Dissertations / Theses on the topic 'Non-homogeneous'
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Witt, James David Samuel. "Superconductivity and non-homogeneous magnetism." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610601.
Full textBen, Mahjoub Otman. "Non-local dynamics and intermittency in non-homogeneous flows." Doctoral thesis, Universitat Politècnica de Catalunya, 2000. http://hdl.handle.net/10803/6572.
Full textLa tesi analitza les dinàmiques no locals i la intermitència en fluids no homogenis i no isotròpics tant en experiments de laboratori com en dades geogràfiques. Després de l'estudi sobre els models que descriuen la intermitència en fluids homogenis i isotròpics, presentem un model per fluids no homogenis i no isotropics. El model es basa en l'anàlisi de la jerarquia de transmissió d'energia. S'utilitza la tècnica de la Extended Self Similarity amb l'objectiu d'estudiar l'escala de lleis de les funcions estructurals de velocitat. Els resultats experimentals de tres tipus de fluids que s'han comparat amb el model per fluids no homogenis i no isotròpics són els següents: turbulència generada per un cilindre en un canal de vent i turbulència generada per una reixa i per un jet en un canal d'aigua. S'analitza la turbulència geogràfica del Delta de l'Ebre i del Knebel Vig i els resultats són comparats amb els del model anteriorment esmentat. La contribució principal és el descobriment d'un paràmetre aparentment relacionat amb la jerarquia de transmissió d'energia en el rang inercial que juga un paper clau en la comprensió de les dinàmiques dels fluids no homogenis.
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The thesis analyze the non-local dynamics and intermittency in non-homogeneous and non-isotropic flows both in the laboratory experiments and geophysical data. After a review on models describing intermittency in homogeneous and isotropic flows, a different model for non-homogeneous and non-isotropic flows is introduced. A model is based on the analysis of the energy transfer hierarchy. The technique of Extended Self Similarity is used to study the scaling laws of the velocity structure functions. Experimental results of three type of flows cylinder wake turbulence in wind tunnel, grid and jet turbulence in water channel are presented and compared with the model. The geophysical turbulence in the Ebro Delta and Knebel Vig are analyzed and the results are compared with the model. The important contribution is the discovery of a new apparently parameter related to the energy transfer hierarchy in the inertial range which plays a key role in the understanding of the dynamics of the non-homogeneous flows.
Alnuaimi, Nasser Abdullah. "Modeling ultrasonic transducer in homogeneous and non-homogeneous media using DPSM method." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280583.
Full textLa, Vecchia Miriam. "Bacterial chemotaxis in non-homogeneous shear flow." Thesis, KTH, Mekanik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-36075.
Full textLee, Siew-Eang. "Transmission of sound through non-homogeneous walls." Thesis, Heriot-Watt University, 1985. http://hdl.handle.net/10399/1656.
Full textTsamis, Alexandros 1976. "Digital graft : towards a non-homogeneous materiality." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28810.
Full textIncludes bibliographical references (leaves 104-110).
(cont.) and form development. Through this approach, space can be perceived not as distributed geometries, but rather as a composite graft responding locally to flows of programmatic and environmental parameters.
Digital methodologies have radically shifted our conception of the design process, as well as our understanding of geometry in terms of flexible relationships instead of finite positions in space. However, the material tectonic that digital means imply has not yet been explored on the basis of the new possibilities disclosed by these very same tools. Tectonic investigations have almost exclusively focused on construction techniques and primarily on the optimisation of methods that preceded the appearance of digital tools. I would argue, that computer generated architecture might imply a new understanding of matter and mass. So far, the materialization of formal expressions instigated by such processes are primarily based on techniques of assembly, which do not negotiate the advanced levels of material complexity that the tools put forward. This thesis lies on the premise of investigating modes to address an emergent rather than imposed materiality of distributions, instigated by computer-generated processes. Methodologically, this thesis has a twofold task. The former is to interrogate an alternate prism of construction history, which does not shed emphasis on geometry, but rather on mass and matter, paraphrasing Michel Serres. The atter task is to launch design experiments that respond to an alternate, emerging perception of material densities, constellations and coagulations. Through a series of digital case studies it becomes both a "theoretical" and "technical" probe of a materiality with local differences exploring non-homogeneous ways of distributing matter in space. Three material strategies--thread, component and substance--will be presented in an attempt to address modes of interrogating a reciprocal relationship between material
by Alexandros Tsamis.
S.M.
Qiu, Hongtao. "Natural convection in a non-homogeneous enclosure." Ann Arbor, Mich. : ProQuest, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3303953.
Full textTitle from PDF title page (viewed Mar. 16, 2009). Source: Dissertation Abstracts International, Volume: 69-03, Section: B, page: 1917. Adviser: Jose L. Lage. Includes bibliographical references.
Redd, Preston T. "Market Dynamics with Non-Homogeneous Poisson Processes." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3630.
Full textLegg, Matthew W. "Non-Gaussian and non-homogeneous Poisson models of snapping shrimp noise." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/839.
Full textForcillo, Nicolò. "Free Boundary Regularity of Some Non-Homogeneous Problems." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16392/.
Full textKeilson, Julian, and Les D. Servi. "Networks of Non-homogeneous M/G/oo Systems." Massachusetts Institute of Technology, Operations Research Center, 1990. http://hdl.handle.net/1721.1/5188.
Full textWilson, Lynda M. Z. "Controllability of Non-Newtonian fluids under homogeneous flows." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Sep%5FWilson%5FLynda.pdf.
Full textThesis Advisor(s): Zhou, Hong. "September 2007." Description based on title screen as viewed on October 25, 2007. Includes bibliographical references (p. 47). Also available in print.
Manoubi, Maha. "Combustion Characteristics for Non-homogeneous Segregated H2-Air Mixtures." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32272.
Full textParent, Paul-Eugène. "Formal and non-formal homogeneous spaces of small rank." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/9873.
Full textHubbard, Rebecca Allana. "Modeling a non-homogeneous Markov process via time transformation /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/9607.
Full textKarkutla, Raja K. "Agent Based and Stochastic Simulations for Non-homogeneous Systems." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1271708137.
Full textLi, Shenghao. "Non-homogeneous Boundary Value Problems for Boussinesq-type Equations." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1468512590.
Full textRenner, Andrew. "Four-Dimensional Non-Reductive Homogeneous Manifolds with Neutral Metrics." DigitalCommons@USU, 2004. https://digitalcommons.usu.edu/etd/7149.
Full textLawson, Brodie Alexander James. "Cell migration and proliferation on homogeneous and non-homogeneous domains : modelling on the scale of individuals and populations." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/61066/1/Brodie_Lawson_Thesis.pdf.
Full textLu, Yi. "Periodicity and ruin probabilities for compound non-homogeneous Poisson processes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ59274.pdf.
Full textSwift, George Peter. "Propagation of terahertz radiation in non-homogeneous materials and structures." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2258/.
Full textPINHO, ADRIANO FERNANDES. "EFFECTS AND APPLICATIONS OF NON-HOMOGENEOUS STRAINS IN BRAGG GRATINGS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7099@1.
Full textRedes de Bragg em fibras ópticas (RBF) são formadas por modulações periódicas introduzidas no índice de refração do núcleo de fibras ópticas. Estes componentes comportam-se como filtros espectrais de banda passante, ou seja, quando iluminados por um sinal óptico de banda larga, refletem apenas uma fina fatia espectral de luz, cujo centro, o comprimento de onda de Bragg, é proporcional ao período espacial da modulação no índice de refração. As RBF têm encontrado aplicações importantes no sensoriamento das mais diversas grandezas, sendo hoje utilizadas em sistemas de monitoramento para vários segmentos industriais, tais como os setores de petróleo e gás, construção civil e aeroespacial, que, estima-se, respondem em conjunto por cerca de 70% destas aplicações. Em diversas situações o sensoriamento com RBF baseia-se em medidas indiretas da grandeza de interesse, sendo empregados mecanismos de transdução que transformam variações do mensurando em deformações na fibra óptica. Nestes casos, um problema que deve ser tratado com atenção é o acoplamento entre temperatura e deformação, uma vez que as RBF são sensíveis a estas duas variáveis. Não raro, a alternativa é utilizar simultaneamente duas RBF para obter-se a compensação de temperatura na medida de deformação. Este trabalho apresenta um estudo sobre deformações não homogêneas em redes de Bragg e discute aplicações de duas técnicas que podem ser utilizadas como alternativas para eliminar o efeito da temperatura no sensoriamento de deformação com apenas uma RBF. A primeira delas explora a birrefringência óptica induzida na RBF por carregamentos transversais à fibra óptica. A segunda baseia-se nos efeitos sobre o espectro refletido pela rede de Bragg quando submetida a um campo de deformações longitudinais não uniformes ao longo da direção axial da fibra óptica. No trabalho são apresentados protótipos e dispositivos que exploram tais técnicas para a medida simultânea de pressão e temperatura. Esses protótipos foram projetados com auxílio de ferramentas CAD e modelados utilizando-se o método de elementos finitos em conjunto com a teoria de modos acoplados da Rede de Bragg. As previsões obtidas utilizando-se estes modelos mostraram-se bastante próximas dos resultados das implementações experimentais dos protótipos, indicando que a metodologia de modelagem desenvolvida pode ser aplicada nos projetos de transdutores baseados nas duas técnicas estudadas.
Fiber Bragg gratings (FBG) are modulations in the effective refractive index of optical fibers, introduced in a small length along the fiber core. Such components operate as narrow band reflective filters, that is, when illuminated by a broad-band light source, they reflect a narrow spectral band centered at a specific wavelength, the Bragg wavelength. This wavelength is proportional to the spatial period of the refractive index modulation. Fiber Bragg gratings have find an increasing number of applications as sensors for different quantities, and today are being employed as part of permanent, real time monitoring systems in various industrial segments. The oil and gas sector, together with civil infrastructure and aeronautics and aerospace, account for almost 70% of this applications. In a number of situations, FBG sensing is based on indirect measurements of the quantity being monitored, and a transduction mechanism is employed to transform changes in the measured quantity in strain sensed by the optical fiber. Since the FBG is sensitive to strain and temperature, proper temperature compensation is always necessary. Usually, a second grating is employed to simultaneously measure temperature and strain, performing the required compensation. This thesis presents a study on effects due to non- homogeneous strains in the Bragg grating and discusses application of two different techniques, based on these effects, to allow temperature compensated strain measurement using a single FBG. The first technique explores strain induced optical birefringence when the fiber is loaded transversely. The second technique is based on changes in the spectral shape of the light signal reflected by the grating when subjected to non homogeneous axial strain fields. Prototypes of pressure and temperature transducers based on these techniques have been developed. These prototypes have been designed by employing CAD techniques and modeled using the finite element method in conjunction with the theory of coupled modes for fiber Bragg gratings. Comparisons between results provided by theoretical models and experimental realizations of the prototypes are very close, demonstrating that the developed approach can be applied to design transducers based on the discussed techniques. Results obtained with the proposed pressure and temperature sensors are also encouraging indicating that the two techniques are suitable for industrial applications.
Kadyrov, Shirali. "Entropy and Escape of Mass in Non-Compact Homogeneous Spaces." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1272027404.
Full textFalconer, Steven. "Subdiffusive transport in non-homogeneous media and nonlinear fractional equations." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/subdiffusive-transport-in-nonhomogeneous-media-and-nonlinear-fractional-equations(a695fe6e-02d2-4fa1-b90b-6a57505973fc).html.
Full textSegarra, Almela Candela. "Homogeneous catalysts for green processes and non-conventional NHC-based complexes." Doctoral thesis, Universitat Jaume I, 2014. http://hdl.handle.net/10803/669080.
Full textHewitt, Scott. "Notational approaches for composing and directing a non-homogeneous laptop orchestra." Thesis, University of Huddersfield, 2014. http://eprints.hud.ac.uk/id/eprint/23317/.
Full textBuenger, Carl D. Buenger. "Quantitative Non-Divergence, Effective Mixing, and Random Walks on Homogeneous Spaces." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1462800914.
Full textCardon, Sandra Jean. "Obtaining eddy fluxes for a non-homogeneous environment using wavelet cospectra." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1320974421&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full textKoroma, Samuel Gerald. "Vibration of beams on non-linear and non-homogeneous elastic foundations with applications to railway tracks." Thesis, University of Nottingham, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.756108.
Full textGarcia, Domingo Josep Lluís. "Real analysis in non-euclidean spaces: trees and spaces of homogeneous type." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/2124.
Full textEl contenido de esta tesis se enmarca dentro del Análisis Real. En particular, trata del estudio de ciertos problemas de la teoría de pesos, (una referencia clásica sobre esta teoría es el libro de J. García-Cuerva y J.L. Rubio de Francia [GR]). Nosotros consideramos, por este orden, tres problemas clásicos diferentes, que abarcan buena parte de la teoría de pesos:
(i) Estudio de las inclusiones para espacios con pesos y acotación de operadores integrales entre estos espacios.
(ii) Estudio de propiedades funcionales de espacios con pesos asociados a una reordenada decreciente de funciones.
(iii) Estudio de la acotación de operadores maximales asociados a regiones de aproximación entre espacios con pesos.
Todos estos problemas han sido tratados extensamente en la literatura. Nuestro enfoque ha sido el de extender estos resultados a espacios con la mínima estructura necesaria. Concretamente, hemos trabajado respectivamente en cada capítulo en los siguientes contextos:
(i) Espacios de medida arbitrarios.
(ii) Árboles.
(iii) Espacios de tipo homogéneo.
Puesto que un árbol puede ser a su vez un espacio de medida, o puesto que su frontera puede ser un espacio de tipo homogéneo, algunos resultados para espacios de medida y espacios de tipo homogéneo han sido aplicados a los árboles (véanse los capítulos primero y tercero). En cambio, en el capítulo segundo trabajamos exclusivamente en árboles.
Los espacios donde hemos desarrollado nuestra teoría no poseen, en general, ningún tipo de estructura algebraica. Por tanto, todos los resultados persiguen un objetivo común: la extensión de la teoría de pesos a espacios no euclidianos.
Hayakawa, Yoshikazu, and Tomohiko Jimbo. "Transformability from discrete-time periodic non-homogeneous systems to time-invariant ones." IEEE, 2009. http://hdl.handle.net/2237/13935.
Full text文國輝 and Kwok-fai Man. "Elastic solution for rectangular and circular plates on non-homogeneous soil foundation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31208320.
Full textVan, Den Heever Emile. "Rheological model influence on pipe flow predictions for homogeneous non-Newtonian fluids." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1030.
Full textThe reliable prediction of pressure drop versus flow rate for non-Newtonian pipe flow is important in many industrial processes. In laminar flow scale up is straightforward, but transitional velocity and turbulent flow predictions remain a practical problem. Various theoretical models exist, but nothing in literature shows conclusively which of these is the most reliable and consistent, nor is it evident what effect the choice of rheological model has on the predictions. The aim of this work was to i) evaluate the influence of different rheological models when used in existing prediction techniques for non-Newtonian flow ii) characterise each material type using selected (commonly used) rheological models and iii) predict laminar, transitional and turbulent pipe flow characteristics for each material type using existing prediction techniques, for comparison with experimental results. Only time-independent, homogeneous, non-Newtonian fluids in pipe sizes from 13mm to 200mm were investigated. Rheological models and laminar flow predictions used only the power law, Bingham plastic, Herschel-Bulkley, Casson and Hallbom yield plastic models. The techniques used to predict transitional velocity were Ryan & Johnson, Metzner-Reed, Hedström intersection method, Slatter and Hallbom. For turbulent flow the Newtonian approximation, Dodge & Metzner, Wilson & Thomas, Slatter, Hallbom modified Wilson & Thomas and the Bowen correlation methods were used. The study documents the relevant theory and presents an assessment of the influence of rheology on pipe flow predictions, summarised in terms of the practical performance of the various rheological model/prediction method combinations for the different materials. In laminar flow at practical pseudo shear rates (8V/D; taken as 40s-1) the choice of rheological model does not significantly influence pressure drop predictions. For yield-pseudoplastic materials (eg. kaolin) the Hedström intersection and the Slatter Reynolds number method with Bingham plastic or Casson rheology predicted transitional velocity most accurately. For Bingham plastic materials (eg. bentonite) the best predictions were obtained using the Metzner & Reed Reynolds number with Bingham plastic rheology, although similar results were observed for this technique with all rheologies. The transitional velocity for pseudoplastic materials (eg. CMC) was best predicted by the Slatter and Metzner & Reed Reynolds number methods, using power law or Casson rheology. For turbulent flow of yield pseudoplastic materials the Slatter method using the Casson rheology gave the most accurate predictions overall. Turbulent flow of Bingham plastic materials was best predicted by the Slatter, Hallbom pseudo fluid Nikuradse and Dodge & Metzner methods, using Bingham plastic, Casson or yield plastic rheology. For pseudoplastic materials the Slatter and Wilson & Thomas methods were the most accurate, when used with yield plastic or power law rheology. Transitionalal velocity and turbulent flow predictions for materials with a yield stress vary significantly with rheological model. Laminar data should therefore be examined thoroughly and rheological models fitted with care. For pseudoplastic fluids there is little difference in predictions between the various techniques as long as power law rheology is used.
Zengeni, Brian Tonderai. "Bingham yield stress and Bingham plastic viscosity of homogeneous Non-Newtonian slurries." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2458.
Full textThis dissertation presents how material properties (solids densities, particle size distributions, particle shapes and concentration) of gold tailings slurries are related to their rheological parameters, which are yield stress and viscosity. In this particular case Bingham yield stresses and Bingham plastic viscosities. Predictive models were developed from analysing data in a slurry database to predict the Bingham yield stresses and Bingham plastic viscosities from their material properties. The overall goal of this study was to develop a validated set of mathematical models to predict Bingham yield stresses and Bingham plastic viscosities from their material properties. The interaction of the non-Newtonian material properties is very complex at varying mass solids concentrations. The evaluation of these interactions in terms of constitutive equations is almost impossible and the relationship between material properties, mass solids concentration and rheology can only be modelled in a statistical manner. The validity of each model is checked to ensure that predictions and interpretations are unbiased and efficient. This is done by comparing the resulting models to experimental data generated from test work. An in-depth analysis was conducted to see the interrelationship between the material properties and how they affect the yield stress and viscosity values.
Man, Kwok-fai. "Elastic solution for rectangular and circular plates on non-homogeneous soil foundation /." [Hong Kong : University of Hong Kong], 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12350679.
Full textKasperski, Michael William. "Multiple model estimation for linear stochastic hybrid systems with non-homogeneous transition probabilities." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101496.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 61-64).
This thesis investigates the field of stochastic hybrid estimation. A broad introduction to the framework surrounding estimation, filtering, and multiple model based systems is presented. More specifically, the often made assumption of a constant time-invariant mode transition probability matrix is relaxed. Recent work done in the area of non-Markov jump stochastic hybrid systems is explored, including semi- Markov systems, non-homogeneous transition probability matrices, and continuous-state-dependent mode transitions. Algorithms needed to develop linear multiple model based filters with non-homogeneous transition probabilities are detailed. Finally, a case study for the practical implementation of an extended Kalman filter in the application of attitude heading and reference systems is conducted.
by Michael William Kasperski.
S.M.
Pina, Patricia E. (Patricia Elena). "Cognitive and operational implications of non-homogeneous aircraft equipage for aviation system transformation." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42198.
Full text"August 2007."
Includes bibliographical references (leaves 85-87).
The air traffic management system is currently experiencing a significant transformation to provide better quality service and to match the increasing air traffic demand. This transformation requires airlines to retrofit their fleet. However, airlines implement new operating capabilities at different rates resulting in long transition periods in which aircraft with different equipage levels coexist in the same airspace. Mixed equipage environments can increase controller workload and task complexity, limit the operational benefits of new operating capabilities, and deteriorate the overall system performance. This study proposes a three dimensional approach to explore mixed equipage effects: (1) understand cognitive implications for controllers, (2) understand operational implications for users, and (3) understand system level implications. To further investigate mixed equipage effects and to illustrate the proposed approach, this study analyzed the implementation of reduced separation standards in the North Atlantic. An experimental analysis was conducted to study the integration of mixed separation standards. Results show significant human factor concerns. Controllers had higher error rates at very low mixed equipage levels. Results also suggest that a contributing causal factor may have been that participants employed inadequate system abstractions based on their current mental models. Airspace segregation based on equipage levels is recommended in the North Atlantic to alleviate controller cognitive limitations and ensure incentives for equipped aircraft. Segregation can facilitate the transition to reduced separation standards.
(cont.) A preliminary estimation of the operational benefits that segregation could offer to equipped aircraft in the North Atlantic was performed. We developed a simplified model of the jet stream and its operational cost impact and contrasted the results with a statistical analysis of actual North Atlantic flight times. It was found that the model made optimistic predictions of flight time reduction. Based on the statistical analysis, the incentive for equipped aircraft in a segregated environment in the North Atlantic was estimated by a gain of 4 minutes. This figure is a preliminary estimation and further analysis with larger data samples is required to validate it.
by Patricia E. Pina.
S.M.
Carbone, Giovanni Francesco Davide. "Comportement dynamique d'un dirigeable en écoulement non homogène." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2020. http://www.theses.fr/2020MTLD0009.
Full textThe objective of this thesis is to study the aerodynamics of an airship in unsteady and non-homogeneous flow conditions, describing its dynamics through simplified models and fast and efficient computationlal tools.Because of their « lightness », airships are more sensitive to air disturbances. This has a major impact on their controllability and consequently on the sizing of the control surfaces and the propulsion system.Aerodynamic phenomena related to the notion of added masses, which are observed during the relative accelerated motion phases of the airship, are an additional term to be taken into account for the evaluation of the overall aerodynamic stresses. They depend on the density of the fluid, the geometry of the body and the reference frame. Generally, these contributions are neglected in the investigation of « heavy » bodies such as airplanes, since their density is considerably higher that of air. On the contrary, for airships these terms are the same order of magnitude of their mass and their moment of inertia and therefore represent a fundamental aspect to be taken into account to correctly describe their dynamics.Our studies on added masses have been carried out through numerical simulations in potential and viscous flows. A numerical code for the calculation of these terms has been developed in order to obtain in a short time a very accurate estimate on complex configurations (generic body geometries even in the presence of external walls).The presence of perturbations and velocity gradients in the atmosphere causes additional aerodynamic loads that are particularly relevant for airships. These phenomena have been analyzed through unsteady CFD simulations. Subsequently a simplified model, based on stationary results, has been proposed fir the reconstruction of this loads, resulting accurate in prediction the aerodynamic characteristics of the body.Finally, we have proposed a complete model of the airship dynamics that in the future can be analysed and validated through experimental or numerical tests on generic airship configurations in unsteady and perturbed flows
Montgomery, Erin James. "Statistical estimation for non-homogeneous stochastic population models with particular application to manpower planning." Thesis, University of Ulster, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243742.
Full textKenja, Krishna. "Bayesian Parameter Estimation for Hyperelastic Constitutive Models of Soft Tissue under Non-homogeneous Deformation." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1515505801223584.
Full textYuan, Chaogui. "On non-homogeneous quasi-linear PDEs involving the p-Laplacian and the critical Sobolev exponent." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0007/NQ27272.pdf.
Full textReid, Cynthia 1958. "A class of solutions in non-homogeneous fluid dynamics obtained by the Riemann-invariant method /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66007.
Full textROSA, GUILHERME SIMON DA. "ELECTROMAGNETICS WAVE PROPAGATION IN COAXIAL GUIDES WITH NON-HOMOGENEOUS LOAD EXCITED BY THE TEM MODE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35451@1.
Full textCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE EXCELENCIA ACADEMICA
Neste trabalho são analisadas junções entre guias coaxiais não homogêneos com perdas. A expansão modal dos campos eletromagnéticos em um guia coaxial com duas camadas radiais é detalhadamente deduzida, e posteriormente a formulação é generalizada para guias com multicamadas radiais. As constantes de propagação para guias com perdas são determinadas pelo método do winding number, garantindo que todos os autovalores possam ser encontrados. O método do casamento de modos é aplicado na análise e projeto de estruturas coaxiais. A formulação é aplicada na otimização de estruturas de acoplamento e cornetas radiantes com carregamento dielétrico não homogêneo. O preenchimento não homogêneo é empregado nas estruturas radiantes a fim de minimizar a perda de retorno, e principalmente controlar e melhorar o formato do diagrama de radiação para operação em banda larga. Adicionalmente, a formulação é utilizada para analisar a propagação eletromagnética em sistemas de telemetria sem fio para poços de petróleo.
In this work, we analyzed junctions between coaxial waveguides heterogeneously filled with lossy dielectrics. The modal expansion of the electromagnetic fields in a coaxial waveguide with two radial layers is derived in detail, and afterward the formulation is generalized for a multilayer waveguide. The propagation constants for lossy waveguides are determined through the method of winding number, ensuring that all eigenvalues can be found. The mode matching technique is applied in the analysis and design of coaxial structures. The formulation is applied in the optimization of coupling structures and radiating horns with heterogeneous dielectric loading. The heterogeneous filling is used in radiating structures in order to reduce the return loss, and especially to control and improve the shape of the radiation pattern for broadband operation. Additionally, the formulation is used to analyze the electromagnetic propagation in wireless telemetry systems for oil wells.
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