检索结果-南通市图书馆

High-resolution flood modeling of urban areas using MSN_Flood

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2017年第3期10卷 175-183页

作者： Michael Hartnett stephen nash Department of Civil Engineering National University of IrelandGalwayIreland

Although existing hydraulic models have been used to simulate and predict urban flooding, most of these models are inadequate due to the high spatial resolution required to simulate flows in urban floodplains. Nesting high-resolution subdomains within coarser-resolution models is an efficient solution for enabling simultaneous calculation of flooding due to tides, surges, and high river flows. MSN_Flood has been developed to incorporate moving boundaries around nested domains, permitting alternate flooding and drying along the boundary and in the interior of the domain. Ghost cells adjacent to open boundary cells convert open boundaries, in effect, into internal boundaries. The moving boundary may be multi-segmented and non-continuous, with recirculating flow across the boundary. When combined with a bespoke adaptive interpolation scheme, this approach facilitates a dynamic internal boundary. Based on an alternating-direction semi-implicit finite difference scheme,MSN_Flood was used to hindcast a major flood event in Cork City resulting from the combined pressures of fluvial, tidal, and storm surge processes. The results show that the model is computationally efficient, as the 2-m high-resolution nest is used only in the urban flooded ***, lower-resolution nests are used. The results also show that the model is highly accurate when compared with measured data. The model is capable of incorporating nested sub-domains when the nested boundary is multi-segmented and highly complex with lateral gradients of elevation and velocities. This is a major benefit when modelling urban floodplains at very high resolution.

关键词： Multi-scale nesting Surge-fluvial flooding Urban flooding Multi-segmented boundary Moving boundary

Observation and modeling of tide- and wind-induced surface currents in Galway Bay

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2015年第4期8卷 345-352页

作者： Lei Ren stephen nash Michael Hartnett Department of Civil Engineering College of Engineering and Informatics National University of Ireland

A high-frequency radar system has been deployed in Galway Bay, a semi-enclosed bay on the west coast of Ireland. The system provides surface currents with fine spatial resolution every hour. Prior to its use for model validation, the accuracy of the radar data was verified through comparison with measurements from acoustic Doppler current profilers （ADCPs） and a good correlation between time series of surface current speeds and directions obtained from radar data and ADCP data. Since Galway Bay is located on the coast of the Atlantic Ocean, it is subject to relatively windy conditions, and surface currents are therefore strongly wind-driven. With a view to assimilating the radar data for forecasting purposes, a three-dimensional numerical model of Galway Bay, the Environmental Fluid Dynamics Code （EFDC）, was developed based on a terrain-following vertical （sigma） coordinate system. This study shows that the performance and accuracy of the numerical model, particularly with regard to tide- and wind-induced surface currents, are sensitive to the vertical layer structure. Results of five models with different layer structures are presented and compared with radar measurements. A variable vertical structure with thin layers at the bottom and the surface and thicker layers in the middle of the water column was found to be the optimal layer structure for reproduction of tideand wind-induced surface currents. This structure ensures that wind shear can properly propagate from the surface layer to the sub-surface layers, thereby ensuring that wind forcing is not overdamped by tidal forcing. The vertical layer structure affects not only the velocities at the surface layer but also the velocities further down in the water column.

关键词： Wind-induced surface current Vertical layer structure High-frequency radar Coastal ocean dynamics application radar Environmental fluid dynamicscode Galway Bay

Truncated Newton-Based Multigrid Algorithm for Centroidal Voronoi Diagram Calculation

在线全文

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2012年第2期5卷 242-259页

作者： Zichao Di Maria Emelianenko stephen nash Department of Mathematical Sciences George Mason UniversityFairfaxVA 22030USA. Systems Engineering and Operations Research Department George Mason UniversityFairfaxVA 22030USA

In a variety of modern applications there arises a need to tessellate the domain into representative regions,called Voronoi cells.A particular type of such tessellations,called centroidal Voronoi tessellations or CVTs,are in big demand due to their optimality properties important for many *** availability of fast and reliable algorithms for their construction is crucial for their successful use in practical *** paper introduces a new multigrid algorithm for constructing CVTs that is based on the MG/Opt algorithm that was originally designed to solve large nonlinear optimization *** convergence of the new method and its speedup comparing to existing techniques are demonstrated for linear and nonlinear densities for several 1d and 2d problems,and O(k)complexity estimation is provided for a problem with k generators.

关键词： Centroidal Voronoi tessellation optimal quantization truncated Newton method Lloyd’s algorithm multilevel method uniform convergence

The GBR Hypothesis Revisited

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 High Energy Physics, Gravitation and Cosmology 2024年第2期10卷 800-809页

作者： Lewis nash Marrietta GA USA

The radical hypothesis concerning the physics of gravitational black-body radiation is placed on a more solid statistical mechanics foundation in this study. As the concepts and formalism in the former presentation are only partially developed and furthermore, suffer from an unfortunate misstep regarding Hawking radiation and the hypothetical gravitational black-body temperature of a parcel or distribution of energy;this paper aims to fill in some of the theoretical gaps in the derivation of the Planck radiation formula for gravity (or non-Euclidean space-time), and there by provide a more complete and transparent quantum theory of thermal gravitational radiation.

关键词： Gravitational Black Body Gravitons Thermal Gravitational Radiation Spiral Galaxy Rotation Curves

Curved Space-Time at the Planck Scale

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 High Energy Physics, Gravitation and Cosmology 2024年第1期10卷 167-179页

作者： Lewis nash Marietta GA USA

This paper presents a physically plausible and somewhat illuminating first step in extending the fundamental principles of mechanical stress and strain to space-time. Here the geometry of space-time, encoded in the metric tensor, is considered to be made up of a dynamic lattice of extremely small, localized fields that form a perfectly elastic Lorentz symmetric space-time at the global (macroscopic) scale. This theoretical model of space-time at the Planck scale leads to a somewhat surprising result in which matter waves in curved space-time radiate thermal gravitational energy, as well as an equally intriguing relationship for the anomalous dispersion of light in a gravitational field.

关键词： Schwarzschild Space-Time Continuum Mechanics Planck Lattice Gravitational Radiation

Ancient DNA of the pygmy marmoset type specimen Cebuella pygmaea(Spix,1823)resolves a taxonomic conundrum

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Zoological Research 2021年第6期42卷 761-771页

作者： Jean P.Boubli Mareike C.Janiak Leila M.Porter Stella de la Torre Liliana Cortes-Ortiz Maria N.Fda Silva Anthony B.Rylands stephen nash Fabricio Bertuol Hazel Byrne Felipe E.Silva Fabio Rohe Dorien de Vries Robin M.D.Beck Irune Ruiz-Gartzia Lukas F.K.Kuderna Tomas Marques-Bonet Tomas Hrbek Izeni P.Farias Anneke Hvan Heteren Christian Roos School of Science Engineering&EnvironmentUniversity of SalfordSalford M54WTUK Instituto Nacional de Pesquisas da Amazonia ManausAmazonas 69060-001Brazil Department of Anthropology Northern Illinois UniversityDeKalbIL 60115-2828USA College of Biological and Environmental Sciences Universidad San Francisco de QuitoQuito 170901Ecuador Department of Ecology and Evolutionary Biology University of MichiganAnn ArborMI 48109USA Re:wild AustinTX 78767USA Laboratorio de Evolução e Genética Animal Universidade Federal do AmazonasManausAmazonas 69080-900Brazil Department of Anthropology University of UtahSalt Lake CityUT 84112USA Research Group on Primate Biology and Conservation MamirauaInstitute for Sustainable DevelopmentTeféAmazonas 69553-225Brazil Experimental and Health Sciences Department(DCEXS) Institut de Biologia EvolutivaUniversitat Pompeu Fabra-CSICBarcelona 08002Spain Department of Biology Trinity UniversitySan AntonioTX 78212USA Bavarian State Collection of Zoology Zoologische Staatssammlung MünchenStaatliche Naturkundliche Sammlungen Bayerns81247 MunichGermany GeoBio-Center Ludwig-Maximilians-Universitat München80333 MunichGermany Department Biologie II Ludwig-Maximilians-Universitat München82152 MunichGermany Gene Bank of Primates and Primate Genetics Laboratory German Primate CenterLeibniz Institute for Primate Research37077 GottingenGermany

The pygmy marmoset,the smallest of the anthropoid primates,has a broad distribution in Western *** studies using molecular and morphological data have identified two distinct species separated by the Napo and Solimoes-Amazonas ***,reconciling this new biological evidence with current taxonomy,i.e.,two subspecies,Cebuella pygmaea pygmaea(Spix,1823)and Cebuella pygmaea niveiventris(Lönnberg,1940),was problematic given the uncertainty as to whether Spix’s pygmy marmoset(Cebuella pygmaea pygmaea)was collected north or south of the Napo and Solimoes-Amazonas rivers,making it unclear to which of the two newly revealed species the name pygmaea would ***,we present the first molecular data from Spix’s type specimen of Cebuella pygmaea,as well as novel mitochondrial genomes from modern pygmy marmosets sampled near the type locality(Tabatinga)on both sides of the *** these data,we can confirm the correct names of the two species identified,i.e.,*** for animals north of the Napo and Solimoes-Amazonas rivers and *** for animals south of these two *** analyses of the novel genetic data placed into the context of cytochrome b gene sequences from across the range of pygmy marmosets further led us to reevaluate the geographical distribution for the two Cebuella *** dated the split of these two species to 2.54 million years *** discuss additional,more recent,subdivisions within each lineage,as well as potential contact zones between the two species in the headwaters of these rivers.

关键词： Historic DNA DNA taxonomy Pygmy marmoset Cebuella pygmaea C.niveiventris Amazon Type specimen

Publisher’s Erratum to:Metamaterial-based graphene thermal emitter

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 5753-5753页

作者： Cheng Shi Nathan H.Mahlmeister Isaac J.Luxmoore Geoffrey R.nash College of Engineering Mathematics and Physical SciencesUniversity of ExeterExeterEX44QFUK

The article"Metamaterial-based graphene thermal emitter",written by Cheng Shi,Nathan ***,***,and Geoffrey ***,was originally published electronically on the publisher’s internet portal(currently SpringerLink)on December 6th 2017 without open *** the author(s)’decision to opt for Open Choice the copyright of the article changed in February 2018 to©The Author(s)2018 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License(http://***/licenses/by/4.0/),which permits use,duplication,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons license and indicate if changes were *** original article has been corrected.

关键词： emitter license creative

A young man presenting with persistent hypoglycaemia and reduced level of consciousness: case study with review of literature

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2022年第5期13卷 418-421页

作者： Meher Khan Nadia Kathrada Dean nash Debkumar Chowdhury Critical Care Unit Royal Blackburn HospitalBlackburnBB23HHUnited Kingdom

Dear editor,Iatrogenic hypoglycaemia is a common acute presentation;either because of misuse,self-harm or criminal *** most common culprits are insulin and oral hypoglycaemics(sulfonylurea,biguanides)although aspirin,fluoroquinolone and beta blockers can be causative *** symptoms include sweating,anxiety,tremors,and *** symptoms usually arise at serum glucose concentrations of<2.8 mmol/L and include dizziness,confusion,blurred vision,somnolence and more serious symptoms can be convulsions,coma and potentially death.

关键词： acute editor tremor

Dynamic phase transition behavior of a LiMn_(0.5)Fe_(0.5)PO_(4) olivine cathode material for lithium-ion batteries revealed through in-situ X-ray techniques

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第8期31卷 452-459,I0012页

作者： Sujeera Pleuksachat Phongsit Krabao Sarawut Pongha Viyada Harnchana Pawinee Klangtakai Wanwisa Limphirat Siriwat Soontaranon Jeffrey nash Nonglak Meethong Department of Physics Faculty of ScienceKhon Kaen UniversityKhon Kaen 40002Thailand Institute of Nanomaterials Research and Innovation for Energy(IN-RIE) Research Network of NANOTEC-KKU(RNN)Khon Kaen UniversityKhon Kaen 40002Thailand Synchrotron Light Research Institute(SLRI) Nakhon Ratchasima 30000Thailand

LiMn_(0.5)Fe_(0.5)PO_(4) has attracted great interest due to its good electrochemical performance and higher operating *** has led to a greater than 30 percent higher energy density than for commercial Li Fe PO4 olivine *** the phase transition behaviors and kinetics of this material will help researchers to design and develop next generation cathodes for Li-ion *** this study,we investigated non-equilibrium phase transition behaviors in a LiMn_(0.5)Fe_(0.5)PO_(4) cathode material during charge–discharge processes by varying current rates(C-rates)using synchrotron in-situ X-ray *** methods included wide angle X-ray scattering(in-situ WAXS)and X-ray absorption spectroscopy(in-situ XAS).The WAXS spectra indicate that the phase transition of LiMn_(0.5)Fe_(0.5)PO_(4) material at slow C-rates is induced by a two-phase *** contrast,at a high C-rate(5 C),the formation of an intermediate phase upon discharge is clearly ***,the oxidation numbers of the redox reactions of Fe^(2+)/Fe^(3+)and Mn^(2+)/Mn^(3+)were evaluated using in-situ *** combination of synchrotron in-situ X-ray techniques gives clear insights into the non-equilibrium phase transition behavior of a LiMn_(0.5)Fe_(0.5)PO_(4) cathode *** new understanding will be useful for further developments of this highly promising cathode material for practical commercialization.

关键词： LiMn_(0.5)Fe_(0.5)PO_(4) Phase transition In-situ X-ray techniques