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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Modelagem e simulação dinâmica de colunas de destilação

Staudt, Paula Bettio January 2007 (has links)
A pesquisa acerca da modelagem de colunas de destilação não é mais uma novidade nos dias de hoje. Os primeiros trabalhos, com metodologias propostas para a solução de sistemas de separação modelados prato a prato, surgiram na década de 30. Porém, só a partir da década de 50, com o advento do computador digital, foram realizados investimentos sólidos no desenvolvimento de novos algoritmos e simuladores. Apesar deste investimento, apenas modelos simplificados eram utilizados devido à baixa capacidade de processamento. A partir da década de 70, os primeiros simuladores comerciais começaram a ser introduzidos na indústria e o desenvolvimento de modelos rigorosos não parou mais. Dentro deste contexto, este trabalho tem como objetivo o desenvolvimento de um modelo rigoroso de coluna de destilação, genérico, dinâmico e de fácil aplicação nos mais variados tipos de estudos, desde simples simulações de operação até otimizações e previsões de comportamentos de parada e partida de plantas. Ou seja, um modelo projetado para situações onde uma representação fiel do comportamento dinâmico é necessária. Os modelos gerados neste estudo foram implementados na linguagem de modelagem do simulador EMSO e fazem parte da biblioteca EML (EMSO Model Library). Esta biblioteca é distribuída no conceito de software livre, disponibilizando todos os modelos via internet e sem custo. Para a validação dos modelos desenvolvidos foram utilizados dois exemplos: uma coluna de destilação reativa com dados provenientes da literatura e uma coluna deisobutanizadora industrial da PETROBRAS com 80 pratos que separa o isobutano de uma mistura de 13 componentes. Este último problema resulta em um sistema com mais de 6300 variáveis, provando que o simulador utilizado é muito eficiente para a resolução de problemas de grande escala. Os resultados da validação foram satisfatórios, assim como o desempenho do simulador EMSO quanto à eficiência computacional e à robustez na solução do problema. / Nowadays, modeling and simulation of distillation columns are not a new research subject anymore. It was around the 1930’s that the first methodologies were proposed to solve staged separation systems. However, it was in 1950’s, with the advent of digital computers that most important investments were made for the development of new algorithms and simulators. In spite of these investments, only very simple models were used due to the low speed of the computers available at that time. In the 1970’s, the industry started to use the first commercial simulators and the development of rigorous models for distillation columns has not stopped since then. Inside this context, the main goal of this work is the development of a rigorous, generic, dynamic and easy-to-use model of distillation column to be applied on diferent targets, from operation simulations to dynamic optimizations and the prediction of the start up and shut down plant behaviour. To do so, the model must represent the dynamic performance of the unit. The models generated were implemented in the EMSO simulator environment with its own modeling language and are part of the EMSO Model Library (EML), which is distributed under the Free Software concept. In order to analyze the model performance, two examples were chosen: a reactive distillation column from the literature and an 80 tray deisobutanizer column from PETROBRAS which separates isobutane of a 13 component mixture. The solution of the last problem generates a 6300 variable system, that is used to confirm the great efficiency of EMSO to solve large scale problems. The validation results have been as satisfactory as the model prediction and the EMSO simulator performance in computational efficiency and robustness.
52

Modelo para negociar as alternativas de gestão de bacias : o caso do Programa Pró-Dilúvio em Porto Alegre, RS

Oliveira, Othon Fialho de January 2006 (has links)
As atividades de gestão ambiental nem sempre têm levado a resultados satisfatórios. Uma das possíveis falhas pode estar ocorrendo por não se dar a devida importância à etapa de estruturação dos problemas, quando os objetivos e meios são adequadamente estabelecidos. Para que estes elementos sejam representativos do contexto decisório, eles devem estar de acordo com os valores dos decisores. A identificação destes valores permite uma modelagem mais fiel do problema que se deseja resolver. Uma vez estruturado o problema, parte-se para o estudo das possíveis alternativas. Como a decisão cabe apenas aos decisores e o papel dos técnicos é assessorá-los nesse processo, é importante que os mesmos possam compreender o papel desempenhado por cada uma das variáveis que julga relevante para descrever o problema. Esta compreensão geralmente não é uma tarefa fácil, visto que os problemas têm um caráter sistêmico, ou seja, os vários elementos envolvidos se relacionam de diversas formas. Assim, o efeito na mudança de apenas uma variável pode repercutir de uma maneira quase imprevisível, o que torna uma análise conjunta de todos os elementos extremamente complexa. Este estudo busca esclarecer a importância da avaliação da dinâmica dos sistemas, incorporando aspectos quantitativos e qualitativos considerados relevantes pelos decisores, para a obtenção de resultados mais satisfatórios nos processos de tomada de decisão, além de propor uma metodologia para melhorar a percepção das alternativas de gestão pelos decisores. A metodologia proposta agrega a identificação das variáveis do problema consideradas como relevantes pelos decisores, utilizando os conceitos de indicadores, modelo pressão-situaçãoresposta e mapas cognitivos, a modelos de simulação dinâmica que permitem o estudo de alternativas através da avaliação da dinâmica do sistema. Esta metodologia foi testada num estudo de caso, o Programa Pró-Dilúvio da Prefeitura de Porto Alegre, que visa promover ações que conduzam à melhoria da qualidade das águas da Bacia do Arroio Dilúvio através da ação conjunta de diversos órgãos municipais. Foi observado que a metodologia proposta de estruturação pode ser bastante útil para definir os elementos descritores do problema, pois facilita a sistematização do procedimento. Em relação à utilização de modelos de simulação dinâmica, constatou-se que os mesmos são úteis na medida em que são aceitos pelos decisores como ferramentas de suporte à decisão. Além disso, a utilização desses modelos em grupos de decisores pode ser bastante útil para facilitar que a negociação atinja soluções de consenso. / The environmental management practices have often led to unsatisfactory results. One possible fault could be happening at the structuring phase, when the basic evaluation elements such as the main objectives and the means to reach them are defined. To be representative for problem modeling, these factors must be according to the decision context to which they belong and to the decision makers’ subjective values. Done with the structuring phase, the potential alternatives are studied. As the decision should be exclusive to the decision makers and the technicians’ role is to facilitate and support this process, then it is important to make them realize the impact of each of those qualitative and quantitative elements in the whole system. This task is even more difficult than it seems, because of the systemic characteristic of the environmental problems. Therefore, the effect of changing just one of these variables could lead to imprecise schemes and thus an analysis considering all the interactions of these variables altogether is very complex. This study attempts to clarify the importance of considering these factors in order to achieve more satisfactory results and to propose a method to increase the decision makers’ perception of how the whole system works and how it affects the potential alternatives. The method binds the identification of the relevant aspects at the decision makers’ point of view (utilizing the concepts of indicators, pressure-state-response model and cognitive maps) with the simulation dynamic models which allow the alternatives’ study throughout the system dynamics assessment. This methodology was tested at the Pró- Dilúvio Program which was launched by the Porto Alegre Town Hall and aggregates many municipal institutions aiming at the revitalization of the Dilúvio Creek Basin by pollution impact mitigation. It was observed that the structuring methodology could be very useful for defining the decision context descriptive elements because it systematizes the proceedings. In terms of utilization of dynamic simulation, it was observed that it could be an alternative to negotiate a compromise solution in a group of decision makers. However, it is important to highlight that these models should only be built if they are to be accepted as a decisionsupporting tool.
53

Desenvolvimento e aplicação de metodologia para estudos de simulação dinâmica na cadeia do minério de ferro. / Development and application methodology for dynamic simulation studies of the iron ore supply chain.

Dennis Travagini Cremonese 07 February 2014 (has links)
Este estudo propõe uma metodologia para a simulação dinâmica da cadeia de produção mineral. A metodologia proposta permite que modelos complexos sejam construídos rapidamente e com precisão, reduzindo os custos de estudos nas fases de projeto e possibilitando reduções mais expressivas nos custos de implantação e operação do empreendimento. A metodologia proposta abrange todas as etapas de estudo desde a formulação do problema a ser analisado até a implementação dos resultados e foi aplicada em um projeto, durante as fases de FEL 2 e 3 (Projeto Conceitual e Básico). O projeto estudado consiste da produção de produtos de minério de ferro de uma empresa de mineração em Corumbá/MS, incluindo lavra, beneficiamento e transporte do minério beneficiado por ferrovia até o porto de Santos/SP. São apresentadas as premissas, dados de entrada e conceitos para criação de um modelo que integre Pátio de Estocagem da Usina de Beneficiamento, Ferrovia e Porto, além dos dados de saídas do modelo necessários para avaliação e suas análises. Com base nos resultados obtidos foram identificados as ações que podem ser tomadas para o aumento da eficiência do trabalho de modelagem. A aplicação da metodologia proposta permitiu comprovar que um modelo integrado de simulação, envolvendo as diferentes atividades da cadeira de produção mineral, oferece uma visão global dos processos envolvidos e facilita a tomada de decisão. / This study proposes a methodology for dynamic simulation of the mineral supply chain. The proposed methodology allows complex models to be built quickly and accurately, reducing the costs of studies in the design phases and enabling more substantial reductions in the costs of implementation and operation of the enterprise. The proposed methodology covers all stages of study since the problem formulation to be analyzed until the results implementation and was applied in a project, during the phases of FEL 2 and 3 (Pre-Feasibility and Feasibility Study). The project studied consists of the production of iron ore products from a mining company in Corumbá/MS, including mining, beneficiation and transportation of the processed ore by rail to the port of Santos/SP. Assumptions, input data and concepts to create a model that integrates the Stockyard of the Beneficiation Plant, Rail and Port are presented, beyond the outputs data of the model necessary for the assessment and analysis. Based on the results obtained were identified actions that can be taken to increase the efficiency of modeling work. The application of the proposed methodology allowed to demonstrate that an integrated simulation model, involving different activities of the mineral supply chain, provides an overview of the involved process and facilitates decision making.
54

Étude de l’interaction thermo-aéraulique entre un capteur PV et une pompe à chaleur (PAC) intégrés à un bâtiment basse exergie / Study of thermal-aeraulic interaction between a PV/T system and a heat pump integrated into a low exergy building

Ben Nejma, Hachem 25 September 2012 (has links)
Les contextes énergétique et environnemental actuels rendent nécessaire la réduction de la consommation en énergie primaire des secteurs énergivores tels que le secteur du bâtiment. Pour y parvenir, plusieurs études se sont penchées sur la réduction des besoins de chauffage et de climatisation. Mais un autre potentiel d'amélioration réside dans l'étude de la qualité de l'énergie employée pour répondre à ces besoins. En effet, le contenu exergétique des besoins du bâtiment étant faible, il est possible de réduire le contenu exergétique de l'énergie consommée par les systèmes assurant ces besoins. Cette réduction permet de baisser la consommation en énergie primaire.Dans cette optique, une étude des interactions thermiques possibles entre un capteur PV et une pompe à chaleur a été menée. Elle vise la valorisation de l'énergie thermique à faible contenu exergétique dissipée par les panneaux photovoltaïques. Des modèles aérothermique coté PV et semi-physique du système thermodynamique de la pompe à chaleur on été développés. Cette modélisation a permis la conception d'un système global composé d'un capteur PV-T hybride, d'une pompe à chaleur et d'un ballon de stockage. Son interaction est gérée en dynamique avec un modèle de bâtiment basse consommation via un outil de simulation thermique du bâtiment. Une étude énergétique et exergétique a permis d'évaluer le potentiel de ce système en le comparant avec des systèmes classiques. Un banc d'essai dédié à la validation du modèle de la pompe à chaleur a été réalisé. Une maison basse consommation a été construite. Le système conçu y a été installé et instrumentalisé. Les données recueillies ont permis une validation expérimentale du modèle global. / The energetic consumption of high consuming sectors such as the building sector should be reduced due to the actual environmental context. Many studies studied the reduction of heating and cooling capacities. But amelioration can be done when studying the exergy used. In fact, the exergetic content of energetic building demand is low. Then, it is possible to reduce the exergetic content of energetic systems used to match this demand. In this optic, a study of the possible thermal interaction between a PV system and a heat pump is lead. It aims to promote the thermal energy with a low exergetic content produced by the PV system. Aerothermal model for PV system and semi empirical model for heat pump system are used. Models help in the conception of a global system including a hybrid photovoltaic thermal PV system, a heat pump, and a storage device. A dynamic building model is used. Energetic and exergetic study allowed evaluating the potential of such a system. An experimental bench is used to validate the heat pump model. Experimental data coming from an experimental building are used to validate the global model results.
55

Using molecular dynamics simulations to study titration behavior of fatty acids

Baidya, Christina Autoshi January 2021 (has links)
Medium chain fatty acids (MCFAs) are essential molecules for a wide range of pharmaceutical, biotechnological, and industrial applications. These are naturally occurring saturated or unsaturated fatty acids containing 6-12 carbons with complex and pH sensitive aggregation. Medium chain fatty acids such as capric acid (C10) or lauric acid (C12) have additionally been shown to exhibit antibacterial activity. A number of studies have observed the aggregation behavior of long chain fatty acid using the titration curves by molecular dynamic (MD) simulations.  In this study, we performed constant-pH coarse-grained MD simulations to determine pKa values and titration behavior using a two-states model for C10 and C12. In the simulations, pH was varied between 2 to 8 and pKa values were determined using the Hill equation. The pKa for C10 (capric acid) was found to be 4.8 and for C12 (lauric acid) 5.4, in good agreement with the literature values (4.9 and 5.3, respectively).
56

Component development for a high fidelity transient simulation of a coal-fired power plant using Flownex SE

Le Grange, Willie 25 February 2019 (has links)
Large coal-fired power stations are designed to be run predominantly at full load and optimum conditions. The behaviour of plants, operating at low load and varying conditions, is getting more and more attention due to the introduction of variable renewable generation on the grid. Consequently, the need for a fully transient high-fidelity system based model has grown, as this will enable one to study the behaviour of plants under such non-ideal conditions. This report details the development of a feedwater heater, deaerator and turbine component for such a high-fidelity transient system model using the Flownex Simulation Environment, a onedimensional thermohydraulic network solver. The components have been modelled all with the aim of using minimal design input data. The feedwater heater component model includes transient effects and thermodynamic relations to represent aspects such as heater performance, level control and transient inertia. In determining the heat transfer characteristics, the model makes use of plant-performance data and correlates the amount of heat transfer by using the feedwater mass flow as the load indicating parameter. This approach eliminates the need for specific geometrical details to calculate the effective heat transfer area. The level control is modelled by using a level representation built from using heat exchanger design methods. The turbine component is modelled by using Fuls’ Semi-Ellipse law or the pressure drop modelling and Ray’s semi-empirical method for the efficiency modelling. The model also contains transient effects, which include thermal inertia due to the shaft and casing, and rotational inertia due to the shaft. The deaerator component is modelled by adapting the model presented by Banda, and modifying the model to work under various conditions. This involved using curve fit methods in Flownex to use input data to model the pressure drop over the main condensate valve. Each of the mentioned components was validated and verified with plant data and finally packaged into a compound component which is a component consisting of a subnetwork in Flownex. These compound components further contain design inputs which are easily accessible by the user. The component models were integrated into larger networks in which various scenarios can be run. A short transient scenario was run on the low-pressure feedwater train of a specific power station. The scenario involved a turbine trip where the bled steam valves for the heaters were closed suddenly. The speed of the valves closing was however unknown and after closing the valves in approximately 10 seconds, results agreed relatively well with plant data. This illustrated the short transient capabilities of the feedwater heater component model. The three component models (feedwater heater, turbine and deaerator) were finally integrated into a regenerative Rankine cycle and was set up using minimal design data. The boiler, condenser and condensate pump were set as boundary conditions in the network but all extraction points for the network were connected. Steady-state results were obtained for various load cases and the main temperature, flow and pressure results were compared. Results agree well with plant data, even at low load conditions
57

Design of Magnetic Tumbling Microrobots for Complex Environments and Biomedical Applications

Chenghao Bi (8043773) 27 November 2019 (has links)
The mobility and biomedical applications of a microscale magnetic tumbling (μTUM) robot capable of traversing complex terrains in dry and wet environments is explored. Roughly 800 x 400 x 100 μm in size, the robot is fabricated using standard photolithography techniques and consists of a rectangular polymeric body with embedded NdFeB particles. Static force analysis and dynamic modeling of its motion characteristics are performed with experimental verification. Techniques for simulating the intermittent, non-contact behavior of tumbling locomotion are used to find an optimized design for the microrobot, reducing time and resources spent on physical fabrication. When subject to a magnetic field as low as 3 mT, the microrobot is able to translate at speeds of over 30 body lengths/s (24 mm/s) in dry conditions and up to 8 body lengths/s (6.8 mm/s) in wet conditions. It can climb inclined planes up to 60° in wet conditions and up to 45° in dry conditions. Maximum open loop straight-line trajectory errors of less than 4% and 2% of the traversal distance in the vertical and horizontal directions, respectively, were also observed. Full two-dimensional directional control of the microrobot was shown through the traversal of a P-shaped trajectory. The microrobot's real-time position can be accurately tracked through visual occlusions using ultrasound imaging. When applied as a coating, a fluorescein payload was found to diffuse over a two hour time period from the microrobot. Cytotoxicity tests also demonstrated that the microrobot's SU-8 body is biocompatible with murine fibroblasts. The microrobot's capabilities make it promising for targeted drug delivery and other in vivo biomedical applications.
58

La Sarcolipine, un régulateur de l’ATPase-Ca2+ SERCA1a : études in silico / Sarcolipin, a Regulator of Ca2+-ATPase SERCA1a : in Silico Studies

Barbot, Thomas 15 June 2018 (has links)
La Sarcolipine (SLN) est un hélice transmembranaire de 31 résidus dont la function est de reguler l’ATPase-Ca2+ SERCA1a. Ce régulateur peut subir une modification post-traductionnelle chez certaines espèces. Par exemple, chez le lapin, il est palmitoyle ou oleoylé sur le résidu Cys9. Pour comprendre au niveau moléculaire l’effet de cette modification post-traductionnelle sur la SLN, nous avons réalisé des simulations de dynamique moléculaire de la SLN de lapin insérée dans une bicouche de 1-palmitoyl-2-oléoyl-sn-glycéro-3-phosphocholine (POPC), non acylée et palmitoylée. L’analyse de ces simulations démontre que la palmitoylation n’affecte pas la structure secondaire, l’orientation (tilt et azimut), ainsi que l’enfouissemnt de la SLN dans la membrane. De plus, l’analyse de simulations tout atome de la SLN humaine insérée dans une bicouche de POPC montre que la SLN humaine a la même structure secondaire et orientation que la SLN de lapin mais est plus enfouie dans la membraneque celle de lapin, du fait de sa sequence en acides amines N-terminale plus hydrophobe.L’ATPase-Ca2+ SERCA1a, une ATPase de type P, est localisée dans la membrane du reticulum sarcoplasmique des cellules du muscle squelettique. Elle est impliquée dans les processus de contraction/relaxation musculaire en transportant rapidement le Ca2+ cytosolique dans le lumen du reticulum sarcoplasmique grâce à l’énergie fournie par l’hydrolyse de l’ATP. D’importants changements conformationnels de SERCA1a ont lieu durant son cycle catalytique comme le montrent les nombreuses structures cristallines de SERCA1a. En particulier, à l’état E1, la cavité contenant les sites de fixation du Ca2+ est ouverte vers le cytoplasme, tandis qu’à l’état E2, cette cavité est ouverte vers le lumen. La transition de l’état E1 à E2 nécessite la phosphorylation du résidu Asp351. Des structures 3D du complexe SERCA1a-SLN ont été déterminées par diffraction aux rayons X avec SERCA1a dans un état E1-Mg2+. Pour comprendre le mécanisme détaillé de la regulation de SERCA1a par la SLN, des simulations de dynamique moléculaire et des analyses des modes normaux (NMA) ont été réalisées en utilisant la structure 3D du complexe SERCA1a-SLN inséré dans une bicouche de POPC. Les résultats principaux de ces analyses sont les suivants : 1) la SLN régule les transitions E1.Mg2+ → E1.2Ca2+ et E1.Mg2+ → E2 ; 2) l’interaction de la SLN influe sur la structure et la dynamique de SERCA1a et modifie la position de l’hélice transmembranaire TM1 de sorte à ce que la cavité contenant les sites de fixation du Ca2+soit plus ouverte et que les sites soient plus accessibles ; 3) l’interaction de la SLN avec TM6 affecte deux regions de SERCA1a indispensables à sa fonction : en modifiant la structure et la dynamique de TM6, la SLN perturbe la position et la fluctuation des résidus des sites de fixation du Ca2+, leur conférant une conformation inapte à fixer le Ca2+. De même, l’interaction avec TM6 induit la courbure de TM5, ce qui affecte de façon indirecte le site de phosphorylation (éloigné de plus de 35 Å de la SLN) et conduit à l’inhibition de la phosphorylation du résidu Asp351.Nos résultats de cette étude in silico fournissent de nouveaux éléments concernant le mécanisme par lequel la SLN régule SERCA1a et qui pourrait être complétés par des travaux expérimentaux. / Sarcolipin (SLN), a transmembrane helix of 31 residues, binds to and regulates the Ca2+-ATPase SERCA1a. This regulator is post-translationnally modified in some species. For example, in rabbit, it is palmitoylated or oleoylated on its Cys9 residue. To understand at a molecular level, the effect of this post-translationnal modification on SLN, all-atom molecular dynamics simulations of unacylated and palmitoylated rabbit SLN embedded in a POPC bilayer were performed. Analysis of the simulations demonstrates that palmitoylation does not affect the secondary structure, the orientation (tilt and azimuth) as well as the burying of SLN within the membrane. In addition, the analyses of all-atom simulations of human SLN embedded in a POPC bilayer show that human SLN has the same secondary structure and orientation as rabbit SLN but is more buried within the membrane than rabbit SLN as a result of its more hydrophobic N-terminal amino acids sequence.The Ca2+ pump SERCA1a, a P-type ATPase, is localized in the sarcoplasmic reticulum membrane of striated muscle cells. It is involved in the contraction/relaxation process by fast pumping the cytoplasmic Ca2+ from the cytosol to the lumen of the sarcoplasmic reticulum using the energy of ATP hydrolysis. Large conformational changes of SERCA1a occur during its catalytic cycle as evidenced by the various crystal structures of SERCA1a. In particular, in the E1 state, the cavity that contains the Ca2+ binding sites is open toward the cytoplasm while in the E2 state, this cavity is open toward the lumen. The transition from the E1 to the E2 state involves the phosphorylation of Asp351 residue. 3D structures of SERCA1a-SLN complex have been determined by X-Ray diffraction, with SERCA1a in a E1-Mg2+ state. To understand the detailed mechanisms of SERCA1a regulation by SLN, molecular dynamics (MD) simulations and normal mode analysis (NMA) were performed using the 3D structures of SERCA1a-SLN complex embedded in a POPC bilayer. Main results from these analyses are the followings: 1) SLN regulates the E1-Mg2+ → E1-2Ca2+ and E1-Mg2+ → E2 state transitions; 2) interaction of SLN with SERCA1a impact the structure and dynamic of SERCA1a and modifies the position of the transmembrane helix TM1 such that the cavity that contains the Ca2+ binding sites is more widely opened and the Ca2+ binding sites more accessible; 3) SLN interaction with affects two regions essential to its function. By changing the structure and dynamic of TM6, SLN alters the position and fluctuations of residues involved in the Ca2+ binding sites, such that those sites are unable to bind Ca2+. This interaction with TM6 also induces TM5 bending and thus, indirectly modifies the phosphorylation site conformation, leading to the inhibition of Asp351 phosphorylation.Our results from these in silico studies provide new insights into the mechanism by which SLN regulates SERCA1a activity and could be completed by experimental work.
59

Development of a methodology of Dynamic LCA applied to the buildings / Développement d’une méthodologie d’ACV dynamique appliquée aux bâtiments

Negishi, Koji 21 June 2019 (has links)
Le secteur du bâtiment est un acteur clé pour aider la France à atteindre ses objectifs de réduction en matière de consommation d’énergie et d’émissions de gaz à effet de serre (GES). L’analyse du cycle de vie (ACV) est la méthode la plus utilisée pour évaluer les impacts environnementaux d’un produit ou d’un système d’une manière systématique et holistique sur l’ensemble de son cycle de vie. Dans le secteur du bâtiment, la méthode ACV a été adaptée avec des outils appropriés, simplifiés, pour inciter les acteurs du bâtiment à évaluer la performance environnementale de leur produit. Cependant, la méthode ACV présente des limites dont une est le manque de notion de « temps », qui touche notamment trois points : (i) Manque de considération de l’évolution temporelle des systèmes, du système « bâtiment » dans notre cas, (ii) Non prise en compte du décalage temporel des activités et donc des émissions, and (iii) Non prise en compte du caractère dynamique des impacts environnementaux. Dans ce contexte, l’objectif de la thèse est de développer une méthodologie d’ACV dynamique appliquée au bâtiment, qui permet de prendre en compte ces trois aspects dynamiques, sur la base du projet ANR DyPLCA. L’application de la nouvelle méthode dynamique à un cas d’étude avec trois maisons individuelles accolées a permis d’obtenir des informations importantes sur le profil temporel des impacts. La même quantité des émissions de GES a un impact de changement climatique plus bas lorsque les émissions sont réparties sur une période longue. Les actions pour la réduction et l’adaptation doivent être décidées selon différents types de famille de produits de construction. Ainsi, il est nécessaire d’adapter les efforts de réduction d’impacts en fonction des substances chimiques. / The building sector is a key actor to meet the reduction targets in terms of energy consumption and greenhouse gases (GHG) emissions. Life Cycle Assessment (LCA) is the most used method for assessing the environmental impacts of a system. In the building sector, the LCA method was adapted with appropriate and simplified tools in order to encourage stakeholders to evaluate the environmental performance of their building products. However, LCA method has some limitations, one of which being the lack of “time dimension” that particularly concerns three points: (i) Lack of consideration of temporal evolution of the system under LCA study, “building system” in our case, (ii) Lack of consideration of temporal discrepancy of activities and associated emissions, (iii) Lack of consideration of dynamic characteristics of environmental impacts (stationary conditions, fixed time horizon, etc.). In this context, the primary objective of the thesis is to develop a dynamic LCA methodology applied to the building sector, on the basis of DyPLCA ANR project. The application of the new dynamic method to a case study with three attached single houses demonstrated that dynamic LCA provides important information on the temporal profile of impacts. The same amount of GHG emissions has a lower effect on temperature peaks when emissions are spread over a long period. The distinction is made between the various GHG, especially according to their lifetime. Instantaneous and cumulated effects (indicators) should be considered in a complete analysis. Actions for mitigation and adaptation need to be decided according to different types of construction product families. Besides, it is necessary to adapt the impact reduction efforts according to the chemical substances.
60

Optimierung der Prozessführung von Kraftwerken unter Oxyfuelbedingungen mittels Simulationsmodellen

Tusche, Peter 24 October 2014 (has links)
In dieser Arbeit werden unter der Nutzung von Simulationswerkzeugen und neu erstellten instationären Modellen von Kraftwerkskomponenten auf dem Sektor der Energieerzeugung mit fossilen Brennstoffen am Beispiel von Kohle, Betriebs- und Verhaltensweisen der Anlage untersucht und Optimierungsmöglichkeiten für die vorgegebenen Randbedingungen getestet.

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