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Computational tool to evaluate the efficency of hydrogen in internal combustion engines
(Universidade Federal de Lavras, 2025-03-20) Rincon, Alvaro Ferney Algarra; Alvarez, Carlos Eduardo Castilla; Ensinas, Adriano Viana; Rodriguez, Christian Jeremi Coronado
Behavioral studies on the efficiency of a hydrogen engine are important, as they are part of a global initiative to decarbonize the automotive sector, and this technological route for the use of hydrogen is promising within recent energy transition studies. In this sense, the exploration of new technological development routes around production, commercialization and use of hydrogen for the state of Minas Gerais and for Brazil has been proposed through various government initiatives in recent years. For this reason, this work has developed a computational tool based on a zero-dimensional mathematical model capable of predicting the efficiency of a spark ignition engine when using hydrogen as fuel. The simplicity of the model offers a quick view of the operation and thermodynamics of the engine, which reduces computational effort and produces results that represent the real behavior of hydrogen combustion. This focus helps in the study of combustion and in making decisions about the economic viability of using hydrogen in internal combustion engines. To do this, the compression, combustion and expansion processes in the Otto cycle were mathematically modeled to represent the combustion behavior of the air-hydrogen blend inside the engine cylinder, using code written in MATLAB. The mathematical model was validated with experimental data taken from the research engine bench and those reported in the literature in relation to the pressure curve for the different engines and operating conditions evaluated, and the efficiency produced by the engine under these conditions was estimated. A graphical interface was generated in AppDesigner for the computational tool, making it easier for the user to develop the behavioral and operational study of a hydrogen engine. The results obtained with the computational tool show that the estimated pressure and efficiency values are in good agreement with those found in the literature in all the cases evaluated. The maximum error when comparing the pressure curve was 1.32% for an engine with a speed of 3300 RPM. In addition, the minimum fit of the mathematical model to the experimental data was 86%, which represents a good alternative for estimating the thermal efficiency value.
Impactos das mudanças climáticas e do uso e cobertura do solo na disponibilidade hídrica da bacia do rio Paraopeba
(Universidade Federal de Lavras, 2026-02-03) Souza, Patrick Gustavo Machado; Alvarenga, Lívia Alves; Tomasella, Javier; Mello, Carlos Rogério de; Melo, Pâmela Aparecida
The Paraopeba River basin, located in the state of Minas Gerais, Brazil, is strategic for public water supply, irrigation, and economic activities in the Metropolitan Region of Belo Horizonte. In recent years, the basin has undergone intense environmental changes resulting from climate change and significant transformations in land use and land cover, including deforestation, urban expansion, mining, and agricultural activities. In a context of water vulnerability, this study analyzed and quantified the impacts of climate change and anthropogenic activities on water availability in five sub-basins of the Paraopeba River Basin between 1986 and 2022. To this end, the Budyko curve decomposition method was adopted. This method, based on the relationship between precipitation, potential evapotranspiration, and actual evapotranspiration, allowed the decomposition of relative contributions from climate, through the aridity index, and from land use and land cover changes. The results showed an increasing trend in aridity in the region since 2014. All five analyzed sub-basins exhibited reductions in runoff, to varying magnitudes, due to both climatic and anthropogenic influences up to the end of 2022, with the most pronounced reduction observed in Sub-basin 5, reaching 57.31% relative to the mean runoff. In Sub-basins 2, 3, and 4, the negative effects of climate on runoff were partially offset by the opposing influence of anthropogenic activities; however, these effects were not sufficient to result in a positive total runoff balance. Sub-basin 5, corresponding to the most downstream accumulated area, presented the most critical scenario. In addition to climatic effects, land use also contributed to runoff reduction, indicating that extensive agricultural land use, marked by a strong presence of temporary crops, along with intensified water withdrawals especially for irrigation—may have played a significant role in reducing runoff. The results demonstrate that climate change and anthropogenic activities significantly affect water availability in the Paraopeba River Basin and may increase local vulnerability to drought events, which have become more frequent, severe, and intense in the basin.
Síntese, caracterização e avaliação da atividade antimicrobiana de derivados 4h-cromen-5-onas
(Universidade Federal de Lavras, 2026-02-04) Alexandre, Kamilla Vitar; Thomasi, Sérgio Scherrer; Pieve, Adrielle; Bellete, Bárbara Sayuri
Antimicrobial resistance (AMR) constitutes one of the major current threats to public health, reducing the effectiveness of widely used antimicrobial agents and requiring the development of new therapeutic approaches. In this context, heterocyclic compounds derived from chromenones, have attracted considerable interest in medicinal chemistry due to their structural diversity and the biological potential reported in the literature. The present study aimed to synthesize, structurally characterize, and evaluate the antimicrobial activity of six 4H-chromen5-one derivatives, obtained through multicomponent reactions (MCRs) aligned with the principles of Green Chemistry. The syntheses were carried out using a one-step, catalyst-free methodology involving substituted aromatic aldehydes, cyclic β-dicarbonyl compounds (dimedone or 1,3-cyclohexanedione), and the reagent (E)-N-methyl-1-(methylthio)-2- nitroethenamine (NMSM), resulting in functionalized 4H-chromen-5-one derivatives with satisfactory yields ranging from 75.4% to 84.75% and high synthetic efficiency. The synthesized compounds, designated KA, KB, KC, KD, KE, and KF, were characterized by Nuclear Magnetic Resonance spectroscopy (¹H, ¹³C, and ¹⁹F NMR) and infrared spectroscopy (FTIR-ATR), allowing the unequivocal confirmation of the proposed chemical structures and the assessment of their physicochemical properties. Antimicrobial activity was evaluated by determining the Minimum Inhibitory Concentration (MIC) using the broth microdilution method, in accordance with the guidelines of the Clinical and Laboratory Standards Institute (CLSI), against the bacteria Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. The assays were performed over a concentration range of 0.5 to 256 µg/mL, and MIC values higher than 128 µg/mL were observed for all evaluated derivatives, indicating the absence of significant antimicrobial activity under the tested conditions. Nevertheless, the structural features of the compounds suggest potential for topical applications and for future structural optimization studies. Additionally, the use of multicomponent reactions proved to be an efficient, sustainable, and reproducible synthetic strategy, contributing to the rational generation of molecular libraries and providing a foundation for future investigations into structural optimization and alternative therapeutic applications.
As políticas educacionais de inclusão na prática da Educação Física escolar e as perspectivas da valorização e/ou marginalização das diferenças
(Universidade Federal de Lavras, 2026-03-25) Anunciação, Julyê Aparecida dos Santos; Vieira, Rubens Antonio Gurgel; Ribeiro, Letícia Mendonça Lopes; Morais, Milena Pedro de
The concern that drives this research leads to an analysis of the Political-Pedagogical Project (PPP) of the schools investigated, a guiding document of an educational institution’s pedagogical practice, collectively and democratically conceived, which makes explicit the school’s identity, its principles, objectives, and goals, as well as the methodological and organizational strategies that enable the teaching–learning process grounded in equity. The general objective of the study is to analyze how inclusive educational policies are understood and applied in Physical Education classes in three state public schools located in the Northwest region of Belo Horizonte, identifying their effects on the valorization or marginalization of differences. The specific objectives include: (1) examining the Political-Pedagogical Projects (PPPs) of the schools investigated, verifying how they incorporate principles of equity and inclusion within the Physical Education curricular component; (2) analyzing Physical Education teachers’ understandings and practices regarding school inclusion, with attention to the pedagogical strategies, accessibility measures, and curricular adaptations adopted; and (3) identifying the main advances, challenges, and tensions present in the implementation of inclusion policies in Physical Education classes, relating them to the dynamics of valorization or marginalization of differences in everyday school life. Thus, the study is characterized as basic research with a qualitative and exploratory approach, employing procedures oriented toward case studies. The theoretical framework draws primarily, in the field of inclusion, on the works of Maria Teresa Égler Mantoan and Pedro Angelo Pagni; in curriculum studies, on the contributions of Tomaz Tadeu da Silva and Alfredo Veiga-Neto; in discussions of curriculum policy, on the work of Stephen J. Ball; and, with regard to teacher education, on the studies of António Manuel Seixas Sampaio da Nóvoa. Data collection was carried out through the administration of a structured questionnaire via Google Forms, designed to capture specific perceptions and to deepen the experiences reported by the research participants. The methodological scope was defined based on the premise that all Physical Education teachers belonging to the teaching staff of the schools in which the research was conducted would participate. The responses obtained were systematized and analyzed in six analytical subsections, whose interpretation and discussion highlight the originality of this investigation by revealing dimensions that remain underexplored in the field of school Physical Education. The study’s findings not only broaden the theoretical-methodological understanding of teaching practices but also provide an articulated foundation for the proposal of an educational product as a form of social feedback from the research. In this regard, a professional development initiative focused on inclusion was carried out for Physical Education teachers in the municipal school system of Belo Horizonte. It is expected, therefore, that this research will make a substantive contribution to deepening academic discussions in the field, foster further investigations, and offer pedagogical strategies aligned with the principles of equity, inclusion, plurality, diversity, and the appreciation of life in its multiple expressions.
Aplicação estratificada do tratamento químico na manutenção da qualidade fisiológica de sementes de milho armazenadas
(Universidade Federal de Lavras, 2026-02-12) Fernandes, Kevin Augusto Chaves; Carvalho, Everson Reis; Santos, Heloisa Oliveira dos; Silva-Mann, Renata
The increasing adoption of industrial seed treatment and the need to anticipate this process for logistical reasons have extended the storage period of treated seeds. Maize seeds may be produced by the seed industry in the first season of an agricultural year and sown in the field, for grain production, in the second season of the following year. Thus, they can be subjected to prolonged storage periods, which can reach up to approximately 360 days. However, the prolonged storage of treated seeds may cause a loss of physiological quality due to the long exposure of the seeds to chemical treatment components with phytotoxic potential, especially insecticides from the neonicotinoid group. Therefore, recent studies have explored alternatives to solve or mitigate this negative effect, such as the stratified application of the chemical treatment, which consists of applying the products sequentially rather than simultaneously, under the hypothesis that this separation reduces the contact of the seeds with potentially phytotoxic products. In this context, the objective of this study was to evaluate the effectiveness of the stratified application of chemical treatment in maintaining the physiological quality of maize seeds. The experiment was conducted in a completely randomized design in a 2 × 2 × 5 triple factorial scheme, comparing stratified and conventional applications (the latter with all products applied simultaneously), using two chemical treatment formulations with insecticides from different chemical groups, and evaluations performed over one year of storage. Seed physiological quality was assessed through germination tests, radicle length, accelerated aging on substrate, and cold test. It is concluded that stratified application constitutes an efficient technological alternative to extend the storability of treated maize seeds by presenting significantly higher vigor values with formulations of high phytotoxic potential and prolonged storage, contributing to greater safety in early treatment and the maintenance of seed vigor until sowing.