Large gap magnetic suspension system

The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system

Magnetic suspension and balance system advanced study

An improved compact design for a superconducting magnetic suspension and balance system for an 8 ft. x 8 ft. transonic wind tunnel is developed. The original design of an MSBS in NASA Cr-3802 utilized 14 external superconductive coils and a superconductive solenoid in the airplane test model suspended in a wind tunnel. The improvements are in the following areas: test model solenoid options, dynamic force limits on the model, magnet cooling options, structure and cryogenic designs, power supply specifications, and cost and performance evaluations. The improvements are: MSBS cost reduction of 28%, weight; reduction of 43%, magnet system ampere-meter reduction of 38%, helium liquifier capacity reduction by 33%, magnet system stored energy reduction by 55%, AC loss to liquid helium reduced by 76%, system power supply reduced by 68%, test coil pole strength increased by 19%, wing magnetization increased by 40%, and control frequency limit increased by 200% from 10 Hz to 30 Hz. The improvements are due to: magnetic holmium coil forms in the test model, better rare earth permanent magnets in the wings, fiberglass-epoxy structure replacing stainless steel, better coil configuration, and new saddle roll coil design

Repulsive force support system feasibility study

A new concept in magnetic levitation and control is introduced for levitation above a plane. A set of five vertical solenoid magnets mounted flush below the plane supports and controls the model in five degrees of freedom. The compact system of levitation coils is contained in a space 2.4 m (96 in) diameter by 1 m (40 in) deep with the top of the levitation system 0.9 m (36 in) below the center line of the suspended model. The levitated model has a permanent magnet core held in position by the five parallel superconductive solenoids symmetrically located in a circle. The control and positioning system continuously corrects for model position in five dimensions using computer current pulses superimposed on the levitation coil base currents. The conceptual designs include: superconductive and Nd-Fe-B permanent magnet model cores and levitation solenoids of either superconductive, cryoresistive, or room temperature windings

Magnetic suspension and balance system advanced study, 1989 design

The objectives are to experimentally confirm several advanced design concepts on the Magnetic Suspension and Balance Systems (MSBS). The advanced design concepts were identified as potential improvements by Madison Magnetics, Inc. (MMI) during 1984 and 1985 studies of an MSBS utilizing 14 external superconductive coils and a superconductive solenoid in an airplane test model suspended in a wind tunnel. This study confirmed several advanced design concepts on magnetic suspension and balance systems. The 1989 MSBS redesign is based on the results of these experiments. Savings of up to 30 percent in supporting magnet ampere meters and 50 percent in energy stored over the 1985 design were achieved

Magnetic suspension and balance system study

A compact design for a superconducting magnetic suspension and balance system is developed for a 8 ft. x 8 ft. transonic wind tunnel. The main features of the design are: a compact superconducting solenoid in the suspended airplane model; permanent magnet wings; one common liquid helium dewar for all superconducting coils; efficient new race track coils for roll torques; use of established 11 kA cryostable AC conductor; acceptable AC losses during 10 Hz control even with all steel structure; and a 560 liter/hour helium liquefier. Considerable design simplicity, reduced magnet weights, and reduced heat leak results from using one common dewar which eliminates most heavy steel structure between coils and the suspended model. Operational availability is thought to approach 100% for such magnet systems. The weight and cost of the magnet system is approximately one-third that of previous less compact designs

Design of a Superconducting Magnetic Suspension System for a Liquid Helium Flow Experiment

We discuss a preliminary design for a superconducting magnetic suspension system for measurement of drag on rotationally symmetric bodies in liquid helium. Superconducting materials are a natural choice for liquid helium studies, since temperatures are well below most critical temperatures, so that the resulting heat load is negligible. Also, due to its diamagnetic properties, a superconducting model (for example made or coated with Nb) is inherently stable against disturbances. Issues which we consider include model placement during initial cool-down, maintaining placement during anticipated drag and lift forces, and force measurement. This later can be achieved by a passive technique, where the body is allowed to deflect under the influence of drag from its neutral position. The resulting shift in flux is detected via a superconducting pickup coil. The pickup coil may be connected either to a SQUID, or a secondary loop wound around a Hall probe. Both options are discussed. The objective of this work is to gain a better understanding of the nature of turbulent fields in normal and superfluid helium for potential application to problems in classical high Reynolds number turbulence

Superconducting energy storage magnet

A superconducting magnet is formed having composite conductors arrayed in coils having turns which lie on a surface defining substantially a frustum of a cone. The conical angle with respect to the central axis is preferably selected such that the magnetic pressure on the coil at the widest portion of the cone is substantially zero. The magnet structure is adapted for use as an energy storage magnet mounted in an earthen trench or tunnel where the strength the surrounding soil is lower at the top of the trench or tunnel than at the bottom. The composite conductor may be formed having a ripple shape to minimize stresses during charge up and discharge and has a shape for each ripple selected such that the conductor undergoes a minimum amount of bending during the charge and discharge cycle. By minimizing bending, the working of the normal conductor in the composite conductor is minimized, thereby reducing the increase in resistance of the normal conductor that occurs over time as the conductor undergoes bending during numerous charge and discharge cycles

Conceptual design of a scalable multi-kton superconducting magnetized liquid Argon TPC

We discuss the possibility of new generation neutrino and astroparticle physics experiments exploiting a superconducting magnetized liquid Argon Time Projection Chamber (LAr TPC). The possibility to complement the features of the LAr TPC with those provided by a magnetic field has been considered in the past and has been shown to open new physics opportunities, in particular in the context of a neutrino factory. The experimental operation of a magnetized 10 lt LAr TPC prototype has been recently demonstrated. From basic proof of principle, the main challenge to be addressed is the possibility to magnetize a very large volume of Argon, corresponding to 10 kton or more, for future neutrino physics applications. In this paper we present one such conceptual design.Comment: 4 pages, 1 figure, invited talk at 7th International Workshop on Neutrino Factories and Superbeams (NUFACT05), LNF, Frascati (Rome

Khat (Catha edulis Forsk) and its effect on anti-malarial chemotherapy

Millions of Yemenis and East Africans habitually chew daily the fresh leaves and twigs of Catha edulis commonly known as khat; it produces a stimulating amphetamine-like effect. Most people believe that khat leaves relieve fatigue and reduce body temperature; therefore it is a common practice to chew khat during sickness and during treatment. The effect of khat chewing on the bioavailability of certain antibiotics has been studied; the outcome of these studies showed that khat chewing significantly reduced the bioavailability of the antibiotics, however, khat and its effect on anti-malarial drugs has not been studied. The aim of this study was to evaluate the effect of khat on antimalarial chemotherapy and to explore possible pharmacokinetic interactions between chloroquine (CQ) and khat duri!1g co-administration in healthy adult Yemeni volunteers. Furthermore, we wanted to determine the effect of khat on CQ concentration, parasitaemia and parasite clearance in Plasmodium falciparum infected patients. In addition, anti-malarial activity was tested in vitro against CQ sensitive-resistant strains. In a two-phase cross-over study, 15 healthy adult male volunteers were given a single dose of 600 mg of CQ with and without khat. Plasma concentrations ofCQ were determined during a 24 h period following drug administration on both occasions. CQ plasma concentrations were determined by a validated HPLC-UV method. Pharmacokinetic parameters ofCQ were calculated using compartmental analysis. In the two periods of treatment, the mean (SD) peak plasma concentrations (Cmax) were 415 (103) nglml (CQ with khat) and 508 (106) ng/ml (CQ alone). The total areas under the curve (ACUO-24) were 2108 (682) ng/h/ml (CQ with khat) and 2797 (845) ng/h Iml (CQ alone). The time taken to reach Cmax (Tmax) was 3.8 (0.41) hand 3.6 (0.51) h. and elimination half-life (tv,) was 7.7 (2.10) hand 7.5 (2.77) h respectively. Statistically significant differences were observed for both (Cmax) (p < .001) and (ACUO-24) (p< .003) of CQ when comparing values with or without khat. These results demonstrat~ a pharmacokinetic interaction between CQ and khat and suggest that the observed interaction may be clinically significant, although the CQ levels were above the therapeutic level for P.falciparum