Auswahl der wissenschaftlichen Literatur zum Thema „Externé osi“

De nombreuses tentatives de reconstruction de l’étendue du paléo-pergélisol à partir de données de terrain montrent que de grandes parties de la France ont été affectées à la fin du Pléistocène. Cette étendue maximale a été attribuée au Dernier Maximum Glaciaire (DMG). Néanmoins, des contradictions existent entre les différentes reconstructions qui ont été réalisées pendant près d’un siècle ; elles résident en partie dans l’absence de consensus sur la signification paléoclimatique de certaines structures périglaciaires. De plus, le cadre chronologique utilisé pour ces reconstructions est principalement basé sur des datations relatives et/ou sur l’hypothèse que le maximum de froid durant le dernier glaciaire a été atteint pendant le DMG. Dans ce contexte, il était nécessaire de réévaluer les structures déjà décrites à la lumière de notre connaissance actuelle des processus périglaciaires et d’en chercher de nouvelles pour datation. L’approche développée pour résoudre ces problèmes a été divisée en trois parties. Tout d’abord, une base de données homogène fournissant un accès simple aux structures périglaciaires répertoriées sur le territoire français a été constituée. Celle-ci permet de remettre un site ou une structure dans un contexte régional pour éviter les interprétations simplistes et favorise une vision à l’échelle nationale. Cette base de données est accessible en ligne (https://afeqeng.hypotheses.org/48). Les données en coupe concernant les coins sableux, les pseudomorphoses de coin de glace et les coins composites ainsi que les données obtenues à partir de photos aériennes sur les polygones et les sols striés ont été compilées. Dans la deuxième partie de notre travail, nous nous sommes attachés à traiter les données recueillies. L’analyse à l’aide d’un SIG nous a apportée des informations sur l’influence de différents facteurs sur le développement des structures périglaciaires. Des comparaisons avec un ensemble de données du Nord de l’Europe a rendu possible la proposition d’une nouvelle carte des limites du pergélisol lors de son extension maximale en Europe de l’Ouest. La carte a ensuite été comparée avec des simulations du pergélisol issues de Modèles Globaux du Climat. Enfin, la troisième partie de cette thèse fournit le premier cadre chronologique pour la fissuration par contraction thermique du sol en France, en s’appuyant sur la datation par luminescence optiquement stimulée (OSL) du remplissage sableux des coins<br>During the Mid to Late Pleistocene, the land area affected by periglacial conditions expanded and contracted repeatedly over large surfaces in mid-latitude Western Europe. In such environments, permafrost or deep seasonal freezing of the ground formed typical features, which have been the subject of abundant research by geomorphologists. In particular, researchers attempted to reconstruct the maximal extent of Pleistocene permafrost based on field evidence. Although most reconstructions suggest that permafrost spread over part of France during the coldest periods of the Pleistocene, there is no agreement regarding the land surface affected. This is mainly due to the scarcity of field data used for mapping and to the questionable palaeoclimatic significance of certain periglacial features. In addition, permafrost modelling during the Last Glacial Maximum using Global Climate Models does not seem consistent with field data. To solve these issues, a database of Pleistocene periglacial features has been compiled from a review of academic literature and unpublished reports, the analysis of aerial photographs and new field surveys. Polygons, soil stripes, ice-wedge pseudomorphs, sand wedges and composite wedge pseudomorphs were included in the database together with their geographic coordinates, geological context, description and references. The distribution of the identified features was analysed with a GIS software and clearly indicates that large areas in France were affected by periglaciation, apart from the southwesternmost part of France and the Languedoc. Ice-wedge pseudomorphs do not extend south of 47°N which indicates that widespread discontinuous permafrost did not affect the land south of the Paris basin. The exclusive presence of sand wedges with primary infill between 45 and 47°N, mainly in the periphery of coversands, suggests that thermal contraction cracking of the ground occurred together with sand drifting in a context of deep seasonal frost or sporadic discontinuous permafrost, unfavourable for the growth of significant ground-ice bodies. However, the description of composite-wedge pseudomorphs below 47°N indicates that at least locally ice veins formed probably during exceptionally cold winters. To provide a chronological framework for thermal contraction cracking single-grain OSL measurements were performed on 33 samples taken in the sandy infilling of sand-wedges and composite-wedge pseudomorphs. Results suggest that multiple events were recorded within wedges. The extraction of the datasets using the Finite Mixture Model, which was developed to analyse statistically data comprising multiple components, allowed calculating 86 ages. These age estimates show that wedge activity in France occurred at least 11 times over the last 100 ka. The most widespread events of thermal contraction cracking occurred between ca. 30 and 24 ka (Last Permafrost Maximum) and are concomitant with periods of high sand availability (MIS 2). Although most phases of sand-wedge growth correlate well with known Pleistocene cold periods, the identification of wedge activity during late MIS 5 and the very beginning of the Holocene strongly suggests that sand-wedges do not only indicate permafrost but also deep seasonal ground freezing in the context of low winter insolation. The previously published young ages yielded by North-European sand-wedges likely result from poor record of periglacial periods concomitant with low sand availability and/or age averaging inherent to standard luminescence methods. This work allowed us to propose a map of the maximum extent of Late Pleistocene permafrost in France, which partially reconciles field data with palaeoclimatic simulations. The remaining discrepancies may be linked with a potential time lag between the Last Permafrost Maximum (c. 31–24 ka) and the Last Glacial Maximum (21 ka) and to the already identified warm winter bias of the models

Thesis (MMil (Computer Information Systems))--University of Stellenbosch, 2005.<br>Since the 1940s, the evaluation of information systems has been the topic of many authors’ research. When taking into account the amount of resources invested in an organisation’s information systems, especially in the present fiscal conditions, then the evaluation of an information system’s success is imperative. Traditionally, monetarybased evaluation measures were used to evaluate the success of an information system, however, these types of measures were found to be inadequate in their attempt to measure the complexity of information systems successfully. Surrogate measures, such as the user’s satisfaction with the information system, were developed to replace monetary-based evaluation measures. These forms of measures are often perceptual by nature and usually encompass the different stakeholders involved in the information system.

L'histoire géologique crétacée-éocène des Ori Valtou peut être scindée en deux périodes. La première période connue depuis le Jurassique terminal, se poursuit jusqu'au Santonien: de puissants dépôts carbonatés de plate-forme s'y forment en contexte tranquille, caractérisant une évolution de type bahamien. La seconde période est inaugurée par un épisode diastrophique d'âge santonien à campanien, responsable de:―la création d'un faisceau faillé partageant longitudinalement le massif,―l'ablation d'une partie des sédiments antérieurement déposés à l'Ouest de ce faisceau,―la création d'une dépression discontinue à l'Est. Si la sédimentation est continue vers l'Est, c'est progressivement au cours du Campanien-Maastrichtien que des récifs vont s'installer vers l'Ouest, avant l'émersion généralisée finicrétacée. La période paléocène-éocène voit encore la différenciation des compartiments et de nouvelles instabilités, répliques atténuées du phénomène crétacé. Après avoir montré que des différenciations longitudinales comparables se sont produites au cours du Crétacé supérieur au sein des «plates-formes adriatico-égéennes» des Dinarides et de l'Apennin, on trouve dans l'affrontement qui se produit alors entre l'Apulie et l'Europe le moteur probable de coulissements longitudinaux. Ici, des phénomènes de transpression auraient produit l'extrusion d'une lame occidentale dont la partie supérieure aurait glissé vers le bassin Ionien, engendrant les brèches sénoniennes qui y sont connues; des phénomènes de transtension rendraient compte de la discontinuité de la dépression bordant à l'Est le faisceau d'accidents longitudinaux. La succession dans le temps de ces deux types de phénomènes peut rendre compte de l'ensemble des faits établis

This work includes the theory of circuit breaker construction and is focused mainly on overload function. It mainly deals with electronic circuit breakers, i.e. equipped with an electronic trip unit. The work is focused on the part of trip unit - maglatch of trip unit. For the purposes of simulation, the geometric model is created. Maxwell program is used for the simulation. The work describes the options for conditions input which are necessary for simulation. Using the distribution of magnetic field intensity and magnetic flux density in the section of trip unit maglatch is determined by the simulation. Furthermore, the force effects acting on the armature of the maglatch are calculated. Force values and the directions acting on the armature are determined by changing the simulation parameters - shift of the armature and coil current. Simulations are performed both for steady-state and for dynamic simulation – movement of armature is taken into account. The supply source for the maglatch is created by an external circuit.

Actualmente a economia internacional tem apresentado sinais de instabilidade, principalmente nos negócios internacionais. A crise de 2008, que resultou do suprime norte – americano, tem afectado as relações comerciais em todo o globo, originando graves problemas de desenvolvimento socioeconómicos, com maior destaque para os países emergentes. Recentemente estas economias têm sofrido um revés no seu progresso devido a queda abrupta do preço do petróleo, originando graves problemas económicos. Os países ocidentais que mergulharam numa crise profunda têm, principalmente na UE, implementando estratégias de combate à crise nas mais variadas formais. As empresas nacionais de cada nação têm sentido bastantes dificuldades de sustentabilidade e crescimento, tal como de competitividade nos mercados onde estão inseridos. A existência de um leque variado de estratégias anticrise tem permitido às empresas, com destaque para as PME’S, criarem condições para o crescimento económico. Uma das estratégias muito utilizadas para o sucesso empresarial pós-crise tem sido a internacionalização empresarial. A internacionalização poderá ser considerada como uma boa solução para as empresas poderem crescer com a conquista de novos mercados, mercados esses que poderão muitas vezes estar localizados em regiões remotas de difícil acesso. As empresas utilizam cada vez mais a estratégia da internacionalização para obter a captação de mercados que estejam fora do seu circuito natural, e assim possam aceder ao desenvolvimento e crescimento. A internacionalização molda-se em várias formas e princípios de actuação, sendo os mais utilizados, as exportações, as Jointventures, as parcerias, as sociedades e as delegações. Neste estudo, sobre as possibilidades de uma entidade empresarial possa ser fixada num outro país, será focado como directriz de desenvolvimento os factores condicionantes da internacionalização no país de origem. Neste sentido, a temática de estudo a desenvolver será centrada em estratégias de avaliação e critérios relacionados com o sucesso empresarial. A motivação externa, o OLI (Ownership, Location e Internalization) e o Linkage, Leverage e Learning, fazem parte das variáveis independentes desta pesquisa. Estas três variáveis independentes servirão de base metodológica e empírica para uma abordagem categorizada baseada em pilares organizacionais de cada país, facilitando em todos os aspectos no processo e sucesso da internacionalização empresarial.