T. H. Hanley, H. T. D. Grigg, B. J. Gallacher
Newcastle University, Newcastle-Upon-Tyne, UK
Introducing a disorder into a finite periodic oscillatory system induces the presence of a 'trapped mode': a mode in which the displacement field is localised to the region of the disorder. A main inhibitor to MEMS resonators achieving a high quality (Q) factor is energy radiation through the support to the substrate. The trapped modes present a way to tune this to a minimal value. An initial ...
G. Maizza and M. Longhin
Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Torino, Italy
The excessive presence of residual SiC matrix inter-fiber pores is often the main cause for the very poor mechanical strength and toughness of SiC/SiC composites manufactured by CVI (Chemical Vapour Infiltration) process. This work presents a micro/macro Microwaveassisted Chemical Vapour Infiltration (MW-CVI) model as a strategy to attack the problems above. The proposed model couples a ...
Ramirez, J.C.1, Conlisk, A.T.2
1 Los Alamos National Laboratory, Materials Science and Technology Division
2 The Ohio State University
We present a model for electro-osmotic flow and apply it to examine the effect of complicated geometries on the flow behavior along micro and nano-channels connecting two reservoirs. We perform two and three dimensional simulations. The model consists of the Navier-Stokes equation for the fluid momentum and pressure, species conservation equations for the concentrations of multiple ionic species ...
High Coupling Factor Piezoelectric Materials for Bending Actuators: Analytical and Finite Elements Modeling Results
I.A. Ivan, M. Rakotondrabe, and N. Chaillet
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 ...
Pryor Knowledge Systems, Inc. (COMSOL Certified Consultant), Bloomfield Hills, Michigan, USA
Materials and their related properties are intrinsically fundamental to the creation, development and solution of viable exploratory models when using numerical analysis software. In many cases, simply determining the location, availability and relative accuracy of the necessary material parameters for the physical behavior of even commonly employed design materials can be very difficult and time ...
H. Sun, and F. Jamil
University of Massachusetts, Lowell
The micromixer is one of the important components of Lab-On-a-Chip, but where the molecular diffusion, which is often a slow process, limits the mixing efficiency of two or more streams due to the unique laminar flows in these micro scale devices. This paper studies a mixing concept based on a vibrating micro-plate in the microfluidic channels to achieve an efficient mixing ability. A ...
G. Soni, C. Meinhart, and T. Squires
University of California Santa Barbara
Induced Charge Electroosmosis (ICEO) refers to a fluid flow phenomenon in which an electric field induces a charge cloud (electric double layer) on a polarizable surface and sets up a tangential electric field to move this charge cloud along the surface, which in turn causes a fluid flow pattern. In our case, we considered nonlinear effects such as nonlinear capacitance, surface conduction, ...
A. Cantu-Perez, S. Ping Kee, and A. Gavriilidis
University College London, Department of Chemical Engineering, Torrington Place, London, UK
The mixing characteristics and residence time distributions (RTDs) of a staggered herringbone microchannel have been investigated numerically by COMSOL Multiphysics and by particle tracking algorithms that incorporate diffusion via a random walk. All simulations were validated with experimental data. It was found that for low Peclet numbers the use of herringbone structures have little impact on ...
A. Auge, A. Weddemann, F. Wittbracht, B. Vogel, and A. Hütten
Department of Physics, Thin Films and Physics of Nanostructures, Bielefeld University, Bielefeld, Germany
The oxidation behavior of metallic nanoparticles is investigated in respect to material parameters like Mott potential, defects on the microstructure and oxide volume increase per ionic defect. An emphasis is laid on magnetic nanoparticles where the degree of oxidation can be measured via the reduction of the magnetic moment.
Experimentally Matched Finite Element Modeling of Thermally Actuated SOI MEMS Micro-Grippers Using COMSOL Multiphysics
M. Guvench, and J. Crosby
University of Southern Maine, Gorham, Maine, USA
In “Micro-Electro-Mechanical-Systems” shortly known as MEMS, one of the most important and effective principle of creating transduction of electrical power to displacement force is thermal expansion. A slim beam of MEMS material, typically Silicon, is heated by the application of electrical current via Joule heating; it expands and creates motion. In the design of many MEMS devices ...