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- Zohm, H., et al.
(författare)
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Overview of ASDEX upgrade results in view of ITER and DEMO
- 2024
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Ingår i: Nuclear Fusion. - 0029-5515 .- 1741-4326. ; 64:11
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Tidskriftsartikel (refereegranskat)abstract
- Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER and EU DEMO. A major objective of the AUG programme is to shed light on the underlying physics of confinement, stability, and plasma exhaust in order to allow reliable extrapolation of results obtained on present day machines to these reactor-grade devices. Concerning pedestal physics, the mitigation of edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found to be consistent with a reduction of the linear peeling-ballooning stability threshold due to the helical deformation of the plasma. Conversely, ELM suppression by RMPs is ascribed to an increased pedestal transport that keeps the plasma away from this boundary. Candidates for this increased transport are locally enhanced turbulence and a locked magnetic island in the pedestal. The enhanced D-alpha (EDA) and quasi-continuous exhaust (QCE) regimes have been established as promising ELM-free scenarios. Here, the pressure gradient at the foot of the H-mode pedestal is reduced by a quasi-coherent mode, consistent with violation of the high-n ballooning mode stability limit there. This is suggestive that the EDA and QCE regimes have a common underlying physics origin. In the area of transport physics, full radius models for both L- and H-modes have been developed. These models predict energy confinement in AUG better than the commonly used global scaling laws, representing a large step towards the goal of predictive capability. A new momentum transport analysis framework has been developed that provides access to the intrinsic torque in the plasma core. In the field of exhaust, the X-Point Radiator (XPR), a cold and dense plasma region on closed flux surfaces close to the X-point, was described by an analytical model that provides an understanding of its formation as well as its stability, i.e., the conditions under which it transitions into a deleterious MARFE with the potential to result in a disruptive termination. With the XPR close to the divertor target, a new detached divertor concept, the compact radiative divertor, was developed. Here, the exhaust power is radiated before reaching the target, allowing close proximity of the X-point to the target. No limitations by the shallow field line angle due to the large flux expansion were observed, and sufficient compression of neutral density was demonstrated. With respect to the pumping of non-recycling impurities, the divertor enrichment was found to mainly depend on the ionisation energy of the impurity under consideration. In the area of MHD physics, analysis of the hot plasma core motion in sawtooth crashes showed good agreement with nonlinear 2-fluid simulations. This indicates that the fast reconnection observed in these events is adequately described including the pressure gradient and the electron inertia in the parallel Ohm’s law. Concerning disruption physics, a shattered pellet injection system was installed in collaboration with the ITER International Organisation. Thanks to the ability to vary the shard size distribution independently of the injection velocity, as well as its impurity admixture, it was possible to tailor the current quench rate, which is an important requirement for future large devices such as ITER. Progress was also made modelling the force reduction of VDEs induced by massive gas injection on AUG. The H-mode density limit was characterised in terms of safe operational space with a newly developed active feedback control method that allowed the stability boundary to be probed several times within a single discharge without inducing a disruptive termination. Regarding integrated operation scenarios, the role of density peaking in the confinement of the ITER baseline scenario (high plasma current) was clarified. The usual energy confinement scaling ITER98(p,y) does not capture this effect, but the more recent H20 scaling does, highlighting again the importance of developing adequate physics based models. Advanced tokamak scenarios, aiming at large non-inductive current fraction due to non-standard profiles of the safety factor in combination with high normalised plasma pressure were studied with a focus on their access conditions. A method to guide the approach of the targeted safety factor profiles was developed, and the conditions for achieving good confinement were clarified. Based on this, two types of advanced scenarios (‘hybrid’ and ‘elevated’ q-profile) were established on AUG and characterised concerning their plasma performance.
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| 2. |
- Ngasala, Billy E., et al.
(författare)
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Efficacy and safety of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in mainland Tanzania, 2019
- 2024
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Ingår i: MALARIA JOURNAL. - 1475-2875. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Artemisinin-based combination therapy (ACT) has been a major contributor to the substantial reductions in global malaria morbidity and mortality over the last decade. In Tanzania, artemether-lumefantrine (AL) was introduced as the first-line treatment for uncomplicated Plasmodium falciparum malaria in 2006. The World Health Organization (WHO) recommends regular assessment and monitoring of the efficacy of the first-line treatment, specifically considering that artemisinin resistance has been confirmed in the Greater Mekong sub-region. This study's main aim was to assess the efficacy and safety of AL for treating uncomplicated P. falciparum malaria in Tanzania.Methods This was a single-arm prospective antimalarial drug efficacy trial conducted in four of the eight National Malaria Control Programme (NMCP) sentinel sites in 2019. The trial was carried out in outpatient health facilities in Karume-Mwanza region, Ipinda-Mbeya region, Simbo-Tabora region, and Nagaga-Mtwara region. Children aged six months to 10 years with microscopy confirmed uncomplicated P. falciparum malaria who met the inclusion criteria were recruited based on the WHO protocol. The children received AL (a 6-dose regimen of AL twice daily for three days). Clinical and parasitological parameters were monitored during follow-up over 28 days to evaluate drug efficacy.Results A total of 628 children were screened for uncomplicated malaria, and 349 (55.6%) were enrolled between May and September 2019. Of the enrolled children, 343 (98.3%) completed the 28-day follow-up or attained the treatment outcomes. There were no early treatment failures; recurrent infections during follow-up were common at two sites (Karume 29.5%; Simbo 18.2%). PCR-corrected adequate clinical and parasitological response (ACPR) by survival analysis to AL on day 28 of follow-up varied from 97.7% at Karume to 100% at Ipinda and Nagaga sites. The commonly reported adverse events were cough, skin pallor, and abdominal pain. The drug was well tolerated, and no serious adverse event was reported.Conclusion This study showed that AL had adequate efficacy and safety for the treatment of uncomplicated falciparum malaria in Tanzania in 2019. The high recurrent infections were mainly due to new infections, highlighting the potential role of introducing alternative artemisinin-based combinations that offer improved post-treatment prophylaxis, such as artesunate-amodiaquine (ASAQ).
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| 3. |
- Rashid, Farhan Lafta, et al.
(författare)
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A review of the current situation and prospects for nanofluids to improve solar still performance
- 2024
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Ingår i: Journal of thermal analysis and calorimetry (Print). - : Springer. - 1388-6150 .- 1588-2926.
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Tidskriftsartikel (refereegranskat)abstract
- Drinking water production has been thrust to the forefront of global issues as a direct result of the critical need for accessto clean water and the expanding environmental difculties. Solar stills are becoming an increasingly popular technologyfor the purifcation of water since they provide a greener and more cost-efective alternative to the production of distilledwater of a high standard. Recent research has focused on the incorporation of nanofuids, which are suspensions of metallicor non-metallic nanoparticles, into base fuids such as water and oil in the hopes of further increasing the efectiveness ofsolar distillation. This novel technique intends to improve thermophysical and evaporation parameters, which will eventuallylead to greater production in solar stills. In this paper, a complete overview of the most recent developments in the use ofnanofuids in solar still technology is presented. This research investigates the potential of nanofuid-flled solar still systemsby focusing on their one-of-a-kind qualities. These qualities include increased thermophysical properties, better thermalconductivity, and enhanced thermal absorptivity. The innovative nature of this method is highlighted by the fact that the use of nanofuids in active solar stills has proven a decrease in the amount of pumping power that is required. For instance, ithas been ascertained that the inclusion of carbon quantum dots nanofuids to a solar still can expressively improve the waterproduction, boosting the output by 57.9% to 823 mL compared to the 521 mL produced by a conventional still. Also, usinga concentration of 0.9%, Al2O3, TiO2, CuO nanofuids and multiwall carbon nanotubes can boost the water production by11.57%, 7.16%, 6.32%, and 4.66%, respectively, if compared to a solar still without nanofuids. This study serves as a pioneering examination of the future possibilities of nanofuid-enabled solar still systems, shining light on a transformational routetoward environmentally friendly and efective water purifcation technologies. In light of these astonishing discoveries, thisresearch serves as a pioneering exploration of the future prospects of nanofuid-enabled solar desalination units.
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