Teses em Engenharia de Recursos Naturais da Amazônia (Doutorado) - PRODERNA/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/4045

O Doutorado Acadêmico inicou-se em 2006 e pertence ao Programa de Pós-Graduação em Engenharia de Recursos Naturais da Amazônia (PRODERNA) do Instituto de Tecnologia da UFPA (ITEC) da Universidade Federal do Pará (UFPA).

Navegar

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Aço inoxidável nanoestruturado produzido via soldagem a arco elétrico.
(Universidade Federal do Pará, 2021-07-08) LOAYZA, Cristhian Ricardo; BRAGA, Eduardo de Magalhães; http://lattes.cnpq.br/4783553888547500
Manufacturing methods of nanostructured stainless-steel composites (NSSC) have not yet been developed with industrial applicability. To overcome this shortage, the possibility of incorporating nanoparticles by electric arc welding was investigated, using a tubular rod filled with nanostructured flux composed of multi-walled carbon nanotubes (MWCNT) and 304L stainless steel particles. This flux was manufactured by two different methods: mechanical alloying (MA) and chemical treatment (CT) with hydrogen peroxide. The second showed more promising results using control of kinetic parameters of time and temperature, obtaining a lower degree of amorphous carbon, impurities, and crystalline defects, increasing their crystallinity and interaction of the nanotubes with the metallic matrix. MWCNT incorporation decreased the grain size by 64% when compared to the stainless-steel coating, possessing an austenitic matrix with carbide precipitation in the interdendritic spaces and grain boundaries. The microhardness increased 45% and the rate of erosion by vibratory cavitation decreased 64%, in relation to the AISI 304L coating. Additionally, XRD analyses showed a reduction of the γ{200} phase and a growth of γ{111} after the cavitation process. The method of manufacture of the nanocomposites proved to be economically viable and with the possibility of immediate application on a large scale.
Acesso aberto (Open Access)
Rejeito de caulim e caulim estéril amazônicos como fontes de Si e Al na obtenção de SAPO-34: síntese, otimização, influência de impurezas e aplicação em adsorção de corante
(Universidade Federal do Pará, 2021-05-27) PINHEIRO, Darllan do Rosário; PAZ, Simone Patrícia Aranha da
Kaolin waste from kaolin industry sedimentation ponds for paper and sterile kaolin or flint belonging to the same mine, in the Capim region, in northeastern Pará, were used in the synthesis of the SAPO-34 molecular sieve. The precursor materials and those produced were characterized by: DRX, FRX, TG-DSC-DTG, FTIR, ASEBET and MEV. First, the use of R-metakaolin as a precursor was evaluated, varying the SiO2 / Al2O3 ratio in the formulation of the SAPO-34 molecular sieve. The adjustment in the value of this molar ratio showed a positive effect on the formation of the desired zeolite, which showed formation of the CHA structure, in less time and with good thermal stability. In relation to the use of F-metakaolin, the effect of the amount of SDA and crystallization time (nucleation and crystal growth) on the formation of the CHA structure was evaluated and, later, that zeolitic product formed with less amount of SDA was used for a detail evaluation, in which the influence of Fe and Ti ions type impurities was studied. The results revealed a positive effect of the greater amount of SDA in the formation of SAPO-34 (CHA), but in a shorter time and, consequently, contribution in the Si distribution in the structure. When comparing the zeolitic products derived from F-metakaolin and a high purity kaolinitic pattern, the zeolitic product obtained from the kaolinitic sterile showed thermal resistance where the calcined product's DRX pattern maintained the CHA diffractometric profile, but with reduced crystallinity. It was also observed that before calcination, the zeolitic product obtained with F-metakaolin showed a smaller displacement to a 2θ (º) angle, indicating an increase in the interplanar distance with reference to the d101 plane, possibly due to interferences of the present impurities (Fe and ions). Ti), however after the calcination for decomposition of the SDA this displacement was not evidenced, thus indicating interference of the SDA used. That product considered the best, based on crystallochemical parameters, was used in the performance evaluation in methylene blue adsorption, which showed good adsorption capacity. In the evaluation of the adsorption kinetics, the pseudo-second order model (R2 = 0.998) was the one that best fit the experimental data. The optimization of the synthesis using tailings through the planning of Box-Behnken experiment and response surface methodology. It was concluded that the use of Amazon waste and/or flint kaolin is viable for the production of SAPO-34 zeolite (CHA).
Acesso aberto (Open Access)
O uso de fibra de juta (corchorus capsularis) no desenvolvimento de pás de turbina eólica de pequena escala para ventos de baixa intensidade
(Universidade Federal do Pará, 2023-10-17) CARDOSO, Robson Luis Baleeiro; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318; https://orcid.org/0000-0002-2738-6666
Natural fibers have growing potential for reinforcing polymer composites, representing a promising competitor to the glass and carbon fibres widely used in the construction of wind turbine blades, whose recyclability/disposability and high energy production costs have already been discussed in the main turbine production centres. On the other hand, the development of wind turbines for areas with winds of between 2 and 6 m/s, considered low speed, using the S1210 aerofoil profile could increase the energy generation potential of regions not originally eligible for the installation of large turbines. This study proposes evaluating the use of jute fiber (Corchorus capsularis) in the blade design of a small-scale wind turbine, considering aerodynamic and structural parameters. This project was developed incorporating Blade Element Momentum Theory (BEM), Classical Laminate Theory (TCL) and Extended Bredt-Batho Shear Flow Theory (EBSFT), in order to survey the elastic properties and enable the use of failure criteria. The composite blades were characterised in accordance with ASTM D 3039, ASTM D 638 and ASTM D 5379. The mechanical properties obtained, together with the elastic parameters of the cross-section, torsional stiffness, axial stiffness and flexural stiffness, of EIy 4.97 x 104 Nm2, EIz 1.45 x 106 Nm2, EI 9.47 x 104 Nm2 and GJ 1873.6 x 106 Nm2, respectively, demonstrated the feasibility of using jute fibre applied to the structural laminate in the construction of the blade, defined in accordance with the maximum stress failure criterion, presenting itself to compete with the glass fibres used today.
Acesso aberto (Open Access)
O Uso de polímeros reciclados na construção civil: uma proposta de habitação sustentável
(Universidade Federal do Pará, 2023-02-01) FERREIRA, Taiza Naiana da Silva; DIAS, Carmen Gilda Barroso Tavares; http://lattes.cnpq.br/2113791118142177
In recent decades, urban development has resulted in the unbalanced production of plastic materials as waste, waste that can be reused as raw material for a new production cycle. This work presents a proposal for sustainable housing with the use of floors, blocks for sealing with thermo acoustic blanket and sustainable tiles. For their preparation, rotational molding and compression molding equipment was assembled. Residues of polymers and natural fibers were used to make these constructive elements. The polymers used for the development of the floor were polystyrene (PS) disposable cups; ecological blocks were modeled and processed from post-consumer polypropylene (PP) and high-density polyethylene (HDPE) packaging; tiles were molded from discarded laminates; the floors became resistant to abrasion due to the presence of babassu fibers. The blocks provided acoustic comfort by including açaí fiber blankets, the walls were assembled using blocks and a commercial product for laying and overlapping. Housing as a model for recycling materials discarded in the environment will be able to generate proper disposal, providing income, increasing the life cycle of these materials, producing ecological products in civil construction and meeting at least four of the Organization's Sustainable Development Goals-SDGs of the United Nations.

Navegar

Navegando Teses em Engenharia de Recursos Naturais da Amazônia (Doutorado) - PRODERNA/ITEC por Linha de Pesquisa "MATERIAIS E PROCESSOS DE FABRICAÇÃO"