Crimson Publishers-Material Science

Abstract Geopolymer cements were prepared using a bioactive waste like Egg Shell Powder (ESP) and Commercial Calcium Carbonate (CCC). These geopolymer cements were prepared by adding 6M phosphoric acid as a chemical hardener to siliceous clay containing 0, 3, 6, 9, 12 and 15wt. % from ESP and CCC. Results showed that Toshka clay (T-C) which is siliceous material, and it is mainly composed of kaolinite, illite and quartz phases. This was confirmed by the XRD patterns, and other trace minerals have also been found. The ESP is composed of calcium carbonate, CaCO 3 . Results showed that the bulk density of the prepared geopolymer cements improved and increased with the gradual replacement with ESP or CCC at the expense of the T-C only up till 12wt. %, while the water absorption and apparent porosity decreased, whereas the flexural and compressive strengths improved and enhanced. However, all the characteristics of geopolymer cements based on ESP are higher than those based on CCC. The opti...

Abstract  Almost two decades ago, we reported - and patented - by the first time on a simple chemical route aiming to synthetize stable room-temperature magnetic bulk carbon/graphite. We obtained the experimental confirmation that its magnetism originates from defects in the structure (and not from ferromagnetic impurities) from direct measurement of the local magnetic field using 13C nuclear magnetic resonance associated to the numerical results obtained from DFT (Density-Functional theory) calculations. We have also developed the chemical synthesis route to obtain nanofluid magnetic carbon/graphite. In this short review of our own work, we briefly show these findings as well as the main physical and chemical properties of this material and recent results aiming biotechnological and medical applications. From theoretical calculation, we have analyzed its possible use as a contrast, for example, in the MPI (Magnetic Particle Imaging) technique. Finally, we show here the potential o...