| 1. |
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| 2. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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| 3. |
- Achten, Peter, et al.
(författare)
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MEASURING THE LOSSES OF HYDROSTATIC PUMPS AND MOTORS: A CRITICAL REVIEW OF ISO4409:2007
- 2020
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Ingår i: PROCEEDINGS OF THE ASME/BATH SYMPOSIUM ON FLUID POWER AND MOTION CONTROL, 2019. - : AMER SOC MECHANICAL ENGINEERS. - 9780791859339
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Konferensbidrag (refereegranskat)abstract
- ISO 4409 is the most important international standard for measuring the efficiency of hydraulic pumps and motors, the latest edition being 4409:2007. The standard describes methods for determining the steady-state performance in terms of overall efficiency. It also defines equations for calculating the volumetric efficiency of pumps and motors. The hydromechanical efficiency is only defined for motors, not for pumps. This paper analyses the efficiency and losses of pumps and motors in an alternative way. The preference is on loss analysis instead of efficiencies. Especially the effects of the bulk modulus are considered in a different and more inclusive manner. The new methodology results in a higher total loss for motor and a lower total loss for pumps than the current ISO 4409 standard. Furthermore, it results in significant changes of the hydro-mechanical and volumetric losses. The differences between the new methodology and ISO 4409 become larger for high load pressures. The new methodology demands knowledge about the minimum volume of the displacement chamber. The ratio between this volume and the full displacement of a single displacement chamber strongly influences the hydro mechanical and volumetric losses of the pump or motor. The new methodology is valid for all positive displacement hydrostatic pumps and motors. The volumetric efficiency, as defined in ISO 4409, can still be used as a flow rate factor, but should not be regarded as an energy conversion efficiency. The importance of adopting the proposed methodology is further demonstrated by analyzing and comparing the measurement data about a fixed displacement pump and motor, showing the differences in the loss analysis by means of ISO 4409 and the new equations. The methodology, observations and validation results presented in this paper are significant and can pave the road for improving the current ISO 4409:2007 standard, which would ultimately benefit the industry.
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| 4. |
- Blauenfeldt, Rolf Ankerlund, et al.
(författare)
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Remote Ischemic Conditioning for Acute Stroke : The RESIST Randomized Clinical Trial
- 2023
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Ingår i: JAMA. - 0098-7484. ; 330:13, s. 1236-1246
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Despite some promising preclinical and clinical data, it remains uncertain whether remote ischemic conditioning (RIC) with transient cycles of limb ischemia and reperfusion is an effective treatment for acute stroke. Objective: To evaluate the effect of RIC when initiated in the prehospital setting and continued in the hospital on functional outcome in patients with acute stroke. Design, Setting, and Participants: This was a randomized clinical trial conducted at 4 stroke centers in Denmark that included 1500 patients with prehospital stroke symptoms for less than 4 hours (enrolled March 16, 2018, to November 11, 2022; final follow-up, February 3, 2023). Intervention: The intervention was delivered using an inflatable cuff on 1 upper extremity (RIC cuff pressure, ≤200 mm Hg [n = 749] and sham cuff pressure, 20 mm Hg [n = 751]). Each treatment application consisted of 5 cycles of 5 minutes of cuff inflation followed by 5 minutes of cuff deflation. Treatment was started in the ambulance and repeated at least once in the hospital and then twice daily for 7 days among a subset of participants. Main Outcomes and Measures: The primary end point was improvement in functional outcome measured as a shift across the modified Rankin Scale (mRS) score (range, 0 [no symptoms] to 6 [death]) at 90 days in the target population with a final diagnosis of ischemic or hemorrhagic stroke. Results: Among 1500 patients who were randomized (median age, 71 years; 591 women [41%]), 1433 (96%) completed the trial. Of these, 149 patients (10%) were diagnosed with transient ischemic attack and 382 (27%) with a stroke mimic. In the remaining 902 patients with a target diagnosis of stroke (737 [82%] with ischemic stroke and 165 [18%] with intracerebral hemorrhage), 436 underwent RIC and 466 sham treatment. The median mRS score at 90 days was 2 (IQR, 1-3) in the RIC group and 1 (IQR, 1-3) in the sham group. RIC treatment was not significantly associated with improved functional outcome at 90 days (odds ratio [OR], 0.95; 95% CI, 0.75 to 1.20, P =.67; absolute difference in median mRS score, -1; -1.7 to -0.25). In all randomized patients, there were no significant differences in the number of serious adverse events: 169 patients (23.7%) in the RIC group with 1 or more serious adverse events vs 175 patients (24.3%) in the sham group (OR, 0.97; 95% CI, 0.85 to 1.11; P =.68). Upper extremity pain during treatment and/or skin petechia occurred in 54 (7.2%) in the RIC group and 11 (1.5%) in the sham group. Conclusions and Relevance: RIC initiated in the prehospital setting and continued in the hospital did not significantly improve functional outcome at 90 days in patients with acute stroke. Trial Registration: ClinicalTrials.gov Identifier: NCT03481777.
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| 5. |
- Brütt, Katharina, et al.
(författare)
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Competition and moral behavior: A meta-analysis of forty-five crowd-sourced experimental designs
- 2023
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Ingår i: Proceedings of the National Academy of Sciences - PNAS. - : National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 120:23
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Tidskriftsartikel (refereegranskat)abstract
- Does competition affect moral behavior? This fundamental question has been debated among leading scholars for centuries, and more recently, it has been tested in experimental studies yielding a body of rather inconclusive empirical evidence. A potential source of ambivalent empirical results on the same hypothesis is design heterogeneity-variation in true effect sizes across various reasonable experimental research protocols. To provide further evidence on whether competition affects moral behavior and to examine whether the generalizability of a single experimental study is jeopardized by design heterogeneity, we invited independent research teams to contribute experimental designs to a crowd-sourced project. In a large-scale online data collection, 18,123 experimental participants were randomly allocated to 45 randomly selected experimental designs out of 95 submitted designs. We find a small adverse effect of competition on moral behavior in a meta-analysis of the pooled data. The crowd-sourced design of our study allows for a clean identification and estimation of the variation in effect sizes above and beyond what could be expected due to sampling variance. We find substantial design heterogeneity-estimated to be about 1.6 times as large as the average standard error of effect size estimates of the 45 research designs-indicating that the informativeness and generalizability of results based on a single experimental design are limited. Drawing strong conclusions about the underlying hypotheses in the presence of substantive design heterogeneity requires moving toward much larger data collections on various experimental designs testing the same hypothesis.
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| 6. |
- Coustenis, A., et al.
(författare)
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TandEM : Titan and Enceladus mission
- 2009
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:3, s. 893-946
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Tidskriftsartikel (refereegranskat)abstract
- TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (MontgolfiSre) and possibly several landing probes to be delivered through the atmosphere.
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| 7. |
- Elsayed, Hesham, et al.
(författare)
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VRSketchPen : unconstrained haptic assistance for sketching in virtual 3D environments
- 2020
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Ingår i: Proceedings of the 26th ACM Symposium on Virtual Reality Software and Technology. - New York, NY, United States : Association for Computing Machinery (ACM). ; , s. 1-11
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Konferensbidrag (refereegranskat)abstract
- Accurate sketching in virtual 3D environments is challenging due to aspects like limited depth perception or the absence of physical support. To address this issue, we propose VRSketchPen – a pen that uses two haptic modalities to support virtual sketching without constraining user actions: (1) pneumatic force feedback to simulate the contact pressure of the pen against virtual surfaces and (2) vibrotactile feedback to mimic textures while moving the pen over virtual surfaces. To evaluate VRSketchPen, we conducted a lab experiment with 20 participants to compare (1) pneumatic, (2) vibrotactile and (3) a combination of both with (4) snapping and no assistance for flat and curved surfaces in a 3D virtual environment. Our findings show that usage of pneumatic, vibrotactile and their combination significantly improves 2D shape accuracy and leads to diminished depth errors for flat and curved surfaces. Qualitative results indicate that users find the addition of unconstraining haptic feedback to significantly improve convenience, confidence and user experience.
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| 8. |
- Frykholm, Peter, 1961-, et al.
(författare)
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Pre-operative fasting in children : A guideline from the European Society of Anaesthesiology and Intensive Care
- 2022
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Ingår i: European Journal of Anaesthesiology. - : European Society of Anaesthesiology and Intensive Care. - 0265-0215 .- 1365-2346. ; 39:1, s. 4-25
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Tidskriftsartikel (refereegranskat)abstract
- Current paediatric anaesthetic fasting guidelines have recommended conservative fasting regimes for many years and have not altered much in the last decades. Recent publications have employed more liberal fasting regimes with no evidence of increased aspiration or regurgitation rates. In this first solely paediatric European Society of Anaesthesiology and Intensive Care (ESAIC) pre-operative fasting guideline, we aim to present aggregated and evidence-based summary recommendations to assist clinicians, healthcare providers, patients and parents.We identified six main topics for the literature search: studies comparing liberal with conservative regimens; impact of food composition; impact of comorbidity; the use of gastric ultrasound as a clinical tool; validation of gastric ultrasound for gastric content and gastric emptying studies; and early postoperative feeding. The literature search was performed by a professional librarian in collaboration with the ESAIC task force.Recommendations for reducing clear fluid fasting to 1 h, reducing breast milk fasting to 3 h, and allowing early postoperative feeding were the main results, with GRADE 1C or 1B evidence. The available evidence suggests that gastric ultrasound may be useful for clinical decision-making, and that allowing a ‘light breakfast’ may be well tolerated if the intake is well controlled. More research is needed in these areas as well as evaluation of how specific patient or treatment-related factors influence gastric emptying.
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| 9. |
- Goderis, Steven, et al.
(författare)
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Globally distributed iridium layer preserved within the Chicxulub impact structure
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:9
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Tidskriftsartikel (refereegranskat)abstract
- The Cretaceous-Paleogene (K-Pg) mass extinction is marked globally by elevated concentrations of iridium, emplaced by a hypervelocity impact event 66 million years ago. Here, we report new data from four independent laboratories that reveal a positive iridium anomaly within the peak-ring sequence of the Chicxulub impact structure, in drill core recovered by IODP-ICDP Expedition 364. The highest concentration of ultrafine meteoritic matter occurs in the post-impact sediments that cover the crater peak ring, just below the lowermost Danian pelagic limestone. Within years to decades after the impact event, this part of the Chicxulub impact basin returned to a relatively low-energy depositional environment, recording in unprecedented detail the recovery of life during the succeeding millennia. The iridium layer provides a key temporal horizon precisely linking Chicxulub to K-Pg boundary sections worldwide.
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| 10. |
- Gogolev, Ivan, 1984, et al.
(författare)
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Chemical-looping combustion in a 100 kW unit using a mixture of synthetic and natural oxygen carriers - Operational results and fate of biomass fuel alkali
- 2019
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 88, s. 371-382
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Tidskriftsartikel (refereegranskat)abstract
- Biomass fuel use in chemical looping combustion enables negative CO2 emissions through BECCS (Bio-Energy Carbon Capture and Storage). Effective biomass utilization in CLC requires an economical and effective oxygen carrier to achieve high fuel conversion, effective CO2 capture, and management of the harmful effects of biomass alkali release (bed agglomeration, oxygen carrier deactivation, fouling and corrosion). These issues were addressed in 100 kW CLC pilot experiments. Building on previous work, a mixture of a synthetic calcium manganite perovskite and natural ilmenite was used as the oxygen carrier. Four biomass fuels of varied alkali content were tested: black pellets of steam-exploded stem wood (BP), BP impregnated with K2CO3, a mixture of 50% BP with 50% straw pellets, and wood char. Experiments showed high fuel conversion and very high CO2 capture, with overall performance exceeding that of ilmenite and manganese ore. More than 95% gas conversion was achieved with black pellets at around 950 degrees C. The fate of biomass alkali, previously virtually unknown in CLC research, was explored by implementing online surface-ionization-based measurement of alkali released in the flue gases of the fuel reactor (FR) and air reactor (AR). Release levels were found to correlate with the fuel alkali content. The flue gas measurements and bed material elemental analyses suggest that most of the fuel alkali are accumulated in the oxygen carrier. Unexpectedly, it was found that flue gas alkali release occurs in both the FR and AR, with AR exhibiting an equal or higher rate of release vs. the FR.
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