Contents of Journal of Mechanical Engineering 62, 5-6 (2011)

                                                                       
JAM, J. E., FARJAMPOUR, E., TAJDARI, M., NIA, N. G.: A new method for
identification of mechanical properties in free laminated composite 
plates using genetic algorithm                                         251                                                      

PANDEY, A., SINGH, S.: Some investigations into the electrical 
discharge machining of super alloy using a rotating disc electrode     263

ATTIA, H. A., ABDEEN, M. A. M.: Unsteady generalized Couette flow 
with heat transfer considering the Hall effect                         279                     

NITHYANANDAN, N., SENDILVELAN, S., BALAJI, N.: Electrically heated
transition metal oxide catalyst for reducing HC/CO emissions 
from automobile                                                        289

BERI, N., MAHESHWARI, S., SHARMA, C., KUMAR, A.: Machining performance
evaluation during electric discharge machining of Inconel 718 using 
the Taguchi methodology                                                299

UTPAT, A., INGLE, R. B., NANDGAONKAR, M. R.: Study of vibration 
response characteristics of deep groove ball bearings with localized 
defect on its races                                                    311

This work presents a simple technique to identify elastic properties of composite materials. The identification is based on the adjustment of coefficients in an optimization process in which the objective function is defined by the difference between the analytical natural frequencies and the experimental measured ones. Such analytical natural frequencies are obtained by the Rayleigh-Ritz technique while the experimental ones are determined by ordinary modal tests. The proposed approach used Genetic Algorithm (GA) to solve the optimization problem. This paper describes an indirect (non-destructive) prediction method by using GA and the analytical Rayleigh-Ritz technique. A few examples are presented to identify the material properties of orthotropic rectangular plates with unidirectional fiber plies and completely free boundary conditions (FF-FF) for this research.

The unsteady Couette flow of an electrically conducting, viscous, incompressible fluid bounded by two parallel insulating porous plates is studied with heat transfer considering the Hall effect. An external uniform magnetic field and a uniform suction and injection are applied normal to the plates while a uniform and constant pressure gradient is imposed in the axial direction. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are included in the energy equation. The effects of the Hall current and the uniform suction and injection on both the velocity and temperature distributions are investigated and interesting results are reported.

Cold-start emissions represent the greatest concentration of emissions from today's catalyst equipped vehicle. The existing catalytic converters are successful in reducing emissions after engine warm-up. The catalyst is not active during this warm-up period due to its low operating temperature. Emission reduction is possible by heating and changing the composition of catalyst used in automobile. This paper deals with the potential of catalytic systems with electrically heated metal oxide catalyst and the presentation of thermal analysis provides insight into the catalytic system. In this investigation, an attempt is being made to study the pollution from multi-cylinder SI engine, by developing improved catalysts. It is found that the electrically heated catalytic converter (EHC) with copper oxide catalyst when used with existing catalytic converter, the HC and CO emissions are reduced considerably.

In this paper, an attempt has been made to evaluate the machining performance during electrical discharge machining (EDM) of Inconel 718 with different electrode compositions and EDM oil as dielectric medium. An L36 (2¹ x 3⁷) orthogonal array based on the Taguchi method has been adopted to conduct series of experiments. The machining parameters selected for the study are polarity, electrode type, peek current, pulse on time, duty cycle, gap voltage, retract distance, and flushing pressure. Machining performance is evaluated in the form of material removal rate and wear ratio and experimental results are statistically evaluated using analysis of variance (ANOVA).
Experimental results show that it is possible to process nickel based superalloy, Inconel 718, via electric discharge machine with powder metallurgy processed electrodes. The significant parameters that critically influenced the machining characteristics were examined, and the optimal combination levels of machining parameters for material removal rate and wear ratio were also determined. The results were verified through confirmation experiments.

The present work is focused on development of mathematical model with two degrees of freedom for deep groove ball bearing with simply supported arrangement of loading on test bearing. The current work puts also emphasis on determination of defect frequencies for outer and inner ring defected bearings. Single row deep groove ball bearings with contact angle zero are considered in the present work. The model has been developed as spring-mass system by assuming races as masses and balls as nonlinear contact springs. The actual measurements of vibration amplitudes of bearings with artificial local defects have been carried out for verification of theoretical results. It is noted that the theoretical results show good agreement with the experimental results. Theoretically, amplitudes of vibration become zero when the defect is outside the load zone but practically some non zero amplitude levels have been observed for the defect position even outside the load zone.