Showing papers by "Gyanendra Singh published in 2012"

Robust parameter design and multi-objective optimisation of electro-discharge diamond face grinding of HSS

Abstract: In this paper a hybrid methodology comprising of Taguchi methodology and Response surface methodology has been applied for multi-objective optimization of Electro-Discharge Diamond Face Grinding (EDDFG) process. The approach first uses the Taguchi quality loss function to find the optimum level of input machining parameters such as wheel speed, current, pulse on-time and duty factor. The optimum input parameter values are further used as the central values in the response surface method to develop and optimize the second-order response model. The three quality characteristics material removal rate (MRR), wheel wear rate (WWR) and average surface roughness (ASR), which are of different nature, have been selected for optimization. The developed response surface model for each MRR, WWR and ASR has been found by TMRSM and the results of hybrid approach has been compared with the results of a Taguchi Methodology approach.

Generation of Optical Vortex Arrays Using Single-Element Reversed-Wavefront Folding Interferometer

Abstract: Optical vortex arrays have been generated using simple, novel, and stable reversed-wavefront folding interferometer. Two new interferometric configurations were used for generating a variety of optical vortex lattices. In the first interferometric configuration one cube beam splitter (CBS) was used in one arm of Mach-Zehnder interferometer for splitting and combining the collimated beam, and one mirror of another arm is replaced by second CBS. At the output of interferometer, three-beam interference gives rise to optical vortex arrays. In second interferometric configuration, a divergent wavefront was made incident on a single CBS which splits and combines wavefronts leading to the generation of vortex arrays due to four-beam interference. It was found that the orientation and structure of the optical vortices can be stably controlled by means of changing the rotation angle of CBS.

Modelling and optimisation of electro-discharge diamond face grinding of cemented carbide-cobalt composite

Abstract: Electro-discharge diamond grinding is a hybrid process of electrodischarge machining (EDM) and diamond grinding which is obtained by replacing the tool electrode of conventional EDM by a metal bonded diamond wheel. When face of the wheel is used for machining then the process is termed as electro-discharge diamond face grinding (EDDFG). In this study, modelling and optimisation of EDDFG of cemented carbide–cobalt composite has been done using a hybrid methodology comprising of Taguchi methodology (TM) and response surface methodology (RSM) with material removal rate (MRR), wheel wear rate (WWR) and average surface roughness (ASR) as the objective functions. The approach first uses the TM for finding the optimum level of input machining parameters such as wheel speed, current, pulse on-time and duty factor. The optimum input parameter values are further used as the central values in the RSM to develop second-order response model for MRR, WWR and ASR after conducting experiments using central composite rotatable design matrix. The simultaneous optimisation of weighted response has been obtained using MINITAB software. The results show considerable improvement in three quality characteristics when the hybrid approach is used, as compared with the results of only a TM approach.

Measurement of change in refractive index in polymeric flexible substrates using wide field interferometry and digital fringe analysis

Abstract: Indium tin oxide coated polyethylene terephthalate (PET) polymeric films are widely used as substrates for future optoelectronic devices, such as organic LEDs, organic thin film transistors, and organic solar cells. These PET substrates are thin, flexible, and rugged. But residual stresses are trapped in polymeric substrates due to their manufacturing process, and this leads to the birefringence in flexible displays. In this paper we report the measurement of the change in refractive index of PET substrates using Mach-Zehnder interferometry and the Fourier transform fringe analysis technique. Change in refractive index was observed by means of bending the PET substrate. This change in birefringence varies the optical path difference between the two arms of the interferometer, leading to the fringe shift. From the fringe shift the phase change was extracted as a function of bending, and the change in the refractive index was determined experimentally for two wavelengths, i.e., red and green color lasers. We found that the value of change in the refractive index of these substrates increases on bending of the substrates.

Selective recognition of Cd(II) using 5, 11, 17, 23-Tetra-tert-butyl-25,27bis(7’-methoxycoumarin-3’-methyloxy)-26, 28-dihydroxycalix[4]arene

Abstract: The work in this study is based on the selective determination of Cd(II) using 5, 11, 17, 23-Tetra-tert-butyl-25, 27bis(7’-methoxycoumarin-3’-methyloxy)-26, 28-dihydroxycalix[4]arene as neutral ionophore. The anion excluder KTpClPB and various plasticizers, viz., o-NPOE, DBP, DBBP, TEP, DOP, CN and OA have been used to improve the performance of sensor. The best performance was obtained with o-NPOE as plasticizer with composition PVC (33%): o-NOPE (54%): Ionophore (5%): NaTPB (8%). This sensor exhibits Nernstian response with slope 23.0 ± 0.3 mV/decade of activity in the concentration range 1.0×10−9to 1.0×10−1M of Cd(II), performs satisfactorily over wide pH range of (2.0–8.6) with a fast response time (10s). The proposed sensor can be used over a period of 10 months without significance drift in potential. It has been used successfully for direct determination of Cd(II) in different real samples.

Genetic analysis and traits association in two double haploid populations of bread wheat (Triticum aestivum L.)

Abstract: A study was conducted for genetic analysis and estimating association of the traits in double haploid populations of bread wheat (Triticum aestivum L.). These populations were planted at Directorate of Wheat Research, Karnal during rabi season 2008-09 and 2009-10 in augmented design along with five checks in three blocks, wherein all checks were repeated in each block. The genetic variance and correlation coefficients were carried out for assessment of the performance of double haploid lines derived from the cross (Ducula4/2* Brookton) and (Camm/ HD 2329), through six metric traits, viz. plant height, days to heading, days to maturity, tillers per plot, 1000-grain weight and grain yield. Analysis of variance on the basis of F- values, revealed wide variability for most of the traits over the year and pooled. The phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all traits, while high heritability (<60%) coupled with high genetic advance (<15%) was found for all the traits, excepting the days to maturity and spike length. At phenotypic level, positive and significant correlation coefficients revealed that grain yield is directly influenced by spike length, tillers per plot and thousand grain weight, while significant and negative correlations was found of plant height and days to maturity with grain yield, respectively in both the populations. There is wide genetic diversity available for metric traits, which may be utilized for yield improvement in bread wheat through planned hybridization and selection. The traits plant height, maturity days, tillers per plot, spike length and 1000-grain weight of both populations can be of importance in further yield enhancement.

Novel Polymeric Membrane Sensor for the Selective Determination of Citrazine

Abstract: The highly selective and sensitive PVC based membrane sensor was fabricated by using 1,3,5-tris[(2,3dihydroxybenzylamino) aminomethyl]cyclohexane (L) as a neurtal membrane carrier for the potentiometric determination of citrazine. The membrane with the composition of 30% PVC, 66% o-NPOE, 3% ionophore and 1% NaTPB was found to be best in terms of response characteristics of sensor assembly. The proposed membrane sensor has very low detection limit of 2.0 x 10−8M, within the concentration range of 5.0 x 10−8– 1.0 x 10−2M, and has fast response time of about 10s. The proposed sensor was used for the selective determination of citrazine in different synthetic as well as real sample.

Corrosion inhibition of mild steel in sulphuric acid solutions by using tetra methyl ammonium bromide (TMAB)

Abstract: The corrosion inhibition of mild steel in one normal sulphuric acid solution by tetra methyl ammonium bromide (TMAB) has been studied in relation to the concentration of the inhibitor as well as the temperature using electrochemical polarization (galvanostatic and potentiostatic polarizations) techniques. The results were supplemented with scanning electron microcopy and infra-red spectroscopy. All the methods employed are in reasonable agreement. There is no particular relationship of inhibition with concentration and temperatures. The thermodynamic functions of dissolution and adsorption processes were calculated from experimental polarization data and the interpretation of the results are given. Adsorption of TMAB was found to follow the Langmuir’s adsorption isotherm. TMAB is a mixed type of inhibitor. Key words: Tetra methyl ammonium bromide (TMAB), corrosion inhibitors, mild steel, sulphuric acid (H2SO4), thermodynamic functions, adsorption process, scanning electron microscope (SEM), infrared spectroscopy (IR) spectra.