Materials Science

Machining with minimum quantity lubrication (MQL) has gained widespread attention to boost machining performance of difficult to machine materials such as Ni-Cr alloys, especially to reduce the negative impact of conventional flooded machining on environment and machine operator health. The present study is aimed to evaluate MQL face milling performance of Inconel 625 using nano cutting fluid based on vegetable oil mixed with multi-walled carbon nanotubes (MWCNT). Experiments were designed with 2-level factorial design methodology. ANOVA test and desirability optimisation method were employed to arrive at optimised milling parameters to achieve minimum tool wear and machined surface quality. Experiments were performed under nanoparticles based minimum quantity lubrication (NMQL) conditions using different weight concentrations of MWCNT in base oil: 0.50, 0.75, 1, 1.25 and 1.5 wt. %; and pure MQL environment (without nanoparticles). The optimal MQL milling parameters found are cuttin...

Environment friendly machining calls for minimizing the use of cutting fluids to reduce their negative impact on environment and operator health. Present experimental work is aimed to investigate machining performance of AISI 304 austenitic stainless steel with PVD coated carbide tool under different turning environments viz. dry, flooded and nanofluid minimum quantity lubrication (NF-MQL). Optimum turning parameters obtained through desirability function optimisation are found as: cutting speed of 160.67 m/min, feed of 0.06 mm/rev and depth of cut of 0.25 mm with predicted tool flank wear of 100.001 μm and surface roughness of 0.509 μm at 0.808 desirability level. Confirmation tests show 3.22% and 3.41% error between predicted and experimental values of Vb and Ra, respectively. Present study has established the superiority of NF-MQL machining over dry and flooded machining. The most salient achievement of this investigation is the reduction of tool flank wear by 32.26% under NF-MQL...

Ectoparasites play a vital role in the transmission of zoonotic diseases and are an essential component of the ecosystem. However, very few studies have been conducted on the ectoparasites of small mammals in Ethiopia, particularly in the Chilalo-Galama Mountains Range. Therefore, this study aimed to determine the species composition, prevalence, distribution, and small mammal host interaction of ectoparasites in the study area. Different traps were used to capture small mammals from where ectoparasites were recovered. The collected ectoparasites were identified to families, genera, and species levels. The parameters like prevalence (P), Abundance (A), mean abundance (MA), Relative Abundance (RA), mean intensity (MI) and constituent ratio (C) were used for the analysis. The study identified disease-carrying ectoparasites based on presence absence of parasite for public and domestic animal health risks. Out of the 204 small mammals examined, 150 were infected by one or more groups of...

A simplified approach for analyzing the biofilm process in deriving an easy model has been presented. This simplified biofilm model formulated correlations between substrate concentration in the influent/effluent and at biofilm-liquid interface along with substrate flux and biofilm thickness. The model essentially considered the external mass transport according to Fick's Law, steady state substrate as well as biomass balance for attached growth microorganisms. In substrate utilization, Monod growth kinetics has been followed incorporating relevant boundary conditions at the liquid-biofilm interface and at the attachment surface. The numerical solution of equations was accomplished using Runge-Kutta method and accordingly an integrated computer program was developed. The model has been successfully applied in a distinct set of trials with varying range of representative input variables. The model performance was compared with available existing methods and it was found an easy, accurate method that can be used for process design of biofilm reactor.

Knotty tearing is a phenomena normally observed in reinforced black-filled natural rubber (NR) vulcanizate but not in gum NR vulcanizate. Unfortunately the underlying cause of knotty tear is still not fully understood and need to be unraveled. Many factors contribute to knotty tear behavior which include suppression of strain-induce crystallization, protein content of latex, vulcanization temperature and pre-vulcanization and post-vulcanization of latex. In this study, we concentrate on varying the maturation time during compounding process in filled NR latex (NRL) to study knotty tear behavior. The maturation time were varied in the range (0 – 72) hrs; and the tear deviation were measured to determine the extent of knotty tear phenomena. It was found that at the optimum maturation time of 24 hrs samples show highest tearing energy and show knotty tear phenomena with the least angle of tear deviation.

The present experimental investigation aims to analyse the effect of various machining parameters, such as pulse peak current (Ion), pulse on time (Ton), pulse off time (Toff) and spark voltage (SV) on the surface roughness (SR) and material removal rate(MRR) by using continuous traveling of both wire electrode (i.e. brass wire and zinc-coated brass wire). The present work also analyses the effect of types of wires, such as brass wire and zinc-coated brass wire used during machining of Titanium alloy (Ti-6Al-4V) on Surface roughness (SR) and material removal rate (MRR). This work studies the correlation between various response parameter such SR and MRR by using same machining parameter by for both wires.

In electrowetting, a droplet/substrate contact angle is modulated by applying a potential difference between the droplet and the substrate. Typically, the droplet potential is changed via an auxiliary electrode dipped in the droplet. Here, it is shown that electrochemical reactions lead to a potential drop on the auxiliary electrode in electrowetting, which degrades the droplet contact angle modulation. The magnitude of this effect depends on the voltage polarity. This problem can be addressed by using a dielectric layer, such as SiO 2 , which can prevent electrochemical reactions with the electrowetting substrate and the auxiliary electrode.

To understand the role of water on titanium SCC properties in methanol solutions, composition and structure of the passive film were studied using X-ray photoelectron and electrochemical impedance spectroscopies. The passive film consists of the inner compact layer and a porous outer layer. The inner layer thickness is less than 4 nm and decreases with the increasing water content. Water improves the passive film properties, thus changes SCC susceptibility by altering the hydrogen bonding of methanol and reacting with titanium preferentially.

Floating electrode electrowetting is caused by dc voltage applied to a liquid droplet on the Cytop surface, without electrical connection to the substrate. The effect is caused by the charge separation in the floating electrode. A highly resistive thermally grown SiO2 layer underneath the Cytop enables the droplet to hold charges without leakage, which is the key contribution. Electrowetting with a SiO2 layer shows a memory effect, where the wetting angle stays the same after the auxiliary electrode is removed from the droplet in both conventional and floating electrode electrowetting. Floating electrode electrowetting provides an alternative configuration for developing advanced electrowetting-based devices.

This work presents an electrowetting system in which the actuation direction depends on the polarity of the applied voltage. Since electrowetting response depends on the voltage squared, it is typically independent of voltage sign to first order. However, the introduction of an electrochemical diode into the equivalent electrical circuit permits polarity-dependent behavior. Electrochemical diodes were created by making holes in the dielectric. The aluminum electrodes passivate and prevent current flow in one direction, creating diodelike electrical behavior with high breakdown voltage. The resulting actuation forces were directly measured and are of comparable magnitude for both actuation directions.

PurposeOne way to analyze electrochemical signals is the wavelet transform, which transforms a signal into another representation whereby the signal information is presented in a multi‐scale manner. Using the inverse wavelet transform, it is also possible to split a signal into different components of different frequency intervals. The inverse wavelet transform is the concept underpinning this paper, the aim of which is to demonstrate that high‐frequency variations in current signals are as valuable as low‐frequency variations.Design/methodology/approachThe set‐up for the experiments carried out consisted of two identical carbon steel working electrodes exposed to simulated concrete pore solution, sparged simultaneously with SO2 and CO2. The corresponding electrochemical current signal was studied using wavelet transform.FindingsHigh‐frequency components of current signals are as informative as low‐frequency components. High‐frequency variations could show some electrochemical activ...

Electrowetting on dielectric is demonstrated with a thin spin-coated fluoropolymer over an aluminum electrode. Previous efforts to use thin spin-coated dielectric layers for electrowetting have shown limited success due to defects in the layers. However, when used with a citric acid electrolyte and anodic voltages, repeatable droplet actuation is achieved for 5000 cycles with an actuation of just 10 V. This offers the potential for low voltage electrowetting systems that can be manufactured with a simple low-cost process.

This study presents solute transport experiments and simulations conducted in a horizontallymounted glass bead micromodel. The glass bead micromodel of novel design, with one layer of glass beads fused between two glass plates, simulates an ideal porous medium. Various scale levels of solute transport through the micromodel were observed experimentally and recorded on video tape for use with image analyzers. Results were analyzed with image analyzers to obtain relative concentration plots for the bulk micromodel and at various points in the model. The results show favorable comparisons of experimental and numerical data. The glass bead micromodel study was a feasible procedure for quantifying micromodel experiments.

To provide insight into the mechanism of bubble migration in in situ air sparging in a coarse porous medium, the rise of air bubbles through a granular porous medium is studied through video photography enhanced with image analysis. The porous medium is simulated by a fully saturated cylindrical glass column filled with 4-mm glass beads in random packing order. The experimental procedure for introducing and visualizing a single air bubble is discussed, and the average rise velocity as a function of the emerging bubble radius is directly measured. Compressed air is injected into the base of the column through the use of an electronically controlled solenoid valve. The resulting bubble motion is recorded by camcorder, and still frames are captured and enhanced from the videotape with an image analyzer. The vertical rise of a bubble through the porous medium displays a linear dependence on time. This is the first study to quantify the terminal velocity of an air bubble rising in a stationary porous medium. Comparison is made to experimental data on air bubbles in water and Soltrol obtained using the same video photography and image analysis techniques. Although a porous medium is sometimes represented as a bundle of capillary tubes, an air bubble rising in a granular porous medium is shown to exhibit significantly different behavior from a bubble rising in either a capillary tube or a tube with a diameter comparable to the equivalent diameter of the bubble. The effect of a bubble chain, a series of single bubbles separated vertically from each other by a few centimeters, on air bubble migration in a granular porous medium is also discussed.

A mathematical model was developed to simulate the transport and dissolution of colloidal particles with a water-soluble component in a porous medium. The model is based on mass balance equations describing the mass transport, dissolution, sorption, capture, and release of colloids in a three-phase medium consisting of a solid matrix, an aqueous phase, and colloids. Colloid dissolution, contaminant sorption on solid matrix, and colloid capture mechanisms are represented by first-order kinetics. A numerical comparison of the model of a water-soluble component associated with fly ash-mobilized transport and transport due only to dissolved component migration indicates that the presence of colloids significantly increases the aqueous phase contaminant concentration.

The ignition sparks provided by the classical spark plug do not always assure a fast and complete combustion of the mixture hydrocarbon-air. For this reason we propose a new type of plug with a double spark using two simultaneous discharges generated by a pulsed high voltage power supply. This work presents the spectroscopic analysis of the plasma generated by the classic plug and the proposed plug in different positions in the space between the electrodes. These are supplied with waveforms containing one pulse by period. The waveform has adjustable pulse duration. The experiments have been done in air at atmospheric pressure. In each case it was pursued to identify the species (molecules and atoms) of spectrum in order to study the influence they may have on the development of the combustion. Because the spectra obtained are clear, stable and repeatable, it was possible to determine the temperatures in the plasma column by using two different spectroscopic diagnostic methods based on the molecular band spectra.

The electric discharge generated between the electrodes of a classic spark plug could not assure a fast and total combustion of the air -hydrocarbon mixture. To be able to improve the quality of the combustion process through the ignition system improvement it is necessary to have a complete diagnostic of the discharge produced by a spark plug, from physical and chemical point of view. This work presents a comparative study of the reduced electric field and the vibrational temperature for a classic spark produced in air at atmospheric pressure, as functions of pulses widths applied by the power supply. The reduced electric field was calculated by using the rotational temperature values established by a previous study, considering them as temperature plasma gas temperatures. The vibrational temperature was determined by using the N2second positive molecular emission spectra. The spark plug was supplied with trains of pulses containing one or two pulses having variable widths provided by a special power supply. The results obtained for the vibrational temperature of nitrogen molecules are close to these obtained for the rotational temperature calculated by using a spectroscopic diagnostic method based on the OH UV molecular band spectra (between 2000 and 3500 K). The electron temperature values, imposed by the reduced electric field (up to 2000 Td), are superior to 10000 K.

The electric discharge generated between the electrodes of a classic spark plug could not assure a fast and total combustion of the air -hydrocarbon mixture. To be able to improve the quality of the combustion process through the ignition system improvement it is necessary to have a complete diagnostic of the discharge produced by a spark plug, from physical and chemical point of view. This work presents a comparative study of the reduced electric field and the vibrational temperature for a classic spark produced in air at atmospheric pressure, as functions of pulses widths applied by the power supply. The reduced electric field was calculated by using the rotational temperature values established by a previous study, considering them as temperature plasma gas temperatures. The vibrational temperature was determined by using the N2second positive molecular emission spectra. The spark plug was supplied with trains of pulses containing one or two pulses having variable widths provided by a special power supply. The results obtained for the vibrational temperature of nitrogen molecules are close to these obtained for the rotational temperature calculated by using a spectroscopic diagnostic method based on the OH UV molecular band spectra (between 2000 and 3500 K). The electron temperature values, imposed by the reduced electric field (up to 2000 Td), are superior to 10000 K.

The - Direct Contact Membrane Distillation (DCMD) is modeled using the conjugate heat transfer Navies-stokes flow model. A uniform salty and relatively hot feed and colder fresh permeate flow are driven by the peristaltic pump are considered in parallel configuration across the membrane. Depending on the membrane parameters (permeability, thickness, pour size, and conductivity) the resulted temperature difference leads to a pressure gradient responsible for the vaporizing fraction of the feed and transport to the permeate side through the hydrophobic membrane. Under different flow conditions and membrane conductivity mass flux, heat flux, temperature polarization, and thermal efficiency are evaluated. Results showed a good agreement with the published theoretical work on the mass flow this followed with sensitivity study to two parameters one is operational and the other is designed to gain a better understanding of the system performance and metrics including temperature polarizati...

Numerical simulations of the flow field and heat transfer of squealer blade tip are performed in this study. The effects of the Reynolds number, the clearance gap to width ratios (C/W = 5%-15%) and the cavity depth to width ratios (D/W = 10%-50%) on fluid flow and heat transfer characteristics are obtained. The temperature and velocity distributions inside the cavity, the local heat transfer coefficients, and the average Nusselt numbers for the pressure and suction sides of the turbine blade tip are determined. This paper presents the results of the effects of Reynolds number, clearance gap and width ratios on the Nusslet number for the pressure and suction sides of squealer turbine blade tip. The results show a good agreement with the experimental data obtained by Metzger and Bunker. New correlations for the average Nusselt numbers for turbine blade tip pressure and suction sides are presented. INTRODUCTION Turbine blade tips are subject to higher temperature gases and higher aero ...

A superhydrophobic Zn surface was prepared by the following facile approach. First, a simple method, water-only hydrothermal oxidation, was employed to fabricate loose-stacked ZnO nanorods with hexagonal cross-sections, resulting in a superhydrophilic Zn surface. Then the superhydrophilic Zn was modified with a low-surface-energy compound, changing the surface character from superhydrophilicity to superhydrophobicity. The superhydrophobic surface reduced the Zn corrosion rate to about one-eighth of that with an untreated surface. Such effective impact on corrosion resistance could be attributed to the obstructive effect and capillary effect caused by the surface superhydrophobicity.

Low-density wood, sesenduk (Endospermum diadenum) has great a potential to substitute commercial timber, if its properties can be improved. One of the potential processes to enhance the properties of this timber is through bulking treatment with phenolic resin and rendered them insoluble in the wood. The objective of this study was to enhance the properties of sesenduk wood through bulking treatment with low molecular weight phenol formaldehyde (LmwPF, M w = 600). The effect of initial moisture content (MC), duration of soaking in the treating solution and incorporating urea in the PF resin on the properties and formaldehyde emission of the treated wood were investigated. Wood strips of dimension 10mm x 50mm x 150mm (impreg) and 20mm x 50mm x 150 mm (compreg) with initial MC of 15, 25 and >40% were

To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g−1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g−1.

Industrial production of low-charge microfibrillated cellulose (MFC) typically results in wide fibril size distributions. This polydispersity influences viscosity, overall colloidal stability, and rheological properties of MFC suspensions and gels in aqueous systems. In this work, a systematic rheological analysis is performed for industrially prepared MFC and fractions of different size distributions. Gel formation and flow characteristics (e.g., shear-thinning) of each fraction are examined under neutral and acidic conditions and compared with the unfractionated MFC suspension. The effects of size, aspect ratio, and surface charge on the rheology of semi-dilute MFC suspensions are discussed. The results The online version of this article () contains supplementary material, which is available to authorized users.

Industrial production of low-charge microfibrillated cellulose (MFC) typically results in wide fibril size distributions. This polydispersity influences viscosity, overall colloidal stability, and rheological properties of MFC suspensions and gels in aqueous systems. In this work, a systematic rheological analysis is performed for industrially prepared MFC and fractions of different size distributions. Gel formation and flow characteristics (e.g., shear-thinning) of each fraction are examined under neutral and acidic conditions and compared with the unfractionated MFC suspension. The effects of size, aspect ratio, and surface charge on the rheology of semi-dilute MFC suspensions are discussed. The results demonstrate that particle size and aspect ratio distribution control the viscoelasticity and shear-thinning properties of MFC suspensions. An increased fraction of small diameter nanofibrils, by ex situ addition of the fine particles with high aspect ratio or removal of the coarses...

For the successful commercialisation of microfibrillated cellulose (MFC) it is of utmost importance to carefully characterise the constituent cellulose particles. This could for instance lead to the development of MFC grades with size distributions tailored for specific applications. Characterization of MFC is challenging due to the heterogeneous chemical and structural nature of MFC. This study describes a fractionation approach that combines two steps of physical sieving of larger particles and a final centrifugation step to separate out the smallest, colloidally stable particles, resulting in four distinctly different size fractions. The properties, such as size and charge, of each fraction were studied, as well as MFC filtration time, film formation, and film properties (mechanical and optical). It was found that

separately. It was more challenging to dewater MFC with a higher degree of fibrillation using conventional filtration due to a greater surface area being subjected to the liquid flow. The opposite was found when using an electric field alone: the more fibrillated material has a higher surface charge and thereby is impacted more by the electric field. A combination of pressure and electric field resulted in a greatly improved dewatering rate, but no significant difference could be observed between the two qualities. After dewatering, the water retention value was slightly decreased, but the material still showed a gel-like behaviour, although the network strength was slightly reduced, as seen by a reduction in yield stress, storage and loss moduli. This was plausibly due to a decrease in the surface area and/or deformed network.

The last half-century, Dentistry has experienced a rebirth -with emergence of new polymeric materials -polymer cements (1960-70's) and late photopolymers (1980-90`s). Many other polymer matrices, (polyepoxides etc), were not considered then. Meanwhile, polyepoxides has unique restorative potential no only in engineering but medicine (prosthetics, gluing, etc.).

Background: The technological developments for nanocellulose production from cheaper plant materials compared to wood, in particular, agricultural waste is an urgent task of nanobiophysics. The discovery of possibility of expanding the functional characteristics of materials in compositions with modified cellulose particles essentially stimulated the interest of researchers in cellulose composites. Surface modification of cellulose particles by functional materials, such as dyes, metal oxides, silicon, allows applying composites with modified cellulose in various areas of modern industry. A significant improvement in the operational performances of functionalized cellulose particles can be achieved by using them as filler in polymers. Epoxy resin compositions with modified and unmodified cellulose particles, studied in present work, are an example of hybrid biosystem. The interfacial interaction of filler particles with the epoxy matrix, their concentration and dispersion can change...

Fumed silica (FS) is widely used in numerous fields of application, the plastics industry being one of the most significance, where FS has proved to be successful as an efficient thickening, thixotropic, and anti-settling agent, as well as reinforcing filler. Chemical modification of silica surface enlarges its functional capabilities. In particular, silica with grafted silicon hydride groups was found to be active in the processes of hydrosilylation of alkene and alkyne bonds in monomers during their polymerization, resulting in the formation of reinforced polymeric composites. Recently, specific epoxy resins have gained significance, and FS was found to be useful, particularly as rheological additive. The aim of this study was to evaluate the efficiency of hydride-silylated FS (HFS) as a potentially active reinforcing component for epoxy-based polymers. The activation energy for hydrosilylation of olefins is higher than that for ring-opening polymerization of epoxides, therefore, ...

The effect of chemical structure of segmented poly(urethane-urea)s on its interfacial interactions with poly(vinyl chloride) as well as supramolecular structure and the properties of prepared composites has been studied. A direct influence of flexible and rigid segments of elastomers on a compatibility, structure and the physical-mechanical properties of poly(urethane-urea)/poly(vinyl chloride) blends was investigated. A formation of intermolecular hydrogen bonds network in the poly(urethane-urea)/poly(vinyl chloride) systems was evaluated by FTIR analysis. Morphology studies have shown the effect of interfacial interactions on a size of thermoplastic phase dispersed within elastomer matrix. Obtained poly(urethane-urea)/poly(vinyl chloride) micro-and nanocomposites have improved tensile properties.

It was found that UV irradiation of a composition based on an oligoether acrylate binder and Aerosil filler gives rise to at least two types of free radicals. The presence of the filler slowed down the decay of radicals in the irradiated composition. In the completely polymerized composite, the total amount of radicals depends on the specific surface area and Aerosil concentration. The radical decay is the most intense during the first 24 h after irradiation; then the process is strongly decelerated.

Tungsten trioksida (WO 3 ) merupakan salah satu fotomangkin yang berpotensi dalam aplikasi penjanaan gas hidrogen daripada tindak balas pembelahan air. Dalam kajian ini, pelbagai komposisi filem nipis WO 3 terdop nikel dihasilkan pada kaca stanum(IV) oksida terdop fluorin (FTO) dengan menggunakan asid tungstik dan nikel(II) asetat sebagai bahan pemula. Selepas disepuhlindap pada 500°C selama 30 min, sampel filem nipis ini dicirikan dengan menggunakan SEM, XRD, spektrofotometer UV-Vis serta analisis fotoelektrokimia (PEC). WO 3 terdop nikel mempunyai saiz zarah yang lebih besar berbanding sampel WO 3 tulen dan mempunyai struktur hablur monoklinik. Jurang tenaga WO 3 terdop nikel yang dianggarkan daripada spektrum UV-Vis dengan menggunakan formula Tauc adalah lebih kecil berbanding jurang tenaga bagi WO 3 tulen. Ujian aplikasi PEC di bawah sinaran lampu xenon menunjukkan kecekapan penghasilan gas hidrogen oleh filem WO 3 terdop nikel yang digunakan sebagai fotoanod telah dipertingkatkan.

A benzoylthiourea molecule namely 1,1-dibenzyl-3-(2-bromobenzoyl)thiourea ( ) was synthesized and characterized by C, H, N and S elemental, mass spectrometry and spectroscopic analyses (infrared, ultraviolet-visible and nuclear magnetic resonance). The 2BrBT compound crystallized in a tetragonal system with the space group P4 3 and exhibits an acentric crystalline packing due to the presence of intermolecular H-bonding network that forms a self-assembly of 1D helical motif. The asymmetric delocalisation of electrons in the molecule retains its transparency throughout the visible and near-infrared region and hence, essentially propagates the macroscopic helical motif in the solid state. The highest-occupied and lowest-unoccupied molecular orbital (HOMO/LUMO) are mainly found on the thiourea moiety and the benzoylthiourea fragment, respectively and shows an optical bandgap of 3.50 eV. The influence of its geometrical characteristics to the optical properties of 2BrBT is established and discussed in view of nonlinear optical (NLO) application.

This study aimed to synthesize and characterize cobalt sulfide deposited on FTO by hydrothermal method and investigate its photoelectrochemical (PEC) water splitting performance. Cobalt sulfide thin films were produced by annealing at two different temperatures, namely, 400 and 500 °C. X-ray diffraction (XRD) and Fourier transform Raman spectroscopy were used to characterize the phase structure. Scanning electron microscopy was used to observe the morphology. Ultraviolet-visible spectroscopy and linear sweep voltammetry analyses were used to determine the thin-film band gap and evaluate the PEC water splitting performance, respectively. From the XRD and Raman analyses, all the samples produced consisted of mixed phases of Co3S4 and Co9S8. However, each sample contained different percentage phases. The sample annealed at 400 °C contained more Co9S8, whereas that annealed at 500 °C contained comparable amounts of Co3S4 and Co9S8. The morphologies of pre-annealed samples showed vertica...

Photoelectrochemical (PEC) water splitting is a very promising green method to produce solar fuel. Titanium dioxide (TiO2) has been widely used as photocatalyst for this type of reaction. Improving the performance of TiO2 for PEC water splitting has been ongoing and addition of sacrificial donor especially from waste is an attractive option to achieve this. Oxalic acid is one component in organic waste stream that can be used as sacrificial donor. The TiO2 thin films has been fabricated by coating TiO2 paste on Fluorine Tin oxide (FTO) glass surface. The morphology of the TiO2 thin films were porous and rough with uniform particles size with crystallite size of about 20 nm and dominant anatase peak. The TiO2 photoelectrode undergo PEC testing to measure its photolectroactivity by using oxalic acid as a sacrificial donor in two different type of electrolytes which are distilled water and sodium sulfate (NA2SO4) aqueous solution. The photocurrent produced without addition of oxalic ac...

The Re(I) complex, [Re(PyPzH) (CO) 3 Cl] where pyridine, was successfully synthesised and characterised with an infrared (IR), ultraviolet-visible (UV-Vis), 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopies and X-ray crystallography. The IR spectrum featured three n(C≡O), n(N-H), n(C=N) and n(C=C) signals at (1860-2020), 3137, 1614 and 1513 cm -1 , respectively. The UV-Vis spectrum of the complex exhibited ligand-centred (π®>*) electronic excitations [λ max = 227 nm, ε = 1.942 x 10 4 M -1 cm -1 ; l max = 292 nm, ε = 0.853 x 10 4 M -1 cm -1 ] and a metal-to-ligand charge transfer (MLCT) band [l max = 331 nm, ε = 0.467 x 10 4 M -1 cm -1 ]. The 13 C and 1 H-NMR spectra exhibited the characteristic signals of the three C≡O (189.0 -199.0 ppm) and NH (14.84 ppm), respectively. The X-ray structure of [Re(PyPzH)(CO) 3 Cl] showed the crystal adopted a monoclinic system with a C2/c space group [unit cell dimensions: a = 27.7422( ) Å, b = 11.1456(5) Å, c = 9.2461(4) Å with α = γ = 90º and β = 92.552(2)º]. Density functional theory (DFT) and time-dependent (TD) DFT calculations were performed to investigate the optimised structural geometry and electronic properties of the title complex. The results showed that the highest-occupied molecular orbital (HOMO) was predominantly found on the dπ-orbitals of Re(I), Cl and CO. While the lowest-unoccupied molecular orbital (LUMO) was located on the PyPzH moiety. The structural and photophysical properties of the [Re(PyPzH)(CO) 3 Cl] were established and the reaction enthalpies for the dissociation of Cl atom in the formation of [Re(PyPzH)(CO) 3 ] • were discussed in view of its potential application for photocatalytic CO 2 reduction.

This paper describes the development of a lidar transmitter using an optical parametric amplifier. It is designed for profiling gases of atmospheric interest at high spatial and temporal precision in the near-IR. Discussions on desirable characteristics for such a transmitter with specific reference to the case of CO, are made.

Al assembly prepared by absolute wet chemical methods including chemical bath deposition (CBD), successive ionic layer adsorption and reaction (SILAR) and spin coating has been studied to investigate the effect of thickness of active PANI layer on device performance. Structural, morphological and chemical bond features have been investigated by using X-ray diffraction, Field Emission Scanning Electron Microscopy and Fourier Transform Infrared spectroscopy of the layers and are discussed herein. Effect of PANI thickness on current-voltage characteristic has been studied under dark and illumination (100 mW/cm 2 , AM 1.5G, 1 Sun) condition to know the solar cell performance.

Controlled growth of different sizes of cadmium selenide (CdSe) nanoparticles over well aligned ZnO nanorods have been performed using successive ionic layer adsorption and reaction (SILAR) technique at room temperature (27 o C) in order to form nano heterostructure solar cells. Deposition of compact layer of zinc oxide (ZnO) by SILAR technique on fluorine doped tin oxide (FTO) coated glass substrate followed by growth of vertically aligned ZnO nanorods array using chemical bath deposition (CBD) at low temperature (<100 o C). Different characterization techniques viz. X-ray diffractometer, UV-Vis spectrophotometer, field emission scanning electron microscopy and X-ray photoelectron spectroscopy have been used to know the structural, optical, morphological and compositional properties of synthesized nano heterostructure. The photovoltaic performance of the cells with variation in SILAR cycles for CdSe and with use of different electrolytes have been recorded as J-V characteristics and the maximum conversion efficiency of 0.63% have been attained with ferro/ferri cyanide electrolyte for 12 cycles CdSe coating over 1-D ZnO nanorods.

Efforts have been put forth to grow HgS with cauliflower like surface architecture through simple and lowcost successive ionic layer adsorption and reaction (SILAR) method at room temperature for supercapacitive electrode application. Such a unique morphology facilitates the electrolyte ions to penetrate during electrochemical activities. Maximum specific capacitance of 446 F/g was obtained in cyclic voltammetry measurement at 2 mV/s scan rate in 1 M KCl electrolyte. After initial drop of capacitance up to 500 cycles, reduction was relatively slow up to 2000 cycles during stability analysis. Most importantly, the revealed specific energy of 15.45 Wh/kg of electrode has promised as decent electrode in energy storage field for future scope.

Chemical vapor deposited free-standing flexible MWCNTs bucky paper towards extremely stable and energy efficient supercapacitive electrode and aqueous symmetric supercapacitor (ASSC) device application Highlights  Flexible and free-standing multi-walled carbon nanotubes (MWCNTs) bucky paper was synthesized by chemical vapor deposition (CVD).  Highest specific capacitance of 270 F/g was obtained with superb stable behavior (88 % at 10,000 cycles) in liquid-state electrode configuration.  Complete aqueous symmetric supercapacitor (ASSC) device was fabricated with a wide potential window of 1.6 V.  Extraordinary specific capacitance (91 F/g at scan rate of 2 mV/s), specific energy (32 Wh/kg), and capacitive retention (107 % after 6000 cycles) indicates the excellent electrochemical performance of the device.  The device showed practical applicability by lighting up a red LED for 20 s.

A simple and scalable approach has been reported for V2O5 encapsulation over interconnected multi-walled carbon nanotubes (MWCNTs) network using chemical bath deposition method. Chemically synthesized V2O5/MWCNTs electrode exhibited excellent charge-discharge capability with extraordinary cycling retention of 93% over 4000 cycles in liquid-electrolyte. Electrochemical investigations have been performed to evaluate the origin of capacitive behavior from dual contribution of surface-controlled and diffusion-controlled charge components. Furthermore, a complete flexible solid-state, flexible symmetric supercapacitor (FSS-SSC) device was assembled with V2O5/MWCNTs electrodes which yield remarkable values of specific power and energy densities along with enhanced cyclic stability over liquid configuration. As a practical demonstration, the constructed device was used to lit the &#39;VNIT&#39; acronym assembled using 21 LED&#39;s.