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| Roekens, E.J.; Van Grieken, R.E.. |
| The rate of iron(II) oxidation in the North Sea water of pH 5.5-10 in the range 10-25°C has been studied. The oxygenation rate depends linearly on the iron(II) and dissolved oxygen concentrations. The second-order dependence on (OH<sup>-</sup>), found by several investigators for synthetic solutions, was confirmed in seawater, but only for pOH>6.9. For pOH<5.9 the rate appeared to be independent of the pOH. In the intermediate range, pOH<5.9-6.9, corresponding to the natural pH of seawater, a first-order dependence on the pOH is obeyed. The important discrepancy in the literature between the second-order rate constant for NaCHO<sub>3</sub> solutions and for seawater can be attributed predominantly to the incorrect... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Iron; Kinetics; Oxidation. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3293 |
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| Bernard, P.C.; Van Grieken, R.E.. |
| The suspended particulate matter from a series of stations in an estuary is automatically analyzed for 11 elements on a particle-by-particle basis by using electron microprobe X-ray microanalysis and an automatic image analysis system. The interpretation of the large acquired data set implies numerical multivariate analysis. The developed procedure consists of using cluster analysis on the particles of individual samples, followed by nearest centroid sorting over all samples from the study area. For the Ems estuary, the procedure provided 13 geochemically different particle types of which the relative abundance through the estuary could be followed and interpreted in terms of estuarine mixing processes. The presented methodology could be applied in other... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Estuarine chemistry; Multivariate analysis; Suspended particulate matter. |
| Ano: 1986 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3219 |
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| Rojas, C.M.; Injuk, J.; Van Grieken, R.E.; Maenhaut, W.. |
| Over a period of eight months, a total of 26 atmospheric particulate matter samples were collected at the location of Tahiti and in other areas of French Polynesia, using a specially equipped sailboat. A 6-stage cascade impact or was used to separate aerosols in the following size classes: > 4,2-4, 1-2,0.5-1,0.25-0.5 and < 0.25 µm equivalent aerodynamic diameter. The resulting set of 156 size segregated aerosol samples was analyzed by particle-induced X-ray emission for 16 elements. This study deals with the concentrations of Na, Mg, Al, Si, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Sr and Pb. Enrichment factor calculations reveal that Na, Mg, S, A, K, Ca and Sr were little fractionated with respect to bulk sea water, whereas Al, Si, Ti, Mn and Fe... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aerosols Heavy metals Multivariate analysis Sedimentary environments ISE; French Polynesia. |
| Ano: 2000 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7134 |
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| Johansson, T.B.; Van Grieken, R.E.; Winchester, J.W.. |
| Biased data set averaging has been used to examine aerosol elemental composition data for air mass directional effects. Samples collected in north Florida during spring and summer 1973 were influenced by local and remote continental sources and additionally by maritime sources when air flow was southerly. Judgments of air movements during the collection of 32 5-stage cascade impactor samples were made by examination of daily surface weather maps, 3-hourly surface winds in Tallahassee, and semi-diurnal balloon soundings to 1,524 meters. Averages of elemental abundances as a function of particle size, determined by proton-induced X-ray emission, PIXE, were computed for a 14-sample set biased towards continental air flow, excluding 12 additional samples where... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1974 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3508 |
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| Van Grieken, R.E.; Johansson, T.B.; Winchester, J.W.. |
| Laboratory experiments were performed using radioactive tracers of <sup>65</sup>Zn, <sup>75</sup>Se, <sup>22</sup>Na, <sup>137</sup>Cs and <sup>152</sup>Eu added to natural sea water to determine differences in elemental composition between sea water and aerosol droplets as a function of particle size. The experiments were conducted using a flow of air as a stream of bubbles rising and bursting at the surface of a vessel containing sea water with added radioactive tracers at pH 8. The resultant aerosol cloud was drawn through a cascade impactor which separated particle size fractions for analysis. In a typical experiment 30 ml of sea water, collected in polyethylene no more than a few hours before... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1974 |
URL: http://www.vliz.be/imisdocs/publications/262479.pdf |
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| Noone, K.J.; Öström, E.; Ferek, R.J.; Garrett, T.; Hobbs, P.V.; Johnson, D.W.; Taylor, J.P.; Russell, L.M.; Flagan, R.C.; Seinfeld, J.H.; O'Dowd, C.D.; Smith, M.H.; Durkee, P.A.; Nielsen, K.; Hudson, J.G.; Pockalny, R.A.; De Bock, L.; Van Grieken, R.E.; Gasparovic, R.F.; Brooks, I.. |
| The effects of anthropogenic particulate emissions from ships on the radiative, microphysical, and chemical properties of m(oderately polluted marine stratiform clouds are examined. A case study of two ships in the same air mass is presented where one of the vessels caused a discernible ship track while the other did not. <i>In situ</i> measurements of cloud droplet size distributions, liquid water content, and cloud radiative properties, as well as aerosol size distributions (outside cloud, interstitial, and cloud droplet residual particles) and aerosol chemistry, are presented. These are related to measurements of cloud radiative properties. The differences between the aerosol in the two ship plumes are discussed; these indicate that... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aerosols; Air pollution; Albedo; Anthropogenic factors; Atmospheric boundary layer; Atmospheric particulates; Chemical plumes; Cloud physics; Clouds; Droplets; Fuels; Ocean-atmosphere system; Pollution effects; Radiative transfer; Ships; Size distribution. |
| Ano: 2000 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8840 |
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