The use of short columns, higher carrier gas velocity and fast temperature programs in Comprehensive Two-Dimensional Gas Chromatography coupled to Time-of- Flight Mass Spectrometry (GC x GC/TOFMS) technique is expected to increase the speed of analysis up to several orders of magnitude when compared to conventional gas chromatography (GC) or gas chromatography/mass spectrometry (GC/MS). A systematic evaluation of the GC x GC/TOFMS configuration for high-speed applications has received little attention in the literature. The feasibility of High Speed Comprehensive Two-Dimensional Gas Chromatography coupled to Mass Spectrometry (High speed GC x GC/MS) for complex mixtures has been investigated in this thesis. A particular focus was placed on comparing conventional scanning quadrupole mass spectrometry (qMS) with a newly available non-scanning time-of-flight instruments (TOFMS). Experiments were carried out using GC/qMS, GC x GC/qMS, GC/TOFMS and GC x GC/TOFMS both in normal (slow) and fast temperature rates coupled with high frequency modulation in GC x GC. Initially a complex mixture consists of 24 semivolatile compounds was used as the analyte for the above purpose. In the initial experiments parameters like acquisition rate and duty cycle for qMS were determined to evaluate the effectiveness of the instrument for fast analysis. The practical duty cycle value obtained for the qMS was only about 18 % for single ion and one compound at a dwell time of 10 ms in SIM mode. In both high-speed GC/qMS and high-speed GC x GC/qMS techniques only about 40 % of the components in the complex mixture were found to be well separated. The acquisition rate of scanning instruments like qMS is incompatible for fast eluting peaks in high speed GC. TOFMS that has an acquisition rate of several hundred spectra per second offer the potential to define the fast GC peaks accurately. The high quality spectra from TOFMS also enable deconvolution of coeluting peaks in the complex mixtures. The advantage of the automated spectral deconvolution is demonstrated for the identification of the coeluting peaks in the complex mixtures. Coelution of peaks is also observed with highspeed GC/TOFMS technique. The high-speed GC x GC/TOFMS was also tested with two different analyte system ??? A pesticide mixture and platformate (an aromatic mixture) to evaluate the suitability for high-speed analysis of complex mixtures. A poor resolution was observed for the pesticide mixture in the two-dimensional plane and it appeared, as there was nearly no orthogonal separation in the second dimension. The platformate mixture displayed a better two-dimensional separation. Chromatographic peak resolution is not really a primary requirement for locating and identifying the coeluting compounds in high-speed GC x GC/TOFMS technique. However, it was observed that the high-speed GC x GC/TOFMS too faced problem to unscramble the mass spectra of those compounds with similar structure and sharing the same unique masses.

[pt] O funcionamento de detectores fotocondutivos se baseia na geração de corrente elétrica por fotoexcitação de portadores de carga. Neste trabalho, estudamos os diversos processos que contribuem para a geração de corrente em fotodetectores intrabanda (BC) e construímos um método de investigação para revelar, dentre as diferentes possibilidades, os processos que resultam na emissão eletrônica em um dispositivo concreto. Uma vez estabelecida uma metodologia, passamos ao estudo de um caso particular: um fotodetector baseado em pontos e poços quânticos acoplados, com picos de absorção no infravermelho médio. Através da comparação de espectros de absorção e fotocorrente, medidos por espectroscopia de transformada de Fourier, e de simulações computacionais para o cálculo das forças de oscilador, indicamos as transições óticas e os processos de transporte eletrônico envolvidos na fotocondutividade do dispositivo. / [en] The operation of photoconductive detectors is based on the generation of current through photoexcitation of charge carriers. In this work, we study the various processes that contribute to the generation of current in intraband (CB) photodetectors and build a method of investigation to reveal, among the different possibilities, the processes that actually result in electron emission in a particular device. After establishing a methodology, we apply it to a case study, more specifically, a dot-in-a-well (DWELL) photodetector with absorption peaks in the mid-infrared. By comparing absorption and photocurrent FTIR spectra as well as oscillator strength calculations performed by a computer simulation of the structure, we have approached the optical transitions and electron transport processes involved in the device s photoconductivity.

L'application d'un temps de maintien, même de faible durée, lors d'un chargement cyclique, modifie de façon très sensible à la fois le comportement contrainte-déformation et le nombre de cycles à amorçage dans l'alliage base titane TI-6242. Ceci est lié à un régime de fluage cyclique, conduisant à de la déformation progressive d'une part, et à une forte interaction fatigue-temps de maintien pour ce qui concerne le nombre de cycles à amorçage. Les différents phénomènes sont pour le moment assez mal analysés, si bien qu'il n'est pas possible d'effectuer une conception optimale des pièces, de larges marges de sécurité étant nécessaires. Le but du travail est de mieux comprendre les mécanismes locaux qui régissent le comportement et l'amorçage des fissures, dans le but de suggérer des microstructures optimales, et de calibrer des modèles macroscopiques utilisables en bureau d'études. En s'appuyant sur une base expérimentale fournie par Snecma et l'ENSMA, une approche multiéchelles a été mise en place pour représenter les hétérogénéités locales qui ont un rôle significatif sur les comportements observés. Dans les calculs des microstructures, faisant intervenir une étape d'évaluation statistique, on se focalise sur la représentation explicite des ”plumes”, grains de taille exceptionnelle, qui sont à l'origine des premières microfissures en raison du contraste cristallin qu'ils introduisent avec l'environnement. Une revue des différentes configurations de plumes, afin de retenir celles qui sont le plus critique, a été établie. Cette analyse a permis de mettre en évidence la présence de plumes simples, doubles ou triples, les domaines se présentant sous formes de bandes. Les configurations à étudier comportent comme paramètres critiques l'orientation géométrique de la bande par rapport à la direction du chargement macroscopique, mais surtout l'orientation cristallographique au sein de cette (ces) bande(s). Des calculs systématiques ont été effectués afin de mener une étude statistique et de déterminer les configurations les plus sensibles. / The application of a dwell period, even of short length, during a cyclic loading, simultaneously changes the stress-strain behaviour and the number of cycles to failure in a very sensitive way. This phenomenon is connected to a cyclic creep regime, generating progressive deformation, and to a strong interaction between the fatigue process and dwell periods for the number of cycles to failure. All these phenomena are poorly analysed nowadays, so that engineers hardly perform optimal design of the components, since large security margins are necessary. The aim of the work is to better understand the local mechanisms which govern both behaviour and crack initiation, having in view optimal microstructures, and to calibrate manageable macroscopic models for the design department. Using an experimental data set given by Snecma and ENSMA, a multiscale approach has been developed to represent the local heterogeneities that play a significant role on observed behaviour. In the calculations of microstructures that are performed for a statistical evaluation, the focus is made on the explicit representation of the so called "plumes", that are grains of exceptional size, which are at the origin of the first microcracks due to crystal contrast they introduce with the environment. A review of various "plume" configurations is made, in order to investigate the most critical ones. This analysis allowed to shed the light on the presence of simple, double or triple "plumes", the domains being in band shapes. The critical parameters are the geometric arrangement of the band with respect to the direction of the macroscopic loading, but essentially the crystal orientation within this (these) band(s). Systematic calculations were carried out in order to do a statistical study and to determine the most critical configurations.

Cette étude traite de l'impact du vieillissement thermomécanique sur la microstructure et sur les propriétés mécaniques du nouveau superalliage base Nickel pour disque de turbine René 65.Le vieillissement thermique conduit à trois évolutions microstructurales majeures, à savoir la croissance des précipités y' intragranulaires et à la nucléation de particules TCP aux joints de grains accompagnés d'une ségrégation de molybdène. Une méthode innovante basée sur des traitements thermiques adaptés a permis de dissocier les effets de ces deux évolutions microstructurales sur les propriétés en fluage et fatigue-temps de maintien à 700° Cdu René 65. La croissance des précipités y' intragranulaires est majoritairement responsable de l'abattement des propriétés mécaniques. Il s'avère néanmoins que la présence des particules TCP aux joints de grains ainsi que la ségrégation de molybdène affectent également le comportement viscoplastique et la durabilité de l'alliage, contribuant à un abattement supplémentaire des propriétés mécaniques. Ce phénomène est attribué à l'adoucissement localisé de la matrice au voisinage des particules TCP et des joints de grains par la perte d'éléments durcissants de la solution solide y. / This study focused on the impact of thermo-mechanical aging on the microstructure and on the mechanical properties of the new nickel-based superalloy René 65 for turbine disk applications.Thermal aging causes three main microstructural evolutions, namely the intragranular y'-growth, the nucleation of TCP particles at grain boundaries along with a segregation of molybdenurn. An innovative method based on appropriated thermal treatments enabled to dissociate these microstructural evolutions' impacts on the René 65 creep and dwell-fatigue properties at 700°C.The y'-growth is mainly responsible of the overall mechanical proprerties degradation. However, it turns out TCP particles and the molybdenum segregation at grain boundaries also affect negatively the alloy viscoplastic behavior and its durability, contributing to an additional decrease in its mechanical properties. This phenomenon is attributed to the softening of the matrix locally at grain boundaries by solid solution elements depletion in favor of TCP precipitation.

Abstract The Swedish railway has during many years received low customer satisfaction scores. Reasons for this are reliability, service and information concerns. The focus of this master thesis lies on the railway platform. The platform is an important part to the factors above as its information and facilities, which constitute a part of the service before the trip, could contribute in causing delays and reliability issues. This study investigates the behaviour of passengers on railway platforms and the effect that information, seats and entrances along the platform has on that behaviour. The goal is to find advantages and disadvantages and propose improvements in a Swedish setting. Platforms and trains that have been studied are in Stockholm, Sweden and Tokyo, Japan. Platform distributions and individual behaviour on the platforms are recorded with three different and relatively easy methods. Results of the Swedish study show aggregate trends where passengers tend to cluster around entrances and seats. Many Swedish passengers do not believe themselves to have enough information to know where their car will stop. These passengers do mostly not know that information exist and on average stand much further away from their closest door, when the train arrives, compared to passengers that believe themselves to know where their car will stop along the platform. The results of the Japanese study show that almost all passengers stand close to their door. From the findings in not only this, but also other studies, four aggregate properties in order to get better railway platforms are finally presented. These properties are reliability, clarity and availability of information and good location of seats and other facilities. Suggestions for tangible improvements for the Swedish railway platforms are finally given. Among these improvements are new information screens and standardized information and stopping position of trains.

No description available.

<p>There is a growing need to understand the deformation mechanisms in titanium alloys due to their widespread use in the aerospace industry (especially within gas turbine engines), variation in their properties and performance based on their microstructure, and their tendency to undergo premature failure due to dwell and high cycle fatigue well below their yield strength. Crystal plasticity finite element (CPFE) modeling is a popular computational tool used to understand deformation in these polycrystalline alloys. With the advancement in experimental techniques such as electron backscatter diffraction, digital image correlation (DIC) and high-energy x-ray diffraction, more insights into the microstructure of the material and its deformation process can be attained. This research leverages data from a number of experimental techniques to develop well-informed and calibrated CPFE models for titanium alloys at multiple length-scales and use them to further understand the deformation in these alloys.</p> <p>The first part of the research utilizes experimental data from high-energy x-ray diffraction microscopy to initialize grain-level residual stresses and capture the correct grain morphology within CPFE simulations. Further, another method to incorporate the effect of grain-level residual stresses via geometrically necessary dislocations obtained from 2D material characterization is developed and implemented within the CPFE framework. Using this approach, grain level information about residual stresses obtained spatially over the region of interest, directly from the EBSD and high-energy x-ray diffraction microscopy, is utilized as an input to the model.</p> <p>The second part of this research involves calibrating the CPFE model based upon a systematic and detailed optimization routine utilizing experimental data in the form of macroscopic stress-strain curves coupled with lattice strains on different crystallographic planes for the α and β phases, obtained from high energy X-ray diffraction experiments for multiple material pedigrees with varying β volume fractions. This fully calibrated CPFE model is then used to gain a comprehensive understanding of deformation behavior of Ti-6Al-4V, specifically the effect of the relative orientation of the α and β phases within the microstructure.</p> <p>In the final part of this work, large and highly textured regions, referred to as macrozones or microtextured regions (MTRs), with sizes up to several orders of magnitude larger than that of the individual grains, found in dual phase Titanium alloys are modeled using a reduced order simulation strategy. This is done to overcome the computational challenges associated with modeling macrozones. The reduced order model is then used to investigate the strain localization within the microstructure and the effect of varying the misorientation tolerance on the localization of plastic strain within the macrozones.</p>

Ce travail analyse les recompositions territoriales que produisent l’augmentation et la diversification des usages sportifs des forêts urbaines. La thèse interroge conjointement les demandes et les usages des populations urbaines, la manière dont ils s’ajustent à des choix d’équipement et à des formes de gestion. La thèse rend compte des déterminations réciproques des cultures, des rapports sociaux et des rapports spatiaux à l’échelle d’une métropole, Rouen, dont la ceinture verte est classée « Forêt d’Exception® » et dont la démarche gestionnaire s’avère relativement pionnière. Le corpus comprend 43 entretiens semi-directifs, divers documents (articles de presse, bulletins d’information, rapports d’activités, etc.), ainsi que de nombreuses données obtenues par questionnaire. Ces dernières ont été produites à l’échelle de la métropole (n=5700), des quartiers de lisière (n = 661) et des pratiques (n=334).L’analyse, multiscalaire, révèle le fonctionnement de médiations territoriales originales, qui sont aussi des analyseurs de choix. La diversité des usages dévoile en premier lieu des territoires du quotidien et des manières d’habiter très différenciées. Leur émergence récréative permet également d’observer, à travers des profils de pratiquants, les recompositions des formes sportives de la vie urbaine contemporaine. À l’heure du numérique et au croisement des logiques de la socialisation (traces et images de soi), de l’événementiel (développement des fun runs) et de l’affirmation d’un échelon politique « métropolitain », on analyse enfin comment ces formes et ces logiques de communication affectent la prise en charge de ces espaces naturels, qu’elles tendent à constituer en « stations ». / This work examines territorial recomposition produced by augmentation and diversification of urban forest outdoor recreation. The thesis interrogates jointly claim and practice and residential ‘choices’, choices in terms of cities and space inside cities. We south to elucidate the reciprocal determination of the various cultures, social relationships and spatial relations in Rouen metropolis (France). Rouen green belt is classified “Exceptional Forest ®” and the forest management is relatively pioneer. The corpus contains 43 semi-structured interviews, documents from several sources (departments of urban planning, administrative reports, newspapers articles, etc.) and several surveys collected by the scale of Rouen metropolis (N=5700), forest-fringe residents (N=661) and outdoor recreation practitioners (N=334). A multi-scale approach reveal how territorial mediations operate as a decision analyser. Practice diversity reveals “territories of the everyday” and different ways of living. Outdoor recreation emergence also allows to observe the urban life physical activities restructuration through the description of the type of practitioners. At the crossing of the logic of socialization (tracks, self-images), the logic of event management (fun runs development) and the appearance of a new metropolitain political scale we analysed how communication affects natural landscape and tend to turn them into “resort”.

Schnellläuferstrategien sind Lagerstrategien, welche den Durchsatz von Lagern durch geeignete Wahl der Lagerorte im Lager steigern. Die verschiedenen existierenden Strategien wurden bisher uneinheitlich beschrieben und umgesetzt. Aussagen zu Durchsatzsteigerungen fallen schwer. Die existierenden Strategien werden systematisiert und als Vergleichsbasis für die neue Strategie &amp;quot;Dynamische Zonierung&amp;quot; herangezogen. Die &amp;quot;Dynamische Zonierung&amp;quot; ist dabei sowohl die einfachste als auch die leistungsfähigste Schnellläuferstrategie. Dafür sorgt die konsequente Anwendung zweier Verfahren, welche bereits einzeln sinnvoll sind, aber erst gemeinsam ihr volles Potential entfalten: Erstens erübrigt die Abbildung der Verweildauerverteilung auf die Fahrzeitverteilung jegliche Zonierung. Damit entfallen die Aufwände für Planung und Berechnung von Zonengrenzen und -zuordnungen. Gleichzeitig kann so die bei Zonenbildung unvermeidliche Abbildungsunschärfe beseitigt werden. Eine von einer optimalen Zuordnung abweichende Lagerortwahl resultiert nun ausschließlich aus Prognosefehlern. Zweites stellt die lagereinheitsbasierte Verweildauerbetrachtung die korrekte Umsetzung des als optimal nachgewiesenen Cube-Per-Order-Kriteriums dar. Ohne Zwang zur Zonenbildung fehlen die der Verwendung lagereinheitsbasierter Verweildauern sonst entgegenstehenden algorithmischen Mehraufwände. Dass auch die Prognose lagereinheitsbasierter Verweildauern für Teile des Sortimentes nicht zu Mehraufwand sondern zur Vereinfachung des Verfahrens führt, spricht zusätzlich für die lagereinheitsbasierte Betrachtung. Auch bei herkömmlicher artikelorientierter Betrachtungsweise kann die Dynamische Zonierung dadurch Leistungsvorteile herausarbeiten. / Turnover-based storage strategies are strategies in warehousing which increase the system throughput by choosing favorable storage locations. Existing strategies have been described and implemented inconsistently when compared to each other. Statements on strategy gains are difficult. Therefore a categorization of turnover-based strategies is devised. The existing strategies serve as basis of comparison for the new strategy &amp;quot;Dynamic Zoning&amp;quot;. &amp;quot;Dynamic Zoning&amp;quot; proves to be the simplest turnover-based strategy while giving the highest performance at the same time. This is accomplished by combining two methods. These methods are reasonable when used separately, but only reach their full potential when used together. First, mapping the dwell time (duration of stay) probability distribution to the travel time probability distribution lets zones become obsolete. Efforts to plan and calculate zones can be avoided and the inevitable imprecision when mapping to zones vanishes. Any deviation from the optimal storage location now results from errors in estimation. Second, dwell times must be based on unit loads which is the correct application of the cube-per-order-criterion for optimality. Without the need to use zones this does not result in extra effort to apply the strategy. For a part of the assortment the estimation of unit load dwell times is simpler than before too, making unit load dwell times even more appealing. However, even when using conventional article based dwell time estimates the strategy &amp;quot;Dynamic Zoning&amp;quot; results in higher performance than other strategies.

[pt] Esta pesquisa compreende como a religião afro-brasileira Candomblé se relaciona com o espaço físico em que acontece no mundo. Este lugar é chamado, carinhosamente, Roça. Estabelecendo a relação entre a cultura negra afrodiaspórica e a Arquitetura, revela-se uma forma muito particular de habitar. A religião, culturalmente, é um campo fértil de simbologias dessa existência, e contém aspectos cheios de significados do homem, do divino e do lugar. Dentre as religiões afrosiaspóricas, o Candomblé tem importância fundamental. Uma comunidade de resistência e de produção cultural, moldada pela mutabilidade, movimento e hibridação da diáspora negra. Buscou-se compreender os significados, os sentidos e as definições de cada elemento que compõe o universo da Roça de Candomblé: os elementos pré-existentes, construídos, naturais e as relações destes com a comunidade religiosa que compõe, com os deuses e ancestrais, os habitantes deste espaço metafísico afro-brasileiro. A dissertação foi desenvolvida através de grande revisão bibliográfica, e a pesquisa de campo etnográfica, com o processo de iniciação do autor no terreiro de Candomblé Ilê Axé Icimimó Aganju Didê, na cidade de Cachoeira, Bahia. Esse fato abre uma comunicação específica com a comunidade religiosa do Icimimó. A ideia é fazer da participação, um instrumento de conhecimento, despedaçando a dicotomia observador-objeto de observação. Neste processo são produzidos desenhos, plantas, arquivos fotográficos e entrevistas. Tecendo esta grande teia de referências se revela um novo Habitar no mundo. / [en] This research seeks to understand how the Afro-Brazilian religion Candomblé relates to the physical space in which it takes place in the world. This place is affectionately called Roça. Establishing the relationship between Afro-Diasporic black culture and Architecture, a very particular way of inhabiting is revealed. Religion, culturally, is a fertile field of symbology of this existence, and contains aspects full of meanings of man, the divine, and the place. Among black religions, Candomblé is of fundamental importance. A community of resistance and cultural production, shaped by the mutability, movement, and hybridization of the black diaspora. We sought to understand the meanings, senses, and definitions of each element that makes up the universe of Roça of Candomblé: the pre-existing, built, natural elements and their relationships with the religious community that composes, together with the gods and the ancestors, the inhabitants of this Afro-Brazilian metaphysical space. The dissertation was developed through a major bibliographic review, and ethnographic field research, with the author s initiation process in the terreiro of Candomblé Ilê Axé Icimimó Aganju Didê, in the city of Cachoeira, Bahia. This fact opens a specific communication with the religious community of Icimimó. The idea is to make participation an instrument of knowledge, breaking the observer-observation dichotomy. In this process, drawings, plans, photographic files and interviews are produced. Weaving this great web of references reveals a new Dwelling in the world.