| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Lundström, Ulla, et al.
(författare)
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Advances in understanding the podzolization process resulting from a multidisciplinary study of three coniferous forest soils in the Nordic Countries
- 2000
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Ingår i: Geoderma. - 0016-7061 .- 1872-6259. ; 94:04-feb, s. 335-353
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Tidskriftsartikel (refereegranskat)abstract
- Geochemical, mineralogical, micromorphological, microbiological, hydrochemical and hpdrological joint investigations were performed at two coniferous podzolic sites in the north of Sweden and at one in the south of Finland. Mycorrhizal fungi were found to create numerous pens (3-10-mu m diameter) in many weatherable mineral grains in the eluvial (E) horizon. During the growing season, identified low molecular weight (LMW) organic acids such as citric, shikimic, oxalic and fumaric acids comprised 0.5-5% of the DOC and 0.5-15% of the total acidity in soil solutions. Between 20% and 40% of the dissolved Al was bound to the identified LMW organic acids. Mineral dissolution via complexing LMW acids, probably exuded in part by the mycorrhiza hyphae, is likely to be a major weathering process in podzols. We found no evidence for a decreasing C/metal ratio of the migrating organo-metal complexes that could explain the precipitation of secondary Fe and AL in the illuvial (B) horizon. Instead, microbial degradation of organic ligands resulting in the release of ionic,Al and Fe to the soil solution may he an important process facilitating the formation of solid Al-SI-OH and Fe-OH phases in the podzol B horizon. However, within the B horizon transport as proto-imogilite (PI) sols might be possible. In the B horizon, the extractable,Al and Fe was predominantly inorganic. The large specific surface area (SSA) removable by oxalate extraction, the high point of zero charge salt effect (PZSE), the low cation exchange capacity (CEC) and the high sulphate exchange capacity (SEC), painted to the presence of short-range ordered variable charge phases. Imogolite type material (ITM) was indeed identified in all B horizons by IR spectroscopy and crystalline imogolite was found in the deep B horizon of one profile. Mossbauer spectroscopy indicated that Fe in the form of ferrihydrite was formed by intergrowth with an Al-Si-OH phase. The high amounts of Fe and Al transported from the O to the E horizon indicate that there could be an upward transport of these elements before they are leached to the B horizon. We hypothesize that the LMW Al complexes an transported by hyphae to the mor (O) layer, partly released and subsequently complexed by high molecular weight (HMW) acids.
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| 3. |
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| 4. |
- Wagner, W, et al.
(författare)
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Europe ambivalent on biotechnology
- 1997
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Ingår i: Nature. - London : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 387, s. 845-847
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Tidskriftsartikel (refereegranskat)abstract
- The Eurobarometer on Biotechnology (46.1) was conducted during October and November 1996. The survey conducted in each EU (European Union) country used a multi-stage random sampling procedure and provided a statistically representative sample of national residents aged 15 and over. The total sample within the EU was 16,246 respondents (about 1,000 per EU country). The survey questionnaire was designed by the authors as part of a larger study involving the comparative analysis of public perceptions, media coverage and public policy in relation to biotechnology from 1973 to the present.
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| 5. |
- Dahlén, Leon, et al.
(författare)
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Analysis of Two Sliding Contacts Inside a Radial Piston Hydraulic Motor
- 2002
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Ingår i: Proceedings at 5th JFPS International Symposium on Fluid Power, Nov. 12-15, 2002, Nara, Japan.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents an investigation of the torque losses in a hydraulic motor of radial piston type commonly used in industrial hydrostatic transmissions. When the speed of the hydraulic motor is decreased an increase of the torque loss can be measured. In order to investigate the reason for this increase a combination of experimental and theoretical studies is performed with special focus on two sliding contacts-the distributor valve and the piston-cam roller contact. The theoretical analysis of the contacts reveals that the distributor valve contribute more to torque and power losses compared to the piston-cam roller contacts and largely to the external leakage of the motor. At low speeds the piston-cam roller contact will enter the mixed lubrication regime.
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| 6. |
- Eilertsen, G., et al.
(författare)
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Similarities and differences in the experience of fatigue among people living with fibromyalgia, multiple sclerosis, ankylosing spondylitis and stroke
- 2015
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Ingår i: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 24:13-14, s. 2023-2034
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Tidskriftsartikel (refereegranskat)abstract
- Aims and objectives: To elucidate the experience of fatigue across several long-term illnesses, focusing on the similarities and differences. Background: Fatigue is common to many long-term illnesses, but it has been studied mainly within the context of a single illness; qualitative studies comparing the experience and its impact on daily life across different long-term illnesses are lacking. Design: Qualitative design. Methods: A secondary analysis was conducted of five original interview studies involving 95 persons with ankylosing spondylitis, fibromyalgia, multiple sclerosis or stroke. Results: Similarities and differences concerning experiences of fatigue were found across the studied long-term illnesses. All patients expressed the perception of having an unfamiliar body. Fatigue was also commonly expressed as unpredictable, uncontrollable and invisible to others. Differences were related to a constant versus a varying condition, a sudden and an uncontrollable sleepiness, a mutual reinforcement with pain and increased stress sensitivity. A lack of energy and a need for sleep and rest were common experiences, as was the impact on social relationships. There were also similarities regarding how the patients managed their daily life. The search for practical solutions and attitude adjustment differed with the fatigue characteristics. All patients felt a lack of understanding and disbelief from others. Conclusion and relevance to clinical practice: Fatigue is commonly expressed by patients with long-term illnesses. Variations in experience are related to the type of diagnosis. The disparity between experiences influences how patients managed and adjusted to the conditions of everyday life. The illness-specific characteristics of fatigue warrant increased clinical awareness and may allow professionals to offer adequate information and establish effective methods of managing the condition. The feeling of invisibility and difficulty describing the experience of fatigue in particular highlights this need. © 2015 John Wiley & Sons Ltd.
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| 7. |
- Liu, Dongming, 1987-, et al.
(författare)
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Influence of Nanoparticle Surface Coating on Electrical Conductivity of LDPE/Al2O3 Nanocomposites for HVDC Cable Insulations
- 2017
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Ingår i: IEEE transactions on dielectrics and electrical insulation. - : IEEE. - 1070-9878 .- 1558-4135. ; 24:3, s. 1396-1404
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Tidskriftsartikel (refereegranskat)abstract
- LDPE/metal oxide nanocomposites are promising materials for future high-voltage DC cable insulation. This paper presents data on the influence of the structure of the nanoparticle coating on the electrical conductivity of LDPE/Al2O3 nanocomposites. Al2O3 nanoparticles, 50 nm in size, were coated with a series of silanes with terminal alkyl groups of different lengths (methyl, n-octyl and n-octadecyl groups). The density of the coatings in vacuum was between 200 and 515 kg m(-3,) indicating substantial porosity in the coating. The dispersion of the nanoparticles in the LDPE matrix was assessed based on statistics for the nearest-neighbor particle distance. The electrical conductivity of the nanocomposites was determined at both 40 and 60 degrees C. The results show that an appropriate surface coating on the nanoparticles allowed uniform particle dispersion up to a filler loading of 10 wt.%, with a maximum reduction in the electrical conductivity by a factor of 35. The composites based on the most porous octyl-coated nanoparticles showed the greatest reduction in electrical conductivity and the lowest temperature coefficient of electrical conductivity of the composites studied.
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| 8. |
- Medronho, Bruno, et al.
(författare)
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Probing cellulose–solvent interactions with self-diffusion NMR : Onium hydroxide concentration and co-solvent effects
- 2023
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 303
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Tidskriftsartikel (refereegranskat)abstract
- The molecular self-diffusion coefficients were accessed, for the first time, in solutions of microcrystalline cellulose, dissolved in 30 wt% and 55 wt% aqueous tetrabutylammonium hydroxide, TBAH (aq), and in mixtures of 40 wt% TBAH (aq) with an organic co-solvent, dimethylsulfoxide (DMSO), through pulsed field gradient stimulated echo NMR measurements. A two-state model was applied to estimate α (i.e., average number of ions that “bind” to each anhydroglucose unit) and Pb (i.e., fraction of “bound” molecules of DMSO, TBAH or H2O to cellulose) parameters. The α values suggest that TBA+ ions can bind to cellulose within 0.5 TBA+ to 2.3 TBA+/AGU. On the other hand, the Pb parameter increases when raising cellulose concentration for TBA+, DMSO and water in all solvent systems. Data suggests that TBAH interacts with the ionized OH groups from cellulose forming a sheath of bulky TBA+ counterions which consequently leads to steric hindrance between cellulose chains.
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| 9. |
- Nilsson, Fritjof, et al.
(författare)
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Influence of water uptake on the electrical DC-conductivity of insulating LDPE/MgO nanocomposites
- 2017
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Ingår i: Composites Science And Technology. - : Elsevier BV. - 0266-3538 .- 1879-1050. ; 152, s. 11-19
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Tidskriftsartikel (refereegranskat)abstract
- Low-density polyethylene (LDPE), typically in cross-linked form, is currently the main insulation material for extruded high voltage cables. The DC-conductivity of LDPE can be reduced 100 times by adding 1-3 wt% well-dispersed metal-oxide nanoparticles (MgO, ZnO, Al2O3), but the underlying physics remain unclear. One of several feasible explanations is that the nanoparticles attract electrical charges, polar molecules (H2O and crosslinking by-products) and ions (H+, OH-, salts and ionic species originating from the crosslinking by-products), and thus clean the polymer. Effective media FEM simulations, assuming that the polymer conductivity is proportional to the moisture content, were used in order to examine this hypothesis. Water sorption measurements for LDPE and MgO/LDPE nanocomposites were conducted as experimental input. The simulations could conceptually predict the experimentally measured composite conductivities. The hypothesis was further strengthened by DC-conductivity measurements on LDPE and MgO/LDPE nanocomposites at 0 and 50% relative humidity (RH), showing a 100-fold conductivity increase for the nanocomposite at the elevated humidity. The DC-conductivity of the most insulating composite (3 wt% MgO) was below 10(-16) S/m after 64 h at 60 degrees C and 0% RH, using an electric field of ca 30 kV/mm. The long-term insulation efficiency of an insulating polymer nanocomposite is thus optimal if the material is carefully dried and surrounded by an impenetrable moisture barrier before use.
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| 10. |
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