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Yaw control systems orientate the rotor of a wind turbine into the wind direction, optimize the wind power generated by wind turbines and alleviate the mechanical stresses on a wind turbine. Regarding the advantages of yaw control systems, a k-nearest neighbor classifier (k-NN) has been developed in order to forecast the yaw position parameter at 10-min intervals in this study. Air temperature, atmosphere pressure, wind direction, wind speed, rotor speed and wind power parameters are used in 2, 3, 4, 5 and 6-dimensional input spaces. The forecasting model using Manhattan distance metric for k = 3 uncovered the most accurate performance for atmosphere pressure, wind direction, wind speed and rotor speed inputs. However, the forecasting model using Euclidean distance metric for k = 1 brought out the most inconsistent results for atmosphere pressure and wind speed inputs. As a result of multi-tupled analyses, many feasible inferences were achieved for yaw position control systems. In addition, the yaw position forecasting model developed was compared with the persistence model and it surpassed the persistence model significantly in terms of the improvement percent.  相似文献   
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Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) are frequently used to examine food web structure. Despite periphyton's importance to lake food webs, little is known about spatial variation of periphyton δ13C and δ15N values in the Great Lakes. We present periphyton δ13C and δ15N values from 28 sites the upper Great Lakes, including Lake Superior, the north shore of Lake Michigan, and Green Bay. We also examined variation in periphyton isotope values relative to several water quality parameters (TP, TN, TKN, NO3, Kd) as well as periphyton C:N. There was a large range in both periphyton δ13C (range = 13.5‰) and δ15N (range = 10.2‰) among sites. Periphyton in more eutrophic sites had more depleted δ13C and more enriched δ15N compared to more oligotrophic sites. Our finding of high variability in periphyton isotope values in the Upper Great Lakes has implications for stable isotope-based reconstructions of food web structure.  相似文献   
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The Technical Regulation of Good Practices for Brazilian Food Services (Regulamento Técnico de Boas Práticas para Serviços de Alimentação do Brasil) can be complemented by sanitary surveillance agencies at the state, district and municipal levels by tailoring it to location-specific requirements. The purpose of the present study was to survey sanitary legislation governing Brazilian Food Services. During the period from November 2011 to November 2012, a survey was conducted with the sanitary surveillance agencies from the various states, capitals and the Federal District. A previously prepared and tested tool was used for data collection, comprising 10 questions. Only 10 (19.2%) of the sanitary codes had been established prior to RDC Resolution n° 216/2004 and were not complementary. Of the legislation cited as complementary, only the states of Santa Catarina, Rio Grande do Sul and São Paulo and the capital of the state of São Paulo truly presented additional and location-specific aspects. No legislation that was specific to hospital kitchens was found. The majority of participating coordination, including the Evaluation List for Good Practices in Food Services, was also verified; however, it had not been published. In conclusion, a gap in sanitary surveillance services exists, which was caused by the lack of location-specific food service regulations.  相似文献   
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太湖流域主要湖泊的水域动态变化   总被引:3,自引:0,他引:3  
利用GIS和遥感技术对不同时期的地形图和遥感影像数据进行处理,获取3个时期(1971,1988,2002年)的太湖流域主要湖泊的水域面积。结合多种文献资料,对太湖流域主要湖泊的水域面积变化进行了研究,并分析了引起水域面积变化的主要因素。结果表明,1971~2002年期间太湖流域主要湖泊的水域面积减少了188.87 km2;湖泊水域面积减少的主要原因是由于人类活动的影响。在实地调查研究的基础上,对合理利用与保护湖泊水资源的对策进行了探讨。  相似文献   
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介绍了套管叉在锻压机上的模锻工艺,并结合生产实践具体分析了锻件在模锻过程中主要缺陷产生的原因和消除方法.  相似文献   
8.
Pool boiling heat transfer from nano-porous surface immersed in a saturated FC-72 dielectric fluid has been experimentally studied at atmospheric pressure (101 kPa). The data obtained from nano-porous surface (Anodisc 25) of thickness about 70 μm made from aluminum oxide (Al2O3) obtained from Whatman, were compared to that of a plain surface (aluminum) of thickness about 105 μm. From the experimental data obtained it was evident that there is a reduction of about 30% in the incipient superheat for the applied power for nano-porous surface over plain surface. SEM photographs of the nano-porous coating were taken for determining the size of the pores.  相似文献   
9.
描述用SOI技术制造的光耦合MOS继电器和多量子阱长波和红外探测器,以及集成异质结晶体管和激光二管于一体的高增益,高灵敏的光电子开关器件,文中着重介绍这些器件的结构,制造工和器件特性,并对其进行了讨论。  相似文献   
10.
BTM is a new And/Or parallel execution model for logic programs which exploits both full Or-parallelism and restricted And-parallelism.The advantages of high parallelism and low run time cost make BTJ,an experimental execution system of BTM implemented on a nonshared-memory multiprocessor system,achieve significant speedup for both And-paralled and Or-parallel logic programs.  相似文献   
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