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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

Estudo do comportamento tecnológico e de alterabilidade das rochas ornamentais silicáticas verde Amazonas, preto Cajugram e bege Ipanema - (ES) /

Carvalho, Cássio Santos de. January 2010 (has links)
Orientador: Antonio Carlos Artur / Banca: Fabiano Cabañas Navarro / Banca: Tamar Milca Bortolozzo Galembeck / Resumo: As rochas ornamentais Verde Amazonas, Preto Cajugram e Bege Ipanema exploradas no estado do Espírito Santo, respectivamente um charnockito, um hiperstênio monzodiorito e um ortognaisse, foram submetidas a uma bateria de ensaios físico-mecânicos e de resistência ao ataque químico sob ação controlada dos compostos NH4Cl, NaClO, C6H8O7, HCl e KOH presentes na composição de produtos de uso doméstico e de determinadas soluções concentradas dos ácidas HCl, H2SO4 e HNO3 simulando atmosferas agressivas. A avaliação dos efeitos dos agentes químicos foram realizadas à luz das variações da propagação de ondas ultrassônicas, da resistência à flexão 4 pontos e do lustro da superfície polida das rochas testadas, bem como pela caracterização dos produtos de subeflorescências e eflorescências geradas pelas reações com os ácidos. Os resultados dos diferentes testes realizados foram confrontados com as propriedades petrográficas de cada rocha. Os resultados obtidos para os parâmetros físico-mecânicos e de alterabilidade química indicam, com algumas reservas, que as três rochas são detentoras de boas qualidades para utilização como rochas ornamentais e para revestimentos em obras civis. Os estudos revelaram que o comportamento tecnológico e de alterabilidade química dos materiais avaliados é controlado pela inter-relação dos aspectos composicionais, estruturais e texturais das rochas. O charnockito Verde Amazonas, rocha verde escura megaporfirítica gnaissificada com matriz de granulação média a grossa e com elevado grau de microfissuramento transgranulares, apresentou bom desempenho no tocante a resistência mecânica, mas foi o material que mostrou maior sensibilidade aos efeitos da maioria dos agentes químicos com desbotamento, clareamento, amarelamento e ofuscamento das superfícies polidas. O Preto Cajugram com estrutura isotrópica, textura equigranular... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Amazon Green, Cajugram Black and Ipanema Beige dimension stones explored in the state of Espirito Santo, respectively, a charnockite, a hypersthene monzodiorite and a orthogneiss, underwent a serie of physical-mechanical and resistance to chemical attack tests under controlled action of the chemicals NH4Cl, NaClO, C6H8O7, HCl and KOH, present in the composition of household products and certain concentrated solutions of the acids HCl, H2SO4 and HNO3, simulating aggressive atmospheres. The evaluation of the effects of the chemical agents was performed in the light of changes in the propagation of ultrasonic sound waves, the 4-point flexural strength and gloss of the polished surface of the tested rock samples, as well as the characterization of the products of efflorescences and subefflorescences, generated by reactions with the acids. The results of the different tests were compared with the petrographic properties of each rock. The obtained results for the physic-mechanical parameters and for the chemical alterability indicates, with some reservations, that the three rocks shows good quality for use as dimension stones and coatings in civil works. Studies show that the behavior of technology and chemical alterability of the tested materials is controlled by the interrelation of the compositional, structural and textural aspects of the rocks. The charnockite Verde Amazonas, dark green megaporphyritic gneissic rock, with medium to coarse grained matrix and a high degree of transgranular microcracking, showed good performance regarding mechanical strength, but was the most sensitive material to the effects of most chemical agents as fading, bleaching, yellowing and glare from the polished surfaces. The Preto Cajugram, with isotropic structure, medium equigranular texture, and low degree of microcracking, has the highest mechanical strengths. On the other hand, it displays the highest... (Complete abstract click electronic access below) / Mestre
2

Diagênese da Formação Corumbataí na Mina Partezani, Rio Claro - SP

Bernardes, Eduardo Silveira [UNESP] 27 April 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-04-27Bitstream added on 2014-06-13T19:06:31Z : No. of bitstreams: 1 bernardes_es_dr_rcla.pdf: 1067716 bytes, checksum: eefeb5fec6ee0538ca62fc18647588e5 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A Formação Corumbataí (Permiano) foi estudada em suas variações verticais, em duas frentes de lavra nas proximidades de Rio Claro, enfocando as relações entre os componentes mineralógicos e as propriedades cerâmicas. A análise petrográfica das amostras coletadas nessas minas, por meio de microscópio óptico, juntamente com Microscopia Eletrônica de Varredura (MEV) dos minerais do cimento e Difração de Raios-X (DRX) com a fração argila, revelou uma assembléia mineralógica complexa com quartzo e feldspato na dimensão silte, matriz constituída por illita, esmectita-clorita, chamosita, berthierina e argilominerais interestratificados, e hematita, calcita e albita como cimento dessas rochas. Os sedimentos originais, pelíticos e ricos em ferro, foram modificados pelos eventos diagenéticos, durante a interação com soluções conatas alcalinas; processos de substituição e autigênese sucederam a diagênese inicial promovendo a formação de diferentes tipos de cimento e o crescimento dos cristais de illita. Os filossilicatos hidratados e amorfos de sílica precipitados na interface sedimento-água deram origem a esses minerais através de transformações associadas à perda de água interplanar e trocas catiônicas com os fluidos hipersalinos iniciais, mas também há evidências de forte influência de eventos magmáticos que teriam desencadeado novas transformações diagenéticas. A diagênese tardia sob influência de processos superficiais sob ação de águas meteóricas também está registrada em algumas feições, embora mais restrita pela característica impermeável dos litotipos. Os principais horizontes estratigráficos foram descritos em termos de litotipo, textura, conteúdo em argila e minerais do cimento. Análise de Componentes Principais e de Agrupamento reforça a correlação entre as feições texturais (granulometria e maturidade) e as propriedades físicas do material. / The Late Permian Corumbataí Formation was studied in its vertical variability within a couple of mine works close to Rio Claro, focusing relationships between mineralogical components and ceramics properties. The petrographic analysis of the samples collected in these mines, made by optical microscopic, Scanning Eletron Microscopy (SEM) of the cement minerals and X-ray techniques with clay fraction, revealed a complex mineralogical assemblage with quartz and feldspar in silt size grains, within a matrix constituted by illite, smectite-chlorite, chamosite, berthierine and interestratified clay-minerals, with cement of hematite, calcite and albite. The original fine-grained iron-rich sediment was modified by diagenetic events, during the interaction with alcalline conate solutions; mineralogical substitution and authigenesis followed this early diagenesis with the formation of different types of cement. The hidrous phyllosilicates and the amorphous silica precipited in the water-sediment interface played an important role on these transformations, but there are evidences of strong influence of magmatic events wich promoted another diagenetic phase generation. The principal stratigraphic horizons were described in terms of lithology, texture, argillaceous content and cement minerals. Principal Components and Clusters Analysis strains the correlation between textural features (grain size and maturity) and physical properties of the material.
3

Diagênese da Formação Corumbataí na Mina Partezani, Rio Claro - SP /

Bernardes, Eduardo Silveira. January 2005 (has links)
Resumo: A Formação Corumbataí (Permiano) foi estudada em suas variações verticais, em duas frentes de lavra nas proximidades de Rio Claro, enfocando as relações entre os componentes mineralógicos e as propriedades cerâmicas. A análise petrográfica das amostras coletadas nessas minas, por meio de microscópio óptico, juntamente com Microscopia Eletrônica de Varredura (MEV) dos minerais do cimento e Difração de Raios-X (DRX) com a fração argila, revelou uma assembléia mineralógica complexa com quartzo e feldspato na dimensão silte, matriz constituída por illita, esmectita-clorita, chamosita, berthierina e argilominerais interestratificados, e hematita, calcita e albita como cimento dessas rochas. Os sedimentos originais, pelíticos e ricos em ferro, foram modificados pelos eventos diagenéticos, durante a interação com soluções conatas alcalinas; processos de substituição e autigênese sucederam a diagênese inicial promovendo a formação de diferentes tipos de cimento e o crescimento dos cristais de illita. Os filossilicatos hidratados e amorfos de sílica precipitados na interface sedimento-água deram origem a esses minerais através de transformações associadas à perda de água interplanar e trocas catiônicas com os fluidos hipersalinos iniciais, mas também há evidências de forte influência de eventos magmáticos que teriam desencadeado novas transformações diagenéticas. A diagênese tardia sob influência de processos superficiais sob ação de águas meteóricas também está registrada em algumas feições, embora mais restrita pela característica impermeável dos litotipos. Os principais horizontes estratigráficos foram descritos em termos de litotipo, textura, conteúdo em argila e minerais do cimento. Análise de Componentes Principais e de Agrupamento reforça a correlação entre as feições texturais (granulometria e maturidade) e as propriedades físicas do material. / Abstract: The Late Permian Corumbataí Formation was studied in its vertical variability within a couple of mine works close to Rio Claro, focusing relationships between mineralogical components and ceramics properties. The petrographic analysis of the samples collected in these mines, made by optical microscopic, Scanning Eletron Microscopy (SEM) of the cement minerals and X-ray techniques with clay fraction, revealed a complex mineralogical assemblage with quartz and feldspar in silt size grains, within a matrix constituted by illite, smectite-chlorite, chamosite, berthierine and interestratified clay-minerals, with cement of hematite, calcite and albite. The original fine-grained iron-rich sediment was modified by diagenetic events, during the interaction with alcalline conate solutions; mineralogical substitution and authigenesis followed this early diagenesis with the formation of different types of cement. The hidrous phyllosilicates and the amorphous silica precipited in the water-sediment interface played an important role on these transformations, but there are evidences of strong influence of magmatic events wich promoted another diagenetic phase generation. The principal stratigraphic horizons were described in terms of lithology, texture, argillaceous content and cement minerals. Principal Components and Clusters Analysis strains the correlation between textural features (grain size and maturity) and physical properties of the material. / Orientador: Sebastião Gomes de Carvalho / Coorientador: Erasto Boretti de Almeida / Banca: Paulo Miranda de Figueiredo Filho / Banca: José Francisco Marciano Motta / Banca: Marcos Roberto Masson / Banca: Antenor Zanardo / Doutor
4

Comparison Of Scaling Performance Between Sidewalks Placed Using Hot and Cold Weather Concreting Procedures

Rudraraju, Likhitha 03 April 2023 (has links) (PDF)
This study investigates the performance of concrete sidewalks placed using hot and cold weather concreting practices. The effect that curing methods, types of deicers, and supplementary cementitious material content have on the scaling resistance of concrete is examined in the laboratory and the field. After one winter, petrographic analysis was conducted on the cores from the sidewalk panels. The results from field evaluation indicate that the concrete sidewalks placed using hot weather concreting showed better resistance against scaling than those placed using cold weather concreting. The results also suggest that the effect of curing method depends on the concreting procedure type. The results confirm the maximum limits recommended by ACI 201.2R Guide for Durable Concrete, the mix proportions with fly ash less than 25% and slag less than 50% have shown better scaling resistance. Based on the petrographic analysis, a correlation between the properties of concrete determined through petrography and scaling on a sidewalk could not be determined.
5

Characterization of Middle and Later Stone Age lithic artifacts from two rockshelter sites in Iringa Region, southern Tanzania

Biittner, Katie 11 1900 (has links)
Stone tools have a critical role to play in our understanding of the behavior of early humans. In particular, the types of raw materials that are present in stone tool assemblages, and the sources from which they are acquired, provide information relating to decision making processes, planning, organization of technology, and group mobility. The characterization of Stone Age lithic artifact assemblages from two rockshelter sites in southern Tanzania, Magubike and Mlambalasi, allowed for the evaluation of inter- and intra-assemblage variability. Raw material characterization was conducted using macroscopic and microscopic analyses. Numerous raw material sourcing studies have been undertaken on Stone Age lithic assemblages recovered from sites in Tanzania and the rest of East Africa. Generally these studies have concentrated on identifying the sources of a particular type of stone raw material such as chert, obsidian, and basalt; however, rarely are the attributes of the whole assemblage examined. Furthermore, few archaeologists describe stone materials in terms of their basic petrographic characteristics. Both of these weaknesses are the direct result of the lack of a standardized methodology for describing lithic raw materials, thus this dissertation outlines a strategy for raw material sourcing, with a focus on description and grounded in geoarchaeological theory. When combined with typological and technological analyses, the results of the raw material analyses suggests the exclusive use of locally acquired lithics.
6

Characterization of Middle and Later Stone Age lithic artifacts from two rockshelter sites in Iringa Region, southern Tanzania

Biittner, Katie Unknown Date
No description available.
7

COMPOSITIONAL PERSPECTIVES ON THE EXCHANGE OF MUNA SLATE WARES IN THE LATE AND TERMINAL CLASSIC NORTHERN MAYA LOWLANDS

Gunn, Christopher M. 01 January 2002 (has links)
This thesis presents the results of petrographic point counting analyses of Muna Slate ware, thepredominant slipped ceramic ware in the Northern Maya Lowlands during the Late and TerminalClassic Periods (600-1000 A.D.) of Maya prehistory. Recently, it was hypothesized that MunaSlate wares were centrally produced and distributed from the Puuc Hills site of Sayil (Smyth andDore 1994; Smyth et al. 1995). Given that Muna Slate wares may be considered utilitariansubsistence items (sensu Brumfiel and Earle 1987), this suggestion runs counter to severalarguments that ancient Maya utilitarian ceramics production is associated with outlyingcommunities and that their distribution is localized. In the research presented here, the model ofMuna Slate ware production presented for Sayil is evaluated in terms of ceramic ecology,economic theory and models of craft distribution, the culture-historical context of Muna Slateware use, and previous studies of ceramic production and distribution in the Maya Lowlands.Muna Slate wares from three sites in the northern Lowlands - Kiuic, Labná, and Ek Balam –were then analyzed in order to test the whether or not Sayil was the sole producer of theseceramics.
8

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.
9

Influência da petrografia sobre a anisotropia à tensão de compressão e dilatação térmica de rochas ornamentais /

Navarro, Fabiano Cabañas. January 2006 (has links)
Orientador: Antonio Carlos Artur / Banca: Antenor Braga Paraguassú / Banca: José Eduardo Rodrigues / Banca: Maria Heloisa Barros de Oliveira Frascá / Banca: Peter Christian Hackspacher / Resumo: Considerando um conjunto de 21 tipos de rochas utilizadas como revestimento e subdivididas em quatro conjuntos por afinidade da composição mineral (rochas carbonáticas, quartzosas, feldspáticas e quartzo-feldspáticas) foram realizados ensaios tecnológicos para a determinação do coeficiente de dilatação térmica linear e da resistência à compressão uniaxial, bem como a anisotropia dessas propriedades. Os dados tecnológicos obtidos foram correlacionados com informações petrográficas qualitativas e quantitativas referentes à composição mineral, variações texturais e estruturais determinadas em seções ortogonais entre si a partir de um sistema de referência (xyz) baseado na foliação e lineação macroscopicamente visíveis. A análise integrada dos dados utilizando estatística convencional e multivariada procurou apontar as variáveis petrográficas mais relevantes para as duas propriedades tecnológicas enfocadas e suas respectivas anisotropias. A dilatação térmica e sua anisotropia são influenciadas principalmente pela composição mineral e pela orientação preferencial dos minerais embora as microfissuras desempenhem papel importante em alguns casos. A tensão de compressão mostra sua variabilidade e anisotropia influenciadas pela granulação média, tipos de contatos minerais predominantes e padrões de microfissuras mais ou menos definidos por influência da foliação presente. Constatou-se que no conjunto analisado a presença da foliação não implica necessariamente em anisotropia das duas propriedades estudadas. / Abstract: The anisotropy of thermal expansion coefficient and compressive tensile strength were determined for 21 commercially used stones gathered in four set according the main mineral composition named carbonatic, quartz-rich, feldspar-rich and quartz-feldspar-rich rocks. Using a coordinate reference system (xyz) based on the macroscopic visible foliation and lineation the samples were submitted to normalized laboratorial analyses for determination of the both technological properties and the petrographical features such as mineral composition, texture and fabric. Additionally was carried out measurements of weathered area and microcrack quantification by image analysis and texture quantification by U-stage methods. In order to understand the relationship between the anisotropy measured and petrographical data it was applied traditional and multivariate statistical analysis. The results pointed to the great significance of mineral composition and the crystallographic preferred orientation for thermal expansion and respective anisotropy, especially to monomineralic and/or foliated rocks, in spite of some cases microcracks play this role. The compressive strength is mainly controlled by a complex interaction between grain size distribution, grain boundary and microcrack patterns related or not to foliation. / Doutor
10

Estudo do comportamento tecnológico e de alterabilidade das rochas ornamentais silicáticas verde Amazonas, preto Cajugram e bege Ipanema - (ES)

Carvalho, Cássio Santos de [UNESP] 17 September 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-17Bitstream added on 2014-06-13T19:54:19Z : No. of bitstreams: 1 carvalho_cs_me_rcla.pdf: 8151114 bytes, checksum: e14fc35948f60546fa7a69931710c333 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As rochas ornamentais Verde Amazonas, Preto Cajugram e Bege Ipanema exploradas no estado do Espírito Santo, respectivamente um charnockito, um hiperstênio monzodiorito e um ortognaisse, foram submetidas a uma bateria de ensaios físico-mecânicos e de resistência ao ataque químico sob ação controlada dos compostos NH4Cl, NaClO, C6H8O7, HCl e KOH presentes na composição de produtos de uso doméstico e de determinadas soluções concentradas dos ácidas HCl, H2SO4 e HNO3 simulando atmosferas agressivas. A avaliação dos efeitos dos agentes químicos foram realizadas à luz das variações da propagação de ondas ultrassônicas, da resistência à flexão 4 pontos e do lustro da superfície polida das rochas testadas, bem como pela caracterização dos produtos de subeflorescências e eflorescências geradas pelas reações com os ácidos. Os resultados dos diferentes testes realizados foram confrontados com as propriedades petrográficas de cada rocha. Os resultados obtidos para os parâmetros físico-mecânicos e de alterabilidade química indicam, com algumas reservas, que as três rochas são detentoras de boas qualidades para utilização como rochas ornamentais e para revestimentos em obras civis. Os estudos revelaram que o comportamento tecnológico e de alterabilidade química dos materiais avaliados é controlado pela inter-relação dos aspectos composicionais, estruturais e texturais das rochas. O charnockito Verde Amazonas, rocha verde escura megaporfirítica gnaissificada com matriz de granulação média a grossa e com elevado grau de microfissuramento transgranulares, apresentou bom desempenho no tocante a resistência mecânica, mas foi o material que mostrou maior sensibilidade aos efeitos da maioria dos agentes químicos com desbotamento, clareamento, amarelamento e ofuscamento das superfícies polidas. O Preto Cajugram com estrutura isotrópica, textura equigranular... / The Amazon Green, Cajugram Black and Ipanema Beige dimension stones explored in the state of Espirito Santo, respectively, a charnockite, a hypersthene monzodiorite and a orthogneiss, underwent a serie of physical-mechanical and resistance to chemical attack tests under controlled action of the chemicals NH4Cl, NaClO, C6H8O7, HCl and KOH, present in the composition of household products and certain concentrated solutions of the acids HCl, H2SO4 and HNO3, simulating aggressive atmospheres. The evaluation of the effects of the chemical agents was performed in the light of changes in the propagation of ultrasonic sound waves, the 4-point flexural strength and gloss of the polished surface of the tested rock samples, as well as the characterization of the products of efflorescences and subefflorescences, generated by reactions with the acids. The results of the different tests were compared with the petrographic properties of each rock. The obtained results for the physic-mechanical parameters and for the chemical alterability indicates, with some reservations, that the three rocks shows good quality for use as dimension stones and coatings in civil works. Studies show that the behavior of technology and chemical alterability of the tested materials is controlled by the interrelation of the compositional, structural and textural aspects of the rocks. The charnockite Verde Amazonas, dark green megaporphyritic gneissic rock, with medium to coarse grained matrix and a high degree of transgranular microcracking, showed good performance regarding mechanical strength, but was the most sensitive material to the effects of most chemical agents as fading, bleaching, yellowing and glare from the polished surfaces. The Preto Cajugram, with isotropic structure, medium equigranular texture, and low degree of microcracking, has the highest mechanical strengths. On the other hand, it displays the highest... (Complete abstract click electronic access below)

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