| 11. |
- Löfgren, Lars, 1964, et al.
(författare)
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Selective assessment of C2-C6 alkenes in air by adsorption sampling and gas chromatography
- 1991
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Ingår i: Journal of environmental analytical chemistry. ; 45, s. 39-44
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Tidskriftsartikel (refereegranskat)abstract
- A system is described for the specific determination in air of ethene, propene, the four isomeric butenes, cyclopentene and the six isomeric pentenes. The butenes, pentenes and hexenes are well separated from the commonly occurring matrix of alkanes in much higher concentrations. Field samples were taken using easily carried equipment consisting of an air pump connected to an adsorbent cartridge. An advantageous combination of triple-layer adsorbents was found to be Tenax + Carbotrap + Carbosieve S-III. In the laboratory, the hydrocarbons were thermally desorbed into a cold trap. The trap was directly linked to the aluminium oxide PLOT column which effected the alkene separations.
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| 12. |
- Petersson, Göran, 1941, et al.
(författare)
-
Hazardous petrol hydrocarbons from refuelling with and without vapour recovery
- 1990
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Ingår i: The science of the total environment. ; 91, s. 49-57
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Tidskriftsartikel (refereegranskat)abstract
- Hydrocarbons in air were determined at pioneering European service stations equipped with vapour recovery systems. Vapour recovery was found capable of eliminating 99% of exposure during refuelling and greater than 95% of emissions to air. Vapour recovery is now being rapidly introduced at Swedish service stations as a result of demands concerning environmental and health hazards. The analytical technique used permitted samples corresponding to a single refuelling procedure to be analyzed. Sampling on an adsorbent tube was followed in the laboratory by thermal desorption and capillary gas chromatography. All prominent hydrocarbons were well separated on a methylsilicone phase. These include benzene and the alkenes of special interest with respect to health hazards. The particular importance of alkenes with respect to the formation of ozone and other photooxidants is discussed. The four isomeric butenes and the six isomeric pentenes were determined and found to constitute approximately 10% by weight of the petrol vapour. The highly reactive 2-alkenes were more abundant than the 1-alkenes.
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| 13. |
- 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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| 14. |
- Zhang, H., et al.
(författare)
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Interfacial debonding of single fibers in transverse tension
- 1994
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Ingår i: Composite materials, mechanics and processing : September 20 - 22, 1994, John M. Clayton Conference Center, University of Delaware, Newark, Delaware. - : Society of Plastics Engineers. - 1566762200 ; , s. 595-602
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Konferensbidrag (refereegranskat)abstract
- A micromechanical method to measure and analyze interfacial debonding of single fibers in transverse tension was developed. The damage process was observed in-situ by optical microscopy. Two glass fiber/epoxy (GF/EP) systems were studied with different fiber surface treatment. Results from calculations of the interfacial fracture toughness for Mode I and Mode II failure are presented. The theoretical analysis is based on a modification of Toya's stress analysis of a debonded circular inclusion, calculation of the work required to close the crack and a mixed-mode failure criterion
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| 15. |
- 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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