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In our previous studies, we have found the synergistic combinations of stabilizers which follow different mechanisms of stabilization and are approved for food contact applications. The present attempt is to test the potentials of those systems in stabilizing c-sterilized lowdensity polyethylene (LDPE). The results were discussed by comparing the stabilizing efficiency of mixtures with and without phenol systems as well as with their counterparts of isotactic polypropylene (iPP) and ethylene-propylene copolymers (EP) matrices. LDPE has been melt-mixed with tertiary hindered amine stabilizer (tert-HAS), oligomeric HAS stabilizer, phenolic and organo-phosphite antioxidants and subjected to c-sterilization. Stabilization in terms of changes in oxidation products, tensile properties, yellowing and surface morphology was evaluated by FT-IR spectroscopy, Instron, colorimetry, and scanning electron microscopy (SEM), respectively. The results of the present study confirm the validity of those systems for protecting various polyolefins against c-sterilization. The results showed that the synergism, antagonism and the trend in stabilization efficiency of the binary, ternary and quaternary stabilizer systems were almost similar in LDPE, iPP and EP matrices. The binary system of oligomeric HAS and tert-HAS has shown the antagonistic effect of stabilization, whereas their combination with organophosphite has exhibited synergistic effect even at higher doses of c-sterilization. The combination of oligomeric HAS, tert-HAS, organo-phosphite and hindered phenol exhibited improved stabilization efficiency than single or binary additive systems. The phenol systems have shown long term of stability than that of phenol-free systems. It was found that the consumption of oligomeric stabilizer significantly depends on the components of stabilization mixture. It was concluded that the stability of polyolefins (LDPE, iPP and EP) against c-sterilization can be achieved by blends of different stabilizers which are approved for food contact applications.

Zn-and Ca-doped ErBa 2 Cu 3 O 7−δ were successfully prepared via coprecipitation method using metal acetates as the starting salts. The precipitated samples were calcined for 20 h at 900°C and sintered at 920°C for 24 h. All heat treatments were carried out under oxygen environment. Results show that there is a selectivity of the doping site depending on the ionic radius of the dopant. Furthermore, increase in the critical temperature, T c , was observed in 0.05 mole of calcium and zinc doped samples. The difference in ionic radius of the dopant led to the increase in porosity as the ionic radius decreases. On the other hand, structural distortion increased as the difference of ionic radius became larger.

The solid-state fuel cell is the most widely adopted energy-generating technology in the world for which different oxide-ion conductors of pervoskite structures have been recently investigated for the application in the intermediate temperature-solid oxide fuel cells (IT-SOFCs). In the present work, samples of single substituted BIMEVOX i.e., BIBIVOX (Bi 2 V 1-x Bi x O 5.5-x/2) were prepared in the composition range 0 ≥ x ≥ 0.20 using bottom up sol-gel method. XRPD, FT-IR, DTA, SEM, EDS, and AC impedance spectroscopy were used for the investigation of the correlation between the structural phase stability and oxide-ion performance of the BIBIVOX materials. It has been found that orthorhombic, β, and incommensurate tetragonal, γ′-phases were stabilized at room temperature for compositions with x=0.15 and x=0.20, respectively. The enthalpy of β-γ and γ′-γ transition exhibited a general drop with increasing Bi content. The higher value of conductivity of the substituted compound as compared to the parent compound can be attributed to the increased oxygen vacancies generated as a result of cation doping. AC impedance spectroscopy reveals the fact that this ionic conductivity is mainly due to the grain contribution.

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