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- Davidsson, Kent, 1967, et al.
(författare)
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Potassium, chlorine, and sulfur in ash, particles, deposits, and corrosion during wood combustion in a circulating fluidized-bed boiler
- 2007
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 21:1, s. 71-81
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the addition of chlorine and/or sulfur to the fuel on fly ash composition, deposit formation, and superheater corrosion has been studied during biomass combustion in a circulating fluidized-bed boiler. The chlorine (HCl (aq)) and sulfur (SO2 (g)) were added in proportions of relevance for the potassium chemistry. The composition of the bottom and the fly ashes was analyzed. Gas and particle measurements were performed downstream of the cyclone before the convection pass and the flue gas composition was recorded in the stack with a series of standard instruments and an FTIR analyzer. At the position downstream of the cyclone, a deposit probe was situated, simulating a superheater tube. Deposits on the probe and initial corrosion were examined. It is concluded that addition of sulfur and chlorine increases the formation of submicron particles leading to deposition of potassium sulfate and chloride. The results compare well with earlier work based on laboratory-scale experiments concerning effects of chlorine and sulfur on potassium chemistry.
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| 3. |
- Johansson, Per, 1966, et al.
(författare)
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Mild dementia is associated with increased adrenal secretion of cortisol and precursor sex steroids in women.
- 2011
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Ingår i: Clinical endocrinology. - : Wiley. - 1365-2265 .- 0300-0664. ; 75:3, s. 301-308
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Tidskriftsartikel (refereegranskat)abstract
- Context Sex steroid levels decrease with increasing age, but little is known whether this is of importance for the age-related decline in cognitive function. Design and patients A cross-sectional study of 50 (26 men) consecutive patients under primary evaluation of cognitive impairment (D group) and 18 (9 men) matched healthy controls (C group). Measurements Sex steroid and precursor levels were determined in serum and, when measurable, in cerebrospinal fluid (CSF) using gas chromatography/mass spectroscopy (GC-MS) or liquid chromatography/mass spectroscopy (LC-MS). Sex hormone binding globulin (SHBG) and cortisol concentrations were measured using conventional assays. Results Patients in the D group had higher 24-h urine cortisol levels and increased serum levels of dehydroepiandrosterone (DHEA) and its sulphate ester dihydroepiandrosterone sulphate (DHEAS), androsterone (ADT), and oestrone (E1) and its sulphate ester E1S, compared with the controls. When men and women were analysed separately, increased serum concentrations of E1 and E1S were observed in both D men and D women, whereas increased levels of other sex steroids and cortisol were seen only in D women. Conclusions In both D men and women, serum E1 and E1S levels were increased, whereas other changes were gender specific and only seen in D women. Further studies are needed to determine whether these changes are a cause of, or merely a consequence of, cognitive impairment in elderly subjects.
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| 4. |
- Jonsson, Torbjörn, 1970, et al.
(författare)
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Influence of H2O(g) on the Oxide Microstructure of the Stainless Steel 353MA at 900°C in Oxygen.
- 2007
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 154:11, s. C603-C610
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the impact of water vapor on the corrosion behavior of the austenitic Si-containing FeCrNi steel 353MA at 900°C through a detailed microstructural characterization of the oxide scales formed after 168 h in O2 and in O2 with 40% H2 O. The oxidized samples were investigated by focused ion beam and transmission electron microscopy in combination with energy dispersive X-ray analysis. The microstructural investigation showed that the oxide scales were affected by the presence of water vapor. However, there was no significant difference in scale thickness. In both atmospheres a continuous chromia [Cr-rich (Fe,Cr)2 O3] layer was present beneath the spinel oxides. The influence of water vapor on scale composition is attributed to chromia evaporation by the formation of Cr O2 (OH)2 (g). The ability of the alloy to maintain a continuous chromia layer in spite of chromia evaporation and to avoid breakaway oxidation is attributed to several factors. First, the supply of chromium to the scale by diffusion in the alloy must be rapid. Second, the presence of spinel oxides at the oxide/gas interface may decrease chromia evaporation. Third, the high CrFe ratio in the alloy is suggested to make it difficult to convert the protective chromia to poorly protective hematite. © 2007 The Electrochemical Society.
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| 6. |
- Liu, Fang, 1975, et al.
(författare)
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Investigation of the Evolution of the Oxide Scale Formed on 310 Stainless Steel Oxidized at 600 °C in Oxygen with 40% Water Vapour Using FIB and TEM
- 2009
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Ingår i: Oxidation of Metals. - : Springer Science and Business Media LLC. - 1573-4889 .- 0030-770X. ; 71:1-2, s. 77-105
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Tidskriftsartikel (refereegranskat)abstract
- Detailed microstructure investigations were performed on oxide scales formed on 310 stainless steel exposed isothermally at 600 °C to O2 with 40% watervapour for 1–336 h. FIB microscopy was used to study the evolution of the surface morphology and to prepare cross-section TEM thin foils of the oxide scales. The foils were investigated by analytical transmission electronmicroscopy. The results showed that a thin protective base oxide scale had formed after 1 h. Due to Cr loss from the oxide scale through water vapour induced Cr evaporation, local breakaway oxidation occurs, resulting in the formation of oxide nodules. The development of these nodules depends on whether a new Cr-rich healing layer is formed or not. A model for the evolution of the oxide scale is proposed based on the results regarding the composition and distribution of various phases in the oxide scale and subjacentsteel.
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| 8. |
- Asteman, Henrik, 1973, et al.
(författare)
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Effect of water-vapor-induced Cr vaporization on the oxidation of austenitic stainless steels at 700 and 900 degrees C - Influence of Cr/Fe ratio in alloy and Ce additions
- 2004
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 151:3, s. B141-B150
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Tidskriftsartikel (refereegranskat)abstract
- The oxidation of 153MA, 310 and 353MA austenitic stainless steels was investigated at 700°C and 310 and 353MA at 900°C in O 2 and in O 2 + 40% H 2 O. 153MA was not studied at 900°C because it suffered excessive corrosion. The influence of gas velocity was studied. The oxidized samples were investigated by grazing angle X-ray diffraction, scanning electron microscopy/energy dispersive analysis by X-rays Auger-electron spectroscopy, and glow discharge optical emission spectroscopy. In the presence of water vapor, gas velocity strongly influenced oxidation. This effect is attributed to chromium evaporation in the form of CrO 2 (OH) 2 . Exposure in O 2 + 40% H 2 O at 700°C using high flow rates caused breakaway corrosion on all alloys. At 900°C, only the 310 and 353MA alloys were investigated. In O 2 + H 2 O environment, both alloys showed a mass loss at low flow rates due to chromium evaporation. At high flow rates, alloy 310 suffered breakaway corrosion while 353MA did not. The corrosion products consisted of a relatively thin Cr-rich (Cr,Fe) 2 O 3 oxide plus thick, iron-rich oxide islands. The greater corrosion resistance of 310 and 353MA steels in environments where chromium evaporation is a factor is attributed to the high Cr/Fe ratio. In contrast, the presence of Ce and Si in the MA grade steels appears to have little beneficial effect on breakaway corrosion triggered by Cr evaporation. © 2004 The Electrochemical Society. All rights reserved.
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| 9. |
- Berndt, Sonja I., et al.
(författare)
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Genome-wide meta-analysis identifies 11 new loci for anthropometric traits and provides insights into genetic architecture
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:5, s. 501-U69
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Tidskriftsartikel (refereegranskat)abstract
- Approaches exploiting trait distribution extremes may be used to identify loci associated with common traits, but it is unknown whether these loci are generalizable to the broader population. In a genome-wide search for loci associated with the upper versus the lower 5th percentiles of body mass index, height and waist-to-hip ratio, as well as clinical classes of obesity, including up to 263,407 individuals of European ancestry, we identified 4 new loci (IGFBP4, H6PD, RSRC1 and PPP2R2A) influencing height detected in the distribution tails and 7 new loci (HNF4G, RPTOR, GNAT2, MRPS33P4, ADCY9, HS6ST3 and ZZZ3) for clinical classes of obesity. Further, we find a large overlap in genetic structure and the distribution of variants between traits based on extremes and the general population and little etiological heterogeneity between obesity subgroups.
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| 10. |
- Dennersten, Ulrika, et al.
(författare)
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Lung function in the aging Swedish cystic fibrosis population.
- 2009
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Ingår i: Respiratory medicine. - : Elsevier BV. - 1532-3064 .- 0954-6111. ; 103:7, s. 1076-82
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Tidskriftsartikel (refereegranskat)abstract
- Swedish Cystic Fibrosis (CF) care follows international guidelines in general. The only difference in our CF care package since 25 years is the physiotherapy regimen. Airway clearance therapy has since the early 1980s, from the day of diagnosis, been based upon daily physical exercise in conjunction with techniques for transporting and evacuating mucus. Postural Drainage+/-percussion and vibration has not been used in any age. The aim of this study was to evaluate our CF care package. Lung function data from the start of the study and with a 3-year interval were collected in the entire Swedish CF population > or =7 years old. Data were analysed for the age groups 7-17 and > or =18 years of age. Change of lung function over the study period was calculated. The impact of chronic Pseudomonas aeruginosa (Pa) colonisation and basal FEV(1)%p was also evaluated in a linear mixed model. Data from 99% of the country-wide CF population were available at inclusion. Mean FEV(1)%p was 90+/-21 vs 73+/-26 in the different age groups and mean VC%p was 94+/-18 vs 91+/-20. Forty percent of the adult group was > or =30 years old. Overall, 41% were chronically Pa colonised. Mean annual FEV(1)%p rate of decline was 0.77 and 0.64 in the different age groups. Lung function among Swedish CF patients is good and annual rate of decline low, even in an old cohort. The large proportion of adult patients emphasises future demands on CF care.
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