9 research outputs found
The Young Child with Severe Obesity: Commentary on the Characteristics of a Vulnerable Population and a Framework for Treatment
It's Not You It's Me: Association Between Maternal Perceptions of Responsibility for Adolescents' Excess Weight and Pediatric Weight Management Program Attrition
Psychopathology and Adolescent Bariatric Surgery: A Topical Review to Support Psychologists in Assessment and Treatment Considerations.
Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak.
A new beam emission spectroscopy turbulence imaging system has recently been installed onto the MAST spherical tokamak. The system utilises a high-throughput, direct coupled imaging optics, and a single large interference filter for collection of the Doppler shifted D(α) emission from the ~2 MW heating beam of ~70 keV injection energy. The collected light is imaged onto a 2D array detector with 8 × 4 avalanche photodiode sensors which is incorporated into a custom camera unit to perform simultaneous 14-bit digitization at 2 MHz of all 32 channels. The array is imaged at the beam to achieve a spatial resolution of ~2 cm in the radial (horizontal) and poloidal (vertical) directions, which is sufficient for detection of the ion-scale plasma turbulence. At the typical photon fluxes of ~10(11) s(-1) the achieved signal-to-noise ratio of ~300 at the 0.5 MHz analogue bandwidth is sufficient for detection of relative density fluctuations at the level of a few 0.1%. The system is to be utilised for the study of the characteristics of the broadband, ion-scale turbulence, in particular its interaction with flow shear, as well as coherent fluctuations due to various types of MHD activity
Upstream and divertor ion temperature measurements on MAST by retarding field energy analyser
Dual view FIDA measurements on MAST
A fast-ion deuterium alpha (FIDA) spectrometer was installed on MAST to measure radially resolved information about the fast-ion density and its distribution in energy and pitch angle. Toroidally and vertically directed collection lenses are employed, to detect both passing and trapped particle dynamics, and reference views are installed to subtract the background. This background is found to contain a substantial amount of passive FIDA emission driven by edge neutrals, and to depend delicately on viewing geometry. Results are compared with theoretical expectations based on the codes NUBEAM (for fast-ion distributions) and FIDASIM. Calibrating via the measured beam emission peaks, the toroidal FIDA signal profile agrees with classical simulations in magnetohydrodynamic quiescent discharges where the neutron rate is also classical. Long-lived modes (LLMs) and chirping modes decrease the core FIDA signal significantly, and the profile can be matched closely to simulations using anomalous diffusive transport; a spatially uniform diffusion coefficient is sufficient for chirping modes, while a core localized diffusion is better for a LLM. Analysis of a discharge with chirping mode activity shows a dramatic drop in the core FIDA signal and rapid increase in the edge passive signal at the onset of the burst indicating a very rapid redistribution towards the edge. Vertical-viewing measurements show a discrepancy with simulations at higher Doppler shifts when the neutron rate is classical, which, combined with the fact that the toroidal signals agree, means that the difference must be occurring for pitch angles near the trapped-passing boundary, although uncertainties in the background subtraction, which are difficult to assess, may contribute to this. Further evidence of an anomalous transport mechanism for these particles is provided by the fact that an increase of beam power does not increase the higher energy vertical FIDA signals, while the toroidal signals do increase. © 2013 IOP Publishing Ltd
Costs of development and maintenance of an internet program for teens with type 1 diabetes
Dual view FIDA measurements on MAST
A Fast Ion Deuterium Alpha (FIDA) spectrometer was installed on MAST to
measure radially resolved information about the fast ion density and its
distribution in energy and pitch angle. Toroidally and vertically-directed
collection lenses are employed, to detect both passing and trapped particle
dynamics, and reference views are installed to subtract the background. This
background is found to contain a substantial amount of passive FIDA emission
driven by edge neutrals, and to depend delicately on viewing geometry. Results
are compared with theoretical expectations based on the codes NUBEAM (for fast
ion distributions) and FIDASIM. Calibrating via the measured beam emission
peaks, the toroidal FIDA signal profile agrees with classical simulations in
MHD quiescent discharges where the neutron rate is also classical. Long-lived
modes (LLM) and chirping modes decrease the core FIDA signal significantly, and
the profile can be matched closely to simulations using anomalous diffusive
transport; a spatially uniform diffusion coefficient is sufficient for chirping
modes, while a core localized diffusion is better for a LLM. Analysis of a
discharge with chirping mode activity shows a dramatic drop in the core FIDA
signal and rapid increase in the edge passive signal at the onset of the burst
indicating a very rapid redistribution towards the edge. Vertical viewing
measurements show a discrepancy with simulations at higher Doppler shifts when
the neutron rate is classical, which, combined with the fact that the toroidal
signals agree, means that the difference must be occurring for pitch angles
near the trapped-passing boundary. Further evidence of an anomalous transport
mechanism for these particles is provided by the fact that an increase of beam
power does not increase the higher energy vertical FIDA signals, while the
toroidal signals do increase.Comment: submitted to PPC