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Goransson G.,Swedish Geotechnical Institute | Larson M.,Lund University | Althage J.,DHI Water - Environment - Health
Journal of Waterway, Port, Coastal and Ocean Engineering | Year: 2014

Ship-generated waves were investigated in the Göta älv river, which is a major waterway on the Swedish west coast between the sea and Lake Vänern. Ships with a typical size of 85×15×5m(length×width×draft) travel at speeds between 5 and 10 knots, generating waves that cause sediment transport and erosion along the river bed and banks. Field measurements of the wave properties and turbidity were carried out during 17 ship passages, and comparisons were made with the most commonly used formulas for predicting ship waves. The formula proposed by the Permanent International Association of Navigation Congresses yielded the overall best agreement for the divergent (secondary) waves, whereas the drawdown (primary wave) could best be estimated from the vessel sinkage. The maximum recorded turbidity was mainly a function of the drawdown, and it could be well predicted from the parameterized bed shear stress. In conclusion, ship waves often induce bed and bank erosion in restricted waterways and, although simplistic formulas involve significant uncertainties, they are still useful tools for predictions. However, more studies are needed to determine the influence of a limited river cross section on the wave generation and the relationship between ship waves and sediment transport. © 2014 American Society of Civil Engineers. Source

Sjostedt C.,KTH Royal Institute of Technology | Persson I.,Swedish University of Agricultural Sciences | Hesterberg D.,North Carolina State University | Kleja D.B.,Swedish Geotechnical Institute | And 2 more authors.
Geochimica et Cosmochimica Acta | Year: 2013

Complexation of iron by organic matter can potentially compete with toxic metals for binding sites. Iron(III) forms both monomeric and di/trimeric complexes with fulvic and humic acids, but the nature and extent of complexation with natural organic matter samples from soft-water lakes has not been extensively studied. The aim of this study was to determine the coordination of iron in complexes with organic matter in two soft-water lakes and in the surrounding Oe soil horizons. Iron K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy was performed on particles and large colloids (>0.45. μm) collected by in-line pre-filtration, and on smaller colloids isolated both on an AGMP-1 anion-exchange column and by concentration using 1000. Da ultrafiltration. The results showed that iron(III) was mainly present in monomeric complexes with organic matter, both in the lake water smaller colloids and in the soil samples. Evidence for iron(III) (hydr)oxides was found for the lake particles, in the ultrafiltration retentates, and in some of the soils. Overall, the results suggest that complexation of iron(III) to organic matter prevents hydrolysis into polymeric forms. Strong complexation of iron(III) would lead to competition with other metals for organic-matter binding sites. © 2012 Elsevier Ltd. Source

Von Hagke C.,Helmholtz Center Potsdam | Von Hagke C.,California Institute of Technology | Cederbom C.E.,Swedish Geotechnical Institute | Oncken O.,Helmholtz Center Potsdam | And 3 more authors.
Tectonics | Year: 2012

The evolution of the Central Alpine deformation front (Subalpine Molasse) and its undeformed foreland is recently debated because of their role for deciphering the late orogenic evolution of the Alps. Its latest exhumation history is poorly understood due to the lack of late Miocene to Pliocene sediments. We constrain the late Miocene to Pliocene history of this transitional zone with apatite fission track and (U-Th)/He data. We used laser ablation inductively coupled mass spectrometry for apatite fission track dating and compare this method with previously published and unpublished external detector method fission track data. Two investigated sections across tectonic slices show that the Subalpine Molasse was tectonically active after the onset of folding of the Jura Mountains. This is much younger than hitherto assumed. Thrusting occurred at 10, 8, 6-5Ma and potentially thereafter. This is contemporaneous with reported exhumation of the External Crystalline Massifs in the central Alps. The Jura Mountains and the Subalpine Molasse used the same detachments as the External Crystalline Massifs and are therefore kinematically coupled. Estimates on the amount of shortening and thrust displacement corroborate this idea. We argue that the tectonic signal is related to active shortening during the late stage of orogenesis. © 2012. American Geophysical Union. All Rights Reserved. Source

Xu J.,Lulea University of Technology | Kleja D.B.,Swedish Geotechnical Institute | Biester H.,TU Braunschweig | Lagerkvist A.,Lulea University of Technology | Kumpiene J.,Lulea University of Technology
Chemosphere | Year: 2014

Feasibility of soil washing to remediate Hg contaminated soil was studied. Dry sieving was performed to evaluate Hg distribution in soil particle size fractions. The influence of dissolved organic matter and chlorides on Hg dissolution was assessed by batch leaching tests. Mercury mobilization in the pH range of 3-11 was studied by pH-static titration. Results showed infeasibility of physical separation via dry sieving, as the least contaminated fraction exceeded the Swedish generic guideline value for Hg in soils. Soluble Hg did not correlate with dissolved organic carbon in the water leachate. The highest Hg dissolution was achieved at pH 5 and 11, reaching up to 0.3% of the total Hg. The pH adjustment was therefore not sufficient for the Hg removal to acceptable levels. Chlorides did not facilitate Hg mobilization under acidic pH either. Mercury was firmly bound in the studied soil thus soil washing might be insufficient method to treat the studied soil. © 2014 The Authors. Source

Bjurstrom H.,AF Industry AB | Lind B.B.,Swedish Geotechnical Institute | Lagerkvist A.,Lulea University of Technology
Fuel | Year: 2014

Unburned carbon (UC) in 21 combustion residues from solid biofuels has been examined using several methods of analysis (including LOI and TOC) as well as micro-Raman spectroscopy. The concentration of unburned carbon in the residues varied over an order of magnitude and in several samples accounted for about 10% of the ash mass. It was observed that TOC had a poor correlation to organic carbon, especially for fly ashes. LOI at all tested temperatures showed a better correlation than TOC to the organic carbon content, whereas the TOC is better correlated to elemental carbon. LOI550 gave a larger variation and a less complete mobilisation of unburned carbon than LOI at 750 or 975 C did, but at the highest temperature metal oxidation was notably affecting the mass balance to the extent that some samples gained mass. For this reason, and of the temperatures tested, LOI750 seem to be the most stable indicator for organic remains in the incineration residuals. Most of the unburned carbon is elemental, and only slowly degradable, so the potential emissions of organic compounds from ashes should not be assessed by using a TOC test. The structure of the detected elemental carbon in UC is similar to that of activated carbon, which indicates a potentially large specific surface. This should be borne in mind when assessing the environmental impact of using ash for different purposes, including use as a construction material. Field studies are needed to verify the actual impact as it may depend on environmental conditions. © 2013 Elsevier Ltd. All rights reserved. Source

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