| 1. |
- Schönborg, Niclas, et al.
(författare)
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Impact of DC components in transport current and external magnetic field on hysteresis losses in an HTS tape
- 2004
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Ingår i: IEEE transactions on applied superconductivity (Print). - 1051-8223 .- 1558-2515. ; 14:3, s. 1955-1958
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Tidskriftsartikel (refereegranskat)abstract
- The high-temperature superconductor (HTS) development is presently intensive, and one can expect that HTSs will be used in different electric devices in the future. In some of these devices, e.g., a magnetostrictive actuator, the conductor will be exposed to both ac and dc transport currents and external magnetic fields. One of the most important parameters in the design of electric devices is the power loss. It is, therefore, of importance to develop models that are able to predict the power loss in devices based on HTSs. In this paper, we present an experimental characterization of the hysteresis losses in an HTS tape exposed to ac or dc transport currents in combination with external magnetic fields. The experimental results are compared to some existing models based on the critical state model. The power loss was measured on a multifilamentary Bi-2223 tape at constant temperature (70 K) and frequency (50 Hz).
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| 2. |
- Wass, Torbjörn, et al.
(författare)
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AC losses in applied longitudinal magnetic fields at variable temperatures
- 2004
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Ingår i: IEEE transactions on applied superconductivity (Print). - 1051-8223 .- 1558-2515. ; 14:1, s. 22-27
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Tidskriftsartikel (refereegranskat)abstract
- In most power devices, the conductor is carrying anac transport current while it is exposed to an ac magnetic fieldtransverse to the current path. In certain applications, such aspower cables or a control winding in a controllable reactor, theconductors are exposed to a magnetic field component longitudinalto the tape axis that is parallel to the current path. To createan improved base for the design of such power devices it is ofinterest to study the losses in high-temperature superconductortapes due to longitudinal field in detail. We have investigated thelosses at several temperatures of a nontwisted multifilamentaryBi-2223 tape when it was exposed to a longitudinal magnetic field.The losses were measured with a calorimetric method and theresults were compared with the critical state hysteresis loss model.The hysteresis losses are dominating at power frequencies (50,60 Hz) in the investigated field range 2–200 mT and are accuratelydescribed by the critical state hysteresis model.
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| 3. |
- Wildner, Elena, et al.
(författare)
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Production follow-up of the LHC main dipoles through magnetic measurements at room temperature
- 2004
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Ingår i: IEEE transactions on applied superconductivity (Print). - 1051-8223 .- 1558-2515. ; 14:2, s. 173-176
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we review the tools used for controlling the production of the LHC main dipoles through warm magnetic measurements. For the collared coil measurements, control limits are based on the statistics relative to the pre-series production. For the cold mass, the difference between collared coil and cold mass is considered, allowing a very stringent test. In both cases, measurements are split in straight part average, variations and coil ends contributions. Two different alarm levels exist in case the measured field is out of limits. The analysis can be carried out at the manufacturer and allows detection of anomalies in the measured magnetic field. These can be either due to wrong measurements or caused by assembly defects. Techniques used to work out information on the magnet assembly from the field harmonics are outlined. We summarize the experience gathered on about 180 collared coils and 120 cold masses, pointing out the bad cases and investigating the reliability of the measurements.
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| 4. |
- Gustafsson, Susanne
(författare)
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Flowering frequency in a small population of Gymnadenia conopsea : a five year study
- 2004
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 24:5, s. 599-605
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Tidskriftsartikel (refereegranskat)abstract
- This investigation evaluates the usage of genetic markers, microsatellites, to distinguish and re-identify individual plants in a population of the orchid Gymnadenia conopsea. The study also illustrates the problem in estimating the size of a population from single year sampling as individuals can rest underground or occur in vegetative states; information extremely important for the understanding of population dynamics as well as providing information for conservation management. The total population size was, based on information from microsatellite loci, estimated to 84 individuals and vastly larger than the annual number of flowering plants (mean 31.4 individual s/year). Flowering frequency varied from 24-49%, 53 individuals flowered once, five individuals were flowering four years and a single individual was flowering five years. A common pattern was one or two flowering periods followed by a non-flowering period. The observed number of alleles and the observed and expected heterozygosity varied among loci, although allele frequencies and genotype frequencies did not vary significantly among years.
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| 5. |
- Thulin, Mats
(författare)
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A new genus of Sapindaceae from Somalia
- 2004
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 24:5, s. 509-511
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Tidskriftsartikel (refereegranskat)abstract
- The new genus Hirania (Sapindaceae), with the single species H. rosea from south-central Somalia, is decribed and illustrated. It is a shrub with simple, entire leaves, alternate or crowded on short-shoots, and without stipules. The inflorescences are branched with monochasially arranged, unisexual flowers. The flowers (only male ones known) are zygomorphic with five sepals with gland-tipped hairs along margins, four pink, subequal, clawed petals without appendages, and eight, glabrous stamens. The dark purple disk is narrow and tubular and consists of an upper broader segment partly enclosing a lower narrower segment. The closest relative is believed to be the Australian genus Diplopeltis.
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| 6. |
- Thulin, Mats
(författare)
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A new species of Atriplex (Chenopodiaceae) from Somalia
- 2004
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 24:5, s. 507-508
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Tidskriftsartikel (refereegranskat)abstract
- Atriplex erigavoensis, a new species from gypsum silt in northern Somalia, is described and illustrated. It is distinctive particularly by the dorsal appendages of the female bracteoles that look like an extra pair of small bracteoles.
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| 7. |
- Thulin, Mats
(författare)
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Expansion of Crabbea (Acanthaceae) and the description of two new species from Somalia
- 2004
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 24:5, s. 501-506
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Tidskriftsartikel (refereegranskat)abstract
- Crabbea is expanded to include the monotypic Golaea and Acanthostelma, both endemic in northern Somalia. The new combinations C. migiurtina (=Golaea migiurtina) and C. thymifolia (=Acanthostelma thymifolium) are made and the names are lectotypified. The new species C. pinnatifida and C. albolutea, both endemic in Somalia, are described and illustrated.
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| 8. |
- Thulin, Mats
(författare)
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New species of Tephrosia (Fabaceae) from Somalia and Yemen
- 2004
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 24:5, s. 513-517
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Tidskriftsartikel (refereegranskat)abstract
- The new species Tephrosia flava, from limestone areas in north-eastern Somalia, and T mahrana, from wadis in the deserts of south-eastern Yemen, are described and illustrated.
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| 9. |
- Vaez, Marjan, et al.
(författare)
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Ratings of health and quality of life by young working people : Are there occupational or education-based differences?
- 2004
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Ingår i: Work. - 1051-9815 .- 1875-9270. ; 23:3, s. 193-198
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Tidskriftsartikel (refereegranskat)abstract
- The study examines differences in self-rated health and perceived quality of life (QoL) among young working people according to occupation and education level. Subjects were extracted from a cross-sectional data set, covering questionnaire responses of people aged 20-74 years from the Swedish region of Östergötland, and addressing individual environmental and health conditions. The emphasis was on males and females in paid employment aged 20-34 (n = 863). Differences in self-rated health items and in perceived QoL were subjected to a series of t-tests. Two measures of individual socioeconomic position were considered - occupation and education. No education-based differences were found, and there were few differences based on occupation. Among males, manual workers reported significantly higher scores with regard to pain and physical function than did non-manual workers. Male and female manual workers scored significantly lower on current perceived QoL than non-manual workers. In the case of females, the differences between manual and non-manual workers also applied to former perceived QoL. Yet, after applying the Bonferroni correction, none of the differences observed remained significant. In line with some earlier studies, it appears that - among young working adults - the manners in which health status and QoL are perceived are not strongly conditional on socioeconomic position. © 2004 - IOS Press and the authors. All rights reserved.
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| 10. |
- Borg, Karin, et al.
(författare)
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Prediction of future low levels of sickness absence among young persons sick listed with back, neck, or shoulder diagnoses.
- 2004
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Ingår i: Work (Reading, Mass.). - 1051-9815 .- 1875-9270. ; 23:2, s. 159-67
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Tidskriftsartikel (refereegranskat)abstract
- In recent years sickness absence has increased in most Western countries. Risk factors for sickness absence and disability pension have been emphasised in studies, while focus on factors predicting low sickness absence is very rare. This paper is an attempt to apply such a perspective in an 11-year prospective cohort study of young persons n = 213) who in 1985 were sick listed > or = 28 days with back, neck, or shoulder diagnoses. Having had no sick-leave spells > 14 days in 1992-1996 was used as the outcome measure. Sixty-nine persons (34%) had no such spells, with an unexpected similar proportion of men and women. Data on prior sick leave and demographic variables were analysed using univariate and multiple logistic regression. Factors that predicted low sickness absence were having prior low sickness absence, being a white-collar worker, and being married. We concluded that individuals with a history of low sickness absence have an increased odds for remaining in the work force after a single long sick-leave spell, and might need less attention in rehabilitation compared to persons with a history of high sickness absence. Focusing on low sickness absence led to different results than those discussed in previous studies on risk factors for disability pension.
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