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1
Cayan, Fatma Nihan. "The Method Of Lines Solution Of Discrete Ordinates Method For Nongray Media." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607401/index.pdf.
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A radiation code based on method of lines (MOL) solution of discrete ordinates method (DOM) for the prediction of radiative heat transfer in nongray absorbing-emitting media was developed by incorporation of two different gas spectral radiative property models, namely wide band correlated-k (WBCK) and spectral line-based weighted sum of gray gases (SLW) models.
Predictive accuracy and computational efficiency of the developed code were assessed by applying it to the predictions of source term distributions and net wall radiative heat fluxes in several one- and two-dimensional test problems including isothermal/non-isothermal and homogeneous/non-homogeneous media of water vapor, carbon dioxide or mixture of both, and benchmarking its steady-state predictions against line-by-line (LBL) solutions and measurements available in the literature. In order to demonstrate the improvements brought about by these two spectral models over and above the ones obtained by gray gas approximation, predictions obtained by these spectral models were also compared with those of gray gas model. Comparisons reveal that MOL solution of DOM with SLW model produces the most accurate results for radiative heat fluxes and source terms at the expense of computation time when compared with MOL solution of DOM with WBCK and gray gas models.
In an attempt to gain an insight into the conditions under which the source term predictions obtained with gray gas model produce acceptable accuracy for engineering applications when compared with those of gas spectral radiative property models, a parametric study was also performed. Comparisons reveal reasonable agreement for problems containing low concentration of absorbing-emitting media at low temperatures.
Overall evaluation of the performance of the radiation code developed in this study points out that it provides accurate solutions with SLW model and can be used with confidence in conjunction with computational fluid dynamics (CFD) codes based on the same approach.
2
Suwan, Kumpanat. "The 'method of lines' applied to waterhammer computation." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316718.
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Ghimire, Sushma. "Analysis of Fault location methods on transmission lines." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1800.
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Analysis of different types of fault is an important and complex task in a power system. Accurate fault analysis requires models that determine fault distances in a transmission line. The mathematical models accurately capture behavior of different types of faults and location in a timely manner, and prevents damaging power system from fault energy. The purpose of this thesis is to use two methods for determining fault locations and their distance to the reference end buses connected by the faulted transmission line. The two methods used in this investigation are referred to as impedance-based and traveling wave methods. To analyze both methods, various types of faults were modeled and simulated at various locations on a two-bus transmission system using EMTP program. Application and usefulness of each method is identified and presented in the thesis. It is found that Impedance-based methods are easier and more widely used than traveling-wave methods.
4
Keen, Alan G. "Planar transmission line analyses using the Method of Lines." Thesis, University of Kent, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293993.
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LUSTOSA, EDUARDO MAGALHAES. "DYNAMICS OF SHIPPING LINES USING THE FINITE ELEMENT METHOD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2000. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=26484@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOREste trabalho apresenta uma abordagem pelo método dos elementos finitos para o cálculo da resposta tridimensional, estática e dinâmica, de estruturas unidimensionais total ou parcialmente imersas em um fluido em movimento. A técnica utilizada baseia-se na separação do movimento de corpo rígido dos deslocamentos totais do elemento resultando naqueles que efetivamente causam deformações, consideradas infinitesimais, sob condições de rotações finitas. A posição da estrutura é definida por um conjunto de eixos co-rotacionados e a avaliação das rotações deste sistema é detalhada. O estudo apresentado considera as não-linearidades decorrentes da mudança de geometria, do acoplamento entre os mecanismos de rigidez axial e transversal e do carregamento hidrodinâmico, considerado proporcional ao quadrado da velocidade relativa entre fluido e estrutura. Na discretização espacial das equações de equilíbrio, a hipótese de pequenas deformações é empregada. Desta forma, a utilização do sistema de coordenada co-rotacionado permite considerar-se um elemento de dois nós baseado no modelo de viga de Euler-Bernoulli com funções de interpolação dos deslocamentos nodais utilizando os polinômios cúbicos de Hermite e referidos ao sistema convectivo de cada elemento. Na integração temporal das equações de equilíbrio, utiliza-se o procedimento passo-a-passo de Newmark juntamente com a técnica iterativa de Newton-Raphson, obtendo-se, a cada instante de tempo, a configuração correspondente ao equilíbrio dinâmico da estrutura discretizada. O procedimento apresentado foi implementado em um programa de computador tendo-se verificado, para diversos exemplos, uma convergência satisfatória entre os resultados do modelo implementado e aqueles obtidos de outros com origem independente.
This work presents a finite element approach to the three-dimensional static and dynamic response calculations of slender structures totally or partially immersed in a moving fluid. The technique is based on the separation of rigid body motions from the element total displacements resulting in those that effectively cause strain, and which are assumed infinitesimal, under conditions of finite rotations. The position of the structure is defined by a set of co-rotational axes and the evaluation of the finite rotations of this system is detailed. The study considers the non-linearities due to change in geometry, coupling between the axial and bending stiffness mechanisms and the velocity-squared drag loading. For the spatial discretization of the equilibrium equations, the small strain hypothesis is employed. The use of the co-rotational coordinate system makes possible to consider a two node element based on the Euler-Bernoulli beam kinematic model, with cubic Hermitian interpolation functions for the nodal displacements obtained at the convective coordinate system of each element. The Newmark step-by-step scheme is applied to directly integrate, in the time domain, the equilibrium equations and the Newton-Raphson iterative algorithm employed t solve the resultinh incremental non-linear set of equations, at each time step. The presented procedure was implemented in a computer program and various example results were satisfactorily tested against the ones obtained from independent programs.
6
Kim, Sangwoo. "Multiconductor transmission line analysis using surface ribbon method /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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VALE, Tassio Ferreira. "Using a Multi-Method Approach for Evaluating Service Identification Methods in Service-Oriented Product Lines." reponame:Repositório Institucional da UFPE, 2012. https://repositorio.ufpe.br/handle/123456789/11360.
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A combinação de Linhas de Produto de Software (LPS) e Computação Orientada a Serviços (COS) tem recebido atenção de pesquisadores e praticantes, já que uma área é capaz de solucionar determinados problemas da outra. A junção dessas duas áreas é chamada de Linha de Produto Orientada a Serviços (LPOS), e tem se mostrado uma área de pesquisa emergente nos últimos anos. No contexto da Computação Orientada a Serviços, identificação de serviços é uma das primeiras atividades para modelagem de uma solução COS, e consiste na determinação de serviços candidatos. Essa não é uma tarefa trivial, e os erros adquiridos durante a identificação de um serviço pode propagar-se para as atividades subsequentes do processo de desenvolvimento orientado a serviços. Existem diversas propostas para identificação de serviços. Apesar da diversidade, não existe um método de identificação de serviços capaz de adequar-se a diversos contextos e necessidades. Considerando a heterogeneidade desses métodos, esta dissertação tem o objetivo de verificar quais métodos podem ser aplicados em linhas de produto de software, bem como as vantagens, desvantages e desafios existentes neste campo. Esta pesquisa utilizou uma abordagem multi-métodos, que combina estudos primários e secundários a fim de incrementar o corpo de conhecimento em determinada área baseada nos achados de tal investigação. Desta forma, este trabalho utilizou um método secundário (revisão sistemática) e dois métodos primários com o intuito de aumentar a confiabilidade dessa pesquisa. Além disso, foi realizada uma revisão da literatura a fim de coletar as abordagens de identificação de serviços existentes, visando propor uma recomendação dos métodos mais adequados considerando três cenários de LPS: top-down, bottom-up e hybrid. Esta recomendação foi avaliada através de um estudo de caso com uma linha de produto de sistemas médicos, usando dois metodos classificados no cenário o qual os sistemas médicos encontram-se, top-down. A principal contribuição dessa pesquisa é prover um instrumento que auxilie os interessados em identificar serviços a escolher um método apropriado, levando em consideração o cenário SPL a ser aplicado. Os resultados do estudo de caso mostram que as abordagens de identificação de serviços podem ser aplicadas num contexto de LPS. Além disso, este métodos facilitam a realização da atividade de identificação.
The combination of Software Product Line (SPL) and Service-Oriented Computing (SOC) have started to receive attention by researchers and practitioners, since they can address issues of each other. Putting these two areas together is called Service-Oriented Product Lines Enginering (SOPLE), presenting itself as an emerging area in the last years. In the Service-Oriented Computing, service identification is one of the first activities in the modeling of a SOC solution, that consists of determining candidate services. This is not a trivial task, and the errors made during the identification can propagate mistakes to the next activities of the service-oriented development process. There are several proposals addressing service identification for several contexts. However, an unified method for identifying services has not yet been reached. Regarding the heterogeneity of these methods, this dissertation aims to verify which methods can be applied in the SPL context, the advantages, disadvantages and the existing challenges of this field. This research used a multi-method approach that combines primary and secondary studies in order to increase the availability of empirical knowledge based on the findings of the investigation. Thus, this work used one secondary method (systematic review) and two primary methods (survey and case study) to address it. Furthermore, it was performed a literature review in order to collect all existing approaches of service identification, aiming to propose a set of decision models that recommend the most suitable methods according to three SPL scenarios: bottom-up, topdown and hybrid, onde decision model for each scenario. One of the decision models was evaluated through a case study in a medical applications domain, using two approaches classified in the decision model of the top-down scenario. The main contribution of this research is to provide an instrument that can help the service identification stakeholders to choose a suitable method, taking consideration of their SPL scenarios. In addition, these systematic methods facilitate the application of the identification activity. The case study results evaluated some service identification approaches and presented evidence that the methods can be applied in SPL.
8
Ren, Xiaoan. "The method of arbitrary lines in non-linear visco-elasticity." Thesis, University of Westminster, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240413.
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Aras, Ebru. "Characterization Of Skeletal Muscle Lipids In Obese Mice Lines." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614568/index.pdf.
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Obesity becomes an epidemic health problem in developing and developed countries, which arises due to stable life style and increase in the consumption of high fat diets. Obesity is generally accompanied with various clinical disorders, such as insulin resistance, type II diabetes, hypertension, dyslipidemia and cardiovascular diseases.
This study aims to characterize and quantify different lipid classes in longissimus dorsi (LD) and quadriceps (Q) skeletal muscles of control (DBA/2J), obese Berlin fat mouse inbred (BFMI) and Berlin muscle mouse inbred (BMMI) lines, which
display high fat and high muscle content, respectively. These mouse lines were special due to their phenotypes, especially BFMI lines, which displayed spontaneous and strong obesity. These lines, more specifically BFMI860 and BFMI861, were also
special due to their possibility of being an animal model of cardiovascular diseases and metabolic syndrome, since they also displayed insulin resistance. For separation,identification and quantification of various lipids of these lines, a novel method was developed which gives better separation of main lipid classes via using high performance liquid chromatography (HPLC) coupled to an evaporative light scattering detector (ELSD). Addition of triethylamine (TEA) to the solvents being
used, and altering the parameters of HPLC and ELSD instruments, and also the gradient elution, provided a better separation with an enhanced resolution.
This method has been applied to the lipid extracts obtained from longissimus dorsi (LD) and quadriceps (Q) skeletal muscles of control (DBA/2J), obese Berlin fat mouse inbred (BFMI) and Berlin muscle mouse inbred (BMMI). In this method, a binary gradient elution composed of n-Hexane, isopropanol, methanol, acetic acid and triethylamine was applied to the samples. All interested lipid classes, namely triglyceride (TG), cholesteryl ester (CO), cholesterol (C), 1-oleoyl-rac-glycerol (MG), phosphatidylcholine (PC) and cardiolipin (CLPN), all of which have been known to have a role in obesity, insulin resistance, and cardiovascular diseases, were separated, identified and quantified via this novel method. According to the results,
among BFMI lines, BFMI860 and BFMI861 lines and BMMI806, among BMMI lines, are worth to study obesity. Especially, the former ones may also become animal models for cardiovascular diseases and metabolic syndrome.
10
Leonard, Ronald William. "Application of the Monte Carlo method to the estimation of the risk of failure of transmission line insulation." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28496.
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A digital program has been developed which uses the Monte Carlo technique to estimate the risk of failure of transmission line insulation during system switching operations. The effect of overvoltage waveshape on insulation strength is included. A simple electrical system is used to demonstrate the method and to investigate some general aspects of error and parameter sensitivity.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
11
Mbroh, Nana Adjoah. "On the method of lines for singularly perturbed partial differential equations." University of the Western Cape, 2017. http://hdl.handle.net/11394/5679.
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Magister Scientiae - MScMany chemical and physical problems are mathematically described by partial differential equations (PDEs). These PDEs are often highly nonlinear and therefore have no closed form solutions. Thus, it is necessary to recourse to numerical approaches to determine suitable approximations to the solution of such equations. For solutions possessing sharp spatial transitions (such as boundary or interior layers), standard numerical methods have shown limitations as they fail to capture large gradients. The method of lines (MOL) is one of the numerical methods used to solve PDEs. It proceeds by the discretization of all but one dimension leading to systems of ordinary di erential equations. In the case of time-dependent PDEs, the MOL consists of discretizing the spatial derivatives only leaving the time variable continuous. The process results in a system to which a numerical method for initial value problems can be applied. In this project we consider various types of singularly perturbed time-dependent PDEs. For each type, using the MOL, the spatial dimensions will be discretized in many different ways following fitted numerical approaches. Each discretisation will be analysed for stability and convergence. Extensive experiments will be conducted to confirm the analyses.
12
Wang, Rong. "High-order adaptive method of lines for one-dimensional parabolic equations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0019/MQ49461.pdf.
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Shastri, S. Srinivas. "The application of the method of lines to chemical engineering problems." Thesis, Shastri, S. Srinivas (1999) The application of the method of lines to chemical engineering problems. PhD thesis, Murdoch University, 1999. https://researchrepository.murdoch.edu.au/id/eprint/52679/.
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The thesis has addressed three very different problems unified by the application of the method of lines to their solution. The relevance of the thesis lies in the industrial nature of the research that has been carried out.
The moving boundary problem was discussed in the light of industrial applications of induction melting and welding and later extended to the melting of ice. A literature survey suggested that the enthalpy method was well suited to solve moving boundary problems associated with heat transfer. The reduction of a complex moving boundary problem into a sequence of ordinary differential equations is a major contribution of this research to moving boundary problems.
The combination of the method of lines and enthalpy method allows the solution to follow the natural flow of the process. As the solution is time based, it is well suited for the implementation of control strategies.
The work on optimal control has presented a simple strategy to implement a heating trajectory for the heat treatment of aluminium billets. The heater duty compensated for any variation in the furnace air temperature to maintain the billet temperature at the optimal trajectory. The numerical method of lines technique was successful in solving the partial differential equations that described the system.
The hydrogen reduction of nickel has two parts - transport phenomena and particle dynamics. A methodology has been presented to unify these two streams. The high pressure hydrogen reduction process at the Kwinana Nickel Refinery was successfully modelled. There is an excellent agreement between the simulation results and refinery data, to within five percent.
This thesis has clearly demonstrated the applicability of the method of lines to complex engineering problems. In each case a simple and easy to implement methodology has been developed.
14
Sochos, Periklis. "The feature architecture mapping method for feature oriented development of software product lines." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985281928.
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Womble, David Eugene. "The convergence of the method of lines for time dependent free boundary problems." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/29154.
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FRASSON, ANTONIO MANOEL FERREIRA. "STUDY OF THE PROPAGATION CARACTERISTICS OF PLANAR STRUCTURES USING THE METHOD OF LINES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1989. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9853@1.
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O objetivo deste trabalho é apresentar o método das
linhas aplicado ao estudo das características de
propagação em estruturas planares.
Na sua aplicação, discretiza-se variáveis especiais em
um conjunto de linhas perpendiculares as fitas.
Conseqüentemente, equações diferenciais parciais são
reduzidas a equações diferenciais ordinárias com
soluções bem conhecidas. Apesar da aplicação de
diferenças finitas, o Método das Linhas é mais eficiente
em termos de velocidade computacional e uso de memória,
quando comparado com método de diferenças finitas usual.
Algumas estruturas planares em guias retangulares com
três camadas dielétricas foram analisadas e os
resultados comparados com outros métodos.
Nos apêndices mostra-se como é possível implementar
programas com discretização não uniforme, o que aumenta
a eficiência do método, bem como a discretização em duas
direções, o que permite análise de ressoadores de
microondas.
Este trabalho pretende servir como auxilio básico,
podendo ser útil em outros trabalhos empregando o Método
das Linhas.In this work, the Method of Lines applied to the study of the propagation caracteristics of planar structures is presented. In this method, the spacial variables are discretized in several lines orientated in a direction normal to the conductor strips. Then, the partial differential equations are reduced to ordinary differential equations having well known solutions. Although this method uses finite differences, it is much more efficient with respect to computer speed and memory necessary, in comparison to the conventional finite difference method. A few planar structures with three dieletric layers, inside rectangular waveguides were analysed, and the results are compared with those using other reported methods. In the appendix, it is shown how to develop computer programs using non-uniform discretization for the improvement of the efficiency of this method. Also, the discretization in two directions is presented, which is adequate for analysis of microwave resonators. This work is intended as a basic approach to hel in further analysis using the Method of Lines.
17
Petrova, Irina. "Influence of Drying Method on NMR-based Metabolic Profiling of Human Cell Lines." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1565356630902222.
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Lösch, Felix. "Optimization of variability in software product lines a semi-automatic method for visualization, analysis, and restructuring of variability in software product lines." Berlin Logos-Verl, 2008. http://d-nb.info/992075904/04.
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Yin, Yanan. "Calculation of frequency-dependent parameters of underground power cables with finite element method." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/31119.
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In this thesis, the finite element method (FEM) is applied to the calculation of frequency-dependent series impedances and shunt capacitances of underground power cables. The principal equations describing the quasi-magnetic fields and static electric fields are solved with FEM based on the Galerkin technique. The Js method and the loss-energy method are derived to calculate the impedances of a multiconductor system from its field solution, and the energy method and the surface charge method are derived to calculate the capacitances. With a single-core (SC) coaxial cable, the suitability of quadratic isoparametric elements and high-order simplex elements are studied, and a suitable division scheme is suggested for the auto-mesh program.
The conventional FEM with a field truncation boundary is applied to the impedance calculation of buried SC cables. Suitable locations for the field truncation boundary and division schemes in the earth are studied. The results show that rb ≥ 12[symbol omitted] is required to obtain accurate impedances of shallowly buried cables with the conventional FEM. This requires a large solution region in the earth at low frequencies. A new technique based on the perturbation concept is proposed to reduce the solution region in the earth. Comparisons between the results from the conventional FEM and from the proposed technique with a significantly reduced solution region in the earth show good agreement.
In the case studies, the FEM is applied to the parameter calculation of multiphase SC cables, PT cables, sector-shaped cables, and stranded conductors. The numerical results are compared with those from analytical formulas.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
20
Martinho, Lucas Blattner. "Numerical modeling of electromagnetic coupling phenomena in the vicinities of overhead power transmission lines." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-28062016-152807/.
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Les phénomènes de couplage électromagnétique entre les lignes aé- riennes de transmission d\'énergie et des structures voisines sont inévitables, surtout dans les zones densément peuplées. Les effets indésirables découlants de cette proximité sont variés, allant de l\'établissement des tensions dangereuses à l\'apparition de phénomènes de corrosion dus au courant alternatif. L\'étude de cette classe de problèmes est nécessaire pour assurer la sécurité dans les alentours de la zone d\'interaction et aussi pour préserver l\'intégrité des équipements et des dispositifs présents. Cependant, la modélisation compl ète de ce type d\'application implique la représentation tridimensionnelle de la région d\'intérêt et nécessite des méthodes numériques de calcul de champs spécifiques. Dans ces travaux, des problèmes liés à la circulation de courants électriques dans le sol (ou de couplage dit conductif) seront abordés avec la méthode des éléments finis. D\'autres problèmes résultants de la variation temporelle des champs électromagnétiques (ou de couplage dit inductif) seront aussi considérés et traités avec la méthode PEEC (Partial Element Equivalent Circuit) généralisée. Plus précisément, une condition limite particulière sur le potentiel électrique est proposée pour tronquer le domaine de calcul dans l\'analyse par éléments finis des problèmes de couplage conductif et une formulation PEEC complète pour la modélisation de problèmes de couplage inductif est présentée. Des con gurations tests de complexités croissantes sont considérées pour valider les approches précédentes. Ces travaux visent ainsi à apporter une contribution à la modélisation de cette classe de problèmes, qui tendent à devenir communs avec l\'expansion des réseaux électriques.Electromagnetic coupling phenomena between overhead power transmission lines and other nearby structures are inevitable, especially in densely populated areas. The undesired effects resulting from this proximity are manifold and range from the establishment of hazardous potentials to the outbreak of alternate current corrosion phenomena. The study of this class of problems is necessary for ensuring security in the vicinities of the interaction zone and also to preserve the integrity of the equipment and of the devices there present. However, the complete modeling of this type of application requires the three- -dimensional representation of the region of interest and needs specific numerical methods for field computation. In this work, the modeling of problems arising from the flow of electrical currents in the ground (the so-called conductive coupling) will be addressed with the finite element method. Those resulting from the time variation of the electromagnetic fields (the so-called inductive coupling) will be considered as well, and they will be treated with the generalized PEEC (Partial Element Equivalent Circuit) method. More specifically, a special boundary condition on the electric potential is proposed for truncating the computational domain in the finite element analysis of conductive coupling problems, and a complete PEEC formulation for modeling inductive coupling problems is presented. Test configurations of increasing complexities are considered for validating the foregoing approaches. These works aim to provide a contribution to the modeling of this class of problems, which tend to become common with the expansion of power grids.
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Nguyen, Huy Hien. "An Interpolation Method for Obtaining Thermodynamic Properties Near Saturated Liquid and Saturated Vapor Lines." MSSTATE, 2004. http://sun.library.msstate.edu/ETD-db/theses/available/etd-03312004-090452/.
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The two most common approaches used to formulate thermodynamic properties of pure substances are fundamental (or characteristic) equations of state (Helmholtz and Gibbs functions) and a piecemeal approach that is described in Adebiyi and Russell (1992). This thesis neither presents a different method to formulate thermodynamic properties of pure substances nor validates the aforementioned approaches. Rather its purpose is to present a method to generate property tables from existing property packages and a method to facilitate the accurate interpretation of fluid thermodynamic property data from those tables. There are two parts to this thesis. The first part of the thesis shows how efficient and usable property tables were generated, with the minimum number of data points, using an aerospace industry standard property package. The second part describes an innovative interpolation technique that has been developed to properly obtain thermodynamic properties near the saturated liquid and saturated vapor lines.
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Tamilselvan, Prasannavenkatesh. "Bottleneck shifting in production lines: Impact of variability, new detection method and control strategies." Thesis, Wichita State University, 2010. http://hdl.handle.net/10057/3708.
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One of the main causes for degrade in the performance of a production line is bottleneck machine. To improve system performance, bottleneck (BN) is one of the critical factors that need to be addressed. Most of the researchers focus on long term bottlenecks in the system. From other researches, it is evident that detection and elimination of short term BNs is more efficient than long term BNs. Till now, there is no generic method to identify bottlenecks in production lines with and without buffer. Proposed inactive duration method for identification of BNs detects both short term and long term bottlenecks.
In production lines, bottlenecks can be classified into buffer bottlenecks and machine bottlenecks. Machine BNs are mainly due to variability in the system. There is always strong relationship between variability and machine BN. Due to dynamic nature of manufacturing lines, there will be frequent shifting of BN between different machines. In this research, BN characteristics are proposed to analyze the critical nature of BN and BN shifting. In production lines with buffer, buffer bottlenecks are eliminated by placing optimal buffer size before each machine. This thesis presents a two step heuristic procedure for optimal buffer size determination. Case studies were conducted for both production lines with optimal buffer and without buffer. Results from case studies proved that increase in variability increases BN time and BN shifting between different machines.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering.
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Ozkal, Piroglu Sefika. "Analysis Of Coupled Lines In Microwave Printed Circuit Elements." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609047/index.pdf.
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Full wave analysis of microstrip lines at microwave frequencies is performed by using method of moments in conjunction with closed-form spatial domain Green&rsquos functions. The Green&rsquo
s functions are in general Sommerfeld-type integrals which are computationally expensive. To improve the efficiency of the technique, Green&rsquo
s functions are approximated by their closed-forms. Microstrip lines are excited by arbitrarily located current sources and are terminated by complex loads at both ends. Current distributions over microstrip lines are represented by rooftop basis functions. At first step, the current distribution over a single microstrip line is calculated. Next, the calculation of the current distributions over coupled microstrip lines is performed. The technique is then, applied to directional couplers. Using the current distributions obtained by the analysis, the scattering parameters of the structures are evaluated by using Prony&rsquo
s method. The results are compared with the ones gathered by using simulation software tools, CNL/2&trade
and Agilent Advanced Design System&trade
(ADS).
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BASTOS, Jonatas Ferreira. "A multi-method research approach to understand the adoption of software product lines in small and medium-sized enterprises." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/2734.
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Previous issue date: 2011Conselho Nacional de Desenvolvimento Científico e Tecnológico
A abordagem de Linhas de Produtos de Software (SPL) pode ser considerada uma estratégia eficiente para o reuso de software. SPL oferece significativos benefícios econômicos para as empresas, tais como redução de custos, melhoria da qualidade, e redução do tempo de entrega de produtos. SPL baseia-se no reuso sistemático de artefatos, através da exploração de commonalities (pontos em comum), e o gerenciamento de variabilities (pontos de variação) entre os produtos, desenvolvidos sob uma arquitetura comum. No entanto, a percepção das vantagens de SPL tem um custo associado. Elas demandam maturidade nas técnicas de engenharia de software, planejamento e gerenciamento de reuso, adequadas práticas para gerenciamento e desenvolvimento, sendo capaz de lidar com questões organizacionais e de complexidade arquitetural. Na prática, não é relativamente fácil adotar a abordagem de linha de produto. No contexto de pequenas e medias empresas (SMEs), as dificuldades para adoção de linha de produto são ainda maiores, devido a baixa maturidade organizacional e falta de recursos comum a este tipo de organização. Neste contexto, esta dissertação apresenta um conjunto de evidências empíricas sobre a adoção de linhas de produto em pequenas e médias empresas. O conjunto de evidências contribui para o entendimento da adoção de linha de produto em SMEs por documentar barreiras, as melhores práticas existentes, experiências etc., facilitando a adoção da abordagem de SPL no futuro. Esta dissertação apresenta ainda uma abordagem multi-método para pesquisa empírica em engenharia de software, conduzida através da triangulação, combinando diferentes, mas complementares métodos de pesquisa, aumentando desta maneira a disponibilidade de conhecimento empírico na área.
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Toor, Faraz [Verfasser]. "A study of the exponential method of lines for a class of parabolic problems / Faraz Toor." Ulm : Universität Ulm. Fakultät für Mathematik und Wirtschaftswissenschaften, 2013. http://d-nb.info/1030569290/34.
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Dong, K., D. P. Connolly, O. Laghrouche, P. K. Woodward, and Costa P. Alves. "The stiffening of soft soils on railway lines." Elsevier, 2018. https://publish.fid-move.qucosa.de/id/qucosa%3A73234.
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Railway tracks experience elevated rail deflections when the supporting soil is soft and/or the train speed is greater than approximately 50% of the wave propagation velocity in the track-soil system (i.e. the critical velocity). Such vibrations are undesirable, so soil replacement or soil improvement of the natural soil (or alternatively mini-piles or lime-cement treatment) is often used to increase track-ground stiffness prior to line construction. Although areas of existing soft subgrade might be easily identified on a potential new rail route, it is challenging to determine the type and depth of ground remediation required. Therefore, major cost savings can be made by optimising ground replacement/improvement strategies.
This paper presents a numerical railway model, designed for the dynamic analysis of track-ground vibrations induced by high speed rail lines. The model simulates the ground using a thin-layer finite element formulation capable of calculating 3D stresses and strains within the soil during train vehicle passage. The railroad track is modelled using a multi-layered formulation which permits wave propagation in the longitudinal direction, and is coupled with the soil model in the frequency-wavenumber domain. The model is validated using a combination of experimental railway field data, published numerical data and a commercial finite element package. It is shown to predict track and ground behaviour accurately for a range of train speeds.
The railway simulation model is computationally efficient and able to quickly assess dynamic, multi-layered soil response in the presence of ballast and slab track structures. Therefore it is well-suited to analysing the effect of different soil replacement strategies on dynamic track behaviour, which is particularly important when close to critical speed. To show this, three soil-embankment examples are used to compare the effect of different combinations of stiffness improvement (stiffness magnitude and remediation depths up to 5 m) on track behaviour. It is found that improvement strategies must be carefully chosen depending upon the track type and existing subgrade layering configuration. Under certain circumstances, soil improvement can have a negligible effect, or possibly even result in elevated track vibration, which may increase long-term settlement. However, large benefits are possible, and if detailed analysis is performed, it is possible to minimise soil improvement depth with respect to construction cost.
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Kasap, Huseyin. "Investigation Of Stockbridge Dampers For Vibration Control Of Overhead Transmission Lines." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614865/index.pdf.
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This thesis aims to examine the performance of Stockbridge dampers used to suppress aeolian vibrations on overhead transmission lines arising from the wind. In this respect, a computer program, based on the Energy Balance Method, is developed using MATLAB. The developed computer program has also a graphical user interface (GUI), which allows the program to interactively simulate Stockbridge damper performance for vibration control of overhead transmission lines. Field tests results obtained from literature are used in various case studies in order to validate and evaluate the developed software. Moreover, sample Stockbridge damper characterization tests, which then could be introduced to the software, are performed. A custom test fixture is designed due to its unavailability of commercial alternatives in the market. In the design of the test fixture, modal and transmissibility analyses are done by using ANSYS Workbench. To further validate the test setup, transmissibility test is done and consistent results with the transmissibility analyses are observed in the range of expected aeolian vibration frequencies. Finally, the stepped-sine and swept-sine tests are performed with and without damper for the characterization test, where the latter one is performed to eliminate the negative effects of the test setup. Both tests yield almost same damper power dissipation curves.
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Pham, Thi-Kim-Dung. "Development of Correct-by-Construction Software using Product Lines." Thesis, Paris, CNAM, 2017. http://www.theses.fr/2017CNAM1138/document.
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Nous avons commencé la thèse par la littérature d'enquête sur les approches SPLE et CbyC dans l'état de l'art. Sur la base de l'aperçu et des connaissances obtenues, nous avons analysé les problèmes existants et suggéré des moyens de les résoudre pour notre objectif principal. Nous avons proposé dans le chapitre 2 une méthodologie pour développer des lignes de produits afin que les produits générés soient corrects par construction. Notre intention principale est qu'un utilisateur n'a pas besoin de connaître le processus de génération de produit mais peut recevoir un produit final correct en sélectionnant une configuration de fonctionnalité. En utilisant la méthodologie, les produits finaux sont générés automatiquement et leur exactitude est garantie. À la suite de cette proposition, nous sommes passés au chapitre 3 pour définir la langue de FFML qui est utilisé pour l'écriture de modules. Le mécanisme de réutilisation et de modification, défini pour la langue et appliqué à toutes sortes d'artefacts (spécification, code et preuve de précision) réduit l'effort de programmation. Au chapitre 4, nous nous sommes concentrés sur la définition des mécanismes de composition pour la composition des modules FFML et les intégrons à l'outil FFML Product Generator. L'évaluation de notre méthodologie est réalisée par le développement de deux lignes de produits logiciels, le compte bancaire SPL et le SPL de poker, ce dernier étant un peu plus complexe que le premier. Dans l'évaluation, nous avons souligné les avantages et la limitation de notre méthodologieWe began the thesis by survey literature on SPLE and CbyC approaches in the State of the Art. Based on the overview and the insights obtained, we have analyzed the existing problems and suggested ways to solve them for our main goal. We have proposed in Chapter 2 a methodology to develop product lines such that the generated products are correct-by-construction. Our main intention is that a user does not need to know the product generation process but can receive a correct final product from selecting a configuration of features. Using the methodology, the final products are generated automatically and their correctness is guaranteed. Following this proposal, we have moved in Chapter 3 to define the FFML language that is used for writing modules. The reuse and modification mechanism, defined for the language and applied to all kinds of artifacts (specification, code and correctness proof), reduce the programming effort. In Chapter 4, we have focused on defining the composition mechanisms for composing FFML modules and embedded them into the FFML Product Generator tool. The evaluation of our methodology is performed through the development of two software product lines, the Bank Account SPL and the Poker SPL, the latter being a bit more complex than the former. In the evaluation, we have highlighted the advantages and the limitation of our methodology
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Nguyen, Thu Huong. "Strong Stability Preserving Hermite-Birkhoff Time Discretization Methods." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23491.
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The main goal of the thesis is to construct explicit, s-stage, strong-stability-preserving (SSP) Hermite–Birkhoff (HB) time discretization methods of order p with nonnegative coefficients for the integration of hyperbolic conservation laws. The Shu–Osher form and the canonical Shu–Osher form by means of the vector formulation for SSP Runge–Kutta (RK) methods are extended to SSP HB methods. The SSP coefficients of k-step, s-stage methods of order p, HB(k,s,p), as combinations of k-step methods of order (p − 3) with s-stage explicit RK methods of order 4, and k-step methods of order (p-4) with s-stage explicit RK methods of order 5, respectively, for s = 4, 5,..., 10 and p = 4, 5,..., 12, are constructed and compared
with other methods. The good efficiency gains of the new, optimal, SSP HB methods over other SSP
methods, such as Huang’s hybrid methods and RK methods, are numerically shown by means of their effective SSP coefficients and largest effective CFL numbers. The formulae of these new, optimal methods are presented in their Shu–Osher form.
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Chou, Ling-Miao. "A novel hybrid full-wave analysis method for planar transmission lines embedded in multilayered dielectrics : the WH/GSMT /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487779914824785.
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Lábsky, Balázs. "Metody analýzy přenosových struktur v časové oblasti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218020.
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This work deals with techniques of time-domain analysis of interconnects. After a studying crucial issue of time-domain analysis of interconnects methods of modeling and simulation simple interconnects in electrotechnics are described. For transient effect analysis two elementary methods can be used: the state variable method and the FDTD (Finite - Difference Time - Domain) method. The FDTD method can be used to solve partial differential equations in time domain, for instance equations of transmission lines. The method is very effective and delivers satisfactory results in case of linear and non-linear lines with a single “live” conductor. The method can be easily programmed in Matlab.
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Fulford, Andrew Richard Wentworth Stuart M. "Conductor and dielectric property extraction using microstrip tee resonators." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Summer/master's/FULFORD_ANDREW_7.pdf.
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Lin, Chien-Min. "Efficiently computational techniques for solving large-scale electromagnetic problems microstrip interconnects and rough surface scattering /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/5878.
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Preece, Robin. "A probabilistic approach to improving the stability of meshed power networks with embedded HVDC lines." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/a-probabilistic-approach-to-improving-the-stability-of-meshed-power-networks-with-embedded-hvdc-lines(b7e4843f-52b4-4ccf-88ad-48f9195b7270).html.
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This thesis investigates the effects of High Voltage Direct Current (HVDC) lines andmulti-terminal grids on power system small-disturbance stability in the presence ofoperational uncertainties. The main outcome of this research is the comprehensiveprobabilistic assessment of the stability improvements that can be achieved through theuse of supplementary damping control applied to HVDC systems.Power systems are increasingly operated closer to stability boundaries in order toimprove their efficiency and economic value whilst a growing number of conventionalcontrolled power plants are being replaced by stochastic renewable generation sources.The resulting uncertainty in conditions can increase the risk of operational stabilityconcerns and should be thoroughly evaluated. There is also a growing necessity toexplore the potential improvements and challenges created by the introduction of newequipment, such as HVDC systems. In recent years, HVDC systems have become moreeconomically competitive and increasingly flexible, resulting in a proliferation ofprojects. Although primarily installed for power transmission purposes, their flexibilityand controllability can provide further benefits, such as the damping of persistentoscillations in the interconnected networks.This work contributes to a number of areas of power systems research, specificallysurrounding the effects of HVDC systems on the small-disturbance stability oftransmission networks. The application and comprehensive assessment of a Wide AreaMeasurement System (WAMS) based damping controller with various HVDC systemsis completed. The studies performed on a variety of HVDC technology types andconfigurations – as well as differing AC test networks – demonstrate the potential forHVDC-based Power Oscillation Damping (POD). These studies include examinationsof previously unexplored topics such as the effects of available modulation capacity andthe use of voltage source converter multi-terminal HVDC grids for POD. Followingthese investigations, a methodology to probabilistically test the robustness of HVDC based damping controllers is developed. This methodology makes use of classificationtechniques to identify possible mitigation options for power system operators whenperformance is sub-optimal. To reduce the high computational burden associated withthis methodology, the Probabilistic Collocation Method (PCM) is developed in order toefficiently identify the statistical distributions of critical system modes in the presenceof uncertainties. Methods of uncertain parameter reduction based on eigenvaluesensitivity are developed and demonstrated to ensure accurate results when the PCM isused with large test systems. Finally, the concepts and techniques introduced within thethesis are combined to probabilistically design a WAMS-based POD controller morerobust to operational uncertainties. The use of the PCM during the probabilistic designresults in rapid and robust synthesis of HVDC-based POD controllers.
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Maroly, Anupam. "The development of a sensitive method to study volatile organic compounds in gaseous emissions of lung cancer cell lines." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2423.
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The ultimate objective of this research was to develop a low cost, reliable system that
would lead to early detection of lung cancer. Tests involved the quantitation of gaseous
metabolic emissions from immortalized lung cancer cell lines in order to correlate the
chemical markers to be of cancerous origin. The specific aims of the project were the
study of gas emissions in selected cancer cell lines and identification of volatile organic
compounds (VOCs) in them.
Disadvantages of earlier studies were that the measurements were not real time or state
specific so that molecular identification was often inconclusive. Furthermore the methods
of study used in the past were not quantitative, which limited their practicality for
medical applications. We felt the need to prove or disprove these earlier results using a
new technique.
The method we proposed is different and unique when compared to previous methods
because cell lines have not been studied extensively for cancer markers. We have studied
cancer cell lines which are adherent, immortalized cultures originating from primary
tumors obtained from patients with no prior treatment for lung cancer.
We have used an alternative method for the spectrometric analysis and quantitation of the
selected chemical markers. The pre-concentration method involved a Purge and Trap
unit with a thermal desorber where the vapor concentration was enhanced. The
concentrated head space gases were analyzed using a Gas Chromatograph ?? Mass
Spectrometer setup. This setup eliminated the bulky apparatus used in earlier studies. It is
simpler in design and more comprehensive so that external factors such as patient??s diet,
habitat and lifestyle do not contribute to our study of recognition of cancer markers.
Based on the results obtained in the above experiments, a more comprehensive,
inexpensive study of lung cancer related markers could be made.
The first section, after giving an introduction to lung cancer, goes on to explain the
background work done by other researchers on cancer. The third section gives a detailed
explanation of the experimental setup. This is followed by all the tests conducted with
corresponding results. The final section deals with the conclusions drawn from all
experiments.
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Arunachalam, Sasi. "The Role of store operated calcium channels in human carcinoid cell lines." University of Toledo Health Science Campus / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=mco1279216983.
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Lepilliez, Mathieu. "Simulation numérique des ballotements d'ergols dans les réservoirs de satellites en microgravité et à faible nombre de Bond." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30248/document.
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Cette thèse porte sur l'étude des ballotements dans les réservoirs de satellites à poste, lors des phases de manoeuvre à faible accélération. En effet la bulle de gaz d'hélium servant à pressuriser le réservoir se met en mouvement, générant ainsi des perturbations sur la stabilité globale du satellite. Afin de mener à bien cette étude, des méthodes numériques ont été développées, avec une méthode de frontières immergées pour prendre en compte les parois du réservoir.Le code est utilise la méthode Level-Set pour capturer l'interface, et gère les sauts à l'aide de la méthode Ghost-Fluid. Un solveur BlackBox Multigrid est également développé pour améliorer lesperformances de calcul. Une étude est présentée dans le dernier chapitre pour définir quelques lois de comportements en fonction des vitesses et accélérations générées lors des manoeuvresThe core study of this PhD thesis is the sloshing in satellite tanks, during low acceleration maneuvers. Indeed the helium bubble used to pressurize the tank moves, thus generating perturbations on the global stability of the satellite. In order to understand this problem, numerical schemes have been developed, such as an immersed boundary method to model the tank wall. The numerical tool uses a Level-Set function coupled to a Ghost Fluid Method to track the interface and to account for the jump conditions.A BlackBox Multigrid Solver have been developed to improve computational cost. Finally a study is presented in the last chapter to predict the behaviour of the fluids with a varying rotational speed generated during some classical maneuvers
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Brown, Gregory Hippolyte. "Blurred Lines Between Role and Reality: A Phenomenological Study of Acting." Antioch University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1575378494184268.
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Colnago, Marilaine [UNESP]. "Estudo da estabilidade do método das linhas usando a dinâmica de um cabo flexível." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/99833.
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Universidade Estadual Paulista (UNESP)
O estudo de equações diferenciais parciais tem merecido muito destaque nos últimos anos. O fato é que se trata de uma área muito utilizada em vários ramos da Ciência como Matemática, Física e Engenharia. Além disso, permite a modelagem de muitos problemas encontrados em nosso cotidiano e na natureza em geral. Porém, a sua utilização se torna complicada uma vez que, tais equações nem sempre apresentam o que chamamos de solução analítica. Isto só acontece com uma “pequena” classe de equações (ver [19]). Fazse então necessário, buscar outras alternativas para a resolução de tais equações e daí os métodos numéricos de resolução desempenham um papel muito importante. O método das linhas, conhecido como um método de semi-discretização, representa uma alternativa para encontrar tais soluções e tem recebido atenção na atualidade. O presente trabalho, abrange, um estudo do método das linhas em sua forma original, bem como o estudo da estabilidade desse método utilizando a dinâmica de um cabo flexível. O método não foi satisfatório tanto para o cabo inextensível quanto para o cabo extensível, logo após poucos passos no tempo, a solução se deteriorou, representando, ao nosso ver, a instabilidade do método
The study of partial differential equations has received much attention in the recent years. The fact is that this is an area widely used in various branches of science such as Mathematics, Physics and Engineering. Furthermore, it allows the modeling of many problems encountered in our activities and nature in general. However, their use becomes complicated since these equations do not always have what we call analytical solution. This only happens with a “ small” class of equations (see [19]). So, it is necessary to seek other alternatives for solving these equations, hence the numerical resolution methods play an important role. The method of lines, known as a semi-discretization method, represents an alternative to find such solutions and has received attention in the literature. This work includes a study of the method of lines in its original form, as well as to study the stability of this method using the dynamics of a flexible cable. This method was not satisfactory for both the inextensible cable and to extensible cable, after a few steps in time, the solution has deteriorated, representing, in our view, the instability of the method
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Wood, Sandra Jean. "Determination of effective thermal conductivity of media surrounding underground transmission cables." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/17390.
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Harvey, Jeremy Paul. "Oscillatory compressible flow and heat transfer in porous media application to cryocooler regenerators /." Diss., Available online, Georgia Institute of Technology, 2003:, 2003. http://etd.gatech.edu/theses/available/etd-11022003-000618/unrestricted/HarveyJeremyP200312.pdf.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2004.Desai, Prateen V., Committee Chair; Ghiaasiaan, S. Mostafa, Committee Member; Yoda, Minami, Committee Member; Kirkconnell, Carl S., Committee Member; Morris, Jeffrey F., Committee Member. Includes bibliographical references.
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Wassef, Karim N. "Nonlinear transient finite element analysis of conductive and ferromagnetic regions using a surface admittance boundary condition." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/13318.
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Colnago, Marilaine. "Estudo da estabilidade do método das linhas usando a dinâmica de um cabo flexível /." Presidente Prudente : [s.n.], 2012. http://hdl.handle.net/11449/99833.
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Orientador: Messias Meneguette JúniorBanca: Vanessa Avansini Botta Pirani
Banca: Heloisa Helena Marino Silva
Resumo: O estudo de equações diferenciais parciais tem merecido muito destaque nos últimos anos. O fato é que se trata de uma área muito utilizada em vários ramos da Ciência como Matemática, Física e Engenharia. Além disso, permite a modelagem de muitos problemas encontrados em nosso cotidiano e na natureza em geral. Porém, a sua utilização se torna complicada uma vez que, tais equações nem sempre apresentam o que chamamos de solução analítica. Isto só acontece com uma "pequena" classe de equações (ver [19]). Fazse então necessário, buscar outras alternativas para a resolução de tais equações e daí os métodos numéricos de resolução desempenham um papel muito importante. O método das linhas, conhecido como um método de semi-discretização, representa uma alternativa para encontrar tais soluções e tem recebido atenção na atualidade. O presente trabalho, abrange, um estudo do método das linhas em sua forma original, bem como o estudo da estabilidade desse método utilizando a dinâmica de um cabo flexível. O método não foi satisfatório tanto para o cabo inextensível quanto para o cabo extensível, logo após poucos passos no tempo, a solução se deteriorou, representando, ao nosso ver, a instabilidade do método
Abstract: The study of partial differential equations has received much attention in the recent years. The fact is that this is an area widely used in various branches of science such as Mathematics, Physics and Engineering. Furthermore, it allows the modeling of many problems encountered in our activities and nature in general. However, their use becomes complicated since these equations do not always have what we call analytical solution. This only happens with a " small" class of equations (see [19]). So, it is necessary to seek other alternatives for solving these equations, hence the numerical resolution methods play an important role. The method of lines, known as a semi-discretization method, represents an alternative to find such solutions and has received attention in the literature. This work includes a study of the method of lines in its original form, as well as to study the stability of this method using the dynamics of a flexible cable. This method was not satisfactory for both the inextensible cable and to extensible cable, after a few steps in time, the solution has deteriorated, representing, in our view, the instability of the method
Mestre
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Heimann, Felix [Verfasser], and Peter [Akademischer Betreuer] Bastian. "An Unfitted Higher-Order Discontinuous Galerkin Method for Incompressible Two-Phase Flow with Moving Contact Lines / Felix Heimann ; Betreuer: Peter Bastian." Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/117738101X/34.
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Akram, Nadeem. "Photonic devices with MQW active material and waveguide gratings : modelling and characterisation." Doctoral thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-433.
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The research work presented in this thesis deals with modelling, design and characterisation of passive and active optical waveguide devices. The rst part of the thesis is related to algorithm development and numerical modelling of planar optical waveguides and gratings using the Method of Lines (MoL). The basic three-point central-di erence approximation of the δ2=δx2 operator used in the Helmholtz equation is extended to a new ve-point and seven-point approximation with appropriate interface conditions for the TE and TM elds. Di erent structures such as a high-contrast waveguide and a TM surface plasmon mode waveguide are simulated, and improved numerical accuracy for calculating the optical mode and propagation constant is demonstrated. A new fast and stable non-paraxial bi-directional beam propagation method, called Cascading and Doubling algorithm, is derived to model deep gratings with many periods. This algorithm is applied to model a quasi-guided multi-layer anti-resonant reecting optical waveguide (ARROW) grating polarizing structure. In the second part of the thesis, our focus is on active optical devices such as vertical-cavity and edge-emitting lasers. With a view to improve the bandwidth of directly modulated laser, an InGaAsP quantum well with InGaAlAs barrier is studied due to its favorable band o set for hole injection as well as for electron con nement. Quantum wells with di erent barrier bandgap are grown and direct carrier transport measurements are done using time and wavelength resolved photoluminescence upconversion. Semi-insulating regrown Fabry-Perot lasers are manufactured and experimentally evaluated for light-current, optical gain, chirp and small-signal performance. It is shown that the lasers having MQW with shallow bandgap InGaAlAs barrier have improved carrier transport properties, better T0, higher di erential gain and lower chirp. For lateral current injection laser scheme, it is shown that a narrow mesa is important for gain uniformity across the active region. High speed directly modulated DBR lasers are evaluated for analog performance and a record high spurious free dynamic range of 103 dB Hz2=3 for frequencies in the range of 1-19 GHz is demonstrated. Large signal transmission experiment is performed at 40 Gb/s and error free transmission for back-to-back and through 1 km standard single mode ber is achieved.QC 20100827
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Bansal, Anurag. "Finite element simulation of mechanical characterization of composite insulators /." Full text open access at:, 1996. http://content.ohsu.edu/u?/etd,221.
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Wu, Biing-Ru. "RAPID IDENTIFICATION OF ASPERGILLUS SPP. USING A PCR BASED MELTING CURVE METHOD AND CHARACTERIZATION OF A NOVEL CHITINASE IN INSECT RESISTANT MAIZE LINES." MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11032009-141528/.
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Identification of fungal isolates is critical in studying Aspergillus flavus ecology and for developing methods to reduce aflatoxin contamination. In our efforts to track biocontrol applications of the atoxigenic A. flavus K49 (NRRL 30797), we have developed a rapid and accurate classification system for A. flavus based on PCR product melting temperatures (Tm). Using 18 primers and a total of 59 Aspergilli strains, including all 49 representatives of the Georgian peanut Vegetative Compatibility Groups (VCGs), a decision tree Tm flowchart was generated. The decision tree can classify all 59 strains using only 9 of the SSR primers and an average of 3.4 primers for each definitive classification. To confirm the effectiveness of the decision tree for strain identification, unknown samples isolated from experimental fields inoculated with various A. flavus strains in Stoneville, MS were analyzed. Ninety-six percent of the samples could be placed into a VCG using Tm(s) coupled with the decision tree. This dynamic system is an excellent tool for researchers studying biodiversity of A. flavus.
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Guffey, Stephen. "Application of a Numerical Method and Optimal Control Theory to a Partial Differential Equation Model for a Bacterial Infection in a Chronic Wound." TopSCHOLAR®, 2015. https://digitalcommons.wku.edu/theses/1494.
Full textAbstract:
In this work, we study the application both of optimal control techniques and a numerical method to a system of partial differential equations arising from a problem in wound healing. Optimal control theory is a generalization of calculus of variations, as well as the method of Lagrange Multipliers. Both of these techniques have seen prevalent use in the modern theories of Physics, Economics, as well as in the study of Partial Differential Equations. The numerical method we consider is the method of lines, a prominent method for solving partial differential equations. This method uses finite difference schemes to discretize the spatial variable over an N-point mesh, thereby converting each partial differential equation into N ordinary differential equations. These equations can then be solved using numerical routines defined for ordinary differential equations.
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Gomero-Campos, A., R. Mejia-Huayhua, C. Leon-Chavarri, C. Raymundo-Ibañez, and F. Dominguez. "Lean Manufacturing Production Management Model using the Johnson Method Approach to Reduce Delivery Delays for Printing Production Lines in the Digital Graphic Design Industry." Institute of Physics Publishing, 2020. http://hdl.handle.net/10757/656402.
Full textAbstract:
Several factors compel graphic design companies to improve efficiency and competitiveness in their production lines. However, these companies are not prepared to take on this challenge, as they report delays in 20% of their deliveries, caused by high setup times, low machine availability, and poor work scheduling. In this context, this study proposes a new production management model fed by the interaction of lean manufacturing tools and the Johnson scheduling method. This model has been validated by direct application at the SISSA. The results obtained were the reduction of the setup time to 15 minutes, increased machine availability up to 24%, and an efficient scheduling of its tasks. All of these reduced the percentage of delivery delays from 20% to 6%.
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Uygur, Ahmet Bilge. "A Non-iterative Pressure Based Algorithm For The Computation Of Reacting Radiating Flows." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608274/index.pdf.
Full textAbstract:
A non-iterative pressure based algorithm which consists of splitting the solution of momentum energy and species equations into a sequence of predictor-corrector stages
was developed for the simulation of transient reacting radiating flows. A semi-discrete approach called the Method of Lines (MOL) which enables implicit time-integration at
all splitting stages was used for the solution of conservation equations. The solution of elliptic pressure equation for the determination of pressure field was performed by a
multi-grid solver (MUDPACK package). Radiation calculations were carried out by coupling previously developed gray and non-gray radiation models with the algorithm. A first order (global) reaction mechanism was employed to account for the chemistry.
The predictions of the algorithm for the following test cases: i) non-isothermal turbulent pipe flow and ii) laminar methane-air diffusion flamewere benchmarked against experimental data and numerical solutions available in the literature and the capability of the code to predict transient solutions was demonstrated on these test cases. Favorable agreements were obtained for both test cases. The effect of radiation and non-gray treatment of the radiative properties were investigated on the second test case. It was found that incorporation of radiation has significant effect on Temeprature and velocity fields but its effect is limited in species predictions. Executions with both radiation models revealed that the non-gray radiation model considered in the present study produces similar results with the gray model at a considerably higher computational cost. The algorithm developed was found to be an efficient and versatile tool for the timedependent simulation of different flow scenarios constitutes the initial steps towards the computation of transient turbulent combustion.