Aqui você encontrará apresentações realizadas nas Conferências de Usuários COMSOL de todo o mundo. As apresentações englobam pesquisas e produtos inovadores feitas por engenheiros e cientistas usando o COMSOL Multiphysics. Os tópicos abramgem uma grande gama de indústrias e aplicações, como elétrica, mecânica, escoamento e química. Use a função de busca "Quick Search" para encontrar apresentações na sua área de interesse.

Numerically Closing the Loop of the Adaptive Optics Sensor: the Validation of the COMSOL Multiphysics® Simulation - new

C. Del Vecchio[1], R. Briguglio[1], A. Riccardi[1]
[1]National Institute for Astrophysics, Arcetri Astrophysical Observatory, Florence, Italy

As any other modelling of a physical behavior, the numerical simulation of the mechanical response of an adaptive secondary mirror requires that the results match the experimental data. Such an agreement was recently demonstrated for the local mirror stiffness of the LBT and VLT Deformable Mirrors; a reliable modeling is a good tool for the extrapolation of the missing optical data (spider ...

Simulations of Micropumps Based on Tilted Flexible Structures - new

M. J. Hancock[1], N. H. Elabbasi[1], M. C. Demirel[2]
[1]Veryst Engineering, LLC, Needham, MA, USA
[2]The Pennsylvania State University, University Park, PA, USA

Pumping liquids at small scales is challenging because of the principle of reversibility: in a viscous regime, the flow streamlines through a fixed geometry are the same regardless of flow direction. Recently we developed a class of microfluidic pump designs based on tilted flexible structures that combines the concepts of cilia (flexible elastic elements) and rectifiers (e.g., Tesla pump). We ...

Variation of the Frost Boundary below Road and Railway Embankments in Permafrost Regions in Response to Solar Irradiation and Winds 

N.I. Kömle[1] and W. Feng[2]
[1]Space Research Institute, Austrian Academy of Sciences, Graz, Austria
[2]State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China

We present COMSOL solutions for a coupled gas flow and heat transfer problem, which occurs particularly when traffic pathways are constructed in high altitude and arctic regions, where the underground is frozen soil. To avoid melting of the frozen ground (which usually leads to mechanical instability) one has to find suitable measures to keep the subsurface soil and the embankment suitably cool. ...

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 ...

Modeling of Nerve Stimulation Thresholds and Their Dependence on Electrical Impedance with COMSOL

P. Krastev[1], and B. Tracey[1]
[1]Neurometrix, Inc., Waltham, Massachusetts, USA

Nerve localization is important for applications in regional anesthesia. Localization is achieved by stimulating the nerve with an electric field produced by a current from a needle inserted into the body of the patient, close to the target nerve.  Modeling of the electric field in close proximity to the nerve may help to explain observed variations in threshold currents and can help to ...

The Effect of a Correlated Surface Roughness and Convection on Heat Conduction

A.F. Emery[1]
[1]Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA

Heat conduction through a slab, 0 ≤ x ≤ W is one dimensional. However, if one of the edges, say x=0, is rough the conduction will be two dimensional. The two dimensionality varies with the correlation length with a maximum at a length approximately 10% of the slab width. The maximum percentage standard deviation of the flux is of the order of 3 time that of the roughness. Monte ...

Effect of Local Deformation on the Emission Energy of  Quantum Dots in a Flexible Tube

S. Kiravittaya[1], P. Cendula[2], A. Rastelli[2], and O. Schmidt[2]
[1]Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
[2]Institute for Integrative Nanosciences, Dresden, Germany

Strain induced by local deformation of a flexible micrometer-sized semiconductor tube is quantified by modeling a ball pressing on the tube wall. By changing the pressing condition, we are able to change the strain state of the tube wall incorporating self-assembled quantum dots (QDs) in the wall. The QD emission energy is calculated in COMSOL® by solving the Schrödinger wave equation ...

Image Based-Mesh Generation for Realistic Simulation of theTranscranial Current Stimulation

R. Said[1], R. Cotton[1], P. Young[1], A. Datta[2], M. Elwassif[2] , and M. Bikson[2]
[1] Simpleware Ltd, Exeter, Devon, UK
[2] Department of Biomedical Eng., The City College of New York, New York, NY, USA

This paper will discuss the comprehensive solution adopted for converting the 3D digital/medical images directly into the computational model. The workflow using Simpleware Software – ScanIP and + ScanFE – will be illustrated including the option for directly exporting fully compatible models to COMSOL Multiphysics. The extra functionality that allows introduction, positioning and ...

Finite Element Analysis of Muscular Contractions from DC Pulses in the Liver

G. Long, D. Plescia, and P. Shires
Ethicon Endo-Surgery, Cincinnati, OH, USA

Thermal ablation of malignant tumors has been conducted in patients who are not candidates for surgery for more than ten years. Recently it has been shown that low energy DC pulses can cause cell necrosis. An undesirable characteristic of DC pulses in-vivo is the stimulation of skeletal muscle. The intensity of the contraction depends in part on the duration and height of the pulse. Through the ...

Localization of Chemical Sources Using Stochastic Differential Equations in Realistic Environments

A. Mohammed, and A. Jeremic
McMaster University, Hamilton, L8S4K1, Canada

Signal processing algorithms for chemical sensing/monitoring have been subject of considerable research interest in the recent years mainly due to their diverse applicability. When the concentration of chemical agent is small, the dispersion of particles is governed by stochastic differential equations describing more complex motion mechanisms such as Brownian motion. In this paper we propose ...

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