Comparative Study on the Properties of Galvanically Deposited Nano- and Microcrystalline Thin Films of PbSe

Thin films of PbSe having both nano- and microstructures have been deposited on transparent conducting oxide (TCO)-coated glass substrates electrochemically, from an aqueous solution of Pb(OAc)₂, ethylenediamine tetraacetic acid (EDTA), and SeO₂. A Pb strip acted as the sacrificial anode, while the TCO glass was the cathode. No external bias was applied. The formation of PbSe was pH sensitive, and pH ~3 was found to be optimum for film deposition. Films grown at room temperature (25°C) were nanocrystalline (~25 nm), while those deposited at 80°C were microcrystalline (~150 nm). Films were characterized by x-ray diffraction studies, field-emission scanning electron microscope image analysis, infrared spectral analysis, and by both alternating-current (a.c.) and direct-current (d.c.) electrical measurements. A blue-shift was observed for the nanocrystalline films. Film resistivity and junction properties were obtained from electrical measurements.     

Microstructure and growth of ZnTe films

The microstructure and growth of ZnTe films deposited onto glass and freshly cleaved NaCl substrates are carefully studied by a TEM. Effect of different stimulator on the grain growth is also described.     

The differential induction machine: Theory and performance

This paper presents the theory and performance of a differential induction machine, which is a special type of induction machine having two shafts projected from the two ends of a single stator. Application of a differential load on the two shafts cause them to run at different speed as a motor, which permits true differential movement and thus can meet the requirements of a differential drive in an electric vehicle. The machine is also capable of regeneration in the differential mode. This paper presents the construction of the above machine and performance of the same based on experimental results from a laboratory prototype. The equivalent circuit of the motor has been presented and verified experimentally.     

Synthesis of flexible polymeric shielding materials for soft gamma rays: Physicomechanical and attenuation characteristics of radiation crosslinked polydimethylsiloxane/Bi2O3 composites

Flexible lead‐free high energy radiation shielding material was developed through internal compounding. Polymer‐filler interaction, crosslinking density, specific gravity, physicomechanical characteristics, percentage attenuation, and thermal stability of the crosslinked composites were estimated. It was found that even at very high filler loading composites can be crosslinked; however, the crosslinking density was composition dependent and was highest in 10–50 wt% loading range at 100 kGy and 200 kGy. The Nielsen model was applied to understand the micromechanics of the system. Attenuation of gamma radiation from Am241 was not affected by the crosslinking density. Thermal stability of the composites was found to be significantly affected with bismuth oxide loading. POLYM. COMPOS., 37:756–762, 2016. © 2014 Society of Plastics Engineers     

Synthesis of cross-linked graft copolymer from [2-(methacryloyloxy)ethyl] trimethylammonium chloride and poly(vinyl alcohol) for removing chromium(VI) from aqueous solution

A novel graft copolymer of [2-(methacryloyloxy)ethyl] trimethylammonium chloride onto poly(vinyl alcohol) has been synthesized and it is cross-linked by glutaraldehyde for the investigation of its efficiency in removing Cr(VI) from aqueous solution. The chemical nature of the ion-exchange resin has been elucidated with the help of chemical test, Fourier transform infrared, thermo gravimetric analysis and DTA. Particle size, surface area, ion-exchange capacity, optimum pH, reaction time and temperature for Cr(VI) extraction were determined. Chromium(VI) adsorption kinetics, isotherm and thermodynamics have been studied. A plausible mechanism for chromium ion-exchange has been suggested.     

Ru(II)–CO complexes of thioarylazoimidazoles: Syntheses,structures, spectroscopy and DFT calculation

The complexes, cis-(CO)-trans-(Cl)-[Ru(SRaaiNR)(CO)₂Cl₂] (2) and trans-(Cl)-[Ru(SRaaiNR)(CO)Cl₂] (3) (SRaaiNR = 1-alkyl-2-{(o-thioalkyl)phenylazo}imidazoles; R = Me (1a) and Et (1b)) have been synthesized and characterized. The structural confirmation is achieved by single crystal X-ray structure determinations. The complexes show Ru(III)/Ru(II) couple and ligand reductions. Electronic structure and spectral properties of the complexes have been explained with the DFT and TDDFT calculation.     

Risk-Based Evaluation for Meeting Future Water Demand of the Brahmaputra Floodplain Within Bangladesh

A risk-based evaluation is performed for meeting future water demands in the Brahmaputra Floodplain Area within Bangladesh (BFA). This evaluation is carried out using three risk-based performance indicators: reliability, resiliency and vulnerability. The vulnerability indicator has been redefined incorporating the aspect of a supply failure. The analysis includes the impacts of climate change on both water demands and resources, and the generation of synthetic flows of the Brahmaputra River using time series models. The simulated values of the indicators reveal that the expected demand of the BFA up to the year 2050 can be supplied with the proposed Brahmaputra Barrage inside Bangladesh under the ‘no change’ in climatic condition, provided that the groundwater remains usable. However, if groundwater becomes unusable due to widespread arsenic contamination and/or a climate change occurs, it would not be possible to meet the future water demand of the region with high reliability, moderate resiliency and low vulnerability.     

Application of artificial neural network for the prediction of laser cladding process characteristics at Taguchi-based optimized condition

This paper presents an investigation on the optimization of multiple performance characteristics during CO₂ laser cladding process considering clad width and clad depth as performance characteristics. This optimization for multiple quality characteristics has been done using Taguchi’s quality loss function. The process model for laser cladding operation using various techniques like artificial neural network (ANN) has rarely been found in the literature review. In the present work, a number of experiments have been performed to establish the interrelationship between process variables and response variables using the back propagation method of ANN. The essential input process parameters are identified as laser power, scan speed of work table, and powder feed rate. Moreover, the analysis of variance is also employed to determine the contribution of each control parameter on clad bead quality. In order to validate the predicted result, an experiment as confirmatory test is carried out at the optimized cladding condition. It is observed that the confirmatory experimental result is showing a good agreement with the predicted one. However, it has been found that the optimum condition of the cladding parameters for multi-performance characteristics varies with the different combinations of weighting factors.     

Inverse and efficiency of heat transfer convex fin with multiple nonlinearities

In this article, we first propose the novel semi‐analytical technique—modified Adomian decomposition method (MADM)—for a closed‐form solution of the nonlinear heat transfer equation of convex profile with singularity where all thermal parameters are functions of temperature. The longitudinal convex fin is subjected to different boiling regimes, which are defined by particular values of n (power index) of heat transfer coefficient. The energy balance equation of the convex fin with several temperature‐dependent properties are solved separately using the MADM and the spectral quasi‐linearization method. Using the values obtained from the direct heat transfer method, the unknown parameters of the profile, such as thermal conductivity, surface emissivity, heat generation number, conduction‐convection parameter, and radiation‐conduction parameter are inversely predicted by an inverse heat transfer analysis using the simplex search method. The effect of the measurement error and the number of measurement points has been presented. It is found that present measurement points and reconstruction of the exact temperature distribution of the convex fin are fairly in good agreement.