Fibers and fiber cocktails to improve fire resistance of concrete

Hybrid organic–inorganic resin matrix, i.e., hexa[3,4-dicyano]-phenyl phosphonitrile trimer (HPPT) has been prepared by the reaction of hexachlorophosphonitrile and 4-hydroxyphthalonitrile in the presence of sodium hydride which on heating at 300 °C yielded a high-temperature-stable highly crosslinked hybrid resin (C-HPPT). The elemental analysis (C, H, and N), FTIR, and ¹H and ¹³C-NMR studies were used to characterize the synthesized hybrid resin. The thermal analysis studies viz. TG and DSC were also carried out to determine the thermal stability and glass transition temperature of the cured resin. The isothermal study of the cured resin after 300 h at 300 °C showed only a mass loss of 4.36%.     

Determination of plastic zones in compact specimens of aluminium

Plastic zones in notched compact specimens were made visible by recrystallization. The material tested was annealed AlMgSil alloy. The shape and dimensions of the zones as well as the distribution of plastic deformation were studied as a function of notch geometry (notch tip radius, depth of the notch) and of the distance measured from the surface of the specimens. The advantages and limits of the recrystallization method are discussed.