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| 2. |
- Danielsson, Åke, et al.
(författare)
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A controlled randomized trial of budesonide versus prednisolone retention enemas in active distal ulcerative colitis
- 1987
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 22:8, s. 987-992
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Tidskriftsartikel (refereegranskat)abstract
- Sixty-four patients with active distal ulcerative colitis participated in a multicentre, randomized, investigator-blind trial to compare the effect of budesonide enema, 2 mg/100 ml, with prednisolone disodium phosphate enema, 31.25 mg/100 ml. Budesonide is a new potent corticosteroid with a rapid first-pass elimination. The patients were treated for 4 weeks, and the efficacy of the drugs were evaluated by sigmoidoscopy, histology, and subjective symptoms after 2 and 4 weeks. After 4 weeks of treatment 16 of 31 patients (52%) receiving budesonide enema had healed endoscopically, compared with 8 of 33 (24%) (p = 0.045) receiving prednisolone enema. Budesonide was superior to prednisolone in terms of both significantly improved sigmoidoscopic and histologic scores and subjective symptoms evaluated by visual analogue scales. The patients receiving prednisolone had a significant depression of endogenous cortisol levels during the treatment period, but not the patients receiving budesonide. Budesonide enema seems to be a promising therapy for active distal ulcerative colitis and causes no adverse reactions
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| 4. |
- Forsgren, Katarina, et al.
(författare)
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Deposition of HfO2 thin films in HfI4-based processes
- 2002
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 149:10, s. F139-F144
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Tidskriftsartikel (refereegranskat)abstract
- This study describes deposition of HfO2 thin films by chemical vapor deposition (CVD) and atomic layer deposition (ALD) using HfI4 as the metal precursor. The layer-by-layer growth was also studied in real time with a quartz crystal microbalance. In ALD, the deposition rate was independent of the growth temperature, whereas in CVD, an exponential rate increase was observed. Monoclinic HfO2 was deposited on MgO and poly-Si substrates in a wide temperature range, and the choice of substrate had a strong influence on the orientation of the films. Epitaxial growth of HfO2 was observed on MgO(001) substrates at 400-500°C in the ALD process and at 500-600°C in the CVD process. The electrical characterization showed that the crystallinity of the films had a stronger influence on the dielectric constant than did the film thickness.
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| 5. |
- Forsgren, Katarina, et al.
(författare)
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Iodide-Based Atomic Layer Deposition of ZrO2 : Aspects of Phase Stability and Dielectric Properties
- 2002
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Ingår i: Chemical Vapor Deposition. - 0948-1907 .- 1521-3862. ; 8:3, s. 105-109
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Tidskriftsartikel (refereegranskat)abstract
- This study is an investigation into the influence of temperature, substrate, and thickness on the properties of ZrO2 thin films grown by atomic layer deposition (ALD). ZrI4 and H2O2 were used as source materials, and films deposited at temperatures between 250 °C and 500 °C consisted of mixed tetragonal and monoclinic ZrO2. The phase content and electrical properties of films of 3–30 nm thickness were studied for different temperatures and substrates. The films crystallized at smaller thicknesses on the Pt/Ti/SiO2/Si (denoted Pt in the following text) substrate than on polycrystalline Si (poly-Si) and MgO(001). It was also found that the film thickness had a stronger effect on the dielectric constant than either the growth temperature or the substrate.
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| 6. |
- Gidhagen, Lars, et al.
(författare)
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Towards climate services for European cities : Lessons learnt from the Copernicus project Urban SIS
- 2020
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Ingår i: Urban Climate. - Amsterdam, Netherlands : Elsevier. - 2212-0955. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- The growing share of Europe's population living in cities makes urban climate change impact assessment and adaptation a critical issue. The urban environment is characterized by its sensitivity to small-scale meteorological, hydrological and environmental processes. These are generally not fully described in climate models, largely because of the models' insufficient spatial resolution. The Urban SIS climate service offers historical and future simulated data downscaled to 1 km × 1 km resolution over selected European metropolitan areas. The downscaled data are subsequently used as input to air quality and hydrological impact models, all made available to users as Essential Climate Variables and Sectoral Impact Indicators through a web portal. This paper presents the Urban SIS climate service and demonstrates its functionality in a case study in Stockholm city, Sweden. Good model performance was attained for intra-city temperature gradients and small-scale precipitation extremes. Less positive results were obtained for large-scale precipitation and hydrology, mainly due to an insufficient domain size in the meteorological and climate modelling, in turn related to the substantial computational requirements. An uncertainty classification approach was developed to aid the interpretation and user application of the data. We hope our lessons learnt will support future efforts in this direction.
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| 7. |
- Gjirja, Savo, 1945, et al.
(författare)
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Fischer- Tropsch-Synthesis Fuels as Diesel Engine Fuel-Fuel of the Future
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Fischer-Tropsch (F-T) catalytic conversion process can be used to synthesize diesel fuels from a variety of feed-stocks, including coal, natural gas and biomass. Synthetic diesel fuels can have very low sulfur and aromatic content, and excellent autoignition characteristics. Moreover, Fischer-Tropsch diesel fuels may also be economically competitive with regular diesel fuel if produced in large volumes.The aim of this investigation is to reveal and analyze the effects of F- T fuels on a research diesel engine performance. Previous engine laboratory tests indicate that F-T fuels are promising alternative fuels because they can be used in unmodified diesel engines, and substantial quantitative exhaust emission reductions can be reached. Also substantial qualitative reductions, e.g. reduction of the number of hazardous chemicals and reduction of the concentration of hazardous chemicals in the exhausts may be realized. Since the engine performance is close1y related to in-cylinder processes, a detailed thermodynamic analysis has been performed revealing the real thermo-chemistry history. The experimental results have shown that F-T fuels have a beneficial effect not only on the emissions levels, but also on other energetic parameters of the engine. Heat release analysis has shown that ignition delay, cylinder peak pressure, heat release gradient and indicated efficiency are affected as well.Two different mixtures of FT-fuels with variation in carbon chain branching and, to a certain extent variation in chain 1ength were tested and their results were compared with those obtained from conventional fuel (MK 1). The selected optimized F-T fuels mixture were further tested according to the 13 mode ECE R49 test cycle and were found as good competitive alternative diesel fuels.
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| 9. |
- Olsson, Bengt, et al.
(författare)
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A decision support model for individual tree stump harvesting options based on criteria for economic return and environmental protection
- 2017
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Ingår i: Scandinavian Journal of Forest Research. - : Taylor & Francis Group. - 0282-7581 .- 1651-1891. ; 32, s. 246-259
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Tidskriftsartikel (refereegranskat)abstract
- Based on principles of multi-criteria analysis techniques, a model (MAPStump-E) for decision support on stump harvesting at stand level was developed. The model applies the concept that each stump can be attributed production values (economic) and environmental values (here soil protection and water quality). Individual tree stump information was incorporated directly from the production reports of harvesters and combined with high-resolution Geographical Information System data on topography and soil type to create a production submodel and a soil and water vulnerability submodel (SWM). To test the model, it was applied to a 45-ha study forest in south-central Sweden and the outcome of nine scenarios with varying bioenergy prices and environmental protection levels was examined. Combined analysis of the effects of production and environmental criteria on total dry mass of harvestable stumps at the study site showed that biomass prices had a stronger influence than environmental criteria. Conflict stumps were defined as stumps suitable for harvest based on production criteria, but unsuitable based on soil and water protection criteria. In a ?medium? price scenario, the proportion of conflict stumps at the study site ranged from 6% to 18%, depending on protection level set.
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| 10. |
- Ranius, Thomas, et al.
(författare)
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The effects of logging residue extraction for energy on ecosystem services and biodiversity : a synthesis
- 2018
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Ingår i: Journal of Environmental Management. - : Elsevier. - 0301-4797 .- 1095-8630. ; 209, s. 409-425
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Forskningsöversikt (refereegranskat)abstract
- We review the consequences for biodiversity and ecosystem services from the industrial-scale extraction of logging residues (tops, branches and stumps from harvested trees and small-diameter trees from thinnings) in managed forests. Logging residue extraction can replace fossil fuels, and thus contribute to climate change mitigation. The additional biomass and nutrients removed, and soils and other structures disturbed, have several potential environmental impacts. To evaluate potential impacts on ecosystem services and biodiversity we reviewed 279 scientific papers that compared logging residue extraction with non-extraction, the majority of which were conducted in Northern Europe and North America. The weight of available evidence indicates that logging residue extraction can have significant negative effects on biodiversity, especially for species naturally adapted to sun-exposed conditions and the large amounts of dead wood that are created by large-scaled forest disturbances. Slash extraction may also pose risks for future biomass production itself, due to the associated loss of nutrients. For water quality, reindeer herding, mammalian game species, berries, and natural heritage the results were complicated by primarily negative but some positive effects, while for recreation and pest control positive effects were more consistent. Further, there are initial negative effects on carbon storage, but these effects are transient and carbon stocks are mostly restored over decadal time perspectives. We summarize ways of decreasing some of the negative effects of logging residue extraction on specific ecosystem services, by changing the categories of residue extracted, and site or forest type targeted for extraction. However, we found that suggested pathways for minimizing adverse outcomes were often in conflict among the ecosystem services assessed. Compensatory measures for logging residue extraction may also be used (e.g. ash recycling, liming, fertilization), though these may also be associated with adverse environmental impacts.
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