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Hands-on, active learning in engineering courses fosters deeper understanding, collaboration, and social skills for students. This paper reports on the design, fabrication, and testing of a transparent miniaturized shell-and-tube heat exchanger module for engineering thermo-fluids classes. This module was also implemented for in-class heat exchanger instruction, where students (sample size, N = 75) conducted hands-on experiments following the instructions provided in the associated worksheet, participated in pre-tests and post-tests, analyzed the experimental data, and provided their feedback through motivational surveys. The performance test data obtained from the developed desktop heat exchanger module shows that the experimental heat transfer rates are in good agreement with theoretically predicted values calculated based on the standard correlations and assumptions. The pre-test and post-test assessments show that the use of this miniaturized shell-and-tube heat exchanger module in classroom instruction improves fundamental understanding of the heat exchange process and enhances student comprehension of complex phenomena of fluid flow patterns and heat transfer in the different parts of the heat exchanger. The motivational assessments demonstrate the module’s efficacy in elucidating the underlying heat transfer mechanisms and facilitating active engagement. The developed low-cost, handson heat exchanger can be used in undergraduate thermo-fluids engineering education for visualizing and better understanding of heat transfer principles, enhancing engagement of students, improving retention of fundamental concepts, and finally bridging the gap between theoretical abstractions and real-world applications. 

Abstract ALICE is a large experiment at the CERN Large Hadron Collider. Located 52 meters underground, its detectors are suitable to measure muons produced by cosmic-ray interactions in the atmosphere. In this paper, the studies of the cosmic muons registered by ALICE during Run 2 (2015–2018) are described.The analysis is limited to multimuon events defined as events with more than four detected muons (N_μ> 4) and in the zenith angle range 0° < θ < 50°. The results are compared with Monte Carlo simulations using three of the main hadronic interaction models describing the air shower development in the atmosphere: QGSJET-II-04, EPOS-LHC, and SIBYLL 2.3d.The interval of the primary cosmic-ray energy involved in the measuredmuon multiplicity distribution is about4 × 10¹⁵<E_prim< 6 × 10¹⁶eV.In this interval none of the three models is able to describe precisely the trend of the composition of cosmic rays as the energy increases. However,QGSJET-II-04 is found to be the only model capable of reproducing reasonably well the muon multiplicity distribution, assuming a heavy composition of the primary cosmic raysover the whole energy range, while SIBYLL 2.3d and EPOS-LHC underpredict thenumber of muons in a large interval of multiplicity by more than 20% and 30%, respectively.The rate of high muon multiplicity events (N_μ> 100) obtainedwith QGSJET-II-04 and SIBYLL 2.3d is compatible with the data, while EPOS-LHC produces a significantly lower rate (55% of the measured rate). For both QGSJET-II-04 and SIBYLL 2.3d, the rate is close to the data when the composition is assumed to be dominated by heavy elements, an outcome compatible with the average energy E_prim∼ 10¹⁷eV of these events.This result places significant constraints on more exotic production mechanisms.