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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.
71

Vliv procesních podmínek a materiálu na mezní tvařitelnost zadaného dílce / Influences of process parameters and material on technological forming limits of given componenet

Exnerová, Jitka January 2015 (has links)
Master s thesis is focused on flaring of tubes endings. There are also mentioned theoretical pieces of knowledge which relate to tubes endings by a flat edge and a cone. The following experiments performed with the own material and tools made by the author s design. Experiments in the production of the flat collar led to the speedy rotation of the sample ending. Experiments with the conical ending brought valuable results from the point of view of comparison of theoretical and measured powers, distribution of thicknesses and utilization of the deformation web to set voltage-deformation state. The dimension excent of the conical ending was limited by the formation of buckling in the cylindrical part of the tube.
72

Stress and failure analysis of thick-walled conical composite rotors

Hufenbach, W., Gude, M., Zhou, B., Kroll, L. 04 June 2019 (has links)
The high specific strength and stiffness of composite materials, as well as the possibility of creating a load-adapted property profile of them are ideally suited for the design of high-speed lightweight rotors. With respect to a load-adapted reinforcement structure of composite rotors, the rotor geometry has a significant influence on the optimum fibre orientation. In the case of conical rotors—the structural behaviour is strongly influenced by centrifugally induced bending effects in the rotor structure, which cause complex three-dimensional stress states in combination with the ordinary tangential and radial stresses. For analysis of the resulting complex stress states, an analytical method has been developed and verified numerically as well as experimentally. The novel method presented here is the basis for a realistic failure analysis and, in particular, serves as an efficient tool for extensive parameter studies and optimizations within the design process.
73

An in vitro assessment of the bacterial sealing capacity of narrow diameter implants with Morse-taper abutment connections.

Alriyahi, Mubarak January 2020 (has links)
Magister Scientiae Dentium - MSc(Dent) / Lack of appropriate bone thickness is a common clinical limitation for tooth replacement, often requiring narrow implants, which have shown better results when combined with Morse taper connections. Little is known about the sealing of the abutment-implant interface of narrow implants with Morse taper connections against oral bacteria.
74

Surjectivity of a Gluing for Stable T2-cones in Special Lagrangian Geometry / スペシャルラグランジュ幾何における安定T2錐に対する張り合わせの全射性

Imagi, Yohsuke 23 May 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18444号 / 理博第4004号 / 新制||理||1577(附属図書館) / 31322 / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)教授 加藤 毅, 教授 堤 誉志雄, 教授 小野 薫 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
75

Conical Intersections and Avoided Crossings of Electronic Energy Levels

Gamble, Stephanie Nicole 14 January 2021 (has links)
We study the unique phenomena which occur in certain systems characterized by the crossing or avoided crossing of two electronic eigenvalues. First, an example problem will be investigated for a given Hamiltonian resulting in a codimension 1 crossing by implementing results by Hagedorn from 1994. Then we perturb the Hamiltonian to study the system for the corresponding avoided crossing by implementing results by Hagedorn and Joye from 1998. The results from these demonstrate the behavior which occurs at a codimension 1 crossing and avoided crossing and illustrates the differences. These solutions may also be used in further studies with Herman-Kluk propagation and more. Secondly, we study codimension 2 crossings by considering a more general type of wave packet. We focus on the case of Schrödinger equation but our methods are general enough to be adapted to other systems with the geometric conditions therein. The motivation comes from the construction of surface hopping algorithms giving an approximation of the solution of a system of Schrödinger equations coupled by a potential admitting a conical intersection, in the spirit of Herman-Kluk approximation (in close relation with frozen/thawed approximations). Our main Theorem gives explicit transition formulas for the profiles when passing through a conical crossing point, including precise computation of the transformation of the phase and its proof is based on a normal form approach. / Doctor of Philosophy / We study energies of molecular systems in which special circumstances occur. In particular, when these energies intersect, or come close to intersecting. These phenomena give rise to unique physics which allows special reactions to occur and are thus of interest to study. We study one example of a more specific type of energy level crossing and avoided crossing, and then consider another type of crossing in a more general setting. We find solutions for these systems to draw our results from.
76

Bending Moments and Deformations of Conical Shell on Euler-Winkler Elastic Foundation.

Chung, Kit Man Peter January 1981 (has links)
<p> Various analytical methods for studying the behaviour of shallow conical shells on Euler-Winkler elastic foundation are presented. </p> <p> To account for the nature of concrete and the geometric properties of the shallow conical shell, Poisson's ratio and certain radial and circumferential deformations of the middle surface are neglected in deriving the basic differential equation. Analytical methods employed in the solution of this shell problem are the GECKELER and asymptotic types of approximations. </p> <p> The presentations of various methods of analysis are made for a representative case of dimensions and loadings of the conical shell to make them as applicable as possible to the cases of thin conical shell commonly encountered in industry. </p> <p> The shell structure studied is a tank in the form of a rotationally symmetrical cylindrical shell supported by a shallow conical shell foundation. The construction joint between the conical shell and the cylindrical shell is either monolithic or hinged. </p> <p> The analytical results of this water tank supported on Euler-Winkler elastic foundation are compared with the corresponding findings of W. Flügge, who assumed a uniform soil bearing pressure acting on the conical shell structure. </p> The method of analysis which possesses obvious advantages over the other methods studied is selected to examine the effect of different elastic stiffness coefficients of the soil. The validity of simplifying the soil bearing pressure to a uniform distribution by most designers can consequently be studied by comparing it to the bearing pressures of an ideal elastic soil which is postulated to react to its deformation like a bed of independent elastic springs. </p> / Thesis / Master of Engineering (ME)
77

Computational Investigation of the Photoisomerization of Novel N-Alkylated Indanylidene Pyrroline Biomimetic Switches

Ryazantsev, Mikhail N. 19 August 2010 (has links)
No description available.
78

On Complete Non-compact Ricci-flat Cohomogeneity One Manifolds

Zhou, Cong 10 1900 (has links)
<p>We present an alternative proof of the existence theorem of B\"ohm using ideas from the study of gradient Ricci solitons on the multiple warped product cohomogeneity one manifolds by Dancer and Wang. We conclude that the complete Ricci-flat metric converges to a Ricci-flat cone. Also, starting from a $4n$-dimensional $\mathbb{H}P^{n}$ base space, we construct numerical Ricci-flat metrics of cohomogeneity one in ($4n+3$) dimensions whose level surfaces are $\mathbb{C}P^{2n+1}$. We show the local Ricci-flat solution is unique (up to homothety). The numerical results suggest that they all converge to Ricci-flat Ziller cone metrics even if $n=2$.</p> / Master of Science (MSc)
79

Conical Shock Wave Turbulent Boundary Layer Interactions In A Circular Test Section At Mach 2.5

Sasson, Jonathan 23 May 2022 (has links)
No description available.
80

Torção Analítica e extensões para o Teorema de Cheeger Müller. / Analytic Torsion and extensions for the Cheeger Müller theorem

Hartmann Júnior, Luiz Roberto 10 December 2009 (has links)
Estudamos a Torção Analítica para variedades com bordo e ainda com singuaridades do tipo cônico, mais especificamente, para um cone métrico limitado, com o propósito de investigar a extensão natural do Teorema de Cheeger Müller para tais espaços. Começamos determinando a Torção Analítica do disco e de variedades com o bordo totalmente geodésico, por meio de ferramentas geométricas desenvolvidas por J. Brüning e X. Ma. Posteriormente, usando ferramentas analíticas desenvolvidas por M. Spreafico, determinamos a Torção Analítica do cone sobre uma esfera de dimensão ímpar e provamos um teorema do tipo Cheeger Müller para este espaço. Mais ainda, provamos que o resualto de J. Brüning e X. Ma estende para o cone sobre uma esfera de dimensão ímpar / We study for Analytic Torsion of manifolds with boundary and also with conical singularities , more specifically, for a finite metric cone, with the purpose of investing the natural extension of the Cheeger Müller theorem for such spaces. we start by computing the Analytic Torsion of an any dimensional disc and of a manifold with totally boundary, by using geometric tools development by J. Brüning and X. Ma. Then, by using analytic tools development by M. Spreafico, we determine the Analytic Torsion of a cone over an odd dimensional sphere and we prove a theorem of Cheeger Müller type space. Moreover, we prove that the result of J. Brüning and X. Ma extends to the cone over an odd dimensional sphere

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