Due to the threat of terrorist activities worldwide, research on the protection of building structures from the effects of explosions is critical in order to avoid catastrophic damage to buildings. Protecting our infrastructures means protecting lives. Metallic foam is an economical, light-weight and recyclable material used as a sacrificial cladding to protect structures. Its efficient energy absorption enables metallic foam to mitigate the blast energy acting on the protected structure. This paper describes our numerical investigation of the protective performance of metallic foam cladding on reinforced concrete (RC) structural members using LS-DYNA. In the numerical model, Modified Honeycomb (Material 126) from the LS-DYNA material library was used to represent the aluminium foam while Continuous Surface Cap Model (Material 159) was selected to model the behaviour of concrete. The numerical model was validated by field blast testing results. Using the validated numerical model, parametric studies were conducted to assess the influence of different foam properties on the pressure-impulse (P-I) diagrams of the foam-protected RC slabs. The influence of the thickness of the RC members was also investigated. The derived P-I diagrams will prove useful in the preliminary design of the foam cladding on RC members.

Numerous studies have shown that superhydrophobic surfaces are attributed by micro/nano structures and low surface energy film. In the present study, an ultraviolet laser process for fabricating micro-groove structures on an aluminium alloy surface and subsequent chemical treatment are carried out to improve surface hydrophobicity. We use the scanning space μ as a variable to observe the wetting state, which shows that as the scanning space μ increases the energy barrier can be overcome and demonstrate Cassie-to-Wenzel transition. The two liquids (water and glycerol) method is used to test the surface energy. The finding reveals that surface morphology and surface energy are assessed in correlation with wettability. The laser textured surface with chemical modification decreases the polar component of the surface energy and enhances the superhydrophobicity. This work presents a novel method of fabricating a stable superhydrophobic surface.

Carotid stenting near the bifurcation carina is associated with adverse events, especially in-stent restenosis, thrombosis, and side branch occlusion in clinical data. This study is aimed at determining the potential biomechanical mechanisms for these adverse events after carotid stenting. The patient-specific carotid models were constructed with different stenting scenarios to study the flow distribution and hemodynamic parameters, such as wall shear stress (WSS), flow velocity, relative residence time (RRT), and oscillating shear index (OSI) in the carotid bifurcation. The results suggested that the existing stents surely reduced blood flow to the external carotid artery (ECA) but enhanced local flow disturbance both in ECA and stented internal carotid artery (ICA), and the inner posterior wall of the stented ICA and the outer posterior wall of ECA might endure a relatively low level of WSS and remarkably elevated OSI and RRT. In addition, the implanted stent leads to more ECA adverse flow than ICA after stenting. While disturbed flow near the strut increased as stent length increased, blood flow and areas of local flow disturbance in ECA slightly decreased as stent length increased. In conclusion, the results revealed that ECA might be in relatively high levels of abnormal local hemodynamics after stenting, followed by stented ICA, leading to potential adverse events after intervention.