B. Baumann, J. Schwieger, M. Wolff, F. Manders, J. Suijker
Hamburg University of Applied Sciences, Hamburg, Germany
Philips Lighting, Turnhout, Belgium
High-intensity discharge lamps will in the foreseeable future be important light sources despite a growing market share of LEDs. Cost and energy efficient high frequency (300 kHz) operation is hampered by the excitation of acoustic resonances inside the arc tube, which results in low frequency (10 Hz) light flicker. Our aim is to calculate the acoustic streaming velocity field, which is related ...
S. Gorelick, M. Leivo, U. Kantojärvi
VTT Technical Research Centre of Finland, Espoo, Finland
Excessive air damping can be detrimental to the performance of oscillating MEMS components. Complex systems, such as structures in pre-etched cavities or angular comb-drive scanning mirrors, typically require simulations to reliably evaluate the air damping. The simulated and experimental performance of the following systems was evaluated and compared: two types of out-of-plane cantilevers, ...
J. Crompton, S. Yushanov, L. Gritter, and K. Koppenhoefer
AltaSim Technologies, LLC.
Thermoelectric phenomena provide the direct conversion of heat into electricity or electricity into heat, the phenomena is described by three related mechanisms: the Seebeck, Peltier and Thomson effects. Thermoelectric devices have found many applications ranging from temperature measurement, solid state heating or cooling and direct energy conversion from waste heat. In this paper, analysis ...
A Practical Method to Model Complex Three-Dimensional Geometries with Non-Uniform Material Properties Using Image-based Design and COMSOL Multiphysics®
J. Cepeda, S. Birla, J. Subbiah, H. Thippareddi
Department of Food Science & Technology, University of Nebraska, Lincoln, NE, USA
Department of Biological Systems Engineering, University of Nebraska, Lincoln, NE, USA
Geometries with heterogeneous material properties are typically defined as a set of multiple parts, each part representing a different material. However, assembling or defining the individual parts of complex geometries can be difficult. A practical method based on image-based mesh generation, a custom algorithm for labeling materials, and interpolation functions of COMSOL Multiphysics® can be ...
Z. Zheng, R. Zhang
Corning Incorporated, Corning, NY, USA
Introduction: Glass relaxation occurs in a range of temperature during transition from equilibrium to super-cooled liquid. Viscoelastic material model can be applied to simulate glass behavior during the glass transition regime and to predict the glass deformation and stress evolution. Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when ...
SPAWAR Systems Center (SSC) ATLANTIC, Charleston, SC, USA
Additive manufacturing uses 3D printing to build physical parts from CAD-based designs. The technology includes fused deposition modeling (FDM) and selective laser sintering (SLS) methods. 3-D printing is of particular interest for smaller, one-of-a-kind, customizable products. A cube satellite (CubeSat) containing fiber reinforced SLS parts has been successfully launched (Ref 1). Lower ...
K. M. Al-Shurman, H. Naseem
The Institute for Nanoscience & Engineering, University of Arkansas, Fayetteville, AR, USA
Chemical vapor deposition (CVD) is a promising effective method for synthesis of graphene films. CVD graphene film is obtained from hydrocarbon species such as CH4 through complex catalytic chemical reactions on the surface of the catalyst. Therefore, studying the catalytic reaction kinetics is essential process for understanding the thermal decomposition rate of methane on catalyst surface as ...
L. P. Aoki, H. E. Schulz, M. G. Maunsell
University of São Paulo, São Carlos, SP, Brazil
This article considers a closed water circuit with square cross section filled with an electrolyte fluid. The conductor fluid was moved using an electromagnetic pump, in which a permanent magnet generates a magnetic field and electrodes generate the electric field in the flow. Thus, the movement is a consequence of the magnetohydrodynamic (or MHD) effect. The model adopted here was derived from ...
Diffusion and Reaction in Fe-Based Catalyst for Fischer-Tropsch Synthesis Using Micro Kinetic Rate Expressions - new
A. Nanduri, P. L. Mills
Department of Chemical & Natural Gas Engineering, Texas A&M University, Kingsville, TX, USA
Fischer-Tropsch synthesis (FTS) is a highly exothermic polymerization reaction of syngas (CO+H2) in the presence of Fe/Co/Ru-based catalysts to produce a wide range of paraffins, olefins and oxygenates, often known as syncrude. Multi-Tubular Fixed Bed Reactors (MTFBR) and Slurry Bubble Column Reactors (SBCR) are widely employed for FTS processes. The scale-up of MTFBR is complicated by the ...
K. C. Koppenhoefer, J. Thomas, J. S. Crompton
AltaSim Technologies, LLC., Columbus, OH, USA
Computational tools based on the finite element method have been used extensively to develop solutions for elastic and elastic-plastic fracture mechanics problems. This work uses a small-scale yielding model to compare results developed from COMSOL Multiphysics® with another finite element modeling package and analytical solutions. Analysis are conducted for elastic, and elastic-plastic ...