https://repositorio.ufu.br/handle/123456789/18928 2026-06-16T15:55:49Z 2026-06-16T15:55:49Z https://repositorio.ufu.br/handle/123456789/48742 2026-06-09T06:20:29Z 2025-12-01T00:00:00Z

Title: Correlação estrutura-desempenho do ZnO na fotodegradação de poluentes e na redução eletroquímica de CO2 em CO Abstract: Anthropogenic activities generate excessive amounts of organic and inorganic pollutants, which are often released into water, air, and soil without adequate treatment. Heterogeneous photocatalysis has emerged as a promising approach for the photodegradation of organic contaminants, while electrocatalysis offers an efficient pathway for the electrochemical reduction of CO2. In this study, the effect of synthesis temperature and amine functionalization on the physicochemical properties and performance of zinc oxide (ZnO) was investigated in photo and electrocatalytic processes applied to:(i) the degradation of organic pollutants and (ii) the electrochemical reduction of CO2. The ZnO samples were tested for the photodegradation of pharmaceuticals (Amiloride and Ciprofloxacin) and dyes (Methylene Blue and Rhodamine B). The ZnO sample synthesized at 100 °C exhibited superior photocatalytic performance compared to those obtained at higher synthesis temperatures. This result can be attributed to the synergy between the Zn(OH)2/ZnO structural phases combined with the higher specific surface area of the material. (ii)The ZnO sample was modified with monoethanolamine, and its characterization revealed that the functionalization led to materials with distinct morphology and surface groups.The amino-functionalized sample, ZnO/Met-100, exhibited superior performance in the electrochemical reduction of CO2 to CO, achieving a Faradaic efficiency of approximately 90% for CO at current densities exceeding -100 mA cm-2.This result is attributed to the presence of amino groups on the ZnO surface, which enhance CO2 adsorption and increase selectivity toward CO formation. The in situ FTIR spectroscopy study enabled the monitoring of reaction intermediates and the proposal of a possible reaction mechanism. Electrochemical impedance spectroscopy (EIS) results confirmed that the presence of amino groups on the functionalized ZnO significantly reduced the charge-transfer resistance, thereby facilitating the kinetics of the electrocatalytic process. The stability of the amino-functionalized ZnO was investigated under electrochemical operating conditions, demonstrating excellent durability over 100 h of continuous operation in a membrane electrode assembly (MEA) cell. The system operated at a current density of 50 mA cm-2, maintaining a Faradaic efficiency above 70% and a total cell potential of approximately 2.7 V. These results reinforce the viability of the material for sustainable electrocatalytic applications.

2025-12-01T00:00:00Z https://repositorio.ufu.br/handle/123456789/48187 2026-02-05T06:25:23Z 2025-10-20T00:00:00Z

Title: Modelagem preditiva de produtividade agrícola a partir de fontes de dados espaciais (FLDAS) para a cultura da soja na Mesorregião Norte do estado do Mato Grosso Abstract: Forecasting agricultural productivity is a strategic challenge for production planning, rural credit, and public policy formulation. In Brazil, such forecasts have traditionally relied on meteorological data from conventional weather stations, which are limited by inconsistencies, low spatial coverage, and temporal gaps. This study proposes the development of a crop yield prediction model based on climate data obtained from multisatellite remote sensing, integrating information from FLDAS/NOAH (NASA/Giovanni) for the historical period from 1989 to 2022. Climate variables, processed in NetCDF format, were spatially extracted from municipal centroids and combined with official soybean yield records provided by IBGE/SIDRA. The method applied was based on machine learning through ensemble decision trees (gradient boosting), exploring 216 climate variables derived from energy balance, hydrological fluxes, radiation, and atmospheric parameters. The results achieved a coefficient of determination (R²) of 0.823, with consistent RMSE and MAE values, demonstrating the model’s strong ability to reproduce observed yield variability, even without including agronomic variables such as soil fertility and management practices. Variable importance analysis using SHAP values highlighted that hydrological balance and radiation components were decisive in predicting yield during critical phenological stages of soybean. The findings indicate that the model is robust and scalable, allowing validation for other crops and agricultural regions. In addition to providing reliable forecasts, the proposed approach expands the potential for agricultural monitoring in areas lacking conventional meteorological data, representing a valuable tool for farm management, public policy, rural credit, insurance, and logistics planning.

2025-10-20T00:00:00Z https://repositorio.ufu.br/handle/123456789/46868 2026-01-14T14:59:58Z 2025-08-01T00:00:00Z

Title: A regulamentação do biogás como instrumento de enfrentamento das mudanças climáticas Abstract: Biogas is a renewable energy source that has the potential to contribute to combating global warming, but for its development, a National Policy is needed to regulate several aspects, such as economic, environmental and social. Some Brazilian states already have state legislation regulating this energy source, but at the national level there is a lack of regulations, causing legal uncertainty for investors, which hinders the expansion of this sector. Therefore, a national plan for its structural growth is advisable, which requires knowledge, financing and cutting-edge technology. And, to this end, a robust law is needed to unite the country around this purpose. Therefore, we argue in favor of modern regulation for biogas in Brazil, through an instrument that acts effectively in the decarbonization of society's activities and simultaneously contributes to climate justice, allowing the most vulnerable to use this energy source. There is no other path for humanity and the planet other than to adopt new production and consumption habits, gradually abandoning fossil fuels. Thus, this research covered concepts such as global warming, climate change, and the national and international system of fundamental standards for reducing greenhouse gas emissions. In addition, it addressed the energy transition, biofuels, and biogas, and at the end presented a draft of a bill on this subject. With this purpose, the research developed is of an applied nature, using the deductive method of approach and analyzing the objectives in a descriptive and exploratory manner, with consultation of bibliographic sources, periodicals, and national and international legislative documents as subsidies for interpretations and reflections on the proposed theme. In the end, it is concluded that, in order to regulate biogas, it is inevitable to provide for its exploration, waste management, and production with provision for investments and subsidies, which is provided for in such a normative proposal. Furthermore, the draft presented at the end of this thesis suggests devices for a National Policy aimed at stabilizing the climate crisis experienced on the planet, helping Brazil to achieve its goals for reducing greenhouse gases.; El biogás es una fuente de energía renovable con el potencial de contribuir a la lucha contra el calentamiento global. Sin embargo, para su desarrollo, se requiere una Política Nacional que regule diversos aspectos, como los económicos, ambientales y sociales. Algunos estados brasileños ya cuentan con legislación estatal que regula esta fuente de energía, pero a nivel nacional existe una falta de regulación, lo que genera inseguridad jurídica para los inversores y dificulta la expansión de este sector. Por lo tanto, es recomendable un plan nacional para su crecimiento estructural, que requiere conocimiento, financiación y tecnología de vanguardia. Para ello, se necesita una ley sólida que coordine al país en torno a este propósito. Por lo tanto, abogamos por una regulación moderna del biogás en Brasil, mediante un instrumento que actúe eficazmente en la descarbonización de las actividades de la sociedad y, a la vez, contribuya a la justicia climática, permitiendo que los más vulnerables utilicen esta fuente de energía. No hay otro camino para la humanidad y el planeta que adoptar nuevos hábitos de producción y consumo, abandonando gradualmente los combustibles fósiles. Por ello, esta investigación abordó conceptos como el calentamiento global, el cambio climático y el sistema nacional e internacional de estándares fundamentales para la reducción de las emisiones de gases de efecto invernadero. Además, abordó la transición energética, los biocombustibles y el biogás, y finalmente presentó un borrador de proyecto de ley sobre este tema. Con este propósito, la investigación desarrollada es de naturaleza aplicada, utilizando el método deductivo de aproximación y analizando los objetivos de manera descriptiva y exploratoria, con consulta de fuentes bibliográficas, publicaciones periódicas y documentos legislativos nacionales e internacionales como subsidios para interpretaciones y reflexiones sobre el tema propuesto. Finalmente, se concluye que, para regular el biogás, es inevitable prever su exploración, gestión de residuos y producción con previsión de inversiones y subsidios, lo cual está previsto en dicha propuesta normativa. Además, el borrador presentado al final de esta tesis sugiere mecanismos para una Política Nacional destinada a estabilizar la crisis climática experimentada en el planeta, ayudando a Brasil a alcanzar sus objetivos de reducción de gases de efecto invernadero.

2025-08-01T00:00:00Z https://repositorio.ufu.br/handle/123456789/45410 2025-05-08T06:20:29Z 2024-12-06T00:00:00Z

Title: O contrato de trabalho de curtíssima duração como instrumento de salvaguarda de direitos sociais ao trabalhador rural de culturas agrícolas sazonais Abstract: This doctoral thesis aims to answer the question of the validity of very short-term employment contracts for rural work. The thesis sought to develop the validity of a specific type of employment contract -- of very short duration -- for rural workers. The research objectives were to describe and analyze this contract proposal based on its constitutional validity, fundamental social rights, and how it is adapted to the environmental policy and the biofuel energy matrix. The national sustainable energy matrix is also dependent on agricultural labor, and this contract proves to be convenient in the reality of rural production. The research is of a basic strategic nature, presenting a possible solution in the regulation of rural labor. As it seeks to describe the regulatory system of labor, and at the same time already present a regulatory solution, it has a descriptive and exploratory character. The approach of the work is qualitative, seeking to express, in the end, a positive assessment for the adoption of this contract. The results are the basic delimitation of what this contract would be and its validity in the national legal system. The research relied on bibliographic and documentary sources for its final writing.

2024-12-06T00:00:00Z