| 1. |
|
|
| 2. |
- Agredano Torres, Manuel, et al.
(författare)
-
Coils and power supplies design for the SMART tokamak
- 2021
-
Ingår i: Fusion engineering and design. - : Elsevier BV. - 0920-3796 .- 1873-7196. ; 168, s. 112683-112683
-
Tidskriftsartikel (refereegranskat)abstract
- A new spherical tokamak, the SMall Aspect Ratio Tokamak (SMART), is currently being designed at the University of Seville. The goal of the machine is to achieve a toroidal field of 1 T, a plasma current of 500 kA and a pulse length of 500 ms for a plasma with a major radius of 0.4 m and minor radius of 0.25 m. This contribution presents the design of the coils and power supplies of the machine. The design foresees a central solenoid, 12 toroidal field coils and 8 poloidal field coils. Taking the current waveforms for these set of coils as starting point, each of them has been designed to withstand the Joule heating during the tokamak operation time. An analytical thermal model is employed to obtain the cross sections of each coil and, finally, their dimensions and parameters. The design of flexible and modular power supplies, based on IGBTs and supercapacitors, is presented. The topologies and control strategy of the power supplies are explained, together with a model in MATLAB Simulink to simulate the power supplies performance, proving their feasibility before the construction of the system.
|
|
| 3. |
- Dominoni, Davide M., et al.
(författare)
-
Why conservation biology can benefit from sensory ecology
- 2020
-
Ingår i: Nature Ecology & Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 4:4, s. 502-511
-
Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic sensory pollutants, such as noise, light and chemicals, are affecting biodiversity. This Perspective uses an understanding of animal sensory ecology to explore how these impacts can be mitigated. Global expansion of human activities is associated with the introduction of novel stimuli, such as anthropogenic noise, artificial lights and chemical agents. Progress in documenting the ecological effects of sensory pollutants is weakened by sparse knowledge of the mechanisms underlying these effects. This severely limits our capacity to devise mitigation measures. Here, we integrate knowledge of animal sensory ecology, physiology and life history to articulate three perceptual mechanisms-masking, distracting and misleading-that clearly explain how and why anthropogenic sensory pollutants impact organisms. We then link these three mechanisms to ecological consequences and discuss their implications for conservation. We argue that this framework can reveal the presence of 'sensory danger zones', hotspots of conservation concern where sensory pollutants overlap in space and time with an organism's activity, and foster development of strategic interventions to mitigate the impact of sensory pollutants. Future research that applies this framework will provide critical insight to preserve the natural sensory world.
|
|
| 4. |
- Marcusson-Clavertz, David, et al.
(författare)
-
Relationships between daily stress responses in everyday life and nightly sleep
- 2022
-
Ingår i: Journal of behavioral medicine. - : Springer. - 0160-7715 .- 1573-3521. ; 55, s. 518-532
-
Tidskriftsartikel (refereegranskat)abstract
- Stress and sleep are related, but the nature and time course of this relation is not well understood. We explored the within-person associations of three components of emotional responses to everyday stressors, indexed by negative affect, reactivity (initial response to a stressor), recovery (persistence of the post-stressor response), and pile-up (accumulation of stress episodes), with sleep indicators. We conducted coordinated analyses of data in several studies employing ecological momentary assessments, which captured naturally occurring, self-reported stress and sleep. We defined proximal reactivity as the emotional response to the stressor moment in question compared to an immediate pre-stressor state, and distal reactivity as the emotional response to the stressor moment in question compared to a typical stressor-free state for that person. Results in two of three studies showed that people reported significantly lower sleep quality following days on which they experienced higher levels of distal reactivity to stressors. Days with greater distal reactivity also predicted significantly more difficulty falling asleep in one of two studies. There was no clear association between proximal reactivity and subsequent sleep. Associations of recovery or pile-up with subsequent sleep emerged only in single studies. Poorer sleep quality was significantly related to higher next day levels of negative affect in all three studies, but there were no consistent relations between sleep and next day stress reactivity, recovery, or pile-up. These exploratory analyses suggest that distal reactivity is associated with a heightened risk of experiencing poor sleep quality the following night, and as such the former may serve as a candidate for potential targets for the remediation of the negative effects of stress on sleep.
|
|
| 5. |
- Doyle, S.J., et al.
(författare)
-
Magnetic equilibrium design for the SMART tokamak
- 2021
-
Ingår i: Fusion engineering and design. - : Elsevier BV. - 0920-3796 .- 1873-7196. ; 171, s. 112706-112706
-
Tidskriftsartikel (refereegranskat)abstract
- The SMall Aspect Ratio Tokamak (SMART) device is a new compact (plasma major radius Rgeo≥0.40 m, minor radius a≥0.20 m, aspect ratio A≥1.7) spherical tokamak, currently in development at the University of Seville. The SMART device has been designed to achieve a magnetic field at the plasma center of up to Bϕ=1.0 T with plasma currents up to Ip=500 kA and a pulse length up to τft=500 ms. A wide range of plasma shaping configurations are envisaged, including triangularities between −0.50≤δ≤0.50 and elongations of κ≤2.25. Control of plasma shaping is achieved through four axially variable poloidal field coils (PF), and four fixed divertor (Div) coils, nominally allowing operation in lower-single null, upper-single null and double-null configurations. This work examines phase 2 of the SMART device, presenting a baseline reference equilibrium and two highly-shaped triangular equilibria. The relevant PF and Div coil current waveforms are also presented. Equilibria are obtained via an axisymmetric Grad-Shafranov force balance solver (Fiesta), in combination with a circuit equation rigid current displacement model (RZIp) to obtain time-resolved vessel and plasma currents.
|
|
| 6. |
- Lenton, Timothy M., et al.
(författare)
-
A resilience sensing system for the biosphere
- 2022
-
Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 377:1857
-
Tidskriftsartikel (refereegranskat)abstract
- We are in a climate and ecological emergency, where climate change and direct anthropogenic interference with the biosphere are risking abrupt and/or irreversible changes that threaten our life-support systems. Efforts are underway to increase the resilience of some ecosystems that are under threat, yet collective awareness and action are modest at best. Here, we highlight the potential for a biosphere resilience sensing system to make it easier to see where things are going wrong, and to see whether deliberate efforts to make things better are working. We focus on global resilience sensing of the terrestrial biosphere at high spatial and temporal resolution through satellite remote sensing, utilizing the generic mathematical behaviour of complex systems—loss of resilience corresponds to slower recovery from perturbations, gain of resilience equates to faster recovery. We consider what subset of biosphere resilience remote sensing can monitor, critically reviewing existing studies. Then we present illustrative, global results for vegetation resilience and trends in resilience over the last 20 years, from both satellite data and model simulations. We close by discussing how resilience sensing nested across global, biome-ecoregion, and local ecosystem scales could aid management and governance at these different scales, and identify priorities for further work.
|
|
| 7. |
- Mancini, A., et al.
(författare)
-
Mechanical and electromagnetic design of the vacuum vessel of the SMART tokamak
- 2021
-
Ingår i: Fusion engineering and design. - : Elsevier BV. - 0920-3796 .- 1873-7196. ; 171
-
Tidskriftsartikel (refereegranskat)abstract
- The SMall Aspect Ratio Tokamak (SMART) is a new spherical device that is currently being designed at the University of Seville. SMART is a compact machine with a plasma major radius () greater than 0.4 m, plasma minor radius () greater than 0.2 m, an aspect ratio () over than 1.7 and an elongation () of more than 2. It will be equipped with 4 poloidal field coils, 4 divertor field coils, 12 toroidal field coils and a central solenoid. The heating system comprises of a Neutral Beam Injector (NBI) of 600 kW and an Electron Cyclotron Resonance Heating (ECRH) of 6 kW for pre-ionization. SMART has been designed for a plasma current () of 500 kA, a toroidal magnetic field () of 1 T and a pulse length of 500 ms preserving the compactness of the machine. The free boundary equilibrium solver code FIESTA [1] coupled to the linear time independent, rigid plasma model RZIP [2] has been used to calculate the target equilibria taking into account the physics goals, the required plasma parameters, vacuum vessel structures and power supply requirements. We present here the final design of the SMART vacuum vessel together with the Finite Element Model (FEM) analysis carried out to ensure that the tokamak vessel provides high quality vacuum and plasma performance withstanding the electromagnetic loads caused by the interaction between the eddy currents induced in the vessel itself and the surrounding magnetic fields. A parametric model has been set up for the topological optimization of the vessel where the thickness of the wall has been locally adapted to the expected forces. An overview of the new machine is presented here.
|
|
| 8. |
- Scott, Stacey B., et al.
(författare)
-
A Coordinated Analysis of Variance in Affect in Daily Life
- 2020
-
Ingår i: Assessment (Odessa, Fla.). - : Sage Publications. - 1073-1911 .- 1552-3489. ; 27:8, s. 1683-1698
-
Tidskriftsartikel (refereegranskat)abstract
- Despite widespread interest in variance in affect, basic questions remain pertaining to the relative proportions of between-person and within-person variance, the contribution of days and moments, and the reliability of these estimates. We addressed these questions by decomposing negative affect and positive affect variance across three levels (person, day, moment), and calculating reliability using a coordinated analysis of seven daily diary, ecological momentary assessment (EMA), and diary-EMA hybrid studies (across studies age = 18-84 years, totalN(persons)= 2,103, totalN(observations)= 45,065). Across studies, within-person variance was sizeable (negative affect: 45% to 66%, positive affect: 25% to 74%); in EMA more within-person variance was attributable to momentary rather than daily level. Reliability was adequate to high at all levels of analysis (within-person: .73-.91; between-person: .96-1.00) despite different items and designs. We discuss the implications of these results for the design of future intensive studies of affect variance.
|
|
| 9. |
- Abrams, Jesse F., et al.
(författare)
-
Committed Global Warming Risks Triggering Multiple Climate Tipping Points
- 2023
-
Ingår i: Earth's Future. - 2328-4277. ; 11:11
-
Tidskriftsartikel (refereegranskat)abstract
- Many scenarios for limiting global warming to 1.5(degrees)C assume planetary-scale carbon dioxide removal sufficient to exceed anthropogenic emissions, resulting in radiative forcing falling and temperatures stabilizing. However, such removal technology may prove unfeasible for technical, environmental, political, or economic reasons, resulting in continuing greenhouse gas emissions from hard-to-mitigate sectors. This may lead to constant concentration scenarios, where net anthropogenic emissions remain non-zero but small, and are roughly balanced by natural carbon sinks. Such a situation would keep atmospheric radiative forcing roughly constant. Fixed radiative forcing creates an equilibrium committed warming, captured in the concept of equilibrium climate sensitivity. This scenario is rarely analyzed as a potential extension to transient climate scenarios. Here, we aim to understand the planetary response to such fixed concentration commitments, with an emphasis on assessing the resulting likelihood of exceeding temperature thresholds that trigger climate tipping points. We explore transients followed by respective equilibrium committed warming initiated under low to high emission scenarios. We find that the likelihood of crossing the 1.5(degrees)C threshold and the 2.0(degrees)C threshold is 83% and 55%, respectively, if today's radiative forcing is maintained until achieving equilibrium global warming. Under the scenario that best matches current national commitments (RCP4.5), we estimate that in the transient stage, two tipping points will be crossed. If radiative forcing is then held fixed after the year 2100, a further six tipping point thresholds are crossed. Achieving a trajectory similar to RCP2.6 requires reaching net-zero emissions rapidly, which would greatly reduce the likelihood of tipping events.
|
|
| 10. |
- Li, Chen, et al.
(författare)
-
Genome-wide Association Analysis in Humans Links Nucleotide Metabolism to Leukocyte Telomere Length
- 2020
-
Ingår i: American Journal of Human Genetics. - : CELL PRESS. - 0002-9297 .- 1537-6605. ; 106:3, s. 389-404
-
Tidskriftsartikel (refereegranskat)abstract
- Leukocyte telomere length (LTL) is a heritable biomarker of genomic aging. In this study, we perform a genome-wide meta-analysis of LTL by pooling densely genotyped and imputed association results across large-scale European-descent studies including up to 78,592 individuals. We identify 49 genomic regions at a false dicovery rate (FDR) < 0.05 threshold and prioritize genes at 31, with five highlighting nucleotide metabolism as an important regulator of LTL. We report six genome-wide significant loci in or near SENP7, MOB1B, CARMIL1 , PRRC2A, TERF2, and RFWD3, and our results support recently identified PARP1, POT1, ATM, and MPHOSPH6 loci. Phenome-wide analyses in >350,000 UK Biobank participants suggest that genetically shorter telomere length increases the risk of hypothyroidism and decreases the risk of thyroid cancer, lymphoma, and a range of proliferative conditions. Our results replicate previously reported associations with increased risk of coronary artery disease and lower risk for multiple cancer types. Our findings substantially expand current knowledge on genes that regulate LTL and their impact on human health and disease.
|
|
