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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.
21

Relação entre processo de corte e qualidade de superfícies serradas de granitos ornamentais / Relation between sawing process and quality of sawed surfaces of ornamental granites

Coimbra Filho, Clébio Goulart 05 October 2006 (has links)
A etapa de serragem de blocos (desdobramento) de granitos ornamentais considerando uma visão integrada entre as propriedades das rochas e o desempenho de máquinas, equipamentos e insumos, pode contribuir de forma fundamental para o aprimoramento do setor de rochas ornamentais. Mesmo com crescimentos marcantes na produção e exportação e grande avanço tecnológico, o empirismo predomina no processo produtivo aumentando a possibilidade de desperdícios, quebra de equipamentos, defeitos nas chapas, etc. Para minimizar a utilização da prática e otimizar o processo produtivo, este trabalho objetiva a correlação entre parâmetros operacionais e características tecnológicas das rochas para melhorar a qualidade das chapas produzidas. Foram acompanhadas as serragens e coletadas amostras de três materiais de grande demanda e efetuadas análises petrográficas, determinações da rugosidade e tratamentos estatísticos que, conjuntamente, com dados operacionais provenientes das serragens, avaliou-se a qualidade das superfícies serradas. Este estudo comprova a lacuna existente entre os estudos relacionados às variáveis envolvidas no processo de corte e as características petrográficas e da necessidade de uma pesquisa aplicada que permita a definição de procedimentos adequados na etapa de beneficiamento primário de granitos ornamentais, com a participação intensa das empresas que atuam nesse ramo da economia. / The industry of ornamental and dimension stone can be improved by the global and integrated overview of stone properties and performance machines, equipment and insums. Although with excellent growth in production and exportation and great technological advance, the empirism predominates in the productive process, a practice that might leads to loses, failures of equipment, defects in final product and other problems. Pointing this question are presented and correlated operational parameters of the sawing processes and technological properties of rocks, intending to contribute with the optimization of the productive processes and improve quality of slabs. Three varieties of granites were selected, sampled and subjected to petrographical analysis and rugosity evaluation. For each rock the block cut processes using gang saws was accompanied. The set of laboratorial and processes data was treated statistically and analyzed expecting to evaluate the quality of sawed surface slabs. The results obtained are not conclusive and pointing the necessity of future studies to understanding the effective relations between the petrographical features and processes procedures during block cut step in the dimension stone industry. Is expected this approach resulting in better guides to improve the quality of slabs and minimize loses during the processes.
22

Estudo comparativo do polimento de \"granitos\" com diferentes tipos de abrasivos / Comparative study of \"granites\" polishing with different types of abrasives

Almeida, Phillipe Fernandes de 25 April 2014 (has links)
O Brasil ocupa uma posição de destaque no cenário mundial da produção e exportação de rochas ornamentais devido a sua diversidade litológica e por abrigar todas as fases da cadeia produtiva, desde a lavra até o esquadrejamento de ladrilhos. No entanto, apesar da grande importância que este setor representa para a balança comercial mineral do país, muitos mecanismos físicos de seus processos industriais ainda não são corretamente entendidos, sendo realizados na maioria das vezes de forma empírica. A etapa de polimento das rochas ornamentais, que pode ser descrita como um processo em que o desgaste provocado por ferramentas abrasivas elimina as superfícies rugosas herdadas na etapa da serragem, ainda é um destes processos cujas variáveis envolvidas permanecem escassas de estudos. Na tentativa de torná-lo menos subjetivo, o Grupo de Tecnologia de Rochas (GTR) da Área de Pós-graduação em Geotecnia da EESC/USP, tem desenvolvido pesquisas abordando o enfoque da tribologia ao polimento, porém não esgotando todos os parâmetros envolvidos. Dando continuidade a estes estudos, a presente pesquisa abrange a simulação de polimento de 2 rochas \"graníticas\" utilizando-se dois tipos de abrasivos: os magnesianos, de uso mais tradicional, e o resinóide, um dos mais modernos utilizados atualmente. Foram usadas 9 combinações distintas, entre velocidade de rotação (200, 400 e 600 rpm), tempo (2, 4 e 6 minutos) para carga de 1 bar. Dentre as amostras submetidas ao processo, as com textura grossa e inequigranular mostraram certa limitação quanto à representatividade do equipamento SPR no desgaste abrasivo, não refletindo (necessariamente) a realidade do polimento industrial de granitos com mineralogia e textura similares. No entanto, em amostras com textura fina e equigranular, com baixa resistência à abrasão Amsler, os resultados expressos pelas perdas de massa (rocha e abrasivo) mostraram melhores superfície polida e qualidade de brilho, além de maior eficiência no polimento. / Brazil occupies a leading position on the global scenario of production and export of ornamental stones due to its geological diversity and by accommodate all stages of the supply chain, from quarrying to the tiles finishing. However, despite the great importance of this sector, many physical mechanisms of its industrial processes are still not properly understood and performed most often empirically. The polishing of ornamental stones, which can be described as a process where wearing caused by abrasive tools eliminates rough surfaces coming from the sawing stage, it is still one of the processes where the variables involved remain in scarce studies. In an attempt to become this process less subjective, the Geotechnical Engineering postgraduation department from the University of São Paulo (USP) at São Carlos School of Engineering has been developing researches approaching the focus of tribology in the polishing, but not exhausting all parameters involved. Following such studies, this research covers the polishing simulation of two granitic stones using two types of abrasives: the magnesian, more traditional, and resinoid, one of the most modern presently used. Nine different combinat ions were used between rotation speed (200, 400 and 600 rpm) and time (2, 4, and 6 minutes) to the 1 bar load. Among the samples subjected to the process, those with coarse and inequigranular texture showed some limitation to the representativeness of the SPR equipment in abrasive wearing, not necessarily reflecting the reality of industrial polishing of granites with similar mineralogy and texture. However, samples with fine and equigranular texture with low abrasive resistance, the results expressed by mass loss (stone and abrasive) showed better quality of the polished surface and gloss, besides a more efficient polishing.
23

Estratégias para a sustentabilidade da mineração de rochas ornamentais no noroeste do estado do Espírito Santo

Macedo, Dione January 2016 (has links)
O presente trabalho tem por objetivo contribuir com a atividade de extração de rochas ornamentais, por meio de propostas com recomendações que possam indicar passos a serem seguidos (guidelines) para a sustentabilidade desse setor, utilizando como estudo de caso a região noroeste do Estado do Espírito Santo. Para isso são feitas propostas de planejamento em longo prazo por meio do Processo Prospectivo e, em mais curto prazo, por um esquema de certificação sustentável para a atividade, com vistas à sustentabilidade desse polo produtor, considerando sua importância e os problemas existentes. O Processo Prospectivo, feito mediante a utilização da abordagem inicial do Processo Prospectivo, com a varredura (scanning) do ambiente, e aplicado para a região noroeste do estado do Espírito Santo, apresentou-se como uma ferramenta adequada para atingir os objetivos do presente estudo, principalmente por apontar, a partir dos resultados, além da sua continuidade, também a viabilidade de implementar uma certificação de sustentabilidade para o setor de rochas ornamentais, pela concordância observada nos resultados obtidos, na visão dos stakeholders. Para a proposta de certificação sustentável foi feita uma pesquisa por meio de questionário com stakeholders chave da indústria de rochas ornamentais para identificar a percepção desses com relação à iniciativa, que incluiu tópicos gerais e específicos divididos em três temas principais: sustentabilidade da indústria de rochas ornamentais no Brasil; desafios para a sustentabilidade dessa indústria e deficiências e omissões da regulamentação vigente, relativa a esses desafios; e a viabilidade de um processo de certificação sustentável para a indústria de rochas ornamentais no Espírito Santo e a participação dos stakeholders e de seus órgãos nesse processo. Os resultados obtidos com o desenvolvimento do presente estudo permitem concluir que, na visão dos stakeholders da indústria de rochas ornamentais do Brasil, em especial na visão daqueles do estado de Espírito Santo, a formalização das empresas do setor, aliada a um processo de certificação, tem potencial para gerar benefícios significativos para o desenvolvimento local e/ou regional sustentável, o que coincide com outras experiências apresentadas na literatura vigente. Os resultados também mostraram que ainda há muito a ser estudado antes que uma certificação sustentável seja implementada, mas que há sinais encorajadores para a continuidade do trabalho, pois parte significativa dos stakeholders (sociedade, governo e empresários do setor) respondeu favoravelmente a essa iniciativa para o setor, até mesmo em âmbito nacional. Nesse sentido, é reforçada a importância da cooperação entre o setor, a sociedade e governo federal, estadual e municipal em todo o processo, de modo a se criar uma cultura que possibilite a sustentabilidade efetiva desse setor. Finalmente, o trabalho mostra que, apesar dos desafios existentes, as propostas de continuidade do Processo Prospectivo e de viabilização de um processo de certificação sustentável têm potencial para aprimorar a indústria de rochas ornamentais pela adoção de critérios, que visem não somente as questões de caráter econômico, como aquelas que melhorem a performance social e ambiental para a efetiva sustentabilidade dessa indústria. / This work aims to contribute with dimension stones industry by doing proposals and recommendations of guidelines to the sustainability of this industry, based on northwest region of Espirito Santo State as case study. Long term planning by applying the Foresight and of short term a Sustainability Certification Scheme are proposed in order to achieve the sustainability of the producer pole by considering its relevance and the existents problems. Foresight was applied for the northwest region using an initial approach of Foresight with the scanning of the environment, and it is presented as an appropriate tool to achieve the objectives of this study, mainly to point out from the results not only its continuity, but also the feasibility of implementing a sustainability certification scheme for the dimension stones industry, by the agreement observed in the results, in the view of stakeholders. For the sustainability certification scheme a survey was conducted with key stakeholders of the dimension stones industry to identify their perceptions regarding to the initiative, which included general and specific topics in three themes: sustainability of the dimension stones industry in Brazil; challenges to the sustainability of the dimension stones industry, and deficiencies and omissions of current regulatory processes regarding these challenges; and the feasibility of a sustainability certification scheme for the dimension stones industry in Espírito Santo State and the participation of entities/bodies/agencies in this process. The results obtained with the development of this study allow us to conclude that, in the view of stakeholders of the dimension stone industry in Brazil, especially the Espírito Santo State, the formalization of companies in the industry, combined with a certification process has the potential to generate significant benefits for local and/or regional sustainable development, which coincides with other experiences presented in current literature. The results also showed that there is still too much to be studied before a sustainability certification scheme is implemented, but there are encouraging signs for the continuity of the work, as a significant part of stakeholders (society, government and industry entrepreneurs) responded favorably to this initiative the industry, even at the national level. In this sense, it is reinforced the importance of cooperation between industry, society and federal, state and local government throughout the process, in order to create a culture that enables the sustainability of this sector. Finally, the study shows that despite the existing challenges, proposals for continuity of the Foresight and achieving a sustainability certification scheme have the potential to improve the dimension stones industry by adopting criteria that not only consider the economic issues of the industry, but also to improve its social and environmental performance for effective sustainability of this industry.
24

Relação entre processo de corte e qualidade de superfícies serradas de granitos ornamentais / Relation between sawing process and quality of sawed surfaces of ornamental granites

Clébio Goulart Coimbra Filho 05 October 2006 (has links)
A etapa de serragem de blocos (desdobramento) de granitos ornamentais considerando uma visão integrada entre as propriedades das rochas e o desempenho de máquinas, equipamentos e insumos, pode contribuir de forma fundamental para o aprimoramento do setor de rochas ornamentais. Mesmo com crescimentos marcantes na produção e exportação e grande avanço tecnológico, o empirismo predomina no processo produtivo aumentando a possibilidade de desperdícios, quebra de equipamentos, defeitos nas chapas, etc. Para minimizar a utilização da prática e otimizar o processo produtivo, este trabalho objetiva a correlação entre parâmetros operacionais e características tecnológicas das rochas para melhorar a qualidade das chapas produzidas. Foram acompanhadas as serragens e coletadas amostras de três materiais de grande demanda e efetuadas análises petrográficas, determinações da rugosidade e tratamentos estatísticos que, conjuntamente, com dados operacionais provenientes das serragens, avaliou-se a qualidade das superfícies serradas. Este estudo comprova a lacuna existente entre os estudos relacionados às variáveis envolvidas no processo de corte e as características petrográficas e da necessidade de uma pesquisa aplicada que permita a definição de procedimentos adequados na etapa de beneficiamento primário de granitos ornamentais, com a participação intensa das empresas que atuam nesse ramo da economia. / The industry of ornamental and dimension stone can be improved by the global and integrated overview of stone properties and performance machines, equipment and insums. Although with excellent growth in production and exportation and great technological advance, the empirism predominates in the productive process, a practice that might leads to loses, failures of equipment, defects in final product and other problems. Pointing this question are presented and correlated operational parameters of the sawing processes and technological properties of rocks, intending to contribute with the optimization of the productive processes and improve quality of slabs. Three varieties of granites were selected, sampled and subjected to petrographical analysis and rugosity evaluation. For each rock the block cut processes using gang saws was accompanied. The set of laboratorial and processes data was treated statistically and analyzed expecting to evaluate the quality of sawed surface slabs. The results obtained are not conclusive and pointing the necessity of future studies to understanding the effective relations between the petrographical features and processes procedures during block cut step in the dimension stone industry. Is expected this approach resulting in better guides to improve the quality of slabs and minimize loses during the processes.
25

Signs and symbols represented in Germanic, particularly Scandinavian, iconography between the Migration Period and the end of the Viking Age.

Hupfauf, Peter Rudolf Martin January 2003 (has links)
This research focuses on the analysis of pictorial images from objects of Germanic/early Scandinavian cultures in order to discriminate elements which are only applied for decorative reasons from those which also express symbolic values. At the outset I introduced an interpretation of the terms �signs� and �symbols� in order to inform the reader to which extent these terms were applied. It appeared that techniques, such as the geographical and chronological classification, traditionally used by archaeologists and historians to analyse objects/artefacts, were not always sufficient enough to gain all information which images may offer. Sometimes it seems to be difficult to determine if certain images shown on objects from early mediaeval, central and northern European origin, were created as a space-filling decoration only or if they held additional, probably symbolic, information as well. I have investigated aspects from visual perception, as applied within the domains of psychology, visual art and design. The methods, as they are introduced in this thesis, can be used as a identification scheme, applied on objects of great diversity. I have applied them on guldgubber (little embossed gold foils), bracteates and Gotland picture-stones. Objects of great historical and geographic difference, as well as physical diversity, such as size and material were chosen purposely to create an overview of the symbolic expressions in Germanic/early Scandinavian artefacts and to test the extent of the identification method derived from the domain of visual perception. A detailed analysis of sixty four guldgubber, found in Lundeborg, near Gudme, on the island of Fyn (Denmark), is placed in an appendix. An analysis of these objects appeared to be particularly interesting because it is not known what the purpose of guldgubber were to the present day.
26

moyar : hafin : iþra : byn : reta; Flickor, förrätta era böner väl : social struktur i gotländska runinskrifter under medeltid / moyar : hafin : iþra : byn : reta; Girls, say your prayers right : social structure in medeival rune inscriptions on Gotland

Andreasson, Kajsa January 2010 (has links)
<p>This paper discusses runic inscriptions from the middle ages on Gotland and how they portray social structure. It focuses on three themes: (1) fixed time and space, (2) women and the nuclear family and (3) profession and social status/structure. It also discusses changes brought on by a more structured and established Christianity, as well as differences between medieval rune stones on Gotland and their predecessors Viking Age rune stones in the Mälar Valley.</p>
27

Conservation of Gotland sandstone : overview of present conditions, evaluation of methods /

Myrin, Malin. January 2006 (has links)
Thesis (doctor of philosophy)--Göteborg University, 2006. / Includes bibliographical references.
28

moyar : hafin : iþra : byn : reta; Flickor, förrätta era böner väl : social struktur i gotländska runinskrifter under medeltid / moyar : hafin : iþra : byn : reta; Girls, say your prayers right : social structure in medeival rune inscriptions on Gotland

Andreasson, Kajsa January 2010 (has links)
This paper discusses runic inscriptions from the middle ages on Gotland and how they portray social structure. It focuses on three themes: (1) fixed time and space, (2) women and the nuclear family and (3) profession and social status/structure. It also discusses changes brought on by a more structured and established Christianity, as well as differences between medieval rune stones on Gotland and their predecessors Viking Age rune stones in the Mälar Valley.
29

The idea of lapidary medicine its circulation and practical applications in medieval and early modern England: 1000-1750 /

Harris, Nichola Erin, January 2009 (has links)
Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in History." Includes bibliographical references (p. 209-250).
30

Signs and symbols represented in Germanic, particularly Scandinavian, iconography between the Migration Period and the end of the Viking Age.

Hupfauf, Peter Rudolf Martin January 2003 (has links)
This research focuses on the analysis of pictorial images from objects of Germanic/early Scandinavian cultures in order to discriminate elements which are only applied for decorative reasons from those which also express symbolic values. At the outset I introduced an interpretation of the terms �signs� and �symbols� in order to inform the reader to which extent these terms were applied. It appeared that techniques, such as the geographical and chronological classification, traditionally used by archaeologists and historians to analyse objects/artefacts, were not always sufficient enough to gain all information which images may offer. Sometimes it seems to be difficult to determine if certain images shown on objects from early mediaeval, central and northern European origin, were created as a space-filling decoration only or if they held additional, probably symbolic, information as well. I have investigated aspects from visual perception, as applied within the domains of psychology, visual art and design. The methods, as they are introduced in this thesis, can be used as a identification scheme, applied on objects of great diversity. I have applied them on guldgubber (little embossed gold foils), bracteates and Gotland picture-stones. Objects of great historical and geographic difference, as well as physical diversity, such as size and material were chosen purposely to create an overview of the symbolic expressions in Germanic/early Scandinavian artefacts and to test the extent of the identification method derived from the domain of visual perception. A detailed analysis of sixty four guldgubber, found in Lundeborg, near Gudme, on the island of Fyn (Denmark), is placed in an appendix. An analysis of these objects appeared to be particularly interesting because it is not known what the purpose of guldgubber were to the present day.

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