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At least 775 records · Page 43

An inductively powered telemetry system for temperature, EKG, and activity monitoring

An implant telemetry system for the simultaneous monitoring of temperature, activity, and EKG from small animals, such as rats, has recently been designed with the novel feature that instead of a battery the system is energized by an inductive field. A 250 kHz resonant coil surrounds the cage (30 x 30 x 20 cm) and provides the approximately 100 microwatt of power required to operate the implant transmitter while allowing the animal unrestrained movement in the cage. The implant can also be battery operated if desired. RF transmission is in the 8-10 MHz band, which allows the use of a simple, essentially single IC chip, receiver.

Fryer, T. B.↗

Beam builder for space fabrication

Construction of a beam builder for producing triangular truss aluminum beams for use on large space structures is described. The machine will fabricate 0.04 cm thick 2024-T3 aluminum alloy into beams weighing 1.265 kg-m with side braces spot-welded to end caps to fabricate a triangular truss configuration up to 305 m long. The design characteristics, the electrical subsystems, the power requirements of the spot welding equipment, and the computer system for coordinating the motion of the Yoder rolling mills for forming caps from aluminum coils are described. Spot welding was compared with ultrasonic welding, stapling, wire stitching, riveting, grommets, stamp-lok, and pierce and fold joining methods with respect to ease of operation, safety, practicality, and ease of energy consumption. The beam builder will be evaluated to identify design requirements which can be utilized for the space flight version of its concept.

Ehl, J. H.↗

A search for geographic control on the occurrence of magnetospheric ELF emissions

Search coil magnetometer data obtained in the magnetosphere on Ogo 5 and Ogo 6 were studied for evidence of man-induced stimulation of the two dominant electromagnetic emissions, chorus and plasmaspheric hiss. Variability of chorus with geographic longitude and enhancements, onsets, and quantum jumps in chorus emissions at frequencies related to harmonics of the earth's transmission lines are discussed. The enhancement of weak emissions in the 340-360 deg dipole longitude region during quiet geomagnetic conditions is present only when ELF hiss is weak, and will not contribute to the non-adiabatic dynamics of radiation belt electrons. It is concluded that the data analyzed is consistent with a predominantly natural origin for chorus and plasmaspheric hiss, and that triggered waves do not play a major role in the non-adiabatic dynamics of geomagnetically trapped electrons.

Tsurutani, B. T.↗

Differential capacitance sensor as position detector for a magnetic suspension densimeter

In the present work, which consists of adapting a magnetic suspension densimeter for use at pressures up to 350 bars, a differential capacitance sensor is developed for use in the servosystem of a magnetic suspension densimeter for detecting the position of a magnetic buoy. This type of sensor has not been used previously in magnetic suspension densimeters. Its design, performance, and advantages are outlined. A cutaway drawing and a schematic diagram of the capacitance sensor and magnetic buoy are presented and described. The concentric-disk design of the sensor capacitor plates and the high degree of symmetry which results from the printed circuit fabrication approach minimize the sensor sensitivity to lateral displacement of the buoy and to the dielectric constant of the surrounding medium. A high-power microscope is necessary to monitor the position of the buoy relative to the support coil.

Frederick, N. V.↗

Torque control for electric motors

Method for adjusting electric-motor torque output to accomodate various loads utilizes phase-lock loop to control relay connected to starting circuit. As load is imposed, motor slows down, and phase lock is lost. Phase-lock signal triggers relay to power starting coil and generate additional torque. Once phase lock is recoverd, relay restores starting circuit to its normal operating mode.

Bernard, C. A.↗

A linear magnetic motor and generator

In linear magnetic motor and generator suitable for remote and hostile environments, magnetic forces drive reciprocating shaft along its axis. Actuator shaft is located in center of cylindrical body and may be supported by either contacting or noncontacting bearings. When device operates as bidirectional motor, drive coil selectively adds and subtracts magnetic flux to and from flux paths, producing forces that drive actuator along axis. When actuator is driven by external reciprocating engine, device becomes ac generator.

Studer, P. A.↗

Shrinking plastic tubing and nonstandard diameters

Process allows larger-than-normal postshrink diameters without splitting. Tetrafluoroethylene tubing on mandrel is supported within hot steel pipe by several small diameter coil sections. Rising temperature of mandrel is measured via thermocouple so assembly can be removed without overshrinking (and splitting) of tubing.

Ruiz, W. V.↗

Costs and description of a solar-energy system--Austin, Texas

Heating and cooling system uses Fresnel lens concentrating collectors. Major system components are 36 collectors, 1,500 gallon thermal storage tank, absorption cooler, cooling tower, heating coil, pumps, heat exchanger, and backup heating and air conditioning. Final report includes detailed breakdown of component and installation costs for seven project subsystems.

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Eliminating gaps in split rings

Simple installation method allows thinner, lighter tether rings than conventional procedures, saving expensive materials. Installer inverts ring with pliers before it is slid over cable, then returns it to its original position after installation. Ring is in correct orientation, and coils are tightly compressed for high reliability fastening.

Gould, R. W.↗

Leading edge vortex-flap experiments on a 74 deg delta wing

Exploratory wind tunnel tests are reported on a 74 deg. delta wing model. The potential of a vortex flap concept in reducing the subsonic lift dependent drag of highly swept, slender wings is examined. The suction effect of coiled vortices generated through controlled separation over leading edge flap surfaces to produce a thrust component is discussed. A series of vortex-flap configurations were investigated to explore the effect of some primary geometric variables.

Rao, D. M.↗

Induction powered biological radiosonde

An induction powered implanted monitor for epidurally measuring intracranial pressure and telemetering the pressure information to a remote readout is disclosed. The monitor utilizes an inductance-capacitance (L-C) oscillator in which the C comprises a variable capacitance transducer, one electrode of which is a small stiff pressure responsive diaphragm. The oscillator is isolated from a transmitting tank circuit by a buffer circuit and all electric components in the implanted unit except an input and an output coil are shielded by a metal housing.

Fryer, T. B.↗

Space fabrication: Graphite composite truss welding and cap forming subsystems

An automated beam builder for the fabrication of space structures is described. The beam builder forms a triangular truss 1.3 meters on a side. Flat strips of preconsolidated graphite fiber fabric in a polysulfone matrix are coiled in a storage canister. Heaters raise the material to forming temperature then the structural cap section is formed by a series of rollers. After cooling, cross members and diagonal tension cords are ultrasonically welded in place to complete the truss. The stability of fabricated structures and composite materials is also examined.

Jenkins, L. M.↗

Installation guidelines for solar heating system, single-family residence at New Castle, Pennsylvania

The solar heating system installer guidelines are presented for each subsystem. This single family residential heating system is a solar-assisted, hydronic-to-warm-air system with solar-assisted domestic water heating. It is composed of the following major components: (1) liquid cooled flat plate collectors; (2) water storage tank; (3) passive solar-fired domestic water preheater; (4) electric hot water heater; (5) heat pump with electric backup; (6) solar hot water coil unit; (7) tube-and-shell heat exchanger, three pumps, and associated pipes and valving in an energy transport module; (8) control system; and (9) air-cooled heat purge unit. Information is provided on the operating procedures, controls, caution requirements, and routine and schedule maintenance in the form of written descriptions, schematics, detail drawings, pictures, and manufacturer's component data.

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Velocity servo for continuous scan Fourier interference spectrometer

A velocity servo for continuous scan Fourier interference spectrometer of the double pass retroreflector type having two cat's eye retroreflectors is described. The servo uses an open loop, lead screw drive system for one retroreflector with compensation for any variations in speed of drive of the lead screw provided by sensing any variation in the rate of reference laser fringes, and producing an error signal from such variation used to compensate by energizing a moving coil actuator for the other retroreflector optical path, and energizing (through a highpass filter) piezoelectric actuators for the secondary mirrors of the retroreflectors.

Schindler, R. A.↗

Superconducting bearings for application in cryogenic experiments in space

Linear superconducting magnetic bearings suitable for use in a proposed orbital equivalence principle experiment and for general application in space were developed and tested. Current flows in opposite directions in adjacent superconducting wires arranged parallel to the axis of a cylinder. This configuration provides maximum stiffness radially while allowing the test mass to move freely along the cylinder axis. In a space application, the wires are extended to cover the entire perimeter of the cylinder: for the earth-based tests it was desirable to use only the bottom half. Control of the axial position of the test mass is by small control coils which may be positioned inside or outside the main bearing. The design is suitable for application to other geometries where maximum stiffness is desired. A working model scaled to operate in a 1-g environment was perfected approximate solutions for the bearings were developed. A superconducting transformer method of charging the magnets for the bearing, and a position detector based on a SQUID magnetometer and associated superconducting circuit were also investigated.

Everitt, C. W. F.↗

Installation guidelines for solar heating system, single-family residence at William OBrien State Park, Stillwater, Minnesota

Installation procedures for the single family residential solar heating system at the William O'Brien State Park, Stillwater, Minnesota, are presented. The system is a solar-assisted, hydronic-to-warm-air system with solar-assisted domestic water heating. It is composed of the following major components: liquid cooled flat plate collectors; water storage tank; passive solar-fired domestic water preheater; electric hot water heater; heat pump with electric backup; solar hot water coil unit; tube-and-shell heat exchanger, three pumps, and associated pipes and valving in an energy transport module; control system; and air-cooled heat purge unit. Installer guidelines are provided for each subsystem and includes testing and filling the system. Information is also given on the operating procedures, controls, caution requirements and routine and schedule maintenance.

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Two-dimensional representations of axisymmetric fields for computer calculations

An accurate representation of axisymmetric fields has been devised by extending the method of ideal current loops to off-axis fields. It is assumed that the data to be simulated are available through measurements or through a solution of a boundary value problem. The method provides an algebraic expression for the fields throughout a two-dimensional region of interest and eliminates the need for the axial expansion formula in approximating off-axis fields. The use of Gaussian and other functions as alternatives to the coil function is proposed. Examples of the technique in simulating a periodic permanent magnet (PPM) focusing field are presented and compared with a Fourier analysis of the problem.

Stankiewicz, N.↗

Space applications of superconductivity - High field magnets

The paper discusses developments in superconducting magnets and their applications in space technology. Superconducting magnets are characterized by high fields (to 15T and higher) and high current densities combined with low mass and small size. The superconducting materials and coil design are being improved and new high-strength composites are being used for magnet structural components. Such problems as maintaining low cooling temperatures (near 4 K) for long periods of time and degradation of existing high-field superconductors at low strain levels can be remedied by research and engineering. Some of the proposed space applications of superconducting magnets include: cosmic ray analysis with magnetic spectrometers, energy storage and conversion, energy generation by magnetohydrodynamic and thermonuclear fusion techniques, and propulsion. Several operational superconducting magnet systems are detailed.

Fickett, F. R.↗