• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 116
  • 43
  • 34
  • 9
  • 9
  • 9
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 282
  • 119
  • 118
  • 105
  • 105
  • 104
  • 97
  • 87
  • 80
  • 58
  • 56
  • 54
  • 49
  • 43
  • 43
  • 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.
41

A Biomechanical Evaluation of a Novel Surgical Reconstruction Technique of the Ulnar Collateral Ligament of the Elbow Joint

Williams, Nicole 10 July 2008 (has links)
The objective of this thesis is to biomechanically evaluate a novel Double bundle technique for UCL reconstruction designed to accelerate recovery time and minimize gap formation. Excluding UCL surgery, ligament reconstruction procedures typically require an average of 6 months of recovery time. UCL reconstructive surgery requires approximately 1-2 years of recovery time. Valgus instability of the elbow is characterized by attenuation, or frank rupture of the UCL from repetitive and excessive valgus loads. This research compared the valgus stability, gap formation, and ultimate strength that resulted from the cyclic valgus loading at 30 ° of flexion of 3 techniques for reconstruction of the UCL: the Jobe, Docking, and a novel Double bundle procedure. A servocontrolled materials testing machine applied a cyclic valgus load to white cortical Sawbones elbow complex models while a 3D electromagnetic motion tracking system recorded the valgus displacement of the UCL reconstructions. The valgus stability, gap formation, and ultimate strength were measured at 50, 100, 200 and 600 cycles or the cycle at which failure occurred. The mean peak load to failure was 30N for the Jobe reconstructions, and 50N for both the Docking and Double bundle reconstructions. Both the Docking and the Double bundle reconstructions sustained a higher load to failure than the Jobe reconstruction. None of the separate univariate ANOVAs of the biomechanical parameters of each reconstruction were statistically significant. Although there was no statistically significant difference, a small standard deviation in all measured values indicated consistency in testing methodology. The power or sample size is not high enough to state with confidence that statistically there is no difference.
42

Destructive Testing and Finite-Element Modeling of Full-Scale Bridge Sections Containing Precast Deck Panels

Brackus, Travis R. 01 December 2010 (has links)
Full-depth, precast panel deck systems are becoming more common in bridge installation and repair. The objective of these systems is to achieve the performance of cast-in-place systems while simultaneously saving time and money. The structural behavior of these systems has been the subject of scrutiny in recent research. The Utah Department of Transportation demolished a steel I-girder bridge containing a precast panel deck system and provided two full-scale specimens for this project. Destructive testing was performed at Utah State University on the specimens to investigate three failure modes: flexural, beam shear, and punching shear. Finite-element models were created using ANSYS software to replicate experimental behavior. Overall, it was found that the elastic, post-elastic, and ultimate behavior of the full-scale bridge sections containing precast panel deck systems can be accurately predicted in analytical models. Another aspect of this project was to investigate changes in dynamic behavior as the system was subjected to flexural yield and failure. Point loads were applied and removed in increments, and dynamic testing was conducted at each load level. It was found that significant damage is somewhat noticeable by monitoring the changes in natural frequencies.
43

Theology, Spirituality, and the Academic Study of Religion in Public Universities

Saunders, Don 02 April 2009 (has links)
This thesis examines whether the secular institutions of American higher education should address students questions of meaning, purpose, wisdom, and human destiny. That is, it investigates the place of the normative analysis of religious experience and behavior within the public university. I use the work of Ninian Smart, Russell T. McCutcheon and Ivan Strenski to illustrate the case against the inclusion of theology and spirituality in the academic study of religion. In their view, theology is at best an artifact, like ritual or religious art and not an academic discipline. Conversely, I use the work of Paul Tillich, John Dunne, and Darrell Fasching to argue for the emergence of an academic theology that can play an important role in the contemporary university. In their view, theology and spirituality address the questions appropriately raised by the humanities, and can be done as long as confessional and apologetic strategies are rejected. I will show how their theories help us understand the nature of the academic study of religion to be inclusive of theology and spirituality, and so respond constructively to the negative views of Smart, McCutcheon and Strenski. My thesis is that, contrary to Smart, McCutcheon and Strenski, theology and spirituality are essential to the academic study and teaching of comparative religions in state universities. If higher education is to achieve the ideals of a liberal arts education and to offer more than the aims of a technical-vocational college curriculum, I maintain that the university education should address students' questions of meaning, purpose, wisdom, and human destiny and not just their need for technical skills. This should be offered under the umbrella of the humanities, including the religious studies department and is best represented in an academic theology that can inspire students to live a life that facilitates a cross-cultural and inter-religious ethic of human dignity.
44

Ultimate strength analysis of stiffened steel and aluminium panels using semi-analytical methods

Byklum, Eirik January 2002 (has links)
<p>Buckling and postbuckling of plates and stiffened panels are considered. Computational models for direct calculation of the response are developed using large deflection plate theory and energy principles. Deflections are represented by trigonometric functions. All combinations of biaxial in-plane compression or tension, shear, and lateral pressure are included in the formulations. The procedure is semi-analytical in the sense that the incremental equilibrium equations are derived analytically, while a numerical method is used for solving the equation systems, and for incrementation of the solution.</p><p>Unstiffened plate models are developed both for the simply supported case and for the clamped case. For the simply supported case the material types considered are isotropic elastic, orthotropic elastic, and elastic-plastic. Two models are developed for analysis of local buckling of stiffened plates, one for open profiles and one for closed profiles. A global buckling model for stiffened panels is developed by considering the panel as a plate with general anisotropic stiffness. The stiffness coefficients are input from the local analysis. Two models are developed for combined local and global buckling, in order to account for interaction between local and global deflection. The first is for a single stiffened plate, and uses a column approach. The second is for a stiffened panel with several stiffeners.</p><p>Numerical results are calculated for a variety of plate and stiffener geometries for verification of the proposed model, and comparison is made with nonlinear finite element methods. Some examples are presented. For all models, the response in the elastic region is well predicted compared with the finite element method results. Also, the efficiency of the calculations is very high. Estimates of ultimate strength are found using first yield as a collapse criterion. In most cases, this leads to conservative results compared to predictions from finite element calculations. </p>
45

Ultimate strength analysis of stiffened steel and aluminium panels using semi-analytical methods

Byklum, Eirik January 2002 (has links)
Buckling and postbuckling of plates and stiffened panels are considered. Computational models for direct calculation of the response are developed using large deflection plate theory and energy principles. Deflections are represented by trigonometric functions. All combinations of biaxial in-plane compression or tension, shear, and lateral pressure are included in the formulations. The procedure is semi-analytical in the sense that the incremental equilibrium equations are derived analytically, while a numerical method is used for solving the equation systems, and for incrementation of the solution. Unstiffened plate models are developed both for the simply supported case and for the clamped case. For the simply supported case the material types considered are isotropic elastic, orthotropic elastic, and elastic-plastic. Two models are developed for analysis of local buckling of stiffened plates, one for open profiles and one for closed profiles. A global buckling model for stiffened panels is developed by considering the panel as a plate with general anisotropic stiffness. The stiffness coefficients are input from the local analysis. Two models are developed for combined local and global buckling, in order to account for interaction between local and global deflection. The first is for a single stiffened plate, and uses a column approach. The second is for a stiffened panel with several stiffeners. Numerical results are calculated for a variety of plate and stiffener geometries for verification of the proposed model, and comparison is made with nonlinear finite element methods. Some examples are presented. For all models, the response in the elastic region is well predicted compared with the finite element method results. Also, the efficiency of the calculations is very high. Estimates of ultimate strength are found using first yield as a collapse criterion. In most cases, this leads to conservative results compared to predictions from finite element calculations.
46

An Attempt To Define Nothingness And A Philosophical Analysis Of The Ultimate Why Question: Why Is There Something Rather Than Nothing?

Turkay, Kemal 01 September 2012 (has links) (PDF)
The main objective of this study is to make a comprehensive analysis of the question &ldquo / Why is there something rather than nothing?&rdquo / , which is one of the major questions of metaphysics, and to find a plausible answer at the end, if it is possible. To begin this analysis, a clarification of what we understand by this question is needed first. For the clarification, a definition of &lsquo / nothingness&rsquo / will be sought. Afterwards, the motivation for us to ask this question, the significance of it, and the content of it will be investigated. This investigation will help us concentrate on and discuss within the framework of causation and necessity our understanding of &ldquo / contingent beings&rdquo / and &ldquo / nothingness&rdquo / . Two main approaches sought to answer this question till now are by theists and physicists. Those approaches will be discussed and compared. And at the end of the comparative analysis of these two approaches, a metaphysical approach which will be a layer of them will be sought.
47

鋼製橋脚の動的耐震照査法に関する検討

MORISHITA, Kunihiro, 森下, 邦宏, 宇佐美, 勉, USAMI, Tsutomu, 阪野, 祟人, BANNO, Takahito, 葛西, 昭, KASAI, Akira 07 1900 (has links)
No description available.
48

Sportfans, sociala medier &amp; UFC : En studie om sociala mediers inverkan på fandom

Mai, Lam, Hällström, Fabian January 2011 (has links)
We aim to develop knowledge of how new technology, in this case social media, can contribute to how sports fans interact with their idols. Therefore our framing of a question is to present how fans experience their contact with mixed martial arts (MMA) &amp; ultimate fighting championship (UFC) through social media platforms. To specify our study, we also have a supplement question with in which way sports fans uses social media.We have chosen to conduct a qualitative study consisting of interviews and data observations of websites, related to the organization UFC, to approach our main question. We have interviewed nine randomly selected people with one common interest - MMA/UFC. With an implant of theories, consisting of social media, fandom and lurking, on the result of the interview and website data, we try to come closer to a conclusion for our intention with this thesis.Our conclusion is that the interviewed fans express that through the usage of social media, they feel like they have come closer to UFC. They have developed a deeper knowledge about the sport, the members and other fans that shares the same interest. Most of our respondents have a lurking attitude towards the social media usage, which means that they are more like observers and soak in the information and media material. They are active in the searching of material related to UFC, but they are not active in the way of contributing with comments, discussions or material.
49

Dynamic Strength of Porcine Arteries

Fan, Jinwu 15 November 2007 (has links)
The failure behavior of collagenous soft tissues is important for clinical problems of plaque rupture and trauma. Cyclic tests require high frequencies that may affect the strength properties of the soft tissues. Experimental results of mechanical response of blood vessels to physiologic loads can be used to model and predict plaque rupture and direct medical therapy or surgical intervention. The goal of the study is to measure the mechanical failure properties of arteries to determine if they are strain rate and cycle dependant and to measure the progressive damage of arteries with time dependent loading. Ring specimens of porcine carotid arteries were preconditioned and then pulled to failure. In all cases, the intima broke first. Ultimate stress increased as a weak function of increasing strain rates. The ultimate stress at 100 mm/s was 4.54 MPa, greater than the 3.26 MPa at 0.1 mm/s. Strain rates between 1 and 100 mm/s correspond to a cyclic frequency of 0.5 Hz to 5 Hz for fatigue testing. In contrast, ultimate strain in arteries was independent of strain rate over the range tested. The creep tests showed a logarithmic relationship between stress magnitude and stress duration for this soft tissue. The creep testing indicates that damage is accumulating above certain threshold stress levels. The values of ultimate strength showed a 35% increase after 10,000 cycling loading. In contrast, the ultimate strain had a 13% decrease after cycling and the difference was statistically significant with p=0.018. The testing results showed that there were no significant differences on strength among fresh arteries and arteries stored at 5¡ã C for up to two weeks. The test results may be useful for developing a mathematical model to predict the behavior of arterial soft tissues and may be extended to estimate fracture and fatigue in the atherosclerotic plaque cap.
50

Analytical Modeling of Wood Frame Shear Walls Subjected to Vertical Load

Nguyendinh, Hai 2011 May 1900 (has links)
A nonlinear automated parameter fitted analytical model that numerically predicts the load-displacement response of wood frame shear walls subjected to static monotonic loading with and without vertical load is presented. This analytical model referred to as Analytical Model of wood frame SHEar walls subjected to Vertical load (AMSHEV) is based on the kinematic behavior of wood frame shear walls and captures significant characteristics observed from experimental testing through appropriate modeling of three failure mechanisms that can occur within a shear wall under static monotonic load: 1) failure of sheathing-to-framing connectors, 2) failure of vertical studs, and 3) uplift of end studs from bottom sill. Previous models have not accounted for these failure mechanisms as well as the inclusion of vertical load, which has shown to reveal beneficial effects such as increasing the ultimate load capacity and limiting uplift of the wall as noted in experimental tests. Results from the proposed numerical model capture these effects within 7% error of experimental test data even when different magnitudes of vertical load are applied to predict the ultimate load capacity of wood frame shear walls.

Page generated in 0.0795 seconds