The Experts below are selected from a list of 50886 Experts worldwide ranked by ideXlab platform
A Bhattacharjee - One of the best experts on this subject based on the ideXlab platform.
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surface currents associated with external kink modes in tokamak plasmas during a Major Disruption
Physics of Plasmas, 2017Co-Authors: A BhattacharjeeAbstract:The surface current on the plasma-vacuum interface during a Disruption event involving kink instability can play an important role in driving current into the vacuum vessel. However, there have been disagreements over the nature or even the sign of the surface current in recent theoretical calculations based on idealized step-function background plasma profiles. We revisit such calculations by replacing step-function profiles with more realistic profiles characterized by a strong but finite gradient along the radial direction. It is shown that the resulting surface current is no longer a delta-function current density, but a finite and smooth current density profile with an internal structure, concentrated within the region with a strong plasma pressure gradient. Moreover, this current density profile has peaks of both signs, unlike the delta-function case with a sign opposite to, or the same as the plasma current. We show analytically and numerically that such current density can be separated into two pa...
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surface currents during a Major Disruption
2017Co-Authors: A BhattacharjeeAbstract:The surface current on the plasma-vacuum interface during a Disruption event involving kink instability can play an important role in driving current into the vacuum vessel. However, there have been disagreements over the nature or even the sign of the surface current in recent theoretical calculations based on idealized step-function background plasma profiles. We revisit such calculations by replacing step-function profiles with more realistic profiles characterized by strong but finite gradient along the radial direction. It is shown that the resulting surface current is no longer a delta-function current density, but a finite and smooth current density profile with internal structure, concentrated within the region with strong plasma pressure gradient. Moreover, this current density profile has peaks of both signs, unlike the delta-function case with a sign opposite to, or the same as the plasma current. We show analytically and numerically that such current density can be separated into two parts, with one of them, called the convective current density, describing the transport of the background plasma density by the displacement, and the other part that remains, called the residual current density. It is argued that consideration of both types of current density is important and can resolve past controversies.
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surface currents associated with external kink modes in tokamak plasmas during a Major Disruption
arXiv: Plasma Physics, 2017Co-Authors: A BhattacharjeeAbstract:The surface current on the plasma-vacuum interface during a Disruption event involving kink instability can play an important role in driving current into the vacuum vessel. However, there have been disagreements over the nature or even the sign of the surface current in recent theoretical calculations based on idealized step-function background plasma profiles. We revisit such calculations by replacing step-function profiles with more realistic profiles characterized by strong but finite gradient along the radial direction. It is shown that the resulting surface current is no longer a delta-function current density, but a finite and smooth current density profile with internal structure, concentrated within the region with strong plasma pressure gradient. Moreover, this current density profile has peaks of both signs, unlike the delta-function case with a sign opposite to, or the same as the plasma current. We show analytically and numerically that such current density can be separated into two parts, with one of them, called the convective current density, describing the transport of the background plasma density by the displacement, and the other part that remains, called the residual current density. It is argued that consideration of both types of current density is important and can resolve past controversies.
C A Blake - One of the best experts on this subject based on the ideXlab platform.
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Major Disruption of the pelvic ring during normal vaginal delivery a case report
SA Orthopaedic Journal, 2017Co-Authors: M Van Heukelum, C A BlakeAbstract:CITATION: Van Heukelum, M. & Blake, C. 2017. Major Disruption of the pelvic ring during normal vaginal delivery : a case report, SA Orthopaedic Journal, 16(1):24-27, doi:10.17159/2309-8309/2017/v16n1a2.
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Major Disruption of the pelvic ring during normal vaginal delivery
SA Orthopaedic Journal, 2017Co-Authors: M Van Heukelum, C A BlakeAbstract:Open-book pelvic fractures are generally associated with high energy trauma. Occasionally these fractures are seen as a complication of normal vaginal delivery. We report the case of a 25-year-old female with a 77 mm symphysis pubis diastasis with associated Disruption of the sacroiliac joints following delivery, which was successfully treated with open reduction and internal fixation.
F C Schuller - One of the best experts on this subject based on the ideXlab platform.
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high resolution temperature and density profiles during the energy quench of density limit Disruptions in rijnhuizen tokamak project
Physics of Plasmas, 2002Co-Authors: F Salzedas, F C Schuller, S Hokin, A A M OomensAbstract:Measurements of the electron temperature, Te, and density, ne, during the energy quench of a Major Disruption showed that the onset of Te erosion in the neighborhood of the m/n=2/1 O point at the low field side (LFS) accelerates the well-known m/n=1/1 erosion of the core temperature. During this phase Te(r) is only partially flat in the region between the q=2 and the q=1 surfaces and ne(r) decreases in the core and increases inside the m/n=2/1 island. Immediately after the flattening of Te(r) a large peak in Te and to a lesser extent in ne has been observed. This peak is radially localized at the q=2 radius at the LFS, is very short lived and is poloidally asymmetric. Te profiles measured by the heterodyne radiometer and the Thomson scattering agree very well up to the time Te(r) flattens but afterwards can be a factor of two different.
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the effect of ecrh on the stability of the radiation induced m 2 mode and on the current quench of a Major Disruption
Nuclear Fusion, 2002Co-Authors: F Salzedas, A A M Oomens, F C SchullerAbstract:The results of a series of experiments done in RTP which had the purpose to avoid or ameliorate radiative density-limit Disruptions, will be reported. Avoidance of Disruptions was achieved by stabilizing the m = 2 radiation induced tearing mode (RTM) with electron cyclotron resonance heating (ECRH). Both continuous and modulated power deposition was studied. It was found that stabilization with modulated ECRH in phase with the O-point was less efficient than continuous ECRH, contrary to theoretical expectations. Detailed scans of the EC power deposition and of the power intensity were in agreement with the assumption that radiative heat loss is the driving mechanism of this m = 2 mode. Amelioration of Disruptions was achieved, in a pilot experiment, by applying ECRH at the end of the energy quench. In this way, the current decay that follows a Major density-limit Disruption could be reversed.
Nicholas A. Tritos - One of the best experts on this subject based on the ideXlab platform.
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Pituitary society guidance: pituitary disease management and patient care recommendations during the COVID-19 pandemic—an international perspective
Pituitary, 2020Co-Authors: Maria Fleseriu, Michael Buchfelder, Pouneh K. Fazeli, Susana M. Mallea-gil, Ann Mccormack, Maria M. Pineyro, Luis V. Syro, Justin S Cetas, Mark Gurnell, Nicholas A. TritosAbstract:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the viral strain that has caused the coronavirus disease 2019 (COVID-19) pandemic, has presented healthcare systems around the world with an unprecedented challenge. In locations with significant rates of viral transmission, social distancing measures and enforced ‘lockdowns’ are the new ‘norm’ as governments try to prevent healthcare services from being overwhelmed. However, with these measures have come important challenges for the delivery of existing services for other diseases and conditions. The clinical care of patients with pituitary disorders typically involves a multidisciplinary team, working in concert to deliver timely, often complex, disease investigation and management, including pituitary surgery. COVID-19 has brought about Major Disruption to such services, limiting access to care and opportunities for testing (both laboratory and radiological), and dramatically reducing the ability to safely undertake transsphenoidal surgery. In the absence of clinical trials to guide management of patients with pituitary disease during the COVID-19 pandemic, herein the Professional Education Committee of the Pituitary Society proposes guidance for continued safe management and care of this population.
M Van Heukelum - One of the best experts on this subject based on the ideXlab platform.
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Major Disruption of the pelvic ring during normal vaginal delivery a case report
SA Orthopaedic Journal, 2017Co-Authors: M Van Heukelum, C A BlakeAbstract:CITATION: Van Heukelum, M. & Blake, C. 2017. Major Disruption of the pelvic ring during normal vaginal delivery : a case report, SA Orthopaedic Journal, 16(1):24-27, doi:10.17159/2309-8309/2017/v16n1a2.
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Major Disruption of the pelvic ring during normal vaginal delivery
SA Orthopaedic Journal, 2017Co-Authors: M Van Heukelum, C A BlakeAbstract:Open-book pelvic fractures are generally associated with high energy trauma. Occasionally these fractures are seen as a complication of normal vaginal delivery. We report the case of a 25-year-old female with a 77 mm symphysis pubis diastasis with associated Disruption of the sacroiliac joints following delivery, which was successfully treated with open reduction and internal fixation.
