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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Caracterização paleoambiental dos carbonatos microbiais do membro crato, Formação Santana, aptiano-albiano da Bacia do Araripe

Bardola, Tatiana Pastro January 2015 (has links)
Este estudo apresenta os resultados de dados coletados em testemunhos de sondagem e afloramentos na sucessão aptiana-albiana da Bacia do Araripe, NE do Brasil. Carbonatos micríticos laminados se intercalam com rochas siliciclásticas, cujo índice de alteração química (CIA) é indicativo de um clima tipicamente árido a semi-árido. O Membro Crato foi formado sob regime hidrológico altamente variável, em uma laguna salina costeira sujeita a flutuações da profundidade da lâmina d´água, salinidade e grau de oxigenação. As condições ambientais estressantes favoreceram o desenvolvimento de extensos tapetes microbiais, responsáveis pela precipitação da maior parte dos carbonatos laminados. A origem microbial dos carbonatos é atestada por uma variedade de feições de esteiras microbiais, incluindo feições relativas ao crescimento (biolaminações, bioconstruções dômicas, padrões semelhantes a Kinneyia) e feições derivadas da destruição física das esteiras (estruturas “roll-up”, fissuras lineares incompletas, e fragmentos de esteiras oriundos da dessecação dos filmes microbiais). A presença de esteiras microbiais que recobriram os fósseis com EPS foi primordial na preservação extraordinária de tecidos moles. / This study presents the results on data collected in drill cores and outcrops in the Aptian-Albian succession in the Araripe Basin, NE Brazil. Laminated, micritic carbonates are interbedded with siliciclastic rocks that yielded CIA values typical of arid to semi-arid climate. The Crato Member was formed under a highly variable hydrologic regime (with fluctuating water depth, salinity and degree of oxygenation) in a coastal, saline lagoon. The stressful environmental conditions favored the development of extensive microbial mats, responsible for the precipitation of most laminated carbonates. The microbial origin of the carbonates is attested by a variety of microbial mat features, including growth-related features (biolaminations, domal buildups, patterns resembling Kinneyia) and features derived from physical mat destruction (roll-up structures, linear, incomplete fissures, and mat chips from desiccation of microbial films). The presence of microbial mats that covered the fossils with EPS was paramount for the extraordinary preservation of soft tissues.
42

Automatic Test Generation and Mutation Analysis using UPPAAL SMC

Larsson, Jonatan January 2017 (has links)
Software testing is an important process for ensuring the quality of the software. As the complexity of the software increases, traditional means of manual testing becomes increasingly more complex and time consuming. In most embedded systems, designing software with as few errors as possible is often critical. Resource usage is also of concern for proper behavior because of the very nature of embedded systems.  To design reliable and energy-efficient systems, methods are needed to detect hot points of consumption and correct them prior to deployment. To reduce testing effort, Model-based testing can be used which is one testing method that allows for automatic testing of model based systems. Model-based testing has not been investigated extensively for revealing resource usage anomalies in embedded systems. UPPAAL SMC is a statistical model checking tool which can be used to model the system’s resource usage. Currently UPPAAL SMC lacks the support for performing automatic test generation and test selection. In this thesis we provide this support with a framework for automatic test generation and test selection using mutation analysis, a method for minimizing the generated test suite while maximizing the fault coverage and a tool implementing the framework on top of the UPPAAL SMC tool. The thesis also evaluates the framework on a Brake by Wire industrial system. Our results show that we could for a Brake-by-wire system, simulated on a consumer processor with five mutants, in best case find a test case that achieved 100% mutation score within one minute and confidently identify at least one test case that achieved full mutation score within five minutes. The evaluation shows that this framework is applicable and relatively efficient on an industrial system for reducing continues resource usage target testing effort.
43

A Software Model for MATS Satellite Payload

Seth, Tejaswi January 2018 (has links)
This thesis presents the development of a software model that simulates a payload instrument onboard the MATS satellite. The goal of this model is to provide an understanding of how the instrument impacts the measured data. This model is important for error analysis and may help in correcting the measured data for systematic flaws in the instrument. The software will consist of 5 main modules as follows: Scene Generator, Optics Module,Stray Light Module, Charge-Coupled Device Module and Electronics Module. This thesis forms a basic foundation for the software by designing the CCD module and a part of the Optics module, and concludes the effects of both on the output of the system. It takes into account important mission defined procedures that ultimately aim to improve image quality, resolve vertical structures in different bandwidths and analyze noise effects on the measured data.
44

The use of palm leaf mats in soil erosion control

Paterson, D.G. (David Garry) January 2014 (has links)
Geotextiles have been used for many years in different parts of the world to promote soil conservation and to combat erosion. Such geotextiles may be synthetic (usually some form of plastic, sometimes with wire), or natural (usually some form of fibrous material). Work carried out at the University of Wolverhampton (UK) on the effectiveness of mats made from palm tree leaves sourced from the Gambia, West Africa led to a research project funded by the EU, which ran from October 2005 to February 2009, comprising the participation of four EU countries (UK, Belgium, Hungary and Lithuania) and six developing” countries (Brazil, Gambia, South Africa, Thailand, China and Vietnam). Research carried out in South Africa used mats made from the leaves of the Lala palm (Hyperhene coriacea). These mats are easy to make, flexible, durable and completely biodegradable. They cover approximately 40% of the soil surface, allowing space for vegetation to emerge, and add 1.3 kg of dry organic matter to each m2 of soil. Furthermore, they have a water retention capacity of 1.8 l kg-1 m-2, their N, K, S and P percentages are high, they have low sodium and aluminium values and a favourable C/N ratio. Firstly, trials were done on 20 South African soils and 10 mine tailings materials using a rainfall simulator. The soils varied considerably with respect to their textural, chemical and mineralogical properties as well as annual precipitation and geological origin. Erosion parameters varied greatly within, and to a much lesser extent between, the two different materials. Several significant correlations were obtained. Sediment load (SL) had the best correlation with kaolinite content and with fine sand content, while for runoff, the best correlation was with organic carbon content. When the samples were covered with palm mats values for final infiltration rate (FI) percentage stable aggregates (SA) and inter-rill erodibility (Ki) values were similar to those of bare materials and the amount of runoff was slightly higher. SL, however, was reduced by +65%. The next stage was to carry out a range of field trials, using runoff plots. Plots at four localities (Bergville, Ladybrand, Roodeplaat and Mabula) were used. Results showed that average runoff under the palm mats decreased by between 38% and 70%, compared to bare soil. Sediment concentration under the mats decreased by between 38% and 89%, using three combinations of slope, mat density and mesh size. Splash erosion at Roodeplaat decreased by between 62% and 68%, while re-vegetation at Ladybrand and Mabula increased by between 38% and 58%, with organic carbon content and topsoil accumulation also increasing under the mats. Various trials (using both the rainfall simulator and runoff plots) were carried out to evaluate the effects of reduced mat density and increased mesh size. Results from the other participating countries (25% to 95% reduction in runoff) confirm that there is much potential to use organic, bio-degradable, easy to manufacture geotextiles such as palm leaf mats, especially to combine employment opportunities with enhanced environmental protection in many susceptible areas of South Africa. / Thesis (PhD)--University of Pretoria, 2014. / gm2014 / Plant Production and Soil Science / unrestricted
45

Caractérisation phylogénétique et fonctionnelle de microbialites et de tapis microbiens / Phylogenetic and functional characterization of microbialites and microbial mats

Saghaï, Aurélien 08 December 2016 (has links)
Les tapis microbiens sont des communautés benthiques, calcifiées (i.e. microbialites) ou non, diverses à la fois phylogénétiquement et métaboliquement. Les tapis microbiens fossiles constituent les plus anciennes traces de vie sur Terre et leurs représentants modernes peuvent donc être utilisés pour comprendre le fonctionnement de ces écosystèmes anciens. J'ai étudié les communautés microbiennes (archées, bactéries et eucaryotes) de plusieurs microbialites (lac Alchichica, Mexique) et tapis microbiens (dans une mare du salar de Llamara, Chili) afin de caractériser finement leur structure phylogénétique et d'améliorer notre compréhension de leur fonctionnement. J'ai pour cela utilisé une approche combinant des outils moléculaires (métabarcoding, métagénomique) à des données environnementales (paramètres physico-chimiques de la colonne d'eau ou composition minérale des microbialites). Mon travail de thèse a permis d'affiner le modèle de formation des microbialites d'Alchichica, en montrant notamment que, en plus de la photosynthèse oxygénique cyanobactérienne, le potentiel à précipiter des carbonates de la photosynthèse eucaryote et, surtout, de la photosynthèse anoxygénique est important. Les communautés des tapis de Llamara étaient quant à elles caractérisées par la présence de nombreuses lignées d'archées et de bactéries très divergentes, dont certaines ont été identifiées pour la première fois dans ce travail. Nos analyses ont aussi souligné la diversité des organismes impliqués dans les cycles du soufre et de l'azote au sein de ces systèmes et permis d'identifier de potentielles interactions biotiques entre des lignées procaryotes dont l'écologie est peu connue. Enfin, nous avons mis en évidence que les paramètres environnementaux influencent fortement la composition des communautés associées à ces microbialites et à ces tapis microbiens. L'ensemble de ces résultats permet de mieux comprendre le fonctionnement de ces systèmes ainsi que les facteurs qui influencent leur structure phylogénétique et fonctionnelle. / Microbial mats are phylogenetically and functionally diverse benthic microbial communities, which can be sometimes calcified (i.e. microbialites). Fossil microbial mats constitute the oldest traces of life on Earth and their modern representatives are thus used as analogues of those primordial ecosystems to gain insights into their functioning. I have studied the microbial communities (archaea, bacteria and eukaryotes) of several microbialites (lake Alchichica, Mexico) and microbial mats (in a small pond in the salar de Llamara, Chile). The main objectives of my PhD were to finely characterize their phylogenetic structure and to improve our understanding of the functioning of these complex ecosystems. To do so, I have applied a multi-disciplinary approach combining molecular approaches (metabarcoding, metagenomics) to environmental data (physico-chemical parameters of the water column or mineral composition of the microbialites).The results presented in this thesis allowed refining our model of microbialite formation in Lake Alchichica. We showed that, in addition to cyanobacterial photosynthesis, both eukaryotic and, particularly, anoxygenic photosyntheses were potentially important to promote carbonate precipitation. Llamara mat communities were characterised by the presence of numerous novel archaeal and bacterial lineages, some of which were identified for the first time in this work. Our analyses have also highlighted the diversity of organisms involved in both sulphur and nitrogen cycles in these mats and identified potential biotic interactions between poorly known prokaryotic lineages. Finally, we showed that the composition of the microbial communities associated to these microbialites and microbial mats was strongly influenced by environmental parameters. Overall, these results represent a substantial contribution to our understanding of the ecology of these systems as well as of the factors that influence their phylogenetic and functional structures.
46

Methods of Processing Kenaf Chopped Strand Mats for Manufacturing Test Specimens and Composite Structures

Heil, Joshua W. 01 May 2015 (has links)
Bio-composites are increasing in demand due to governmental incentives across the globe for both environmental and human health reasons. The ideal bio-composite is renewable, recyclable, available, and non-toxic. To properly engineer bio-composite products, the physical properties of the fiber as well as fiber/matrix interactions must be known. The problem lies in the fact that many suitable natural fibers are not currently available in a material form that may be easily worked with. This research investigates methods to process raw kenaf (hibiscus cannabinus) on a scale that allows researchers to make more consistent samples for testing. Though kenaf is highlighted, these processing methods may be applied to any natural fiber. The raw fibers are processed into kenaf chopped strand mats (KCSM) by adapting basic paper-making techniques. KCSM exhibit paper-like qualities and mechanical properties and provide a material of uniform thickness for use in composite parts. Also presented are a basic understanding of natural fiber constituents and effects of mechanical and co-mechanical treatments on those constituents. To test KCSM, samples are made for the ASTM D3039 tensile testing and for testing in a dynamic material analyzer (DMA). Both mechanically and chemo-mechanically processed samples are made for the purpose of comparison. Also, I-beam bridges are built with KCSM to demonstrate how KCSM may be used to create a structure. This is spurred on by the annual SAMPE bridge competition that includes special categories for natural fiber beams. The lay-up procedure is shown in detail to provide a framework that future competitors may use to build quality I-beams for this competition. The properties obtained by using the KCSM are competitive with other reported properties for kenaf-based composites. A kenaf I-beam demonstrates a strength-to-weight ratio that is 65% of a berglass I-beam built to the same dimensions. Trade-os of using KCSM are the random 2d-fiber orientation and brittle failure, which are not usually desirable in composite components. The chemically treated samples indicate a higher degree of crystallinity but demonstrate inferior mechanical properties when compared to the untreated samples.
47

"Det händer saker som jag inte känner igen mig i." : En kvalitativ innehållsanalys av nyhetsrapporteringen om Mats Löfving och polishärvan.

Torlind, Evelina, Andersson, Linn January 2023 (has links)
Syftet med studien är att bidra med ökad kunskap om hur tryckta tidningar i sin nyhetsrapportering gör skillnad på sak och person vid stora nyhetshändelser som involverar offentliga personer. Målet är att kunna bidra med en bredare kunskap om hur mediedrev mot offentliga personer kan förstås utifrån tidningarnas gestaltning av dem och vad som kan uppfattas som etiska övertramp. Forskningsfrågorna som studien utgått från är “Hur har Aftonbladet och Expressen gestaltat Mats Löfving i tryckta nyhetsartiklar från det att han först misstänktes för tjänstefel fram till hans död?” samt “Vilka likheter och skillnader finns det mellan Aftonbladet och Expressen i rapporteringen om Mats Löfving?”. Metoden för studien är en språklig textanalys kombinerat med en kvalitativ innehållsanalys. Totalt har nio nyhetsartiklar analyserats. Teorierna som används är medielogik, gestaltningsteori samt offentliga- och privata sfärer. Resultatet av studien visar att Aftonbladet och Expressen har gestaltat Mats Löfving med negativa inslag, samt att det förekommer likheter och skillnader i respektive tidnings gestaltningar.
48

Experimental determination of heat transfer through metal foils and ceramic fiber mats during composite fabrication

Tkach, Suzanne G. January 1997 (has links)
No description available.
49

The Embodiment of the Unconscious, Hysteria, Surrealism, and Tanztheater

Krtolica, Marija January 2018 (has links)
The primary subject of this dissertation is mental illness and performance of the hysterical symptom as they were investigated by the Swedish choreographer Mats Ek (Giselle, 1982), Tanztheater (from 1975-1979), and Second Wave Feminism. Historically, the examination begins in the nineteenth century, with the staging of madness in the romantic ballet Giselle (1841), and medical showings at Salpêtrière (1870s). The historical sites point to the interweaving of medical and dance cultures, and to a tendency towards pathologization of idiosyncratic movement expression within nineteenth century discourses on heredity, degeneration, and female health. To historically probe the ways in which twentieth century concert dance commented on pathologization of femininity, female performative labor, and expressive movement, the examination extends to: the fin-de-siècle café-concert scene; psychoanalytic sessions of 1890s, in which dancing played a role in both diagnosis and treatment; Nijinsky’s dance modernism as seen in Le Sacre du Printemps (1913); the anti-psychiatry within the post-1st World War Surrealism, and the post-2nd World War psychologically inflected choreographies by Antony Tudor, Martha Graham, Donya Feuer and Paul Sanasardo. The performance sites are investigated in relationship to the concepts of the unconscious, trauma, hysteria, hystericization, symptom, and expression. The dissertation proposes that late nineteenth century hysteria gained emancipatory meanings in the theoretical work of twentieth century dance scholarship, feminism, cultural criticism, and Freudian-Lacanian psychoanalysis. On the side of practice, Tanztheater participated in reclaiming hysteria. The Rite of Spring (1975), Bluebeard (1977), Café Müller (1978), and Arien (1979) explored traumatic memory, and male/female relationships in context of the post-2nd World War consumerist culture. I examine Pina Bausch’s and Mats Ek’s choreographies in dialogue with the contemporary theory to show that dance spectatorship can bring about an understanding of how the residues of political and personal past shape the experiences of the present. / Dance
50

Insikter från satellitobservationer : Förståelse av aurorans komplexitet / Insights from satellite observations : Understanding of the complexity of aurora

Norell, Johan, Svensson, Emil January 2024 (has links)
Idag finns det omkring 5 000 operativa satelliter i omloppsbana runt jorden. Bland dessa finns MATS, DMSP-17/18 och Swarm-A/B/C. De tre satellitprogrammen ger olika data från jordens övre atmosfär där MATS bland annat observerar infraröd emission, DMSP mäter elektron- och jonnedfall från rymden och Swarm bland annat mäter variationer i jordens geomagnetiska fält. Dessa data ger möjlighet att analysera aurora. Aurora, även känt som polarsken, är ett fantastiskt ljusfenomen som kan urskiljas i olika färger och som har forskats på under flera decennier. Till följd av detta finns även möjligheten att göra gymnasieelever mer intresserade av rymden. När elever deltar i autentiskt lärande kan det bidra till ökat intresse inom naturvetenskap. Studien syftar till att undersöka auroraregionerna och jämföra data mellan MATS, DMSP och Swarm för att skapa en helhetsbild av fenomenet. Dessutom utvecklas ett lektionsmaterial som syftar till att öka intresset för rymden och fysik i allmänhet bland gymnasieelever. Metoden för den tekniska delen innefattade att finna konjunktioner mellan MATS och en annan satellit eftersom satelliterna ska ge data för samma fenomen. Under en konjunktion behövde banorna stämma överens samtidigt som satelliterna skulle ha tillgänglig data vid tidpunkten. För den pedagogiska delen har en enkätstudie använts för att samla in lärares åsikter om utveckling och utvärdering av lektionsmaterialet. Fem konjunktioner undersöktes och resultaten visade på en ökning av elektron och jonenergi samt flöde i auroraregioner. Ett fall visade en svag uppåtriktad ström som en potentiell förklaring till den ökade energin, vilket möjligtvis tillåter elektronerna att accelerera mot jorden och därav ökar flödet. Enkätstudien visade att det fanns ett intresse för ett lektionsmaterial. Fokus skulle ligga på att skapa ett autentiskt material där eleverna fick en genomgång om hur polarsken uppstår och därefter diskutera frågor kopplade till materialet. Utvärderingen visade att syftet och lärandemålen för lektionen hade uppfyllts. Eleverna deltog aktivt i diskussioner, ställde följdfrågor och ansågs vara intresserade av materialet. / Today there are around 5 000 operative satellites currently in orbit. MATS,DMSP-17/18 and Swarm-A/B/C are just a few among them. These three satellite programs produce different data from Earth’s upper atmosphere. MATS observe infrared emission, DMSP measure electron- and ion precipitation and Swarm measure variations in Earth’s geomagnetic field. This data provides the opportunity to analyze aurora. Aurora, also known as polar lights, is a fantasticlight phenomenon that can be observed in different colors and has been researched for decades. As a result, there is also a possibility to increase the interest among high school students to learn about space. A contribution to their interest can be seen when the students are allowed to participate in authentic learning.The study aimed to investigate aurora regions and compare data between MATS, DMSP and Swarm in order to create a comprehensive picture of the phenomenon. Additionally, an educational material was developed with the aim of increasing interest in space and physics in general among high school students. The methodology for the technical part consisted of finding conjunctions between MATS and one other satellite. This was because of the fact that the satellites were required to give data from the same phenomenon. During a conjunction the orbits of the satellites had to correspond and the satellites also needed to have available data from the time period. A survey study was conducted for the pedagogical part in order to collect opinions from teachers about the development and evaluation of the educational material. Five conjunctions were examined, and the results indicated an increase in electron and ion energy as well as flux in auroral regions. One case showed a weak upward current as a potential explanation for the increase in energy, possibly allowing electrons to accelerate towards the Earth and thus increasing the flux. The survey study showed that there was an interest in the educational material. The focus would be to create an authentic material where students were given an overview of how aurora occur followed by questions to discuss related to the material. The evaluation showed that the purpose and learning objectives of the lesson had been fulfilled. Students actively participated in discussions, asked follow-up questions and were considered to be interested in the material.

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