| 1. |
- Berndtsson, Bo, 1950
(författare)
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Bergman kernels for Paley-Wiener spaces and Nazarov’s proof of the Bourgain-Milman theorem
- 2022
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Ingår i: Pure and Applied Mathematics Quarterly. - 1558-8599 .- 1558-8602. ; 18:2, s. 395-409
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Tidskriftsartikel (refereegranskat)abstract
- We give a general inequality for Bergman kernels of Bergman spaces defined by certain convex weights in Cn. We also discuss how this can be used in Nazarov’s proof of the BourgainMilman theorem, as a substitute for Hörmander’s estimates for the ¯∂-equation.
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| 2. |
- Lechner, Thomas, 1979, et al.
(författare)
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Assessment of Density in Timber Using X-Ray Equipment
- 2013
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Ingår i: International Journal of Architectural Heritage. - : Informa UK Limited. - 1558-3058 .- 1558-3066. ; 7:4, s. 416-433
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Tidskriftsartikel (refereegranskat)abstract
- Wood density has a strong relationship with several mechanical properties, such as strength and stiffness. An x-ray image calibration procedure, which enables the determination of density properties for the in situ assessment of timber structures, has been developed. This nondestructive method is useful for evaluating the internal condition for global assessments of the structure. For this study, 14 wood specimens with significant density differences were exposed to x-rays. The specimens were set up in a number of image configurations. The images were analyzed and evaluated using an image toolbox. A similar procedure was applied to six built-up blocks with different thicknesses in order to calibrate the thickness of the specimens. Finally, a calibration wedge was set up to verify the procedure. The density calibration procedure from x-ray images was verified on a timber beam specimen, resulting in good agreement and an average accuracy of 97%. The values obtained from the image calibration presented a very good linear correlation between the measured density and the grayscale from x-ray images with coefficients of determination (R-2) ranging from 0.90-0.98. The main advantages compared with conventional techniques are the detection and quantification of internal damage, defects, disturbances, and deterioration that may reduce the mechanical properties of the structure. This study shows good potential when it comes to the development of a viable tool for in situ assessments of timber structures. This technique could be used indirectly in analyses of structural behavior.
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| 3. |
- Gubanski, Stanislaw, 1950, et al.
(författare)
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Ageing of Silicone Rubber Insulators in Coastal and Inland Tropical Environment
- 2010
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Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - 1558-4135 .- 1070-9878. ; 17:2, s. 326-333
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents investigations on the performance of 33 kV silicone rubber insulators characterized by different creepage lengths, which aimed to find out whether the insulators could permanently work when electrically stressed beyond the recommended limits in polluted and clean tropical environments. The study was performed under natural field and laboratory conditions. The insulators tested included eight types of silicone rubber composite insulators, one type of hybrid silicone-ceramic insulator and one semi-conducting glazed porcelain insulator, while ordinary porcelain and glass insulators were used as reference. During the field investigation, two sets of the insulators were separately installed and energized in coastal and inland parts of Sri Lanka, being by that exposed to marine and clean tropical environments. Their performances were periodically evaluated by visual inspections and measurements of hydrophobicity class. After five years of field exposure, the insulator performances were evaluated in laboratory by measurements of leakage currents under clean fog conditions and of wet flashover voltage. A third set of the insulators was aged in laboratory for 1000 hours inside a salt fog chamber where the insulators were continuously energized and daily sprayed with salt solution for eight hours and left to rest for remaining 16 hours. This treatment represented conditions similar as those in the field i.e. insulators exposed to salt sprays during monsoons. The insulator performances were investigated by measurements of leakage currents and classifying their patterns into different categories, i.e. capacitive, resistive, non-linear, discharge and strong discharge types, by means of fast Fourier transform and short time Fourier transform analyses. It was found that the long-term field exposure yielded weaker insulator deterioration than the salt fog chamber ageing, which indicated for a possibility to increase the electric stress on silicone rubber insulators to levels higher than the ones used today on glass and porcelain counterparts.
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| 4. |
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| 5. |
- Gubanski, Stanislaw, 1950
(författare)
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Editorial
- 2011
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Ingår i: IEEE Electrical Insulation Magazine. - 0883-7554 .- 1558-4402. ; 27:2, s. 4-5
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Gubanski, Stanislaw, 1950
(författare)
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Editorial- Outdoor High Voltage Insulation
- 2010
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Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - 1558-4135 .- 1070-9878. ; 17:2, s. 325-
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Gubanski, Stanislaw, 1950, et al.
(författare)
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FROM THE EDITORS' DESK
- 2018
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Ingår i: IEEE Electrical Insulation Magazine. - 0883-7554 .- 1558-4402. ; 34:6, s. 6-7
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 8. |
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| 9. |
- Hassel, Lars, 1950-, et al.
(författare)
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Psychic distance and budget control of foreign subsidiaries
- 2004
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Ingår i: Journal of International Accounting Research. - : American Accounting Association. - 1542-6297 .- 1558-8025. ; 3:2, s. 79-93
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Tidskriftsartikel (refereegranskat)abstract
- This paper has two purposes: (1) to develop a theory about the impact of psychic distance on management control of multinational companies, and (2) to establish that psychic distance is an important factor for future research. We develop the concept of psychic distance, the interaction between geographic distance and culture, and test its impact empirically in a Finnish multinational company.Results show that psychic distance interacts significantly with reliance on budget control in multinational companies, but not in the manner proposed. High budget emphasis is associated with high subunit performance in countries with small psychic distances, but not in countries with larger psychic distances. Budget participation dilutes this impact. This study confirms that psychic distance is a relevant factor to be considered in future research.
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| 10. |
- Janlert, Lars-Erik, 1950-
(författare)
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The ubiquitous button
- 2014
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Ingår i: interactions. - : Association for Computing Machinery (ACM). - 1072-5520 .- 1558-3449. ; 21:3, s. 26-33
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Tidskriftsartikel (refereegranskat)abstract
- Why are buttons so common in contemporary artifacts and yet so often a source of irritation and trouble? Could we, by reinstating the natural mode of operation with traditional mechanical systems, dispel our confusions and remedy our confirmation deficiencies? Probably not.
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