763 resultados para areia grosseira


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Tese de doutoramento, Geologia (Hidrogeologia), Universidade de Lisboa, Faculdade de Ciências, 2016

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A incorporação de pigmentos na composição do betão é uma técnica aplicada como alternativa arquitetónica à pintura ou colocação de revestimentos em edifícios. Tratando-se de um betão à vista importa considerar cuidados adicionais na sua aplicação para assegurar a homogeneidade e qualidade do acabamento superficial. Utilizando betões autocompactáveis, não só a homogeneidade do material é aumentada devido à eliminação da compactação, como também o acabamento superficial é melhorado devido à maior capacidade de preenchimento dos moldes que estes betões apresentam. Neste trabalho dimensionam-se cinco composições de betão autocompactável colorido utilizando agregados britados vulcânicos correntemente utilizados no fabrico de betão na Região Autónoma da Madeira. Para o dimensionamento dos betões, realizaram-se vários estudos em pastas, de seguida em argamassas e finalmente em betões. Com o estudo das pastas obtiveram-se as primeiras informações sobre o efeito da introdução de pigmentos. Depois estudaram-se argamassas que continham o mesmo volume de areia relativo mas incorporando pastas com diferentes cores. Identificaram-se as pastas que conduziam a argamassas com propriedades reológicas semelhantes às da argamassa da composição considerada como referência. Nos betões começou-se por produzir uma composição de betão autocompactável de referência que foi caracterizada em termos de autocompactabilidade pelos ensaios de espalhamento, caixa L, funil V e segregação. Finalmente, realizaram-se composições de betões coloridos cujos conteúdos em agregados e finos eram os mesmos que os da composição de referência mas substituindo parcialmente o volume de água por igual volume de pigmentos. Os resultados mostraram que a incorporação de pigmentos conduz a uma ligeira perda de trabalhabilidade, sendo essa perda de trabalhabilidade facilmente compensada com um aumento da dosagem de superplastificante, cujo volume adicionado é substituído pela remoção de igual volume de água.

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A incorporação de pigmentos na composição do betão é uma técnica aplicada como alternativa arquitetónica à pintura ou colocação de revestimentos em edifícios. Tratando-se de um betão à vista importa considerar cuidados adicionais na sua aplicação para assegurar a homogeneidade e qualidade do acabamento superficial. Utilizando betões autocompactáveis, não só a homogeneidade do material é aumentada devido à eliminação da compactação, como também o acabamento superficial é melhorado devido à maior capacidade de preenchimento dos moldes que estes betões apresentam. Neste trabalho dimensionam-se cinco composições de betão autocompactável colorido utilizando agregados britados vulcânicos correntemente utilizados no fabrico de betão na Região Autónoma da Madeira. Para o dimensionamento dos betões, realizaram-se vários estudos em pastas, de seguida em argamassas e finalmente em betões. Com o estudo das pastas obtiveram-se as primeiras informações sobre o efeito da introdução de pigmentos. Depois estudaram-se argamassas que continham o mesmo volume de areia relativo mas incorporando pastas com diferentes cores. Identificaram-se as pastas que conduziam a argamassas com propriedades reológicas semelhantes às da argamassa da composição considerada como referência. Nos betões começou-se por produzir uma composição de betão autocompactável de referência que foi caracterizada em termos de autocompactabilidade pelos ensaios de espalhamento, caixa L, funil V e segregação. Finalmente, realizaram-se composições de betões coloridos cujos conteúdos em agregados e finos eram os mesmos que os da composição de referência mas substituindo parcialmente o volume de água por igual volume de pigmentos. Os resultados mostraram que a incorporação de pigmentos conduz a uma ligeira perda de trabalhabilidade, sendo essa perda de trabalhabilidade facilmente compensada com um aumento da dosagem de superplastificante, cujo volume adicionado é substituído pela remoção de igual volume de água.

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Among the species of freshwater shrimp being cultivated, Macrobrachium rosenbergii stands out. Knowledge about the behavior of this species and the influence of certain factors on its development can help optimize management practices and minimize the likely impacts shrimp farming has on the environment and the animals themselves. The objective of this study was to characterize the species' behavior during early stages of development under different stocking densities over a 24-hour cycle. Ten day old postlarvae were transferred from the Jundiaí School of Agriculture (EAJ - Escola Agrícola de Jundiaí) in Macaíba (RN), Brazil to the Shrimp Behavior Laboratory (LSPR - Laboratório de Estudos do Comportamento do Camarão) at the Federal University of Rio Grande do Norte (UFRN), where they were weighed and measured. Eight aquaria with constant temperature, aeration and filtration, and subjected to a12 h light/12 h dark cycle were used for each experiment. Each aquarium also contained two shelters made of bricks and the water quality was monitored weekly. Behavioral observations were made at two densities: 25 individuals/m-² and 40 individuals/m-². The methods for recording behaviors were: behavioral sampling – enter and leave the shelter, exploring on the substrate, exploring in the water column, move away, attack, pursuit and cannibalism; scan sampling - inactivity, feeding, exploration, digging, swimming, cleaning and staying in the shelter. Observations were made during a 15 minute period/per aquarium at a frequency of 4 times daily, for 4 days/week, and over 4 weeks. Food was provided 2 times/day for each aquarium population, immediately before the 1st and 3rd observation periods. Our results demonstrate that at high density, there is an increased frequency of agonistic behavior; during the light phase, there is a greater frequency of behaviors that result in less exposure (inactivity, cleaning and staying in the shelter); during the dark phase, there is an increased frequency of behaviors that result in greater exposure (feeding, exploration, swimming and digging); at times of feed offer, there is an increased frequency of leaving the shelter, moving away, pursuit, feeding, exploration and swimming. At low density, the animals showed a lower frequency of agonistic behaviors, greater weight gain and higher growth rates, which indicates that this is a more favorable growing environment for cultivation and when applied, can generate better living conditions, favor survival rates and increase management success

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This work aims to demonstrate the feasibility of a ceramic composite containing fiber in the rubber manufacturing interlocking blocks. Gravel, sand, cement, rubber and fiber: the processes of manufacture and assembly of blocks produced and the various formulations studied with different proportions between the constituent elements were addressed. Mechanical properties were determined for the different formulations, compressive strength, diametral compressive strength, water absorption and apparent density, obeying the rules related to each property. It was concluded that the addition of rubber fiber gave the concrete studied resistance lower than conventional concrete which can be verified on the microstructural analysis obtained by SEM, which revealed the presence of pores and the low adhesion between the fiber and the matrix compression (tire fiber / cement paste). The composite of more viable tire BCPB1 (1/2) fiber can be used in places requests as light squares, pavements, roads and other cycle as well as in the manufacture of the curb and gutter, by having compressive strength in about 20 MPa

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The contamination of water sources of public drinking by waste originated by anthropogenic activities has brought various risks to human health. Among the consequences of such activities can highlight the bloom of microalgae and cyanobacteria, which have the potential to produce toxins dangerous to humans, and the presence of humic substances that are generated by the decomposition of natural organic matter (NOM), such as vegetation. When found in water sources for public supply, present negative aspects conferring high color, odor and taste. The double filtration technology has good efficiency in water with the presence of cyanobacteria and different quality variations. Therefore, this study aimed to evaluate the behavior of the technique of double filtration with pre-oxidation for water purifiers the lagoon of Extremoz-RN, which currently has high concentrations of cyanobacteria. The research is summarized in four phases: the first phase turned to static tests in jarteste equipment in the laboratory and subsequent phases were tested in the Pilot Plant of Double Filtration. For the second and third stage filtration rates were tested filtration rates of 120 and 180 m3 / m2 .day for ascending boulders filters and 160 and 240 m3 / m2 .day in the filters in quick sand descendants. The last phase aimed to evaluate the double filtration with pre-oxidation. The results demonstrated that the system could produce double filtration in all trials of good quality water according to the Decree nº. 2914/11 of the Ministry of Health. The use of preoxidation favored the removal of microcystin and color at the end of the tests, reaching a percentage of color removal around 60%. The analysis of variance in the data, enabled prove that the filtration rates of 180 m3 / m2.d the gravel filter and 240 m3 /m2 .d in rapid filters, were the most significant for the removal of turbidity. The ascending filter of boulder 4 with particle size finer filter layer showed the best performance and the best means of turbidity and apparent color. The rapid filter downward 1 was more efficient in removing turbidity reaching removal about 100%

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The use of composite materials for the construction industry has been the subject of numerous scientific papers in Brazil and in the world. One of the factors that motivate this quest is the housing deficit that countries especially the third world face. In Brazil this deficit reaches more than 6.5 million homes, around 12% of all US households . This paper presents a composite that was obtained from waste generated in processes for the production of granite and marble slabs, cement, gypsum, sand, crushed EPS and water. These wastes cause great damage to the environment and are thrown into landfi lls in bulk. The novelty of the work is in the combined study thermal, mechanical and acoustic composite obtained in real situation of rooms that are part of an experimental housing. Many blocks were made from cement compositions, plaster, foam, sand, marb le and / or granite, preliminary tests of mechanical and thermal resistance were made by choosing the most appropriate proportion. Will be given the manufacturing processes and assembly units 500 units 10 x 80 x 28 cm produced for the construction of an ex perimental home. We studied what kind of block and residue, marble or granite, made it more feasible for the intended purpose. The mechanical strength of the produced blocks were above 3.0 MPa. The thermal resistance of the blocks was confirmed by the maxi mum temperature difference between the inner and outer walls of rooms built around 8.0 ° C. The sound absorption for optimal room was around 31%. Demonstrated the feasibility of using the blocks manufactured with composite material proposed for construction.

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Government efforts have found some obstacles in achieving a better infrastructure regarding environmental preservation requirements. There is a need to develop new techniques that leave the big exploitation of environmental resources. This study measures the evaluation of the behavior of a composite formed by lateritic soil mix and tire buffings. In this way, a road embankment model was developed to assess the bearing capacity of the composite. This study measured the load capacity of the composites with 0%, 10%, 20% and 40% rubber mixed with the soil, by weight, iron plate loading tests on a simulated embankment in a metal box of 1.40 x 1.40 x 0.80 m. After four compaction layers of the composite, a plate test was performed, and then stress-settlement curves were obtained for the material. The embankments with 20% and 40% rubber content was difficult to compact. There was a significant reduction in the load capacity of the soil-plate system with increasing rubber content. The composite with the lowest loss of bearing capacity in relation to the reference soil was the one with a χ = 10%. In the load capacity tests, another aspect noted was the bearing capacity in terms of CBR. The results also show a gradual decrease in bearing capacity in the composites as with the rubber incorporation content increases. As in the plate load tests, the composite that had the lower bearing capacity loss was also that with 10% content.

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Systems of incised valleys have been studied in different continental shelves, including the Brazilian continental margin. The interest to characterize this feature is given by the information that it can provide variations on sea level, as well as the ability to host economically significant quantities of hydrocarbons in reservoirs located in deposits filling of the incised valleys. This thesis has the overall objective to characterize the morphology and sedimentary cover of the incised valley Apodi-Mossoró, located in the Northern Continental shelf of Rio Grande do Norte state, adjacent to Areia Branca city. The methodology included the integration of satellite imagery, bathymetric data, sedimentological data, shallow seismic, and the identification of foraminifera. The results indicate that the ApodiMossró incised valley is currently formed by two channels, shallow channel and deep channel, which have distinct morphological and sedimentological characteristics. The deep channel has connection with one of the heads of the Apodi Canyon, located in the slope area. The acquisition, processing and interpretation of shallow seismic data allowed the recognition of the depositional surface, erosional surface, discordance, and sismofaceis. The erosional surface mapped from shallow seismic sections is possibly a indicative of an ancient surface of valley incision, where it would probably be associated with the limit Pleistocene/Holocene. Different sismofaceis were identified and reflect the rise in sea level with standards sometimes agradacional, sometimes progradational. The thickness of sediments on this surface was estimated at a maximum of 22m thick in the central portion of the incised valley. Statistically, there are differences between the adjacent continental shelf and channels, and between these channels, for the content of calcium carbonate, organic matter, sand and mud perceptual, except for the gravel grain size. The analysis of living and dead foraminifera showed the presence of fifty species distributed in regards to morphology, depth and type of sediment. Four type of seismic echocharacteres were identified and mapped, as well as their bedforms, indicating different sedimentary processes along the incised valley. The integration of results suggests an activation of the Apodi-Mossoró incised valley in the Late Pleistocene.

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The antimanicomial psychiatric reform is a process that seeks to deconstruct the exclusionary logic caused by hospitalizations, providing strategies for social reintegration of individuals. In this sense, the primary care through the Family Health Strategy - FHS comes progressively becoming strategic space in mental health interventions, configured as a field of practice and production of new modes of care. In this perspective, there has been a process of implementing this proposal in the Areia Branca City/RN, through the articulation of Psychosocial Care Network and the Family Health Strategy / ESF. However, this process has not been able to bring changes in practices. From the view that the relationship between mental health and primary care is a challenge currently being faced, that improving the care provided and the expansion of the access to services with guaranteed continuity of care depend on the effectiveness of this joint, established themselves as research objective: To investigate how is the relationship between the FHS team and CAPS team in care mental health in the town of Areia Branca - RN from the speeches of professionals. And if you had specific purposes: 1) Know the demand in existing mental health in the town of White Sand - RN served by FHS; 2) Identify limits and difficulties in the relationship between the ESF teams and CAPS; 3) Identify potential for linkages between ESF teams and CAPS for the establishment of local RAPS. This was a descriptive, exploratory study with a qualitative methodological design, whose subjects were professionals from the Family Health Strategy, professionals Psychosocial Care Center and responsible for the conduct / management of mental health in the municipality. The research tools used informal observations, semistructured interviews and focus groups were used. The data obtained were analyzed for the content analysis of Bardin, allowing discuss the relevance of the theoretical framework with data obtained through observation and interpretation of the relationship between the Family Health Strategy and the network of Psychosocial Care in Areia Branca-RN. On the one hand, there was strong demand for mental health arising from users and their families and / or caregivers. On the other, it was verified that although there is some progress with regard to perceptions of mental health, there are still practical, historical and contextually rooted, which act as barriers to effective response to this demand in view of deinstitutionalization. In this sense, it is considered important to emphasize that the teams of the Family Health Strategy should be trained to ensure the health practice with integrity and incorporating the mental health network in the municipality. This training must occur through continuing health education.

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In the last decades, analogue modelling has been used in geology to improve the knowledge of how geological structures are nucleated, how they grow and what are the main important points in such processes. The use of this tool in the oil industry, to help seismic interpretations and mainly to search for structural traps contributed to disseminate the use of this tool in the literature. Nowadays, physical modelling has a large field of applications, since landslide to granite emplacement along shear zones. In this work, we deal with physical modelling to study the influence of mechanical stratifications in the nucleation and development of faults and fractures in a context of orthogonal and conjugated oblique basins. To simulate a mechanical stratigraphy we used different materials, with distinct physical proprieties, such as gypsum powder, glass beads, dry clay and quartz sand. Some experiments were run along with a PIV (Particle Image Velocimetry), an instrument that shows the movement of the particles to each deformation moment. Two series of experiments were studied: i) Series MO: We tested the development of normal faults in a context of an orthogonal (to the extension direction) basin. Experiments were run taking into account the change of materials and strata thickness. Some experiments were done with sintectonic sedimentation. We registered differences in the nucleation and growth of faults in layers with different rheological behavior. The gypsum powder layer behaves in a more competent mode, which generates a great number of high angle fractures. These fractures evolve to faults that exhibit a higher dip than when they cross less competent layers, like the one of quartz sand. This competent layer exhibits faulted blocks arranged in a typical domino-style. Cataclastic breccias developed along the faults affecting the competent layers and showed different evolutional history, depending on the deforming stratigraphic sequence; ii) Series MOS2: Normal faults were analyzed in conjugated sub-basins (oblique to the extension direction) developed in a sequence with and without rheological contrast. In experiments with rheological contrast, two important grabens developed along the faulted margins differing from the subbasins with mechanical stratigraphy. Both experiments developed oblique fault systems and, in the area of sub-basins intersection, faults traces became very curved.

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The cactus pear has become over the years an important forage alternative for brazilian semiarid region, especially during long periods of drought. Despite its importance for agriculture, its cultivation has dispensed basic crop practices and fundamentals technical-scientific basis about its climatic requirements. Thus, the main objective of this study was to elaborate the agroclimatic zoning of cactus pear (Opuntia sp.) for the state of Paraíba. The agroclimatic zoning of cactus pear was based on climatic indicators outlined in the literature and climatological data of precipitation and temperature (mean, maximum, and minimum) from 97 locations in the state of Paraíba. According to the results, the region of ‘Borborema’ is the most favorable for the cultivation of cactus pear. The regions of ‘Agreste’, ‘Sertão’, and coastal part of Litoral may be used but with restrictions. However, the cultivation of cactus pear is recommended throughout the state of Paraíba, except the coastal part of the Litoral and the region around Areia. In both cases, the inability is due to excessive precipitation.

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Several studies have been developed regarding health risks associated with the recreational use of beaches contaminated with domestic sewage. These wastes contain various microorganisms, including Candida tropicalis, etiologic agent of both superficial infections such as systemic, as well as indicator of fecal contamination for the environment. In this context, the objective of this study was to characterize C. tropicalis isolates from the sandy beach of Ponta Negra, Natal, Rio Grande do Norte, Brazil, regarding the expression of in vitro virulence factors, adaptation to osmotic stress and susceptibility to antifungal drugs. We analyzed 62 environmental isolates of C. tropicalis and observed a great variation between them for the various virulence factors evaluated. In general, environmental isolates were more adherent to CEBH than C. tropicalis ATCC13803 reference strain, besides the fact they were also highly biofilm producers. In relation to morphogenesis, most isolates presented wrinkled phenotype in Spider medium (34 isolates, 54.8 %). When assessing enzyme activity, most isolates had higher proteinase production than C. tropicalis ATCC13803 reference strain. In addition, 35 isolates (56.4 %) had high hemolytic activity (hemolysis index > 55). With regard to C. tropicalis resistance to osmotic stress, 85.4% of the isolates were able to grow in a liquid medium containing 15% sodium chloride, corroborating to high survival capacity described for this yeast at marine environment. Finally, with regard to sensitivity to antifungal drugs, it was observed high resistance to the azoles tested, with the occurrence of the "Low-high" phenomenon and similar effect to the paradoxical growth which occurs to the echinocandins. For the three azoles tested we verified that 15 strains were resistant (24.2 %). Some strains were also resistant to amphotericin B (14 isolates, 22.6 %), while all of them were sensitive for the echinocandins tested. Therefore, our results demonstrate that C. tropicalis isolated from the sand of northeast of Brazil can fully express virulence attributes and showed a high persistence capacity on the coastal environment, in addition of being significantly resistant to most applied antifungals in current clinical practice. This constitutes a potential health risk to visitors of this environment, especially immunocompromised individuals and those with extreme age range.

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O NAVSTAR/GPS (NAVigation System with Timing And Ranging/Global Po- sitioning System), mais conhecido por GPS, _e um sistema de navegacão baseado em sat_elites desenvolvido pelo departamento de defesa norte-americano em meados de 1970. Criado inicialmente para fins militares, o GPS foi adaptado para o uso civil. Para fazer a localização, o receptor precisa fazer a aquisição de sinais dos satélites visíveis. Essa etapa é de extrema importância, pois é responsável pela detecção dos satélites visíveis, calculando suas respectivas frequências e fases iniciais. Esse processo pode demandar bastante tempo de processamento e precisa ser implementado de forma eficiente. Várias técnicas são utilizadas atualmente, mas a maioria delas colocam em conflito questões de projeto tais como, complexidade computacional, tempo de aquisição e recursos computacionais. Objetivando equilibrar essas questões, foi desenvolvido um método que reduz a complexidade do processo de aquisição utilizando algumas estratégias, a saber, redução do efeito doppler, amostras e tamanho do sinal utilizados, além do paralelismo. Essa estratégia é dividida em dois passos, um grosseiro em todo o espaço de busca e um fino apenas na região identificada previamente pela primeira etapa. Devido a busca grosseira, o limiar do algoritmo convencional não era mais aceitável. Nesse sentido, um novo limiar foi estabelecido baseado na variância dos picos de correlação. Inicialmente, é feita uma busca com pouca precisão comparando a variância dos cinco maiores picos de correlação encontrados. Caso a variância ultrapasse um certo limiar, a região de maior pico torna-se candidata à detecção. Por fim, essa região passa por um refinamento para se ter a certeza de detecção. Os resultados mostram que houve uma redução significativa na complexidade e no tempo de execução, sem que tenha sido necessário utilizar algoritmos muito complexos.

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Although efficient from a technical point of view, mortar layers that make up the traditional masonry coating (slurry mortar, plaster and plaster) have to be in contradiction with the new construction technologies and more efficient methods of consumption and work rationalization. From an environmental point of view, the recovery of waste into new composites for the building has been a growing strand of studies in the scientific community, may prove to be a cost-effective solution in some cases. Thus, this research proposes the development of a mortar Decorative Coating Monolayer (RDM), for use in facades, produced on site, incorporating tempered glass waste (RVT) in the cement matrix, as a partial substitute for aggregate. Therefore, we adopted the binder respect / aggregate of 1: 6 (by volume), consistency index 250mm ± 20, sand substitution levels of glass waste 20%, 50% and 80% and relative water / cement varied in many traits. Two additives were used, a polymer, styrene-butadiene-based, and other chemical, besides mineral and silica fume inorganic pigment in colors red, yellow and blue. Mechanical tests were carried out on fresh pasta and hardened, as well as for the applied coating on masonry, so as to demonstrate the feasibility of the material. In addition, it verified the adequacy of the RDM built environment by means of thermal tests. The results demonstrated the feasibility of the proposed RDM with significantly higher values when compared to norms, especially the dash-added replacement content of 20% and addition of pigment in red. Therefore, the study shows the scientific community as an incentive to the use of technological innovations in construction, increasing the range of alternatives available for housing production, with the proposition of a material that achieves the desired functionality and obtain environmental gain, and may be adopted on construction sites as an alternative industrialized mortars.