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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

Avaliação do emprego de filito como carga em plastisol. / Evaluation of the use of phyllite as filler in plastisol.

Ribeiro, Alcidio Pinheiro 17 January 2003 (has links)
Apresenta-se aqui a caracterização do filito e a avaliação da sua aplicação como carga mineral na produção de materiais plásticos. Amostras de jazidas em lavra no município de Itapeva, sudoeste do Estado de São Paulo, foram preparadas em laboratório, através de secagem e peneiramento, e analisadas física e quimicamente, sendo comparadas com outros minérios utilizados comumente como cargas minerais. Uma dessas amostras, após sua preparação, foi aplicada como carga na produção de peças plásticas no Centro Técnico de Serviços CTS da empresa Braskem S.A., a partir de pastas formadas com PVC e plastificantes, conhecidas como plastisóis. O filito foi incorporado em varias formulações de compostos utilizados para produção de bolas plásticas comuns. Os resultados, em termos de resistência mecânica, foram comparados com os de compostos contendo carbonato de cálcio natural, moído, em malha inferior a 44 m. O carbonato de cálcio natural, ou calcita, constitui a carga mais tradicionalmente utilizada nesse setor industrial. Os testes realizados indicaram que o filito confere ao material polimérico produzido, composto de polímeros, aditivos e cargas, propriedades desejáveis de resistência mecânica e acabamento, algumas propriedades resultando melhores que as obtidas com o uso da calcita para determinadas proporções e formulações. Os resultados obtidos permitem concluir que o filito beneficiado comporta-se similarmente a minerais industriais tradicionais e pode vir a ser empregado na indústria de plásticos dito reforçados na geração de produtos diversos tais como bolas de parque, cabeças de bonecas, tapetes, tubos plásticos flexíveis e painéis de veículos, entre outros segmentos do setor. / This paper presents the characterization of the White-phyllite and an evaluation of its application as filler in the production of plastic materials. Phyllite samples with origin in ore body located in the district of Itapeva, southwest area of Sao Paulo State, they were beneficiated, prepared in laboratory through granulometric separation and drying and applied in the production of reinforced thermoplastic (Plastisol) in laboratories of the Braskem S. A. located in São Paulo city. The accomplished tests indicated that the beneficiated phyllite checks to the material plastic produced desirable properties of mechanical resistance and finish. The use of the phyllite it was compared with the calcite in the production of the plastics materials in several composition and proportions, showing in some compositions strips better than obtained results them with the calcite, traditional filler used for those products. The obtained results allow to conclude that the phyllite, properly beneficiated, is similar to traditional industrial minerals and it can benefit the industry of plastics reinforced in the production, among others, of balls, doll heads, rubber rugs, flexible plastic tubes, panels of vehicles.
2

Avaliação do emprego de filito como carga em plastisol. / Evaluation of the use of phyllite as filler in plastisol.

Alcidio Pinheiro Ribeiro 17 January 2003 (has links)
Apresenta-se aqui a caracterização do filito e a avaliação da sua aplicação como carga mineral na produção de materiais plásticos. Amostras de jazidas em lavra no município de Itapeva, sudoeste do Estado de São Paulo, foram preparadas em laboratório, através de secagem e peneiramento, e analisadas física e quimicamente, sendo comparadas com outros minérios utilizados comumente como cargas minerais. Uma dessas amostras, após sua preparação, foi aplicada como carga na produção de peças plásticas no Centro Técnico de Serviços CTS da empresa Braskem S.A., a partir de pastas formadas com PVC e plastificantes, conhecidas como plastisóis. O filito foi incorporado em varias formulações de compostos utilizados para produção de bolas plásticas comuns. Os resultados, em termos de resistência mecânica, foram comparados com os de compostos contendo carbonato de cálcio natural, moído, em malha inferior a 44 m. O carbonato de cálcio natural, ou calcita, constitui a carga mais tradicionalmente utilizada nesse setor industrial. Os testes realizados indicaram que o filito confere ao material polimérico produzido, composto de polímeros, aditivos e cargas, propriedades desejáveis de resistência mecânica e acabamento, algumas propriedades resultando melhores que as obtidas com o uso da calcita para determinadas proporções e formulações. Os resultados obtidos permitem concluir que o filito beneficiado comporta-se similarmente a minerais industriais tradicionais e pode vir a ser empregado na indústria de plásticos dito reforçados na geração de produtos diversos tais como bolas de parque, cabeças de bonecas, tapetes, tubos plásticos flexíveis e painéis de veículos, entre outros segmentos do setor. / This paper presents the characterization of the White-phyllite and an evaluation of its application as filler in the production of plastic materials. Phyllite samples with origin in ore body located in the district of Itapeva, southwest area of Sao Paulo State, they were beneficiated, prepared in laboratory through granulometric separation and drying and applied in the production of reinforced thermoplastic (Plastisol) in laboratories of the Braskem S. A. located in São Paulo city. The accomplished tests indicated that the beneficiated phyllite checks to the material plastic produced desirable properties of mechanical resistance and finish. The use of the phyllite it was compared with the calcite in the production of the plastics materials in several composition and proportions, showing in some compositions strips better than obtained results them with the calcite, traditional filler used for those products. The obtained results allow to conclude that the phyllite, properly beneficiated, is similar to traditional industrial minerals and it can benefit the industry of plastics reinforced in the production, among others, of balls, doll heads, rubber rugs, flexible plastic tubes, panels of vehicles.
3

Τεκτονική ανάλυση της επαφής μεταξύ Φυλλιτικής-Χαλαζιτικής σειράς και ζώνης Τρίπολης στην περιοχή του Πάρνωνα

Παρασκευουλάκου Μπόκολα, Παναγιώτα 16 May 2014 (has links)
Τεκτονική ανάλυση της επαφής της Φυλλιτικής-Χαλαζιτικής σειράς και των ασβεστόλιθων Τριπόλεως στο ανατολικό περιθώριο του Πάρνωνα. Καθώς όμως και η τεκτονική ανάλυση και η γεωλογική ιστορία της ευρύτερης περιοχής των τεκτονικών παραθύρων, του Πάρνωνα και του Ταΰγετου. / Stractural analysis of the contact of the Phyllite-Quartzite series and the Tripolitsa limestones to the eastern margin of Parnon. As, however, the structural analysis and the geological history of the region of two tectonic windows of Parnon and Taygetos.
4

Η γεωμετρία του ελλειψοειδούς της παραμόρφωσης στα μεταμορφωμένα πετρώματα της κεντρικής Κρήτης

Μιχαήλ, Ερασμία 03 November 2011 (has links)
Η Φυλλιτική-Χαλαζιτική ενότητα αποτελεί τμήμα των Εξωτερικών Ελληνίδων και έχει υποστεί μεταμόρφωση σε συνθήκες υψηλής πίεσης. Στην Κεντρική Κρήτη εμφανίζεται κυρίως στο βόρειο τμήμα του παραθύρου των Ταλαίων ορέων. Σκοπός της διπλωματικής εργασίας είναι να προσδιοριστεί η γεωμετρία του τριαξονικού ελλειψοειδούς της παραμόρφωσης και το ποσό της παραμόρφωσης στη Φυλλιτική-Χαλαζιτική ενότητα. Για το σκοπό αυτό συλλέχθηκαν 18 προσανατολισμένα δείγματα χαλαζιακής σύστασης και μετρήθηκαν ελλειπτικοί δείκτες της παραμόρφωσης σε δύο κάθετες μεταξύ τους τομές από κάθε δείγμα. Τα στοιχεία φανερώνουν ότι κατά την πλαστική φάση παραμόρφωσης D1 τα πετρώματα της Φυλλιτικής-Χαλαζιτικής ενότητας παραμορφώθηκαν κυρίως σε συνθήκες πλάτυνσης και σε μικρότερο βαθμό σε συνθήκες επίπεδης παραμόρφωσης. Επιπρόσθετα το ποσό της παραμόρφωσης έχει μια συστηματική και μη γραμμική αύξηση σε σχέση με την απόσταση από την επώθηση βάσης, ενώ ο τύπος του τριαξονικού ελλειψοειδούς δε συνδέεται με τη δομική θέση των δειγμάτων. / The Phyllite-Quartzite (PQ) unit is a part of the External Hellenides and has been subjected to a high pressure metamorphism. In Central Crete PQ unit mainly appears in the northern part of the Talaia window. The aim of this study is to determine the strain ellipsoid geometry and the intensity of deformation in the PQ unit. To do so 18 quartz-rich samples were collected, in which elliptical strain indicators were measured in two mutually perpendicular cross sections. Measurements show that during the D1 phase of the ductile deformation, rocks of the PQ unit were deformed mainly by flattening and secondary by plane strain conditions. Additionally, the amount of deformation shows systematic and non-linear increase relative to the distance of the Basal thrust while the type of strain ellipsoid is not related to the structural position of the samples in the PQ.
5

Fluid History of the Western Maryland Piedmont

LaFonte, Christopher John 27 July 2015 (has links)
No description available.
6

Estudo de massa cer?mica triaxial visando ? otimiza??o do ciclo de queima da ind?stria de cer?mica estrutural

Sales J?nior, Jos? Carlos Calado 31 May 2012 (has links)
Made available in DSpace on 2014-12-17T14:07:09Z (GMT). No. of bitstreams: 1 JoseCCSJ_TESE.pdf: 3857511 bytes, checksum: 1d384b3892d7aeac8dab23519e4bb09a (MD5) Previous issue date: 2012-05-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Over recent years the structural ceramics industry in Brazil has found a very favorable market for growth. However, difficulties related to productivity and product quality are partially inhibiting this possible growth. An alternative for trying to solve these problems and, thus, provide the pottery industry the feasibility of full development, is the substitution of firewood used in the burning process by natural gas. In order to contribute to this process of technological innovation, this paper studies the effect of co-use of ceramic phyllite and kaolin waste on the properties of a clay matrix, verifying the possible benefits that these raw materials can give to the final product, as well as the possibility of such materials to reduce the heat load necessary to obtain products with equal or superior quality. The study was divided into two steps: characterization of materials and study of formulations. Two clays, a phyllite and a residue of kaolin were characterized by the following techniques: laser granulometry, plasticity index by Atterberg limits, X-ray fluorescence, X-ray diffraction, mineralogical composition by Rietveld, thermogravimetric and differential thermal analysis. To study the formulations, specifically for evaluation of technological properties of the parts, was performed an experimental model that combined planning involving a mixture of three components (standard mass x phyllite x kaolin waste) and a 23 factorial design with central point associated with thermal processing parameters. The experiment was performed with restricted strip-plot randomization. In total, 13 compositional points were investigated within the following constraints: phyllite ≤ 20% by weight, kaolin waste ≤ 40% by weight, and standard mass ≥ 60% by weight. The thermal parameters were used at the following levels: 750 and 950 ?C to the firing temperature, 5 and 15 ?C/min at the heating rate, 15 and 45min to the baseline. The results showed that the introduction of phyllite and/or kaolin waste in ceramic body produced a number of benefits in properties of the final product, such as: decreased absorption of water, apparent porosity and linear retraction at burn; besides the increase in apparent specific mass and mechanical properties of parts. The best results were obtained in the compositional points where the sum of the levels of kaolin waste and phyllite was maximal (40% by weight), as well as conditions which were used in firing temperatures of 950 ?C. Regarding the prospect of savings in heat energy required to form the desired microstructure, the phyllite and the residue of kaolin, for having small particle sizes and constitutions mineralogical phases with the presence of fluxes, contributed to the optimization of the firing cycle. / Ao longo dos ?ltimos anos a ind?stria de cer?mica estrutural no Brasil vem encontrando um mercado bastante favor?vel para o crescimento. Entretanto dificuldades relacionadas ? produtividade e qualidade dos produtos est?o inibindo parcialmente esse poss?vel crescimento. Uma das alternativas para tentar solucionar esses problemas e, consequentemente, proporcionar ao setor oleiro a viabilidade do pleno desenvolvimento, ? a substitui??o da lenha utilizada no processo de queima pelo g?s natural. Com o intuito de contribuir nesse processo de inova??o tecnol?gica, o presente trabalho trata-se de um estudo do efeito da co-utiliza??o de filito cer?mico e res?duo de caulim sobre as propriedades de uma matriz argilosa, verificando os poss?veis benef?cios que esses materiais podem atribuir ao produto final, bem como, a possibilidade dessas mat?rias-primas reduzirem a carga t?rmica necess?ria para obten??o de produtos de igual ou superior qualidade. O trabalho foi divido em duas etapas: caracteriza??o dos materiais e estudo das formula??es. Duas argilas, um filito e um res?duo de caulim foram caracterizados atrav?s das seguintes t?cnicas: granulometria ? laser, ?ndice de plasticidade pelos limites Atterberg, fluoresc?ncia de raios X, difra??o de raios X, composi??o mineral?gica por Rietveld, an?lise termogravim?trica e an?lise t?rmica diferencial. Para o estudo das formula??es, mais especificamente para avalia??o das propriedades tecnol?gicas das pe?as, foi executado um modelo experimental que combinou um planejamento envolvendo mistura de tr?s componentes (massa padr?o x filito x res?duo de caulim) e um planejamento fatorial 23 com ponto central associado aos par?metros t?rmicos de processamento. A experimenta??o foi realizada com restri??o na aleatoriza??o por strip-plot. No total foram investigados 13 pontos composicionais dentro das seguintes restri??es: filito ≤ 20% em peso; res?duo de caulim ≤ 40% em peso; e massa padr?o ≥ 60% em peso. Os par?metros t?rmicos foram utilizados nos seguintes n?veis: 750 e 950 ?C para temperatura de queima; 5 e 15 ?C/min para a taxa de aquecimento; 15 e 45 min para o patamar. Os resultados obtidos demostraram que a introdu??o do filito e/ou res?duo de caulim na massa cer?mica produz uma s?rie de benef?cios nas propriedades do produto final, tais como: redu??o na absor??o de ?gua, porosidade aparente e retra??o linear de queima; al?m do aumento na massa espec?fica aparente e na resist?ncia mec?nica das pe?as. Os melhores resultados foram obtidos nos pontos composicionais em que a soma dos teores de filito e res?duo de caulim foi m?xima (40 % em peso), assim como, nas condi??es de queima em que foram utilizadas temperaturas de 950 ?C. Em rela??o ? perspectiva de economia na energia t?rmica necess?ria para forma??o da microestrutura desej?vel, o filito e o res?duo de caulim por apresentarem pequenos tamanhos de part?culas e constitui??es mineral?gicas com presen?a de fases fundentes, contribu?ram para a otimiza??o do ciclo de queima.
7

Περιβαλλοντική έρευνα των υδροφόρων οριζόντων του ΒΔ Λασιθίου με τη χρήση σπάνιων γαιών / Environmetal study of karstic aquifers in region NW Lasithi using rare earth elements

Πυτικάκης, Εμμανουήλ 28 June 2007 (has links)
Στην περιοχή του ΒΔ Λασιθίου απαντώνται οι γεωλογικοί σχηματισμοί των πλακώδων ασβεστόλιθων και των ασβεστόλιθων της ζώνης Τρίπολης. οι σχηματισμοί αυτοί είναι έντονα καρστικοποιημένοι και αποτελούν τους κύριους υδροφόρους της περιοχής έρευνας. Μεταξύ των δύο υδροφόρων, στις περιοχές Νεάπολης και Ποτάμων παρεμβάλλονται τα αδιαπέρατα στρώματα των Φυλλιτών-Χαλαζιτών. Ο υδροφόρος που αναπτύσσεται στους ανθρακικούς σχηματισμούς της ζώνης Τρίπολης κατηγοριοποιείται σε τρεις ζώνες σύμφωνα με τον υδροχημικό χαρακτήρα του υπόγειου νερού. η πρώτη ζώνη αποτελείται από τις περιοχές τροφοδοσίας του υδροφόρου (Δράσι, Άγιος Κωνσταντίνος και Ποτάμοι) με εξαίρετη ποιότητα νερού, η δεύτερη ζώνη συνιστάται από τις περιοχές των Λακωνίων και Κριτσάς, όπου το νερό του υδροφόρου έχει επηρεαστεί από τη διείσδυση του θαλασσινού νερού. Τέλος, η τρίτη ζώνη αποτελείται από τις παράκτιες περιοχές του Αγίου Νικολάου και Αλμυρού με έντονη επιρροή από την διαδικασία της υφαλμύρινσης Ο υδροφόρος που αναπτύσσεται στους Πλακώδεις ασβεστόλιθους είναι ανοικτός στην θάλασσα και επηρεάζεται στο σύνολο του από την διείσδυση του θαλασσινού νερού. Με τη χρήση των κανονικοποιημένων διαγραμμάτων των σπάνιων γαιών, τόσο σε δείγματα πετρωμάτων όσο και σε δείγματα νερού προέκυψε ότι οι δύο καρστικοί υδροφόροι επικοινωνούν υδραυλικά στην περιοχή του Δάμακα Β-ΒΔ του Αγίου Νικολάου. / The region of NW Lasithi is dominated by plattenkalk and Tripoli’s zone limestones. These geological formations are characterized by karst and host the main aquifers of study area. Impermeable layers of phyllite-quartzite formation occur between these limestone formations, in the areas of Neapolis and Potami. The aquifer hosted by the carbonate formations of Tripoli’s zone is divided in three zones based on the hydrochemical characteristics of the underground water. The first zone includes the areas Drasi, Agios Konstantinos and Potami that are the sources of the aquifer, with excellent water quality. The second zone consists of the areas Lakonia and Kritsa, in which the underground water have been infiltrated by sea water. Finally the third consists of the coastal zones of Agios Nikolaos and Almyros, which have been affected by the process of brackish water. The aquifer hosted by the plattenkalk limestones is open to the sea and is affected by the intrusion of sea water. It can be shown, using normalized rare earth element diagrams of analyses of both rocks and underground waters, that the two karstified aquifers communicate hydraulically in the area of Damakas, N-NW of city Agios Nikolaos.

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