Capillary Absorption
Mostrando 13-24 de 56 artigos, teses e dissertações.
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13. Avaliação das propriedades de transporte de massa contendo adições minerais / Evaluation of the mass transport containing mineral admixtures
A durabilidade das estruturas de concreto armado é prejudicada pela ação deteriorante da penetração de substâncias na forma de gases, vapores e líquidos através de poros e fissuras. Sabe-se que a água, tanto no seu estado puro ou com íons dissolvidos, como os cloretos, sulfato, dióxido de carbono ou oxigênio, pode comprometer a durabilidade das e
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/10/2009
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14. Performance analysis of magnesium phosphate cement mortar containing grinding dust
Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP), which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight) of gr
Materials Research. Publicado em: 2009-03
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15. Avaliação das propriedades de transporte de massa contendo adições minerais / Evaluation of the mass transport containing mineral admixtures
The durability of reinforced concrete structures is damaged by the degrading action of the penetration of substances in the form of gases, vapors and liquids through the pores and cracks. It is known that water both in its pure form or containing dissolved ions such as chloride, sulphate, carbon dioxide or oxygen ions, can compromise the durability of concre
Publicado em: 2009
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16. Toxicidade subcrônica de lambaris Astyanax aff. bimaculatus expostos ao zinco / Subchronic toxicity in Astyanax aff. bimaculatus exposed to zinc.
Many metals occur naturally in aquatic environments and are classified as pollutants only when added by men in sufficient amounts to produce deleterious effects on organisms. Among these metals already existent on the aquatic environment it can be mentioned zinc (Zn) which is an essential element for living beings. In high concentrations, zinc can become tox
Publicado em: 2009
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17. CARBONATION AND CAPILLARY ABSORPTION IN CONCRETES OF WHITE PORTLAND CEMENT WITH HIGH CONTENTS OF BLAST FURNACE SLAG AND CHEMICAL ACTIVATORS / CARBONATAÇÃO E ABSORÇÃO CAPILAR EM CONCRETOS DE CIMENTO PORTLAND BRANCO COM ALTOS TEORES DE ADIÇÃO DE ESCÓRIA DE ALTO FORNO E ATIVADOR QUÍMICO
The carbonation phenomenon, reaction between CO2 from the atmosphere in the presence of humidity with the Portland cement hydration products, induces pH reduction to levels that can cause the elimination of steels protective layer, enabling the corrosion mechanism of the steel structure to start.. This is one of the main pathologies in the reinforced concret
Publicado em: 2008
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18. Influência da substituição do agregado miúdo natural por agregado reciclado fino em propriedades de argamassas e concretos
Construction and demolition waste (CDW) recycling has been a good alternative to reducing the impact caused by the consumption and high demand of raw materials for civil construction. In this sense, it has been tried to incorporate those wastes in the production of concrete and decrease strength mortar, what would increase its potential use. This study was d
Publicado em: 2008
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19. PERCOLAÇÃO DE ÁGUA EM CONCRETOS COM ELEVADOS TEORES DE ESCORIA E CINZA VOLANTE COM ADIÇÃO DE CAL / WATER PERCOLATION IN PRISMS OF CONCRETE WITH HIGH GRADES OF SLAG AND FLY ASH WITH ADDITION LIME
The study of concrete structures durability necessarily passes by the study of covercrete and by the understanding of the factors that affect the features of this superficial layer. The use of high contents of mineral addictions on the concrete influences meaningfully the resistance of the covering layer to the chemical attack and on the pores structure. Thi
Publicado em: 2007
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20. Aspectos analíticos em TS-FF-AAS : estudo de interferências e aplicação para a determinação de metais em vinhos e sucos / Analytical aspects of ts-ff-aas: study of interferences and application for determinations of metals in wines and grape juices
In this work, it was evaluated the effects of interferences caused by major and minor constituents on Co, Cu and Mn atomized by flame atomic absorption spectrometry (FAAS) and by thermospray flame furnace atomic absorption spectrometry (TS-FFAAS). The main concomitants were chosen according to the typical concentrations found in foods and beverages. The liqu
Publicado em: 2007
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21. AVALIAÇÃO DO DESEMPENHO DE CONCRETOS COM ADIÇÕES MINERAIS QUANTO À CORROSÃO DAS ARMADURAS INDUZIDA POR CLORETOS / Performance evaluation of concretes content with mineral additions in relation to the reinforcing steels corrosion induced by chlorides
The present work aims to study the performance of concrete with regard to the action of chloride ions, evaluating the influence of both mineral additions and water/binder ratio (w/b), considering kinetic and thermodynamic aspects of the corrosive phenomenon. A experimental research was carried out considering the following variables: the presence of mineral
Publicado em: 2007
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22. Potencial de aproveitamento de resíduos de caulim paraibano para o desenvolvimento de argamassas de múltuplo uso. / Potential use of waste kaolin Paraiba for the development of multiple-use mortars.
In Paraíba, the industry of the kaolin, an activity of great importance to the State and local producers, generating large amounts of waste that is landfilled, impacting the environment. The National Council on the Environment (CONAMA) has been made responsible for waste management to their generators. This residue does not have recycling technology known d
Publicado em: 2007
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23. Reciclagem do resíduo de cromo da indústria do curtume como pigmentos cerâmicos. / Recycling of chromium waste of leather industry as ceramic pigments.
In this work, an alternative for recycling the chromium waste from the leather industry, incorporating it to formulations of ceramic pigments was studied. Firstly, the characterization of chromium waste was performed, as well as the extraction of soluble salts, chlorides, sulfates, ad carbonates. After that, the calcination, for the elimination of the organi
Publicado em: 2006
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24. APERFEIÇOAMENTO E APLICAÇÕES DE UMA METODOLOGIA PARA ANÁLISE DE ESPECIAÇÃO DE ARSÊNIO POR ELETROFORESE CAPILAR COM DETECTOR DE ICPMS / IMPROVEMENTS AND APPLICATIONS OF A METHODOLOGY FOR THE SPECIATION ANALYSIS OF ARSENIC USING CAPILLARY ELECTROPHORESIS WITH ICPMS DETECTOR
Capillary electrophoresis (CE) is a well established separation technique for the study of elemental speciation, however, its low electroosmotic flow nL min(-1) restricts its application in many studies in which low detection limits are required. For this reason, the study of CE coupling (hyphenation) to more sensitive detectors is of great relevance. This w
Publicado em: 2006