EFFECT OF DISSOLVED SODIUM CHLORIDE SALT ON THE LIQUID-LIQUID EQUILIBRIA OF THE TERNARY SYSTEM ISOPROPYL ETHER-ACETIC ACID-WATER

The effect of the addition of the salt sodium chloride on the liquid-liquid equilibrium data of the ternary system isopropyl ether-acetic acid-water has been experimentally investigated at 30°C. Both the solubility (bimodal) curve and the tie-line have been determined for three salt concentrations. The addition of sodium chloride salt enhances the distribution of acetic acid in ether layer. The tie-line data have been correlated by Othmer and Tobias and Hand plots. The ternary solubility and tie-line data at 30°C for this system in the absence of salt have also been experimentally obtained in this work.     

Sharpening ofE-plane radiation patterns ofE-plane sectoral horns by metallic grills

Results of an exhaustive experimental study of the effect of conducting grills on theE-plane radiation patterns ofE-plane sectoral horns are presented. It is observed that the grills satisfying certain optimum conditions are capable of focusing the patterns with considerable improvement in beamwidth and directive gain. The impedance conditions are also improved by the presence of the grills. Data for a number of horns operating at a wide range of frequencies are presented.     

Simple dipstick cryostat with versatile temperature controller for high thermal stability

A simple dipstick type vapour cryostat and a versatile electronic temperature controller which uses a proportional, integral and differential type of control are described. They have been used together for the calibration of thermometers in the liquid helium temperature range and for the measurement of the transition temperature of superconductors. Temperature stability of 2 mK (typical) is achieved easily at a working temperature of 7 K for a period exceeding an hour. The use of the system is quite general and can readily cover the temperature range up to 300 K with a suitable choice of temperature sensor and heat input.     

Web Server Performance Modeling

The advent of Web technology has made Web servers core elements of future communication networks. Although the amount of traffic that Web servers must handle has grown explosively during the last decade, the performance limitations and the proper tuning of Web servers are still not well understood. In this paper we present an end-to-end queueing model for the performance of Web servers, encompassing the impacts of client workload characteristics, server harware/software configuration, communication protocols, and interconnect topologies. The model has been implemented in a simulation tool, and performance predictions based on the model are shown to match very well with the performance of a Web server in a test lab environment. The simulation tool forms an excellent basis for development of a Decision Support System for the configuration tuning and sizing of Web servers.     

Time tick based method for measuring static errors of ADC

This paper presents a novel Time Tick based Built In Self Test (TT BIST) for measuring the static errors of an Analog to Digital Converter (ADC). The proposed method determines the period elapsed during transition between two consecutive digital levels and compares it with the ideal period of transition. A counter that works, at higher speed relative to the sampling rate of the ADC under test, is used. It counts the number of time ticks occurred during every transition. The required ramp signal is generated dynamically, using current source with digital switch for selecting the equivalent test signal. Further to support testing of errors in ratiometric ADC, a slope conditioning module is also implemented. The entire computation cycle is done in a single ramp cycle whereas in conventional histogram method multiple waveforms are required. Thus, the proposed TT method requires less time to achieve desired accuracy levels by choosing the appropriate slope of the ramp signal.     

Determination of Anisotropic Yield Coefficients by a Data-Driven Multiobjective Evolutionary and Genetic Algorithm

The texture induced anisotropy of yield strength in cold rolled sheet metals is modeled using anisotropic yield criteria. The classical and other optimization methods used so far to determine the yield coefficients are limited by fixed set of experimental data, initial guess values, and pre-determined weight factors. A robust multiobjective optimization based on evolutionary algorithm proposed in this paper minimizes the error in yield stress and plastic strain ratio simultaneously and thereby overcomes the limitations in the approaches used before. The new approach is tested using Hill48 and Barlat89 yield criteria for five different materials from literature. The new approach is observed to improve the prediction capability of yield coefficients when compared to earlier approaches. The Pareto frontier obtained in the new approach can serve as a comparative tool to evaluate the accuracy of different yield criteria.     

Automated texture‐based characterization of fibrosis and carcinoma using low‐dose lung CT images

Lung cancer is the most common cause of cancer deaths worldwide and account for 1.38 million deaths per year. Patients with lung cancer are often misdiagnosed as pulmonary tuberculosis (TB) leading to delay in the correct diagnosis as well as exposure to inappropriate medication. The diagnosis of TB and lung cancer can be difficult as symptoms of both diseases are similar in computed tomography (CT) images. However, treating TB leads to inflammatory fibrosis in some of the patients. There comes the need of an efficient computer aided diagnosis (CAD) of the fibrosis and carcinoma diseases. To design a fully automated CAD for characterizing fibrous and carcinoma tissues without human intervention using lung CT images. The 18 subjects in this study include seven healthy, two fibrosis and eight carcinoma, and one necrosis cases. The dataset is built by CT cuts representing healthy is 113, fibrosis is 103, necrosis is 39, and carcinoma is 185 totalling 440 images. The gray‐level spatial dependence matrix and gray level run length matrix approach are used for extracting texture‐based features. These features are given to neural network classifier and statistical classifier. These classifier performances are evaluated using receiver‐operating characteristics (ROC). The proposed method characterizes these tissues without human intervention. Sensitivity, specificity, precision, and accuracy followed by ROC curves were obtained and also studied. Thus, the proposed automated image‐based classifier could act as a precursor to histopathological analysis, thereby creating a way to class specific treatment procedures.     

Mercury centres in caesium halide crystals

Electronic absorption spectrum of CsBr crystals doped with Hg²⁺ showed three bands at 340, 250 and 217.5 nm at 300 K, which disappeared on ageing and reappeared on quenching the crystals from 700 K. Radiation damage studies indicated the formation of Hg²⁺ centres and on prolonged irradiation Hg²⁺ centres. Similar results have also been obtained in the case of Csl: Hg²⁺.