检索结果-南通市图书馆

Techno-economic evaluation of wind energy in southwest Nigeria

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2012年第4期6卷 366-378页

作者： Muyiwa S. ADARAMOLA Olarenwaju M. OYEWOLA Olayinka S. OHUNakiN rufus R. DINRIFO Department of Energy and Process Engineering Norwegian Universityof Science and Technology Trondheirn 7030 Norway Department of Mechanical Engineering University of Ibadan Oyo State23402 Nigeria Mechanical Engineering Department Covenant University Ogun State11001 Nigeria School of Engineering Lagos State Polytechnic Lagos 23401 Nigeria

In this study, an analysis of the wind energy potential in the southwest geo-political region of Nigeria was conducted. A 37-year （1971-2007） wind speed data set measured at 10m height, obtained from eight meteorological stations within the region was analyzed using a 2-parameter Weibull function. Besides, a techno- economic evaluation of large wind energy conversion systems with power ratings ranging from 0.6 to 2 MW at different hub heights based on the levelized unit cost of electricity was made for the different sites considered. The result showed that electricity cost varied from 0.06997 and 0.11195 S/（kW. h） to 2.86611 and 4.585785/（kW-h） at limit values of turbine specific cost band intervals of 1000 and 1600 S/kW. It was further shown that Lagos, having the highest accumulated power outputs of 430.10kW/a from DeWind D7 at 70 m hub height, is the most preferred for economically usable power generation in terms of the levelized unit cost.

关键词： mean wind speed Weibull distributions windturbine techno-economic analysis southwest geopoliticalregion Nigeria

美国南加州Ridgecrest M W6.4-M W7.1地震地表破裂几何学及运动学特征

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

地球物理学报 2021年第4期64卷 1206-1214页

作者：马振宁钱荣毅 rufus Catchings Mark Goldman 祁生文中国地质大学(北京)地球物理与信息技术学院北京100083 美国地质调查局地震科学中心(USGS-ESC) 莫菲特菲尔德940353 中国科学院地质与地球物理研究所北京100029

2019年7月4—6日位于美国南加州城市Ridgecrest附近地区,在不足两天的时间内接连发生了一系列地震,其中包括震级达M W6.4和M W7.1的强震.震后两天对震中区产生的地表破裂进行了实地地质调查和测量,发现两次地震分别产生了NW方向长度50 k... 详细信息

2019年7月4—6日位于美国南加州城市Ridgecrest附近地区,在不足两天的时间内接连发生了一系列地震,其中包括震级达M W6.4和M W7.1的强震.震后两天对震中区产生的地表破裂进行了实地地质调查和测量,发现两次地震分别产生了NW方向长度50 km和NE方向长度10 km的两条破裂带.根据野外调查,NW方向的地表破裂表现出右旋走滑特征,是M W7.1地震产生的破裂带,而NE方向的地表破裂表现为左旋走滑性质,是M W6.4地震产生的破裂带.地表破裂野外调查和地震序列统计分析表明,NW方向是本次地震序列的主要破裂带,释放了本次地震的大部分地震矩.通过发震的时序关系和地震序列密集条带分布推断,本次地震是NE和NW两个方向应力作用下,两条共轭断层先后破裂产生的一组复杂共轭地震,推测M W6.4地震是一次强烈前震,促进了震级更大的M W7.1主震发生.

关键词： Ridgecrest地震地表破裂野外调查几何学

THD Reduction for Permanent Magnet Synchronous Motor Using Simulated Annealing

在线全文

学校读者我要写书评

暂无评论

Intelligent Automation & Soft Computing 2023年第2期35卷 2325-2336页

作者： R.Senthil Rama C.R.Edwin Selva Rex N.Herald Anantha rufus J.Annrose Department of Electrical&Electronics Engineering Kalaivanar N S K College of EngineeringNagercoil629001India Department of Electrical&Electronics Engineering Vignana Bharathi Institute of TechnologyHyderabad501301India Department of Electronics and Communication Engineering Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and TechnologyChennai600062India Department of Information Technology St.Xavier’s Catholic College of EngineeringNagercoil629003India

Any nonlinear behavior of the system is analyzed by a useful way of Total Harmonic Distortion(THD)*** THD achieves lower peak current,higher efﬁciency and longer equipment life *** annealing(SA)is applied due to the effectiveness of locating solutions that are close to ideal and to challenge large-scale combinatorial optimization for Permanent Magnet Synchronous Machine(PMSM).The parameters of direct torque controllers(DTC)for the drive are automatically adjusted by the optimization *** of the PI-Fuzzy-SA algorithm are retained when used *** also improves the rate of system *** response improvement and har-monic reduction is achieved with SA-based DTC for *** mechanism is known to be faster than other ***,it is observed that as compared to other algorithms,the projected algorithm yields a reduced total harmonic *** a result of the employment of Space Vector Modulation(SVM)techni-que,the system is resistant to changes in motor speciﬁcations and load *** MATLAB&Simulink simulation,the experiment is done and the per-formance is calculated for the controller.

关键词： PMSM simulated annealing space vector modulation direct torque control THD

群胚的粗上同调和Connes-Chern特征映射

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国科学：数学 2017年第12期47卷 1879-1890页

作者：唐翔 WILLETT rufus 姚一隽 Department of Mathematics Washington University Department of Mathematics University of Hawai’i 复旦大学数学科学学院上海200433

本文引入群胚上粗上同调群的概念,构造了一个从群胚粗上同调群映到群胚Roe*-代数循环上同调群的Connes-Chern特征映射.作为例子,本文构造了平坦G-主丛所定义的和乐(holonomy)群胚上的一个粗上同调类.

关键词：群胚粗几何循环上同调

Strong Relationship between Dry-Season Rainfall over West Africa and Extratropical Disturbance

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science and Engineering 2017年第4期7卷 217-229页

作者： Ewanlen Inegbenoise rufus Adeyeye Joseph Department of Water Resources & Agro-Meteorology Federal University Oye-Ekiti P.M.B. 3 73 Ekiti 0100 Nigeria

The recent concerns for food security over Africa related to several climatic factors, such as the strength of the flood and drought within the growing and harvesting seasons and the long-term rainfall variability have motivated the study of identifying the extratropical causes of ＂anomalous＂ dry-season precipitation for the region. The paper examines the role of upper level disturbance in the unusual rainfall over the tropical region of West Africa in the dry-season for the month of December, 2014. The rainfall is examined using the GPCP （global precipitation climatology project） merged satellite-gauge daily precipitation estimate and station rain-gange measurements obtained from Nigeria Meteorological Agency. While the atmospheric circulation features are determined by using the NCEP-NCAR （National Centers for Environmental Prediction-National Center for Atmospheric Research） reanalysis dataset, composites of NCEP/NCAR Reanalysis wind fields, pressure, temperature, humidity and moisture fluxes suggest that rainfall event that affected few countries （Nigeria, Ghana ＆ Cote d＇Ivoire） during the period is linked with an enhanced on-shore westerly low-level flow from the Gulf of Guinea into inland, northward displacement of ITD （Inter-Tropical Discontinuity）, intensification of the weak dry-season Sahara heat-low and upper-cyclonic vortex which help the generating of convection over the region. The influence of synoptic systems was also evident in the rainfall analysis for December, 2014. During the periods of study, the observed low-level flow over West Africa is likely to be an important contributor to the observed dry-season heavy rainfall, regulated by extra-tropical synoptic scale disturbances. The results provide an important basis for further studies on several cases over the past decade years producing heavy rainfall exceeding some kind of climatological, statistically-based threshold.

关键词： ITD upper-level disturbance precipitation tropical region.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Animal Models and Experimental Medicine 2018年第4期1卷 295-304页

作者： Olaoluwa Sesan Olukiran rufus Ojo Akomolafe Olutosin Samuel Ilesanmi Christian Eseigbe Imafidon Quadri Kunle Alabi Department of Physiological Sciences Faculty of Basic Medical Sciences Obafemi Awolowo University Department of Biochemistry and Molecular Biology Faculty of Sciences Obafemi Awolowo University Department of Physiology Faculty of Basic Medical and Health Sciences Bowen University

Background: The study determined the fractions of proteins in the urine and plasma of rats at different ages, measured the plasma and urine concentrations of markers of renal function, with a view to determining the influence of proteinuria on renal ***: Eighty Wistar rats were used for this study. Groups 1 and 2 each consisted of eight 1-month-old male and female rats; 3 and 4 had eight 3-month-old male and female rats; 5 and 6 had eight 6-month-old male and female rats; 7 and 8 had eight 9-month old male and female rats; and 9 and 10 had eight 12-month-old male and female ***: A fraction of the molecular weight of protein in the urine of rats aged 1, 9 and 12 months was higher than that of 3 and 6 months. The total protein concentration in the urine of male and female rats aged 9 and 12 months was significantly higher than that of rats aged 1 and 3 months. The urine creatinine concentrations of male and female rats aged 9 months were significantly higher when compared with that of 1, 3, 6 and 12 ***: Our results suggest that the 3-month-old rats seem less affected by proteinuria, because they had the least urine protein, and consistent and reduced plasma and urine concentrations of markers of renal function. The results of this study may provide a foundation for future mechanistic inquiries as to why this age group was the least affected by proteinuria.

关键词： creatinine electrophoresis protein rats urea

Surface Temperature Anomalies in the River Niger Basin Development Authority Areas, Nigeria

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Climate Sciences 2013年第4期3卷 532-537页

作者： Joseph Sunday Babatolu rufus temi.ayo aki.nubi Department of Geography Adeyemi College of Education Ondo Nigeria Department of Physics Adeyemi College of Education Ondo Nigeria

The study investigates the trends in temperature in the Upper and Lower Niger Basin Development Authority Areas using standardized Anomaly Index, Gaussian Low Pass and Spearman’s correlation coefficient. From the data collected and analyzed, the mean annual temperature and mean annual maximum temperature demonstrated pronounced temporal increasing trend in the period 1951-2010 while the mean annual minimum temperature showed no trend. The rate of increase in mean annual temperature, mean annual maximum and minimum temperatures was 0.45°C, 0.40°C and 0.20°C respectively. The mean annual maximum temperature warmed faster than the mean annual minimum leading to increase in diurnal range of temperature. The annual temperature anomaly in the study area tracks the observed anomalies for the Northern Hemisphere in the 20th century. The decadal temperature increase is very small particularly as from 1980.

关键词： Temperature Anomalies River Niger Basin Development Authority Area

Discussion on Establishing a Metrology Standard for Vibration-Driven Energy Harvesting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy and Power Engineering 2012年第5期6卷 674-682页

作者： Adekunle rufus Akande Action Nechibvute Pearson Luhanga Physics Department University of Botswana Gaborone Gaborone Private Bag 00704 Botswana Physics Department Midlands State University Gweru Gweru Private Bag 9055 Zimbabwe

Energy harvesting is an area of substantial and increasing research attention, and vibration-based devices dominate this research. The primary goal of most researchers is producing maximum electrical output from the harvester systems. However, there have been little metrological considerations for circumstances under which the energy harvester devices are characterized. This makes comparison of different device prototypes very difficult. It is the focus of this paper to highlight the need for metrological considerations to energy harvesting so that a universal metric can be developed. An attempt is also made to discuss the critical parameters that are essential in establishing an international standard on vibration-based energy harvesting. Finally, a simple standard for energy harvesting is proposed.

关键词： Metrology standard energy harvesting metric vibration energy.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

《星球大战》:建立了一个行业的电影

疯狂英语（初中天地） 2005年第8期 7-9页

作者： rufus Wakely 洪洪

George Lucas comments on the making of Star Wars: 乔治·卢卡斯谈制作《星球大战》的经历: “When you’re directing[导演],you have to get up at four thirty,have breakfast at five,leave the hotel at six,drive an hour to location[外景拍摄场地],start shooting[拍摄] at eight,and finish shooting around *** you wrap[结束摄制],go to your office,and set up the next day’s *** get back to the hotel about eight or nine-

关键词：《星球大战》星球大战卢卡斯