A demanda por aumento da eficiência energética vem obrigando empresas e centros de pesquisa a desenvolver e utilizar novos materiais buscando a redução de peso. Entre esses materiais, destacam-se as ligas de magnésio, com aproximadamente dois terços da densidade do alumínio e a melhor relação peso/resistência entre os metais. Porém, a utilização do magnésio em altas temperaturas tem suas limitações, devido à baixa resistência a fluência e a formação do precipitado -Mg17Al12 que tem baixo ponto de fusão, tornando as ligas de magnésio mais suscetíveis aos efeitos de deslizamento nos contornos de grãos. Algumas ligas de magnésio contendo elementos terras raras foram desenvolvidas para melhorar a resistência a fluência. O trabalho em questão visa analisar o comportamento da liga Mg6Al3La1Ca, correlacionando os parâmetros de solidificação com as propriedades mecânicas: dureza, alongamento específico, limite de escoamento e limite de resistência à tração. Para isso, foram solidificados unidirecionalmente, com atmosfera de argônio, três lingotes da liga Mg6Al3La1Ca a partir de sobreaquecimento de 780°C, 715°C e 650°C. O resfriamento dos lingotes ocorreu no forno e por resfriamento forçado. Os resultados obtidos de limite de resistência à tração, limite de escoamento e dureza tem uma relação direta com a temperatura de vazamento onde os melhores resultados foram obtidos com as temperaturas mais elevadas. Portanto, conclui-se que na temperatura de 780°C com resfriamento forçado foram obtidas as melhores propriedades mecânicas. / The demand for increased energy efficiency is forcing companies and research centers to develop and use new materials aimed at reducing weight. Among these materials, there is magnesium alloys, because it has about two-thirds of the density of aluminum and the best weight/resistance between the metals. However, the use of magnesium at elevated temperatures has its limitations due to low resistance to creep; the formation of -Mg17Al12 precipitate which has a low melting point makes the magnesium alloy more susceptible to slip around the grains. Some magnesium alloys containing rare earth elements have been developed to improve resistance to creep. The work in question is to analyze the behavior the Mg6Al3La1Ca alloy, correlating the parameters of solidification with the mechanical properties: hardness, specific elongation, limits yield strength and tensile strength. For that, three ingots of the alloy Mg6Al3La1Ca were solidified unidirectionally using argon atmosphere with overheating of 780°C, 715°C and 650°C. The cooling of ingots occurred in the furnace and by forced cooling. The results of limit tensile strength, yield strength and hardness have a direct relation with the pouring temperature where the best results were obtained with higher temperatures. Therefore, it is concluded that the best mechanical properties were obtained at temperature of 780°C with forced cooling.

Les robots ont amélioré les industries, en particulier les systèmes d'assemblage basé sur des conveyors et ils ont le potentiel pour apporter plus de bénéfices: transports; exploration de zones dangereuses, mer profonde et même d'autres planètes; santé et dans la vie courante.Une barrière majeure pour leur évasion des environnements industriels avec des enceintes vers des environnements partagés avec les humains, c'est leur capacité réduite dans les tâches d’interaction physique, inclue la manipulation d'objets.Tandis que la dextérité de la manipulation n'est pas affectée par la cécité dans les humains, elle décroit énormément pour les robots: ils sont limités à des environnements statiques, mais le monde réel est très changeant. Dans cette thèse, nous proposons une approche différente qui considère le contrôle du contact pendant les interaction physiques entre un robot et l'environnement.Néanmoins, les approches actuelles pour l'interaction physique sont pauvres par rapport au numéro de tâches qu'elles peuvent exécuter. Pour permettre aux robots d'exécuter plus de tâches, nous dérivons des caractéristiques tactiles représentant les déformations de la surface molle d'un capteur tactile et nous incorporons ces caractéristiques dans le contrôleur d'un robot à travers des matrices de mapping tactile basées sur les informations tactiles et sur les tâches à développer.Dans notre première contribution, nous montrons comment les algorithmes de traitement d'images peuvent être utilisés pour découvrir la structure tridimensionnelle subjacente du repère de contact entre un objet et une matrice de capteurs de pression avec une surface molle attachée à l’effecteur d'un bras robotique qui interagit avec cet objet. Ces algorithmes obtiennent comme sorties les soi-disant caractéristiques tactiles. Dans notre deuxième contribution, nous avons conçu un contrôleur qui combine ces caractéristiques tactiles avec un contrôleur position-couple du bras robotique.Il permet à l'effecteur du bras déplacer le repère du contact d'une manière désirée à travers la régulation d'une erreur dans ces caractéristiques. Finalement, dans notre dernière contribution,avec l'addition d'une couche de description des tâches, nous avons étendu ce contrôleur pour adresser quatre problèmes communs dans la robotique: exploration, manipulation, reconnaissance et co-manipulation d'objets.Tout au long de cette thèse, nous avons mis l'accent sur le développement d'algorithmes qui marchent pas simplement avec des robots simulés mais aussi avec de robots réels. De cette manière, toutes ces contributions ont été évaluées avec des expériences faites avec au moins un robot réel. En général, ce travail a comme objectif de fournir à la communauté robotique un cadre unifié qui permet aux bras robotique d'être plus dextres et autonomes. Des travaux préliminaires ont été proposés pour étendre ce cadre au développement de tâches qui impliquent un contrôle multi-contact avec des mains robotiques multi-doigts. / Robots have improved industry processes, most recognizably in conveyor-belt assemblysystems, and have the potential to bring even more benefits to our society in transportation,exploration of dangerous zones, deep sea or even other planets, health care and inour everyday life. A major barrier to their escape from fenced industrial areas to environmentsco-shared with humans is their poor skills in physical interaction tasks, includingmanipulation of objects. While the dexterity in manipulation is not affected by the blindnessin humans, it dramatically decreases in robots. With no visual perception, robotoperations are limited to static environments, whereas the real world is a highly variantenvironment.In this thesis, we propose a different approach that considers controlling contact betweena robot and the environment during physical interactions. However, current physicalinteraction control approaches are poor in terms of the range of tasks that can beperformed. To allow robots to perform more tasks, we derive tactile features representingdeformations of the mechanically compliant sensing surface of a tactile sensor andincorporate these features to a robot controller via touch-dependent and task-dependenttactile feature mapping matrices.As a first contribution, we show how image processing algorithms can be used todiscover the underlying three dimensional structure of a contact frame between an objectand an array of pressure sensing elements with a mechanically compliant surfaceattached onto a robot arm’s end-effector interacting with this object. These algorithmsobtain as outputs the so-called tactile features. As a second contribution, we design a tactileservoing controller that combines these tactile features with a position/torque controllerof the robot arm. It allows the end-effector of the arm to steer the contact frame ina desired manner by regulating errors in these features. Finally, as a last contribution, weextend this controller by adding a task description layer to address four common issuesin robotics: exploration, manipulation, recognition, and co-manipulation of objects.Throughout this thesis, we make emphasis on developing algorithms that work notonly with simulated robots but also with real ones. Thus, all these contributions havebeen evaluated in experiments conducted with at least one real robot. In general, thiswork aims to provide the robotics community with a unified framework to that will allowrobot arms to be more dexterous and autonomous. Preliminary works are proposedfor extending this framework to perform tasks that involve multicontact control withmultifingered robot hands.

Le désarmement est l’un des axes stratégiques primordiaux de la politique internationale. Il se pose, de manière récurrente, la sempiternelle question de son rapport à la paix, à la sécurité internationale et au développement. Car, le désarmement est, indubitablement, un maillon essentiel de la chaîne indispensable pour bâtir un monde débarrassé de menaces et de risques consécutifs à une militarisation à outrance. Son sucés ou son échec est lié à la configuration du monde. C’est une question de volonté politique dont les États sont les acteurs majeurs. La mutation du contexte international relance la problématique du désarmement. Car, le désarmement vise à éliminer les armes dont l’accumulation constitue une source de tension internationale. Il concerne la réduction du format des armées, la contraction des dépenses militaires et le contrôle du transfert de la technologie militaire. Il permet de libérer à des fins pacifiques des ressources nécessaires à d’autres secteurs de l’économie. L’histoire du désarmement révèle des pratiques, parfois, unilatérales et coercitives. La mise en œuvre du désarmement n’est possible que lorsque, se manifeste une volonté dédiée à sa concrétisation. Il existe un lien entre les dépenses consacrées aux armements et le développement économique et social. Cependant, la diminution de l’influence incommensurable des complexes militaro-industriels, la reconversion des industries de défense conditionnent aussi le désarmement. La coopération multilatérale et la mutualisation des moyens restent des possibilités de garanties pour un désarmement efficient et efficace. / Disarm is one of the main strategics axis of the international politics. It happened, in a recurring way, the sempiternal question of his report to peace, international security and the development. Because disarming, is undoubtedly, an essential link of the chains to build a world without threats and consecutive risks with excess of militarization. Its success or its failure is linked to the configuration of the world. It is a question of political good-will which states are the major actors. The change of the international context boost the problems of disarming. Because, disarming aims to eliminate the weapons which accumulation constitutes a source of international tensions. It relates to the reduction of the format of armed, the contraction of the soldiers expenditure and the control of the military technology transfer. It permits to release peaceful purposes necessary resources to other sectors of the economy. The history of disarming raises the practices, sometimes, links and coercive. The implementation of disarming is not possible when, appears a dedicated will in its concretization. There is a bond between the expenditure devoted to the arms, the economic and social development. However, the reduction in the incommensurable influence of the military-industrial complexes, the reconversion of industries of expenditure condition also disarming. The multilateral co-operation and the mutualism of the means remain the possibilities of the guarantees for an efficient and effective disarming.

Ce travail étudie les changements dans les politiques d’exportation d’armement de la France et de la Suède depuis la fin de la guerre froide. Il cherche à expliquer pourquoi on assiste d’abord à un phénomène de convergence entre les deux Etats (1990-2005) puis à un phénomène de divergence (2005-2015). La thèse montre que les explications du changement ne viennent pas uniquement de facteurs internationaux (transformations économiques, diplomatiques) ou internes (évolutions de l’industrie de défense, scandales, alternances politiques), mais des rapports de force entre coalitions « pro-soutien » et « pro-contrôle » des ventes d’armes. L’intervention et l’enchaînement de mécanismes causaux faisant appel au travail politique d’acteurs du sous-système de politique publique sont nécessaires pour relier les facteurs de changement internationaux et domestiques aux réformes observées dans les politiques d’exportation d’armements. / This thesis studies the changes in French and Swedish arms export policies since the end of the Cold War. It seeks to explain why we first observe a converging trend between the two states (1990-2005) and then a diverging trend (2005-2015). The thesis shows that the explanations for policy change do not stem only from international (economic and diplomatic transformations) or domestic factors (defence industry evolutions, arms trade scandals, government political shifts), but from the power struggles between “pro-support” and “pro-control” arms export coalitions. The intervention and succession of causal mechanism requiring actors’ political work is necessary to link the international and domestic factors of change to the observed reforms in arms export policies.

Magister Legum - LLM / South Africa

Magister Legum - LLM

AFRIKAANS: In hierdie proefskrif word wapenbeheer en ontwapening 5005 dit na die Koue Oorlog op globale-, streek-(spesifiek Afrika) en nasionale (spesifiek Suid-Afrika) vlakke toegepas is ondersoek en ontleed. Die doel van die studie is om bestaande kennis op 'n oorsigtelike gekonsolideerde wyse, veral ten opsigte van Afrika en Suid-Afrika uit te brei omdat 'n behoefte in die opsig met die indiening van die navorsingsvoorstel geïdentifiseer is; om aan te toon dat wapenbeheer en ontwapening selfs na die beëindiging van die Koue oorlog steeds wëreldwyd van kardinale belang is; en dat daar na die Koue Oortog ongekende sukses op globale vlak, in Afrika tot 'n mindere mate, en in Suid-Afrika groot sukses met wapenbeheer en ontwapening behaal is. 'n Radikale verandering in binnelandse en buitelandse beleid deur Suid-Afrika het tot gevolg gehad dat Suid-Afrika in die vroeë negentigerjare die eerste staat in die wêreld geword het wat kemontwapening algeheel toegepas het. Suid-Afrika se chemiese en biologiese oorlogvoe¬ringprogramme is ook in die vroeë negentigerjare beëindig. Die demokratisering van die politieke bestel in Suid-Afrika in 1994 het ook grootskaalse betrokkenheid van die Suid¬-Afrikaanse regering by wapenbeheer en ontwapening op globale-, streek- en nasionale vlakke tot gevolg gehad. Die doel van die studie is ook om aan te toon tot watter mate die bëeindiging van die Koue Oortog 'n invloed op wapenbeheer en ontwapening gehad het. Die beëindiging van die Koue Oorlog was 'n resultaat van 'n radikale verandering in binnelandse en buitelandse beleid deur die voormalige Sowjet-Unie. Die studie aangaande wapenbeheer en ontwapening na die Koue Oorlog word voorafgegaan deur 'n ontleding van die teoretiese konsepte van wapenbeheer en ontwapening en die ontwikkeling van die konsepte deur teoretici van die twintigste eeu. Die benaderings met wapenbeheer en ontwapening soos deur hierdie teoretici ontwikkel, word dan ook in die studie toegepas op die verdrae en ooreenkomste wat na die Koue Oorlog onderteken en/of geratifiseer is. Die metode van ondersoek wat vir die bestudering van die onderwerp gevolg is, is histories-beskrywend en analities van aard. Die doeI hiermee was om die verskillende wapenkategorieë en tydperke af te baken en dan vas te stel tot hoe 'n mate wapenbeheer en ontwapening globaal, en meer spesifiek op streek-(Afrika) en nasionale (Suid-Afrika) vlakke na die Koue Oorlog toegepas is. Wapenbeheer en ontwapening soos voor en na die Koue Oorlog toegepas, word ooreenkomstig die teorie, soos in hoofstuk 1 uiteengesit, beoordeel. Die prosedure wat met die navorsing gevolg is, is soos volg: selektering van boeke, dokumente, tydskrifte, nuusblaaie en publikasies van verskillende aard; dataversameling en bestudering van tekse; data-ontleding ten einde vas te stel watter toepaslik is; die proses van vertolking en interpretering van die inligting; toepassing van inligting; evaluasie; en die vorming van gevolgtrekkings. ENGLISH: In this dissertation the processes of arms control and disarmament as implemented at global, regional (Africa) and national (South Africa) levels are investigated and analysed. The purpose of the study is to widen existing knowledge in a consolidated manner, especially with regard to Africa and South Africa. A need in this regard was identified with the submission of the proposal for the study. A further purpose of the study is to indicate that arms control and disarmament, even after the end of the Cold War, is still of utmost importance; and that success of formerly unknown proportions was obtained with arms control and disarmament after the Cold War on the global level, to a lesser extent in Africa, and with great success in South Africa. A radical change in internal as well as foreign policy by the South African government resulted in South Africa being the first state in the world to implement total nuclear disarmament in the early nineties. South Africa's chemical and biological warfare programs were also terminated in the early nineties. The democratisation of the political environment in South Africa in 1994 resulted in South Africa becoming involved in arms control and disarmament at global, regional and national levels. The purpose of the study is also to illustrate to what extent the ending of the Cold War had an influence on arms control and disarmament. The end of the Cold War was a result of a radical change in internal as well as foreign policies of the former Soviet Union. The study of arms control and disarmament after the Cold War is preceded by an analysis of the theoretical concepts of arms control and disarmament by twentieth century theorists. The approaches to arms control and disarmament, as developed by these theorists, are then applied to treaties and agreements, which were signed/ ratified before and after the Cold War. The method of investigation that was followed for the study was historically descriptive and analytical of nature. The purpose was to differentiate between the different categories of weapons and the different periods during which arms control and disarmament were implemented since the earliest times and during and after the Cold War. The approaches to arms control and disarmament, during and after the Cold War, are also assessed according to the theory as explained in chapter 1. The procedure which was followed whilst doing research for the study was as follows: The selection of books, documents, magazines, newspapers, and publications of various nature; compilation and studying of data; analysis of data to establish which would be appropriate to use; the process of interpretation of the information; application; evaluation and forming of conclusions. <p / Thesis (DPhil (International Politics))--University of Pretoria, 2006. / Political Sciences / unrestricted

No description available.

This study analyzes current trends in metrology in the field of portable coordinate measuring machines and describes current methods for measurement system and process evaluation. Obtained knowledge is applied, in order to evaluate the capability of measurement system, which consists of articulated measurement arm and measurement standard.

The humanitarian crisis in Yemen is a man-made famine. The concept of famine crimes has been introduced to problematise and criminalise conduct that leads to the creation of famine. According to an analytical framework proposed by Marcus (2003) there are four categories of famine crimes, which constitute four degrees of conduct through which famines are created, sustained or not prevented. A pivotal role in the creation of the famine in Yemen is played by Saudi Arabia, that relies on the import of military equipment to conduct a military intervention in Yemen. Through Common Position 2008/944/CFSP, the European Member States committed themselves to eight criteria against which arms licence applications are tested. This aims to prevent arms deliveries to questionable receivers, yet various EU Member States export military equipment to Saudi Arabia. In this thesis, the famine crimes framework is applied to foreign actors in a case study of the EU arms trade to Saudi Arabia between 2015 and 2019. The research project answers the question: what insights about the European Union’s role in the creation of famine in Yemen can be gained from the application of the famine crimes framework to the European Union’s arms trade to Saudi Arabia? Since Saudi Arabia violated international humanitarian law in Yemen and used EU-produced arms to do so, the Common Position requires EU Member States to pursue restraint in arms export to Saudi Arabia. Accordingly, the number of licences that were approved by European Member States, as well as their value, declined after 2015. However, there were notable fluctuations and the Member States adopted differing approaches. As such, the EU as a collective body appeared unable to prevent arms exports to Saudi Arabia. In the application of the famine crimes framework, it becomes clear that this inability can be interpreted as a famine crime.Altogether, this exploratory study provides insights into the role of foreign actors in the creation of famine by applying the famine crimes framework. Further research on the extent to which the EU as a collective body could enhance compliance with the Common Position and prevent exports to questionable receivers could be performed to better categorise its conduct within the framework. Further research could also explore the role of other foreign actors and apply the famine crimes framework to other case studies.