http://nopr.niscair.res.in/handle/123456789/8398 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/8474 Title: Phase transition in Pb[(Mg_3/4Cu_1/4)_1/3Nb_2/3]O₃ ceramic <br/> <br/>Authors: Kumar, Amit; Prasad, K; Choudhary, S N; Sinha, T P <br/> <br/>Abstract: Single phase perovskite-type cubic ceramics of Pb[(Mg_3/4Cu_1/4)_1/3Nb_2/3]O₃ (PMCN) were synthesized by high temperature double step solid state reaction technique. Dielectric studies show relaxor behaviour with diffuse phase transition. The phase transition (<i style="">T_m</i>) occurs at -22°C at 10 kHz. The frequency dependence of <i style="">T_m</i> has been modeled using Vogel-Fulcher relation. The dielectric relaxation in PMCN is found analogous to the magnetic relaxation in spin-glass system. The relaxor behaviour in PMCN has also been examined through admittance spectroscopy. <br/> <br/>Page(s): 586-590 http://nopr.niscair.res.in/handle/123456789/8473 Title: Flexural vibrations of non-homogeneous elliptic plates <br/> <br/>Authors: Chakraverty, S; Jindal, Ragini; Agarwal, V K <br/> <br/>Abstract: The effect of non-homogeneity of material for complex shaped plates on their vibration frequencies is analyzed. Corresponding mathematical model has been developed. The results have been included for the first few frequencies of the plate element that are important to know before finalizing the design of a structure. Rayleigh Ritz method with generation of orthogonal polynomials using Gram-Schmidt process is used. In the numerical results, present solution is carefully examined by a convergence test and comparison with known results for special cases are carried out. <br/> <br/>Page(s): 521-528 http://nopr.niscair.res.in/handle/123456789/8472 Title: Influence of shot peening intensity on fatigue design reliability of 65Si7 spring steel <br/> <br/>Authors: Aggarwal, M L; Khan, R A; Agrawal, V P <br/> <br/>Abstract: A lot of research has been done to improve the fatigue strength of metallic materials by creating compressive residual stress field (CRSF) in their surface regions through shot peening. In this paper, the axial fatigue strength of 65Si7 spring steel is evaluated experimentally as a function of shot peening intensity for the application in the automotive vehicles. Fatigue life at various shot peening conditions is determined with S/N curves and optimum shot peening intensity is also determined. The effect of Almen intensity on compressive residual stress and relaxation of compressive residual stress have been discussed for fatigue life extension. Shot peening of leaf springs is illustrated to cause improvement in fatigue strength, reduction in weight and reliability. A flow chart has been developed for improvement in fatigue design of components for economy. <br/> <br/>Page(s): 515-520 http://nopr.niscair.res.in/handle/123456789/8471 Title: Optimizing diesel engine parameters for emission reduction using Taguchi method: Variation risk analysis approach – Part II <br/> <br/>Authors: Nataraj, M; Arunachalam, V P; Dhandapani, N <br/> <br/>Abstract: Taguchi parameter design research methodology allows one to make products or processes robust to uncontrollable noise factors and will also reduce the number of experiments to be carried out to arrive an optimized system. The main objective of this work is to study the various operating parameters of diesel engine to propose modified engine parameter (optimum) settings for reduction in NO_X, HC, CO and smoke concentrations simultaneously in diesel emission by applying Taguchi parameter design concept. Taguchi L₁₈ (2¹<img src='/image/spc_char/cross.gif' border=0>3⁷) quality design concept mixed orthogonal array has been used to determine the S/N ratio (dB), analysis of variance (ANOVA) and <i style="">F</i>₀ test values for recognizing most significant engine operating parameters that influence exhaust emission. The experimental results give an idea about how the variations in engine settings like nozzle spray holes, piston-to-head clearance, nozzle protrusion, injection control pressure, start of injection timing and swirl level alter the pollutant (NO_X, HC, CO and smoke) intensity in emission. Considering these significant engine-operating parameters, verification of the improvement in the quality characteristics for emission reduction has been done through confirmation test with reference to the chosen initial or reference parameter settings. These confirmation test results prove that the optimal combination of diesel engine parameters obtained from the investigation reducing the pollutant levels in exhaust emission in reality<i style="">.</i> <br/> <br/>Page(s): 505-514