检索结果-南通市图书馆

Quasi-Lagrangian Acceleration of Eulerian Methods

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2009年第9期6卷 743-757页

作者： igor Kliakhandler Alexander Kurganov Department of Mathematical Sciences Michigan Technological UniversityHoughtonMI 49931USA Mathematics Department Tulane UniversityNew OrleansLA 70118USA

We present a simple and efficient strategy for the acceleration of explicit Eulerian methods for multidimensional hyperbolic systems of conservation *** strategy is based on the Galilean invariance of dynamic equations and optimization of the reference frame,in which the equations are numerically *** optimal reference frame moves(locally in time)with the average characteristic speed of the system,and,in this sense,the resulting method is *** leads to the acceleration of the numerical computations thanks to the optimal CFL condition and automatic adjustment of the computational domain to the evolving part of the *** show that our quasi-Lagrangian acceleration procedure may also reduce the numerical dissipation of the underlying Eulerian *** leads to a significantly enhanced resolution,especially in the supersonic *** demonstrate a great potential of the proposed method on a number of numerical examples.

关键词： Eulerian methods quasi-Lagrangian method finite volume methods Galilean invariance

Modeling of ice-Water Phase Change in Horizontal Annulus Using Modified Enthalpy Method

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 Applied Mathematics and Mechanics 2011年第3期3卷 354-369页

作者： Esad Tombarevic igor Vusanovic Faculty of Mechanical Engineering University of MontenegroCetinjski put bb81000 PodgoricaMontenegro

Phase change in ice-water systems in the geometry of horizontal cylindrical annulus with constant inner wall temperature and adiabatic outer wall is modeled with an enthalpy-based mixture *** and melting phenomena under different temperature conditions are analyzed through a sequence of numerical *** the case of freezing of water,the importance of convection and conduction as well as the influence of cold pipe temperature on time for the complete solidification are *** for the case of melting of ice,the influence of the inner pipe wall temperature on the shape of the ice-water interface,the flow and temperature fields in the liquid,the heat transfer coefficients and the rate of melting are *** results of numerical calculations point to good qualitative agreement with the available experimental and other numerical results.

关键词： Phase change solidification melting enthalpy model fixed grid annulus

inhaled nicotine replacement therapy

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 Pharmaceutical Sciences 2015年第6期10卷 472-480页

作者： David Cipolla igor Gonda Aradigm Corp 3929 Point EdenWayHaywardCA 94545USA

There are a large number of smokers who want to quit smoking but have failed in their attempts to do so,with many having been unsuccessful at quitting multiple times over their *** existing marketed nicotine replacement therapies(NRT)have only marginal effectiveness and none provide a comparable physiological response to that derived from cigarette smoking;that is,rapid absorption of nicotine from the lung leading to peak levels of nicotine in the bloodstream to target the receptors in the ***,existing NRTs produce a slower and delayed rise in nicotine blood levels which is less effective at reducing the craving *** data for electronic cigarettes show that they typically deliver nicotine with a profile closer to that for nicotine patches,with a slow rise that can take 30–60 min,or longer,to reach the same peak nicotine concentration that is produced in less than 3 min from a single cigarette.A number of attempts have been made to develop an inhaled product which would deliver the nicotine through the lung and mimic the physiological response from smoking,but many of them produced intolerable aversive reactions or delivered an ineffective *** paper discusses examples of the potential for the recent inhaled nicotine products in development to be effective as NRTs,but is not meant to be a comprehensive review.

关键词： Nicotine Smoking cessation inhalation delivery AERx system Staccato Voke inhaler

Determining effects of impact loading on residual strength of fiber-metal laminates with grid-characteristic numerical method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第7期34卷 1-12页

作者： Katerina BEKLEMYSHEVA Vasily GOLUBEV igor PETROV Alexey VASYUKOV Moscow institute of Physics and Technology DolgoprudniyRussia

The Grid-Characteristic numerical Method(GCM)that is quite common in solving aero and hydrodynamic problems can also be applied for mechanics of *** allows to implement complex border and contact conditions,including the non-reflecting border and the destructible *** this conditions are very important for the precise and effective modeling of LowVelocity impacts(LVi)on fiber and Fiber-Metal Laminates(FML)and the resulting Barely Visible impact Damage(BViD)that influences the residual strength of a composite aircraft *** is the type of damage that is not visible by the naked eye and can be hardly detected by a standard ultrasound equipment that is used for regular *** can appear during any weak impacts like bird strike or *** its influence on the residual strength of the part is very important to define the priorities of development of ultrasound *** this paper,the GCM was applied for a full cycle of loading of an FML aircraft cover *** FML consisted of a Carbon Fiber Reinforced Polymer(CFRP)and a single titanium layer on the upper *** cycle of loading in a single calculation consisted of an LVi caused by a small striker and a comparatively slow compressive in-plane ***-dimensional patterns of velocity and stress distributions over the time of calculation are *** patterns,obtained via the Hashin failure criterion are given and analyzed.

关键词： Fiber-metal laminate Grid-characteristic method Low-velocity impact Numerical modeling Residual strength

Clustering and precipitation in Al-Mg-Si alloys during linear heating

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 Materials Science & Technology 2022年第25期120卷 78-88页

作者： Zi Yang igor Erdle Chunhui Liu John Banhart Helmholtz-Centre Berlin for Materials and Energy Hahn-Meitner-Platz 1Berlin 14109Germany State Key Laboratory of High-Performance Complex Manufacturing Central South UniversityChangsha 410083China

Differential scanning calorimetry(DSC) is a technique extensively applied to analyse precipitation phenomena in Al-Mg-Si alloys, yet the processes occurring during non-isothermal DSC heating, in particular the formation of clusters in the early stage and their evolution at higher temperatures, remain obscure. Here, we carry out experiments not only to measure heat(via DSC) but also to measure hardness,positron lifetime, electrical resistivity and microstructure of an Al-Mg-Si alloy heated at 3 different *** resistivity is measured in situ, the other properties after interrupting the heating process. it is demonstrated that the precipitation process during heating can be divided into various stages, with transition temperatures depending on the heating rate, but the relative behavior of the various measured quantities is connected in the same way. Quenched-in excess vacancies are found to play an important role in cluster formation at lower temperatures, which explains the seeming peculiarity that linear heating at lower temperatures can lead to stronger clustering than isothermal ageing at a higher *** trends are well simulated using a recently developed precipitation model. New aspects about the evolution of these clusters at higher temperatures are revealed by correlating the different measured properties. The methodology applied here could also be extended to investigating more complex nonisothermal heat treatments.

关键词： Al alloys Al-Mg-Si Non-isothermal ageing Linear heating Precipitation hardening Solute clustering Vacancies

Application of the buffer theory for evaluating attenuation and natural remediation of ionic pollutants in aquatic ecosystems

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

Ecological Processes 2015年第1期4卷 180-189页

作者： igor Povar Oxana Spinu institute of Chemistry of Academy of Sciences of Moldova 3 Academiei str.ChişinăuMD 2028Republic of Moldova

The main focus in this review is showing how to use the developed buffer theory for assessing and predicting the long-term phenomena of attenuation and natural remediation of ionic pollutants in contaminated aquatic ecosystems,as well as for analyzing the way by which metals move and transform within the environment,the distribution of metals in ecosystems,their deposition and cycling in the terrestrial *** buffer theory is based on the rigorous thermodynamic analysis of complex chemical equilibria under environmental conditions in aquatic ecosystems,as natural waters and *** has been established that both homogeneous and heterogeneous systems manifest a buffer action towards all their *** buffer properties in relation to the solid phase components are amplified with an increase of solubility due to protolytic or complex formation equilibria in saturated *** has been established that the buffer capacities of components are mutually proportional,whereas for heterogeneous systems these relationships depend on the stoichiometric composition of solid *** use of the developed buffer approach may yield extended knowledge and a deeper understanding of the processes that control the concentrations of components.A number of the important conclusions concerning the investigated buffer systems have been *** obtained results are indented to provide researchers with a tool needed to help them to set reliable limits of ion(metal)levels in the environment.

关键词： Buffer capacity Ecosystem Heterogeneous multicomponent system Proportionality relation between buffer capacities

Chaotic Simulator for Bilevel Optimization of Virtual Machine Placements in Cloud Computing

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 the Operations Research Society of China 2022年第4期10卷 703-723页

作者： Timothy Ganesan Pandian Vasant igor Litvinchev Member of American Mathematical Society AlbertaT2P 0X2Canada Universiti Teknologi Petronas Seri Iskandar32610Malaysia Nuevo Leon State University San Nicolás de los GarzaNuevo LeónCP66450Mexico

The drastic increase in engineering system complexity has spurred the development of highly efficient optimization *** real-world optimization problems have been identified as bilevel/multilevel as well as *** primary aim of this work is to present a framework to tackle the bilevel virtual machine(VM)placement problem in cloud *** is done using the coupled map lattice(CML)approach in conjunction with the Stackelberg game theory and weighted-sum *** VM placement problem was modified from the original multiobjective(MO)problem to an MO bilevel formulation to make it more realistic albeit more *** comparative analysis on the performance of the CML approach was carried out against the particle swarm optimization method.A new bilevel metric called the cascaded hypervolume indicator is introduced and applied to measure the dominance of the solutions produced by both *** analysis on the computational results is presented.

关键词： Bilevel multiobjective Coupled map lattices(CML) Stackelberg game theory Particle swarm optimization(PSO) Cascaded hypervolume indicator(cHVi) Virtual machine(VM)placement

A New Convergent Explicit Tree-Grid Method for HJB Equations in One Space Dimension

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2018年第1期11卷 1-29页

作者： igor Kossaczky Matthias Ehrhardt Michael Gunther Lehrstuhl fur Angewandte Mathematik und Numerische Analysis Fakultat fur Mathematik und NaturwissenschaftenBergische Universitat WuppertalGaußstrasse 2042119 WuppertalGermany

in this work we introduce a new unconditionally convergent explicit Tree-Grid Method for solving stochastic control problems with one space and one time dimension or equivalently,the corresponding Hamilton-Jacobi-Bellman *** prove the convergence of the method and outline the relationships to other numerical *** case of vanishing diffusion is treated by introducing an artificial diffusion *** illustrate the superiority of our method to the standardly used implicit finite difference method on two numerical examples from finance.

关键词： Tree-Grid Method Hamilton-Jacobi-Bellman equation Stochastic control problem

Mud volcano origin of the Mottled Zone,South Levant

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2013年第5期4卷 597-619页

作者： igor Novikov Yevgeny Vapnik inna Safonova institute of Geology and Mineralogy SB RAS Koptuyga Ave.3Novosibirsk 630090Russia Department of Geological and Environmental Sciences Ben-Gurion University of the NegevP.O.B.653Beer-Sheva 84105Israel

The Mottled Zone（MZ） or Hatrurim Formation,which occurs near the Levantine Transform in the South Levant,has been studied during the last 150 years but its origin remains *** Zone Complex/Complexes（MZC/MZCs） consist of brecciated carbonate and low-temperature calcium-hydro-silicate rocks,which include unusual high- and ultra-high-temperature low-pressure（HT-LP） meta-morphic mineral *** MZ has been regarded as a product of combustion of bituminous chalks of the Ghareb *** Cretaceous（Maastrichtian） *** this paper we present detailed geographic, geomorphologic,structural and geological data from the MZCs of the South Levant,which show that the MZCs cannot be stratigraphically correlated with the Ghareb Fm.,because MZC late Oligocene-late Pleistocene deposits occur within or unconformable i.e.,with stratigraphic hiatus,overlap both the late Cretaceous and,in places,Neogene stratigraphic *** propose an alternative model for the formation of MZCs by tectonically induced mud volcanism during late Oligocene-late Pleistocene time. This model explains（i） the presence of dikes and tube-like bodies,which consist of brecciated exotic clastic material derived from stratigraphically and hypsometrically lower horizons;（ii） mineral assemblages of sanidinite facies metamorphism;（iii） multi-stage character of HT-LP pyrometamorphism;and （iv） multi-stage low-temperature hydrothermal *** temperatures（up to 1500℃） mineral assemblages resulted from combustion of hydrocarbon gases of mud *** volcanism was spatially and structurally related to neotectonic folds and deformation zones formed in response to opening of the Red Sea rift and propagation of the Levantine Transform *** model may significantly change the prospects for oil-and-gas deposits in the region.

关键词： HT-LP sanidinite facies metamorphism Geomorphology Dead Sea Levantine Transform Neotectonics Hydrocarbon traps