The Gilroy-Phillips model of relaxational jumps in asymmetric double well potentials, developed for the Arrhenius-type secondary relaxations of the glass phase, is extended to a formal description of the breakdown of the shear modulus at the glass transition, the α-process. The extension requires the introduction of two separate parts of the barrier distribution function f(V ), with a different...

Vitrification is a process in which a liquid begins to behave as a solid during cooling without any substantial change in molecular arrangement or thermodynamic state variables. The physical phenomenon of vitrification is relevant to both cryopreservation by freezing, in which cells survive in glass between ice crystals, and cryopreservation by vitrification in which a whole sample is vitrified...

We find that the density dependence of the glass transition temperature of Lennard-Jones (LJ) and Weeks-Chandler-Andersen (WCA) systems can be predicted from properties of the zero-temperature (T=0) glasses. Below a crossover density ρs, LJ and WCA glasses show different structures, leading to different vibrational properties and consequently making LJ glasses more stable with higher glass tran...

the sorption isotherm and state diagram of sundried, golden and sultana raisins were constructed for investigation and comparison of the product stability. the isotherms were measured at 15, 25 and 35 °c using an isopiestic method and the data were modeled with gab model. glass transition temperatures of the products were measured by differential scanning calorimetery (dsc) and fitted to gordon...

sorption isotherm and thermal properties of powders were used for determining stability during storage. garlic slices with 2 mm thickness were dried, using two methods of freeze and cabinet drying. the results showed that, the density, loss of pyruvate and color changes of the freeze dried powder were less than those of the cabinet dried powder. sorption isotherm curves of the both garlic powde...

We use Monte Carlo simulations to study the static and dynamical properties of a Potts glass with infinite range Gaussian distributed exchange interactions for a broad range of temperature and system size up to N = 2560 spins. The results are compatible with a critical divergence of the relaxation time τ at the theoretically predicted dynamical transition temperature TD, τ ∝ (T−TD) −∆ with ∆ ≈ ...

Ordering of the Heisenberg spin glass with the nearest-neighbor Gaussian coupling is investigated by equilibrium Monte Carlo simulations in four and five dimensions. Ordering of the mean-field Heisenberg spin glass is also studied for comparison. Particular attention is paid to the nature of the spin-glass and chiral-glass orderings. Our numerical data suggest that, in five dimensions, the mode...

Birefringence of oxide glass fibers drawn from glass melts through an orifice has been detected previously [H. Stockhorst, R. BruÈckner, J. Non-Cryst. Solids 49 (1982) 471; H. Stockhorst, R. BruÈckner, J. Non-Cryst. Solids, 86 (1985) 105.] This birefringence is a measure of anisotropy in glass structure that can influence fiber performance properties. Birefringence is produced during fiber draw...

It is frequently assumed that in the limit of vanishing cooling rate, the glass transition phenomenon becomes a thermodynamic transition at a temperature TK. However, with any finite cooling rate, the system falls out of equilibrium at temperatures near Tg(>TK), implying that the very existence of the putative thermodynamic phase transition at TK can be questioned. Recent studies of systems wit...

The aim of this study was to elucidate the role of the two main mechanisms used to explain the stabilization of proteins by sugar glasses during drying and subsequent storage: the vitrification and the water replacement theory. Although in literature protein stability is often attributed to either vitrification or water replacement, both mechanisms could play a role and they should be considere...