Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 36 for “"helicoidal"”.
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Thin elastic helicoidal shells
Thesis (Ph.D.) Massachusetts Institute of Technology. Dept. of Mathematics, 1957.
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Circumferentially sinusoidal stress and strain in helicoidal shells.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1970.
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Caracterização microestrutural de juntas soldadas de aço ASTM A-1018 produzidas por soldagem helicoidal em campo
… microestruturais de tubos com costura helicoidal, soldados através do processo a arco submerso em campo. As amostras foram produzidas na empresa MEMPS, que desenvolveu e patenteou um equipamento capaz de realizar a produção de tubos em campo, a Fábrica Móvel de Tubos Helicoidais …
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Self-similar solutions to the mean curvature flow in Euclidean and Minkowski space
… present a new two-parameter family of immersed helicoidal surfaces that rotate/translate with constant velocity under the flow. We look at their limiting behaviour as the pitch of the helicoidal motion goes to 0 and compare it with the limiting behaviour of the classical helicoidal minimal …
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Desenvolvimento de Um Modelo Térmico Mecânico de Uma Mola Helicoidal de Ni-ti Com Efeito Memória de Forma Para Aplicação Numa Máquina de Calor
… térmico e mecânico do comportamento de uma mola helicoidal de Ni-Ti com Efeito Memória de Forma (EMF) para ser empregada em um novo modelo de uma máquina de calor funcional. Esta máquina de calor é acionada por uma mola de Ni-Ti que funciona entre uma fonte quente (373 K) e uma fonte fria (273 …
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Estudio de estrategias de taladrado orbital en el mecanizado de estructuras híbridas de materiales de interés aeronáutico
… aeronáutico frente a operaciones de fresado helicoidal en diferentes configuraciones y estrategias. El interés de esta investigación radica en la tendencia ascendente al uso de estas configuraciones dentro del ensamblaje de estructuras aeronáuticas. Para la automatización de los procesos de …
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Análisis del síndrome doloroso-inestable de la articulación subastragalina mediante un método original
… a través de segmentación ósea, se obtuvo un eje helicoidal para cada paciente a través del movimiento trazado del calcáneo relativo al astrágalo. Se comparó la movilidad del retropié sintomático con el asintomático en cada paciente, así como con la cohorte de voluntarios sanos. Se realizaron …
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Fluidodinamica bifase in condotti elicoidali per applicazioni nucleari
The widespread use of the helicoidal pipes in heat exchangers for air conditioning and refrigeration systems, chemical reactors, and nuclear power plants is due to their heat transfer high efficiency and their compactness. Depending on specific applications of these components, for adequate design …
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Structural colour from a helicoidal cellulose architecture in the secondary cell wall: Optical properties, cell wall composition, structure and morphology of components, and their assembly and interactions.
… of assembling cellulose microfibrils into helicoidal structures. Examples of these architectures can be found in phylogenetically distant species and in different tissues of plants, such as in the endocarp of the fruit of $\textit{Margaritaria nobilis}$, an eudicot, and in the fronds of …
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Superfícies helicoidais com curvatura média constante em M2 × R
… constante não-nula invariantes por movimento helicoidal em M2 × R em que M2 é uma forma espacial bidimensional. No âmbito dessa pesquisa, exploramos o Lema de Bour, que consiste em munir uma superfície com parâmetros especiais (s, t) de modo que sua métrica seja da forma ds2 + U (s)2 dt2 , no …
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The effect of turboprop propulsion on the aerodynamic benefits of formation flight
… the turboprop engines was discretised by shed helicoidal vortex filaments generated by the use of an amalgamation of the propeller theory of Goldstein and Theodorsen. The downwash velocity field of a B747 during cruise, obtained via the use of the VFM Burnham-Hallock (VFM B-H) model programme, …
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Fracture analysis in biomimetic Bouligand architectures
… fiber layers assembled periodically into a helicoidal pattern. Many studies have highlighted the high damage-resistant performance of Bouligand structures and its biomimetic materials. One of the outstanding species with the Bouligand structures is the smashing Mantis Shrimp, …
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Comparative anatomy and evolution of the gastrotrich muscular system
… is arranged as a series of circular, helicoidal, and longitudinal bands around the digestive tract. Circular muscles are generally present in splanchnic and somatic positions. Helicoidal muscles in 50--60° angles are present on the pharynx and intestine of most species. …
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Large area cellulose nanocrystal self-assembly: towards sustainable pigments
… using cellulose nanofibrils organised in helicoidal architectures. Interestingly, similar helicoidal architectures with analogous optical response can be obtained in vitro by self-assembly of cellulose nanocrystals (CNCs). CNCs are rod-like colloids capable of arranging into a liquid …
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Estudo tomográfico convencional e computadorizado da região posterior da mandíbula
… IS2000 COMM-CATR. A tomografia computadoriza helicoidal foi obtida através do equipamento Twin FlashR e as reconstruções ortorradiais, cada uma com 2 mm de espessura, foram realizadas com o softtware Denta CTr. A mandíbulas foram seccionadas nos sítios propostos e todas as imagens, …
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Cellulose photonics: designing functionality and optical appearance of natural materials
… however, some species organise cellulose in helicoidal nano-architectures generating strong iridescent colours. Recent research has shown that cellulose nanocrystals, CNCs, isolated from natural fibres, can spontaneously self-assemble into architectures that resemble the one producing …
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Simulación de muelles
… determinar la constante elástica de un muelle helicoidal utilizando modelos de elementos finitos en 1D y 3D. El objetivo es desarrollar una aplicación que siga una metodología que pueda calcular la constante elástica en función de las propiedades geométricas y mecánicas del muelle. El estudio …
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Investigation of heat recovery and combustion characteristics in small scale combustion chambers
… in a way that the cold reactants flow in a helicoidal channel which surrounds the inner cylinder where combustion stabilized on a porous medium occurs. Combustion products are then recirculated through a second outer helicoidal channel so that the unburnt mixture receives heat from both …
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Análise de estruturas reticuladas pelo método das matrizes de transferência
… are efficient enough in the analysis of archs, helicoidal beams and viaducts transformed in a polygonal form with a great number of bars.
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The self-assembly of chitin nanocrystals into hierarchically structured functional materials
… the self-assembly of ChNCs, and in turn tune the helicoidal nanoarchitecture preserved in the solid state. While the shrimp ChNC system was found to be limited to pitch values ranging from 650 to 4,000 nm in solid state, fungal ChNC suspension could be evaporated to reach helicoidal pitch values …
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