Leiden, The Netherlands
A model for material damping is presented in terms of internal friction and in terms of a variation of stiffness. In the latter case the idea is that the stiffness increases if elastic energy is stored and decreases if elastic energy is released. In case of a single mass spring system “stiffness” refers to the stiffness of the spring; in case of a continues object ...
Variation of the Frost Boundary below Road and Railway Embankments in Permafrost Regions in Response to Solar Irradiation and Winds
N.I. Kömle and W. Feng
Space Research Institute, Austrian Academy of Sciences, Graz, Austria
State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China
We present COMSOL solutions for a coupled gas flow and heat transfer problem, which occurs particularly when traffic pathways are constructed in high altitude and arctic regions, where the underground is frozen soil. To avoid melting of the frozen ground (which usually leads to mechanical instability) one has to find suitable measures to keep the subsurface soil and the embankment suitably cool. ...
Minhee Jun, and Jason V. Clark
Departments of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
Large deflection actuators are becoming increasingly important for microsystems. Since actuation forces are usually small, large deflection actuators usually require flexures with low stiffness. Rectangular serpentine flexures are often used for such actuators due to their low stiffness and large linear deflection range. In this paper we investigate the performance of curved serpentine flexures ...
Fundamental Three Dimensional Modeling and Parameter Estimation of a Diesel Oxidation Catalyst for Heavy Duty Trucks
A. Holmqvist and C.U.I. Odenbrand
Department of Chemical Engineering, Faculty of Engineering, LTH, Lund University, Lund, Sweden
Mathematical optimization can be used as a computational engine to generate the best solution for a given problem in a systematic and efficient way. In the context of monolithic converter systems, the parameter estimation problem (or inverse problem) is solved using Partial Differential Equations (PDE)-based models of the physical system coupled with an optimization algorithm. These problems are ...
Simulo Technologies, Lagos, Nigeria
A qualitative flow analysis by numerical simulation of a fermentation process in a sorghum factory is presented. The simulations were done with the Numerical modeling software, COMSOL Multiphysics. Several flow arrangements were considered in the study and as a result, optimized flow configurations were evolved.
F. Cipitì, L. Pino, A. Vita, M. Laganà, and V. Recupero
The paper presents a two-dimensional model to describe the gas flow in a propane autothermal reactor, developed at the CNR-ITAE Institute, and aimed to design a Beta 5 kWe hydrogen generator, named HYGen II, to be used with Polymer Electrolyte Fuel Cells (PEFCs) for residential applications. The main aim of the mathematical model was to optimize the reactor geometrical key parameters (diameter ...
A. Schwen, G. Bodner, A. Schnepf, D. Leitner, G. Kammerer, and W. Loiskandl
Institute of Hydraulics and Rural Water Management, Univ. Natural Resour. Appl. Life Sci., BOKU, Wien, Austria
Institute of Agronomy and Plant Breeding, Univ. Natural Resour. Appl. Life Sci., BOKU, Wien, Austria
Institute of Soil Science, Univ. Natural Resour. Appl. Life Sci., BOKU, Wien, Austria
Modeling soil water dynamics requires an accurate description of soil hydraulic properties, i.e. the retention and hydraulic conductivity functions. Generally, these functions are assumed to be unchanged over time in most simulation studies. In this paper, we implemented temporal changes in the soil hydraulic properties in a Richards’ equation simulation of soil water dynamics. Based on ...
O. Nasir, M.Fall, T.S. Nguyen[1,2], and E. Evgin
Department of Civil Engineering, University of Ottawa, Ottawa, Ontario, Canada
Canadian Nuclear Safety Commission (CNSC), Ottawa, Ontario, Canada
The last glacial cycle in the Northern Hemisphere started approximately 120,000 year ago. During that cycle, Southern Ontario was buried under a continental ice cap, with a maximum thickness of up to 3km. The ice cap retreated approximately 10,000 years ago. The COMSOL Multiphysics code is used to model the physical processes of the impact of past glaciations on the evolution of hydraulic system ...
E. Gutierrez-Miravete, and J. Streeter
Department of Engineering and Science, Rensselaer at Hartford, Hartford, Connecticut, USA
Optiwind, Torrington, Connecticut, USA
The bearing and shaft are part of a safe and arm device constructed as an assembly by a multi-layer additive/subtractive plating and planarization processes (EFAB technology). Devices are constructed by a multi-layer additive/subtractive planarization process. This paper evaluates the lubricating flow between the shaft and journal of the MEMS bearing for seven configurations. The pressure ...
Institut für Mikrotechnik Mainz, Fluidik und Simulation, Mainz
The development of micro-TAS, Lab-on-a-Chip-systems and micro-reactors relies on the extensive use of computational fluid dynamics (CFD). The presentation aims to highlight specific µ-fluidic features, adequate simulation methods and benefits in context with the design of microfluidic systems. A case study discusses the modeling and characterization of a microfluidic device combining ...