排序方式: 共有4条查询结果,搜索用时 0 毫秒
1
1.
R. T. Haftka B. Grossman W. M. Eppard P. J. Kao D. M. Polen 《International journal for numerical methods in engineering》1989,28(3):593-607
The introduction of composite materials is having a profound effect on the design process. Because these materials permit the designer to tailor material properties to improve structural, aerodynamic and acoustic performance, they require a more integrated multidisciplinary design process. Because of the complexity of the design process numerical optimization methods are required. The present paper is focused on a major difficulty associated with the multidisciplinary design optimization process—its enormous computational cost. We consider two approaches for reducing this computational burden: (i)development of efficient methods for cross-sensitivity calculation using perturbation methods; and (ii) the use of approximate numerical optimization procedures. Our efforts are concentrated upon combined aerodynamic-structural optimization. Results are presented for the integrated design of a sailplane wing. The impact of our computational procedures on the computational costs of integrated designs is discussed. 相似文献
2.
Polen Michael R.; Curry Susan J.; Grothaus Louis C.; Bush Terry M.; Hollis Jack F.; Ludman Evette J.; McAfee Timothy A. 《Canadian Metallurgical Quarterly》2004,18(2):194
The authors examined children's depressed mood, parental depressed mood, and parental smoking in relation to children's smoking susceptibility and experimentation over 20 months in a cohort of 418 preteens (ages 10-12 at baseline) and their parents. Depressed mood in preteens was strongly related to experimentation but not to susceptibility. In cross-sectional analyses parental depressed mood was related to children's experimentation, but in longitudinal analyses parental depressed mood at baseline did not differentiate children who experimented from those who did not. Although parental smoking was strongly related to experimentation, it was not related to susceptibility either cross-sectionally or longitudinally. Depressed mood among preteens and parents appeared to be more strongly related to children's smoking behaviors than to their intentions to smoke. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
4.
Keith J. Smith Percy B. Polen D. M. de Vries Francis B. Coon 《Journal of the American Oil Chemists' Society》1968,45(12):866-869
Crude soybean and cottonseed oil were processed using simulated commercial processing procedures to determine if oil processing
would remove chlorinated pesticide contaminants of either natural or spiked origin. Two crude oil lots were spiked with endrin,
DDT, DDE, aldrin, dieldrin, heptachlor and heptachlor epoxide before processing. Representative samples of crude oil and products
following each processing step were analyzed for pesticide contamination. Results indicated that alkali-refining or subsequent
bleaching did not reduce chlorinated pesticide contamination. Hydrogenation prior to deodorization reduced endrin contamination.
Deodorization, with or without hydrogenation, eliminated chlorinated pesticides. The results of this study indicate that normal
commercial processing of crude vegetable oils for human consumption effectively removes any chlorinated pesticides which may
be present in crude oils. It is hypothesized that chlorinated pesticide removal is achieved by volatilization during deodroization,
which is supported by known volatilization characteristics, similarity of behavior in pesticides studied, and absence of the
pesticide or its conversion products in the finished oils, or both. 相似文献
1