999 resultados para Ponte metálica. Aspectos históricos. Processos construtivos. Propriedades tecnológicas
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The industrial production of ornamental rocks and the burning of coffee husk generate waste that is discarded into the environment. However, with the study of the incorporation of these residues in ceramic products, may be found an alternative to reducing environmental impacts and detrimental effects on human health caused by its indiscriminate disposal of waste in nature. Thus, this work aimed to study the addition of ashes of the coffee husk and granite residue in matrix of red ceramic. The raw materials were dry milled and sieved to mesh 100. To characterize the raw materials were carried out analyzes of X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis (PSA), differential thermal analysis (DTA) and thermogravimetric analysis (TG). Six formulations were prepared where the clay content was kept constant (70%wt) and ashes contents and granite residue varied from 10, 15, 20 and 30%. Dilatometrics analyzes were performed at four selected formulations, containing them: 100% clay (A100); 70% clay and 30% ashes (A70C30); 70% clay and 30% granite residue (A70G30); and 70% clay, 15% granite residue and 15% ashes (A70G15C15). The samples were prepared by uniaxial compaction with pressure of 25 MPa, and fired at temperatures of 800°C, 850ºC, 900ºC, 950ºC, 1000ºC and 1100°C. Assays were performed to determine the linear shrinkage of burning (LSB), water absorption (WA), apparent porosity (AP), density (D) and tensile bending. Also were performed analyzes of X-ray diffraction (XRD) and scanning electron microscopy (SEM) of the samples fired. The formulations incorporating granite residue and/or ashes reached the required limits of water absorption according to NBR 15270-1 and NBR 15310 and tensile bending according to classical literature (SANTOS, 1989) necessary for the production of tiles and ceramic block for masonry sealing
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The production of waste from urban and industrial activities is one of the factors of environmental contamination and has aroused attention of the scientific community, in the sense of its reuse. On the other hand, the city of Salvador/Ba, with approximately 262 channels, responsible for storm water runoff, produces every year, by the intervention of cleaning and clearing channels, a significant volume of sediments (dredged mud), and thus an appropriate methodology for their final destination. This study aims to assess the influence of incorporation of these tailings in arrays of clay for production of interlocked block ceramic, also known as ceramic paver. All the raw materials from the metropolitan region of Salvador (RMS) were characterized by x-ray fluorescence, x-ray diffraction, thermal analysis (TG and TDA), particle size analysis and dilatometry. With the use of statistical experimental planning technique, ternary diagram was defined in the study region and the analyzed formulations. The specimens were prepared with dimensions of 60x20x5mm³, by uniaxial pressing of 30 MPa and after sintering at temperatures of 900°, 1000º and 1100ºC the technological properties were evaluated: linear shrinkage, water absorption, apparent porosity, apparent specifies mass, flexural rupture and module. For the uniaxial compression strength used cylindrical probe body with Ø 50 mm. The standard mass (MP) was prepared with 90% by weight of clay and 10% by weight of Channel sediment (SCP), not being verified significant variations in the properties of the final product. With the incorporation of 10% by weight of manganese residue (PFM) and 10% by weight of the Ceramic waste (RCB) in the mass default, in addition to adjusting the plasticity due to less waste clay content, provided increased linear firing shrinkage, due the significant concentration of K2O, forming liquid phase at low temperature, contributing to decreased porosity and mechanical resistance, being 92,5 MPa maximum compressive strength verified. After extract test leachate and soluble, the piece containing 10% of the PFM, was classified as non-hazardous and inert material according to NBR10004/04 ABNT. The results showed the feasibility on using waste, SCP, RCB and PFM clay mass, at temperatures above 900ºC, paver ceramic production, according to the specifications of the technical standards, so that to exceed the 10% of the PFM, it becomes imperative to conduct studies of environmental impacts
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Textile production has been considered as an activity of high environmental impact due to the generation of large volumes of waste water with high load of organic compounds and strongly colored effluents, toxic and difficult biodegradability. This thesis deals with obtaining porous alumina ceramic membranes for filtration of textile effluent in the removal of contaminants, mainly color and turbidity. Two types of alumina with different particle sizes as a basis for the preparation of formulation for mass production of ceramic samples and membranes. The technological properties of the samples were evaluated after using sintering conditions: 1,350ºC-2H, 1,450ºC-30M, 1,450ºC-2H, 1,475ºC-30M and 1,475ºC-2H. The sintered samples were characterized by XRD, XRF, AG, TG, DSC, DL, AA, MEA, RL, MRF-3P, SEM and Intrusion Porosimetry by Mercury. After the characterization, a standard membrane was selected with their respective sintering condition for the filterability tests. The effluent was provided by a local Textile Industry and characterized at the entry and exit of the treatment plant. A statistical analysis was used to study the effluent using the following parameters: pH, temperature, EC, SS, SD, oil and grease, turbidity, COD, DO, total phosphorus, chlorides, phenols, metals and fecal coliform. The filtered effluent was evaluated by using the same parameters. These results demonstrate that the feasibility of the use of porous alumina ceramic membranes for removing contaminants from textile effluent with improved average pore size of 0.4 micrometre (distribution range varying from 0,025 to 2.0 micrometre), with total porosity of 29.66%, and average percentages of color removal efficiency of 89.02%, 92.49% of SS, turbidity of 94.55%, metals 2.70% (manganese) to 71.52% (iron) according to each metal and COD removal of 72.80%
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Among the industries, those that produce ceramic porcelain for use in construction industry and oil, during the exploration and production period, play an important role in the production of waste. Much research has been carried out both by academia and the productive sector, sometimes reintroducing them in the same production line that generated them, sometimes in areas unrelated to their generation, as in the production of concrete and mortar for the construction, for example, but each one in an isolated way. In this research, the aim is to study the combined incorporation of the waste drill cuttings of oil well and the residue of the polishing of porcelain, generated in the final stage of finishing of this product in a clay matrix, for the production of red pottery, specifically bricks, ceramic blocks and tiles. The clay comes from the municipality of São Gonçalo, RN, the drilling waste is from the Natal basin, in Rio Grande do Norte, and the residue of the polishing proceeds from a ceramic porcelain of the State of Paraíba. For this purpose, we used a mixture of a plastic clay with a non-plastic, in a ratio of 50% each, settling formulations with the addition of these two residues in this clay matrix. In the formulations, both residues were incorporated with a minimum percentage of 2.5% and maximum of 12.5%, varying from 2.5% each, in each formulation, which the sum of the waste be no more than 15%. It should be noted that the residue of the polishing of ceramic porcelain is a IIa class (not inert). The materials were characterized by XRF, XRD, TG, DTA, laser granulometry and the plasticity index. The technological properties of water absorption, apparent porosity, linear shrinkage of burning, flexural tensile strength and bulk density were evaluated after the sintering of the pieces to 850 °C, 950 °C and 1050 °C, with a burning time of 3 hr, 3 hr and 30 minutes, and 3 hr and 50 minutes, respectively, with a heating rate of 10 °C/minute, for all formulations and landing of 30 minutes. To better understand the influence of each residue and temperature on the evaluated properties, we used the factorial planning and its surfaces of response for the interpretation of the results. It was found that the temperature has no statistical significance at a 95% of reliability level in flexural tensile strength and that it decreases the water absorption and the porosity, but increases the shrinkage and the bulk density. The results showed the feasibility of the desired incorporation, but adjusting the temperature to each product and formulation, and that the temperatures of 850 °C and 950 °C were the one that responded to the largest number of formulations
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Rio Grande do Norte State stands out as one great producer of structural clay of the brazilian northeastern. The Valley Assu ceramic tiles production stands out obtained from ilitics ball clays that abound in the region under study. Ceramics formulation and the design of experiments with mixture approach, has been applied for researchers, come as an important aid to decrease the number of experiments necessary to the optimization. In this context, the objective of this work is to evaluate the effects of the formulation, temperature and heating rate in the physical-mechanical properties of the red ceramic body used for roofing tile fabrication of the Valley Assu, using design of mixture experiments. Four clays samples used in two ceramics industry of the region were use as raw material and characterized by X-ray diffraction, chemical composition, differential thermal analysis (DTA), thermogravimetric analysis (TGA), particle size distribution analysis and plasticity techniques. Afterwards, they were defined initial molded bodies and made specimens were then prepared by uniaxial pressing at 25 MPa before firing at 850, 950 and 1050 ºC in a laboratory furnace, with heating rate in the proportions of 5, 10 e 15 ºC/min. The following tecnologicals properties were evaluated: linear firing shrinkage, water absorption and flexural strength. Results show that the temperature 1050 ºC and heating rate of 5 ºC/min was the best condition, therefore presented significance in all physical-mechanical properties. The model was accepted as valid based of the production of three new formulations with fractions mass diferents of the initial molded bodies and heated with temperature at 1050 ºC and heating rate of 5 ºC/min. Considering the formulation, temperature and heating rate as variables of the equations, another model was suggested, where from the aplication of design of experiments with mixtures was possible to get a best formulation, whose experimental error is the minor in relation to the too much formulations
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Nowadays, industries from all sectors have great concerns over the disposition of the residues generated along the productive process. This is not different in the mineral sector, as this generates great volumes of residues. It was verified that the kaolin improvement industry generates great volumes of residue basically constituted of kaolinite, muscovite mica and quartz, which are basic constitution elements to formularisations of ceramics masses to the production of covering of stoneware tiles type. This happens because the methodology applied to the improvement process is still very rudimentary, what causes a very low yield, only ¼ from all the material volume that enters the improvement process, in the end, is marketable. The disposal of this residue, in a general way, causes a very big negative environmental impact, what has justified the researches efforts aiming to find a rational solution to this problem. In this way, the intention of this present work is the utilization of this residue in the manufacture of products to high quality ceramics covering, stoneware tiles in an industrial scale. For this purpose, the influence of the addition of the residue to a standard ceramics mass used by a ceramics sector company, already established in the market, with the intention of verifying the possibility of use of this residue as the mass complementary raw material and even the possible partial or total substitution of one of the components of the mass for the raw material in evidence will be studied. To the accomplishment of this work, the kaolin improvement residue generated by an industry of exploitation and improvement of kaolin, located in the region of Equador-RN, in the levels 1,2,4,8, 16 and 32% will be added to the standard mass already used for the production of stoneware tiles. The raw materials used, kaolin residue and the standard mass, were characterized through DRX, FRX, DTA, TGA and dilatometry. After the sintering of the bodies of test, tests of water absorption, apparent porosity, post burning linear retraction, apparent specific mass and flexural strength (3 point bending) were realized to determinate the technological properties of these materials. The results show the studied residue can be considered raw material of great potential to the industry of floor and ceramics covering of the stoneware tiles type
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Se describe y analiza el cultivo y desarrollo del poema en prosa en las letras costarricenses, considerando que no ha sido objeto de suficiente atención por parte de la crítica. Una vez expuestos los aspectos históricos, conceptuales y teóricos, y la procedencia europea de esta modalidad discursiva, se exploran sus manifestaciones desde sus orígenes, a finales del siglo XIX, y el desarrollo posterior hasta sus manifestaciones en la literatura contemporánea.The development and evolution of prose poetry in Costa Rica is described and analyzed in view of the fact that critics have not given it the attention it deserves. A discussion of historical, conceptual and theoretical aspects, together with the European origins of this genre, provides the basis to explore its appearance around the end of the 19th century, and its later development up to the present time.
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La presente investigación se originó debido a que no existe un instrumento informativo que le permita a los auxiliares de la función pública aduanera conocer en gran medida los avances, procedimientos, normativa técnica y legal que han dado origen a la unión aduanera centroamericana en la región, ya que en la actualidad los auxiliares de la función pública aduanera juegan un papel muy importante en el ámbito nacional, en representación de los importadores y exportadores, por la razón mencionada anteriormente es necesario que estén debidamente informados y actualizados sobre el tema. Por tal motivo se elaboró un instrumento informativo que sirve como herramienta de apoyo a los auxiliares de la función pública aduanera en el tema antes citado. El objetivo trazado para la ejecución del trabajo es facilitar un instrumento informativo, que su contenido se muestre claro y sencillo, los procedimientos aduaneros, la normativa técnica y legal a raíz de la unión aduanera centroamericana. Para fundamentar la investigación se utilizó la indagación bibliográfica tanto nacional como internacional relacionada en aspectos históricos, procedimientos y normativa vigente. La metodología utilizada se realizó por medio del enfoque hipotético deductivo, comprobando la deficiencia en el conocimiento de los auxiliares de la función pública aduanera sobre la unión aduanera centroamericana. Teniendo en cuenta que la investigación generó resultados y de los cuales se partió para plantear una alternativa de solución a la problemática. También se recopiló información de campo en la que se elaboraron encuestas basadas en la bibliografía, hipótesis, las variables y finalmente en el planteamiento del problema; esto con el propósito de recolectar información para la elaboración de un material que contribuya al aumento del conocimiento de los auxiliares de la función pública aduanera en el tema en estudio. Uno de los resultados fundamentales obtenidos fue comprobar que la existencia de un instrumento informativo como apoyo a los auxiliares de la función pública aduanera ayudará a estos en el ejercicio de su profesión. Además se verificó que éstos, no se encuentran debidamente actualizados. Dado que las instituciones responsables no brindan la información necesaria y no cuentan con los medios prácticos y accesibles sobre los avances que van surgiendo referentes a dicho tema. Es por eso que se recomienda hacer uso de herramientas más viables para que los auxiliares de la función pública aduanera puedan tener acceso a dicha información.
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34 p.
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100 hojas : ilustraciones, fotografías a color.
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El interés de este caso de estudio es reflexionar sobre los procesos participativos en la formulación de instrumentos de planeamiento urbano y sus efectos en la gestión de las ciudades, particularmente en el espacio público. Esto se realiza partir de una revisión normativa en el presente y de algunos aspectos históricos de los procesos de “Participación Ciudadana” y del concepto de “Espacio Público” como escenarios propicios para que la ciudadanía aporte en las decisiones de planificación. Además, se plantea una revisión de cómo estos se constituyen en elementos estructurantes de la ciudad que la dotan de identidad, referentes simbólicos y apropiación ciudadana. Para este efecto, se realizó un balance de la estrategia de gestión social y participativa propuesta por el Plan Maestro de Espacio Público de 2005, con el fin de resaltar la importancia de la participación ciudadana en la gestión de los instrumentos de planificación con los que cuenta la ciudad y sus resultados en la gestión de espacio público en Bogotá.
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Desde o final do século XIX, estudiosos das mais diversas regiões do mundo vêm oferecendo valiosas contribuições visando o melhor entendimento sobre gênese e evolução das paisagens. Observa-se, porém, que além da preocupação em reconstituir a história de antigos ambientes, há ainda o desafio do prognóstico quanto ao futuro das formas atuais. Dentro desta perspectiva, surgiram os modelos evolutivos aqui discutidos: o de Pedimentação e Pediplanação (proposto por King na década de 50), o de Equilíbrio Dinâmico (sugerido por Gilbert no final do século XIX e retomado por Hack na década de 60), e o Probabilístico (difundido por Leopold e colaboradores na década de 60). Cada um destes modelos reflete tanto as tendências intrínsecas a Geomorfologia, quanto as influências externas a este campo, ou seja, as visões de mundo das ciências em seu aspecto mais amplo, como também as tendências filosóficas e políticas de uma época. Deve-se, portanto, enfatizar que, tendo cada uma das percepções teórico-conceituais prestigiado mais determinados aspectos de processos específicos, cada uma delas ofereceu importantes contribuições, de modo que nenhuma pode ser considerada absoluta. Todas estão presentes direta ou indiretamente, e em maior ou menor proporção, nos trabalhos realizados pelos estudiosos do presente, em especial, geógrafos físicos.
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As espécies arbóreas em florestas tropicais possuem madeiras com muita variação sob o ponto de vista de suas propriedades tecnológicas. Portanto, é necessário que se conheça com mais detalhes as propriedades tecnológicas em relação as silviculturais, principalmente daquelas espécies com potencial para comercialização. Várias espécies nativas estão sendo plantadas, por apresentarem crescimento rápido, porém pouco se sabe a respeito de suas propriedades tecnológicas e a relação em cada sistema ou método de plantio e tratos culturais. Visando contribuir para aumentar as informações sobre a interação entre as propriedades tecnológicas e a Silvicultura, este trabalho teve por objetivo estudar a densidade básica da espécie Bagassa guianensis Aubl., em quatro espaçamentos, em plantio com 16 anos de idade, em área do Campo Experimental da Embrapa Amazônia Oriental, em Belterra. Estado do Pará. Os dados foram coletados em uma plantação de Bagassa guianensis Aubl. cobrindo uma área de 5,75 ha. Foram sorteadas, aleatoriamente, 8 árvores por espaçamento (3mx2m, 3mx3m, 3mx4m e 4mx4m). perfazendo urn total de 32 indivíduos. Considerando que a Bagassa guianensis Aubl. pode ter diversos usos, desde construção civil e naval ate móveis finos, os resultados deste trabalho mostram que a espécie pode ser plantada em diferentes espaçamentos, de acordo com o use final pretendido, já que não houve influência dos espaçamentos estudados na densidade básica da madeira.
INDICAÇÃO GEOGRÁFICA NO BRASIL: UM INSTRUMENTO PARA O DESENVOLVIMENTO RURAL SUSTENTÁVEL(UMA REVISÃO)
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O reconhecimento da qualidade dos produtos agrícolas em relação à sua origem é uma prática antiga, e que na atualidade é uma forma de diferenciá-los, podendo ser objeto de interesse de mercados capazes de valorizarem particularidades, permitindo a agregação de valor por meio da Indicação Geográfica (IG).A IG é uma ferramenta de desenvolvimento do setor agropecuário, porque ela embute e reconhece fatores ligados a origem, que vão além das condições naturais incluindo o fator humano e suas relações sociais como: conhecimento tradicional, segurança alimentar, fixação do homem no campo, agregação de valor, valorização do meio rural, que contribuem diretamente para o desenvolvimento rural sustentável. No conceito de IG destacam-se particularidades de diferentes produtos de inúmeras regiões, valorizando, então esses territórios, criando um diferenciador para o produto e território, que apresentam originalidade e características próprias, pois uma IG funciona como um instrumento aliando a valorização de um produto típico e seus aspectos históricos e culturais, a conservação da biodiversidade e o desenvolvimento rural.O Brasil é um país que apresenta grande diversidade de produtos agropecuários com qualidade diferenciada, que podem ter forte identidade com sua origem geográfica dada a influência de aspectos étnicos, culturais, geográficos e climáticos. No Brasil, a Lei nº 9279/1996 regulamentou, em seus artigos 176 a 182, a proteção de indicações geográficas para produtos e serviços. São alguns exemplos brasileiros: Vale dos Sinos, Vale dos Vinhedos, Pampa Gaúcho, Café do Cerrado e Cachaça de Paraty.
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O governo brasileiro instituiu em 2008, os Territórios de Cidadania como base de intervenção do Ministério de Desenvolvimento Agrário, visando o desenvolvimento dos territórios. Sergipe foi um dos estados pioneiros a implantar o planejamento com enfoque territorial. Nessa perspectiva o objetivo da nossa análise é verificar se há conformação dos Territórios de Cidadania com os processos construtivos das identidades territoriais e simbólicas do estado. O foco dessa análise são os assentamentos rurais de reforma agrária, entendendo esses assentamentos como territórios, com uma identidade social construída através da luta pela terra, dando origem a formas de resistência coletiva diante da opressão e da exclusão. Dentre os 186 assentamentos existentes em Sergipe elegemos um situado no Alto Sertão devido ás especificidades das reivindicações iniciais frente ao governo e as características de sua identidade social de resistência. Entendendo que a construção social da identidade sempre ocorre em um contexto marcado pelas relações de poder, o entrecruzamento das intervenções estatais com as representações internas do MST têm desvelado vários níveis de poder e multiterritorialidades.