Дисертації з теми "Transfer Optimisation"
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Sobotka, Vincent. "Optimisation thermique du procédé Resin Transfer Molding." Nantes, 2004. http://www.theses.fr/2004NANT2094.
Повний текст джерелаStructural composite materials manufactured with continuous reinforcement (either woven or long fibers) are more and more used, notably in the car industries, aeronautical, nautical and sports domains. The Resin Transfer Molding process is a process of composite part manufacture adapted to average production corresponding more and more to those met in car industries. Besides, this process complies with the environmental requirements of solvent release, molding being achieved in closed mold. This work achieved within the framework of the Programs of Research and Innovation in Ground Transport (PREDIT) of the Ministry of National Education associated several academic and industrial partners. It concerned the thermal characterization of composite materials made of unsaturated polyester and glass reinforcements, as well as their transformation. Experimental analyses were carried out by in-situ measures as well as the modelling of the heat transfer in the process. Some new models have been developed and have been validated. A first illustration of a methodology of thermal optimization of the process has been shown
Thompson, Seth Mkhanyisi. "Optimisation of insertion point during latissimus dorsi tendon transfer." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29524.
Повний текст джерелаMcNab, Christopher. "Design optimisation of internally finned tube charge-air coolers." Thesis, University of Brighton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246001.
Повний текст джерелаObame, Mve Herbert. "Compréhension des écoulements et optimisation des transferts de chaleur et de masse au sein d’une structure capillaire." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0052/document.
Повний текст джерелаAbstract The automotive air conditioning is a major challenge for the automotive manufacturers insofar it causes a release of 10 g/CO2/km, engenders an extrafuel consumption of 5 % and will be taken into account in the balance sheet in 2020 MEVG. In this perspective, the automotives constructor PSA Peugeot Citroën has developed a new process, absorption air conditioning of water vapor by lithium bromide solution, which marks a break with the classic vapor-compression system. This manuscript is focused at the main body of the system, an innovative evaporator/absorber where both fluids are flowing down and confined between two finely meshed plastic wire screens and maintained between them by capillary effects. The heat and mass transfers in this system occur at the liquid/vapour interface formed by complex menisci that represent the surface of transfer. An experimental test bench allowing the description of three-dimensional shape of menisci using confocal microscopy has been carried. The volume of fluid model has been used for the numerical reconstruction of the liquid/vapour interface. The comparison between numerical and experimental data has shown a good agreement. Numerical simulations have shown that the flow is influenced by the geometry that promotes the creation of stagnant layer solution and vorticity zones. A numerical optimization has been carried with as objective function the heat rate that di uses through the interface. This one has allowed to get out the optimal parameters allowing to have an heat rate of more than 2.5 times higher compared to the reference case. This optimization has highlighted a preferential zone in which heat transfers are maximum. The work has also dealt with the e ect of the shape of the wires and the effect of the shape of menisci on the transfer, showing that it is preferable to work with hydrophobic materials and with cylindrical wires
Pohl, Julien. "Turbine stator well heat transfer and design optimisation using numerical methods." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/15939/.
Повний текст джерелаMujanayi, Katumba Jean-Marc. "Thermal management and optimisation of heat transfer from discrete heat sources." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/61318.
Повний текст джерелаDissertation (MSc)--University of Pretoria, 2016.
Mechanical and Aeronautical Engineering
MSc
Unrestricted
Alfama, Marco. "Theoretical and experimental investigation of the heat transfer and pressure drop optimisation on textured heat transfer surfaces." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/62792.
Повний текст джерелаDissertation (MEng)--University of Pretoria, 2017.
Mechanical and Aeronautical Engineering
MEng
Unrestricted
Barrut, Bertrand. "Etude et optimisation du fonctionnement d’une colonne airlift à dépression - Application à l’aquaculture." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20125.
Повний текст джерелаThe aim of this work was to study the three functions of a vacuum airlift, which are water pumping, mass transfer and foam fractionation. The investigations mainly focused on the treatment of fish culture water and on phytoplancton harvesting. Each function was studied separately, in order to assess the performance of the vacuum airlift with specific operating conditions. By studying the airlift pump, the effects of water and diffuser types, air injection conditions and depression level were shown. In fresh water, bubble coalescence was observed, which reduced gas holdup compared to sea water. Consequently, the water flow of the vacuum airlift appeared higher in fresh water than in sea water (30 to 35 m3.h-1 against 10 to 20 m3.h-1) for the same air flow rate (5 m3.h-1). Conversely, the available lift height was higher in sea water (up to 0.8 m) than in fresh water (0.6 m maximum). For low head aquaculture systems, the vacuum airlift may be an economical pumping system which allows a 40 % energy saving compared to centrifugal pumps. The vacuum airlift had a mass transfer efficiency similar to other gas transfer systems. The KLa values calculated for CO2 desorption ranged between 0.002 and 0.01 s-1. They were four times lower than those obtained for oxygen transfer in similar conditions. Mass transfer efficiencies ranged between 0.02 and 0.023 Kg.KW.h-1 for CO2 and between 1.52 and 1.8 Kg.KW.h-1 for O2. Mass transfer velocities significantly depended on air flow rate, water temperature, average bubble size and the presence of feed in the rearing tank. They are weakly depending on salinity, depression level, inner tube length or water flow. At last, foam fractionation increased when air flow and bubble size were reduced. The extraction efficiency decreased when the concentration of the extracted product increased (maximal concentration factor around130). The vacuum airlift appeared to be as a high-performance multifunctional system, even if the maximal efficiency for each of the functions corresponds to different operating conditions. This process could be used in a large scope of fields ranging from aquaculture to industrial water treatment
Lindqvist, Camilla. "Genetic Engineering of T Lymphocytes for Cancer Immunotherapy : Optimisation of Gene Transfer." Thesis, Uppsala University, Department of Medical Biochemistry and Microbiology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7139.
Повний текст джерелаT lymphocytes can be rendered specific against a wide range of antigens by the genetic transfer of a chimeric receptor, a fusion between the antigen-binding domain of an antibody and the signalling domain of a T cell receptor. The use of such chimeric T lymphocytes has shown promising results for cancer therapy. Previous experiments in our laboratory have shown low rates of gene transfer using retroviral vectors. In this study, investigations have been done to increase the number of genetically modified cells. Different enhancers such as PLL and polybrene have previously been used in combination with retroviral transduction. The optimal retroviral protocol in this study showed to be the use of retrovectors produced with twice the normal concentration of the plasmids encoding env and gag-pol rather than the use of the enhancers. A 6-day pre stimulation of T lymphocytes prior transduction together with a centrifugation step increased the rate of modified cells even further. Alternative approaches of gene transfer were also investigated, including plasmid transfection and adenoviral transduction. While transfection protocols yielded low numbers of modified cells, adenoviral vectors showed the highest rate of gene transfer.
Cancer är den sjukdom som idag, efter hjärt-kärl-sjukdomar, kräver flest dödsfall i i-länder. Som en alternativ behandlingsmetod mot cancer pågår just nu forskning om genetiskt förbättrade immunceller, s.k. chimära T lymfocyter, skulle kunna användas för att döda tumörceller. De chimära cellerna är utrustade med en konstgjord receptor som är en fusion av en antikropp och en signalkedja. Det gör att cellerna kan riktas mot ett brett urval av cancertyper. Att få cellerna att ta upp generna som behövs för den konstgjorda receptorn har visats sig vara problematiskt. Den här studien har därför som mål att förbättra cellernas förmåga att ta upp gener. För detta har vi använt oss av retrovirus- och adenovirus-system tillsammans med försök att få cellerna att spontant ta upp generna, sk. plasmid-transfektion. Studien har visat att de båda virussystemen ger högst antal modifierade celler. Olika substanser som tidigare har visat sig förhöja graden av gentillförsel har testats, men vår studie har visat att tillverkningen av virusvektorerna har större påverkan på resultaten än någon av de olika hjälpmedlen.
Vicatos, George. "Heat and mass transfer characteristics: design and optimisation of absorption refrigeration machines." Doctoral thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/17476.
Повний текст джерелаAn extensive literature study on the subject of absorption refrigeration has revealed that there is no proven methodology that can be used to design, optimise and size a plant. On the contrary there are numerous methods which analyse the performance of an existing plant from collected data. These methods however, do not provide any means of predicting how the analysed plant would perform if one or more of its working conditions should change. This work provides a complete design for an ammonia-water absorption refrigeration plant. The ranges of the working conditions in the evaporator and condenser are from -5°C to -55°C and from 5°C to 45°C respectively. For any combination of temperatures within these ranges, the temperature of the generator is optimised for maximum performance of the plant. Depending on the refrigeration capacity, the components are sized and designed. The proper design of the various components takes into account both heat and mass transfer correlations, something which has not been considered in the past as a necessary step for absorption refrigeration machines. Literature indicates that there is a vast amount of research into the absorption of gases into liquids and two-phase flows through tubes of various sections. The correlations cited in these studies have been used in designing the absorption column, evaporator and generator. The proposed optimisation method is a novel approach in designing a plant and stems from the fact that the performance of the absorption refrigerator reaches a maximum at a specific generator temperature. For this, optimisation curves have been developed, which for a particular combination of evaporator and cooling environment temperatures, both the optimum generator temperature and the maximum performance of the plant are predicted. The equations used in the computerised simulation procedure are based on the well-established enthalpy-concentration chart for the ammonia-water mixtures. Thus the properties of the mixture at various points in the plant are accurately predicted. Published computerised procedures in the past have been proven inaccurate in predicting the properties of the mixtures at near pure-ammonia concentrations. The validity of the simulation model is verified by tests performed on a laboratory size absorption plant. The plant was built from design parameters predicted by the simulation model for a refrigeration capacity of 1 kW at -l5°C evaporator coil and 25°C condensate temperatures. Thereafter the unit was operated for a range of evaporator conditions while the generator temperature was varied.
Van, Aarde Michiel Nicolaas. "The optimisation of transfer chutes in the bulk materials industry / M.N. van Aarde." Thesis, North-West University, 2009. http://hdl.handle.net/10394/5061.
Повний текст джерелаThesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2010.
Stocks, Marc Darren. "Geometric optimisation of heat transfer in channels using Newtonian and non-Newtonian fluids." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/33348.
Повний текст джерелаDissertation (MEng)--University of Pretoria, 2012.
gm2014
Mechanical and Aeronautical Engineering
unrestricted
Quintero, Garcia Karla Rossa. "Optimisation d'alignements d'un réseau de pipelines basée sur les algèbres tropicales et les approches génétiques." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0030/document.
Повний текст джерелаThis thesis addresses operations optimization in an oil seaport with the fundamental purpose of assisting supervision operators. The objective is to provide candidate solutions for pipeline alignment (path) selection and for scheduling of oil transfer operations, as well as maintenance operations, considering that the system has limited and conflicting resources. Informed decision making should consider operations scheduling and alignment selection based on : devices availability, operative capacity of the network, financial aspects (penalties) due to late service, and a predefined maintenance schedule. The optimization problem is addressed by tropical approaches given their potential for yielding concise and intuitive representations when modeling synchronization phenomena. The proposals developed herein start by algebraic mono-objective optimization models. They subsequently become more complex, as new aspects are included, leading to the formulation of hybrid multi-objective optimization models based on artificial intelligence approaches as well as (max,+)-linear system theory. Firstly, a mono-objective optimization model is proposed in (max,+) algebra for penalty minimization. This model integrates different nature phenomena into one single constraint. It is nonlinear, considers predefined alignments for transfer operations and is validated through an optimization solver (LINGO). Secondly, linearization of such model is introduced for prioritization of conflicting operations. Within this context, 2 criteria are addressed: potential penalties for clients and, on the other hand, operations criticality. The nonlinear (max,+) model minimizing penalties is extended in order to consider alignment search and delay minimization for maintenance operations. In order to address the multi-objective nature of the problem, an approach based on genetic algorithms and (max,+)-linear system theory is proposed. Finally, in a more formal framework, a new synchronous product for tropical automata exploiting parallelism phenomena at the earliest is defined in order to minimize the makespan. The proposed models and methods herein have been validated by industrial data gathered from the oil company PDVSA and from the supervision solutions provider Thales Group. The main contributions of this research are, firstly, the application of tropical approaches to this specific optimization problem, yielding concise and potentially linear models. Secondly, the proposal of a hybrid approach based on genetic algorithms and (max,+)-linear systems, which exploits the advantages of the distributed search of artificial intelligence approaches and the conciseness of the models stemming from (max,+) algebra. The final contribution focuses on the definition of the alphabet for a new synchronous product of tropical automata
Engels, Boris. "Optimisation of retroviral gene transfer in T lymphocytes for the redirection of PBL-specificity." [S.l.] : [s.n.], 2005. http://www.diss.fu-berlin.de/2005/260/index.html.
Повний текст джерелаKamci, Hamdi. "Optimisation Of Agrobacterium Mediated Gene Transfer And Micrografting Systems In Lentil (lens Culinaris Medik)." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605460/index.pdf.
Повний текст джерелаtype and intensity of injury, type of pre-incubation media for injured explants, effect of evacuation, effect of L-cysteine during co-cultivation and Agrobacterium incubation duration. According to the results crushing type of injury was superior over the poking and sonication type of injuries. Following the injury Hogland`s solution was used as pre-incubation media prior to infection. The effect of evacuation parameter was found to be insignificant whereas the effect of L-cysteine during co-cultivation was negative on the transformation efficiency. According to the Agrobacterium incubation duration studies, 240 minutes, followed by 120 minutes of Agrobacterium incubation were the most efficient in terms of transformation efficiency. However, since there was no significant difference among the two 120 minutes chosen to be the optimum bacterial incubation duration.
Deivakkannu, Ganesan. "Data acquisition and data transfer methods for real-time power system optimisation problems solution." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/1178.
Повний текст джерелаThe electric power utilities play a vital role in the generation, transmission and distribution of the electrical power to the end users. The power utilities face two major issues, i.e. i) power grids are expected to operate close to the maximum capacity, and ii) there is a need for accurate and better monitoring and control of the power system network using the modern technology and the available tools. These two issues are interconnected as better monitoring allows for better control of the power system. Development of the new standard-based power system technologies contributed to raising the ideas for building of a Smart grid. The challenges are that this process requires development of new control and operation architectures and methods for data acquisition, data transfer, and control computation. These methods require data for the full dynamic state of the power system in real-time, which leads to the introduction of the synchrophasor-based monitoring and control of the power system. The thesis describes the research work and investigations for integration of the existing new power system technologies to build fully automated systems for real-time solution of power system energy management problems, incorporating data measurement and acquisition, data transfer and distribution through a communication network, and data storage and retrieval in one whole system.
Olakoyejo, O. T. (Olabode Thomas). "Geometric optimisation of conjugate heat transfer in cooling channels with different cross-sectional shapes." Thesis, University of Pretoria, 2012. http://hdl.handle.net/2263/25484.
Повний текст джерелаThesis (PhD(Eng))--University of Pretoria, 2012.
Mechanical and Aeronautical Engineering
unrestricted
Williamson, N. J. "Numerical modelling of heat and mass transfer and optimisation of a natural draft wet cooling tower." Connect to full text, 2008. http://ses.library.usyd.edu.au/handle/2123/4035.
Повний текст джерелаTitle from title screen (viewed February 12, 2009). Includes graphs and tables. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Aerospace, Mechanical and Mechatronic Engineering. Includes bibliographical references. Also available in print form.
Santosa, I. Dewe. "Optimisation gas coolers for CO2 refrigeration application." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/12161.
Повний текст джерелаWilliamson, Nicholas J. "Numerical modelling of heat and mass transfer and optimisation of a natural draft wet cooling tower." University of Sydney, 2007. http://hdl.handle.net/2123/4123.
Повний текст джерелаThe main contribution of this work is to answer several important questions relating to natural draft wet cooling tower (NDWCT) modelling, design and optimisation. Specifically, the work aims to conduct a detailed analysis of the heat and mass transfer processes in a NDWCT, to determine how significant the radial non-uniformity of heat and mass transfer across a NDWCT is, what the underlying causes of the non-uniformity are and how these influence tower performance. Secondly, the work aims to determine what are the consequences of this non-uniformity for the traditional one dimensional design methods, which neglect any two-dimensional air flow or heat transfer effects. Finally, in the context of radial non-uniformity of heat and mass transfer, this work aims to determine the optimal arrangement of fill depth and water distribution across a NDWCT and to quantify the improvement in tower performance using this non-uniform distribution. To this end, an axisymmetric numerical model of a NDWCT has been developed. A study was conducted testing the influence of key design and operating parameters. The results show that in most cases the air flow is quite uniform across the tower due to the significant flow restriction through the fill and spray zone regions. There can be considerable radial non-uniformity of heat transfer and water outlet temperature in spite of this. This is largely due to the cooling load in the rain zone and the radial air flow there. High radial non-uniformity of heat transfer can be expected when the cooling load in the rain zone is high. Such a situation can arise with small droplet sizes, low fill depths, high water flow rates. The results show that the effect of tower inlet height on radial non-uniformity is surprisingly very small. Of the parameters considered the water mass flow rate and droplet size and droplet distribution in the rain zone have the most influence on radial noniv uniformity of heat transfer. The predictions of the axisymmetric numerical model have been compared with a one dimensional NDWCT model. The difference between the predictions of tower cooling range is very low, generally around 1-2%. This extraordinarily close comparison supports the assumptions of one dimensional flow and bulk averaged heat transfer implicit in these models. Under the range of parameters tested here the difference between the CFD models predictions and those of the one dimensional models remained fairly constant suggesting that there is no particular area where the flow/heat transfer becomes so skewed or non-uniform that the one dimensional model predictions begin to fail. An extended one dimensional model, with semi-two dimensional capability, has been developed for use with an evolutionary optimisation algorithm. The two dimensional characteristics are represented through a radial profile of the air enthalpy at the fill inlet which has been derived from the CFD results. The resulting optimal shape redistributes the fill volume from the tower centre to the outer regions near the tower inlet. The water flow rate is also increased here as expected, to balance the cooling load across the tower, making use of the cooler air near the inlet. The improvement has been shown to be very small however. The work demonstrates that, contrary to common belief, the potential improvement from multi-dimensional optimisation is actually quite small.
Aussignargues, Clement. "Optimisation du métabolisme énergétique du soufre chez la bactérie hyperthermophile Aquifex aeolicus." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4709/document.
Повний текст джерелаSulfur can be used in energy metabolism by microorganisms as electron donor and acceptor. The hyperthermophilic bacterium Aquifex aeolicus, which need oxygen, hydrogen and an essential sulfur compound for its growth presents sulfur reduction and oxidation pathways linked to the energy synthesis. A sulfur reductase (reduction of sulfur chains), a Sulfide Quinone Oxidoreductase (SQR, oxidation of H2S) and a Sulfur Oxygenase Reductase (SOR, simultaneous oxidation and reduction of sulfur chains) have been characterized in this bacterium. It has also been shown that some of these enzymes are organized in membrane-bound supercomplexes.We have demonstrated that Aq_477, previously characterized as a sulfurtransferase belonging to the rhodanese superfamily, can load long sulfur chains and acts as a sulfur donor for its partners (sulfur reductase and SOR) which use these sulfur chains as substrate, thus optimizing the metabolism. These results show that Aq_477, renamed SbdP for Sulfur -binding -donating Protein, is involved in the sulfur energy metabolism of Aquifex aeolicus. The identification in the genome of some new proteins potentially involved in this metabolism permitted us to propose a new model which suggests a recycling of sulfur compounds between different enzymatic systems. We also looked for an organization level of respiratory complexes higher than supercomplexes, which led us to develop new study methods and propose several research trails. Finally, we have shown the existence of protein nanocompartment constituted by the encapsulin Aq_1760, in which the atypical tandem-domain ferritin Aq_331 is anchored
Barbary, Delphine. "Optimisation topologique des transferts thermiques et massiques dans un canal asymétriquement chauffé." Thesis, La Réunion, 2017. http://www.theses.fr/2017LARE0038/document.
Повний текст джерелаThis thesis deals with topology optimization of mass and heat transfer in the framework of the vertical asymetrically-heated channel. The incompressible Navier-Stokes equations coupled to the convection-diffusion equation through the Boussinesq approximation are employed and are solved with the finite volume method. We first propose a new interpolation technique for heat transfer optimization and validate it on referenced cases such as the "single pipe" and the "bend pipe". This new technique consists in the introduction of sigmoid interpolation functions to obain a better definition of the interface between fluid and solid domains, during the optimization process. We study then physical phenomenon in the asymmetrically heated channel , in particular the influence of thermal stratification outside the channel and surface radiation on thermal and dynamic quantities. We thus highlight the size variation of reversed flow at the exit of the channel and the plug-effect linked on external thermal stratification. Finally, we propose a new expression of mechanical power in order to control charges losses (despite addition of material) in the vertical channel combined with the expression of thermal power. In all considered cases, our algorithm succeeds to enhance one of the phenomenon modelled by our new cost functions without deteriorating the other one. We also compare the values of standard cost functions from the litterature over iteration of our optimization algorithm and show that our new cost functions are effective
Bire, Solenne. "Optimisation de la biosécurité du vecteur transposon piggyBac pour le transfert de gène : utilisation des ARN messagers et des insulateurs." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4043.
Повний текст джерелаAdvances in biotechnology have enabled the development of tools for gene transfer applicable to transgenesis, bioproduction and gene therapy. But, 3 major challenges must be met to ensure a secure system: the safety and effectiveness of the transfer. the targeted and controlled integration into the genome. and the level of transgene expression over time. In this aim, my thesis project was to validate solutions to improve the biosafety of the piggyBac transposon, which requires a plasmid carrying the gene of interest to be inserted in the genome, and a source of transposase which catalyzes the transgene integration. One approach of my thesis work is to deliver the source of piggyBac transposase as an mRNA molecule instead of DNA. This strategy aims to improve the stability of the integration and reduce the genotoxic effects by limiting the transposase in the cells. For the 1st time, the bioavailability of the transposase rnRNA and the optimal conditions for its use in human cells were determined to increase the biosafety of the transposon system. The 2nd objective ofmy project is to improve the expression of the transgene by adding insulators known to counteract the transgene silencing. This strategy reduces the number of integrations required ta get a sufficient expression of the transgene and thus, improve biosecurity. Two candidates have been identified to improve transgene expression. The combination of the mRNA and insulator strategies is promising to secure the piggyBac-mediated gene transfer and to maintain the expression of the gene of interest
Peng, Zhihao. "Optimisation par essaims particulaires pour la logistique urbaine." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCA010/document.
Повний текст джерелаIn this thesis, we are interested in the management of goods flows in urban areas, also called last mile logistics, and associated with various current issues: economic, environmental, and societal. Four main stakeholders are involved by these challenges: shippers, customers, carriers and local authorities, each with different priorities (improving service quality, minimizing the travelling distance, reducing greenhouse gas emissions, etc.). Faced with these challenges in the city, one possible action lever is to optimize the routes for the pickup and/or delivery of goods. Three types of urban flows are considered: from or to the city, and intra-urban. For outgoing and incoming flows into the city, the goods are first grouped in a warehouse located on the suburban area of the city. If there are several warehouses, the associated planning problem is the Location Routing Problem (LRP). We are studying one of its variants called the Capacitated Location Routing Problem (CLRP). In this problem, by respecting the capacity constraint on vehicles and depots, the location of depots and route planning are considered at the same time. The objective is to minimize the total cost, which consists of the cost of opening depots, the cost of using vehicles, and the cost of the travelling distance. For all flows, we are also looking to solve a Pickup and Delivery Problem (PDP), in which a fleet of vehicles simultaneously carries out pickup and delivery operations. We focus on two of its variants: the selective variant where not all requests are satisfied, in a context of paired demands and time windows on sites (Selective Pickup and Delivery Problem with Time Windows and Paired Demands, or SPDPTWPD). The second studied variant is the extension of the first one by adding the possibility of carrying out transport in several stages by introducing operations for the exchange of goods between vehicles at transfer sites (Selective Pickup and Delivery with Transfers or SPDPT). The considered objectives for these two variants of PDP are to maximize profit and to minimize distance. Each studied problem is formally described, mathematically modelled as a linear program and then solved by exact, heuristic and/or metaheuristic methods. In particular, we have developed algorithms based on a metaheuristic called Particle Swarm Optimization, which we have hybridized with local search operators. The approaches are validated on instances of different sizes from the literature and/or on instances that we have generated. The results are critically analyzed to highlight the advantages and drawbacks of each method
Bertrand, Hadrien. "Optimisation d'hyper-paramètres en apprentissage profond et apprentissage par transfert : applications en imagerie médicale." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT001/document.
Повний текст джерелаIn the last few years, deep learning has changed irrevocably the field of computer vision. Faster, giving better results, and requiring a lower degree of expertise to use than traditional computer vision methods, deep learning has become ubiquitous in every imaging application. This includes medical imaging applications. At the beginning of this thesis, there was still a strong lack of tools and understanding of how to build efficient neural networks for specific tasks. Thus this thesis first focused on the topic of hyper-parameter optimization for deep neural networks, i.e. methods for automatically finding efficient neural networks on specific tasks. The thesis includes a comparison of different methods, a performance improvement of one of these methods, Bayesian optimization, and the proposal of a new method of hyper-parameter optimization by combining two existing methods: Bayesian optimization and Hyperband.From there, we used these methods for medical imaging applications such as the classification of field-of-view in MRI, and the segmentation of the kidney in 3D ultrasound images across two populations of patients. This last task required the development of a new transfer learning method based on the modification of the source network by adding new geometric and intensity transformation layers.Finally this thesis loops back to older computer vision methods, and we propose a new segmentation algorithm combining template deformation and deep learning. We show how to use a neural network to predict global and local transformations without requiring the ground-truth of these transformations. The method is validated on the task of kidney segmentation in 3D US images
Gozzard, Charles. "Optimisation of cementation, bone graft preparation, stability and load transfer in primary and revision hip arthroplasty." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430174.
Повний текст джерелаSamson, Rebecca Sara. "Optimisation of quantitative magnetisation transfer (QMT) MRI to study restricted protons in the living human brain." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1446083/.
Повний текст джерелаMarck, Gilles. "Optimisation topologique des transferts de chaleur et de masse : application aux échangeurs de chaleur." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00794779.
Повний текст джерелаKadem, Karim. "Modélisation et optimisation d’un coupleur magnétique pour la recharge par induction dynamique des véhicules électriques." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST032.
Повний текст джерелаThis thesis is carried out in collaboration between the GeePs laboratory and the VEDECOM institute. The cost, volume and weight of electrochemical batteries still represent a major obstacle to the deployment of electric vehicles (EVs). One of the solutions being considered to extend the range of EVs without excessively increasing the capacity of the batteries, is to use contactless electrical energy transfer systems to power them while they are on the move. This thesis focuses on one of these techniques which is the resonant inductive energy transfer. The problems associated with this mode of energy transfer are mainly related to energy efficiency, the size constrained due to the need for integration into the vehicle and the road as well as compliance with electromagnetic emissionstandards. The efficiency is directly linked to the coupling of the two coils (magnetic coupler). A comparison of the coupling coefficients for different coupler geometries and different misalignment configurations is the subject of the first part of this work. In the second part, an approach based on equivalent sources is suggested for the analytical pre-dimensioning of shielding plate intended to limit the magnetic emissions in and outside the vehicle. In the last axis of the thesis, the study is dedicated to techniques for detecting the presence of the vehicle and the sequencing of the different ground coils. A conclusion giving an assessment of the work and perspectives that open up from this work, close this manuscript
Pocaznoi, Diana. "Optimisation d'anodes microbiennes à partir de lixiviat de sol pour la conception de piles à combustible microbiennes." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0053/document.
Повний текст джерелаMicrobial fuel cells (MFC) are devices capable to convert chemical energy from organic fuels directly into electrical energy. In these cells, the fuel oxidation is provided by micro-organisms known as "electro-active"; these microorganism form biofilms on the surface of the anode and act as a catalyst for electrochemical reactions. The aim of this work was the optimisation of microbial anodes formed from bacterial flora contained in garden soils. The chronoamperometric experiments performed in a three-electrode system showed for the very first time in these systems that current densities of 66 A/m2 could be obtained by forming microbial anodes on ultra-microelectrodes. On electrode of normal size, the development of a new technique (delayed polarisation) for designing microbial biofilms produced current densities of 9.4 A/m2 after 3 days of polarisation, while the conventional protocol asked a few weeks for obtaining 6 to 8 A/m2. The study of different electrode materials indicated that stainless steel allowed reaching current densities up to 21 A/m2, which makes it a suitable candidate for designing electro-active biofilms. Indeed, the carbon electrodes provided up to 34.4 A/m2, even 50 A/m2 in anaerobic conditions, but the electrodes benefited of a three-dimensional structure contrasting the stainless steel electrode. The use of optimised microbial anodes in MFCs insured the production of 6 W/m2. In addition, the development of a new prototype containing a removable cathode allowed extending the lifetime of the initial MFC from 2 weeks to over 2 months
Collomb, Jean. "Optimisation du processus de dimensionnement thermomécanique de Moule Autonome à Transfert Thermique Efficient pour transformation rapide des matériaux composites à renforts continus." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAA019/document.
Повний текст джерелаThe issue of MATTE project is to propose an innovative process using perfectly controlled technologies for the production of structural composites high speed high performance with continuous fibers and thermoplastic resins (composites TPFC) or thermoset. This system is one of the techniques known as Heat & Cool, well known in the field of plastic injection. The aim of this technology is to extend these techniques to the field of structural composites. Compared to existing resources, this process will integrate in production: new monitoring functions, reduce energy consumption by about 80%, peripheral investments by 30% and to pursue a complete cycle time of less than 3 minutes. The similar method in the existing composite is the RTM, however, it is high energy consumption technology and do not allow high production rate. It is therefore the reference to quantify the performance of the MATTE technology
Essafi, Mohamed. "Conception et optimisation d'allocation de ressources dans les lignes d'usinage reconfigurables." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2010. http://tel.archives-ouvertes.fr/tel-00669980.
Повний текст джерелаYala, Omar. "Optimisation des colonnes HIDiC, intégrant une mousse métallique, basée sur une étude théorique et expérimentale des transferts thermiques." Thesis, Toulouse, INPT, 2017. http://www.theses.fr/2017INPT0106.
Повний текст джерелаDistillation is the most applied separation technology. Its major drawback is the low thermodynamic efficiency (typically around 10 %). In response to environmental issues that concern energy consumption of distillation column, HIDiC (heat integrated distillation column) which combines advantages of vapor recompression and diabatic operation is expected to have a large impact on energy saving. The mixtures with close boiling point are confirmed to be the best candidates for HIDiC. In fact, in this configuration the rectifying section and the stripping section are separated. Heat is transferred inside the distillation column from the rectifying to the stripping section, because the operating pressure (and thus the temperature) of the rectifying section is increased by means of the compressor. First, a novel technology of heat and mass transfer between rectifying column and stripping column is characterized and validated on an experimental pilot. A concentric HIDiC which contains metal foam packing is designed. Compared to the Raschig Super-Ring results, the heat transfer in this structured packing is more efficient, with a gain up to 102 %. The obtained thermal conductance UA (W.K-1) of the innovative column packing is 1285 W.K-1. This confirms the purpose of open cell metal foams use in HIDiC as a heat transfer technology. Secondly, the aim of this study is to optimize the HIDiC sensitive parameters so as to minimize the Total Annual Cost (TAC). For this, a HIDiC simulation model is developed by using commercial software ProSim Plus™®. GA (Genetic Algorithm) is used to find the optimal HIDiC configuration where variables are optimized without initialization. Binary (Benzene/Toluene) separation case is examined for the evaluation of the proposed method. As a result, 7.4 % and 13.9 % TAC reductions are realized in comparison with the reported solutions in previous works. Binary (Cyclohexane/n-Heptane) is studied to evaluate the physical feasibility of heat transfer between rectifying and stripping column by the experimental thermal conductance (UA experimental [W.K-1]) of the innovative column packing
Couraud, Benoît. "Optimisation des transferts d'énergie pour les systèmes connectés : application aux systèmes RFID communiquant en champ proche à très haut débit." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0572/document.
Повний текст джерелаThe research work presented in this thesis provides solutions to help industrials to better design RFID readers and RFID tags that implement VHBR (Very High Bit Rate) protocols. Indeed, VHBR technology has a large drawback on the functionning of RFID tags as it lowers the energy available to supply the tag. First, this research work focuses on RFID reader design, and especially matching networks design. After describing a new way of assessing power transfer in Radio Frequency systems, it is shown that T matching networks as thoses proposed in ISO/IEC 10373-6 give the best results in terms of power transfer and signal integrity. Thus, a design method is proposed to correctly choose the three T matching network components that will optimize the power transfer and still meet the signal integrity requirements.Second, this thesis will focus on the design of RFID tags, by describing a new tag's antenna design method that optimize the energy harvested by the antenna and meanwhile reduce the power reflections between the antenna and the tag's chip. This design method is based on new explicit formula that compute a rectangular planar antenna inductance as a function of its geometric characteristics. This method showed very accurate results, and can become an interesting tool for industrials to speed up and optimize their antenna design procedure.Finally, a platform that measures RFID chip's impedance in every state of the chip has been designed, even during load modulation communication. The accuracy of this tool and its importance in order to achieve a good antenna design confer it a great usefulness
Odlander, Paulina. "Optimisation and Validation of PCR Method for HLA Gene Expression to Enable PCR System Transfer and Master Mix Change." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-171826.
Повний текст джерелаAbou, Daher Mahmoud. "Réalisation et optimisation de transistors HEMT GaN forte puissance et haute fréquence par technologie de transfert de couches sur substrat hôte." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30046.
Повний текст джерелаWireless telecommunication market largely benefits from new nitride technologies, which reach outstanding performance compared with traditional technologies. Current research is opening up many new strategies and alternative solutions to address simultaneously antagonist considerations such as cost, performances and/or reliability. Most AlGaN / GaN HEMTs are fabricated on a low cost, highly resistive silicon substrate or on a much more expensive and supply sensitive SiC substrate. However, the electrical performance constraints required when these technologies are integrating into radar systems, satellites and in telecommunications systems make them dependent to the operating temperature parameter, mainly linked to the high power dissipation during static/dynamic energy transfer. Indeed, these components are capable of generating high power densities in the microwave range. However, the operating frequency increase leads an increase of the power dissipation, generating the self-heating phenomenon which influences the devices performance (ID,max,ft,fmax...). In this context, several solutions were already proposed in the literature (use of composite substrates, passivation of devices, etc.). Furthermore, the layer transfer technology to report HEMTs from growth substrate onto a host substrate with a good thermal conductivity (such as diamond substrate) is a promising solution, still poorly detailed to date. The objective of this thesis work is to improve the heat dissipation and thus the performance and reliability of high-frequency HEMT transistors by using a layer transfer technology. AlGaN / GaN heterostructures are grown on a silicon substrate by MOCVD at CHREA. After the fabrication of HEMTs on a silicon substrate, AlGaN / GaN devices (for which the silicon substrate has been removed) are transferred onto a CVD diamond substrate. This transfer is obtained by thermocompression bonding of sputtered AlN layers on each surface to be assembled (backside of the transistors and diamond substrate). This transfer process has not damaged the functionality of the transistors with short gate length (Lg = 80 nm). The AlGaN/GaN HEMTs with a 2x35 µm development transferred onto diamond of feature a current ID,max = 710 mA.mm-1, a cutoff frequency ft of 85GHz and an oscillation frequency fmax of 144GHz. However, this transfer technique requires optimization phases (especially to reduce thickness and improve the crystalline quality and thermal conductivity of AlN layers) in order to reduce the thermal resistance of this adhesion layer and to limit the self-heating phenomenon noted at the end of this thesis work
Subramaniam, Vignaesh. "Topology Optimization of Conjugated Heat Transfer Devices : Experimental and Numerical investigation." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2018. http://www.theses.fr/2018MTLD0013/document.
Повний текст джерелаDesigning thermal devices that are more compact with less mass, less frictional losses and increased thermal efficiency is a key requirement for enhanced performances at a lower cost. The present PhD thesis investigates the potential and validity of topology optimization numerical method as a viable CFD tool to generate optimal thermal designs as compared to conventional approaches like shape and parametric optimization. The first part of the thesis presents an experimental investigation of topology optimized tree-like structures made of two materials. The topolgy optimization mathematical problem is formulated and implemented in OpenFOAM®. It is applied to the topolgy optimization problem of volume-to-point heat removal. Experimental thermal measurements are carried out, on the optimal structures, using infrared thermography in order to quantify their heat transfer performances and thus validate the performances of the optimal structures determined by the developed topology optimization code. The second part of the thesis presents an innovative bi-objective optimization technique for topology optimization of Conjugate Heat Transfer (CHT) systems under laminar flow regimes. For that purpose, an inequality constrained bi-objective topology optimization problem is developed mathematically and implemented inside the Finite Volume based OpenFOAM® solver. The objective function is formulated by linear combination of two objective functions for pressure drop reduction and heat transfer enhancement which is numerically a very challenging task due to a competition between the two objectives (minimization of pressure drop and maximization of recoverable thermal power). Non-intuitive Pareto-optimal designs were obtained, analyzed, discussed and justified with the help of various global and local numerical analysis methods. Additionally, a recent Lattice Boltzmann topology optimization problem form the literature was solved using the developed OpenFOAM® solver. The objective, in addition to the comparison of the optimal solutions, is also to initiate a case of reference for future studies in this field of research and innovation so as to be able to fully compare the optimal solutions obtained by different and different methods. solvers. Finally, the various experimental and numerical findings highlighted and illustrated in this PhD thesis, demonstrate the importance of the methodology and immense potential behind topology optimization method for designing efficient industrial thermal systems
Fertahi, Saïf ed-Dîn. "Simulation et optimisation des systèmes de production de l’eau chaude sanitaire solaire." Thesis, Pau, 2019. https://tel.archives-ouvertes.fr/tel-02528278.
Повний текст джерелаThe world market for solar water heaters (SWH) is in great expansion. In fact, SWHs have become a challenging alternative system to gas and electric heating devices, because of their low CO2 emissions and their explicit involvement in the reduction of the building’s electric bills. L’institut de recherche en énergie solaire et énergies nouvelles (IRESEN-Morocco) is actually providing the necessary funding support to promote research and development field of SWHs in Morocco. Hence, in February 2016, SOL’R SHEMSY project has been defined in order to design and commercialize the first SWH integrating Evacuated Tube Collectors (ETC) with heat pipes, under the constraints of being accessible to the Moroccan public users. For the time being, several technologies of solar collectors with different brands are commercialized in Morocco such as flat plat collectors (FPC) and Evacuated Tube Collectors (ETC), besides to thermosyphon and forced circulation SWHs to convert solar energy to thermal energy, in order to produce hot water with the temperature required in several applications (individual, collective, industrial and the tertiary applications). However, a serious challenge of adjustment, integration and technology transfer should be considered before importing SWHs with ETC into the Moroccan market from supplier countries such as China, Spain, Germany and Turkey described as the leading manufacturer of SWH in the world. Indeed, the imported SWHs in Morocco presented thermo-mechanical failure modes after a short period of use such as the limestone deposited inside the storage tanks, corrosion and cracking of their inner shell... Taking into account the challenge of adjustment, integration and technology transfer of SWHs in Morocco is necessary, because the conditions of use differ from one country to another in terms of climatic conditions, which can be summarized in solar radiations, ambient temperature, wind velocity and the percentage of humidity in the air. In addition, the consumer's random consumption profile usually affects the thermal efficiency of the collector field and the overall solar fraction of SWHs.The main aim of this thesis is to carry out numerical simulations and optimizations of SWHs taking into account the techno-economic context of Morocco and its intrinsic weather conditions. Two simulation approaches were used to achieve this purpose. The first approach was based on unsteady Computational Fluid Dynamics (CFD) numerical simulation in order to enhance the efficiency of the heat pipes integrated inside ETCs and to increase the thermal stratification indicators of horizontal thermal storage tanks with submerged heat pipes. Finally, improve the storage tank’s structure using thermo-mechanical coupling simulations. The second approach is based on dynamic simulations, which have been performed to assess and optimize the energy performance of a collective hot water process intended to produce domestic hot water (DHW) under the climatic conditions of Fez city located in Morocco. Indeed, several parameters have been considered, in particular the effect of the storage tank volume, the brands of collectors and their technology from different manufacturers, the connection between the solar panel and the overall surface of the ETC and FPC which constitute the collector field etc
Gbaha, Prosper. "Etude et optimisation des échanges thermiques et des performances des capteurs solaires plans à deux veines d'air." Valenciennes, 1989. https://ged.uphf.fr/nuxeo/site/esupversions/199c6e47-ffeb-4b05-864d-30770aff5a49.
Повний текст джерелаBruckner, Michael. "Biofluid Mechanics Of Embryo Transfer." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10159.
Повний текст джерелаThis thesis focuses on the study of the hydrodynamic behavior of an embryo during the transfer process following the in vitro fertilization. Worldwide, one in six couples experiences infertility problems. Today, 5 millions babies are born from an in-vitro fertilization since the first one in 1978. In 2009, 1.5 millions Assisted Reproductive Technology cycles have been started, resulting in 350 000 births. The total number of cycles per year is constantly increasing (from 5 to 10 %), and the number of ART cycles is believed to reach 4 millions per year in 2020. Although the fertilization step is now fairly mastered with a 80% success rate, the final stage consisting in the embryo transfer into the uterine cavity remains a critical step, since only 25% of the cycles lead to a live birth. Even though every cycle is expensive, no specific, optimized and operator-independent protocol has been developed yet. In this thesis, we first demonstrate the interest and the feasibility of a bio-engineering approach. Indeed, although the issue of the transfer depends on numerous chemical and physiological factors, this crucial step can also be studied from a fluid mechanical point of view. This step can be divided in several sub-steps : introduction of the catheter in the intra-uterine cavity, injection of the medium fluid containing one or several embryos, and the withdrawal of the catheter. One can identify several important parameters such as fluids viscosity, injections speeds, catheter withdrawal speed, catheter loading scheme and the geometries of the uterine cavity and the catheter. In a second part, we focus on the fluid ow patterns inside the uterine cavity during the injection. The influence of the system parameters is studied thanks to a computational solving of the Navier-Stokes equations in an idealized three-dimensional uterine cavity. A study of the potential trajectories of the embryos is also conducted and confronted against the location of optimal implantation zones but also risky zones. As the outcome of these computations, we are able to propose recommendations for physicians practicing embryo transfers. In the last part of the thesis, we discuss numerical methods for the fluid{structure interaction study of embryo transfer. The embryo is indeed submitted to potentially destructive stress constraints at injection time that we are not capable of defining precisely at the scale of the uterine cavity. With the aim of developing a mechanical model for the blastocyst to determine system parameters minimizing the constraints, we present the implementation of two Eulerian numerical methods. The first one is a fluid-structure level set method in a finite volume code benefiting from an automatic mesh refinement feature. The second one addresses a phase field method based on a Discontinuous Galerkin finite element formalism
Frasnedo, Sophie. "Optimisation des lois de commande d’un imageur sur critère optronique. Application à un imageur à deux étages de stabilisation." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC079/document.
Повний текст джерелаThe presented work on the Line of Sight stabilization of an optronic device meets the heightened demands regarding stabilization performances that come with the reduction of the time allowed to controller tuning.It includes the intrinsinc improvement of the system stabilization. The proposed solution features a double stabilization stage built from a single stabilization stage existing system. The new architecture is specified and the new components are chosen among the existing technology and experimentally characterized. A complete double stabilization stage model is then proposed.The simplification of the controller tuning process is another goal. The designed cost function F includes a high-level optronic criterion, the Modulation Transfer Function (that quantifies the level of blur broughtinto the image by the residual motion of the platform) instead of the usual low-level and potentially conservative criterion.The function F is costly to evaluate. In order to tune the controller parameters within industrial time constraints, a Bayesian algorithm, adapted to optimization with a reduced budget of evaluations, is implemented.Controllers of both stabilization stages are simultaneously tuned thanks to the previously developped system model
Stehlík, Jan. "Minimální mzda v ČR po roce 1990 a její užití jako suplementu sociálních transferů." Master's thesis, Vysoká škola ekonomická v Praze, 2015. http://www.nusl.cz/ntk/nusl-205958.
Повний текст джерелаHassan, Hamdy Abo Ali. "Etude et optimisation des transferts de chaleur en injection moulage : analyse de leur influence sur les propriétés finales." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13956.
Повний текст джерелаPlastics are typically polymers of high molecular weight, and may contain other substances to improve performance and/or reduce costs. Plastic industry is one of the world?s fastest growing industries; almost every product that is used in daily life involves the usage of plastic. There are different methods for polymer processing (thermoforming, blow molding, compression molding of polymers, transfer molding of polymers, extrusion of polymers, injection molding of polymers, etc.) which differ by the method of fabrications, the used materials, the quality of the product and the form of the final product. Demand for injection molded parts continues to increase every year because plastic injection molding process is well known as the most efficient manufacturing techniques for economically producing precise plastic parts and complex geometry at low cost and a large quantity. The plastic injection molding process is a cyclic process where polymer is injected into a mold cavity, and solidifies to form a plastic part. There are three significant stages in each cycle. The first stage is filling the cavity with hot polymer melt at high injection pressure and temperature (filling and post-filling stage). It is followed by cooling the injected polymer material until the material is completely solidified (cooling stage), finally the solidified part is ejected (ejection stage)
Mehra, Bineet. "Design and optimisation of innovative electronic cooling heat sinks with enhanced thermal performances using numerical and experimental methods." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2019. http://www.theses.fr/2019MTLD0005/document.
Повний текст джерелаThis doctoral thesis focuses on mechanisms of heat transfer enhancement in plate and fin heat sink geometries. First part of the thesis is dedicated to study an academic configuration using numerical simulations to achieve an improvement in conjugate heat transfer by modifying only the geometrical shape (through punching) of the conductive plane fins. An in-depth local analysis of the flow and thermal fields was carried out with the local synergy principle, velocity and thermal gradients, to understand the effect of geometric modifications. This thesis also presents the development of heat sinks with increased thermo-hydraulic performance for on-board electronic box cooling applications. The intensification of the heat transfer is obtained by the generation of secondary flows which cause an intensive mixing of fluid and reduces the thermal resistance to the wall by disrupting the development of the thermal boundary layer. Different heat sink geometries with two types of secondary flow generators : delta winglet pair and protrusions were numerically studied using RANS approach. The thermo-hydraulic performances of the geometries equipped with vortex generators were compared with that of a smooth reference heat sink. The prototypes were also manufactured and tested on an experimental bench specifically designed to perform global performance measurements in terms of thermal power and pressure drops. Experimental and numerical results were compared to qualify the simulations performed. Subsequently, an optimization study using Taguchi factorial analysis was used to optimize the geometrical parameters of the chosen dissipaters. Two objective functions were considered : maximization of either iso-pumping power performance criteria (PEC) or average wall temperature of the dissipaters compared to the reference case. The global thermo-hydraulic performance analysis of the studied geometries was completed by a qualitative analysis of local flow and thermal fields, in particular with the local field synergy principle
Van, der Walt Stefan. "The design and optimisation of a bubble pump for an aqua-ammonia diffusion absorption heat pump / Stefan van der Walt." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9231.
Повний текст джерелаThesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.
Adami, Salah-Eddine. "Optimisation de la récupération d'énergie dans les applications de rectenna." Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00967525.
Повний текст джерелаTahiri, Ayoub. "Optimisation des flux dans les réseaux de transport pour les systèmes dynamiques étendus : cas des systèmes hydrographiques." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0039/document.
Повний текст джерелаOptimal allocation of the resource, in a large scale system, consists in distributing it and delivering it to the right places, at the right time and in the right quantity. The transported flows are characterized by nonlinearities and are subject to delays during their transfer, but also to significant deformations when the resource is a fluid. In this work, we propose to take into account, all these constraints in the modeling of these systems, for an optimal management of fluid transport. The system is modeled by an expanded flow network in order to represent the evolution of the resource over time and to integrate the delays that are inherent in flow transfers. In order to introduce the flow dynamics of open-channel flows into the graph, we define distribution nodes allowing to model the flow propagation phenomena. The water allocation objectives are represented by costs on the network’s arcs. The optimal allocation of the resource is obtained by the search for the minimal cost flow on the network. To this end, an optimization algorithm taking into account the additional constraints resulting from the distribution nodes is proposed. The methods and algorithms developed, are applied to the case of hydrographic systems and to the water resources management problem. The latter has become crucial due to the negative effects of anthropisation of natural areas, climate change and increasing needs. Water allocation consists in sharing the water resource between different users, according to a combination of objectives and priorities. The allocation of the water resource is carried out in three main steps: the diagnosis of the state of the available resource on the hydrographic system at the initial time step, including the forecast of its evolution over the management horizon; the determination of operations to be carried out on the hydraulic system to allocate the resource according to the constraints and objectives; the monitoring of the measured data in order to provide reconstructed indicators of the system’s state. The performances of the proposed approach are evaluated on various hydrographic systems, subjected to multiple hydrological regimes
Bardolle, Frédéric. "Modélisation des hydrosystèmes par approche systémique." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAH006/document.
Повний текст джерелаIn the light of current knowledge, hydrosystems cannot be modelled as a whole since underlying physical principles are not totally understood. Systemic models simplify hydrosystem representation by considering only water flows. The aim of this work is to provide a systemic modelling tool giving information about hydrosystem physical behavior while being simple and parsimonious. This model, called HMSA (for Hydrosystem Modelling with a Systemic Approach) is based on parametric transfer functions chose for their low parametrization, their general nature and their physical interpretation. It is versatile, since its architecture is modular, and the user can choose the number of inputs, outputs and transfer functions. Inversion is done with recent machine learning heuristic family, based on swarm intelligence called PSO (Particle Swarm Optimization). The model and its inversion algorithms are tested first with a textbook case, and then with a real-world case
Ben, Chaabane Afif. "Optimisation des échanges thermiques entre futs de cylindres d'un moteur à combustion interne et le liquide de refroidissement." Paris 6, 1986. http://www.theses.fr/1986PA066324.
Повний текст джерелаMchinda, Samira. "Optimisation théorique et expérimentale de la technique IRM du transfert d’aimantation inhomogène pour l’imagerie de la myéline : application à la sclérose en plaques." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0378.
Повний текст джерелаThe ihMT technique selectively isolates the signal associated with certain macromolecules by exploiting the dipolar coupling processes to which they are subjected, on the basis of their lifetime characterized by the dipolar relaxation time, T1D. The relatively long T1D values in myelinated structures provide selective images of myelin. The objective of this thesis is the development of ihMT 3D MRI sequences optimized in terms of sensitivity to myelin,which is an essential membrane for nerve impulse conduction, for clinical application. To achieve it, we first developed physical models (numerical calculations with Matlab) based on the theory of saturation of spins in solids, which describe the evolution of the ihMT signal over time as a function of tissue parameters and for realistic parameters of clinical MRI sequences.. Using this theoretical model, we then optimized a 3D ihMT sequence on a 1.5T MRI scanner. The optimal parameters resulted in a high-resolution protocol of the whole brain, with increased sensitivity to myelinated structures. Then we extended this optimization work at 3T. Optimal parameters at 3T also resulted in a high-resolution protocol for the whole brain, with a trade-off between high sensitivity to myelinated structures and reduced sensitivity to B1 field inhomogeneities. In order to validate the ihMT technique as a myelin biomarker, To evaluate the clinical potential of the ihMT technique as a myelin biomarker, we have applied the optimized sequence in a study of a cohort of patients with relapsing-remitting multiple sclerosis (RR), in which we sought to identify and monitor the processes of spontaneous demyelination and remyelination over time