| 1. |
- Ersmark, T., et al.
(författare)
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Influence of geometry model approximations on Geant4 simulation results of the Columbus/ISS radiation environment
- 2007
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487 .- 1879-0925. ; 42, s. 1342-1350
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Tidskriftsartikel (refereegranskat)abstract
- The influence of geometry model approximations on Geant4 Monte Carlo simulation results of the radiation environment on-board the Columbus module of the International Space Station (ISS) has been investigated. Three geometry models of Columbus with different levels of detail and a geometry model of ISS have been developed. These geometries have been used for Geant4 simulations of the radiation environment inside Columbus induced by trapped protons and Galactic Cosmic Ray protons. Simulated dose rates and particle spectra on-board Columbus for each of the three Columbus models, with or without the ISS geometry model included, are presented and compared. From comparisons of simulated dose rates and particle spectra for the three different geometry models it was found that the most detailed geometry model (750 volumes) produced results similar to a much less detailed model (23 volumes). The most detailed geometry model was concluded to be a sufficiently detailed approximation of the physical Columbus for the purpose of proton induced space radiation studies. The simulated dose rates are compatible with measurements on-board the ISS. The simulation results also show that an increase in shielding thickness decreases the simulated dose rate induced by trapped protons. For Galactic Cosmic Ray protons the dose rate remains unchanged or is slightly increased.
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| 2. |
- Kotlov, A., et al.
(författare)
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Excited states of molybdenum oxyanion in scheelite and wolframite structures
- 2007
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487 .- 1879-0925. ; 42:4-5, s. 767-770
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Tidskriftsartikel (refereegranskat)abstract
- Scheelite CdMoO4 and wolframite eCdWO(4):MO (0.04-0.4wt%) single crystals were studied using the time-resolved spectroscopy under UV excitation over a temperature range of 1.85-300K. The threshold energies for the creation of free charge carriers were measured using the method of photostimulated luminescence. The decay kinetics of the main emission in CdMoO4 and the molybdenum-related emission in CdWO4:MO was studied and the parameters of the triplet excited states of molybdenum-related oxyanions were calculated. (C) 2007 Elsevier Ltd. All rights reserved.
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| 3. |
- Lillhök, J E, et al.
(författare)
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A comparison of ambient dose equivalent meters and dose calculations at constant flight conditions
- 2007
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Ingår i: Radiation Measurements. - : Elsevier Ltd. - 1350-4487 .- 1879-0925. ; 42:3, s. 323-333
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Tidskriftsartikel (refereegranskat)abstract
- Ambient dose-equivalent results from an in-flight comparison between different tissue-equivalent proportional counters and silicon diode spectrometers from seven European institutes are presented and compared with calculations using the EPCARD computer program. The measurements were performed on 40 000 and 32 000 ft in narrow target areas at latitudes N57 and N42. Keeping the altitude and geographic position almost constant provided unique conditions for comparisons. The different measuring systems as well as the calculations are in remarkably good agreement, with an average standard deviation in the ambient dose equivalent between 6% and 21%. The ratio between calculated and measured ambient dose-equivalent rates varies between 0.91 and 1.09, with an average of 1.00±0.08 (1s). Nevertheless some systematic differences in the experimentally determined ambient dose equivalent and its low-LET and high-LET components are noticed and discussed. It is concluded that the standard deviation between different instruments can through optimization and harmonization of the calibration procedures be reduced by up to a factor of two.
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| 4. |
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| 5. |
- Vorona, I.P., et al.
(författare)
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The effect of thermal treatment on radiation-induced EPR signals in tooth enamel
- 2005
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487 .- 1879-0925. ; 39:2, s. 137-141
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Tidskriftsartikel (refereegranskat)abstract
- The effect of thermal treatment on the radiation-induced EPR spectrum of tooth enamel was studied. Annealing before sample irradiation was found to increase enamel radiation sensitivity by more than 40%. Depending on the annealing conditions the EPR signals of three supplementary radiation radicals were observed in addition to the main signal caused by CO2¯ radicals. It was found that the presence of these signals in the enamel EPR spectra provides evidence of sample annealing. The possibility of obtaining information about sample history by studying the additional EPR signals is discussed. It can be important to EPR dating and EPR dosimetry. © 2004 Elsevier Ltd. All rights reserved.
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| 6. |
- Yasin, Zafar, et al.
(författare)
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Pion-induced fission - A review
- 2009
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487 .- 1879-0925. ; 44:9-10, s. 846-852
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Konferensbidrag (refereegranskat)abstract
- Real or virtual pions are important ingredients of nuclear reactions at intermediate energies, and their couplings to major nuclear de-excitation modes can determine the final reaction products starting from several beam species. One of these modes is the important fission decay channel for heavy nuclei, induced with real pion beams over a wide range of energies and nuclei, largely using SSNTD. The data have been compared with the predictions of several standard INC reaction models. This review of the data and calculations will provide a status report for this class of reactions. Comparison to fission induced by protons and photons is included to set a context for that induced by real pion beams. (C) 2009 Elsevier Ltd. All rights reserved.
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| 7. |
- af Wåhlberg, Anders E.
(författare)
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Aggregation of driver celeration behavior data : Effects on stability and accident prediction
- 2007
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 45:4, s. 487-500
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Tidskriftsartikel (refereegranskat)abstract
- Predictions about effects of aggregating driver celeration data were tested in a set of data where bus drivers' behavior had been measured repeatedly over three years in a city environment. For drivers with many measurements, this data was correlated with the drivers' accident record at various levels of aggregation over measurements. A single measurement (one sample) was seldom a significant predictor, but for each drive added to a mean, the variation explained in accident record was increased by about 1%. Also, correlations between measurements increased when these were aggregated, and the association with number of passengers (a proxy for traffic density) decreased somewhat, all as predicted. These results show that although driver celeration behavior is only semi-stable across time and environments, aggregating measurements increases both stability and predictive power versus accidents considerably. The celeration variable is therefore promising as a tool for identifying dangerous drivers, if these can be measured repeatedly, or, even better, continuously.
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| 8. |
- af Wåhlberg, Anders E.
(författare)
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If you can’t take the heat : Influences of temperature on bus accident rates
- 2008
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 46:1, s. 66-71
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Tidskriftsartikel (refereegranskat)abstract
- The influences of heat and rain upon accident risk of city buses in a Swedish town were studied for a 10-year time period, but no reliable effects found, despite the fact that the temperature might be as high as 30 degrees C outside the vehicles. As the use of single accidents with buses bypasses many of the methodological problems inherent in the study of weather effects on accident rates, for example changes in general traffic density, the present study was a rather strict test of the hypothesis of increased accident risk due to these factors. It was therefore concluded that rain and high temperatures do not increase the risk of accident for low-speed buses in Sweden. However, there could still be an effect of hot weather on bus accidents at higher temperatures than those normally found in Sweden.
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| 9. |
- Albertsson, Pontus, et al.
(författare)
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Case study: 128 injured in rollover coach crashes in Sweden - injury outcome, mechanisms and possible effects of seat belts.
- 2006
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 44:2, s. 87-109
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Tidskriftsartikel (refereegranskat)abstract
- The risk for injuries in rollover coach crashes are dependent on whether the occupants are belted or not. However, the influence of the different belt systems for reducing injuries has remained unclear. Since many injuries sustained are caused by impacts with the interior, passenger interactions or ejection through a window, the advantages by proper seat belt systems are evident. In this study, representing the most common serious crash scenario for serious injury, 128 injured in rollover cases were analysed with regard to the injury outcome, mechanisms and the possible injury reduction for occupants when using a safety belt. Furthermore, the different belt systems were compared to explain their contribution to increased safety. Based on medical reports and questioning of the passengers, the injuries sustained are recorded according to the AIS classification. The next step was the identification of the injury mechanisms, using the passenger statements as well as results from numerical occupant simulations. It is important to mention that this study was purely focused on detection of the injury mechanism to avoid the reported injuries. The possibility of additional injuries due to the wearing of a belt were not taken into account. However, the analysis of the 128 injured showed a considerable increase in safety for belted occupants through limiting interior contacts, minimising passenger interaction and reducing the possibility of ejection.
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| 10. |
- Arvidsson, Igor, et al.
(författare)
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Adsorption of H, NHx, BHx and BBrx on a (110) surface of c-BN : A quantum-mechanical DFT study
- 2007
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Ingår i: Diamond and related materials. - : Elsevier BV. - 0925-9635 .- 1879-0062. ; 16:1, s. 131-137
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of H, NHx, BHx and BBrx (x = 1, 2 and 3) on hydrogen-terminated (110) surfaces of c-BN has been investigated theoretically. Density Functional Theory (DFT) methods were used in order to study the adsorption processes of these different species on both nitrogen and boron sites at the surfaces. With one exception, all adsorption processes were found to be exothermic and in the order; BBr· BH2· ≈H· > BH· NH· ≈ BBr2· > NH2· BH3· > NH3· > BBr3· for a nitrogen site, and NH2· > NH· > BBr· > H· > BH· > BH2· ≈ BBr2· BBr3· ≈ NH3· ≈BH3· for a boron site. The exception was NH3 being bonded to a surface N site, for which the reaction was slightly endothermic. The various modeling parameters that were used in the calculations of these adsorption energies have been chosen by performing series of extensive test calculations, in which the effect of these parameters (e.g. template size, vacuum depth, atom constraints) on bond-strength have been carefully estimated. Moreover, a semi-empirical method has been evaluated with the purpose to study the usefulness of this type of method for the polar BN compound.
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