• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 51
  • 42
  • 16
  • 13
  • 11
  • 8
  • 6
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 163
  • 21
  • 17
  • 16
  • 13
  • 11
  • 10
  • 10
  • 10
  • 10
  • 10
  • 9
  • 9
  • 9
  • 9
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Waffen-SS military units in Estonia, Croatia and the Polish Ukraine

Campbell, Bruce B. January 1978 (has links)
Thesis (M.A.)--Wisconsin. / Includes bibliographical references (leaves 221-225).
32

Espectrometria de absorção atômica com tubo aquecido na chama e amostragem direta de sólidos para determinação de manganês e níquel em coque de petróleo / Solid sampling flame furnace atomic absorption spectrometry for manganese and nickel determination in petroleum coke

Bizzi, Cezar Augusto 28 July 2009 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A solid sampling flame furnace atomic absorption spectrometry (SS-FF-AAS) system was developed in this work for Mn and Ni determination in petroleum coke. The proposed solid sampling system was made in quartz, with two perpendicular tubes (T-shaped tube), adapted on the burner. Determination was made using an atomic absorption spectrometer with deuterium background corrector, using an air + acetylene flame and a single slot burner. Sample pellets up to 62 mg were introduced into the quartz device cell with a movable hollow quartz piston. When the sample pellet reaches the end of quartz cell, in the presence of oxygen flow, it quickly burns and the combustion products are transferred to the upper slot tube where the absorption atomic process happens. Calibration step was performed using aqueous standards applied directly on high purity graphite pellets and different masses of petroleum coke certified reference material (CRM). The results obtained for Mn and Ni using proposed SS-FF-AAS were compared to those obtained by inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry after sample decomposition step by microwave assisted acid digestion (high pressure) and microwave induced combustion resulting in agreement higher than 96%. In addition, the agreement for Mn and Ni in CRM (coal and petroleum coke) was 96.3 ± 8.7% and 98.2 ± 3.0%, respectively. The relative standard deviation was lower than 9% for both analytes. Characterist masses were 18.3 ± 1.8 ng for Mn and 14.7 ± 1.4 ng for Ni and limit of detection were 0.64 and 0.82 μg g-1 for Mn and Ni, respectively. The throughput was 9 determinations per hour, including drying, weighing and pressing. The proposed SS-FF-AAS system can be applied for Mn and Ni determination in petroleum coke, combining high sample throughput, precision and accuracy. / Neste trabalho foi proposto um sistema de espectrometria de absorção atômica com tubo aquecido na chama e amostragem direta de sólidos (SS-FF-AAS) para a determinação de Mn e Ni em amostras de coque de petróleo. O sistema proposto para amostragem direta de sólidos foi construido em quartzo, com dois tubos perpendicularmente sobrepostos, em forma de T , adaptado a um espectrômetro de absorção atômica, com chama ar + acetileno, empregando um queimador do tipo monofenda e corretor de fundo com lâmpada de deutério. A amostra, na forma de comprimidos de até 62 mg, foi introduzida na cela de quartzo com o auxílio de um êmbolo de quartzo. Ao atingir a região da cela posicionada sobre o queimador, na presença de O2, a amostra entra em combustão e os vapores gerados são carregados até o tubo superior, onde ocorre o processo de absorção atômica. A calibração foi feita utilizando solução de referência aquosa transportada sobre comprimidos de grafite de alta pureza e, também, com diferentes massas de material de referência certificado (CRM) de coque de petróleo. Os resultados obtidos para Mn e Ni empregando o sistema SS-FF-AAS apresentaram concordância superior a 96% em comparação com resultados obtidos por espectrometria de emissão óptica com plasma indutivamente acoplado e espectrometria de massa com plasma indutivamente acoplado após decomposição das amostras por via úmida assistida por radiação micro-ondas (sistema de alta pressão) e por combustão iniciada por micro-ondas. Adicionalmente, a concordância para Mn e Ni em CRM (carvão e coque de petróleo) foi de 96,3 ± 8,7% e 98,2 ± 3,0%, respectivamente. O desvio padrão relativo foi inferior a 9% para ambos os elementos. A massa característica obtida foi de 18,3 ± 1,8 ng para Mn e de 14,7 ± 1,4 ng para Ni e o limite de detecção foi de 0,64 e 0,82 μg g-1 para Mn e Ni, respectivamente. A freqüência de determinações foi de 9 amostras por hora, incluindo as etapas de secagem, pesagem e prensagem. Desta forma, o sistema SS-FF-AAS proposto mostrou-se uma boa alternativa para determinação de Mn e Ni em coque de petróleo, agregando rapidez, precisão e exatidão.
33

The remarkable outflows from the galactic microquasar SS433

Jeffrey, Robert January 2016 (has links)
In this thesis, I present 4 new, high-resolution observations of the Galactic microquasar SS 433, obtained from the Very Long Baseline Array (VLBA). I show that we can resolve the same ejecta in successive observations separated by ~ 35 d. I will demonstrate a method to uniquely determine launch vectors of the jet bolides, and I use this unprecedented baseline in time to show that the expansion rate of these bolides may reach 0.03c. I also present the first scientific results from the study of the radio jets in a unique set of historic observations of SS 433: the 39 images that comprise the 2003 VLBA movie of Mioduszewski et al. (2004). This unmatched time sampling allows us to see daily changes in the dynamics of SS 433's jets. I present evidence that these observations caught SS 433 as it transitioned from quiescence into a flare, and I show that this manifests itself as an increase in both the jet launch speed and the brightness of the jet bolides. Using these data, I examine the evolution of the particle energies, densities and magnetic fields within the bolides. We see that the estimates of the mass-loss rates via the jets cannot be reconciled with the those inferred from X-ray or optical data, if we posit equipartition of energy in synchrotron emitting plasma. The time resolution of the 2003 data allows us to observe the flux evolution of the jet bolides, and I show that the bolides undergo a power law decay as t<sup>−2.8</sup>. Lastly, I examine X-ray monitoring data from the Swift/BAT satellite and the MAXI All-Sky- Monitor. From these lightcurves, I examine the geometry of the X-ray emission from close to the compact object itself, and I discuss SS 433's place within the current paradigm of accretion in microquasars. Throughout, we will see that it is the accessible time scales of the SS 433 phenomenon that allow us to learn about its exciting, complex physics.
34

Estudo do bio-óleo e carvão obtido a partir do lodo de tratamento de esgoto sanitário por conversão à baixa temperatura.

DANTAS FILHO, Francisco Ferreira. 24 September 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-24T13:47:14Z No. of bitstreams: 1 FRANCISCO FERREIRA DANTAS FILHO - TESE (PPGEP) 2013.pdf: 1757426 bytes, checksum: 5a54b650a305bfccca48540f2323f279 (MD5) / Made available in DSpace on 2018-09-24T13:47:14Z (GMT). No. of bitstreams: 1 FRANCISCO FERREIRA DANTAS FILHO - TESE (PPGEP) 2013.pdf: 1757426 bytes, checksum: 5a54b650a305bfccca48540f2323f279 (MD5) Previous issue date: 2013-04-20 / CNPq / O presente trabalho discorre sobre uma alternativa para mitigar o problema do Lodo de Esgoto Sanitário – LES. Esse resíduo influencia negativamente de várias formas o meio ambiente, destacando-se a poluição das águas superficiais e subterrâneas. Teve como objetivo utilizar a biomassa presente no LES para a produção de combustíveis (Bio-óleo e Carvão). Tratou-se de um estudo experimental com a biomassa obtida na Estação Experimental de Tratamento Biológico de Esgotos Sanitários – EXTRABES, localizada na cidade de Campina Grande – PB. O experimento foi realizado em duas etapas: a primeira correspondente ao estudo termogravimétrico e cinético do LES; a segunda, a obtenção do bio-óleo e carvão oriundo da pirólise do LES, realizado no LABCON, instalado na Universidade Federal Fluminense – UFF. Os resultados obtidos do estudo termogravimétrico nas três razões de aquecimento 5,10 e 15ºC.min-1, constatam uma estabilidade térmica a 30ºC sobre atmosferas de ar sintético e N2. No estudo cinético determinaram-se os seguintes parâmetros: Energia de Ativação (Ea), Fator de frequência (A-1), Desvio padrão (sd) e o Coeficiente linear (r), que foram calculados por termogravimetria pelos métodos Coats-Redfern (CR); Madhusudanan (MD); Van Krevelen (VK) e Horowitz-Metzger (HM). Os espectros de FTIR da amostra do LES apresentaram bandas referentes à água, matéria orgânica e óxidos de silício. O bio-óleo foi obtido através do processo da conversão à baixa temperatura, em atmosfera de nitrogênio, atingindo 380°C com tempo de detenção de 2h. O proc esso de pirólise do LES resultou em 9% de bio-óleo, 57% de carvão e 34% de água de pirólise. Observou-se que o bio-óleo obtido é uma mistura complexa de hidrocarbonetos alifáticos, aromáticos, esteróides, compostos oxigenados e nitrogenados, que foi identificada pelas técnicas FTIR, RMN 1H, CG-EM. O carvão apresentou baixa área superficial, não sendo considerado potencialmente bom suporte catalítico, tanto pela metodologia de Langmuir, SLANG 0,748 m2.g-1 quanto por BET, SBET = 0,695m2.g-1. Os resultados confirmam que à Conversão à Baixa Temperatura é uma técnica promissora, tanto para o destino do LES, quanto para obtenção de biocombustíveis. / The present study discusses an alternative to mitigate Sewage Sludge – SS problem. This residue adversely affects the environment in various ways, highlighting pollution of surface and groundwater. It aimed to use the biomass present in the SS for fuel production (Biooil and coal). It was an experimental study with biomass obtained from the Estação Experimental de Tratamento Biológico de Esgotos Sanitários – EXTRABES, located in the city of Campina Grande – PB. The experiment was conducted in two stages: first corresponding to thermogravimetric and kinetic study of the SS; second, obtainment of biooil and coal originated from the pyrolysis of SS, conducted at LABCOM, installed at the Fluminense Federal University – FFU. The results obtained from the thermogravimetric study in the three heating rates 5, 10 and 15oC min-1, found a thermal stability at 30°C on atmospheres of synthetic air and N2. In the kinetic study the following parameters were determined: Activation Energy (Ea), frequency factor (A-1), standard deviation (sd) and linear coefficient (r), that were calculated by thermogravimetry by the Coats-Redern (CR); Madhusudanan (MD); Van Krevelen (VK) and Horowitz-Metzger (HM) methods. The FTIR spectrums from the SS sample presented bands related to water, organic matter and silicon oxides. The biooil was obtained through the conversion at low temperature process, in nitrogen atmosphere, reaching 380oC with holding time of 2h. The pyrolysis process of the SS resulted in 9% of biooil, 57% of coal and 34% of pyrolysis water. It was observed that the biooil obtained is a complex mixture of aliphatic hydrocarbons, aromatics, steroids, nitrogenous and oxygenated compounds, which was identified by the FTIR, RMN 1H, CG-EM techniques. The coal presented low superficial area, not being considered a potentially good catalytic support, by the Langmuir methodology, SLANG 0,748 m2.g-1 as well as the BET, SBET = 0,695m2.g-1. The results confirm that the Conversion at Low Temperature is a promising technique, for both the destination of the SS as well as for the obtainment of biofuels.
35

Development and application of novel fusion approaches for elemental analysis of carbon-based materials

Simoes, Filipa R. F. 16 November 2020 (has links)
Graphite and graphitic materials underpin a number of modern technologies such as electrodes for energy storage and conversion systems. Due to their aromatic honeycomb-type lattice and layered structure, these carbons host a rich variety of foreign elements in their interstices. Whether possessing a tubular morphology - that enables the encapsulation of inorganic compounds, or a planar texture - where anions and molecules can intercalate, the chemical analysis of graphite and graphitic materials is often confronted with the need to disintegrate the carbon matrix to quantify target elements, most often metals. However, the resilience of the sp2-hybridized carbon lattice to chemical attacks is an obstacle to its facile solubilization, a necessary step to perform some of the most common elemental analysis measurements. Over the years, a range of alternative approaches have sprung out to address this issue such as the combustion of the carbon matrix followed by the acid dissolution of its ash product. Unfortunately, none of these represents a viable method that can be applied to batteries, in great part because of the different components that make up the carbon-based electrodes. In this dissertation, a new protocol has been developed to digest graphitic materials aiming to access their elemental composition in bulk scale. The approach is based on the use of molten alkaline salts to promote the oxidation of the carbon lattice and leach out metals into a dilute acid solution. As a model sample, given the existence of standards with a matching matrix, single-walled carbon nanotubes were examined. After being subjected to the alkaline oxidation (a.k.a. fusion), they were solubilized and analyzed with Inductively Coupled Plasma-Optical Emission Spectroscopy, a widely popular tool for elemental analysis of metals. Structural analysis ensued to understand the interaction of the molten salts with the nanotubes. After evaluating the applicability of the protocol to other carbons, a more complex system was investigated, namely the carbon-based anode of an intercalation-type potassium ion battery. In this process, a direct way to quantify the mass of the alkali metal was discovered, one which makes use of complementary chemical and structural analytical tools.
36

From a sailing convey to a docked brewery : elucidating layers of time and adaptability using the SS nomadic as ideal archetype and Robinson dry dock as host

Meyer, Armand Anton January 2016 (has links)
Countless centuries has sailed by since humanity first discovered the method of travelling across the far stretched oceans that divided undiscovered continents. As noted by Le Corbusier, these liners were deemed being an engineering feat of the twentieth century, as their design resembled an epitome of indulgence and hospitality. As the average lifespan of a commercial liner is 25 years, the shipping industry is reaching a pinnacle point in time where countless ships will be decommissioned. As these vessels were originally built to be both functional and appealing in nature, why have them reduced to hazardous scrap metal, when they can be repurposed on land? In order to physically implement such an interior endeavor, both a decommissioned ship ideal in typology and status, along with a suited location for docking was to be advocated. The selection of Robinson Dry Dock as host and the SS Nomadic as habitant allowed for the spatial intervention of a retail-orientated and recreational facility to be envisioned. As opposed to the mere institution of a heritage approach, the appendage of a new layer is proposed that will allow for past recollection and future addition thereon - thus a palimpsest of design in terms of programmatic response and actual materiality. As the spatial and structural formation of vessels primarily rely on steel and the construction of a dock on concrete, these materials will be probed comprehensively in standings of their vulnerability to degradation. Proposed avenues of material investigation permits corrosion protection, historic decay preservation and intentional oxidation techniques that can conceivably ground potential design implementations. The decisive spatial outcome aims to endorse the idea that corrosion can act as a tool of architectural beautification, rather than a mere entity of intimidation. This idea is heightened by the insertion of a microbrewery that factually exemplifies the splendor of aging. Rather than promoting slavish alternative shipbreaking approaches and mere demolition practices, layered architectural alteration, as outlined by Fred Scott in his book, On Altering Architecture, will allow for the creation of a spatial intervention that is honest, nonintrusive and profound. / Ontelbare eeue het verby geseil sedert die mensdom 'n reismetode ontwikkel het wat hul in staat sou stel om uitgestrekte oseane, wat onontdekte kontinente verdeel, te verken. Soos opgeteken deur Le Corbusier, was hierdie lynbote beskou as 'n kordaatstuk vir ingenieurswese in die 20ste eeu, aangesien die ontwerp daarvan getuig van toegeeflikheid en gasvryheid. Omdat die gemiddelde leeftyd van 'n kommersi?le boot 25 jaar is, het die skeepindustrie 'n punt bereik waar heelwat skepe onaktief verklaar is. As hierdie werktuie oorspronklik bedoel was om funksioneel sowel as aantreklik van aard te wees, waarom dit dan reduseer tot 'n hoop skrootmetaal as dit vir 'n ander doel op land aangewend kan word? Ten einde so 'n poging te implementeer, moes 'n onaktiewe boot, tesame met 'n gepaste ligging vir die dok daarvan, voorgestel word. Die keuse van Robinson Droogdok as gasheer en die SS Nomadic as inwoner, laat ruimte vir 'n omgewings-vriendelike produk waarin die moontlikheid van kleinhandel en fasiliteite vir vermaak, voorkeur geniet. Teenoor die blote ingesteldheid van 'n erfenis-aanslag, is die byvoeging van 'n nuwe laag voorgestel, wat ruimte laat vir dit wat in die verlede gevestig is, sowel as toekomstige byvoeging ? dus 'n palimpses van ontwerp in terme van 'n programmatiese oplossing en materialiteit. Soos wat die ruimtelike en struktuele formasie van werktuie hoofsaaklik afhanklik is van staal en die konstruksie van 'n dok uit beton, sal hierdie materiale deeglik en omvattend ondersoek word in terme van hul kwesbaarheid wat degradering betref. Voorgestelde maniere om hierdie materiale te ondersoek en te toets, sal beskerming teen roes, asook historiese verval en doelbewuste oksidasie-tegnieke insluit, wat moontlik die grondslag kan l? vir potensi?le ontwerp implementering. Die uitkoms kan die idee bevorder dat verval en agteruitgang kan bydra tot argitektuele verfraaiing, eerder as om 'n blote entiteit vir intimidasie te wees. Hierdie idee word verder bevorder deur die 'n mikro-brouery by te voeg, wat die glorie van oudword beklemtoon. Eerder as om skeepsloping en blote vernietiging voor te staan, sal argitektuele verandering, soos uiteen gesit deur Fred Scott in sy boek, On Altering Architecture, die skep van 'n ruimtelike ingryping toelaat wat eerlik, nie-opdringerig en grondig sal wees. / Mini Dissertation (MInt (Prof))--University of Pretoria, 2016. / Architecture / MInt (Prof) / Unrestricted
37

Možnosti ovlivnění odpovědi buněk přirozené imunity na gliadin / The possibilities to influence the response of innate immune cells to gliadin

Drašarová, Hana January 2010 (has links)
Gluten sensitive entheropathy - celiac disease is a lifelong, genetically predisposed, immunologically mediated susceptibility to dietary wheat gluten, most frequently demonstrated by small-bowel damage and malabsorption syndrome. Strict adherence to gluten-free diet is the sole rational therapy of the disease. One of the possible therapeutic strategy for the treating of celiac disease is to utilize the synthetic polymer P(HEMA-co-SS). This polymer is capable specifically bound gliadin in gastrointestinal tract and by this way to neutralize the damaging effect of this alimentary protein on mucosa of small intestine in celiac patients. The in vitro study on human PBMC and specimens of small intestinal biopsies of celiac patients in our laboratory demonstrated that putative therapeutic ability of P(HEMA-co-SS) is substantially influenced by degree of proteolytic processing of gliadin and P(HEMA- co-SS) and also by different timing of per os administration of both components in organism. Another putative adjuvant therapy of celiac disease is employing of the beneficial probiotic bacterial strains. Our experiments were based on the findings of Prof. Y Sánz and her group demonstrating the significant differences in the composition of bacterial microflora in patients with active form of celiac disease,...
38

Computerized Oral Proficiency Test for Japanese: Measuring L2 Speaking Ability with ASR Technology

Matsushita, Hitokazu 08 July 2011 (has links) (PDF)
Developing a time- and cost-efficient method for second language (L2) oral proficiency measurement is one of the research topics that has attracted much attention in recent decades. The purpose of this study is to develop a computerized oral testing system for L2 Japanese using automatic speech recognition (ASR) technology. Two testing methods called elicited imitation (EI) and simulated speech (SS) are proposed to quantify L2 accuracy and fluency via ASR processing. This study also suggests systematic EI item creation leveraging corpus technology and discusses the effectiveness of the test items created through analyses of item difficulty. Further, refinement of the EI grading system is described through a series of statistical investigations. For SS, this study reports the five most influential L2 fluency features identified through machine learning and proposes a method to yield individual SS scores with these features based on previous studies. Lastly, several methods to combine the EI and SS scores are presented to estimate L2 oral proficiency of Japanese.
39

Bandwidth Efficient Reduced-Complexity MT-DS-SS via Reduced Subcarrier Frequency Spacing

Sen, Indranil 29 July 2004 (has links)
No description available.
40

Performance of Disparate-Bandwidth DS-SS Systems in Spectral Overlay Ad Hoc Networks

Alhashim, Najeeb S. 05 August 2009 (has links)
No description available.

Page generated in 0.033 seconds