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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.
1

Lithic technologies of the Discovery Islands: materials, stone tool production, and communities of skilled practitioners

Abbott, Callum William Filan 26 April 2018 (has links)
This thesis explores the findings of a diachronic analysis of three lithic assemblages from Quadra Island, British Columbia. From this, insights flow about the genealogies of technological practice and communities of skilled practitioners who inhabited the study area throughout its deep history. I use qualitative and quantitative methods including macroscopic lithic analysis, thin section petrography, X-ray fluorescence spectrometry, and morphometrics to operationalize these theoretical foundations. This suite of complementary methods and theory weaves a narrative of technological change alongside simultaneous continuity for hundreds of generations of human life. I argue this is evidence of the dynamic, sophisticated, yet enduring knowledge and practice of the inhabitants of the Discovery Islands throughout their deep histories that persist in the present. / Graduate / 2019-04-16
2

Undersökning av titanföreningar för tillverkning av standarder vid användning av röntgenfluorescens / Study of Titanium Compounds Used in the Manufacturing of Standard Specimens for X-ray Fluorescence

Binning, Linda January 2011 (has links)
SECO Tools manufactures tool inserts for all types of metal cutting machining. (Ti,W)C is a common raw material used in the production. At arrival, the material (Ti,W)C is always analyzed. Titanium has previously been analysed with x-ray fluorescence spectrometry, but as the calibration has previously been performed with two different types of titanium (rutile and metallic titanium), the results has differed. Because of that, this thesis project has been devoted to analyze titanium, to find the best titanium compound for producing standards. The work has been performed using literature studies and many experiments in the laboratories at SECO Tools inFagersta,Sweden. This project has included about ten working weeks. In this report the analysis methods of x-ray fluorescence spectrometry and spectrophotometry is described, as the methods has been used in the experiments. A big problem that was discovered during this project was the big standard deviation of results for the method used for analysing titanium with x-ray fluorescence. Because of that, much time of this project has been devoted to experiments trying to reduce the standard deviation between the samples, as this is vital to performing a reliable calibration. A variety of experiments has been performed without reducing the standard deviation between the samples to below 0.2 % -units for the (Ti, W) C-samples.
3

Geoarchaeology of the Palaeolithic in the Aegean Basin, Greece: a deposit-centered approach and its implications for the study of hominin biogeography in the Pleistocene

Holcomb, Justin A. 09 November 2020 (has links)
This dissertation consists of three articles that develop and implement geoarchaeological approaches to the study of hominin biogeography in the Greek islands, a region that may have played a key role during the initial peopling of southeastern Europe in the Middle to Late Pleistocene (770 – 13 ka). The first article addresses the need to find Palaeolithic sites in the Greek islands by reviewing geoarchaeologically informed archaeological surveys that prioritize deposits – Pleistocene sediments and soils – on mainland Greece. I operationalize and implement a four-phase approach for future deposit-centered surveys in the islands. I conclude that future surveys should target geomorphic settings conducive to paleosol preservation, such as in near-shore coastal areas (e.g., uplifted hillslopes and actively eroding alluvial fans) marked by paleo-sea-level-indicators (sea notches, marine terraces, and aeolianites), as well as sediment depo-centers (e.g., internally drained basins) in non-coastal geomorphic settings. The second article develops and employs a multiscalar geoarchaeological approach for investigating and interpreting complex hillslope formation processes at the newly excavated Palaeolithic site of Stelida, located on the island of Naxos, Greece. Here, I integrate traditional geoarchaeological methods (lithostratigraphy, pedostratigraphy, allostratigraphy) with microarchaeological techniques, such as thin-section soil micromorphology and portable x-ray fluorescence spectroscopy (pXRF) to separate sediments and soils aiding in the construction of a stratigraphic framework for Stelida.The third article further develops the method of integrating pXRF and soil micromorphology applied at the site-specific scale. In this article, I developed an Exploratory Spatial Data Analysis (ESDA) method for visualizing geochemistry-facies relationships through the application of pXRF to a resin-impregnated block sample preserving an Archaic (seventh century BCE) ash midden (eschara) from the site of Kalopodi, Greece.This dissertation addresses a primary research effort in Greece’s Aegean Basin (Greek islands): the search for and study of Palaeolithic archaeology dating to Middle and Late Pleistocene. Geoarchaeologically informed research designs, such as deposit-centered surveys in open-air environments, can increase Palaeolithic site inventories for the region by focusing on finding geomorphic settings conducive to paleosol preservation. Moreover, the multi-scalar geoarchaeological approaches here, which integrate sedimentology, pedology, micromorphology, and geochemistry, provide an effective approach for the identification and compositional (mineralogic and geochemical) study of paleosols within those settings.
4

Sedimentation in a small lake, more complex than previously assumed. : Bathymetrical and geochemical sediment analyses in Kassjön (63°55´ N, 20°01´ E).

Gydemo Östbom, Viktor January 2017 (has links)
For studies using lake sediments as a medium, understanding factors governing sediment distribution and properties is crucial for making accurate interpretations and conclusions. General lake sedimentation theory is however mainly based on larger lakes and systems, potentially leading to biased sampling and data interpretation when applied on a smaller system. In a paper published in 2008, Rippey et al. evaluated the fit of some general sedimentation theories on element distribution in the sediments of Kassjön (63°55´ N, 20°01´ E), northern Sweden. This small boreal lake reoccurs in the scientific literature, largely from paleolimnological studies on varved sediments in the lake, making the understanding of its sediment properties highly relevant. As part of a wider geochemical study on the lake, this paper scrutinizes the findings of Rippey et al. (2008) by using updated bathymetry and geochemical analyses, to provide further insight on sedimentation in Kassjön. Element composition, analysed with X-ray fluorescence spectrometry, and dry weight was obtained from sediment samples at 40 sites. Depth at sampling sites, together with catchment morphometry and previous bathymetry, was used to improve the bathymetric understanding. Kassjön was found to have a less steep bathymetry than previously assumed, with distribution of sediment geochemistry and dry weight showing heterogeneity differing from that expected of general sedimentation theories only. These results indicate that previous findings on sedimentation in Kassjön might be too simplistic, and that small-lake sedimentation is influenced by factors not included in general sedimentation models. Caution is therefore advised when e.g. interpreting the environmental record in lake sediments.
5

Authenticity Of Roman Imperial Age Silver Coins Using Non-destructive Archaeometric Techniques

Aydin, Mahmut 01 March 2013 (has links) (PDF)
Imitation of archeological artifacts or replacing the authentic ones with fake replicates is a universal problem / it is particularly important in Turkey for historical metal objects. Traditionally used visual inspection methods alone are not sufficient for the solution of contemporary problems. In this study, chemical characterization has been used to determine the differences between the authentic and fake objects. The non-destructive analyses were carried out by Portable X-ray Fluorescence Spectrometry (P-XRF). Silver Roman Coins (27 B.C. to 244 A.D.) were the objects handled in this research. In particular the concentrations of Zr, Pt, Pb and Bi were used for differentiation / it has been observed that the concentrations have different trends in the authentic and fake silver coins. In authentic coins the average Pb concentration was found to be 0.77%, while this value was 0.055% for the fake ones. Bi could be determined in 86% of the authentic coins while it could not be detected in any fake coin. It has been generally observed that the silver and copper concentrations could not be utilized in authenticity tests. Another approach was the use of Line Scanning Electron Microscopy-Energy Dispersive X-Ray Fluorescence Spectrometry (LSEM-EDX). Using LSEM-EDX technique, it was observed that the concentration changes near the interface between the matrix and the copper-rich locations exhibits difference behaviors for the authentic and fake objects. This difference is originated by the fact that a newly formed copper amalgam contains copper-rich phases while with extended time concentration changes at interfaces become more gradual or not detectable. Pearson correlation was used in order to elucidate the relations between the element concentrations determined by P-XRF. In order to see whether the authentic and silver fake coins can form separate groups, dendograms have been constructed utilizing SPSS 16.0 software and Euclidian Square Distance method. It has been observed that the authentic and fake coins can be successfully grouped when the proper statistical choices are used. It has been observed that these groups have significant differences using t-test. The selected and used technology is proposed for use by museums and entities keeping archaeological collections in order to prevent forgeries.
6

Differentiation And Classification Of Counterfeit And Real Coins By Applying Statistical Methods

Tansel, Icten 01 June 2012 (has links) (PDF)
ABSTRACT DIFFERENTIATION AND CLASSIFICATION OF COUNTERFEIT AND REAL COINS BY APPLYING STATISTICAL METHODS Tansel, I&ccedil / ten M.Sc, Archaeometry Graduate Program Supervisor : Assist. Prof. Dr. Zeynep Isil Kalaylioglu Co-Supervisor : Prof. Dr. Sahinde Demirci June 2012, 105 pages In this study, forty coins which were obtained from Museum of Anatolian Civilizations (MAC) in Ankara were investigated. Some of those coins were real (twenty two coins) and the remaining ones (eighteen coins) were fake coins. Forty coins were Greek coins which were dated back to middle of the fifth century BCE and reign of Alexander the Great (323 &ndash / 336 BCE). The major aims of this study can be summarized as follow
7

Desenvolvimento de um simulador para espectrometria por fluorescência de raios X usando computação distribuída / Development of a X-ray fluorescence spectrometry simulator using distributed computing

Marcio Henrique dos Santos 30 March 2012 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / A Física das Radiações é um ramo da Física que está presente em diversas áreas de estudo e se relaciona ao conceito de espectrometria. Dentre as inúmeras técnicas espectrométricas existentes, destaca-se a espectrometria por fluorescência de raios X. Esta também possui uma gama de variações da qual pode-se dar ênfase a um determinado subconjunto de técnicas. A produção de fluorescência de raios X permite (em certos casos) a análise das propriedades físico-químicas de uma amostra específica, possibilitando a determinação de sua constituiçõa química e abrindo um leque de aplicações. Porém, o estudo experimental pode exigir uma grande carga de trabalho, tanto em termos do aparato físico quanto em relação conhecimento técnico. Assim, a técnica de simulação entra em cena como um caminho viável, entre a teoria e a experimentação. Através do método de Monte Carlo, que se utiliza da manipulação de números aleatórios, a simulação se mostra como uma espécie de alternativa ao trabalho experimental.Ela desenvolve este papel por meio de um processo de modelagem, dentro de um ambiente seguro e livre de riscos. E ainda pode contar com a computação de alto desempenho, de forma a otimizar todo o trabalho por meio da arquitetura distribuída. O objetivo central deste trabalho é a elaboração de um simulador computacional para análise e estudo de sistemas de fluorescência de raios X desenvolvido numa plataforma de computação distribuída de forma nativa com o intuito de gerar dados otimizados. Como resultados deste trabalho, mostra-se a viabilidade da construção do simulador através da linguagem CHARM++, uma linguagem baseada em C++ que incorpora rotinas para processamento distribuído, o valor da metodologia para a modelagem de sistemas e a aplicação desta na construção de um simulador para espectrometria por fluorescência de raios X. O simulador foi construído com a capacidade de reproduzir uma fonte de radiação eletromagnética, amostras complexas e um conjunto de detectores. A modelagem dos detectores incorpora a capacidade de geração de imagens baseadas nas contagens registradas. Para validação do simulador, comparou-se os resultados espectrométricos com os resultados gerados por outro simulador já validado: o MCNP. / Radiation Physics is a branch of Physics that is present in various studying areas and relates to the concept of spectrometry. Among the numerous existing spectrometry techniques, there is the X-ray fluorescence spectrometry. It also has a range of variations which can emphasize a particular subset of techniques. The production of X-ray fluorescence enables (in some cases) the analysis of physical and chemical properties of a given sample, allowing the determination of its chemical constitution and also a range of applications. However, the experimental analysis may require a large workload, both in terms of physical apparatus and in relation to technical knowledge. Thus, the simulation comes into play as a viable path between theory and experiment. Through the Monte Carlo method, which uses the manipulation of random numbers, the simulation is a kind of alternative to the experimental analysis. It develops this role by a modeling process, within a secure environment and risk free. And it can count on high performance computing in order to optimize all the work through the distributed architecture. The aim of this paper is the development of a computational simulator for analysis and studying of X-ray fluorescence systems developed on a communication platform distributed natively, in order to generate optimal data. As results, has been proved the viability of the simulator implementation through the CHARM++ language, a language based on C++ which incorporate procedures to distributed processing, the value of the methodology to system modelling e its application to build a simulator for X-ray fluorescence spectrometry. The simulator was built with the ability to reproduce a eletromagnetic radiation source, complex samples and a set of detectors. The modelling of the detectors embody the ability to yield images based on recorded counts. To validate the simulator, the results were compared with the results provided by other known simulator: MCNP.
8

Desenvolvimento de um simulador para espectrometria por fluorescência de raios X usando computação distribuída / Development of a X-ray fluorescence spectrometry simulator using distributed computing

Marcio Henrique dos Santos 30 March 2012 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / A Física das Radiações é um ramo da Física que está presente em diversas áreas de estudo e se relaciona ao conceito de espectrometria. Dentre as inúmeras técnicas espectrométricas existentes, destaca-se a espectrometria por fluorescência de raios X. Esta também possui uma gama de variações da qual pode-se dar ênfase a um determinado subconjunto de técnicas. A produção de fluorescência de raios X permite (em certos casos) a análise das propriedades físico-químicas de uma amostra específica, possibilitando a determinação de sua constituiçõa química e abrindo um leque de aplicações. Porém, o estudo experimental pode exigir uma grande carga de trabalho, tanto em termos do aparato físico quanto em relação conhecimento técnico. Assim, a técnica de simulação entra em cena como um caminho viável, entre a teoria e a experimentação. Através do método de Monte Carlo, que se utiliza da manipulação de números aleatórios, a simulação se mostra como uma espécie de alternativa ao trabalho experimental.Ela desenvolve este papel por meio de um processo de modelagem, dentro de um ambiente seguro e livre de riscos. E ainda pode contar com a computação de alto desempenho, de forma a otimizar todo o trabalho por meio da arquitetura distribuída. O objetivo central deste trabalho é a elaboração de um simulador computacional para análise e estudo de sistemas de fluorescência de raios X desenvolvido numa plataforma de computação distribuída de forma nativa com o intuito de gerar dados otimizados. Como resultados deste trabalho, mostra-se a viabilidade da construção do simulador através da linguagem CHARM++, uma linguagem baseada em C++ que incorpora rotinas para processamento distribuído, o valor da metodologia para a modelagem de sistemas e a aplicação desta na construção de um simulador para espectrometria por fluorescência de raios X. O simulador foi construído com a capacidade de reproduzir uma fonte de radiação eletromagnética, amostras complexas e um conjunto de detectores. A modelagem dos detectores incorpora a capacidade de geração de imagens baseadas nas contagens registradas. Para validação do simulador, comparou-se os resultados espectrométricos com os resultados gerados por outro simulador já validado: o MCNP. / Radiation Physics is a branch of Physics that is present in various studying areas and relates to the concept of spectrometry. Among the numerous existing spectrometry techniques, there is the X-ray fluorescence spectrometry. It also has a range of variations which can emphasize a particular subset of techniques. The production of X-ray fluorescence enables (in some cases) the analysis of physical and chemical properties of a given sample, allowing the determination of its chemical constitution and also a range of applications. However, the experimental analysis may require a large workload, both in terms of physical apparatus and in relation to technical knowledge. Thus, the simulation comes into play as a viable path between theory and experiment. Through the Monte Carlo method, which uses the manipulation of random numbers, the simulation is a kind of alternative to the experimental analysis. It develops this role by a modeling process, within a secure environment and risk free. And it can count on high performance computing in order to optimize all the work through the distributed architecture. The aim of this paper is the development of a computational simulator for analysis and studying of X-ray fluorescence systems developed on a communication platform distributed natively, in order to generate optimal data. As results, has been proved the viability of the simulator implementation through the CHARM++ language, a language based on C++ which incorporate procedures to distributed processing, the value of the methodology to system modelling e its application to build a simulator for X-ray fluorescence spectrometry. The simulator was built with the ability to reproduce a eletromagnetic radiation source, complex samples and a set of detectors. The modelling of the detectors embody the ability to yield images based on recorded counts. To validate the simulator, the results were compared with the results provided by other known simulator: MCNP.
9

Estabilidade de hematitas pedogênica e litogênica / Stability of de litogenic and pedogenic hematites

Prudente, Carolina Borges 08 May 2017 (has links)
Há, em ciência do solo, muita informação sobre a estabilidade de hematita e goethita pedogênicas. Entretanto, observa-se uma escassez de informação a respeito da estabilidade da hematita presente em arenitos vermelhos (litogênica). Neste estudo, buscou-se investigar esses dois tipos de hematita quanto à estabilidade ante a dissolução por um agente redutor. Utilizaram-se amostras de rochas areníticas de quatro formações e quatro amostras de Latossolo com caráter férrico derivadas de basalto de diferentes regiões do Brasil. As amostras de rochas areníticas foram moídas separando-se as frações silte + argila para análises mineralógicas. Inicialmente, foi feita a concentração dos óxidos de ferro para o preparo das lâminas, tendo em vista as análises mineralógicas por difração de raios x. Em seguida, foram realizadas quatro extrações sucessivas do ferro mediante dissolução por ação do redutor ditionito citrato bicarbonato de sódio (DCB), realizada na terra fina seca ao ar (TFSA). Paralelamente, procedeu-se à determinação do ferro total (Fet) pelo método do ataque sulfúrico e pela espectrometria de fluorescência de raios x. Os resultados indicam que a melhor definição dos picos de raios x para a hematita litogênica é uma característica que revela melhor cristalinidade e consequente maior resistência à redução (solubilização pelo DCB80) do que aquelas observadas na hematita pedogênica. Nos difratogramas de raios x, observou-se muito pouca variação na posição de reflexões da hematita nos dois ambientes, indicando proximidade estrutural. Os resultados obtidos pela espectrometria de fluorescência de raios x revelaram ser essa uma técnica auxiliar importante no estudo mineralógico. / Much information is available in soil science on the stability of pedogenic hematite and goethite, but not on the stability of litogenic hematite present in red sandstones. This study investigates the stability of these two types of hematite in the face of dissolution by a reducing agent. The study included sandstone rocks from four formations and four samples of ferric, basalt-derived Latosol from different regions in Brazil. The sandstone samples were ground and had their silt + clay fractions separated for mineralogical analysis. Initially, iron oxides were concentrated for slide preparation by using X-ray diffraction for mineralogical analyses. Then, four successive iron extractions were carried out through dissolution by using reducing agent sodium dithionite-citrate- bicarbonate (DCB) on thin air-dried earth. In addition, total iron (Fet) was measured by using sulfuric attack and X-ray fluorescence spectrometry. The results indicate that the best definition of X-ray peaks for lithogenic hematite is a characteristic that reveals better crystallinity and consequently greater resistance to reduction (solubilization by DCB80) than those observed in pedogenic hematite. In the X-ray diffractograms, very little variation was observed in the position of hematite reflections in both environments, indicating structural proximity. The results obtained by X-ray fluorescence spectrometry proved to be an important auxiliary technique in the mineralogical study. / Dissertação (Mestrado)
10

Low Power Total Reflection X-Ray Fluorescence Spectrometry / 低出力X線管による全反射蛍光X線分析法

Liu, Ying 24 September 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18591号 / 工博第3952号 / 新制||工||1607(附属図書館) / 31491 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 河合 潤, 教授 酒井 明, 教授 伊藤 秋男 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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