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Optimization of passive control performance for different hard disk drives subjected to shock excitation

Journal of Central South University 2017年第4期24卷 891-899页

作者： Seyed Rashid Alavi Mehdi Rahmati Saeed Ziaei-Rad Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156-83111 Iran isfahan mathematics house Isfahan 81698-51177 Iran

Laptop personal computers(LPCs) and their components are vulnerable devices in harsh mechanical environments. One of the most sensitive components of LPCs is hard disk drive(HDD) which needs to be protected against damages attributable to shock and vibration in order to have better magnetic read/write performance. In the present work, a LPC and its HDD are modeled as two degrees of freedom system and the nonlinear optimization method is employed to perform a passive control through minimizing peak of HDD absolute acceleration caused by a base shock excitation. The presented shock excitation is considered as half-sine pulse of acceleration. In addition, eleven inequality constraints are defined based on geometrical limitations and allowable intervals of lumped modal parameters. The target of the optimization is to reach optimum modal parameters of rubber mounts and rubber feet as design variables and subsequently propose new characteristics of rubber mounts and rubber feet to be manufactured for the HDD protection against shock excitation. The genetic algorithm and the modified constrained steepest descent algorithm are employed in order to solve the nonlinear optimization problem for three widely-used commercial cases of HDD. Finally, the results of both optimization methods are compared to make sure about their accuracy.

关键词： hard disk drive passive control shock excitation sequential quadratic programming genetic algorithm rubber

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Assessment of Variabilities in Wheat Genotypes to Yellow and or Strip Rust, Puccinia striiformis in Glass house Conditions

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Journal of Agricultural Science and Technology(A) 2011年第2X期1卷 255-261页

作者： M. Nasr Esfahani M. Monazah G. Alizade Sh. Rafizadeh Agricultural and Natural Resources Research Center Isfahan 81785199 Iran

Yellow/stripe rust caused by Puccinia striiformis is a major problem in the Middle East specially Iran. Virulence survey of cereal rust fungi have traditionally used differential host genotype and virulent physiologic race 134 E 134 AT was received to evaluate the segregating lines. A set of 35 segregating lines and three additional susceptible cultivars were added, making a total of 38 eultivars-lines. Spreader plants served as a source of inoculums. The plants were evaluated after two months based on infection percentage and the disease scoring scales. The results indicated that, there are significant changes in susceptibility assessments of the segregating lines in contrast to cultivated varieties to the yellow rust P. striiformis as far as the disease incidence and rust development is concerned in these experiments. The selected differential genotypes associated with various levels of resistance. The infection percentages were varied on the lines and the varieties, whereas the severity percentages were entirely different. The lowest severity is of line 38 with 34.70% and the highest in line 1 with 93.49% indicating 2.7 folds reduction in severity. For discrimination among the lines, the results on scoring scales gave distinctions of five classes of resistance, in which, the highest score is 29.93 and the lowest one 11.46. The cluster analysis showed almost similar results and confirmed, the analysis by Duncan＇s Multiple-lest rang as the above five distinctive groups.

关键词： Genotype isfahan race resistance severity varieties.

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