This research developed an on-line measurement systemfor determining the amount of fluorochemicals on carpet fibers using energy-dispersive X-ray fluorescence (EDXRF).This system is designed as a complementary tool to an existingchemical burn test certified by the American Association ofTextile Chemists and Colorists (AATCC), which is performed off-line on randomly selected carpet samples and time consuming.This research reviewed XRF principles and determined parameters that affect XRF spectra such as measurement time, measurement number, X-ray tube voltage, X-ray tube current, primary beam filter, and carpet characteristics. For this application, XRF calibrations must be performed for carpets of all styles and types. However, preparing actual carpet calibration samples is expensive. This research introduced a methodology to synthetically generate reference spectra using XRF spectra from standard fluorochemical stock solution samples and from base carpet samples for each carpet type to be tested. Thus, actual, physical standards are not required for each carpet type or style. This study showed that the synthetically generated XRF spectra alone were not always sufficient to guarantee the confidence interval required by the certified AATCC test. Thus, it is recommended that for on-line implementation, burn test results should be used to create a historical data base for each carpet type to reduce margin of error for calibrations generated from the synthetic spectra.

In the north of Sweden lots of the soil is naturally contaminated by acid sulfate. When soil gets in contact with oxygen an oxidation process begins which releases elements that may be harmful to the surroundings. When the Botniabanan was built, soil had to be transported from the railroad area to deposit sites. This study was made to investigate the suspicions a landowner had regarding if his estate had been contaminated sulphide soil soil during the building of the Botniabanan. To do that four pits were dug in the area where the soil had been deposited. Then the soil was analyzed to see the content of sulfate, iron, organic matters and water. When the results was compared to other studies it showed that the content of sulfate and organic matters was to low to classify the soil as an acid sulfate soil.

The objective of this thesis is to categorize carpet types according to their XRF spectra and verify if further classification of carpets is possible for use of an XRF analysis system in the carpet manufacturing line. This thesis consists of (1) implementing and studying effective algorithms for automated analysis of X-ray spectra, (2) comparing known algorithms for X-ray spectra analysis, and (3) implementing our own algorithm for classification of carpets spectra obtained for further fluorine online analysis of XRF inspected carpets. This research is intended for quick and accurate automated analysis of raw XRF spectra and matching analysis results to a database of XRF spectra of raw carpets. The research uses spectrum signal processing and spectrum analysis regarding efficacy of combined methods for XRF inspected carpets. X-Ray Fluorescence is a key technology for detection of chemical elements. Fluorine is a key element for carpet's quality. XRF has been chosen to be a potential candidate to measure fluorine since it is a versatile tool for low concentration element detection. Due to specific XRF background spectrum for each different carpet type, carpet samples may need specific calibrations for further computation of carpet fluorine concentration. Automating the detection of the carpet type is intended to help in automating the XRF calibration.

71f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-09T13:15:43Z No. of bitstreams: 1 dissertação ALETE_definitiva_110330.pdf: 1412727 bytes, checksum: c409be4d388a7ed5944c1d0866387a9d (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-04-19T14:50:36Z (GMT) No. of bitstreams: 1 dissertação ALETE_definitiva_110330.pdf: 1412727 bytes, checksum: c409be4d388a7ed5944c1d0866387a9d (MD5) / Made available in DSpace on 2013-04-19T14:50:36Z (GMT). No. of bitstreams: 1 dissertação ALETE_definitiva_110330.pdf: 1412727 bytes, checksum: c409be4d388a7ed5944c1d0866387a9d (MD5) Previous issue date: 2010 / CAPES / O objetivo principal do trabalho foi à utilização da espectrometria de fluorescência de raios X com energia dispersiva (EDXRF) para determinação de elementos essenciais, tais como P, Cu, Fe, Mn e Zn em amostras de arroz na forma de pastilhas como método alternativo, obtendo resultados com precisão e exatidão aceitáveis no controle de qualidade dos alimentos. A validação foi feita comparando os resultados obtidos pelo método proposto com valores certificados e com aqueles obtidos utilizando decomposição das amostras em forno de micro-ondas com cavidade e os digeridos foram usados para determinação dos analitos por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e espectrometria de massas com plasma indutivamente acoplado (ICP-MS). A precisão foi avaliada em termos da repetibilidade, sendo que foram preparadas onze pastilhas do material de referência certificado de farinha de arroz 1568a NIST e efetuadas três medições em cada pastilha obtendo-se estimativas do desvio padrão relativo inferiores a 5%. A exatidão foi verificada com o material de referência certificado (farinha de arroz 1568a NIST) e o t-teste pareado revelou que não havia diferença significativa entre os valores certificados e obtidos ao nível de confiança de 95%. Foram obtidos os seguintes limites de detecção (LODs): 0,037 g 100g-1 para P e 1,2; 3,9; 5,1 e 2,2 mg Kg-1 para Cu, Fe, Mn e Zn, respectivamente. O procedimento proposto foi aplicado para P, Mn e Zn e apresenta vantagens tais como a redução do tempo de análise e a eliminação da etapa de decomposição da amostra, porém apresenta a desvantagem dos maiores LODs. De modo geral, os resultados são novas informações sobre a composição mineral do arroz consumido na cidade de Salvador, Bahia, sendo úteis para formação de base de dados. / Salvador

abstract: It is well known that the overall performance of a solar cell is limited by the worst performing areas of the device. These areas are usually micro and nano-scale defects inhomogenously distributed throughout the material. Mitigating and/or engineering these effects is necessary to provide a path towards increasing the efficiency of state-of-the-art solar cells. The first big challenge is to identify the nature, origin and impact of such defects across length scales that span multiple orders of magnitude, and dimensions (time, temperature etc.). In this work, I present a framework based on correlative X-ray microscopy and big data analytics to identify micro and nanoscale defects and their impact on material properties in CuIn1-xGaxSe2 (CIGS) solar cells. Synchrotron based X-ray Fluorescence (XRF) and X-ray Beam Induced Current (XBIC) are used to study the effect that compositional variations, between grains and at grain boundaries, have on CIGS device properties. An experimental approach is presented to correcting XRF and XBIC quantification of CIGS thin film solar cells. When applying XRF and XBIC to study low and high gallium CIGS devices, it was determined that increased copper and gallium at grain boundaries leads to increased collection efficiency at grain boundaries in low gallium absorbers. However, composition variations were not correlated with changes in collection efficiency in high gallium absorbers, despite the decreased collection efficiency observed at grain boundaries. Understanding the nature and impact of these defects is only half the battle; controlling or mitigating their impact is the next challenge. This requires a thorough understanding of the origin of these defects and their kinetics. For such a study, a temperature and atmosphere controlled in situ stage was developed. The stage was utilized to study CIGS films during a rapid thermal growth process. Comparing composition variations across different acquisition times and growth temperatures required the implementation of machine learning techniques, including clustering and classification algorithms. From the analysis, copper was determined to segregate the faster than indium and gallium, and clustering techniques showed consistent elemental segregation into copper rich and copper poor regions. Ways to improve the current framework and new applications are also discussed. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018

The focus of this study is to detect any similarities – or lack thereof – between the alloys of different types of oval brooches from the later Iron Age in Scandinavia. The study is furthermore concerned with how the alloys and the typologies can be mutually complimentary to one another in regards to dating or determining the age of specific oval brooches. For this purpose X-ray fluorescence (pXRF) was used on five different items deriving from Birka, Vendel and one of unknown context. The results indicate continuity with earlier studies regarding copper alloys with contents of zinc, and that this study’s brass brooches may have been produced in this alloy for its gold-like appearance. A higher level of lead can be found in the younger brooches, therefore indicating that tortoise brooches of a later date may contain more lead than their earlier counterparts. Furthermore, the study shows that brass may be mistaken for gold, and it raises questions about the use of metal originating from native copper sources. This study is a part of the Birka Black Earth Harbour project. / The Birka Black Earth Harbour project

Si bien podemos creer que el estudio de objetos arqueológicos y artísticos es de carácter netamente estilístico o histórico, en realidad, una aproximación a ellos a través de la química puede brindar información importante también.  En un país como el nuestro, con un amplio patrimonio cultural, es mucho lo que un químico puede hacer para ayudar a conocer mejor estos objetos y a saber conservarlos. / Although we may think that studies of archaeological and artistic objects are mainly historical or stylistic, a chemical approach can also provide important information about them.  In a country like ours, with a vast cultural heritage, a chemist can do a lot to further our knowledge of these objects and to help in their conservation.

Geochemistry has been used to determine the provenance and diagenetic history of eolian sandstone deposits. However, the grain size, sorting, cementation, and detrital composition of eolian units can change along dune foreset laminae. The purpose of this study was to test for consistent trends of compositional change along dune foresets. Such trends could increase the quality of geochemical sampling of eolian sandstones and possibly aid in estimating the original height of ancient sand dunes. XRF data was gathered for both major and trace elements from the Pennsylvanian to Permian Weber Sandstone, Early Jurassic Navajo Sandstone, and modern Coral Pink Sand Dunes of southern Utah. Data was plotted using both 2-dimensional scatter plots and 3-dimensional principal components analysis (PCA) plots. The PCA plots proved to be the most informative and suggest that there are no consistent, statistically significant geochemical trends within or between the three units sampled. However, this study found that PCA was able to show significant geochemical differences between the three units sampled, even when they are all dominated by a single mineral (>90% quartz). The Weber Sandstone had the most varied composition, and dunes within the unit could be highly dissimilar to each other. The Navajo Sandstone had less overall geochemical variability than the Weber Sandstone, and individual dunes were similar to each other. The modern Coral Pink Sand Dunes had much less compositional variation than either of the other two units, and dunes in this unit were very similar to each other.

Analyzing climate changes by loess sediment deposits formed after the last glacial maximum gives us information about how the environment was dynamically before humans physically could record climate changes. Sampling and analyzing loess from different places in the world give us a more reliable view of when events and changes in climate took place. Loess is a last step eolian transported, fine grained sediment and can be a good record as a Quaternary climate archive (Muhs 2013; Stevens et al. 2020). Loess-paleosol sequences can be used as a relative record for climate change. The paleosols in the sequence corresponds to soil which can indicate warmer interglacial/interstadial periods when chemical weathering was active at site. Loess in these sequences reflects on cold and dry climate during glacial periods (Buggle et al. 2008; Muhs 2013). By analyzing geochemical composition of bulk-samples from chosen site one can get information about if paleosols or loess deposits are present at certain depths of profile. Also, if a glacial or interglacial period was present then (Buggle et al. 2011; Johansson 2017). In this study X-ray fluorescence Spectroscopy (XRF), will be used to analyze elemental composition of loess. This to see how soluble and mobile elements relate to immobile and non-soluble ones. This can indirectly tell how paleosols and loess are distributed over the site and if shifts attempt by depth. The samples of loess in this study were taken from north-western France at a site called Primel-Tregastel. Soil weathering indexes will be used in this study to calculate weathering intensities for deposit. Na/Al-based indices called CIA, CIW, CPA, PIA, Index B and Sr-based ratios Ba/Sr and Rb/Sr was used (Buggle et al. 2011). The purpose of the study is to see if weathering has been active at site. And if, to reconstruct at which depths and to make a paleoclimatic interpretation of the site. Na/Al-based indices CIA, CIW, CPA, PIA and Index B shows indications of active weathering at site. Sr-based ratios Ba/Sr and Rb/Sr do also show same indications but with more dramatically variations. The content of mobile and immobile elements does also follow the principle that when mobile elements decrease in percentage, immobile elements get enriched in bulk-sample. The trends shown are a long time of cold climate due to low weathering intensities followed by one warmer and more humid period. Increasing weathering intensities, indicating an interglacial/interstadial period happens as a first development. Continuously a decrease happens in weathering intensity which would indicate a start of a colder period. Topmost layer has been improved and re-worked by human activity and will be misleading to use in a geochemical analysis and paleoenvironmental interpretation. / Att analysera klimatförändringar genom lössjordar formade efter senaste glaciala maximumet ger oss information om hur miljön såg ut dynamiskt innan människan hade möjligheten att mäta klimatvariationer. Genom analys och provtagning av lössjordar från olika platser i världen ger oss en mer trovärdig bild över när händelser och förändringar i klimat skedde. Lössjord är ett slutligen vindtransporterad, finkornigt sediment som även fungerar bra som register för Kvartära klimatarkiv (Muhs 2013; Stevens et al. 2020). Loess-paleosol sekvenser kan användas som ett relativt register för klimatförändringar. Paleosolerna i sekvensen motsvarar jord som indikerar varmare interglaciala/interstadiala perioder när kemisk vittring kan ha varit aktiv. Lössavlagringar i sekvensen reflekterar kallare och torrare klimat under glaciala istider (Buggle et al. 2008; Muhs 2013). Genom att analysera geokemiskt innehåll av prover från lokal kan man få fram information om paleosoler eller lössavlagringar finns vid visst djup i profilen. Indirekt även om en glacial eller interglacial period pågick då (Buggle et al. 2011; Johansson 2017). I den här studien används X-ray fluorescens Spektroskopi (XRF) för att analysera geokemiskt innehåll av lössjord. Detta för att se hur lösliga och mobila element är relaterade till icke-mobila och icke-lösliga element. Det kan indirekt peka på hur paleosoler och löss är fördelat över en lokal och visa om skillnader finns vid olika djup. Proverna i denna studie är tagna från nord-västra Frankrike vid en lokal som heter Primel Trégastel. Jord vittrings index kommer att användas i studien för att beräkna vittringsintensiteter för avlagringen. Na/Al-baserade index som heter CIA, CIW, CPA, PIA och Index B och Sr-baserade förhållanden Ba/Sr och Rb/Sr kommer användas (Buggle et al. 2011). Syftet med studien är att se om vittring har skett vid lokalen. Och om vittring påvisas, kunna rekonstruera vid vilka djup och slutligen göra en paleoklimatisk tolkning över lokal. Na/Al-baserade index CIA, CIW, CPA, PIA och Index B visar indikationer av vittring som varit aktiv vid studerad lokal. Sr-baserade förhållanden Ba/Sr och Rb/Sr visar samma indikation men med mer dramatiska variationer. Innehållet av mobila och icke-mobila element följer även principen om att när mobila element minskar i procent så ökar dom icke-mobila elementen. Trenderna som visas är en lång tid av kallt klimat med låg vittringsintensitet som följs av en varmare och fuktigare period med högre vittringsintensitet. Utvecklingen av denna ökande vittringsintensitet indikerar en pågående interglacial/interstadial period. Fortsättningsvis sker en minskning i vittringsintensitet vilket påvisar en början av en kallare period. Det översta lagret i lokalen har bevisats blivit förändrat av mänsklig aktivitet och kan var missvisande i en geokemisk analys och paleoklimatologisk tolkning.

Fused glass beads as a sample preparation method for X-ray Fluorescence spectroscopy (XRF) were introduced in 1957 by Claisse; it soon became the preferred method to introduce oxide samples to the spectrometer, because heterogeneity, mineralogical and particle size effects are eliminated during the fusion process. Matrix effects are largely reduced by the resulting dilution. With the recent advances in XRF spectrometers, instruments with enhanced generator and temperature stability, improved sensitivity (even for light elements), and effective matrix correction software are available. Consequently, the largest proportion of analytical error results from the sample preparation step. Sampling error will always contribute the largest overall error but that is not the topic of this discussion. After more than 50 years of fused bead use in XRF analysis, certain matrices remain problematic. Although many fusion methods for chromite-, sulphide- and cassiterite-rich materials have been published, easily reproduced, routine methods for these still elude analytical chemists. Lengthy fusions at temperatures higher than 1100ºC are often prescribed for refractory materials and ores, and until recently one of the biggest challenges was a metal-bearing sample e.g. contained in slags or certain refractory materials. This study was conducted to identify and elucidate the reactions occurring in the formation of a lithium borate glass, but also between the lithium borate and oxides during glass formation. Different analytical techniques were used to investigate the reactions occurring during the fusion process based on theoretical glass-making principles. As a starting point, Thermo Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) were used jointly to evaluate the reactions occurring during the fusion of lithium borate glasses, and at a later stage, oxide/flux mixtures. When a different TGA instrument was used, Differential Scanning Calorimetry (DSC) was used in conjunction with the TGA. Observed reactions were modelled in a muffle furnace to produce identical material in larger quantities, and this material was then investigated using X-ray Powder Diffractometry (XRD), Raman Spectroscopy and Electron Microprobe Analysis (EPMA). The most enlightening result from the TGA/DSC results was the large mass loss above 1050 ºC. Literature often prescribes prolonged fusions at elevated temperatures for certain fusions, but it was proved beyond reasonable doubt that this practise causes volatilisation of the flux and leads to erroneous analytical results. The next analytical technique applied to the flux and flux/oxide samples was XRD. Where pre-fused fluxes were investigated, the XRD data served as confirmation of the glassy state of the pre-fused flux as a broad humpy scan indicative of an amorphous material was seen in stead of a diffractogram with sharp, well defined peaks. After heating to above the temperature of re-crystallisation, the phases present could be identified from the diffractogram. Provisional results using the in-situ, high temperature stage point towards the possibility of using this technique to great effect to investigate the presence of different phases formed at high temperatures. Flux-oxide mixtures were measured on the high temperature stage and after cooling a new phase was observed indicating that new phases formed during a fusion reaction. As the heating stage is slow-cooled, the chance of crystallisation in the glass is good, providing the possibility for investigating this formation of new phases at elevated temperatures further with a more suitable heating element that will contain the material. Raman spectroscopy was subsequently used to gain information about the bonds within the flux. Pure lithium tetraborate and lithium metaborate fluxes were analysed as well as flux oxide mixtures. The vibrations could not be predicted from first principles as band broadening occurs in glasses that makes theoretical predictions very difficult. The data obtained was compared to similar studies in literature and good agreement was found. In oxide-flux mixtures definite new bands were observed that was not part of the flux or oxide spectrum. EPMA results allowed calculation of the maximum solubilities of an oxide in a specific flux. It was done using Cr2O3 and ZrO2 and compared well with experimental values obtained from literature. The microscope images revealed some new insights into the theory of XRF fusions. It could clearly be seen that dissociation of the minerals in the sample occurred, thus proving that no mineralogical effects exist in a fused glass bead, and it could be observed that the flux oxide mixture devitrify when over saturated. / Dissertation (MSc)--University of Pretoria, 2010. / Chemistry / unrestricted