https://repositorio.unifei.edu.br/jspui/handle/123456789/65 2026-04-29T07:43:03Z https://repositorio.unifei.edu.br/jspui/handle/123456789/3173 Aquisição e validação de sinal de ruído eletroquímico Corrosion is a global problem, which implies costs in industrialized countries of up to 4.5% of GDP, with either economic, but also social and environmental impacts. In the case of Brazil, the waste of water supply networks due to leaks loss is quite significant and much of it is caused by network degradation, indicating that corrosion control should be promoted whenever possible. This study proposes a corrosion monitoring system, in system subject to the use of inhibitor, with the approach of passive technique for monitoring corrosion by electrochemical noise (EN), in which the classification of events in a corrosion sensor by EN is part of methodological study for structural integrity (or “health”) monitoring system (SHM). Due to very dynamic and stochastic nature of the signal, this study and analysis of EN measurements (ENM) considers numerical and graphic characteristics of two corrosion systems both in saline aqueous solution: carbon steel and stainless steel. These experiments are repeated for accumulating data, which allow the generation of several graphs in time and frequency domains, from which at least one characteristic is extracted, which has a good correlation with data from corrosion processes. Then, based on a supervised machine learning system, the training data allows the model to be calibrated. From the test data, the correctness rate of the model above 50% is verified. Dissertação 2022-02-17T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4399 Mudanças climáticas e saúde mental: percepção e memória de pessoas idosas de Santa Rita do Sapucaí Population aging is a growing reality on a global scale and poses significant challenges to public policies, especially regarding the protection of mental health in later stages of life. Throughout aging, specific physical, emotional, and social conditions emerge that, in certain environmental contexts, influence coping mechanisms. Simultaneously, climate change is intensifying, with its impacts becoming more frequent and severe, disproportionately affecting territories marked by socio-environmental inequalities where older people construct their life trajectories and aging processes. In this context, this study aimed to understand how older people perceive and psychologically experience ongoing climate change, investigating its impacts on the mental health of the elderly population in the municipality of Santa Rita do Sapucaí, in southern Minas Gerais, a region characterized by the recurrence of extreme weather events, such as floods. It is based on the understanding that the intersection between population aging and climate change exacerbates vulnerability, demanding coordinated responses from different sectors of public policy. A qualitative approach was adopted, based on the Collective Subject Discourse method, using interviews conducted with elderly residents of the municipality. The analysis of the discourses allowed for the identification of emerging categories that express shared meanings, emotions, and interpretations about the climate phenomenon. The results indicate that climate change is perceived as a concrete and progressive process, associated with the loss of climate predictability, the recurring fear of new extreme events, and an increased feeling of insecurity and helplessness. Manifestations of psychological distress are observed, such as anxiety, constant worry, and fear, frequently anchored in previous experiences with floods and in the memory of a past climate perceived as more stable. These narratives reveal the formation of a collective climate memory, in which recollections of extreme events and past environmental transformations shape the current perception of risk and guide ways of coping with and giving meaning to suffering. Furthermore, the fragility of local public policies in the psychosocial care of the elderly population in contexts of climate risk is evident. It is concluded that climate change significantly impacts the mental health of the elderly population, articulating emotional, social, and symbolic dimensions of aging. The study highlights the need for public policies that integrate mental health, climate justice, and social protection, recognizing older people as central actors in the processes of adaptation to and coping with climate change, with strategies sensitive to territory, memory, and socio-environmental inequalities. Dissertação 2026-02-10T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4398 Efeito do método e da atmosfera de sinterização nas propriedades termoelétricas das cobaltitas de cálcio dopadas com bismuto Electrical power generation from the recovery (or conversion) of waste heat in thermal systems emerges as a sustainable alternative for mitigating the negative impacts of fossil fuel use. The energy conversion performance of thermoelectric materials is considered high when the material exhibits high values of figure of merit (zT > 1.0). Calcium cobaltite (Ca3Co4O9, CCO) stands out among oxides with potential thermoelectric application due to its chemical stability at high temperatures, high electrical conduction, and reduced thermal conduction. The material behaves as a p‑type semiconductor, conducting electricity mainly by electronic holes transported by a hopping mechanism, which migrate from Co4+ to Co3+. Its distinct crystal structure, composed of rock‑salt‑type layers (Ca2CoO32−) and CdI2‑type layers (CoO22+), gives the material morphological characteristics of lamellar particles. Although this complex structure brings benefits to the thermoelectric properties, the morphology of its particles makes it difficult to densify CCO ceramics, which is crucial for the ceramics to exhibit high thermoelectric performance. Additionally, doping with heavy chemical elements such as Bi3+ can induce distortion in the crystal lattice, decreasing the thermal conductivity of the material, as well as increasing the Seebeck coefficient. Thus, aiming to enhance the thermoelectric properties of CCO ceramics, this work combined the use of different sintering techniques and atmospheres. The compositions Ca3Co4O9 and Ca2.8Bi0.2Co4O9 were synthesized by the solid‑state reaction method using the precursors CaCO3, Co(NO3)2·6H2O, and Bi2O3. The ceramics were conventionally sintered in oxidizing atmospheres (air or O2) at 900 °C for 9 h or were sintered by the non‑conventional microwave (MW) technique at 900 °C, with a dwell time of 30 minutes. Alternatively, the MW‑sintered ceramics were subjected to subsequent heat treatments carried out in a conventional furnace, in O2 atmosphere, at 900 °C for 9 h, in order to reduce the concentration of oxygen vacancies and stabilize the CCO phase. X‑ray diffraction (XRD) analyses of the calcined powders revealed that the addition of Bi maximized the formation of the main phase (93.4(4)% of Ca3Co4O9) compared to the undoped composition (81.8(9)%). Scanning electron microscopy (SEM) micrographs showed that the doped ceramics presented larger grain size than those obtained for the undoped ceramics. The undoped samples achieved higher densification (relative geometric densities between about 66.4±0.2% and 69.3±0.7%) and lower apparent porosity (34.7±0.2% to 36.2±0.3%) compared to the doped ceramics, with MW sintering being the most efficient to densify the undoped ceramics. Furthermore, the undoped ceramics presented Seebeck values higher than most doped ceramics. The only exception was the ceramic sintered by MW at 900 °C for 30 minutes, which reached the highest Seebeck value. The undoped samples conventionally sintered in air presented the best thermoelectric results, reaching a power factor of 0.22 mW/m·K² at 600 °C. Dissertação 2026-02-19T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4397 Orquestração de contêineres em computação de borda: uma avaliação de desempenho comparativa entre K3s e K0s The rising adoption of containers as a lightweight virtualization technology has paralleled the popularity of microservice architectures, given containers’ inherent scalability, isolation, and ephemeral nature. While container orchestration frameworks have traditionally been utilized in data centers, there is growing interest in deploying these frameworks on resource-constrained devices, such as Internet of Things (IoT) devices, edge gateways, and developer workstations. This shift is driven by the need for automated provisioning, deployment, scaling, networking, and load balancing across diverse environments. However, with a range of container orchestration solutions available, selecting the appropriate platform remains a challenge for developers. This paper presents a comparative analysis of container orchestration platforms, beginning with a literature reviewto examine various platforms and their applicability across different environments. Following this, K3s and KOs are selected for an in-depth evaluation under a specified scenario, focusing on their minimal resource requirements, as well as control plane. Through this approach, we identify key factors and optimal use cases, offering insights into the suitability of these platforms for resource-constrained hardware environments. Dissertação 2025-12-19T00:00:00Z