Comparison on electrical properties of pure Y2O3, bismuth doped Y2O3, zinc doped Y2O3, bismuth and zinc codoped Y2O3 prepared by sol-gel method

Yttrium oxide is widely studied nowadays as a substitute for SiO2 which is a well-known dielectric material. The uniqueness of yttrium oxide is that it has a high melting point (2430 °C) which is higher than other host materials like alumina, zirconia and yttrium aluminium garnet. Hence an attempt was made to add the dopants, bismuth and zinc simultaneously to the yttrium oxide lattice and to study their properties as a dielectric material. Also the dependence of their electrical properties on structure, particle size and morphology is analysed. Pure Yttrium oxide, bismuth doped yttrium oxide, zinc doped yttrium oxide and bismuth and zinc codoped yttrium oxide samples of 0.5 weight percentage of yttrium precursor as dopant concentration are synthesized by simple precipitation technique, sol-gel method. Electrical properties of the samples are studied and a comparative study is done on the doped and codoped samples and it was found that codoped samples show better electrical properties compared with single dopant samples.

Investigation of Natural Effective Gamma Dose Rates case study: Ardabil Province in Iran

Gamma rays pose enough energy to form charged particles and adversely affect human health. Since, the external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined, natural background gamma dose rates and corresponding annual effective doses were determined for selected cities of Ardabil province from 2009 to 2010. Outdoor gamma dose rates were measured using an Ion Chamber Survey Meter in 105 locations in selected districts. Average absorbed dose for Ardabil, Sar-Ein, Germy, Neer, Shourabil Recreational Lake, and Kosar were determined as 265, 219, 344, 233, 352, and 358 nSvh-1, respectively. Although dose rates recorded for Germi and Kosar are comparable with some areas with high natural radiation background, however, the dose rates in other districts are well below the levels reported for such locations. Average annual effective dose due to indoor and outdoor gamma radiation for Ardabil province was estimated to be 1.73 (1.35-2.39) mSv, which is on average 2 times higher than the world population weighted average

Background radiation and individual dosimetry in the costal area of Tamil Nadu, India.

South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2×7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1)

Influence of europium doping on conductivity of LiNiPO4

Europium doped LiNiPO4 and undoped LiNiPO4 were prepared by Pechini method. Compound formation temperature was confirmed from thermogravimetry and differential thermal analysis (TG/DTA). Powder X-ray diffraction (XRD) pattern confirmed the formation of pure LiNiPO4 compound with an orthorhombic structure. The conductivity and modulus analyses of the samples were carried out at different temperatures and frequencies using the complex impedance spectroscopy technique. The conductivity parameters such as ion hopping frequency and the charge carrier concentration term were calculated using Almond and West formalisms. An increase of one order of magnitude in the ionic conductivity has been observed for 1.0% Eu-doped LiNiPO4. (mole fraction). The complex modulus studies suggest the presence of non-Debye type of relaxation in the materials