Psychiatry’s Shocking New Tools
The cover story, “Psychiatry’s Shocking New Tools,” in the March 2006 IEEE Spectrum addresses the biomedical research into treating depression electromagnetically rather than through the use of drugs. The power supply for transcranial magnetic stimulation described in the article was designed and built by CEM staff members. In addition, a paper co-authored by K. Davey of CEM was highlighted. A copy of this paper can be found here. For further information, contact K.Davey.
Suppressing the Surface Field during Transcranial Magnetic Stimulation
Transcranial Magnetic Stimulation (TMS) commonly is used as both a diagnostic tool and as an alternative to electric shock therapy for the treatment of clinical depression. Among the clinical issues encountered in its use is the mitigation of accompanying pain. The objective becomes one of minimizing the induced surface field while still achieving the target field objective. Three techniques for realizing this end were discussed in a paper, “Suppressing the Surface Field during Transcranial Magnetic Stimulation,” by Kent R. Davey and Mark Riehl, that was published in the IEEE Transactions on Biomedical Engineering, vol. 53, no. 2, pp. 190-194, February 2006. These techniques are (1) placing a conducting shield over a portion of the central target region, (2) using supplementary coils of opposite polarity in tandem with the primary field, and (3) opening the core angle to distribute the field. Option (3) shows the greatest promise for reducing the ratio of the maximum surface field to induced target field. For further information, contact Kent R. Davey.
Core opened to 140 degrees, 3790 AT excitation at 5280 Hz. |
Challenges and Solutions for the Use of Flywheel Energy Storage in High Power Applications
CEM is currently developing and testing a 2 MW, 130 kWh flywheel energy storage system as a critical element of the Advanced Locomotive Propulsion System (ALPS) Program. The ALPS program is sponsored by the Federal Railroad Administration with the goal of demonstrating the feasibility of an advanced hybrid electric propulsion system for high speed passenger locomotives.
The ALPS energy storage system consists of a high speed energy storage flywheel, a 2 MW high speed induction motor/generator, and a high frequency bi-directional power converter. In the course of developing the energy storage system for this demanding mobile application, CEM identified and developed effective solutions for several critical technical issues which have challenged the use of high speed flywheels for high power energy storage applications. Although these issues were addressed for the more challenging mobile environment, they are also relevant to stationary applications. Technical challenges addressed by this effort include:
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Design, fabrication and assembly of large high speed composite energy storage flywheels
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Techniques to ensure safe, reliable operation of the flywheel while providing containment for rotor burst events
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Advanced active magnetic bearings and rotor dynamics
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Development of continuous duty, high speed, high power motor/generators for transferring energy to/from the energy storage flywheel
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High power, high frequency bi-directional power converters to interface the flywheel to a dc bus or utility grid
A paper describing the locomotive propulsion system and discussing the critical technical challenges presented by the flywheel energy storage system and the solutions developed by the CEM team, “Challenges and Solutions for the Use of Flywheel Energy Storage in High Power Applications,” by John Herbst, Matthew Caprio, Angelo Gattozzi, and Carl Graf, was presented at the Electrical Energy Storage Applications and Technologies Conference (EESAT 2005) in October 2005.
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