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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

Petrology of permian coal, Vasse Shelf, Perth Basin, Western Australia

Santoso, Binarko January 1994 (has links)
The Early Permian coal samples for the study were obtained from the Vasse Shelf, southern Perth Basin, located approximately 200 km south- west of Perth. The selected coal samples for the study were also obtained from the Premier Sub-basin of the Collie Basin and the Irwin Sub-basin of the Perth Basin. The Early Permian coal measures are described as the Sue Coal Measures from the Vasse Shelf, the Ewington Coal Measures from the Premier Sub-basin and the coal measures from the Irwin sub-basin are described as the Irwin River Coal Measures.The Vasse Shelf coal is finely banded and the dominant lithotypes are dull and dull banded types, followed by bright banded and banded types, with minor bright types. The variation of dull and bright lithotypes represents fluctuating conditions of water table level during the growth of peat in the swamp. The maceral composition of the coal is predominantly composed of inertinite, followed by vitrinite and minor exinite and mineral matter. The coal is characterized by very low to medium semifusinite ratio and medium to high vitrinite content, supporting the deposition in anaerobic wet conditions with some degree of oxidation. The coal is classified as sub- bituminous to high volatile bituminous of the Australian classification. In terms of microlithotype group, the predominance of inertite over vitrite suggests the coal was formed under drier conditions with high degree of oxidation during its deposition. On the basis of the interpretations of lithotypes, macerals, microlithotypes and trace elements, the depositional environment of the coal is braided and meandering deltaic-river system without any brackish or marine influence.The maceral composition of the Collie coal predominantly consists of inertinite and vitrinite, with low exinite and mineral matter. The very low to low semifusinite ratio and low to medium vitrinite content of ++ / the coal indicate that the coal was formed under aerobic dry to wet conditions with some degree of oxidation. The coal is categorized as sub-bituminous according to the Australian classification. The domination of inertite and durite over vitrite and clarite contents in the coal reflects the deposition under drier conditions with fluctuations in the water table. On the basis of the interpretations of macerals, microlithotypes and trace elements distribution, the depositional environment of the coal is lacustrine, braided to meandering fluvial system, without the influence of any marine influx.The maceral composition of the Irwin River coal consists predominantly of vitrinite and inertinite, and minor exinite and mineral matter. The coal has very low semifusinite ratio and medium to high vitrinite content, suggesting the coal was deposited in anaerobic wet conditions with some degree of oxidation. The coal is classified as sub-bituminous of the Australian classification. The predominance of vitrite and clarite over inertite and durite contents in the coal indicates that the coal was formed in wetter conditions and in high water covers with a low degree of oxidation. Based on macerals and microlithotypes contents, the depositional environment of the coal is braided fluvial to deltaic, which is in accordance with the interpreted non- marine and mixed marine environment of deposition in the sub-basin.The petrological comparisons of Vasse Shelf, Collie and Irwin River coals show that the average vitrinite content of the Irwin River coal is highest (49.1%) and of the Collie coal is lowest (37.3%) of the three. The inertinite content is highest in Collie coal (49.1%), followed by Vasse Shelf (46.4%) and Irwin River (39.2%) coals. The exinite content is low in Irwin River coal (6.3%) as compared with Vasse Shelf (9.0°/,) and Collie (8.3%) coals. The mineral matter content ++ / is relatively low for all the three coals. The rank of the Vasse Shelf coal is high as compared with the Collie and Irwin River coals, either due to tectonic uplift after the deposition in post-Permian in the southern Perth Basin, or due to the average depth of burial over Vasse Shelf which is much greater than that of Collie and Irwin River coals.The comparisons of the coal from Western Australia with the selected Gondwana coals show that the predominance of inertinite over vitrinite occurs in the Western Australian coals (Vasse Shelf and Collie Basin). On the other hand, the Brazilian, eastern Australian, Indian and Western Australian (Irwin Sub-basin) coals are dominated by vitrinite over inertinite. The exinite content is highest in the Indian coals and lowest in the eastern Australian coals. The mineral matter content is highest in the Brazilian and Indian coals, and lowest in Western Australian (Vasse Shelf) and eastern Australian (Sydney Basin) coals. The rank of the coals ranges from sub- bituminous to medium volatile bituminous according to the Australian classification.
2

Rochas ornamentais do Espírito Santo e do Nordeste: avaliação da aplicabilidade através da caracterização tecnológica

Oliveira, Glenda Aparecida Rodrigues de 03 July 2015 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-03-18T13:52:39Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao GlendaOliveira.pdf: 2284714 bytes, checksum: 4ae41f1eca568b094bdbd2fe8b08c453 (MD5) / Made available in DSpace on 2016-03-18T13:52:39Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao GlendaOliveira.pdf: 2284714 bytes, checksum: 4ae41f1eca568b094bdbd2fe8b08c453 (MD5) Previous issue date: 2015-07-03 / CAPEs / Este trabalho consiste na avaliação dos resultados obtidos por meio de análise petrográfica e ensaios tecnológicos de sete litotipos de colorações cinza e amarela do Espírito Santo (Cinza Andorinha, Cinza Corumbá, Arabesco e Santa Cecília) e do Nordeste (Cinza Pocinhos, Cinza Corumbá e Amarelo Ipanema). Estes materiais são utilizados como rochas ornamentais e a determinação das correlações existentes entre essas características têm fundamental importância na investigação do desempenho e da durabilidade da rocha na função que lhe é destinada. Em se tratando de rochas de composição granítica, os resultados obtidos foram comparados àqueles estabelecidos pelas normas ABNT NBR 15844 (brasileira) e ASTM C 615 (americana). Segundo a NBR 15844 da ABNT, os ensaios necessários para a caracterização de rochas com finalidade ornamental são: análise petrográfica, índices físicos, resistência à flexão, resistência ao impacto de corpo duro, resistência à compressão, congelamento e degelo conjugados à compressão, desgaste Amsler e dilatação térmica, embora nem todos tenham sido realizados para os vários tipos de rochas estudados. Problemas técnicos impediram algumas análises. Os resultados dos materiais cinzas, independentemente de sua origem, são compatíveis com aqueles preconizados pela NBR 15844 e ASTM C 615, entretanto, os de coloração amarela apresentam valores muito próximos dos limites das normas. Isto pode ser explicado a partir da cor que é indício de processos de alteração, principalmente de minerais ferromagnesianos, (oxidação, hidroxidação, hidratação) que modificam as características de resistências dos materiais através de aumento de porosidade e absorção de água aparentes. Sabe-se que o aumento de porosidade diminui a resistência à compressão e consequentemente a resistência à tração (flexão). A maioria dos litotipos estudados apresentam valores adequados para utilização como material ornamental, com restrições para os litotipos de coloração amarela, que necessitam de impermeabilização quando de seu uso em áreas úmidas. Observa-se ainda que uma análise petrográfica/mineralógica mais aprofundada dos litotipos é recomendada para a previsão e aferição das propriedades físicas e mecânicas, bem como a correlação dos mesmos, com outros ensaios tecnológicos não apresentados neste trabalho para os litotipos estudados. / This work consists in the evaluation of the results obtained through petrographic analysis and technological tests of seven gray and yellow lithotypes from Espirito Santo, (Cinza Andorinha, Cinza Corumbá, Arabesco and Santa Cecília) and Brazil Northeast (Cinza Pocinhos, Cinza Corumbá and Amarelo Ipanema). These materials are used as ornamental rocks and the existing correlations among these traits have fundamental importance in performance and durability researches from the rock for the function which is intended. When it comes to rocks of granitic composition, the results obtained were compared to those established by the standards ABNT NBR 15844 (Brazilian) and ASTM C 615 (American). According to NBR ABNT 15844, the necessary tests for characterization of rocks with ornamental purpose are: petrographic analysis, physical indexes, flexural strength, impact resistance of hard body, compressive strength, freezing and thawing combined to compression, wear Amsler and thermal expansion, although not all of them have been carried out for the various rock types studied. Technical problems prevented some analysis. The results of grey materials, independently, are compatible with those recommended by NBR 15844 and ASTM C 615, however, the yellow rocks values are very close to the limits of the rules. This can be explained from the color that is indication of change processes, mainly ferromagnesian, mineral (rust, hidroxidation, moisturizing) that modify the resistance characteristics of materials through increased porosity and water absorption. It is known that the increase of porosity decreases the compressive strength and tensile strength (bending). Most of the lithotypes studied present suitable values for use as ornamental material, with restrictions to the lithotypes of yellow colour, in need of proofing when its use in humid areas. Note that further petrographic/mineralogical analysis of lithotypes is recommended for the prediction and measurement of physical and mechanical properties, as well as the correlation of the same with other technological tests presented in this work to the lithotypes.
3

Ορυκτοπετρογραφική μελέτη των λίθινων μνημείων του αρχαιολογικού χώρου της Ελευσίνας : ταυτοποίηση λιθοτύπων και διερεύνηση των αιτιών διάβρωσής τους

Ρούσσου, Ιωάννα 11 July 2013 (has links)
Σκοπός αυτής της μελέτης είναι η περιγραφή και αναγνώριση των λίθων του αρχαιολογικού χώρου της Ελευσίνας, τόσο μακροσκοπικά όσο και μικροσκοπικά. Η περιγραφή και αναγνώριση των λίθων έγινε με τη βοήθεια κυρίως πολωτικού μικροσκοπιόυ αλλά και ηλεκτρονικού μικροσκοπίου για την αναγνώριση ορυκτών που δεν είναι ορατά με το πολωτικό μικροσκόπιο. Στη συνέχεια γίνεται περιγραφή των φθορών που οι λίθοι έχουν υποστεί είτε λόγω φυσικών διεργασιών όπως διάβρωση- αποσάθρωση, είτε λόγω ανθρωπογενών παρεμβάσεων πάνω σε αυτούς. Η αναγνώριση και ονοματολογία των φθορών έγινε μακροσκοπικά, ενώ χρησιμοποιήθηκε επίσης και περιθλασιμετρία ακτίνων-Χ. Τέλος, παρατίθενται τρόποι που θα βοηθήσουν στην αντιμετώπιση των φθορών. / The aim of the study is to identify and describe, macroscopically and microscopically (optical and electronic microscopy), five main lithotypes of Eleusina’s archaeological place. Furthermore, it have been observed macroscopically the weathering forms on the stones of the monument and the alternation that take place on the surface of the stones due to industrial pollutants. X- ray diffraction have been also used. Finally, conservation methods are proposed for the treatment of the monuments.

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