“
“A series of Co3-xMnxO4 (x = 0.1-1.0) multiferroic cubic spinel ceramics were prepared to study the effect of Mn substitution at Co site on the crystal structures and dielectric properties. PF-00299804 cell line No significant change in the structural

symmetry was observed with increasing x up to 1.0. A linear increase in lattice parameter with x is attributed to the substitution of Co3+ by Mn3+ (large ionic radii) at the octahedral sites. An antiferromagnetic-type ordering of Co3O4 changes to ferrimagnetic-type order after incorporation of Mn. The effect of Mn substitution on the dielectric constant and loss tangent was studied over a wide range of frequency (75 kHz-5 MHz) and temperature of 150-450 K. The measured value of room temperature ac conductivity at 1.0 MHz was found to increase from 2.0 x 10(-6) to 4.4 x 10(-4) Omega(-1) cm(-1) and follows power law (sigma(ac) = A omega(s)) behavior. The dielectric constant epsilon’(omega) shows a weak frequency dispersion and

small temperature dependence below 250 K for all ceramic samples. However, a strong temperature and frequency dependence on epsilon’(omega) was observed at higher temperature (>250 K). The temperature dependent epsilon’(omega) data show the existence of room temperature ferroelectricity in all prepared samples. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3182722]“
“This Study investigated the influence of high-pressure processing on the morphology and permeability of low-density Polyethylene (LDPE) films used for food packaging. This was done by monitoring the crystallinity, melting temperature (T(m)) and oxygen transmission rate selleck inhibitor (OTR) of the materials before and after the pressure treatments. A first set Of Pouches made from the LDPE films were filled with 95% ethanol then pressured at 200, 400, 600, and 800 MPa for 5 and 10 min at 25 and 75 degrees C. The crystallinity and T(m) of the films

were measured using differential scanning Copanlisib calorimetry (DSC). X-ray diffraction (XRD) was also used to determine the crystallinity. A second set of LDPE Pouches were similarly made but a half of them were filled with 95% ethanol and the other half filled with distilled water. These second set of Pouches were pressured at 200, 600, and 800 MPa then their OTR tested. Results of the DSC experiments showed that the T(m) increased with increasing pressure intensity but the crystallinity changes were not detectible. The XRD method on the other hand, showed significant (P < 0.05) crystallinity increases with increasing pressure treatments. The gas permeability analyses showed decreasing OTR’s with increasing high-pressure intensity treatments. The OTR in the pouches filled with the 95%, ethanol was slightly lower than that Of the pouches filled with water. These findings allowed us to better anticipate the behavior of LDPE films used to package high-pressure processed foods. (C) 2008 Wiley Periodicals, Inc.