| 1. |
- Almgren, Karin, et al.
(författare)
-
Role of fibre-fibre and fibre-matrix adhesion in stress transfer in composites made from resin-impregnated paper sheets.
- 2009
-
Ingår i: International Journal of Adhesion and Adhesives. - : Elsevier BV. - 0143-7496 .- 1879-0127. ; 29:5, s. 551-557
-
Tidskriftsartikel (refereegranskat)abstract
- Paper-reinforced plastics are gaining increased interest as packaging materials, where mechanical properties are of great importance. Strength and stress transfer in paper sheets are controlled by fibre-fibre bonds. In paper-reinforced plastics, where the sheet is impregnated with a polymer resin, other stress-transfer mechanisms may be more important. The influence of fibre-fibre bonds on the strength of paper-reinforced plastics was therefore investigated. Paper sheets with different degrees of fibre-fibre bonding were manufactured and used as reinforcement in a polymeric matrix. Image analysis tools were used to verify that the difference in the degree of fibre-fibre bonding had been preserved in the composite materials. Strength and stiffness of the composites were experimentally determined and showed no correlation to the degree of fibre-fibre bonding, in contrast to the behaviour of unimpregnated paper sheets. The degree of fibre-fibre bonding is therefore believed to have little importance in this type of material, where stress is mainly transferred through the fibre-matrix interface.
|
|
| 2. |
- Almgren, P
(författare)
-
Tvärkraftsbelastade spikar i ändträ provningsrapport
- 1987
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Provningar för dimensionering av olika konstruktioner kräver tid och omtanke. I dagens byggnorm, SBN 1980, finns inga angivna tillåtna värden för spikar i ändträ, varken när det gäller utdragskraft eller tvärkraft. I praktiken utnyttjas ofta spikar i ändträ för att ta upp tvärkraften. Man vet av erfarenhet att det ger en avsevärd hållfasthet åt förbanden. Ingen riktig dokumentation av hur stor hållkraften är har dock funnits. En inledande studie har nu gjorts av spikars hållkraft i ändträ. Det karakteristiska värdet (ett av hållfasthetsspridningen påverkat fraktilvärde, lägre än medelvärdet) för spik i ändträ visade sig kunna sättas till ca 60 % av motsvarande värde för spik slagen vinkelrätt fibrerna. Värdet kan dock inte anges utan förbehåll innan ytterligare studier gjorts och regler för hur provningen skall utföras utarbetats.
|
|
| 3. |
- Kadi, M., et al.
(författare)
-
Mixed micelles of fluorocarbon and hydrocarbon surfactants. A small angle neutron scattering study
- 2004
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 20:10, s. 3933-3939
-
Tidskriftsartikel (refereegranskat)abstract
- Mixtures of the partly fluorinated cationic surfactant HFDePC (N-(1, 1,2,2-tetrahydroperfluorodecanyl)pyridinium chloride and deuterated headgroup) with C(16)TAC, hexadecyl-trimethylammonium chloride, have been investigated using small angle neutron scattering with contrast matching. Earlier results from this system suggested that a demixing occurred, into two coexisting populations of micelles, hydrocarbon-rich and fluorocarbon-rich, respectively. The present results could be explained by one type of mixed micelles with an inhomogeneous distribution of fluorinated and hydrogenated surfactants within the micelles although a demixing cannot be definitely excluded.
|
|
| 4. |
- Mays, H, et al.
(författare)
-
Spontaneous formation of reverse vesicles with soybean phosphatidyl ethanolamine in mixture with triglyceride and some water
- 1999
-
Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 15, s. 8072-8079
-
Tidskriftsartikel (refereegranskat)abstract
- Mixing the phospholipid soybean phosphatidyl ethanolamine (PE) with the triglyceride triolein and a trace amount of water leads to a spontaneous formation of isotropic aggregates. Evidence for the existence of such aggregates in pseudo-three-component systems is presented here for the first time. Dynamic light scattering and cryogenic temperature transmission electron microscopy reveal polydisperse spherical particles with radii in the range of 250-840 nm and a mean radius of the order 600 nm. From the results of both depolarized light scattering and time-resolved electro-optical birefringence (Kerr effect) the presence of aggregates with an optical anisotropy (rodlike or wormlike reverse micelles as well as particles with lamellar structure) can be excluded. The remaining possibilities are reverse vesicles and a dispersed cubic bicontinuous phase, where our results favor reverse vesicles. A necessary condition for the formation of reverse vesicles is a saturation of the PE-triolein mixture with water; at lower water content the particles are significantly smaller.
|
|
