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See detailAtmospheric mercury deposition during the last 1500 years in We Europe: The Misten peat bog record (Hautes Fagnes - Belgium)
Allan, Mohammed ULg; Fagel, Nathalie ULg; De Vleeschouwer, François et al

Poster (2011, April)

The current rate of global atmospheric Hg deposition is approximately three times higher than the preindustrial record and it even increased by a factor of 2-10 in the industrialized regions ... [more ▼]

The current rate of global atmospheric Hg deposition is approximately three times higher than the preindustrial record and it even increased by a factor of 2-10 in the industrialized regions.....()(Hylander and Meili 2003). To determine the extent of such increase, it is necessary to quantify the atmospheric mercury concentration and its temporal variation. For this purpose four 1m Wardenaar peat cores (MIS01W, 04W, 0W5 and 06W) were collected in 2008 in the ombrotrophic Misten bog (Hautes Fagnes Plateau, East Belgium). Mercury was measured using a DMA 80 at the Laboratory of Mechanisms and Transfers in Geology in Toulouse (LMTG, France). The strongest mercury concentrations are measured in the upper half peat record, in a depth interval corresponding to the Industrial Revolution period. Mercury accumulation rate was estimated by applying a coupled 210Pb- 14C age model. The mercury accumulation rate remains relatively small, ranging between 0.9 and 3.3 g.m 2.y 1 during periods corresponding to the decline of Roman Empire and during the Middle Ages. Hg accumulation rate starts to increase when 25 cm, reaching a maximum value (> 115 g.m 2.y 1) at 13.7 cm (i.e.; 1923-1938 AD). Then the values oscillate to reach 9 g.m 2.y 1 at the peat surface (2000-2007AD). In the Misten bog, the evolution of Hg accumulation rate is in agreement with the chronology of other European peat records .......()(Roos-Barraclough et al. 2002). [less ▲]

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See detailAtmospheric metal pollution over the last 250 years inferred from speleothem geochemistry
Allan, Mohammed ULg; Fagel, Nathalie ULg; Verheyden, Sophie

Conference (2015, August 17)

Lead concentrations and isotope ratios from two speleothems from the Han-sur-Lesse cave in southern Belgium were measured in order to study the ability of speleothems to act as archives of atmospheric ... [more ▼]

Lead concentrations and isotope ratios from two speleothems from the Han-sur-Lesse cave in southern Belgium were measured in order to study the ability of speleothems to act as archives of atmospheric pollution. To address this aim we analyzed trace elemental Al and Pb compositions by LA-ICP-MS and ICP-MS as well as Pb isotopes by MC-ICP-MS. The results help to identify three Pb-enriched intervals: from 1880 to 1905 AD, from 1945 to 1965 AD, and from 1975 to 1990 AD. The speleothem record is consistent with the evolution of atmospheric pollution in Belgium. Lead isotope ratios confirm that coal and gasoline combustion, combined with regional metallurgical activities, were the predominant Pb pollution sources in the stalagmites during the last 250 years. This research underscores the importance of speleothems as a valuable tool for the discrimination between anthropogenic and natural lead contributions in the environment and consequently for quantifying the anthropogenic contribution or determining natural background values in continental settings. [less ▲]

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See detailAtmospheric parameters and chemical properties of red giants in the CoRoT asteroseismology fields
Morel, Thierry ULg; Miglio, A.; Lagarde, N. et al

in Astronomy and Astrophysics (2014), 564

A precise characterisation of the red giants in the seismology fields of the CoRoT satellite is a prerequisite for further in-depth seismic modelling. High-resolution FEROS and HARPS spectra were obtained ... [more ▼]

A precise characterisation of the red giants in the seismology fields of the CoRoT satellite is a prerequisite for further in-depth seismic modelling. High-resolution FEROS and HARPS spectra were obtained as part of the ground-based follow-up campaigns for 19 targets holding great asteroseismic potential. These data are used to accurately estimate their fundamental parameters and the abundances of 16 chemical species in a self-consistent manner. Some powerful probes of mixing are investigated (the Li and CNO abundances, as well as the carbon isotopic ratio in a few cases). The information provided by the spectroscopic and seismic data is combined to provide more accurate physical parameters and abundances. The stars in our sample follow the general abundance trends as a function of the metallicity observed in stars of the Galactic disk. After an allowance is made for the chemical evolution of the interstellar medium, the observational signature of internal mixing phenomena is revealed through the detection at the stellar surface of the products of the CN cycle. A contamination by NeNa-cycled material in the most massive stars is also discussed. With the asteroseismic constraints, these data will pave the way for a detailed theoretical investigation of the physical processes responsible for the transport of chemical elements in evolved, low- and intermediate-mass stars. Based on observations collected at La Silla Observatory, ESO (Chile) with the FEROS and HARPS spectrograph at the 2.2 and 3.6-m telescopes under programs LP178.D-0361, LP182.D-0356, and LP185.D-0056.Appendix A is available in electronic form at <A href="http://www.aanda.org/10.1051/0004-6361/201322810/olm">http://www.aanda.org</A>Tables A.2 to A.6 are available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/A119">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/A119</A> [less ▲]

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See detailAtmospheric parameters of 169 F-, G-, K- and M-type stars in the Kepler field
Molenda-Żakowicz, J.; Sousa, S. G.; Frasca, A. et al

in Monthly Notices of the Royal Astronomical Society (2013), 434

The asteroseismic and planetary studies, like all research related to stars, need precise and accurate stellar atmospheric parameters as input. We aim at deriving the effective temperature (T[SUB]eff[/SUB ... [more ▼]

The asteroseismic and planetary studies, like all research related to stars, need precise and accurate stellar atmospheric parameters as input. We aim at deriving the effective temperature (T[SUB]eff[/SUB]), the surface gravity (log g), the metallicity ([Fe/H]), the projected rotational velocity (v sin i) and the MK type for 169 F-, G-, K- and M-type Kepler targets which were observed spectroscopically from the ground with five different instruments. We use two different spectroscopic methods to analyse 189 high-resolution, high-signal-to-noise spectra acquired for the 169 stars. For 67 stars, the spectroscopic atmospheric parameters are derived for the first time. KIC 9693187 and 11179629 are discovered to be double-lined spectroscopic binary systems. The results obtained for those stars for which independent determinations of the atmospheric parameters are available in the literature are used for a comparative analysis. As a result, we show that for solar-type stars the accuracy of present determinations of atmospheric parameters is ±150 K in T[SUB]eff[/SUB], ±0.15 dex in [Fe/H] and ±0.3 dex in log g. Finally, we confirm that the curve-of-growth analysis and the method of spectral synthesis yield systematically different atmospheric parameters when they are applied to stars hotter than 6000 K. [less ▲]

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See detailAtmospheric perturbations on GNSS signals and their influence on time transfer
Warnant, René ULg

in Proceedings of the XXVII URSI General Assembly (2002, August)

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See detailAtmospheric pressure mode localization coupled resonators stiffness sensor
Montaseri, Mohammad; Xie, J.B.; Chang, Homglong et al

in Proceedings of Solid-State Sensors, Actuators and Microsystems (Transducers 2015) (2015, June)

This paper reports on a 3-DoF mode localization resonant sensor experimentally evaluated under atmospheric conditions. It was demonstrated that using amplitude ratio as an output signal, even when the ... [more ▼]

This paper reports on a 3-DoF mode localization resonant sensor experimentally evaluated under atmospheric conditions. It was demonstrated that using amplitude ratio as an output signal, even when the device is operated in air, yields a higher sensitivity compared to the frequency variation sensitivity when assuming vacuum conditions. [less ▲]

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See detailAtmospheric Pressure Plasma as an Activation Step for Improving Protein Adsorption on Hydroxyapatite Powder
Ozhukil Kollath, Vinayaraj ULg; Put, Sofie; Mullens, Steven et al

in Plasma Processes and Polymers (2015)

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See detailAtmospheric Trace Molecule Spectroscopy (ATMOS) experiment version 3 data retrievals
Irion, Fredrick W.; Gunson, Michael R.; Toon, Geoff C. et al

in Applied Optics (2002), 41(33), 6968-6979

Version 3 of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment data set for some 30 trace and minor gas profiles is available. From the IR solar-absorption spectra measured during four Space ... [more ▼]

Version 3 of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment data set for some 30 trace and minor gas profiles is available. From the IR solar-absorption spectra measured during four Space Shuttle missions (in 1985, 1992, 1993, and 1994), profiles from more than 350 occultations were retrieved from the upper troposphere to the lower mesosphere. Previous results were unreliable for tropospheric retrievals, but with a new global-fitting algorithm profiles are reliably returned down to altitudes as low as 6.5 km (clouds permitting) and include notably improved retrievals of H2O, CO, and other species. Results for stratospheric water are more consistent across the ATMOS spectral filters and do not indicate a net consumption of H-2 in the upper stratosphere. A new sulfuric-acid aerosol product is described. An overview of ATMOS Version 3 processing is presented with a discussion of estimated uncertainties. Differences between these Version 3 and previously reported Version 2 ATMOS results are discussed. Retrievals are available at http://atmos.jpl.nasa.gov/atmos. (C) 2002 Optical Society of America. [less ▲]

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See detailThe Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment: Deployment on the ATLAS Space Shuttle missions
Gunson, Michael R.; Abbas, M. M.; Abrams, M. C. et al

in Geophysical Research Letters (1996), 23(17), 2333-2336

The ATMOS Fourier transform spectrometer was flown for a fourth time on the Space Shuttle as part of the ATLAS-3 instrument payload in November 1994. More than 190 sunrise and sunset occultation events ... [more ▼]

The ATMOS Fourier transform spectrometer was flown for a fourth time on the Space Shuttle as part of the ATLAS-3 instrument payload in November 1994. More than 190 sunrise and sunset occultation events provided measurements of more than 30 atmospheric trace gases at latitudes 3-49 degrees N and 65-72 degrees S, including observations both inside and outside the Antarctic polar vortex. The instrument configuration, data retrieval methodology, and mission background are described to place in context analyses of ATMOS data presented in this issue. [less ▲]

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See detailAtmungsmechanik beim Tier. 3. Mitteilung : Methodische und physiologische Aspekte bei der Anwendung des Impuls-Oszilloresistometrie-Systems (IOS)
Reinhold, Petra; Steinbach, Günther; Langenberg, Annelie et al

in Berliner und Munchener Tierarztliche Wochenschrift (1998), 111

The impulse oscillometry system (IOS) which was originally developed for human medicine was found to be suitable for analysing respiratory mechanics in spontaneously breathing animals. This technique is ... [more ▼]

The impulse oscillometry system (IOS) which was originally developed for human medicine was found to be suitable for analysing respiratory mechanics in spontaneously breathing animals. This technique is non-invasive. METHODOLOGICAL ASPECTS: In order to use the IOS-technique in animals, a tightly fitting face mask is necessary. Furthermore, a flexible tube needs to be inserted into the measuring system. While the tube does not influence the measured results significantly, the face mask may affect the measurements. Therefore, its influence on the measured respiratory impedance must be taken into account. To prevent methodological errors, the head and body position of the animal should be standardised during the IOS-measurement. Since the methodological variability of the system is very small, the measuring results are highly reproducible. PHYSIOLOGICAL ASPECTS: In growing subjects, all parameters of respiratory mechanics depend on body weight. Since respiratory physiology is influenced by circadian rhythms, measurements of different days are only comparable when they have been done each day at the same hour. Comparing the respiratory impedance of different animals of similar age and body weight, a considerable inter-individual variability was observed. Due to the low level of physiological intra-individual variability, the method seems to be especially useful for studying influences on the respiratory system (i.e. pharmaceutics, therapeutics) in long-term studies using the same group of subjects. [less ▲]

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See detailAtmungsmechanik beim Tier. 4. Mitteilung : Die diagnostische Aussagefähigkeit von Untersuchungen mit dem Impuls-Oszilloresistometrie-System (IOS) beim Kalb
Reinhold, Petra; Langenberg, Annelie; Lekeux, Pierre ULg

in Berliner und Munchener Tierarztliche Wochenschrift (1998), 111(7-8), 262-267

Taking methodological and physiological aspects into account (see Part 3), the impulse oscillometry system (IOS) was found to be sensitive to detecting and to quantifying clinically relevant changes in ... [more ▼]

Taking methodological and physiological aspects into account (see Part 3), the impulse oscillometry system (IOS) was found to be sensitive to detecting and to quantifying clinically relevant changes in respiratory mechanics in calves. Therefore, the complex respiratory impedance needs to be measured in terms of resistance and reactance within the frequency range between 5 Hz and 20 Hz. The behaviour of resistance and reactance in dependence of frequency allows to differentiate and to localise airway obstructions. Obstructions of upper (extrathoracic) airways were mainly characterised by a frequency independent increase in the resistance. Within the reactance curve, no change in the resonant frequency could be observed. In a peripheral airway obstruction both resistance and reactance changed. The most typical finding concerning resistance was that a negative frequency dependence occurred. The reactance became more negative. Following this, the resonant frequency increased. With progressive obstruction of the peripheral airways, the reactance became more informative than resistance. [less ▲]

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See detailAtolls et récifs du Frasnien du Synclinorium de Dinant (Belgique, France): sédimentologie et implications paléocéanographiques
Boulvain, Frédéric ULg

in Géologie de la France = Geology of France and Surrounding Areas (2006), (1-2), 53-57

The facies architecture, sedimentary dynamics and palaeogeographical evolution were reconstructed for a number of Middle to Late Frasnian buildups developed on a carbonate platform on the south side of ... [more ▼]

The facies architecture, sedimentary dynamics and palaeogeographical evolution were reconstructed for a number of Middle to Late Frasnian buildups developed on a carbonate platform on the south side of the Dinant Synclinorium (Belgium, France). Nine facies were documented in the buildups, each characterized by a specific range of textures and assemblage of organisms. Sedimentological evidence suggests that facies (1) and (2) correspond to iron bacteria-sponge-dominated communities, developing in a quiet aphotic and hypoxic environment. (3) developed between the storm wave base and the fairweather wavebase, in a oligophotic environment. (5), with stromatolitic coatings and thrombolitic bushes developed close to the fairweather wave base. (6) and the fenestral limestone. (7) correspond to an environment with slightly restricted water circulation. (8) developed at subtidal depths in a quiet, lagoonal environment. The main differences between the Middle and Late Frasnian mounds concerns facies architecture and are a consequence of different palaeoceanographic setting. The large flattened Middle Frasnian Arche and Lion buildups show limited vertical differentiation, large-scale progradation features, extensive exportation of material towards off-reef environment and development of inner lagoonal facies. They grew offshore from a well-developed carbonate platform with a healthy carbonate factory. Middle Frasnian sea level fluctuations were relatively mild, and sedimentation was able to counterpart sea-level rise. At the opposite, during Late Frasnian, severe eustatic rises, together with rising oceanic hypoxic conditions were responsible for frequent collapses of the carbonate factory, drowning of the Middle Frasnian carbonate platform and development of buildups with relatively limited lateral extension, high vertical facies differentiation, low potential for material exportation and high content in microaerophilic iron bacteria. [less ▲]

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See detailAtom chip for BEC interferometry
Sewell, R. J.; Dingjan, J.; Baumgärtner, F. et al

in Journal of Physics B (2010), 43(5), 051003

We have fabricated and tested an atom chip that operates as a matter wave interferometer. In this paper we describe the fabrication of the chip by ionbeam milling of gold evaporated onto a silicon ... [more ▼]

We have fabricated and tested an atom chip that operates as a matter wave interferometer. In this paper we describe the fabrication of the chip by ionbeam milling of gold evaporated onto a silicon substrate. We present data on the quality of the wires, on the current density that can be reached in the wires and on the smoothness of the magnetic traps that are formed. We show that the chip is able to operate as an interferometer with good phase stability. [less ▲]

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See detailAtom Transfer Radical Polymerisation (ATRP) and Kharasch addition mediated by titanium-ruthenium bimetallic systems
Richel, Aurore ULg; Delfosse, Sébastien; Demonceau, Albert ULg et al

Poster (2003)

Numerous studies have been directed towards the synthesis of early-late heterobimetallic complexes. Surprisingly, only few reports have been reported about their catalytic behaviour. However, their ... [more ▼]

Numerous studies have been directed towards the synthesis of early-late heterobimetallic complexes. Surprisingly, only few reports have been reported about their catalytic behaviour. However, their potential in homogeneous catalysis is enormous. Indeed, a co-operative work by the two metal centres in the complex may lead to new catalytic systems with unique reactivity. <br /> <br />The Dijon’s team has concentrated their efforts on the synthesis and study of heterobimetallic complexes in which both metal fragments are known for their catalytic activity. Titanocenes are of considerable interest as catalysts for the polymerisation of a-olefins. The catalytic performance of RuCl2(arene) complexes (1) has been demonstrated in different reactions, including olefin metathesis and atom transfer radical polymerisation (ATRP). In attempts to examine such type of catalytic systems, complexation of bent titanocene metallo-ligands by the [RuCl2(p-cymene)]2 dimer is currently investigated. [less ▲]

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See detailAtom transfer radical polymerisation (ATRP) and Kharasch addition mediated by titanium-ruthenium bimetallic systems
Richel, Aurore ULg; Delfosse, Sébastien; Demonceau, Albert ULg et al

Poster (2002, May)

Numerous studies have been directed towards the synthesis of early-Iate heterobimetallic complexes. Surprisingly, only few reports have been reported about their catalytic behaviour. However, their ... [more ▼]

Numerous studies have been directed towards the synthesis of early-Iate heterobimetallic complexes. Surprisingly, only few reports have been reported about their catalytic behaviour. However, their potential in homogeneous catalysis remains fantastic. Indeed, a cooperative work by the two metal centres in the complex would lead to new catalytic systems with unique reactivity. [less ▲]

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See detailAtom transfer radical polymerization of MMA with a macromolecular ligand in a fluorinated solvent and in supercritical carbon dioxide
Grignard, Bruno ULg; Jérôme, Christine ULg; Calberg, Cédric ULg et al

in European Polymer Journal (2008), 44(3), 861-871

Macromolecular fluorinated ligands were prepared according to a three-step strategy that consists of the random copolymerization of heptadecafluorodecyl acrylate and 2-hydroxyethylacrylate, followed by ... [more ▼]

Macromolecular fluorinated ligands were prepared according to a three-step strategy that consists of the random copolymerization of heptadecafluorodecyl acrylate and 2-hydroxyethylacrylate, followed by the esterification of the pendant hydroxyl groups with acryloyl chloride and the Michael-type addition of tetraethyldiethylenetriamine onto the acrylic double bonds of the polymeric chains. These fluorinated macroligands were successfully used in the atom transfer radical polymerization of MMA catalyzed by a copper salt in a fluorinated solvent. The polymerization control was analyzed in relation to the copper salt, the initiator and the molecular weight and composition of the macroligand before being extended to the heterogeneous ATRP of MMA in scCO2. [less ▲]

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See detailAtom-transfer radical polymerization of vinyl monomers mediated by stable ruthenium-carbene complexes.
Demonceau, Albert ULg; Simal, François; Delaude, Lionel ULg et al

in Abstracts of Papers - American Chemical Society, National Meeting (1999), 218(Part 2), 289-

We reported on the exceptional efficacy of new catalytic systems based on well-defined and fully characterized [RuCl2(p-cymene)(PR3)] complexes (p-cymene = 4-isopropyltoluene) to promote the controlled ... [more ▼]

We reported on the exceptional efficacy of new catalytic systems based on well-defined and fully characterized [RuCl2(p-cymene)(PR3)] complexes (p-cymene = 4-isopropyltoluene) to promote the controlled free-radical polymerization of vinyl monomers without cocatalyst activation. It appeared that only phosphines which are both strongly basic and which possess a well-defined steric bulk presented both high catalytic activity and high control of the polymerization process. The most suitable phosphines were triisopropylphosphine and tricyclohexylphosphine (PCy3, Cy = cyclohexyl). Surprisingly, the best catalyst systems for ATRP were also the most active ones for the ring-opening metathesis polymerization (ROMP) of cycloolefins. With this in mind, [RuCl2(=CHPh)(PCy3)2], the Grubbs' ruthenium-carbene complex commonly used for olefin metathesis, was tested and found to be also highly efficient for ATRP. In this paper, we present some studies on the scope and limitations of stable ruthenium-carbene complexes as potential catalysts for the ATRP of vinyl monomers. [less ▲]

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