| 21. |
- Froitzheim, Jan, 1981, et al.
(författare)
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Cr evaporation of metallic interconnects: A novel method for quantification
- 2009
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Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781566777391 ; 25:2 PART 2, s. 1423-1428
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Konferensbidrag (refereegranskat)abstract
- Chromium evaporation from metallic interconnects in SOFCs is commonly poisoning the cathode of SOFCs. To reduce chromium evaporation, rather thick coatings have been deposited using various coating techniques. In this study, a 22% Cr ferritic steel has been coated with thin films (
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| 22. |
- Froitzheim, Jan, 1981, et al.
(författare)
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Investigation of Chromium Volatilization from FeCr Interconnects by a Denuder Technique
- 2010
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 157:9, s. B1295-B1300
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Tidskriftsartikel (refereegranskat)abstract
- A technique is presented for accurate and time-resolved quantification of chromium volatilization from alloys at high temperature. A denuder tube which is coated with Na2CO3 is placed downstream of the samples. CrO2(OH)(2) that evaporated from the samples is collected on the denuder and converted to the thermally stable Na2CrO4. The chromate is then dissolved in water and determined quantitatively. Three commercially available ferritic 22% Cr steels intended for use as solid oxide fuel cell interconnect materials (Sanergy HT, Crofer 22 APU, and ZMG 232) have been investigated with respect to chromium volatilization and oxidation rate. The effect on chromium volatilization of a submicrometer cobalt coating on the steel surface is reported. Comparisons are made with a conventional thick ceramic coating. The experiments are carried out at 850 degrees C in N-2 - 20% O-2 - 3% H2O atmosphere. The submicrometer Co coatings proved to be very efficient, reducing Cr volatilization by 1 order of magnitude. Microscopic studies show that both uncoated steel and steel coated with a submicrometer cobalt film develop two-layered oxide scales with the bottom part consisting of a Cr-rich corundum-type oxide. The uncoated samples develop a top layer consisting of (Cr, Mn)(3)O-4 oxide, whereas the Co-coated samples exhibit a top layer consisting of Co-rich spinel oxide. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3462987] All rights reserved.
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| 23. |
- Fröberg, Linus, et al.
(författare)
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Vertical InAs nanowire wrap-gate FETs
- 2006
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Ingår i: Book of abstracts: Semicond Nanowires Symp, Eindhoven, The Netherlands (2006).
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Konferensbidrag (refereegranskat)
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| 24. |
- Gallo, Yann, et al.
(författare)
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Investigation of Late-Cycle Soot Oxidation Using Laser Extinction and In-Cylinder Gas Sampling at Varying Inlet Oxygen Concentrations in Diesel Engines
- 2017
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Ingår i: Fuel. - : Elsevier BV. - 1873-7153 .- 0016-2361. ; 193, s. 308-314
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on the relative importance of O2 and OH as oxidizers of soot during the late cycle in diesel engines, where the soot oxidation is characterized in an optically accessible engine using laser extinction measurements. These are combined with in cylinder gas sampling data from a single cylinder engine fitted with a fast gas sampling valve. Both measurements confirm that the in-cylinder soot oxidation slows down when the inlet concentration of O2 is reduced. A 38% decrease in intake O2 concentration reduces the soot oxidation rate by 83%, a non-linearity suggesting that O2 in itself is not the main soot oxidizing species. Chemical kinetics simulations of OH concentrations in the oxidation zone and estimates of the OH soot oxidation rates point towards OH being the dominant oxidizer.
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| 25. |
- Gissén, Charlott, et al.
(författare)
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Comparing energy crops for biogas production Yields, energy input and costs in cultivation using digestate and mineral fertilisation
- 2014
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 64, s. 199-210
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of six crops grown in southern Sweden for biogas production (hemp, sugar beet, maize, triticale, grass/clover ley, winter wheat) showed varying performance regarding methane yield per hectare and energy input and costs in the production and supply of crops as biogas feedstock. The highest biomass and biogas yield was observed for sugar beet. Crops with lower risk of negative environmental impact in cultivation, such as ley and hemp, produced less than half the methane energy yield per hectare. Triticale, also having less risk of negative environmental impact, gave an energy yield similar to that of winter wheat grain and maize. Replacing most of the mineral fertiliser with biogas digestate did not, with the exception for hemp, influence crop yields per hectare, but energy input in cultivation decreased by on average 34% for the six crops tested. For hemp and sugar beet the biogas feedstock costs for the freshly harvested crop per GJ methane were close to that of the economic reference crop, winter wheat grain. For maize, beet tops and first and second year ley, the feedstock costs were lower, and for triticale much lower. When ensiled crops were used for biogas the feedstock costs increased and only those of triticale silage remained slightly lower than the cost of dried wheat grain. However, all feedstock costs were so high that profitable biogas production based solely on ensiled crops would be difficult to achieve at present Swedish biogas sales prices. (c) 2014 Elsevier Ltd. All rights reserved.
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| 26. |
- Gustavsson, Carl Gunnar, et al.
(författare)
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Thrombotic occlusion of all left coronary branches in a young woman with severe ulcerative colitis
- 2011
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Ingår i: ISRN Cardiology. - : Hindawi Limited. - 2090-5580 .- 2090-5599.
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Tidskriftsartikel (refereegranskat)abstract
- Background. The thrombosis risk is increased in active ulcerative colitis. The limited number of reported complications have predominantly been cerebrovascular but other vessel territories may also be affected. Patient. During a severe attack of ulcerative colitis a 37-year-old woman suffered occlusion of all left coronary artery branches. Serial angiographies showed progressive recanalisation of the coronary arteries during anticoagulation, but no atherosclerotic stenosis. The cause of infarction was thus considered to be an extensive coronary thrombosis. However, a large battery of blood tests failed to identify any procoagulant abnormality. Conclusion. Evidence is now accumulating that the increased thrombosis risk also may involve the coronary arteries, even in young patients. To the best of our knowledge this is the third reported case ofmyocardial infarction despite angiographically normal coronary arteries in a patient with active ulcerative colitis. The extent of affected myocardiumwas in this case exceptionally large.
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| 27. |
- Gustavsson, Karl-Erik, et al.
(författare)
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Different types of organic pop-up fertilizers in carrot cultivation: Effects on the concentrations of polyacetylenes and sugars
- 2018
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Ingår i: Scientia Horticulturae. - : Elsevier BV. - 0304-4238 .- 1879-1018. ; 230, s. 126-133
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Tidskriftsartikel (refereegranskat)abstract
- The effects on the concentration of falcarinol-type of polyacetylenes and sugars at harvest and after storage of carrots after application of different types (powder, digestate, two micro-granular) of organic pop-up fertilizer, where the fertilizer was placed in small amounts together with the seeds, were studied. Both groups of investigated compounds reflect important sensory attributes of the carrots, while polyacetylenes are considered as potentially health-promoting compounds. Results showed that the type of pop-up organic fertilizer as well as the dose can affect the concentrations of polyacetylenes and sugars. The dose of nitrogen applied did not seem to alone affect the concentration of polyacetylenes in carrots, while low amounts of applied phosphorus could be related to higher amounts of falcarindiol. The liquid digestate resulted in the highest concentrations of poly acetylenes in two of the treatments, even though the applied doses of digestate contained among the lowest amounts of nutrients. Storage resulted in both increases and decreases of total polyacetylenes, falcarindiol and falcarinol, while falcarindiol-3-acetate generally increased during storage. The sugars showed less variation due to the type or dose of fertilizer applied, as compared with the polyacetylenes.
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| 28. |
- Gärdenäs, Annemieki, et al.
(författare)
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Estimating soil carbon stock changes by process-based models and soil inventories : uncertainties and complementarities
- 2011
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Ingår i: Soil Carbon in Sensitive European Ecosystems. - Oxford : Wiley-Blackwell. - 9781119970019
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Bokkapitel (refereegranskat)abstract
- In this chapter, four examples of scientific questions and challenges in which process-oriented modelling could provide a useful contribution for accounting soil organic carbon (SOC) stocks and changes are presented. These challenges include cases i) when measurements are either time-consuming and/or expensive or there are methodological limitations; ii) an attempt to verify the national soil inventory estimates through comparison with process-based model estimates; iii) prediction of the potential impact on SOC changes due to land-use change; and iv) a comparison of different scenarios for mitigating GHG-emissions. We found that the use of process-based models offers a complementary way to account SOC change and provides an option for assessing the potential impact of climate and land-use change on SOC stocks. However, uncertainty in model estimates is inherent and needs to be communicated. Progress has been made in the assessment of uncertainty and there is growing awareness of how this uncertainty can be communicated. Suggestions for collaborative approaches are presented in order to reduce the uncertainties.
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| 29. |
- Hansson, Malin, 1967, et al.
(författare)
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CCL28 is increased in human Helicobacter pylori induced gastritis and mediates recruitment of gastric IgA-secreting cells.
- 2008
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Ingår i: Infection and Immunity. - 0019-9567. ; 76:7, s. 3304-11
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Tidskriftsartikel (refereegranskat)abstract
- Human Helicobacter pylori infection gives rise to an active chronic gastritis and is a major risk factor for the development of duodenal ulcer disease and gastric adenocarcinoma. The infection is accompanied by a large accumulation of immunoglobulin A (IgA)-secreting cells in the gastric mucosa, and following mucosal immunization only H. pylori-infected volunteers mounted a B-cell response in the gastric mucosa. To identify the signals for recruitment of gastric IgA-secreting cells, we investigated the gastric production of CCL28 (mucosa-associated epithelial chemokine) and CCL25 (thymus-expressed chemokine) in H. pylori-infected and uninfected individuals and the potential of gastric B-cell populations to migrate toward these chemokines. Gastric tissue from H. pylori-infected individuals contained significantly more CCL28 protein and mRNA than that from uninfected individuals, while CCL25 levels remained unchanged. Chemokine-induced migration of gastric lamina propria lymphocytes isolated from patients undergoing gastric resection was then assessed using the Transwell system. IgA-secreting cells and IgA+ memory B cells from H. pylori-infected tissues migrated toward CCL28 but not CCL25, while the corresponding cells from uninfected patients did not. Furthermore, IgG-secreting cells from H. pylori-infected patients did not migrate to CCL28 but instead to CXCL12 (SDF-1). However, chemokine receptor expression did not correlate to the migratory pattern of the different B-cell populations. These studies are the first to show increased CCL28 production during gastrointestinal infection in humans and provide an explanation for the large influx of IgA-secreting cells to the gastric mucosa in H. pylori-infected individuals.
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| 30. |
- Hellenbrand, Markus, et al.
(författare)
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Capacitance Measurements in Vertical III-V Nanowire TFETs
- 2018
-
Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 39:7, s. 943-946
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Tidskriftsartikel (refereegranskat)abstract
- By measuring scattering parameters over a wide range of bias points, we study the intrinsic gate capacitance as well as the charge partitioning of vertical nanowire tunnel field-effect transistors (TFETs). The gate-to-drain capacitance Cgd is found to largely dominate the on-state of TFETs, whereas the gate-to-source capacitance Cgs is sufficiently small to be completely dominated by parasitic components. This indicates that the tunnel junction on the source side almost completely decouples the channel charge from the small-signal variation in the source, while the absence of a tunnel junction on the drain side allows the channel charge to follow the drain small-signal variation much more directly.
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