The plasma jet: industrial hygiene aspects and a survey of current United States practices for employee protection.
Abstract The plasma torch, because it concentrates large amounts of thermal energy in a small volume, has become increasingly popular in industry. During the past fifteen years, the plasma torch has developed into an important industrial tool, and it has been used for metal cutting and welding fabricating operations that would not be possible otherwise. However, along with technological advances, the plasma torch has presented new problems to the industrial hygiene field. It is the purpose of this paper to discuss these problems and the extent of industrial hygienist's awareness of them. A brief outline of the theory of the plasma torch and the history and scope of its industrial usage is also presented.
Investigative studies of plasma torch hazards.
Abstract Potential health hazards from a medium output plasma torch used in a biological laboratory were investigated, and some industrial applications of higher output plasma torches were surveyed. Exposures to intense ultraviolet radiation, noise, and noxious gases and fumes were measured. Biological experiments on animals and human skin were performed to evaluate the reaction to ultraviolet energy, and thermocouples were used to quantirate the thermal reaction of skin and eyes produced by the plasma torch.
Imaging the Internal Structure of an Alpine Glacier via L-Band Airborne SAR Tomography
In this paper, we report results from the analysis of 3-D L-band airborne synthetic aperture radar (SAR) acquisitions acquired in March 2014 over the Mittelbergferner glacier, Austrian Alps, during the European Space Agency (ESA) campaign AlpTomoSAR. The campaign included coincident in situ measurements of snow and ice properties and ground-penetrating radar (GPR) data acquired at 600 and 200 MHz over a total length of 18 km. Radar data were acquired by repeatedly flying an L-band SAR along an oval racetrack at an altitude of about 1300 m over the glacier, such that two data stacks from opposite views are obtained. Data from all passes were coherently combined to achieve 3-D resolution capabilities, resulting in the generation of 3-D tomographic SAR (TomoSAR) cubes, where each voxel represents L-band radar reflectivity from a particular location in the 3-D space at a spatial resolution on the order of meters. TomoSAR cubes were finally corrected to account for wave propagation velocity into the ice, which was a necessary step to associate the observed features with their geometrical location, hence enabling a direct comparison to GPR data. The TomoSAR cubes show the complexity of the glacier subsurface scattering. Most areas are characterized by surface scattering in proximity of the ice surface, plus a complex pattern of in-depth volumetric scattering beneath and scattering at the ice/bedrock interface. Various subsurface features observed in GPR transects at 200 MHz clearly showed up in TomoSAR sections as well, particularly firn bodies, crevasses, layer transitions, and bedrock reflection down to 50 m below the ice surface.