10 research outputs found

    INVESTIGATION OF THE VOLATILISATION OF RECOIL PRODUCTS FROM IONIC CRYSTALS

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    Des matĂ©riaux polycristallins furent dotĂ©s des produits de recul provenant de la fission de l'uranium-235 par des neutrons. La volatilisation de Xe, I, Tc et Te fut examinĂ©e par des expĂ©riences isothermes et non isothermes, et le phĂ©nomĂšne de dĂ©gagement est discutĂ©. Les courbes isothermes peuvent ĂȘtre approchĂ©es par une fonction traçant une rĂ©action du 2e genre ou de pseudo-2e genre. Les donnĂ©es Tmax, qui peuvent ĂȘtre dĂ©rivĂ©es du thermogramme, dĂ©pendent du degrĂ© du chauffage, de la composition du courant de gaz et sont fortement influencĂ©es par les matĂ©riaux ioniques mis en Ɠuvre comme matiĂšre rĂ©ceptrice. Ces effets sont discutĂ©s phĂ©nomĂ©nologiquement.Polycrystalline materials were doped with recoil products formed in 235U (n,f)- reactions. In isothermal and non isothermal experiments the volatilisation of Xe, I, Tc and Te was examined and the release phenomena are discussed. The isothermals can be approached mathematically by a function which describes a 2nd order or a pseudo 2nd order reaction. The Tmax values, which can be derived from the thermograms, depend on the heating rate, the composition of the streaming gas, and are strongly influenced by the ionic matrices used as stopping materials. These effects are discussed phenomenologicall

    Influence of ashing temperature on plutonium separation from bones

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    The EU network on trace element speciation in full swing

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    cited By 8International audienceThe EC-funded thematic network 'Speciation 21' links scientists in analytical chemistry working in method development for the chemical speciation of trace elements, and potential users from industry and representatives of legislative agencies, in the field of environment, food and occupational health and hygiene. The network covers a number of important issues including organotin compounds, chromium and nickel species, chemical characterisation of environmental and industrial particulate samples, risk assessment, selenium and a series of other essential and toxic elements in food, as well as the influence of packing materials. Once the analytical methodology for the measurement of the trace element species has been optimised, the importance of trace element speciation will grow enormously. Food sciences, material sciences, medicine and occupational health, environmental sciences and related fields will all profit. The network will also substantially promote the dissemination of knowledge through the member states. (C)2000 Elsevier Science B.V
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