Dissertations / Theses: 'DEMC'

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Bagnara, Maurizio. "Modelling biogeochemical cycles in forest ecosystems: a Bayesian approach." Doctoral thesis, country:IT, 2015. http://hdl.handle.net/10449/25094.

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Forest models are tools for explaining and predicting the dynamics of forest ecosystems. They simulate forest behavior by integrating information on the underlying processes in trees, soil and atmosphere. Bayesian calibration is the application of probability theory to parameter estimation. It is a method, applicable to all models, that quantifies output uncertainty and identifies key parameters and variables. This study aims at testing the Bayesian procedure for calibration to different types of forest models, to evaluate their performances and the uncertainties associated with them. In particular,we aimed at 1) applying a Bayesian framework to calibrate forest models and test their performances in different biomes and different environmental conditions, 2) identifying and solve structure-related issues in simple models, and 3) identifying the advantages of additional information made available when calibrating forest models with a Bayesian approach. We applied the Bayesian framework to calibrate the Prelued model on eight Italian eddy-covariance sites in Chapter 2. The ability of Prelued to reproduce the estimated Gross Primary Productivity (GPP) was tested over contrasting natural vegetation types that represented a wide range of climatic and environmental conditions. The issues related to Prelued's multiplicative structure were the main topic of Chapter 3: several different MCMC-based procedures were applied within a Bayesian framework to calibrate the model, and their performances were compared. A more complex model was applied in Chapter 4, focusing on the application of the physiology-based model HYDRALL to the forest ecosystem of Lavarone (IT) to evaluate the importance of additional information in the calibration procedure and their impact on model performances, model uncertainties, and parameter estimation. Overall, the Bayesian technique proved to be an excellent and versatile tool to successfully calibrate forest models of different structure and complexity, on different kind and number of variables and with a different number of parameters involved

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Srivastava, Anurag. "Comparison of Two Algorithms for Removing Depressions and Delineating Flow Networks From Grid Digital Elevation Models." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/34268.

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Digital elevation models (DEMs) and their derivatives such as slope, flow direction and flow accumulation maps, are used frequently as inputs to hydrologic and nonpoint source modeling. The depressions which are frequently present in DEMs may represent the actual topography, but are often the result of errors. Creating a depression-free surface is commonly required prior to deriving flow direction, flow accumulation, flow network, and watershed boundary maps. The objectives of this study were: 1) characterize the occurrence of depressions in 30m USGS DEMs and assess correlations to watershed topographic characteristics, and 2) compare the performance of two algorithms used to remove depressions and delineate flow networks from DEMs.

Sixty-six watersheds were selected to represent a range of topographic conditions characteristic of the Piedmont and Mountain and Valley regions of Virginia. Analysis was based on USGS 30m DEMs with elevations in integer meters. With few exceptions watersheds fell on single 7.5minute USGS quadrangle sheets, ranged in size from 450 to 3000 hectares, and had average slopes ranging from 3 to 20 percent. ArcView (3.1) with the Spatial Analyst (1.1) extension was used to summarize characteristics of each watershed including slope, elevation range, elevation standard deviation, curvature, channel slope, and drainage density. TOPAZ (ver 1.2) and ArcView were each used to generate a depression-free surface, flow network and watershed area. Characteristics of the areas 'cut' and 'filled' by the algorithms were compared to topographic characteristics of the watersheds. Blue line streams were digitized from scanned USGS 7.5minute topographic maps (DRGs) then rasterized at 30 m for analysis of distance from the derived flow networks.

The removal of depressions resulted in changes in elevation values in 0 - 11% of the cells in the watersheds. The percentage of area changed was higher in flatter watersheds. Changed elevation cells resulted in changes in two to three times as many cells in derivative flow direction, flow accumulation and slope grids. Mean fill depth by watershed ranged from 0 to 10 m, with maximum fill depths up to 40 m. In comparison with ArcView, TOPAZ, on average affected 30% fewer cells with less change in elevation. The significance of the difference between ArcView and TOPAZ decreased as watershed slope increased. A spatial assessment of the modified elevation and slope cells showed that depressions in the DEMs occur predominantly on or along the flow network. Flow networks derived by ArcView and TOPAZ were not significantly different from blue line streams digitized from the USGS quadrangles as indicated by a paired t test. Watershed area delineated by ArcView and TOPAZ was different for almost all watersheds, but was generally within 1%.

Conclusions from this study are: 1) The depressions in 30 m DEMs can make up a significant portion of the area especially for flatter watersheds; 2) The TOPAZ algorithm performed better than ArcView in minimizing the area modified in the process of creating a depressionless surface, particularly in flatter topography; 3) Areas affected by removing depressions are predominantly adjacent to the stream network; 4) For every elevation cell changed, slopes are changed for two to three cells, on average; and 5) ArcView and TOPAZ derived flow networks closely matched the blue line streams.
Master of Science

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Wöll, Alexander. "Jakub Deml : Leben und Werk (1878-1961) : eine Studie zur mitteleuropäischen Literatur /." Köln : Böhlau, 2006. http://catalogue.bnf.fr/ark:/12148/cb411428140.

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Pasqualeti, Aniélli Martini. "Investigação da atividade de eletrocatalisadores nanoestruturados para a eletrooxidação de íons BH4- em eletrólito alcalino." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/75/75134/tde-23042013-111531/.

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As células a combustível de borohidreto direto apresentam uma alta voltagem teórica (1,64 V) e alto número de elétrons por íon do combustível. Além disso, a utilização de eletrólitos alcalinos abre a possibilidade do uso de metais eletrocatalisadores não nobres e, por conseqüência, economicamente viáveis para aplicação prática. Entretanto, a falta de um eletrocatalisador altamente eficiente para a reação de oxidação de borohidreto limita o desempenho desses dispositivos, pois a oxidação total do borohidreto, envolvendo 8 elétrons por espécie BH4-, compete com vias paralelas de reação, com menor número de elétrons trocados por cada ânion BH4-. Recentemente, simulações e cálculos teóricos foram feitos para determinar os passos elementares da cinética da reação e, também, para guiar a confecção de eletrocatalisadores metálicos para a oxidação de borohidreto. Baseado nos resultados dos estudos teóricos, este trabalho teve como objetivo a investigação da eletrocatálise desta reação em nanopartículas, suportadas sobre pó de carbono, de metais puros, Au/C, Ag/C, Pt/C e Pd/C e em nanopartículas bimetálicas, formadas pela combinação entre estes metais. Os eletrocatalisadores foram sintetizados por métodos de redução química e/ou de impregnação e foram caracterizados por Difratometria de Raios X, Microscopia Eletrônica de Transmissão de Alta Resolução e Espectroscopia de Energia Dispersiva de Raios X. As atividades eletrocatalíticas foram medidas através de curvas de polarização usando eletrodo de disco rotatório. A hidrólise, com a consequente formação de H2, foi monitorada em função do potencial do eletrodo por meio de medidas de espectrometria de massas eletroquímica diferencial on-line. Os experimentos eletroquímicos, para os eletrocatalisadores de metais puros, mostraram maior atividade para Pd/C, o que foi atribuído à usa alta atividade para a eletro-oxidação do intermediário BH3OH-. O estudo do efeito da concentração de BH4-, de BH3OH- mostrou que os potenciais de onset tenderam a menores valores com o aumento da concentração, indicando que as correntes Faradaicas de eletro-oxidação direta do borohidreto e de hidroxiborano foram muito maiores que as correntes de oxidação e de desprendimento de H2. O aumento da carga de Pd/C no eletrodo levou a um aumento da corrente global de reação em baixos potenciais, o que se traduz em um efeito do aumento de área total. Dentre os materiais bimetálicos investigados, a combinação entre Pt2Pd/C apresentou a maior corrente Faradaica. O material de AgPd/C apresentou o menor potencial de onset de reação. Apesar dos resultados teóricos indicarem o aumento da atividade do Pd/C com a inserção de Ag, os resultados eletroquímicos e de espectrometria de massas indicaram maior atividade para o Pd/C puro e baixo efeito sinérgico entre os átomos de Ag e Pd. Isso foi associado ao baixo grau de interação entre os átomos de Ag e Pd nas composições atômicas investigadas.
The direct borohydride fuel cells (DBFC) display a high theoretical cell voltage (1.64) and a high electron number per borohydride ion. Furthermore, the DBFC also presents the advantages of alkaline fuel cells, in which it is possible to use non-noble metal electrocatalysts and, hence, it is economically feasible for practical applications. However the lack of highly efficient electrocatalysts for the borohydride oxidation reaction (BOR) limits the performance of these devices, since its total oxidation, involving the transfer of eight electrons per BH4- ion, competes with parallel reaction pathways with a lower number of exchanged electrons. Recently, theoretical calculations were applied to determine the elementary steps of the reaction kinetics and also to guide metallic electrocatalyst design for borohydride oxidation. Based on the theoretical results, this work aimed at the BOR electrocatalysis investigation on carbon supported nanoparticles, of pure metals, Au/C, Ag/C, Pt/C and Pd/C, and on bimetallic nanoparticles, composed by the combination of these metals. The electrocatalysts were synthesized by chemical and/or impregnation reduction methods, and X-Ray Diffraction, High Resolution Transmission Electron Microscopy and X-Ray Energy Dispersive Spectroscopy techniques were used for their physical characterization. The electrocatalytic activities were studied by steady state polarization curves using rotating disc electrodes. The borohydride hydrolysis, with the production of H2, was monitored in function of the electrode potential by on-line differential electrochemical mass spectrometry. The electrochemical experiments for the pure metal electrocatalysts showed higher electrocatalytic activity for Pd/C, and this was attributed to its high activity for BH3OH- electro-oxidation. The study of BH4- and BH3OH- concentration effect showed that with the increase of concentration, the onset potential shifted to lower values, indicating that the Faradaic currents of borohydride and hydroxyborane electro-oxidation were much higher than the current for the H2 evolution. The increase in the Pd/C load on the electrode led to an increase of the global current reaction at low potentials, which was associated to an increase in total surface area. Among the investigated bimetallic materials, the Pt2Pd/C electrocatalyst presented the higher Faradaic current. The Ag2Pd/C material showed the lower reaction potential onset. Although theoretical calculations pointed out to an increased activity of the Ag-modified Pd/C electrocatalysts in relation to that of pure Pd/C, the electrochemical and mass spectrometry results of this work indicated higher activity for pure Pd/C, and low synergic effect between the Ag and Pd atoms. This was associated to the low degree of interaction between Ag and Pd for the present investigated atomic composition.

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Junior, Flávio Colmati. "Estudo de catalisadores de Pt-Sn para o ânodo da célula a combustível de membrana trocadora de prótons alimentada com etanol direto." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-27032008-084800/.

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Eletrocatalisadores de Pt-Sn suportados em carbono de elevada área superficial foram preparados por redução química de precursores metálicosm em solução usando como agente redutor o ácido fórmico. Esse método mostrou-se muito eficiente sendo possível obter tanto catalisadores com baixos teores de Sn (razão atômica Pt:Sn de 9:1) como com altos teores de Sn (razão atômica Pt:Sn de 1:3). Entretanto, apesar de ser o Sn reduzido e ancorado sobre o substrato de carbono apenas parte deste Sn é inserido na rede cristalina da Pt sendo necessário um tratamento térmico em atmosfera redutora para aumentar o grau de liga. Foram realizados tratamentos térmicos entre 100 e 500 ºC e o melhor desempenho na célula a combustível foi obtido com o material Pt3Sn tratado a 200 ºC. O tratamento térmico a 200ºC permitiu um incremento no grau de liga dos metais Pt e Sn sem modificar a estrutura cúbica de face centrada da Pt e sem promover a coalescência das nanopartículas ancoradas no suporte de carbono. Os materiais de Pt-Sn foram caracterizados através de difração de raios-X, absorção de raios-X e microscopia eletrônica de transmissão. A atividade para a eletro-oxidação de etanol foi avaliada através de técnicas eletroquímicas e experimentos em células a combustível unitárias. Para complementar o estudo da eletro-oxidação de etanol foram realizados estudos fundamentais usando monocristais de Pt com baixos e altos índices de Miller.
Carbon supported Pt-Sn catalysts were prepared by reduction of Pt and Sn precursors with formic acid. The method allowed the efficient preparation of catalysts with low Sn contents (Pt:Sn ratio 9:1) and with high Sn contents (Pt:Sn ratio 1:3. In spite of the fact that Sn was anchored in the material, only part of the Sn is inserted in the fcc structure of Pt. Therefore, a thermal treatment in a reducing atmosphere was necessary to increase the degree of alloy. Thermal treatments were done between 100 and 500 oC and the Pt3Sn material treated at 200 oC showed the best performance in a direct ethanol fuel cell. The thermal treatment at 200 oC allowed an increase of the degree of alloy without modifying the face centered cubic Pt structure and without promoting the coalescence of the nanoparticles anchored on the carbon support. The Pt-Sn catalysts were characterized by X-ray diffraction, X-ray absorption and transmission electron microscopy. The activity for the electro-oxidation of ethanol was evaluated with electrochemical techniques and experiments in a single direct ethanol fuel cell. Studies with Pt single crystals with low and high Miller indices were done to complement the study of the ethanol electro-oxidation.

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Goujon, Anne, C. Samir K, Markus Speringer, Bilal Barakat, Michaela Potancoková, Jakob Eder, Erich Striessnig, Ramon Bauer, and Wolfgang Lutz. "A harmonized dataset on global educational attainment between 1970 and 2060 - An analytical window into recent trends and future prospects in human capital development." Cambridge University Press (CUP), 2016. http://dx.doi.org/10.1017/dem.2016.10.

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We hereby present a dataset produced at the Wittgenstein Centre (WIC) containing comprehensive time series on educational attainment and mean years of schooling (MYS). The dataset is split by 5-year age groups and sex for 171 countries and covers the period between 1970 and 2010. It also contains projections of educational attainment to 2060 based on several scenarios of demographic and educational development. The dataset is constructed around collected and harmonized empirical census and survey data sets for the projection base year. The article present the principles and methodology associated with the reconstruction and the projection, and how it differs from several previous exercises. It also proposes a closer look at the diffusion of education in world regions and how the existing gaps in terms of generations, gender, and geography - hence called the 3Gs - have been evolving in the last forty years.

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Törnqvist, Martin. "Strukturerat låtskrivande : ett undersökande arbete om låtskrivande." Thesis, Kungl. Musikhögskolan, Institutionen för musik, pedagogik och samhälle, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kmh:diva-2253.

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Rodrigues, Joaquim Carlos Mendes. "Relatório de estágio no Arquivo da Faculdade de Engenharia da Universidade do Porto : tratamento arquivístico do acervo documental do Departamento de Engenharia Electrónica e de Computadores, com recurso à aplicação informática para gestão integrada de sistemas de arquivo (GISA)." Master's thesis, Universidade de Évora, 2009. http://hdl.handle.net/10174/21053.

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O presente relatório, reporta-se à descrição do estágio, cuja duração foi de 356 horas, realizado no Arquivo da Faculdade de Engenharia da Universidade do Porto. Decorreu entre os meses de Fevereiro e Agosto de 2009, sob orientação da Professora Doutora Fátima Nunes. No presente está espelhado todo o trabalho desenvolvido durante o estágio, que basicamente foi o tratamento arquivístico do acervo documental do DEEC (Departamento de Engenharia Electrotécnica e de Computadores), com recurso à aplicação informática para GISA (Gestão Integrada de Sistemas de Arquivo), passando pelas seguintes fases: Identificação / Caracterização do Objecto de Estudo; Estudo orgânico - funcional do contexto da produção da informação; Recenseamento técnico das unidades físicas; Constituição das séries; Avaliação e elaboração de uma proposta de selecção e Verificação e intervenção das condições físicas de acondicionamento. Todo o trabalho desenvolvido seguiu o objectivo inicialmente proposto no plano de estágio, permitindo assim a sua concretização. – ABSTRACT: The aim of the present report is to describe the training activity developed at the archive of Faculdade de Engenharia da Universidade do Porto all over 356 hours; the tutorial was made by Professor Fátima Nunes and it took place between February and August of 2009. The report comprises all the work developed across the training period which consists of treating the documents of DEEC (Departamento de Engenharia Electrónica e de Computadores), using an aplicational software GISA (Gestão Integrada de Sistemas de Arquivo). The work comprised several stages: Identification / Determination of the Object of Work; Organic Study – contextualised description of information production; Technical Censoring of the physical units; Series Construction. Creation and Evaluation of the selection criteria; Validation and intervention on the logistics. The work was targeted to meet the defined standards on the training plan consequently allowing for a clear measurement of its achievements.

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Dias, Ricardo Rodrigues. "Preparação e caracterização de eletrocatalisadores PtRu, PtSn, PtRh, PtRuRh e PtSnRh para oxidação direta de álcoois em células a combustível tipo PEM utilizando a metodologia da redução por álcool." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-08092009-172849/.

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Os eletrocatalisadores PtRh/C, PtRu/C, PtSn/C, PtRuRh/C e PtSnRh/C (20% em massa de metais) foram preparados pelo método da redução por álcool usando H2PtCl6.6H2O (Aldrich), RhCl3.xH2O (Aldrich) e SnCl2.2H2O (Aldrich) como fonte de metais e o carbono Vulcan XC-72 como suporte. Os eletrocatalisadores foram caracterizados pelas técnicas de EDX, difração de raios X e voltametria cíclica. A eletro-oxidação do metanol e do etanol foram estudadas através das técnicas de voltametria cíclica, cronoamperometria e curvas de polarização obtidas em células a combustível unitárias alimentadas diretamente por metanol ou etanol. As análises por EDX mostraram que as razões atômicas dos diferentes eletrocatalisadores preparados pelo método da redução do álcool são bastante similares às composições nominais de partida. Em todos os difratogramas para os eletrocatalisadores preparados observa-se um pico largo em aproximadamente 2 = 25o o qual é associado ao suporte de carbono e quatro outros picos de difração em aproximadamente 2 = 40o, 47o, 67o e 82o os quais são associados aos planos (111), (200), (220) e (311), respectivamente, da estrutura cúbica de face centrada (CFC) de platina e ligas de platina. PtSn/C e PtSnRh/C além da estrutura cúbica de face centrada apresentaram também fases de óxidos de estanho em 2 = 34o. PtSn/C e PtSnRh/C apresentaram os melhores resultados para o etanol a temperatura ambiente, enquanto que para a eletro-oxidação do metanol os sistemas PtRu/C, PtSn/C e PtRuRh/C apresentaram os melhores resultados. Os testes em células a combustível para o etanol mostraram que o sistema PtSnRh/C foi mais ativo em relação ao sistema PtSn/C. No caso do metanol PtRuRh/C apresenta um desempenho ligeiramente superior ao sistema PtRu/C e PtSn/C.
In this work, Pt/C, PtRh (90:10), PtRh/C (50:50), PtSn/C (50:50), PtRu (50:50)/C, PtRuRh/C (50:40:10) and PtSnRh/C (50:40:10) were prepared by an alcohol-reduction process with metal loading of 20 wt.% using H2PtCl6.6H2O (Aldrich), SnCl2.2H2O (Aldrich),and RhCl2.XH2O (Aldrich) as metals sources and Vulcan XC72 as support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry (CV). The electro-oxidation of ethanol was studied by CV, chronoamperomety at room temperature in acid medium and tests at 100 0C on a single cell of a direct methanol or ethanol fuel cell. The EDX analysis showed that the metal atomic ratios of the obtained electrocatalysts were similar to the nominal atomic ratios used in the preparation. The diffractograms of electrocatalysts prepared showed four peaks at approximately 2 =400, 470, 670 and 820, which are associated with the (111), (200), (220) and (311) planes, respectively, of a face cubic-centered (fcc) structure characteristic of platinum and platinum alloys. The average crystallite sizes using the Scherrer equation and the calculated values were in the range of 23 nm. For PtSn/C and PtSnRh/C two additional peaks were observed at 2 = 340 and 520 that were identified as a SnO2 phase. PtSn/C (50:50) and PtSnRh/C (50:40:10) electrocatalyst showed the best performance for ethanol oxidation at room temperature. For methanol oxidation at room temperature PtRu/C, PtSn/C and PtRuRh/C electrocatalysts showed the best performance. Tests at 100 0C on a single cell of a direct ethanol fuel cell PtSnRh/C showed the best performance, for methanol oxidation PtRuRh/C showed the best performance.

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Bring, Hedda. "A Digital Elevation Model of the Lövåsen Esker." Thesis, University of Gävle, Department of Technology and Built Environment, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-234.

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The threats imposed by the ongoing climate change become successively more clear. In the municipality of Sandviken the possible rise in water level in the lake Storsjön might cause major problems. This study aims to produce an elevation model over one of the threatened areas so that the effect of different water levels in the lake can be studied in the future.

The area of study consists of an esker cutting straight through the lake Storsjön. The area is densely populated and the size is about 13 hectares.

Measurements were performed, both with GPS, utilizing Network-RTK, and with total station. The formations of the ridge were captured by following the breaklines with a point density of 225 points/ha as an intended goal.

The GPS measurements were transformed into the local coordinate system of Sandviken municipality. The measured coordinates for six control points were compared to the true coordinates. The fit was not perfect, so a Helmert transformation was performed on the plane coordinates. The accuracy of the measurements was below 50 mm after the transformation. Net adjustments in plane and height were performed on the total station measurements. The error ellipses for the station points varied from 2 to 44 mm. The over all point density achieved was 274 points/ha.

Two elevation models were created, one Triangular Irregular Network (TIN) and one interpolated model using a kriging interpolation. Contour lines from both models were produced and compared with each other. The TIN creates a more angular surface and therefore the contour lines are not as smooth as in the interpolated model. Both models showed good resemblance compared with the original data.

Problem relaterade till klimatförändringar blir alltmer uttalade. I Sandvikens kommun kan problem uppstå om vattennivåerna i Storsjön stiger. Syftet med det här examensarbetet var att skapa en höjdmodell över ett av de utsatta områdena för att effekter av en eventuell vattennivåhöjning skall kunna studeras i framtiden.

Området består av en rullstensås som sträcker sig rakt igenom Storsjön. Området är tättbefolkat och ca 13 hektar stort.

Mätningarna utfördes med både GPS och totalstation. Vid GPS-mätningarna utnyttjades Nätverks-RTK. Åsens formationer fångades genom att följa brytlinjer med en estimerad punkttäthet på 225 punkter/ha.

GPS-mätningarna transformerades till Sandvikens lokala koordinatsystem. De mätta koordinaterna för sex kontrollpunkter jämfördes med de sanna koordinaterna. Eftersom de mätta värdena inte passade in perfekt så utfördes en Helmerttransformation av plankoordinaterna. Noggrannheten på mätta värden var inom 50 mm efter transformationen. Nätutjämningar i plan och höjd gjordes på totalstationsmätningarna. Felellipserna för stationspunkterna varierade mellan 2 och 44 mm. Den sammanlagda punkttätheten uppgick till 274 punkter/ha.

Två höjdmodeller framställdes, en TIN-model (Triangular Irregular Network) och en interpolerad model där interpolationsmetoden kriging användes. Höjdkurvor framställda från respektive modell skapades och jämfördes med varandra. Ett TIN ger en mer kantig yta vilket återspeglas i höjdkurvorna som inte är lika jämna som de från den interpolerade modellen. Båda modellerna visade god överensstämmelse med originaldata.

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Deml, Karl-Friedrich [Verfasser], and Jens [Akademischer Betreuer] Schlossmann. "Interaktionen von Histamin H1-Rezeptoragonisten und –antagonisten mit dem humanen Histamin H4-Rezeptor / Karl-Friedrich Deml. Betreuer: Jens Schlossmann." Regensburg : Universitätsbibliothek Regensburg, 2012. http://d-nb.info/1023362104/34.

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Kattirtzi, Michael. "'Challenge and be challenged' : a history of social research capacity and influence in DEFRA and DECC, 2001-2015." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/23492.

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Government social researchers are a group of civil servants who have been overlooked in the existing literature on policy-making in the UK. Their role is particularly intriguing in policy areas relating to environment, food, and energy policy. In these domains, researchers in Science and Technology Studies have argued that policy-makers hold flawed assumptions about citizens’ views and likely actions, contributing to an image of UK policy institutions as overly technocratic and resistant to change. In this context, this thesis aims to understand changes in social research capacity and influence in the Department for Environment, Food and Rural Affairs (DEFRA) and the Department of Energy and Climate Change (DECC) between 2001 and 2015. Based on an analysis of more than 200 documents and 46 interviews with civil servants and external researchers, this thesis illuminates the growth of social research capacity and influence within DEFRA and DECC, since these departments were formed in 2001 and 2008 respectively. The first two empirical chapters (4 & 5) explain how social research capacity expanded within specific institutional, political, and epistemic contexts, through changes in how actors perceived the meanings, roles, and value of social research. It is shown that, contrary to what has been implied by recent literature, DEFRA and DECC are epistemically diverse and dynamic: they house multiple and conflicting epistemic perspectives which are reshaped over time. Moreover, social researchers are committed to performing a ‘challenge function’, whereby they question assumptions, values, and the framing of ideas. Indeed, such challenging has been important in shaping the capacity for social research within these departments. Social researchers’ ‘challenge function’ has also contributed to their gaining greater influence in DEFRA and DECC. Considering policy areas from each department in depth, Chapters 6 & 7 show that social researchers have enabled both ‘single-loop’ and ‘double-loop’ learning. As a result, in both departments social researchers have had some success in encouraging their colleagues to develop and test out policy ideas with the help of empirical research about citizens’ perspectives and everyday lives. While social researchers’ 'challenge function' is a significant policy learning mechanism, it has also been inhibited in various ways within these departments. The thesis concludes that their challenge function could be strengthened if social researchers gain greater representation in the senior civil service and more institutional recognition of their expert knowledge relating to a policy area (besides their skills). Moreover, better interdisciplinary collaboration is needed early on in policy development processes. Such changes have the potential to improve both the effectiveness and democratic legitimacy of policy-making within DEFRA and DECC.

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SILVA, F. N. A. "Representação política e seus meandros: percepções da relação entre eleitos e eleitores." Universidade Federal do Espírito Santo, 2016. http://repositorio.ufes.br/handle/10/4354.

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Análise da representação política centradanos elementos que constituem os laços conectivos entre representantes e representados. A partir dos objetivos de compreender o fenômeno político da representação e suas formas de desenvolvimento investigou-se a relação entre eleitos e eleitores e seus meandros, com o intuito de saber se a representação acontece ou se vive uma crise, na qual a responsividade de uma parte a outra não ocorre ou não se efetiva. Iniciada com abordagem teórica da representação política, são trazidas as abordagens e aferições dos autores da Política acerca do tema. Feita a apreciação teórica, a representação enquanto fenômeno político é analisada a partir do estudo de três fenômenos que ocorrem em seu bojo: as eleições, o papel dos partidos políticos e a ação dos meios de comunicação de massa. Com a compreensão desses três elementos, suas relações e influências na representação política, buscou-se diagnosticar como o fenômeno se desenvolve e se o mesmo vive um momento de crise ou de redefinição de suas formas de relação. No momento seguinte lança-se mão da pesquisa empírica e a utilização dos resultados obtidos com entrevistas realizadas com ex-representantes que pertenceram ao Poder Legislativo Estadual e membros da sociedade civil organizada capixaba, servindo os resultados obtidos de exemplo para atestar as exposições teóricas e nortear a conclusão acerca da representação no que tange a seu desenvolvimento, à caracterização de suas relações e sua efetividade. Como conclusão apresenta-se os novos caminhos que a representação política passa a traçar na atualidade, como consequência da modificação das formas de comunicação, que expõe outras alternativas além dos meios de mídia de massa, bem como o declínio do papel dos partidos políticos nas relações de intermediação entre o candidato/político e seus eleitores, e a força do capital. A compreensão que se chega do fenômeno da representação política na atualidade é de um quadro de mudanças e adequações, a partir das novas realidades que se apresentam nas relações sociais e políticas, que expõem uma ligação entre representantes e representados que se mantem. E apesar das sinuosidades que se impõem a partir da força do capital e da desigualdade social promovida pela realidade estratos dominantes e dominados, os novos caminhos da representação política apontam pelo perdurar da conexão e responsividade entre mandatários e mandantes, afastando uma ideia de crise.

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André, Damien. "Modélisation par éléments discrets des phases d’ ébauchage et de doucissage de la silice." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14501/document.

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Les composants optiques de silice traversés par des flux lasers de haut niveau d'énergie à des longueurs d'onde de 351 nm peuvent être soumis à des endommagements. Il est admis que la présence de microfissures en sous surface, induit par les procédés d'abrasion des composants optiques, joue un rôle clé dans l'initiation des dommages lasers. Cette thèse propose de simuler le procédé de surfaçage par la méthode des éléments discrets afin de caractériser la densité et la répartition des microfissures en fonction des paramètres d'usinage
When fused silica optics are submitted to high-power laser (such as megajoule laser or National Ignition Facility) at the wavelength of 351 nm, fused silica optics can exhibit damage, induced by the high amount of energy traversing the part. Current researches have shown that this damage could be initiated on pre-existing sub-surface damages created during the polishing processes. The discrete element method (DEM) is proposed to simulate the polishing process and its impact on sub-surface damage creation

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Montane, Juana Maria. "Geophysical Analysis of a Central Florida Karst Terrain using Light Detection and Ranging (LIDAR) and Ground Penetrating Radar (GPR) Derived Surfaces." FIU Digital Commons, 2001. http://digitalcommons.fiu.edu/etd/42.

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Airborne LIDAR (Light Detecting and Ranging) is a relatively new technique that rapidly and accurately measures micro-topographic features. This study compares topography derived from LIDAR with subsurface karst structures mapped in 3-dimensions with ground penetrating radar (GPR). Over 500 km of LIDAR data were collected in 1995 by the NASA ATM instrument. The LIDAR data was processed and analyzed to identify closed depressions. A GPR survey was then conducted at a 200 by 600 m site to determine if the target features are associated with buried karst structures. The GPR survey resolved two major depressions in the top of a clay rich layer at ~10m depth. These features are interpreted as buried dolines and are associated spatially with subtle (< 1m) trough-like depressions in the topography resolved from the LIDAR data. This suggests that airborne LIDAR may be a useful tool for indirectly detecting subsurface features associated with sinkhole hazard.

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Wonkovich, Mark A. "Evaluation of High-resolution Digital Elevation Models For Creating Inundation Maps." Bowling Green State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1167945221.

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Ouvrier-Buffet, Patrice. "Modifications physiologiques chez le coureur de demi-fond au cours d'une saison d'entrainement." Clermont-Ferrand 2, 1994. http://www.theses.fr/1994CLF22517.

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L'objet de ce travail est de mettre en évidence certains paramètres physiologiques dont la consommation maximale d'oxygène (vo#2max), la vitesse a 4 mmoles (v 1a4), l'économie de course (vo#2/vitesse) et la vitesse maximale aérobie (vo#2#m#a#x/cout énergétique), afin de déterminer dans une population (n = 52) de spécialistes de demi-fond (courses de 800 m au 5000 m) de niveau régional a international, quelle peut être l'influence de ces paramètres sur la réalisation de performances. En outre, une étude complémentaire sur 12 sujets (spécialistes de demi-fond, ages de 18 ans), ayant pour but d'observer des modifications de certains facteurs physiologiques au cours d'une saison d'entrainement a été effectuée. Il ressort de cette étude, que le 800 m est une épreuve a part dans le demi-fond, compte-tenu d'une participation prépondérante du métabolisme anaérobie mis en jeu lors de cette course. Les spécialistes de cette discipline possèdent des caractéristiques anthropométriques et physiologiques significativement différentes par rapport au reste de la population du demi-fond (sujets plus grands et plus lourds, avec des vo#2max plus faibles, mais plus économiques aux vitesses de course élevées). Sur l'ensemble des spécialités on observe que vo#2max représente un élément déterminant de la performance, ainsi d'ailleurs que la v 1a4 et la vma. En revanche, l'économie de course (ec) étudiée en tant que paramètre isole n'est pas associée a la performance. L'étude de vo#2 a des puissances sous-maximales a permis de mettre en évidence que celui-ci évoluait de manière curvilinéaire lorsqu'on se rapprochait des vitesses de course maximales ainsi que lorsqu'on se rapprochait des allures de marche. Enfin, l'entrainement au cours d'une saison a montre une évolution significative de vo#2max et de v 1a4 (p<0,001). En revanche, ec n'est pas modifiée. Cependant, ec combinée a vo#2max entraine une amélioration significative de la vma, paramètre hautement corrélé avec la performance a partir du 1500 m. En conclusion, ce travail confirme la prépondérance de certains paramètres physiologiques nécessaires a la réalisation de performances en demi-fond. L'entrainement de type fractionne semble le plus approprie pour développer ces facteurs déterminants

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Saha, Kakoli. "Object-Oriented classification of drumlins from Digital Elevation Models." Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1289558937.

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Rigueira, Siqueira Fábio. "Soberania em xeque?: a arbitragem internacional privada como método alternativo de resolução de disputas comerciais : um estudo político do caso brasileiro." Universidade Federal de Pernambuco, 2003. https://repositorio.ufpe.br/handle/123456789/1705.

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Julgamentos privados de conflitos comerciais entre empresas brasileiras e estrangeiras é mais uma marca da evolução das trocas comerciais entre as nações. Faz parte da constituição de uma nova ordem para o comércio mundial que vem pregando a doutrina do livre comércio entre empresas que negociam suas mercadorias em um mundo globalizado. Uma política voltada para incitar a participação privada na resolução dos conflitos comerciais, através da arbitragem comercial, deu ao governo brasileiro a oportunidade de contribuir com o esforço das pressões internas representadas pelo setor da indústria e comércio, bem como a pressão internacional da UNCITRAL, órgão da ONU (Organização das Nações Unidas). Contudo, a pesquisa notou que a soberania nacionalista brasileira ainda é o principal entrave institucional ao incremento da arbitragem comercial internacional. Mediante uma abordagem crítica registra-se o valor simbólico e conservador da soberania nacional

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Fakih, Mahmoud. "Modélisation numérique discrète de la croissance racinaire dans un sol : relation force-forme." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT323/document.

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Les racines des plantes jouent un rôle important dans la croissance et le développement des plantes, et il est bien connu que les interactions mécaniques entre une croissance racinaire et le sol environnant peuvent avoir un impact majeur sur la croissance des racines et par conséquent sur la production de biomasse végétale. Ces interactions mécaniques sont l'un des nombreux facteurs qui peuvent expliquent la variabilité de l'architecture des racines, y compris les facteurs génétiques, environnementaux et l'instabilité du développement. Mais ce facteur a souvent été sous-estimé. Nous supposons que la structure hétérogène du sol à l'échelle des grains, démontrée par la large répartition des forces, peut influencer d'une manière significative sur les trajectoires de croissance des racines. Ce travail de thèse vise à déterminer comment les grains dans les sols granulaires se réorganisent sous l'action de la croissance des racines, et en retour, comment les forces résultantes agissant sur les apex des racines modifient leur développement, y compris la cinématique de leurs trajectoires. Nous avons développé un modèle numérique 2D de la croissance des racines dans un milieu granulaire en utilisant la méthode des éléments discrets (DEM). Le modèle est capable de calculer les forces de contacts grain-grain et racine-grain dans un milieu granulaire. Le système racinaire est modélisé en utilisant des chaînes d'éléments de spheroline connectés. L'orientation de la croissance des racines, à chaque étape de croissance est déterminée par la dynamique de la racine entière sous l'action des forces élastiques internes et des forces de réaction exercées par les grains, ces sont les interactions mécaniques qui contrôlent la croissance numérique dans le modèle.Des études paramétriques ont été réalisées afin (i) d'estimer l'influence de la structure granulaire (distribution de grains de diamètre, la cohésion, la fraction volumique ...) et les propriétés mécaniques des racines (la rigidité à la flexion) sur le signal de force axiale agissant sur la pointe de la racine, et sur les trajectoires et (ii) de définir les lois physiques générales qui peuvent être utilisées en outre pour analyser des données expérimentales. Les courbes de distribution des forces axiales calculées normalisées par leurs moyens au cours d'une période donnée de la croissance, sont caractérisées par une loi de puissance décroissante pour les forces en dessous de la force moyenne, et une décroissance exponentielle pour les forces ci-dessus de la force moyenne, reflétant ainsi la large répartition des forces à l'intérieur d'un matériau granulaire. Une analyse de l'écart-type des déformations locales des trajectoires des racines, résulte deux régimes en fonction la rigidité de la racine. Une première lorsque le sol contrôle les déformations des racines, et une deuxième lorsque la racine est trop rigide, et se déplace plus les grains environnants durant la croissance
Plant roots play an important role in the growth and development of plants, and it is well known that the mechanical interactions between a growing root and the surrounding soil can have a major impact on root growth and consequently on plant biomass production. These mechanical interactions are one of numerous factors that explain the variability of root architecture, including genetics, environment and developmental instability. But this factor has often been under-estimated. I hypothesize that the heterogeneous structure of soil at the particle scale, demonstrated by the broad distribution of forces, can significantly influence root growth trajectories. This thesis aims at determining how grains in granular soils are reorganized under the action of growing roots, and in return how the resulting forces acting on root tips modify their development, including the kinematics of their trajectories, in order to develop a general biophysical law of root-soil mechanical interactions. I developed a 2D numerical model of root growth in a granular medium using a Discrete Element Model (DEM). The model is able to compute grain-grain and root-grain contact forces within a granular medium. The root system is modelled using chains of connected spheroline elements. The orientation of root growth at every growth step is determined by the dynamics of the whole root under the action of its internal elastic forces and reaction forces exerted by the grains, which are the mechanical interactions that control numerical growth in the model.Parametric studies were carried out in order to (i) estimate the influence of granular structure (grain diameter distribution, cohesion, volume fraction) and root mechanical properties (root bending stiffness) on the axial force signal acting on the root tip, and on the root trajectories and (ii) define general physical laws that can be used further to analyze experimental data. The distribution curves of computed root tip-grain forces normalized by the mean force during a given period of growth were characterized by a decreasing power law for forces below the mean force, and an exponential fall-off for forces above the mean force, thus reflecting the broad distribution of forces inside the granular material. An analysis of the standard deviation of the local deformations of root trajectories resulted in two different regimes with regard root stiffness. In the first regime, soil controlled the root deformation and in the second, the root trajectory was straighter and displaced more significantly the surrounding grains during growth

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Telò, Mario Eupolis. "Eupolidis Demi /." Firenze : Le Monnier, 2007. http://www.loc.gov/catdir/toc/casalini06/07585616.pdf.

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Singh, Nachatter. "Indian diaspora to Spain demo-spatial analysis and immigrant integration." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666821.

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Durante las últimas dos décadas, la acelerada globalización y las políticas económicas neoliberales han contribuido a facilitar el rápido movimiento de capitales y personas en todo el mundo. Migración a gran escala de personas del mundo en desarrollo (por ejemplo, India, que es el mayor proveedor de mano de obra) a los países desarrollados, la creciente contribución de la población emigrante en el desarrollo de los países de origen y renovado papel desempeñado por la población de la diáspora en la política global ha reavivado la importancia de las "diásporas" en los debates académicos y de relaciones internacionales. En la actualidad no existe una única fuente de datos que pueda proporcionar información precisa sobre todas las personas o sus descendientes que forman la población de la diáspora. En la primera parte de esta disertación, me centré en la diáspora india. En primer lugar, analicé diferentes fuentes de datos que pueden usarse para medir el tamaño de la población de la diáspora y la expansión del espacio actual de la diáspora india, que según el gobierno indio tiene más de 30 millones de personas viviendo en 208 países. En segundo lugar, he analizado la evolución de diferentes diásporas en comparación entre sí y el efecto de la globalización sobre ellas. Al centrarme en las diásporas de la India y México, he explorado, por una parte, la actitud cambiante de los países de acogida hacia su población de la diáspora, y, por otro lado, el impacto de los cambios demográficos, económicos y políticos en los países de origen en el crecimiento futuro de las comunidades de la diáspora. Y finalmente, al centrarme en la inmigración india (principalmente la comunidad sij) a España, he estudiado la creación de diferentes espacios de diáspora a través de la interrelación de los inmigrantes entre sí y su movilidad interna en los nuevos destinos de la misma. También he resaltado la transcendencia de las redes de comunicación transnacionales en la creación de espacios virtuales de la diáspora, que son muy dinámicos y consten de diferentes niveles. España es una adición reciente a la diáspora india. La inmigración de trabajadores indios al sur de Europa ha elevado su posición como un destino periférico en la diáspora india. La segunda parte de esta disertación se centra en la población inmigrante india en España, especialmente, en su perfil sociodemográfico y la distribución espacial. En esta parte, analicé el crecimiento de la comunidad india en España durante las últimas dos décadas y su nivel de concentración y segregación residencial en diferentes ciudades metropolitanas de España. También estudié la exposición de inmigrantes indios a la sociedad de acogida y su condición socioeconómica en comparación con otras comunidades de inmigrantes en España. El hecho de que el aumento exponencial de la inmigración india a España sea relativamente reciente y la ausencia de vínculos históricos y coloniales entre España y la India hace que este estudio sea más interesante ya que nos brindará la oportunidad de observar la expansión de la diáspora india a territorios vírgenes donde no comparten ningún fondo común, pero ahora están contribuyendo a la formación de una sociedad muy diversa y vecindarios heterogéneos. En la tercera parte de esta disertación, examiné el nivel de integración de los inmigrantes indios en diferentes ámbitos de la sociedad de acogida y los factores responsables de su configuración. Como la población sij representa la mayoría de la población inmigrante india en España, también abordé cómo las diferentes generaciones de inmigrantes sij en España se enfrentan al desafío de preservar su identidad y coexistencia pacífica con la sociedad de acogida.
During the last two decades, accelerated globalization and neoliberal economic policies have facilitated the rapid movement of capital and people around the world. Large-scale migration of people from the developing world (for example, India, which is the largest supplier of labour) to developed countries, the growing contribution of the migrant population in the development of countries of origin and the role played by the diaspora population in global politics has revived the importance of "diasporas" in academic debates and international relations. At present, there is no single source of data that can provide accurate information about all the people or their descendants that make up the diaspora population. In the first part of this dissertation, I focused on the Indian diaspora. First, I analysed different data sources that can be used to measure the size of the diaspora population and the expansion of the current space of the Indian Diaspora, which according to the Indian government has more than 30 million people living in 208 countries. Secondly, I studied the evolution of different diasporas in comparison to each other and the effect of globalization on them. By focusing on the diasporas of India and Mexico, on the one hand I explored the changing attitude of host countries towards their Diaspora population and on the other hand the impact of demographic, economic and political changes on the countries of origin in the future growth of the diaspora communities. And finally, by focusing on Indian immigration (mainly the Sikh community) to Spain, I have studied the creation of different diaspora spaces through the interrelation of immigrants and their internal mobility in the new destination countries. I have also highlighted the transcendence of transnational communication networks in the creation of virtual spaces of the diaspora, which are very dynamic and consist of different levels. Spain is a recent addition to the Indian diaspora. The immigration of Indian workers to southern Europe has elevated its position as a peripheral destination in the Indian diaspora. The second part of this dissertation focuses on the Indian immigrant population in Spain, especially on their sociodemographic profile and spatial distribution. In this part, I analysed the growth of the Indian community in Spain during the last two decades and its level of concentration and residential segregation in different metropolitan cities of Spain. I also studied the exposure of Indian immigrants to the host society and their socioeconomic status compared to other immigrant communities in Spain. The fact that the exponential increase of Indian immigration to Spain is relatively recent and the absence of historical and colonial ties between Spain and India makes this study more interesting as it gives us an opportunity to observe the expansion of the Indian diaspora to virgin territories where they do not share any common history, but now they are contributing to the formation of a very diverse society and heterogeneous neighbourhoods. In the third part of this dissertation, I examined the level of integration of Indian immigrants in different spheres of the host society and the factors responsible for it. As the Sikh population represents the majority of the Indian immigrant population in Spain, I also addressed how the different generations of Sikh immigrants in Spain face the challenge of preserving their identity and peaceful coexistence with the host society.

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Del, sorbo Pietro. "Modélisation multi-échelle des tissus secs : Application à l'impact." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0003/document.

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Ce travail de thèse est dédié au développement d’un modèle numérique prédictif du comportement de tissu sec soumis à l’impact à haute vitesse. La capacité d’un modèle numérique à prédire au plus juste des performances balistiques d’un tissu est étroitement liée à la bonne représentation des énergies en jeu et de la dynamique de rupture des plis. Parmi les différentes stratégies adoptées pour modéliser un tissu, les modèles mésoscopiques sont les plus populaires du fait de leur capacité à représenter fidèlement l’évolution de l’impact combinée à un coût de calcul raisonnable ; les torons sont alors traités comme des milieux continus.Pour représenter un ensemble de fibres disjointes comme un milieu continu, un modèle constitutif approprié est nécessaire. Celui généralement adopté est capable de bien représenter les propriétés longitudinales d’un toron mais limitatif pour représenter le comportement de sa section droite. Récemment, différents travaux ont démontré l’importance de la mécanique liée à la section droite d’un toron dans la rupture des tissus. Elle joue un rôle majeur pour aboutir à un modèle numérique prédictif. L’objet de cette thèse est de développer une nouvelle loi constitutive capable de surpasser les limites du modèle linéaire élastique classique tout en maintenant une bonne représentation des propriétés longitudinales du toron et un coût de calcul acceptable.La première étape a été de comprendre les phénomènes physiques et de quantifier en particulier les effets liés à la section droite du toron sur les propriétés balistiques d’un tissu. Pour répondre à cette question, deux modèles numériques à l’échelle microscopique d’un toron de Kevlar soumis à l’impact transverse ont été développés. Les résultats obtenus ont montré que la mécanique de la section droite a des répercussions sur l’initialisation de la rupture du fil mettant en jeu des énergies significatives pendant la première phase d’un impact. La nécessité de prendre en compte les aspects physiques liés à la section droite d’un toron a été finalement confirmée.A partir des résultats précédents, un nouveau modèle constitutif de toron adapté à des applications dynamiques a été développé. Une formulation hyperélastique, précédemment utilisée pour des analyses statiques a été étendue au cas de l’impact et une nouvelle approche multi-échelle a été proposée pour la détermination des paramètres matériaux. La validation de la nouvelle loi a été faite en comparant les résultats obtenus à l’échelle mésoscopique (toron) avec ceux obtenus par les analyses à la micro-échelle (fibre). L’approche proposée est capable de reproduire l’évolution de la section droite du fil pendant l’impact en gardant la bonne représentation de ses propriétés longitudinales.Par la suite, le modèle de toron proposé a été implémenté au niveau du tissu. Les résultats ont confirmé les observations faites à l’échelle du toron. Le modèle de tissu composé par des torons hyperélastiques est capable de représenter correctement la dynamique d’impact , l’évolution des énergies en jeu et la rupture du tissu. La stabilité numérique du modèle a également pu être appréciée.Finalement, le modèle mésoscopique de toron proposé permet une bonne représentation du comportement dynamique et appréhension de la rupture. Il devient ainsi un outil pratique et efficace pour la prédiction des performances balistiques de tissus
The current thesis work focused on the development of a predictive numerical model of dry fabrics under high velocity impact.A mature bibliography exists on the subject. The impact phenomenon can be essentially resumed as an energy transfer between the colliding object and the fabric layers. The correct prediction of the fabric ballistic performance by a numerical model is related to the correct representation of the fabric energy evolution and its failure dynamic. Different numerical strategies have been proposed to model a fabric under ballistic impact. Mesoscopic numerical models resulted to be the most popular since they provide a realistic representation of the phenomenon for a reasonable computational cost. This is possible thanks to the main assumption of treating yarns as continuous media.In order to represent a discrete fiber bundle as a continuum an appropriate constitutive behavior have to be formulated. The universally adopted constitutive law accurately describes yarns longitudinal properties but it is limited in the representation of their transverse mechanical behavior. Recent studies have demonstrated how this last point is intrinsically related to fabrics failure and multilayer textiles response, then its correct representation becomes a critical point for an accurate model. The goal of the current work has been to provide a new constitutive model which overcome the limitation of the classic linear elastic approach while keeping unaltered its advantages, i.e. low computational costs and accurate description of yarn longitudinal behavior.The first step of this dissertation was to quantify the yarn cross section effects over textile ballistic properties and the phenomena related to this aspect. In order to provide an answer, two microscopic numerical studies of a single Kevlar yarn transversely impacted have been presented. Results showed how yarn transverse mechanical behavior has a role in failure initialization, while its energetic contribution to the global energy balance is not negligible during the first phases of an impact. The importance of a correct representation of the yarn transverse behavior for a predictive fabric numerical model was then confirmed.Starting from the previous microscopic observations, a consistent yarn continuum model for impact applications has been proposed. An hyperelastic formulation previously developed for static applications has been extended to impact analyses and a novel multiscale approach for the determination of all the material parameters has been introduced. The validation of the hyperelastic approach has been performed comparing the results with those obtained at the microscale. Compared to the classical approach, the introduced constitutive law is actually able to reproduce the evolution of the yarn cross section during the impact while keeping a correct representation of the yarn longitudinal properties. Moreover, the proposed formulation provides new physical measurement to exploit the physic behind the impact and new possibilities in terms of failure modelisation.In the final part of the dissertation, the proposed yarn continuum model is introduced at the fabric level. Results confirmed the observation performed at the yarn level. The proposed hyperelastic approach is able to correctly represent the impact dynamic and fabric energies trends. Moreover, it provides more stability and a better representation of the fabric failure compared to linear elastic approach. The proposed hyperelastic constitutive law and the linear elastic one can be adopted for different portion of the same yarn without occurring into model instabilities and providing accurate results.The yarn mesoscopic model developed in the current work offers new possibilities in terms of failure modelisation and post processing tools. These could be used to develop more accurate fabric model and exploit the phenomena behind fabrics and yarns failure mechanic

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Zhou, Yu. "Simulation of High-velocity Penetration for Rigid Projectile into Plain Concrete Target using Discrete Element Method." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/31325.

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Penetration of high velocity is of concern for both civilian and military research for decades, and computerized simulation is the scholarâ s focus in recent years. This study presents a study on the Discrete Element Method (DEM) simulation of plain concrete targetâ s behavior under high-velocity penetration of rigid projectile. In this thesis, different types of research works including empirical, analytical and numerical methods in penetration by the previous scholars were carefully reviewed. A DEM-based concrete model was established by using software PFC3D. The major micro-variables of the simulation program were calibrated according to the required macro-mechanical parameters. Meanwhile, their correlations within the concrete range were studied, with the sensitivity analysis and the corresponding regression equations. With the established digital concrete model, penetration simulation tests were carried out. The results of penetration depth versus impact velocity were compared with the experimental and empirical calculated results from Forrestalâ s work in 1994. A good agreement was obtained. Some other simulation studies, like projectile mass, geometry, penetrating acceleration, concrete response stress, strain, and strain-rate were also conducted to study the constitutive properties in this thesis.
Master of Science

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Zach, Christine. "Die Erzählmotive der "Crône" Heinrichs von dem Türlin und ihre altfranzösische Quellen : ein kommentiertes Register /." Passau : Wissenschaftsverl. R. Rothe, 1990. http://catalogue.bnf.fr/ark:/12148/cb36658969n.

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Gutwald, Thomas. "Schwank und Artushof : Komik unter Bedigungen höfischer Interaktion in der "Crone" des Heinrich von dem Türlin /." Frankfurt am Main : Peter Lang, 2000. http://catalogue.bnf.fr/ark:/12148/cb39940375q.

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Kaiser, Isabel. "Urlaub auf dem Bauernhof : Erlebnisse aus dem Blickwinkel der Wissenschaft /." Hamburg : Diplomica-Verl, 2009. http://deposit.d-nb.de/cgi-bin/dokserv?id=3185288&prov=M&dok_var=1&dok_ext=htm.

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Boulangé, Guillaume. "Jacques Demy dispersé : Essai de généalogie artistique raisonnée." Montpellier 3, 2007. http://www.theses.fr/2007MON30007.

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« Tout film est inévitablement un palimpseste… » Comment un cinéaste peut-il hériter ? Selon quels modes, quels procédés ? A quelles fins ? Toujours évoquée mais rarement étudiée en tant que telle au cinéma, la question des influences est au cœur de l’œuvre du cinéaste français Jacques Demy. Qualifié à tort d’artiste maudit, l’auteur de Lola apparaît au contraire comme un « cas d’école » dans le cadre d’une étude de cinéma comparé. L’étude de sa généalogie artistique révèle en effet de surprenantes affinités électives. Quatre étapes distinctes se sont imposées dans le repérage et l’analyse méthodique de ces différents emprunts, traces ou indices de filiation, essaimés sur près de quatre vingts ans de création et qui composent le vaste portrait d’une communauté de goûts et d’esprit. Remonter d’abord aux sources de l’œuvre pour éclairer les rapports complexes de Jacques Demy à la cinémathèque et à la transmission ; disséquer ensuite au cœur des films les liens d’amour « fraternel » avec sa compagne et cinéaste Agnès Varda ; traiter de son influence discrète et problématique sur quelques compagnons élus de la Nouvelle Vague ; inventorier enfin les multiples formes que son héritage revêt et comprendre ce qui motive ses héritiers dans leur démarche de filiation. Que nous apprend cette enquête sur l’art de Jacques Demy et au-delà sur les mécanismes d’influence que son cinéma génère ? La filiation avec lui est toujours intéressée ; entre déférence, réactivation de sens, et iconoclastie, chaque créateur considère ce jeu intertextuel avec son cinéma comme le plus sûr moyen d’accéder à son identité. Ne serait-ce pas la particularité de toute œuvre profondément mémorable ?
“ A film is unavoidably a palimpsest” How does a film director inherit ? By which means and what procedures ? To what ends ? A concept such as influence has always been commonly used in all types of arts, but it has rarely been studied itself. The author of Lola, in spite of his unjustified reputation of being a rejected artist, proves to be on the contrary a perfect example in the realm of comparative cinema. Studying his artistic genealogy reveals surprising ancestors and sons. That survey highlighted four different factors as key points in the research and analysis of the different loans, traces or hints of connections to Demy’s works. Key factors that were picked over 80 years of artistic creation allow us to understand the cultural and spiritual basis of a certain community. Firstly returning to the beginning of his works to illustrate the complex relationship that Jaques Demy has with cinema and transmission. Next dissect the signs of his “fraternal” love with wife and fellow film maker Agnès Varda through his movies. Next is looking at his subtle but problematical influence on a few of Nouvelle Vague’s chosen companions. Finally list the miscellaneous forms of his legacy and work out what motivated those who claim being Demy’s heirs. What does one learn from this study of Jaques Demy’s talent and more-over the way his films have been an influence ? We will realise that claiming a filiation with Demy is never disinterested, anything from respect to iconoclasty, but it is first a way to assert one’s identity. Isn’t it the demonstration that his life works must be ranked among masterpieces ?

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Deml, Barbara. "Telepräsenzsysteme Gestaltung der Mensch-System-Schnittstelle /." [S.l.] : [s.n.], 2004. http://137.193.200.177/ediss/deml-barbara/meta.html.

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Maione, Riccardo. "Modélisation d’un système de pyrogazéification de la biomasse." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0088/document.

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Ce travail s’inscrit dans le projet LORVER, soutenu par la Région Grand Est et le FEDER. Il est destiné à créer une filière de production de biomasse végétale non alimentaire par valorisation de sites dégradés et de sous-produits industriels, en Lorraine. Un des procédés de valorisation de la biomasse produite est un procédé thermochimique de pyro-gazéification qui générerait de la chaleur et de l’électricité. Ce procédé, développé par SEA Marconi, se compose de trois réacteurs différents : un tambour tournant, pour la pyrolyse de particules de bois, la chaleur étant amenée par des billes d’acier chauffées ; un réacteur à vis sans fin pour l’oxydation du char qui permet de réchauffer les billes d’acier ; un réacteur de craquage des goudrons. L’objectif de cette thèse est de réaliser des modèles qui puissent permettre d’avoir une prédiction adaptée du comportement du système. Des modèles 3D du type DEM et CFD-DEM ont été conçus pour la modélisation des phénomènes qui interviennent dans le système. Les paramètres du modèle DEM ont été calibrés dans un tambour tournant de laboratoire. Pour le réacteur de pyrolyse, la simulation DEM a permis de prédire de façon satisfaisante la ségrégation pour des mélanges de billes d’acier et de particules non sphériques de bois, et de concevoir un modèle thermique et chimique 1D, sur lequel une étude de sensibilité a été effectuée. Un modèle CFD-DEM a été codé et validé sur un rhéomètre granulaire, permettant la simulation du réacteur d’oxydation partielle du char, qui n’a pas pu être réalisé dans le cadre de cette thèse
This work is part of the LORVER project, funded by Grand Est Région and FEDER. It aims to create a non-food biomass production chain by using and upgrading brownfields and industrial by-products in Lorraine. One possible valorization process of the produced biomass is a thermochemical pyro-gasification process that would generate heat and electricity. This process, developed by SEA Marconi, involves three different reactors: a rotating drum, for the pyrolysis of wood particles, the heat required being brought by hot steel balls; an Auger for partial oxidation of the char that allows heating the steel balls; a reactor for tar cracking. The aim of this thesis is to develop models that can predict the behavior of the system. 3D models based on DEM or CFD - DEM were designed for the modeling of phenomena involved in the system. The DEM model parameters were first calibrated in a rotating drum. The DEM simulation was able to predict in a satisfactory manner segregation between steel balls and non-spherical wood particles; it also helped to design a 1D thermal and chemical model, on which a sensitivity study has been done. A CFD - DEM model has been coded and validated on a granular rheometer allowing the simulation of the char oxidation reactor, even if this simulation was not possible during the PhD

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Aouina, Nizar. "Réduction électrochimique des ions nitrate et nitrite sur électrode de cuivre, en milieu neutre: Apport à la compréhension du mécanisme réactionnel." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00462788.

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Au cours de ce travail, le mécanisme réactionnel de réduction des ions nitrate à une électrode de cuivre en milieu neutre a été étudié et comparé aux résultats obtenus en milieux acide et alcalin. Pour ce faire, des études avec un des intermédiaires réactionnels, les nitrites, ont également été menées. En présence d'ions nitrate, trois vagues de réduction apparaissent sur le voltampérogramme vers -0,9, -1,2 et -1,3 V/ECS. Des mesures avec une électrode tournante nous ont permis de déterminer le nombre d'électrons échangés pour chaque vague, à savoir 2 (nitrites), 6 (hydroxylamine) et 8 (ammoniaque). Ces résultats ont été confirmés par voltampérométrie cyclique. Des électrolyses prolongées ont été effectuées en présence d'ions nitrate, à trois potentiels. Les analyses par spectrométrie UV-vis ont permis de détecter la présence de nitrites, hydroxylamine et ammoniaque au sein du catholyte. L'analyse par DEMS de la phase aqueuse a mis en évidence la production de protoxyde d'azote N2O à -1,2 V/ECS. Par ailleurs, une étude a été menée afin expliquer le blocage progressif de l'électrode de cuivre observé lors de la réduction des ions nitrate dans une cellule électrochimique à un seul compartiment. Ce blocage pourrait provenir du masquage des sites d'adsorption des ions nitrate par NO, ce dernier étant produit à la contre électrode suite à l'oxydation de l'ammoniaque par les radicaux hydroxyle. Enfin, la présence systématique d'une branche inductive sur les spectres d'impédance électrochimique (SIE) relevés lors de la réduction des ions nitrate constitue la signature d'un intermédiaire adsorbé impliqué dans le processus réactionnel. Finalement, l'étude SIE sur électrode tournante nous a permis de déterminer le coefficient de diffusion des ions nitrate à 25°C, valeur sur laquelle existait une certaine confusion dans la littérature. Cette valeur a conduit à une détermination précise du nombre d'électrons échangés lors de la réduction des ions nitrate.

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Liekis, Paulius. "Realaus laiko vizualizaciniai metodai demonstracinėse programose." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050530_120410-12537.

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This paper introduces a concept of demo arising mainly among people who have common interest in computer graphics and multimedia. The paper shows strong relationship between realtime visualization methods and the subject of this work, so-called demo programs. These programs are the most attractive production produced by community of demo-makers and also the ones most related to conceptual, mathematic and algorithmic fields of computer graphics. Methods used in demo programs varies from simple like „phong“ illumination model, generation of objects from layers, cartoon rendering style or bump-mapping, to complex: realtime ray-tracing, rendering of correct reflections or soft shadows. This work presents six demo programs made by author together with „Nesnausk!“ demo-makers group, also analyses available methods of edge detection and visualization, and describes the method proposed by author, which has distributed calculations between central and video card processors. This method is used as a main visualization effect in „Zenit“ demo program.

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Aouina, Nizar. "Réduction électrochimique des ions nitrate et nitrite sur électrode de cuivre, en milieu neutre : apport à la compréhension du mécanisme réactionnel." Paris 6, 2009. http://www.theses.fr/2009PA066323.

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Au cours de ce travail, le mécanisme réactionnel de réduction des ions nitrate à une électrode de cuivre en milieu neutre a été étudié et comparé aux résultats obtenus en milieux acide et alcalin. Pour ce faire, des études avec un des intermédiaires réactionnels, les nitrites, ont également été menées. En présence d’ions nitrate, trois vagues de réduction apparaissent sur le voltampérogramme vers -0,9, -1,2 et -1,3 V/ECS. Des mesures avec une électrode tournante nous ont permis de déterminer le nombre d’électrons échangés pour chaque vague, à savoir 2 (nitrites), 6 (hydroxylamine) et 8 (ammoniaque). Ces résultats ont été confirmés par voltampérométrie cyclique. Des électrolyses prolongées ont été effectuées en présence d’ions nitrate, à trois potentiels. Les analyses par spectrométrie UV-vis ont permis de détecter la présence de nitrites, hydroxylamine et ammoniaque au sein du catholyte. L’analyse par DEMS de la phase aqueuse a mis en évidence la production de protoxyde d’azote N2O à -1,2 V/ECS. Par ailleurs, une étude a été menée afin expliquer le blocage progressif de l’électrode de cuivre observé lors de la réduction des ions nitrate dans une cellule électrochimique à un seul compartiment. Ce blocage pourrait provenir du masquage des sites d’adsorption des ions nitrate par NO, ce dernier étant produit à la contre électrode suite à l’oxydation de l’ammoniaque par les radicaux hydroxyle. Enfin, la présence systématique d’une branche inductive sur les spectres d’impédance électrochimique (SIE) relevés lors de la réduction des ions nitrate constitue la signature d’un intermédiaire adsorbé impliqué dans le processus réactionnel. Finalement, l’étude SIE sur électrode tournante nous a permis de déterminer le coefficient de diffusion des ions nitrate à 25°C, valeur sur laquelle existait une certaine confusion dans la littérature. Cette valeur a conduit à une détermination précise du nombre d’électrons échangés lors de la réduction des ions nitrate.

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Шматько, Наталія Михайлівна. "Методичне забезпечення підтримки організаційно-комунікаційної стійкості об'єднання промислових підприємств." Thesis, Центр фінансово-економічних наукових досліджень, 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40879.

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Mazon, Correa Alves Gustavo. "EFFECTS OF YEAST-DERIVED MICROBIAL PROTEIN ON TRANSITION DAIRY COW HEALTH AND PERFORMANCE." UKnowledge, 2019. https://uknowledge.uky.edu/animalsci_etds/103.

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The transition period for dairy cows is defined as the three weeks pre and postpartum. During the transition period, dairy cows experience a myriad of metabolic, managerial, and nutritional requirement changes. These changes lead to stress and increased susceptibility to diseases which can negatively affect lactational performance in the short and long term. However, dietary amino acid availability can have a dramatic impact on the health and performance of dairy cows around parturition. Thus, the objective of the thesis was to evaluate the effects of supplementing yeast-derived microbial protein, as an alternative protein source for dairy cows during the transition period. This was accomplished by using visual observations and precision dairy monitoring technologies to record disease, feeding behavior, and performance of dairy cows from 21 days prepartum to 150 days postpartum. Yeast-derived microbial protein was found to decrease dry matter intake but not negatively affect milk production or health of the animals. Yeast-derived microbial protein may be used as an alternative protein source for transition dairy cows as it did not negatively affect milk production or health of the animals.

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Silva, Wanderson Oliveira da. "ELETROCATÁLISE DA OXIDAÇÃO DE ETANOL SOBRE CATALISADORES À BASE DE PtSnO₂: UM ESTUDO DE DEMS." Universidade Federal do Maranhão, 2013. http://tedebc.ufma.br:8080/jspui/handle/tede/964.

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Made available in DSpace on 2016-08-19T12:56:43Z (GMT). No. of bitstreams: 1 Dissertacao Wanderson.pdf: 6558678 bytes, checksum: 6817981e9e9dda09b67fbeb466f7115a (MD5) Previous issue date: 2013-02-18
Conselho Nacional de Desenvolvimento Científico e Tecnológico
The ethanol oxidation reaction was investigated using on line differential electrochemical mass spectrometry (DEMS) on carbon-supported Pt-SnO2 electrocatalysts at atomic ratio 1:1, 2:1 and 3:1 as a function of ethanol concentration and combined analysis of the reaction products and electrochemical measurements. The materials were prepared by two methods: impregnation/thermal decomposition with and without chemical reduction via sodium borohydride. They were characterized by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) techniques. A comparative study showed that the second method was more efficient to synthesize of these materials, which were chosen for DEMS and electrochemistry studies. Electrochemical measurements showed better faradaic current in lower potentials, indicating better activity to ethanol oxidation on PtSnO₂/C, Pt₂SnO₂/C and Pt₃SnO₂/C catalysts compared to Pt/C E-TEK. Pt/C E-TEK presented the best ratio between the CO₂ and acetaldehyde production in 0.01 mol Lˉ¹ ethanol, showing that this electrode favors the reaction via CO₂ production. When the ethanol concentration is increased, the ratio CO₂ /acetaldehyde decreases for all catalysts studied, mainly for Pt/C E-TEK. This increasing formation of acetaldehyde was largely responsible for the profile of faradaic currents in view of the onset for the formation of acetaldehyde to coincide with the beginning of the ethanol oxidation reaction. In general, the catalysts based on Pt-SnO₂ showed better performances for the ethanol reaction compared to Pt/C E-TEK, thus confirming the ability of SnO₂ to provide oxygen species for oxidize adsorbed intermediates such as CHx and OHads, at lower potentials.
A reação de oxidação de etanol foi investigada usando a espectrometria de massas eletroquímica diferencial on line (DEMS), sobre eletrocatalisadores de Pt-SnO₂ suportados em carbono Vulcan, com razão atômica 1:1, 2:1 e 3:1 em função da concentração de etanol e análises combinadas dos produtos reacionais e medidas de corrente eletroquímica. Os materiais foram preparados por dois métodos: impregnação/decomposição térmica com e sem redução química via borohidreto de sódio. Eles foram caracterizados pelas técnicas de energia dispersiva de raios X (EDX) e difratometria de raios X (DRX). Um estudo comparativo mostrou que o segundo método foi mais eficiente na síntese desses materiais, sendo escolhido para os estudos eletroquímicos e de DEMS. As medidas eletroquímicas mostraram melhores correntes faradáicas em menores potencias, indicando melhor atividade para a oxidação de etanol sobre os catalisadores PtSnO₂/C, Pt₂SnO₂/C e Pt₃SnO₂/C comparado com Pt/C E-TEK. A Pt/C E-TEK apresentou a melhor razão entre CO₂ e acetaldeído em etanol 0,01 mol Lˉ¹, mostrando que esse eletrodo favorece a via de formação de CO₂. Quando a concentração de etanol é aumentada, a razão CO₂/acetaldeído diminui para todos os catalisadores estudados, principalmente Pt/C E-TEK. Esse aumento na formação de acetaldeído foi o grande responsável pelo perfil de corrente faradáica, tendo em vista o início da reação de formação do acetaldeído coincidir com o início da reação de oxidação de etanol. Em geral, os catalisadores à base de Pt-SnO₂ apresentaram melhor desempenho para a reação de oxidação de etanol em relação a Pt/C E-TEK, confirmando assim a capacidade do SnO₂ em fornecer espécies oxigenadas para oxidar intermediários adsorvidos tais como CHx e OHads, em potenciais mais baixos.

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Vadluga, Vaidas. "Simulation of dynamic deformation and fracture behaviour of heterogeneous structures by discrete element method." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080213_082157-83281.

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Research area and topicality of the work. Mechanical properties and their evolution under loading are the most significant factors for the development of various mechanical structures, technologies and equipment. It seems to be natu-ral that deeper understanding of the behaviour of existing and design of new materials presents a challenge in different research areas. It should be noted, that all the materials are heterogeneous in meso- and micro- scales. They exhibit essential differences, compared to the macroscopic continuum behaviour. Basically, both experimental and numerical simulation methods are extensively applied for investigation purposes. Experimental techniques, capable of giving a realistic view of the inside of the material and extracting the real data, are very expensive. Therefore, the nu-merical simulation tools are extensively used as an alternative for investigation purposes. They have considerable advantages allowing the reproduction of multiple experiments and providing comprehensive data about ongoing phe-nomena. Recently, numerical technologies have become highly multidisciplinary subjects. They comprise phenomenological and statistical ideas, while mathe-matical models employ the relations of continuum mechanics, classical discre-tization methods and molecular dynamics. The Discrete Element Method (DEM) is one of new methods. It is aimed at simulating the dynamic behaviour of the contacting particles. Variable topology of the system of particles is an... [to full text]
Tyrimų sritis ir darbo aktualumas. Kuriant modernias ��vairios paskirties mechanines sistemas, technologijas ir įrangą, svarbiomis tampa jas sudarančios medžiagos. Savaime suprantama, kad žinomos ir naujai kuriamos medžiagos dabar kur kas išsamiau nagrinėjamos daugelyje mokslo šakų, įskaitant ir me-džiagų mechaniką. Visos medžiagos mezo- ir mikrostruktūros požiūriu yra ne-vienalytės. Jų mikroskopinės savybės skirtingos, lyginant su įprastu kontinuu-mu. Medžiagų savybėms tirti dažniausiai taikomi eksperimentiniai metodai. Eksperimentiniais metodais ištirti medžiagos struktūras ir jose vykstančius procesus ir įvertinti tam tikras jų savybes labai brangu. Tai viena priežasčių, kodėl skaitinis modeliavimas tampa realia tyrimų alternatyva. Skaitinį eksperi-mentą galima kartoti daug kartų, valdant bandinio parametrus, išlaikant tas pa-čias sąlygas, ir stebėti reiškiniui būdingus rodiklius visame tūryje. Šiuolaikiniai modeliavimo metodai yra kompleksiniai. Jie jungia fenome-nologines ir statistines idėjas, o matematiniai modeliai sudaromi taikant konti-nuumo mechanikos ir jų diskrečiųjų modelių bei molekulinės dinamikos pri-klausomybes. Diskrečiųjų elementų metodas (DEM) taip pat priskiriamas šiuo-laikinių metodų kategorijai. Jis skirtas kontaktuojančių dalelių sistemų dinami-niam modeliavimui. Kintanti dalelių sistemos topologija – būdingas metodo požymis. Pastaruoju metu DEM jau taikomas kontinuumui modeliuoti ir praktikoje aktualiems irimo uždaviniams spręsti. Reikia pastebėti... [toliau žr. visą tekstą]

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Santos, Suelen Silvana dos. "Direcionamento de antígenos para células dendríticas in vivo: uma nova estratégia para o desenvolvimento de vacina na paracoccidioidomicose." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-27052015-115437/.

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A paracoccidioidomicose (PCM) é a micose sistêmica mais frequente no Brasil. Na última década, foi demonstrado que é possível enviar antígenos diretamente para as células dendríticas utilizando o anticorpo αDEC205 e na presença de um estímulo de maturação, o resultado é a indução de uma resposta imunológica. Verificamos que o anticorpo αDEC fusionado ao peptídeo P10 induziu uma resposta por células produtoras de IFN-γ após uma única dose em relação à administração de P10, mesmo tendo sido administrado em uma concentração menor. Entretanto, essa resposta não se manteve após segunda dose do anticorpo. Após desafio dos animais com P. brasiliensis, imunizados com duas doses do anticorpo quimérico, detectamos níveis de IFN-γ e IL-4 no tecido pulmonar estatisticamente maiores no grupo αDEC/P10 e ISO/P10 em relação à administração de P10, todos em presença de Poly I:C. Em ensaios de terapia, verificamos no pulmão de camundongos tratados com o anticorpo quimérico, principal órgão envolvido em modelo animal de PCM, baixa concentração de IFN-γ e IL-10 em relação aos controles. Em adição, ficou evidente que nos animais tratados com o anticorpo αDEC/P10 o tecido pulmonar está compatível com o tecido de animais não infectados, enquanto que na ausência de tratamento adequado encontramos aglomerados de leveduras e um tecido com aumento no infiltrado celular. Esses achados indicam uma boa evolução clínica em animais tratados e indicam que o direcionamento do P10 através do anticorpo quimérico αDEC/P10, na presença de Poly I:C, é uma estratégia promissora para terapia contra P. brasiliensis.
Paracoccidioidomycosis (PCM) is the most common systemic mycosis in Brazil. In the last decade, it was demonstrated that antigens can be directly target to the dendritic cells using the antibody αDEC205 in the presence of a maturation stimulus, resulting in the induction of a strong immune response. We found that αDEC205 antibody fused to peptide P10 induced great response by IFN-γ producing cells after a single dose in relation to the administration of P10, although it has been administered in a lower concentration. However, this response was not maintained after second dose of antibody. Animals challenge with P. brasiliensis, after immunization with two doses of the chimeric antibody, produced high levels IFN-γ and IL-4 in lung tissue significantly higher in αDEC/P10 group in relation to the administration of P10, all in the presence of Poly I:C. In therapy assays, we found in the lungs of mice treated with the chimeric antibody, the main organ involved in an animal model of PCM, low concentration of IFN-γ and IL-10 compared to controls. In addition, it became evident that animals treated with αDEC/P10 antibody have a lung tissue much closer to that of non-infected tissue, while in the absence of suitable treatment we find clusters of yeasts and tissue filled with cellular infiltrates. Altogether, these findings show a clinical improvement in treated animals and indicate that targeting of P10 through the chimeric antibody αDEC/P10 in the presence of Poly I:C, is a promising strategy for therapy against P. brasiliensis.

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Silva, Dionisio Furtunato da. "Preparação de eletrocatalisadores PtRu/C e PtSn/C utilizando feixe de elétrons para aplicação como anodo na oxidação direta de metanol e etanol em células a combustível de baixa temperatura." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-23092011-155927/.

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Foram preparados eletrocatalisadores PtRu/C e PtSn/C utilizando feixe de elétrons para a redução dos íons metálicos em solução. Neste procedimento submeteu-se ao feixe de elétrons, sob agitação, soluções de água/etileno glicol (EG) e água/2- propanol, ambas contendo íons dos metais precursores e o suporte de carbono. Foram variadas as razões volumétricas água/2-propanol e água/etileno glicol, a razão atômica entre os metais, o tempo de irradiação e a taxa de dose. Os eletrocatalisadores obtidos foram caracterizados por análise de raios X por energia dispersiva (EDX), por difração de raios X (DRX), por voltametria cíclica (VC) e por espectroscopia Mössbauer. A atividade destes eletrocatalisadores na oxidação eletroquímica do metanol e do etanol foi avaliada por voltametria cíclica e cronoamperometria, utilizando a técnica do eletrodo de camada fina porosa, e pelas curvas de polarização obtidas em células a combustível unitárias operando diretamente com metanol e etanol. Os eletrocatalisadores PtRu/C preparados no meio reacional água/etileno glicol(EG) apresentaram razões atômicas diferentes das razões atômicas nominais. Os resultados sugerem que parte dos íons Ru(III) presentes no meio reacional não foram reduzidos. Os materiais obtidos apresentaram a fase cúbica de face centrada (cfc) da Pt e suas ligas e tamanhos de cristalito na faixa de 2 a 3 nm. Os eletrocatalisadores PtRu/C preparados em água/2- propanol apresentaram razões atômicas Pt:Ru similares às razões nominais. Os materiais obtidos apresentaram as fases cfc da platina e suas ligas e tamanhos de cristalito entre 3 e 4 nm. Os eletrocatalisadores PtSn/C preparados no meio reacional água/EG e água/2-propanol apresentaram razões atômicas Pt:Sn similares às razões nominais. Os materiais obtidos apresentaram as fases cfc da platina com tamanho de cristalitos na faixa de 2 a 4 nm e SnO2 (cassiterita). Os estudos sobre a oxidação eletroquímica de metanol e etanol mostraram que foi possível obter materiais com atividades similares e/ou superiores às atividades dos eletrocatalisadores comerciais PtRu/C (E-TEK) e PtSn/C (BASF), tidos como referência na área.
PtRu/C and PtSn/C electrocatalysts were prepared using electron beam irradiation. The metal ions were dissolved in water/2-propanol and water/ethylene glycol solutions and the carbon support was added. The resulting mixtures were irradiated under stirring. The effect of water/ethylene glycol and water/2-propanol (v/v) ratio, Pt:Ru and Pt:Sn atomic ratios, the irradiation time and dose rate were studied. The obtained materials were characterized by Energy dispersive analysis of X-rays (EDX), X-ray diffraction (XRD), cyclic voltammetry (CV) and Mössbauer spectroscopy. The electro-oxidation of methanol and ethanol were studied by cyclic voltammetry and chronoamperometry using the thin porous coating technique. The electrocatalysts were also tested on the Direct Methanol and Ethanol Fuel Cells. PtRu/C electrocatalysts prepared in water/ethylene glycol showed Pt:Ru atomic ratios different from the nominal ones. The results suggested that part of the Ru(III) ions were not reduced. The obtained materials showed the face-centered cubic (fcc) structure of Pt and Pt alloys with crystallite sizes of 2-3 nm. PtRu/C electrocatalysts prepared in water/2-propanol showed Pt:Ru atomic ratios similar to the nominal ones. The obtained materials also showed the fcc structure of platinum and platinum alloys with crystallite sizes of 3-4 nm. PtSn/C electrocatalysts prepared in water/ethylene glycol and water/2-propanol showed Pt:Sn atomic ratios similar to the nominal ones. The obtained materials showed the platinum (fcc) phase with crystallite sizes in the range of 2 - 4 nm and a SnO2 (cassiterite) phase. The obtained PtRu/C and PtSn/C electrocatalysts showed similar or superior performance for methanol and ethanol electro-oxidation compared to commercial PtRu/C (E-TEK) and PtSn/C (BASF) electrocatalysts.

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Spring, Ted. "Uncertainty comparison of Digital Elevation Models derived from different image file formats." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17193.

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Unmanned Aerial Systems (UAS) have become increasingly popular recently for surveying and mapping because of their efficiency in acquiring remotely sensed data in a short amount of time and the low cost associated with them. They are used to generate digital elevation models (DEM) derived from aerial photography for various purposes such as the documentation of cultural heritage sites, archaeological surveying or earthwork volume calculations. This thesis investigates the possible effects different file formats may have on the quality of elevation models. In this thesis, an UAS survey was simulated using a digital camera to produce six DEMs based on JPEG, TIFF and RAW format in Agisoft Photoscan by taking two sets of images of a city model, in different light conditions. Furthermore, a reference DEM was produced in Geomagic Studio using data from a Leica Nova MS50 Multistation. The DEMs were then compared in Geomagic Control. The results from the 3D comparison in Geomagic Control show that the standard deviation of all elevation models is 4 mm with the exception of the elevation model derived from raw-edited images taken with lighting, which has a standard deviation of nearly 6 mm. Also, all of the models have an average deviation of 0.4 mm or less. The significant deviations in all DEMs occur in areas where the multistation lacked vision of certain objects of the city model such as walls, or on the edges of the analysed area. Additionally, the georeferencing results from Photoscan show that the DEMs based on normal light condition images have slightly lower georeferencing errors than the DEMs with lighting. It has been concluded that it is difficult to say whether file formats have any noticeably effect on the uncertainty of digital elevation models.

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Gupta, Prashant. "Verification and validation of a DEM-CFD model and multiscale modelling of cohesive fluidization regimes." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10449.

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Fluidization of solid particles using gas flow is an important process in chemical and pharmaceutical industries. The dynamics of fluidisation are intricately related to particle scale physics. Fluid-particle interactions dominate gas-solid fluidization behaviour for particles with average size and density greater than 10-4 m and 103 kg/m3, respectively, classified as Geldart B and D particles. Inter-particle forces, such as cohesion, play an increasingly important role in the fluidization dynamics of smaller particles, which are classified as Geldart A and C. In particular, interesting fluidization regimes have been noticed for weakly cohesive Geldart A particles, exhibiting a window of uniform fluidization before the onset of bubbling behaviour. Despite widespread industrial interests, the fundamental understanding of the mechanisms that underlie these fluidization regimes is poor. The present study aims to improve the understanding of fluidization dynamics of Geldart A regimes using numerical simulations. A DEM-CFD model was employed to capture the widely separated spatial and temporal scales associated with fluidization behaviour. The model couples the locally averaged Navier-Stokes equation for fluid with a discrete description of the particles. The methodology and its computer implementation are verified and validated to assess the extent of fluidization physics that it is able to capture. Verification cases check the implementation of the inter-phase momentum transfer term, drag model implementation and pressure-velocity coupling. The test cases are employed in order to cover a wide range of flow conditions. Robust validation tests for complex fluidization phenomena such as bubbling, spouting and bidisperse beds have been conducted to assess the predictive capabilities of the DEM-CFD solver. The simulation results for time and spatially averaged fluidziation behaviour are compared to experimental measurements obtained from the literature, and are shown to have capture fluidization physics qualitatively. Robust features of bubbling fluidization, such as minimum fluidization velocity, frequency of pressure drop fluctuations, segregation rates and solid circulation patterns were captured. Furthermore, the DEM-CFD model is critically assessed in terms of model conceptualization and parameter estimation, including those for drag closures, particle-wall boundary conditions, bed height and particle shape effects. The validation studies establish modelling best-practice guidelines and the level of discrepancy against the analytical solutions or experimental measurements. Having developed the model and established its predictive capability, it is used to probe the hydrodynamics of weakly cohesive particles. Cohesive interactions are captured by employing a pair-wise van derWaals force model. The cohesive strength of the granular bed is quantified by the ratio of the maximum van der Waals force to the particle gravitational force, defined as the granular Bond number. The Bond number of the bed is increased systematically from 0-10 to examine the role of cohesion in the fluidization behaviour of fine powders while keeping the particle size and density constant across all the simulations. The idea was to segregate the hydrodynamics associated with size and density of the particles from the inter-particle interactions. The size and density of the particles are carefully chosen at a scale where inter-particle forces are present but minimal [Seville et al., 2000]. The Geldart A fluidization behaviour is captured for granular beds with Bond numbers ranging from 1 to 3. Many robust features of Geldart A fluidization, such as pressure drop overshoot, delay in the onset of bubbling, macroscopic Umf predictions and uniform bed expansion are captured in the DEM-CFD framework. The expanded bed was characterized according to criteria that the particles are highly immobile in this regime and the expanded porosity is related to inlet velocity by Richardson–Zaki correlations. Sudden jumps in the magnitudes of global granular temperature were found near the regime transitions. This observation was used an indicator of the onset of bubbling and quantification of minimum bubbling velocity (Umb). The window of the expanded bed regime (quantified as Umb - Umf) was shown to be an increasing function of cohesive strength of the bed. Furthermore, the stability of the expanded bed was probed by studying the response of the expanded bed to sudden inertial and voidage shocks. A kinematic wave, generated as a response to the voidage shock, was shown to slow down with increasing cohesion and decreasing hydrodynamic forces. Furthermore, predictions of Umb by DEM-CFD simulations for weakly cohesive beds were compared against empirical correlations by Valverde [2013] with an excellent match. Stress analysis of the expanded bed revealed the presence of tensile stresses. As the inlet velocity is increased beyond the minimum fluidization velocity, a longitudinal shift of these negative stresses is observed until they reach the top of the bed. Negative stresses were seen at the bed surface at the onset of bubbling. The role of cohesion stresses in the formation of expanded bed and suppression of bubbling was highlighted. Finally, the microstructure of the expanded bed was probed at different local micro and mescoscopic length scales. Evidence of clustering, agglomeration and cavities were presented in the expanded bed. Expanded bed expansion was shown to have mesostructural inhomogeneities present, which is contrary to the belief of homogeneous expansion.

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Krewson, Corey Nicholas. "Near Real-Time Flood Forecasts from Global Hydrologic Forecasting Models." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7476.

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This research assesses possible methods for extending the Streamflow Prediction Tool from a streamflow forecasting model to a flood extent forecasting model. This new flood extent forecasting model would allow valuable and easy to understand information be disseminated in a timely manner for flood preparation and flood response. The Height Above Nearest Drainage (HAND) method and AutoRoute method were considered for flood extent models but the HAND was the better option for its simple and quick computation as well as its viability on a global scale. Due to the importance of Digital Elevation Models (DEMs) in these flood extent models, an analysis was performed on the sensitivity and response of different DEMs with the HAND method. The HAND method with the differing DEMs was also analyzed using the Streamflow Prediction Tool for model boundary conditions against Sentinel-1 SAR generated flood extent images from August 24, 2017. The MERIT DEM performed the best in this analysis and is recommended for future research in creating a global forecasting flood extent model. The HAND method covered about 25% of the generated flood extent images and more complex flood extent models may need to be considered in areas where HAND underperforms. Finally, a proof of concept flood extent model was created and deployed as a web application for easy accessibility and distribution of flood information. Additional research to consider is flood impact based on affected population or an economic analysis, as well as optimizing model parameters for increased accuracy and performance. Additional research is also needed for HAND DEM analysis in other parts of the world.

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Maciel, Karina Almeida. "Fatores de virulência de escherichia coli isoladas de aves abatidas no estado do Tocantins." Universidade Federal do Tocantins, 2016. http://hdl.handle.net/11612/555.

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O setor avícola desempenha importante papel na economia brasileira. Com a intensificação da produção de aves surge a necessidade de ferramentas que auxiliem na detecção correta dos microrganismos responsáveis por perdas produtivas. O Tocantins por possuir território disponível e condições climáticas, tais como calor e umidade que aperfeiçoam a produção desta espécie, propicia também a proliferação de patógenos, necessitando de diagnósticos precoces. A Escherichia coli (E. coli) é uma bactéria Gram-negativa encontrada na microbiota normal de animais de produção. No entanto, existem espécies patogênicas que são responsáveis por perdas produtivas na avicultura devido a problemas como as condenações durante o abate. Atualmente, estas cepas estão separadas em categorias de acordo com seus fatores de virulência, responsáveis pelos mecanismos de fisiopatogenia, tanto animal quanto em humano. Os fatores de virulência vão desde a liberação de toxinas, até a presença de genes específicos que estabelecem a patogenia no hospedeiro. A correta identificação de cada categoria desta bactéria por meio da detecção da presença de fatores de virulência com o auxílio da biologia molecular assume papel fundamental para possíveis decisões em profilaxia e aprimoramento do manejo, com intuito de minimizar perdas produtivas. Atualmente, são escassos trabalhos que identifiquem lesões extras intestinais em aves ocasionadas por E. coli diarreinogênicas, assim o objetivo do presente trabalho foi demonstrar a associação de lesões em aves com patotipos de E. coli comumente detectadas em mamíferos.
The poultry sector plays an important role in the Brazilian economy. With the intensification of poultry production comes the need for tools to assist in the correct detection of microrganisms responsible for production losses. Tocantins to own land available and weather conditions such as heat and humidity that enhance the production of this species, also favors the proliferation of pathogens, requiring early diagnosis. Escherichia coli (E. coli) is a Gram-negative bacteria found in the normal microflora of farm animals. However, there are pathogenic species which are responsible for production losses in poultry due to problems such as sentences during slaughter. Currently, these strains are separated into categories according to their virulence factors responsible for the pathogenesis mechanisms, both animal and human. The virulence factors ranging from the release of toxins to the presence of specific genes which provide for the pathogenesis in the host. The correct identification of each category of the bacteria through detecting the presence of virulence factors with the aid of molecular biology plays a critical role in possible decisions prophylaxis and improvement of handling, in order to minimize production losses. Currently, there are few studies that identify intestinal extra injuries caused by poultry E. coli diarrheagenic, so the aim of this study was to demonstrate the association of diseases in poultry with pathotypes of E. coli commonly found in mammals.

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Jurca, Ciprian Bogdan. "Synthèse et caractérisation de pérovskites doubles magnétorésistives dérivées de Sr2FeMoO6." Paris 11, 2004. http://www.theses.fr/2004PA112275.

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Cette thèse concerne la synthèse et l'étude des propriétés physico-chimiques des pérovskites doubles Sr2FeMoO6, Sr2FexMo2-xO6 (x = 0,9-1,33) et Sr2FeCrxMo1-xO6 (x = 0,1-0,25). Pour Sr2FeMoO6 les conditions de synthèse à l'état solide influencent la microstructure des échantillons et l'ordre Fe/Mo. Des frittages successifs avec des broyages intermédiaires entraînent ainsi une augmentation de l'aimantation à saturation (3,8 µB) qui s'approche de la valeur idéale (4 µB) et améliorent la magnétorésistance en champ faible (LFMR) de 1,58±0,14 % à 2,74±0,01 % (T = 300 K, H = 1 kOe) en raison des modifications microstructurales. Les valeurs des moments magnétiques effectifs montrent la présence de valences mixtes: FeII/MoVI et FeIII/MoV. Les compositions Sr2FexMo2-xO6 (quadratiques ou cubiques pour x > 1,2) acceptent un plus grand excès de fer que de molybdène. L'ordre Fe/Mo diminue quand x s'écarte de 1 et tend vers une valeur d'équilibre après un grand nombre de traitements de frittage pour un x donné. La Tc augmente avec x (couplages Fe-Fe plus forts que les couplages Fe-Mo), tandis que l'aimantation à saturation est maximum pour x = 1. La résistivité augmente avec x (les électrons délocalisés proviennent du molybdène), elle dépend davantage de la composition chimique que de la microstructure. La magnétorésistance est maximum pour x = 1; pour x = 1,33 le matériau cesse d'être un demi-métal. Pour la série Sr2FeCrxMo1-xO6 l'augmentation du contenu en chrome détermine la diminution de l'ordre des cations sur les sites octaédriques et par conséquent une baisse de Tc, d'aimantation et de magnétorésistance
This work is devoted to the synthesis and physico-chemical characterization of Sr2FeMoO6, Sr2FexM02-xO6 (x = 0. 9-1. 33) and Sr2FeCrxMo1-xO6 (x = 0. 1-0. 25) double perovskites. For Sr2FeMoO6 the solid state synthesis conditions influence the microstructure of the samples and the Fe/Mo order. Successive sintering treatments with intermediate grindings improve the saturation magnetization (3. 8 µB) which became close to the ideal value (4 µB) and the low field magnetoresistance (LFMR) from 1. 58±0. 14 % to 2. 74±0. 01 % (T = 300 K, H = 1 kOe) as a consequence of microstructural changes. The effective magnetic moment values depict the presence of mixed valency states: FeII/MoVI and FeIII/MoV. The Sr2FexMO2-xO6 solid solutions (tetragonal symmetry or cubic for x > 1. 2) are stable for a larger excess of iron than of molybdenum. The Fe/Mo order diminishes when the difference between x and 1 becomes larger and is stabilizing to an equilibrium value alter a high number of sintering treatments for a given x. The Tc arises with x (Fe-Fe couplings stronger than Fe-Mo), but the saturation magnetization is maximum for x = 1. The resistivity enhances with x (delocalized electrons come from molybdenum) presenting thus a stronger dependence of the chemical composition than the microstructure. The magnetoresistance is maximum for x = 1 ; for x = 1. 33 the composition ceases to be a half-metal. For Sr2FeCrxM01-xO6 solid solutions, the increase of chromium content determines the diminution of octahedral sites cationic order and thus a decrease of Tc, magnetization and magnetoresistance

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Costa, Márcio Leonardo Monteiro. "Modelos de circulação do mp3-demo através da internet: um estudo de caso sobre música independente no Maranhão." Universidade Federal de Pernambuco, 2008. https://repositorio.ufpe.br/handle/123456789/2971.

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Made available in DSpace on 2014-06-12T16:25:38Z (GMT). No. of bitstreams: 2 arquivo1874_1.pdf: 2422278 bytes, checksum: 4de72500f0cad2d6e7e3b52c96de4328 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008
Este trabalho analisa o fenômeno da circulação de música independente através da internet a partir da popularização do formato mp3 como padrão de compartilhamento. A dissertação está dividida em duas partes, sendo a primeira, marcada por uma problematização a respeito do novo ambiente comunicacional e suas implicações sobre a livre troca de conteúdos, complementada por uma descrição da situação dos artistas autônomos face às reconfigurações pelas quais passa a indústria da música. Na segunda parte, tomando como opção metodológica o estudo de caso, descreve-se o funcionamento dos espaços mais representativos da internet onde se observa a difusão do mp3-demo. Adotam-se como corpora da pesquisa artistas maranhenses que fazem uso destes espaços visando maior divulgação de seu trabalho. Como resultado, avaliamos as mudanças na cadeia produtiva da música e seus reflexos sobre os modelos autônomos de produção, circulação e consumo

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Tsuruta, Naoki. "Improved Particle Method with High-Resolution and Computational Stability for Solid-Liquid Two-Phase Flows." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188536.

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47

Näslund, Allan. "Webbsida och demo-EP." Thesis, Blekinge Tekniska Högskola, Sektionen för teknokultur, humaniora och samhällsbyggnad, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1475.

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Syftet med detta kandidatarbete var att sätta samman ett promopaket bestående av en webbsida och en demo-EP med passande grafisk design. EP:n har tre spår elektroakustisk instrumentalmusik av skiftande karaktär, samt ett stilrent men ändå suggestivt omslag. Webbsidan är till för att presentera mig själv och mitt arbete (inte bara musik), och är byggd med hjälp av HTML, PHP, CSS och MySQL.
The purpose of this bachelor exam project was to compile a promo package consisting of a website and demo EP with suitable graphic design. The EP has three tracks of electro acoustic instrumental music of varying character, as well as stylistically pure yet suggestive cover artwork. The website is a presentation of myself and my work (not just music), and was built using HTML, PHP, CSS and MySQL.
Detta är en reflektionsdel till en digital medieproduktion.

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Terreros, Iñigo. "Modélisation DEM thermo-mécanique d'un milieu continu. Vers la simulation du procédé FSW." Phd thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 2013. http://pastel.archives-ouvertes.fr/pastel-00996971.

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De nos jours, la gestion des flux de matière autour de la zone decontact représente un des principaux verrous scientifiques pourl'amélioration des simulations des procédés d'usinage comme, parexemple, le procédé FSW. Les méthodes basées sur la mécanique desmilieux continus sont couramment utilisées dans ces simulations maiselles rencontrent de nombreuses difficultés dans les zones decontact. Une explication "physique" à ces difficultés estl'utilisation des équations issues de la mécanique des milieuxcontinus pour décrire des phénomènes discontinus. À ce point, laméthode des éléments discrets s'est révélée être une alternative auxapproches continues pour traiter le problème causé par cesdiscontinuités. Cette méthode est en revanche très gourmande en termede temps de calcul.Une solution à long terme passe par un couplage entre méthodescontinues et discrètes qui requiert une zone de recouvrement où lesdeux approches coexistent. Cette zone est classiquement placée dansune région continue et cela oblige à développer la méthode deséléments discrets pour qu'elle puisse opérer dans ce type derégion. Le travail de thèse présente une méthode pour simuler laconduction de la chaleur et le comportement mécanique des milieuxcontinus élasto-plastiques. Cette méthode peut travailler dans la zonecontinue de recouvrement et, en plus, elle peut être facilementcouplée avec les méthodes discontinues classiques.Le couplage entre l'aspect thermique et l'aspect mécanique estégalement étudié et comparé aux résultats expérimentaux issus de labibliographie.

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Kneib, François. "Force moyenne et fluctuations subies par un obstacle indéformable soumis à l’écoulement confiné d’un milieu granulaire." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI024/document.

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Les études existantes s'intéressant au dimensionnement des structures paravalanches s'appuient généralement sur des signaux de force lissés dans le temps. Cependant, le caractère hétérogène de la neige en écoulement est responsable de fortes fluctuations systématiquement observées. Cette thèse a pour objectif de caractériser les fluctuations de force exercées sur un obstacle surversé par un écoulement granulaire. Des modélisations numériques par la méthode des éléments discrets sont mises en œuvre pour simuler l'interaction entre la neige, représentée par un ensemble plan de particules sphériques, et un mur immobile et indéformable. Une particularité de ce travail réside dans l'étude d'une gamme très large de régimes d'écoulement, de quasistatique à collisionnel. Deux systèmes modèles sont développés dans le but de focaliser la zone d’étude en amont de l’obstacle, et de permettre le contrôle des variables macroscopiques de l’écoulement (vitesse de cisaillement, pression de confinement, tailles des systèmes). Le premier confine les grains entre quatre parois dont l’une impose un cisaillement à vitesse constante, alors que les signaux de force sont mesurés sur la paroi faisant face au cisaillement. Le second système confine les grains entre deux parois (dont une cisaillante) et une condition aux limites périodique dans la direction du cisaillement, alors que le mur est immergé dans les grains. Chaque système est étudié via une analyse moyenne puis les fluctuations sont caractérisées à partir des signaux de force instantanés.Le nombre inertiel macroscopique construit sur la vitesse de cisaillement et la pression de confinement imposées au système s'avère être une variable de contrôle à la fois de la dynamique moyenne et des fluctuations dans les deux systèmes. Une loi empirique a été établie pour chacun des systèmes pour prédire la transmission de force moyenne sur l'obstacle en fonction du nombre inertiel macroscopique, et la mesure de grandeurs locales a révélé que la loi rhéologique µ(I) des milieux granulaires en écoulement est respectée quasiment partout. Les autocorrélations des signaux de force sur le mur à l'échelle mésoscopique ont révélé l'existence d'un effet mémoire des systèmes aux faibles nombres inertiels, disparaissant avec la transition vers le régime dense inertiel. Les distributions de forces à trois échelles spatiales différentes sont également contrôlées par le nombre inertiel macroscopique : aux régimes lents les distributions sont resserrées et approchent une forme Gaussienne, aux régimes rapides les distributions sont exponentielles. Des lois de probabilité log-normales tronquées à trois paramètres ont été établies afin de prédire de façon empirique les distributions de force sur l'obstacle.Ce travail contribue à approfondir les connaissances sur la composante moyenne et les fluctuations de force subies par un obstacle soumis à un écoulement granulaire. Les résultats obtenus permettent d'envisager la modélisation de systèmes gravitaires s'approchant des conditions réelles d'écoulements, permettant ainsi la comparaison avec des expérimentations de laboratoire dans le but de mieux dimensionner les structures de génie-civil
The existing studies dealing with the design of civil-engineering structures against snow avalanches are generally based on force times series that are smoothed over time. However the strong heterogeneity of snow leads to systematic observations of a high level of force fluctuations. This PhD thesis aims at characterizing the force fluctuations exerted on an obstacle that is overflowed by a granular flow. Numerical simulations based on the discrete elements method are implemented to model the interaction between the snow, represented by an assembly of spherical particles, and a rigid motionless wall-like obstacle. A key feature of this work is the broad range of flow regimes investigated, from quasistatic to collisionnal. Two model systems are studied in order to focus on a zone restricted to the upstream of the obstacle, and to allow a full control of the macroscopic flow variables (shearing velocity, confinement pressure, system sizes). The first one confines the grains between four walls from which the top one imposes a constant shearing velocity while the force signals are measured on the wall facing the corresponding displacement. The second system confines the grains between a static bottom wall, a shearing top wall, and a periodic boundary condition in the shear direction, while the wall-like obstacle is fully immersed in the grains. Each system is studied through a time-averaged analysis then the fluctuations are characterized from the instantaneous force time series.The macroscopic inertial number built from the shear velocity and the confinement pressure imposed to the system turns out to be the main control variable of both the mean dynamics and the fluctuations in the systems. An empirical law has been established to predict the mean force transmission on the obstacle as a function of the macroscopic inertial number for each of the two systems, and the measurement of local strain and stress tensors revealed that the granular flow µ(I)-rheological law is respected nearly everywhere in the samples. The autocorrelations of force signals on the obstacle at the mesoscopic scale revealed the presence of a memory effect of both systems at low inertial numbers which vanishes with the transition from the quasistatic to the dense inertial flow regimes. The force distributions at three different spatial scales are also controlled by the macroscopic inertial number: for slow regimes the distributions are tightened and resemble Gaussian shapes, for fast regimes the distributions are rather exponential. Truncated log-normal probability density functions (with three parameters) have been established in order to predict empirically the force distributions on the obstacle.This work contributes to advance the knowledge on both the time-averaged and the fluctuating components of the force exerted on a wall subjected to a granular flow. The results enable to look forward with the modeling of gravity-driven systems approaching real flow conditions, thus allowing a comparison with laboratory experiments and full-scale measurements, with the aim of better designing of civil engineering structures impacted by avalanches

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Marechal, Ewen. "Etude du colmatage des systèmes carburant de turboréacteurs par des suspensions denses de particules de glace." Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0002/document.

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Dans certaines conditions de température et de débit, l’eau naturellement présente dans le kérosène va givrer l’intérieur des conduites du système carburant avion. Ces dépôts peuvent libérer des particules de glace qui sont entrainées par l’écoulement, et provoquent le colmatage des équipements hydrauliques situés en aval. Ce phénomène fut mis en évidence suite à l’accident d’un Boeing 777 en 2008, aussi sa compréhension est un enjeu important pour les acteurs de l’industrie aéronautique. Un dispositif a été spécialement conçu pour reproduire cette menace de façon quantifiée. De l’eau est atomisée dans un écoulement à basse température, puis cristallise pour former une suspension qui vient colmater différentes cibles perforées. Les températures, débits et pertes de charge sont mesurées, et le phénomène est filmé par une caméra haute fréquence. Un modèle a été réalisé à partir de cesobservations, complétées par des données issues de la littérature et de retoursd’expérience. Pour la phase fluide, les équations de Navier-Stokes incompressibles sont résolues par une approche volumes finis. Le couplage pression-vitesse est obtenu par l’algorithme SIMPLE et l’ordre élevé au moyen de la méthode MLS. La phase solide est simulée par éléments discrets. L’interaction fluide-particules repose sur une approche de type milieu poreux. Un code CFD-DEM parallèle a été développé, et les premières simulations d’écoulement en milieu granulaire sont en bon agrément avec des résultats expérimentaux
Water, which exists naturally in jet-engine fuel, may freeze within theaircraft fuel pipes under certain temperatures and flow rates. The ice particles released by these deposits are entrained by the flow, and clog the hydraulics downstream. The understanding of this phenomenon, highlighted by the crash of a Boeing 777 in 2008, is an important issue for the aviation industry. Therefore a device has been designed to reproduce this threat in a controlled and quantified way. Water is atomized in low temperature jet-engine fuel and the droplets crystallize. The resulting slurry clogs different kinds of perforated targets. Temperatures, flow rates and pressure drops are monitored, and the phenomenon is filmed by a high frequency camera. A model was constructed based on these observations and data from literature and feedbacks. For the fluid phase, the incompressible Navier-Stokes equations are solved within a finite volume framework. The pressure-velocity coupling is achieved using the SIMPLE algorithm and high order of accuracy thanks to the MLS method. The solid phase is simulated using discrete elements. The fluid-particle interaction is based on a porous medium approach. A CFD-DEM parallel code has been developed to run the model. The first simulations of flow through granular media are in good agreement with experimental results

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Dissertations / Theses on the topic 'DEMC'

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