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- Adrian-Martinez, S., et al.
(författare)
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A first search for coincident gravitational waves and high energy neutrinos using LIGO, Virgo and ANTARES data from 2007
- 2013
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :6
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
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| 5. |
- Thorn, D. B., et al.
(författare)
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Polarization and anisotropic emission of K-shell radiation from heavy few electron ions
- 2011
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Ingår i: Canadian journal of physics (Print). - 0008-4204 .- 1208-6045. ; 89:5, s. 513-519
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Tidskriftsartikel (refereegranskat)abstract
- The population of magnetic sublevels in hydrogen-like uranium ions has been investigated in relativistic ion-atom collisions by observing the subsequent X-ray emission. Using the gas target at the experimental storage ring facility we observed the angular emission of Lyman-alpha radiation from hydrogen-like uranium ions. The alignment parameter for three different interaction energies was measured and found to agree well with theory. In addition, the use of different gas targets allowed for the electron-impact excitation process to be observed.
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| 9. |
- Guddat, S., et al.
(författare)
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Synthesis, characterization, and detection of new oxandrolone metabolites as long-term markers in sports drug testing
- 2013
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 405:25, s. 8285-8294
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Tidskriftsartikel (refereegranskat)abstract
- The discovery and implementation of the long-term metabolite of metandienone, namely 17 beta-hydroxymethyl-17 alpha-methyl-18-norandrost-1,4,13-trien-3-one, to doping control resulted in hundreds of positive metandienone findings worldwide and impressively demonstrated that prolonged detection periods significantly increase the effectiveness of sports drug testing. For oxandrolone and other 17-methyl steroids, analogs of this metabolite have already been described, but comprehensive characterization and pharmacokinetic data are still missing. In this report, the synthesis of the two epimeric oxandrolone metabolites-17 beta-hydroxymethyl-17 alpha-methyl-18-nor-2-oxa-5 alpha-androsta-13-en-3-one and 17 alpha-hydroxymethyl-17 beta-methyl-18-nor-2-oxa-5 alpha-androsta-13-en-3-one-using a fungus (Cunninghamella elegans) based protocol is presented. The reference material was fully characterized by liquid chromatography nuclear magnetic resonance spectroscopy and high resolution/high accuracy mass spectrometry. To ensure a specific and sensitive detection in athlete's urine, different analytical approaches were followed, such as liquid chromatography-tandem mass spectrometry (QqQ and Q-Orbitrap) and gas chromatography-tandem mass spectrometry, in order to detect and identify the new target analytes. The applied methods have demonstrated good specificity and no significant matrix interferences. Linearity (R (2) > 0.99) was tested, and precise results were obtained for the detection of the analytes (coefficient of variation < 20 %). Limits of detection (S/N) for confirmatory and screening analysis were estimated at 1 and 2 ng/mL of urine, respectively. The assay was applied to oxandrolone post-administration samples to obtain data on the excretion of the different oxandrolone metabolites. The studied specimens demonstrated significantly longer detection periods (up to 18 days) for the new oxandrolone metabolites compared to commonly targeted metabolites such as epioxandrolone or 18-nor-oxandrolone, presenting a promising approach to improve the fight against doping.
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| 11. |
- Mohaupt, P., et al.
(författare)
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Extension and optimization of the load range of DRT test systems for testing extra long HV and UHV cables
- 2012
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Ingår i: 44th International Conference on Large High Voltage Electric Systems 2012.
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Konferensbidrag (refereegranskat)abstract
- In the last few years, the demand for testing extra-long cables, such as submarine cables has grown rapidly. The existing testing methods have been complemented by a new testing technology called DRT (Differential Resonance Technology). This testing method enables testing of extra-long cables by comparably small and light-weight equipment using a low frequency for the test voltage, e.g. 0.1Hz up to 5Hz. This leads to a significant decrease of the required power of the test source [1]. In a resonant circuit only the losses of the generator's individual components, specifically the high voltage reactor, have to be covered by the mains. The testing power itself remains fully compensated. Typical ratios between the testing power and the input power of resonant test systems start at 50 and go up to 100, depending on the load. Unfortunately, voltage generation based on inductive generation principles such as resonant circuits cannot economically be used for frequencies below 10Hz due to the massive iron cores needed for such a low frequency. The DRT method for the generation of low frequency high voltage is based on a high frequency voltage whose amplitude is modulated by the desired low frequency. Using a resonator, which is tuned to the high frequency, and a demodulator, the desired low frequency high voltage can be generated [1,2]. The input power required - and in direct relation to this the size and weight of the equipment - is significantly smaller than for other existing methods. In order to optimize the operation performance of the DRT system, this paper describes mathematical methods and algorithms, which have already been implemented and tested in a DRT test set. The basis for these algorithms is a mathematical description of the system based on an envelope model. Using this mathematical description of the nonlinear system behavior, a systematic analysis of the performance and the limits of the system can be given. The theoretical approach was experimentally proven by measuring the output voltage and the input power of a prototype unit ultimately designed to produce 200 kV rms. A first test was performed at SP Technical Research Institute of Sweden, using their reference measurement system for very low frequency (VLF) [3, 4] to measure the high VLF voltage. The reference measurement system provides a traceable uncertainty of down to 0.04 % over a voltage range up to 200 kV rms. The frequency range of the reference system is from 0.1 Hz up to 50 Hz. This system permits acquisition of complete waveforms that can be analysed for harmonic content and/or THD (Total Harmonic Distortion). Further tests are planned, where the connected load will be increased to the specified maximum 1 μF at 200 kV, and the characteristics will be explored both as regards to output voltage quality, input power requirements and distortion on the input current.
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| 12. |
- Mohaupt, P., et al.
(författare)
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Extension and optimization of the load range of DRT test systems for testing extra-long HV and UHV cables
- 2013
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Ingår i: Elektrotechnik und Informationstechnik. - : Springer Science and Business Media LLC. - 0932-383X.
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Tidskriftsartikel (refereegranskat)abstract
- In the last few years, the demand for testing extra-long cables, such as submarine cables has grown rapidly. The existing testing methods have been complemented by a new testing technology called DRT (Differential Resonance Technology). This testing method enables testing of extra-long cables by comparably small and light-weight equipment using a low frequency for the test voltage, e.g. 0.1 Hz up to 5 Hz. This leads to a significant decrease of the required power of the test source (P. Mohaupt and A. Bergman in CIGRE 2010). In a resonant circuit only the losses of the generator's individual components, specifically the high voltage reactor, have to be covered by the mains. The testing power itself remains fully compensated. Typical ratios between the testing power and the input power of resonant test systems start at 50 and go up to 100, depending on the load. Unfortunately, voltage generation based on inductive generation principles such as resonant circuits cannot economically be used for frequencies below 10 Hz due to the massive iron cores needed for such a low frequency. The DRT method for the generation of low frequency high voltage is based on a high frequency voltage whose amplitude is modulated by the desired low frequency. Using a resonator, which is tuned to the high frequency, and a demodulator, the desired low frequency high voltage can be generated (P. Mohaupt and A. Bergman in CIGRE 2010; P. Mohaupt and T. Mehl in Jicable 2011). The input power required-and in direct relation to this the size and weight of the equipment-is significantly smaller than for other existing methods. In order to optimize the operation performance of the DRT system, this paper describes mathematical methods and algorithms, which have already been implemented and tested in a DRT test set. The basis for these algorithms is a mathematical description of the system based on an envelope model. Using this mathematical description of the nonlinear system behavior, a systematic analysis of the performance and the limits of the system can be given. The theoretical approach was experimentally proven by measuring the output voltage and the input power of a prototype unit ultimately designed to produce 200 kV rms. A first test was performed at SP Technical Research Institute of Sweden, using their reference measurement system for very low frequency (VLF) S. Bergman and A. Bergman (Proc. CPEM Conf. Dig., pp. 682-683, 2010; IEEE Trans. Instrum. Meas. 60:2422-2426, 2011) to measure the high VLF voltage. The reference measurement system provides a traceable uncertainty of down to 0.04 % over a voltage range up to 200 kV rms. The frequency range of the reference system is from 0.1 Hz up to 50 Hz. This system permits acquisition of complete wave-forms that can be analysed for harmonic content and/or THD (Total Harmonic Distortion). Further tests are planned, where the connected load will be increased to the specified maximum 1 μF at 200 kV, and the characteristics will be explored both as regards to output voltage quality, input power requirements and distortion on the input current. © 2013 CIGRE -- Reprint from www.cigre.org with kind permission.
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