Critical phenomena and renormalization-group theory

Dynamic properties, derived from dielectric relaxation spectra of glass-formers at variable temperature and pressure, are used to characterize and classify any resolved or unresolved secondary relaxation based on their different behaviors. The dynamic properties of the secondary relaxation used include: (1) the pressure and temperature dependences; (2) the separation between its relaxation time τβ and the primary relaxation time τα at any chosen τα; (3) whether τβ is approximately equal to the independent (primitive) relaxation time τ0 of the coupling model; (4) whether both τβ and τ0 have the same pressure and temperature dependences; (5) whether it is responsible for the “excess wing” of the primary relaxation observed in some glass-formers; (6) how the excess wing changes on aging, blending with another miscible glass-former, or increasing the molecular weight of the glass-former; (7) the change of temperature dependence of its dielectric strength Δeβ and τβ across the glass transition temperature Tg; ...

Classification of secondary relaxation in glass-formers based on dynamic properties.

An intriguing problem in condensed matter physics is understanding the glass transition, in particular the dynamics in the equilibrium liquid close to vitrification Recent advances have been made by using hydrostatic pressure as an experimental variable These results are reviewed, with an emphasis in the insight provided into the mechanisms underlying the relaxation properties of glass-forming liquids and polymers

https://iopscience.iop.org/article/10.1088/0034-4885/68/6/R03/pdf

Supercooled dynamics of glass-forming liquids and polymers under hydrostatic pressure

Evaluation of amorphous solid dispersion properties using thermal analysis techniques.

/pdf/dislocations-in-solids-1gaufoliyg.pdf

Dislocations in solids

For the exponent ψ which describes a critical anomaly of the nonlinear dielectric effect (NDE) and the electro-optic Kerr effect (EKE) in critical solutions, theoretical models predict: ψ NDE =ψ EKE =ψ theor =γ-2β. An experiment gave ψ NDE (≃0.37)<ψ theor (≃0.59)<ψ EKE (≃0.8). For all other experimental results, however, the agreement with the theory is good. In this paper it is shown that also both of the above relations may be valid. This result is based on the assumption that the NDE and the EKE exhibit a mixture of both a nonclassical and a classical type of behavior of critical fluctuations

Kerr effect and the nonlinear dielectric effect on approaching the critical consolute point.

The properties of glass are determined not only by temperature, pressure, and composition, but also by their complete thermal and pressure histories. Here, we show that glasses of identical composition produced through thermal annealing and through quenching from elevated pressure can result in samples with identical density and mean interatomic distances, yet different bond angle distributions, medium-range structures, and, thus, macroscopic properties. We demonstrate that hardness is higher when the density increase is obtained through thermal annealing rather than through pressure-quenching. Molecular dynamics simulations reveal that this arises because pressure-quenching has a larger effect on medium-range order, while annealing has a larger effect on short-range structures (sharper bond angle distribution), which ultimately determine hardness according to bond constraint theory. Our work could open a new avenue towards industrially useful glasses that are identical in terms of composition and density, but with differences in thermodynamic, mechanical, and rheological properties due to unique structural characteristics.

Unique effects of thermal and pressure histories on glass hardness: Structural and topological origin

Results are presented of temperature and pressure studies of static dielectric permittivity (epsilon) and the nonlinear dielectric effect (NDE) in the isotropic phase of smectogenic n-cyanobiphenyls: 9CB, 10CB, and 12CB (4-cyano-4'-n-alkylbiphenyl, n = 9, 10, and 12). For the mentioned properties, pretransitional effects can be well portrayed by applying the relations used for the isotropic phase of nematogens, where evidence of the quasicritical, fluidlike behavior with exponents alpha approximately 0.5 and gamma = 1 exists. This kind of behavior one can also observe on approaching the isotropic-smectic A transition. NDE studies in 10CB and 12CB made it possible to determine the pressure evolution of the discontinuity (delta T) of the I-SmA transition. It was found that pressure first decreases the discontinuity of the transition, and that next a gradual rise appears. This behavior is unlike the one observed for the isotropic-nematic transition, where only an increase of delta T with rising pressure was observed.

Quasicritical behavior of dielectric permittivity in the isotropic phase of smectogenic n-cyanobiphenyls

Influence of intermolecular interactions on the sign of dTC/dp in critical solutions

Alicyclobacillus acidoterrestris, a thermoacidophilic and spore-forming bacterium is one of the important target micro-organisms in the quality control of acidic canned foods. High pressure pasteurization (HPP) at 50°C was used for the inactivation of A. acidoterrestris spores in apple juice. Pressure applied both in a continuous and oscillatory mode gave the best results when 200 MPa was used. Increasing the pressure to 500 MPa, as well as lowering its value to 100 MPa, had an adverse effect on the effectiveness of the process. The best results were achieved with the use of a combined treatment, involving oscillatory pressurization at 200 MPa, followed by holding the sample for 60 min at atmospheric pressure and subsequent pressurization at 500 MPa, resulting in a reduction in the spore count of 6.15 log. Nisin significantly enhanced the effect of HPP at 300 MPa. Using pressure of 200 MPa for 45 min with a nisin concentration of 250 IU/mL enabled total spore inactivation (over 6 log). No significant effe...

Sylwester J. Rzoska

Papers

Kerr effect and the nonlinear dielectric effect on approaching the critical consolute point.

Unique effects of thermal and pressure histories on glass hardness: Structural and topological origin

Quasicritical behavior of dielectric permittivity in the isotropic phase of smectogenic n-cyanobiphenyls

Influence of intermolecular interactions on the sign of dTC/dp in critical solutions

The combined effect of high pressure and nisin or lysozyme on the inactivation of Alicyclobacillus acidoterrestris spores in apple juice