检索结果-南通市图书馆

The Full Multi-wake Vortex Lattice Method:a detached flow model based on Potential Flow Theory

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Aerodynamics 2023年第1期5卷 452-477页

作者： jesus carlos Pimentel-Garcia The School of Industrial Aerospace and Audiovisual Engineering of Terrassa(ESEIAAT)Polytechnic University of CataloniaTerrassa 08222Spain

One of the main issues concerning the standard Vortex Lattice Method is its application to partially or fully detached flow conditions,where non-linear aerodynamic characteristics appear as the angle of attack increases and/or the aspect ratio *** order to solve such limitations,a pure numerical approach based entirely on the Vortex Lattice Method concepts has been *** so-called steady“Full Multi-wake Vortex Lattice Method”comes from the main hypothesis that each discretized element on the body’s surface detaches their own wakes *** obtained results match for lift,drag and moment coefficients for the entire aspect ratio range configurations(under straight wakes and inviscid assumptions).Future unsteady versions of such a multi-wake approach could improve the current results obtained through Vortex Element Methods(as vortons or isolated vortex filaments).

关键词： Potential Flow Theory Ideal flow Detached flow Vorticity generation Vortex Lattice Method Kutta condition

Gone with the wind： Seasonal trends in foraging movement directions for a central-place forager

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2014年第5期60卷 604-615页

作者： jesus HERNANDEZ-PLIEGO carlos RODRIGUEZ Javier BUSTAMANTE Department of Wetland Ecology Estacion Biologica de Dofiana CSIC c/Amorico Vespucio s/n 41092 Seville Spain Department of Conservation Biology Estacion Biologica de Dofiana C SIC c/Amorico Vespucio s/n 41092 Seville Spain

Lesser kestrels Falco naumanni are migratory central-place foragers that breed in dynamic arable landscapes. After arriving from migration, kestrels have no knowledge of the distribution of crops, and consequently prey, around their colony. The energy demand of pairs increases as breeding season progresses, but at the same time prey abundance, and their knowledge on prey distribution, also increases. Wind can have a strong influence on flight cost and kestrels should try to reduce energy expendi- ture when possible. When prey abundance is low, kestrels have little knowledge of prey distribution, and pairs have no chicks, they could reduce foraging flight cost by leaving the colony with tailwinds. When prey is abundant, knowledge on prey distribu- tion has increased, and chick demand is high, kestrels should fly to the most favorable foraging patches. We analyzed foraging trips directions in a lesser kestrel colony along the breeding season and in relation to wind speed and direction. We recorded 664 foraging trips from 19 individuals using GPS-dataloggers. We found that outward flights direction changed from uniform to a concentrated distribution along the season, as prey abundance and individual experience increased. We also found a temporal trend in the angular difference between outward flights and wind directions, with low values early in the season and then increa- sing as expected, but again low values at the end, contrary to expectation. Results suggest changes in kestrels foraging strategy along the season in relation to wind. Kestrels depart more with tailwinds in exploratory flights early in the season, while there is a spurious coincidence in direction to preferred foraging patches and dominant wind direction at the end [Current Zoology 60 （5）： 604-615, 2014].

关键词： Falco naumanni Movement ecology Foraging behavior Wind effect GPS-dataloggers

Contrasted Impact of Land Abandonment on Soil Erosion in Mediterranean Agriculture Fields

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2018年第4期28卷 617-631页

作者： jesus RODRIGO-COMINO carlos MARTINEZ-HERNANDEZ Thomas ISERLOH Artemi CERDA Instituto de Geomorfología y Suelos Department of Geography University of Málaga Mdlaga 29071 (Spain) Department of Physical Geography Trier University Trier 54286 (Germany) Department of Geography University of Murcia Murcia 30001 (Spain) Soil Erosion and Degradation Research Group Department of Geography University of Valencia Valencia 46010 (Spain)

Abandonment of agricultural land results in on- and off-site consequences for the ecosystem. In this study, 105 rainfall simulations were carried out in agriculture lands of the Mediterranean belt in Spain （vineyards in Malaga, almond orchards in Murcia, and orange and olive orchards in Valencia） and in paired abandoned lands to assess the impact of land abandonment on soil and water losses. After abandonment, soil detachment decreased drastically in the olive and orange orchards, while vineyards did not show any difference and almond orchards registered higher erosion rates after the abandonment. Terraced orchards of oranges and olives recovered a dense vegetation cover after the abandonment, while the sloping terrain of almond orchards and vineyards enhanced the development of crusts and rills and a negligible vegetation cover resulted in high erosion rates. The contrasted responses to land abandonment in Mediterranean agricultural lands suggest that land abandonment should be programmed and managed with soil erosion control strategies for some years to avoid land degradation.

关键词： erosion rate Mediterranean crop rainfall simulation terrace vegetation cover

Influence of V(C,N) Precipitates on Microstructure and Mechanical Properties of Continuous Cooled C-Mn-V

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 266-270页

作者： carlos Garcia-Mateo carlos Capdevila Juan Cornide jesus Chao Francisca G Caballero carlos Garcia de Andres Materalia Research Group Department of Physical Metallurgy Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC)Avda.Gregorio del Amo8 E-28040 MadridSpain

The effect of chemical composition and processing parameters on the formation of acicular ferrite and/or bainite has been *** particular,this paper deals with the influence that N through its combination with V,as V(C,N) precipitates,has on the decomposition of ***,the intragranular nucleation potency of V(C,N) precipitates is analyzed through the continuous cooling transformation diagrams (CCT) of two C-Mn-V steels with different contents of *** reported in this work allow us to conclude that acicular ferrite can only be achieved alloying with vanadium and nitrogen,meanwhile bainite is promoted in steels with a low level of *** is concluded that higher strength values are obtained in acicular ferrite than in bainitic steel but a similar brittle-ductile transition temperature (BDT),and lower values of impact absorbed energy (KV) has been recorded in nitrogen-rich steel.

关键词： acicular ferrite bainite vanadium precipitates mechanical properties

A comparative study of the morphometry of sperm head components in cattle, sheep, and pigs with a computer-assisted fluorescence method

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2016年第6期18卷 840-843页

作者： jesus L Yaniz Sara Capistros Sandra Vicente-Fiel carlos O Hidalgo Pilar Santolaria TECNOGAM research group Environmental Sciences Institute (IUCA) Department of Animal Production and Food Sciences University of Zaragoza Huesca Spain Animal Genetics and Reproduction Area Regional Agrifood Research and Development Service (SERIDA) 33394 Deva Gijan Spain

The aim of this study was to compare the sperm nuclear and acrosomal morphometry of three species of domestic artiodactyls; cattle （Bos taurus）, sheep （Ovis aries）, and pigs （Sus scrofa）. Semen smears of twenty ejaculates from each species were fixed and labeled with a propidium iodide-Pisum sativum agglutinin （PI/PSA） combination. Digital images of the sperm nucleus, acrosome, and whole sperm head were captured and analyzed. The use of the PI/PSA combination and CASA-Morph fluorescence-based method allowed the capture, morphometric analysis, and differentiation of most sperm nuclei, acrosomes and whole heads, and the assessment of acrosomal integrity with a high precision in the three species studied. For the size of the head and nuclear area, the relationship between the three species may be summarized as bull 〉 ram 〉 boar. However, for the other morphometric parameters （length, width, and perimeter）, there were differences in the relationships between species for sperm nuclei and whole sperm heads. Bull sperm acrosomes were clearly smaller than those in the other species studied and covered a smaller proportion of the sperm head. The acrosomal morphology, small in the bull, large and broad in the sheep, and large, long, and with a pronounced equatorial segment curve in the boar, was species-characteristic. It was concluded that there are clear variations in the size and shape of the sperm head components between the three species studied, the acrosome being the structure showing the most variability, allowing a clear distinction of the spermatozoa of each species.

关键词： artiodactyls computer-assisted sperm morphometry analysis fluorescence microscopy image analysis sperm morphometry

Shear-flexural strength mechanical model for the design and assessment of reinforced concrete beams subjected to point or distributed loads

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2014年第4期8卷 337-353页

作者： Antonio MAIRI Antoni CLADERA jesus BAIRAN Eva OLLER carlos RIBAS Department of Construction Engineering Universitat Politecnica de Catalunya Barcelona 08034 Spain Department of Physics University of Balearic Islands Palma de Mallorca Spain

A mechanical model recently developed for the shear strength of slender reinforced concrete beams with and without shear reinforcement is presented and extended to elements with uniformly distributed loads, specially focusing on practical design and assessment in this paper. The shear strength is considered to be the sum of the shear transferred by the concrete compression chord, along the crack, due to residual tensile and frictional stresses, by the stirrups and, if they exist, by the longitudinal reinforcement. Based on the principles of structural mechanics simple expressions have been derived separately for each shear transfer action and for their interaction at ultimate limit state. The predictions of the model have been compared to those obtained by using the EC2, MC2010 and ACI 318-08 provisions and they fit very well the available experimental results from the recently published ACI-DAfStb databases of shear tests on slender reinforced concrete beams with and without stirrups. Finally, a detailed application example has been presented, obtaining each contributing component to the shear strength and the assumed shape and position of the critical crack.

关键词： shear strength mechanical model reinforced concrete design assessment shear tests

Web Application Commercial Design for Financial Entities Based on Business Intelligence

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第6期67卷 3177-3188页

作者： carlos Andrés Tavera Romero jesus Hamilton Ortiz Osamah Ibrahim Khalaf Andrea Ríos Prado COMBA I+D Research Group of Universidad Santiago de Cali Valle del CaucaColombia Closemobile R&D Telecommunications LS FuenlabradaEspaña Al-Nahrain Nanorenewable Energy Research Center in Al-Nahrain University BagdadIraq

Multiple customer data management has become a focus of attention in big *** much information is available,it does not translate into significant profitable value-added *** present a design of a commercial web application based on business intelligence that generates information on social and financial behavior of clients in an organization;with the purpose of obtain additional information that allows to get more *** app will provide a broader perspective for making strategic decisions to increase profits and reduce internal investment costs.A case in point is the financial sector,a group of financial entities were used to make measurements and test them.A design to build a web application aimed at achieving a large and ambitious goal by means of defined tools reflecting clients’business needs is *** this research,different techniques and technologies are explored,such as diagrams,frameworks,design,architecture,model entity-relationship,tables,equations,mental maps and development *** the Personal Software Process methodology and with the help of information extraction,consolidation,and visualization,the implementation can be carried *** article provides the importance of implementing business intelligence in an organization and expands on the steps needed for the implementation of this valuable technology.

关键词： Business intelligence banking application web application trend analysis decision making

Biochar and sugar cane filter cake interaction on physical and hydrological soil properties under tropical field conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biochar 2020年第2期2卷 195-210页

作者： Sara de jesus Duarte Bruno Glaser Blanca Lucia Prado Pano carlos Eduardo Pellegrino Cerri Soil and Plant Nutrition Luiz de Queiroz College of AgricultureUniversity of São PauloAvenida Pádua Dias11-AgronomiaPiracicabaSP 13418-900Brazil Soil Biogeochemistry Martin Luther University Halle-WittenbergVon-Seckendorff-Platz 306120 HalleGermany Instituto de Geología Universidad Nacional Autónoma de MéxicoMéxicoD.F.Mexico

Biochar is known for its effects on carbon sequestration and soil ***,there is a lack of information about its effects on soil physical and hydraulic properties for tropical *** assessed the effects of biochar(BC)plus sugar cane filter cake(FC)rate,and time of interaction on soil physical and hydraulic properties under humid tropical *** this purpose,a field experiment was installed at a loamy sandy soil with five treatments and four replicates:control(only soil),25 Mg ha^(−1) sugar cane filter cake,and 25 Mg ha^(−1) sugar cane filter cake plus 6.25,12.5,and 25 Mg ha^(−1) Miscanthus biochar,respectively,two soil depths(0-10 and 10-20 cm)and two times of interaction(9 and 18 months).Physical prop-erties(aggregate stability,bulk density,total porosity,pores size distribution)and hydraulic properties(soil water holding capacity,hydraulic conductivity,plant-available water holding capacity)were measured after nine and eighteen *** bulk density decreased slightly,and the porosity increased after nine months,for the biochar plus sugar cane filter cake(both 25 Mg ha^(−1)).After 18 months,biochar plus filter cake interaction increase micropores,aggregate stability,and plant-available water *** hydraulic conductivity was not influenced by sugar cane filter ***,biochar significantly reduced saturated hydraulic conductivity when combined with sugar cane filter cake after 18 *** concluded that sugar cane filter cake in combination with biochar modified the pore size distribution,slightly increased plant-available water holding capacity,and significantly decreased saturated hydraulic conductivity.

关键词： Water retention Hydraulic conductivity Miscanthus biochar Soil physics

Relationship of sperm plasma membrane andacrosomal integrities with sperm morphometry inBos taurus

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2020年第6期22卷 578-582页

作者： Inmaculada Palacin Pilar Santolaria carlos Alquezar-Baeta Carles Soler Miguel A Silvestre jesus Yaniz BIOFITER Research Group Environmental Sciences Institute(IUCA)Department of Animal Production and Food SciencesUniversity of ZaragozaHuesca 22071Spain Department of Computer Science University of ZaragozaZaragoza 50018Spain Department of Cellular Biology Functional Biology and Physical AnthropologyUniversity of ValenciaBurjassot 46100Spain

To date,sperm morphometric studies have assessed whole sperm populations without considering sperm *** aim of this study was to evaluate the relati on ship of sperm membrane and acrosomal integrity with sperm morphometry in liquid semen samples collected from *** this end,sperm morphometry was performed on cryopreserved semen samples from 16 bulls by a combination of fluorescent dyes,including Hoechst 33343,carboxyfluorescein diacetate,and propidium *** allowed discrimination of different subpopulations on the basis of sperm membrane and acrosomal integrity and analysis of the morphometries of the sperm head,nucleus,and acrosome using a specific plug-in module created on *** integrity was related to sperm morphometry as the heads of spermatozoa with a damaged acrosome were significantly smaller than those with a normal acrosome(P<0.001).In the case of spermatozoa with an intact acrosome,those with a damaged plasma membrane had a larger sperm head and acrosome than spermatozoa with an intact plasma membrane(P<0.001).No significant differences in the sperm head size were observed between sperm subpopulations without an acrosome or in the nuclear sperm morphometry of the different *** was a positive correlation between the sperm motility values of the samples and the morphometric parameters for in tact *** correlations were particularly strong for the morphometric parameters of the sperm *** conclude that there are clear differences in the sperm morphometry depending on the status of the sperm membrane and acrosome and this should be considered when performing this kind of analysis.

关键词： Bos taurus fluoresce nee microscopy image analysis sperm morphometry sperm quality