Pawan Kumar

Bio: Pawan Kumar is an academic researcher from National Institute of Technology, Kurukshetra. The author has contributed to research in topics: Surface roughness & Machining. The author has an hindex of 7, co-authored 31 publications receiving 162 citations. Previous affiliations of Pawan Kumar include Indian Institute of Technology Indore.

Alizarin red S–zinc(II) fluorescent ensemble for selective detection of hydrogen sulphide and assay with an H2S donor

Abstract: A new Alizarin Red S based fluorescent probe ARS–Zn(II) has been reported for the detection of H2S in aqueous buffer solution. In the presence of zinc ions, ARS displayed an increase in fluorescence intensity through the formation of an ARS–Zn(II) ensemble. The addition of H2S to the ensemble caused the disassembly of the metal and ARS, which restored the fluorescence intensity of ARS. This sensing ensemble exhibited H2S-selectivity over other biothiols and biologically relevant analytes. The calculated detection limit of ARS–Zn(II) with H2S was 92 nM. ARS–Zn(II) also detected H2S in serum under physiological conditions. Moreover, as a practical application, it could be used for the real time monitoring of H2S released from the H2S-donor molecule benzoic (methyl carbonic) dithioperoxyanhydride and also applied to live cell imaging. The reported ensemble ARS–Zn(II) has advantages like ready availability, high selectivity with good sensitivity, fast response time, higher excitation (520 nm) and emission (625 nm) wavelengths and real time fluorescence assay with H2S donors.

Optimization of process parameters for WEDM of Inconel 825 using grey relational analysis

Abstract: Article history: Received October 28, 2017 Received in revised format: January 8, 2017 Accepted January 15, 2018 Available online January 15, 2018 Inconel 825 is high nickel-chromium-based superalloy which retains its mechanical properties and exhibits good corrosion and oxidation resistance at elevated temperature. Inconel 825 is extensively used for making aircraft engine parts like combustor casing and turbine blades in aero space industry. This research proposed the Response Surface Methodology with GRA to optimize multiple responses during Wire-cut EDM of Inconel 825. At optimum combination of input parameters i.e. A4B1C1D5E4F2, increase in MRR from 36.13 mm2/min to 41.822 mm2/min, decrease in SR from 2.842μm to 2.445μm and decrease in WWR from 0.01832 to 0.01758 was obtained. Experimental results showed that pulse-on time, wire feed, pulse-off time, and peak current significantly affected the MRR, and surface integrity of specimen and electrode with the formation of craters, pockmarks, debris, micro cracks, and recast layer. The optimal parametric combination obtained from the present study will be advantageous for working on high strength; high thermal conductivity and low melting point materials like nickel alloys. . 2018 by the authors; licensee Growing Science, Canada ©

Room temperature magneto-electric coupling in La–Zn doped Ba 1−x La x Fe 12−x Zn x O 19 ( x = 0.0–0.4) hexaferrite

Abstract: Barium hexaferrite powder samples with substitution of La+3 at Ba+2 and Zn+2 at Fe+3 site, according to the series formula Ba1−xLaxFe12−xZnxO19 (x = 0.0, 0.1, 0.2, 0.3, 0.4) have been prepared by the co-precipitation method. These samples were characterized by X-ray diffractometer (XRD), scanning electron microscopy, Polarization versus electric field loop tracer and vibrating sample magnetometer techniques. XRD patterns and Rietveld refinement indicate the single-phase formation of the magneto-plumbite barium hexaferrite for all the samples. Significant changes in dielectric properties are obtained by the different doping concentration of La and Zn. Ferroelectric loop for all the samples shows the lossy ferroelectric behaviour. Large spontaneous polarization is observed for x = 0.2 sample at room temperature. With increasing La and Zn doping content, the value of saturation magnetization and retentivity increases, and reaches a maximum value of 40.0 emu/gm and 24.0 emu/gm, respectively, for x = 0.2 sample and then decreases. To confirm the magneto-electric coupling, the second-order magneto-electric coupling coefficient β is measured through the dynamic method with the maximum value of ~ 1.69 × 10− 6 mV/cm.Oe2 for x = 0.2 sample at room temperature. The observations of room temperature magneto-electric coupling in these samples are useful for evolution of new multifunctional devices.

Analytical Study of Performance Parameters of InGaN/GaN Multiple Quantum Well Solar Cell

Abstract: An analytical study has been carried out to obtain the device performance parameters of InGaN/GaN-based multiple quantum well solar cell (MQWSC). Significant improvements are made upon the preexisting models reported in the literature for predicting device performance matrix for MQWSC. The American Society for Testing and Materials (ASTM) standards data sheets are utilized for attaining photon flux density instead of blackbody radiation formula. Furthermore, the photon flux density is utilized to evaluate the performance parameters of MQWSC and bulk p-i-n solar cell. Results suggest that by incorporating QWs in the intrinsic region ( ${x} = {0.1}$ in $\text{In}_{x}\text{Ga}_{{1}-{x}}\text{N}$ ), ∼27% increment in the conversion efficiency can be achieved as compared to that from the bulk solar cell. Moreover, the impact of operating temperature in the solar cell performance is also studied. The rise in temperature leads to an increase in short-circuit current density; however, open-circuit voltage and conversion efficiency decrease. A decrement of ∼9.7% in the conversion efficiency of MQWSC is observed with the rise in temperature from 200 to 400 K as compared to ∼11.6% decline in p-i-n solar cell.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON