https://repositorio.unifei.edu.br/jspui/handle/123456789/481 2026-04-15T16:55:52Z 2026-04-15T16:55:52Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4323 2025-12-03T11:28:42Z 2025-07-02T00:00:00Z

Título: Análise e implementação de um algoritmo de sensação de movimento em uma plataforma de 2 graus de liberdade para treinamento de operadores de caminhões fora de estrada Abstract: Vehicle simulators in mining environments play an increasingly vital role in the development and training of operators, offering high safety, reliability, low cost, and the ability to create scenarios that would be difficult to reproduce under real conditions. However, due to spatial constraints, simulators cannot fully replicate the movements of real vehicles, especially off-highway trucks like the CAT793F, which exhibit distinct behaviors in acceleration, braking, turning, and other maneuvers. This work presents a methodology for implementing a washout-type Motion Cueing Algorithm (MCA) on a motion platform with two degrees of freedom (DoF), designed to simulate pitch and roll movements consistent with the operating conditions of mining trucks. The proposed algorithm was compared with an alternative approach and showed promising results, with better motion representation, lower response delay, and reduced system-induced noise. The evaluation of the results was conducted in three main stages: initially through an objective analysis using the OMCT (Objective Motion Cueing Test), followed by a comparison with the expected response of the human vestibular system, highlighting a good similarity, especially in the semicircular canals. Finally, the influences of noise and disturbances observed in the platform’s response were considered, with these deviations being strongly associated with dynamic effects resulting from the lack of anchoring of the base to the ground. This condition favors undesired displacements and imbalances during motion, directly affecting the accuracy of the simulation and the stability of the system. Tipo: Dissertação

2025-07-02T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4319 2025-11-10T13:00:19Z 2025-02-20T00:00:00Z

Título: Análise das fases cristalinas na soldagem GTAW de aço inoxidável AISI 316L revestido por Níquel-Watts utilizando Thermo-Calc Abstract: This study investigates the microstructure and mechanical properties of the austenitic stainless steel AISI 316L after performing GTAW (TIG) welding using commercially pure argon gas (with 2% oxygen) at the ends of sheets that were previously subjected to nickel electrodeposition, containing a nickel-Watts solution enriched with niobium particulate (with a particle size of less than 150 µm) at room temperature. To evaluate the mechanical properties and microstructural changes, tensile tests, potentiodynamic polarization, Vickers microhardness, ferritoscopy, and microstructural analyses were conducted. The welding resulted in the formation of austenitic and delta ferrite (δ) phases, with a pronounced concentration in the molten zone (MZ), attributed to the rapid cooling characteristic of the welding process. Additionally, the emergence of metallic carbides and sigma (σ) phase was observed at grain boundaries, particularly in the heat-affected zone (HAZ). Ferritoscopy revealed a significant increase in the volumetric fraction of ferromagnetic phases in the welded regions, reaching 6.7% Fe in the MZ, 3.3% Fe in the HAZ, and 0.5% Fe in the base metal (BM). The microhardness results demonstrated differences among the analyzed regions, with the ZF exhibiting the highest microhardness value (231 HV ± 7 HV), followed by the ZTA with an intermediate value (188 HV ± 6 HV), and the base metal (BM) showing the lowest value (174 HV ± 1 HV). In the potentiodynamic polarization tests, the results indicated minimal variations in corrosion and pitting potentials between the base metal and the welded samples. For the welded sample, the average corrosion potential was measured at 0.02 V ± 0.01 V, with an average pitting potential of 0.24 V ± 0.01 V. Conversely, the base metal exhibited an average corrosion potential of 0.05 V ± 0.01 V and an average pitting potential of 0.29 V ± 0.01 V. Microfractographic analyses characterized the fracture of the welded samples as ductile, with the presence of dimples indicating a good capacity for deformation prior to rupture. Despite the addition of niobium to the nickel-Watts solution, the formation of niobium precipitates in the material was not identified, which may be attributed to the low thickness of the coating compared to the thickness of the weld bead, resulting in insignificant improvements in mechanical properties and corrosion resistance. Tipo: Dissertação

2025-02-20T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4229 2025-05-06T14:11:14Z 2024-11-23T00:00:00Z

Título: Evolução dos instrumentos de gestão dos recursos hídricos em Minas Gerais: estudo de caso das bacias hidrográficas dos Rios Paracatu e Piracicaba Abstract: In Brazil, concern about water management is clearly seen in the state of Minas Gerais, with strong action by the water resources management body, the Minas Gerais Institute for Water Management (IGAM), together with the National Water and Basic Sanitation Agency (ANA), the River Basin Committees (CBHs) and other local authorities. Water management in the state relies on the use of the five management instruments set out in the so-called Water Law: water resources plans; classification of water bodies into classes; granting of rights of use; charging for the use of water resources; and an information system. In this context, this work assesses the implementation and evolution of these instruments in Minas Gerais, with an emphasis on the Paracatu (a tributary of the São Francisco River) and Piracicaba (a tributary of the Doce River) river basins, which play an important role in the state's economy, with agricultural and mining activities predominating, respectively. The work methodology included consultations to understand not only the process of implementation and evolution of the management instruments, but also the characterisation of the study areas in terms of physiographic, economic and other aspects, in order to find out how these factors can influence the water availability of the basins. Thus, the results obtained show the history of the implementation of the instruments in the basins studied and allow us to identify the main challenges already faced, among them the lack of updating and monitoring of the fulfilment of the targets set in the water resources plans and the difficulty in managing grants, which has led to water shortages in some regions. The results make it possible to identify the gains from implementing the charging instrument, so that the amounts collected help to protect the river basin, preserve springs and watercourses, as well as enabling the financial execution of various projects. Thus, the results obtained in this study allow us to conclude that the mere implementation of these instruments is insufficient, and that assertive management is needed that takes into account the specificities of each river basin. Tipo: Dissertação

2024-11-23T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4228 2025-05-05T16:55:22Z 2024-11-21T00:00:00Z

Título: Uso da modelagem de qualidade da água na gestão dos recursos hídricos aplicada à bacia do Rio Santa Bárbara-MG Abstract: Mathematical modeling of water quality is essential for evaluating the impact of pollutant discharges on water bodies. It enables the assessment of intervention scenarios, the implementation of control measures, the verification and quantification of self-purification processes in water bodies, and the simulation of current and future water quality scenarios in rivers. The main objective of this research was to conduct water quality modeling of the Santa Bárbara River to support water resources management. For the mathematical modeling, the parameters dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrogen variations (organic, ammoniacal, nitrite, and nitrate), and phosphorus were modeled using the QUAL-UFMG model. Additionally, future scenarios were examined that accounted for population growth in the watershed, with projections for 2033. In Scenario 1, the urban centers of the municipalities of Barão de Cocais and Santa Bárbara were considered to have implemented sewage treatment for 90% of their populations, while in Scenario 2, all urban centers within the study area of the basin were considered to have implemented sewage treatment for 90% of their populations. In the current scenario, with the exception of phosphorus, all studied parameters remained within the limits established for Class 2 waters according to CONAMA Resolution 357/2005 for 100% of the studied section, with only 7.6% compliance for phosphorus. For Scenarios 1 and 2 in 2033, the analyzed parameters would remain within the established limits for Class 2 waters according to CONAMA Resolution 357/2005 along the entire study section for all parameters, except for phosphorus, which remained non-compliant in 92.4% of the studied water body. Thus, it was concluded that for improved water resources management in the Santa Bárbara River watershed, it is necessary not only to intensify effluent treatment and control pollution sources, considering sewage treatment efficiency and population size of the main cities within the watershed, but also to address diffuse pollution sources arising from land use and occupation (such as agricultural residues, soil erosion, and sediments) originating from its tributaries. Tipo: Dissertação

2024-11-21T00:00:00Z