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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

REALISM : Reusable Elements for Animation using Local Integrated Simulation Models

Palmer, Ian J. January 1994 (has links)
No description available.
2

A local grid refinement technique for fluid flow predictions in 3-D

Pikoulas, Christos January 1995 (has links)
No description available.
3

Why has Slovenia been quicker to consolidate democracy than Croatia? : A comparative study since their indepedence in 1991

Strkalj, Kristijan January 2016 (has links)
This research will compare why two such comparable countries like Slovenia and Croatia have taken different paths towards consolidating democracy. The two countries on the same day in 1991 declared independence from Yugoslavia but only Slovenia managed to successfully consolidate democracy during the 1990s. The purpose of this study is to analyze what differences and similarities Croatia and Slovenia have had which has made them take different paths towards consolidating democracy. The theoretical framework will apply Linz and Stepans theory on consolidating democracy from the countries independence in 1991 until Croatia in 2013, like Slovenia in 2004, became member of the European Union. The results demonstrate that Croatia during the 1990’s were governed by a party and president in a non-democratic way while Slovenia since its independence has implemented all the necessary tools for a successful consolidation of democracy. In 1999 Croatia’s president died and this was the start of a new era in Croatian politics. In 2000 the ruling party was defeated by a coalition which immediately begun to integrate Croatia with the European Union and in essence started to consolidate democracy.
4

Symmetries and conservation laws in Lagrangian gauge theories with applications to the mechanics of black holes and to gravity in three dimensions. Symétries et lois de conservation en théorie de jauge Lagrangiennes avec applications à la mécanique des trous noirs et à la gravité à trois dimensions

Compère, Geoffrey 12 June 2007 (has links)
In a preamble, a quick summary of the line of thought from Noether's theorems to modern views on conserved charges in gauge theories is attempted. Most of the background material needed for the thesis is set out through a small survey of the literature. Emphasis is put on the concepts more than on the formalism, which is relegated to the appendices. The treatment of exact conservation laws in Lagrangian gauge theories constitutes the main axis of the first part of the thesis. The formalism is developed as a self-consistent theory but is inspired by earlier works, mainly by cohomological results, covariant phase space methods and by the Hamiltonian formalism. The thermodynamical properties of black holes, especially the first law, are studied in a general geometrical setting and are worked out for several black objects: black holes, strings and rings. Also, the geometrical and thermodynamical properties of a new family of black holes with closed timelike curves in three dimensions are described. The second part of the thesis is the natural generalization of the first part to asymptotic analyses. We start with a general construction of covariant phase spaces admitting asymptotically conserved charges. The representation of the asymptotic symmetry algebra by a covariant Poisson bracket among the conserved charges is then defined and is shown to admit generically central extensions. The asymptotic structures of three three-dimensional spacetimes are then studied in detail and the consequences for quantum gravity in three dimensions are discussed.
5

The Synergic Effects of Flow and Sphingosine 1-Phosphate on Sprouting Angiogenesis Into Three-Dimensional Collagen Matrices

Kang, Ho Jin 2011 May 1900 (has links)
The vascular endothelium continually senses and responds to both biochemical and mechanical stimuli to regulate vascular function in health and disease. The purpose of this dissertation was to understand the molecular mechanisms by which endothelial cells (ECs) respond to sphingosine 1-phosphate (S1P) and fluid wall shear stress (WSS) to initiate angiogenesis. To accomplish this, a novel cell culture system was developed to study the combined effects of S1P and WSS on inducing EC invasion into three-dimensional (3-D) collagen matrices. EC invasion required the presence of S1P, with the effects of S1P being enhanced by WSS to an extent comparable with S1P combined with pro-angiogenic growth factor stimulation. The extent of EC invasion depended on the magnitude of WSS in a biphasic manner, with the greatest induction occurring at 5.3 dyn/cm2 WSS. Several proteins have been implicated in EC invasion, including calpain, Akt, vimentin, p21-activated kinase (PAK), and membrane type 1-matrix metalloproteinase (MT1-MMP). Interestingly, activations of calpain and MT1-MMP and phosphorylations of Akt, PAK, and vimentin coincided with, and were required for, S1P- and WSS- induced EC invasion. Further, inhibitors of calpain, MT1-MMP, Akt and PAK all attenuated invasion induced by WSS and S1P. Calpain inhibition reduced Akt phosphorylation, vimentin cleavage, and MT1-MMP membrane translocation, suggesting that calpain regulates MT1-MMP via Akt phosphorylation and vimentin remodeling. Akt inhibition also completely blocked MT1-MMP membrane translocation and decreased phosphorylation of PAK and vimentin. In summary, these results suggest a new molecular pathway by which the combination of S1P and WSS stimulates EC invasion through calpain, Akt, PAK and vimentin to regulate activation and membrane translocation of MT1-MMP in 3-D collagen matrices.
6

Aspects of non-AdS holographic dualities in three dimensions

Zwikel, Celine 15 June 2018 (has links) (PDF)
Cette thèse se concentre sur des aspects de dualités holographiques reliant une théorie gravitationnelle en trois dimensions à une théorie des champs sur le bord de cette espace, c'est-à-dire en dimensions deux. Dans le premier chapitre, nous passons en revue diverses méthodes, utilisées tout au long de la thèse, pour calculer des quantités conservées en théorie de jauge et plus particulièrement en gravitation. Ensuite, dans le deuxième chapitre, nous rappelons le cas d'école des espaces-temps localement anti-de Sitter (AdS) à trois dimensions et de leur théorie duale, les théories des champs conformes en deux dimensions. Les chapitres trois et quatre sont dédiés à la présentation d'espaces-temps non-AdS considérés dans cette thèse et de la dualité dans laquelle ils sont impliqués. Le premier s'intéresse aux espace-temps warped AdS, qui peuvent être vus comme une déformation d'AdS. Leur théorie des champs duale serait une théorie des champs conforme warped. Le second se concentre sur des solutions cosmologiques, localement plates, qui seraient duales à des théories des champs invariantes sous le groupe BMS$_3$ (groupe de symétrie des espaces asymptotiquement plats). Dans le chapitre cinq, nous révisons des notions de thermodynamique que nous utiliserons pour discuter des transitions de phase entre deux géométries appartenant au même espace des phases. Par exemple, entre l'espaces-temps AdS thermique et le trou noir localement AdS. La partie originale de la thèse traite d'abord des solutions maximalement symétriques dans n'importe quelle théorie invariante sous difféomorphisme. Nous prouvons que le calcul d'entropie gravitationnel est reproduit par le comptage asymptotique d'états dans la théorie duale. Ce travail est étendu au cas des espaces-temps warped. Nous montrons également que leur entropie du bulk et du bord sont en correspondance et ce pour toutes théories de gravitation. Ceci constitue une vérification non triviale des correspondances holographiques. Nous étudions aussi leurs transitions de phase. Finalement, nous posons les premières pierres d'une nouvelle correspondance holographique, impliquant une corde noire, en trouvant un ensemble de conditions au bord cohérent. Nous discutons également la thermodynamique des cordes noires. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
7

Three dimensional finite element analysis of the flow of polymer melts

Tenchev, R., Gough, Timothy D., Harlen, O.G., Jimack, P.K., Klein, D.H., Walkley, M.A. January 2011 (has links)
No / The finite element simulation of a selection of two- and three-dimensional flow problems is presented, based upon the use of four different constitutive models for polymer melts (Oldroyd-B, Rolie-Poly, Pom-Pom and XPP). The mathematical and computational models are first introduced, before their application to a range of visco-elastic flows is described. Results demonstrate that the finite element models used here are able to re-produce predictions made by other published numerical simulations and, significantly, by carefully conducted physical experiments using a commercial-grade polystyrene melt in a three-dimensional contraction geometry. The paper also presents a systematic comparison and evaluation of the differences between two- and three-dimensional simulations of two different flow regimes: flow of an Oldroyd-B fluid around a cylinder and flow of a Rolie-Poly fluid into the contraction geometry. This comparison allows new observations to be made concerning the relatively poor quality of two-dimensional simulations for flows in even quite deep channels.
8

Exact solutions of massive gravity in three dimensions

Chakhad, Mohamed 15 October 2009 (has links)
In recent years, there has been an upsurge in interest in three-dimensional theories of gravity. In particular, two theories of massive gravity in three dimensions hold strong promise in the search for fully consistent theories of quantum gravity, an understanding of which will shed light on the problems of quantum gravity in four dimensions. One of these theories is the “old” third-order theory of topologically massive gravity (TMG) and the other one is a “new” fourth-order theory of massive gravity (NMG). Despite this increase in research activity, the problem of finding and classifying solutions of TMG and NMG remains a wide open area of research. In this thesis, we provide explicit new solutions of massive gravity in three dimensions and suggest future directions of research. These solutions belong to the Kundt class of spacetimes. A systematic analysis of the Kundt solutions with constant scalar polynomial curvature invariants provides a glimpse of the structure of the spaces of solutions of the two theories of massive gravity. We also find explicit solutions of topologically massive gravity whose scalar polynomial curvature invariants are not all constant, and these are the first such solutions. A number of properties of Kundt solutions of TMG and NMG, such as an identification of solutions which lie at the intersection of the full nonlinear and linearized theories, are also derived. / text
9

Lean knowledge life cycle framework to support lean product development

Maksimovic, Maksim January 2013 (has links)
This research thesis presents the development of a novel Lean Knowledge Life Cycle (LeanKLC) framework to support the transformation into a Lean Product Development (LeanPD) knowledge environment. The LeanKLC framework introduces a baseline model to understand the three dimensions of knowledge management in product development as well as its contextualisation with acclaimed LeanPD process models. The LeanKLC framework comprises 23 tasks, each accomplished in one of the seven key stages, these being: knowledge identification, previous knowledge capture, knowledge representation, knowledge sharing, knowledge integration, knowledge use and provision and dynamic knowledge capture. The rigorous research methodology employed to develop the LeanKLC framework entailed extensive data collection starting with a literature review to highlight the gap in the current body of knowledge. Additionally, industrial field research provides empirical evidence on the current industrial perspectives and challenges in managing product development knowledge. This research was part of a European FP7 project entitled Lean Product and Process Development (LeanPPD), which provided the opportunity to involve industrial collaborators in action research to support practical aspects during the LeanKLC framework development. The synthesis with the current LeanPD paradigm is accomplished by demonstrating the LeanKLC stages in two distinct streams related to the development of A3 thinking for problem solving and the development of trade-off curves to facilitate set based design at the conceptual stage. The novel LeanKLC is validated in two case studies providing the industry with detailed insights on real product development applications. In particular this research highlights that the LeanPD knowledge environment is a wide subject area that has not yet been thoroughly understood and that industry engagement in empirical research is vital in order to realise any form of LeanPD transformation.
10

Multi-view and three-dimensional (3D) images in wear debris analysis (WDA)

Mat Dan, Reduan January 2013 (has links)
Wear debris found in gear lubricating oil provides extremely valuable information on the nature and severity of gear faults as well as remaining gear life. The conventional off-line process of taking samples of oil for testing of wear debris is a hindrance because it is laborious, expensive, delays information collection, and is expert oriented. In view of these limitations, the development of automating wear debris particle analysis using various approaches has been ongoing for years. However, existing online technology does not encourage widespread use of wear debris analysis (WDA) in the industry. High costs coupled with expert and labour requirements have led users to use other types of condition-based maintenance, such as vibration. There is a need to develop a WDA technique that is relatively cheap, online, requires little expertise to handle, and provides more information for maintenance decision-making. This PhD thesis proposes a WDA technique which uses image processing and three-dimensional image reconstruction to diagnose the health of machinery. Its emphasis is on using the thickness and volume of the particles generated over time to predict the onset of gearbox failure, so that maintenance action can be taken before gears reach catastrophic failure.

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