Predicting explosion parameters is an important step when planning for blast tests or the design of blast resistant buildings. This paper presents a comparison of recorded pressure that was reflected on the surface of reinforced concrete slabs with and without EPS (Expanded Polystyrene) foam retrofit measured from a detonation of 2.7 kg of non-confined plastic explosive. Two 50 MPa reinforced concrete slabs measuring 1.0x1.0x0.08 m, simply supported on two sides were tested. The explosive was suspended at a distance of 2.0 m from the upper surface of the slabs; one of the slabs had 5.0 cm thick foam on the top side. Eight piezoelectric pressure sensors were positioned at a distance of 2.0 m from the explosive. Results showed that the foam retrofit reduced the reflected pressure by approximately 57% when compared to the slab without EPS foam retrofit.
5 February 2021 in Journal of the Brazilian Society of Mechanical Sciences and Engineering
The aggregation behavior of the non-ionic surfactant Renex-100 in aqueous solutions and mesophases was evaluated by SAXS in a wide range of concentrations, between 20 and 30 °C. Complementary, water interactions were defined by DSC curves around 0°C. SAXS showed that the system undergoes the following phase transitions, from diluted to concentrated aqueous solutions: 1) isotropic solution of Renex aggregates; 2) hexagonal mesophase; 3) lamellar mesophase; and 4) isotropic solution. DSC analysis indicated the presence of interfacial water above 70wt%, which agreed with the segregation of free water to form the structural mesophases observed by SAXS bellow this concentration
18 December 2019 in Journal of the Brazilian Society of Mechanical Sciences and Engineering