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A study was conducted on the performance of a four pole high temperature superconducting synchronous motor with racetrack field windings. Tests were conducted at the 20 K nominal operating temperature and at 4.2 K and 77 K. The motor generated 1500 W nominal power at 1500 rpm and a 205 A excitation current. At 77 K and 4.2 K, gradual transition between the superconducting and normal state was observed.

A three pole superconducting wiggler magnet has been constructed to be used as a light source in a 1.5 GeV electron storage ring at the University of Lurid, Sweden. The main design principles have been reported in [1] and [2]. With a central flux density [B.sub.0] of 6 T, the high field wiggler will produce X-rays with a critical wavelength of 138 [Angstrom]. During construction three different kind of racetrack type windings were made. The comparison concerning the magnet stability between the different coil concepts has been evaluated with different supporting structures and magnet ramping rates. The main performance of the magnet system and the influence of training are discussed. Quench analysis and the cryogenic facility are also included in the discussion.

In order to achieve a gearless construction of the wind energy conversion system (WECS) a low-speed, i.e. multi-pole, generator is required. This paper examines an axial-field permanent-magnet synchronous wind power generator (PMWG) mainly from the magnetic viewpoint. Both mechanical and electromagnetic designs are described as well as some primary test results concerning the model generators having nominal power of 5 and 10 kW.

A four-pole rotating armature type synchronous machine with HTS stationary field windings has been constructed. The Bi-2223/Ag racetrack coils are made by American Superconductor Co. An overall current density of 4,700 A/[cm.sup.2] has been obtained at the operating temperature of 20 K in a 0.7 T field. At 20 K silver and Bi-2223 have much higher heat capacities compared to 4 K. This combined with a wide margin between the operating and critical temperature improves the stability of the magnet system. In addition the ratio of the stored energy of the coils and the required cooling power reaches the maximum at the temperature range of 20-40 K. The cryostat has also been designed in order to meet the requirements of liquid helium. The armature is a three-phase air gap copper winding. The description of the machine and the design based on the 3D field analysis in a steady state operation will be presented.

The training performance and quenching characteristics of a wiggler magnet were quantified. The observed values were then compared to numerical estimates to confirm the design's validity. The superconducting magnet was developed and tested by Finland's Tampere University of Technology for Sweden's University of Lund which has a facility for a 1.5-GeV synchrotron radiation source.

The purpose of this study was to describe changes in hearing, using the permanent threshold shift metric, among United States Air Force servicemembers, including active duty, Reserve and Air National Guard components, for demographics, job categories, and career fields. In the United States Air Force, only servicemembers who are occupationally exposed routinely to hazardous noise are monitored. Audiogram records and demographic variables were analyzed for servicemembers from 2005-2011 using data from the Department of Defense system that captures occupational hearing tests worldwide. Results suggest that occupational hearing loss was larger in males than females, in officers than enlisted populations, and in Reserve and Air National Guard than in active duty. Compared to similar civilian career fields, active duty has lower prevalence rates for occupational hearing loss overall, although Reserve and Air National Guard prevalence rates were more similar to the civilian reported rates. The proportion of personnel with permanent threshold shifts varied between 4.6-16.7% within active duty career fields, which includes 76% of the population for study timeframe. Permanent threshold shift was larger in small job categories, and in jobs that are not considered exposed to hazardous noise routinely which is comparative with results from civilian data analysis of occupational hearing loss. Further investigation into testing practices for Air Force specific groups, use of the system for nonoccupational hearing testing, and challenges to follow-up compliance is warranted. Increased surveillance procedures for occupational hearing loss are needed to address concerns on the prevalence of servicemember hearing loss, the role of recreational and lifestyle factors to contribute the high reported hearing loss prevalence of veterans compared to nonveterans.