80 resultados para Gasolina - Teses
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
VITULLO, Nadia Aurora Vanti. Avaliação do banco de dissertações e teses da Associação Brasileira de Antropologia: uma análise cienciométrica. 2001. 143 f. Dissertaçao (Mestrado) - Curso de Mestrado em Biblioteconomia e Ciência da Informação, Pontifícia Universidade Católica de Campinas, Campinas, 2001.
Resumo:
OLIVEIRA, Raimundo Muniz de. Biblioteca digital de teses e dissertaçoes: uma referencia fundamental. In: CINFORM ENCONTRO NACIONAL DE ENSINO E PESQUISA DA INFORMAÇAO,HUMANISMO E DESENVOLVIMENTO CIENTIFICO E TECNOLOGICO,7.,2007,Salvador. Anais...Salvador:UFBA, 2007.Disponivel em:www.cinform.ufba.br>. Acesso em: 27 set. 2007. Acesso em: 27 set. 2010.
Resumo:
CUNHA, Jacqueline de Araújo. Biblioteca Digital de Teses e Dissertações: uma estratégia de preservação da memória científica. 2009. 141f. Dissertação (Mestrado)- Programa de Pós-Graduação em Ciência da Informação. Universidade Federal da Paraíba, João Pessoa, 2009.
Resumo:
A pesquisa aborda o uso das Tecnologias de Informação e Comunicação, que vem revolucionando as atividades e ocasionando muitas mudanças relacionadas ao acesso e uso de informações. O objetivo foi analisar o grau de utilização do conhecimento científico produzido pelos Programas de Pós-Graduação das Universidades Públicas Brasileiras, através da BDTD, pelos mestrandos dos referidos programas. Nos procedimentos metodológicos realizados, procurou-se inicialmente analisar o amplo espectro da população do corpus da pesquisa. Em razão da impossibilidade de trabalhar com os Programas de Pós-Graduação como um todo, optou-se por fazer um recorte, elegendo os cursos de Pós-Graduação em Ciência da Informação, vez que estes representam o principal segmento social de interesse da pesquisa. Foi utilizado o método de estudo de usuários, onde se optou por adotar o grupo, “estudos orientados aos usuários”, que identifica as necessidades e comportamento de acesso e uso da informação. Para coletar os dados, elaborou-se um questionário semi-estruturado com 25 questões, que versavam sobre o uso, dificuldades de acesso e recuperação da informação, bem como a satisfação na utilização dessa fonte informacional. Dentre os vários resultados obtidos, podemos destacar o fato de que a maioria dos mestrandos (71,8%) só teve contato com a BDTD somente no momento em que se encontrava cursando o mestrado e, somente 24,3%, tiveram contato durante a graduação. Estes resultados representam um problema, que pode afetar o bom desempenho do projeto BDTD, o qual consiste em disseminar e divulgar a produção científica dos Programas de Pós-Graduação das Universidades Públicas Brasileiras para a sua comunidade. Foi observado também, que os mestrandos oriundos do curso de Biblioteconomia tende a ter contato com a BDTD bem mais cedo do que mestrandos de outros cursos de graduação. A fim de minimizar o problema detectado, propõe-se uma divulgação mais eficaz na graduação através de dois procedimentos: Primeiro, o docente deve fazer uma divulgação mais eficaz da BDTD junto aos discentes de todos os cursos de graduação; segundo: deverá ser feita a divulgação na mídia eletrônica, através da inserção de ícones da BDTD, nos portais dos Departamentos dos Cursos de Graduação das Universidades Públicas Brasileiras. Acredita-se que com estes procedimentos seja possível aperfeiçoar o uso dessa fonte de informação científica.
Resumo:
A evolução da comunicação científica ao longo do tempo e o impacto causado pela A evolução da comunicação científica ao longo do tempo e o impacto causado pela A evolução da comunicação científica ao longo do tempo e o impacto causado pela se analisar as contribuições da Biblioteca Digital de Teses e Dissertações (BDTD)para a comunicação científica atual, destacando possibilidades emergentes e desafios a serem superados. Apresenta uma breve evolução da comunicação científica ao longo do tempo; discute os impactos causados pela Internet na comunicação, disponibilização e acessibilidade de informações técnico-científicas; e caracteriza BDTD destacando os desafios a serem superados. Dentre eles estão, a questão dos direitos autorais que ocasionam a baixa adesão dos autores ao projeto piloto do IBICT para disponibilizar teses e dissertações no meio eletrônico. Para este desafio, são apontadas sugestões.
Resumo:
As bibliotecas de teses e dissertações têm um papel fundamental para o desenvolvimento científico e cultural de um país. Nesse sentido, buscou-se, de modo geral, analisar o panorama brasileiro das bibliotecas digitais de teses e dissertações. Especificamente, objetivou-se caracterizar a sociedade da informação enquanto contexto das BDTD; caracterizar os vários tipos de bibliotecas surgidos a partir da inserção das novas tecnologias de informação e comunicação; identificar as diretrizes norteadoras da implantação de BDTD; e levantar as BDTD existentes no Brasil. Para tato, além de levantamento bibliográfico, realizou-se uma pesquisa nos sites de instituições de ensino superior brasileiras que já dispõe de bibliotecas digitais de teses e dissertações em funcionamento. A análise e interpretação destes dados nos permite considerar que no Brasil as BDTD encontram-se num estágio embrionário, sendo relevante pesquisar a histórica implantação e configuração desse novo modelo de biblioteca.
Resumo:
The vehicles are the main mobile sources of carbon monoxide (CO) and unburned hydrocarbons (HC) released into the atmosphere. In the last years the increment of the fleet of vehicles in the municipal district of Natal-RN it is contributing to the increase of the emissions of those pollutants. The study consisted of a statistical analysis of the emissions of CO and HC of a composed sample for 384 vehicles with mechanization Gasoline/CNG or Alcohol/Gasoline/CNG of the municipal district of Natal-RN. The tests were accomplished in vehicles submitted to Vehicular Safety's Inspection, in the facilities of INSPETRANS, Organism of Vehicular Inspection. An partial gases analyzer allowed to measure, for each vehicle, the levels of CO and HC in two conditions of rotation of the motor (900 and 2500 rpm). The statistical analysis accomplished through the STATISTICA software revealed a sensitive reduction in the efficiency of the converters catalytic after 6 years of use with emission average it is of 0,78% of CO and 156 (ppm) of HC, Which represents approximately 4 (four) times the amount of CO and the double of HC in comparison with the newest vehicles. The result of a Student s t-test, suggests strongly that the average of the emissions of HC (152 ppm), at 900 rpm, is 40% larger than at 2500 rpm, for the motor without load. This result reveals that the efficiency of the catalytic conversion is limited kinetically in low engine speeds. The Study also ends that when comparing the emissions of CO and HC considering the influence of the fuels, it was verified that although the emissions of CO starting from CNG are 62% smaller than arising from the gasoline, there are not significant differences among the emissions of HC originating from of CNG and of the gasoline. In synthesis, the results place the current criteria of vehicular inspection, for exhaust gases, in doubt, leading the creation of emission limits of pollutant more rigorous, because the efficiency of the converters catalytic is sensibly reduced starting from 6 years of use. It is also raised the possibility of modifications in the test conditions adopted by the current norms, specifically in the speed engine, have seen that in the condition without load the largest emission indexes were registered in slow march. That fact that allows to suggest the dismissal of the tests in high speed engine, reducing the time of inspection in half and generating economy of fuel
Resumo:
Photo-oxidation processes of toxic organic compounds have been widely studied. This work seeks the application of the photo-Fenton process for the degradation of hydrocarbons in water. The gasoline found in the refinery, without additives and alcohol, was used as the model pollutant. The effects of the concentration of the following substances have been properly evaluated: hydrogen peroxide (100-200 mM), iron ions (0.5-1 mM) and sodium chloride (200 2000 ppm). The experiments were accomplished in reactor with UV lamp and in a falling film solar reactor. The photo-oxidation process was monitored by measurements of the absorption spectra, total organic carbon (TOC) and chemical oxygen demand (COD). Experimental results demonstrated that the photo-Fenton process is feasible for the treatment of wastewaters containing aliphatic hydrocarbons, inclusive in the presence of salts. These conditions are similar to the water produced by the petroleum fields, generated in the extraction and production of petroleum. A neural network model of process correlated well the observed data for the photooxidation process of hydrocarbons
Resumo:
The chemical nature of the hidrocarbons found in gasoline directly affects the formation of oxidation complexes known as gums. Such complexes are slightly soluble in gasoline and their formation is delayed with the use of inhibitors, known as antioxidants. In this study, a synthetic compound (βnaphtol) and a natural subproduct (hydrogenated cardanol, derived from cashewnut shell liquid CNSL) have been used in order to generate novel antioxidant substances. These compounds were submitted to chemical reactions including alkylation, nitration and reduction, with the purpose of forming the following derivatives: 6(Nethyl,Nethylamino)βnaphtol (AO1); 6(Nethyl,Ndiethylamino)βnaphtol (AO2); aminoβnaphtol (AO3); 2(Nethyl,Nethylamino)pentadecylphenol (AOC1), 2(Nethyl,Ndiethylamino)pentadecylphenol (AOC2) and aminopentadecylphenol (AOC3). The derivatives were subjected to accelerated oxidative stability assays (Potential Gum and Induction Period) and to storage assays (Washed Gum and ASTM Color) during six months, with naphtha provided by the petroleum refinery RPBC (Refinaria Presidente Bernardes de Cubatão, in Brazil). The results for the derivatives were compared to those for commercial additives [DBPC (2,6ditbutyl4methylpcresol) and PDA (N,N disecbutylpphenylenediamine)], which were also added to the naphtha produced at RPBC at the moment of sampling. From all tested antioxidants, the novel antioxidant AOC1 (derived from hydrogenated cardanol) yielded a better global performance. During the period of time in which the naphtha was stored, an examination of this material was carried out in parallel, using the mass spectrometry technique. This study allowed to monitor the formation of a triolefinic compound, as well as the observation of subsequent formation and rupture of the olefinic constituents. As an eventual result from these experimental investigations, a reaction route leading to gum formation has been suggested
Resumo:
This work has the main purpose of conducting a survey of educational products present in dissertations and doctoral theses focused on the use of history in mathematics teaching and Didactics of mathematics with a French foundation produced in graduate programs in the strict sense of the Brazil between 1990 and 2010, the areas of Education, Mathematics Education, school of Natural Sciences and Mathematics and related areas, according to the research proposal of Mendes (2010). Our interest was to select the products that present concrete proposals for educational activities that can be used in the classroom of Basic Education and Training of Teachers of Mathematics. The research was implemented through a bibliographic study documents the Bank of dissertations and theses from CAPES, libraries and archives of some Postgraduate programs in the country who focus their studies on the subject object of this research, besides the Brazilian Digital Library Theses and Dissertations (BDBTD). From this survey we selected works that present educational products materialized in blocks of activities based on the use of teaching history of mathematics to the classroom as well as the sequence of activities based on the Teaching of Mathematics. In possession of material, produce a CD-ROM containing the selected activities, in order to help support the work of teachers regarding the use of these activities, as a supplementary material to textbooks in their math classes
Resumo:
This research aims to make a reflective analysis about the academic production originated in the stricto sensu post graduation programs in the country, produced in the period of 1990 to 2010, in the field of History of Mathematics, especifically on works about the History of Mathematics in Mathematics education and that present pedagogical proposals that make use of the History of Mathematics in order to teach Mathematics. Defending the thesis that the researches on mathematics education with goals turned to the use of didactic proposals related to the history of mathematic that take in consideration the coherency between epistemological aspects inherent to mathematics history and anthological elements materialized on the conceptions of mathematics and mathematics history and of apprenticeship (implicitly or explicitly exposed) may originate significant contribution to the field of history of mathematics on education. Among these, nine were Master’s Degree dissertations and five PHD’s theses. The reflective analysis was accomplished from two matrixes; one from theoretical nature and the other, ontologic nature, elaborated from the pretexts of Sanches Gamboa, about the epistemological analysis from academic production in the field of Mathematics Education and the following theoretical perspectives in the field of History of Mathematics Education, that are: linear evolutionary theory, structural construtivist operative, evolutionary discontinuous, historical and socialcultural investigation and the use of activities estimulating the usage of verbal and nonverbal expressions. These perspectives were based on the works of Miguel and Miorim, Mendes and Radford. As results, we have detected some established dissonances between the categories related to theoretical and ontologic levels and the pedagogical proposal presented in these researches. On the other hand, we have discovered works that are able to establish consonances between the theoretical and ontological elements and the presented pedagogical proposal. These works carry significative contributions to the field of History of Mathematics applied to Mathematics pedagogical practice, inclusively presenting significative theoretical elements to the production of knowledge recognized as scientific in the Mathematics field
Resumo:
The addition of hydrogen gas as an alternative fuel source has been widely used, as well reported in scientific literature. Today, several experiments are underway for the use of hydrogen generators (electrolysers) demand for motor vehicles. In all these products their ads manufacturers claim that this provides a reduction of fuel consumption, reduces the emission levels of toxic gas by the discharge and improves engine life. This research analyzes the physical structure of engine components using electrolysis on demand. To this end, a stationary system was fitted with a power generator of electricity, drum roller and adapted two electrolyzers: a dry cell and wet cell other. In steps observation were consumption analyzes in four work load ranges and observing the piston engine, which has been cut and analyzed by Optical Microscopy (OM), Scanning Electron Microscopy and Dispersive Energy (SEM-EDS), X – Ray Diffraction (XRD) and Confocal Microscopy, the stationary system in each step. The results showed a considerable reduction in fuel consumption and a high corrosion in the original factory piston constituted of aluminum-silicon alloy. As corrosion barrier was made a plasma nitriding in the piston head, which proved resistant to attack by hydrogen, although it has presented evidence also, of having been attacked. It is concluded that the automotive electrolysers can be a good choice in terms of consumption and reducing toxic gas emissions, but the material of the combustion chambers of vehicles must be prepared for this purpose.
Resumo:
This study aims to analyze the relationship between average price with the concentration in the markets (municipalities) in the state of Rio Grande do Norte, is using a little tool applied to the Brazilian market is the spatial econometric model. A data base contains all the stations of the major cities in the state of Rio Grande do Norte and includes 142 observations on stations was used. Theoretical models predict the relationship between the number of competitors in a market and the average price; these theoretical models include: the monopolistic competition of Perloff and Salop (1985), and the search-theoretic, of Carlson and McAfee (1983) and Varian (1980). The empirical results showed that a higher density within a geographic area is associated with a lower average price, thus converging with the monopolistic competition model and with the search-theoretic of Carlson and McAfee (1983). The parameters varied little with the inclusion / exclusion of control variables, showing the robustness of them.
Resumo:
This doctoral dissertationproposes the description, interpretation and analysis of the compositional structure of thesis and dissertation abstracts, with regard to the linguistic mechanisms that evidence text zones of different typological sequences, such as those of the text plan. Along these lines, the research problem was developed from the notion of compositional structure (sequences and text plans), as one of the levels or plans of text analysis, according to the theoretical framework proposed by Jean-Michel Adam (2011a). The main objective of this study was to recognize how the compositional structure, of thesis and dissertation abstracts, is achieved, with respect to text units and the global organization of this text category. The hypothesis posed in this research posits that specific informational text composition categories of abstracts are necessary to process the representation of the original text and the way in which it makes its meaning. Subsequently, this study is based on the theoretical and methodological framework of Text Linguistics (TL) and, above all, Textual Discourse Analysis (TDA), as we endeavor to understand the organizational structure of abstracts from both a linguistic and textual perspective. This structure involves the text plan of abstracts, with respect to their communicative purpose, i.e, the sharing of scientific information in its standard textual form. Thus, the development of this study, from a theoretical and methodological perspective, is based on the theoretical and descriptive premises from TDA (ADAM, 2011a, 2012; PASSEGGI et al., 2010), and also from TL (BEAUGRANDE; DRESSLER, (2012 [1981]); COSERIU; LAMAS (2010); MARCUSCHI, 2009 [1983]; FÁVERO; KOCH, 1994;KOCH, 2006; BENTES, 2004; BENTES; LEITE, 2010), within the field of text studies. The methodology of this study relies on empirical, documental research, which is qualitative, and adopts a descriptive and interpretive approach. From the empirical perspective, our objective is to understand the problems pertaining to the textual composition of abstracts, aiming to elucidate them in light of the theoretical and methodological framework previously mentioned. The corpus of the analysis is comprised of seven abstracts designated for systematic data collection. These texts, written between 2004 and 2011,were selected from Master’s theses and Doctoral dissertations in their electronic version, from the graduate program at the Federal University of Rio Grande do Norte. A thorough review of the literature reveals a clear fluctuation in the terminology of the concept, ‘abstract’. The results of the analysis revealed that the abstracts, which comprise the corpus of analysis in this study, in general, present typological heterogeneity, while the text plan remains fixed. Finally, the new knowledge gained in this research contributes both to the understanding of the compositional structure of abstracts as well as their production.
Resumo:
This study is an analysis, on a trial basis, the fuel consumption of a Flex vehicle, operating with different mixtures of gasoline and ethanol in urban traffic, allowing more consistent results with the reality of the driver. Considering that most owners unaware of the possibility of mixing the fuel at the time of supply, thus enabling the choice of the most economically viable mixing gasoline / ethanol, resulting in lower costs and possibly a decrease in pollutant emission rates. Currently, there is a myth created by the people that supply ethanol only becomes viable if the value of not more than 70% of regular gasoline. However vehicles with this technology make it possible to operate with any percentage of mixture in the fuel tank, but today many of the owners of these vehicles do not use this feature effectively, because they ignore the possibility of mixing or the reason there is a deeper study regarding the optimal percentage of the mixture to provide a higher yield with a lower cost than proposed by the manufacturers.