Students’ conception of set theory through a board game and an active-learning unit

We investigated whether two different learning interventions, Setarea board game and an active-learning unit, can promote the concepts of set theory in secondary students. Setarea was developed to help students learn set theory through the game’s components, mechanics, and missions. The game contained various decks of cards (collections), while its mechanics allowed players to perform different actions on the sets of cards (operations). The game’s missions required students to solve problems both individually and cooperatively. In the active-learning unit, a series of tasks related to set theory were provided. Students also cooperatively completed the provided tasks. The formal definitions and notations were introduced only in the active-learning unit. Seventh graders (have not learned), 9th graders (about to learn), and 11th graders (have learned) were recruited. For each grade, students were separated into two groups, engaging in the different learning interventions. We employed a pre-test–intervention–post-test design. In addition, we examined the students’ flow experiences which included three main dimensions: enjoyment, concentration, and control. A total of 183 Thai secondary students voluntarily participated in this study. The results revealed that both interventions significantly improved the students’ understanding, although no statistically significant differences between the two groups were found. Additionally, for each grade level, the students’ overall flow experiences from the board-game group were higher than those from the active-learning group, indicating that the board game was more immersive than the active-learning unit

Flow Regime Transition in Countercurrent Packed Column Monitored by ECT

Vertical packed columns are widely used in absorption, stripping and distillation processes. Flooding will occur in the vertical packed columns as a result of excessive liquid accumulation, which reduces mass transfer efficiency and causes a large pressure drop. Pressure drop measurements are typically used as the hydrodynamic parameter for predicting flooding. They are, however, only indicative of the occurrence of transition of the flow regime across the packed column. They offer limited spatial information to mass transfer packed column operators and designers. In this work, a new method using Electrical Capacitance Tomography (ECT) is implemented for the first time so that real-time flow regime monitoring at different vertical positions is achieved in a countercurrent packed bed column using ECT. Two normalisation methods are implemented to monitor the transition from pre-loading to flooding in a column of 200 mm diameter, 1200 mm height filled with plastic structured packing. Liquid distribution in the column can be qualitatively visualised via reconstructed ECT images. A flooding index is implemented to quantitatively indicate the progression of local flooding. In experiments, the degree of local flooding is quantified at various gas flow rates and locations of ECT sensor. ECT images were compared with pressure drop and visual observation. The experimental results demonstrate that ECT is capable of monitoring liquid distribution, identifying flow regime transitions and predicting local flooding.Comment: This is a draft paper of an article submitted to CEJ - Chemical Engineering Journa