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TONG, Lizhu. "J056054 3D Simulation of Jet Flow using COMSOL Multiphysics." Proceedings of Mechanical Engineering Congress, Japan 2011 (2011): _J056054–1—_J056054–2. http://dx.doi.org/10.1299/jsmemecj.2011._j056054-1.
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Lanin, V. L., V. T. Pham, and A. I. Lappo. "Through-silicon-via formation of 3D electronic modules by laser radiation." Doklady BGUIR 19, no. 3 (June 2, 2021): 58–65. http://dx.doi.org/10.35596/1729-7648-2021-19-3-58-65.
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Laser heating is a promising method for through-silicon-via (TSV) formation in assembling highdensity 3D electronic modules due to its high specific energy and local heating ability. Using laser radiation for the formation of TSV makes it possible to reduce its diameter, indirectly increases the density of elements in 3D electrical modules. Laser system selection depends on the physical and mechanical properties of the processed materials and on the technical requirements for laserprocessing. The reflectivity of most materials increases with the laser wavelength. It was found that with an increase in the initial temperature of the substrate, the TSV taper becomes larger. Simulation was performed in COMSOL Multiphysics 5.6 to conduct thermal distribution during TSV laser formation. By modeling thermal fields in the COMSOL Multiphysics 5.6 software for laser processing of silicon substrates and experimental studies, the parameters of laser radiation have been optimized to obtain a minimum hole taper coefficient in the substrates of 3D electronic modules. The optimal duration of exposure to laser radiation with a wavelength of 10.64 microns is less than 2 s with holes taper 0.1–0.2.
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Ismail, Zuhaila, Lim Yeou Jiann, Sabaruddin Ahmad Jamali, and Alistair Fitt. "Simulation of AH flows and deformation of DMD in a 3D AC." Malaysian Journal of Fundamental and Applied Sciences 13, no. 4-1 (December 5, 2017): 362–66. http://dx.doi.org/10.11113/mjfas.v13n4-1.898.
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This paper presents the interaction between the aqueous humour (AH) flows and the deformation of Descemet membrane detachment (DMD) in a 3D anterior chamber (AC). Arbitrary Lagrangian Eulerian (ALE) method is used to model the problem. Finite element method using COMSOL Multiphysics software is adopted to solve the governing equations for the AH flows and the deformation of DMD. The fluid flow behaviour and the deformation of the detached Descemet membrane are analysed in order to comprehend the progression of the DMD in the AC due to the AH flows and vice versa. The re-attachment or re-detachment of the DMD is significantly affected by the AH flows. Advance treatment for the DMD can be developed based on a better understanding of the interaction between the AH flows and the DMD.
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Ara, Iffat. "Numerical simulation of mathematical heart model in COMSOL." International Journal of Engineering & Technology 9, no. 1 (January 23, 2020): 77. http://dx.doi.org/10.14419/ijet.v9i1.30052.
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Electrical activity is essential for the cardiac cell to perform its function. Mathematical modeling of cardiac electrical activity is performed from the cell, tissue and organ levels through to the body surface level. The electrical activity of the cardiac as a whole is thus characterized by a complex multiscale structure. The most complete model of such a complex setting is the anisotropic bidomain model that consists of a system of two degenerate parabolic reaction diffusion equations describing the intra and extracellular potentials in the cardiac muscle, coupled with a system of ordinary deferential equations describing the ionic currents flowing through the cellular membrane. This study describes an anatomically realistic 3D Bidomain model of whole-heart electrical activity. The heart was embedded in a human torso, incorporating spontaneous activation with heterogeneous action potential (AP) morphologies throughout the heart. The aim of this study is the development of a geometrically simple and computationally efficient 3D model of heart. In this paper a finite element formulation, model and simulation of Bidomain equation has been conducted. The FitzHugh-Nagumo (FHN) equations were incorporated into Bidomain model of cardiac electrical activity, which was comprised of a simplified geometry of the whole heart with the torso as an extracellular volume conductor. Laplace equation for the torso also considered. Simplified 3D cardiac model was implemented using COMSOL Multiphysics 5.0 finite element software. Electrical potential at different point on torso is measured. Propagation of electrical excitation on heart surface is also observed. This study represents the first stage toward the development of an accurate computer model of heart activation.
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Bashir, Imran, and Michael Carley. "Development of 3D boundary element method for the simulation of acoustic metamaterials/metasurfaces in mean flow for aerospace applications." International Journal of Aeroacoustics 19, no. 6-8 (September 3, 2020): 324–46. http://dx.doi.org/10.1177/1475472x20954423.
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Low-cost airlines have significantly increased air transport, thus an increase in aviation noise. Therefore, predicting aircraft noise is an important component for designing an aircraft to reduce its impact on environmental noise along with the cost of testing and certification. The aim of this work is to develop a three-dimensional Boundary Element Method (BEM), which can predict the sound propagation and scattering over metamaterials and metasurfaces in mean flow. A methodology for the implementation of metamaterials and metasurfaces in BEM as an impedance patch is presented here. A three-dimensional BEM named as BEM3D has been developed to solve the aero-acoustics problems, which incorporates the Fast Multipole Method to solve large scale acoustics problems, Taylor’s transformation to account for uniform and non-uniform mean flow, impedance and non-local boundary conditions for the implementation of metamaterials. To validate BEM3D, the predictions have been benchmarked against the Finite Element Method (FEM) simulations and experimental data. It has been concluded that for no flow case BEM3D gives identical acoustics potential values against benchmarked FEM (COMSOL) predictions. For Mach number of 0.1, the BEM3D and FEM (COMSOL) predictions show small differences. The difference between BEM3D and FEM (COMSOL) predictions increases further for higher Mach number of 0.2 and 0.3. The increase in difference with Mach number is because Taylor’s Transformation gives an approximate solution for the boundary integral equation. Nevertheless, it has been concluded that Taylor’s transformation gives reasonable predictions for low Mach number of up to 0.3. BEM3D predictions have been validated against experimental data on a flat plate and a duct. Very good agreement has been found between the measured data and BEM3D predictions for sound propagation without and with the mean flow at low Mach number.
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Pettersen, Fred-Johan, and Jan Olav Høgetveit. "From 3D tissue data to impedance using Simpleware ScanFE+IP and COMSOL Multiphysics – a tutorial." Journal of Electrical Bioimpedance 2, no. 1 (July 23, 2019): 13–32. http://dx.doi.org/10.5617/jeb.173.
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Abstract Tools such as Simpleware ScanIP+FE and COMSOL Multiphysics allow us to gain a better understanding of bioimpedance measurements without actually doing the measurements. This tutorial will cover the steps needed to go from a 3D voxel data set to a model that can be used to simulate a transfer impedance measurement. Geometrical input data used in this tutorial are from MRI scan of a human thigh, which are converted to a mesh using Simpleware ScanIP+FE. The mesh is merged with electrical properties for the relevant tissues, and a simulation is done in COMSOL Multiphysics. Available numerical output data are transfer impedance, contribution from different tissues to final transfer impedance, and voltages at electrodes. Available volume output data are normal and reciprocal current densities, potential, sensitivity, and volume impedance sensitivity. The output data are presented as both numbers and graphs. The tutorial will be useful even if data from other sources such as VOXEL-MAN or CT scans are used.
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Pham, Khuong Thi Thao. "10 MHz Ultrasound Linear Array Design for Medical Application." Journal of Science and Technology: Issue on Information and Communications Technology 17, no. 12.2 (December 9, 2019): 1. http://dx.doi.org/10.31130/ict-ud.2019.90.
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This report represents a design and simulation of 10 MHz ultrasound transducer for medical application. The array is designed with 64 elements of 50µm width, 25µm kerf and 1mm elevation for each element. This results in the total transducer dimension of 1mm x 4.8mm. Piezoelectric material PZT 5H is chosen as the active layer while commercial materials named Ecosorb-MF116 and Polystyrene Fostarene-50 are chosen as two matching layers. Transducer’s 1D model using XTrans design toolbox and 3D FEM Comsol models (charge and voltage control) are investigated both accounted the effect of the 500nm electrode layers. Single element and array beam forming are calculated using Field II. A simulation of phantom imaging is observed using the transducer.
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Cui, Jun Hua, Wei Xu, and Zheng Hua Guo. "Coupled Thermo-Flowing 3D Steady State Model of Friction Stir Welding Process." Applied Mechanics and Materials 470 (December 2013): 325–29. http://dx.doi.org/10.4028/www.scientific.net/amm.470.325.
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The coupled thermo-flowing 3D steady-state model of friction stir welding model is established based on fluid mechanics. With analyzing the impact of pin shoulder and pin on heat producing, the model considers the influence of pin on the heat producing processing. The model applies viscoplastic constitutive equations to describe the material, and turbulence model to simulate the material flowing behavior. With the additional turbulence kinetic energy equations and flow boundary condition equations, the model is established. With Comsol Multiphysics finite analysis software, a process simulation was carried out, and the results reflect that the model can reveal the steady state characteristics of thermo and material flowing behavior of friction stir welding.
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Sun, Quan, Zong Fu Jiang, and Edmond Cretu. "Simulation and Characterization of a Novel Large Stroke Micromirror." Advanced Materials Research 403-408 (November 2011): 3411–17. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.3411.
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This paper reports on the simulation and characterization of a microelectromechanical system (MEMS) micromirror fabricated with PolyMUMPs. The overall diameter of the hexagonal micrimirror, including mirror plate and 3 supporting cantilevers fixed around, is 450um. A 3D model is built in finite element method (FEM) with COMSOL. Simulations of the elevated height of mirror plate, pull-in voltage and eigenfrequency of the micromirror are carried out. The static and dynamic performances of the fabricated micromirror are characterized by Veeco Optical Profiler and Polytek MEMS System Analyzer. The comparison between measurement and simulation exhibits good concordance. Surface topography measurement shows the elevated height and stress-induced concave deformation of mirror plate almost the same scale as demonstrated in FEM simulation. The Pull-In voltages are measured to be around 32V in current-voltage curve which is almost the same as in FEM simulation with one electrode biased. The fundamental resonant frequency is measured to be 4.3k Hz in torsional motion and 4.9k Hz in piston motion.
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Zhang, Shiwei, Ninghua Kong, Yufang Zhu, Zhijun Zhang, and Chenghai Xu. "3D Model-Based Simulation Analysis of Energy Consumption in Hot Air Drying of Corn Kernels." Mathematical Problems in Engineering 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/579452.
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To determine the mechanism of energy consumption in hot air drying, we simulate the interior heat and mass transfer processes that occur during the hot air drying for a single corn grain. The simulations are based on a 3D solid model. The 3D real body model is obtained by scanning the corn kernels with a high-precision medical CT machine. The CT images are then edited by MIMICS and ANSYS software to reconstruct the three-dimensional real body model of a corn kernel. The Fourier heat conduction equation, the Fick diffusion equation, the heat transfer coefficient, and the mass diffusion coefficient are chosen as the governing equations of the theoretical dry model. The calculation software, COMSOL Multiphysics, is used to complete the simulation calculation. The influence of air temperature and velocity on the heat and mass transfer processes is discussed. Results show that mass transfer dominates during the hot air drying of corn grains. Air temperature and velocity are chosen primarily in consideration of mass transfer effects. A low velocity leads to less energy consumption.
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Tulus, Tulus, Lamtiur Simbolon, Sawaluddin Sawaluddin, and T. J. Marpaung. "Optimization temperature in the room using air conditioner with finite element methods." MATEC Web of Conferences 197 (2018): 01009. http://dx.doi.org/10.1051/matecconf/201819701009.
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Room temperature is one of the problems in everyday life that is often discussed. One of the tools in regulating the temperature is Air Conditioner (AC). As is known, that the AC work process in cooling the room is the process of heat transfer. This study aims to find out how the AC works in regulating the temperature in a room. In the process, this research is accomplished by implementing finite element method on the energy transfer equation. Where the energy transfer equation is the partial differential used for heat transfer. In the finite element method, the flow field is broken down into a set of small fluid elements (discrete domains). In the solution, use it in three-dimensional space, then select the linear interpolation function for the 3D element, and derive the matrix and vector elements by the Galerkin method to obtain global equations. Results from computer-assisted studies show the temperature distribution in the room of COMSOL Multiphysic 5.0. Simulation results with COMSOL show that there is a correlation between AC location and solar radiation indoors against indoor temperature.
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Amini, M., H. Kalvøy, and Ø. G. Martinsen. "Finite element simulation of the impedance response of a vascular segment as a function of changes in electrode configuration." Journal of Electrical Bioimpedance 11, no. 1 (January 1, 2020): 112–31. http://dx.doi.org/10.2478/joeb-2020-0017.
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Abstract Monitoring a biological tissue as a three dimensional (3D) model is of high importance. Both the measurement technique and the measuring electrode play substantial roles in providing accurate 3D measurements. Bioimpedance spectroscopy has proven to be a noninvasive method providing the possibility of monitoring a 3D construct in a real time manner. On the other hand, advances in electrode fabrication has made it possible to use flexible electrodes with different configurations, which makes 3D measurements possible. However, designing an experimental measurement set-up for monitoring a 3D construct can be costly and time consuming and would require many tissue models. Finite element modeling methods provide a simple alternative for studying the performance of the electrode and the measurement set-up before starting with the experimental measurements. Therefore, in this study we employed the COMSOL Multiphysics finite element modeling method for simulating the effects of changing the electrode configuration on the impedance spectroscopy measurements of a venous segment. For this purpose, the simulations were performed for models with different electrode configurations. The simulation results provided us with the possibility of finding the optimal electrode configuration including the geometry, number and dimensions of the electrodes, which can be later employed in the experimental measurement set-up.
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Morales, Edith Obregón, Jose de Jesus Perez Bueno, Juan Carlos Moctezuma Esparza, Diego Marroquín García, Arturo Trejo Perez, Roberto Carlos Flores Romero, Juan Manuel Olivares Ramírez, et al. "Portable Hybrid Refrigerator Prototype for Agribusiness With Its 3D Real Physical Geometry Scanned and Transferred for Simulation Software." International Journal of Hyperconnectivity and the Internet of Things 5, no. 1 (January 2021): 78–97. http://dx.doi.org/10.4018/ijhiot.2021010105.
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A methodology that starts from the acquisition of real prototype geometries up to simulations to evaluate parameters, improvements, or performance under various conditions is proposed. The authors show a case study of a refrigerator with storage capacity for 50 kg of fruit solar-powered by photovoltaic panels, which reach a temperature of about 4°C. The refrigerator comprises two systems, vapor-compression, and Peltier. The methodology consisted of acquiring by a 3D laser scanner or coordinate measuring machine (CMM) and in some small complex items using 3D photogrammetry scanner. These data were transferred first as a CAD or solid works geometry and subsequently transferred to domains geometry useful for ANSYS or COMSOL simulation software. These models with high-resolution bring the simulations closer to real prototypes. Wireless sensors were installed for temperature and humidity monitoring. The analyses of the energy efficiencies of the prototype were performed. The photovoltaic system was for use in crop areas where there was no access to the urban electric network.
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Barka, Noureddine, Abderrazak El Ouafi, Ahmed Chebak, Philippe Bocher, and Jean Brousseau. "Study of Induction Heating Process Applied to Internal Gear Using 3D Model." Applied Mechanics and Materials 232 (November 2012): 730–35. http://dx.doi.org/10.4028/www.scientific.net/amm.232.730.
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The current paper is principally dedicated to the study of geometry and frequency effects for internal spur gears heated by induction. The overall work is realized by the simulation efforts performed on Comsol multi-physics software. The 3D model used during this study is built basing on coupling between Maxwell’s and heat transfer equations. This model is used to calculate the temperature profile in the gear in function of machine parameters. The module and the frequency are varied to determinate their effects. In fact, two gears having the same external diameter but different modules are exploited during this study and the frequency is varied from low to high level. The obtained results allow understanding the effect of module and frequency on the final temperature distribution. Finally, the optimal frequency value permitting to have the best temperature profile is found.
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Sattayasoonthorn, Preedipat, Jackrit Suthakorn, and Sorayouth Chamnanvej. "Sensitivity and packaging improvement of an LCP pressure sensor for intracranial pressure measurement via FEM simulation." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 5 (October 1, 2019): 4044. http://dx.doi.org/10.11591/ijece.v9i5.pp4044-4052.
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A biocompatible liquid crystal polymer (LCP) pressure sensor is proposed for measuring intracranial pressure (ICP) in Traumatic Brain Injury (TBI) patients. Finite element method using COMSOL multiphysics is employed to study the mechanical behavior of the packaged LCP pressure sensor in order to optimize the sensor design. A 3D model of the 8x8x0.2 mm LCP pressure sensor is simulated to investigate the parameters that significantly influence the sensor characteristics under the uniform pressure range of 0 to 50 mmHg. The simulation results of the new design are compared to the experimental results from a previous design. The result shows that reducing the thickness of the sensing membrane can increase the sensitivity up to six times of that previously reported. An improvement of fabrication methodology is proposed to complete the LCP packaging.
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Djekidel, R., and S. A. Bessedik. "ASA Algorithm Combined with Current Simulation Method (CSM) for the Magnetic Induction under HV Power Lines in 3D Analysis Model." Advanced Electromagnetics 9, no. 2 (August 28, 2020): 7–18. http://dx.doi.org/10.7716/aem.v9i2.1345.
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In this paper, a new hybrid approach to modeling the magnetic induction produced by HV overhead power line which combines the current simulation method (CSM) and adaptive simulated annealing algorithm (ASA) is discussed. The aim of the ASA algorithm is to find the optimal position and number of current loops used in bundles conductors for an accurate magnetic induction. Several parameters affecting the magnetic induction have been studied; it is observed that, taking into account the effect of conductor sag is much more interesting particularly at the mid-span length where the magnetic induction becomes very significant, the results also indicated that the maximum magnetic induction levels are less than the limits recommended by the ICNIRP standard for general public and occupational exposure. The calculated results are compared with those obtained from the COMSOL 4.3a Multiphysics software. A good agreement has been reached.
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Liu, Shuang, Zongjun Tian, Lida Shen, and Mingbo Qiu. "Numerical Simulation and Experimental Investigation of Laser Ablation of Al2O3 Ceramic Coating." Materials 13, no. 23 (December 2, 2020): 5502. http://dx.doi.org/10.3390/ma13235502.
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This paper presents an evaluation of the molten pool laser damage done to an Al2O3 ceramic coating. Mechanism analysis of the laser damage allowed for a 2D finite element model of laser ablation of the Al2O3 ceramic coating to be built. It consisted of heat transfer, laminar flow, and a solid mechanics module with the level set method. Results showed that the laser damage mechanisms through laser ablation were melting, gasification, spattering, and micro-cracking. The ablation depth and diameter increased with the increasing laser ablation time under continuous irradiation. The simulation profile was consistent with the experimental one. Additionally, the stress produced by the laser ablation was 3500–9000 MPa, which exceeded the tensile stress (350–500 MPa), and fracturing and micro-cracks occurred. Laser damage analysis was performed via COMSOL Multiphysics to predict laser damage morphology, and validate the 3D surface profiler and scanning electron microscope results.
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Morvarid, Masoud, Ali Rezghi, Alireza Riasi, and Mojtaba Haghighi Yazdi. "3D numerical simulation of laminar water hammer considering pipe wall viscoelasticity and the arbitrary Lagrangian-Eulerian method." World Journal of Engineering 15, no. 2 (April 9, 2018): 298–305. http://dx.doi.org/10.1108/wje-08-2017-0236.
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Purpose Analysis of fast transient flow in water pipe systems is an important issue for the prevention of unfavorable pressure oscillations and severe damage to the pipelines. This paper aims to present the performance of three-dimensional (3D) simulation of laminar water hammer caused by fast closure of valve. Design/methodology/approach The viscoelastic behavior of pipe wall is mathematically modeled by using the rheological model of Maxwell. The arbitrary Lagrangian–Eulerian (ALE) method is also used to simulate fluid–structure interaction. In this method, unlike the classical water hammer theory, the acoustic wave velocity is calculated during the numerical simulations and therefore it is not predetermined. Findings Investigating the velocity profiles and the shear stress diagrams for transient flow in elastic pipe showed that the strong effect of viscous forces on the near wall region in conjunction with the influence of inertial forces in the central region of the pipe leads to creation of reverse flow near the pipe wall. Comparing the numerical results obtained for elastic pipe with those of viscoelastic pipe revealed that during transient condition, the viscoelastic wall absorbs the energy of fluid and therefore pressure fluctuations of viscoelastic pipe are damped more quickly. Moreover, the 3D simulation of water hammer confirmed the plane wave hypothesis of water hammer. Originality/value The 3D Navier–Stokes equations are solved considering the viscoelasticity of the pipe and the ALE method using the software package of COMSOL Multiphysics.
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Abdullahi, M. B., and M. H. Ali. "DESIGN AND PERFORMANCE SIMULATION OF STRUCTURED MICROWAVE ABSORBER BASED ON CONDUCTIVE ABS 3D PRINTING FILAMENT." FUDMA JOURNAL OF SCIENCES 4, no. 4 (June 14, 2021): 425–31. http://dx.doi.org/10.33003/fjs-2020-0404-499.
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Electromagnetic absorbing materials with broadband, lightweight, wide-angle, and polarization-insensitive characteristics attracts extensive research interest recently, due to rapid advancement in radar detection techniques and communication devices. Three-dimensional printing is being employed to realize cost-effective structured electromagnetic absorbers that has lately become a common practice of improving radar stealth performance and shielding effectiveness. Structured absorbers permit realization of desired absorption characteristics by careful design of their geometrical structures. In this study, a two-layer structured microwave absorber using conductive ABS polymer is simulated. COMSOL Multiphysics environment is used to investigate the absorption characteristics of the designed structure. Under normal incidence, simulation results revealed at least 90% of absorption from 7.2 GHz to 18.0 GHz for both Transverse Electric (TE) and Transverse Magnetic (TM) polarizations. Oblique incidence results for TE polarization indicate that the absorption rate is more than 90% in the whole range of 7.2–18 GHz frequency band up to 450 while the absorption rate is more than 80% for 600 incident waves. The absorption rate is more than 90% in the 7.2-18 GHz range for oblique incidences of up to 300 only for TM polarization, but greater than 70% at 450 incident angles. Additionally, the designed absorber is independent of the polarization of the incident wave. As a result of the exhibited favourable absorption characteristics, the studied absorber provides great potentials for its experimentation and practicability using the low-cost 3D printing manufacturing process
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Narukullapati, Bharath Kumar, T. K. Bhattacharya, ANaveen Reddy, and Srikanth Gollapudi. "Modeling and simulation of Electromagnetic Fields on a Floating Aluminium." International Journal of Engineering & Technology 7, no. 4.24 (November 27, 2018): 148. http://dx.doi.org/10.14419/ijet.v7i4.24.21876.
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The electromagnetic field calculation for a floating aluminum disc is difficult to calculate since the equation involved does not produce a closed solution. The numerical, analytical, semi-analytical techniques that are already developed to find these magnetic fields have no proper mathematical formulation when the disc is disturbed from its coaxial position. The stabilization of disc is going to be effected when the disc moves away from its coaxial position due to a change in inductance between the disc and coils, due to change in magnetic flux linkage, etc. In this paper, a 2D FEM model is developed to determine the magnetic fields on a floatingaluminum disc when it is moved away from its coaxial position. The 3D FEM model developed is simulated in both COMSOL-Multiphysics and ANSYS-Electronics. The results obtained by simulation are compared, for accuracy, with the numerical solution developed earlier using Finite Difference method (FDM) and also discussed.
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Zhang, Jianfei, Chu Zhao, Hongyan Li, and Wenquan Tao. "3D Numerical Simulation of Heat Transfer of a Heated Plate under the Electric Field Generated by a Needle Electrode." Mathematical Problems in Engineering 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/354180.
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A three-dimensional numerical model that couples the electric field, velocity field, and temperature field is developed based on the commercial code COMSOL Multiphysics. The influences of several factors on convective heat transfer on a heated plate in the electric field generated by a needle electrode are observed. The factors are the applied voltage, the distance between the two electrodes, and the size of the ground plate. The results show that applied voltage is one of the most important factors for the convection heat transfer. The convection heat transfer efficiency significantly increases with the improvement of the applied voltage. From the perspective of the model size, the decrease of the distance between two electrodes and the size of the plate could improve the average convection heat transfer coefficient. Smaller ionic wind device needs lower applied voltage and less electric energy to obtain the same average convection heat transfer coefficient as the bigger one, which provides the theoretical basis for the potential of miniaturizing the ionic wind cooling device.
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Thai, Nguyen Thi, Chu Thi Xuan, Pham Duc Thanh, Mai Anh Tuan, and Nguyen Phuong Nhung. "Formation of Microdroplet in T-junction Microfluidic System: Experiment and Simulation." Communications in Physics 28, no. 3 (November 14, 2018): 225. http://dx.doi.org/10.15625/0868-3166/28/3/12530.
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The purpose of this study is to investigate the formation of the water droplet in oil using T-junction microfluidic device. Both numerical and experimental methods have been developed to explore the dependence of droplet size on the flow rate of two immiscible liquids as well as the system geometry. The velocity of droplet in channel is also considered. The microfluidic system was fabricated with lithography technique. The 3D simulation was performed based on COMSOL software using level set method. The size of droplet is inversely proportional to the flow rate of continuous phase according to exponential function, increases linearly with the flow rate of dispersed phase, and decreases as the width of lateral channel decreases. While the decreasing of the width of the lateral channel gives rise to the increasing of droplet velocity, the velocity of droplet depends linearly on the flow rate of disperse phase. A good consistence was observed between the theory and the experiment.
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Till, Zoltán, Bálint Molnár, Attila Egedy, and Tamás Varga. "CFD Based Qualification of Mixing Efficiency of Stirred Vessels." Periodica Polytechnica Chemical Engineering 63, no. 1 (July 10, 2018): 226–38. http://dx.doi.org/10.3311/ppch.12245.
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In this work, we focus on the most crucial units in a chemical technology, the chemical reactors. Using a commercially available CFD software package, COMSOL Multiphysics, 3D mathematical models of a batch reactor with different impeller geometries have been investigated. The reasonable agreement between the experimental and simulation results indicates the validity of the developed CFD model. The effect of the impeller design, e. g. number of blades on the mixing efficiency is evaluated based on the simulation studies. The proposed measure to determine the energy efficiency of mixing (i. e. mixing index) is based on the calculated velocity field and energy usage. The information about the homogeneity of the mixed phase in the system can be extracted from the developed velocity field. Hence, we proposed histograms of velocity fluctuations on a logarithmic scale as an efficient tool to measure the achieved homogeneity of the phase in case of different impellers and rotational speeds.
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Patel, Yatinkumar, Giedrius Janusas, Arvydas Palevicius, and Andrius Vilkauskas. "Development of Nanoporous AAO Membrane for Nano Filtration Using the Acoustophoresis Method." Sensors 20, no. 14 (July 9, 2020): 3833. http://dx.doi.org/10.3390/s20143833.
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A concept of a nanoporous anodic aluminum oxide (AAO) membrane as a vibro-active micro/nano-filter in a micro hydro mechanical system for the filtration, separation, and manipulation of bioparticles is reported in this paper. For the fabrication of a nanoporous AAO, a two-step mild anodization (MA) and hard anodization (HA) technique was used. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to analyze the surface morphology of nanoporous AAO. A nanoporous structure with a pore diameter in the range of 50–90 nm, an interpore distance of 110 nm, and an oxide layer thickness of 0.12 mm with 60.72% porosity was obtained. Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDS) were employed to evaluate AAO chemical properties. The obtained results showed that the AAO structure is of hexagonal symmetry and showed where Al2O3 is dominant. The hydrophobic properties of the nanoporous surface were characterized by water contact angle measurement. It was observed that the surface of the nanoporous AAO membrane is hydrophilic. Furthermore, to determine whether a nanomembrane could function as a vibro-active nano filter, a numerical simulation was performed using COMSOL Multiphysics 5.4 (COMSOL Inc, Stockholm, Sweden). Here, a membrane was excited at a frequency range of 0–100 kHz for surface acoustics wave (SAW) distribution on the surface of the nanoporous AAO using a PZT 5H cylinder (Piezo Hannas, Wuhan, China). The SAW, standing acoustic waves, and travelling acoustic waves of different wavelengths were excited to the fabricated AAO membrane and the results were compared with experimental ones, obtained from non-destructive testing method 3D scanning vibrometer (PSV-500-3D-HV, Polytec GmbH, Waldbronn, Germany) and holographic interferometry system (PRISM, Hy-Tech Forming Systems (USA), Phoenix, AZ, USA). Finally, a simulation of a single nanotube was performed to analyze the acoustic pressure distribution and time, needed to center nanoparticles in the nanotube.
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Gomez, Houari Cobas, Jéssica Gonçalves da Silva, Jocasta Mileski Machado, Bianca Oliveira Agio, Francisco Jorge Soares de Oliveira, Antonio Carlos Seabra, and Mario Ricardo Gongora-Rubio. "LTCC 3D FLOW FOCALIZATION DEVICE FOR LIQUID-LIQUID PARTIAL SOLVENT EXTRACTION." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, CICMT (May 1, 2016): 000111–17. http://dx.doi.org/10.4071/2016cicmt-wa23.
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Abstract The present work shows a ceramics microfluidic device for partial solvent extraction scheme. The technology used for device fabrication was Low Temperature Cofired Ceramics (LTCC) which allows us for complex and chemical resistant 3D microfluidic devices. The proposed system aims to partially extract the solvent present in a mixture containing aqueous and organic phases. This scheme uses a 3D flow focalization in order to improve the solvent diffusion into the external aqueous phase. The device is composed by three different parts, the input channels distribution, the main channel and the output channels distribution. The designed input channels distribution ensures a centered 3D focalized solvent stream along the main channel. The focalized solvent mixes with the surrounding water thanks to diffusion. Projected output channels take the central fluid out separately from the surrounding. Thus the device has two different outputs, one for the focalized fluid and another one for the waste fluid, which is the aqueous phase plus solvent. For a device concept proof, acetone and water were used as organic and aqueous phases, respectively. COMSOL Multiphysics was used for device microfluidics and chemical transport simulation. The extraction efficiency was the variable used as indicator for device performance validation. The flow rate ratio between phases, total flow rate, main channel length and focalized stream channel output hydraulic diameter (ODH) were used as process variables for simulation purposes. A factorial experimental planning was used in order to analyze the extraction efficiency taking into account process variables effects. From simulation results it was determined main channel length and ODH as the variables with stronger effect on extraction efficiency. Obtained simulated efficiencies were as high as 80.6%. Considering previous results observations a microfluidic device was fabricated with a main channel length of 21,4 mm and ODH of 214,63 μm. Gas chromatography was used to measured acetone concentration in outputs samples and from here the extraction efficiency. Experimental results were in agreement with simulation, returning extraction efficiencies in the order of 80.8% ± 2.2%.
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Alsharif, Sarah, Hanaa Farhan, and Hala Al-Jawhari. "Effect of patterning on the performance of p-type Cu2O TFTs: a 3D simulation using COMSOL multiphysics." European Physical Journal Applied Physics 77, no. 1 (January 2017): 10102. http://dx.doi.org/10.1051/epjap/2016160293.
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Abdelkrim, Mourad, Mourad Brioua, Abderrahim Belloufi, and Abdelhafid Gherfi. "Experimental and Numerical Study of the Cutting Temperature during the Turning of the C45 Steel." Applied Mechanics and Materials 823 (January 2016): 507–12. http://dx.doi.org/10.4028/www.scientific.net/amm.823.507.
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In machining operation, the quality of surface finish is an important requirement for many turned work pieces. cutting temperature is one of the most important parameters in determining the cutting performance and tool life. the objective for this work is to estimate the cutting temperature in 3D model on tool-chip interface and the interface temperature during turning process, using the digital simulation software COMSOL Multiphysics.The tool–chip interface temperature results obtained from experimental results by using C45 medium carbon steel work piece with natural contact tools, without the application of cooling and lubricating agents and a K type thermocouple technique was used for estimating cutting temperatures in a turning operation.This procedure facilitates the determination of the temperature at tool-chip interface in dry turning process, which is still a challenge for existing experimental and numerical methods.
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Yashvanth, Varshitha, and Sazzadur Chowdhury. "An Investigation of Silica Aerogel to Reduce Acoustic Crosstalk in CMUT Arrays." Sensors 21, no. 4 (February 19, 2021): 1459. http://dx.doi.org/10.3390/s21041459.
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This paper presents a novel technique to reduce acoustic crosstalk in capacitive micromachined ultrasonic transducer (CMUT) arrays. The technique involves fabricating a thin layer of diisocyanate enhanced silica aerogel on the top surface of a CMUT array. The silica aerogel layer introduces a highly nanoporous permeable layer to reduce the intensity of the Scholte wave at the CMUT-fluid interface. 3D finite element analysis (FEA) simulation in COMSOL shows that the developed technique can provide a 31.5% improvement in crosstalk reduction for the first neighboring element in a 7.5 MHz CMUT array. The average improvement of crosstalk level over the −6 dB fractional bandwidth was 22.1%, which is approximately 5 dB lower than that without an aerogel layer. The results are in excellent agreement with published experimental results to validate the efficacy of the new technique.
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Iatcheva, Ilona, Malina Dimitrova, and Nikolina Petkova. "3D modelling of electric field in vicinity of 400 kV power line." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, no. 4 (July 2, 2018): 1545–55. http://dx.doi.org/10.1108/compel-09-2017-0381.
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Purpose The purpose of this study is to model the electric field distribution in 3D in the vicinity of 400 kV power line to determine the field impact on the environment and on the human body depending on the person location and presence of other objects. Design/methodology/approach The real 3D geometry of the three-phase line because of the line sag presence and existence of additional objects in its vicinity is considered. The time-harmonic electric field has been modeled, taking into account 1,200 phase shifting between the three-phase, 50 Hz currents. The study has been carried out using the finite element method (FEM) and COMSOL Multiphysics 5.2 software package. Special attention was paid to the field at a height of 2 m from the ground, to estimate the field influence on the located human body in the studied area (in relation to the limits for permissible electric field values). Findings 3D map of electric field in the line vicinity and the electric field strength distribution along the observation surface (2 m from the ground) are determined for several region configurations: without additional objects, human presence just under the line, human at a certain distance from the line and presence of human and a tree. The simulation model was validated on the basis of comparison with computed and experimental data presented in the literature. Originality/value 3D FEM modeling makes it possible to consider the real environment configuration, presence of line sag and additional objects with different material properties and obtaining of field quantities at any point of observation.
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Dallah, Khalid, A. Bellel, O. C. Lezzar, Salah Sahli, and Patrice Raynaud. "Modeling of Interdigital Electrodes Geometrical Parameters Effects on Chemical Sensor Response." Key Engineering Materials 826 (October 2019): 67–72. http://dx.doi.org/10.4028/www.scientific.net/kem.826.67.
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The detection of volatile organic compounds (VOCs), humidity and toxic industrial chemicals is important for various environmental and industrial applications. The design of interdigital capacitor (IDCs) sensor is carried out in such a way that it would be suitable for microelectronic technology. The basic geometry of IDCs is defined by some parameters such as: number of electrodes N, electrode width W, electrode length L and the separation between electrodes G. The interactions between IDCs sensitive coating and analyte induced a change in the sensors capacitance due to the permittivity variation of the sensitive layer and to the change in polymer thickness (swelling). In this work, a fairly new approach of IDCs based sensor in terms of capacitance calculation has been presented. The results have been obtained from the modeling of the sensors geometry 2D and 3D using multi-physics simulation software COMSOL. The effects of some geometry parameters coupled with swelling measurements for polymeric films have been studied.
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Ghosh, Shajib, Mamun Rabbani, and ASM Shamsul Arefin. "A Simulation Based Study for the Early Detection of Glaucoma Using Temperature Profiling of Human Eye." Dhaka University Journal of Science 68, no. 1 (January 30, 2020): 37–44. http://dx.doi.org/10.3329/dujs.v68i1.54595.
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Glaucoma is one of the leading ophthalmologic disorders worldwide which results in irreversible blindness if left untreated. Although many detection techniques are already in use, they prove to detect glaucoma at a later stage when the disease causes irreversible effects to the optic tissue. This work aims at developing a novel technique to detect the presence and progression of glaucoma at an early stage through temperature profiling of optic tissues by LASER radiation. A 3D CAD model of the real human eye designed in SolidWorksTM was used and different parameter values were defined for performing thermal simulation in COMSOL Multiphysics® for three distinct LASER point sources: 694.3 nm Ruby LASER, 1064 nm Nd:YAG LASER and 1340 nm Nd:YAP LASER. By analyzing the thermal profile obtained from the simulation, an inverse trend of temperature variation with progression of glaucoma was observed. The effect was most prominently observed in using 694.3mm Ruby LASER with no such temperature rise in the eye causing any physiological harm. This work shows the possibility of using temperature profile due to irradiated light on human eye as a novel biomarker for the early detection of glaucoma.
Dhaka Univ. J. Sci. 68(1): 37-44, 2020 (January)
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Achour, Bilel, Ghada Attia, Chouki Zerrouki, Najla Fourati, Kosai Raoof, and Nourdin Yaakoubi. "Simulation/Experiment Confrontation, an Efficient Approach for Sensitive SAW Sensors Design." Sensors 20, no. 17 (September 3, 2020): 4994. http://dx.doi.org/10.3390/s20174994.
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Sensitivity is one of the most important parameters to put in the foreground in all sensing applications. Its increase is therefore an ongoing challenge, particularly for surface acoustic wave (SAW) sensors. Herein, finite element method (FEM) simulation using COMSOL Multiphysics software is first used to simulate the physical and electrical properties of SAW delay line. Results indicate that 2D configuration permits to accurately obtain all pertinent parameters, as in 3D simulation, with very substantial time saving. A good agreement between calculation and experiment, in terms of transfer functions (S21 spectra), was also shown to evaluate the dependence of the SAW sensors sensitivity on the operating frequency; 2D simulations have been conducted on 104 MHz and 208 MHz delay lines, coated with a polyisobutylene (PIB) as sensitive layer to dichloromethane (DCM). A fourfold increase in sensitivity was obtained by doubling frequency. Both sensors were then realized and tested as chem-sensors to detect zinc ions in liquid media. 9-{[4-({[4-(9anthrylmethoxy)phenyl]sulfanyl} methyl)]methyl] anthracene (TDP-AN) was selected as the sensing layer. Results show a comparable response curves for both designed sensors, in terms of limit of detection and dissociation constants Kd values. On the other hand, experimental sensitivity values were of the order of [7.0 ± 2.8] × 108 [°/M] and [16.0 ± 7.6] × 108 [°/M] for 104 MHz and 208 MHz sensors, respectively, confirming that the sensitivity increases with frequency.
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Long, Xing-ming, Rui-jin Liao, and Jing Zhou. "Numerical Simulation on Electrical-Thermal Properties of Gallium-Nitride-Based Light-Emitting Diodes Embedded in Board." Advances in OptoElectronics 2012 (October 24, 2012): 1–6. http://dx.doi.org/10.1155/2012/495981.
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The electrical-thermal characteristics of gallium-nitride- (GaN-) based light-emitting diodes (LED), packaged by chips embedded in board (EIB) technology, were investigated using a multiphysics and multiscale finite element code, COMSOL. Three-dimensional (3D) finite element model for packaging structure has been developed and optimized with forward-voltage-based junction temperatures of a 9-chip EIB sample. The sensitivity analysis of the simulation model has been conducted to estimate the current and temperature distribution changes in EIB LED as the blue LED chip (substrate, indium tin oxide (ITO)), packaging structure (bonding wire and chip numbers), and system condition (injection current) changed. This method proved the reliability of simulated results in advance and useful material parameters. Furthermore, the method suggests that the parameter match on Shockley's equation parameters, Rs, nideal, and Is, is a potential method to reduce the current crowding effect for the EIB LED. Junction temperature decreases by approximately 3 K to 10 K can be achieved by substrate thinning, ITO, and wire bonding. The nonlinear-decreasing characteristics of total thermal resistance that decrease with an increase in chip numbers are likely to improve the thermal performance of EIB LED modules.
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Yang, Dan, Yan-jun Liu, Bin Xu, and Yun-hui Duo. "A Blood Flow Volume Linear Inversion Model Based on Electromagnetic Sensor for Predicting the Rate of Arterial Stenosis." Sensors 19, no. 13 (July 8, 2019): 3006. http://dx.doi.org/10.3390/s19133006.
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This paper presents a mathematical model of measuring blood flow based on electromagnetic induction for predicting the rate of arterial stenosis. Firstly, an electrode sensor was used to collect the induced potential differences from human skin surface in a uniform magnetic field. Then, the inversion matrix was constructed by the weight function theory and finite element method. Next, the blood flow volume inversion model was constructed by combining the induction potential differences and inversion matrix. Finally, the rate of arterial stenosis was predicted based on mathematical relationship between blood flow and the area of arterial stenosis. To verify the accuracy of the model, a uniform magnetic field distribution of Helmholtz coil and a 3D geometric model of the ulnar artery of the forearm with different rates of stenosis were established in COMSOL, a finite element analysis software. Simulation results showed that the inversion model had high accuracy in the measurement of blood flow and the prediction of rate of stenosis, and is of great significance for the early diagnosis of arterial stenosis and other vessel diseases.
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Ahmed, Sayed Parvez, M. Abdul Kadir, Golam Dastegir Al Quaderi, Rubina Rahman, and K. Siddique E. Rabbani. "Improved Understanding of the Sensitivity of Linear Tetrapolar Impedance Measurement (TPIM) and 8-Electrode Focused Impedance Method (FIM) in a Volume Conductor." Bangladesh Journal of Medical Physics 8, no. 1 (September 10, 2017): 22–31. http://dx.doi.org/10.3329/bjmp.v8i1.33931.
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Tetrapolar Impedance Measurement (TPIM) is a 4-electrode impedance measurement system appropriate for a volume conductor in which current is driven through a pair of electrodes while potential developed across another pair of electrodes is measured to provide a value of transfer impedance. The 8-electrode Focused Impedance Method (FIM-8) consists of two concentric and orthogonal linear TPIM systems with their transfer impedances added for the purpose of localizing the central zone. Detailed 3D sensitivity studies are necessary for proper application of the techniques in specific biomedical applications and most reported work present point sensitivity distributions. The present work mainly focuses on planar average sensitivity in planes parallel to the electrode plane and its variation with depth due to different combinations of electrode separations both for current drive pair and the potential measuring pair. This was obtained through finite element simulation using COMSOL Multiphysics software for a 40x40x40cm3 volume. The results give useful information that can be used to design electrode configurations and measurement modalities for various applications.Bangladesh Journal of Medical Physics Vol.8 No.1 2015 22-31
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Laaouatni, Amine, Nadia Martaj, Rachid Bennacer, Mohamed El Omari, Liu Bin, Mohammed El Ganaoui, and Abdelatif Merabtine. "Integration of the PCM with intra-ventilation for improved thermal and inertial characteristics of the building envelope." European Physical Journal Applied Physics 84, no. 3 (December 2018): 30901. http://dx.doi.org/10.1051/epjap/2018180199.
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Several solutions based on phase change materials (PCM) are used for the thermal regulation of buildings. In this study, a combination of the inertial effect of PCM and intra-ventilation regulation is proposed. The purpose is to increase the thermal inertia of the building envelope leading to a fast passive and active cooling of the indoor environment. The principle of the solution is the use of a polymer-stabilized paraffin in external walls integrating ventilation pipes. For that, an experimental study of a hollow concrete block with PCM and ventilation tubes is conducted to test its thermal response. Gathered to this part, a 3D numerical model is developed under COMSOL Multiphysics®. The obtained simulation results are in good agreement with the experimental data. A parametric study is then performed including its actual characteristics against several conditions; it is revealed that the use of PCM gathered to the ventilation tubes enhances the thermal phase shift. It is stated that the forced ventilation through the tubes makes it possible to manage the energy and contribute to the renewal of the air.
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Sharma, Rashmi, Rekha Agarwal, Ashwani Kumar Dubey, and Anil Arora. "Design and Analysis of Capacitive Micromachined Ultrasonic Transducer." Recent Patents on Engineering 13, no. 2 (May 27, 2019): 108–16. http://dx.doi.org/10.2174/1872212112666180214141506.
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Background:Objective:To simulate a Micromechanical systems (MEMS) based CMUT working as a transmitter with the existing design and provide comparison within the possible architectural geometries.Methods:FEM simulation software COMSOL is used to simulate the 3D model of the transducer radiating in the air. The classical thin-plate theory is employed to solve for CMUT with a circular shape which is sufficient when the ratio of the diameter to thickness of the plate is very large, an aspect common in CMUTs. The Galerkin-weighted residual technique is used to get a solution for thin plate equation with the presumption that the deflections are small in comparison to the thickness of the plate.Results:The resonant frequency of CMUT with different geometries have been calculated. The deflection of membrane with applied DC bias is shown along with collapse voltage calculation. The generated ultrasound is shown with the AC bias superimposed on the DC bias. The capacitance change with the increasing DC voltage is discussed. The deflection of membrane is maximum as the resonance frequency is proved.Conclusion:The review of Capacitive Micromachined Ultrasonic Transducer architectures with different shapes is highlighted. The working behavior of CMUT with suitable dimension is simulated in 3D providing researcher data to wisely choose the CMUT prior to the fabrication. The CMUT is prioritized on various characteristics like wafer area utilization, deflection percentage within the cavity and durability of the transducer.
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Esman, A. K., G. L. Zykov, V. A. Potachits, and V. K. Kuleshov. "Simulation of Photovoltaic Thermoelectric Battery Characteristics." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 64, no. 3 (June 4, 2021): 250–58. http://dx.doi.org/10.21122/1029-7448-2021-64-3-250-258.
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Solar radiation is an environmentally friendly and affordable energy source with high release of energy. The use of a photovoltaic thermoelectric battery makes it possible to increase the efficiency of converting solar and thermal radiation into electrical energy, both on serene and cloudy days. An original battery structure with photovoltaic and thermoelectric converters is proposed. The 3D model of the proposed photovoltaic thermoelectric battery was realized in the COMSOL Multiphysics software environment with the use of a heat transfer module. The simulation was performed for the geographical coordinates of Minsk and taking into account the diurnal and seasonal variations of both the ambient temperature and the power density of the concentrated AM1.5 solar spectrum, the maximum value of which being varied from 1 to 500 kW/m2. The dependences of the maximum temperature values of the photovoltaic thermoelectric battery and the thermoelectric converters as well as temperature gradient patterns in the thermoelectric converters have been calculated. The dependences of the maximum temperature gradient values inside the thermoelectric converters on the solar power density are obtained. The graphs of the temperature gradients inside the thermoelectric converters of the photovoltaic thermoelectric battery by concentrated solar radiation versus the time of day in the middle of July and January are provided. It is shown that the output voltage increases up to the maximum values of 635 and 780 mV, respectively, in January and in July were achieved due to the temperature stabilization of the back side of the external electrodes of the proposed device
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Xiong, Feng, Chu Zhu, and Qinghui Jiang. "A Novel Procedure for Coupled Simulation of Thermal and Fluid Flow Models for Rough-Walled Rock Fractures." Energies 14, no. 4 (February 11, 2021): 951. http://dx.doi.org/10.3390/en14040951.
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An enhanced geothermal system (EGS) proposed on the basis of hot dry rock mining technology has become a focus of geothermal research. A novel procedure for coupled simulation of thermal and fluid flow models (NPCTF) is derived to model heat flow and thermal energy absorption characteristics in rough-walled rock fractures. The perturbation method is used to calculate the pressure and flow rate in connected wedge-shaped cells at pore-scale, and an approximate analytical solution of temperature distribution in wedge-shaped cells is obtained, which assumes an identical temperature between the fluid and fracture wall. The proposed method is verified in Barton and Choubey (1985) fracture profiles. The maximum deviation of temperature distribution between the proposed method and heat flow simulation is 13.2% and flow transmissivity is 1.2%, which indicates the results from the proposed method are in close agreement with those obtained from simulations. By applying the proposed NPCTF to real rock fractures obtained by a 3D stereotopometric scanning system, its performance was tested against heat flow simulations from a COMSOL code. The mean discrepancy between them is 1.51% for all cases of fracture profiles, meaning that the new model can be applicable for fractures with different fracture roughness. Performance analysis shows small fracture aperture increases the deviation of NPCTF, but this decreases for a large aperture fracture. The accuracy of the NPCTF is not sensitive to the size of the mesh.
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Mandal, Mithun, and Ramakrishna Bag. "Effect of pile and heat exchanger properties on total heat extraction of an energy pile - A numerical study." E3S Web of Conferences 205 (2020): 05024. http://dx.doi.org/10.1051/e3sconf/202020505024.
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Geothermal energy is one of the potential energy resources to meet future energy demand keeping environmental pollution under control. This paper presents the use of geothermal energy for space heating from energy pile. An energy pile with a single U tube heat exchanger of polyethylene (PE) pipe was modeled in this study. The effect of pile and heat exchanger properties on the total heat extraction was studied by the finite element analysis using COMSOL Multiphysics. The 3D model was developed and validated based on the literature reported results of an experimental thermal performance of a borehole equipped with a single and double U tube heat exchanger. Tetrahedral elements were considered for simulation of a 3D model. The model of a single energy pile of certain dimensions with different soil layers was considered, each soil layers were associated with different temperature. The effect of various parameters such as the length of concrete pile, the diameter of concrete pile, the thickness of U pipe, the inner diameter of U pipe and velocity of fluid inside the U pipe on amount of heat extraction was studied for an energy pile equipped with a single U tube heat exchanger. It was observed that the most influential parameters in increasing the outlet temperature of the heat exchanger loop are the diameter of the concrete pile, the inner diameter of U pipe and the velocity of fluid inside the U pipe.
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Halas, Dragan, Oskar Bera, Radovan Omorjan, Aleksandar Rajic, and Danijela Jasin. "Analysis of new forms of orifice plates using computational fluid dynamics." Chemical Industry 73, no. 5 (2019): 311–23. http://dx.doi.org/10.2298/hemind190722030h.
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In many technologies, such as process industry or water supply, there is a need to measure fluid flowrates. Orifice plates are the most common instruments for measuring the fluid flowrate through pipelines due to their many advantages. On the other side, their use increases operating costs of industrial plants and pipelines. In this work, three new forms of orifice plates were designed and tested. These new forms and one standard, which served as a reference, were designed by using the SolidWorks software package. The aim of the new designs was energy savings, and consequently reduction of operating costs. Energy savings can be achieved by such a design, which decreases the orifice plate resistance an element of the pipeline. This was achieved by increasing the open part of the orifice plate permitting the fluid flow. CAD models of orifice plates were transferred to STL files that were further used for CFD simulation as well as 3D printing of experimental replicas. According to the proposed algorithm, the new designs were tested by CFD simulation performed in the COMSOL Multiphysics software package, by using a finite-difference method. Equations used were based on the Reynolds form of Navier-Stokes equations (RANS, Reynolds-averaged Navier-Stokes), and the continuity equation for incompressible fluids. Next, as we have proposed in our algorithm of development of new orifice plate designs, experimental orifice plates were made by using 3D printing technology and FDM (Fused Deposition Modeling) procedure and tested at laboratory conditions. The results of laboratory tests were compared with the results of CFD simulation. A considerable amount of energy saving was indicated, which was achieved already by the first of the three new orifice plate forms (V1) as compared to the reference (V0). For the other two proposed forms, the effect of energy savings was considerably lower. By using CFD simulation, data can be obtained based on which a decision can be made whether the new shape of the measuring device should be corrected or is appropriate for further laboratory tests. Based on the presented results it can be concluded that the proposed testing algorithm proved useful in designing new forms of orifice plates.
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Hadi, Nabipour Afrouzi, Zulkurnain Abdul-Malek, Saeed Vahabi Mashak, and A. R. Naderipour. "Three-Dimensional Potential and Electric Field Distributions in HV Cable Insulation Containing Multiple Cavities." Advanced Materials Research 845 (December 2013): 372–77. http://dx.doi.org/10.4028/www.scientific.net/amr.845.372.
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Cross-linked polyethylene is widely used as electrical insulation because of its excellent electrical properties such as low dielectric constant, low dielectric loss and also due to its excellent chemical resistance and mechanical flexibility. Nevertheless, the most important reason for failure of high voltage equipment is due to its insulation failure. The electrical properties of an insulator are affected by the presence of cavities within the insulating material, in particular with regard to the electric field and potential distributions. In this paper, the electric field and potential distributions in high voltage cables containing single and multiple cavities are studied. Three different insulating media, namely PE, XLPE, and PVC was modeled. COMSOL software which utilises the finite element method (FEM) was used to carry out the simulation. An 11kV underground cable was modeled in 3D for better observation and analyses of the generated voltage and field distributions. The results show that the electric field is affected by the presence of cavities in the insulation. Furthermore, the field strength and uniformity are also affected by whether cavities are radially or axially aligned, as well as the type of the insulating solid. The effect of insulator type due the presence of cavities was seen most prevalent in PVC followed by PE and then XLPE.
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Robert, Femi, Anita Agrawal, and Shibu Clement. "Effect of Anode Temperature and Contact Voltage on the Design of Arc- Less Micro Electrical Contact." Micro and Nanosystems 11, no. 1 (April 2, 2019): 47–55. http://dx.doi.org/10.2174/1876402911666181214143451.
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Objective: This paper presents the effect of anode temperature and contact voltage on the breakdown arc of micro electrical contact pair under DC excitation. Methods: A rectangular micro electrical contact pair is considered. The resistance and capacitance of the contact pair are obtained for the materials Al, Cu, Au and Pt. The anode temperature is calculated based on the 3D heat equation. Pre-breakdown arc due to anode temperature is analyzed. Result: The breakdown voltage and breakdown electric field characteristics for the gap between 0.5µm and 30µm are reported. The electric field of micro electrical contact pair is analyzed mathematically. The calculated values of resistance, anode temperature and electric field are compared with the simulation results obtained using COMSOL multiphysics FEA software tool. The arc-less operating region of micro contact is identified. Four cases with the ratings 50V/5A, 50V/0.5A, 400 V/ 5A and 400V/0.5A have been considered for the analysis of arcless micro electrical contact. Conclusion: These results can be considered while designing arc-less micro electrical switches, micro relays and micro circuit breakers which can be applicable for the future DC electric power distribution, protection system and automobiles. Also these results can be considered when designing micro actuators, sensors and electrostatic devices.
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Zhao, Jingyao, and Yingchun Cai. "A comprehensive mathematical model of heat and moisture transfer for wood convective drying." Holzforschung 71, no. 5 (May 1, 2017): 425–35. http://dx.doi.org/10.1515/hf-2016-0148.
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Abstract The focus of this study is the development of a specific drying model for the design and operation of drying systems for stacked lumber in drying chambers. Namely, a comprehensive three-dimensional (3D) mathematical model of heat and moisture transfer in stacked wood has been developed, where the wood was subjected to convective drying that accounts for the effect of the surrounding fluid flow. In developing the model, the characteristics of wood and fluid flow, i.e. velocity, pressure, temperature, relative humidity (RH) and moisture content (MC) are described by the conservation equations of mass, momentum and energy as well as thermodynamic relations. The model presented was solved numerically by means of the commercial software COMSOL Multiphysics. The simulation results were validated against experimental data under laboratory conditions. Air current circulation was found to be non-uniform during drying, which accounts for the different rates of temperature and MC in wood. At the initial stage of drying, this difference was relatively large but reduced gradually with the drying process. Meanwhile, the transient gathered phenomenon related to humidity around the stacked wood in the chamber was observed in response to air current circulation and evaporation rate of moisture. Finally, sources of error incurred in numerical calculations and actual detection were identified and discussed.
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Tikhonov, A. I., A. V. Stulov, I. S. Snitko, and A. V. Podobnyj. "Development of 2D models of the magnetic field for digital twin technology and generative design of power transformers." Vestnik IGEU, no. 3 (June 30, 2020): 32–43. http://dx.doi.org/10.17588/2072-2672.2020.3.032-043.
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The development of generative design technologies that solve the problems of structural optimization and digital twins, that is simulation models of devices with at least 95 % accuracy, is an urgent task. These tech-nologies are usually implemented on the basis of 3D models of physical fields, for example, using ANSYS Maxwell or COMSOL Multiphysics packages, which are demanding in terms of computer resources and de-signer skills. However, the sufficient accuracy for transformer digital twins can be achieved using chain and 2D field models. The article aims to develop the models to calculate the transformer with the accuracy and ability to take into account the design features of a particular device, which is characteristic of digital twins. This can be used in generative design of transformers and in the study of their operation modes. The finite element method implemented via the authoring EMLib library which allows calculating magnetic fields in a 2D formulation was used. The simulation methods using the MatLab Simulink SymPowerSystem package were also employed. The assumptions made during the power transformer simulation have been estimated. They include the possibility of using chain and 2D field models without taking into account the steel anisotropy with Dirichlet boundary conditions when calculating the scattering fluxes. 2D field models have been developed for calculating the main flux and scattering fluxes, which are able to form the basis for digital twin technology and generative design of transformers. A simulation model of a transformer implemented in MatLab Simulink has been provided. The possibility of using the models for diagnosing transformer faults has been demonstrated. The simulation results of a transformer with a defect have been presented. The results obtained can be used in the development of transformers to search for optimal designs and to study the results of design decisions without creating prototypes. The findings can also be applied while operating the transformers to assess the damage and failures without dismantling and according to the test results.
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Luo, Yun Mei, Luc Chevalier, Francoise Utheza, and Xavier Nicolas. "Simplified Modelling of the Infrared Heating Involving the Air Convection Effect before the Injection Stretch Blowing Moulding of PET Preform." Key Engineering Materials 611-612 (May 2014): 844–51. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.844.
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Initial heating conditions and temperature effects (heat transfer with air and mould, self-heating, conduction) have important influence during the ISBM process of PET preforms. The numerical simulation of infrared (IR) heating taking into account the air convection around a PET preform is very time-consuming even for 2D modelling. This work proposes a simplified approach of the coupled heat transfers (conduction, convection and radiation) in the ISBM process based on the results of a complete IR heating simulation of PET sheet using ANSYS/Fluent. First, the simplified approach is validated by comparing the experimental temperature distribution of a PET sheet obtained from an IR camera with the numerical results of the simplified simulation. Second, we focus on the more complex problem of the rotating PET preform heated by IR lamps. This problem cannot be modeled in 2D and the complete 3D approach is out of calculation possibilities actually. In our approach, the IR heating flux coming from IR lamps is calculated using radiative laws adapted to the test geometry. Finally, the simplified approach used on the 2D plane sheet case to model the air convection is applied to the heat transfer between the cylindrical preform and ambient air using a simple model in Comsol where only the preform is meshed. In this case, the effect of the rotation of the preform is taken into account in the radiation flux by a periodic time function. The convection effect is modeled through the thermal boundary conditions at the preform surface using the heat transfer coefficients exported from the simulations of the IR heating of a PET sheet with ANSYS/Fluent. The temperature distribution on the outer surface of the preform is compared to the thermal imaging for validation.
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Mathieu, A., I. Tkachenko, JM Jouvard, and I. Tomashchuk. "Tandem laser-gas metal arc welding joining of 20 mm thick super duplex stainless steel: An experimental and numerical study." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 5 (February 10, 2020): 697–710. http://dx.doi.org/10.1177/1464420720904113.
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The present work covers the topic of strains and stresses prediction in case of welded steel structures. Steel sheets of 20 mm thickness made in UR™2507Cu are welded using a laser and gas metal arc welding processes combination. The focused laser beam leads the arc in a Y-shape chamfer geometry. Both sources are 20 mm apart from each other in order to avoid any synergic effect with each other. In order to predict residual strain, a 3D unsteady numerical simulation has been developed in COMSOL finite element software. A volume heat source has been identified based on the temperature measurements made by 10 K-type thermocouples, implanted inside the workpiece. The 50 mm deep holes are drilled in the workpiece using dye-sinking Electrical Discharge Machining (EDM) machine. Before the implantation in the hole, each thermocouple is surrounded by Inconel sheathing. Hot junctions of the thermocouples are positioned in a way to feel two advancing molten pools. The equivalent heat source is composed of three sources. First one is a Goldak source that represents the molten pool induced by gas metal arc welding. The second one is a cylinder with an elliptic cross-section that represents the focused laser beam penetrating into the workpiece. The third one is a surface Gaussian source that represents energy radiated by arc and blocked by workpiece surface. Concerning mechanical simulation, an elasto-plastic behavior with isotropic hardening is implemented. A weak coupling is established between equations governing heat transfer and mechanics thanks to the temperature dependent coefficient of linear expansion. This numerical simulation made with some simplifying assumptions predicts an angular distortion and a longitudinal shrinkage of the welded structure. The numerical results are consistent with the displacements measured by digital image correlation method.
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Stupnytskyi, R. M., and V. R. Yarychkivskyi. "DIGITAL EXAMINATION METHODS OF ANATOMICAL ELEMENTS OF MASTICATORY SYSTEM AND BASIC OCCLUSION RELATIONSHIPS." Ukrainian Dental Almanac, no. 4 (December 12, 2018): 32–37. http://dx.doi.org/10.31718/2409-0255.4.2018.06.
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In the modern world, dentistry has achieved a significant possibilities in aesthetic and functional restoration of teeth and dental arches thanks to modern computer technologies. Every day, the latest developments in the dental industry, such as CAD-CAM systems, clinical and laboratory scanners, 3D printers, microscopes, become indispensable attributes of dental institutions. Modern equipment expands the capabilities of dentists in the diagnosis of pathologies of the masticatory system, greatly facilitates the choice of an optimal plan of prosthetic treatment and allows to have a good quality of rehabilitation of patients. An individual place in the concept of treatment relates to variety of software that allows to make a treatment plan and predict its results.
Objective. To create a virtual model of the tooth with periodontal tissues and determine the theoretical aspects, conditions and parameters of its application in examination stresses and deformations that arise in different occlusion relationships.
Methods and materials. 3D modeling is a method of creating various forms and complexity of three-dimensional computer models of real or fantastic objects of the world with the use of various techniques and mechanisms.
Autodesk 3ds MAX (3D Studio MAX) and a polygonal modeling method were used to create 3D models. Mathematical simulation (mathematical modeling) is a method of studying processes or phenomena by creating their mathematical models and studying these models. The method is based on the identity of the form of equations and the uniqueness of the relations between the variables in the equations of the original and the model, that is, their analogy.
Mathematical modeling allows you to replace real objects with its virtual model and then study the last one. As with any simulation, the mathematical model is designed taking into account the physical characteristics of the original object.
Mathematical modeling is carried out in Comsol Multiphysics 4.2a software program ("Comsol AB" (Sweden).
For creation of the three-dimensional model, we chose the frontal area of the upper jaw. The model was created by the polygonal modeling method, taking into account the anatomical parameters of natural teeth and periodontal tissues (Autodesk 3Ds Max software). The size of the teeth, the thickness and shape of the bone tissue contours, the magnitude of the deflection of the tooth axis and the alveolar appendix and the thickness of the mucosa were modeled in accordance to the average parameters.
The created models of anatomical elements were later integrated into the program for computer mathematical modeling. During the study we used the finite element method and entered the following values: Young's modulus, Poisson's coefficient and body density.
Characteristics of the materials for calculating the stress-strain state were absolutely identical to the tissues of the tooth and bone. Each model applied forces in different planes according to occlusal movements: in sagittal plane - forward, force 100 N; in horizontal - transversal movements, force 120N; in the vertical - the force is 400 N. The calculation of the magnitude of force was carried out according to the average statistics of the cross-sectional area of masticatory muscles involved in the movements of the mandible. We also note that these values are critical and maximally possible.
Conclusion: The construction of three-dimensional models of teeth and tissues of periodontium helps to understand in detail the essence of processes occurring in the masticatory system during its functioning, to measure stresses, strains and deformations during occlusion relationships. Analysis of the data obtained with the help of mathematical modeling improves the capabilities of dentists at different stages of functional rehabilitation of patients, simplifies the choice of orthopedic design and has a significant predictive value.
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Ilyin, Alexander, Igor Plokhov, Igor Savraev, and Oksana Kozyreva. "Modeling of time dependent thermal process in sliding electrical microcontact." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 3 (June 16, 2015): 109. http://dx.doi.org/10.17770/etr2015vol3.194.
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<p class="R-AbstractKeywords"><span lang="EN-US">Temperature has great influence on mechanical, electrical and chemical processes that occur in transition layer of sliding contact. The aim of the research is creating a three-dimensional finite-element model for calculating time dependent thermal process in sliding electrical microcontact.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The article starts with the description of the contact element representing a discrete microcontact and physics in it. Then the authors suggest use modern simulation software COMSOL Multyphisics for modeling.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The developed 3D-model uses modules of electric currents, heat transfer in solids, and electromagnetic heat source for computing. For each module the assumptions, the initial and boundary conditions are made. </span></p><p class="R-AbstractKeywords"><span lang="EN-US">The outcomes of modeling are the transient processes of average overheat in the elements of contact-details surface layers. The transient processes depend on geometric size of the microcontact (size of contact element, height of surface elements, thickness of oxide films, and overlap), contact-details physical properties (density, electrical conductance, thermal conductivity, and heat capacity), external influences (electrical current and friction heat), and temperatures of the neighbor elements.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The results of the research will be used in the numerical simulation model of sliding electrical contact. </span></p>
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Esman, A. K., V. K. Kuleshov, V. A. Potachits, and G. L. Zykov. "Simulation of Tandem Thin-Film Solar Cell on the Basis of CuInSe2." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 61, no. 5 (October 4, 2018): 385–95. http://dx.doi.org/10.21122/1029-7448-2018-61-5-385-395.
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CuInSe2 thin-film solar cells are promising materials for photovoltaic devices. One of the main tasks of researchers is to find ways to increase the solar cells efficiency. In this paper we propose an original structure of a thin-film solar cell based on a tandem connection of a photoelectric converter and a thermoelectric layer based on CuInSe2. The photoelectric converter consists of CuInSe2 and CdS layers. A 3D model of the proposed thin-film solar cell was implemented in the COMSOL Multiphysics environment with using the Heat Transfer module. The simulation was carried out taking into account the diurnal and seasonal variations of both the ambient temperature and the power density of the AM1.5 solar spectrum for the geographical coordinates of Minsk. The solar radiation power density of about 500 kW/m2 can be achieved by using concentrators. The temperature pattern and temperature gradients are calculated in each layer of the solar cell without and with the temperature stabilization of the substrate back side as well as without and with the thermal insulation of the substrate ends. Graphs of the temperature gradients of the thermoelectric layer and the temperature variations of the photoelectric converter of the solar cell are given. As a result of the simulation, it is shown how the uneven heating of both the surface of a thin-film solar cell and its layers occur under conditions of diurnal and seasonal variations of both the ambient temperature and the solar radiation power density. Under concentrated solar radiation exposure, the photoelectric converter surface can be heated up to 700 °C without temperature stabilization of the solar cell substrate. The operating temperature of the photoelectric converter was maintained at no more than 2.35 °C in January and at no more than 14.23 °C in July due to the temperature stabilization of the substrate back side of the proposed device. This made it possible to achieve an increase in the output power of the solar cell both by summing the photoand thermoelectric output voltages and by the concentration of solar radiation.