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Surface activation of Monel 400 alloy as novel electrode for hydrogen production: insights on electrocatalysis and electroactive surface area
(Universidade Federal de São Carlos, 2026-01-09) Freitas, Jhonys Machado; Sgarbi, Ricardo; Ruotolo, Luis Augusto Martins; https://lattes.cnpq.br/2068549631838036; https://lattes.cnpq.br/2388966785886132; https://lattes.cnpq.br/6167735734348703
This work investigates Monel 400 as a non-noble metal electrocatalyst for the hydrogen evolution reaction (HER) in alkaline media, focusing on performance enhancement through electrochemical dealloying. Controlled electrocorrosion at 0.20 V and 0.45 V for different durations produced Ni-rich porous surfaces with significantly increased electrochemically active surface area (ECSA). Among the tested conditions, dealloying at 0.45 V for 60 min delivered the best performance, with overpotentials of 240 mV at −10 mA cm−2 and 389 mV at −80 mA cm−2, a Tafel slope of 105 mV dec−1, and a 20-fold increase in ECSA relative to pristine Monel. SEM and EDS revealed the formation of a hierarchical Ni ligament network with partial Cu depletion, while EIS confirmed enhanced capacitive and transport properties. The catalyst also demonstrated stable operation for 72 h. These results highlight dealloyed Monel 400 as a robust, scalable, and efficient HER catalyst for alkaline water electrolysis.
Cônicas: uma forma interessante para abordar o tema no ensino médio
(Universidade Federal de São Carlos, 2026-01-09) Zambon, Raphael Carlini; Barros, Tomas Edson; https://lattes.cnpq.br/5442017085057925; https://lattes.cnpq.br/3916639528250159; Barros, Tomas Edson; De Morais Filho, Daniel Cordeiro; Caetano, Paulo Antonio Silvani; https://lattes.cnpq.br/5442017085057925; https://lattes.cnpq.br/0266444096441721; https://lattes.cnpq.br/0370219014539994
The present study examines the role of manipulatives and digital technologies—specifically mathematical modeling and the use of GeoGebra—in the teaching and learning of conic sections, a topic often overlooked by high school mathematics teachers and one in which many students encounter considerable difficulty. The research investigated whether these approaches enhanced students’ understanding and performance, employing a methodology centered on practical challenges and computer-lab activities. Grounded in constructivist theory, the work emphasizes the importance of active learner engagement with the environment as a catalyst for meaningful learning. The project was designed to lead students to discover the conic sections through hands-on modeling, subsequently deepening their knowledge via theoretical instruction and enriching it with detailed exploration using GeoGebra. Group work in the creation of physical models initiated the discovery process. The lessons were developed in response to students’ questions and misconceptions arising during model construction, as well as to meet the curricular requirements of high school mathematics. Through modeling, problem-solving, and technological interaction with the conic sections, students experienced the mathematical content in a distinctive, contextualized, and engaging way. Keywords: Conic sections, Geogebra, manipulative models.
“Eu visto preto por dentro e por fora”: interseccionalidades entre o rap oralizado e o rap sinalizado
(Universidade Federal de São Carlos, 2026-01-09) Barros, Kamilly Castanha; Vasconcelos, Stephanie Caroline Alves; https://lattes.cnpq.br/2163002687410761; https://orcid.org/0000-0001-7323-9440; https://lattes.cnpq.br/7408548722149692
This study investigates how spoken rap and signed rap converge historically and socially, taking musical experiences as a starting point for academic reflection. The research stems from the observation of the lack of debate within universities regarding art produced by Black bodies, as well as by Black Deaf bodies within rap, and seeks to understand how art becomes a space of re-existence, allowing Deaf and peripheral subjects to recognize themselves as producers of culture. Grounded in historical-dialectical materialism and an intersectional perspective, the study discusses how spoken rap and signed rap, despite their distinct structures, converge in their purposes of denunciation, resistance, and the affirmation of insurgent identities. These artistic expressions, shaped by race, class, gender, and disability, confront mechanisms of social exclusion sustained by racism and capitalism, while simultaneously breaking with Eurocentric narratives imposed by matrices of oppression. The research demonstrates that spoken rap and signed rap share not only a critique of systemic violence, but also a re-signification of the acronym RAP (rhythm and poetry) as a practice linked to social movements and strategies of aquilombamento. Thus, it is concluded that both artistic forms make it possible to retell invisibilized histories, re-signify identities, and produce new forms of collective resistance.