| 11. |
- Adamopoulos, Stergios, et al.
(författare)
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Dimensional changes of extracted and non-extracted small wood specimens of black locust (Robinia pseudoacacia L.)
- 2003
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Ingår i: European Journal of Wood and Wood Products. - : Springer. - 0018-3768 .- 1436-736X. ; 61:4, s. 264-268
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Tidskriftsartikel (refereegranskat)abstract
- From straight grained heartwood of black locust (Robinia pseudoacacia L.), specimens, 3 cm×3 cm in cross section and 0.5 mm (or 10 mm) in axial direction, were cut and used for the determination of dimensional changes and the rate of tangential swelling. Mean radial, tangential and axial shrinkage was 5.30%, 6.67% and 0.16%, respectively, while the coefficient of anisotropy was 1.26. Half of the specimens for the determination of the rate of tangential swelling were extracted for 48 h with distilled hot water. The tangential dimensional change and the time taken to attain half maximum swelling in air-dry and oven-dry specimens were assessed according to a common technique. Extractive removal resulted in an increase of the total magnitude of tangential swelling in both air-dry and oven-dry specimens. However, no significant differences in time taken to attain half maximum swelling between air-dry and oven-dry specimens were observed after extraction. The rate of tangential swelling was lower in air-dry specimens than in oven-dry specimens after 30 min of immersion in water when were non-extracted and after 5 min of immersion in water when were extracted. Extracted air-dry specimens had a greater rate of tangential swelling than non-extracted air-dry specimens and the same occurred for oven-dry specimens. Extraction resulted in a higher diffusion coefficient for air-dry specimens. The diffusion coefficient calculated for non-extracted air-dry specimens (0.901×10−4 cm2/min) showed that black locust is a difficult species to impregnate.
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| 12. |
- Adamopoulos, Stergios
(författare)
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Flexural properties of black locust (Robinia pseudoacacia L.) small clear wood specimens in relation to the direction of load application
- 2002
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Ingår i: European Journal of Wood and Wood Products. - : Springer. - 0018-3768 .- 1436-736X. ; 60:5, s. 325-327
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Tidskriftsartikel (refereegranskat)abstract
- Values of pure moduli of elasticity (PMOE), experimental modulus of elasticity (MOE) in static bending and moduli of rigidity (GLR, GLT) were calculated in juvenile and mature black locust defect-free small wood specimens after loading in static bending alternately on true radial and tangential surfaces. For both juvenile and mature specimens, no significant differences (t-test, 95% probability level) were found between the radial and tangential moduli of elasticity and rigidity. Values of PMOE were found to be 27–32% higher than the corresponding values of MOE at the 15:1 span-to-depth ratio.
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| 13. |
- Adamopoulos, Stergios
(författare)
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Influence of hot-water extractives on radial and tangential shrinkage of black locust wood (Robinia pseudoacacia L.)
- 2002
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Ingår i: European Journal of Wood and Wood Products. - : Springer. - 0018-3768 .- 1436-736X. ; 60:5, s. 377-378
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionRemoval of extractives increases the shrinkage and swelling of wood (Nearn 1955, Salamon and Kozak 1968, Cooper 1974, Taylor 1974). The effect of progressive extraction on the above properties has not been investigated much. In oak (Quercus conferta L.), a forest species rich in extractives, the shrinkage progressively increased with progressive extraction (Voulgaridis et al. 1980). In black locust (Robinia pseudoacacia L.), much of the main-stem volume is comprised of heartwood, characterized by the presence of dark yellow-brown extractives. While the extractives of black locust give the heartwood its distinctive color and decay resistance, they comprise only 6.2 to 8.3% of the dry weight of the main stem (Stringer 1992). Hot-water extractives range from 5.2 to 8.6% (Hart 1968, So et al. 1980). The present study was primarily undertaken to determine whether the progressive removal of hot-water extractives affects the radial and tangential shrinkage of black locust heartwood.
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| 14. |
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| 15. |
- Adamopoulos, Stergios, et al.
(författare)
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Within-tree variation in growth rate and cell dimensions in the wood of black locust (Robinia pseudoacacia)
- 2002
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Ingår i: IAWA Journal. - : Brill Academic Publishers. - 0928-1541 .- 2294-1932. ; 23:2, s. 191-199
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Tidskriftsartikel (refereegranskat)abstract
- Black locust (Robinia pseudoacacia L.) is regarded as an important natural resource almost throughout the world but relatively little is known about the within-tree variability of the anatomical characteristics of its wood. Discs 2 cm thick were cut at 2.25 m intervals, from the ground level to the top from ten black locust trees, 18–37-years-old, from the University Forest of Taxiarchi, Chalkidiki, Greece. The discs were used for the determination of growth rate and cell dimensions (fiber length and vessel member length and diameter) and their withintree variability (radial, oblique, vertical). Growth rate increased within the first 5–9 growth rings from the pith and then gradually decreased. Oblique variation of growth rate did not exhibit any clear tendency but a decrease at the top. In the case of vertical variation, growth rate decreased gradually with the year of cambium formation. Radial variability curves were found to be typical for the dimensions of cells (fibers, vessel members) especially for the fiber length. A rapid increase in cell dimensions was observed in the first 7–11 growth rings, the juvenile zone. Oblique and vertical variation of cell dimensions did not exhibit any clear tendencies.
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| 16. |
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| 17. |
- Arkbåge, Karin, et al.
(författare)
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Bioaccessibility of folic acid and (6S)-5-methyltetrahydrofolate decreases after the addition of folate-binding protein to yogurt as studied in a dynamic in vitro gastrointestinal model.
- 2003
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Ingår i: Journal of Nutrition. - 0022-3166 .- 1541-6100. ; 133:11, s. 3678-3683
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Tidskriftsartikel (refereegranskat)abstract
- Milk products are only moderate sources of folate. Nevertheless, they are of interest due to their content of folate-binding proteins (FBP), which in some studies have been reported to increase folate bioavailability. The effect of FBP on folate bioavailability has been widely discussed. The aim of this study was to investigate the bioaccessibility of folic acid and (6S)-5-methyltetrahydrofolate (5-CH3-H4folate) from fortified yogurt using a dynamic in vitro gastrointestinal model (TIM). In addition, the effect of FBP on folate bioaccessibility and the stability of FBP added to yogurt during gastrointestinal passage were investigated. Folate bioaccessibility was 82% from yogurt fortified with folic acid and 5-CH3-H4folate. The addition of FBP to yogurt decreased (P < 0.05) folate bioaccessibility. The lowering effect of FBP was more pronounced in yogurt fortified with folic acid (34% folate bioaccessibility) than from yogurt fortified with 5-CH3-H4folate (57% folate bioaccessibility). After gastrointestinal passage, 17% of the FBP in yogurt fortified with 5-CH3-H4folate and 34% of the FBP in yogurt fortified with folic acid were recovered. No difference in folate bioaccessibility was found between folate-fortified yogurt and folate-fortified pasteurized milk (P = 0.10), whereas the lowering effect of FBP was (P < 0.05) greater in yogurt compared with pasteurized milk. In conclusion, based on the high bioaccessibility of folic acid and 5-CH3-H4folate, yogurt without active FBP can be considered to be an appropriate food matrix for folate fortification.
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| 18. |
- Arkbåge, Karin, et al.
(författare)
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Retention of vitamin B-12 during manufacture of six fermented dairy products using a validated radio protein-binding assay
- 2003
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Ingår i: International Dairy Journal. - 0958-6946 .- 1879-0143. ; 13:2-3, s. 101-109
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to study vitamin B-12 retention during manufacture of six fermented dairy products. Careful validation of a commercial radio protein-binding kit showed this assay to be suitable after optimisation of sample pre-treatment and control of the kit for possible matrix effects. In fermented milks, vitamin B-12 concentrations decreased by 40-60%, compared with the starting milk, during storage of the final product at 4degreesC for 14 days, most likely attributed to consumption by starter cultures. In cottage cheese, hard cheeses and blue cheese, 18-56% of the vitamin B-12 originally present in the milk was retained. Removal of the whey fraction was the dominant factor reducing vitamin B-12 retention in cheeses, while the fermentation by starter cultures hardly affected vitamin B-12 concentrations.
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| 19. |
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| 20. |
- Blennow, Kristina, et al.
(författare)
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Evaluating WINDA : a tool for assessing the probability of wind damage to forest stands
- 2003
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Ingår i: Proceedings of the International Conference Wind Effects on Trees. ; , s. 137-144
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- WINDA is an integrated system of models for calculating the stand-wise probability of wind damage of trees within a landscape (Blennow & Sallnäs, submitted). It integrates a modified version of the dose/response model HWIND (Peltola et al., 1999), the airflow model WASP (Mortensen et al., 1998), and a component for calculating the zero-plane displacement and surface roughness. WINDA uses a GIS for geographical computations. The calculations are made point-wise at exposed stand edges and the results are combined for each stand. The likelihood of damage is calculated using extreme value theory. The mechanistic modelling approach makes WINDA useful for evaluating effects on the probability of wind damage of silvicultural treatments and forestry activities as well as of a changed climate. This paper briefly outlines WINDA and evaluates output by comparing predicted damage with observed damage for two landscapes in southern Sweden.
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