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Simulation Software (simulation + software)
Selected AbstractsON THE GEOCHRONOLOGICAL METHOD VERSUS FLOW SIMULATION SOFTWARE APPLICATION FOR LAHAR RISK MAPPING: A CASE STUDY OF POPOCATÉPETL VOLCANO, MEXICOGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 3 2010ESPERANZA MUÑOZ-SALINAS ABSTRACT. Lahars are hazardous events that can cause serious damage to people who live close to volcanic areas; several were registered at different times in the last century, such as at Mt St Helens (USA) in 1980, Nevado del Ruiz (Colombia) in 1985 and Mt Pinatubo (Philippines) in 1990. Risk maps are currently used by decision-makers to help them plan to mitigate the hazard-risk of lahars. Risk maps are acquired based on a series of tenets that take into account the distribution and chronology of past lahar deposits, and basically two approaches have been used: (1) The use of Flow Simulation Software (FSS), which simulates flows along channels in a Digital Elevation Model and (2) The Geochronological Method (GM), in which the mapping is based on the evaluation of lahar magnitude and frequency. This study addresses the production of a lahar risk map using the two approaches (FSS and GM) for a study area located at Popocatépetl volcano , Central Mexico. Santiago Xalitzintla, a town located on the northern flank of Popocatépetl volcano, where volcanic activity in recent centuries has triggered numerous lahars that have endangered local inhabitants, has been used for the case study. Results from FSS did not provide satisfactory findings because they were not consistent with lahar sediment observations made during fieldwork. By contrast, the GM produced results consistent with these observations, and therefore we use them to assess the hazard and produce the risk map for the study area. [source] A novel virtually centered broad wall longitudinal slot for antenna applicationINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 3 2010A. Anand Abstract A virtually centered broad-wall longitudinal slot antenna have been designed and studied using commercial Electromagnetic Simulation Software (CST Microwave Studio). The result obtained for the S21 of such an antenna has been compared with the measured data to find the accuracy of the software. Also the results obtained for the slot have been compared with the more common offset broad-wall longitudinal slot. Different slot characteristics also have been studied by varying different slot parameters. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source] 3D virtual simulator for breast plastic surgeryCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2008Youngjun Kim Abstract We have proposed novel 3D virtual simulation software for breast plastic surgery. Our software comprises two processes: a 3D torso modeling and a virtual simulation of the surgery result. First, image-based modeling is performed in order to obtain a female subject's 3D torso data. Our image-based modeling method utilizes a template model, and this is deformed according to the patient's photographs. For the deformation, we applied procrustes analysis and radial basis functions (RBF). In order to enhance reality, the subject's photographs are mapped onto a mesh. Second, from the modeled subject data, we simulate the subject's virtual appearance after the plastic surgery by morphing the shape of the breasts. We solve the simulation problem by an example-based approach. The subject's virtual shape is obtained from the relations between the pair sets of feature points from previous patients' photographs obtained before and after the surgery. Copyright © 2008 John Wiley & Sons, Ltd. [source] Strategies for fault classification in transmission lines, using learning vector quantization neural networksEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 4 2006A. J. Mazón Abstract This paper analyses different approaches to fault classification, in two-terminal overhead transmission lines, using learning vector quantization (LVQ) neural networks, just verifying its efficiency. The objective is to classify the fault using the fundamental components of 50/60,Hz of fault and pre-fault voltage and current magnitudes. These magnitudes are measured in each phase at the reference end. The accuracy of these methods has been checked using properly validated fault simulation software developed with MATLAB. This software allows simulating faults in any location of the line, to obtain the fault and prefault voltage and current values. With these values, the fault can be classified. Copyright © 2006 John Wiley & Sons, Ltd. [source] Analysis of PV/wind potential in the Canadian residential sector through high-resolution building energy simulationINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2009Ali M. Syed Abstract Rising fuel prices and global warming are two major issues that concern people today. In this paper, the effect that the integration of the hybrid photovoltaic (PV)/wind-turbine generation can have on conservation of energy and reduction of greenhouse gases (GHGs) has been studied. Base-case energy demands were calculated using building energy simulation software and then the residential buildings were equipped with the PV/wind-turbine electricity generation devices. The results show that the integration of those equipments can reduce both cost of fuel and GHG emissions to a fair amount. Copyright © 2008 John Wiley & Sons, Ltd. [source] Influence of Material of Overdenture-Retaining Bar with Vertical Misfit on Three-Dimensional Stress DistributionJOURNAL OF PROSTHODONTICS, Issue 6 2010Ricardo T. Abreu DDS Abstract Purpose: This study evaluated the effects of different bar materials on stress distribution in an overdenture-retaining bar system with a vertical misfit between implant and bar framework. Materials and Methods: A three-dimentional finite element model was created including two titanium implants and a bar framework placed in the anterior part of a severely reabsorbed jaw. The model set was exported to mechanical simulation software, where displacement was applied to simulate the screw torque limited by 100-,m vertical misfit. Four bar materials (gold alloy, silver-palladium alloy, commercially pure titanium, cobalt-chromium alloy) were simulated in the analysis. Data were qualitatively evaluated using Von Mises stress given by the software. Results: The models showed stress concentration in cortical bone corresponding to the cervical part of the implant, and in cancellous bone corresponding to the apical part of the implant; however, in these regions few changes were observed in the levels of stress on the different bar materials analyzed. In the bar framework, screw, and implant, considerable increase in stress was observed when the elastic modulus of the bar material was increased. Conclusions: The different materials of the overdenture-retaining bar did not present considerable influence on the stress levels in the periimplant bone tissue, while the mechanical components of the system were more sensitive to the material stiffness. [source] Robustness of the co-ion transfer ratio in capillary electrophoresisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2009Guillaume L. Erny Abstract In CE, indirect detection mode often exhibits a lower precision than its direct counterpart. Although various explanations have already been advanced, in this work, we aimed to investigate if this is due, in part, to problems of robustness of the co-ion transfer ratio (TR), thus being inherent to this particular detection scheme. This was investigated using simulation software that allows an accurate control of various parameters and validated using acetic acid as a test compound. It was conclusively demonstrated that the TR could vary by more than 6% when the concentration of one of the ions in the BGE was changed by as few as 1%. The presence of a system peak seems to be particularly damaging as it has been shown that the TR of peaks whose mobilities differ by more than 0.5×10,8 m2 V,1 s,1 from one of the system peaks, still have a relatively low robustness. [source] Improved Design of Shearing Sections with New Calculation Models Based on 3D Finite-Element SimulationsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 11 2002Helmut Potente Abstract New models for the Maddock and spiral shearing sections have been developed, employing three-dimensional finite element analysis (3D FEA). These models describe the pressure-throughput and power consumption behavior of the shearing sections for both the extrusion and the injection molding process and have been implemented in the REX 6.0 and PSI 4.0 simulation software. As a consequence it is now possible to describe the process behavior of these shearing sections within just a few seconds with the accuracy of FEA calculations. Actual Maddock shearing section (left) and actual spiral shearing section (right). [source] High gain cavity-backed slot antenna with a windowed metallic superstrateMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008M. A. Hanqing Abstract A novel technique for gain enhancement of cavity-backed slot antenna is developed and discussed. The high gain radiation of the proposed antenna is achieved by a windowed metallic superstrate above the slot. The parametric studies of the proposed structure are provided, the radiation mechanism of the proposed antenna is investigated, and then the design guidelines for this type of radiators are described. The prototype is fabricated and found to have an impedance bandwidth of 12% and a gain of 12.3 dBi at the center frequency of 2.4 GHz. The characteristics of the proposed antenna have been validated by CST simulation software and experiments. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3114,3118, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23880 [source] Design and experimental investigation on novel microstrip band-pass filtersMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2008V. Passi Abstract Two novel fifth order, 2.5-GHz bandpass filters, with 4% bandwidths were designed and fabricated. The filters which are modified versions of the hairpin filter are designed empirically using the optimization feature in microwave simulation software. We found good agreement between the simulated and measured responses of these filters, validating the optimization design methodology. The original hairpin filter has also been fabricated, and it is shown that the novel filters have good performance in comparison. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 655,658, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23152 [source] Application of LQ modelling and optimization in urban traffic controlOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 6 2003Majura F. Selekwa Abstract The increasing congestion on urban streets demands traffic control signal timing to be well co-ordinated and optimized even during the transition between timing patterns used in different periods of time-of-day (TOD). The TOD timing plans, defined by fixed-time co-ordination parameters, need to change from one TOD period to another. The current methods used in transitioning are aimed at achieving quick transition rather than optimizing traffic flow during the transition period. As a result, they generally cause increased vehicle delays during the transition period particularly for vehicles on the minor street, which face lengthened red times. This paper proposes a quadratic optimization method that can be used to reduce disutility measures to motorists during the transition period. The transition is modeled as a linear dynamic process, and the disutility measures are modeled as the sum of squares of the deviations of the co-ordination parameters,that is, cycle length, phase split, and offset,from the optimal values during the transition. A linear quadratic (LQ) optimization technique of optimal control is used to determine the step size and the number of steps necessary to complete the transition with minimum disutility. The proposed transition period optimization method has the advantage that the user need not specify minimum and maximum cycle length to achieve optimization, as is the case with current methods. Simulation results for three co-ordinated intersections showed that the proposed method reduces total vehicle delay when compared to the ,immediate' transition method embedded in CORSIM traffic simulation software. This is due to the fact that vehicles on the minor street approaches get proportional green time without significantly affecting green times on the major street approach green phase. However, the method showed a slight increase in total delay for vehicles on the major street. Copyright © 2003 John Wiley & Sons, Ltd. [source] Effect of variable crucible dropping rate on solid-liquid interface in CdZnTe crystal growthPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2010Chenying Zhou Abstract The Cd0.9Zn0.1Te crystal growth with low pressure and vertical Bridgman method (LPVB) was numerically simulated and analysed by the simulation software of Comsol Multiphysics. In the process of crystal growth, the influence of variable crucible dropping rate on solid-liquid interface was studied in this paper. The variability of crucible dropping rate was achieved by a specifical furnace temperature distribution function, while the selection and analysis of crucible dropping rate was obtained by the combination of orthogonal experimental design method and regression analysis method. In this paper, the value of relative crystal growth rate was defined, and the influence of variable crucible dropping rate on solid-liquid interface was discussed by comparing these values. The simulation results showed that if the crucible dropping rate was 3.5 mm/h (,1) in the first stage and 0.6 mm/h (,2) in the second stage, and the distance (d) between the bottom of crucible and the position of melting point in tempreture field was 0.02 m at the time of dropping rate change, the solid-liquid interface was appreciably convex after 211 hours' growth, and the relative crystal growth rate was 0.45%, which made the solid-liquid interface smooth and kept the crystal grow up spontaneously. [source] Design of optimal extrusion die for a range of different materialsPOLYMER ENGINEERING & SCIENCE, Issue 3 2009Nadhir Lebaal THE coat-hanger melt distributor is a device commonly used in the wire coating process. Its task is to distribute the melt around the conductor uniformly. It is quite common that materials and flow rates differ from what had been specified during the design procedure. This may lead to bad performance with materials of very different rheological properties from the design material. In this article, we present an optimal design approach to avoid this loss of performances. This approach involves coupling a three-dimensional finite element simulation software with an optimization strategy based on a response surface method. The objective is to determine a coat-hanger melt distributor geometry that ensures a homogeneous exit velocity distribution that will best accommodate for a different range of materials. A coat-hanger melt distributor with a manifold of constant width is designed, and a set of flow distribution measurements is established for two different materials. The results of numerical simulation are then validated by comparison with experimental measurements. The effect of material change is also investigated. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers [source] | |||||||||||||||||||||||||