169 resultados para Vazios irbanos
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The master thesis for the achievement of the academic status master of science in international management (MPGI) will aim to solve the research question of how institutional voids affect the entry decision-making process of foreign venture capital firms coming to Brazil. This is a timely matter since in the past years there has been a sudden eruption of foreign VC involvement in Brazil. Based on the actionable framework by Khanna and Palpeu (2010) we conducted quantitative as well as qualitative research with two sets of interview partners in a two-phase analysis. We interviewed experts from VC firms, foreign VC firms based in Brazil and perspective VC firms that are looking to come to Brazil. We started with the former, derived lessons learned and analyzed how they affect the latter in reaching a decision. As we expected we found that depending on the industry that ventures are in, institutional voids can either pose an opportunity or a threat and hence attract or push away potential VC firms entering Brazil. Opportunities exist especially when exploiting institutional voids, for example through ventures in the marketplace efficiency. Threats are posed by investments in for instance hard infrastructure, where the economic, political and judicial systems as well as corruption and bureaucracy play demanding roles.
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Nesta dissertação pretende-se estudar a influência da não saturação de solos compactados no comportamento mecânico das camadas de aterro, nomeadamente de infraestruturas de transportes. Os aterros são normalmente construídos através de camadas de solo compactado em condições não saturadas, cujo comportamento mecânico varia ao longo da sua extensão apesar de serem aplicadas as mesmas forças de compactação. Para tal podem ser identificadas várias explicações de forma a justificar o comportamento mecânico da camada como o tipo de solo, as alterações das condições de estado, ou seja, do índice de vazios e do teor em água. Estas variações ao longo das camadas dão origem a diferentes forças de sucção entre as partículas do solo condicionando, originando assim variações no comportamento mecânico das camadas de aterro. O estudo conduzido no presente trabalho tem por base os resultados de ensaios in-situ realizados num aterro experimental, onde foram executadas camadas de aterro com diferentes teores em água. A partir da caracterização do comportamento mecânico e das condições de estado avalia-se a influência da não saturação das camadas. Este estudo é complementado com uma campanha de ensaios de laboratório onde se avalia a influência das condições de estado, nomeadamente o teor em água e o índice de vazios, nas forças de sucção, que estão diretamente relacionadas com o comportamento mecânico do solo compactado.
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This work has as its theme the social function of terrenos de marinha. Theresearch universe is the terrenos de marinha of Natal coastline, focusing on thefulfillment of its social function. Prescribed by law since the colonial period with thepurpose of protecting the coast and free movement of people and goods, theywere swathes of land not available to private use by individuals. With the transitionfrom the allotments system to the purchase and sale, regard to land access,crystallized with the creation of the Land Law in the nineteenth century, the land isheld as merchandise and terrenos de marinha, following this logic, also acquireexchange value and become capable of enjoyment by private individuals, with thecondition of tax payments to the state. This is seen until the twentieth century,when in 1988, primarily because of the Federal Constitution promulgation, begins anew cycle when is possible to use on terrenos de marinha the principle of thesocial function of property. From this perspective this study aims to identify thesocial function of terrenos de marinha in Natal, focusing on the public destinationand the use value of the city coastline. To this end, it was made a data collection inthe on-line information system of the Federal Heritage Department of Rio Grandedo Norte (SPU / RN) and in the terrenos de marinha areas, in order to find out ifthey had public or private use, or if they were empty lots, as well as if thepopulation access to the shore exist. Interviews with managers of the SPU weremade. The empirical study showed that the social function of terrenos de marinhain the city of Natal still didn´t happen, considering the constant existence of vacantlots in their areas, the lack of access in significant portions of the coastline and thereduced areas directed to common use along the coastline, minimizing its potentialof enjoyment by the population. It concludes by pointing to the existence of a newtransition phase on the terrenos de marinha, in witch, gradually, come up lawprovisions in the legal system and public policies to expand the purely taxcollection function attributed to this land for two centuries. In this direction, thesocial function of terrenos de marinha is embodied in concomitant adjustment ofthe tax collection function and the rescue of coastline use value, national heritageand a place for sociability and social relations development
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The cobalt-chromium alloy is extensively used in the Odontology for the confection of metallic scaffolding in partial removable denture. During the last few years, it has been reported an increasing number of premature imperfections, with a few months of prosthesis use. The manufacture of these components is made in prosthetic laboratories and normally involves recasting, using parts of casting alloy and parts of virgin alloy. Therefore, the objective of the present study was to analyze the mechanical properties of a commercial cobalt-chromium alloy of odontological use after successive recasting, searching information to guide the dental prosthesis laboratories in the correct manipulation of the cobalt-chromium alloy in the process of casting and the possible limits of recasting in the mechanical properties of this material. Seven sample groups were confectioned, each one containing five test bodies, divided in the following way: G1: casting only with virgin alloy; G2: casting with 50% of the alloy of the G1 + 50% of virgin alloy; G3: casting with 50% of the alloy of the G2 + 50% of virgin alloy; G4: casting with 50% of the alloy of the G3 + 50% of virgin alloy; G5: 50% of alloy of the G4 + 50% of virgin alloy; G6: 50% of alloy of the G5 + 50% of virgin alloy and finally the G7, only with recasting alloy. The modifications in the mechanical behavior of the alloy were evaluated. Moreover, it was carried the micro structural characterization of the material by optic and electronic scanning microscopy, and X ray diffraction.and fluorescence looking into the correlatation of the mechanical alterations with structural modifications of the material caused by successive recasting process. Generally the results showed alterations in the fracture energy of the alloy after successive recasting, resulting mainly of the increasing presence of pores and large voids, characteristic of the casting material. Thus, the interpretation of the results showed that the material did not reveal significant differences with respect to the tensile strength or elastic limit, as a function of successive recasting. The elastic modulus increased from the third recasting cycle on, indicating that the material can be recast only twice. The fracture energy of the material decreased, as the number of recasting cycles increased. With respect to the microhardness, the statistical analyses showedno significant differences. Electronic scanning microscopy revealed the presence of imperfections and defects, resulting of the recasting process. X ray diffraction and fluorescence did not show alterations in the composition of the alloy or the formation of crystalline phases between the analyzed groups. The optical micrographs showed an increasing number of voids and porosity as the material was recast. Therefore, the general conclusion of this study is that the successive recasting of of Co-Cr alloys affects the mechanical properties of the material, consequently leading to the failure of the prosthetic work. Based on the results, the best recommendadition is that the use of the material should be limited to two recasting cycles
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The reef area of Pirangi beach has been experiencing antropogenic actions, mainly due to tourism activity. In order to evaluate these effects, surveys on seaweeds were conducted at nine stations located over the fringing reef. Benthic community (seaweeds/corals) were identified using the photoquadrat method, with 50 meters random transects located paralleled to the coast. The general categories evaluated in each transect were: rock, sand, seaweeds, corals and mollusks. Data achieved were processed at Coral Point Count with Excel Extensions software. A total of 30 seaweed species, 5 coral species and 1 mollusk species were identified. There was a high dominance of short algae at stations with high tourism pressure, whereas frondose algae usually occurred at places without human interference. Seaweeds with the highest percent cover were composed by Sargassum vulgare (59%), Caulerpa racemosa (47%) and Dictyopteris delicatula (33%). Cluster analyses considering benthic organisms revealed five benthic features: (1) submersed area characterized by a diversified marine flora; (2) area with dominance of Caulerpa racemosa and presence of Millepora alcicornis; (3) area with high cover of Sargassum vulgare; (4) trampling area characterized by bare rocks, short algae and Zoanthus sociatus and (5) area with high coverage of Palythoa caribaeroum. Obtained data suggest that the studied area has been damaged by tourism activities. Furthermore, observed differences in algal communities may be a good indicator of ecosystem health of Pirangi reefs
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Soil improved with the addition of cement have been utilized as an alternative to the construction of various types of geotechnical works, almost always present economic and environmental advantages. This paper presents a study on the usage of cement in the improvement of mechanical properties of sandy soils, characteristic of the region of Natal, collected from its dunes. This research was made in order to analyze the influence of cement content, voids, and also including water immersion and confining pressure. Samples molded from cement-soil mixtures were tested for unconfined compression tests and triaxial tests. The samples had the percentage of cement mixed in 2.5%, 5% and 10% by weight. The cement agent used was the Portland Cement of High Early strength(CPV-ARI), which promoted agility to the experimental procedure for presenting a rapid gain in strenght. The void ratio used ranged from 0.7 (more compact), 0,9 and 1,1(softer). The soil under study can be considered as pure sand. In general, it can be stated that the larger the amount of cement added to the sand studied is, the greater ultimate strength will be. Likewise, as more compact the soil is, the less void ratio and more resistant it will be present. The confining pressure tends to increase the resistance of the specimens. The cementing adopted grades showed that the use of different criteria for failure did not significantly alter the stress-strain parameters for the sand studied. The angle of friction values were found within the typical range of medium and compact sands. Cementing acted in the sand providing an intercepted cohesion which increased enhancing the potential cementation. In triaxial compression tests, the sand with void ratio is equal to 0.7 and showed the expected behavior for a compact sand while the stress-strain behavior of the same sand with the void ratio of 0.9 tended to be expected for the soft sand as well
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Concrete is the second most consumed product in the world and the incorporation of the Sugar Bagasse Ash (SBA) into this material can provide solutions for the utilization of by-products from other industries, thus reducing the environmental impact. The general aim of this dissertation focuses on analyzing the mechanical behavior of concrete with addition of SBA from three different species of sugar cane, through tests of consistency, compressive strength, porosity, absorption, voids and Scanning Electron Microscopy (SEM). Were prepared 13 specimens for each specific pattern and level of incorporation of SBA (10%, 20% and 30%) of the three varieties collected, totaling 130 samples of concrete. The trait was employed 1:2:3 (cement: sand: aggregates) in relation to the cement mass with a water / cement ratio of 0.532 and 1% additive Tec 400 Mult also based on the weight of cement. According to the results obtained in this study, it was concluded that the variety of cane sugar, used in the production of the CBC, influenced the mechanical behavior of the resulting concrete. All concrete with addition of SBA, reported a reduction of at least 10% in the properties related to permeability and an increase in the compressive strength of at least 16% compared to standard concrete at 28 days
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From the 70`s, with the publication of the Manifesto for Environment UN Conference, held in Stockholm, in Sweden (1972), defend and improve the environment became part of our daily lives. Thus, several studies have emerged in several segments in order to reuse the waste. Some examples of waste incorporated in portland cement concrete are: rice husk ash, bagasse ash of cane sugar, powder-stone, microsilica, tire rubber, among others. This research used the residue of the mining industry Scheelite, to evaluate the incorporation of the residue composition of Portland cement concrete, replacing the natural sand. The percentage of residue were incorporated from 0% to 100%, with a variation of 10%, 11 being produced concrete mix in the ratio 1:2:3:0.60, by mass. We evaluated the following characteristics of concrete: slump test, compressive strength, tensile strength by diametral compression, water absorption, porosity and density, based on the ABNT, through tests performed in the Laboratory of Civil Construction, UFRN. The trace with the addition of 60% scheelite residue was obtained which better performance. Therefore, the use of the waste from the production of Scheelite is feasible due to the durability parameters (water absorption and porosity), sustainability, and the good results of the resistance of the concrete
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O desenvolvimento das grandes cidades tem gerado um dos maiores desafios ambientais enfrentados na atualidade, que é a gestão eficaz de resíduos sólidos. A grande variedade e quantidade dos resíduos produzidos diariamente, tem tornado a destinação ecologicamente correta e sustentável destes materiais cada vez mais difícil. Dentre os vários resíduos produzidos diariamente destacam-se os lodos oriundos de estações de tratamento de esgotos, denominados de lodos de esgoto, cuja destinação final segura tem sido discutida mundialmente em diversos estudos, tendo em vista que a tendência de geração deste tipo de resíduo tende a crescer com o aumento do saneamento das cidades. Uma forma amplamente difundida nos países desenvolvidos para destinação dos lodos de esgoto é a incineração destes materiais para posterior envio das cinzas geradas neste processo a aterros sanitários. Porém, tem-se estudado formas alternativas de disposição, destacando-se a utilização destas cinzas como adição mineral em concretos e argamassas de cimento Portland. Sabe-se que o desempenho de resíduos de incineração como adição mineral em matrizes cimentícias, depende em grande parte da capacidade de atuação destes materiais como elementos pozolânicos ou como fileres, podendo estas características serem influenciadas pela temperatura de queima ao qual estes resíduos foram submetidos. Neste sentido, verificou-se com esta pesquisa a influência da temperatura empregada na queima dos lodos sépticos no índice de atividade pozolânica (IAP) das cinzas geradas como resíduo deste processo, aqui denominadas de cinzas de lodo séptico (CLS), sendo em seguida, avaliadas as implicações técnicas e microestruturais da utilização deste resíduo em teores de 10%, 20% e 30% como adição mineral em concretos de cimento Portland. Os resultados obtidos demonstraram não haver alterações significativas no IAP das CLS em decorrência da temperatura utilizada durante o processo de queima dos lodos de esgoto. Além disso, verificou-se que embora a utilização das CLS tenham provocado diminuição da trabalhabilidade dos concretos para todos os teores de incorporação, estas melhoraram a resistência mecânica à compressão, o índice de vazios, a absorção de água e o comportamento microestrutural dos concretos contendo 10% e 20% de resíduo
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The construction industry is responsible for generating a lot of waste because of their activities. Consequently, it is noticeable the occurrence of environmental problems in terms of its disposal in inappropriate places. Faced with this problem, some studies have been conducted with the aim of developing technologies and alternatives for recycling construction and demolition waste (CDW), motivated by the scarcity of natural resources and reduction of environmental problems generated. The research aims to characterize the recycled aggregates derived from construction and demolition waste (CDW) produced in the Greater Natal-RN and analyze the performance of mortar coating produced with recycled aggregates. The study includes the chemical , physical and microstructural characterization of recycled aggregates , as well as conducting microscopic analysis and laboratory tests in the fresh state (consistency index , water retention , bulk density and content of entrained air ) and in the hardened state ( compressive strength , tensile strength in bending , water absorption by immersion and capillary , mass density and void ratio ) for mortars produced from different levels of substitution of aggregates ( 0, 20 %, 40 %, 60 %, 80 % and 100 %). The results were satisfactory, providing mortars produced with recycled aggregates, smaller mass density and dynamic modulus values as well as an increase in the rates of absorption and porosity. The tensile strength in bending and compression for TP1 (1:2:8) trait were lower for mortars produced with recycled aggregates and the best result was 20% for replacement. For the TP2 (1:8) mapping, there was an increase in resistance to traction and compression and the best result was for 100% replacement of natural aggregates by recycled. The experiments led to the conclusion that the technical and economic point of view that the mortars produced with recycled aggregates can be used in construction, only if there is an effective control in production processes of recycled aggregate and at the dosage of mortars
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Mangas 'Tommy Atkins' produzidas na região de Ibirá, São Paulo, foram pulverizadas na pré-colheita com cloreto de cálcio, nas concentrações de 0,0%, 2,5% e 5,0%, em três épocas de seu desenvolvimento (40; 60 e 90 dias após a floração) a fim de verificar a influência do cálcio na estrutura da parede celular destes frutos através de microscopia eletrônica de transmissão, imediatamente após a colheita e depois de 35 dias de armazenamento. Para fixar o material da polpa, utilizou-se metodologia descrita por Jacob e Gowanlock (1995). Nas condições experimentais, verificou-se que os frutos do tratamento-controle (sem cloreto de cálcio), no dia da colheita, já apresentavam desestruturação da parede celular e dissolução da lamela média (LM). A degradação da parede celular ocorre inicialmente na LM, levando à formação de espaços vazios bastante distintos, apresentando uma dissolução ainda maior, com o armazenamento prolongado (35 dias). Os frutos tratados com cloreto de cálcio a 5,0% apresentaram uma LM bem definida e ausência de espaços vazios, mesmo após o armazenamento, mostrando ser uma concentração efetiva na preservação da lamela média.
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A compactação do solo tem sido assunto de intensivas pesquisas nos últimos anos; no entanto, os mecanismos que implicam o processo de compactação dos solos agrícolas, ainda permanecem pouco conhecidos. A contribuição do tamanho de agregados do solo, bem como o efeito do teor de água e da pressão normal aplicada na compactação e pressão de pré-compactação do solo, foi investigada em um Nitossolo Vermelho eutrófico. Amostras de solo deformado, constituídas por agregados menores que 2,5 mm e de 9,3 a 19,4 mm, foram submetidas a ensaio de compressão uniaxial drenado. O índice de vazios e a pressão de pré-compactação foram avaliados. Os resultados obtidos mostram que o tamanho de agregados teve efeito no processo de compactação do solo. A mudança da compactação do solo pode ser prevista em função do estado inicial do solo, da pressão aplicada e do teor de água.
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Dois condicionadores químicos, a carboximetilcelulose, nas dosagens de 0,1% e 0,25% em relação ao peso do solo seco, e o silicato de sódio, de relação sílica-álcali igual a 3,2, a 0,6% e 1,2% em peso, foram pesquisados quanto aos seus efeitos sobre os índices físicos dos solos argiloso e barro arenoso empregados neste trabalho. Os dados obtidos foram estatisticamente analisados e os resultados permitiram que se chegassem a algumas conclusões. O tratamento 0,25% de carboximetilcelulose diminuiu o peso específico aparente seco e aumentou, consequentemente, o índice de vazios e porosidade dos solos estudados. O efeito dos tratamentos 1,2% de silicato de sódio e 0,1% de carboximetilcelulose sobre o peso específico aparente seco dos solos argilosos e barro arenoso, respectivamente, foi semelhante ao do tratamento 0,25% de carboximetilcelulose.