533 research outputs found
Asymmetric toroidal eddy currents (ATEC) to explain sideways forces at JET
During some JET vertical displacement events (VDEs) plasma current and position are
found to be toroidally asymmetric. When asymmetries lock, the vessel has been observed
to move horizontally, consequently strong horizontal forces are expected following plasma
asymmetries, whether locked or rotating. The cause of horizontal forces is, as already
identified in previous works, the asymmetric circulation of current in the structures. The
physics mechanism responsible for these asymmetric currents is instead an open issue and
it is the object of the present analysis. In particular it will be shown that the asymmetry is
not due to a direct exchange of current between plasma and structure (as in the case of halo
currents) but to asymmetric conductive paths which arise, in the structures, when the plasma
column asymmetrically wets the wall. Simulations of this phenomenon using finite element
(FE) models have been conducted to reproduce the JET observation during locked and rotating
asymmetric VDEs. Estimated sideways force, asymmetry (I p
asym) and normalized asymmetry
(Ap
asym) of plasma current, vertical position at different toroidal locations during the disruption
and halo current asymmetry have been compared with measurements done at JET during
upward AVDEs. The substantial match between experiments and simulations confirms the
soundness of the assumptions. Furthermore, the same physical model applied to downward
VDEs shows that divertor support and coils, together with the geometry of the limiting
surfaces, considerably lessen asymmetric loads as experienced at JET after installing those
components.EURATOM 63305
Do mental health and vitality mediate the relationship between perceived control over time and fear of COVID-19? A survey in an Italian sample
Several studies evidenced increased elevated symptomatology levels in anxiety, general stress, depression, and post-traumatic stress related to COVID-19. Real difficulties in the effective control of time that could be responsible for mental health issues and loss of vitality were also reported. Prior literature highlighted how perceived control over time significantly modulates anxiety disorders and promotes psychological well-being. To verify the hypothesis that perceived control over time predicts fear of COVID-19 and mental health and vitality mediate this relationship, we performed an online survey on a sample of 301 subjects (female = 68%; Mage = 22.12, SD = 6.29; age range = 18â57 years), testing a parallel mediation model using PROCESS macro (model 4). All participants responded to self-report measures of perceived control over time, COVID-19 fear, mental health, and vitality subscales of the Short-Form-36 Health Survey. Results corroborate the hypotheses of direct relationships between all the study variables and partially validate the mediationâs indirect effect. Indeed, mental health (a1b1 = â0.06; CI: LL = â0.11; UL = â0.01; p < 0.001) rather than vitality (a2b2 = â0.06; CI: LL = â0.09; UL = 0.03; n.s.) emerges as a significant mediator between perceived control over time and fear of COVID-19. Practical implications of the study about treatment programs based on perceived control over time and emotional coping to prevent fear and anxiety toward the COVID-19 pandemic are discussed
CPS Based Liquid Metal Divertor Target for EU-DEMO
AbstractPower exhaust is a key mission in the roadmap to the realization of a future fusion reactor. Among the different solutions, the use of liquid metals as plasma facing materials are of interest due to their potential increased lifetime. Several liquid metal limiters have been successfully tested in the Frascati Tokamak Upgrade over the last 10 years. Liquid materials such as lithium and tin have been investigated using capillary porous systems (CPSs), and their impact on plasma performance has been explored. From such experience, a liquid metal divertor (LMD) concept design, CPS-based, is here proposed. Tin has been preferred as plasma facing material. The proposed LMD would operate, in low evaporative regime, with matching heat exhausting capabilities to those of the baseline ITER-like divertor. Continuous refilling of the CPS is guaranteed with a reservoir at the back of the unit, where the metal is kept liquid through a gas heating circuit. The study has been carried out using ANSYS and the thermal results will be shown. All the design choices are compatible with the current materials and the constraints adopted for the DEMO W divertor. Using such configuration, thermal loads up to 20 MW/m2 are exhausted while keeping the surface temperature below 1250 °C. The design foresees values of pressure, temperature and flow rate of the water coolant in the same range expected for the W DEMO divertor, thus facilitating the integration of such solution in the current cassette design. Technological and practical aspects are addressed, i.e. tin corrosion and CPS wettability. Possible solutions to prevent tin corrosion, and its compatibility with structural materials, will be outlined
UAVIMALS: THE "OPEN" REMOTE SENSING SYSTEM FOR SURFACE ARCHAEOLOGICAL INVESTIGATIONS
Today, there is an increasing use of airborne sensors in archaeology, especially to investigate the surface of more or less vast territories quickly and accurately. In particular, airborne laser scanning technologies from small remotely piloted aircraft are rapidly developing towards increasingly high-performance solutions for the investigation of archaeological evidence hidden by vegetation or more or less substantial soil deposits. The proposed contribution intends to insert itself within this field of archaeological research by presenting "UAVIMALS" (Unmanned Aerial Vehicle Integrated with Micro Airborne Laser Scanner), an aerial remote sensing system of "soil marks", designed for surface archaeological investigations and the result of an Early Career Grant from the National Geographic Society. The system, consisting of a customised drone based on an open architecture and software for vehicle control and data processing, integrates a solid-state laser sensor, commonly engineered for obstacle avoidance, but here exploited to process accurate DTM (Digital Terrain Model) of small land surfaces with a significant reduction in cost and acquisition time. The system, whose engineering was contributed by the BioRobotics Institute of the S. Anna University of Pisa, was tested within the archaeological context of Leopoli - Cencelle (Tarquinia, Italy). A mediaeval city that has been researched for about 25 years by the Chair of Christian and Medieval Archaeology at the 'Sapienza' University of Rome. Experimentation missions carried out on the site, which is still only partially investigated, have been successful in bringing to light some urban areas that had not yet been investigated
Sensory-Adapted Dental Environment for the Treatment of Patients with Autism Spectrum Disorder
Purpose: The importance of dental care and oral hygiene is often underestimated in people with autism spectrum disorder (ASD). Comorbidity with dental anxiety is greater in ASD subjects who also show unusual reactions to sensory stimuli. The aim of our study was to assess the efficacy for a sensory-adapted environment and targeted methods in reducing anxiety and positively influencing cooperation in children with ASD during a dental examination or specific treatments. Material and methods: The sample consisted of 50 Italian children with a diagnosis of ASD (36 males and 14 females; aged 9â10 years) presenting with mild intellectual disability (ID) and verbal language skills. The subjects enrolled in the study had at least two decayed teeth and all were treated in two different dental environments: regular dental environment (RDE) and sensory-adapted dental environment (SADE). Results: 20% of the sample was successfully treated in RDE, while 68% of subjects were successfully treated in SADE. Conclusions: Results suggest that a sensory-adapted environment positively affects the therapeutic dental treatment in patients with ASD and reaffirm that sensory dysregulation in children with ASD is a crucial factor influencing the successful outcome of oral care
Does attentional style moderate the relationship between time perspective and social network addiction? A crossâsectional study on a sample of social networking sites users
The present study investigates the role of attentional style as a moderator variable between temporal perspective and social network addiction, since little is known about usersâ cognitive variables involved in this kind of addictive behavior. To achieve this goal, a sample of 186 volunteers and anonymous social networking sites users (M = 34%; F = 66%; Mage = 22.54 years; SD = 3.94; range: 18 Ă· 45 years) participated in a crossâsectional study. All participants filled out self-report instruments measuring temporal perspective, internal vs. external attentional style, and social network addiction. The results align with the previous literature and show that present fatalistic and past negative time orientations are associated with social network addiction, whereas the future is a negative precursor. Moreover, a fourâstep hierarchical regression analysis showed that internal attentional style is a significant moderator of the relationship between high levels of temporal perspective and a high level of social network addiction. This result suggests that social networkâaddicted users are oriented toward internal stimuli such as their intrusive thoughts or feelings and that social network addiction is similar to obsessive compulsive disorders, depression, or anxiety. Despite its limitations, the present study could contribute to the efforts of clinicians, psychiatrists, psychologists, teachers, and all those who seek to combat social network addiction in developing treatment programs to reduce its harmful effects
Temperamental characteristics in childhood migraine without aura:A multicenter study
Background: Children with migraine seem to be more anxious, sensitive, deliberate, cautious, fearful, vulnerable to frustration, tidy, and less physically enduring than comparisons. To the best our knowledge no studies about the temperamental and the characterial dimension aspects in childhood migraine was conducted. Therefore, the aim of the present study was to describe the temperamental and character aspects in a sample of children affected by migraine without aura (MoA) and their relationship with clinical aspects of MoA such as frequency, duration, and severity of attacks. Materials and methods: In our study, 486 children affected by MoA (239 male, 247 female) aged 7-12 years, (mean 10.04 \ub1 2.53 years) and 518 typical developing children comparable for age (P = 0.227) and sex (P = 0.892) were enrolled to assess their temperamental characteristics. The mothers of all subjects filled out the Junior Temperament and Character Inventory: Parent Version. Results: Children affected by migraine show a higher prevalence of harm avoidance and persistence temperamental domains (P, 0.001) and significantly lower prevalence of the self-directedness character trait (P = 0.023) with respect to the comparisons, according to Cloninger's model. The Spearman rank correlation analysis shows a significant relationship between migraine characteristics and temperamental domains. Conclusion: The present study first identified differences in temperamental characteristics in children affected by MoA with respect to the comparisons, suggesting the need for this evaluation in order for better psychological pediatric management of children with migraine, with possible consequences and impact on the future outcomes of these subjects
Particle acoustic detection in gravitational wave aluminum resonant antennas
The results on cosmic rays detected by the gravitational antenna NAUTILUS
have motivated an experiment (RAP) based on a suspended cylindrical bar, which
is made of the same aluminum alloy as NAUTILUS and is exposed to a high energy
electron beam. Mechanical vibrations originate from the local thermal expansion
caused by warming up due to the energy lost by particles crossing the material.
The aim of the experiment is to measure the amplitude of the fundamental
longitudinal vibration at different temperatures. We report on the results
obtained down to a temperature of about 4 K, which agree at the level of about
10% with the predictions of the model describing the underlying physical
process.Comment: RAP experiment, 16 pages, 7 figure
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