percentage error between the predicted and experimental value for kerf width models was less than 2%.

Polymer gel electrolytes based on cellulose acetate with lithium bis(oxalato) borate salt were prepared by dissolving in gamma-butyrolactone solvent. The ionic conductivity and dielectric constant of the polymer gel electrolyte samples are investigated using electrochemical impedance spectroscopy over a frequency range from 100 Hz to 1 MHz. The ionic conductivity increased with increasing in the cellulose acetate concentration up to 2.4 wt.% (1.41 x 10(-2) S cm(-1)) and thereafter decreased. The relationship between the dielectric constant and ionic conductivity has been interpreted. The optimum conducting polymer gel electrolyte shows electrochemical stability up to 4.7 V versus Li.

Wire electrical discharge machining is a material removal process of electrically conductive materials by the thermo-electric source of energy. This kind of machining extensively used in machining of materials with highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using wire electro-discharge machining with brass wire diameter 0.5mm.The objective of this work is to study the influence of three machining parameters namely peak current, pulse off time and wire tension to cutting rate, material removal rate, surface roughness and kerf width followed by suggesting the best operating parameters towards good machining characteristics. A full factorial experimental design was used with variation of peak current, feed rate and wire tension, with results evaluated using analysis of variance techniques. Parameter levels were chosen based on best practice and results from preliminary testing. Main effects plots and percentage contribution ratios are included for the main factors and their interactions.

This paper presents an investigation on influences and multiple optimizations of wire-electrical discharge (WEDM) machining performances such as cutting rate, material removal, surface roughness and kerf width processed on titanium alloy material. The experimental studies were conducted under varying machining parameters namely pulse-off time, peak current, wire tension and wire feed. The experimental works were designed base on Taguchi design of experiment. The optimum multi-objective performance characteristics was determined using analysis of variance (ANOVA) coupled with grey relational analysis (GRA). ANOVA was used to study the significance of process parameters on grey relational grade which showed the most significant factor. The grey relational grade obtained from GRA was used to optimize the wire-electrical discharge machining process. To validate the findings, confirmation experiment had been carried out using the optimal parameters and the predicted results were found in good agreements with experimental finding. Improved machining performance in the wire electrical machining process has been achieved by using this approach.

Wire electrical discharge machining (WEDM) is a material removal process of electrically conductive materials by the thermo-electric source of energy which is extensively used in machining of materials for a highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using WEDM with a brass wire diameter of 0.25mm.The objective of this work is to study the influence of three machining parameters, namely peak current (IP), feed rate (FC) and wire tension (WT) to cutting speed and surface roughness. Response Surface Methodology was used to develop second order model in order to predict cutting rate and surface roughness responses. The results showed that the average percentage error between the predicted and experimental value for both models was less than 2%.Furthermore, the developed models were used for multiple-response optimization by desirability function approach to determine the optimum machining parameters. These optimized machining parameters are validated experimentally, and it is observed that the response values are in good agreement with the predicted values.

This paper presents an investigation on the effect and optimization of machining parameters on the kerf (cutting width) and material removal rate (MRR) of titanium alloy (TI-6AL-4V) using wire electrical discharge machining WEDM with a brass wire diameter of 0.5mm. The experimental studies were conducted under varyingpulse-off time, peak current, wire feed and wire tension. The settings of machining parameters were determined by using Taguchi experimental design method. The multiple performance characteristics based on the statistical-based analysis of variance (ANOVA) and grey relational analysis (GRA) was attempted. Analysis of variance was used to study the significance of process parameters on grey relational grade (GRG) which showed the most significant factor. The GRG obtained from the GRA was used to optimize the WEDM process. The optimum process parameters are determined by the GRG as the overall performance index. To validate the findings, confirmation experiment had been carried out at the optimal set of parameters, and the predicted results were found to be in good agreements with experimental findings. Improved machining performance in the WEDM process has been achieved by using this approach.

Wire electro discharge machining (WEDM) operations are dynamic in nature and process responses are related with simultaneous variation of parameters during experiments. To make the process reliable and to study the effects of the process parameters on different responses such as surface roughness (Ra), cutting rate and material removal rate (MRR), attempts have been made to carry out experiments considering the WEDM process parameters. Taguchi method, which is a design of experiments (DoE) method, has been applied to the present experiment followed by Grey Relational Analysis. The signals to noise (S/N) ratio plots are analyzed to study the effect of the process parameters. The adequacy of the above analysis has been tested through the implementation analysis of variance (ANOVA). Next, multi-objective optimization of the response analysis is performed. As the Taguchi methodology is unable to perform multi-objective optimization of the response characteristics, combined approach of orthogonal array and Grey Relational Analysis (GRA) are carried out. Optimal combination of process parameters has been proposed in the machining of titanium alloy in order to achieve minimum surface roughness (Ra), higher cutting rate (CR) and higher material removal rate (MRR). Finally, confirmation tests are carried out to verify the findings.

Plasticized grafted polymer electrolytes composed of chitosan-grafted-poly(methylmethacrylate) (Ch- g-PMMA), ethylene carbonate (EC) plasticizer and lithium triflate (LiTf) salt were prepared by the solution cast technique. Impedance spectroscopy was performed in the temperature range of 303-373 K. The highest conductivity of 1.63 x 10-4 Scm-1 was obtained for the salted grafted polymer with 50 wt% and enhanced to 2.23 x 10-4 Scm-1 with the addition of 30 wt.% EC. The temperature dependence conductivity data obeys Arrhenius relationship. Dielectric behavior was analyzed using complex permittivity (s) and electrical modulus formalism (M) for the highest conducting unplasticized and plasticized samples at various temperatures. The structure and complexation of the electrolyte were studied by Fourier transform infrared (FTIR) spectroscopy.

Wire electrical discharge machining (WEDM) is a material removal process of electrically conductive materials by the thermo-electric source of energy which is extensively used in machining of materials for a highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using WEDM with a brass wire diameter of 0.25mm.The objective of this work is to study the influence of three machining parameters, namely peak current (IP), feed rate (FC) and wire tension (WT) to cutting speed and surface roughness as a responses. Response Surface Methodology was used to develop second order model in order to predict cutting speed and surface roughness responses. The results showed that the average percentage error between the predicted and experimental value for both models was less than 2%. Effects of each parameter and their interaction with percentage contribution ratios (PCR) are included for each response.

Cross-linked composite membranes of sulfonated poly(ether ether ketone) (SPEEK) with a chitosan content up to 50 wt%, were prepared by solution cast technique and ultraviolet (UV) curing. A mixture of sulfonated poly(ether ether ketone)-chitosan (SPEEK-CS) membranes was prepared by dissolving SPEEK in dimethyl sulfoxide (DMSO) and chitosan (CS) in acetic acid. The homogen formed was later irradiated with an UV source to induce crosslinking. The membranes were then characterized by evaluating infrared spectra, proton conductivity, water uptake, degree of swelling and ion exchange capacity (IEC). The Fourier transform infrared (FTIR) study revealed considerable interaction between the sulfonic acid functions of SPEEK and amino groups of chitosan. Proton conductivity decreases with increasing of chitosan content from 8.51 × 10-3 to 2.85 × 10-7 S cm-1. Meanwhile, water uptake decreases with increasing of chitosan content from 52% to 29% and IEC 0.188 to 0.018 mequi. However, the swelling properties unchanged as the chitosan content increases.

Proton exchange membrane (PEM) was prepared by radiation-induced grafting of 1-vinylimidazole (VIm) onto poly(vinylidene fluoride), (PVDF) film. The PVDF film was soaked with VIm mixture solution undergo mutual irradiated by y-ray. The different concentrations of VIm from 0.5 to 3.0 M in 1,4-dioxane as solvent and ferrous sulfate as a initiator were prepared. The conductivity of the irradiated PEMs in humidity dependent was determined at different temperatures between 273 and 373 K. The results showed the proton conductivity of the membrane increased up to 10-3 S cm-1 at absorbed dose 60 kGy. Grafting yield, conductivity, spectroscopic, thermal analysis and surface morphology study manifested that VIm was successfully grafted onto the PVDF backbone. The finding showed that grafting yield increased in the PVDF membrane associated with absorbed dose. In fact, the surface morphology of the membrane observed homogenous when grafting with the VIm after irradiation that in compliment with XRD study. The PVDF-co-VIm membrane is expected to be a promising candidate for the PEM fuel cell.

A new material for proton conducting electrolyte base on sulfonated poly(vinylidene flouride-hexafluoropropylene) (PVDF-HFP)/1H-1,2,4-Triazole (TriA) membrane operating at low relative humidity and has capability to self-humidify were investigated. Different concentrations of TriA and sulfamic or amidosulfonic acid (H3NSO3) in PVDF-HFP were prepared. The pores of a porous PVDF-HFP were packed with proton carrier, TriA and sulfamic acid (SFA). The samples were then exposed to γ-rays of up to 50 kGy. The effects of high energy γ-rays irradiation onto these proton conducting membranes have been observed. The surface morphology was analysed by scanning electron microscopy (SEM). The ionic conductivity of the irradiated membrane was determined using impedance spectroscopy (IS) at different temperatures between 30 oC and 100 oC. The results showed that the pores membranes shrinkage after irradiation and proton conductivity of the membrane increased when the absorbed dose up to 30 kGy and after which the proton conductivity decreased with increasing of absorbed dose.