| 1. |
- Abdalla, H., et al.
(författare)
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Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation
- 2021
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : Institute of Physics Publishing (IOPP). - 1475-7516. ; :2
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Tidskriftsartikel (refereegranskat)abstract
- The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for gamma-ray astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of the salient areas of gamma-ray cosmology that can be explored as part of the Key Science Projects of CTA, through simulated observations of active galactic nuclei (AGN) and of their relativistic jets. Observations of AGN with CTA will enable a measurement of gamma-ray absorption on the extragalactic background light with a statistical uncertainty below 15% up to a redshift z = 2 and to constrain or detect gamma-ray halos up to intergalactic-magnetic-field strengths of at least 0.3 pG. Extragalactic observations with CTA also show promising potential to probe physics beyond the Standard Model. The best limits on Lorentz invariance violation from gamma-ray astronomy will be improved by a factor of at least two to three. CTA will also probe the parameter space in which axion-like particles could constitute a significant fraction, if not all, of dark matter. We conclude on the synergies between CTA and other upcoming facilities that will foster the growth of gamma-ray cosmology.
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| 2. |
- Al Kharusi, S., et al.
(författare)
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SNEWS 2.0 : a next-generation supernova early warning system for multi-messenger astronomy
- 2021
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 23:3
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Forskningsöversikt (refereegranskat)abstract
- The next core-collapse supernova in the Milky Way or its satellites will represent a once-in-a-generation opportunity to obtain detailed information about the explosion of a star and provide significant scientific insight for a variety of fields because of the extreme conditions found within. Supernovae in our galaxy are not only rare on a human timescale but also happen at unscheduled times, so it is crucial to be ready and use all available instruments to capture all possible information from the event. The first indication of a potential stellar explosion will be the arrival of a bright burst of neutrinos. Its observation by multiple detectors worldwide can provide an early warning for the subsequent electromagnetic fireworks, as well as signal to other detectors with significant backgrounds so they can store their recent data. The supernova early warning system (SNEWS) has been operating as a simple coincidence between neutrino experiments in automated mode since 2005. In the current era of multi-messenger astronomy there are new opportunities for SNEWS to optimize sensitivity to science from the next galactic supernova beyond the simple early alert. This document is the product of a workshop in June 2019 towards design of SNEWS 2.0, an upgraded SNEWS with enhanced capabilities exploiting the unique advantages of prompt neutrino detection to maximize the science gained from such a valuable event.
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| 3. |
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| 4. |
- Kjellberg, A, et al.
(författare)
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Hyperbaric oxygen for treatment of long COVID-19 syndrome (HOT-LoCO): protocol for a randomised, placebo-controlled, double-blind, phase II clinical trial
- 2022
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 12:11, s. e061870-
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Tidskriftsartikel (refereegranskat)abstract
- Long COVID-19, where symptoms persist 12 weeks after the initial SARS-CoV-2-infection, is a substantial problem for individuals and society in the surge of the pandemic. Common symptoms are fatigue, postexertional malaise and cognitive dysfunction. There is currently no effective treatment and the underlying mechanisms are unknown, although several hypotheses exist, with chronic inflammation as a common denominator. In prospective studies, hyperbaric oxygen therapy (HBOT) has been suggested to be effective for the treatment of similar syndromes such as chronic fatigue syndrome and fibromyalgia. A case series has suggested positive effects of HBOT in long COVID-19. This randomised, placebo-controlled clinical trial will explore HBOT as a potential treatment for long COVID-19. The primary objective is to evaluate if HBOT improves health-related quality of life (HRQoL) for patients with long COVID-19 compared with placebo/sham. The main secondary objective is to evaluate whether HBOT improves endothelial function, objective physical performance and short-term HRQoL.Methods and analysisA randomised, placebo-controlled, double-blind, phase II clinical trial in 80 previously healthy subjects debilitated due to long COVID-19, with low HRQoL. Clinical data, HRQoL questionnaires, blood samples, objective tests and activity metre data will be collected at baseline. Subjects will be randomised to a maximum of 10 treatments with hyperbaric oxygen or sham treatment over 6 weeks. Assessments for safety and efficacy will be performed at 6, 13, 26 and 52 weeks, with the primary endpoint (physical domains in RAND 36-Item Health Survey) and main secondary endpoints defined at 13 weeks after baseline. Data will be reviewed by an independent data safety monitoring board.Ethics and disseminationThe trial is approved by the Swedish National Institutional Review Board (2021–02634) and the Swedish Medical Products Agency (5.1-2020-36673). Positive, negative and inconclusive results will be published in peer-reviewed scientific journals with open access.Trial registration numberNCT04842448.
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| 7. |
- Etman, Ahmed S., 1986-, et al.
(författare)
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Mo1.33CTz-Ti3C2Tz mixed MXene freestanding films for zinc-ion hybrid supercapacitors
- 2021
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Ingår i: Materials Today Energy. - : Elsevier. - 2468-6069. ; 22
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Tidskriftsartikel (refereegranskat)abstract
- The high demand on fast rechargeable batteries and supercapacitors combined with the limited resources of their active materials (e.g. Li and Co) motivate the exploration of sustainable energy storage systems such as Zn-ion hybrid supercapacitors. MXenes are two-dimensional materials with outstanding properties such as high conductivity and capacitance which enhance their performance in energy storage devices. Herein, we report on the use of freestanding Mo1.33CTz–Ti3C2Tz mixed MXene films in Zn-ion hybrid supercapacitors. The mixed MXene films are prepared from pristine MXene suspensions using a one-step vacuum filtration approach. The mixed MXene delivers capacities of about 159 and 59 mAh/g at scan rates of 0.5 and 100 mV/s, respectively. These capacity values are higher than the pristine MXene films and previously reported values for MXene electrodes in Zn-ion supercapacitors. Furthermore, the electrodes offer a promising capacity retention of about 90% after 8,000 cycles. In addition, the mixed MXene features energy densities of about 103 and 38 Wh/kg at power densities of 0.143 and 10.6 kW/kg, respectively. Insights into the effect of electrode thickness on rate performance and the mechanism of charge storage are also discussed. This study opens a venue for the use of Mo1.33CTz–Ti3C2Tz mixed MXene electrodes in sustainable energy storage systems with high energy density and power density.
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| 8. |
- Gyamfi, S., et al.
(författare)
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Calibration of LKAB's Konsuln test mine ventilation model using barometer Pressure-Quantity (PQ) survey
- 2021
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Ingår i: Mine Ventilation. - London : Taylor & Francis. ; , s. 23-33
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Konferensbidrag (refereegranskat)abstract
- Ventilation projects such as installation of primary fans, refrigeration system, heating systems, and Ventilation of Demand (VOD) system require some simulations to ascertain their benefits and fulfilment of their purpose before the actual financial commitment is made to execute such projects. Ventilation models used for the simulations should provide some degree of accuracy to ensure that their results will reflect the actual mine ventilation circuit. This paper outlines a barometer Pressure-Quantity (PQ) survey that was done to calibrate the existing ventilation model of LKAB’s Konsuln test mine before it was used in a VOD design study to determine whether it will be feasible for Konsuln mine to install the system. The results show a good correlation between the simulated airflows in the calibrated model and the actual underground measured airflow quantities and primary fans pressure. This good correlation has validated the model for its use in Konsuln VOD design study.
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| 9. |
- Gyamfi, S., et al.
(författare)
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Development of Strategies to Reduce Ventilation and Heating Costs in a Swedish Sublevel Caving Mine—a Unique Case of LKAB’s Konsuln Mine
- 2022
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Ingår i: Mining, Metallurgy & Exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 39:2, s. 221-238
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Tidskriftsartikel (refereegranskat)abstract
- This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine 2018–2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 3 Mtpa in the future, and this requires the primary fans to be upgraded. Therefore, a study was carried out to determine whether using ventilation on demand (VOD) could avoid this fan upgrade and reduce Konsuln’s ventilation and heating power costs in the future. The study also investigated whether using battery electric vehicles (BEVs) along with VOD or as a standalone strategy could further reduce these power costs. In addition, the study analyzed the suitability of heating power reduction strategies presently or previously used in the Nordic countries and Canada to investigate potential additional strategies to reduce the heating power cost, the largest portion of Konsuln’s ventilation and heating power costs. The study found using VOD can avoid the expensive upgrading of the existing primary fans and reduce Konsuln’s ventilation and heating power costs in the future. Using BEVs can further reduce these costs. Finally, none of the Nordic and Canadian heating power reduction strategies is suitable for Konsuln because they require unique conditions that do not exist in Konsuln.
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| 10. |
- Halim, Adrianus, et al.
(författare)
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An overview of the Nordic mine ventilation system
- 2020
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Ingår i: CIM Journal. - London : Taylor & Francis. - 1923-6026 .- 2689-8403. ; 11:2, s. 111-119
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the ventilation system used in underground hard rock mines in Sweden and Finland, which differs in many respects from the system commonly used in other major mining countries such as Australia, Canada, South Africa, and the USA. The Nordic system utilizes auxiliary fans with a variable speed drive to distribute primary airflow to working levels instead of regulators, which are commonly used in other countries. In addition to comparing the Nordic system with the system used in other countries, this paper describes the system’s ventilation-on-demand and air conditioning, as well as ventilation regulations in Sweden and Finland. A discussion regarding the potential to use natural-assisted refrigeration in the future is also described in this paper.
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