Artigos Técnicos e Apresentações

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.

Detection of Magnetic Particles by Magnetoresistive Sensors

A. Weddemann[1], A. Auge[1], F. Wittbracht[1], C. Albon[1], and A. Hütten[1]
[1]Department of Physics, Thin Films and Physics of Nanostructures, Bielefeld University, Bielefeld, Germany

In this work, we demonstrate the implementation of the micromagnetic equations for the description of ferromagnetic thin films in COMSOL Multiphysics®. We apply our model to magnetoresistive sensors consisting of several soft ferromagnetic layers and their response to magnetic particles. The magnetization dynamic of the particles needs to be described in a similar manner, though due to size ...

Particle Flow Control by Magnetically Induced Dynamics of Particle Interactions

F. Wittbracht[1], A. Weddemann[1], A. Auge[1], and A. Hütten[1]

[1]Department of Physics, Thin Films and Physics of Nanostructures, Bielefeld University, Bielefeld, Germany

In this work, we show that dipolar magnetic coupling can be used to control the particle flow through microfluidic structures without changing the state of motion of the carrier liquid. Also no external magnetic gradient fields are employed; the total external magnetic force applied is therefore zero. The theoretical idea will be tested experimentally. Here, additional effects originating from ...

A Magnetically Driven Micro-Mixing Device and its Numerical Analysis

A. M. Morega1, J. C. Ordonez2, and M. Morega1
1Politehnica University of Bucharest, Bucharest, Romania
2Florida State University, Tallahassee, FL, USA

In this paper, we present a FEM model of a mixing MEMS μTAS device. A quasistatic magnetic field, produced by sequentially switched DC currents advected through conductors embedded in the device substrate beneath the flow channel, is used to mix the working magnetic fluid, while it is forced to flow through a rib walled channel. The body forces in the magnetized fluid perturb the otherwise ...

Shape, Convection and Convergence

R. Pryor
Pryor Knowledge Systems, Inc., Bloomfield Hills, MI, USA

COMSOL Multiphysics software, when properly configured, can readily solve modeling problems in the laminar flow regime using the standard Navier-Stokes equations or in the fully turbulent flow regime using the kappa-epsilon model. Failure to solve a particular model is typically manifested by instability in the calculation and a failure of the model to converge. This paper presents a new approach ...

Modeling and Characterization of Superconducting MEMS for Microwave Applications in Radioastronomy

N. Al Cheikh[1], P. Xavier[1], J. Duchamp[1], and K. Schuster[2]
[1]Institute of Microelectronics, Electromagnetism and Photonics (IMEP-LAHC), Grenoble, France
[2]Institute of Millimetrics Radio Astronomy (IRAM), Grenoble, France

Superconducting GHz electronics circuits are frequently used in Radio Astronomy instrumentation. The features of these instrumentations can be significantly improved by using tuneable capacitances, which can be realized by electrically actuated, micromechanical bridges (MEMS) made of superconducting Niobium (Nb). In order to analyze the electromechanical behavior of such devices and the intrinsic ...

Multiphysics Modeling of Nanoparticle Detection - Current Status and Collaboration Sought

D. Krizaj[1], I. Iskra[2], Z. Topcagic[1], and M. Remskar[2]
[1]University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
[2]Institut Jozef Stefan, Ljubljana, Slovenia

We are developing nanoparticle detector for airborn particles. The detection principle is based on condensation of nanoparticles forming micron sized water droplets and detection of the droplets by a capacitive type nanodetector. We have successfully performed some experimental evaluations of the detection principle and are in the stage of optimization of several parts of the system. As shown ...

Evaluation of electric impedance spectra for single bio-cells in microfluidic devices using combined FEMLAB/ELDO modeling

Senez, V., Arscott, S.
CNRS/IEMN

This paper describes a simple method to predict the electrical impedance spectrum of single and cultured cells in micro-devices. It can be used for the rapid design of micro-sensors as well as for more fundamental studies about the interactions of electric fields with bio-cells. The finite element (FEMLAB) and the transport lattice (ELDO) methods are coupled through the MATLAB environment for ...

Droplet Generation by Means of a Two-Fluid Probe

B.P. Cahill[1], M. Quade[1], G. Gastrock[1], K. Lemke[1], J. Metze[1], and D. Beckmann[1]

[1]Institut für Bioprozess und Analysenmesstechnik e.V., Rosenhof, Heilbad Heiligenstadt, Germany

This paper presents a simulation of the operation of a new type of droplet generation probe. This probe, consisting of two concentrically-arranged tubings, is immersed in a beaker of cell medium so that oil is pumped through the outer tubing at a pumping speed less than fluid is drawn into the inner tubing. In this way, droplets of cell medium are entrained into the outlet tubing forming a ...

Simulation of Magnetic Beads in on-chip Structures

A. Weddemann, A. Hütten, S. Herth, and M. Schilling
Universität Bielefeld, Fakultät für Physik, Bielefeld

In this work, a system for magnetic and hydrodynamic manipulation of magnetic beads is modelled. A geometry is introduced to assure a good separation behaviour with respect to the magnetic moment of the particles. Different separation mechanisms will be discussed and an estimation of the minimal difference of separable magnetic moments will be given. Further it will be shown, that the ...

COMSOL Multiphysics Modeling of Rotational Resonant MEMS Sensors with Electrothermal Drive

S. Nelson[1], and M. Guvench[1]
[1]University of Southern Maine, Gorham, Maine, USA

COMSOL Multiphysics is employed to model, simulate and predict the performance of a high Q, in-plane rotational resonating MEMS sensor. The resonating sensor disk is driven by thermal expansion and contraction of the support tethers due to AC joule heating. The resonant frequency is sensed by stationary contacts. For cost reduction, the relatively simple, low cost SOIMUMPS fabrication process is ...

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