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- An, Li, 1955
(författare)
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Load Bearing Capacity and Behaviour of Composite Slabs with Profiled Steel Sheet
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In many cases the capacity of composite slabs with profiled steel sheeting depends on the shear resistance at the sheet-concrete interface. This shear resistance is essential to the interaction between the steel sheeting and the concrete. Besides this, other factors also affect the behaviour of composite slabs. The first aim of this study is to find an effective method to measure the shear resistance at the concrete-sheet interface. Secondly, it aims to study the influence of different parameters on the load bearing capacity and behaviour of composite slabs without performing a large number of full-scale tests. The behaviour of composite slabs was investigated experimentally. A small-scale test, the concrete block bending test, was developed to measure the shear resistance at the concrete-sheet interface. The obtained shear flow-slip relation was then used in a numerical simulation using the finite element method. Moreover, six full-scale composite slabs with profiled steel sheet PEVA 45 were tested to determine the shear capacity of the slabs. The test results were evaluated according to the Swedish code and were used for comparison with the results from numerical simulations. A two-dimensional finite element model was used to study the behaviour of one-way composite slabs. It was found that the concrete strength only slightly affected the capacity of the slabs. The horizontal shear resistance at the sheet-concrete interface and the strength of the steel sheet were the most important factors. It was also found that the actual influence of horizontal shear resistance and the strength of the steel sheet depended on the failure modes of the slabs. Comparatively, the resistance for vertical separation had little effect and the influence can be neglected in the analysis. The behaviour of two-way composite slabs which were simply supported at four edges were investigated by a three-dimensional finite element model. It was found that the load transferred in two directions depended on a span to span ratio of the slabs. Compared with one-way slabs, two-way composite slabs had the advantages of a small deflection, a small end-slip and a high capacity.
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- Babushkin, Oleg, et al.
(författare)
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Thermal expansion of hot isostatically pressed hydroxyapatite
- 1994
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 4:3, s. 413-415
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Tidskriftsartikel (refereegranskat)abstract
- A dense and transparent hydroxyapatite produced by hot isostatic pressing was investigated with respect to its stability and thermal expansion behaviour in the range 20–1150 °C. The evaluation was made by high-temperature X-ray diffraction in a reconstructed test chamber with a BN sample holder and Pt as an internal (in situ) reference. No degradation of the hydroxyapatite was detected in the range investigated. The lattice parameters, a and c, were determined as a function of temperature. The linear thermal expansion coefficient, determined by dilatometry, was 17.1 × 10–6°C–1, which agreed well with the value 17.3 × 10–6°C–1 obtained by X-ray diffraction.
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| 4. |
- Baeckstroem, P., et al.
(författare)
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Convenient Method for the Synthesis of Lineatin, a Pheromone Component of Trypodendron-Lineatum
- 1991
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 56:10, s. 3358-3362
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Tidskriftsartikel (refereegranskat)abstract
- Synthesis of racemic lineatin (1), a pheromone component of Trypodendron lineatum, is described. Condensation of 5-methyl-5-hexen-2-one (2) and triethyl phosphonoacetate with LiN(SiMe3)2 gave esters 3, which upon hydrolysis gave acids 4a-f. The bicyclo[3.2.0] ring compounds 5 and 6 were obtained via an intramolecular [2 + 2] addition by refluxing underivatized carboxylic acids 4a-f with NaOAc and Ac2O. Compound 5 was isomerized to the thermodynamically more stable isomer 6 using a Pd/C catalyst activated with hydrogen. Reduction of 6 with LiAlH4 gave the endo and exo isomers 7a and 7b (4:1). Isolation of the alcohol 7a followed by acetylation gave 8. Subsequent oxidation with OsO4 and methylmorpholine N-oxide gave diol 9. Cleavage of 9 with H5IO6 in diethyl ether gave keto aldehyde 10, which was converted to keto acetal 11. Treatment of 11 with MeMgBr followed by acidic workup gave 1. The overall efficiency is approximately 20%.
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- Bennich-Björkman, Li, et al.
(författare)
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A creative university: is it possible?
- 1991
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Ingår i: Studies of higher education and research, 1991:4. ; 1991:4
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Forskningsöversikt (refereegranskat)
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| 7. |
- Bennich-Björkman, Li, 1960-
(författare)
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Den lilla världens stora makt
- 1993
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Ingår i: Tiden. - Stockholm : Sveriges socialdemokratiska arbetareparti. - 0040-6759. ; :3, s. 49-53
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Recension (populärvet., debatt m.m.)
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