| 1. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Structural study and proton conductivity in Yb-doped BaZrO3
- 2007
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Ingår i: Solid State Ionics. - 0167-2738. ; 178:(7-10), s. 515-520
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Tidskriftsartikel (refereegranskat)abstract
- Traditional solid state sintering has been used to prepare the perovskite BaZr0.9Yb0.1O3-delta. Analysis of X-ray powder diffraction data shows that an increase of the unit cell parameter, a, was observed compared to undoped BaZrO3. Rietveld analysis of room temperature neutron powder diffraction data confirmed cubic symmetry (space group Pm-3m). Dynamic thermogravimetric analysis (TGA) indicates that the hydration process occurs below 200 degrees C. The strong O-H stretch band, 2500-3500 cm(-1), in the infrared absorbance spectrum clearly manifests the presence of protons in the hydrated material. Proton conductivity was investigated on hydrated and as-prepared samples under dry and wet atmospheres, respectively. Keywords: X-ray diffraction; neutron diffraction; Rietveld refinement; proton conductor; perovskite
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| 2. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Synthesis and structural characterization of perovskite type proton conducting BaZr1-xInxO3-delta (0.0 <= x <= 0.75)
- 2006
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738 .- 1872-7689. ; 177:17-18, s. 1395-1403
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Tidskriftsartikel (refereegranskat)abstract
- Solid state sintering has been used to prepare the cubic perovskite structured compounds BaZr1-xInxO3-delta (0.0 <= x <= 0.75). Analysis of X-ray powder diffraction (XRPD) data reveals that the unit cell parameter, a, increases linearly with an increased Indium concentration. XRPD data was also used to demonstrate the completion of sample hydration, which was reached when the materials showed a set of single-phase Bragg-peaks. Dynamic thermogravimetric analysis (TGA) data showed that approx. 89% of the total number of available oxygen vacancies can be filled in BaZr1-xInxO3-delta for x=0.50, and that the maximum water uptake occurs below 300 degrees C. Rietveld analysis of the room temperature neutron powder diffraction (NPD) data confirmed the average cubic symmetry (space group Pm-3m), and an expansion of the unit cell parameter after the hydration reaction. The strong O-H stretch band, 2500-3500 cm(-1), in the infrared absorbance spectrum clearly manifests the presence of protons in the hydrated material. Proton conductivity of hydrated BaZr1-xInxO3-delta, x=0.75 was investigated during heating and cooling cycles under dry argon atmosphere. The total conductivity during the heating cycle was nearly two orders of magnitude greater than that of cooling cycle at 300 degrees C, whilst these values were similar at higher temperatures i.e. T > 600 degrees C.
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| 3. |
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| 4. |
- Börjesson, Lars, et al.
(författare)
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Residual stresses and microstructure computation for multipass [multirun] welding
- 1997
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Ingår i: The Fifth International Conference on Residual Stresses - ICRS-5. - Linköping : Linköping University Electronic Press. - 9172192100 ; , s. 189-194
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Konferensbidrag (refereegranskat)abstract
- Residual stress studies (by centre-hole drilling and finite element analysis) and microstructural computations (using temperature measurements) were carried out on multirun butt welded steel plates. The plates, 200 mm thickness, were in SIS 2134 material (0.12%C, 1.42%Mn, 0.044%V, 0.014%Ti, 0.038%Al). Welding was by submerged arc welding using ESAB OK AUTROD 12.10 filler material and ESAB OK FLUX 10.80 flux
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| 5. |
- Börjesson, Lars, et al.
(författare)
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Simulation of multipass welding using mixture rules for prediction of material properties
- 1998
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Ingår i: Simulation of materials processing : theory, methods and applications. - Rotterdam : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 905410970X ; , s. 351-357
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Konferensbidrag (refereegranskat)abstract
- Multipass butt welding of two 0.2 m thick steel plates has been investigated. The purpose of the project is to evaluate the residual stresses by experiment and simulations. Temperature dependent material properties were assumed in previous studies. We account for the dependency on temperature history in this work. This has been done by computing the microstructure evolution. This is combined with mixture rules for computing material properties.
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| 6. |
- Börjesson, Lars, et al.
(författare)
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Simulation of multipass welding with simultaneous computation of material properties
- 2001
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Ingår i: Journal of engineering materials and technology. - : ASME International. - 0094-4289 .- 1528-8889. ; 123:1, s. 106-111
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Tidskriftsartikel (refereegranskat)abstract
- Multipass butt welding of two 0.2 m thick steel plates has been investigated. The objective is to calculate residual stresses and compare them with measured residual stresses. The material properties depend on temperature and temperature history. This dependency is accounted for by computing the microstructure evolution and using this information for computing material properties. This is done by assigning temperature dependent material properties to each phase and applying mixture rules to predict macro material properties. Two different materials have been used for the microstructure calculation, one for the base material and one for the filler material
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| 7. |
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| 8. |
- Graf, Wilhelm, et al.
(författare)
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Long-term outcome after surgery for Crohn's anal fistula
- 2016
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Ingår i: Colorectal Disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 18, s. 80-85
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Tidskriftsartikel (refereegranskat)abstract
- AIM: Treatment of Crohn's anal fistula remains challenging and little is known about factors associated with healing. The aim of this study was to assess the rate of healing after surgical treatment and analyse clinical variables related to healing.METHOD: 119 patients (63 female, mean age 36 (±13.7) years with histopathologically verified Crohn's disease underwent a surgical procedure for anal fistula at four main referral centres in Sweden, January 1998 - December 2009. Baseline and treatment-related variables were recorded and analysed for correlation with fistula healing at a final follow-up at a mean 7.2 (median 7.1, 1.0-17.5) years.RESULTS: Of the 119 patients 62 (52%) were healed at final follow-up. Fourteen healed after one procedure and the remaining 48 healed after a further median of 4.0 (2-20) procedures. Ten (8%) patients were subjected to a proctectomy. Final healing was more common in patients operated with a procedure aiming at eradicating the fistula (P=0.0001), without proctitis (P=0.02), and a shorter duration of Crohn' disease (P=.0019).CONCLUSION: Long-term healing of a Crohn's anal fistula can be expected in about half of the patients, usually after repeated surgical treatment. The probability for cure was higher when a curative operation was performed in a patient without proctitis and a shorter duration of Crohn's disease. An attempt to close a Crohn's anal fistula is thus often worthwhile. This article is protected by copyright. All rights reserved.
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| 9. |
- Papadopoulos, Konstantinos, 1989, et al.
(författare)
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Photophysical Ion Dynamics in Hybrid Perovskite MAPbX 3 (X=Br, Cl) Single Crystals
- 2024
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Ingår i: ADVANCED PHYSICS RESEARCH. - 2751-1200. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid organic-inorganic perovskites (HOIPs) are promising candidates for next-generation photovoltaic materials. However, there is a debate regarding the impact of interactions between the organic center and the surrounding inorganic cage on the solar cell's high diffusion lengths. It remains unclear whether the diffusion mechanism is consistent across various halide perovskite families and how light illumination affects carrier lifetimes. The focus is on ion kinetics of (CH3NH3)PbX3 (X = Br, Cl) perovskite halide single crystals. Muon spectroscopy (mu+SR)is employed to investigate the fluctuations and diffusion of ions via the relaxation of muon spins in local nuclear field environments. Within a temperature range of 30-340 K, ion kinetics are studied with and without white-light illumination. The results show a temperature shift of the tetragonal-orthorhombic phase transition on the illuminated samples, as an effect of increased organic molecule fluctuations. This relation is supported by density functional theory (DFT) calculations along the reduction of the nuclear field distribution width between the phase transitions. The analysis shows that, depending on the halide ion, the motional narrowing from H and N nuclear moments represents the molecular fluctuations. The results demonstrate the importance of the halide ion and the effect of illumination on the compound's structural stability and electronic properties.
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| 10. |
- Swanberg, Maria, et al.
(författare)
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MHC2TA is associated with differential MHC molecule expression and susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction
- 2005
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 37:5, s. 486-494
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Tidskriftsartikel (refereegranskat)abstract
- Antigen presentation to T cells by MHC molecules is essential for adaptive immune responses. To determine the exact position of a gene affecting expression of MHC molecules, we finely mapped a previously defined rat quantitative trait locus regulating MHC class II on microglia in an advanced intercross line. We identified a small interval including the gene MHC class II transactivator (Mhc2ta) and, using a map over six inbred strains combined with gene sequencing and expression analysis, two conserved Mhc2ta haplotypes segregating with MHC class II levels. In humans, a -168A --> G polymorphism in the type III promoter of the MHC class II transactivator (MHC2TA) was associated with increased susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction, as well as lower expression of MHC2TA after stimulation of leukocytes with interferon-gamma. We conclude that polymorphisms in Mhc2ta and MHC2TA result in differential MHC molecule expression and are associated with susceptibility to common complex diseases with inflammatory components.
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