932 resultados para ES-SAGD. Heavy oil. Recovery factor. Reservoir modeling and simulation
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In all segments, the companies are looking for the highest productivity with the lowest possible cost, and in the construction industry, the thinking is the same. Over time, techniques that generate more productivity supplanted previous techniques; an example is the CAD technology that replaced free drawings in projects execution. However, the Computer Aided Design (CAD) technology does not deal with certain factors that permeate the entire project. It is required the use of other techniques to supply this need in traditional projects. For example, a software for schedule management, another for assets management and a person who makes calculations for estimates and budgets. The BIM (Building Information Modeling) technology aims to integrate all this information, facilitating the communication among members of a work team and reducing the time required to carry out the project. This work is a applied research, a descriptive research, carried out through modeling and simulation, processes inherent in the use of BIM, a survey was also used only to contextualization. BIM was used for a soccer stadium roof project, in order to verify the feasibility of such use through the analysis of: BIM tools, difficulties encountered and implications of BIM use, and comparison of traditional methods and the use of BIM. To aid the contextualization, a survey was conducted to verify the use of BIM in medium and small companies
Resumo:
In all segments, the companies are looking for the highest productivity with the lowest possible cost, and in the construction industry, the thinking is the same. Over time, techniques that generate more productivity supplanted previous techniques; an example is the CAD technology that replaced free drawings in projects execution. However, the Computer Aided Design (CAD) technology does not deal with certain factors that permeate the entire project. It is required the use of other techniques to supply this need in traditional projects. For example, a software for schedule management, another for assets management and a person who makes calculations for estimates and budgets. The BIM (Building Information Modeling) technology aims to integrate all this information, facilitating the communication among members of a work team and reducing the time required to carry out the project. This work is a applied research, a descriptive research, carried out through modeling and simulation, processes inherent in the use of BIM, a survey was also used only to contextualization. BIM was used for a soccer stadium roof project, in order to verify the feasibility of such use through the analysis of: BIM tools, difficulties encountered and implications of BIM use, and comparison of traditional methods and the use of BIM. To aid the contextualization, a survey was conducted to verify the use of BIM in medium and small companies
Resumo:
Solar reactors can be attractive in photodegradation processes due to lower electrical energy demand. The performance of a solar reactor for two flow configurations, i.e., plug flow and mixed flow, is compared based on experimental results with a pilot-scale solar reactor. Aqueous solutions of phenol were used as a model for industrial wastewater containing organic contaminants. Batch experiments were carried out under clear sky, resulting in removal rates in the range of 96100?%. The dissolved organic carbon removal rate was simulated by an empirical model based on neural networks, which was adjusted to the experimental data, resulting in a correlation coefficient of 0.9856. This approach enabled to estimate effects of process variables which could not be evaluated from the experiments. Simulations with different reactor configurations indicated relevant aspects for the design of solar reactors.
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This thesis deals with two important research aspects concerning radio frequency (RF) microresonators and switches. First, a new approach for compact modeling and simulation of these devices is presented. Then, a combined process flow for their simultaneous fabrication on a SOI substrate is proposed. Compact models for microresonators and switches are extracted by applying mathematical model order reduction (MOR) to the devices finite element (FE) description in ANSYS c° . The behaviour of these devices includes forms of nonlinearities. However, an approximation in the creation of the FE model is introduced, which enables the use of linear model order reduction. Microresonators are modeled with the introduction of transducer elements, which allow for direct coupling of the electrical and mechanical domain. The coupled system element matrices are linearized around an operating point and reduced. The resulting macromodel is valid for small signal analysis around the bias point, such as harmonic pre-stressed analysis. This is extremely useful for characterizing the frequency response of resonators. Compact modelling of switches preserves the nonlinearity of the device behaviour. Nonlinear reduced order models are obtained by reducing the number of nonlinearities in the system and handling them as input to the system. In this way, the system can be reduced using linear MOR techniques and nonlinearities are introduced directly in the reduced order model. The reduction of the number of system nonlinearities implies the approximation of all distributed forces in the model with lumped forces. Both for microresonators and switches, a procedure for matrices extraction has been developed so that reduced order models include the effects of electrical and mechanical pre-stress. The extraction process is fast and can be done automatically from ANSYS binary files. The method has been applied for the simulation of several devices both at devices and circuit level. Simulation results have been compared with full model simulations, and, when available, experimental data. Reduced order models have proven to conserve the accuracy of finite element method and to give a good description of the overall device behaviour, despite the introduced approximations. In addition, simulation is very fast, both at device and circuit level. A combined process-flow for the integrated fabrication of microresonators and switches has been defined. For this purpose, two processes that are optimized for the independent fabrication of these devices are merged. The major advantage of this process is the possibility to create on-chip circuit blocks that include both microresonators and switches. An application is, for example, aswitched filter bank for wireless transceiver. The process for microresonators fabrication is characterized by the use of silicon on insulator (SOI) wafers and on a deep reactive ion etching (DRIE) step for the creation of the vibrating structures in single-crystal silicon and the use of a sacrificial oxide layer for the definition of resonator to electrode distance. The fabrication of switches is characterized by the use of two different conductive layers for the definition of the actuation electrodes and by the use of a photoresist as a sacrificial layer for the creation of the suspended structure. Both processes have a gold electroplating step, for the creation of the resonators electrodes, transmission lines and suspended structures. The combined process flow is designed such that it conserves the basic properties of the original processes. Neither the performance of the resonators nor the performance of the switches results affected by the simultaneous fabrication. Moreover, common fabrication steps are shared, which allows for cheaper and faster fabrication.
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The determination of skeletal loading conditions in vivo and their relationship to the health of bone tissues, remain an open question. Computational modeling of the musculoskeletal system is the only practicable method providing a valuable approach to muscle and joint loading analyses, although crucial shortcomings limit the translation process of computational methods into the orthopedic and neurological practice. A growing attention focused on subject-specific modeling, particularly when pathological musculoskeletal conditions need to be studied. Nevertheless, subject-specific data cannot be always collected in the research and clinical practice, and there is a lack of efficient methods and frameworks for building models and incorporating them in simulations of motion. The overall aim of the present PhD thesis was to introduce improvements to the state-of-the-art musculoskeletal modeling for the prediction of physiological muscle and joint loads during motion. A threefold goal was articulated as follows: (i) develop state-of-the art subject-specific models and analyze skeletal load predictions; (ii) analyze the sensitivity of model predictions to relevant musculotendon model parameters and kinematic uncertainties; (iii) design an efficient software framework simplifying the effort-intensive phases of subject-specific modeling pre-processing. The first goal underlined the relevance of subject-specific musculoskeletal modeling to determine physiological skeletal loads during gait, corroborating the choice of full subject-specific modeling for the analyses of pathological conditions. The second goal characterized the sensitivity of skeletal load predictions to major musculotendon parameters and kinematic uncertainties, and robust probabilistic methods were applied for methodological and clinical purposes. The last goal created an efficient software framework for subject-specific modeling and simulation, which is practical, user friendly and effort effective. Future research development aims at the implementation of more accurate models describing lower-limb joint mechanics and musculotendon paths, and the assessment of an overall scenario of the crucial model parameters affecting the skeletal load predictions through probabilistic modeling.
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CdTe and Cu(In,Ga)Se2 (CIGS) thin film solar cells are fabricated, electrically characterized and modelled in this thesis. We start from the fabrication of CdTe thin film devices where the R.F. magnetron sputtering system is used to deposit the CdS/CdTe based solar cells. The chlorine post-growth treatment is modified in order to uniformly cover the cell surface and reduce the probability of pinholes and shunting pathways creation which, in turn, reduces the series resistance. The deionized water etching is proposed, for the first time, as the simplest solution to optimize the effect of shunt resistance, stability and metal-semiconductor inter-diffusion at the back contact. In continue, oxygen incorporation is proposed while CdTe layer deposition. This technique has been rarely examined through R.F sputtering deposition of such devices. The above experiments are characterized electrically and optically by current-voltage characterization, scanning electron microscopy, x-ray diffraction and optical spectroscopy. Furthermore, for the first time, the degradation rate of CdTe devices over time is numerically simulated through AMPS and SCAPS simulators. It is proposed that the instability of electrical parameters is coupled with the material properties and external stresses (bias, temperature and illumination). Then, CIGS materials are simulated and characterized by several techniques such as surface photovoltage spectroscopy is used (as a novel idea) to extract the band gap of graded band gap CIGS layers, surface or bulk defect states. The surface roughness is scanned by atomic force microscopy on nanometre scale to obtain the surface topography of the film. The modified equivalent circuits are proposed and the band gap graded profiles are simulated by AMPS simulator and several graded profiles are examined in order to optimize their thickness, grading strength and electrical parameters. Furthermore, the transport mechanisms and Auger generation phenomenon are modelled in CIGS devices.
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This thesis develops an effective modeling and simulation procedure for a specific thermal energy storage system commonly used and recommended for various applications (such as an auxiliary energy storage system for solar heating based Rankine cycle power plant). This thermal energy storage system transfers heat from a hot fluid (termed as heat transfer fluid - HTF) flowing in a tube to the surrounding phase change material (PCM). Through unsteady melting or freezing process, the PCM absorbs or releases thermal energy in the form of latent heat. Both scientific and engineering information is obtained by the proposed first-principle based modeling and simulation procedure. On the scientific side, the approach accurately tracks the moving melt-front (modeled as a sharp liquid-solid interface) and provides all necessary information about the time-varying heat-flow rates, temperature profiles, stored thermal energy, etc. On the engineering side, the proposed approach is unique in its ability to accurately solve – both individually and collectively – all the conjugate unsteady heat transfer problems for each of the components of the thermal storage system. This yields critical system level information on the various time-varying effectiveness and efficiency parameters for the thermal storage system.
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Fuel-lean combustion and exhaust gas recirculation (EGR) in spark ignition engines improve engine efficiency and reduce emission. However, flame initiation becomes more difficult in lean and dilute fuel-air mixture with traditional spark discharge. This research proposal will first provide an intensive review on topics related to spark ignition including properties of electrical discharge, flame kernel behavior and spark ignition modeling and simulation. Focus will be laid on electrical discharge pattern effect as it is showing prospect in extending ignition limits in SI engines. An experimental setup has been built with an optically accessible constant volume combustion vessel. Multiple imaging techniques as well as spectroscopy will be applied. By varying spark discharge patterns, preliminary test results are available on consequent flame kernel development. In addition to experimental investigation of spark plasma and flame kernel development, spark ignition modeling with detailed description of plasma channel is also proposed for this study.
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This report presents a study on the problem of spacecraft attitude control using magnetic actuators. Several existing approaches are reviewed and one control strategy is implemented and simulated. A time-varying feedback control law achieving inertial pointing for magnetically actuated spacecraft is implemented. The report explains the modeling of the spacecraft rigid body dynamics, kinematics and attitude control in detail. Besides the fact that control laws have been established for stabilization around local equilibrium, this report presents the results of a control law that yields a generic, global solution for attitude stabilization of a magnetically actuated spacecraft. The report also involves the use MATLAB as a tool for both modeling and simulation of the spacecraft and controller. In conclusion, the simulation outlines the performance of the controller in independently stabilizing the spacecraft in three mutually perpendicular directions.
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This work represents the proceedings of the fifteenth symposium which convened at Colorado State University on May 24, 1985. The two day meeting was scheduled one month later than usual, i.e., after the spring semester, so that travelers from the Midwest (Iowa State University, Kansas State University and University of Missouri) could enjoy the unique mountain setting provided at Pingree Park. The background of the photograph on the cover depicts the beauty of the area. ContentsGreg Sinton and S.M. Leo, KSU. Models for the Biodegration of 2.4-D and Related Xenobiotic Compounds. V. Bringi, CSU. Intrinsic Kinetics from a Novel Immobilized Cell CSTR. Steve Birdsell, CU. Novel Microbial Separation Techniques. Mark Smith, MU. Kinetic Characterization of Growth of E. coli on Glucose. Michael M. Meagher, ISU. Kinetic Parameters of Di- and Trisaccharaide Hydrolysis by Glucoamylase II. G.T. Jones and A.K. Ghosh Hajra, KSU. Modeling and Simulation of Legume Modules with Reactive Cores and Inert Shells. S.A. Patel and C.H. Lee, KSU. Energetic Analysis and Liquid Circulation in an Airlift Fermenter. Rod R. Fisher, ISU. The Effects of Mixing during Acid Addition of Fractionally Precipitated Protein. Mark M. Paige, CSU. Fed-batch Fermentations of Clostridium acetobutylicum. Michael K. Dowd, ISU. A Nonequilibirium Thermodynamic Description of the Variation of Contractile Velocity and Energy Use in Muscle. David D. Drury, CSU. Analysis of Hollow Fiber Bioreactor Performance for MAmmalian Cells by On-Line MMR. H.Y. Lee, KSU. Process Analysis of Photosynthetic Continuous Culture Systems. C.J. Wang, MU. Kinetic Consideration in Fermentation of Cheese Whey to Ethanol.
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This volume represents the proceedings of the Sixteenth Annual Biochemical Engineering Symposium held at Kansas State University on April 26, 1986. Some of the papers describe the progress of ongoing projects, and others contain the results of completed projects. Only brief summaries are given of many of the papers that will be published in full elsewhere. ContentsEnd-Product Inhibition of the Acetone-Butanol Fermentation—Bob Kuhn, Colorado State University Effect of Multiple Substrates in Ethanal Fermentations from Cheese Whey—C.J. Wang, University of Missouri Extraction and Fermentation of Ensiled Sweet Sorghum—Karl Noah, Colorado State University Removal of Nucleic Acids from Bakers' Yeast—Richard M. Cordes, Iowa State University Modeling the Effects of Plasmid Replication and Product Repression on the Growth Rate of Recombinant Bacteria—William E. Bentley, University of Colorado Indirect Estimates of Cell Concentrations in Mass Cultivation of Bacterial Cells—Andrew Fisher, University of Missouri A Mathematical Model for Liquid Recirculation in Airlift Columns—C.H.Lee, Kansas State University Characterization of Imperfect Mixing of Batch Reactors by Two Compartment Model—Peter Sohn, University of Missouri First Order Breakage Model for the Degradation of Pullalan in the Batch Fermentor—Stephen A. Milligan, Kansas State University Synthesis and Nuclear Magnetic Resonance of 13C-Labeled Amylopectin and Maltooligosaccharides—Bernard Y. Tao, Iowa State University Preparation of Fungal Starter Culture in Gas Fluidized Bed Reactor—Pal Mihaltz, Colorado State University Yeast Flocculation and Sedimentation—David Szlag, University of Colorado Protein Enrichment of Extrusion Cooked Corn by Solid Substrate Fermentation—Lucas Alvarez-Martinez, Colorado State University Optimum Design of a Hollow Fiber Mammalian Cell Reactor—Thomas Chresand, Colorado State University Gas Chromatography and Nuclear Magnetic Resonance of Trifluoroacetylated Carbohydrates—Steven T. Summerfelt, Iowa State University Kinetic and Bioenergetic Considerations for Modeling Photosynthetic Microbial P~ocesses in Producing Biomass and Treating Wastewater—H. Y. Lee, Kansas State University Mathematical Modeling and Simulation of Bicarbonate-Limited Photsynthetic Growth in Continuous Culture—Craig Curless, Kansas State University Data Acquisition and Control of a Rotary Drum Solid State Fermentor—Mnasria A. Habib, Colorado State University Biodegradation of 2,4-Dichlorophenoxyacetic Acid (2,4-D)—Greg Sinton, Kansas State University
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Esse trabalho constitui o desenvolvimento da modelagem térmica e simulação por métodos numéricos de dois componentes fundamentais do ciclo de refrigeração por absorção de calor com o par amônia/água: o absorvedor e o gerador. A função do absorvedor é produzir mistura líquida com alta fração mássica de amônia a partir de mistura líquida com baixa fração mássica de amônia e mistura vapor mediante retirada de calor. A função do gerador é produzir mistura líquido/vapor a partir de mistura líquida mediante o fornecimento de calor. É proposto o uso da tecnologia de filmes descendentes sobre placas inclinadas e o método de diferenças finitas para dividir o comprimento da placa em volumes de controle discretos e realizar os balanços de massa, espécie de amônia e energia juntamente com as equações de transferência de calor e massa para o filme descendente. O objetivo desse trabalho é obter um modelo matemático simplificado para ser utilizado em controle e otimização. Esse modelo foi utilizado para calcular as trocas de calor e massa no absorvedor e gerador para diversas condições a partir de dados operacionais, tais como: dimensões desses componentes, ângulo de inclinação da placa, temperatura de superfície e condições de entrada da fase líquida e vapor. Esses resultados foram utilizados para estabelecer relações de causa e efeito entre as variáveis e parâmetros do problema. Os resultados mostraram que o ângulo de inclinação da placa ótimo tanto para o absorvedor como para o gerador é a posição vertical, ou 90°. A posição vertical proporciona o menor comprimento de equilíbrio (0,85 m para o absorvedor e 1,27 m para o gerador com as condições testadas) e se mostrou estável, pois até 75° não foram verificadas variações no funcionamento do absorvedor e gerador. Dentre as condições testadas para uma placa de 0,5 m verificou-se que as maiores efetividades térmicas no absorvedor e gerador foram respectivamente 0,9 e 0,7 e as maiores efetividades mássicas no absorvedor e gerador foram respectivamente 0,6 e 0,5. É esperado que os dados obtidos sejam utilizados em trabalhos futuros para a construção de um protótipo laboratorial e na validação do modelo.
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Mudança climática é um processo global, real e inequívoco. Para sua mitigação, a substituição de combustíveis fósseis por energias renováveis está sendo cada vez mais empregada. Devido à rápida velocidade de crescimento das microalgas, seu cultivo é visto como uma das alternativas mais promissoras para a produção de biocombustíveis. No presente trabalho, foi elaborado um modelo matemático fenomenológico que descreve o crescimento da microalga Chlorella vulgaris. Este modelo foi validado através de experimentos realizados em um reator piloto com capacidade de 1000 L tipo \"open pond\" (reator de raias) aberto ao ambiente, em condições não-axênicas. A variação de concentração devida à evaporação e/ou adição de água foi levada em conta no modelo. O modelo matemático desenvolvido, contendo dois parâmetros ajustáveis, descreve a variação da concentração de biomassa em função do tempo sob condições variáveis de luminosidade e temperatura. Os parâmetros ajustáveis são q (constante para conversão de intensidade luminosa em crescimento fotossintético, em klux-1 min-1) e Imax (limite máximo de intensidade luminosa, em klux). Previamente ao projeto do reator, foram realizados experimentos em reator de laboratório (utilizando a metodologia Taguchi) com o objetivo de determinar quais os fatores mais críticos para o crescimento da espécie de microalga selecionada e que, por isso, deveriam ser controlados com maior precisão. Além disso, foi analisada teoricamente a relevância da consideração do transporte de massa de CO2 no processo. Como este transporte é muito mais lento, a resistência controladora do processo é o crescimento fotossintético. Após a construção do reator piloto, foram realizados dois experimentos preliminares (os quais serviram para aperfeiçoar o aparato e o procedimento experimental) e três experimentos definitivos, registrando-se dados ambientais (temperatura, intensidade luminosa e pH) e de concentração ao longo do tempo. Utilizando os dados de temperatura e luminosidade em função do tempo como entrada, os parâmetros q e Imax otimizados foram ajustados às curvas de concentração versus tempo de cada experimento. Para tal foram desenvolvidos programas de integração de equações diferenciais e de otimização escritos em ambiente Scilab®. Verificou-se que, apesar da variabilidade devida às condições ambientais dos experimentos, obteve-se boa aderência dos dados simulados aos experimentais. Uma análise estatística dos parâmetros q e Imax calculados em cada experimento forneceu coeficientes de variação para estes parâmetros de 17 % e 5 %, respectivamente. Concluiu-se, portanto, que o modelo matemático desenvolvido neste trabalho pode ser empregado para prever o desempenho de um reator de raias em condições ambientais variáveis, bastando para isto o ajuste de dois parâmetros.
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O propósito deste trabalho foi o desenvolvimento de um procedimento simulador de processo reproduzindo a etapa de destilação extrativa de uma unidade de extração de butadieno a partir de uma corrente de hidrocarbonetos na faixa de quatro átomos de carbono, através da adição do solvente n-metil-2- pirrolidona (NMP). Os resultados obtidos foram comparados e validados com dados de processo obtidos por uma unidade industrial de extração de butadieno. O aprofundamento nos conceitos do processo de separação através de uma ferramenta em simulador de processo capaz de predizer condições de operação permitiu avaliações de aumento de capacidade. A capacidade dos elementos internos dos equipamentos envolvidos na separação pode ser avaliada e a identificação do ponto inicial de engargalamento da unidade foi possível. O procedimento proposto também permite reduzir incertezas para identificação de novos pontos de engargalamento a partir de uma nova configuração dos elementos internos identificados como ineficientes com a elevação de carga processada.