Navegando por Assunto "Recursos Naturais"

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Acesso aberto (Open Access)
Caracterização de material compósito incorporado com fibras de bambu (Bambusa Vulgaris) e resíduos sólidos industriais para utilizacao como componente estrutural para a construcao civil
(Universidade Federal do Pará, 2020-03-12) SANTOS, Alessandro José Gomes dos; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
In the industry, the production of materials that bring less environmental impacts and that have high sustainability has been growing, mainly with regard to vegetable fibers and industrial waste. In this work, full isophthalic unsaturated polyester matrix, composites with bamboo vegetable fiber, composites with industrial residues (red mud, kaolin and copper) and hybrid composites with variation in the proportion of residues and fibers were made. The residues were used with granulometry of 100 MESH and the fibers in the lengths of 15mm and 30 mm, randomly arranged within the matrix. These fibers were used in natura and treated with 5% NaOH during the period of 2 (two) hours. The fibers were characterized in terms of their physical, mechanical and morphological properties. The composites were made by hand (hand lay-up) in the form of rectangular plates in metallic mold and pressed. The proportions of the mass fractions of the residues varied by 10%, 20%, 30% and 40%, whereas the mass fraction of fibers was varied by 1%, 2% and 3%. For the production of hybrid composites, the variation occurred up to the maximum saturation level of the matrix, with the proportion of residues / fibers of 10% / 3%, 20% / 3%, 30% / 3% and 40% / 3%, respectively. Bamboo fibers were chemically characterized by analyzing the levels of extractives, lignin and holocellulose. The residues were characterized mineralogically by means of X-Ray Diffraction (XRD). The composites were characterized physically (apparent porosity, water absorption and apparent specific mass), mechanically (traction, flexion and impact), flame retardancy and morphologically through Scanning Electron Microscopy (SEM) analysis. For physical characterization analyzes, 10 specimens (CP’s) were produced for each series. In the mechanical tests, 10 CP's were manufactured for the tensile tests, while for the flexion and impact tests, there were 8 CP's for each series. This same amount was used for the flame retardancy tests. After the physical tests, a small variation was observed with the addition of fibers and an increase in the Apparent Specific Mass with the addition of residues and fibers in the matrix. In the analysis by means of mechanical traction characterization, the best results of resistance limits in the values of 33.05 MPa were obtained for composites with 3% bamboo fibers treated with 15 mm in length and 33.11 MPa with bamboo fibers 30mm long without treatment. With the incorporation of waste, it reached a value of 40.25 MPa. In hybrid fractions the value reached 41.07 MPa with the addition of 20% kaolin residue / 3% bamboo fibers in the 15mm lengths with treatment. In flexion tests, the results were 150.94 MPa for the addition of treated 30mm fibers, 140.34 MPa for the addition of 20% kaolin residue and in the hybrids of 137.27 MPa for the addition of 30% kaolin residue / 3% bamboo fibers with 30mm treated. In the impact tests, the best results were 23.02 kJ / m² for the addition of 10% copper residue and 38.56 kJ / m² for the addition of 20% copper residue / 3% bamboo fibers with 30 mm long treated.
Acesso aberto (Open Access)
Impactos socioambientais de grandes projetos urbanos na Amazônia: ecologia política e cartografia para gestão de recursos naturais na Bacia da Estrada Nova, Belém/PA
(Universidade Federal do Pará, 2022-02-08) PANTOJA, Larissa Mourão; SILVA, Christian Nunes da; http://lattes.cnpq.br/4284396736118279; FARIAS, André Luís Assunção de; http://lattes.cnpq.br/5310171409459863
This work sought the understand and identify the social and environmental impacts at Estrada Nova´s hydrographic basin trough the urban interventions of macrodenage in an area considered peripheral, swampy and facing sanitary issues. From on-site verification, the characterization of the area, the official documents available by PROMABEN and the open interviews with community leaders and municipal public managers, several socio-environmental impacts were identified. Among them, the top five were listed, based on technical descriptions and the principle of natural resource management. As the objective of this work is the spatial identification of impacts, mapping techniques were used based on theoretical references of political ecology, in order to understand how the territory reproduces socio-spatial segregation and affects the most vulnerable, starting from the conception of the capitalist system, especially in peripheral areas. The qualitative method was used based on interviews with community leaders, as they represent a portion of the local population. Due to the pandemic of the new coronavirus, the individual interview with the community became unfeasible. For mapping the impacts, it used GPS navigation and photographic records. The study area was concentrated around. Bernardo Sayão Avenue, as it was the area affected by the PROMABEN works. As a result of this research, five maps were generated, being a general map of the impacts and four divided by sub-basin, with the purpose of spatial identification of the socio-environmental impacts, and thus contributing to the autonomy of the population through the recognition of the territory and the acceptance of these impacts that occur in a way that contradicts the way of life of the population and the local reality.
Acesso aberto (Open Access)
Mudança institucional e diversidade territorial na Amazônia Oriental Brasileira: o papel do mercado de terra como causa estrutural para o fenômeno do desmatamento
(Universidade Federal do Pará, 2018-11-14) SILVA, David Costa Correia; FERNANDES, Danilo Araújo; http://lattes.cnpq.br/2839366380149639
Deforestation is one of the main problems of the Amazon. The explanation of the causes of this environmental degradation tends to be done under the market relations (supply and demand), that is, with the use of neoclassical economic theory. By this theory, socio-environmental problems are reduced to market issues so that issues are considered externalities whose solution is the definition of property rights and the regulation of forms of use (command and control). In the case of the Amazon, deforestation would be linked to the demand for commodities that would act as an incentive to the devastation of new areas. However, the neoclassical view focuses only on immediate economic relations focused on the real economy (production, distribution and consumption). Thus, the neoclassical theory ignores the possibility of the earth being an asset with specific characteristics, with market and that can be transacted in the present or in the future, turning into a reason for speculation. Thus, this thesis raises the hypothesis that deforestation is a result of the constitution of land market. To test this hypothesis, this essay follows the theories of the New Economic Sociology and New Institutional Economics, which have the potential to explain the historical processes and the institutional changes that have taken place in the Amazonian territory that have resulted in the expansion of the agricultural frontier, expanding the possibilities of technological trajectories and in transformations in the institutional arrangements that helped to create the market for factors, including the land market, which is one of the drivers of Amazonian deforestation