Synthesis of tellurium containing syndiotactic polymethyl methacrylate using diphenyl ditelluride as a novel initiator

The synthesis of syndiotactic polymethyl methacrylate containing tellurium by using diphenyl ditelluride in the dioxan at (60 ± 0.1)°C for 2 h has been carried out. The presence of tellurium in the polymer has been confirmed qualitatively as well as by induced coupled plasma mass spectroscopy (ICP‐MS). The electron spin resonance spectrum shows the presence of T?Ph, and value of gyromagnetic constant g has been calculated as 2.2203. The T_g of the polymer, measured by DSC, is 105°C. The syndiotactic nature has been confirmed by FTIR and NMR spectroscopy and DSC. The system follows ideal kinetics with activation energy 66 kJ mol^?1. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1017–1022, 2006     

Analysis and evaluation of operating variables for the yield of Karanja and neem oil-based biodiesel production

The aim of this research is to present the possibilities of the use of non-edible oils in biodiesel production, to consider the various methods for treatment of non-edible oils and to emphasise the influence of the operating and reaction conditions on the process rate and the ester yield. Because of biodegradability and non-toxicity biodiesel has become more attractive as alternative fuel. Biodiesel is produced mainly from vegetable oils by transesterification. For economic and social reasons, edible oils should be replaced by lower-cost and reliable feedstock for biodiesel production, such as non-edible plant oils. In this work biodiesel is produced from neem and Karanja by using butanol, propanol, ethanol and methanol as alcohols and KOH and NaOH as alkali catalysts by the transesterification process. The aim of this research is to analyse the different reaction parameters such as catalyst concentration, type of catalyst, types of alcohol, alcohol to oil molar ratio, reaction time and reaction temperature on the yield of biodiesel from non-edible oils. The maximum yield obtained was 95% with Karanja as oil with methanol and KOH as alkali catalyst at oil to alcohol molar ratio of 6:1 in 1 h at 60°C. Special attention is paid to the possibilities of producing biodiesel from non-edible oils.     

Analysis and design of low power SRAM cell using independent gate FinFET

Scaling of bulk MOSFET faces great challenges in nanoscale integration technology by producing short channel effect which leads to increased leakage. FinFET has become the most promising substitute to bulk CMOS technology because of reducing short channel effect. Dual-gate FinFET can be designed either by shorting gates on either side for better performance or both gates can be controlled independently to reduce the leakage and hence power consumption. A six transistor SRAM cell based on independent-gate FinFET technology is described in this paper for simultaneously reducing the active and standby mode power consumption. A work is focused on the independent gate FinFET technology as this mode provides less power consumption, less area consumption and low delay as compared to other modes. Leakage current and power consumption in independent gate FinFET is compared with tied gate or shorted gate FinFET SRAM cell. Moreover, delay has been estimated in presented SRAM cells. Further, leakage reduction technique is applied to independent gate FinFET 6T SRAM cell.     

Artificial Neural Networks as a Valuable Tool for Well Log Interpretation

Abstract

Artificial neural networks (ANNs) are rapidly gaining popularity in the area of oil exploration. This article discusses the importance of ANNs to petroleum engineers and geoscientists and its advantages over other conventional methods of computing. ANNs can assist geoscientists in solving some fundamental problems such as formation, permeability prediction, and well data interpretation from geophysical well log responses with a greater degree of confidence comparable to actual well test interpretation.

The main goal of the present article is to use the artificial neural network from a petroleum geoscientist's point of view and encourage geoscientists and researchers to consider it as a valuable alternative tool in the petroleum industry. A three-layer feed-forward back-propagation network has been used to predict neutron log (NPHI) and density log (RHOB) values using gamma ray (CGR), resistivity log (IDPH), and sonic log (DTCO) input parameters. The results are also compared by analysis performed by multivariate regression analysis (MVRA).     

Variability aware SVM macromodel based design centering of analog circuits

Design centering is the term used for a procedure of obtaining enhanced parametric yield of a circuit despite the variations in device and design parameters. The process variability in nanometer regimes manifest into variations in these devices and design parameters. During design space exploration of analog circuits, a methodology to find design-instances with better yield is necessitated; this would ensure that the circuit will function as per specifications after fabrication, even with impact of statistical variations. We need to evaluate circuit performance for a given instance of a circuit-design identified by possessing a set of nominal values of device-design parameters. A lot of instances need be searched, having different sizes for a given circuit topology. HSPICE is very compute intensive. Instead, we employ macromodeling approach for analog circuits based on support vector machine (SVM), which enables efficient evaluation of performance of such circuits of different sizing during yield optimization loops. These performance macromodels are found to be as accurate as SPICE and at the same time, time-efficient for use in sizing of analog circuits with optimal yield. Process variability aware SVM macromodels are first trained and then used inside the Genetic algorithm loops for design centering of different circuits, subsequently resulting into sized-circuit instances having optimal yield. Post design centering, the sized circuits will be able to provide functions as per specifications upon fabrication. The application of this design centering approach as process variability analysis tool is illustrated on various circuits e.g. two stage op amp, voltage controlled oscillator and mixer circuit with layouts drawn into 90?nm UMC technology (Euro-practice).     

Active Antenna Module for Low-Cost Electronically Scanned Phased Arrays

This paper describes a low-cost compact active antenna module that includes transmit/receive/mixer electronics and a dual-polarized antenna element for half-duplex operation at 10 GHz. The system-in-package module has been fabricated in a ball-grid-array package. It is particularly suited for large low-cost low-power phased-array applications. Measurements at IF of single element gain show cross-pol reduced 18 dB. A small compact array was fabricated and measured. Simulations show that coupling between modules in a tightly packed infinite array caused a small reduction in scan range.     

Failure resistant topology optimization of structures using nonlocal elastoplastic-damage model

For energy absorbing structures made up of ductile materials, the plastic strain accumulation often leads to early material damage and failure, which can deteriorate the overall structural performance. The goal of this work is to limit this damage in elastoplastic designs using the density-based topology optimization framework such that the optimized structures can absorb energy in a more controllable manner. To this end, an implicit nonlocal coupled elastoplastic damage model is considered for simulating the material damage and softening behavior. The nonlocal effect from the void elements is removed by introducing a scaling scheme for the nonlocal parameters. Path-dependent sensitivity is derived analytically using an adjoint method whose accuracy is further verified by the central difference method. The effectiveness of the proposed method is demonstrated through several numerical examples. It is shown that the load-carrying capacity, ductility, as well as ultimate plastic work dissipation capacity of the optimized design, can be considerably improved by the proposed method.