| 1. |
- Öjehagen, A., et al.
(författare)
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A randomized study of long-term out-patient treatment in alcoholics : Psychiatric treatment versus multimodal behavioural therapy, during 1 versus 2 years of treatment
- 1992
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Ingår i: Alcohol and Alcoholism. - : Oxford University Press (OUP). - 0735-0414 .- 1464-3502. ; 27:6, s. 649-658
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Tidskriftsartikel (refereegranskat)abstract
- Seventy-two alcoholic patients (60 men and 12 women) were randomized into four groups who received psychiatric treatment (PT) or multimodal behavioural therapy (MBT), for either 1 or 2 years. PT was based on psychodynamic principles, and MBT is a cognitive-behavioural treatment. The patients accepting treatment had a mean age of 37 ± 9 years, and they were socially stable. There was no difference in attrition rate (35%) in relation to therapy and length of treatment. The rate of favourable drinking outcome during the third year was similar in all four alternatives, at 40-44%. A favourable drinking outcome was predicted by a better initial psychic status and few psychiatric symptoms at intake. In PT patients a favourable outcome was more strongly related to a better psychic status than in MBT patients (P = 0.58). The mean number of sessions, 23, did not differ in relation to outcome. The main conclusion from this study is that there were only small and inconclusive differences between the therapies of different types and different duration.
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| 2. |
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| 3. |
- Stark, A.K., et al.
(författare)
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Effect of atomic oxygen on the mechanical properties of highly graphitized carbon fibers
- 1994
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 32:4, s. 641-644
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Tidskriftsartikel (refereegranskat)abstract
- Material degradation is a serious problem for large structural members that operate in low earth orbit for a long time. In order to study how the mechanical properties of the fibers change in this environment, highly graphitized polyacrylonitrile-based high modulus carbon fibers have been exposed to different fluences of atomic oxygen, the dominant atmospheric element in low earth orbit. Tensile tests were performed on these fibers. Young's modulus and tensile strength decreased with increasing exposure to atomic oxygen. Scanning electron microscopy revealed that the surface of the carbon fiber was severely degraded by the atomic oxygen, and this explains the decreases in Young's modulus and tensile strength
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| 4. |
- Varna, Janis, et al.
(författare)
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A study of the opening displacement of transverse cracks in cross-ply laminates
- 1993
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Ingår i: International journal of damage mechanics. - : SAGE Publications. - 1056-7895 .- 1530-7921. ; 2:3, s. 272-289
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Tidskriftsartikel (refereegranskat)abstract
- Transverse cracks in cross-ply laminates are investigated experimentally to reveal the essential characteristics of their opening displacement under tensile loads. The average crack opening displacement is studied as a function of the longitudinal overall strain and the effects of matrix toughness and transverse ply thickness on this parameter are examined. The interactive effects between closely spaced transverse cracks are also ex amined and found to be significant. Implications of the experimentally observed features on the micromechanics and continuum damage type models are discussed.
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| 5. |
- Öjehagen, A., et al.
(författare)
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Long‐term use of aversive drugs in outpatient alcoholism treatment
- 1991
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Ingår i: Acta Psychiatrica Scandinavica. - : Wiley. - 0001-690X .- 1600-0447. ; 84:2, s. 185-190
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Tidskriftsartikel (refereegranskat)abstract
- In a 2‐year outpatient treatment programme for alcoholics, 90% of the patients used aversive drugs during some part of the treatment period. Long‐term use was significantly related to a favourable drinking outcome during 2 years subsequent to treatment compared with short‐term use. Long‐term and short‐term users did not differ in background data. Continued use of aversive drugs after the first 6 months might have been critical for favourable outcome.
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| 6. |
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| 7. |
- Berglund, Johan, et al.
(författare)
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Reaction of Peroxomonosulfate Radical with Manganese(II) in Acidic Aqueous Solution. A Pulse Radiolysis Study
- 1994
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Ingår i: Journal of the Chemical Society - Faraday Transactions. - : Royal Society of Chemistry (RSC). - 0956-5000 .- 1364-5455. ; 90:21, s. 3309-3313
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Tidskriftsartikel (refereegranskat)abstract
- The reaction between the SO5– radical and MnII has been proposed to be the most important process for regeneration of MnIII in the MnIII/II-catalysed autoxidation of SIV in acidic aqueous solution. In the present study, the second-order rate constant for this reaction has been determined at pH 3. 0 and 10 mmol dm–3 ionic strength by use of pulse radiolysis. The study was performed in the presence of excess SIV. Under these conditions MnII is distributed among the complexes Mn2+(aq), [Mn(HSO3)]+ and [Mn(SO3)Mn]2+. The rate of reaction decreases as a function of increasing [MnII]total which is rationalized qualitatively by a mechanism involving three parallel reactions between SO5– and the MnII complexes, with rate constants k16, k17 and k18, respectively. Mn2++ SO5– [graphic omitted] Mn3++ HSO5–(16), [Mn(HSO3)]++ SO5– [graphic omitted] [Mn(HSO3)]2+ HSO5–(17), [Mn(SO3)Mn]2++ SO5– [graphic omitted] [Mn(SO3)Mn]3++ HSO5–(18), For increasing total concentrations of MnII, formation of the sulfito-bridged complex is favoured which implies that k18 < k16, k17. Values of the second-order rate constant in the range 2 × 10 108–2 × 1010 dm3 mol–1 s–1 have been determined, depending on which MnII species is predominant. Subsequent slow processes are observed following the formation of MnIII. These reactions have been attributed to the disproportionation of MnIII and reactions between the MnIII species and excess SIV. The implications of the present results for the MnIII/II catalysed autoxidation of SIV are discussed.
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| 8. |
- Berglund, Lars A., et al.
(författare)
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Effect of intralaminar toughness on the transverse cracking strain in cross-ply laminates
- 1991
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Ingår i: Advanced Composite Materials. - 0924-3046 .- 1568-5519. ; 1:3, s. 225-234
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Tidskriftsartikel (refereegranskat)abstract
- The effect of toughness on the onset of transverse cracking was studied in [0m/90n]s cross-ply laminates. Experimental observations indicated that carbon fiber composites based on tougher matrices show weaker constraint effect although their mechanical cracking strain improves in the low constraint region. From LEFM theory it was predicted that the total transverse cracking strain in a thick 90-deg layer of a cross-ply laminate is 1 . 58 times higher than the transverse failure strain of the unidirectional composite. This was verified by experimental data. The LEFM-based model by Isida was applied to the transverse cracking problem in order to predict the total transverse cracking strain for different cross-ply laminates. Model predictions showed good agreement with experimental data for the brittle matrix T300/934 carbon fiber composite. However, for carbon fiber composites the predictions did not describe the experimentally observed weakening of the constraint effect with increasing toughness.
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| 9. |
- Berglund, Lars A., et al.
(författare)
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Fracture of epoxies subjected to uniaxial and triaxial stress fields
- 1994
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Ingår i: Deformation, yield and fracture of polymers. - : Institute of Materials.
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Konferensbidrag (refereegranskat)abstract
- The uniaxial fracture properties of dogbone specimens are often used to estimate the performance of polymers in other loading situations, e.g. composite matrices. Although triaxial stress states are likely to affect the fracture behavior, this effect is difficult to quantify. In the present study, a method previously used for rubbers (the poker-chip method) was used to subject epoxies to a triaxial tension stress field. The method was successfully used and its validity supported by stress analysis and fractography. Results showed the fracture behavior of the poker-chip specimen to be dramatically different compared to the uniaxial case. A general decrease in strain to failure was observed for the triaxial test data. Yield criteria, shown to predict yielding in epoxies for biaxial stress states, suggest some other mechanism to control failure of the poker-chip specimen
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| 10. |
- Berglund, Lars A., et al.
(författare)
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Transverse Cracking and Local Delamination in [04/90n]s and [90n/04]s Carbon Fiber/Toughened Epoxy Laminates
- 1992
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Ingår i: Journal of reinforced plastics and composites (Print). - : SAGE Publications. - 0731-6844 .- 1530-7964. ; 11:6, s. 643-660
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Tidskriftsartikel (refereegranskat)abstract
- [04/90n]s and [90n/04 ]s laminates were used to study 90°-layer failure mechanisms in HTA/6376 carbon fiber/toughened epoxy. The different stacking sequences were chosen to vary the stress states, since experimental results show differences in failure strains as well as in the local delamination behavior at the crack tip. Differences in the onset of transverse cracking and local delamination behavior between [04/90m]s and [90 n/04]s laminates was discussed using a model based on linear elastic fracture mechanics (LEFM). Although quantitative LEFM-predictions do not agree with data for the carbon fiber/toughened epoxy investigated, the general predictions for differences in and causes of local delamination behavior were confirmed by experimental data. The fact that the main features were correctly predicted, encourages the development of some modified LEFM-approach to describe toughened matrix composites.
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