Using 222 Rn for hydrograph separationin a micro basin (Luxembourg)

In order to obtain information on the hydrological signature of rivers during and after heavy rain events, small catchment areas are selected as experimental sites. Hydrograph separations based on environmental tracers are performed. Natural isotopic tracers such as 18O, 2H and particularly 222Rn may help to distinguish the components dominating the outflow, particularly of 'pre-event waters', 'event waters' and 'post-event waters'. Even with moderate concentrations in groundwater, radon can be a very sensitive indicator of groundwater input into rivers. The selected microbasin under investigation is situated in the western part of Luxembourg and belongs to the Attert River catchment. At chosen points at the basin's outflow radon detectors continuously measure radon activity in water. The radon monitors are installed together with high precision thermometers, conductivity meters, flow meters and automatic water samplers for chemical analysis. Besides the continuous measurements, grab water samples are taken at different locations along the stream, most of them during periods of heavy rain events. Presented are the results of a one year measurement campaign. During the dry season i.e. during more or less continuous discharge conditions, the observed mean values do not show substantial variations and can be used as reference values. Fluctuations of the measured data during rain events are discussed and the interplay between the different parameters analysed

Comparative study of nano-ZSM-5 catalysts synthesized in OH- and F- media

This study reports the seeded synthesis of MFI-type (ZSM-5) zeolite in fluoride medium at pH = 8.5. Crystal growth kinetics of the resulting zeolite (ZSM-5-F) as a function of seed content and crystallization temperature is studied. The crystallization time is reduced to 1.5 h and crystals with sizes below 200 nm and a Si/Al ratio of 23.6 are obtained. A zeolite with similar characteristics but synthesized in a hydroxyl medium (ZSM-5-OH) is used to evaluate ZSM-5s synthesized in different crystallization media. Their physicochemical properties are compared and particular attention is paid to the nature, number, and distribution of silanol sites. The two zeolites exhibit similar number of Brφnsted acid sites; however the material synthesized in a hydroxyl medium contains a substantially larger number of surface and internal silanols that impact significantly its catalytic performance in methanol to hydrocarbon transformation. While the two materials exhibit similar selectivity in methanol transformations, the catalyst synthesized in fluoride medium shows superior activity and resistance to deactivation. The results suggest that seeded synthesis in a fluoride medium can be used for the preparation of superior zeolite catalysts

Titanium silicalite-1 macrostructures for photocatalytic removal of organic pollutants from aqueous media

Titanium silicalite-1 (TS-1) structures in the form of macroscopic beads with hierarchical porosity were prepared by the resin templating method. The Ti content within the samples was varied between 1 and 7 wt%, with corresponding surface areas ranging from 725 to 350 m2 g−1, respectively. The samples contained a large amount of amorphous material, which was necessary to achieve high mechanical stability of the beads. The TS-1 macrostructures were used as catalysts for the photocatalytic degradation of methylene blue (MB), and results were compared to the results for a commercial anatase nanopowder (CristalACTiV™ PC500). All TS-1 beads showed similar MB degradation rates independently of their Ti content, which was linked to variations in the surface areas and structure. The macroscopic shape of the TS-1 beads allowed easy recovery from the mother liquor upon decolouration of the MB solutions, which was highly beneficial compared to the reference anatase nanopowder. The TS-1 beads could be reused in subsequent photocatalytic cycles after decanting exhausted solutions and replacing with fresh MB solutions without any energy-consuming regeneration steps involved. The samples were tested in five consecutive cycles and MB degradation rates remained broadly unchanged during all tests

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

Radon in potable waters in Luxembourg

The presence of elevated concentrations of radon in water is a potential health risk when the water is used in public water supply, mainly because of the increase of radon concentration in the indoor air due to degassing [16]. Samples were taken from a large number of Luxembourg’s drinking water springs in 2007 to determine the major ion chemistry and potential contaminants, mainly from agriculture. The natural radioactive isotopes were analysed as part of this program. Two sampling campaigns were performed, one in summer, one in winter, to consider seasonal variations. This paper presents the radon activities, which were sampled during the two field campaigns and measured using liquid scintillation counting (LSC). For quality assurance of our results we made three replicates from each collected water sample. This methodology was used because it is more accurate than other possible methods of radon measurement, and its limit of detection is sufficiently low, i.e., 700 Bqźm–3. The correlation between radon and radium levels was estimated, as well as the dependence of radon levels on geology. The results from the year 2007 were compared to previous measurements from the year 2003. Five springs in the program were sampled monthly throughout a year to account for possible seasonal variations, additionally to the large spatial extend of the program

Influence of variable stress on underground radon concentrations

Los esfuerzos aplicados a las rocas de la corteza generan deformaciones locales. Para medir una señal de radón debida a esfuerzos variables y tensión en la roca, se utilizó un laboratorio natural bajo un tanque de almacenamiento de la planta de energía de Vianden (Luxemburgo). Dependiendo de las demandas de energía, los tanques artificiales que se encuentran en lo alto de una colina sufren fluctuaciones diarias de hasta 16 metros en los niveles del agua y ejercen presiones variables en las rocas donde están asentados. Las concentraciones de radón se miden continuamente en pozos cavados en la roca debajo de los tanques. Se observan algunas variaciones importantes en las concentraciones transitorias de radón inducidas por las fluctuaciones de los niveles del agua. El tanque está compuesto por dos tanques independientes que se vaciaron durante cierto periodo de tiempo. El patrón de comportamiento del radón depende de la localización de los pozos de medida bajo el tanque y es distinto si los dos tanques trabajan simultáneamente, o si uno de los tanques está vacío. Los patrones observados pueden explicarse considerando caminos variables de los fluidos, sobrepresión del fluido y por el flujo dinámico en las fracturas. doi: https://doi.org/10.22201/igeof.00167169p.2002.41.3.35

Spatial distribution investigation of radioactivity of potable waters in Luxembourg

A survey of naturally occurring radio-nuclides was performed on the territory of Luxembourg in order to identify the main physical and chemical parameters in drinking waters. During last summer water samples from 316 different outflows were collected twice and analyzed. A routine laboratory sequentional extraction radiochemistry procedure was applied for monitoring low concentrations of radio-nuclides in natural waters. New investigations were done to optimize some analysis conditions for the different determination procedures. A quality assurance procedure was applied. The obtained results are analyzed in term of spatial distribution, supported geology and chemistry

Proinflammatory Cytokine Polymorphisms and Severity of Periodontitis in a Cohort of Bulgarian Patients

In this manuscript we are discussing our research of the presence of single nucleotide polymorphisms (SNPs) of two proinflammatory cytokines – interleukin 17F (IF-17F) and interleukin 23 (IL-23) in a cohort of Bulgarian patients