Magnetic radiation shielding systems analysis. superconducting coil technology

Shielding effectiveness and system mass of different magnetic field configurations - Electric properties and magnetic behavior of superconducting coils of niobium-zirconium allo

Decreasing Cocaine Use with Repetitive Transcranial Magnetic Stimulation

Background: Dependence on cocaine causes significant functional impairment and morbidity in users and is extremely prevalent in the U.S. Unlike other abused substances, there is currently no effective standard of treatment to decrease cocaine cravings and prevent relapse. This systematic review assesses whether recent research shows that repetitive transcranial magnetic stimulation (rTMS) is an effective treatment to decrease cocaine use. Methods: An exhaustive search of the medical literature databases was performed using Medline-Ovid, CINAHL, and Web of Science with the search words “cocaine” and “transcranial magnetic stimulation”. The studies reviewed were chosen based on inclusion and exclusion criteria and were assessed for quality using the GRADE criteria. Results: There have only been two studies performed on rTMS’s effects on cocaine use specifically, which were both included in this review. Both studies showed evidence that rTMS decreases cocaine use. One study showed a significant increase in abstinence during, and up to 6 months after rTMS treatment and a significant decrease in cravings as a secondary outcome. The second study did not show a significant decrease in cocaine use for the rTMS group until an exploratory analysis was done. The quality of both studies was low to moderate based on the GRADE criteria. Conclusion: Despite the small number of studies assessing rTMS’s effectiveness on decreasing cocaine use and their low to moderate quality of evidence based on the GRADE criteria, the 2 studies reviewed here show promising evidence that rTMS can successfully decrease cocaine use. Trials with a larger sample size and higher attrition rate are required to more clearly show whether rTMS has a positive effect on decreasing cocaine use. Despite these limitations, since effective treatments are not currently available, the risk of rTMS treatment is low, and the cost of continued cocaine dependence is extremely high, rTMS treatment should be considered for patients trying to abstain from cocaine use

Advanced superconducting magnets investigation

Mathematical models for steady state behavior of composite superconductors and experimental verification using magnet coi

Plasma Dynamics

Contains research objectives and reports on two research projects

Results of a Parametric Study on 10,000 lb. and 50,000 lb. Permanent Magnetic Actuators

The purpose of this study was to generate design data and complete dynamic performance estimates for a high performance permanent magnet actuator. The basic configuration selected for analysis is an axisymmetric Nd-B-Fe permanent magnet actuator capable of providing force in one direction along its major axis. The actuator consisted of two main axisymmetric components separated by an air gap. The design was optimized for each value of force, gap and magnetic field to yield minimum weight and maximum lift to weight ratio. The basic conclusion is that, within parameters considered, the 10,000 lb. and 50,000 lb. actuators are lightweight and compact. As expected for most permanent magnet devices, the smaller ones have higher lift to eight ratios

Plasma Dynamics

Contains reports on four research projects

A 2 Tesla Full Scale High Performance Periodic Permanent Magnet Model for Attractive (228 KN) and repulsive Maglev

Two 214.5 cm. long high performance periodic (26 cm period) permanent magnet half-assemblies were designed and constructed for use as a wiggler using Nd-B-Fe and vanadium permendur as hard and soft magnetic materials by Field Effects, a division of Intermagnetics General Corporation. Placing these assemblies in a supporting structure with a 2.1 cm pole to pole separation resulted in a periodic field with a maximum value of 2.04 T. This is believed to be the highest field ever achieved by this type of device. The attractive force between the two 602 kg magnet assemblies is 228 kN, providing enough force for suspension of a 45,500 kg vehicle. If used in an attractive maglev system with an appropriate flat iron rail, one assembly will generate the same force with a gap of 1.05 cm leading to a lift to weight ratio of 38.6, not including the vehicle attachment structure. This permanent magnet compares well with superconducting systems which have lift to weight ratios in the range of 5 to 10. This paper describes the magnet assemblies and their measured magnetic performance. The measured magnetic field and resulting attractive magnetic force have a negative spring characteristic. Appropriate control coils are necessary to provide stable operation. The estimated performance of the assemblies in a stable repulsive mode, with eddy currents in a conducting guideway, is also discussed

Minimax Current Density Coil Design

'Coil design' is an inverse problem in which arrangements of wire are designed to generate a prescribed magnetic field when energized with electric current. The design of gradient and shim coils for magnetic resonance imaging (MRI) are important examples of coil design. The magnetic fields that these coils generate are usually required to be both strong and accurate. Other electromagnetic properties of the coils, such as inductance, may be considered in the design process, which becomes an optimization problem. The maximum current density is additionally optimized in this work and the resultant coils are investigated for performance and practicality. Coils with minimax current density were found to exhibit maximally spread wires and may help disperse localized regions of Joule heating. They also produce the highest possible magnetic field strength per unit current for any given surface and wire size. Three different flavours of boundary element method that employ different basis functions (triangular elements with uniform current, cylindrical elements with sinusoidal current and conic section elements with sinusoidal-uniform current) were used with this approach to illustrate its generality.Comment: 24 pages, 6 figures, 2 tables. To appear in Journal of Physics D: Applied Physic

Plasma Dynamics

Contains reports on three research projects.United States Atomic Energy Commission (Contract AT(30-1)-1842)United States Air Force, Air Force Cambridge Research Center, Air Research and Development Command (Contract AF19(604)-4551