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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.
201

L'or monnayé dans le Nord de la Gaule : recherches sur les monnaies d'or frappées dans le Nord de la Gaule entre le IIIe et 1er siècle avant notre ère / Gold Coinage in Northern Gaul : research on the production of gold coins in Northern Gaul, 3rd-1st centuries BC

Sillon, Charlotte 15 December 2014 (has links)
Cette étude est consacrée aux monnayages d'or frappés dans le Nord de la Gaule. Ce territoire, que Jules César nomme, le premier, "Gaule Belgique", s'étend entre la Seine et le Rhin. Les études numismatiques soulignent généralement les spécificités de cet espace, qui s'expriment particulièrement à travers l'importance de la frappe des monnaies d'or et leur typologie caractéristique. Il s'agit d'un phénomène majeur à l'échelle de la Gaule, que l'on cherche à appréhender depuis son apparition, au IIIe siècle avant notre ère, jusqu'à son terme au début de l'époque romaine.Afin de mener une réflexion sur les pratiques monétaires de cette région, nous proposons une nouvelle synthèse de l'histoire des monnaies d'or dans le Nord de la Gaule. Celle-ci passe par un réexamen des classements typologiques et des études métrologiques, ainsi que par l'élaboration de nouvelles cartes de répartition basées sur les trouvailles monétaires les plus récentes.L'approche interdisciplinaires développée dans le cadre de ce travail se traduit également par le recours aux analyses élémentaires, effectuées sur un corpus de 571 monnaies, afin d'étudier la composition de l'ensemble des émissions du Nord de la Gaule, reflets des différentes politiques monétaires et des stratégies d'approvisionnement en or au fil du temps que l'on cherche à étudier.Ainsi, l'étude typologique, métrologique et analytique des monnaies d'or du Nord de la Gaule permet d'esquisser les dynamiques monétaires mises en oeuvre au sein de cet espace. / This study deals with gold coinages struck in Northern Gaul. This territory, first referred to as "Belgic Gaul" in Caesar's writing, is located between the Seine and the Rhine. Specialists in ancient numismatics usually stress out various specific features displayed in this region, such as the unusually large amounts of gold coins which were issued there, as well as their peculiar iconography. This work investigates the implications underlying this important episode in Gaul's monetary history, from its emergence during the 3rd century BC to its end at the beginning of the Roman period.In order to enhance our knowledge about monetary uses and history in Northern Gaul, a comprehensive account is thus proposed, which combines renewed typological and metrological studies with distribution maps, based on the most recent data available at this point.Besides, our interdisciplinary approach involves elementary analysis performed on a sample of 571 gold coins. The aim is to characterize trends in the composition of all gold issues stuck in Northern Gaul, so as to identify chronological and regional patterns in monetary policies. By doing so, it thus becomes possible to stress out a distinctive set of strategies used by local authorities in order to control monetary production and to secure gold supplies through time. By combining iconographic, metrological and analytical studies, a new picture eventually emerges as regards dynamics in coin production and uses in Northern Gaul.
202

An investigation of some properties of Shredder Fines and an element analysis of its ash to find new ways of dealing with this waste / En undersökning av vissa egenskaper hos fragmenteringsrester och en elementanalys av dess aska för att hitta nya sätt att hantera detta avfall

Naidoo, Adeel January 2020 (has links)
Shredder fines are the materials with a particle size of less than 10 mm resulting from the shredding of vehicles and complex metal scrap from industries and municipalities. This waste is currently used as landfill construction material, but Stena Recycling wanted to know whether the bottom ash from the combustion of this waste could be useful to the cement industry, and whether it would be feasible to extract Cu and Zn from this ash. To determine this the shredder fines were combusted, and the generated bottom ash underwent chemical fractionation. The leachates from this were processed using MP-AES to obtain an elemental analysis of the ash. The uncombusted shredder fines had its moisture content and calorific value determined. The shredder fines had a moisture content of approximately 11%wt. Due to the heterogeneity of the shredder fines the calorific values varied significantly across the tested samples. The average value was 7.8 MJ/kg. The chemical fractionation showed that the elements in the ash are mostly insoluble in water and ammonium acetate, as the majority remained in the solid residue. This indicates that the ash is inert, and not susceptible to heavy metal leaching. The elemental analysis showed that there is a significant amount of Fe in the ash, with reasonable amounts of Cu and Zn. This project concluded that without additional processing the ash would not be suitable for the cement industry, and that there is potential for the recovery of Cu and Zn from the ash.
203

Využití analytických technik a chemometrie k autentifikaci vín / Application of analytical techniques and chemometry for authentification of wine

Pořízka, Jaromír January 2015 (has links)
This PhD. thesis is focused on application of different analytical techniques for determination of elemental composition of Moravian wine combined with analysis of selected polyphenol compounds. Two spectrometric techniques were used for elemental analysis of wine – Mass spectrometry and Optical emission spectrometry with inductively coupled plasma (ICP-MS and ICP-OES). Analysis of organic constituents of wine was evaluated by High performance liquid chromatograph with diode array detector (HPLC-DAD). Data from analysis of wine were used for construction of mathematical models for determining geographical origin of wine and for determining type of varietal wine. Data handling was performed by usage of multivariate statistical methods (cluster analysis, principal component analysis and canonical discriminant analysis). For the discrimination of wine by the geographical origin, two separate models for white and red wine were constructed. Effectiveness of discrimination of Moravian wine (with knowledge about origin) into 4 wine regions was 100 % successful for white wine and 96,43 % for red wine samples. Those models were used for cross validation test of unknown samples with result 95 % successfully classified samples of white wine and 82,15% of red wine. Besides that, mathematical model for discrimination and classification of varietal wine was made. Müller Thurgau, Riesling and Gruner Veltliner were discriminated by the usage of 8 elemental parameters. Discrimination success rate of known samples was evaluated by canonical discriminant analysis with 95,83% of correctly classified known samples and 70,83% of correctly classified unknown varietal wine (cross validation test). In addition to these part of research, impact of different grape production systems on elemental composition of wine and Vitis Vinifera was studied. The core of the study was to find the connections between the type of agriculture and chemical properties of wine and Vitis Vinifera. Two agriculture systems were assessed – Organic agriculture and Integrated pest management. . Results of this study showed that quantity and manner of pesticide application is very important factor affecting the final elemental composition of the grapevine and wine, especially the content of copper, zinc and manganese. That knowledge can be used in the future for creation of classification model of wine according to grape production system. For comparison of radical scavenging activity, electron paramagnetic resonance spectroscopy (EPR) with DPPH method was used. In the case of this study, the influence of vine growing under different farming systems on the total antioxidant activity of wine was found to be insignificant.
204

Ionenstrahluntersuchungen am Gelenkknorpel: Energiedispersive Röntgenspektrometrie, Rückstreuspektrometrie und Transmissionsionenmikroskopie (PIXE, RBS, STIM)

Reinert, Tilo 20 November 2001 (has links)
Knorpel ist ein kompliziertes System aus einem kollagenen Netzwerk, gefüllt mit wasserbindenden Makromolekülen (Proteoglykanen) und darin eingebetteten Zellen. Störungen in den komplexen Wechselbeziehungen können zur Gefährdung der strukturellen Integrität des Knorpels führen. Die hochauflösende Magnetresonanztomographie (NMR-Mikroskopie) kann über die Analyse der Signalintensität interne Knorpelstrukturen darstellen (hypo- und hyperintense Zonen). Mit Hilfe ionenmikroskopischer Analysemethoden (PIXE, RBS, ERDA) wurden im Knorpel (femorale und tibiale Kondyle des Hausschweins) im Querschnitt die zweidimensionalen Verteilungen der Knorpelelemente (H, C, N, O, P, S, Cl, K und Ca) aufgenommen sowie die Konzentrationen in ausgewählten Zonen bestimmt. Ergänzend wurde mit STIM die Dichteverteilung im Knorpel untersucht. Es gelang auch mit STIM, erstmalig kollagene Fasern in ihrer, bis auf den Wasserentzug natürlichen, Umgebung im Knorpel und damit unverändert in ihrer Anordnung sichtbar zu machen (keine chemische Demaskierung nötig). Die Ergebnisse wurden mit NMR- und polarisationsmikroskopischen Untersuchungen verglichen und in ihrem Zusammenhang mit den histologischen Knorpelzonen diskutiert. In den NMR-hypointensen Zonen fanden sich eine erhöhte Chlorkonzentration und punktförmige Calciumanreicherungen. Diese Zonen waren (im gefriergetrockneten Zustand) durch eine, bis zu einem Faktor vier höhere Dichte gekennzeichnet, die im maximalen Gehalt der Matrixelemente, H, C, N, O, (höchste Kollagendichte) begründet liegt. Im tibialen Knorpel konnten in der NMR-hypointensen Zone radial verlaufende einzelne Kollagenfasern nachgewiesen werden. Im femoralen Knorpel wurden in dieser Zone keine Einzelfasern nachgewiesen. Es deutete sich eine tubuläre Anordnung der Kollagenfasern an. In der hypertrophen Zone zeigten sich hohe Konzentrationen an Phosphor (Zellorganellen), Schwefel (Proteoglykane), Kalium (alkalisches Milieu) und Calcium (Vorstufe der Kalzifizierung). Die Chlorkonzentration hatte dort ihr Minimum. In dieser Zone verlaufen die Kollagenfasern radial und münden senkrecht in den Kalkknorpel. In der Tangentialfaserschicht wurde eine erhöhte Konzentration an Calcium und Phosphor beobachtet (Einlagerung von Calciumphosphaten). In dieser Zone wurden tangential verlaufende Kollagenfasern und ihr Übergang zur stärkeren Vernetzung mit teilweise arkadenförmiger Überstruktur sichtbar gemacht. Zur genaueren Aufklärung der dreidimensionalen Anordnung der Kollagenen Strukturen wurden erste Experimente zur STIM-Tomographie durchgeführt.
205

Separace a prvkové složení želvušek a vířníků v kryokonitu na Svalbardu / Separation and Elemental Composition of Tardigrades and Rotifers from Cryoconite in Svalbard

Jaroměřská, Tereza January 2019 (has links)
For years considered pristine, glacial ecosystems are attracting more attention of biologists from various branches in last decades. Moreover, they are currently considered to be ecosystems forming the coldest biome on the Earth. The life on glaciers ranges from viruses and bacteria to highest consumers such as few groups of microinvertebrates. The most common are tardigrades (phylum Tardigrada) and rotifers (phylum Rotifera) which inhabit cryoconite holes on the glacial surface. Several studies highlight the importance of the role of these consumers. However, due to the dominance of prokaryotes on the glacial surface, these microinvertebrates are usually out of the major scope of most studies aiming at biological processes. The present study shows pioneering results on the isotopic composition of tardigrades and rotifers, which are the top consumers in cryoconite ecosystems, and is a foundation for the exploration of trophic pathways and interactions within cryoconite holes using elemental and stable isotopic analyses. It also presents information about the species composition of tardigrades and rotifers on different glaciers and in different parts of the ablation zone. We identified 5 species of tardigrades (Hypsibius sp., Hypsibius cf. dujardini, Pilatobius sp., Isohypsibius sp. and Cryoconicus...
206

Applications of Two-Dimensional Layered Materials in Interconnect Technology

Chun-Li Lo (9337943) 14 September 2020 (has links)
<p>Copper (Cu) has been used as the main conductor in interconnects due to its low resistivity. However, because of its high diffusivity, diffusion barriers/liners (tantalum nitride/tantalum; TaN/Ta) must be incorporated to surround Cu wires. Otherwise, Cu ions/atoms will drift/diffuse through the inter-metal dielectric (IMD) that separates two distinct interconnects, resulting in circuit shorting and chip failures. The scaling limit of conventional Cu diffusion barriers/liners has become the bottleneck for interconnect technology, which in turn limits the IC performance. The interconnect half-pitch size will reach ~20 nm in the coming sub-5 nm technology nodes. Meanwhile, the TaN/Ta (barrier/liner) bilayer stack has to be > 4 nm to ensure acceptable liner and diffusion barrier properties. Since TaN/Ta occupy a significant portion of the interconnect cross-section and they are much more resistive than Cu, the effective conductance of an ultra-scaled interconnect will be compromised by the thick bilayer. Therefore, two dimensional (2D) layered materials have been explored as diffusion barrier alternatives owing to their atomically thin body thicknesses. However, many of the proposed 2D barriers are prepared at too high temperatures to be compatible with the back-end-of-line (BEOL) technology. In addition, as important as the diffusion barrier properties, the liner properties of 2D materials must be evaluated, which has not yet been pursued. </p> The objective of the thesis is to develop a 2D barrier/liner that overcomes the issues mentioned. Therefore, we first visit various 2D layered materials to understand their fundamental capability as barrier candidates through theoretical calculations. Among the candidates, hexagonal-boron-nitride (h-BN) and molybdenum disulfide (MoS<sub>2</sub>) are selected for experimental studies. In addition to studying their fundamental properties to know their potential, we have also developed techniques that can realize low-temperature-grown 2D layered materials. Metal-organic chemical vapor deposition (MOCVD) is adopted for the synthesis of BEOL-compatible MoS<sub>2</sub>. The electrical test results demonstrate the promises of integrating 2D layered materials to the state-of-the-art interconnect technology. Furthermore, by considering not only diffusion barrier properties but also liner properties, we develop another 2D layered material, tantalum sulfide (TaS<sub>x</sub>), using plasma-enhanced chemical vapor deposition (PECVD). The TaS<sub>x</sub> is promising in both barrier and liner aspects and is BEOL-compatible. Therefore, we believed that the conventional TaN/Ta bilayer stack can be replaced with an ultra-thin TaS<sub>x</sub> layer to maximize the Cu volume for ultra-scaled interconnects and improve the performance. Furthermore, Since via resistance has become the bottleneck for overall interconnect performance, we study the vertical conduction of TaS<sub>x</sub>. Both the intrinsic and extrinsic properties of this material are investigated and engineering approaches to improve the vertical conduction are also tested. Finally, we explore the possibilities of benefiting from 2D materials in other applications and propose directions for future studies.
207

New ways to interact with devices to change the gaming experience

Jankowski, Kim January 2020 (has links)
Gaming experience refers to the players’ overall experience when playing agame. Both game and controller have an impact on it. This project exploreshow different element arrangements on a controller can affect the players’gaming experience. Four lo-fi prototypes were constructed and used to bothtest the reaction of players, but also to educate them into the possibleelements included in controllers. Participants were then invited to designtheir own controller while reflecting about aspects like embodiment,immersion, or latency. Throughout the whole process participants reportedabout their previous experiences with controllers through an interview. Theresearch showed that the elemental arrangements did in fact affect theplayers’ gaming experience but also that there is a cultural understanding ofgames and controllers that constrains the possibility of new designs. Theproject also explored the limitations of conducting research on distance, andreflects about how remote design can be conducted.
208

Multienergetic External-beam PIXE as a Means of Stydying the Surface Enrichment Effect in Coins

Perry, Scott Evans 09 July 2003 (has links) (PDF)
This thesis paper examines the feasibility of using external-beam PIXE to study the surface enrichment effect in metal artifacts. By varying the energy of the incident proton beam, we penetrated the artifact's surface to different levels and were able to produce a depth profile of the elemental composition of the sample. In this study, the sample set we chose to examine consisted of ancient and modern coins. This paper first describes the surface enrichment effect and theoretically how PIXE can be used to study it. It then details the construction of the components of the external-beam setup. Many of the refinements of the hardware and experimental methods are discussed. It recounts the means of calibration of the detector and analytical tools. Finally, an accounting of the research performed on several coins is set forth, along with data showing the effectiveness of PIXE in complementing other methods of elemental analysis. We found that PIXE revealed statistically significant differences in concentrations of modern coins at the two beam energies we used. Ancient coins did not have similarly significant discrepancies between the two beam energies. The modern coin data suggested depletion in copper in copper-silver and copper-gold alloys, which is consistent with predictions of the theory of the surface enrichment effect. We suggest that the ancient coins are so deeply corroded that the PIXE beam is unable to penetrate adequately to observe surface enrichment. Comparison of our PIXE data to XRF and SEM data suggest that the trends we observed in modern coins are verified by the other methods. We therefore assert that external-beam PIXE is an effective tool for studying the surface enrichment effect, though with the beam energies available at Brigham Young University, the study must be limited to fairly modern coins.
209

MERCURY DISTRIBUTIONS AND CYCLING IN THE NORTH ATLANTIC AND EASTERN TROPICAL PACIFIC OCEANS

Bowman, Katlin L. January 2014 (has links)
No description available.
210

CHARACTERIZATION OF BIOLOGICALLY IMPORTANT VOLATILE AND NON-VOLATILE MOLECULES VIA HETEROATOM DETERMINATION USING CHROMATOGRAPHY AND MASS SPECTROMETRY

SHAH, MONIKA 17 July 2006 (has links)
No description available.

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