918 resultados para Shell molding (Founding)
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De Gaulle, founder of the Fifth French Republic, cherished the notion that the president of the Republic could somehow stand above party politics. In many ways this belief shaped the early institutional configuration of the new Republic. Party politics, however, rapidly reached the presidency, especially with the move, under the constitutional reform of 1962, to direct election of the president. This article charts the development of France's 'political constitution' and the relationship between president and parties over the first decade of the Fifth Republic. It finds that although the presidency became the prime goal of party political competition, the (often dysfunctional) illusion of a head of state above politics continues to shape the behaviour and perceptions of French presidents.
A study of the chemical and physical properties of cashew nut shell ash for use in cement materials.
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A study of the chemical and physical properties of cashew nut shell ash for use in cement materials. Ash occupies a prominent place among agro-industrial wastes, as it is derived from energy generation processes. Several types of ash have pozzolanic reactivity, and might be used as replacement material for cement, resulting in less energy waste and lower cost. This work aimed to investigate the physical and chemical properties of the cashew nut shell ash (CNSA), by performing the following measurement tests: chemical analysis, bulk density, specific mass, leaching and solubilization process, X-ray diffraction (XrD), specific surface area (BET) and pozzolanicity analysis with cement and lime. The results indicate a low reactivity of CNSA and the presence of heavy metals, alkalis and phenol.
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Purpose - The purpose of this paper is to develop a novel unstructured simulation approach for injection molding processes described by the Hele-Shaw model. Design/methodology/approach - The scheme involves dual dynamic meshes with active and inactive cells determined from an initial background pointset. The quasi-static pressure solution in each timestep for this evolving unstructured mesh system is approximated using a control volume finite element method formulation coupled to a corresponding modified volume of fluid method. The flow is considered to be isothermal and non-Newtonian. Findings - Supporting numerical tests and performance studies for polystyrene described by Carreau, Cross, Ellis and Power-law fluid models are conducted. Results for the present method are shown to be comparable to those from other methods for both Newtonian fluid and polystyrene fluid injected in different mold geometries. Research limitations/implications - With respect to the methodology, the background pointset infers a mesh that is dynamically reconstructed here, and there are a number of efficiency issues and improvements that would be relevant to industrial applications. For instance, one can use the pointset to construct special bases and invoke a so-called ""meshless"" scheme using the basis. This would require some interesting strategies to deal with the dynamic point enrichment of the moving front that could benefit from the present front treatment strategy. There are also issues related to mass conservation and fill-time errors that might be addressed by introducing suitable projections. The general question of ""rate of convergence"" of these schemes requires analysis. Numerical results here suggest first-order accuracy and are consistent with the approximations made, but theoretical results are not available yet for these methods. Originality/value - This novel unstructured simulation approach involves dual meshes with active and inactive cells determined from an initial background pointset: local active dual patches are constructed ""on-the-fly"" for each ""active point"" to form a dynamic virtual mesh of active elements that evolves with the moving interface.
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This paper discusses the ongoing ethnoarchaeological research carried out in Yamana shell middens of Tierra del Fuego. Ethnoarchaeology is used in this research as a tool to improve the archaeological methodology by testing it against anthropological, ethnographical and ethnological sources for achieving more accurate reconstructions of past societies. The ethnographical/ethnological information also is coupled with an experimental approach devised to understand physical and social processes, such as site formation processes and resource use and management. Specifically, this experimental approach was applied to the archaeological sites Tunel VII and Lanashuaia I (Tierra del Fuego, Argentina). (C) 2011 Elsevier Ltd and INQUA. All rights reserved.
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Commonly used in archaeological contexts, micromorphology did not see a parallel advance in the field of experimental archaeology. Drawing from early work conducted in the 1990`s on ethnohistoric sites in the Beagle Channel, we analyze a set of 25 thin sections taken from control features and experimental tests. The control features include animal pathways and environmental contexts (beach samples, forest litter, soils from the proximities of archaeological sites), while the experimental samples comprise anthropic structures, such as hearths, and valves of Mytilus edulis (the most important component of shell middens in the region) heated from 200 degrees C to 800 degrees C. Their micromorphological study constitutes a modern analogue to assist archaeologists studying site formation and ethnographical settings in cold climates, with particular emphasis on shell midden contexts. (c) 2010 Elsevier Ltd. All rights reserved.
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We study the effects of population size in the Peck-Shell analysis of bank runs. We find that a contract featuring equal-treatment for almost all depositors of the same type approximates the optimum. Because the approximation also satisfies Green-Lin incentive constraints, when the planner discloses positions in the queue, welfare in these alternative specifications are sandwiched. Disclosure, however, it is not needed since our approximating contract is not subject to runs.
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The present work has as objective the development of ceramic pigments based in iron oxides and cobalt through the polymeric precursor method, as well as study their characteristics and properties using methods of physical, chemical, morphological and optical characterizations.In this work was used iron nitrate, and cobalt citrate as precursor and nanometer silica as a matrix. The synthesis was based on dissolving the citric acid as complexing agent, addition of metal oxides, such as chromophores ions and polymerization with ethylene glycol. The powder obtained has undergone pre-ignition, breakdown and thermal treatments at different calcination temperatures (700 °C, 800 °C, 900 °C, 1000 °C and 1100 °C). Thermogravimetric analyzes were performed (BT) and Differential Thermal Analysis (DTA), in order to evaluate the term decomposition of samples, beyond characterization by techniques such as BET, which classified as microporous materials samples calcined at 700 ° C, 800 º C and 900 º C and non-porous when annealed at 1000 ° C and 1100 º C, X-ray diffraction (XRD), which identified the formation of two crystalline phases, the Cobalt Ferrite (CoFe2O4) and Cristobalite (SiO2), Scanning Electron Microscopy (SEM) revealed the formation of agglomerates of particles slightly rounded;and Analysis of Colorimetry, temperature of 700 °C, 800 °C and 900 °C showed a brown color and 1000 °C and 1100 °C violet
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The concrete offshore platforms, which are subjected a several loading combinations and, thus, requires an analysis more generic possible, can be designed using the concepts adopted to shell elements, but the resistance must be verify in particular cross-sections to shear forces. This work about design of shell elements will be make using the three-layer shell theory. The elements are subject to combined loading of membrane and plate, totalizing eight components of internal forces, which are three membrane forces, three moments (two out-of-plane bending moments and one in-plane, or torsion, moment) and two shear forces. The design method adopted, utilizing the iterative process proposed by Lourenco & Figueiras (1993) obtained from equations of equilibrium developed by Gupta (1896) , will be compared to results of experimentally tested shell elements found in the literature using the program DIANA.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The occurrence of subfossil material in bottom sediments of Couve Island, Ubatuba region, São Paulo State, is confirmed. The analyzed material consists of a bivalve shell that was dated by the electron spin resonance technique. By the additive irradiation method an archaeological absorbed dose of (25 +/- 5) Gy was obtained and calibration with other dating works in the same area allows the inference of an age of (25 +/- 5) x 10(2) years. The importance of this finding and its paleoecological implications could contribute to elucidating the nature of short-term environmental changes in the Brazilian coastline during the Holocene, as well as becoming an important tool to the understanding of the distribution and biological aspects of the bivalve fauna. (C) 2002 Elsevier B.V. Ltd. All rights reserved.
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This study aimed to characterize the populational structure of Clibanarius vittatus (Bosc, 1802), as well as to determine the morphometric relations between the animal's size and the variables: length of their chelar propodus and the size of the shell opening. C. vittatus is a relatively abundant pagurid on the west Atlantic coast, it occurs in the intertidal region from 38 degrees N to 28 degrees S. The animals in this study were randomly sampled every month on the Paranapu (a) over tilde Beach (46 degrees 23' S e 23 degrees 59' W), S (a) over tilde $ o Vicente (SP), Brazil. The biometrics data were adjusted to the power equation (y = ax(b)), by means of the minimum square method. A total of 427 individuals were collected. The size of the cephalothoraxic shield ranged from 2.5 to 12.7 mm, evidencing a representative sample of the population. The of most commonly genus of Gastropoda shells occupied by the hermits was Thais (97,26%). In relation to the morphometric analyses performed, it was observed a positive correlation between the animal size and the variables length of the chelar propodus and the size of the shells.
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The objective of this study is to investigate the patterns of shell utilization in Petrochirus diogenes in the Ubatuba region, SP, Brazil. Hermit crabs were obtained from 1993 to 1996 with the aid of a shrimp fishery boat equipped with two double-rigged trawling nets. Shells were identified and weighed, and their maximum aperture width was measured. Hermit crabs were weighed, and their shield length was recorded. A total of 634 P. diogenes specimens, occupying shells of 12 gastropod species, was obtained. The shells of Tonna galea, Zidona dufresnei and Strombus pugilis were the most frequently occupied, the first marked by its larger aperture width and lower average weight. Small hermit crabs inhabited a wide variety of gastropod shells due to their higher availability. However, the utilization of T. galea shells became predominant as the crabs attained larger sizes. Differences in weight and aperture width are known to encourage certain shell utilization patterns and may affect growth and reproduction of hermit crabs.