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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.
81

Transgressions et croisements : le cas de l'adolescent fugueur chez Leïla Sebbar

Aissani, Louiza 09 1900 (has links)
L’objectif de ce mémoire est de rendre compte d’une figure particulièrement dynamique dans l’écriture de Leïla Sebbar, celle de l’adolescent fugueur. Mohamed dans Le Chinois vert d’Afrique (1982) et Shérazade dans Shérazade, 17 ans, brune, frisée, les yeux verts (1984), personnifient une réalité autre que celle accolée aux jeunes descendants de l’immigration maghrébine (surtout algérienne), partagés entre les codes culturels du pays d’origine et ceux du pays de naissance. L’hybridité des personnages et leur mobilité aléatoire permettent de réévaluer les discours sociaux dominants émis en France, pays tiraillé entre les aspirations d’unité nationale et l’histoire coloniale. Le premier chapitre fera état du contact des fugueurs avec la représentation picturale et sa place dans la constitution de leur identité. À la lumière de ces observations, la seconde partie du travail se penchera sur la prise de conscience du regard de l’Autre et le questionnement de l’image préconçue de l’adolescent de banlieue inculte en mal d’insertion sociale. La déconstruction de ce cliché permettra dans le troisième chapitre d’aborder la réappropriation de l’objet culturel par les fugueurs, procédant à une véritable démocratisation de la culture élitiste. Le quatrième chapitre sera enfin consacré au mouvement des fugueurs dans l’espace et dans le temps. Nous y verrons comment les fugueurs, intermédiaires entre la ville et sa banlieue mais aussi entre le paradis perdu du pays d’origine et le désarroi des parents immigrés, provoquent la relecture de l’histoire des générations passées tout en gardant un œil critique sur l’avenir. / The purpose of this master’s thesis is to study the dynamic figure of the runaway in the writing of Leïla Sebbar. Mohamed in “Le Chinois Vert d’Afrique” (1982) and Shérazade in “Shérazade, 17 ans, brune, frisée, les yeux verts” (1984), personifie a reality that the young descendants of the North African immigration must encounter, torn between the cultural codes of the country of origin and the country of birth. The blend of the characters’ culture and their constant mobility reassess the dominant social discourse during a time when France was torn between the aspirations of a national unity and colonial history. The first chapter examines the cultural blend of the runaways with the pictorial representation and its place in the formation of the young protagonists’ identity. In light of these observations, the second part of the thesis will focus on the characters’ awareness of the Other’s perception. The stereotypical suburban teenager lacking culture resulting in the character feeling out of place is being questioned. The breakdown of the “cliché” in the third chapter will address the importance of culture by characters, allowing for a democratization of an upper class culture. The fourth chapter is devoted to the movement of the runaways in space and time. Between the city and its suburbs, the lost paradise that Algeria represents, and the distress of the parents that have left their beloved country, the last part of this study will focus on the characters’ contribution to the rewriting of the history of past and future generations.
82

台灣與印尼雙邊跨境移工政策:以在台逃逸印尼勞工為例 / Coordinating Migrant Labor Policy between Taipei and Jakarta: The Case of Runaway Indonesian Workers

范安曼, Faustina, Anselma Unknown Date (has links)
由於印尼為世界上人口最多的國家之一,因此憑藉著此一優勢印尼成為了勞工輸出大國,但是非常多的印尼勞工在外國工作時面臨虐待,因而產生了不少問題,另一方面,台灣是印尼勞工們選擇工作的優先地,主要原因有三個,第一為較高的薪水,第二為較好的生活品質及良好的工作環境,第三不公平對待相較於他國較少發生,儘管如此台灣政府仍面臨著管理外籍勞工的問題,特別是逃逸的外籍勞工的問題,而在台灣的逃逸外勞比例中,印尼勞工占了最高比例。 先前的研究主要在於分析台灣的逃逸外勞現象,並且把此一現象歸因於台灣的移工政策所造成,但是現有的研究主要是針對菲律賓的勞工而不是印尼勞工,因此對於印尼逃逸勞工現象研究則相較較少。 考慮到外籍勞工議題涵蓋的層面多元,如多方的參與者,因此本篇論文將專注於闡述與探討負責輸出勞工及輸入勞工國家的角色及政策。本篇論文主要分為兩部份,第一部分,由於台灣的移工政策對於外國勞工非常嚴格,因此台灣的移工政策造成了印尼勞工過多的負擔,第二台灣和印尼政府無效率的配合,兩國政府只專注於表面並無徹底了解並從其根本解決勞工問題,這兩項因素造成了高比率的逃逸印尼勞工問題,除此之外,本篇論文亦將包含清楚的台灣政府和印尼政府的勞工政策發展,為了更清楚了解此一議題,本篇論文也向移民署收容所作問卷調查,訪問避難所的逃逸勞工,和研究台印勞工現象的專家學者們進行團體討論,本篇分析結果來自問卷調查及訪問,並將此一結果與現有的印尼及台灣政府的政策與合作進行分析。 / As one of the most populous country in the world, Indonesia’s predominance is sending its human resources to work abroad. However, many Indonesian overseas workers encounter mistreatment during their work time which leads to several arising problems. On the other hand, Taiwan has become one of the preferred destination countries due to three reasons; higher salary, better living and working conditions, and low mistreatment cases compare to other destination countries. Despite that, Taiwan government still encounters issues in managing foreign workers. Runaway foreign worker is a major issue in Taiwan’s labor market and Indonesian workers are accounted as the highest runaway foreign workers in Taiwan. Previous researches have been conducted to analyze the phenomenon of runaway foreign workers in Taiwan and most of them addressed Taiwanese guest worker policy as the major reason. Research on runaway Indonesian workers in particular is very limited as most of the existing researches focused on Filipinas workers. Taking into account that foreign workers issue is a multi-faceted phenomenon which involves various actors, this thesis acknowledges the roles and policies from both sending and host states. Therefore this thesis delivers two arguments. First, Taiwan’s guest worker policy has put excessive burden on Indonesian workers as Taiwan employs highly restrictive policy towards foreign workers. Second, Indonesia and Taiwan’s ineffective cooperation is unable to address the existing runaway Indonesian workers issue as it emphasizes more on scratching the surface than dealing with the root causes. These two variables have inadvertently contributed to the high number of runaway Indonesian workers. In addition, this thesis also delivers a clear labor policy development in Indonesian and Taiwan government to understand each institution’s in-take related to labor issues. In order to provide comprehensive findings, this thesis conducts survey with the Indonesian runaway workers in Detention Center, interview with the runaway Indonesian workers in shelters, and focus group studies with Indonesian and Taiwanese experts who are dealing with such phenomenon. The analysis is drawn from the results of survey and interview, and then is connected to the current Indonesian and Taiwanese policies and cooperation in addressing particular issue.
83

Quenching runaway reactions : hydrodynamics and jet injection studies for agitated reactors with a deformed free-surface

Torré, Jean-Philippe 06 December 2007 (has links) (PDF)
To quench a thermal runaway reaction in a chemical rector, an efficient approach is the introduction of a small quantity of a liquid inhibiting agent, named a “killer”, into the mixing vessel. In this thesis, an experimental approach has been coupled tightly with numerical modelling using Computational Fluid Dynamics (CFD). The first part of this thesis is devoted to a study of the hydrodynamics of partially-baffled mixing vessels, including the free-surface deformation caused by the central vortex. The use of an inhomogeneous, multiphase approach allowed simulation of the free-surface deformation. The capability of this novel method was demonstrated by very good agreement between the numerical predictions and experimental data. In the second part, liquid jet injection at the free-surface was coupled with the vessel hydrodynamics. Numerical results, obtained using an Eulerian-Lagrangian approach, have again shown good agreement with experimental data. These results allowed the jet trajectory to be modelled and its penetration into the agitated vessel was quantified. New mixing criteria were introduced that are specific to this application. Finally, the numerical methods validated at the pilot scale were applied at the industrial scale and allowed the proposal of practical improvements to the safety of the synthesis reactors studied
84

Caractérisation de la nature physique du rejet d’un évent en cas d’emballement de réaction : étude du modèle de désengagement / Characterization of the physical nature of emergency relief vent flow in case of runaway reaction : study of the disengagement model

Xu, Jie 09 October 2017 (has links)
Dans l’industrie chimique, la majorité des réacteurs est équipée d’un dispositif « évent de sécurité » permettant d’éviter leur éclatement en cas de surpression accidentelle conséquente à un emballement. La nature physique du rejet (gazeux ou diphasique gaz-liquide) influe fortement sur la taille requise de l’évent. L’objectif de notre étude est de connaitre mieux le comportement de l’écoulement (désengagement) en cas d’un emballement de réaction et de prédire la nature du rejet (mono ou diphasique) notamment à l’échelle industrielle.Une étude expérimentale d’une réaction d'estérification fut réalisée dans un réacteur en verre de 0,5 l afin de visualiser la nature de l’écoulement et de mesurer la fraction de vide moyenne (ᾱ) lors de l’emballement de réaction. Une étude paramétrique fut effectuée de façon à identifier, pour le régime d'écoulement et la transition, les paramètres clés : la viscosité et l’agitation. Un calorimètre pseudo-adiabatique (VSP2) fut utilisé pour étudier la thermodynamique de l’emballement d’estérification. Les bilans massique et énergétique ont été utilisés pour calculer la vitesse superficielle de la vapeur (jg,max). En outre, le jg, max fut calculé aussi à partir de différentes corrélations, issues d’études en colonne à bulles. Une comparaison entre les résultats obtenus a montré l’inadéquation de ces corrélations pour un système réactif. Une carte de régime pour un système réactif a été construite pour la première fois (jg,max versus ᾱ, combinée à l'observation du régime d'écoulement dans le réacteur), avec une méthodologie pour la prédiction de la nature du rejet en cas d’emballement. / In chemical industry, most reactors are equipped with an emergency relief vent to prevent bursting in case of accidental overpressure due to a runaway reaction scenario. The physical nature of the vent release (gas phase or gas-liquid) strongly influences the necessary vent size. The objective is to enhance the knowledge on the flow behavior (disengagement) during a runaway reaction and to be able to predict the nature of the vent flow (1 or 2-phase) namely at industrial scale.Experiments of esterification were done in a 0.5 l glass reactor in order to visualize the flow pattern (hydrodynamic) and to measure the average void fraction (ᾱ) during the runaway. A parametric study was carried out to identify the key parameters onto the flow pattern and transition, they were: the viscosity and the stirring. A pseudo-adiabatic calorimeter (VSP2) was used to study the runaway P and T profile and the kinetic of the esterification. The thermodynamic data and the mass & heat balances were used to calculate the superficial vapor velocity (jg,max). Furthermore, this jg,max was also calculated from different correlations, obtained from bubble column research. A comparison showed the incorrectness of using these correlations for a reactive system. A flow pattern map (jg,max versus ᾱ combined with the observation of the flow pattern,) for a reactive system was built up for the first time together with a methodology to predict the vent flow nature.
85

Modeling and Simulation Tools for Aging Effects in Scaled CMOS Design

January 2014 (has links)
abstract: The aging process due to Bias Temperature Instability (both NBTI and PBTI) and Channel Hot Carrier (CHC) is a key limiting factor of circuit lifetime in CMOS design. Threshold voltage shift due to BTI is a strong function of stress voltage and temperature complicating stress and recovery prediction. This poses a unique challenge for long-term aging prediction for wide range of stress patterns. Traditional approaches usually resort to an average stress waveform to simplify the lifetime prediction. They are efficient, but fail to capture circuit operation, especially under dynamic voltage scaling (DVS) or in analog/mixed signal designs where the stress waveform is much more random. This work presents a suite of modelling solutions for BTI that enable aging simulation under all possible stress conditions. Key features of this work are compact models to predict BTI aging based on Reaction-Diffusion theory when the stress voltage is varying. The results to both reaction-diffusion (RD) and trapping-detrapping (TD) mechanisms are presented to cover underlying physics. Silicon validation of these models is performed at 28nm, 45nm and 65nm technology nodes, at both device and circuit levels. Efficient simulation leveraging the BTI models under DVS and random input waveform is applied to both digital and analog representative circuits such as ring oscillators and LNA. Both physical mechanisms are combined into a unified model which improves prediction accuracy at 45nm and 65nm nodes. Critical failure condition is also illustrated based on NBTI and PBTI at 28nm. A comprehensive picture for duty cycle shift is shown. DC stress under clock gating schemes results in monotonic shift in duty cycle which an AC stress causes duty cycle to converge close to 50% value. Proposed work provides a general and comprehensive solution to aging analysis under random stress patterns under BTI. Channel hot carrier (CHC) is another dominant degradation mechanism which affects analog and mixed signal circuits (AMS) as transistor operates continuously in saturation condition. New model is proposed to account for e-e scattering in advanced technology nodes due to high gate electric field. The model is validated with 28nm and 65nm thick oxide data for different stress voltages. It demonstrates shift in worst case CHC condition to Vgs=Vds from Vgs=0.5Vds. A novel iteration based aging simulation framework for AMS designs is proposed which eliminates limitation for conventional reliability tools. This approach helps us identify a unique positive feedback mechanism termed as Bias Runaway. Bias runaway, is rapid increase of the bias voltage in AMS circuits which occurs when the feedback between the bias current and the effect of channel hot carrier turns into positive. The degradation of CHC is a gradual process but under specific circumstances, the degradation rate can be dramatically accelerated. Such a catastrophic phenomenon is highly sensitive to the initial operation condition, as well as transistor gate length. Based on 65nm silicon data, our work investigates the critical condition that triggers bias runaway, and the impact of gate length tuning. We develop new compact models as well as the simulation methodology for circuit diagnosis, and propose design solutions and the trade-offs to avoid bias runaway, which is vitally important to reliable AMS designs. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2014
86

Test particles dynamics in 3D non-linear magnetohydrodynamics simulations and application to runaway electron formation in tokamak disruptions / Dynamique de particules tests dans des simulations de magnétohydrodynamique non-linéaire 3D et application à la génération d'électrons découplés dans les disruptions des tokamaks

Sommariva, Cristian 18 December 2017 (has links)
La thèse étudie la dynamique des Electrons Découplés (DE) dans une disruption plasma déclenchée par injection massive de gaz dans le tokamak JET et simulée par le code JOREK. Cette investigation est permise par l’implémentation d’un module de suivi des particules tests relativistes dans JOREK. L’étude montre que les électrons peuvent ‘survivre’dans le chaos magnétique caractérisant la phase dite de ‘Disjonction Thermique’ (DT) de cette disruption (simulée) grâce à la reformation des surfaces magnétiques fermées. Deuxièmement, l’accélération des électrons causée par les champs électriques dus aux fluctuations magnétohydrodynamiques (MHD) pendant la DT est analysée. Cela montre que les électrons peuvent être accélérés par ces champs et devenir DE, après reconfinement, pendant la phase dite de ‘Disjonction de Courant’. Une étude préliminaire sur les dépendances entre le courant des DE et l’activité MHD dans les expériences de disruption du tokamak ASDEX Upgrade est également reportée. / In view of better understanding Runaway Electron (RE) generation processes during tokamak disruptions, this work investigates test electron dynamics during a JET disruption simulated with the JOREK code. For this purpose, a JOREK module computing relativistic test particle orbits in the simulated fields has been developed and tested. The study shows that a significant fraction of pre-disruption thermal electrons remain confined in spite of the magnetic chaos characterizing the Thermal Quench (TQ) phase. This finding, which is related to the prompt reformation of closed flux surfaces after the TQ, supports the possibility of the so-called “hot tail” RE generation mechanism. In addition, it is found that electrons may be significantly accelerated during the TQ due to the presence of strong local electric field (E) fluctuations related to magnetohydrodynamic (MHD) activity. This phenomenon, which has virtually been ignored so far, may play an important role in RE generation. In connection to this modelling work, an experimental study on ASDEX Upgrade disruptions has been performed, suggesting that strong MHD activity reduces RE production.
87

Estudo numérico, implementação computacional e verificação experimental do fenômeno da fuga térmica em materiais viscoelásticos / A numerical study computational implementation and experimental verification of the thermal runaway phenomenon in viscoelastic materials

Rodovalho, Luiz Fernando Ferreira 05 September 2014 (has links)
Fundação de Amparo a Pesquisa do Estado de Minas Gerais / This work is dedicated to the development of a strategy for numerical-computational modeling and experimental verification of the self-heating phenomenon in viscoelastic materials with emphasis on the thermal runaway phenomenon taking into account the combined effects of dynamic loads and static preloads. The methodology of modeling by finite element allows us to consider the influence of frequency, temperature and static preload on the self-heating phenomenon of the linear viscoelastic materials. For this purpose, modifications are made that allow thermomechanical analysis of more complex viscoelastic structures, in addition the evaluation of introducing metal inserts in bulk material for reducing effects of self-heating. The validation of the proposed model and the identification of the physical parameters of thermal efficiency and heat transfer by natural convection, initially unknown, are obtained by comparison of the results of numerical simulations with the corresponding obtained through experimental tests for a specimen formed by a translational viscoelastic joint. The curve-fitting procedure is formulated as an inverse optimization problem through use of the Firefly Algorithm for minimizing the objective function defined as the square difference between the temperatures obtained from the simulations and the corresponding generated by the tests for each time instant. The accuracy and limitations of the model are evaluated by comparing the experimental and simulated temperature profile, allowing to verify the numerical evidence and the qualitative consistence of the results obtained with reported in the literature for the thermal runaway phenomenon for simple devices without effect preload. / Este trabalho é dedicado ao desenvolvimento de uma estratégia de modelagem numéricocomputacional e verificação experimental do fenômeno do autoaquecimento de materiais viscoelásticos com ênfase no fenômeno da fuga térmica levando-se em conta os efeitos combinados de cargas dinâmicas e pré-cargas estáticas. A metodologia de modelagem por elementos finitos permite considerar a influência da frequência, da temperatura e da pré-carga estática no fenômeno do autoaquecimento de materiais viscoelástico lineares. Para tanto, são feitas modificações que permitem a análise termomecânica de estruturas viscoelásticas mais complexas, além da avaliação da introdução de insertos metálicos no volume do material para a redução dos efeitos do autoaquecimento. A validação do modelo proposto e a identificação dos parâmetros físicos de rendimento térmico e de transferência de calor por convecção natural incialmente desconhecidos, são obtidos através da confrontação dos resultados das simulações numéricas com os correspondentes obtidos via ensaios experimentais para um corpo de prova formado por uma junta viscoelástica translacional. O procedimento de ajuste de curvas é formulado como um problema inverso de otimização via emprego da técnica Colônia de Vagalumes para a minimização da função objetivo definida como sendo a diferença quadrática entre as temperaturas obtidas das simulações e as correspondentes geradas pelos ensaios para cada instante de tempo. A precisão e as limitações do modelo são avaliadas pela comparação dos perfis simulados e experimentais de temperatura, possibilitando confirmar as evidências numéricas e a consistência qualitativa dos resultados obtidos com o reportado na literatura para o fenômeno da fuga térmica para dispositivos mais simples e sem o efeito da pré-carga. / Mestre em Engenharia Mecânica
88

Compréhension et modélisation de l'emballement thermique de batteries Li-ion neuves et vieillies / Understanding and modeling of thermal runaway events pertaining to new and aged Li-ion batteries

Abada, Sara 14 December 2016 (has links)
Les batteries lithium-ion s'affichent comme de bons candidats pour assurer le stockage réversible de l'énergie électrique sous forme électrochimique. Toutefois, elles sont à l'origine d'un certain nombre d'incidents aux conséquences plus ou moins dramatiques. Ces incidents sont souvent liés au phénomène d'emballement thermique. La sécurité des batteries Li-ion représente par conséquent un enjeu technique et sociétal très important. C'est dans ce contexte que vient s'inscrire ce travail de thèse dans le cadre d'une collaboration entre IFPEN, l'INERIS et le LISE. Une double approche de modélisation et expérimentation a été retenue. Un modèle 3D du comportement thermique a été développé à l'échelle de la cellule, couplant les phénomènes thermiques et chimiques, et prenant en compte le vieillissement par croissance de la SEI sur l'électrode négative. Le modèle a été calibré pour la chimie LFP/C sur deux technologies A123s (2,3 Ah) et LifeBatt (15 Ah), puis validé expérimentalement. Le modèle permet d'identifier les paramètres critiques d'emballement de cellules, il permet également de discuter l'effet du vieillissement sur l'emballement thermique. Grâce à l'expérimentation, les connaissances en termes d'amorçage et de déroulement d'un emballement thermique d'une batterie Li-ion, ont pu être enrichies, en particulier pour les cellules commerciales LFP/C cylindriques A123s, LifeBatt, et pour les cellules NMC/C prismatiques en sachet souple PurePower (30 Ah). Cette étude ouvre de nouvelles possibilités pour améliorer la prédiction des différents événements qui ont lieu lors de l'emballement thermique des batteries Li-ion, à différentes échelles. / Li-ion secondary batteries are currently the preferred solution to store energy since a decade for stationary applications or electrical traction. However, because of their safety issues, Li-ion batteries are still considered as a critical part. Thermal runaway has been identified as a major concern with Li-ion battery safety. In this context, IFPEN, INERIS and LISE launched a collaboration to promote a PhD thesis so called « understanding and modeling of thermal runaway events pertaining to new and aged Li-ion batteries ». To achieve this goal, a double approach with modeling and experimental investigation is used. A 3D thermal runaway model is developed at cell level, coupling thermal and chemical phenomena, and taking into account the growth of the SEI layer as main ageing mechanism on negative electrode. Advanced knowledge of cells thermal behavior in over-heated conditions is obtained particularly for commercial LFP / C cylindrical cells: A123s (2,3Ah), LifeBatt (15Ah), and NMC / C pouch cells: PurePower (30 Ah). The model was calibrated for LFP / C cells, and then it was validated with thermal abuse tests on A123s and LifeBatt cells. This model is helpful to study the influence of cell geometry, external conditions, and even ageing on the thermal runaway initiation and propagation. This study opens up new possibilities for improving the prediction of various events taking place during Li-ion batteries thermal runaway, at various scales for further practical applications for safety management of LIBs.
89

Social learning and stage development applied to resistance to treatment: Probation youth in a residential treatment facility

Bankowski, Linda Joy 01 January 2003 (has links)
The present study focused on male incarcerated youth, ages ranging from twelve to eighteen, in a twenty-four hour care treatment facility. The study attempted to determine what historical factors such as types of crimes committed, length of criminal history, and gang involvement are behavioral indicators of the type of youth who resist treatment. For the study, run away behavior indicated the youth was resistant to treatment.
90

Analýza teplotních dějů uvnitř článku olověného akumulátoru v režimu kyslíkového cyklu / Analysis of thermal processes inside of lead acid battery cell in oxygen cycle regime

Vondrák, Michal January 2013 (has links)
The aim of this thesis is the analysis of thermal processes in lead accumulators with oxygen cycle. The work is explaining the structure and principle of operation of the standard lead-acid battery and lead-acid battery with oxygen cycle. Generally are described thermal action inside a lead battery with oxygen cycle and the different types of heat generated during operation of the battery are discussed in detail. One chapter describes the practical experiments and their results.

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