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Mesoscopic model for binary fluids

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Frontiers of physics 2017年第5期12卷 231-239页

作者： C. Echeverria K. Tucci O. Alvarez-Llamoza E. E. Orozco-Guillén5 M. Morales M. G. Cosenza CeSiMo Universidad de Los Andes Mérida 5251 Mérida Venezuela Grupo de Caos y Sistemas Complejos Centro de Fisica Fundamental Universidad de Los Andes Mérida Venezuela Departamento de Fisica FACYT Universidad de Carabobo Valencia Venezuela Facultad de ingenierla Universidad Católica de Cuenca Ecuador programa Académico de ingenierla en Energla Universidad Politécnica de Sinaloa 82199 Mazatldn Mexico Programa Académico de ingenierla en Nanoteenologla Universidad Politécnica de Sinaloa 82199 Mazatldn Mexico

We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.

关键词： multiparticle collision dynamics mesoscopic models phase separation interface dynamics

IMPROVING SOLVER PERFORMANCE THROUGH REDUNDANCY

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Journal of Systems Science and Systems Engineering 2016年第3期25卷 303-325页

作者： Eduardo Lalla-Ruiz Stefan Voβ Department of Computer Engineering and Systems University of La Laguna Spain Institute of Information Systems (IWI) University of Hamburg Germany Eseuela de ingenierla Industrial Pontificia Universidad Catolica de Valparaiso (PUCV) Chile

It is well known that hierarchies of mathematical programming formulatlons with different numbers of variables and constraints have a considerable impact regarding the quality of solutions obtained once these formulations are fed to a commercial solver. In addition, even if dimensions are kept the same, changes in formulations may largely influence solvability and quality of results. This becomes evident especially if redundant constraints are used. We propose a related framework for information collection based on these constraints. We exemplify by means of a well-known combinatorial optimization problem from the knapsack problem family, i.e., the multidimensional multiple-choice knapsack problem （MMKP）. This incorporates a relationship of the MMKP to some generalized set partitioning problems. Moreover, we investigate an application in maritime shipping and logistics by means of the dynamic berth allocation problem （DBAP）, where optimal solutions are reached from the root node within the solver.

关键词： Erraticism redundant constraints multidimensional multiple-choice knapsack problem,dynamic berth allocation problem

Inference for a truncated positive normal distribution

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Applied Mathematics(A Journal of Chinese Universities) 2018年第2期33卷 163-176页

作者： Hector J.Gomez Neveka M.Olmos Hector Varela Heleno Bolfarine Departamento de Ciencias Matematicas y Ffsicas Facultad de IngenierlaUniversidad Catolica de TemucoTemucoChile Departamento de Matematicas Facultad de Ciencias BasicasUniversidad de AntofagastaAntofagastaChile Departamento de Estatfstica IMEUniversidade de Sao PauloSao PauloBrazil

The main object of this paper is to study an extension of the half normal distribution defined by adding a positive truncation to it. The new model is more flexible than the half-normal distribution and contains the half normal distribution as a special case. Properties of this distribution, such as moments, hazard function and entropy are studied and parameters estimation is dealt with by using inoinents and inaxiinuin likelihood. A real data application indicates good fit performance of the new model when compared to other competitors in litera- tures.

关键词： half-normal distribution maximum likelihood truncation

On the existence of traveling wave solutions and upper and lower bounds for some Fisher-iolmogorov type equations

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International Journal of Biomathematics 2014年第5期7卷 51-65页

作者： Juan Belmonte-Beitia Departamento de Matemdticas E. T. S. de Ingenieros Industriales and Instituto de Matemdtica Aplicada a la Ciencia y la Ingenierla (IMA CI) Universidad de Castilla-La Mancha 13071 Ciudad Real Spain

In this paper, we use a dynamical systems approach to prove the existence of traveling waves solutions for the Fisher-Kolmogorov density-dependent equation. Moreover, we prove the existence of upper and lower bounds for these traveling wave solutions found previously. Finally, we present a particular example which has several applications in the mathematical biology field.

关键词： Fisher-Kolmogorov equations nonlinear diffusion heteroclinic orbits upperand lower solutions center manifold.

SYNCHRONOUS COMMUNICATION IN PLM ENVIRONMENTS USING ANNOTATED CAD MODELS

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Journal of Systems Science and Systems Engineering 2016年第2期25卷 142-158页

作者： Jorge D. Camba Manuel Contero Gustavo Salvador-Herranz Raquel Plumed College of Architecture University of Houston Houston TX USA I3BH Universitat Politkenica de Valkncia Valencia Spain Depto. de Expresion Grafica Proyectos y Urbanismo Universidad CEU Cardenal Herrera Valencia Spain Depto. de ingenierla Mecanica y Construccian Universitat Jaume I Castellon Spain

The connection of resources, data, and knowledge through communication technology plays a vital role in current collaborative design methodologies and Product Lifecycle Management （PLM） systems, as these elements act as channels for information and meaning. Despite significant advances in the area of PLM, most communication tools are used as separate services that are disconnected from existing development environments. Consequently, during a communication session, the specific elements being discussed are usually not linked to the context of the discussion, which may result in important information getting lost or becoming difficult to access. In this paper, we present a method to add synchronous communication functionality to a PLM system based on annotated information embedded in the CAD model. This approach provides users a communication channel that is built directly into the CAD interface and is valuable when individuals need to be contacted regarding the annotated aspects of a CAD model. We present the architecture of a new system and its integration with existing PLM systems, and describe the implementation details of an annotation-based video conferencing module for a commercial CAD application.

关键词： Collaborative design PLM design communication CAD integration videoconferencing

Optimizing the delivery of combination therapy for tumors： A mathematical model

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International Journal of Biomathematics 2017年第3期10卷 179-194页

作者： Clara Rojas Rodriguez Juan Belmonte-Beitia Departamento de Matematicas E. T. S. de Ingenieros Industriales Universidad de CastiUa-La Mancha 13071 Ciudad Real Spain Instituto de Matemdtica Aplicada a la Ciencia y la ingenierla (IMA CI) Universidad de Castilla-La Mancha 13071 Ciudad Real Spain

We present in this paper a new mathematical model for the scheduling of angiogenic inhibitors in combination with a chemotherapeutic agent for a tumor. Our model takes into account the process of angiogenesis and the quality of the vasculature discriminating between stable blood vessels and unstable blood vessels. We characterize theoretically the optimal controls on drug distribution to minimize the number of cancer cells at the end of the treatment in a free horizon time problem with restrictions on the total amount of drug doses. Finally, we solve the optimal control problem by using numerical simulations, obtaining as a result that, despite the number of the tumor cells decrease with anti-angiogenic treatment, the best results are reached at the end of the chemotherapy treatment.

关键词： Mathematical modeling of tumor growth anti-angiogenic treatment chemotherapy singular control bang bang control.

Dynamics of populations with two sexes

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International Journal of Biomathematics 2015年第4期8卷 127-144页

作者： M. Cecilia Perez E. Adriana Saavedra Mariano A. Ferrari Facultad de Ingenieria Universidad Nacional de la Patagonia San Juan Bosco Esquel Chubut Argentina Facultad de Ingenieria Universidad Nacional de la Patagonia San Juan Bosco Trelew Chubut Argentina Facultad de ingenierla Universidad Nacional de la Patagonia San Juan Bosco Puerto Madryn Chubut Argentina Centro Nacional Patagdnico CONICET Puerto Madryn Chubut Argentina

A mathematical model is presented in order to describe the dynamics of polygamous populations, bearing in mind single individuals of both sexes and the development of reproductive groups. In this context, the description leads us to consider positive homogeneous dynamical systems, establishing conditions for the stationary state existence and its local stability. A fourth pre-reproductive stage was considered, i.e. males and females spend part of their lives before being in condition to reproduce, as a first step to consider more general models. Finally, we parametrized the proposed model using southern elephant seal data, to analyze the direct applicability to a real population.

关键词： Dynamical systems two-sex model mating system local stability.

Microcellular Agave Fibre-High Density Polyethylene Composites Produced by Injection Molding

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材料科学与工程（中英文A版） 2012年第11期2卷 677-692页

作者： Cedric Tissandier Roberto Carlos Vazquez Fletes Ruben Gonzalez-Nunez Denis Rodrigue Departement de Genie Chimique Universite Laval Quebec G1 V OA6 Canada Departamento de ingenierla Quimica Universidad de Guadalajara Guadalajara 44430 Mexico

Flotation of Brazilian and Colombian Coals Using a Negative Bias

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Journal of Chemistry and Chemical Engineering 2013年第2期7卷 170-174页

作者： Irineu Brum H. Villegas W. Banguero J. Guerrero C. Sampaio J. Barraza Laboratorio de Processamento Mineral Centro de Tecnologia Universidad Federal Rio Grande do Sul Porto Alegre Brasil Escuela de ingenierla Quimica Universidad del Valle Cali 25360 Colombia

Brazil and Colombia have large reserves of coal. Those reserves in Brazil are located predominantly in the south and the main reserves in Colombia are located in the north. Despite the relative ease of exploitation, these resources have been underestimated as a source of energy. Currently, these countries are developing projects and partnerships aiming to qualify this mineral resource, adding quality to the final product of the processing plants. In this scenario, the processing of Brazilian and Colombian coal in flotation columns appears as a promising alternative, having been successful in mineral systems containing fine particles. The paper aims to study the overall process of column flotation for a specific Brazilian coal and a specific Colombian coal. The material used in this study consists of fine coal from Brazil （Copelmi） and Colombia （Cerrejon）. The objective is to recover carbonaceous matter and reduce the ash and contaminants grade. The two coals were floated using a negative bias in a 5 cm diameter conventional flotation column of 5 m high. Flotation parameter investigated included air velocity in the range 0.6 to 1.5 cm/s. For all runs, a constant negative bias of-0.25 cm/s and a pulp concentration of 8% w/w were used. For Cerrej6n coal, 300 g/ton of frother and 907 g/ton of collector was used, whereas for Copelmi coal, 600 g/ton of frother and 1,815 g/ton of collector was employed. The frother was a commercial Aerofroth 65 （AF65）, whereas the collector was Kerosene. For the Colombian coal, in general, yield, organic recovery, ash recovery and water recovery decreased with the increasing air rate. However, for Brazilian coal the air rate had no significant effect. For Colombian coal, the highest yield （60% w/w） and organic recovery （69% w/w） were obtained at the lowest air rate （0.6 cm/s）.

关键词： Negative bias column flotation coal.