Hydrogen Ion Concentration
Mostrando 13-24 de 149 artigos, teses e dissertações.
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13. TEMPORAL EVALUATION OF LIMNOLOGIC VARIABLES AT RODOLFO COSTA E SILVA RESERVOIR - RS, AND THE LAND USE IN THE DAM UP AREA / AVALIAÇÃO TEMPORAL DE VARIÁVEIS LIMNOLÓGICAS DO RESERVATÓRIO RODOLFO COSTA E SILVA - RS, E O USO DA TERRA NA ÁREA DE CAPTAÇÃO
The relationship between man and environment initially happens in a natural way. After a while, there is an accelerated populational growth, and new technology comes, which intensifies the human actions both in the terrestrial environment and in the aquatic one, imposing, therefore, unbalance in the relation man-nature. Thus, quantitative and qualitatively,
Publicado em: 2008
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14. Influence of different formulations of bleaching agents on enamel and dentin physical and chemical properties / Influencia de diferentes formulações de agentes clareadores nas propriedades fisicas e quimicas do esmalte e dentina
Section A: Effects of bleaching agents on dental enamel Since the introduction of the nightguard vital bleaching technique using 10% carbamide peroxide (10% CP), reports have evaluated the effects of bleaching agents on human enamel. Evidences show that CP is able to alter the composition and morphology of enamel substrate. In order to reduce the adverse eff
Publicado em: 2007
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15. Estudo voltamétrico da interação dos íons Zn2+, Cu2+, Cd2+ e Pb2+ com a enzima catalase
Catalase (CAT), which is an important enzyme that catalyzes the decomposition of hydrogen peroxide (H O ) to water (H O) and oxygen (O ), contains 2 2 2 2 some metal binding sites (Cys, His). The binding of metal ions to CAT can change or stabilize its secondary structure, resulting in its inhibition or activation, respectively. The inhibition of CAT, which
Publicado em: 2007
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16. Surface treatments of a iron aloy by nitrogen ions / Tratamentos de superficies de uma liga ferrosa por ions de nitrogenio
The objective of this project is to study processes of plasma surface treatment with special emphasis to the differences these techniques might show in relation to others, looking forward to understand the process from surface phenomena. Two kinds of surface treatment have been studied, including three different techniques: ion beam nitriding, pulsed plasma
Publicado em: 2006
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17. Investigação da formação e efeitos do clorato sobre a reação de desprendimento de hidrogênio no processo de cloro-soda com tecnologia de diafragma / Formation and effecters of chlorate over hydrogen evolutoin in clhorine-alkalis diaphragm process
In this work, the formation and effects of chlorate ion were studied over hydrogen evolution reaction (HER), focusing for the chlorine and alkalis production by diaphragm process, using a pilot and bench cells, respectively. Studies in pilot cell revealed that chlorate formation is dependent of NaOH concentration in liquor and brine dwelling time. It was als
Publicado em: 2006
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18. Respostas à acidez em células de tabaco (Nicotiana tabacum) cv. BY-2 em diferentes estados de sensibilidade / The response of tobacco (Nicotina tabacum) cv. BY-2 cells to low pH at different stages of sensitivity
Acid soils account for about 40 % of the surface area of the world and are one of the major factors limiting plant productivity. In Brazil, these soils comprise roughly two-thirds of its total territory. In general, soil acidity is detrimental because it limits the depth of the root system, increasing susceptibility to drought and decreasing the use of nutri
Publicado em: 2006
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19. SÍNTESE, ESTRUTURAS DE TRIAZENO 1-ÓXIDO E COMPLEXO DE K+, E AVALIAÇÃO DA ATIVIDADE BIOLÓGICA DE 1-METILTRIAZENOS 1-ÓXIDO E 1,3-BIS(ARIL)TRIAZENOS / SYNTHESIS, STRUCTURE OF TRIAZENE 1-OXIDE AND COMPLEX OF K+, AND EVALUTION OF BIOLOGICAL ACTIVITY OF 1-METILTRIAZENES 1-OXIDE AND 1,3-BIS(ARIL)TRIAZENES
This work is associated with the crystal and molecular structure analysis of two free triazene 1-oxide molecules and a complex with K+ involving a p-carboxyfenil-substituted single protonated triazene 1-oxide ligand. 1-metil-3-(p-carboxyphenyl)triazene 1-oxide (1) crystallizes in the monoclinic system, space group C2/c, with cell parameters a = 27.2046(8) Å
Publicado em: 2005
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20. ERVA-MATE E ATIVIDADE ANTIOXIDANTE / YERBA-MATE AND ANTIOXIDANT ACTIVITY
Ilex paraguariensis Saint Hilaire (Aquifoliaceae), popularly known as yerba-mate, is a native species of South America and has its area of natural occurrence restricted to Brazil, Paraguay and Argentina. It is a product that still has a lot to be improved, mainly, in terms of its industrial uses, in international level. Antioxidants are composts that work as
Publicado em: 2005
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21. Estudo das propriedades termomecanicas e estruturais de filmes finos amorfos de carbono e nitretos de carbono / Study of the thermomechanical and structural properties in amorphous carbon and carbon nitride
In this work, we studied thenno mechanical and structural properties of hydrogenated amorphous carbon (a-C: H), hydrogenated carbon nitride (a-C:H:Nx) and carbon nitride (a-C:Nx) thin films. Two techniques were used to prepare the samples: glow discharge for depositing hydrogenated amorphous carbon (a-C:H) and carbon nitride (a-C:H:Nx) and ion beam assisting
Publicado em: 2004
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22. TRATAMENTO OXIDATIVO DE EFLUENTES CONTENDO HIDRAZINA / TREATEMENT WASTEWATER EFFLUENTS CONTAINING HYDRAZINE
In Brazil, the use of energy produced by power plant generators is in expansion. Power plants use large quantities of water and chemical products that after use end up in effluents. Hydrazine is used in water systems for corrosion control, because of its excelents oxygen scavenging capacity. The present work was conducted to study the treatment of effluents
Publicado em: 2003
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23. Magnetic properties of gadolinium-doped amorphous silicon films
Electron spin resonance (ESR) and dc-magnetization experiments have been performed in Gd-doped amorphous (a-)silicon films. The films were deposited by the cosputtering technique following different conditions rendering samples with varying Gd and hydrogen concentrations. In addition to films with different contents of impurities and, in order to probe the i
Brazilian Journal of Physics. Publicado em: 2002-06
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24. Effect of hydrogen peroxide and chlorite ion residual on an activated sludge system of bleached kraft pulp mills / Efeito do residual de peróxido de hidrogênio e do íon clorito em um sistema de lodos ativados de indústrias de celulose kraft branqueada
Hydrogen peroxide and chlorine dioxide has been largelly used in bleaching plants of bleached kraft pulp mills, to delignify and to whiten the pulp, giving to it high quality, specially brightness. However, in some transient situations, such changes in the raw material, in the bleaching sequences, or in production, high charges of oxidants are required to ma
Publicado em: 2002