1000 resultados para Concreto. Resíduo. Scheelita. Sustentabilidade
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The purpose of this work is to analyze the knowledge relationships that articulate in projects of maintainable rural development construction for the paraiban semi-arid, analyzing the farmers daily practices and their relationship with the technological practices spread by ONGs. We took as empirical object the rural community of Lajedo de Timbaúba, municipal district of Soledade-PB, located in the very small region of paraiban Curimataú. It is a community where registers one of the first cases of maintainable rural development planning in the state of Paraíba. The analysis was centered on the farmers experiences of life in sustainability experience, trying to understand how they acquire new knowledge and how they interact with them. In methodological terms, it was considered feasible to place the knowledge interaction between the farmers and technicians from ONGs by placing the analysis according to Paulo Freire s questioning (2006): extension or communication? To understand the farmers daily practices, it was resorted to the theoretical contribution by Michel de Certeau (2008) in order to discern a microresistance movement of inversion/rejection/changing by the farmers in relation to their external knowledge. Just from the theoretical point of view and resorting to the imaginary social by Cornelius Castoriadis (1982), it was considered the way of living of the farmers researched, having as reference the experience in the material and symbolic production of their lives. It became indispensable, therefore, not to dissociate the knowledge relationships between farmers and technicians from ONGs from the sustainability concepts, maintainable rural development, and rural extension. The results of the study revealed that the farmers from Lajedo de Timbaúba while dealing with the technological practices proposed by ONGs that work in the community, express those practices from their daily logic, and they constitute them in survival strategies that are inserted in their own idiosyncrasy. It was verified, therefore, that the external knowledge presented by the proposals of sociability alternatives with the droughts in the perspective of maintainable development while placed in the farmers daily relationship, they are judged as advantageous or disadvantageous when they are confronted with their peculiar way of doing their daily work. The technological practices are incorporated, denied, or recreated starting from evaluative criteria related to the preservation of the soil and to the economical and social reproduction of the unit of production of family agriculture
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The concrete for centuries constituted an essential structural element in the construction industry due to its relative ease of forming, before the weather durability, low cost, its lower maintenance compared to other materials such as steel. However, when the concrete is exposed to high temperatures tends to lose its mechanical characteristics, and may even result in loss of section, which undermines the stability and mechanical strength of structural elements. The pathologies resulting from exposure to elevated temperatures ranging from cracks, pops up chipping explosives (spalling). Recently, the technology of concrete is closely related to the study of its microstructure. The use of fibers added to concrete has been revealed as a solution to increase the mechanical strength of the concrete, it acts directly on the distribution of efforts to act in the play within the microstructure. In this work we used recycled PET fibers embedded in concrete with 15x2mm fck = 30MPa, water/cement ratio of 0.46, in works made for verification of mechanical strength of this mixture submitted to high temperature. The specimens of concrete with addition of PET fibers were tested after exposure to temperatures: ambient (30ºC), 100°C, 200°C, 300°C, 400°C, 600°C and 900°C. It was found that the concrete loses significant strength when exposed to temperatures above 300°C, however the use of fiber PET may delay the risk of collapse of structures for the formation of a network of channels that facilitate the escape of vapor 'water, reducing the pore pressure inside the structural element
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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With the increase in cement consumption, it has quickly become one of the inputs most consumed by mankind over the last century. This has caused an increase in CO2 emissions, as cement production releases large quantities of this gas into the atmosphere. Adding this fact to the growing consciousness of environmental preservation, it has led to a search for alternatives to cement to complement its derivatives, in the form of waste materials like the ashes. This research aimed to analyze the properties of mortars in fresh and hardened state with partial replacement of Portland cement by residual algaroba wood ash (CRLA) potteries produced by the state of Rio Grande do Norte. The CRLA was collected and sieved, where part of it was ground and characterized in comparison with that just sifted, being characterized according to its chemical composition, grain size, fineness, density, bulk density and index of pozzolanic activity. It was found that the wood ash does not act as pozzolan, and grinding it has not changed its characteristics compared to those just sifted, not justifying its use. Two traces were adopted for this research: 1:3 (cement: fine sand) and 1:2:8 (cement: hydrated lime: medium sand); both in volume, using as materials the CRLA just sifted, CP II F-32 Portland cement, CH-I hydrated lime, river sand and water from the local utility. For each trace were adopted six percentages of partial replacement of cement for wood ash: 0% (control) 5%, 7%, 10%, 12% and 15%. In the fresh state, the mortars were tested towards their consistency index and mass density. In the hardened state, they were tested towards their tensile strength in bending, compressive strength and tensile adhesion strength, and its mass density in the hardened state. The mortar was also analyzed by scanning electron microscopy and X-ray diffraction. Furthermore, it was classified according to NBR 13281 (2005). The results showed that up to a content of 5% substitution and for both traces, the residual algaroba wood ash can replace Portland cement without compromising the mortars microstructure and its fresh and hardened state
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O resíduo da indústria processadora de goiabas vem sendo aplicado em algumas áreas, entretanto não é conhecido o seu efeito na fertilidade do solo. Foi realizado experimento em casa de vegetação, com o objetivo de avaliar o efeito da aplicação do resíduo da indústria processadora de goiabas na fertilidade do solo, tendo como planta-teste o milho. O delineamento experimental utilizado foi em blocos ao acaso, em esquema fatorial 5x2, com quatro repetições, combinando-se cinco doses do resíduo da indústria processadora de goiabas (0; 20; 40; 60 e 80 t ha-1) na presença e ausência de adubação mineral. A adição de resíduo da indústria processadora de goiabas propiciou aumento nos teores de P e K do solo. O resíduo da indústria processadora de goiabas é uma fonte de liberação lenta de N e P para as plantas.
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Informações sobre a mineralização de subprodutos são importantes para o correto manejo desses materiais em áreas agrícolas. Assim, objetivou-se avaliar a mineralização do nitrogênio proveniente do resíduo da indústria processadora de goiabas, aplicado em Argissolo cultivado com goiabeiras. Amostras do solo mais o subproduto foram acondicionados em frascos de polietileno com capacidade de 0,25 dm³. Foram pesados 100 g de solo mais o resíduo referente a cada tratamento (doses do subproduto: 0; 9; 18 e 36 t ha-1), sendo tal procedimento realizado em triplicata. O período máximo de incubação foi de 11 semanas, analisando-se as amostras nos seguintes tempos: 0; 7; 14; 28; 42; 56; 70; 84; 98; 112 e 126 dias. A umidade foi corrigida para 70% da capacidade de retenção de água do solo, sendo monitorada diariamente através de pesagens dos potes. Nos tempos estabelecidos realizou-se a desmontagem de três frascos correspondentes a cada tratamento, determinando-se o nitrogênio inorgânico. Pode-se afirmar que a mineralização do N ou a liberação é lenta, ou seja, não há rápida disponibilização de nitrogênio. No período avaliado, 126 dias, a fração média de mineralização foi de 23% e, a meia vida média de 73 dias.
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The aim of this work is the numerical simulation of the mechanical performance of concrete affected by Alkali-Aggregate Reaction or RAA, reported by Stanton in 1940. The RAA has aroused attention in the context of Civil Engineering from the early 80, when they were reported consequences of his swelling effect in concrete structures, including cracking, failure and loss of serviceability. Despite the availability of experimental results the problem formulation still lacks refinement so that your solution remains doubtful. The numerical simulation is important resource for the assessment of damages in structures caused by the reaction, and their recoveries The tasks of support of this work were performed by means of the finite element approach, about orthotropic non-linear formulation, and, thermodynamic model of deformation by RAA. The results obtained revealed that the swelling effect of RAA induced decline of the mechanical performance of concrete by decreasing the margin of safety prior to the material failure. They showed that the temperature influences, exclusively, the kinetics of the reaction, so that the failure was the more precocious the higher the temperature of the solid mass of concrete
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This study aimed to assess the Cleaner Production CP as corporate sustainable tool, through the multiple case studies within companies from Rio Grande do Norte State. In order to achieve this goal a research methodology approach was set. The initial stage of the research methodology was based on a literature review on which it was observed that the CP can be linked with corporate sustainable once it prevents pollution and reduces the operational risks among employees, community and environment. In addition, CP can useful for companies position within competitive position as well as being applied to process, products and services. In order to observe these factors, CP was used within food industry (Company 1), textile industry (Company 2) and in a car dealer (Company 3). Regarding the results, Company 1 changed its raw material as well as implementing housekeeping (control use of water, energy and condensed milk). In Company 2, it was observed the three levels of CP. In other words, housekeeping (e.g. cutting process and manipulation of chemical products), changing technology (high pressure washing machine) and internal and external recycling. In addition, Company 3 considered only level 3 external recycling. As consequence, it was observed that can be applied either within industry as well as service sector. Unfortunately, it was not possible to observe any social gains on a monetary basis. This is due to limitations of the CP methodology and study complexity. Therefore, it was observed improvements regarding to social, environmental and economic areas. Nevertheless, it is necessary more commitment from top level management in order to consider CP like effective sustainable tool
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We are observing, particurlarly in the last two decades an aggravation of social problems inherent in contemporary society, such as high rates of unereloyment and social exclusion. In this context, the social economy appears as an alternative to generate employment and income, especially for the country man through the production and distribution of developed products in a collective way where the actions of cooperation gain significant importance this study aims to determine how the collective actions affect the sustainability of cooperative socio-political and economic developments of the economy and so it was adopted a methodology of multiple case study in three organizations in the apiculture sector of Rio Grande do Norte the Beekeepers Association of São Rafael City (AAMSR); Beekeepers Association of Serra do Mel (APISMEL) and Family Agriculture Cooperative of Apodi (COOAFAP). To evaluate relationship in collaborative ventures solidarity it is constructed a matrix that identify and develop relationship in the organization and, to measure the level of sustainability of these ventures are calculated the indices of socio-political sustainability and economic sustainability. The research results shows a fully collaborative relationship in all cases based on factors such as effective communication between beekeepers involved/and also cooperated with these organization; availability of beekeepers to perform adjustments in production process; an organizational culture focused on collaboration and high level of situation described above and taking into account that the business of solidarity economy better positioned in the matrix of relationships are those that have best indices of sustainability, it is evidence the importance of collaborative relationships for the sustainability of joint ventures
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As a contemporary tendency, it is been evidenced that the environmental changes theme, already admitted as a concernment to international economical and political reality, is also gaining repercussion on industrial and business sector. Firms are implementing actions on trial to minimize their own greenhouse gases (GHG) emissions impacts. However, the great majority of those actions of Corporative Social-Environmental Responsibility (CSR) are referred only to direct emissions of the main production systems. Direct emissions are those derived of an isolate process, without considering the upstream and downstream processes emissions, which respond for the majority of emissions originated because of respective firm‟s production system existence. Because the greenhouse effect occurs globally and the GHG emissions contribute to the environmental changes independently of their origin, it must be taken into account the whole productive life cycle of products and systems, since the energy invested on resources extraction and necessary materials to the final disposal. To do so, it must be investigated all relevant steps of a product/production system life cycle, tracking all activities which emit greenhouse gases, directly or indirectly. This amount of emissions consists in the firm‟s Carbon Footprint. This research purpose is to defend the Carbon Footprint relevance and its adoption viability to be used as an Environmental Indicator on measurement/assessment of CSR. It has been realized a study case on Petrobras‟s seat unity at Natal-Brazil, assessing part of its Carbon Footprint. It has been used the software GEMIS 4.6 to do the emissions quantifying. The items measured were the direct emissions of the own unity vehicles and indirect emissions of offset paper (A4), energy and disposable plastic cups consumed. To 2009, these emissions were 3.811,94 tCO2eq. We may conclude that Carbon Footprint quantification is indispensable to the knowledge of real emissions caused by a productive process existence, must serving as basis to CSR decisions about the environmental changes reversion challenge
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The fishing is made possible by the handiwork of a fisherman, not using appliances that achieve the same levels of industrial fishing productivity and not causing environmental impacts on fish stocks with the same intensity. The adoption of sustainability practices in this type of fishing has been requested for the achievement of environmental and socioeconomic improvements, since its production has been decreasing over the years and overfishing has led to reduced stocks also stand out environmental aggressions such as pollution. Thus, this research aims to analyze the interference of environmental aspects/impacts that permeate the activity performed by fisherman on the beach of Ponta Negra, Natal-RN, in order to propose recommendations for environmental sustainability. We used a methodology based on the ergonomic work analysis (WISNER, 1987; GUERIN, 2001; VIDAL, 2008) using techniques such as observational and interactional observation protocols, photographs, videos, conversational action, and listening to verbalizations. To understand the vulnerability of the environment in which the activity is carried fisherman and the interferences that it suffers, we used the study of environmental aspects/impacts (SÁNCHEZ 2008). As a result, it appears that from the observations located and reports raftsmen, changes in the sea, the search for new fishing grounds farther from the coast, reducing fishery production, waste generation and pollution of the workplace, and the difficulty in docking rafts, factors arising from the pressures both for society as Seen by fisherman, denoting the necessity of drawing up recommendations and actions proposed by management activity by promoting discussion among raftsmen and accountable institutions, and training through workshops on environmental education, aiming to positive changes in the activity fisherman from Ponta Negra and the environment in which raftsmen are inserted in order to seek a sustainable activity, preserving its characteristics
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The experiment was conducted at UNESP/FCAV, Jaboticabal, SP, with the objective of evaluating the influence of the rest period and height of the residue post-grazing on the dry matter mass, morphologic composition and on the chemical composition of the Tanzania-grass pre-grazing condition, under rotational grazing. The treatments consisted of the combination of two rest periods (25 and 35 days) and two residue height post-grazing (30 and 50 cm), as a complete randomized design in factorial arrangement 2 x 2, with three replications, with the grazing cycles considered as sub plots. The herbage mass of stem, leaves, dead material and the leaf: stem ratio were significantly influenced (P<0.05) by the grazing cycles. The percentage of CP in the leaf and stem and the NDF in the stem, leaf and whole plant were influenced positively (P<0.05) by the grazing cycles. It was observed that the short rest periods associated with the smallest residue height post-grazing presented the best results in terms of herbage mass and chemical characteristics of the herbage.
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Foi avaliada a digestibilidade in vitro/gás da matéria seca (MS) de quatro volumosos, exclusivos e suas combinações, na proporção de 50% na MS. Foram incubados 100 mg de amostra por tratamento, em triplicatas, em 48 h de digestão. As digestibilidades da MS e a produção de gás foram: cana-de-açúcar = 60,6%, 17,3 mL; cana-de-açúcar + silagem de milho = 63,9%, 19,6 mL; cana-de-açúcar + capim-elefante com 60 dias = 60,5%, 16,9 mL; cana-de-açúcar + capim-elefante com 180 dias = 48,6%, 14,1 mL; silagem de milho = 66,3%; silagem de milho + capim-elefante com 60 dias = 62,1%, 16,7 mL; silagem de milho + capim-elefante com 180 dias = 52,7%, 15,8 mL; capim-elefante com 60 dias = 61,5%, 16,9 mL; capim-elefante com 180 dias = 34,6%, 11,7 mL. Constatou-se que a combinação de volumosos, em alguns casos, pode diminuir a digestibilidade da MS dos volumosos de melhor qualidade.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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O objetivo neste trabalho foi avaliar o consumo, a digestibilidade total e parcial da matéria seca (MS) e dos nutrientes e os parâmetros ruminais de novilhos alimentados com rações à base de resíduo do processamento do caroço de algodão (RPCA) suplementado com levedura seca de cana-de-açúcar. Foram utilizados seis novilhos Nelore canulados no rúmen e duodeno, alimentados com rações compostas de 80% RPCA e 20% concentrado, composto de milho, ureia e levedura nos níveis de 0, 20 ou 40%. O delineamento experimental adotado para análise do consumo e da digestibilidade foi em blocos casualisados e a análise dos parâmetros ruminais foi em parcela subdividida. Os consumos e a digestibilidade de nutrientes não foram influenciados pela suplementação com levedura, fato que pode estar relacionado ao alto valor da fração C do resíduo do processamento do RPCA (44,51% MS) e à baixa fração proteica de lenta degradação da levedura, que impediu a sincronização energia/nitrogênio para maior degradação do resíduo. O pH do líquido ruminal decresceu linearmente nos animais mantidos com as dietas suplementadas com levedura. em todas as dietas, o pH e a concentração de N-NH3 foram adequados para o crescimento microbiano. As concentrações ruminais de acetato, propionato, butirato e ácidos graxos voláteis totais e a relação acetato:propionato não foram influenciadas pela suplementação com levedura. O resíduo do processamento do caroço de algodão é uma opção a ser utilizada no arraçoamento de bovinos.