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- Fällström, Karl-Evert, et al.
(författare)
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Transient bending waves in anisotropic plates studied by hologram interferometry
- 1989
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Ingår i: Experimental mechanics. - 0014-4851 .- 1741-2765. ; 29:4, s. 409-413
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Tidskriftsartikel (refereegranskat)abstract
- Propagating bending waves are studied in plates made of glass-fiber reinforced polyester. The waves are generated by the impact of a ballistic pendulum. Hologram interferometry, with a double pulsed ruby laser as light source, is used to record the out of plane motion of the waves. The interferograms have an elliptic-like symmetry for an orthotropic plate, while the wave pattern for a symmetric angle-ply reinforced plate has a symmetry about the axes of reinforcements. Experimental data are compared on one hand to analytical results obtained by assuming that the orthotropic plate can be described as if isotropic along the main axes, and on the other hand to numerical results from calculations using the finite-element method. The effective Young's modulus raised to power 1/4 is shown to be an important parameter for the description of the dispersive wave pattern. A defect in the plate alters the wave pattern in the interferograms significantly. This may have technical use.
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| 2. |
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| 3. |
- Heijl, A, et al.
(författare)
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Visual field interpretation with empiric probability maps
- 1989
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Ingår i: Archives of Ophthalmology. - : American Medical Association (AMA). - 0003-9950. ; 107:2, s. 8-204
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Tidskriftsartikel (refereegranskat)abstract
- Automated visual field charts may be difficult to interpret partly because of the magnitude and complex nature of normal threshold variability. We devised two types of empiric probability maps in which this variability is taken into account and the significances of measured threshold values are displayed. These maps are highly sensitive to nonobvious but significant paracentral field loss but will at the same time deemphasize false-positive patterns commonly found more peripherally. They also frequently show field defects before these are obvious in conventional threshold printouts. In addition, they differentiate between generalized loss of sensitivity and localized field defects.
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| 4. |
- Kaspersson, A., et al.
(författare)
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Microbial dynamics in barley grain stored under controlled atmosphere
- 1988
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Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 19:4, s. 299-312
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Tidskriftsartikel (refereegranskat)abstract
- Barley of 2 moisture contents, 20-23% and 26-28%, was stored airtight for 2 separate seasons in 2 full-scale silos, and for 3 separate seasons in 12-16 pilot silos (1.25 m3). The microbial dynamics were studied, using colony-forming units (CFU) of microorganisms, the proportion of internally-invaded kernels and ATP content. The ATP content was a good measure of the microbial activity, which decreased after loading and was very low during the winter period. Field-associated moulds and yeasts decreased in numbers of CFU and in the amount of invaded kernels. Fusarium species survived more satisfactorily than most field fungi. The temperature rise in spring caused an increase in ATP content, as a result of extensive growth of yeast of the genera Hansenula and Candida. This activity started earlier in the high-moisture grain (March). In May, a significant increase in CFU of Penicillium was observed and, during May to July, in many silos, all kernels were invaded, mostly by P. roqueforti. In an attempt to increase the time of safe storage, some technical improvements and gaseous and liquid chemical additives were tested. Attachment of "lungs" to the silos, and addition of organic acids or gases (CO2, N2, NH3) to the grain, increased the safe storage time by one to several months. The aerobic storage stability of rolled barley taken in July from the full-scale silos was tested. The rapid deterioration following unloading limited the aerobic storage stability to a few days. © 1988.
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