Avec l’accroissement considérable de la puissance de calcul, les simulations aux grandes échelles (SGE) sont maintenant utilisées de façon routinière dans de nombreuses applications d’ingénierie. Les modèles de combustion usuels utilisés dans les SGE sont le plus souvent basés sur une hypothèse d’équilibre entre le mouvement des structures turbulentes et le plissement de la surface de la flamme. Ils s’écrivent alors sous forme d’expressions algébriques fonctions de grandeurs connues aux échelles résolues ainsi que de paramètres dont l’ajustement est à la charge de l’utilisateur selon la configuration étudiée et les conditions opératoires. Le modèle dynamique récemment développé ajuste automatiquement au cours du calcul les paramètres de modélisation qui peuvent alors dépendre du temps et de l’espace. Cette thèse présente une étude détaillée d’un modèle dynamique pour la simulation aux grandes échelles de la combustion turbulente prémélangée. L’objectif est de caractériser, explorer les avantages et les inconvénients, appliquer et valider le modèle dynamique dans plusieurs configurations. / Large eddy simulation (LES) is currently applied in a wide range of engineering applications. Classical LES combustion models are based on algebraic expressions and assume equilibrium between turbulence and flame wrinkling which is generally not verified in many circumstances as the flame is laminar at early stages and progressively wrinkled by turbulent motions. In practice, this conceptual drawback has a strong consequence: every computation needs its own set of constants, i.e. any small change in the operating conditions or in the geometry requires an adjustment of model parameters. The dynamic model recently developed adjust automatically the flame wrinkling factor from the knowledge of resolved scales. Widely used to describe the unresolved turbulent transport, the dynamic approach remains underexplored in combustion despite its interesting potential. This thesis presents a detailed study of a dynamic wrinkling factor model for large eddy simulation of turbulent premixed combustion. The goal of this thesis is to characterize, unveil pros and cons, apply and validate the dynamic modeling in different flow configurations.

Este trabalho apresenta a modelagem da parte dinâmica de dois transdutores de pressão tipo piezorresistivo. Geralmente processos de calibração dinâmica usam bancadas sofisticadas, mas neste trabalho procurou-se um processo simples e de baixo custo. A metodologia baseou-se em aumentar lentamente a pressão, fornecida por um sistema hidráulico básico, até que ocorresse a explosão de um diafragma e, com isso, obteve-se um degrau de pressão, supostamente ideal. Considerado como sistemas lineares, com a resposta obtida verificou-se qual a ordem e o tipo de sistema correspondente à resposta do transdutor. Através dos dados experimentais determinou-se os parâmetros dinâmicos do modelo matemático. Foram obtidos modelos matemáticos lineares de segunda ordem de cada transdutor. As respostas dos modelos mostram ter uma concordância satisfatória quando comparadas aos dados experimentais. / This work presents a dynamic modeling method for two hydraulic piezoresistive pressure transducers. Usually the dynamic calibration processes apply sophisticated devices, but in this work a simple and low cost process was searched. The methodology was based on increasing the pressure slowly, supplied by a basic hydraulic system, up to a diaphragm explosion, assumed as an ideal step pressure variation. Considered as linear systems, the responses obtained were verified and compared with a second order linear system. Using the experimental data, the dynamic parameters of the mathematical model were determined for each of the two transducers. The theoretical responses of the models showed to have a satisfactory agreement when compared with the experimental data.

Este trabalho apresenta um modelo matemático linear para um sistema hidráulico proposto para funcionar como um amortecedor para pequenas amplitudes de deslocamento, da ordem de décimos de milímetros. As dimensões para o sistema hidráulico foram adotadas e parâmetros foram determinados. Foram escolhidos dois conjuntos de parâmetros dimensionais e dois valores para o bulk modulus equivalente, o que permitiu fazer o estudo de quatro situações. A verificação das características dinâmicas do sistema foi efetuada utilizando o conceito de função descritiva. Um programa em Matlab/Simulink com um filtro de Fourier foi implementado para obtenção das curvas da resposta em freqüência. A eficiência deste programa computacional foi comprovada através de sua aplicação a sistemas cujas respostas em freqüência são conhecidas. As curvas das respostas em freqüência do sistema hidráulico e do amortecedor ideal foram comparadas. Considerando tolerância de \'+ OU -\' 1 grau para a fase e de \'+ OU -\' 1 db para magnitude, o sistema hidráulico simulado, com bulk modulus equivalente de 100000 psi teve comportamento similar ao amortecedor ideal na faixa de freqüência de 0,1 a 150 rad/seg. No caso do bulk modulus de 30000 psi, a faixa foi estendida, isto é, de 0,1 a 200 rad/seg. / This work presents a linear mathematical model for a proposed hydraulic system intended to work as a damper for small displacement, of the order of decimals of millimeters. The dimensions of the hydraulic system were adopted and parameters were determined. Two sets of the dimensions and two values for the equivalent bulk modulus were chosen and that allowed the study of four situations. The system dynamic properties were verified using the concept of describing function. A Matlab/Simulink program applying the concept of a Fourier filter was carried out in order to obtain the frequency response curves. The efficiency of this program was verified through its application in systems which frequency responses are known. The systems and the ideal damper frequency response curves were compared. Considering tolerance of \'+ OU -\' 1 degree for the phase and \'+ OU -\' 1 db for magnitude, the simulated hydraulic system with an equivalent bulk modulus of 100000 psi showed to be similar to an ideal damper, for the frequency range from 0.1 to 150 rad/sec. For the equivalent bulk modulus of 30000 psi, the frequency range was extended from 0.1 to 200 rad/sec.

Fault diagnosis of sensors, devices, and equipment is an important topic in the nuclear industry for effective and continuous operation of nuclear power plants. All the fault diagnostic approaches depend critically on the sensors that measure important process variables. Whenever a process encounters a fault, the effect of the fault is propagated to some or all the process variables. The ability of the sensor network to detect and isolate failure modes and anomalous conditions is crucial for the effectiveness of a fault detection and isolation (FDI) system. However, the emphasis of most fault diagnostic approaches found in the literature is primarily on the procedures for performing FDI using a given set of sensors. Little attention has been given to actual sensor allocation for achieving the efficient FDI performance. This dissertation presents a graph-based approach that serves as a solution for the optimization of sensor placement to ensure the observability of faults, as well as the fault resolution to a maximum possible extent. This would potentially facilitate an automated sensor allocation procedure. Principal component analysis (PCA), a multivariate data-driven technique, is used to capture the relationships in the data, and to fit a hyper-plane to the data. The fault directions for different fault scenarios are obtained from the prediction errors, and fault isolation is then accomplished using new projections on these fault directions. The effectiveness of the use of an optimal sensor set versus a reduced set for fault detection and isolation is demonstrated using this technique. Among a variety of desalination technologies, the multi-stage flash (MSF) processes contribute substantially to the desalinating capacity in the world. In this dissertation, both steady-state and dynamic simulation models of a MSF desalination plant are developed. The dynamic MSF model is coupled with a previously developed International Reactor Innovative and Secure (IRIS) model in the SIMULINK environment. The developed sensor placement design and fault diagnostic methods are illustrated with application to the coupled nuclear desalination system. The results demonstrate the effectiveness of the newly developed integrated approach to performance monitoring and fault diagnosis with optimized sensor placement for large industrial systems.

During the last decades, batch distillation is preferably used with an increasing demand over continuous one, to separate fine chemicals in chemical and petroleum industries, due to its advantages like, flexibility and high product purity. Consequently, packed distillation columns, with newly generated packing materials, are advantageous compared to plate columns because of their smaller holdups, resistivity to corrosive materials and their higher separation efficiencies. Also, in many industrial applications, mathematical models of distillation systems are frequently used in order to design effective control systems, to train operating personnel and to handle fault diagnostics. Thus, the main objective of this study is to develop a mathematical model for a multicomponent batch distillation column, which is used to separate mixtures at low operating pressures, packed with random packing materials. In multicomponent batch packed distillation, operation with optimum reflux ratio profile is important for efficiency to maximize the amount of the distillate with a specified concentration, for a given time. Therefore, it is also aimed to find the optimum reflux ratio profile for the multicomponent batch packed distillation column. A simulation algorithm is written with the aid of MATLAB and FORTRAN programming languages by taking into account pressure drop and variation of physical properties. The selected incremental bed height, &amp / #916 / z, to be used in the simulation program has an effect on the accuracy of the results. This is analyzed and the optimal incremental height is found to be 3.5 cm for a 1.5m bed height. The change in distillate compositions with a given constant reflux ratio is found to be similar with those of previous studies. The simulation code is also used to obtain responses in distillate compositions for different reflux ratios, condenser holdups and reboiler duties and compared with similar studies found from literature and found to be adequate. Finally, experiments are conducted to verify simulation algorithm by using a lab-scale packed distillation column for the separation of a polar mixture of ethanol and water. It is observed that, there is a good agreement between the experimental and simulation results. After the verification of dynamic model, optimum operation policy to maximize product amount is investigated numerically by using capacity factor approach. The column is operated with and without recycling of the holdups of the slop cut tanks, in order to examine the effect of recycling on capacity factor, CAP. It is observed that, recycling of the molar holdups of the slop cut tanks is resulted in a 28% increase in the separation efficiency.

Economic events of this era reflect the fact that the value of information and technology has surpassed the value of physical production. This motivates countries to focus on increasing the education levels of citizens. However, policy making about education system and its returns requires dynamical analyses in order to be sustainable. The study aims to investigate the dynamic characteristics of a country-wide education system, in particular, that of Turkey. System Dynamics modeling, which is one of the most commonly referred tools for understanding the complex social structures, is used. Our model introduces dynamic relationships among different classes of labor forces with varying education levels, university admissions, research quality, and the investments made in education, research and other sectors. Model experimentation provides new insights into the investment and capacity-related aspects of the education system environment.

A simple anaerobic digestion model has been developed for a continuously-stirred tank reactor (CSTR), which links the specific biogas production rate to the food/microorganism ratio (F/M). The model treats the various microbial populations involved in the sequential biological processes involved in anaerobic digestion as a composite and links the entire biomass specific growth rate directly to the specific biogas production rate. The model was calibrated by determining the specific gas production rate for a range of F/M values using a municipal wastewater seed sludge. The model predictions for steady-state biogas production rates were compared to observed biogas production and volatile solids destruction results from three laboratory-scale anaerobic digesters that were operated at hydraulic retention times of 10, 15, and 20 days. The F/M model results were shown to agree with reactor biogas output for 10, 15, and 20 day hydraulic retention times to within 5.0%, 14.3%, and 9.5%, respectively. A commercial wastewater treatment plant model, BioWin 3, was also used to model anaerobic digestion as a comparison. Agreement for the BioWin 3 model results, as compared to the 10, 15, and 20-day hydraulic retention time reactors, was within 66.2%, 114.1%, and 105.1%, respectively. In all cases the BioWin 3 model over-predicted biogas output as compared to the reactors. A molecular biology method called RT-RiboSyn was developed to measure the specific growth rate of microbial populations. RT-RiboSyn, is an ex situ method that utilizes a reverse transcription and primer extension (RT&PE) method to analyze the rRNA extracted from a time series of samples treated with chloramphenicol. The method measures the rate of ribosome synthesis over time through the increase in precursor 16S rRNA (pre16S rRNA) relative to the mature 16S rRNA (16S rRNA). A single fluorescently labeled primer that targets an interior region of both pre16S and 16S rRNA for a distinct population is used to generate two pools of reverse transcription product. The ratio of pre16S and 16S rRNA is then determined by separating these pools by length using capillary electrophoresis, and measuring the fluorescent intensity of each pool of fragments. Results from three different log growth cultures of Acinetobacter calcoaceticus indicate that RT-RiboSyn, as compared to spectrophotometer readings, was able to predict specific growth rates within -3.1% to 10% and -3.3% to 21.0% when using a primer targeting Eubacteria and Acinetobacter, respectively. The RT-RiboSyn results from a stationary phase culture predicted no growth and possible 16S rRNA degradation. Further work was completed to determine whether the RiboSyn method would successfully measure growth rates of specific microbial populations in environmental samples. The first of these was activated sludge from a high-purity oxygen system in a wastewater treatment facility located in Tampa, Florida. The organism targeted was the Acinetobacter genus, which was shown to be prevalent via fluorescence in situ hybridization results. RT-RiboSyn results indicated that growth was not measureable for the Acinetobacter present in the system; however, since the sludge was taken at the end of the process, Acinetobacter may have been in stationary phase when the samples were collected. Attempts were made to apply the method to methanogens in both pure culture and anaerobic digester sludge samples. An analysis of samples of RNA from Methanosarcina barkeri indicated that the presence of 16S rRNA could be measured; however, capillary electrophoresis instrument limitations prevented the detection of pre16S rRNA fragments. Additional testing of anaerobic digester sludge for both bacterial and Archaeal population was successful for detecting 16S rRNA and possibly precursor 16S rRNA fragments of a variety of lengths. However, specific growth rates could not be determined for the Archaea present in these samples, either due to capillary electrophoresis limitations or very slow growth rates. The results show that the RT-RiboSyn method is applicable to pure cultures; however, a modification of the method is needed to overcome the limitations apparent in populations with low specific growth rates.

With the advent of steerable, ram air parafoil canopies, aerial payload delivery has become a viable alternative for situations involving remote or undeveloped areas, hostile environments, or otherwise inaccessible locations. Autonomously guided systems utilizing such steerable, ram air canopies are typically controlled by symmetric and asymmetric deflection of the canopy trailing edge. Although these systems have demonstrated substantial improvement in landing accuracy over similarly sized unguided systems, their low number of available control channels and limited ability to alter vehicle glide slope during flight makes them highly susceptible to atmospheric gusts and other unknown conditions near the target area. This research aims to improve landing accuracy in such adverse conditions by replacing the standard trailing edge deflection control mechanism in favor of upper surface canopy spoilers. These spoilers operate by opening several spanwise slits in the upper surface of the parafoil canopy thus forming a virtual spoiler from the stream of expelled pressurized air. In particular, estimation of steady-state vehicle flight characteristics in response to different symmetric and asymmetric spoiler openings was determined for two different small-scale test vehicles. Additionally, improvements in autonomous landing accuracy using upper surface spoilers in a combined lateral and longitudinal control scheme was investigated computationally using a high fidelity, 6-DOF dynamic model of the test vehicle and further validated in actual flight experiments with good results. Lastly, a novel in-canopy bleed air actuation system suitable for large-scale parafoil aircraft was designed, fabricated, and flight-tested. The in-canopy system consists of several small, specifically designed wireless winch actuators mounted entirely inside the parafoil canopy. Each in-canopy actuator is capable of opening one or more upper surface canopy spoilers via a unique internal rigging structure. This system demonstrates not only the applicability of bleed air spoiler control for large-scale autonomous parafoil and payload aircraft, but also provides the potential for significant savings in size, weight, and cost of the required actuation hardware for currently fielded systems.

Na atualidade, as atividades humanas têm levado a conversão das áreas de florestas tropicais em ecossistemas agropastoris e urbanos. Neste processo, a floresta contínua é interrompida por estas barreiras antrópicas as quais são capazes de impedir o fluxo gênico, aumentando a taxa de endocruzamento, o que pode acarretar a diminuição da variabilidade genética e a consequente perda da biodiversidade. A Mata Atlântica, alvo deste estudo, perdeu aproximadamente 71% de sua área original, sendo que seus remanescentes apresentam, na sua grande maioria, áreas pequenas e isoladas uma das outras. Neste contexto, o objetivo desta tese foi de avaliar a evolução da fragmentação florestal no município de Caxias do Sul-RS entre 1985 e 2011, calibrar um modelo dinâmico espacial deste processo e simular um cenário futuro para o ano de 2021, buscando verificar se as mudanças ocorridas ao longo deste período refletem em uma modificação na qualidade ambiental destes fragmentos florestais levando em consideração índices de ecologia de paisagem. Para atingir o objetivo proposto, foi utilizado uma série temporal de imagens do satélite Landsat 5, informações pedológicas, do relevo (hipsometria e clinografia) e índices de ecologia de paisagem. Os resultados indicaram um aumento de aproximadamente 203km² das áreas florestais entre os anos de 1985 e 2011, correspondendo a um incremento 36% das Florestas Estacional Decidual e Ombrófila Mista e também de 20% para o cenário simulado (2021). Em contraponto, houve a diminuição das áreas dos campos de nativos na ordem de 33% de 1985 a 2011 e um pequeno incremento de aproximadamente 5 km² para o cenário simulado (2021). Os índices de ecologia de paisagem indicaram uma melhoria na qualidade ambiental no que tange aos fragmentos florestais, uma vez que tamanho médio e a área interior dos fragmentos aumentaram, ocasionando uma maior coesão entre as áreas florestais vizinhas. Estas informações compõem um indicativo de que a regulamentação do manejo das áreas de Mata Atlântica pode ter favorecido a expansão florestal. Os dados gerados poderão ser utilizados como ferramenta balizadora para a proposição de políticas públicas de visam a consonância entre o desenvolvimento socioeconômico e a preservação ambiental. / At present, human activities have led to conversion of tropical forests in agropastoral and urban ecosystems. In this process, the continuous forest is interrupted by these anthropogenic barriers which are able to prevent gene flow, increasing inbreeding rate, which can lead to decreased genetic variability and the resulting loss of biodiversity. The Atlantic Forest, target of this study, lost approximately 71% of its original area, and its remnants have, for the most part, small areas and isolated from each other. In this context, the aim of this study was to assess the evolution of forest fragmentation in the city of Caxias do Sul-RS between 1985 and 2011, calibrate a spatial dynamic model of this process and simulate a scenario for the year 2021, seeking to verify if the changes and expected present and future scenario reflected in a change in environmental quality of these forest fragments considering landscape ecology indices. To achieve this purpose, we used a time series of satellite images Landsat 5, soil information, topographic (hypsometric and slope) and landscape ecology indices. The results showed an increase of approximately 203km² of forest areas between the years 1985 and 2011, corresponding to an increase of around 36% of Seasonally Deciduous Forests and Mixed Ombrophilous and also 20% for the simulated scenario (2021) In contrast, there was the decrease in areas of native grasslands of about 33% from 1985 to 2011 and a small increase of approximately 5 km² to the simulated scenario (2021). The landscape ecology indices indicated improved environmental quality in terms forest fragments, since average size and the inner area of the fragments increased, leading to greater cohesion between neighboring forest areas. This information generates an indication that the management of the Atlantic Forest may have favored forest expansion. The data generated can be used as guiding tool for proposing public policies aimed at the line between socioeconomic development and environmental preservation.

abstract: The semiconductor manufacturing business model provides unique challenges for the design and construction of supporting fabrication facilities. To accommodate the latest semiconductor processes and technologies, manufacturing facilities are constantly re-tooled and upgraded. Common to this sector of construction is the retrofit project environment. This type of construction project introduces a multitude of existing conditions constraints and functions entirely differently than traditional new-build projects. This facility conversion process is further constrained by owner needs for continuous manufacturing operations and a compressed design/construction schedule to meet first-to-market milestones. To better control the variables within this project environment, Building Information Modeling (BIM) workflows are being explored and introduced into this project typology. The construction supply-chain has also increased their focus on offsite construction techniques to prefabricate components in a controlled environment. The goal is to overlap construction timelines and improve the productivity of workers to meet the increasingly demanding schedules and to reduce on-site congestion. Limited studies exist with regards to the manufacturing retrofit construction environment, particularly when focusing on the effectiveness of BIM and prefabrication workflows. This study fills the gap by studying labor time utilization rates for Building Information Modeling workflows for prefabrication of MEP (mechanical/electrical/plumbing) and process piping equipment in a retrofit construction environment. A semiconductor manufacturing facility serves as a case-study for this research in which the current state process for utilizing BIM for prefabrication is mapped and analyzed. Labor time utilization is studied through direct observation in relation to the current state modeling process. Qualitative analysis of workflows and quantitative analysis of labor time utilization rates provide workflow interventions which are implemented and compared against the current state modeling process. This research utilizes a mixed-method approach to explore the hypothesis that reliable/trusted geometry is the most important component for successful implementation of a BIM for prefabrication workflow in a retrofit environment. The end product of this research is the development of a prefaBIM framework for the introduction of a dynamic modeling process for retrofit prefabrication which forms the basis for a model-based delivery system for retrofit prefabrication. / Dissertation/Thesis / Doctoral Dissertation Construction 2016