70 publications from this institution
Ferro-siliceous concrete (FSC), as a sacrificial material, is used in European Pressurized Water Reactor. This paper presents an experimental investigation on the performance of FSC with and without polypropylene (PP) fibers subjected to elevated temperatures. Mechanical and physicochemical properties of FSCs were studied at both ambient and high temperatures. The occurrence of spalling, compressive strength, splitting tensile strength, mass loss, porosity, chemical composition, crystalline phase, and thermal analysis of FSCs before and after exposure to various temperatures (200, 400, 600, 800, and 1000°C) were comprehensively investigated. Ultrasonic pulse velocity (UPV) propagation in FSCs at different temperatures was determined by ultrasonic testing technique, and the relationships between strengths and UPV of FSCs were eventually obtained. The results indicated that, (1) the critical temperature range of FSCs was 400–600°C; (2) the compressive strength-UPV and splitting tensile strength-UPV relationships were Weibull distribution and exponential form, respectively; (3) compared to unheated FSCs, the porosity values were more than trebled after exposure to 1000°C.
A hybrid supercapacitor based on spinel Li2Mn4O9 and activated carbon (AC) was fabricated. The electrochemical performance of the capacitor was studied by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge in different aqueous electrolytes such as 1M LiNO3, Li2SO4, NaNO3 and KNO3 solution. A maximum specific capacitance of 261Fg−1 was obtained for the Li2Mn4O9 single electrode between 0 and 1.4V. The Li2Mn4O9/AC hybrid supercapacitor showed a sloping voltage profile from 0 to 1.4V and delivered an energy density of 53Whkg−1 based on the total weight of the active electrode materials. The hybrid capacitor exhibited a desirable profile and maintained over 80% of its initial energy density after 1000 cycles, indicating that Li2Mn4O9 has excellent cycling performance and structural stability in aqueous electrolyte. The hybrid supercapacitor also exhibited an excellent rate capability, even at a power density of 1250Wkg−1, it had a specific energy 29Whkg−1 compared with 48Whkg−1 at the power density of about 417Wkg−1.
