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Développement d'une approche multi-échelle de modélisation de dispositifs thermoélectriques : application à des systèmes de capteurs sans fils autonomes sur le corps humain / Development of a multiscale approach for thermoelectric devices modelling : application to wearable wireless autonomous sensors systemsBella, Malika 14 December 2016 (has links)
Les dispositifs thermoélectriques, basés sur la conversion d'énergie thermique, offrent des perspectives intéressantes pour le développement de systèmes autonomes. Les principaux défis pour le développement de telles technologies reposent sur l'obtention de dispositifs flexibles, écologiquement et économiquement viables pouvant alimenter des appareils électroniques à faible consommation d'énergie. Le but de cette thèse a donc été de proposer une méthodologie pour l'analyse globale de dispositifs thermoélectriques pour des applications à température ambiante. Dans un premier temps, une approche multi-échelle pour la modélisation de dispositifs thermoélectriques a été développée. A cet effet, trois niveaux d'abstraction ont été considérés. A l'échelle du système, un modèle compact a été développé afin d'évaluer les performances du dispositif dans son environnement. A l'échelle du dispositif, des prototypes virtuels de TEG ont été évalués par le biais de la simulation numérique. A l'échelle des matériaux, la DFT combinée à une approche semi-classique basée sur l'équation de transport de Boltzmann ont été utilisées afin de calculer les propriétés électroniques. La tétraédrite et la famatinite ont été sélectionnées en raison de leurs propriétés prometteuses à température ambiante ainsi que de leur abondance et faible coût. Dans un second temps, des travaux expérimentaux sur la synthèse de nanoparticules de Cu-Sb-S ont été menés. Des nanoparticules quasi-monodisperses avec des tailles inférieures à 50 nm ont été obtenues grâce à la mise au point d'un procédé basé sur la synthèse solvothermale avec surfactant, une méthode faible coût et facilement adaptable à grande échelle. / Thermoelectric devices, capitalizing on waste heat conversion, offer good prospects for the development of autonomous systems. The main challenges for technology development are to obtain flexible, environmentally friendly and low-cost thermoelectric devices with performances sufficient enough to power small electronic devices. The aim of this thesis was thus to propose a methodology for the global analysis of thermoelectric devices for ambient temperature applications. The developed methodology enables the evaluation of key parameters impact on the global system. First, a multiscale approach for thermoelectric devices modelling is developed. In this scope, three parallel levels of modeling are addressed. At the system level, a compact model is developed in order to evaluate overall system efficiency as a function of the thermal environment. At the device level, virtual prototypes of printed devices are built and their performances are evaluated via a finite-element simulation tool. Low temperature gradient has to be dealt with by appropriate architecture design. At the material level, quantum DFT is used in conjunction with semi-classical approach using Boltzmann transport theory to calculate electronic properties. Tetrahedrite and famatinite compounds are chosen due to their promising thermoelectric properties at room temperature and their relative abundance and low cost. Secondly, an experimental work has been conducted on the synthesis of sulphide nanoparticles. Quasi-monodisperse nanoparticles with a size not exceeding 50 nm have successfully been fabricated via a low cost and easily scalable surfactant assisted solvothermal technique.
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FIRE DESIGN BY ADVANCED ANALYSIS OF ARCHETYPE STEEL-COMPOSITE STRUCTURENimisha Dilip Jain (19200691) 26 July 2024 (has links)
<p dir="ltr">Fire is an extreme event that can lead to failure of structural components and potentially collapse of the structural system or sub-systems. Currently, there are no comprehensive, research-based methodologies for performance-based fire structural design (PBFSD) of composite wall-to-floor connections subjected to gravity loads and realistic fire scenarios. The existing studies primarily focus on the performance of simple shear connections to steel columns, and lack approaches for structural design of floor systems and their connections to walls (wall-to-floor connections) at elevated temperatures. This study addresses the need for evaluating the performance of composite floor systems and composite wall-to-floor connections under fire loading and developing research-based approaches to conduct performance-based structural design of these systems at elevated temperatures.</p><p dir="ltr">This study aims to give a simpler design method for shear tab and single angle shear connections at elevated temperatures by specifying retention factors for steel yield strength, ultimate strength, bolt material strength, and weld metal strength at elevated temperatures. The connection limit state equations specified in AISC Specifications are modified to incorporate these factors for higher temperatures. Additionally, an archetype building is designed and one floor system is evaluated using Finite Element Analysis (FEA) to assess the robustness of the structure and its resistance to collapse using PBFSD.</p><p dir="ltr">It also discusses the application of fire protection materials for steel members to resist fire scenarios for specified durations. Various fire scenarios, including ventilation-controlled and fuel-controlled fires were evaluated to assess localized behavior at the connection points and the overall behavior of the structural compartment. The FE analyses included various fire scenarios, compartment locations (interior, edge, or middle), and fire protection scenarios (2-hour rating fire protection, or no fire protection on interior beams). The composite floor system is evaluated for a combination of these scenarios under fire and gravity loading.</p><p dir="ltr">Through this study, a comprehensive analysis of the behavior of composite floors systems and associated connections in SpeedCore Wall Systems (C-PSW/CF) under fire loading is achieved.</p>
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Změna kurzu ruské zahraniční politiky v 1. dekádě 21. století / Russia's Foreign Policy Change in the First Decade of the 21st CenturyValentová, Emilie January 2010 (has links)
The aim of the diploma thesis is to identify Russia's Foreign Policy change in the first decade of the 21st century. It focuses on the three most important strategic documents of the Russian Federation, the presidential decrees signed by Vladimir Putin and Dmitri Medvedev (The Foreign Policy Concepts of the Russian Federation from 2000 and 2008, The National Security Concept of the Russian Federation from 2000, The National Security Strategy of the Russian Federation from 2009 and The Military Doctrines from 2000 and 2010). Through Discourse analysis it concludes that Russia has moved to strenghtening norms of international law and multilateral cooperation between the years 2000 and 2010, it no longer uses confrontational expressions and prefers a multi-vector foreign policy accenting the Asian vector. Russia also proves to be more self-confident and ambitious. We expect a more active role in the world affairs from Russia in the second decade of the 21st century.
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BEHAVIOR AND DESIGN OF FLOOR TO SPEEDCORE WALL CONNECTIONS UNDER FIRE LOADINGMuhannad Riyadh Alasiri (17086912) 10 October 2023 (has links)
<p dir="ltr">Composite Plate Shear Wall/ Concrete Filled (C-PSW/CF), also referred to as SpeedCore walls, are being used as innovative shear wall commercial high-rise buildings. These walls offer advantages such as modularity and construction schedule contraction. The cross-section of C- PSWs/CF consists of concrete infill sandwiched between the steel faceplates, where the steel plates are tied together by steel tie bars. Elevated temperatures will result in a deterioration in the mechanical properties of steel and concrete during a fire event in buildings. Such degradation can lead to stability-related failure of structural components. Composite floors are connected to these walls through simple shear connections. The floor-to-wall connections will be exposed to elevated temperatures, which may result in connection failure and progressive collapse of structures.</p><p dir="ltr">Designing SpeedCore walls without fire protection raises concerns regarding the performance of other structural components connected to SpeedCore walls under fire loading including composite floor systems and wall-to-floor connections. Numerical studies conducted on the connections and the floor systems indicated that these structural components undergo thermal compression forces during heating and tensile forces during the cooling phases of a fire event. The goal of this research was to develop an approach for performance-based fire resistance design of complete floor systems consisting of SpeedCore walls, composite floor slabs, and wall-to-floor connections.</p><p dir="ltr">This research includes experimental and numerical analyses to gain insight into the behavior of the floor-to-SpeedCore wall connections under fire and gravity loading. The specimens included steel beams connected to SpeedCore walls through simple shear connections. Three types of floor-to-wall connections were tested including connections with through-plate, reinforcing plate, and unreinforced plate. The parameters considered in the test matrix included: connection type, temperature, loading angle, and loading direction. These parameters in the test matrix were based on results obtained from previous numerical and experimental studies in the literature. The experimental results can fill the existing knowledge gap on floor-to-wall connections for steel-concrete composite members, develop design recommendations, and benchmark numerical models.</p><p dir="ltr">Numerical models were developed to simulate the behavior of the connections (member level) and whole structures (structure level) at ambient and elevated temperatures. Finite Element (FE) analysis and Component-based Models (CB) were utilized to develop the numerical models. The developed models were benchmarked by comparing the obtained numerical results with experimental data reported in the literature. FE models have been validated at two different levels, namely member level, and system level. The performance of the designed connection for the archetype structures was studied using benchmarked FE and CB models. The behavior of various wall-to-floor connections with different steel plate (C-PSW/CF) detailing was investigated.</p><p dir="ltr">Benchmarked numerical models were used to perform a parametric study to evaluate the performance of these connections. UP connection detail was used to perform the study due to its promising experimental performance, which does not need any special detail or plate reinforcement. The study was performed by evaluating the effects of critical parameters on the connection behavior namely, bolt size, target temperature, loading angles, and loading direction</p>
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Disruptive Transformations in Health Care: Technological Innovation and the Acute Care General HospitalLucas, D. Pulane 24 April 2013 (has links)
Advances in medical technology have altered the need for certain types of surgery to be performed in traditional inpatient hospital settings. Less invasive surgical procedures allow a growing number of medical treatments to take place on an outpatient basis. Hospitals face growing competition from ambulatory surgery centers (ASCs). The competitive threats posed by ASCs are important, given that inpatient surgery has been the cornerstone of hospital services for over a century. Additional research is needed to understand how surgical volume shifts between and within acute care general hospitals (ACGHs) and ASCs. This study investigates how medical technology within the hospital industry is changing medical services delivery. The main purposes of this study are to (1) test Clayton M. Christensen’s theory of disruptive innovation in health care, and (2) examine the effects of disruptive innovation on appendectomy, cholecystectomy, and bariatric surgery (ACBS) utilization. Disruptive innovation theory contends that advanced technology combined with innovative business models—located outside of traditional product markets or delivery systems—will produce simplified, quality products and services at lower costs with broader accessibility. Consequently, new markets will emerge, and conventional industry leaders will experience a loss of market share to “non-traditional” new entrants into the marketplace. The underlying assumption of this work is that ASCs (innovative business models) have adopted laparoscopy (innovative technology) and their unification has initiated disruptive innovation within the hospital industry. The disruptive effects have spawned shifts in surgical volumes from open to laparoscopic procedures, from inpatient to ambulatory settings, and from hospitals to ASCs. The research hypothesizes that: (1) there will be larger increases in the percentage of laparoscopic ACBS performed than open ACBS procedures; (2) ambulatory ACBS will experience larger percent increases than inpatient ACBS procedures; and (3) ASCs will experience larger percent increases than ACGHs. The study tracks the utilization of open, laparoscopic, inpatient and ambulatory ACBS. The research questions that guide the inquiry are: 1. How has ACBS utilization changed over this time? 2. Do ACGHs and ASCs differ in the utilization of ACBS? 3. How do states differ in the utilization of ACBS? 4. Do study findings support disruptive innovation theory in the hospital industry? The quantitative study employs a panel design using hospital discharge data from 2004 and 2009. The unit of analysis is the facility. The sampling frame is comprised of ACGHs and ASCs in Florida and Wisconsin. The study employs exploratory and confirmatory data analysis. This work finds that disruptive innovation theory is an effective model for assessing the hospital industry. The model provides a useful framework for analyzing the interplay between ACGHs and ASCs. While study findings did not support the stated hypotheses, the impact of government interventions into the competitive marketplace supports the claims of disruptive innovation theory. Regulations that intervened in the hospital industry facilitated interactions between ASCs and ACGHs, reducing the number of ASCs performing ACBS and altering the trajectory of ACBS volume by shifting surgeries from ASCs to ACGHs.
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