Abstract: The present work focuses on the use of micro-analytical techniques to demonstrate the heterogeneous distribution of radionuclides and metals in soils collected at Former Soviet Union mining sites in Central Asia. Based on digital autoradiography, radionuclides were heterogeneously distributed in soil samples collected at the abandoned uranium mining sites Kurday, Kazakhstan, Kadji Sai, Kyrgyzstan and Taboshar, Tajikistan. Using electron microscopy interfaced with X-ray microanalysis submicron – mm-sized radioactive particles and rock fragments with U, As, Se and toxic metals on the surfaces were identified in Kurday and Kadji Sai samples. Employing scanning and tomographic (3D) synchrotron radiation based micro-X-ray fluorescence (mu-SRXRF) and synchrotron radiation based micro-X-ray diffraction (mu-SRXRD) allowed us to observe the inner structure of the particles without physical sectioning. The distribution of elements in virtual crosssections demonstrated that U and a series of toxic elements were rather heterogeneously distributed also within individual radioactive TENORM particles. Compared to archived data, U in Kadji Sai particles was present as uraninite (U4O9+y or UO2+x) or Na-zippeite aNa(4)(UO2)(6)[(OH)(10)(SO4)(3)]center dot 4H(2)O), i.e. U minerals with very low solubility. The results suggested that TENORM particles can carry substantial amount of radioactivity, which can be subject to re-suspension, atmospheric transport and water transport. Thus, the potential radioecological and radioanalytical impact of radioactive particles at NORM and TENORM sites worldwide should be taken into account. The present work also demonstrates that radioecological studies should benefit from the use of advanced methods such as synchrotron radiation based techniques. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract: The present contribution reviews some recent electron microscopy investigations on different shape memory systems in which a variety of nano- and micro-defect structures play an essential role in the functional behaviour of the material. (NiTi3)-Ti-4 precipitates in Ni-Ti are a well-known example for which the focus is now on the 3D configurations, in Ni-Ti-Nb Nb-rich nanoprecipitates are thought to have a large impact on the hysteresis, in Co-Ni-Al an Al-enriched zone nearby the y'-precipitates yields a small sandwiched austenite while some first signs of quasidynamical lattice deformation in non-frozen Ni-Ti strain glass are measured by Cs-aberration-corrected transmission electron microscopy. (C) 2011 Elsevier B.V. All rights reserved.

Abstract: The combination of a non-thermal plasma with catalysis is considered as a sustainable indoor air purification technology to achieve complete oxidation at reduced energy cost with a longer electrode lifetime. An optimal window of operation for plasma assisted catalysis is found by varying the polarity, the applied voltage, the relative humidity of the gas phase and the configuration of the plasma reactor. The results show that, in general, negative corona discharge can obtain higher nitric oxide (NO) conversion efficiencies compared to positive corona. It is also clear that at higher applied voltages, higher conversion efficiency can be reached. The effect of relative humidity, however, is not found to be significant in the range (0 20.3 %) tested in this work. Additionally, the configuration of the plasma reactor is changed by varying the amount of pins that are attached at the collector electrode. The results show that there is an optimum at 10 pairs of pins to obtain a high conversion efficiency of NO. By applying a coating on the collector electrode of the plasma reactor, it is possible to see the influence of the coating on the performance of the plasma system, which was operating in the previously found optimal window. It stands clear that the use of a plasma assisted catalysis system has high potential as an integrated and sustainable indoor air purification technology.