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.

Multiphysics Modeling of Cellular Arrays Using Periodic Minimal Surfaces – A Drug and Gene Delivery Application

J.I. Rey, A.J. Llewellyn, R.J. Connolly, J.P. Jimenez, A.M. Hoff, and R.A. Gilbert
University of South Florida, Tampa, FL, USA

Minimal surfaces are found in nature from crystalline structures to biological nano and micro structures such as biomembranes, and osseous formations in sea urchin. An application to electrically mediated drug and gene delivery is presented. Periodic level surfaces which approximate minimal surfaces are used to generate a geometric representation of tissue. A method to create such structures ...

Modeling of Retinal Electrical Stimulation Using a Micro Electrode Array Coupled with the Gouy-Chapman Electrical Double Layer Model to Investigate Stimulation Efficiency

F. Dupont, R. Scapolan, C. Condemine, J.F. Bêche, M. Belleville, and P. Pham
CEA, LETI, Minatec, Grenoble, France

The electrical stimulation for retinal implant has known significant improvements in the last decades with many implantations and experimentations. The ability to create better controlled and adapted signals to increase the efficiency in stimulation is a major objective. The aim of this study is to develop a numerical platform based on COMSOL Multiphysics to simulate different waveforms. The ...

Multiphysics Model of the NovaSure Endometrial Ablation Procedure

G.T. Martin[1], and L. Angelone[2]
[1]Hologic, Inc., Bedford, Massachusetts, USA
[2]Massachusetts General Hospital, Harvard Medical School, Marlborough, Massachusetts, USA

The NovaSure Endometrial Ablation System® is designed to remove the endometrial lining in the uterine cavity of women who suffer from menorrhagia. The NovaSure disposable device consists of a 2-pole, 4 electrode array that is inserted into the uterine cavity and deployed. We have developed a COMSOL Multiphysics model of the NovaSure ablation process. The model utilized COMSOL Multiphysics ...

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 ...

Physical and FEM Simulation of Microprobe Insertion into Brain Tissue

A. Eed Olamat, U. Hofmann, B. Pohl, and N. Nkemasong
University of Lübeck, Institute for Signal Processing, Lübeck, Germany

In order to investigate the implantation of microprobes into brain tissue, we developed a finite-element and a physical model to replace real biological tissue for mechanical testing. Penetrating forces of a tungsten indenter into a layered structure was investigated with different indentation speeds. Numerical and physical model are in good correspondence to each other and reproduce measured ...

Material Characterization Method Development: From Education to Design Optimization

C. Morgan[1], N. Kenkare[1], M. Williams[2], A. Peterson[2], and D. Williams[2]
[1]Alcon Eye Care Division of Novartis R&D, Duluth, GA
[2]Alcon Eye Care Division of Novartis R&D and Georgia Institute of Technology Co-op Program, GA

Introduction of silicone hydrogel contact lens materials provided products of unprecedented capability to deliver oxygen to the eye during wear. One additional material characteristic of interest is the material’s permeability to ions. This paper discusses descriptive tools and optimization of an impedance method of characterizing ion permeability. A physical model of conductive paper with ...

Some Clinical and Computational Studies On Haemodynamics In Stenosed Artery

A. Chanda, A.R. Choudhury, G. Ray, K. Dasgupta, and D. Nag
Jadavpur University, Kolkata, West Bengal, India

Atherosclerosis in arteries is caused by the formation of stenosis : fatty depositions, on the artery wall. In current medicine, the practice is to observe the maximum percentage occlusion at any arbitrary cross-section and diagnose the patient on that basis, which might not always present the real picture due to non-uniformity of the stenosis thickness. The present work attempts to simulate the ...

Modeling Bacterial Transport and Removal in a Constructed Wetland System

E. Engström, B. Balfors, and R. Thunvik
Royal Institute of Technology, Stockholm, Sweden

In this study we evaluate transport, retention and subsistence of Escherichia coli (E. coli), a common fecal indicator bacteria, in a model (2x1m) of a constructed wetland. Transport occurs in the unsaturated and saturated zone. Inactivation is accounted for as a kinetic first-order process. Retention is assumed to be dominated by solid-air-water interface straining and is modeled with a kinetic ...

An Assessment of the Suitability of the Body and Adult Head Coils for Transmission during Paediatric Magnetic Resonance Imaging

G.R. Cook[1], M.J. Graves[1], F.J. Robb[2], D.J. Lomas[1]
[1]Department of Radiology, University of Cambridge, Cambridge, United Kingdom
[2]General Electric Healthcare Coils, Aurora, Ohio, USA

MRI offers many advantages over other modalities and its lack of ionizing radiation is important for children, but can be limited by the radio-frequency (RF) coils available. This work calculates Specific Absorption Rate (SAR) and homogeneity of the RF transmit field (B1+) when imaging infants in adult coils. Two birdcage-type coils were loaded by a tissue model and their B1+ homogeneities ...

基于 DTI 纤维追踪和有限元力学模型的脑损伤轴突纤维损伤研究

李娜 [1], 李江红 [2]
[1] 中南大学湘雅三医院,长沙,湖南,中国
[2] 中车集团南车研究所,株洲,湖南,中国

研究头部损伤机理是对运动撞击中脑损伤进行预测的有效手段。数学模型是分析损伤实验数据、预测人员碰撞损伤程度的唯一方法,但现有的头部损伤有限元模型基于尸体实验数据,且忽略脑组织结构的各向异性。本项目旨在提出并实现一种以损伤生物力学为基础、结合磁共振扫描 DTI 的轴突走向信息的有限元力学模型。提取脑外伤前的弥散张量成像信息,实现深入到轴突水平有限元力学模型的建立,在有限元模拟中采用非线性超弹性力学模型,并植入 NSGAII 最优化方法对有限元模型的材料参数进行优化,从而提高模型的稳定性和计算精度;将计算预测结果与损伤后 DTI 的 FA 值所表现的轴突断裂情况进行验证, 探索活体环境下碰撞损伤中脑轴突的损伤性变化,从而获得脑外伤损伤程度与力学因素之间的关系,为脑外伤损伤程度的预测和脑外伤损伤标准的校正提供精确完整的信息。本项目的研究成果将在汽车碰撞的乘员防护设计上有重要的理论指导价值。 ...