[en] A new set of expressions has been derived for the determination of the activation energy E of a thermoluminescence (TL) peak. Unlike those previously existing in the literature, the present expressions take into account the variation of the symmetry factor μg(x) with u_m=(E/kT_m) where x is the fractional intensity, k the Boltzmann constant and T_m the peak temperature and prior knowledge of the order of kinetics b is not required. The applicability of the present expressions have been tested using both numerically generated and experimental thermoluminescence peaks. (author)

[en] It has been investigated the interrelationship between the changes occurred in IR spectra of initial and gamma irradiated composite samples obtained on the basis of Si nanoparticles with copolymer P(VDF-TrFE) of polyvinylidene fluoride with tetraftoretilen and electrical properties It is shown that, optical properties of P(VDF-TeFE)/nano-Si composites change depending on the amount of filler and irradiation dose and there is a one-valued relationship between this change and electrical properties of composites. Based on the analysis of IR spectra obtained before and after gamma radiation of P (VDFTeFE)/nano-Si composites, we can say that the crystallization rate of the system is increasing as a result of interaction of the active centers formed on the matrix after radiation with the surface of Si nanoparticles on the interphase boundary. The optical properties of P (VDF-TeFE)/nano-Si composites obtained based on the P (VDF-TeFE) polymer change depending on the amount of filler and the radiation dose, and there is a one-valued relationship between this change and the electrical properties of the composites.

[en] The purpose of this short communication is to demonstrate that the compensation effect is not general for the individual material but appears in the comparison of the pre-exponential factors and activation energies among various materials. (orig./MM)

[en] Highlights: ► The microstructure evolution of cold-rolled Zr 702 during annealing was studied. ► The recrystallization kinetics of cold rolled Zr 702 was determined. ► The JMAK exponent increased with increasing temperature and rolling reduction. ► The activation energy for recrystallization of cold-rolled sheets was obtained. -- Abstract: Using the hardness test, we determined the recrystallization kinetics of cold-rolled Zr 702. The rate of the recrystallization process increased with increasing annealing temperature and rolling reduction. The Johnson–Mehl–Avrami–Kolmogorov (JMAK) exponent obtained was less than 1, which also increased with increasing annealing temperature and rolling reduction. The activation energies for the recrystallization of the 38.9% and 71.0% cold-rolled sheets were 232 kJ/mol and 251 kJ/mol, respectively

[en] The effect of γ-quanta on the electrical conductivity of GaS layered single crystal, pure and alloyed with 0.1at % Yb and Sm has been studied at a temperature range of 100-300K. It has been established that the electrical conductivity of crystals decreases due to the formation of acceptor- and donor-type levels corresponding to 1.56 and 0.16 eV activation energy as a result of insertion of the dopant atom Yb into the GaS matrix. Although the inclusion of the dopant atom Sm partially reduces the conductivity of the GaS crystal (∼0.24 eV) at 100–300K, its conductivity is of a metallic character at 100-190K and it is semiconductor in the high-temperature regions

[en] A new approach to study of gas-solid exchange processes is offered and tested. It is known, that under gas environment storage at certain temperature T with pressure p there are two competitive processes - sorption and desorption. The methodics for activation energies of sorption and desorption definition by thermodesorption experiments and without any suppositions on parameters value a (reaction order) and K_s0 (sorption constant) are presented

[en] Certain experimental results on diffusion of carbon in beryllium are considered and D₀ and Q parameters of this process are shown to be linked by D₀=A_exp(B/Q) dependence (compensative effect). Values of diffusion activation entropy calculated using this dependence constitute 15-20 R. These values are too high to be explained on the ground of elastic model. There is a number of process peculiarities, in particular, high value of activation energy and low level of carbon diffusion mobility in beryllium. Practically all difficulties may be overcome in case one can assume that carbon diffuses in form of mixed pairs of atoms one of which occupies interstitial position, while the other-substitution one

[en] A new method is described to obtain the trap parameters of thermoluminescence (TL) glow curves including several peaks. The method starts with obtaining the trap parameters of the higher temperature glow peak. The evaluation of the trap parameters of this peak starts with determining the order of kinetics b. Two different equations are developed to estimate b. Thereafter, the activation energy E (eV) and then the frequency factor S (s^-1) or the pre-exponential factor S'' (s^-1) of this peak are determined. The shape of this peak is then fitted to an equation of the order of kinetics depending on the determined value of b. Using the previously determined shape, the higher temperature peak is scaled up to fit the decreasing portion of the combined peak. The procedure is then repeated to account for each of the remaining peaks in the glow curve. (author)

[en] The dehydration mass loss of samples of montmorillonite (a layered hydrated silicate) was measured in an environment at constant temperature and at constant undersatured water vapour content. The hydration curves were analyzed by assuming the model of thermally activated, monoenergetic and first-order process compatible with the experimental results. Two dehydration kinetics with activation energies (0.21+-0.02) eV and (0.34+-0.02) eV were found that can be related to the existence of two kinds of water (structured and nonstructured) in the hydrated silicate interlayers. The possibility of an icelike structure of a fraction of the adsorbed molecules is briefly discussed. The experimental results show, furthermore, that in the investigated hydration range (up to about 10% in mass) the fraction of structured water has a maximum when the hydration is about 6%. (author)

[en] Labile Wigner energy, known as the discomposition effect which comes from the displacement of atoms in a solid, especially a graphite carbon in our respects, caused by neutron radiation, has been focused on one of major considerations for nuclear graphite waste management. Because of the unstable behavior of the irradiated graphite including an emissive nuclides and relating radioactive contents as well as a thermal shock at a sudden heat exposure through the irradiated graphite body, the dissipation of the Wigner energy in a controlled manner has to be studied. In our previous studies, the kinetics of a Wigner energy release have shown very complicated forms such that the overall reaction rates has been considered as first-order rate equations with variable activation energy contents like the following general equation