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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Avalia??o de concretos autoadens?veis com baixos consumos de cimento incorporando metacaulim, pozolana da casca do arroz, f?ler calc?rio e adi??o de cal hidratada / Evaluation of self-compacting concretes with low content of cement incorporating metakaolin, pozzolan of rice husk, limestone filler, and addition of hydrated lime

Fonseca, Thiago Vieira 15 December 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-14T22:33:05Z No. of bitstreams: 1 ThiagoVieiraFonseca_DISSERT.pdf: 2958142 bytes, checksum: c66f334f99f3044869ebf39752984389 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-16T19:54:31Z (GMT) No. of bitstreams: 1 ThiagoVieiraFonseca_DISSERT.pdf: 2958142 bytes, checksum: c66f334f99f3044869ebf39752984389 (MD5) / Made available in DSpace on 2017-03-16T19:54:31Z (GMT). No. of bitstreams: 1 ThiagoVieiraFonseca_DISSERT.pdf: 2958142 bytes, checksum: c66f334f99f3044869ebf39752984389 (MD5) Previous issue date: 2016-12-15 / O concreto autoadens?vel (CAA) possui elevado teor de materiais finos e vem sendo bastante utilizado devido as suas caracter?sticas de alta fluidez e coes?o. Os finos provindos de res?duos ou subprodutos industriais podem vir a ser usados em prol da sustentabilidade, minimizando consideravelmente o consumo de cimento associado ? possibilidade de manter, ou melhorar, as propriedades mec?nicas ou de durabilidade. Desta forma, o presente trabalho investigou a viabilidade do desenvolvimento de CAA?s confeccionados com elevados teores de adi??es minerais e cal hidratada. Para isso, o cimento foi substitu?do por adi??es minerais (pozolana da casca do arroz, metacaulim e f?ler calc?rio) no teor de 60%, com base no tra?o de refer?ncia com consumo de 451,1 kg/m? de cimento, originando novos tra?os com consumos de cimento entre 167,7 kg/m? e 173,3 kg/m?. A cal hidratada foi incorporada como adi??o em tr?s tra?os no teor de 5% sobre a massa total dos materiais finos. Os CAA?s foram caracterizados no estado fresco pelos ensaios de espalhamento, T500, anel-J, funil-V e caixa-L. Para avalia??o do desempenho mec?nico dos CAA?s foram realizados ensaios de resist?ncia ? compress?o, velocidade do pulso ultrass?nico e m?dulo de elasticidade est?tico, bem como propriedades de transporte relacionadas ? durabilidade: absor??o por capilaridade, difus?o de ?ons cloreto, resistividade el?trica e carbonata??o. Os CAA?s com adi??es minerais apresentaram desempenho mec?nico satisfat?rio, embora inferiores ao do tra?o de refer?ncia. As resist?ncias ? compress?o aos 28 dias dos concretos com adi??es minerais apresentaram redu??o de 15 a 60% em rela??o ao tra?o de refer?ncia, mas todos os resultados foram compat?veis com concretos estruturais de acordo com os requisitos da NBR 6118 (ABNT, 2014). Com rela??o a durabilidade, os concretos com adi??es minerais apresentaram redu??o do coeficiente de difus?o de ?ons cloreto que variaram entre 25,4% e 74,8%. As resistividades el?tricas do concreto de refer?ncia foram bastante inferiores ?s dos concretos com adi??es minerais, mas todas as composi??es estudadas foram classificadas como prov?vel taxa de corros?o desprez?vel. As resistividades el?tricas sofreram grande redu??o quando analisadas em amostras carbonatadas. J? a an?lise da carbonata??o acelerada mostrou que a substitui??o do cimento por adi??es minerais em elevados teores torna os CAA?s bastante suscet?veis a carbonata??o. Quanto a adi??o de cal hidratada, n?o foi verificada influ?ncia positiva no desempenho mec?nico dos CAA?s estudados, mas observou-se que sua utiliza??o proporcionou redu??o da profundidade de carbonata??o nos CAA?s devido a reposi??o da reserva alcalina. / Self-compacting concrete (SCC) has a high content of fine materials and has been widely used due to its characteristics of high fluidity and cohesion. Fines from industrial waste or by-products may be used for the sake of sustainability, considerably reducing the consumption of cement associated with the possibility of maintaining or improving mechanical or durability properties. In this way, the present work investigated the feasibility of the development of SCC's made with high levels of mineral additions and hydrated lime. For this purpose, the cement was replaced by mineral additives (rice husk pozzolan, metakaolin and limestone filer) in the 60% content, based on the reference mixture with consumption of 451.1 kg / m? of cement, giving rise to new mixtures with consumption of cement between 167.7 kg / m? and 173.3 kg / m?. The hydrated lime was incorporated as an addition in three mixtures in the content of 5% on the total mass of the fine materials. The SCC's were characterized in the fresh state by the slump flow test, T500, J-ring, V-funnel and L-box. To evaluate the mechanical performance of the SCC's, tests of compressive strength, ultrasonic pulse velocity and static modulus of elasticity, as well as transport properties related to durability were performed: capillary absorption, chloride ion diffusion, electrical resistivity and carbonation. The SCC's with mineral additions presented satisfactory mechanical performance, although lower than the reference mixture. The compressive strength at 28 days of the concretes with mineral additions showed a reduction of 15 to 60% in relation to the reference mixture, but all the results were compatible with structural concretes according to the requirements of NBR 6118 (ABNT, 2014). Regarding the durability, the concrete with mineral additions presented reduction of the diffusion coefficient of chloride ions that varied between 25.4% and 74.8%. The electrical resistivities of the reference concrete were much lower than those of the concretes with mineral additions, but all the studied compositions were classified as probable negligible corrosion rates. The electrical resistivities suffered great reduction when analyzed in carbonated samples. The analysis of the accelerated carbonation showed that the substitution of cement by mineral additions at high levels makes the SCC very susceptible to carbonation. As for the addition of hydrated lime, there was no positive influence on the mechanical performance of the SCC's studied, but it was observed that its use provided a reduction of the carbonation depth in the SCC's due to the alkaline reserve.
2

Diagn?stico de contamina??o por derivado de petr?leo no solo e na ?gua subterr?nea em um terminal aquavi?rio: estudo de caso na cidade de Natal/RN

Lucas, Ana Carolina Mar?al Pires Ferreira 31 March 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-07-03T12:22:22Z No. of bitstreams: 1 AnaCarolinaMarcalPiresFerreiraLucas_DISSERT.pdf: 2241069 bytes, checksum: cc1d053944af95b14551bddf9de6e962 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-07-05T15:51:20Z (GMT) No. of bitstreams: 1 AnaCarolinaMarcalPiresFerreiraLucas_DISSERT.pdf: 2241069 bytes, checksum: cc1d053944af95b14551bddf9de6e962 (MD5) / Made available in DSpace on 2017-07-05T15:51:20Z (GMT). No. of bitstreams: 1 AnaCarolinaMarcalPiresFerreiraLucas_DISSERT.pdf: 2241069 bytes, checksum: cc1d053944af95b14551bddf9de6e962 (MD5) Previous issue date: 2017-03-31 / As Unidades de Terminais Aquavi?rios tem como fun??o principal receber, armazenar e distribuir petr?leo, derivados e combust?veis renov?veis l?quidos, garantindo o abastecimento dos mercados nacional e internacional. A grande movimenta??o log?stica gerada pela explora??o, beneficiamento, armazenagem, transporte e comercializa??o do petr?leo e seus derivados vem gerando preocupa??es relacionadas ? sua potencialidade de contamina??o do ambiente. Por causa dos in?meros acidentes com derramamento de combust?veis, os quais ocasionam contamina??es de solos e ?guas por hidrocarbonetos derivados de petr?leo, torna as pesquisas neste contexto um desafio para os profissionais que atuam na ?rea, em fun??o da complexidade de intera??es que ocorrem no solo e na ?gua. O Terminal, objeto de estudo, est? localizado na cidade de Natal-RN e ocupa uma ?rea de 110.000 m2. O estudo visa avaliar a contamina??o do solo e ?gua subterr?nea por derivados de petr?leo na bacia do tanque 1430-04, caracterizando a presen?a de subst?ncias com potencial de contamina??o atrav?s de dados obtidos pela coleta de amostras do solo e ?gua distribu?das para an?lise dos par?metros TPH fracionado, BTEX, VOC, SVOC e Metais. Como tamb?m, a an?lise dos par?metros f?sicos do solo (granulometria, porosidade total e efetiva, densidade de part?culas e total do solo, umidade natural) e fra??o de carbono org?nico. As an?lises qu?micas das amostras de solo n?o apresentaram concentra??es dos par?metros analisados (TPH, BTEX, VOC, SVOC e Metais). Nas amostras de ?gua subterr?neas foram detectadas concentra??es de benzeno, al?m de xilenos e TPH. Para os metais, foram detectados concentra??es de chumbo, al?m do ferro. J? para os metais dissolvidos apenas o chumbo apresentou concentra??es acima dos valores de investiga??o. Todos os resultados das an?lises qu?micas foram comparados com os valores da Resolu??o 420 do CONAMA de 2009. / The Aquavi?rios Terminal Unit's main function is to receive, store and distribute oil, oil products and liquid renewable fuels, ensuring the supply of domestic and international markets. The great logistic movement generated by the exploration, processing, storage, transportation and commercialization of oil and its derivatives has generated worries related to its potential contamination of the environment. Because of the numerous accidents with fuel spills, which cause contamination of soils and waters by oil-derived hydrocarbons, research in this context makes it a challenge for professionals working in the area, due to the complexity of interactions occurring in the soil and in the water. The Terminal, object of study, is located in the city of Natal-RN and occupies an area of 110,000 m2. The aim of this study is to evaluate soil and groundwater contamination by petroleum by-products in the 1430-04 basin, characterizing the presence of substances with potential contamination in soil and groundwater through the collection of soil and water samples for the analysis of TPH fractional parameters, BTEX, VOC, SVOC and metals. As well as the analysis of soil physical parameters (particle size, total and effective porosity, particle density and total soil, natural moisture) and organic carbon fraction. The chemical analyzes of soil samples did not present concentrations of the analyzed parameters (TPH, BTEX, VOC, SVOC and metals). Concentrations of benzene were detected in the groundwater samples, in addition to xylenes and TPH. For metals, concentrations of lead were detected in addition to iron. For dissolved metals, only lead had concentrations above the values investigated. All results of the chemical analyzes were compared with the values of CONAMA Resolution 420/2009.
3

Desenvolvimento de m?todo para indica??o de servi?os suplementares telef?nicos baseado em consultas em linguagem natural / Development of a method for telephonic supplementary services indication based on consults made in natural language

Anjos, Renata Martins dos 24 September 2007 (has links)
Made available in DSpace on 2016-04-04T18:31:20Z (GMT). No. of bitstreams: 1 Renata Martins dos Anjos.pdf: 816323 bytes, checksum: f01807d9e2ff56f55d3005a95cab513a (MD5) Previous issue date: 2007-09-24 / This dissertation defines a method to support the use of an interface in natural language mediated by the Web for the indication of supplementary services to the customers of telecommunications carriers. The method is based on the generation of indicative patterns of the presence of suplementary services in texts starting from the central ideas that capture the main meaning of the suplementary services and from hypothetical users questions, named generating questions in this dissertation. The set of indicative patterns associated to a given suplementary service is compared to a given user question that describes a situation to be resolved through the use of a suplementary service. When the matching between the question and an indicative pattern associated to the suplementay service occurs, this service is indicated to the user. Only the suplementary services pertaining to a predefined scope determined by the carrier will be indicated. The objective of the considered method encloses neither the diagnostic of problems related to the services nor the treatment of questions that require the description of a service as a reply. This dissertation also presents an experiment where potential telecommunication carriers users write their questions in natural language, supposing the use of an hipothetical Web interface to request indications of suplementary services in order to address a specific demand. The results of this study are analyzed taking into account the problems found as well as the rate of success obtained by the application of the method. The method specially aims to offer a new option to attend a fixed or mobile carrier s customers, making possible the use of its human resources for nobler interactions where the intervention of a human being is essential. / Este trabalho define um m?todo para suportar a utiliza??o de uma interface em linguagem natural via Web para a indica??o de servi?os suplementares a usu?rios de companhias operadoras de servi?os de telecomunica??es. O m?todo baseia-se na gera??o de padr?es indicativos da presen?a de servi?os suplementares em textos a partir das id?ias centrais que capturam o significado principal dos servi?os suplementares e de quest?es hipot?ticas de usu?rios, denominadas nesta disserta??o de quest?es geradoras. O conjunto de padr?es indicativos associado a um dado servi?o suplementar ? comparado com uma dada quest?o de usu?rio, que descreve uma situa??o a ser resolvida pela utiliza??o de um servi?o suplementar. Quando ocorre matching entre a quest?o e um padr?o indicativo associado ao servi?o suplementar, este ? indicado ao usu?rio. Somente ser?o indicados servi?os suplementares pertencentes a um escopo pr?-definido de servi?os e determinado pela operadora. O escopo do m?todo proposto n?o abrange o tratamento de diagn?sticos de problemas relativos a servi?os nem o tratamento de quest?es que requeiram a descri??o de um servi?o como resposta. Esta disserta??o apresenta ainda um experimento onde usu?rios potenciais de uma companhia operadora de servi?os de telecomunica??espodem postar suas quest?es em linguagem natural, supondo a utiliza??o de uma interface hipot?tica via Web para solicitar indica??es de servi?os suplementares que atendam a uma demanda espec?fica. Os resultados deste estudo s?o analisados do ponto de vista dos problemas encontrados, bem como da taxa de sucesso obtida pela aplica??o do m?todo. O m?todo visa, em especial, oferecer uma nova op??o de atendimento aos usu?rios de uma operadora de telefonia fixa ou m?vel, possibilitando assim o direcionamento dos seus recursos humanos para atendimentos onde a interven??o de um ser humano se fa?a imprescindivelmente necess?ria.
4

Avalia??o de HPA e BTEX no solo e ?gua subterr?nea, em postos de revenda de combust?veis: estudo de caso na cidade de Natal -RN

Anjos, Raoni Batista dos 14 December 2012 (has links)
Made available in DSpace on 2014-12-17T14:08:52Z (GMT). No. of bitstreams: 1 RaoniBA_DISSERT.pdf: 2283831 bytes, checksum: 9e3bfc1213fc5b5ac439fb175ddc5631 (MD5) Previous issue date: 2012-12-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The retail fuel stations are partially or potentially polluters and generators of environmental accidents, potentially causing contamination of underground and surface water bodies, soil and air. Leaks in fuel retail stations? underground storage systems are often detected in Brazil and around the world. Monoaromatic hydrocarbons, BTEX (benzene, toluene, ethylbenzene and xylenes) and polycyclic aromatic hydrocarbons (PAHs) are an indication of the presence of contamination due to its high toxicity. This paper presents a case study of contamination in a Fuel Retail Station by petroleum derivative products in the city of Natal. For identification and quantification of the hydrocarbons, EPA analytical methods were used. The values of benzene quantified by EPA method 8021b CG-PID/FID, ranged from 1.164 to 4.503 mg.Kg-1 in soil samples, and from 12.10 to 27,639 μg.L-1 in underground water samples. Among the PAHs, naphthalene and anthracene showed the most significant results in soil samples, 0.420 to 15.46 mg.Kg-1 and 0.110 to 0,970 mg.Kg-1, respectively. In underground water samples, the results for Naphthalene varied between 0.759 and 614.7 μg.L-1. PAHs were quantified by EPA Method 8270 for GCMS. All of the results for the chemical analysis were compared with the values for the CONAMA 420/2009 resolution. The results for benzene (27,639 μg.L-1) showed levels highly above the recommended by the CONAMA 420 resolution, wherein the maximum permissible for underground water is 5 μg.L-1. This is a worrying factor, since underground water makes up 70% of the city of Natal?s water supply / The retail fuel stations are partially or potentially polluters and generators of environmental accidents, potentially causing contamination of underground and surface water bodies, soil and air. Leaks in fuel retail stations? underground storage systems are often detected in Brazil and around the world. Monoaromatic hydrocarbons, BTEX (benzene, toluene, ethylbenzene and xylenes) and polycyclic aromatic hydrocarbons (PAHs) are an indication of the presence of contamination due to its high toxicity. This paper presents a case study of contamination in a Fuel Retail Station by petroleum derivative products in the city of Natal. For identification and quantification of the hydrocarbons, EPA analytical methods were used. The values of benzene quantified by EPA method 8021b CG-PID/FID, ranged from 1.164 to 4.503 mg.Kg-1 in soil samples, and from 12.10 to 27,639 μg.L-1 in underground water samples. Among the PAHs, naphthalene and anthracene showed the most significant results in soil samples, 0.420 to 15.46 mg.Kg-1 and 0.110 to 0,970 mg.Kg-1, respectively. In underground water samples, the results for Naphthalene varied between 0.759 and 614.7 μg.L-1. PAHs were quantified by EPA Method 8270 for GCMS. All of the results for the chemical analysis were compared with the values for the CONAMA 420/2009 resolution. The results for benzene (27,639 μg.L-1) showed levels highly above the recommended by the CONAMA 420 resolution, wherein the maximum permissible for underground water is 5 μg.L-1. This is a worrying factor, since underground water makes up 70% of the city of Natal?s water supply
5

A formação das capacidades dinâmicas por meio da gestão de indicativos de conhecimento

Pereira, Alana Deusilan Sester 28 May 2018 (has links)
Submitted by Alana Deusilan Sester Pereira (aladesp@gmail.com) on 2018-06-27T01:20:41Z No. of bitstreams: 1 ALANA PEREIRA - TESE FINAL .pdf: 2432521 bytes, checksum: c79a7baeaaff595830f99c5d9a8b4fc1 (MD5) / Approved for entry into archive by Maria Tereza Fernandes Conselmo (maria.conselmo@fgv.br) on 2018-06-29T23:23:32Z (GMT) No. of bitstreams: 1 ALANA PEREIRA - TESE FINAL .pdf: 2432521 bytes, checksum: c79a7baeaaff595830f99c5d9a8b4fc1 (MD5) / Approved for entry into archive by Isabele Garcia (isabele.garcia@fgv.br) on 2018-07-02T12:39:45Z (GMT) No. of bitstreams: 1 ALANA PEREIRA - TESE FINAL .pdf: 2432521 bytes, checksum: c79a7baeaaff595830f99c5d9a8b4fc1 (MD5) / Made available in DSpace on 2018-07-02T12:39:45Z (GMT). No. of bitstreams: 1 ALANA PEREIRA - TESE FINAL .pdf: 2432521 bytes, checksum: c79a7baeaaff595830f99c5d9a8b4fc1 (MD5) Previous issue date: 2018-05-28 / Este trabalho tem como objetivo geral propor um framework teórico-analítico que suscite reflexões sobre como as organizações podem desenvolver capacidades dinâmicas por meio da gestão de indicativos de conhecimentos. Assim, este estudo inova ao verificar empiricamente como os conhecimentos identificados no monitoramento do ambiente externo constituem em indicativos e, com isso, possibilitam criar capacidades que se adaptem às tendências e exigências do meio em que estão inseridas. Nesse contexto, tendo como marco teórico a bibliografia sobre capacidades dinâmicas, gestão do conhecimento e aprendizagem organizacional, identificou-se uma lacuna nos trabalhos publicados, visto que eles não abordam processos relativos ao conhecimento, como, por exemplo, o de seleção, priorização e monitoramento. Desse modo, a estratégia de investigação apoiou-se em uma abordagem qualitativa com o emprego do método de estudo de casos múltiplos. A coleta de dados foi realizada in loco e fez uso de múltiplas fontes de evidências com auxílio das seguintes técnicas de coleta: pesquisa bibliográfica, entrevistas semiestruturadas, análise documental e observação direta. O setor escolhido foi o de Tecnologia da Informação. No total, foram realizados cinco estudos de casos e 23 entrevistas, resultando em um material equivalente a 1.159 minutos e 781 páginas de transcrição. Para o estudo dos dados, utilizou-se como estratégia a análise em profundidade de cada caso, com o auxílio da técnica de análise de conteúdo. Os resultados do estudo indicam os principais fatores internos organizacionais que contribuem para o desenvolvimento das capacidades dinâmicas; as práticas de monitoramento dos fatores externos; os conhecimentos identificados que suscitam em indicativos; as principais práticas de gestão do conhecimento empregadas pelas empresas estudadas; as decisões e resultados obtidos por meio da utilização dos indicativos de conhecimento; a relação desses indicativos com as decisões deliberadas; e, por fim, a proposta de elaboração do framework a partir de oito proposições inéditas acerca do desenvolvimento de capacidades dinâmicas por meio de indicativos de conhecimentos. Nesse sentido, a tese contribui explicitando indícios de que as práticas identificadas oferecem importante suporte para a efetividade dos indicativos em termos da identificação da sua relevância, acompanhamento e aprendizagem, conduzindo as decisões com efeito aos bons resultados obtidos nas empresas pesquisadas. Espera-se, portanto, que a estrutura analítica e as proposições apresentadas instiguem novas investigações para desenvolvimento das teorias de gestão do conhecimento e de capacidades dinâmicas. / The general purpose of this work is to propose a theoretical-analytical framework that arouses reflections on how organizations can develop dynamic capacities through the management of indicative knowledge. Thus, this study innovates by verifying empirically how the knowledge identified in the monitoring of the external environment constitute indicative and, thereby, enable the creation of capacities that adapt to the tendencies and demands of the environment in which they are inserted. In such a context, having as a theoretical milestone the bibliography on dynamic capacities, knowledge management and organizational learning, a gap has been identified in the published works, since they do not deal with processes related to knowledge, such as selection, prioritization and monitoring through indicative. Therefore, the research strategy was based on a qualitative approach using the multicase study method. Data collection was performed on-site and made use of multiple sources of evidence with the aid of the following collection techniques: bibliographic research, semi-structured interviews, documentary analysis and direct observation. The chosen sector was Information Technology. In total, 5 case studies and 23 interviews were conducted, resulting in material equivalent to 1,159 minutes and 781 pages of transcription. In order to study the data, the in-depth analysis of each case was used as strategy and the content analysis technique was used. The results of the study indicate the main internal organizational factors that contribute to the development of dynamic capacities; the practices of monitoring external factors; the identified knowledge that elicits indicatives the main knowledge management practices employed by the companies studied; the decisions and results obtained through the use of indicatives of knowledge; the relationship of these indicatives with the deliberate decisions; and, finally, the framework’s proposal of elaboration from eight unpublished propositions about the development of dynamic capacities through knowledge indicatives. For that matter, the thesis makes explicit evidence that the identified practices offer important support for the effectiveness of the indicatives in terms of identifying their relevance, follow-up and apprenticeship, leading decisions to effect the good results achieved by the companies surveyed. Therefore, it is expected that the analytical structure and the propositions presented instigate new investigations for the development of theories of knowledge management and dynamic capacities.

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