Rock Testing
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Influence of water/powder ratio in the mineral and synthetic casts
AIM: To evaluate the influence of varying the water/powder ratio on the compressive strength of type IV mineral and synthetic casts. METHODS: Four commercial brands of type IV mineral and synthetic casts were evaluated: Durone, Herostone, Fuji Rock, and Elite Rock. Ninety-six test samples were prepared from a silicone matrix, according to ADA's standar
Braz. J. Oral Sci.. Publicado em: 2014-09
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2. Mechanical performance of encapsulated restorative glass-ionomer cements for use with Atraumatic Restorative Treatment (ART)
The Atraumatic Restorative Treatment (ART) approach was suggested to be a suitable method to treat enamel and dentine carious lesions in patients with disabilities. The use of a restorative glass-ionomer with optimal mechanical properties is, therefore, very important. Objective To test the null-hypotheses that no difference in diametral tensile, compressiv
J. Appl. Oral Sci.. Publicado em: 2013-06
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3. Linear dimensional change, compressive strength and detail reproduction in type IV dental stone dried at room temperature and in a microwave oven
The type IV dental stone is widely used for the fabrication of dyes and master casts for fixed and removable partial prostheses. It is typically normal to wait at least 24 hours for the casts to dry prior to beginning the laboratory procedures. The waiting time has been shown to be greatly reduced by using microwave drying. OBJECTIVE: This study evaluated th
J. Appl. Oral Sci.. Publicado em: 2012-10
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4. Estudo de mecanismos de deformação lenta da gipsita bandada da Chapada do Araripe em ensaios de fluência monitorados por emissão acústica / Study of slow deformation mechanisms of the banded gypsum rock of the Chapada do Araripe in creep tests monitored by acoustic emission
Experimental studies by several authors have shown some of the key deformation mechanisms in gypsum, such as plastic flow and pressure dissolution. Even so, there is still sparse knowledge about the mechanical behavior of natural gypsum rocks. Creep mechanisms of the banded gypsum rock of Santana Formation from the Chapada do Araripe (Santana Formation) in c
Publicado em: 2009
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5. Análise de estabilidade de taludes em solos de alteração de rochas metamórficas do Quadrilátero Ferrífero / Slope stability analysis in soils of alteration of metamorfic rocks of Quadrilátero Ferrífero
The present work has the aim of improve the knowledge on the mechanical behavior of several materials occurring in the slopes of the Pico mine, in Quadrilátero Ferrífero area, Minas Gerais State. Triaxiais tests and direct shear tests of undisturbed samples collected in situ were performed in order to obtain strength parameters under several loading condit
Publicado em: 2006
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6. Ensaios não convencionais para determinação da tenacidade à fratura em rochas: análise e comparação / Non-conventional tests for determining the fracture toughness in rocks: analysis and comparison
Since early 1970 s new fracture mechanics concepts have been developed to explain rock fracture behavior. Fracture toughness has been measured and considered as an important intrinsic property of rock indicating the magnitude of fracture strength or its ability to resist crack propagation. Rock fracture mechanics has been widely applied to tectonics, energy
Publicado em: 2004
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7. DESENVOLVIMENTO DE EQUIPAMENTO E METODOLOGIA DE TESTES PARA AVALIAÇÃO DA INTERAÇÃO FOLHELHO-FLUIDO DE PERFURAÇÃO / DEVELOPMENT OF EQUIPMENT AND TESTING METHODOLOGY TO EVALUATE ROCK-DRILLING FLUID INTERACTION
The drilling of oil wells through shales, which constitute the majority of rocks in the stratigraphic column, may present instability problems due to physico-chemicals interactions between the drilling fluids and these rocks. The costs associated to the solution of these problems are very high and, depending upon the intensity of these problems, wells can be
Publicado em: 2003
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8. DEVELOPMENT OF A TRIAXIAL CELL FOR LABORATORY TESTS OF ROCKS / DESENVOLVIMENTO DE UMA CÉLULA PARA ENSAIOS TRIAXIAIS EM ROCHA / DESARROLLO DE UNA CÉLULA PARA ENSAYOS TRIAXIALES EN ROCAS
Rock masses are submitted to biaxial and triaxial states of stress. Deformability and strength properties of rocks under such conditions are essential data for calculating bearing capacity of foundations, design of dams, mining excavations, oil exploration, tunnelling etc. For these purposes, laboratory and in situ tests are of great importance. Studying roc
Publicado em: 1997
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9. Analise de parametros de tenacidade ao fraturamento de concretos obtidos em ensaios de flexão de vigas
Concrete is a composite that behaves inelasticaly, with failure characterized by softening. Crack in this kind of material is said to be cohesive. The development of an inelastic process zone ahead of the crack front as well as the formation of the cohesive interface, at laboratory level, are directly infIuenced by the specimen Size. The effect of the specim
Publicado em: 1997
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10. Modelo composicional de reservatorios com formulação totalmente implicita
This work describes an isotermal and two-dimensional fully implicit compositional model, which has been developed to the moddelling of retrograde gas condensate and volatile oil reservoirs. The model considers oil, gas and water phases, and may be applied to either cartesian (x-y) or cylindrical (r-z) grids. Water is considered to be immobile and slightly co
Publicado em: 1990
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11. Aesthesiometric threshold changes over the course of a workshift in miners exposed to hand-arm vibration.
The objective of this study was to investigate whether aesthesiometric threshold changes occur over the course of a workshift in vibration exposed hard rock miners relative to workers unexposed to vibration during the shift. The subjects were 99 miners and 40 smelter workers; four subjects declined to participate and nine were excluded from the analysis beca
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12. Genotypic and Phenotypic Characterization of “Streptococcus milleri” Group Isolates from a Veterans Administration Hospital Population
Because identification of the species within the “Streptococcus milleri” group is difficult for the clinical laboratory as the species share overlapping phenotypic characteristics, we wished to confirm biochemical identification with identification by 16S rRNA gene sequence analysis. Ninety-four clinical isolates previously identified as the “Streptoco
American Society for Microbiology.