Lost alpha Faraday cup foil noise characterization during Joint European Torus plasma post-processing analysis.

Capacitive plasma pickup is a well-known and difficult problem for plasma-facing edge diagnostics. This problem must be addressed to ensure an accurate and robust interpretation of the real signal measurements vs noise. The Faraday cup fast ion loss detector array of the Joint European Torus (JET) is particularly prone to this issue and can be used as a testbed to prototype solutions. The issue of separation and distinction between warranted fast ion signal and electromagnetic plasma noise has traditionally been solved with hardware modifications, but a more versatile post-processing approach is of great interest. This work presents post-processing techniques to characterize the signal noise. While hardware changes and advancements may be limited, the combination with post-processing procedures allows for more rapid and robust analysis of measurements. The characterization of plasma pickup noise is examined for alpha losses in a discharge from JET's tritium campaign. In addition to highlighting the post-processing methodology, the spatial sensitivity of the detector array is also examined, which presents significant advantages for the physical interpretation of fast ion losses.

Improvements to the Faraday cup fast ion loss detector and magnetohydrodynamic induced fast ion loss measurements in Joint European Torus plasmas.

Upgrades to electronic hardware and detector design have been made to the JET thin-foil Faraday cup fast ion loss detector [Darrow et al., Rev. Sci. Instrum. 75, 3566 (2004)] in anticipation of the upcoming deuterium-tritium (DT) campaign. An improved foil stack design has been implemented, which greatly reduces the number of foil-to-foil shorts, and triaxial cabling has mitigated ambient noise pickup. Initial tests of 200 kHz digitizers, as opposed to the original 5 kHz digitizers, have provided enhanced analysis techniques and direct coherence measurements of fast ion losses with magnetohydrodynamic activity. We present recent loss measurements in JET deuterium plasmas correlated with kink modes, fishbone modes, edge-localized modes, and sawteeth. Sources of systematic noise are discussed with emphasis on capacitive plasma pickup. Overall, the system upgrades have established a diagnostic capable of recording alpha particle losses due to a wide variety of resonant fast ion transport mechanisms to be used in future DT-experiments and modeling efforts.

Droplet sizing with a wavelength modulated laser.

The light scattered by spherical droplets much larger than the wavelength may be modeled with rays associated with scattering orders that follow the laws of geometrical optics. These rays travel different paths as they are reflected and refracted by the droplet. Therefore, there is an optical pathlength difference (OPD) between these rays as they arrive on the detector. By illuminating the droplet with a frequency or wavelength modulated laser, the OPD of any pair of rays can be measured from the beat frequency that results when the rays interfere on the detector. Sweep wavelength lasers are well suited for this application given their rapid sweep rate and broad sweep wavelength band.

What effect will a few degrees of climate change have on human heat balance? Implications for human activity.

While many factors affecting human health that will alter with climate change are being discussed, there has been no discussion about how a warmer future will affect man's thermoregulation. Using historical climate data for an Australian city and projections for Australia's climate in 2070, we address the issue using heat balance modelling for humans engaged in various levels of activity from rest to manual labour. We first validate two heat balance models against empirical data and then use the models to predict the number of days at present and in 2070 that (1) sweating will be required to attain heat balance, (2) heat balance will not be possible and hyperthermia will develop, and (3) body temperature will increase by 2.5°C in less than 2 h, which we term "dangerous days". The modelling is applied to people in an unacclimatised and an acclimatised state. The modelling shows that, for unacclimatised people, outdoor activity will not be possible on 33-45 days per year, compared to 4-6 days per year at present. For acclimatised people the situation is less dire but leisure activity like golf will be not be possible on 5-14 days per year compared to 1 day in 5 years at present, and manual labour will be dangerous to perform on 15-26 days per year compared to 1 day per year at present. It is obvious that climate change will have important consequences for leisure, economic activity, and health in Australia.

The anomalous currents in the front foils of the JET lost alpha diagnostic KA-2.

We have examined the observed currents in the front foils of the JET Faraday cup lost alpha particle diagnostic KA-2. In particular, we have sought to understand the currents during Ohmic plasmas for which the ion flux at the detectors was initially assumed to be negligible. We have considered two sources of this current: plasma ions (both deuterium and impurity) in the vicinity of the detector (including charge exchange neutrals) and photoemission from scattered UV radiation. Based upon modeling and empirical observation, the latter source appears most likely and, moreover, seems to be applicable to the currents in the front foil during ELMy H-mode plasmas. A very thin gold or nickel foil attached to the present detector aperture is proposed as a solution to this problem, and realistic calculations of expected fluxes of lost energetic neutral beam ions during TF ripple experiments are presented as justification of this proposed solution.

Observation of alpha particle loss from JET plasmas during ion cyclotron resonance frequency heating using a thin foil Faraday cup detector array.

The loss of MeV alpha particles from JET plasmas has been measured with a set of thin foil Faraday cup detectors during third harmonic heating of helium neutral beam ions. Tail temperatures of ∼ 2 MeV have been observed, with radial scrape off lengths of a few centimeters. Operational experience from this system indicates that such detectors are potentially feasible for future large tokamaks, but careful attention to screening rf and MHD induced noise is essential.

Dogs and goats as sentinels for environmental lead burden in Caribbean basin islands: Jamaica West Indies

Ingested/inhaled environmental lead (Pb) continues to pose a health risk to humans (children in particular) and animals. Automobile emissions from leaded gasoline combustion (less of a problem today with the phasing out of leaded gasoline), lead contaminated foods, soil and water, lead-based paints, ceramics, batteries (more frequently encountered today), and possible electronic waste, remain major sources of environmental lead. In a study carried out in Jamaica, West Indies, blood samples from dogs (n=63 at 5 locations) and goats (n=46 at 4 locations) were collected in lead-free (EDTA) tubes and analyzed by graphite furnace atomic absorption spectrometry (GFAAS) for lead. The analytical method detection limit was 0.24 μg/dl. Overall (blood lead) PbB concentrations were 2.83 ñ 2.96 μg/dl (dogs), and 1.02 ñ 0:10 μg/dl (goats). There were significant differences among locations, and. in a location of high automobile and plant foliage/grass forage density, PbB levels were 7.03 ñ 2.96 μg/dl (n=8) and 1.91 ñ 0.83 μg/d1 (n=10) in dogs and goats respectively. Although sample sizes are small the results suggest the use of dogs and goats as sentinels for evaluating environmental lead in developing countries.

Abdominal fat necrosis in a pygmy goat associated with fescue toxicosis.

Abdominal fat necrosis was diagnosed in an 11-year-old female pygmy goat with a 10-day history of lethargy, anorexia, and progressive abdominal distension. Gross necropsy findings revealed multiple firm, dark yellow, nodular masses of fat throughout the abdominal cavity, which compressed several abdominal organs including the rumen, small intestine, spiral colon, and gall bladder. Histologically, multiple to coalescing adipocyte necrosis, saponification, and infiltration with variable numbers of macrophages, lymphocytes, and plasma cells was observed. Fat necrosis in this case was attributed to tall fescue toxicity based on the presence of high levels of endophyte (Neotyphodium coenophialum)-infected fescue identified in the goat's pasture. This is the first known report of abdominal fat necrosis in a goat and demonstrates the fat necrosis syndrome of fescue toxicosis in ruminants.

Spectrophotometric analysis of solubilized rat hair proteins following intraperitoneal injection of 2,5-hexanedione.

The neurotoxic industrial solvents n-hexane and methyl n-butyl ketone are toxic by virtue of their common metabolite, 2,5-hexanedione (2,5-HD). Our previous work showed that pyrrole-like substances in solubilized rat hair proteins from rats injected (ip) daily with 2,5-HD demonstrated maximal absorbance in the 530-nm spectral region following reaction with Ehrlich's reagent (p-dimethylaminobenzaldehyde). Modification of the current analytical methods of achieving high specificity and lower detection limits with small sample quantities could have important implications for monitoring human populations. Adult male Sprague-Dawley rats were housed in individual metabolic cages with food and water provided ad libitum. Individual rats were injected (ip) daily with either 50 mg/kg 2,5-HD or physiologic-buffered saline (PBS). Plucked hair samples (dorsal, right flank, and left flank) were obtained from each rat before and at 7-day intervals after exposure to 2,5-HD or PBS for 28 days. Hair proteins solubilization and extraction procedures were adapted from earlier studies. We read 1 mL of dialyzed hair protein solution (2,5-HD or PBS control) against a reference cuvette containing water. Analyses utilized a Shimadzu UV 160 V recording spectrophotometer at an absorbency spectral range of 450 to 600 nm. In all spectral tracings, absorbance maxima (at 530 nm) characteristic of pyrrole-like substances were detected only in samples from 2,5-HD-treated rats. Absorbance at 530 nm was detected starting at Day 7 after exposure. The authors acknowledge Dr. Richard Whorton and Dr. Barbara Buckley for advice and for the use of their spectrophotometric equipment and Dr. Lowell A. Goldsmith for his help in our choice of the subject studied. This work was supported by the Walter P. Inman Memorial Fund in an award from Duke University to Dr. Leon Lack.