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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.
91

Influences des niveaux d’activité physique et de performance physique sur la densité minérale osseuse, la géométrie osseuse de la hanche et le score de l'os trabéculaire chez de jeunes hommes en surpoids et obèses / Influences of physical activity and physical performance levels on bone mineral density, hip geometry and trabecular bone score in a group of young overweight and obese men

El Khoury, Georges 05 May 2017 (has links)
Le but cette thèse était d’explorer l’influence du niveau d’activité physique et du niveau de performance physique sur la densité minérale osseuse, la géométrie osseuse de la hanche et le score de l’os trabéculaire chez de jeunes hommes en surpoids et obèses. Trois principales études ont été menées. Une première étude a montré que la pratique d’activités physiques a un effet positif sur le CMO, la DMO et la section transversale du col fémoral chez les hommes en surcharge pondérale. Une deuxième étude a suggéré que le niveau d’activité physique influence positivement les paramètres osseux chez les hommes en surpoids et obèses et que l’optimisation de la masse maigre, de la VO2 max (L/min) et de la force maximale des membres inférieurs peut aider à prévenir l’ostéoporose chez les hommes en surpoids et obèses. Enfin, une dernière étude, a été la première à démontrer une relation positive entre la VO2 max (ml/mn/kg) et les indices de résistance osseuse du col fémoral (le CSI, le BSI et l’ISI) chez les jeunes hommes en surpoids et obèses et a donc suggéré que l’augmentation de la VO2 max chez les hommes en surpoids et obèses pourrait aider à réduire les fractures stéoporotiques. Ces différents résultats suggèrent une adaptation ostéogénique significative des jeunes hommes en surpoids et obèses en réponse à l’entrainement physique. / The aim of this thesis was to explore the influence of physical activity level and physical performance on bone mineral density, hip geometry and trabecular bone score in young overweight and obese men. Three main studies have been conducted. The first study has shown that physical activity practice has a positive effect on BMC, BMD and femoral neck crosssectional area in overweight men. The second study has shown that physical activity level positively affects bone variables in overweight/obese men and that increasing lean mass, VO2 max (L/min) and muscular strength of the lower limbs can help to prevent osteoporosis in overweight and obese men. Finally, the last study, was the first to show positive associations between maximal oxygen consumption (milliliter per minute per kilogram) and composite indices of FN strength (CSI, BSI and ISI) in young overweight and obese men and therefore suggested that enhancing VO2 max in overweight and obese men may help to reduce osteoporotic fractures. These different results suggest a significant osteogenic adaptation in young overweight and obese men in response to physical training.
92

Dispositivos emisores de luz para transmisión óptica de alta velocidad

Larrea Luzuriaga, Roberto Alejandro 04 January 2019 (has links)
La fotónica de silicio es una de las tecnologías con más auge en las últimas dos décadas. Es por ello que el estudio y desarrollo de circuitos integrados fotónicos ha tenido una importante presencia en la investigación de nuevos componentes y dispositivos para la mejora de prestaciones en sistemas de comunicaciones ópticos. Una de las principales ventajas de la fotónica de silicio es su compatibilidad con la tecnología electrónica CMOS, la cual la convierte en una plataforma prometedora para la fabricación en masa a bajo coste. El tamaño reducido de las estructuras fotónicas y las bajas pérdidas alcanzadas en guías de onda nanométricas ha permitido el desarrollo de dispositivos con una alta densidad de integración. De igual manera, se han demostrado moduladores ópticos de alta velocidad y fotodetectores altamente eficientes. Sin embargo, el desarrollo de la fuente de luz o láser, elemento indispensable en cualquier sistema de comunicaciones óptico, no es posible debido al "bandgap" indirecto del silicio. Por lo cual, otros materiales de "bandgap" directo se han estudiado y propuesto para conseguir integrar un láser sobre el chip de silicio con emisión en las bandas O y C. El principal desafío radica en alcanzar el régimen de emisión estimulada coherente por medio de un bombeo eléctrico y de forma eficiente. Para ello se han propuesto varios esquemas de integración. La integración monolítica aborda la fabricación del láser directamente en el chip. Por otra parte, la integración híbrida consiste en la fabricación del láser por separado para luego ser integrado en el chip, siendo este esquema con el que mejores resultados se han conseguido. De esta manera, el principal objetivo de la tesis ha sido el desarrollo de un láser de cavidad externa por medio de un esquema de integración híbrida y con funcionamiento en la banda O. Los distintos bloques básicos se han analizado, diseñado, fabricado y demostrado experimentalmente. Finalmente, se ha llevado a cabo la integración con el medio de ganancia demostrándose satisfactoriamente emisión estimulada y funcionamiento monomodo. Además, en la tesis se ha abordado también el acoplamiento a estructuras de guiado tipo ranura, las cuales han sido propuestas en esquemas de integración monolítica. / La fotònica de silici és una de les tecnologies amb més auge en les últimes dues dècades. És per això que l'estudi i desenvolupament de circuits integrats fotònics ha tingut una important presència a la investigació de nous components i dispositius per a la millora de prestacions en sistemes de comunicacions òptics. Una de les principals avantatges de la fotònica de silici és la seva compatibilitat amb la tecnologia electrònica CMOS, la qual la converteix en una plataforma prometedora per a la fabricació en massa a baix cost. La mida reduïda de les estructures fotòniques i les baixes pèrdues assolides en guies d'ona nanomètriques ha permès el desenvolupament de dispositius amb una alta densitat d'integració. De la mateixa manera, s'han demostrat moduladors òptics d'alta velocitat i fotodetectors altament eficients. No obstant això, el desenvolupament de la font de llum o làser, element indispensable en qualsevol sistema de comunicacions òptic, no és possible a causa del "bandgap" indirecte del silici. Per la qual cosa, altres materials de "bandgap" directe s'han estudiat i proposat per aconseguir integrar un làser sobre el xip de silici amb emissió en les bandes O i C. El principal desafiament rau a aconseguir el règim d'emissió estimulada coherent per mitjà de un bombament elèctric i de forma eficient. Per a això s'han proposat diversos esquemes d'integració. La integració monolítica aborda la fabricació del làser directament en el xip. D'altra banda, la integració híbrida consisteix en la fabricació del làser per separat per després ser integrat en el xip, sent aquest esquema amb el que millors resultats s'han aconseguit. D'aquesta manera, el principal objectiu de la tesi ha sigut el desenvolupament d'un làser de cavitat externa per mitjà d'un esquema d'integració híbrida i amb funcionament a la banda O. Els diferents blocs bàsics s'han analitzat, dissenyat, fabricat i demostrat experimentalment. Finalment, s'ha dut a terme la integració amb el medi de guany demostrant satisfactòriament emissió estimulada i funcionament monomode. A més, en la tesi s'ha abordat també l'acoblament a estructures de guiatge tipus ranura, les quals han estat proposades en esquemes d'integració monolítica. / Silicon photonics is one of the technologies that has raised a higher interest during the last two decades. Therefore, the development of photonic integrated circuits has had an important presence in the research of new components and devices for the improvement of performance in optical communication systems. One of the main advantages of silicon photonics is its compatibility with CMOS electronic technology, which makes it a promising platform for mass production at low cost. The reduced size of photonic structures and the low propagation losses achieved in nanometric photonic waveguides has allowed the development of devices with a high density of integration. Similarly, high-speed optical modulators and highly efficient photodetectors have been demonstrated. However, the development of the light source or laser, an indispensable element in any optical communication system, is not possible due to the indirect bandgap of silicon. Therefore, other direct bandgap materials have been studied and proposed to integrate a laser on the silicon chip with emission in the O and C bands. The main challenge lies in reaching the coherent stimulated emission regime by means of an electric pump and in an efficient way. For this, several integration schemes have been proposed. Monolithic integration deals with the fabrication of the laser directly on the chip. On the other hand, hybrid integration consists in the fabrication of the laser separately to later be integrated into the chip. The best results have been achieved by means of this approach. Therefore, the main goal of the thesis has been the development of an external cavity laser by means of a hybrid integration scheme and with operation in the O-band. The different basic building blocks have been analyzed, designed, fabricated and experimentally demonstrated. Finally, the integration with the active material has been carried out, successfully demonstrating stimulated emission and single-mode operation. In addition, the thesis has also addressed the coupling to slow waveguide guidance structures, which have been proposed in monolithic integration schemes. / Larrea Luzuriaga, RA. (2018). Dispositivos emisores de luz para transmisión óptica de alta velocidad [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/114827 / TESIS
93

A Homegrown DSMC-PIC Model for Electric Propulsion

Lunde, Dominic Charles 01 June 2019 (has links)
Powering spacecraft with electric propulsion is becoming more common, especially in CubeSat-class satellites. On account of the risk of spacecraft interactions, it is important to have robust analysis and modeling tools of electric propulsion engines, particularly of the plasma plume. The Navier-Stokes equations used in classic continuum computational fluid dynamics do not apply to the rarefied plasma, and therefore another method must be used to model the flow. A good solution is to use the DSMC method, which uses a combination of particle modeling and statistical methods for modeling the simulated molecules. A DSMC simulation known as SINATRA has been developed with the goal to model electric propulsion plumes. SINATRA uses an octree mesh, is written in C++, and is designed to be expanded by further research. SINATRA has been initially validated through several tests and comparisons to theoretical data and other DSMC models. This thesis examines expanding the functionality of SINATRA to simulate charged particles and make SINATRA a DSMC-PIC hybrid. The electric potential is calculated through a 7-point 3D stencil on the mesh nodes and solved with a Gauss-Seidel solver. It is validated through test cases of charged particles to demonstrate the accuracy and capabilities of the model. An ambipolar diffusion test case is compared to a neutral diffusion case and the electric field is shown to stabilize the diffusion rate. A steady state flow test case shows the simulation is able to stabilize and solve the electric potential for a plume-like scenario. It includes additional features to simplify further research including a comprehensive user manual, industry-standard version control, text file inputs, GUI control, and simple parallelism of the simulation. Compilation and execution are standardized to be simple and platform independent to allow longevity of the code base. Finally, the execution bottlenecks of linking particles to cells and particle moving were removed to reduce the simulation time by 95%.
94

Návrh a realizace systému pro maskování výpadku dispečerského PC zálohováním dat získaných z váhy TAMRON / Design and Realization of a System for Masking Dispatcher PC Cut-Off by Backing-Up Data Obtained from TAMRON Weighing-Machine

Štulír, Vojtěch January 2010 (has links)
In the productive operation any kind of plant is undesirable due to failure of system that all production has been stopped. Therefore, different security and backup devices that covered those failures are being developed and used.   This thesis describes vulnerabilities in the real operation which are important for treatment and reduce the risk of failure in the whole production. Here is analyzed problem dispatching computer failure and its solution using a module for covering failure. The function of module consists in backup during failure, their sending and treating them after system failure removal.  Gradually described, there is an analysis of the system and place the module into their architecture. After all details follow description of module development from design through implementation to deployment and testing in reality.
95

Víceúčelové měřicí zařízení / Multipurpose measuring device

David, Jan January 2016 (has links)
This thesis describes the design of portable multi-purpose measuring device with Microcontrollers from Microchip running on battery power, for displaying the measured signal uses a graphical LCD with a resolution of 240x128. The device is equipped with an oscilloscope and multimeter with auto range.
96

Rozšíření laboratorního výukového kitu PIC Edu Kit o sadu bezdrátových senzorů / Extending the Laboratory Educational Kit PIC Edu Kit with a Set of Wireless Sensors

Hanuš, Tomáš January 2016 (has links)
This thesis describes the design and implementation of extension of laboratory training model PIC Edu Kit. It is about set of wireless sensors. These sonsors have to measure temperature and deformation. Mesure of temperature was realized by temperature resistive sensor Pt100 and deformation by resistive tenzometr. These wireless moduls comunication on protocol Wi-Fi. In this work is introduced propose of measuring dictucts for measure of temperautre and deformation. There is evidenced their realization, showed software for receiving dates on PC and programme for the microcontroler.
97

”Läs uppgiften, lös den i huvudet och sen skriver du svaret” : Upplevda problem med att använda digitala läromedel vid arbete med problemlösning i ämnet matematik / ”Read the task, solve it in your head and then write down the answer” : Problems experienced when using digital teaching materials in conjunction with problem solving in mathematics

Norén, Sanna, Almgren, Rebecka January 2022 (has links)
Vi lever idag i ett samhälle där digitala verktyg är en del av barn och ungdomars vardag. Teknikens utveckling har idag resulterat i ett flertal möjligheter för skolor att integrera digitala läromedel i matematikundervisningen för att på så sätt effektivisera elevernas lärande. I ämnet matematik och specifikt i problemlösningsundervisning har det rapporterats av lärare att användningen av digitala läromedel är förhållandevis låg.  Denna studie syftade till att undersöka huruvida det problemlösningsmaterial som erbjuds genom digitala läromedel, möter det som lärarna efterfrågar till sin matematikundervisning i årskurs 1–3. Vidare undersöktes på vilket sätt digitala läromedel används i problemlösningsundervisningen samt hur lärare upplever att de digitala läromedlen påverkar elevers lärande. Studiens syfte har därmed besvarats genom kvalitativa intervjuer med verksamma lärare i årskurs 1–3 vilket därefter har analyserats och diskuterats med hjälp av ett teoretiskt ramverk.  Utifrån ramverket PIC-RAT påvisade resultaten hur lärare använder de digitala läromedlen delvis på ett förstärkande sätt, då de oftast används som variation i undervisningen samt vid genomgångar och mängdträning i form av lärospel. De digitala läromedlen används även interaktivt då eleverna endast interagerar med det digitala verktyget. Genom det interaktiva arbetet med det digitala blir eleverna således passiva med sina klasskompisar, något som lärarna i denna studie misstycker. Resultatet av denna studie påvisade att det problemlösningsmaterial som förekommer i de digitala läromedlen, inte möter det som respondenterna önskar. Lärarna anser därmed att innehållet bör utvecklas så att en mer kreativ undervisning kan utföras. / Today we live in a society where digital tools are a part of children’s and young people’s everyday life. The current development of technology has provided opportunities for schools to integrate digital teaching materials into mathematics teaching in order to make learning more efficient. In mathematics, particularly with problem solving, teachers have reported infrequent use of digital aids.   This study aimed to examine whether the problem solving material offered through digital teaching aids, meets teachers’ needs for their mathematics teaching in grades 1–3. Furthermore, this study also investigated how digital teaching aids are used in problem solving teaching as well as how teachers think digital teaching materials affect student learning.  Based on the framework PIC-RAT, the results showed how teachers use digital teaching aids in a reinforcing way, as they are most often used as variation in teaching in reviews and practicing basic skills through educational games. The digital teaching aids are also used interactively, as students only interact with the digital tools. However, the students become passive with their classmates when working interactively with digital tools, which teachers in this study disapprove of. The results of this study showed that the problem solving material that appears in the digital teaching materials does not live up to the respondent’s needs. The teachers thus believe that the content should be developed to support more creative teaching methods.
98

The β Pictoris Phenomenon Among Herbig Ae/Be Stars. UV and Optical High Dispersion Spectra

Grady, C. A. 01 January 1996 (has links)
We present a. survey of high dispersion UV and optical spectra of Herbig Ae/Be (HAeBe) and related stars. We find accreting, circumstellar gas over the velocity range +100 to +400 km s-1, and absorption profiles similar to those seen toward β Pic, in 36% of the 33 HAeBe stars with IUE data as well as in 3 non-emission B stars. We also find evidence of accretion in 7 HAeBe stars with optical data only. Line profile variability appears ubiquitous. As a group, the stars with accreting gas signatures have higher ν sin i than the stars with outflowing material, and tend to exhibit large amplitude (≥ 1m) optical light variations. All of the program stars with polarimetric variations that are anti-correlated with the optical light, previously interpreted as the signature of a dust disk viewed close to equator-on, also show spectral signatures of accreting gas. These data imply that accretion activity in HAeBe stars is preferentially observed when the line of sight transits the circumstellar dust disk. Our data imply that the spectroscopic signatures of accreting circumstellar material seen in β Pic are not unique to that object, but instead are consistent with interpretation of β Pic as a comparatively young A star with its associated circumstellar disk.
99

Fundamental Properties of Thermo-Responsive Entirely Ionic PIC (Polyion Complex) Micelles / 温度応答性を有する全イオン性PIC (ポリイオンコンプレックス)ミセルの基礎物性

Kim, Dongwook 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第23222号 / 工博第4866号 / 新制||工||1759(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 秋吉 一成, 教授 大内 誠, 准教授 松岡 秀樹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
100

Study on Propulsive Characteristics of Magnetic Sail and Magneto Plasma Sail by Plasma Particle Simulations / 粒子シミュレーションによる磁気セイル・磁気プラズマセイルの推力特性に関する研究

Ashida, Yasumasa 23 January 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第17984号 / 工博第3813号 / 新制||工||1584(附属図書館) / 80828 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 山川 宏, 教授 松尾 哲司, 准教授 中村 武恒 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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