R. Pandya , A. Kumar , V. Runkana ,
 Tata Research Development and Design Centre, Tata Consultancy Services, Pune, India
 Indian Institute of Technology, Delhi, India
Electrospinning is a process where high voltage is applied to produce polymer fibers of nanoscale diameter. Various polymers have been used for this process in molten form or as a solution with an appropriate solvent such as glycerol. The melt solidifies while the solvent evaporates to produce fibers. The fibers produced have properties such as high surface to volume ratio and a molecular ...
A Time Dependent Dielectric Breakdown (TDDB) Model for Field Accelerated Low-K Breakdown Due To Copper Ions
R. Achanta, J. Plawsky, and W. Gill
Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
We have simulated the copper ion concentration and internal electric field profiles in a dielectric material by solving the transient continuity/Poisson equations using COMSOL Multiphysics. We have shown that failure of dielectrics can be modeled if we assume that failure in Cu/SiO2/Si devices occurs due to a pile-up of copper ions at the cathode and the subsequent increase in electric field ...
T. Burnett, and D. Lower
CH2M-WG Idaho, LLC
The Idaho Cleanup Project at the Idaho National Laboratory
Idaho Falls, ID
Hot Isostatic Pressing (HIP) has been selected as a means of treating calcined high level waste (HLW). The process combines high temperature and pressure to densify the HLW in to a mineral similar to the geologic formulation of granite. This study uses COMSOL to predict densification and shape deformation of a stainless steel can filled with HLW. Two approaches were used to model ...
N. H. Elabbasi, M. J. Hancock, S. B. Brown
Veryst Engineering, LLC., Needham, MA, USA
Wear is a complex phenomenon relevant to many problems involving frictional contact, such as mechanical brakes, seals, metal forming, and orthopedic implants. The rate of wear depends on the properties of the contacting materials and operating conditions. One widely used model of wear is Archard’s law, which relates the rate of material removal due to wear to the contact pressure, sliding ...
3D Multiphysics Modeling of Bulk High-Temperature Superconductors for Use as Trapped Field Magnets - new
M. Ainslie, J. Zou, D. Hu, D. Cardwell
Department of Engineering, University of Cambridge, Cambridge, UK
The authors are currently investigating the use of bulk high temperature superconductors as trapped field magnets (TFMs) in order to increase the electrical and magnetic loading of an axial gap, trapped flux-type superconducting electric machine. In electric machines, the use of superconducting materials can lead to increases in efficiency, as well as power density, which results in reductions ...
2D Axial-Symmetric Model For Fluid Flow And Heat Transfer In The Melting And Resolidification Of A Vertical Cylinder
S. Morville, M. Carin, M. Muller, M. Gharbi, P. Peyre, D. Carron, P. Le Masson, and R. Fabro
Laboratoire LIMATB, Université de Bretagne Sud, Lorient , France
Laboratoire PIMM, Arts et Métiers ParisTech, Paris, France
Laser direct deposition is a process, different from molding or machining, which allows the producing of fully densified and operational components. This technique involves injecting metal powder through a coaxial nozzle into a melt pool obtained by a moving laser beam. The final object is obtained by superimposing the layers created by the process. The roughness of the functional part is ...
蒋帆 , 孙衢骎 ,
目前，脉冲磁体广泛采用导体绕组和加固材料分层交替绕制的工艺（内部层间加固），以提高磁体的整体结构强度。磁体在长期的放电工作过程中，反复经历强电磁力的作用，导体材料（一般为纯铜、铜基合金以及铜基复合材料）在重复的加卸载过程中存在着塑性应变的累积效应，即棘轮效应。导体材料塑性应变的逐渐累积，导致了磁体不可逆电感值的不断增加。因此，磁体的不可逆电感变化可表征磁体内部的整体变形情况，可用于脉冲磁体的疲劳失效预测。 本文基于 COMSOL Multiphysics® 5.1 软件，对脉冲磁体的放电过程建立了电路、电磁场、温度场及结构场的二维轴对称全耦合模型。考虑了放电过程中集肤效应对磁体电阻、电感的影响；在结构场中引入了接触对，采用罚函数法对磁体内部的层间分离机制进行了有效的模拟；利用耦合变量，基于 ALE 方法计算了脉冲磁体在服役过程中 ...
A. Traidia, and F. Roger
AREVA NP, Technical Center, Saint Marcel, France
ENSTA Paristech, Paris, France
Using COMSOL Multiphysics, a finite element model is introduced in this paper to describe the couplings between the welding arc and the weld pool dynamic in pulsed gas tungsten arc welding. The cathode, arc-plasma and melting anode regions are taken into account. The unified time-dependent model describes the heat transfer, fluid flow and electromagnetic fields in the three regions. The ...
M. A. Shah , F. Iqbal , B. L. Lee ,
 Korea University of Technology and Education, Cheonan, Chungcheong, South Korea
A dual axis MEMS seismometer targeted for building monitoring system has been simulated for a full scale of ±5g acceleration. The design uses the capacitive effect for vibration sensing. This comb drive capacitive MEMS seismometer consists of 8 springs with two proof masses. The device is very low cross axis sensitive (almost negligible cross axis error). The cross axis sensitivity of x-axis is ...
P. Zilio , W. Raja , A. Alabastri , R. Proietti Zaccaria 
 Istituto Italiano di Tecnologia, Italy
 Istituto Italiano di Tecnologia, Italy
 Rice University, USA
The formation of space charge clouds is a well known problem that affects thermionic emitters in regimes of high current emission. Although some analytical models have been presented, suitable for 1D geometries, the modeling of the problem in complex 3D structures remains a challenge due to the mutual coupling between electron trajectories and field they produce. Here we propose a model able to ...