The impact of ionic contribution to dielectric permittivity in 11CB liquid crystal and its colloids with BaTiO3 nanoparticles

The European Physical Journal E - Coexistence curves in mixtures of limited miscibility with the lower critical consolute temperature (LCT), of 3-picoline with deuterium oxide (D2O), and D2O/H2O...     

The tricritical point in an ethanediol-nitroethane-cyclohexane-methanol solution

Applying the polythermal method the coexistence region of three liquid phases in an ethanediol-nitroethane-cyclohexane-methanol system has been found for several temperatures. From this the temperature and composition of the tricritical point has been determined as T _TCP = 37.5 ± 1°C and mass fraction :x _ethanediol = 0.09 ± 0.01, x _nitroelhane = 0.45 ± 0.01 x _{cycelohcexane} = 0.40 ± 0.02, x _methanol = 0.060 ± 0.005. The point at which, for a given polytherm, the transition from a two-phase to a three-phase region takes place at the highest temperature is identified as the critical end-point.

Functions of temperature versus heights of menisci separating the individual phases have been determined for selected values of concentration.     

Critical properties of nitrobenzene + n-alkanes solutions

Coexistence curves and critical parameters are given for solutions of nitrobenzene with a series of n-alkanes from n-pentane to n-eicosane. By mixing suitable n-alkanes, a pseudosolvent was obtained and the critical properties of the nitrobenzene + pseudo-n-alkane solution were compared with those of the corresponding binary solution.     

Dual field nonlinear dielectric spectroscopy in a glass forming EPON 828 epoxy resin

Results of the dual field nonlinear dielectric spectroscopy (NDS) studies in supercooled glass forming epoxy resin EPON 828 are presented. For the NDS, changes of dielectric permittivity induced by DC (rectangular) or AC (sine-wave) pulses of a strong electric field were probed by a weak radio frequency electric field. A clear stretched exponential (x < 1) decay after switching off the DC pulse and a single exponential decay (x = 1) after switching off the AC pulse were found. The same results are presented for preliminary studies in superpressed low molecular glass former di-isobutyl phthalate. This observation may be considered as an argument for the heterogeneous picture of supercooled glass forming materials. The temperature dependences of the stationary responses related to DC and AC strong electric field excitations are also shown. The sensitivity of the applied set up made it possible to detect NDS outputs even for electric fields E(strong) < 10 kV cm(-1), qualitatively weaker than in similar 'nonlinear, dielectric' experimental studies on glass forming materials carried out so far.     

Evaluation of quality changes of beetroot juice after high hydrostatic pressure processing

ABSTRACT

Freshly squeezed commercially available beetroot juice, a popular beverage in Poland, is a good source of betalains, but as a root vegetable can contain undesirable microflora from the soil. The objective of this study was to investigate the effect of new preservation technique, high hydrostatic pressure, on the beetroot juice quality. Samples of beetroot juice were treated with pressure 300, 400 and 500?MPa/20°C/up to 10 min. Reduction in the total count of spoilage microorganisms reached 3.8, 4.1 and 4.5 log cfu/mL, depending on the pressure. After this treatment beetroot juice showed a 11.3–12.2% decrease in betacyanins content and 7.7–8.9% in betaxanthins content. A significant reduction of the number of spoilage microorganisms with a slight degradation of pigments indicates the possibility of industrial application of high pressure to the preservation of beetroot juice.