Technical Papers and Presentations

Ici vous trouverez les présentations issues des Conférences COMSOL à travers le monde. Réalisées par des utilisateurs de COMSOL Multiphysics, ces présentations explorent tous les domaines actuels d'innovation. Les applications couvrent pratiquement tous les secteurs industriels et impliquent des phénomènes électriques, mécaniques, fluidiques et chimiques. Utilisez la recherche rapide pour trouver les présentations les plus intéressantes dans votre domaine d'intérêt.

A Study of Curved Flexures for MEMS

Minhee Jun[1], and Jason V. Clark[1]
[1]Departments of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA

Large deflection actuators are becoming increasingly important for microsystems. Since actuation forces are usually small, large deflection actuators usually require flexures with low stiffness. Rectangular serpentine flexures are often used for such actuators due to their low stiffness and large linear deflection range. In this paper we investigate the performance of curved serpentine flexures ...

High Coupling Factor Piezoelectric Materials for Bending Actuators: Analytical and Finite Elements Modeling Results

I.A. Ivan[1], M. Rakotondrabe[1], and N. Chaillet[1]
[1]FEMTO-ST Institute, University of Franche-Comte, Besançon, France

New giant piezoelectric factor materials such as PMN-PT and PZN-PT were researched during the last decade and are actually becoming commercially available. As they seem very attractive for actuator designs, we studied their potential in replacing PZT ceramics. In a first comparative approach, we tested a series of classic rectangular composite bimorph structures of different combinations of ...

Chaotic Behavior of the Airflow in a Ventilated Room

A.W.M. van Schijndel[1]
[1]Eindhoven University of Technology, Eindhoven, The Netherlands

Chaotic systems may lead to instability, extreme sensitivity and performance reduction. Therefore it is unwanted in many cases. Due to these undesirable characteristics of chaos in practical systems, it is important to recognize such a chaotic behavior. The existence of chaos has been discovered in several areas during the last 30 years. However, there is a lack of studies in relation with ...

Including Expert Knowledge in Finite Element Models by Means of Fuzzy Based Parameter Estimation

O. Krol[1], N. Weiss[1], F. Sawo[1], and T. Bernard[1]

[1]Fraunhofer Institute for Information and Data Processing, Karlsruhe, Germany

In this paper we present a novel approach for modeling spatial distributed bio- chemical and environmental processes like the growth of plants and the related biochemical reactions. The physical phenomena like flow and mass transport can be described by fluid dynamics equations, but for effects like growth rates often no analytic models are available. However, in many cases experts have knowledge ...

COMSOL Multiphysics® as a Tool to Increase Safety in the Handling of Acetylene Cylinders Involved in Fires

F. Ferrero[1], M. Beckmann-Kluge[1], and K. Holtappels[1]

[1]BAM Federal Institute for Materials Research and Testing Division II.1 “Gases, Gas Plants”, Berlin, Germany

In this paper a mathematical model for predicting the heating-up of an acetylene cylinder involved in a fire is presented. In the simulations polynomial functions were used to describe the temperature dependency of the thermal properties of the cylinder interior, which is a complex system composed by a solid porous material, a solvent and acetylene dissolved in it. Model equations covered heat ...

Reactor Design Improvements for a Propane Autothermal Reformer by Simulation of Momentum Flow

F. Cipitì, L. Pino, A. Vita, M. Laganà, and V. Recupero
CNR-ITAE, Messina

The paper presents a two-dimensional model to describe the gas flow in a propane autothermal reactor, developed at the CNR-ITAE Institute, and aimed to design a Beta 5 kWe hydrogen generator, named HYGen II, to be used with Polymer Electrolyte Fuel Cells (PEFCs) for residential applications. The main aim of the mathematical model was to optimize the reactor geometrical key parameters (diameter ...

An Agglomerate Model for the Rationalisation of MCFC Cathode Degradation

B. Bozzini[1], S. Maci[1], I. Sgura[2], R. Lo Presti[3], and E. Simonetti[3]
[1]Dipartimento di Ingegneria dell’Innovazione, Università del Salento, Lecce, Italy
[2]Dipartimento di Matematica, Università del Salento, Lecce, Italy
[3]ENEA Casaccia, Dipartimento TER, Centro Ricerche Casaccia, S. Maria di Galeria, Roma, Italy

This paper describes the numerical modeling of a key material-stability issue within the realm of Molten Carbonate Fuel Cells (MCFC). The model describes the morphological and attending electrocatalytic evolution of porous NiO electrodes and is apt to predict electrochemical observables that can be recorded during Fuel Cell operation. The model has been validated with original experimental data ...

Optimization of a Thermal Actuator for Low Power/Low Cost Applications

R. Zúñiga-Quesada[1], M. Vílchez-Monge[1], P. Vega-Castillo[1]
[1]Instituto Tecnológico de Costa Rica, Cartago, Costa Rica

This work describes the study of a thermal actuator and modifications to the materials employed in order to decrease power consumption and implementation costs. For this study, we worked on improving the thermal actuator described in the work of T. Ebefors. The criteria for choosing the new materials were lower power consumption, commercial availability, and ease processing. The thermal actuator ...

Kinetics and Plasma Modeling of Plasma Steam Reforming at Atmospheric Pressure

J.M. Cormier, F. Ouni, and A. Khacef
GREMI, Polytech’Orléans

Gliding discharges at atmospheric pressure were investigated in the GREMI laboratory for different applications such as syngas production from methane steam reforming. In our case, the kinetics could be described by using a simplified second order model in which the rate reaction coefficient is obtained from a linearization of parameters. Calculated and experimental data are presented ...

Spatial Model of Glycolysis in Neutrophils

T.A. Hansen, and L.F. Olsen
Department of Biochemistry and Molecular Biology, University of Southern Denmark

In an attempt to understand the mechanism and function of NAD(P)H waves in neutrophils, we have constructed a spatial model of glycolysis in neutrophils. The model does give rise to traveling NADH waves, but there are significant differences between the experimentally observed waves and the waves generated by the model. Based on the model we therefore conclude that it is doubtful that the ...

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