This paper studies the influence of metal precursors in the CVD´s catalyst synthesis of carbon nanotubes (CNTs) used as fillers in a polypropylene (PP) matrix (∼0.3 wt%). Two catalytic schemes, Fe/Al₂O₃ (50:50) and Ni–Fe/Al₂O₃ (40:10:50), were prepared to determine the influence of the reduction temperature over the characteristics and mechanical properties of CNT as PP fillers. The conversion temperature was varied to see the dependance of the CNT structure to this variable (700 °C–750 °C–800 °C). CNTs products were characterized by SEM and Raman spectroscopy. The SEM micrographs showed a sharper fiber type CNTs for the bimetallic catalyst and the Raman confirmed that better crystallites are obtain over the Fe catalyst. The Fe–PP composite presented enhanced mechanical properties when compare with Fe–Ni–PP, with tensile strength, hardness, and impact properties are higher in 16%, 9%, and 9% respectively. Other carbonaceous materials, as CNF, with less crystallinity presented poorer mechanical properties. Finally, can be stated that for the use of CNF as fillers in PP composites a Fe/Al₂O₃ catalyst, and a reaction temperature 700 °C–750 °C will produce a CNF with 60 nm mean diameter, is better than the use of Fe-Ni based catalysts.

Este estudio investiga la corrupción administrativa (CA) que sufrió alteraciones significativas en los últimos veinte años, pero los intereses existentes aún están lejos de ser atendidos. A partir del análisis de clúster para 253 artículos publicados (double review) se evidenciaron oportunidades y brechas en el trabajo de la ciencia que investiga la CA en el mundo. A partir de un análisis de contenido y de correspondencia, se comprobó que la violencia extrema, como el terrorismo y el narcotráfico, no se analizan en la agenda de la investigación de la CA; “crimen y punición” forman un enlace histórico en la teoría de la CA, pero raramente son investigados en el nivel del comportamiento humano y de Data Science; hay una incidencia significativa de publicaciones relacionadas con las prácticas de combate a la CA, mientras que los estudios que investigaron externalidades positivas y negativas para ese tema son escasos.

In this study, the plasmonic effect enabled by silver nanoparticles (AgNps) is evaluated for the enhancement of thermal performance in micro solar collectors. AgNps were synthesized via chemical reduction process using silver nitrate at varying concentrations (0.1, 0.2, 0,3, and 0.4 ml) and pH conditions (5.5–10.5). The creation of evenly spread nanoparticles with a size of 10–15 nm was confirmed by UV–vis spectroscopy and TEM analysis. The best results were seen when the pH was 10.5 and the concentration of silver nitrate was 0.2 ml (102 mg l⁻¹). Zeta potential measurements indicated good colloidal stability under these conditions. Thermal conductivity tests showed that nanofluids with AgNps enhanced the base fluid’s conductivity by up to 25% under simulated solar irradiation at 100% intensity. The plasmonic effect was evaluated in both homogeneous (AgNps are dispersed in a base fluid) and heterogeneous systems (AgNps immobilized on anionic resins). The observed maximum temperature difference of 1.4 °C was achieved at pH 10.5, silver concentration of 0.2 ml, and 2 suns irradiation. These findings highlight the potential of AgNp-based nanofluids to significantly enhance the solar energy harvesting systems, providing a promising avenue for advancing renewable energy technologies.

Objective: This study proposes the implementation of energy efficiency measures in the building of the Faculty of Science and Technology, as part of an extension project at the Federal University of Goiás. Theoretical Framework: The recommendations of the National Electricity Conservation Program (PROCEL) from the Energy Research Company (EPE) were the main guidelines used for the actions proposed in this study. Method: The current energy consumption was assessed through direct measurement, along with the projected energy demand and the analysis of electricity bills from December 2023 and August 2024. Additionally, the main issues related to the improper use of electricity were observed and discussed. Results and Discussion: Based on a review of the literature and, primarily, the recommendations of PROCEL-EPP, a banner was developed to compile the suggestions observed and discussed with project members, along with other visual elements. Thus, even in its initial stage, the actions proposed in this study show promise in contributing to the improvement of energy efficiency at FCT and, consequently, to sustainable development. Research Implications: The results of this research highlight the potential for reducing energy consumption through the implementation of energy efficiency measures in public buildings. Originality/Value: The present study demonstrates that it is possible to change people's habits and mitigate the problems of high energy consumption through the creation of campaigns promoting energy efficiency.

A preocupação global em reduzir os gases do efeito estufa e aumentar o uso de fontes renováveis levou o Brasil a se destacar como uma nação promissora nesse contexto, com grande parte de sua capacidade energética vinda de fontes renováveis. Porém, as fontes renováveis têm a desvantagem da intermitência e sazonalidade, o que levou à busca por soluções para esses desafios. Esse estudo avalia a viabilidade da integração hidro solar com um Sistema de Armazenamento de Energia Elétrica na Forma de Hidrogênio (SAEEH2) na usina hidrelétrica de Serra da Mesa. O hidrogênio seria produzido através da eletrólise da água, aproveitando o excesso de energia renovável disponível, e posteriormente convertido em eletricidade por meio de células a combustível. A integração hidro solar com o SAEEH2 proporcionou um aumento de 11,10% na energia produzida em comparação com a geração hidráulica convencional, sendo 36,06% provenientes do SAEEH2. Ademais, houve um aumento de 9,71% no uso da capacidade da subestação. Esses resultados destacam a viabilidade e os benefícios da integração hidro solar com o SAEEH2. Essa abordagem permite maximizar a geração de energia renovável, reduzir as emissões de gases poluentes e aproveitar melhor os recursos disponíveis, sem a necessidade de grandes investimentos em infraestrutura.