| 1. |
- Dahlqvist, Ralf, et al.
(författare)
-
Temporal variations of colloidal carrier phases and associated trace elements in a boreal river
- 2007
-
Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 71:22, s. 5339-5354
-
Tidskriftsartikel (refereegranskat)abstract
- Elemental size distributions, from truly dissolved through colloidal to particulate, have been studied in a subarctic boreal river. The measurements, carried out during 2002, ranged from winter to summer conditions, including an intense spring flood event. Results are reported for a total of 42 elements. Size distributions were characterised using a combination of cross-flow (ultra)filtration (CFF), flow field-flow fractionation (FIFFF), and diffusive gradients in thin-films (DGT). The three techniques showed similar trends, but quantitative comparisons reveal some important differences that warrant further investigation. Previous work has identified two colloidal carrier phases in fresh waters, dominated by iron and carbon, respectively. The majority of the elements studied are associated with one or both of these colloidal carrier phases. The exceptions are the alkali metals and several anions that are only very weakly associated with colloidal material, and which therefore occur mainly as truly dissolved material (< 1 kDa in molecular weight). We discuss the likely origin for the two colloidal carrier phases and consider how associated trace elements fit into the geochemical framework. The relative affinities of the elements for iron and carbon colloidal carrier phases are related to their chemistries, and are compared with earlier data from the Delsjo Creek in southern Sweden. Elemental colloidal concentrations show strong seasonal variations related to changes in the colloidal carrier phase(s) with which they associate. In particular, many elements show a strong spring maximum in colloidal concentrations associated with the strong maximum in colloidal carbon concentration during the spring flood.
|
|
| 2. |
- Gustafsson, Magnus
(författare)
-
Diatom-diatom interactions with light : Applications and line shape theoretical aspects
- 2008
-
Ingår i: Spectral line shapes, volume 15. - Melville, NY : American Institute of Physics (AIP). - 9780735405882 ; 15, s. 297-301
-
Konferensbidrag (refereegranskat)abstract
- Recent advances in calculations of collision-induced absorption- and Raman-spectra in pure diatomic gases are presented. An extensive calculation of H2-H2 absorption from 40 K to 400 K has provided improved understanding of the atmosphere of Uranus. A highly advanced close-coupling calculation of H2-H2 light scattering has verified that the line shapes are affected by interference between the permanent H2 and the H2-H2 interaction-induced polarizabilities. A few directions that the research in astrophysical applications of collision-induced absorption is taking are also described. For instance, H2-H 2 dipole and potential surfaces for vibrations higher than v = 1 are currently being developed to enable simulations of collision-induced absorption at temperatures relevant for white dwarf atmospheres. For low temperature N 2-N2 absorption there is unresolved discrepancy between measurement and simulation. A possible solution to this puzzle is suggested
|
|
| 3. |
|
|
| 4. |
- Morin, Dominique, et al.
(författare)
-
BioMinE : integrated project for the development of biotechnology for metal-bearing materials in Europe
- 2006
-
Ingår i: Hydrometallurgy. - : Elsevier. - 0304-386X .- 1879-1158. ; 83:1-4, s. 69-76
-
Tidskriftsartikel (refereegranskat)abstract
- Biohydrometallurgy is the offspring of the unexpected union of biotechnology and metallurgy. From specific properties of some extreme biotopes, active principles of interactions between microbial metabolisms and minerals have been extracted to be used as efficient metallurgical processes.Many profitable industrial operations based on these bioprocesses have been running to recover copper, gold, uranium or cobalt for instance and many other applications have been designed.Europe was quite active in this area in the past, but currently the leadership is in South Africa, America and Australia.BioMinE (Biotechnology for Metal-bearing material In Europe) is a large integrated project launched with the support of the European Commission. It is aimed at stimulating synergies between the most relevant universities, research and industrial organisations to develop new concepts in this technical field that allow a better exploitation of the mineral resources in the future.The main technical subject is the investigation of the opportunities to apply bioleach processes to primary and secondary resources of metal-bearing materials. The second technical area of the project in terms of effort is the study of the recovery of metals from pregnant bioleach solution using biological reagents. All along the project duration, these investigations are focussed on the relevant resources in Europe screened according to an iterative process. The integration of the innovative pathways of processing will be evaluated up to the pilot scale whenever it is appropriate.The Consortium of BioMinE comprises 35 partners from industry (12 including 5 SMEs) research organisations (9) universities (14) and government (2). The participants are from 12 EU member states, from 1 candidate country (Romania), and from South Africa (INCO Country).The overall budget of the project is 17.9 million Euros, with a contribution from the European Commission of 11.6 million Euros. Started on November 1, 2004, the project will last 4 years.An overview of BioMinE in the general context of the biohydrometallurgy development is the subject of this presentation.
|
|
| 5. |
- Morin, Dominique, et al.
(författare)
-
Progress after three years of BioMinE-Research and Technological Development project for a global assessment of biohydrometallurgical processes applied to European non-ferrous metal resources
- 2008
-
Ingår i: Hydrometallurgy. - : Elsevier. - 0304-386X .- 1879-1158. ; 94:1-4, s. 58-68
-
Tidskriftsartikel (refereegranskat)abstract
- BioMinE is an integrated project under the sixth framework programme of research supported by the European Commission, which started in November 2004 and will last until October 2008 (Ref. NMP2-CT-2005-500329). It is dedicated to the evaluation of biohydrometallurgy to improve the exploitation of the European non-ferrous metal resources in a sustainable way. At the end of 2007, the Consortium of BioMinE comprised 37 partners from industry (13 including 6 Small or Medium Enterprises), research organisations (8), universities (15), and government (1). The participants are from 13 EU member states and from Serbia and South Africa (INCO Countries). For more details see http://biomine.brgm.fr.The three main kinds of resources considered for bioleaching studies are:- Copper polymetallics (concentrates and tailings),- Zinc polymetallics (zinc and zinc polymetallic concentrates)- Secondary wastes (tailings, rock and metallurgical wastes, etc.)For each of these resources, amenability studies of application of bioleaching technologies by various approaches have been undertaken or still ongoing. Further processing assessment will be conducted up to the demonstration scale. Technological improvements have been made to apply bioleaching in the context of the European resources in terms of complexity and sustainability requirements. The relevant fundamental studies covering bio-prospecting, molecular ecology, biochemistry, and genetics areas aimed at improving the understanding and the control of the selected technologies have given original results.Much progress has also been obtained in the use of the microbial sulfate-reducing process to polish effluents and to recover metals from leachates containing low concentrations of metals. The finding of micro-organisms thriving at low and high temperature, respectively 8 and 65 °C, leads to an extension of the application range of the process. It has been also observed that this process could be pushed down to pH 4.5 and 4 creating opportunities of selective metal recovery as metal sulphides. It has also been demonstrated that sulphate can be removed at high concentrations, as well as arsenic or selenium. The next step in this work is pilot testing. This will allow to determine scale-up criteria and to assess the residual metal concentration under actual conditions.The pilot-scale demonstration operations, as well as the techno-economic and comparative sustainability assessments will be achieved during 2008, the last year of the project.The prototypes of the learning objects for training about biohydrometallurgy accessible by internet have been elaborated. A public output of this work is accessible at http://wiki.biomine.skelleftea.se/wiki. The basic knowledge thus delivered is aimed at disseminating the understanding of the origins and use of biohydrometallurgy.Contacts with mining operators in Europe have been taken and collaboration schemes have been established in various ways according to the respective contexts. When a high potential of technical involvement could be foreseen, a direct participation of the mining operators in the project was favoured, this led to integrate KGHM (Pol), Boliden (Sw) and Copper Institute of Bor (Serbia) into the consortium of partners.When no direct technical commitment was conceivable at the first stage, collaboration was established with companies with the most urgent requirement to have access to the relevant resource.
|
|
| 6. |
- Boström, Dan, 1954-, et al.
(författare)
-
Ash transformations in fluidized-bed combustion of rapeseed meal
- 2009
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 23:5, s. 2700-2706
-
Tidskriftsartikel (refereegranskat)abstract
- The global production of rapeoil is increasing. A byproduct is rapeseed meal that is a result of the oil extraction process. Presently the rapeseed meal mainly is utilized as animal feed. An interesting alternative use is, however, energy conversion by combustion. This study was undertaken to determine the combustion properties of rapeseed meal and bark mixtures in a bubbling fluidized bed, with emphasis on gas emissions, ash formation, -fractionation and -interaction with the bed material. Due to the high content of phosphorus in rapeseed meal the fuel ash is dominated by phosphates, in contrast to most woody biomass where the ash is dominated by silicates. From a fluidized bed combustion (FBC) point of view, rapeseed meal could be a suitable fuel. Considering FBC agglomeration effects, pure rapeseed meal is in level with the most suitable fuels, as earlier tested by the methods utilized in the present investigation. The SO2 emission, however, is higher than most woody biomass fuels as a direct consequence of the high levels of sulfur in the fuel. Also the particulate matter emission, both submicron and coarser particles, is higher. Again this can be attributed the high ash content of rapeseed meal. The high abundance of SO2 is apparently effective for sulfatization of KCl in the flue gas. Practically no KCl was observed in the particulate matter of the flue gas. A striking difference in the mechanisms of bed agglomeration for rapeseed meal compared to woody biomass fuels was also observed. The ubiquitous continuous layers on the bed grains found in FBC combustion of woody biomass fuels was not observed in the present investigation. Instead very thin and discontinuous layers were observed together with isolated partly melted bed ash particles. The latter could occasionally be seen as adhered to the quartz bed grains. Apparently the bed agglomeration mechanism, that obviously demanded rather high temperatures, involved more of adhesion by partly melted ash derived potassium-calcium phosphate bed ash particles/droplets than direct attack of gaseous alkali on the quartz bed grains forming potassium-calcium silicate rich bed grain layers. An explanation could be found in the considerable higher affinity for base cations of phosphorus than silicon. This will to a great extent withdraw the present basic oxides from attacking the quartz bed grains with agglomeration at low temperatures as a result.
|
|
| 7. |
- Holmberg, Hans-Christer, et al.
(författare)
-
Contribution of the legs to double-poling performance in elite cross-country skiers.
- 2006
-
Ingår i: Medicine and science in sports and exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 38:10, s. 1853-60
-
Tidskriftsartikel (refereegranskat)abstract
- In the classical style of cross-country skiing, the double-poling (DP) technique, which is regarded as an upper-body exercise, is used on the flatter parts of a course. Limited biomechanical and physiological data are available about DP compared with other cross-country skiing techniques. The purpose of the present study was to evaluate the possible role of the lower body during DP.Eleven elite cross-country skiers performed two incremental tests using DP roller skiing at 1 degree inclination on a treadmill with or without locking the knee and ankle joints (DPLOCKED and DPFREE). Maximal and peak oxygen uptake (VO2max and VO2peak) during classic diagonal skiing and DP, respectively, were measured. In addition, heart rate, blood lactate concentration, and maximal DP velocity (Vmax) were determined. Pole-ground reaction forces and joint angles (elbow, hip, knee, and ankle) were analyzed.The skiers obtained 7.7% higher VO2peak, 9.4% higher Vmax, and 11.7% longer time to exhaustion during DPFREE compared with DPLOCKED (all P < 0.05). There was a higher heart rate and blood lactate concentration in DPLOCKED at submaximal stages (all P < 0.05), with no difference in oxygen consumption. At 85% Vmax, corresponding to approximately 81% VO2peak FREE, the differences in physiological variables were accompanied by a 13.6% higher poling frequency, a 4.9% shorter poling phase, 13.3% shorter recovery phase, and 10.9% lower relative pole force in DPLOCKED (all P < 0.05).Movements of the knee and ankle joints are an integrative part in the skillful use of the DP technique, and restriction of the motion in these joints markedly affects both biomechanical and physiological variables, impairing DP performance.
|
|
| 8. |
- Berglund, Tomas, et al.
(författare)
-
Epi-convergence of minimum curvature variation B-splines
- 2003
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We study the curvature variation functional, i.e., the integral over the square of arc-length derivative of curvature, along a planar curve. With no other constraints than prescribed position, slope angle, and curvature at the endpoints of the curve, the minimizer of this functional is known as a cubic spiral. It remains a challenge to effectively compute minimizers or approximations to minimizers of this functional subject to additional constraints such as, for example, for the curve to avoid obstacles such as other curves. In this paper, we consider the set of smooth curves that can be written as graphs of three times continuously differentiable functions on an interval, and, in particular, we consider approximations using quartic uniform B- spline functions. We show that if quartic uniform B-spline minimizers of the curvature variation functional converge to a curve, as the number of B-spline basis functions tends to infinity, then this curve is in fact a minimizer of the curvature variation functional. In order to illustrate this result, we present an example of sequences of B-spline minimizers that converge to a cubic spiral.
|
|
| 9. |
|
|
| 10. |
- Gustafsson, Magnus, 1969, et al.
(författare)
-
Roto-translational Raman spectra of pairs of hydrogen molecules from first principles
- 2009
-
Ingår i: J. Chem. Phys.. - : AIP Publishing. ; 130
-
Tidskriftsartikel (refereegranskat)abstract
- We calculate the collision-induced, roto-translational, polarized, and depolarized Raman spectra of pairs of H2 molecules. The Schrödinger equation of H2–H2 scattering in the presence of a weak radiation field is integrated in the close-coupled scheme. This permits the accounting for the anisotropy of the intermolecular potential energy surface and thereby it includes mixing of polarizability components. The static polarizability invariants, trace and anisotropy, of two interacting H2 molecules were obtained elsewhere [Li et al., J. Chem. Phys. 126, 214302 (2007)] from first principles. Here we report the associated spherical tensor components which, along with the potential surface, are input in the calculation of the supramolecular Raman spectra. Special attention is paid to the interferences in the wings of the rotational S0(0) and S0(1) lines of the H2 molecule. The calculated Raman pair spectra show reasonable consistency with existing measurements of the polarized and depolarized Raman spectra of pairs of H2 molecules.
|
|
