Jadavpur University

About: Jadavpur University is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Population & Schiff base. The organization has 10856 authors who have published 27678 publications receiving 422069 citations. The organization is also known as: JU & Jadabpur University.

Investigation into electrochemical micromachining (EMM) through response surface methodology based approach.

Abstract: Electrochemical micromachining (EMM) could be used as one the best micromachining technique for machining electrically conducting, tough and difficult to machine material with appropriate machining parameters combination. This paper attempts to establish a comprehensive mathematical model for correlating the interactive and higher-order influences of various machining parameters, i.e. machining voltage pulse on/off ratio, machining voltage, electrolyte concentration, voltage frequency and tool vibration frequency on the predominant micromachining criteria, i.e. the material removal rate and the radial overcut through response surface methodology (RSM), utilizing relevant experimental data as obtained through experimentation. Validity and correctiveness of the developed mathematical models have also been tested through analysis of variance. Optimal combination of these predominant micromachining process parameters is obtained from these mathematical models for higher machining rate with acuuracy. Considering MRR and ROC simultaneously optimum values of predominant process parameters have been obtained as; pulse on/off ratio, 1.0, machining voltage, 3 V, electrolyte concentration, 15 g/l, voltage frequency of 42.118 Hz and tool vibration frequency as 300 Hz. The effects of various process parameters on the machining rate and radial overcut are also highlighted through different response surface graphs. Condition of machined micro-holes are also exhibited through the SEM micrographs in this paper. Pulse voltage pattern during electrochemical micromachining process has been analyzed with the help of voltage graphs. Irregularities in the nature of pulse voltage pattern during electrochemical micromachining have been observed and the causes of these irregularities are further investigated.

Recent advances in low temperature, solution processed morphology tailored ZnO nanoarchitectures for electron emission and photocatalysis applications

Abstract: Having the benefit of several features such as low cost, straightforward processing, easy fabrication, large area deposition and physical flexibility, low temperature solution processed electronic devices have gained traction in the eyes of the research community as the difficulties associated with conventional higher temperature crystalline semiconductor devices are incrementally rendering them outdated. Over the last decade, amongst metal oxides, ZnO with its rich variety of nanoforms has been documented as the candidate with the highest economic impact by virtue of its diverse use in a plethora of electronic and optoelectronic applications relying on its associated unique functional features such as high mobility, excellent thermal stability and high transparency. To date, most review articles in the literature focused on ZnO nanostructures realized via the vapour phase method whereas a comprehensive study on solution processed nanoforms and their widespread use is still lacking. The current article mainly highlights an overview of recent developments in multi-dimensional ZnO nanoarchitectures processed via low temperature, rational approaches and their functional properties in field emission devices and environmental remediation. In addition to these descriptions of controlled morphology design and the usage perspective, significant issues pertinent to such geometrical evolution and device performance determination and the possible outlook for low temperature research on ZnO are also described.

Optimal reliability, production lot size and safety stock in an imperfect production system

Abstract: This paper is concerned with the joint determination of optimal production lot size, safety stock and reliability parameter under the realistic assumptions that the production facility is subject to random breakdown of machinery system and also to change in the variable reliability parameter. Reliability of a machinery system is a decision variable that can be increased by more investment in production technology. In this model, preventive and corrective maintenance, safety stock for repair times and shortages are adopted to generalise the model. Except machinery breakdown, the manufacturing system may shift from in-control state to out-of-control state. During out-of-control state, a certain percentage of total production consists of defective items which can be reworked immediately at a cost to make as good as perfect quality items. The cost function is maximised by Khun-Tucker method. Numerical results are provided to illustrate both the study of the optimal solutions and sensitivity of different changes in key parameters.