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Träfflista för sökning "WFRF:(Åkerstedt Henrik) srt2:(2020-2024)"

Sökning: WFRF:(Åkerstedt Henrik) > (2020-2024)

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1.
  • Isomura, Kayoko, et al. (författare)
  • Insomnia in Tourette Syndrome and Chronic Tic Disorder
  • 2022
  • Ingår i: Movement Disorders. - : John Wiley & Sons. - 0885-3185 .- 1531-8257. ; 37:2, s. 392-400
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Insomnia is common in Tourette syndrome (TS) and chronic tic disorder (CTD), but precise prevalence estimates are lacking.OBJECTIVE: In this Swedish register-based cohort study, we estimated the prevalence of insomnia in TS/CTD and quantified the magnitude of this association, accounting for familial confounders and relevant somatic and psychiatric comorbidities.METHODS: Of 10,444,702 individuals living in Sweden during the period from 1997 to 2013, 5877 had a diagnosis of TS/CTD and were compared to unexposed individuals from the general population on the presence of insomnia using logistic regression models.RESULTS: Individuals with TS/CTD had a period prevalence of insomnia of 32.16%, compared to 13.70% of the unexposed population. This translated into a 6.7-fold increased likelihood of insomnia in TS/CTD (odds ratio adjusted [aOR] for sex, birth year, birth country, and somatic disorders = 6.74; 95% confidence interval [CI], 6.37-7.15). A full sibling comparison, designed to adjust for shared familial factors, attenuated the estimates (aOR = 5.41; 95% CI, 4.65-6.30). When individuals with attention-deficit/hyperactivity disorder (ADHD) and pervasive developmental disorders were excluded, the association was also attenuated, whereas exclusion of other psychiatric comorbidities had minimal impact. Having persistent TS/CTD, comorbid ADHD, and taking ADHD medication greatly increased the likelihood of insomnia.CONCLUSIONS: Insomnia is significantly associated with TS/CTD, independently from somatic disorders, familial factors or psychiatric comorbidities, although familial factors, neurodevelopmental comorbidities, and ADHD/ADHD medication may explain part of the association. Insomnia should be routinely assessed and managed in TS/CTD, particularly in chronic patients and in those with comorbid ADHD. Other sleep disorders require further study. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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2.
  • Sevilla-Cermeño, Laura, et al. (författare)
  • Insomnia in obsessive-compulsive disorder : A Swedish population-based cohort study
  • 2020
  • Ingår i: Journal of Affective Disorders. - : Elsevier. - 0165-0327 .- 1573-2517. ; 266, s. 413-416
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: The association between specific psychiatric disorders and insomnia is well established, but the prevalence of insomnia in obsessive-compulsive disorder (OCD) is unknown. This population-based study examined the prevalence of insomnia in patients with OCD compared to unaffected individuals from the general population and to their unaffected full siblings, and evaluated the contribution of psychiatric comorbidities to this association.METHODS: Individuals diagnosed with OCD (31,856) were identified from a cohort of 13,017,902 individuals living in Sweden anytime during 1973 and 2013. Logistic regression analyses were used to investigate the odds of insomnia in individuals with OCD, compared to the general population and their unaffected full siblings. Sensitivity analyses were performed in subgroups from which all individuals with comorbid psychiatric conditions were excluded, one at a time.RESULTS: Individuals with OCD had almost 7-fold increased odds of receiving an insomnia diagnosis or being dispensed a drug with specific indication for insomnia, compared to unaffected individuals from the general population (42.2% vs. 11.0%, respectively; OR=6.92 [95% CI, 6.76-7.08]). Familiar factors shared with siblings and comorbid conditions did not fully explain this association, but when individuals with comorbid depression and anxiety disorders were excluded, the odds of insomnia were significantly reduced (OR=4.97 [95% CI, 4.81-5.14] and OR=4.51 [95% CI, 4.33-4.69], respectively).LIMITATIONS: Due to the intrinsic coverage issues of the registers, results may not be generalizable to milder forms of the disorder and to individuals who do not seek help.CONCLUSIONS: Insomnia should be systematically evaluated and managed in individuals with OCD, particularly in those with comorbid anxiety and depression.
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4.
  • Siddanathi, Likitha Sai, et al. (författare)
  • Computational modeling and temperature measurements using emission spectroscopy on a non-transferred plasma torch
  • 2023
  • Ingår i: AIP Advances. - : American Institute of Physics Inc.. - 2158-3226. ; 13:2
  • Tidskriftsartikel (refereegranskat)abstract
    • A non-transferred plasma torch is a device used to generate a steady thermal plasma jet. Plasma torches have the potential to replace fossil fuel burners used as heat sources in the process industry. Today, however, the available plasma torches are of small scale compared to the power used in the burners in the process industry. In order to understand the effects of large scales on the plasma flow dynamics, it is essential to understand the operation of the plasma torch under different operating conditions and for different geometries. In this study, the analysis of a non-transferred plasma torch has been carried out using both computational and experimental methods. Computationally, the magnetohydrodynamic (MHD) equations are solved using a single-fluid model on a 2D axisymmetric torch geometry. The experiments are performed using emission spectroscopy to measure the plasma jet temperature at the outlet. This paper explains the changes in the arc formation, temperature, and velocity for different working gases and power inputs. Furthermore, the possibilities and disadvantages of the MHD approach, considering a local thermal equilibrium, are discussed. It was found that in general, the computational temperature obtained is supported by the experimental and equilibrium data. The computational temperatures agree by within 10% with the experimental ones at the center of the plasma torch. The paper concludes by explaining the significant impact of input properties like working gas and power input on the output properties like velocity and temperature of plasma jet. © 2023 Author(s).
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5.
  • Siddanathi, Likitha Sai, et al. (författare)
  • Computational Modeling of a Plasma Torch Using Single-Fluid and Two-Fluid Modeling Approaches
  • 2023
  • Ingår i: COMSOL Conference 2023. - : COMSOL.
  • Konferensbidrag (refereegranskat)abstract
    • Plasma, a complex fluid consisting of electrons, ions, neutrals, and excited species, exhibits both fluid-like behavior and electrical conductivity due to the presence of charge carriers. Consequently, computational modeling of plasma requires the integration of fluid and electrical models. This research paper presents a study on the steady-state computational modeling of a plasma torch with a 2D axisymmetric geometry using single-fluid and two-fluid modeling approaches in the COMSOL Multiphysics® software. The single-fluid modeling (SFM) approach combines the individual equations governing the behavior of different particles into a unified equation. Specifically, the SFM approach utilized in this study focuses on a fully ionized plasma and employs the Magnetohydrodynamic equations whose adaptation is equilibrium discharge interface (EDI) model available in COMSOL Multiphysics®. The EDI model solves the magnetohydrodynamic (MHD) equations, encompassing electric and magnetic fields, heat transfer in solids and fluids, and laminar models. By employing this approach, the researchers simulated and analyzed the behavior of the plasma torch. In contrast, the two-fluid modeling (TFM) approach separates the fluid equations for electrons and ions, considering a weakly ionized plasma. The TFM model is developed by deriving fluid equations based on kinetic theory for neutrals, ions, and electrons. These equations are then implemented in COMSOL Multiphysics®, utilizing models for the transport of diluted species, laminar flow, heat transfer in solids and fluids, and electric and magnetic fields. By adopting the TFM approach, the researchers aimed to gain insights into the behavior of the plasma torch. Throughout the study, various properties such as temperature, velocity, current density, and particle concentrations are analyzed within the plasma torch. Results obtained from both the single-fluid and two-fluid modeling approaches are compared and evaluated. This comparative analysis allows the researchers to highlight the advantages and challenges associated with each modeling approach. In conclusion, this study contributes to understanding plasma behavior by employing computational modeling techniques. The research presents and compares the outcomes of single-fluid and two-fluid modeling approaches applied to a plasma torch. By examining the advantages and challenges of each approach, the study offers valuable insights for future plasma modeling endeavors.
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6.
  • Siddanathi, Likitha Sai, et al. (författare)
  • Modelling of heat flow and electromagnetic phenomena in a non-transferred plasma torch
  • 2021
  • Ingår i: 47<sup>th</sup> EPS Conference on Plasma Physics 21 - 25 June 2021. - : European Physical Society. - 9781713837046
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Over the decades, computational methods have been used to model and describe the flow andionization dynamics in plasma torches. However, the impact of the operational parameters such as gas flow rate, swirl number and input current density on flow is still inexplicit. In this study, the flow in a non-transferred plasma torch is modelled using COMSOL Multiphysics, and the influence of these parameters is studied. The analysis is carried out on an axisymmetric geometry with the conical-shaped cathode, nozzle-shaped anode, and Argon is used as the plasma gas. A thermal plasma (equilibrium discharges) is considered, i.e., the plasma is underpartial to complete local thermodynamic equilibrium in which the magnetohydrodynamic (MHD) equations are solved. This is treated in the Equilibrium Discharge Interface in COMSOL’s plasma module that has been used in the present study. The laminar flow analysisis performed for low-velocity cases and turbulent flow analysis for higher velocities. It was found that the velocity increase across the plasma arc due to ionization and gas expansion, couldbe observed only for sufficiently high plasma inflow velocities. The position of the plasma arcis determined for different operating conditions. It was further found that the velocity has anegligible effect on the length of the plasma arc, whereas the dependency of the arc length andattachment point on the anode wall, to the input current density and cathode tip temperature iswell explained. The paper concludes by presenting the variations in temperature and velocityof plasma arc due to swirling inflow.
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7.
  • Åkerstedt, Henrik (författare)
  • Demonstrating reliableinstrumentation in theATLAS Tile Calorimeter : Fault tolerance and redundancy in hardware and firmwarefor the Phase-II Demonstrator project in preparation forHigh Luminosity LHC at CERN
  • 2024
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The Large Hadron Collider at CERN is scheduled to undergo upgrades in 2026-2028 to significantly increase its luminosity. These upgrades, while providing the experiments with a higher collision rate, pose a number of challenges to the design of the hardware and software in the detectors. The Tile Calorimeter (a scintillating sampling calorimeter read out by photomultiplier tubes) at the ATLAS experiment will have its read-out electronics completely replaced to enable performance and reliability improvements. Advances in electronics, new requirements due to the luminosity upgrade as well as lessons learned from the current readout scheme drove development with the goals to partition the readout into small independent units with full granularity readout and a robust mitigation strategy for radiation induced errors. To verify the functionality of the new system while retaining backward compatibility a "Demonstrator'' has been developed to emulate the current functionality while using new and improved hardware.The board responsible for managing digitized calorimeter data and communicating with the off-detector electronics, called the DaughterBoard, is the main focus of this thesis. It has two electrically isolated sides for redundancy where each side consists of voltage regulators, two optical transceivers, a GigaBit transceiver chip (for clocking and configuration) and a Kintex FPGA for data processing.In addition to data management and transmission, the FPGA (and every other component) needs to be able to withstand the effects of radiation both in terms of total dose (ionization and displacement damage) and due to single event effects. The DaughterBoard was developed with this in mind and has undergone several radiation tests during its development to verify reliability and fault tolerance.
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