http://repositorio.ufc.br/handle/riufc/509 Tue, 07 Apr 2026 19:04:24 GMT 2026-04-07T19:04:24Z http://repositorio.ufc.br/handle/riufc/84215 Título: Análise de desempenho e emissões de simulações de caminhões híbridos elétricos com autonomia extendida (REEV) Autor(es): Uchoa Filho, Francisco Elmo Lima Abstract: The worsening global climate crisis demands urgent strategies to mitigate environmental impacts in a wide range of human activities. The transport sector is responsible for around 23% of all global CO 2 emissions, and of this total, 29.4% comes from trucks. On the other hand, little research has been conducted on this transport mode. Given the global trend toward the adoption of electric trucks, the strategies adopted in many countries are evaluated. Brazil’s history with biofuels, especially ethanol, indicates that range extended electric vehicles (REEV) are the ideal solution for the country. This work proposes a study of the performance of different truck configurations with power trains (the set of components responsible for propelling the vehicle) in the REEV configuration. Four truck models are proposed, two with a maximum load of 23t and two with 57t, three power levels for the ethanol-powered combustion engine, combined with up to 17 different groups of battery banks in parallel. Thus, one-dimensional powertrain models are developed on the Realis Ignite platform based on commercial components and vehicles. Aided by routines developed in Python, the various powertrain configurations are simulated in successive standardized driving cycles. The combinations with the lowest specific energy consumption are selected, being the minimum 0.633MJ/t.km. The emissions of CO 2 , NO x , CO, and HC were evaluated according to national standards, equivalent to Euro VI, with all simulations being in compliance. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/84215 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/83444 Título: Síntese e caracterização de óxido de grafeno reduzido preparado a partir de grafite natural via método hummers modificado Autor(es): Freitas, Nichollas Rodrigues Bezerra Tipo: Dissertação Mon, 01 Jan 2024 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/83444 2024-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/82707 Título: Análise da resistência e do desempenho de membranas de troca protônica (PEM) à base de quitosana sob variação de temperatura Autor(es): Braga, Marcelo Rocha Abstract: This work investigates the fabrication and performance of chitosan-based membranes for hydrogen PEM fuel cells. The search for renewable energy sources has been increasing steadily in recent times, with a growing interest in hydrogen-based energy generation mechanisms, among which the so-called PEM (Polymer Electrolyte Membrane) fuel cells stand out. These cells, through a polymeric membrane, allow the migration of hydrogen protons from the anode to the cathode, where they combine with oxygen, generating energy and water as products. Various materials can be used for the fabrication of this membrane; in this study, the focus was placed on developing an organic membrane based on chitosan, doped with different reagents. Performance and resistance tests were conducted under increasing temperatures to evaluate the viability of this low-cost organic compound for the market. The methodology involved dissolving chitosan and polyvinyl alcohol (PVA) mixtures in a solution of sulfosuccinic acid (SSA) and hydrochloric acid, followed by drying and treatment with sulfuric acid. The resulting membranes were then used in a fuel cell for testing. The test results showed that the doped membranes exhibited good structural stability and efficient energy generation at room temperature, with voltages comparable to commercial materials such as Nafion®. During the temperature tests, distinct behaviors were observed between the membranes with and without additional sulfuric acid doping, suggesting improved thermal stability in the presence of H₂SO₄. However, overall performance remained relatively low, with functionality maintained only up to approximately 150 °C, although with potential for improvement through better system humidification. The characteristics observed suggest that chitosan membranes can be viable and sustainable alternatives for hydrogen fuel cells and may achieve even better results with further additives and modifications to enhance their thermal resistance and proton conductivity. This could contribute significantly to the energy transition using organic and renewable materials. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/82707 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/82705 Título: Análise integrada de melhoria em um protótipo de drone multirotor solar: simulações CFD, caracterização de encapsulantes e testes de potência Autor(es): Menezes, Caio Ramos de Abstract: In recent decades, to address the environmental crisis caused by human use of fossil energy, solar energy has been considered one of the possible alternative energy sources. Photovoltaic solar cells are being used in a variety of applications, from powering watches and calculators to charging batteries for boats. One of the areas of interest for researchers is alternative energies associated with drones, whether for mapping solar farms, monitoring wind farms, or designing prototypes using solar cells. The objective of this work is to apply innovations and improvements to a hybrid solar multirotor drone as a continuation of the research conducted by two graduates from the Graduate Program in Mechanical Engineering at the Federal University of Ceará (PPGEM-UFC). The study began with a bibliometric analysis related to drones powered by or utilizing solar energy. For this analysis, documents were selected from the Scopus and Web of Science databases, and duplicates were unified and removed from the data, resulting in 404 documents. From the analysis, it was observed that China is the country with the most publications, accounting for around 40%. The four institutions that produced the most on this topic are all based in China, representing about 46% of the listed publications. To achieve these objectives, an aerodynamic study was developed through fluid dynamics simulations of the three prototypes built by (VELANDIA, 2018), using Ansys Fluent software with the SST K-ω turbulence model. The results showed a large turbulence region at the rear and negative lift coefficients in all three prototypes, factors responsible for the poor aerodynamic performance of the models. Another proposed study involved evaluating the mass, electrical power, and mechanical resistance of acrylic encapsulants in solar cells through analyses using a digital scale, conventional multimeter, and a universal tensile testing machine. The results indicated that PETG sheets are a potential solution for improving mechanical resistance, with an increase in mass, although this increase is smaller compared to 2 mm acrylic sheets. To assess the potential power of the four motor/propeller assemblies and verify the maximum load capacity associated with the drone, a test bench was created using 3D printing, and the motor connection circuit was assembled. The maximum thrust capacity of the four motors was 1145.5g with a 2S battery and 2311g with a 3S battery. Therefore, a 3S battery is better suited for the project. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/82705 2025-01-01T00:00:00Z