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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.
501

Geologic Typography

Karnes, Eric 11 May 2010 (has links)
In this project, I explore how the processes and structures of non-design disciplines can influence typographic form. Using the field of geology as a test case, I apply geologic processes to typographic form in order to create dimensional structures that speak to a wide audience.
502

Three dimensional perfused cell culture for in vitro toxicity testing

Yang, Jie January 2011 (has links)
This study describes the development of a novel method of three dimensional perfused cell culture for in vitro toxicity testing. Multiple parallel perfused microbioreactors (TissueFlex<sup>TM</sup>) were adopted to provide a well-controlled cell culture environment. Alginate and collagen type I, commonly used as hydrogel scaffolds to support cell culture, were tested as the scaffolding materials for this application. Alginate supports cell proliferation, but does not support cell attachment. Collagen gel (type I), good for cell attachment but with poor mechanical strength, could be used at the high concentration of 5mg/ml to prevent the degradation of the gel. Improvement of collagen biomechanical property by a purpose-designed compressor to physically induce cross-linking showed promising results and merits further study. The suitability of alamarBlue&reg; assay, a common non-toxic non-destructive viability assay method, was confirmed for this study and the protocol was optimised. To demonstrate the effectiveness of three dimensional perfused cell culture, human mesenchymal stem cells (MSC) seeded in collagen type I were employed to test the cell inhibition of two antibiotics, trimethoprim and pyrimethamine. The results displayed the perfusion system has greater advantage and sensitivity than the static system, as does these of 3D scaffolds, compared with 2D. Such differences are related to the continuous supply of fresh culture medium to keep cells at a stable pH, temperature, oxygen, and a more physiological like environment. The cytotoxicity of two stereoisomer compounds, obtained confidentially from Pfizer. Ltd., was assessed using the developed method and compared to conventional 2D static and perfused culture by using rat adipose mesenchymal stem cells. The results successfully distinguished toxic and non-toxic compounds and also demonstrated that the 3D perfused system improved the prediction of drug toxicity over 2D culture. 3D perfused bioreactors were applied to hepatotoxicity study using freshly isolated rat hepatocytes. Only algimatrix<sup>TM</sup> supported hepatocyte spheroid formation among those tested including collagen type I, alginate beads, poly lactic acid fibres, and Algimatrix<sup>TM</sup>. A new variation of TissueFlex<sup>TM</sup> bioreactor with micro-patterned surface, designed specifically for hepatocyte self-assembly culture without use of any scaffold, was tested. The results demonstrated that, compared with the standard sandwich culture, the self-assembly culture in the micro-patterned bioreactors showed high cell viability, biomarkers expression, as well as more physiological immunocytochemistry. Moreover, the differential gene expression indicated that self-assembly culture could provide more relevant information regarding metabolising processes than the 2D sandwich culture, which would potentially improve hepatotoxicity prediction. In conclusion, 3D perfused cell culture for in vitro toxicity testing improved the predictivity, reliability and physiological relevance of drug toxicity compared to traditional 2D culture.
503

Tolérancement flexible d'assemblages de grandes structures aéronautiques / Flexible tolerancing of large aeronautical structures assemblies

Stricher, Alain 08 February 2013 (has links)
Comme son nom l'indique, le tolérancement flexible a pour objectif de tenir compte de la souplesse des pièces dans un processus de tolérancement. Il permet d'évaluer les défauts géométriques admissibles par des critères aussi bien géométriques que mécaniques. Ces travaux abordent en premier lieu l'élaboration de modèles adéquats permettant de prédire le comportement mécanique d'un assemblage de grandes pièces relativement souples lorsqu'elles sont sujettes à des défauts géométriques issues du procédé de fabrication. Une méthode a alors été proposée pour y implémenter des variations géométriques aléatoires réalistes vis-à-vis de ces hypothétiques défauts géométriques. Pour simuler les opérations d'assemblage, le phénomène de contact unilatéral et les variations de rigidité dues aux variabilités géométriques ont été prises en compte. En fonction de ces hypothèses, les stratégies d'analyse de tolérance avec Monte Carlo ou la méthode des coefficients d'influence ont été comparées afin de choisir celle minimisant les coûts de calcul tout en conservant la justesse des résultats. Finalement, ces travaux s'achèvent sur une étude de cas industriel : un treillis supportant des équipements sous le plancher du fuselage d'un Airbus A350. / As indicated by its name, the purpose of flexible tolerancing is to take into account the flexibility of the parts in a tolerancing process. It allows to evaluate the permissibles geometrical defects by both geometrical and mechanical criteria. These works deal first with the elaboration of a model able to predict the mechanical behaviour of an assembly of larges and flexibles parts which are suject to geometrical defects induced by their manufacturing process. A method has thus been suggested in order to implement geometrical variations which are realistic according to these hypothetical geometrical defects. To simulate the assembling process, the unilateral contact phenomenon and the stiffness variations induced by the geometrical variability have been taken into account. Depending on these assumptions, some strategies of tolerance analysis with Monte Carlo or the method of influence coefficients have been compared in order to choose the one minimizing the computational costs while maintaining the accuracy of the results. Finally, these works are completed with an industrial study case: a truss supporting equipments and hanging under the fuselage floor of an Airbus A350.
504

Ochrana prostorových ochranných známek a průmyslových vzorů / Protection of three dimensional trade marks and designs

Čech, Jakub January 2011 (has links)
Resumé Protection of Three-Dimensional Trade Marks and Designs The aim of this work was to examine the registration requirements of three- dimensional trade marks and designs, to compare the rights and protection conferred by each of these forms of intellectual property and to observe the interaction of trade mark and design when their subject matter is identical or similar. First part of this work focuses on the questions regarding the registration requirements of the three-dimensional trade marks. The work looks closely on what constitutes a sign and which absolute grounds for refusal of registration are mostly employed when dealing with the three-dimensional trade marks. Furthermore this work looks at exclusion of registration of certain types of shapes, on the requirement of good faith when applying for trade mark registration and briefly at the average consumer. The landmark cases cited in this part of the work are Dyson v Registrar of Trade Marks, Philips v Remington, Henkel v OHIM, Lego v OHIM and Lindt v Franz Hauswirth. Second part of this work looks at the definition of design and its relationship to product itself. It also looks at the background of design protection and closely at the registration requirements of designs, namely the novelty requirement, the individual character and exclusion of...
505

Three-dimensional knowledge representation using extended structure graph grammars

20 November 2014 (has links)
M.Sc. (Computer Science) / The purpose of this disssertation is to study methods to represent structures in three-dimensions. Due to the fact that chemical molecules are mostly complex three-dimensional structures, we used chemical molecules as our application domain. A literature study of current chemical information systems was undertaken. The whole spectrum of information systems was covered because almost all of these systems represent chemical molecules in one way or another. Various methods of three-dimensional structure representation were found in our literature study. All of these methods were discussed in the context of its own application domain. Structure graph grammars were examined and explained in detail. A small object-based system with structure graph grammars as the underlying principle was developed. We speculated on the use of such "intelligent" graph grammars in structure interpretation and identification. Further research in this area was also identified.
506

II-VI Core-Shell Nanowires: Synthesis, Characterizations and Photovoltaic Applications

Wang, Kai 02 August 2012 (has links)
The emergence of semiconducting nanowires as the new building blocks for photovoltaic (PV) devices has drawn considerable attention because of the great potential of achieving high efficiency and low cost. In special, nanowires with a coaxial structure, namely, core-shell structures have demonstrated significant advantages over other device configurations in terms of radial charge collection and cost reduction. In this dissertation, several core-shell nanowire structures, including ZnO/ZnSe, ZnO/ZnS, and CdSe/ZnTe, have been synthesized and the photovoltaic devices processed from a ZnO/ZnS core-shell nanowire array and a single CdSe/ZnTe core-shell nanowire have been demonstrated. By combining the chemical vapor deposition and pulsed laser deposition (PLD) techniques, type-II heterojunction ZnO/ZnSe and ZnO/ZnS core-shell nanowire array were synthesized on indium-tin-oxide substrates. Their structures and optical properties have been investigated in detail, which revealed that, despite highly mismatched interfaces between the core and shell, both systems exhibited an epitaxial growth relationship. The quenching in photoluminescence but enhancement in photocurrent with faster response upon coating the core with the shell provides the evidence that the charge separation and collection in the type II core-shell nanowire is greatly improved. This demonstration brings much greater flexibility in designing next generation PV devices in terms of material selection and device operation mechanisms for achieving their maximum energy conversion efficiencies at a low cost and in an environmentally friendly manner. In order to achieve a high quality interface in the core-shell nanowire, CdSe and ZnTe, which have close lattice parameters and thermal expansion coefficients, were chosen to fabricate nanowire solar cells. ZnTe and CdSe nanowires were first synthesized by thermal evaporation and the shells were subsequently deposited by PLD. ZnTe/CdSe nanowires represented an inhomogeneous coating while the CdSe/ZnTe core-shell exhibited a conformal coating with obvious ZnTe eptilayer. The final PV device based on an individual CdSe/ZnTe nanowire demonstrated an efficiency of ~1.7%. In addition, a controllable synthesis of CdSe nanowire array on muscovite mica substrate was presented, providing the possibility to harvest hybrid energies in an all-inorganic nanowire array.
507

Morphogenesis Control By Mechanical Stress / Mechanism behind efficient plant growth

Khadka, Jason 29 May 2019 (has links)
No description available.
508

A proposition for how musical competencies could benefit 3D character animators when synchronising performances to pre-recorded music using Khumba as a case study

Jacobs, Carelize Johani January 2017 (has links)
Research Report Master of Arts in Digital Animation (Coursework and Research Report) University of the Witwatersrand Faculty of Humanities The Wits School of Arts June 2017 / Even though a significant amount of research has been conducted over the years on film music and animation, these two fields of academic study mostly developed independently from each other. Little attention has been given to these two fields in terms of how they are deployed together, particularly after the ‘Golden Age’ of Hollywood filmmaking. This study, from an animation perspective, contributes to this need for research with an investigation and eventual proposition that will elucidate and advance the integration and contemporary deployment practices and processes of music and character animation. The aim of the study was to identify and suggest the ideal musical competency set a character animator would benefit from and, to propose an approach for notation in which these competencies are used to digitally animate characters moving to the beat of pre-recorded music for a 3D animation feature-length film. A qualitative research approach was followed and the research methodology consisted of a historical analysis, studying current practices and the analysis of a case study. The South African 3D computer-animated feature film, Khumba (2013), produced by Triggerfish Animation Studios, was used as the case study. Reasons for its suitability were twofold: Firstly because the researcher could easily access the animators (which was essential) and secondly, because the film had the musical scenes required to conduct the research. The focus was on the musical scenes in the film. The integration of animation and music in a scene was analysed, allowing the researcher to show how Khumba animators could have benefited from the suggested musical competencies and from using the proposed method when animating musical scenes. A universally agreed approach for notation in animating-to-music doesn’t exist. However, a method known as the bar sheet was used by earlier animators, requiring them to have a basic knowledge and understanding of music. This study proposes the reintroduction of an adapted version of the original bar sheet, digitised for assimilation with contemporary technology. A plug-in for Autodesk Maya was also proposed as an output of the research. Ultimately, this research has the potential to lead to a heightened proficiency of character animators when animating musical scenes in 3D feature-length films. In addition, the research could prompt a universally agreed approach for notation which combines traditional and new methods and techniques. The adoption of this approach could also lead to changes in the working practices of film making teams and the work flow within production pipelines. / MT2018
509

Strukturní studie interakcí proteinu LEDGF/p75. / Structural studies of LEDGF/p75 interactions

Těšina, Petr January 2016 (has links)
3 ABSTRACT LEDGF/p75 protein is a human transcriptional co-activator and epigenetic reader associated with transcriptionally active chromatin. It is crucial for HIV integration and MLL1 fusion-driven leukemia development. Interactions of LEDGF/p75 with HIV integrase (HIV IN) and MLL1-menin complex are considered an attractive therapeutic target for drug development. LEDGF/p75 interacts with both HIV IN and MLL1-menin complex through its integrase binding domain (IBD). While the pathophysiological interactions of LEDGF/p75 IBD were intensively studied, little was known about the physiological ones. In addition to HIV IN and MLL1, the LEDGF/p75 IBD also interacts with JPO2, PogZ, ASK and MLL2. In search for specific inhibitors of LEDGF/p75 IBD interaction with HIV IN and MLL1, it is essential to obtain detailed information about its interactions with all binding partners. The IBD-MLL1-menin complex has been structurally characterized, but only partially. Using NMR spectroscopy, we identified and mapped a novel part of the IBD-MLL1 interface. This additional interface is able to maintain the interaction between LEDGF/p75 and MLL1 even without the presence of menin, which was considered necessary. Moreover, colony forming assays of primary leukemic blasts revealed that this additional interface is essential for...
510

Optimisation du calcul des dispersions angulaires tridimensionnelles / Optimization of the three-dimensional angular dispersions calculation

Mezghani, Aïda 05 November 2010 (has links)
Ce travail de recherche traite un problème qui joue un rôle très important pour le succès desprogrammes de fabrication : le tolérancement tridimensionnel, essentiel pour définir la géométried'une pièce mécanique assurant sa meilleure fonctionnalité dans un assemblage avec uneprécision optimale.Une méthode des chaînes de cotes angulaires tridimensionnelles a été développée. Cette méthodepermet d’une part l’optimisation du calcul des dispersions angulaires tridimensionnelles etd’autre part de valider la gamme de fabrication par la vérification du respect des tolérancesimposées par le bureau d’études en tenant compte des précisions des procédés utilisés.Cette étude est basée sur l’analyse de deux fonctions paramétrées qui sont étudiées pourdéterminer le défaut fabriqué : le défaut angulaire et la longueur projetée. Le défaut angulairereprésente le cumul des défauts angulaires générés par le processus de fabrication de la pièce. Lesdéfauts angulaires sont déterminés en fonction de la précision des machines outils. La longueurprojetée de la surface tolérancée est une caractéristique qui dépend uniquement de la forme de lasurface.Ensuite, à partir de ces deux fonctions paramétrées, le défaut fabriqué est déterminé puiscomparé avec la condition fonctionnelle afin de vérifier si la gamme choisie permet en fin duprocessus de fabrication de donner une pièce conforme. / To verify the capacity of a manufacturing process to make the corresponding parts it is necessaryto simulate the defects that it generates and to analyze the correspondence of produced parts withthe functional tolerances. In order to check the capability of a manufacturing process to carry outsuitable parts, it is necessary to analyze each functional tolerance.The main objective of our work is to define a methodology of tolerancing analysis. Thedeveloped method allows to determine the manufacturing tolerances in the case of angular chainsof dimensions and to check its correspondence with the functional tolerances.The objective of this work is to analyze two parameterized functions: the angular defect and theprojected length of the toleranced surface. The angular defect represents the angular defectgenerated by the manufacturing process. It is determined according to the machine toolsprecision. We consider only the geometrical defects, making the assumption that the form defectsare negligible. The projected length of toleranced surface is a characteristic which depends onlyon the form of surface.The manufactured defect is determined from these two parameterized functions. Then it will becompared with the functional condition in order to check if the selected machining range allows,at end of the manufacturing process, to give a suitable part.

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