Thermal shocks in ceramics. Part 1. The contemporaneous theories

Opisano zjawiska zachodzące na powierzchni próbki podczas szoku cieplnego. Wyprowadzono, ściśle, wzory określające współczynniki odporności na szok cieplny: R (dla ciała termosprężystego) i R’’’’ (dla ciała termosprężysto-kruchego). Pokazano analogię pomiędzy współczynnikami R a Rst.Phenomenon taking place on the surface of the sample during thermal shocks are described in this work. Formulae, rigorous defining resistance coefficients to thermal stress: R (for thermo-elastic solid) and R’’’’ (for thermo-elastic-brittle solid), were derived. Analogy between R and Rst coefficients is shown

Explosive Properties of 4,4’,5,5’-Tetranitro-2,2’-bi-1H-imidazole Dihydrate

This paper reports measured explosive properties of 4,4’,5,5’-tetranitro-2,2’-bi-1H-imidazole dihydrate (TNBI•2H2O). Non-isothermal kinetics analysis, calorimetric measurements, detonability tests, small-scale shock reactivity tests (SSRT), detonation velocity measurements and cylinder tests were performed. The results of the cylinder tests were used to determine the acceleration ability of TNBI•2H2O. Some experiments were conducted also with TNT, NTO, FOX-7 and RDX. Our experimental studies have shown that TNBI•2H2O is a thermodynamically stable compound, surpassing TNT with regard to its energetic and detonation parameters. The results of the SSRT indicate that this material has better performance in small charges than RDX, FOX-7 and NTO

On the Crystal and Magnetic Behavior οf ScFe4Al8ScFe_{4}Al_{8} Single Crystal

Nuclear and magnetic properties of the $ScFe_{4}Al_{8}$ single crystal were found to exhibit unparalleled complexity of nuclear and magnetic structures. Our previous neutron measurements revealed presence of two modulation vectors, both along [ε, ε, 0], however with different critical temperatures. Recent experiments forced us to revise our knowledge of the structural ordering in the sample. So far, the crystal structure of this alloy, being of $ThMn_{12}$-type, has never been questioned

Effect of Annealing in Multicomponent bcc Alloys

Multicomponent single phase alloys were synthesized according to the idea of iron-average atom system. X-ray diffraction shows formation of bcc phase and traces of unidentified phase. Mössbauer spectra indicate presence of two components with different hyperfine magnetic field distributions. The high field component corresponds to the majority ferromagnetic phase. Few per cent of iron builds low field component. The dominant effect of annealing consists in an increase of the low field component