Дисертації з теми "Power equations"
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Lagrange, John. "Power Series Solutions to Ordinary Differential Equations." TopSCHOLAR®, 2001. http://digitalcommons.wku.edu/theses/672.
Повний текст джерелаGrey, David John. "Parallel solution of power system linear equations." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5429/.
Повний текст джерелаEbrahimpour, Mohammad Reza. "An analytical study of the power flow equations with applications to systems with multiple close solutions." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/15746.
Повний текст джерелаGarcía-Blanco, Raquel. "Efficient solvers for power flow equations : parametric solutions with accuracy control assessment." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/458887.
Повний текст джерелаEl modelo de flujo de potencias se usa para predecir el comportamiento de redes eléctricas y desemboca en la resolución de un sistema de ecuaciones algebraicas no lineales. Modelar una red es esencial para optimizar su diseño y control. Ambas aplicaciones requieren una respuesta rápida a las múltiples peticiones de una familia paramétrica de problemas de flujo de potencias. Diversos métodos de resolución se diseñaron especialmente para resolver la versión algebraica de las ecuaciones de flujo de potencias. Sin embargo, no existe ninguna metodología que proporcione una solución explícita al problema paramétrico de flujo de potencias (esto quiere decir, un vademecum computacional explícito en términos de los parámetros). Esta tesis tiene como objetivo diseñar algoritmos que produzcan vademecums para el problema paramétrico de flujo de potencias. Una vez que las soluciones están disponibles, resolver problemas para diferentes valores de los parámetros es un posproceso extremadamente rápido (en tiempo real) y por lo tanto los problemas de diseño óptimo y control se pueden resolver inmediatamente. En la primera fase, una nueva familia de métodos de resolución iterativos para la versión algebraica del problema se construye. El método se basa en una formulación híbrida del problema combinado con un esquema de direcciones alternadas. Estos métodos se han diseñado para generalizarlos de forma que puedan resolver la versión paramétrica del problema siguiendo una estrategia llamada Descomposición Propia Generalizada (PGD). El método de resolución para el problema paramétrico calcula las incógnitas paramétricas usando la técnica PGD. El algoritmo sigue los mismo pasos que el algoritmo algebraico, pero algunas operaciones se llevan a cabo en el ambiente PGD, esto requiere algoritmos iterativos anidados. El método de resolución PGD se acompaña con una evaluación del error cometido permitiendo monitorizar la convergencia de los procesos iterativos y decidir el número de términos que requiere la solución para alcanzar la precisión preescrita. Diferentes ejemplos de redes reales y tests estándar se usan para demostrar el funcionamiento de las metodologías propuestas.
Beardmore, Robert Eric. "A study of bifurcations in singular differential equations motivated by electrical power systems." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310143.
Повний текст джерелаStein, Martin. "C0-Semigroup Methods for Delay Equations." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1225964082538-00880.
Повний текст джерелаIn the dissertation tools for the analysis of well-posedness and asymptotic behaviour of integro-differential equations and delay equations are developed. In the first part (chapter 1 and 2) methods for the determination of the modulus semigroup (smallest dominating C0-semigroup) of a C0-semigroup are provided and applied to various examples such as Volterra semigroups and evolution semigroups and transport evolution equations in networks. The main interest of the second part (chapter 3 and 4) is a type of an integro-differential equation which occurs in the modelling of the flutter of airfoils at subsonic speed. The remarkable property of the equation is the time derivative of the sought function in the integral term. A number of well-posedness criteria are proved for which integration by parts is not possible. The developed methods are also suitable for the derivation of new well-posedness results for other delay semigroups. Corresponding criteria are presented in chapter 4
Stein, Martin. "C0-Semigroup Methods for Delay Equations." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A23902.
Повний текст джерелаIn the dissertation tools for the analysis of well-posedness and asymptotic behaviour of integro-differential equations and delay equations are developed. In the first part (chapter 1 and 2) methods for the determination of the modulus semigroup (smallest dominating C0-semigroup) of a C0-semigroup are provided and applied to various examples such as Volterra semigroups and evolution semigroups and transport evolution equations in networks. The main interest of the second part (chapter 3 and 4) is a type of an integro-differential equation which occurs in the modelling of the flutter of airfoils at subsonic speed. The remarkable property of the equation is the time derivative of the sought function in the integral term. A number of well-posedness criteria are proved for which integration by parts is not possible. The developed methods are also suitable for the derivation of new well-posedness results for other delay semigroups. Corresponding criteria are presented in chapter 4.
Ahmed, Ibrahim. "Comparative evaluation of different power quality issues of variable speed wind turbines." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15920.
Повний текст джерелаFransson, Jonas. "Lower ramification numbers of wildly ramified power series." Thesis, Linnéuniversitetet, Institutionen för matematik (MA), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-35313.
Повний текст джерелаBall, John. "Volterra filtering for applications in nonoverlapping spectral problems." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/15372.
Повний текст джерелаGhanavati, Goodarz. "Statistical Analysis of High Sample Rate Time-series Data for Power System Stability Assessment." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/333.
Повний текст джерелаCaplen, Mark J. S. "The development and testing of a new integration method for the solution of stiff differential equations arising in the digital simulation of fluid power systems." Thesis, University of Bath, 1988. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383310.
Повний текст джерелаPretorius, Johannes Petrus. "Optimization and control of a large-scale solar chimney power plant." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/349.
Повний текст джерелаENGLISH ABSTRACT: The dissertation builds on previous research (Pretorius, 2004) and investigates the optimization and control of a large-scale solar chimney power plant. Performance results are based on a reference location near Sishen in South Africa and a so-called reference solar chimney power plant, with a 5000 m collector diameter and a 1000 m high, 210 m diameter chimney. The numerical simulation model is refined and used to perform a sensitivity analysis on the most prominent operating and technical plant specifications. Thermo-economically optimal plant configurations are established from simulation results and calculations according to an approximate plant cost model. The effects of ambient wind, temperature lapse rates and nocturnal temperature inversions on plant performance are examined. Various new technologies are investigated for the purpose of controlling plant output according to specific demand patterns. The incorporation of vegetation under the collector roof of the plant and the influence thereof on plant performance is also explored. Results indicate that, through the modification of the collector roof reflectance, collector roof emissivity, ground surface absorptivity or ground surface emissivity, major improvements on plant performance are possible. Introducing thermal insulation or double glazing of the collector roof also facilitates substantial enhancements on plant yield. Simulations predict a notable sensitivity to the ground surface absorptivity value, while variable atmospheric temperature lapse rates and windy ambient conditions may impair plant performance significantly. Furthermore, sand is found to be unsuitable as plant ground type and thermoeconomically optimal solar chimney plant dimensions are determined to be generally larger than plant dimensions employed in previous studies. Good dynamic control of solar chimney power output is established, suggesting that a solar chimney power plant can be implemented as a base or peak load electricity generating facility. Lastly, results predict that vegetation, when provided with sufficient water, will be able to survive under the collector roof but the inclusion of vegetation will however cause major reductions in plant performance.
AFRIKAANSE OPSOMMING: Die proefskrif bou op vorige navorsing (Pretorius, 2004) en ondersoek die optimering en beheer van 'n grootskaalse sonskoorsteen-kragstasie. Uitsetresultate word baseer op 'n verwysingsligging naby Sishen in Suid-Afrika en 'n sogenaamde verwysingskragstasie, met 'n kollektor deursnee van 5000 m en 'n 1000 m hoë, 210 m deursnee skoorsteen. Die numeriese rekenaarmodel is verbeter en gebruik vir die uitvoering van 'n sensitiwiteits-analise op die belangrikste bedryfs- en tegniese kragstasie spesifikasies. Termo-ekonomiese optimale aanlegkonfigurasies is bepaal volgens die uitsetresultate van die rekenaarmodel en benaderde aanleg-kosteberekeninge volgens 'n eenvoudige kostemodel. Die invloed van wind, atmosferiese temperatuur gradiënte en nagtelike temperatuur inversies op kragstasie uitset word beskou. Verskeie nuwe tegnologië word ondersoek met die doel om aanleg uitset te kan beheer volgens spesifieke elektrisiteit aanvraagspatrone. Die inkorporasie van plantegroei onder die kollektordak, en die invloed daarvan op kragstasie uitset, word ook beskou. Bevindings dui aan dat, deur die wysiging van die kollektordak refleksie, kollektordak emissiwiteit, grondoppervlak absorptiwiteit of grondoppervlak emissiwiteit, groot verbeterings op aanleg uitset moontlik is. Die implementering van termiese isolasie of 'n dubbelglaslaag vir die kollektordak veroorsaak ook 'n beduidende verheffing in kragstasie uitset. Simulasies voorspel 'n merkbare sensitiwiteit teenoor die grondoppervlak absorptiwiteitswaarde, terwyl veranderlike atmosferiese temperatuur daaltempos en winderige omgewingstoestande aanleg uitset beduidend mag belemmer. Verder is bevind dat sand ongeskik is as aanleg grond tipe en dat termo-ekonomiese optimale sonskoorsteen-kragstasie dimensies in die algemeen groter is as die aanvaarde aanlegdimensies van vorige studies. Goeie dinamiese beheer van sonskoorsteen-kragstasie uitset is bevestig, wat suggereer dat die sonskoorsteenkragstasie as 'n basis of pieklas elektrisiteitopwekkings-aanleg ingespan kan word. Ten laaste voorspel resultate dat plantegroei, mits dit voorsien word van genoegsame water, sal kan oorleef onder die kollektordak maar dat die inkorporasie van plantegroei die aanleg uitset beduidend sal benadeel.
Sponsored by the Centre for Renewable and Sustainable Energy Studies
HIPOLITO, FABIO C. "Avaliação das metodologias de análise de sistemas de tubulações de vapor sujeitas a carregamentos do tipo Steam Hammer." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26938.
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Carregamentos transientes termo hidráulicos do tipo Steam Hammer são eventos comuns em sistemas de tubulações de vapor com grandes potenciais de catástrofes em plantas de geração de energia. Uma vez iniciado o evento, ondas de pressões são geradas com amplitudes, geralmente, de grande magnitude ocasionando altas pressões no sistema, ruídos, deformações, fadiga, com possibilidade de danos materiais e econômicos e em casos extremos fatalidades. Os procedimentos da indústria para análise deste tipo de sistema consistem realização de análises estáticas equivalentes ou análise de espectro de resposta com carregamentos caracterizados por meio de métodos analíticos baseados em hipóteses simplificadoras do fluido e fluxo. Neste trabalho é proposta a analise de sistema de tubulações por meio do método de integração numérica com superposição modal e carregamento caracterizado por método numérico com base no método das características. Comparações foram efetuadas entre os resultados obtidos pela metodologia proposta e os procedimentos da indústria, demonstrando que, dado ao alto grau de conservadorismo, os procedimentos da indústria acarretam em superdimensionamento de estruturas e tubulações ocasionando custos adicionais de projeto, sendo a otimização do projeto obtida aplicando-se a metodologia proposta no trabalho.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Vaičiulytė, Ingrida. "Vienos išsigimstančios dalinių išvestinių diferencialinių lygčių sistemos sprendinių struktūra." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20090827_111608-87412.
Повний текст джерелаIn this work the system of four degenerating differential equations with partial derivatives of first order was studied. For the solution of system of differential equations with partial derivatives the method of generalized power series was applied. Analytical solutions of this system were found and properties of solutions on neighbourhood of points of degeneration manifold were investigated. The method of generalized power series can be applied to the solution of systems of differential equations with partial derivatives of similar structure, which order is degenerating. The results, which were obtained in this work, can be applied to modelling and studying the real processes.
Сиротин, Юрий Александрович. "Компенсация и учет реактивной мощности в электротехнических системах с несимметричными режимами". Thesis, НТУ "ХПИ", 2014. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21116.
Повний текст джерелаThesis for a Doctor’s degree in Engineering Sciences by specialty 05.09.03 - Electrical Engineering Complexes and Systems. - National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2015. The dissertation is devoted an important scientific and technical issues to improve the power quality of supply and consumption (SC) in three-phase networks through further development of die power theory, development of methods and ways of compensation, proposals for the accounting and payment of the inactive components of the apparent power (AP). A generalized mathematical model (GMM) of electric power processes (EPP) in a 3-phase SC scheme was developed. The model of 3-wire circuit is provided by a special (О-balanced) mode of the model 4-wire circuit The developed GMM classifies the SC modes using the vectorial instantaneous power (IP) and summarizes the class of models used in the theory of IP. For sinusoidal mode with asymmetric voltage the refines vectorial mathematical model (VMV) 3-phasors (complex rms vectors) was created. The analytical expressions for the integral characteristics of the classified modes are founded and their relationship with standard IP and vectorial IP are established. With asymmetrical voltage and asymmetrical loading a sinusoidal mode can be both unbalanced and pulsed. Each mode is represented by its power equation and the equivalent orthogonal decomposition of the 3-phase current Both decompositions are used to create the optimal mode of SC with a constant IP at asymmetrical voltage. The proposed compensator provides the non-puised energy supply with the highest possible power factor and with the same average (active) power as the initial current. Based on the evaluation and calculation of the power equation components of a unbalanced mode was developed a methodology for calculating the loss of the measuring selection. A methodology and technique of analytical calculation of additional losses on the passport data of the connected electrical equipment was proposed. Formulated and proved offers on differential measurement and payment of the energy components of AP will stimulate consumer sets the compensator, and provide a reliable methodology for improving the quality of SC (within unbalance loading and voltage).
SABUNDJIAN, GAIANE. "Aplicação do método da expansão em funções hierárquicas na solução das equações de Navier-stokes para fluidos incompressíveis." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11624.
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Tese (Doutoramento)
IPEN/T
Escola Politecnica, Universidade de Sao Paulo - POLI/USP
González, Zumba Jorge Andrés. "Dynamic Modeling and Stability Analysis of Stochastic Multi-Physical Systems Applied to Electric Power Systems." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/158558.
Повний текст джерела[CA] La naturalesa aleatòria que caracteritza alguns fenòmens en sistemes físics reals (e.g., enginyeria, biologia, economia, finances, epidemiologia i uns altres) ens ha plantejat el desafiament d'un canvi de paradigma del modelatge matemàtic i l'anàlisi de sistemes dinàmics, i a tractar els fenòmens aleatoris com a variables aleatòries o processos estocàstics. Aquest enfocament nou ha portat com a conseqüència noves especificitats que la teoria clàssica del modelatge i anàlisi de sistemes dinàmics deterministes no ha pogut cobrir. Afortunadament, meravelloses contribucions, realitzades sobretot en l'últim segle, des del camp de les matemàtiques per científics com Kolmogorov, Langevin, Lévy, Itô, Stratonovich, només per nomenar alguns; han obert les portes per a un estudi ben fonamentat de la dinàmica de sistemes físics pertorbats per soroll. En la present tesi es discuteix l'ús d'equacions diferencials algebraiques estocàstiques (EDAEs) per al modelatge de sistemes multifísicos en xarxa afectats per pertorbacions estocàstiques, així com l'avaluació de la seua estabilitat asimptòtica a través d'exponents de Lyapunov (ELs). L'estudi està enfocat en EDAEs d-index-1 i la seua reformulació com a equacions diferencials estocàstiques ordinàries (EDEs). Fonamentats en la teoria ergòdica, és factible analitzar els ELs a través de sistemes dinàmics aleatoris (SDAs) generats per EDEs subjacents. Una vegada garantida l'existència d'ELs ben definides, hem procedit a l'ús de tècniques de simulació numèrica per a determinar els ELs numèricament. Hem implementat mètodes numèrics basats en descomposició QR discreta i contínua per al còmput de la matriu de solució fonamental i el seu ús en el càlcul dels ELs. Les característiques numèriques i computacionals més rellevants de tots dos mètodes s'illustren mitjançant proves numèriques. Tota aquesta investigació sobre el modelatge de sistemes amb EDAEs i avaluació de la seua estabilitat a través d'ELs calculats numèricament, té una interessant aplicació en enginyeria. Aquesta és l'avaluació de l'estabilitat dinàmica de sistemes elèctrics de potència. En el present treball de recerca, implementem els nostres mètodes numèrics basats en descomposició QR per al test d'estabilitat dinàmica en dos models de sistemes elèctrics de potència d'una-màquina bus-infinit (OMBI) afectats per diferents pertorbacions sorolloses. L'anàlisi en xicotet-senyal evidencia el potencial de les tècniques proposades en aplicacions d'enginyeria.
[EN] The random nature that characterizes some phenomena in the real-world physical systems (e.g., engineering, biology, economics, finance, epidemiology, and others) has posed the challenge of changing the modeling and analysis paradigm and treat these phenomena as random variables or stochastic processes. Consequently, this novel approach has brought new specificities that the classical theory of modeling and analysis for deterministic dynamical systems cannot cover. Fortunately, stunning contributions made overall in the last century from the mathematics field by scientists such as Kolmogorov, Langevin, Lévy, Itô, Stratonovich, to name a few; have opened avenues for a well-founded study of the dynamics in physical systems perturbed by noise. In the present thesis, we discuss stochastic differential-algebraic equations (SDAEs) for modeling multi-physical network systems under stochastic disturbances, and their asymptotic stability assessment via Lyapunov exponents (LEs). We focus on d-index-1 SDAEs and their reformulation as ordinary stochastic differential equations (SDEs). Supported by the ergodic theory, it is feasible to analyze the LEs via the random dynamical system (RDSs) generated by the underlying SDEs. Once the existence of well-defined LEs is guaranteed, we proceed to the use of numerical simulation techniques to determine the LEs numerically. Discrete and continuous QR decomposition-based numerical methods are implemented to compute the fundamental solution matrix and use it in the computation of the LEs. Important numerical and computational features of both methods are illustrated through numerical tests. All this investigation concerning systems modeling through SDAEs and their stability assessment via computed LEs finds an appealing engineering application in the dynamic stability assessment of power systems. In this research work, we implement our QR-based numerical methods for testing the dynamic stability in two types of single-machine infinite-bus (SMIB) power system models perturbed by different noisy disturbances. The analysis in small-signal evidences the potential of the proposed techniques in engineering applications.
Mi agradecimiento al estado ecuatoriano que, a través del Programa de Becas para el Fortalecimiento y Desarrollo del Talento Humano en Ciencia y Tecnología 2012 de la Secretaría Nacional de Educación Superior, Ciencia y Tecnología (SENESCYT), han financiado mis estudios de doctorado.
González Zumba, JA. (2020). Dynamic Modeling and Stability Analysis of Stochastic Multi-Physical Systems Applied to Electric Power Systems [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/158558
TESIS
Varga, David. "Bezdrátový přenos výkonu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-218912.
Повний текст джерелаNazareno, Ivo Sechi. "Mecanismo de instabilidade devido a grandes perturbações em sistemas elétricos de potência modelados por equações algébrico-diferenciais." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-16112009-152004/.
Повний текст джерелаThis thesis addresses to the mechanisms that lead an electric power system to instability due to large disturbances and to the methods to assess directly the stability margin when the system is modeled preserving the network structure. The system is modeled by a set of differential-algebraic equations (DAE) that permits more comprehensive models for the load and network and provides a better stability margin assessment when compared to the model of ordinary differential equations (ODE) traditionally used for transient stability analysis. The direct assessment of the stability margin was realized using direct methods based on the controlling unstable equilibrium point (CUEP) concept and permits to assess the margin in a local and fast manner, without requires the time integration of the post-fault system differential equations. Nevertheless, some open problems remain to be solved in order to provide a complete foundation of the CUEP method for DAE power system models. In this research a further step is given in this direction, showing that the existent definitions for the CUEP and other interest points may fail, mainly when the fault-on trajectory reaches singular surfaces. In this sense, it is proposed the correction of these definitions and a new CUEP method that is adequate to the angular and voltage short-term direct stability assessment due to large disturbances; capable to provide precise critical clearing times and the identification of the instability mechanisms for the DAE modeled power system, even in the presence of singular surfaces.
Michalkovič, Aleksejus. "Netiesinės algebrinės lygčių sistemos sprendinių skaičiaus analizė." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100813_142631-54742.
Повний текст джерелаSince the introduction of Diffie-Hellman key agreement protocol in 1976 computer technology has made a giant step forward. Nowadays there is not much time left before quantum computers will be in every home. However it was theoretically proven that discrete logarithm problem which is the basis for Diffie-Hellman protocol could be solved in polynomial time using such computers. Such possibility would make D-H protocol insecure. Thus cryptologists are searching for different ways to improve the security of the protocol by using hard problems. One of the ways to do so is to introduce secure one-way functions (OWF). In this paper a new kind of OWF called the matrix power function will be analyzed. Professor Eligijus Sakalauskas introduced this function in 2007 and later used this function to construct a Diffie-Hellman type key agreement protocol using square matrices. This protocol is not only based on matrix power function but also on commutative matrices which are defined in finite fields or rings. Thus an algebraic non-linear system of equations is formed. The security of this system will be analyzed. It will be shown that we can use matrix power function in cryptography. We will also be analyzing how does the solution of the system depend on system parameters: the order of matrices and a parameter p which defines a finite group Z_p. We will also briefly discuss the usage of this system in real life and the algebraic properties of the suggested OWF.
Kong, Yafang, and 孔亚方. "On linear equations in primes and powers of two." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50533769.
Повний текст джерелаpublished_or_final_version
Mathematics
Doctoral
Doctor of Philosophy
Peat, Rhona Margaret. "Fractional powers of operators and mellin multipliers." Thesis, University of Strathclyde, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366801.
Повний текст джерелаSong, Xuefeng. "Dynamic modeling issues for power system applications." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1591.
Повний текст джерелаMasaki, Satoshi. "Asymptotic expansion of solutions to the nonlinear Schrödinger equation with power nonlinearity." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/124383.
Повний текст джерелаTeixeira, Denis Leocádio. "Determinação do gradiente de pressão estática do ar para sistemas de compostagem por aeração forçada." Universidade Federal de Viçosa, 2014. http://locus.ufv.br/handle/123456789/3672.
Повний текст джерелаCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Although there equations and graphics in scientific literature to estimate the static pressure gradient of airflow through layers of grains and seeds, studies using organic waste submitted to composting treatment are scarce. The objective of this study was to adjust equations to estimate the static pressure gradient of airflow through layers of different organic residues. The waste used were chicken litter and as bulking agents and carbon source: sugarcane bagasse, sawdust and coffee husk which were mixed in the ratio of 0; 10; 20; 30 e 40% (volumetric basis), of chicken litter in relation to bulking agents, as well as mixture with C/N ratio of 25/1, which were submitted to composting process. Measurements of static pressure drop in layers of organic waste before and after the composting process, and in layers of material from the different proportions of chicken litter added to bulking agents, were performed using a prototype with specific airflow rates ranging from 0.02 to 0.13 m 3 s -1 m -2. The static pressure drop of airflow increased as a power of the material layer thickness. Static pressure gradient in layers of organic waste decrease with the composting process. Shedd, Hukill & Ives and Hunter models may be used to predict the static pressure gradient of air to be blown through the organic residues layers, however, the Shedd model was that which best represented the phenomenon studied. Lower values of static pressure gradient were obtained in layers without chicken litter and the higher values obtained in layers composed of mixture of chicken litter in proportion of 40%. Equations to estimate the static pressure gradient for different proportions of chicken litter may be clustered, yielding models that can explain the variation of pressure gradient for each bulking agent and carbon source.
Embora existam, na literatura científica, equações e gráficos para estimativa do gradiente de pressão estática do ar, quando forçado em camadas de grãos e sementes, são poucos os trabalhos realizados utilizando-se resíduos orgânicos submetidos ao tratamento por compostagem. Neste trabalho, teve-se por objetivo o ajuste de equações que possibilitassem a estimativa do gradiente de pressão estática do ar, quando insuflado em camadas de diferentes materiais orgânicos. Os resíduos utilizados foram a cama de frango e, como agentes estruturantes e fonte de carbono, o bagaço de cana-de-açúcar, a serragem de madeira e a palha de café, os quais foram misturados nas proporções de 0; 10; 20; 30 e 40% (base volumétrica) de cama de frango em relação aos agentes estruturantes, além de misturas com relação C/N de 25/1, as quais foram submetidas ao tratamento por compostagem. As medições da queda de pressão estática do ar, ao atravessar camadas de material orgânico, antes e depois de ter sido submetido ao tratamento por compostagem, e nas camadas de materiais provenientes das diferentes proporções de cama de frango adicionada aos agentes estruturantes, foram realizadas utilizando-se um protótipo, no qual o material foi submetido a vazões específicas de ar que variaram de 0,02 a 0,13 m 3 s -1 m -2 . A queda na pressão estática do ar aumentou de forma potencial com a espessura da camada de material. No que se refere ao decurso do processo de compostagem, este contribuiu para redução do gradiente de pressão estática do ar ao atravessar as camadas de material orgânico. Os modelos matemáticos de Shedd, Hukill & Ives e Hunter podem ser utilizados para predizer o gradiente de pressão estática do ar, ao ser insuflado em camadas de resíduos orgânicos, no entanto, o modelo de Shedd pode ser considerado, em termos estatísticos, o que melhor representou o fenômeno em estudo. Menores valores de gradientes de pressão estática do ar foram obtidos em camadas sem adição de cama de frango e os maiores obtidos nas camadas constituídas pela mistura com cama de frango na proporção de 40%. As equações obtidas para estimativa do gradiente de pressão estática do ar, para as diferentes proporções de cama de frango, podem ser agrupadas, originando modelos capazes de explicar a variação do gradiente de pressão para cada agente estruturante e fonte de carbono.
CRUZ, Thamires Santos. "Uma teoria de regularidade para equações de volterra fracionárias com dados iniciais locais e não locais." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18454.
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CNPQ
Este trabalho trata da teoria de existência, unicidade, regularidade, continuação e alternativa de Blow-up de solução brandas para Equação de Volterra Fracionarias com condições iniciais locais cujo termo não linear satisfaz certas propriedades localmente Lipschitz. Analisamos também o caso de condições iniciais não locais e não linearidades verificando condições do tipo Caratheodory. Neste caso estudamos as propriedades topológicas do conjunto soluções de tais equações.
his work deals with existence, uniqueness, regularity, continuation and Blow up Alternative of mild solutions for Fractional Volterra Equations with local initial conditions, whose nonlinear terms satisfy some locally Lipschitz properties. Moreover we analyse thecase of nonlocal initial conditions and nonlinearities of Caratheodory type. In this case, we study topological properties of the solution set of such equations.
Gu, Chunguang 1970. "Constitutive equations for granular materials : application to dry sand and powder metal." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9263.
Повний текст джерелаIncludes bibliographical references (leaves 138-139).
Strain localization into shear bands is commonly observed in natural soil masses, as well as in human-built embankments, footings, retaining walls and other geotechnical structures. Although the onset of strain localization can be derived from standard bifurcation analyses, few numerical simulations of the complete process of strain localization in granular materials have been previously reported. Predictions for the onset and process of shear band formation are critically dependent upon the constitutive equations employed. In this thesis, a new physically based constitutive model is formulated for describing the plastic flow of cohesionless granular materials. This constitutive model has been implemented in the finite element package ABAQUS/explicit(1999) and is used to predict the strain localization in geomaterials. The numerical calculations are shown to be in good quantitative agreement with the recent corresponding experiments of Han and Drescher(1993) and Alsiny et al. (1992) on the localization in dry Ottawa sand under low pressure conditions. The physical description for the plastic flow enables the model to reproduce the macroscopic stress strain response and the complete strain localization process. The complex evolution of the strain localization from "Riedel shear" to "boundary shear" in the shearing experiment of a simulated gouge layer (Marone et al., 1990,1999) has been captured in our simulations. This physically based constitutive model is also able to predict the startling "stress dip" in a static sandpile - the vertical stress is not maximum under the apex of the pile, but shows a local dip there. Next, we shall focus on metal powders, which are commonly used in powder metallurgy industry to form net- or near-net-shaped components with high relative density by cold compaction. A new constitutive model for cold compaction of metal powders has been developed. The plastic flow of metal powders at the macroscopic level is assumed to be representable as a combination of a distortion mechanism, and a consolidation mechanism. For the distortion mechanism the model employs a pressure-sensitive, Mohr-Coulomb type yield condition, and a new physically based non-associated flow rule. For the consolidation mechanism the model employs a smooth yield function which has a quarter-elliptical shape in the mean-normal pressure and the equivalent shear stress plane, together with an associated flow rule. The constitutive model has been implemented in a finite element program. The material parameters in the constitutive model have been calibrated for MH-100 iron powder by fitting the model to reproduce data from true triaxial compression experiments, torsion ring-shear experiments, and simple compression experiments. The predictive capability of the constitutive model and computational procedure is checked by simulating two simple powder forming processes: (i) a uniaxial strain compression of a cylindrical sample, and (ii) forming of a conical shaped-charge liner. In both cases the predicted load-displacement curves and density variations in the compacted specimens are shown to compare well with corresponding experimental measurements.
by Chunguang Gu.
Ph.D.
Martin, Andrew John. "A High Performance Parallel Sparse Linear Equation Solver Using CUDA." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1310603635.
Повний текст джерелаBrown, Robert Winston, and rwb@rmit edu au. "Electrical and Thermal Modelling of Low Power Metallised Polypropylene Capacitors." RMIT University. Electrical and Computer Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080130.155318.
Повний текст джерелаGuarguaglini, Marco. "Laser-driven shock compression of liquid mixtures and silica up to extreme thermodynamic conditions of interest for planetary interior models." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX075/document.
Повний текст джерелаCharacterising the behaviour of planetary interiors’ components at extreme conditions (megabar pressures, temperatures of a few thousand Kelvin) is essential to build reliable models describing the evolution and structure of planets. In this thesis, we investigated various components on a wide set of conditions using laser-driven shock compression techniques at the LULI2000 (France) and GEKKO XII (Japan) facilities.Single decaying shocks were employed to study high-pressure / high-temperature states. To reach moderate-temperature conditions, closer to planetary interior profiles, we employed static and dynamic pre-compression techniques coupling Diamond Anvil Cells to shock compression and generating double shocks, respectively.We studied the equation of state of water-ethanol-ammonia mixtures and of pure liquid water and ammonia, of interest for icy giant structure models. Pure ammonia measurements have been particularly challenging due to cell design complexity in reason of its reactivity; we provide the first data obtained with laser shocks, in a pressure domain up to now unexplored. Mixtures data are in agreement with recent ab initio calculations based on the linear mixing approximation.We measured the optical reflectivity of liquid mixtures and silica, a key component of rocky planets’ interiors. From reflectivity data we estimated the electrical conductivity of such components — a crucial parameter for modelling the generation of planetary magnetic fields in the interiors via a dynamo mechanism.Water, ammonia, and water-ethanol-ammonia mixtures exhibit different reflectivity (hence conductivity) behaviours as a function of pressure and temperature. This suggests that pure water should not be used in dynamo models as representative of the icy mixtures.Moreover, we provide the first experimental confirmation of recent ab initio studies showing that the conductivity of silica along isothermal lines is not monotonic at moderate temperatures. Our data provide experimental support for the calculations predicting a dynamo action to occur in super-Earths’ and early Earth’s magma oceans
Dowling, Alexander W. "An Equation-based Framework for Large-Scale Flowsheet Optimization and Applications for Oxycombustion Power System Design." Research Showcase @ CMU, 2015. http://repository.cmu.edu/dissertations/568.
Повний текст джерелаWENG, CHIYUAN. "Transient Stability Analysis of Power Systems with Energy Storage." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1348453228.
Повний текст джерелаЛютий, Тарас Володимирович, Тарас Владимирович Лютый, Taras Volodymyrovych Liutyi, Станіслав Іванович Денисов, Станислав Иванович Денисов, Stanislav Ivanovych Denysov, Олександр Юрійович Поляков, Александр Юрьевич Поляков, Oleksandr Yuriiovych Poliakov, and C. Binns. "Power Loss of the Nanoparticle Magnetic Moment in Alternating Fields." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35370.
Повний текст джерелаTekaya, Wajdi. "Risk neutral and risk averse approaches to multistage stochastic programming with applications to hydrothermal operation planning problems." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47582.
Повний текст джерелаLindsay, Tara Reeves. "Applying Adaptive Prognostics to Rolling Element Bearings." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7568.
Повний текст джерелаMARTINS, FERNANDO R. "Medidas de parametros nucleares de um reator de potencia zero aplicando a tecnica de analise de ruidos." reponame:Repositório Institucional do IPEN, 1992. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10294.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Whitman, Daniel Joseph. "Electromagnetic Fields, Power Losses, and Resistance of High-Frequency Magnetic Devices." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1268951694.
Повний текст джерелаKuntz, Sarah Louise. "Feasibility of Attaining Fully Equiaxed Microstructure through Process Variable Control for Additive Manufacturing of Ti-6Al-4V." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1464557846.
Повний текст джерелаWang, Rui. "Distributed Cooperative Communications and Wireless Power Transfer." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/62.
Повний текст джерелаMukherjee, Swagato. "Parabolic Wave Equation based Model for Propagation through Complex and Random Environments." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595529187539516.
Повний текст джерелаAbraham, Etimbuk. "Adaptive supervisory control scheme for voltage controlled demand response in power systems." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/adaptive-supervisory-control-scheme-for-voltage-controlled-demand-response-in-power-systems(3e64537d-52c7-4eb5-87f2-b73fe920b9cb).html.
Повний текст джерелаSu, Heyin. "Modeling of Proposed Changes to SIUC Central Heating, Air-Conditioning, and Power Plant Incorporating Variable Frequency Drive (VFD) and High Efficiency Turbine." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/708.
Повний текст джерелаDolan, Amanda Avery. "Synthesizing Undergraduate College Student Persistence: A Meta-analytic Structural Equation Model." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1554756614807579.
Повний текст джерелаMahmoodi, Foad. "Compression Mechanics of Powders and Granular Materials Probed by Force Distributions and a Micromechanically Based Compaction Equation." Doctoral thesis, Uppsala universitet, Institutionen för farmaci, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-171874.
Повний текст джерелаKipps, Mark Rew. "A modular approach to modeling an isolated power system on a finite voltage bus using a differential algebraic equation solving routine." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA281036.
Повний текст джерелаŠtumpf, Martin. "Implementation and Test of a 2D-integral-equation MoM-algorithm for the Analysis of Power-Bus Structures on Printed Circuit Boards." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217683.
Повний текст джерелаMacêdo, Renata Araripe de. "Algoritmo baseado na equação diferencial para proteção rápida de linhas de transmissão." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-16042018-145737/.
Повний текст джерелаThe present work shows the development of an algorithm based on the modeling of the transmission system utilizing differential equations. The differential equation for the line is solved having its resistance and inductance as parameters. In this approach there is no need for the algorithm inputs to be pure sinusoidal, allowing the presence of harmonic and DC components in the line as a part of the solution to the problem. The software ATP was utilized for the modeling of the electric system under study as well as data collection for analysis and tests. This representation allowed a detailed representation of the transmission line through the characteristics of the conductors and its geometrical disposition in the transmission towers, as well as the simulation of faults that usually affect the electric system, reproducing a realistic situation. The direct use of differential equations do not give an acceptable estimation as far as digital relays are concerned because they have convergence times over two cycles. In this sense, a 5th order median filter was utilized, providing faster diagnosis for the fault location estimation. The estimation of the fault location has proved to be a coherent criteria for the algorithm. For the fault types tested, the estimation for the fault location utilizing line parameters has shown itself highly satisfactory for protection purposes. This work has shown that the algorithm oulputs converge in less than 1 and a half cycles afler the fault occurrence, presenting a much faster response for digital relays.
Vellmer, Sebastian. "Applications of the Fokker-Planck Equation in Computational and Cognitive Neuroscience." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21597.
Повний текст джерелаThis thesis is concerned with the calculation of statistics, in particular the power spectra, of point processes generated by stochastic multidimensional integrate-and-fire (IF) neurons, networks of IF neurons and decision-making models from the corresponding Fokker-Planck equations. In the brain, information is encoded by sequences of action potentials. In studies that focus on spike timing, IF neurons that drastically simplify the spike generation have become the standard model. One-dimensional IF neurons do not suffice to accurately model neural dynamics, however, the extension towards multiple dimensions yields realistic behavior at the price of growing complexity. The first part of this work develops a theory of spike-train power spectra for stochastic, multidimensional IF neurons. From the Fokker-Planck equation, a set of partial differential equations is derived that describes the stationary probability density, the firing rate and the spike-train power spectrum. In the second part of this work, a mean-field theory of large and sparsely connected homogeneous networks of spiking neurons is developed that takes into account the self-consistent temporal correlations of spike trains. Neural input is approximated by colored Gaussian noise generated by a multidimensional Ornstein-Uhlenbeck process of which the coefficients are initially unknown but determined by the self-consistency condition and define the solution of the theory. To explore heterogeneous networks, an iterative scheme is extended to determine the distribution of spectra. In the third part, the Fokker-Planck equation is applied to calculate the statistics of sequences of binary decisions from diffusion-decision models (DDM). For the analytically tractable DDM, the statistics are calculated from the corresponding Fokker-Planck equation. To determine the statistics for nonlinear models, the threshold-integration method is generalized.
Weitzel, William R. "EVALUATION OF OVERPRESSURE WAVE TRANSITION BY AIRBLAST OVERPRESSURE AND SHOCK WAVE ATTENUATION ANALYSIS USING A SMALL BLACK POWDER CHARGE." UKnowledge, 2014. http://uknowledge.uky.edu/mng_etds/17.
Повний текст джерела