No description available.

Thesis (doctoral)--Universität Bayreuth, 2004. / Title from title screen (viewed June 10, 2009). Includes bibliographical references (p. 529-541).

No description available.

Thesis (Ph. D.)--Eberhard Karls Universität Tübingen. / Reproduced from typewritten copy. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 172-182).

Thesis (M.A.)--University of West Florida, 2009. / Submitted to the Dept. of Anthropology. Title from title page of source document. Document formatted into pages; contains 250 pages. Includes bibliographical references.

Luxury goods, used in mediaeval long distance trade ca. AD 900-1250, found an important market among the Iron Age peoples of southern Africa. Indirect evidence of this trade can be seen in the form of archaeological collections of glass beads at sites throughout Africa and Southeast Asia. Thousands of beads have been found at Iron Age sites in the eastern Transvaal Lowveld and at inland sites along the Limpopo Valley and in Botswana. Similar looking types of beads, referred to as small seed beads, were also used in the Muslim mercantile networks and maritime trade in the Indian Ocean, and have been found at coeval sites throughout Southeast Asia, particularly at entrepot ports in India, eastern and western Malaysia and Thailand. At the commencement of the Iron Age occupation of southern African sites, glass beads of any kind were very rare. From ca. AD 900-1000, Islamic influences spread southward along the African east coast. This coincided with the marked increase of glass beads found in southern Africa. Their presence is direct evidence of foreign industry, external trade and contact. The beads are widely believed to have originated in India, and to have been distributed through Arab traders in the Indian Ocean. Exports would have included gold, possibly ivory, and other raw materials. Archaeology has much to contribute towards documenting these activities. The identity and location of the bead sources is important to an understanding of early contact and economic and political developments in southern Africa. The trade connection coincided with the beginning of a critical sequence of events in the cultural history of southern Africa, which culminated in the formation of an incipient state at Great Zimbabwe (AD 1250-1450) from precursors at Mapungubwe and related sites. This period corresponds in time with an important episode in Islamic history, when Muslims conquered Egypt and the Fatimids moved their capital eastwards, in AD 969, from Tunisia to al-Qahira (Cairo) next to the well-established cosmopolitan port entrepot of al- Fustat (now old Cairo). Texts, chronicles, glass weights, scribal notes and receipts confirm that it was already a successful industrial centre with a history of glass-making when the Fatimids gained control of Egypt. In this thesis I have addressed two aspects of research to investigate the trade networks associated with internal and foreign contact: (1) the manufacturing origins of the beads, and, (2) who brought them to southern Africa. Glass material from Egypt, Palestine, Syria and Southeast Asia was used for comparison, and as possible source material. Scientific techniques were used to confirm these operations. The beads were described, classified, and sampled selectively for physical and chemical analysis. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to determine the rare earth elements (REE) composition. The results show that a particular glass, used to make beads in Egypt, is the same as that used to make some of the beads found at sites in the northern and eastern Transvaal. They document the existence of a trade link with the Mediterranean via the Red Sea 1000 years ago. Until now, both the origin of this contact and the extent of indigenous responses were largely unknown. These findings cast a different light on maritime trade along the east coast of Africa from a millennium ago. Bibliography: pages 175-190.

Pavement markings are vital for safely navigating roadways. The nighttime visibility of pavement markings is enhanced by addition of retroreflective glass beads, most of which are made from recycled glass. Concern has been raised over the presence of heavy metals in glass beads used in pavement markings and their effect on human and environmental health. Based upon the potential risk associated with the presence of arsenic and lead in the glass beads, two Bills are currently being considered before the 112th Congress of the United States of America seeking to set a maximum permissible limit for the amount of arsenic and lead in glass beads used within pavement marking systems on domestic roadways. This study was designed to support legislative decision making by providing data necessary for risk assessment. The experiments carried out provide: an analysis of glass bead metal content and extractability; an evaluation of the relationship between arsenic content of the glass beads and their retroreflective performance; an evaluation of analytical methods used to measure the total bead metal content; and an analysis of samples of glass bead and soil mixture from a glass bead storage site used to determine site-specific metal concentrations in the soil media. Mean arsenic content, measured using the Pacific Northwest National Laboratory's KOH fusion digestion, in all the glass beads examined ranged from 11 ppm to 82 ppm, while mean lead content, measured using KOH fusion digestion, ranged from below quantification limit to 199 ppm. Total metal content measurements indicated a high amount of variability in the glass bead samples; most likely associated with the use of recycled glass feed during manufacturing. The relationship between the retroreflective performance and the arsenic content of the glass beads was analyzed and a weak but positive correlation was observed between the two factors. However, a more detailed study is required to evaluate the relationship between arsenic content and retroreflectivity. Different methods to evaluate the total metal content in glass beads were compared; it is recommended that any analytical method may be used, as long as the standard reference material is reproduced within the range of concentration expected in the glass beads. In the analysis of the field site samples of soil containing glass beads obtained from a glass bead storage and transfer facility, the mass content of beads in the soil varied from a mean of 19% to 78% depending on the location within the facility. However, a detailed analysis with larger number of samples must be performed to evaluate the effect of glass beads on the total arsenic content of the soil.

Applications of lead and strontium isotope analysis were made on archaeological materials from three different contexts in both the Old and New Worlds. These materials comprised pre-Hispanic glaze painted ceramics from Arizona, U.S.A., glass beads from late first millennium AD Igbo-Ukwu, Nigeria, and copper-based metals from early first millennium AD Kissi, Burkina Faso. All materials contain lead at major, minor, or trace concentrations, and lead isotope analysis was employed to determine a provenance for that lead. Strontium isotope analysis also was applied to glass beads from Igbo-Ukwu to determine provenance(s) for strontium found in the glass. Furthermore, application of elemental composition analysis was or had been employed on all samples for additional data comparisons within assemblages and with comparable archaeological materials.Results of these analyses determined, in most cases, regional provenance with high degrees of confidence for lead contained in the analyzed samples. Strontium and elemental composition analysis data also proved valuable in confirming the regional provenance of the raw glass used to produce the glass beads. Leads in the glaze paints from Arizona, which demonstrated a range of resources exploitation, were confidently restricted to a few regions for their procurement. Likewise leads in most glass beads from Igbo-Ukwu were confidently restricted to two main source regions, with a third strong contender also being identified. The elemental composition and strontium isotope data determined with confidence the production regions for the primary raw glasses used to make the glass beads. Finally, leads in copper-based metals from Burkina Faso also were restricted to a few regions, although some inconclusiveness in provenance determination was attributed to mixing of metals from difference sources.These results confirm the utility of heavy isotope analysis of archaeological materials for provenance determination. The combination of these data with elemental composition analyses further confirm the interpretive strength of combining independent but related sets of analytical data for exploring questions of archaeological provenance. With improvements in instrument technology and application in the past two decades, very high precision and high accuracy analyses can be made which eliminate some earlier concerns of heavy isotope applications in archaeology.

Orientador: Marisa Masumi Beppu / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-15T00:01:01Z (GMT). No. of bitstreams: 1 Albarelli_JulianaQueiroz_M.pdf: 12079656 bytes, checksum: 4883a6fcc74937bc5e4be6b917ed0747 (MD5) Previous issue date: 2009 / Resumo: A quitosana é um polímero natural muito estudado devido à sua boa capacidade adsorvente. A aplicação deste biopolímero para remoção de metais pesados tem sido estudada desde o início dos anos 1970 sendo que o número de trabalhos sobre este tema cresceu rapidamente desde então. No entanto, o uso da quitosana como adsorvente em maior escala enfrenta alguns obstáculos, devido à sua baixa resistência mecânica. Uma possível alternativa para melhorar aspectos mecânicos e que também contribui para uma melhor transferência de massa do adsorbato no adsorvente é a imobilização da quitosana em matrizes sólidas utilizando-se técnicas de recobrimento de partículas. Neste contexto, este trabalho visou investigar a imobilização da quitosana em substratos para a aplicação em sistemas de adsorção. Inicialmente foram testados como suporte para imobilização da quitosana vidro, polipropileno, borracha vulcanizada, porcelana e tecido de algodão. O substrato de vidro, utilizado na forma de esferas, apresentou melhor interação com a solução de recobrimento e características adequadas para aplicação em processos de adsorção. As esferas de vidro foram recobertas por diferentes métodos utilizando quitosana 2,5% (m/v) em solução de ácido acético 3% (v/v). O material recoberto foi utilizado em sistemas de adsorção em batelada e contínuo a fim de se analisar a capacidade de remoção de cobre pelo filme de quitosana. Dentre as diferentes técnicas de revestimento estudadas, o processo por "dip coating" obteve um revestimento homogêneo e apresentou boa aderência do filme ao substrato. A natureza da superfície a ser recoberta e a temperatura da solução de recobrimento foram variadas objetivando-se melhorar a fixação da camada de quitosana no suporte, sendo esta ultima variável a mais importante para as condições estudadas. As isotermas de adsorção indicaram um aumento na capacidade de adsorção com o aumento da temperatura na qual ocorre a adsorção. Os dados foram mais bem representados pela isoterma de Langmuir, indicando que o principal fenômeno de adsorção se assemelha a adsorção em monocamada. Observou-se que a capacidade máxima de adsorção encontrada em 25 º C foi semelhante a outros sistemas de adsorção de cobre utilizando quitosana relatados na literatura. Verificou-se um melhor ajuste para o modelo cinético de pseudo-segunda ordem, sugerindo que o fator limitante para a transferência de massa é a reação química. Os estudos de adsorção dinâmica usando as esferas recobertas em sistema de leito fixo demonstraram a possibilidade de seu uso com resultados promissores. / Abstract: Chitosan is a natural polymer largely studied because of its good adsorption capacity. The application of this biosorbent for heavy metal removal has been studied since early 1970s and the number of papers in this subject has grown quickly ever since. However, the use of this material in larger scale faces some barriers due to its low mechanical strength. A possible alternative to improve mechanical resistance and also enhance mass transfer is the immobilization of chitosan onto solid matrices using particle coating techniques. In this context, this study investigates the immobilization of chitosan onto solid supports and its application on adsorption systems. It was tested as support for chitosan immobilization glass, polypropylene, vulcanized rubber, porcelain and cotton. The glass support, used in bead form, has shown the best interaction with the coating solution and good characteristics for application in adsorption processes. Glass beads were coated by different methods using chitosan 2.5% w/v in acetic acid 3% v/v solution. The coated material was used in batch and continuous adsorption systems to analyze the copper removal capacity of the chitosan film. Among the different coating techniques studied, the dip coating procedure formed a homogeneous coating and presented an acceptable film adhesion to the substrate. Variables such as type of surface to be covered and temperature of the coating solution were analyzed on the fixation of the coated material on the substrate. The latter variable affected the most in the studied condition. Adsorption isotherms indicated an increase in the adsorption capacity along with the increase of adsorption temperature. The data were better fitted by Langmuir model, which indicates that the main phenomenon that occurred approaches to a monolayer-type adsorption. The maximum adsorption capacity was found at 25ºC and its value was similar to other copper adsorption systems reported in the literature. The mechanism of sorption showed a better fitting to the second order kinetic model, suggesting that the limiting factor to mass transfer is the chemical reaction. The dynamic adsorption studies using the coated beads in a fixed bed system demonstrated the possibility of its use with promising results. / Mestrado / Engenharia de Processos / Mestre em Engenharia Química

As illness becomes increasingly more common in the United States and across the globe, the need for better and faster medical treatment is greater than ever. The purpose of this work is to evaluate advanced polymers and polymer composites that will provide for increased fluid flow while maintaining outer dimensional, stiffness, and burst resistance characteristics when compared to a currently used material. A polymer configuration consisting of a proprietary formulation that has a durometer approximately 10% higher than the current material with an outer wall thickness of approximately .020" passed a series of tests involving tensile strength, stiffness, flexural fatigue resistance, vacuum lumen collapse resistance and hydraulic burst resistance. This material configuration passed the requirements for applicable test standards and had a tensile strength 13.4% less than the control group, was 52.7% stiffer, did not sustain any noticeable wear or defects during the flexural fatigue test, had a tensile strength 14.8% less that the control group during a post flex fatigue tensile test, did not burst when 150 psi was applied to it for 5 seconds, and is estimated to have a 43% higher flow rate capacity than the current material.