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- Håkansson, H., et al.
(författare)
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In vivo and in vitro toxicity of fractionated fish lipids, with particular regard to their content of chlorinated organic compounds
- 1991
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Ingår i: Pharmacology and Toxicology. - : Wiley. - 0901-9928 .- 1600-0773. ; 69:6, s. 459-471
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Tidskriftsartikel (refereegranskat)abstract
- Six different lipid matrices (the intact lipid (IL), four lipid fractions with different polarity, and the free fatty acids (FFAs) obtained by hydrolysis of the triacylglycerol (TAG) containing fraction) were obtained from salmon (Salmo salar) and eel (Anguilla anguilla), each collected at a contaminated and a comparatively uncontaminated catch site along the coast of Scandinavia. The lipid matrices were studied in toxicological test systems representing various biological functions of different organ systems from several species and trophic levels. The results were evaluated with particular respect to the concentrations of extractable organically bound chlorine (EOCl) in the matrices tested. In some test systems, the specimens with a higher EOCl concentration appeared to be more toxic. For example, the TAG containing fraction (F2) from Idefjord eel, having a higher EOCl content than F2 from Oslofjord eel, reduced the number and hatchability of eggs laid by zebrafish. Both IL and F2 of Idefjord eel increased mortality and reduced the oxygen/nitrogen-ratio in blue mussels. Non-polar compounds (F1) from Bothnian Sea salmon induced 7-ethoxyresurofin O-deethylase (EROD) activity in rainbow trout hepatocytes, whereas F1 from Senja salmon did not. F1 from Bothnian Sea salmon also reduced the number of T-cells in foetal mouse thymus anlagen in vitro compared with the cell number in anlagen exposed to F1 from Senja salmon. A positive correlation between EOCl concentration and test response was found for EROD activity in rainbow trout hepatocytes and for ATP-leakage in Erlich ascites tumour cells when testing the phospolipid containing fraction (F4). However, in most test systems the fish oils, irrespective of EOCl content, were of low toxicity, and the observed effects need to be verified in future studies.
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- Mäntylä, P., et al.
(författare)
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Improved thickness and shape accuracy with advanced pass scheduling in plate rolling
- 1992
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Ingår i: Journal of Materials Processing Technology. - : Elsevier BV. - 0924-0136 .- 1873-4774. ; 34, s. 255-263
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Tidskriftsartikel (refereegranskat)abstract
- The so-called CROWN programs have been developed as a result of the co-operation in the Scandinavian Steel Industry. They consist of separate physical models for calculation of plate or strip temperature and roll thermal expansion, wear and elastic deformation. Flatness and residual stresses in the material are deduced from the relative change in profile during rolling with the aid of a shape vector method which considers the transverse metal flow in the roll gap. The CROWNON model is an on-line model which can be used for process control in rolling mills. A new optimized pass schedule generation system has been developed for the plate mill in Rautaruukki. The pass schedule is calculated in the forward direction for the sizing pass, broadside passes and the longitudinal passes. The drafts for the broadside and the first longitudinal passes are limited by maximum force, torque and strain. For the last longitudinal passes, the shape vector method is applied and the draft is restricted by the maximum steepness and flatness criteria. The change in the relative elongation differences between the centre and the edge of the plate together with experimentally determined values for the transverse metal flow (e.g. ξ-values) are used in the schedule calculation. To predict correct rolling loads during the scheduling, an adaptive temperature-dependant force-draft model is used based on statistical analysis of the rolling process. The system has decreased the number of passes, improved the yield and has provided the possibility of rolling thin, wide plates, e.g. 4.7 × 3250 mm with good flatness and minimum crown. The barrel length of Rautaruukki's plate mill is 3,6 m and the maximum rolling speed is 5 m/s. During the last years two dimensional and three dimensional Finite Element simulations of hot rolling of flat products have been made. The calculated rolling forces show very good agreement with experiments made in Rautaruukki's plate mill. © 1992.
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