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Yadav S.,Indian National Institute of Foundry and Forge Technology | Srivastava V.,Indian Institute of Technology BHU Varanasi | Banerjee S.,Allahabad University | Weng C.-H.,I - Shou University | Sharma Y.C.,Indian Institute of Technology BHU Varanasi
Catena | Year: 2013

The objective of this study is to investigate the removal of Cr(VI) from aqueous solutions by using modified sand as adsorbent. The modified sand was characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and FTIR. pH zpc of the raw and modified sands was found to be 6.98 and 6.66, respectively. Removal efficiency of the modified sand was investigated by using batch adsorption experiments. The effect of important parameters such as initial concentration, contact time, adsorbent dosage, pH and temperature on removal of Cr(VI) was investigated. It was demonstrated that the removal efficiency increased from 67.24% to 80.40% by the decreasing initial metal concentration from 15 to 5mgL -1. Effect of pH was investigated by varying the solution pH from 2.0 to 8.0. The optimum pH for adsorption of Cr(VI) on modified sand was found to be 2.5 with a maximum removal of ~80.40%. Extent of removal decreases by increasing the temperature from 25°C to 35°C confirming exothermic nature. Kinetics of removal process was studied by applying pseudo-first order and pseudo-second order models. Pseudo-first order rate constant was found to be 0.037min -1 while the rate constant for pseudo-second order reaction was found to be 0.0236gmg -1min -1 at 25°C. Values of thermodynamic parameters viz. {increment}G°, {increment}H° and {increment}S° were calculated and found to be -3.67kJmol -1, -68.74kJmol -1and -0.243kJmol -1K -1, respectively at 25°C. The values of δG° were found to be negative at all temperatures indicating the spontaneity of the removal process. A negative value of {increment}H° further confirms the exothermic nature of removal process. The experimental data were fitted to Langmuir as well as Freundlich adsorption isotherm equations. The results obtained in the present study show the modified sand to be a better adsorbent for removal of Cr(VI). © 2012 Elsevier B.V. Source


Mandal S.K.,Indian National Institute of Foundry and Forge Technology | Chan F.T.S.,Hong Kong Polytechnic University | Tiwari M.K.,Indian Institute of Technology Kharagpur
Expert Systems with Applications | Year: 2012

The generation of leak along the pipeline carrying crude oils and liquid fuels results enormous financial loss to the industry and also affects the public health. Hence, the leak detection and localization problem has always been a major concern for the companies. In spite of the various techniques developed, accuracy and time involved in the prediction is still a matter of concern. In this paper, a novel leak detection scheme based on rough set theory and support vector machine (SVM) is proposed to overcome the problem of false leak detection. In this approach, 'rough set theory' is explored to reduce the length of experimental data as well as generate rules. It is embedded to enhance the decision making process. Further, SVM classifier is employed to inspect the cases that could not be detected by applied rules. For the computational training of SVM, this paper uses swarm intelligence technique: artificial bee colony (ABC) algorithm, which imitates intelligent food searching behavior of honey bees. The results of proposed leak detection scheme with ABC are compared with those obtained by using particle swarm optimization (PSO) and one of its variants, so-called enhanced particle swarm optimization (EPSO). The experimental results advocate the use of propounded method for detecting leaks with maximum accuracy. © 2011 Elsevier Ltd. All rights reserved. Source


Shrivastava A.K.,Indian National Institute of Foundry and Forge Technology
Indian Journal of Environmental Protection | Year: 2010

Zinc is one of the toxic metals which is present in air, soil, water and food. It is emitted into the environment from various industries and plants (zinc smelters, zinc plating, galvanizing, in making alloys, etc.). In the present paper, adsorption studies are carried out. Here adsorbent point of use granular activated carbon (POU-GACFC) impregnated with waste tea leaves carbon (WTLC) has been used for sorption of zinc(II) from water/wastewater. A design of treatment system for water containing zinc is shown. © 2010 - Kalpana Corporation. Source


Malapati M.,Indian National Institute of Foundry and Forge Technology | Bhattacharyya B.,Jadavpur University
Materials and Manufacturing Processes | Year: 2011

Electrochemical micromachining (EMM) appears to be very promising as a future micromachining process due to higher machining rate, better precision and control, and wide range of materials that can be machined. The present article highlights the experimental study of EMM process parameters, i.e., pulse frequency, machining voltage, duty ratio, electrolyte concentration, and micro-tool feed-rate, and their influences on micromachining criteria such as material removal rate (MRR) and machining accuracy during micro-channel generation. Scanning type strategy is considered for the movement of micro-tool during micro-channel generation Experiments are planned based on response surface methodology (RSM) and conducted on the indigenously developed EMM system setup. Empirical mathematical models of various process parameters on MRR and machining accuracy in EMM process are developed through RSM. The validity of the models is tested through analysis of variance (ANOVA). Optimal values for multiobjective optimization of the process parameters have been found out as pulse frequency of 52.2818kHz, machining voltage of 10.1033V, duty ratio of 68.3890%, electrolyte concentration of 85.1515g/l, and micro-tool feed-rate of 208.5860m/sec for the maximum MRR and improved accuracy. Response surface plots for each response are analyzed. Condition of machined micro-channels is also analyzed through scanning electron microscope (SEM) micrographs. The developed models will be very useful to find out the optimal parametric setting to produce high accuracy micro-channels utilizing scanning movement strategy of micro-tool. © 2011 Taylor & Francis Group, LLC. Source


Kumar S.R.,Indian National Institute of Foundry and Forge Technology | Nuthalapati M.,Indian National Institute of Foundry and Forge Technology | Maity J.,National Institute of Technology Durgapur
Scripta Materialia | Year: 2012

A nanocrystalline thin film of ZnSe was successfully electrodeposited on a copper substrate using a non-aqueous solution. X-ray diffraction analysis confirmed the deposition of crystalline ZnSe with a 12 nm crystallite size. Scanning electron microscopy and atomic force microscopy studies revealed a densely packed non-porous granular deposit. The Schottky diode characteristic corroborated a typical semiconducting behaviour of ZnSe deposit. The band gap (2.71 eV) obtained through spectroscopic analysis and the measured resistivity (1.5 Ω cm) were also in good agreement with the reported data of semiconducting ZnSe. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

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