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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of a generalised Schwarz-Christoffel transformation of some problems of steady free surface flow

King, A. C. January 1988 (has links)
No description available.
2

Computational investigation of incompressible airfoil flows at high angles of attack

Mathre, John Mark 12 1900 (has links)
Approved for public release; distribution is unlimited / Cebeci's viscous/inviscid interaction program was applied to the analysis of steady, two dimensional, incompressible flow past four airfoils, the NACA 66₃-018, 0010 (Modified), 4412 and the Wortmann FX 63-137. Detailed comparisons with the available experimental results show that the essential features are correctly modelled, but that significant discrepancies are found in regions of flow separations. / http://archive.org/details/computationalinv00math / Lieutenant, United States Navy
3

[en] COMPUTATIONAL ANALYSIS OF THE STABILITY OF FRACTURED ROCK MASSES / [es] IMPLEMENTACIÓN COMPUTACIONAL PARA EL ESTUDIO DE ESTABILIDAD DE MACIZOS ROCOSOS FRACTURADOS / [pt] IMPLEMENTAÇÕES COMPUTACIONAIS PARA O ESTUDO DA ESTABILIDADE DE MACIÇOS ROCHOSOS FRATURADOS

JULIO ERNESTO MACIAS ALVARENGA 06 September 2001 (has links)
[pt] O presente trabalho apresenta aplicações das técnicas de Relaxação Dinâmica e Análise Limite ao estudo da estabilidade de maciços rochosos fraturados. O maciço é modelado como um meio descontínuo formado por blocos rígidos com deformação concentrada nas juntas. A técnica de Relaxação Dinâmica é usada para a solução do problema de equilíbrio resultante, através do programa BLOCO. As expressões desenvolvidas para a matriz de rigidez tangente, usando o modelo de Barton & Bandis, foram implementadas no programa BLOCO. Exemplos para a validação do algoritmo são apresentados. A partir do trabalho de Faria (1992), foi implementado um procedimento automatizado e otimizado para a solução do problema de Análise Limite em um meio formado por blocos rígidos. O procedimento desenvolvido permitiu a solução de problemas de porte relatados na literatura. / [en] This work presents some applications of the Dynamic Relaxation and Limit Analysis techniques, to the study of the stability of fractured rock masses. Rock mass is modeled as a discontinuum formed by rigid blocks with deformable joints. Dynamic Relaxation was applied to solve the resulting equilibrium problem, using the program BLOCO. Expressions obtained for tangent stiffness matrix, derived from Barton & Bandis model, were implemented into the BLOCO program. In order to extend Faria`s (1992) work, an automatic and optimized procedure, to solve the Limit Analysis problem of a media formed by rigid blocks was implemented. The developed procedure was applied to the study of relatively large dimensions problems, reported in the literature. / [es] Este trabajo presenta aplicaciones de las técnicas de Relajación Dinámica y Análisis Límite al estudio de la estabilidad de macizos rocosos fracturados. EL macizo es modelado como un medio discontinuo formado por bloques rígidos con deformación concentrada en las juntas. La técnica de Relajación Dinámica se utiliza para resolver el problema de equilíbrio resultante, a través del programa BLOQUE. Las expresiones desarrolladas para la matriz de rígidez tangente, usando el modelo de Barton & Bandis, se implementaron en el programa BLOQUE. Se presentan algunos ejemplos para la evaluación del algoritmo. A partir del trabajo de Faria (1992), fue implementado un procedimiento automatizado y optimizado para la solución del problema de Análisis Límite en un medio formado por bloques rígidos. El procedimiento desarrollado permitió resolver problemas de porte relatados en la literatura.
4

A Computational Analysis of Driving Variations in a Distributed Simulated Driving Environment

Yasar, Ansar-Ul-Haque, Jameel, Adeel January 2007 (has links)
<p>This Master thesis report is the research conducted at the Linköping University (LiU) in the Cognitive Engineering group. This report describes and discusses the possible driving variations at T-intersections. In this study we tested how voice based command (GPS) system and traffic lights did influence the driving behavior. This computational study was conducted on a multi user driving simulation environment at Linköping University. A total of 12 groups each consisting of 4 persons participated in this study. The participants also completed a survey on paper with their valuable comments. To study the driving behavior we analyzed the conflict indicators at the Tintersection. We selected Post Encroachment Time (PET), speed and acceleration as good conflict indicators.</p>
5

Role of Amylase in Ovarian Cancer

Mohamed, Mai 05 July 2017 (has links)
Ovarian cancer (OC) accounts for 4% of all cancer cases and 4.2% of all cancer deaths worldwide. OC is the most lethal gynecological cancer because it lacks early disease symptoms and does not have a specific diagnostic marker. As a result, more than 70% of OC patients are diagnosed in later stages when the disease has already metastasized and the 5-year survival rate has decreased to less than 20% compared with approximately 90% survival for women diagnosed with early stage disease. Therefore, I initiated my studies with a computational analysis of the 27 most commonly reported literature-derived ovarian cancer (LDOC) protein biomarkers. I found that LDOC protein biomarkers share many biochemical features including a preponderance for a stable protein structure, the ability to be secreted, and functionality related to extracellular matrix (ECM) modification, immune response and/or energy production. Subsequently, I analyzed the human proteome to identify proteins that also share these biochemical features. Of the 70,616 proteins in the human proteome, 683 proteins were found to have similar biochemical features to the 27 LDOC proteins. I also identified a subset of 21 potential additional protein regulators of ovarian cancer (APROC) that interact with LDOCs. Three of the APROCs identified were amylase proteins AMY1A, AMY2A, and AMY2B which cleaves alpha 1, 4-glycosidic bonds in polysaccharides. Amylase is reportedly overexpressed in and secreted by ovarian tumors but its functional contribution to OC remains unknown[1]. In this thesis, I posit that amylase contributes to OC invasion. I initiated my studies by computational characterizing the different amylase isozymes to predict which amylase isozyme(s) is most likely overexpressed in and contributory to OC invasion. I found that AMY1 and AMY2B have unique regions of disorder and unique phosphorylation sites indicating that AMY1 and AMY2B would be more likely to interact with other proteins, and to be easily secreted. Using OC patient serum samples, I was able to validate AMY1 and AMY2B overexpression by western immunoblotting. I then developed an in vitro model system to study the molecular contribution of amylase to OC invasion using normal ovarian surface epithelial (IOSE) and OC cell lines. I showed that OC cells generally overexpress and secrete metabolically active amylase isozymes AMY1 and AMY2B. Abrogating amylase activity using siRNA silencing technology decreased the capacity of OC cells to invade collagen coated Boyden chambers and increased sulfated glycosaminoglycans (sGAG) production. Since a survey of OC cell lines indicated that cancer cells have a bulkier glycocalyx compared to IOSE cells and immunogold labeling studies indicated the presence of amylase within the immediate OC microenvironment, my data suggest that, by cleaving alpha 1, 4-glycosidic bonds in glycoconjugates present within ECM, amylase may remodel the ECM to promote an invasive cancer phenotype. Amylase is therefore a target for therapeutic intervention in OC patients with hyperamylasemia. I established Spirulina, a dietary supplement, as a novel transcriptional inhibitor of amylase. Spirulina inhibited amylase expression in OC cell lines at both the message and protein levels. Spirulina reduced OC cell invasion and migration in vitro, putatively by decreasing amylase expression.
6

Computational Analysis of Asphalt Binder based on Phase Field Method

Hou, Yue 29 April 2014 (has links)
The mechanical performance evaluation of asphalt binder has always been a challenging issue for pavement engineers. Recently, the Phase Field Method (PFM) has emerged as a powerful computational tool to simulate the microstructure evolution of asphalt binder. PFM analyzes the structure from the free energy aspect and can provide a view of the whole microstructure evolution process. In this dissertation, asphalt binder performance is analyzed by PFM in three aspects: first, the relationship between asphalt chemistry and performance is investigated. The components of asphalt are simplified to three: asphaltene, resin and oil. Simulation results show that phase separation will occur under certain thermal conditions and result in an uneven distribution of residual thermal stress. Second, asphalt cracking is analyzed by PFM. The traditional approach to analyze crack propagation is Classic Fracture Mechanics first proposed by Griffith, which needs to clearly depict the crack front conditions and may cause complex cracking topologies. PFM describes the microstructure using a phase-field variable which assumes positive one in the intact solid and negative one in the crack void. The fracture toughness is modeled as the surface energy stored in the diffuse interface between the intact solid and crack void. To account for the growth of cracks, a non-conserved Allen-Cahn equation is adopted to evolve the phase-field variable. The energy based formulation of the phase-field method handles the competition between the growth of surface energy and release of elastic energy in a natural way: the crack propagation is a result of the energy minimization in the direction of the steepest descent. Both the linear elasticity and phase-field equation are solved in a unified finite element frame work, which is implemented in the commercial software COMSOL. Different crack mode simulations are performed for validation. It was discovered that the onset of crack propagation agrees very well with the Griffith criterion and experimental results. Third, asphalt self-healing phenomenon is studied based on the Atomic Force Microscopy (AFM) technology. The self-healing mechanism is simulated in two ways: thermodynamic approach and mechanical approach. Cahn-Hilliard dynamics and Allen-Cahn dynamics are adopted, respectively. / Ph. D.
7

Boulení delaminovaných kompozitních desek / Buckling and Postbuckling of Delaminated Composite Plates

Obdržálek, Vít January 2010 (has links)
Chování laminátových desek namáhaných na tlak či na smyk může být výrazně ovlivněno přítomností delaminací, tedy oblastí, kde je porušena vazba mezi sousedními vrstvami. Cílem této práce je rozšířit znalosti o chování delaminovaných desek, a to především o chování desek s větším počtem delaminací a desek s delaminacemi libovolného tvaru, neboť taková podoba porušení laminátu více odpovídá poškození vznikajícího v důsledku nízkorychlostního dopadu cizího tělesa na laminátovou desku. Disertační práce se skládá ze tří hlavních částí. V první části jsou stručně nastíněny postupy využívané při analýze boulení delaminovaných desek a jsou diskutována omezení těchto analýz. Dále jsou v této části shrnuty hlavní poznatky o boulení delaminovaných desek. V druhé části práce je popsán výpočtový model použitý v rámci disertační práce pro analýzu boulení delaminovaných desek. Schopnost modelu předpovědět chování delaminovaných desek je pak dokumentována na několika ověřovacích úlohách. Třetí část disertační práce se skládá ze tří samostatných studií chování desek s několika delaminacemi eliptického či kruhového tvaru a jedné studie zabývající se možností náhrady obecného tvaru delaminace kruhem či elipsou. Je probírán vliv řady parametrů na chování delaminovaných desek, konkrétně vliv orientace vrstev laminátu a dále vliv počtu, tvaru, orientace a umístění delaminací. Na základě těchto studií jsou pak zformulována doporučení ohledně postupu při posuzování únosnosti delaminovaných konstrukcí.
8

A Computational Analysis of Driving Variations in a Distributed Simulated Driving Environment

Yasar, Ansar-Ul-Haque, Jameel, Adeel January 2007 (has links)
This Master thesis report is the research conducted at the Linköping University (LiU) in the Cognitive Engineering group. This report describes and discusses the possible driving variations at T-intersections. In this study we tested how voice based command (GPS) system and traffic lights did influence the driving behavior. This computational study was conducted on a multi user driving simulation environment at Linköping University. A total of 12 groups each consisting of 4 persons participated in this study. The participants also completed a survey on paper with their valuable comments. To study the driving behavior we analyzed the conflict indicators at the Tintersection. We selected Post Encroachment Time (PET), speed and acceleration as good conflict indicators.
9

[en] PERFORMANCE OF A NEW CONSTITUTIVE EQUATION FOR NON NEWTONIAN LIQUIDS / [pt] DESEMPENHO DE UMA NOVA EQUAÇÃO CONSTITUTIVA PARA LÍQUIDOS NÃO NEWTONIANOS

RONEY LEON THOMPSON 13 January 2012 (has links)
[pt] Materiais não Newtonianos reagem de maneira diferente quando expostos a esforços cisalhantes ou extensionais. Uma equação constitutiva em que a tensão é função não só da taxa de deformação, mas também do tipo de escoamento é proposta e analisada teoricamente. Ela combina as informações obtidas em cisalhamento, extensão e movimento de corpo rígido em todas as regiões de um escoamento complexo. Esta equação é testada em códigos numéricos para duas geométricas axissimétricas diferentes: a contração abrupta 4:1 e o canal convergente R (2) z = C. Ambas as geometrias têm sido usadas para efetuar medições da viscosidade extensional. Para validação do modelo, foi construída uma seção de testes com uma contração abrupta 4:1. Foram feitos experimentos com fluidos Newtonianos e viscoelásticos utilizando a técnica de Velocimetria por Imagens de Partículas para determinação do campo de velocidade. / [en] Non-Newtonian materials exhibit different behavior if submitted to shear or extension. A constitutive equation in wich the stress is a function not only of the rate of deformation, but also of the type of the flow is proposed and analyzed theorecticaly. It combines information obtained in shear, extension and rigid body motion in all regions of a complex flow. This equation is tested with numerical codes for two different axissymmetrical geometries, namely, the 4:1 abrupt contraction and the R(2)z=C convergent channel. Both geometries have been employed to measure the extensional viscosity. In order to validate the model, a test section was buit with a 4:1 contraction. Newtonian and viscoelastic fluids were tested using the Particle Image Velocimetry technique to determine the velocity field.
10

Harmonic Regional Theory: harmonic process, spatial metaphor, and post-Schenkerian epistemologies of tonal structure

Davis, Harrison G. 31 August 2022 (has links)
A theory of harmony plays a determinant role in the epistemology of tonal structure in music of the common practice, a fact that Schenkerian tonal theorists have long struggled to account for because of the polemical denials issued by Heinrich Schenker regarding the role that harmonic concepts derived from Rameau play in his theoretical frameworks (Schenker [1930] 2014). Attempts have been made recently to rectify the incongruity between Schenker’s uncompromisingly monist musical philosophy and the often-unspoken harmonic premises his ideas rely on (Yust 2015, 2018), but many aspects of how theories of functional harmony relate to the hierarchical structuration of musical time through prolongational processes remain undefined and underexamined. In this thesis, I fill in the lacuna of harmonic accounts in post-Schenkerian frameworks of tonal structure through Harmonic Regional Theory, which defines tonal harmonic process as a containment hierarchy of timespans. Using this framework, I outline a discovery process for properties of tonal stability (Yust 2018, 32) possessed by events and prolongational processes that understands these qualities as the product of stabilizing “forces” (Larson 2012) propagated by the structural influence harmonic-regional “fields” (Quinn 2020). The result is an epistemic model with tremendous analytical utility in both formal and informal analyses of tonal structure, the proof-of-concept for which is provided through the implementation of harmonic-regional theory in an automated analysis of tonal-melodic structure in Beethoven, op. 13, ii.

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