检索结果-南通市图书馆

Exergy-energy analysis of full repowering of a steam power plant

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2015年第1期9卷 54-67页

作者： s. NIKBAKHT nasERABAD A. mEHRPAnaHI m. R. ALIGOODARZ K. mOBINI Department of mechanical Engineering Shahid Rajaee Teacher TrainingUniversity Tehran *** Iran

A 320 mW old steam power plant has been chosen for repowering in this paper. Considering the technical conditions and working life of the power plant, the full repowering method has been selected from different repowering methods. The power plant repower- ing has been analyzed for three different feed water flow rates： a flow rate equal to the flow rate at the condenser exit in the original plant when it works at nom.nal load, a flow rate at maximum load, and a flow rate when all the extractions are blocked. For each flow rates, two types of gas turbines have been examined： V94.2 and V94.3A. The effect of a duct burner has then been investigated in each of the above six cases. steam is produced by a double- pressure heat recovery steam generator （HRsG） with reheat which obtains its required heat from the exhaust gases coming from the gas turbines. The results obtained from modeling and analyzing the energy-exergy of the original steam power plant and the repowered power plant indicate that the maximum efficiency of the repowered power plant is 52.04%. This maximum efficiency occurs when utilizing two V94.3A gas turbines without duct burner in the steam flow rate of the nom.nal load.

关键词： full repowering exergy analysis V94.2 andV94.3A gas turbines double-pressure HRsG duct burner,Bandarabbas steam power plant efficiency

Investigating structural impact of a valine to isoleucine substitution on anti-müllerian hormone in silico and genetic association of the variant and AmH expression with egg production in chickens

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2020年第6期19卷 1635-1643页

作者： DANG Li-ping LIU Rui-fang ZHAO Wen-yan ZHOU Wen-xin mIN Yu-na WANG Zhe-peng College of Animal science and Technology Northwest A&F UniversityYangling 712100P.R.China Key Laboratory of Animal Genetics Breeding and Reproduction of Shaanxi ProvinceYangling 712100P.R.China

Anti-mullerian hormone(AmH)acts in maintaining orderly cyclic recruitment of early follicles,suggesting that it is a promising can didate for in flue ncing an imal reproductive *** study aimed to elucidate the effect of a missense mutati on of Val566lle on the structure of AmH protein and the genetic association of Val566lle and AmH expression with egg production in *** perturbations of Val566lle were predicted by homology *** association of the variant with the number of eggs was tested using a quantitative trait transmission disequilibrium test *** expression in granulosa cells in Lueyang black-boned chickens was compared with that in Nick *** Vai566 of AmH is a non?conservative amino acid among mammals and birds,but its hydrophobicity is completely *** substitution of Vai566 for lie566 pote ntially disrupted hydroge n bonds and solve nt accessibility of 22 residues and created a short a-helix in the C terminus of *** having striking structure-disrupting potential,the variant was not statistically associated with the number of eggs(P>0.05)in the Lueyang black-boned *** did not detect differential expression of AmH betwee n Lueya ng black-b oned chicke ns and Nick chickens(P>0.05).These results con firmed the structural impact of Val566lle,but suggested that Val566lle and AmH expression might not be the major genetic determ.nants for egg production in Lueyang black-boned chickens.

关键词： chicken egg production anti-mullerian hormone follicle recruitment

Flow of Casson nanofluid with viscous dissipation and convective conditions: A mathematical model

在线全文

学校读者我要写书评

暂无评论

Journal of Central south University 2015年第3期22卷 1132-1140页

作者： T.HUssAIN s.A.sHEHZAD A.ALsAEDI T.HAYAT m.RAmZAN Department of mathematics Faculty of Computing Mohammad Ali Jinnah University Department of mathematics Comsats Institute of Information Technology Department of mathematics Faculty of Science King Abdulaziz University Department of mathematics Quaid-i-Azam University

The magnetohydrodynamic(mHD) boundary layer flow of Casson fluid in the presence of nanoparticles is *** conditions of temperature and nanoparticle concentration are employed in the formulation. The flow is generated due to exponentially stretching surface. The governing boundary layer equations are reduced into the ordinary differential equations. series solutions are presented to analyze the velocity, temperature and nanoparticle concentration fields. Temperature and nanoparticle concentration fields decrease when the values of Casson parameter enhance. It is found that the Biot numbers arising due to thermal and concentration convective conditions yield an enhancement in the temperature and concentration fields. Further, we observed that both the thermal and nanoparticle concentration boundary layer thicknesses are higher for the larger values of thermophoresis parameter. The effects of Brownian motion parameter on the temperature and nanoparticle concentration are reverse.

关键词： nanoparticles Casson fluid concentration convective condition

Effect of rock joint roughness on its cyclic shear behavior

在线全文

学校读者我要写书评

暂无评论

Journal of Rock mechanics and Geotechnical Engineering 2017年第6期9卷 1071-1084页

作者： s.m.mahdi Niktabar K.seshagiri Rao Amit Kumar shrivastava Department of Civil Engineering Indian Institute of Technology Delhi Department of Civil Engineering Delhi Technology University

Rock joints are often subjected to dynamic loads induced by earthquake and blasting during mining and rock cutting. Hence, cyclic shear load can be induced along the joints and it is important to evaluate the shear behavior of rock joint under this condition. In the present study, synthetic rock joints were prepared with plaster of Paris(Po P). Regular joints were simulated by keeping regular asperity with asperity angles of 15°-15° and 30°-30°, and irregular rock joints which are closer to natural joints were replicated by keeping the asperity angles of 15°-30° and 15°-45°. The sample size and amplitude of roughness were kept the same for both regular and irregular joints which were 298 mm×298 mm×125 mm and 5 mm, respectively. shear test was performed on these joints using a large-scale direct shear testing machine by keeping the frequency and amplitude of shear load under constant cyclic condition with different normal stress values. As expected, the shear strength of rock joints increased with the increases in the asperity angle and normal load during the first cycle of shearing or static load. With the increase of the number of shear cycles, the shear strength decreased for all the asperity angles but the rate of reduction was more in case of high asperity angles. Test results indicated that shear strength of irregular joints was higher than that of regular joints at different cycles of shearing at low normal stress. shearing and degradation of joint asperities on regular joints were the same between loading and unloading, but different for irregular joints. shear strength and joint degradation were more significant on the slope of asperity with higher angles on the irregular joint until two angles of asperities became equal during the cycle of shearing and it started behaving like regular joints for subsequent cycles.

关键词： Cyclic shear test shear behavior shear strength Regular joint Irregular joint Joint dilation Asperity degradation

Optical transmission in thin films of vanadium compounds

在线全文

学校读者我要写书评

暂无评论

Journal of semiconductors 2014年第7期35卷 10-14页

作者： Kh.s.Karimov m.mahroof-Tahir m.saleem N.Ahmad A.Rashid GIK Institute of Engineering sciences and Technology TopiDistrict SwabiKPK 23640Pakistan Physical Technical Institute of Academy of sciences Rudaki Ave33Dushanbe 734025Tajikistan saint Cloud state University 720 Fourth Avenue SouthSaint CloudMN 56301-4498USA Government College of science Wahdat RoadLahore 54570Pakistan

Thin films of five vanadium compounds/composite：（1） VO2（3-fl）（3-fl = 3-Hydroxyflavone）, （2） VO（pbd）：（pbd = 1-Phenyl-l, 3-butadione）, （3） VO（dbm）2 （dbm = Dibenzoylmethane）, （4） VPc （Vanadyl Phthalocyanine） and （5） V2O5-PEPC （V2O5- poly-N-epoxypropylcarbazole composite）, were deposited by the dropcasting method from the solution in benzene. The transmittance-irradiance relationships were investigated and the transmission in the visible spectrum and optical images were obtained as well. It was found that the transmittance of the VO2（3-fl）, VO（pbd）2, VO（dbm）2 and VPc, was practically independent of the irradiance; whereas the transmittance of V2O5-PEPC decreased by 4% for thin and 9% for thick films with an increase of the irradiance.

关键词： vanadium compound/composite semiconductor thin film transmittance irradiance

在线全文

学校读者我要写书评

暂无评论

深圳市创新空间结构测度与影响因素分析

广州大学学报（自然科学版） 2024年第3期23卷 82-92页

作者：王玉娇千庆兰陈清怡杨娜广州大学地理科学与遥感学院广东广州510006 华南理工大学建筑学院广东广州510641

作为创新活动的重要载体,创新空间是近年来创新地理学领域关注的重点内容。文章将深圳市创新空间划分技术型、知识型和孵化型3类,结合创新企业数据、POI数据和统计年鉴等数据类型,通过核密度估计、DBsCAN聚类算法以及mGWR模型等方法,刻... 详细信息

作为创新活动的重要载体,创新空间是近年来创新地理学领域关注的重点内容。文章将深圳市创新空间划分技术型、知识型和孵化型3类,结合创新企业数据、POI数据和统计年鉴等数据类型,通过核密度估计、DBsCAN聚类算法以及mGWR模型等方法,刻画创新空间的结构特征、各自异同点及其影响因素。研究发现:①深圳市技术型、知识型和孵化型创新空间均表现为“中心—外围”圈层特点,其中,技术型创新空间还具有等级性组团结构特征;②地区创新水平、产业园支持、金融咨询服务、交通发达程度以及某些生活服务和公共服务会显著正向促进创新空间集聚,但综合型创新核心区、专业型创新发展区和潜力型创新成长区受到的影响具有差异性。基于研究结论,文章针对性地提出了优化深圳市创新空间的政策建议,以期为城市创新空间的优化提供依据。

关键词：创新空间结构特征影响因素 DBsCAN空间聚类 mGWR

The effect of non-pharmaceutical interventions on COVID-19 outcomes:A heterogeneous age-related generalisation of the sEIR model

在线全文

学校读者我要写书评

暂无评论

Infectious Disease modelling 2023年第3期8卷 742-768页

作者： Jorge m.mendes Pedro s.Coelho NOVA Information m.nagement school(NOVAIms) Universidade Nova de LisboaCampus de Campolide1070-312LisbonPortugal NOVA Cairo at the Knowledge Hub Universities New Admnistrative CapitalCairoEgypt

successive generalisations of the basic sEIR model have been proposed to accommodate the different needs of the organisations handling the sARs-CoV-2 epidemic and the assessment of the public health measures adopted and named under the common um-brella of Non-Pharmaceutical Interventions(NPIs).so far,these generalisations have not been able to assess the ability of these measures to avoid infection by the sARs-CoV-2 and thus their contribution to contain the spread of the *** work proposes a new generalisation of sEIR model and includes a heterogeneous and age-related generation of infections that depends both on a probability that a contact generates the transmission of the disease and a contact *** results show(1)thanks to the universal wearing of facial coverings,the probability that a contact provokes the transmission of the disease was reduced by at least 50%and(2)the impact of the other NPI is so significant that otherwise Portugal would have gone into a non-sustainable situation of having 80%of its population infected in the first 300 days of the *** situation would have led to a number of deaths almost twenty times higher than the number that was actually recorded by December 26th,***,the results suggest that even if the requirement of universal wearing of facial coverings was adopted sooner jointly with closing workplaces and resorting to teleworking would have postponed the peak of the incidence,altought the epidemic path would have result in a number of infections hardly m.naged by the national Health ***,results confirm that(3)the health authorities adopted a conservative approach on the criteria to consider an infected individual not infective any longer;and(4)the most effective NPIs and stringency levels either impacting on self-protection against infection or reducing the contacts that would eventually result in infection are,in decreasing order of importance,the use of Facial coverings,Workplace clos

关键词： eventually otherwise string

3D finite element analysis of the residual stresses in butt-welded plates with modeling of the electrode-movement

维普期刊数据库评论

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 Zhejiang University-science A(Applied Physics & Engineering) 2009年第1期10卷 37-43页

作者： F.VAKILI-TAHAmI A.H.DAEI-sORKHABI m.A.sAEImI-s A.HOmAYOUNFAR Department of mechanical Engineering University of Tabriz Department of mechanical Engineering Islamic Azad University-Tabriz Branch

In this paper the residual stresses in a butt-welded plate of 2.25Cr 1mo has been analyzed using a 3D and transient finite element (FE) *** the effect of the welding-electrode speed has been studied using death and birth of *** this purpose,a coupled thermo-mechanical FE solution has been used to obtain the temperature distribution and the resulting residual ***,the variations of the physical properties of the material with temperature have been taken into *** show that the residual stresses in the heat affected zone (HAZ) are maximum and change along the weld and also in the *** has been shown that use of the 3D and transient model will lead to more accurate and realistic results which are well compared with the experimental test data.

关键词： Finite element (FE) Residual stresses Weldment 2.25Cr Imo steel

Geospatial mapping of soil Nitrate-Nitrogen Distribution Under a mixed-Land Use system

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第4期19卷 434-445页

作者： s. LAmsAL C. m. BLIss D. A. GRAETZ school of Forest Resources and Conservation University of Florida UsDA Forest service Southern Research Station soil and Water science Department University of Florida

mapping the spatial distribution of soil nitrate-nitrogen （NO3=N） is important to guide nitrogen application as well as to assess environmental risk of NO3-N leaching into the groundwater. We employed univariate and hybrid geostatistical methods to map the spatial distribution of soil NO3-N across a landscape in northeast Florida. soil samples were collected from four depth increments （0-30, 30-60, 60-120 and 120-180 cm） from 147 sampling locations identified using a stratified random and nested sampling design based on soil, land use and elevation strata. soil NO3-N distributions in the top two layers were spatially autocorrelated and mapped using lognormal kriging. Environmental correlation models for NO3-N prediction were derived using linear and non-linear regression methods, and employed to develop NO3-N trend maps. Land use and its related variables derived from satellite imagery were identified as important variables to predict NO3-N using environmental correlation models. While lognormal kriging produced smoothly varying maps, trend maps derived from environmental correlation models generated spatially heterogeneous maps. Trend maps were combined with ordinary kriging predictions of trend model residuals to develop regression kriging prediction maps, which gave the best NO3-N predictions. As land use and remotely sensed data are readily available and have much finer spatial resolution compared to field sampled soils, our findings suggested the efficacy of environmental correlation models based on land use and remotely sensed data for landscape scale mapping of soil NO3-N. The methodologies implemented are transferable for mapping of soil NO3-N in other landscapes.

关键词： environmental correlation general linear model kriging land use regression