| 11. |
- Barakat, M. M. E., et al.
(författare)
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Superconducting gap and critical behavior in the Iron-Pnictides
- 2023
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Ingår i: RESULTS IN PHYSICS. - : ELSEVIER. - 2211-3797. ; 52
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Tidskriftsartikel (refereegranskat)abstract
- In the phase diagram of iron pnictides, superconductivity arises at the border of antiferromagnetism, which raises the question of the role of symmetry of the gap and quantum criticality. Although more than 15-years of extensive research, the microscopic origin of the pairing symmetry inside the superconducting (SC) dome and its link to quantum criticality still remains elusive. Here, we report two new findings on BaFe2_xNixAs2: (1) A sharp peak in the x-dependence of the lower and upper critical fields, the SC critical current density Jc, the size of the jump in the specific heat Delta Cel/T and the Sommerfeld coefficient (gamma) at the optimum composition x = 0.10, where the SC transition temperature Tc reaches a maximum. Our obtained reliable values as a function of doping of the normal-state Sommerfeld coefficient increase with doping, illustrating the strong competition between magnetism and superconductivity and attributed to closing of spin density wave gap with Ni doping. (2) We show that doping induced a sudden change of the gap structure from nodeless to nodal. Our results imply that the superconductivity in BaFe2_xNixAs2 is closely linked to the quantum criticality and is characterized by a complex order parameter.
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| 18. |
- Etbaeitabari, Amir, et al.
(författare)
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An analytical heat transfer assessment and modeling in a natural convection between two infinite vertical parallel flat plates
- 2013
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Ingår i: Journal of Molecular Liquids. - : Elsevier. - 0167-7322 .- 1873-3166. ; 188, s. 252-257
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Tidskriftsartikel (refereegranskat)abstract
- Heat transfer by natural convection occurs in many physical problems and engineering applications such as geo-thermal systems, heat exchangers, petroleum reservoirs and nuclear waste repositories. These problems and phenomena are modeled by ordinary or partial differential equations. In most cases, experimental solutions cannot be applied to these problems, so these equations should be solved using special techniques. Recently, much attention has been devoted to these methods to construct analytic solutions; such as the perturbation method. Perturbation techniques are dependent upon small parameter. Thus, it is worthwhile developing a new technique independent of small parameter. The Reconstruction of Variational Iteration Method technique is a powerful and convenient algorithm in finding the solutions for the equations. While this method is capable of reducing the size of calculation, it overcomes the difficulty of the perturbation technique or Adomian polynomials by applying Laplace Transform. In this paper an analysis has been performed to study the natural convection of a non-Newtonian fluid between two infinite parallel vertical flat plates and the effects of the non-Newtonian nature of fluid on the heat transfer are studied. In order to compare with exact solution, velocity and temperature profiles are shown graphically. The obtained results are valid with significant accuracy. (C) 2013 Elsevier B.V. All rights reserved.
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| 19. |
- Haaland, S., et al.
(författare)
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Estimation of cold plasma outflow during geomagnetic storms
- 2015
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Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 120:12, s. 10622-10639
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Tidskriftsartikel (refereegranskat)abstract
- Low-energy ions of ionospheric origin constitute a significant contributor to the magnetospheric plasma population. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and typically in regions of space where spacecraft attain a positive charge due to solar illumination. Cold ions are therefore shielded from the satellite particle detectors. Furthermore, spacecraft can only cover key regions of ion outflow during segments of their orbit, so additional complications arise if continuous longtime observations, such as during a geomagnetic storm, are needed. In this paper we suggest a new approach, based on a combination of synoptic observations and a novel technique to estimate the flux and total outflow during the various phases of geomagnetic storms. Our results indicate large variations in both outflow rates and transport throughout the storm. Prior to the storm main phase, outflow rates are moderate, and the cold ions are mainly emanating from moderately sized polar cap regions. Throughout the main phase of the storm, outflow rates increase and the polar cap source regions expand. Furthermore, faster transport, resulting from enhanced convection, leads to a much larger supply of cold ions to the near-Earth region during geomagnetic storms.
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| 20. |
- Mahameed, Haneen, et al.
(författare)
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Previous Vaccination History and Psychological Factors as Significant Predictors of Willingness to Receive Mpox Vaccination and a Favorable Attitude towards Compulsory Vaccination
- 2023
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Ingår i: Vaccines. - 2076-393X. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- During the ongoing multi-country monkeypox (Mpox) outbreak, healthcare workers (HCWs) have represented a key group in mitigating disease spread. The current study aimed to evaluate the attitude of nurses and physicians in Jordan towards Mpox vaccination, as well as their attitude towards compulsory vaccination against coronavirus disease 2019 (COVID-19), influenza, and Mpox. An online survey was distributed in January 2023 based on the previously validated 5C scale for psychological determinants of vaccination. Previous vaccination behavior was assessed by inquiring about the history of getting the primary and booster COVID-19 vaccination, influenza vaccine uptake during COVID-19, and any history of influenza vaccine uptake. The study sample consisted of 495 respondents: nurses (n = 302, 61.0%) and physicians (n = 193, 39.0%). Four hundred and thirty respondents (86.9%) had heard of Mpox before the study, and formed the final sample considered for Mpox knowledge analysis. Deficiencies in Mpox knowledge were reflected in a mean knowledge score of 13.3 ± 2.7 (out of 20.0 as the maximum score), with significantly lower knowledge among nurses and females. The intention to receive Mpox vaccination was reported by 28.9% of the participants (n = 143), while 33.3% were hesitant (n = 165), and 37.8% were resistant (n = 187). In multivariate analysis, Mpox vaccine acceptance was significantly associated with previous vaccination behavior, reflected in higher vaccine uptake and with higher 5C scores, while Mpox knowledge was not correlated with Mpox vaccination intention. The overall attitude towards compulsory vaccination was neutral, while a favorable attitude towards compulsory vaccination was associated with higher 5C scores and a history of previous vaccination uptake. The current study showed a low intention to get Mpox vaccination in a sample of nurses and physicians practicing in Jordan. The psychological factors and previous vaccination behavior appeared as the most significant determinants of Mpox vaccine acceptance and of attitudes towards compulsory vaccination. The consideration of these factors is central to policies and strategies aiming to promote vaccination among health professionals in efforts to prepare for future infectious disease epidemics.
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