This study presents a computational fluid dynamics analysis of dual‐layer phase change material (PCM) roofs for passive cooling in residential buildings under the hot and humid climate of Bangladesh. A three‐dimensional transient model was developed in ANSYS Fluent using the enthalpy–porosity approach to simulate coupled heat conduction, natural convection, and phase change under realistic boundary conditions. Rubitherm RT‐31, with a latent heat of 165 kJ/kg and a melting range of 302–307 K, was applied as two separate layers: one beneath the thermoplastic polyolefin membrane and another above the plaster ceiling. Simulations were carried out for Jashore, Dhaka, and Cox's Bazar on the hottest recorded day of 2024. The dual‐layer roof reduced ceiling peak temperatures by 6.6 K in Jashore, 4.7 K in Dhaka, and 3.25 K in Cox's Bazar, while delaying the thermal peak by approximately 2–3 h. Inner‐wall temperatures remained within 298–304 K, showing stable diurnal moderation. The upper PCM layer reached complete melting during the afternoon, while the lower layer attained a maximum liquid fraction of 0.45, creating a two‐stage buffering effect that extended cooling into the evening. Both layers fully solidified before dawn, confirming daily regeneration. Compared with a conventional roof, the dual‐layer configuration reduced conductive heat flux by nearly 38% and lowered estimated cooling energy demand by approximately 30%. These results demonstrate an effective, climate‐responsive solution for improving thermal comfort in tropical housing.

This paper aims to determine whether regularization improves image reconstruction in electrical impedance tomography (EIT) using a radial basis network. The primary purpose is to investigate the effect of regularization to estimate the network parameters of the radial basis function network to solve the inverse problem in EIT. Our approach to studying the efficacy of the radial basis network with regularization is to compare the performance among several different regularizations, mainly Tikhonov, Lasso, and Elastic Net regularization. We vary the network parameters, including the fixed and variable widths for the Gaussian used for the network. We also perform a robustness study for comparison of the different regularizations used. Our results include (1) determining the optimal number of radial basis functions in the network to avoid overfitting; (2) comparison of fixed versus variable Gaussian width with or without regularization; (3) comparison of image reconstruction with or without regularization, in particular, no regularization, Tikhonov, Lasso, and Elastic Net; (4) comparison of both mean square and mean absolute error and the corresponding variance; and (5) comparison of robustness, in particular, the performance of the different methods concerning noise level. We conclude that by looking at the R² score, one can determine the optimal number of radial basis functions. The fixed-width radial basis function network with regularization results in improved performance. The fixed-width Gaussian with Tikhonov regularization performs very well. The regularization helps reconstruct the images outside of the training data set. The regularization may cause the quality of the reconstruction to deteriorate; however, the stability is much improved. In terms of robustness, the RBF with Lasso and Elastic Net seem very robust compared to Tikhonov.

Cardiovascular diseases, largely driven by atherosclerosis-induced stenosis, remain the leading cause of mortality worldwide. The bifurcation of the brachiocephalic trunk into the subclavian and common carotid arteries is particularly susceptible to disturbed hemodynamics and plaque accumulation. This study presents a computational analysis of the impact of stenosis and bifurcation geometry (45°, 60°, and 75°) on blood flow and oxygen transport using COMSOL Multiphysics®. Pulsatile flow conditions were modeled with coupled laminar flow and transport of diluted species modules to evaluate velocity, wall shear stress (WSS), and oxygen concentration. Results show that stenosis leads to a significant increase in peak systolic velocity (up to ∼31%) and localized WSS (peaking at 16 Pa), especially at lower bifurcation angles. Wider bifurcation geometries (75°) resulted in pronounced flow separation, vortex formation, and reduced oxygen delivery, with concentrations falling as low as 0.10 mol/m 3 in critical downstream regions. These hemodynamic disturbances were most severe in the presence of both wide bifurcation angles and stenotic narrowing. The model was validated against previous numerical and experimental studies, confirming its accuracy. The findings underscore the importance of considering arterial geometry in diagnosing vascular risk and optimizing intervention strategies. Integrating hemodynamic and oxygen transport analysis provides a more comprehensive understanding of stenosis progression and offers a foundation for personalized cardiovascular treatments.