Radon exhalation rates from zircon sands and ceramic tiles in Italy.

Naturally occurring radionuclides in building materials are sources of external and internal exposure in dwellings. External radiation exposure is caused by the gamma radiation originating from members of uranium and thorium decay chain and from 40K. Internal radiation exposure, mainly affecting the respiratory tract, is due to the short-lived daughter products of radon which are exhaled from building materials into room air. The objective of this study is to measure the radon exhalation rates from zircon materials, flours and sands, used as raw materials in the porous fired tiles body and from the final products (porcelain tiles usually commercialized in Italy). The radon exhalation rates for the zircon flours and sands ranged from 0.17 to 1.9 Bq kg−1 h−1, and from 0.090 to 0.20 Bq kg−1 h−1; 222Rn exhalation rates for most of the porcelain stoneware tiles are near or below the minimum detectable limit (LLD) of 0.0004 Bq kg−1 h−1

Natural radioactivity in Italian ceramic tiles

Zircon is the mostly widely occurring zirconium-containing mineral mined commercially. Thorium and uranium may substitute for zirconium in the zircon crystal lattice. The radioactivity levels in zircon lies typically within the ranges 500\u20131000 Bq kg−1 for 232Th and 1000\u20135000 Bq kg−1 for 238U [1]. One of the most important use of zircon is as opacifier for ceramic tiles. Body of ceramic tiles is a mixture of different raw materials, including: clays, quartz materials and feldspathic materials. The body may be glazed or left unglazed. Due to the presence of zircon in the glaze or in the body, ceramic tiles can show natural activity concentration significantly higher than the average values of Earth\u2019s crust. This study contains a summary of results obtained by a survey on Italian ceramic tiles collected over three years (2005\u20132007). About one hundred ceramic tiles were analysed. The survey consisted of measurement of 226Ra, 232Th and 40K activity concentrations and of the gamma-index [2] and radium-equivalent [3, 4] calculation. The activity concentrations of 226Ra, 232Th and 40K result in the order of 100, 50 and 500 Bq kg−1, respectively. Gamma index and radium equivalent activity have been found well below the acceptable limit in most of the samples

New dielectric and semi conducting hybrid inorganic-organic material based on Zr(O(CH2)3CH3)4, glycerol and EMIm TFSI ionic liquid

Multifunctional hybrid materials combining intimately mixed organic and inorganic components con yield high-performance materials with properties not found in either component individually. Combining inorganic and organic structures on a molecular scale to form glasslike materials is the challenging task due to very different formation reactions of inorganic and organic networks. A new hybrid inorganic-organic material is syntheses by sol-gel method using Glycerol and Zirconium(IV)butoxide, Zr(O(CH2)3(CH2)4) as precursors. This material is also doped by means of EMImTFI ionic liquid which is insoluble in water. The material is characterized from: a) three-dimensional structure where Zr atoms are bound between them by means of molecular organic fragments b) electrical activation by means of EMImTFSI Ionic liquid. The elemental composition of the material [Zr(C11O4H31)] has been determined by CHN analyzer and ICP-AES measurements. FT-IR and Raman spectroscopy investigations have been performed in order to study the molecular structure of the material and interactions of the EMImTFSI with the host networks. Differential Scanning Calorimetry measurements show the presence of two glass transition temperature T. The broad band dielectric spectroscopic measurements have carried out in the range of 10-2Hz to 10 MHz between -100\ub0C to 100\ub0C. The conductivity of the material [Zr(C11O4H31)] has been found to be in the order of 10-12 to 10-11 S/cm, so it con he defined as a dielectric material. After the addition of ionic liquid the conductivity is increased udue to the creation of free charge carriers in the host material

Erratum: Hybrid inorganic-organic proton conducting membranes based on nafion, SiO2 and triethylammonium trifluoromethanesulfonate ionic liquid

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