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Contribution: This article describes how a peer learning strategy called student-led tutorials (SLTs) can improve student performance in an electromagnetism course (EM). This study provides empirical evidence on how promoting student active participation in collaborative problem-solving activities improves performance rates. Background: In 2019, an EM bachelor course introduced SLTs as a strategy to improve the 40% passing rates. Before SLTs, students perceived this course as very hard, uninteresting, disengaging, and nonfundamental to their studies. Intended Outcomes: A participatory environment that promotes active learning can deepen understanding of EM through problem discussion and peer collaboration. Application Design: This study uses an action research approach to analyze teaching practices and students performance. Based on this analysis, SLT is implemented and the results are examined. Drawing on professors' research on engineering education, traditional practice hours were transformed into SLT hours. Passing rates before and after the intervention were compared and correlated with SLT participation. In-depth qualitative interviews with students were conducted to understand how SLT related to their learning process. Findings: Since the intervention, the course passing rates increased 20%. More importantly, the grade distribution changed from a steep double exponential shape to a normal curve suggesting more students are doing better. There is a positive correlation between SLT participation and student performance. Students highly valued SLTs as a teaching strategy because it allowed discussion, enabled keeping up with the course pace, and created a culture of collaboration. Students also valued the mandatory aspect of SLTs, though they mentioned it increased the course workload.

In this work, ceramic monoliths were coated with powders based on exchanged Cs and/or Co cations in Na-mordenite (MOR) zeolite. SEM images showed that zeolite particles fill the macropores of cordierite walls and form a continuous layer of approximately 40 µm with good adherence. XPS analysis revealed that Co and Cs are present on the film surface solely as Co2+ and Cs+ at exchange positions in zeolite. The monolithic structures were evaluated for the butane-toluene co-adsorption and SCR of NOx with hydrocarbon mixture as the reducing agent. The presence of alkali metal cations in the zeolitic lattice favored the adsorption capacity of both hydrocarbons, while cobalt cations provoked a decrease in the adsorbed amounts due to its weak interaction with the HCs. Breakthrough curves of butane adsorption showed a roll-up phenomenon, associated with a competitive adsorption effect generated from toluene presence. In the desorption process, it was observed that adsorbed toluene hindered the butane diffusion through mordenite channels, which released at higher temperatures (above 250 °C). Cs2CoM and Cs7CoM monoliths were more active than the CoM monolith for NO-SCR. The presence of Cs cations close to Co cations increased the hydrocarbons concentration around active sites at high temperatures, according to TPD results, promoting the reduction activity of NO. [ABSTRACT FROM AUTHOR]

Calculations of the geometries and energies of the alkaline mordenites (MOR) CsxNa1–xMOR (where x = 0, 0.25, 0.5, 0.75, and 1) with and without toluene are reported. Differential scanning calorimetry (DSC) experiments are also shown. First, a structural stabilization of a pure silica zeolite was performed. Then four structures with different positions of the sodium atoms of the MOR with a molar ratio Si/Al = 5 were evaluated. The most stable structure was used to sequentially exchange sodium for cesium. In all cases, atoms are free to move to reach a local minimum of total energy. Toluene is initially located in three different geometries and the energy optimization calculation relocates it properly. Adsorption situations were observed when the electrons from the toluene aromatic ring interact with the sodium or cesium present within the main channel. DSC measurements were made with different amounts of toluene incorporated in MOR without cesium and in another with 7% of cesium. This technique indicated that the incorporation of Cs improved the adsorption capacity of the zeolite. The overall theoretical results are in good agreement with experimental evidence and constitute a reliable basis to advance in the study of new functionalized materials. [ABSTRACT FROM AUTHOR]