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)
Análise de vibrações mecânicas em estruturas esbeltas e flexíveis, como cordas e vigas, sujeitas à movimentação axial utilizando a técnica da transformada integral generalizada
(Universidade Federal do Pará, 2024-05-28) PORFÍRIO, Rogilson Nazaré da Silva; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505; QUARESMA, João Nazareno Nonato; http://lattes.cnpq.br/7826389991864785; https://orcid.org/0000-0001-9365-7498
The dynamic analysis of vibrations on flexible structures is of an extreme importance in engineering and its solution represents a significant challenge to be tackled. This study has the objective to investigate thin and flexible structures such as beams and ropes, that oscillate in supports clamped-clamped and clamped-concentrated mass, which determine the boundary conditions of the analysis problem. Using the generalized integral transformation technique (GITT) that converts the partial differential equation (PDE) developed by the Hamiltonian method in an Ordinary Differential Equation (ODE), it optimizes the numerical process andcontrols efficiently the relative error of the calculations. In this study, it was developed and applied an innovative method that treats the boundary conditions without the use of filters to homogenize the equations. The calculations methodology was implemented in Fortran, utilizing a sub-routine DIVPAG of IMSL. As reference, a thorough analysis of convergence and stableness was applied, considering the behavior of four different models of ropes and two models of beams. The validation of methodology was approached comparing functional aspects such as transversal displacement, system velocities, frequencies, and damping, with results obtained by GITT and other studies that applied the same simulation conditions. The results of this study were found to be satisfactory, which highlights the relevancy of application of this vibration analysis method. It was also assessed the application of this method in different vibration configurations in each model, which exemplifies its broad potential in problems involving the structures analyzed. Therefore, this study represents a significant contribution to the advance of knowledge in dynamic modeling of thin and flexible structures and highlights the influence of boundary conditions in vibrational characteristics of these structures.Furthermore, it introduces an innovative methodology for treating boundary conditions without the use of filters, expanding the analysis possibilities in this field of engineering.
Acesso aberto (Open Access)
Análise energética, exergética e tecnoeconômica de um sistema de condicionamento de ar baseado na regulação natural da energia solar em condições climáticas da Amazônia
(Universidade Federal do Pará, 2023-09-01) SANTOS, Elson Costa dos; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088
This work investigates the behavior of a photovoltaic air conditioning system, without batteries or connection to the electrical grid, operating according to the natural regulation of solar energy, in climatic conditions in the Amazon, a region with significant energy challenges, where in many locations, children, adolescents, adults and the elderly live without one of the main inputs for the development of productive, educational, leisure and even subsistence activities. The simulation results indicate that a system powered by a 1400 Wp photovoltaic generator can maintain thermal comfort conditions, with temperatures between 20 °C and 26 °C and relative humidity between 40% and 80%, for almost half of the operating time. and without any active control. Exergy analyses reveal variations in efficiency and irreversibility of components throughout the day, with the greatest impact on the photovoltaic system, followed by the compressor, condenser, evaporator, and expansion valve. Furthermore, the economic analysis shows that the implementation of these systems in parallel to systems powered by the conventional electrical grid can reduce grid energy consumption by 60.76%, and is strongly related to the tariff charged by the energy concessionaire. Finally, the research demonstrates the use of photovoltaic air conditioning systems as a sustainable solution for cooling, showing its effectiveness with the natural regulation of solar energy and its economic contribution to reducing the consumption of non-renewable energy
Acesso aberto (Open Access)
Estudo da incorporação de resíduos industriais, lama vermelha e caulim, nas propriedades de compósitos de matriz poliéster reforçados com fibras de juta e malva
(Universidade Federal do Pará, 2022-07-18) RIBEIRO, Maurício Maia; SILVA, Alisson Clay Rios da; http://lattes.cnpq.br/7389345867032737; https://orcid.org/0000-0001-9186-2287; CANDIDO, Verônica Scarpini; http://lattes.cnpq.br/8274665115727809; https://orcid.org/0000-0002-3926-0403
The Amazon region of Brazil is a major producer of bauxite and kaolin, with the state of Pará accounting for a large national share of the production of these materials. The processing of these raw materials generates considerable amounts of waste that is then stored in sedimentation ponds which can cause serious environmental damage, therefore it is very important to explore reasonable methods of utilizing the red mud and kaolin waste, and thus reduce their landfill volumes. Many recent studies have been conducted and presented various ways of comprehensive utilization of these wastes. Natural fiber reinforced composites with insertion of these industrial wastes have received increasing attention in recent decades, as good specific mechanical properties can be achieved and industrial wastes can be reduced and used in a useful form. In this work, polyester matrix composite materials reinforced by jute and mallow fibers in continuous configuration and aligned at 0° and 90° in the loading direction, and composite materials with insertion of industrial waste were manufactured. The polyester matrix used was a pre-accelerated orthophytalic and cured at room temperature with methyl ethyl ketone peroxide 1.0% by mass. The Jute and mallow fibers were manually cut in length of 300 mm and manually arranged in a continuous manner and aligned and without surface treatment. Fiber composites were produced by vacuum-assisted hand lay-up/vaccum-bagging procedure. The proportions of the fiber volume fraction have varied by 5, 15 e 25 %. The composites with kaolin and red mud residues were manufactured by a manual process in the form of silicone and pressed mold. The proportions of the mass fractions of waste have varied by 5, 10, 15, 20, 25 e 30 %. The residues were characterized in terms of their physical, morphological and chemical aspects and the fibers in terms of their physical and mechanical aspects and the experimental values are similar to that presented from old newspaper. Just as the composites manufactured had their specific mass determined, which resulted in an increase in the average value of the specific mass of the composites with insertion of red mud and kaolin residues. In the case of composites reinforced with fibers of jute and mallow, there was a reduction in the average value when compared to the matrix. Tensile and shear properties were observed for the composites with industrial waste, red mud and kaolin. The composite 5RC exhibited tensile strength value closer to the matrix, as well as for 5RLV, 10RLV and 15 RLV which exhibited the same behavior. For shear strength the composites 10RLV and 15 RLV were closer to the matrix. As well as the composites reinforced with jute fibers 0° presented the highest tensile strength were 0J5, 0J15 and 0J25, exceeding in 2%, 150% and 166% the tensile strength of polyester. For the composites reinforced with mallow fibers 0° showed the highest tensile strength were 0M15 and 0M25, exceeding in 67% and 96% the tensile strength of polyester. For shear strength the composites reinforced with jute (0J15 and 0J25) and mallow (0M15 and 0M25) fibers exceeded the matrix in 201%, 206%, 71% and 144%, respectively. The tensile strength of the three-phase composites (0JRLV, 0JRC, 0MRLV and 0MRC) exceeded the matrix by 129|%, 100%, 54% and 21%, respectively. For shear strength they exceeded the matrix by 49%, 47%, 63% and 52%. Composites with 0-aligned fibers showed satisfactory mechanical behavior for application in composite materials presenting reinforcement characteristics.
Acesso aberto (Open Access)
Interações de ftalocianinas de Co, Cu e não metálicas com estruturas externas de SARS-CoV-2 utilizando docking e dinâmica molecular
(Universidade Federal do Pará, 2021-12-22) ALENCAR, Wilson Luna Machado; CHAVES NETO, Antonio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512

Navegar

Navegando Teses em Engenharia de Recursos Naturais da Amazônia (Doutorado) - PRODERNA/ITEC por Afiliação "IFPA - Instituto Federal de Educação, Ciência e Tecnologia do Pará"