116 resultados para Oxidação eletrolítica assistida por plasmas


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Ciências Biológicas (Zoologia) - IBB

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O objeto da presente patente é um reator fotoeletrocatalítico operando com eletrodos nanoporosos ou nanotubulares de Ti/TiO~ 2~ como fotoanodos, uma rede de platina como cátodo para oxidação fotoeletrocatalítica de efluentes coloridos, sob densidade de corrente constante e irradiação de luz UV, utilizado no tratamento de águas de rejeito contendo corantes ácidos, básicos, dispersos, reativos e agentes dispersantes e efluentes coletados de indústrias têxteis. Ambos os eletrodos mostraram uma performance acima dos métodos usuais removendo não apenas a coloração, mas processando grande mineralização dos diversos tipos de corantes, surfactantes etc. em efluentes da industria têxtil.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Information retrieval has been much discussed within Information Science lately. The search for quality information compatible with the users needs became the object of constant research.Using the Internet as a source of dissemination of knowledge has suggested new models of information storage, such as digital repositories, which have been used in academic research as the main form of autoarchiving and disseminating information, but with an information structure that suggests better descriptions of resources and hence better retrieval.Thus the objective is to improve the process of information retrieval, presenting a proposal for a structural model in the context of the semantic web, addressing the use of web 2.0 and web 3.0 in digital repositories, enabling semantic retrieval of information through building a data layer called Iterative Representation.The present study is characterized as descriptive and analytical, based on document analysis, divided into two parts: the first, characterized by direct observation of non-participatory tools that implement digital repositories, as well as digital repositories already instantiated, and the second with scanning feature, which suggests an innovative model for repositories, with the use of structures of knowledge representation and user participation in building a vocabulary domain. The model suggested and proposed ─ Iterative Representation ─ will allow to tailor the digital repositories using Folksonomy and also controlled vocabulary of the field in order to generate a data layer iterative, which allows feedback information, and semantic retrieval of information, through the structural model designed for repositories. The suggested model resulted in the formulation of the thesis that through Iterative Representation it is possible to establish a process of semantic retrieval of information in digital repositories.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The present work assessment materials can be used as fuel cells electrocatalysts. The alkaline fuel cell though was less studied, has some advantages compared to the acid configuration. The materials assesment were Au polycrystalline and intermetallics ordered phases of AuIn, AuSn and AuSb2. Your electrocatalytic properties were studied across cyclic voltametry and chronoamperometry techniques in Sodium Hydroxide 0,15M and Metanol 0,15M solution. The results obtained show a more efficiency to intermetallic AuIn as electrocatalyst for the oxidation reaction of methanol in alkaline medium, it showed high levels of current density and on set potential less positive compared to Au polycrystalline. The intermetallic AuSn showed activity just higher concentrations of methanol. Except AuSb2, who represented himself unstable in alkaline media, the intermetallics AuIn and AuSn present a promising future as anode materials for the oxidation in alkaline medium

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This paper presents the study on the application of the electrolytic plasma for surface treatment of aluminum. A bibliographical study on the material of interest was preliminarily performed and later designed and built an electrolytic cell, including the excitation source. Unlike conventional electrolysis process, the plasma assisted carry on in the non-linear region of characteristic current/voltage curve. Therefore it requires for the on set of the process that the power supply operates on harder conditions than those on high current process. The plasma produced during the present investigation has temperatures in the range o 6,0.10 3 -7,0 .10 3 K, well above those found in conventional chemical process. It also shows a particular dynamic to promote changes on surface and to produce new materials. The plasma is generated by microdischarge in vapor or gas bubbles involved in physic-chemical processes in electrode regions of the electrolytic cell. The electrode material was the aluminum (7075). The Process Electrolytic Plasma Processing (EPP) is sensitive to various parameters such as operating voltage, current density, electrolyte, concentration of electrolyte, geometry of reactor, temperature of electrolytic solution and dynamic of the fluid in the cell. The experiments were carried on in order to find parameters for a stable abd steady operation. The choice for the electrolytic was silicate/alkali solution in various concentrations to operate in various voltage as well. Plasma was produced on negative (cathode) and positive (anode) electrode, in specific conditions. A stable operation on the cathode process was obtained with low concentration of the electrolytic in aqueous solution, current density around 250V effective voltage. For the evolution of plasma in anodic process it was required higher concentrations and higher... (Complete abstract click electronic access below)

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Mass spectrometry is a diagnosis that can aid in the understanding of the kinetics of chemical plasma environment. Through this you can get information about some species present in the environment and make inferences about the behavior of the plasma when parameters such as pressure and applied power changes. When analyzed plasmas generated by the discharge of argon and diglyme (both individually and mixtures of them in various proportions) could be found conditions in which the plasma behavior was different from what is often found in the literature. By the end some peculiar characteristics of plasmas generated by mixing argon / diglyme were raised and it was found that the noble gas is a good mediator of physical and chemical reactions that occur in the environment, and help in the understanding of chemical kinetics. Therefore mass spectrometry was shown highly important tool for the study of plasma environment

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Melatonin is an endoleamine that has anti-inflammatory, immunomodulating and antioxidants properties. But there is a contradiction between the antioxidant effects of melatonin and glutathione (GSH). Therefore, the main objective of this work was to study the effect of melatonin on the oxidation of GSH and the effect of GSH on the oxidation of melatonin by peroxyl radicals generated by thermolysis of 2,2 -Azobis(2- amino-propane)-dihydrochloride (AAPH). The influence of the reaction conditions and the identity of the products of oxidation were also studied. The main products obtained during the oxidation of melatonin were its monohydroxylated derivative and N1-acetyl- N2-formyl-5-methoxykynuramine (AFMK), which is the product obtained by oxidative cleavage of the melatonin indole ring. By studying the buffer type, pH and the presence or absence of dissolved oxygen in the reaction system, it was observed that, the yield of AFMK was higher when the pH or the concentration of oxygen was increased. Comparing the reactivity of both molecules GSH and melatonin, it can be seen that intermediates radicals generated during the oxidation of melatonin are able to oxidize GSH itself. We propose that this chemical property could justify the recent reports that demonstrated the inability of melatonin to inhibit the oxidation of GSH in cells