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101.
This paper outlines the benefits of computational steering for high performance computing applications. Lattice-Boltzmann mesoscale fluid simulations of binary and ternary amphiphilic fluids in two and three dimensions are used to illustrate the substantial improvements which computational steering offers in terms of resource efficiency and time to discover new physics. We discuss details of our current steering implementations and describe their future outlook with the advent of computational grids. 相似文献
102.
Fin materials can be observed in a variety of engineering applications. They are used to ease the dissipation of heat from a heated wall to the surrounding environment. In this work, we consider a nonlinear fin problem with temperature-dependent thermal conductivity and heat transfer coefficient. The equation(s) under study are highly nonlinear. Both the thermal conductivity and the heat transfer coefficient are given as arbitrary functions of temperature. Firstly, we consider the Lie group analysis for different cases of thermal conductivity and the heat transfer coefficients. These classifications are obtained from the Lie group analysis. Then, the first integrals of the nonlinear straight fin problem are constructed by three methods, namely, Noether’s classical method, partial Noether approach and Ibragimov’s nonlocal conservation method. Some exact analytical solutions are also constructed. The obtained result is also compared with the result obtained by other methods. 相似文献
103.
Jorge Bustamante Abisaí Carrillo-Zentella José M. Quesada 《Acta Mathematica Hungarica》2012,136(1-2):90-106
We present direct and strong converse theorems for a general sequence of positive linear operators satisfying some functional equations. The results can be applied to some extensions of Baskakov and Szász–Mirakyan operators. 相似文献
104.
Manuel Quesada‐Pérez Silvia Ahualli Alberto Martín‐Molina 《Journal of Polymer Science.Polymer Physics》2014,52(21):1403-1411
In this work, slightly charged thermo‐responsive gels in the presence of salt at concentrations close to physiological conditions have been simulated within a coarse‐grained model widely used in the last decade. These simulations allow differentiate charge and salt effects, which are antagonist and coupled in many real systems because the degree of ionization might depend on the electrolyte concentration. An analysis in terms of the different contributions to osmotic pressure is also presented, which highlights the role played by excluded volume effects. In addition, our results also permit us to test some predictions based on the ideal Donnan equilibrium, a common assumption made to justify the swelling behavior of gels and microgels in the presence of salt. More specifically, simulations show that, for the slightly charged gels simulated here, such an assumption overestimates the concentration of salt inside collapsed gels and underestimates the excess of osmotic pressure associated to the additional electrolyte. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1403–1411 相似文献
105.
106.
Ernesto Quesada 《Tetrahedron letters》2005,46(38):6473-6476
The direct conversion of activated primary alcohols into terminal alkynes through a sequential one-pot, two-step process involving oxidation with manganese dioxide and then treatment with the Bestmann-Ohira reagent is described. This transformation proceeds efficiently (59-99% yield) under mild reaction conditions with a range of benzylic, heterocyclic and propargylic alcohols. A tandem variant is also described, which is successful only with highly activated substrates. 相似文献
107.
Debbie Cannon Christopher Glidewell John N. Low Antonio Quesada James L. Wardell 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(2):216-221
4-Methyl-2-nitroaniline, (I), C7H8N2O2, crystallizes with two molecules in the asymmetric unit. The molecules both form intramolecular N—H⃛O hydrogen bonds and they are linked into hydrogen-bonded C22(12) chains in which the two independent molecules alternate. 4,5-Dimethyl-2-nitroaniline, (II), C8H10N2O2, also has Z′ = 2 and the two independent molecules each form hydrogen-bonded C(6) chains. In 4-methyl-3-nitroaniline, (III), C7H8N2O2, there are four molecules in the asymmetric unit. Molecules of two of these types are linked by N—H⃛O hydrogen bonds into molecular ladders containing R43(18) rings and the other two types independently form single C(7) chains. 相似文献
108.
F. Rubio-Marcos A. Quesada M.A. García M.A. Bañares M.S. Martín-Gonzalez J.F. Fernández 《Journal of solid state chemistry》2009,182(5):1211-44
Raman spectroscopy is used to evidence both the nature of the interphase reaction between ZnO and MnO2 particles and its kinetic evolution. Zn cations migrate from the ZnO grains during oxygen vacancies formation process and diffuse into the MnO2 particles leading to an interphase region with an intermediate valence Mn+3-O-Mn+4. Large amounts of desorbed Zn cations promote the formation of ZnMn2O4 structure, in addition to the intermediate valence state. The system evolves towards complete formation of the spinel phase at higher thermal treatment times. The reactivity of the ZnO plays an important role in the formation of this interphase. Low-reactivity ZnO powder, in which the oxygen vacancies are previously produced, shows a stabilization of the intermediate valence state with very limited formation of the spinel phase. A clear correlation between the amount of the intermediate state interphase and the magnetic properties has been established. 相似文献
109.
110.
Alejandro Arbelaez Deepak Mehta Barry O’Sullivan Luis Quesada 《Journal of Heuristics》2018,24(3):359-394
Many network design problems arising in areas as diverse as VLSI circuit design, QoS routing, traffic engineering, and computational sustainability require clients to be connected to a facility under path-length constraints and budget limits. These problems can be seen as instances of the rooted distance-constrained minimum spanning-tree problem (RDCMST), which is NP-hard. An inherent feature of these networks is that they are vulnerable to a failure. Therefore, it is often important to ensure that all clients are connected to two or more facilities via edge-disjoint paths. We call this problem the edge-disjoint RDCMST (ERDCMST). Previous work on the RDCMST has focused on dedicated algorithms and therefore it is difficult to use these algorithms to tackle the ERDCMST. We present a constraint-based parallel local search algorithm for solving the ERDCMST. Traditional ways of extending a sequential algorithm to run in parallel perform either portfolio-based search in parallel or parallel neighbourhood search. Instead, we exploit the semantics of the constraints of the problem to perform multiple moves in parallel by ensuring that they are mutually independent. The ideas presented in this paper are general and can be adapted to other problems as well. The effectiveness of our approach is demonstrated by experimenting with a set of problem instances taken from real-world passive optical network deployments in Ireland, Italy, and the UK. Our results show that performing moves in parallel can significantly reduce the elapsed time and improve the quality of the solutions of our local search approach. 相似文献