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At least 1,441 records · Page 80

All sources NASA NTRS DOE OSTI

NASA NTRS1974

Radiation hardening of MOS devices by boron

A technique is described for radiation hardening of MOS devices and specifically for stabilizing the gate threshold potential at room temperature of a radiation subjected MOS field-effect device with a semiconductor substrate, an insulating layer of oxide on the substrate, and a gate electrode disposed on the insulating layer. The boron is introduced within a layer of the oxide of about 100 A-300 A thickness immediately adjacent the semiconductor-insulator interface. The concentration of boron in the oxide layer is preferably maintained on the order of 10 to the 18th power atoms/cu cm. The technique serves to reduce and substantially annihilate radiation induced positive gate charge accumulations.

Danchenko, V.↗

NASA NTRS1974

Device for recording the 20 Hz - 200 KHz sound frequency spectrum using teletransmission

The device described consists of two distinct parts: (1) The sound pickup system consisting of the wide-frequency band condenser microphone which contains in the same assembly the frequency-modulated oscillator and the output stage. Being transistorized and small, this system can be easily moved, so that sounds can be picked up even in places that are difficult to reach with larger devices. (2) The receiving and recording part is separate and can be at a great distance from the sound pickup system. This part contains a 72 MHz input stage, a frequency changer that gives an intermediate frequency of 30 MHz and a multichannel analyzer coupled to an oscilloscope and a recorder.

Baciu, I.↗

NASA NTRS1974

Device for monitoring a change in mass in varying gravimetric environments

A remotely operable device for detecting changes as they occur in the mass of a selected specimen is described. The device is characterized by a balance beam including at one end a support for receiving a specimen having a changing mass and suspension means, including a flexure, supporting the beam near its center of gravity for pivotal movement proportional to changes occurring in the mass of the specimen. Strain gages coupled with the flexure provide a read-out indicative of the pivotal movement imparted to the beam.

Valinsky, J. P.↗

NASA NTRS1974

Laboratory demonstration model: Active cleaning technique device

The technique which utilizes exposure to a plasma to remove contaminants from a surface was incorporated into a laboratory model which demonstrates active cleaning by both plasma cleaning and ion sputtering modes of operation. The development phase is reported and includes discussion of the plasma tube configuration, device design, and performance tests. A general description of the active cleaning device is provided which includes information on the main power/plasma discharge sensors, and the power, gas supply, and ion accelerator systems. Development of the active cleaning species at high vacuum conditions is described and results indicate that plasma cleaning occurs in the region of a visible plume which extends from the end of the plasma tube. Recommendations are made for research to determine the plasma cleaning mechanism and the plasma species responsible for the cleaning, as well limitations on the type of contaminants that can be removed.

Shannon, R. L.↗

NASA NTRS1974

Fluid technology (selected components, devices, and systems): A compilation

Developments in fluid technology and hydraulic equipment are presented. The subjects considered are: (1) the use of fluids in the operation of switches, amplifiers, and servo devices, (2) devices and data for laboratory use in the study of fluid dynamics, and (3) the use of fluids as controls and certain methods of controlling fluids.

Source record↗

NASA NTRS1973

Diagnostic device for monitoring the technical condition of mechanical assemblies

An automatic diagnostic device for monitoring the condition of tractor transmission gears is described. The structural noise spectrum of the gearshift box and rear axle of the tractor were analyzed in a digital computer, by an algorithm based on the multiple correlation method. The optimum assembly of operating frequencies, by use of which the errors in measurement were minimized, was selected from the entire frequency spectrum. Selected frequencies are necessary for choosing the measurement range of the diagnostic device. It turned out that, to obtain a relative error of no more than 2%, it was sufficient to use two filters, vibrating only at the frequencies carrying the maximum data of the mechanical parameter being investigated. The measurement system consists of frequency-selection filters, amplifiers and quadratic detectors, at the outlets of which constant voltages are created, which are proportional to the signal level at the frequencies selected.

Osovskiy, V. I.↗

NASA NTRS1973

Measurement of irregularities in angular velocities of rotating assemblies in memory devices on magnetic carriers

Problems in measurement of irregularities in angular velocity of rotating assemblies in memory devices with rigid and flexible magnetic data carriers are discussed. A device and method for determination of change in angular velocities in various frequency and rotation rate ranges are examined. A schematic diagram of a photoelectric sensor for recording the signal pulses is provided. Mathematical models are developed to show the amount of error which can result from misalignment of the test equipment.

Virakas, G. I.↗

NASA NTRS1975

Motor-driven rack-positioning device

Ramped clutch plate prevents damage to gear traing and provides ample linear motion for actuation of microswitch. Operation of device is not affected by number of revolutions which pinion shaft must make to produce required translations. Since ramps in spur gear are conical, device will actuate identically at each mechanical stop.

Crissey, M. E.↗

NASA NTRS1975

Angular device for optical filters

Device provides a means for precise angular adjustment of optical filters in Raman calibration detector units. Device prevents stray light from entering system and has the capability of repeated alignments to predetermined angles.

Overbay, L. W.↗

NASA NTRS1974

Determining iconometric parameters of imaging devices using a wide-angle collimator

The problem of determining the iconometric parameters of the imaging device can be solved if the camera being calibrated is used to obtain the image of a group of reference points, the directions to which are known. In order to specify the imaging device coordinate system, it is sufficient in principle to obtain on the picture the images of three reference points which do not lie on a single straight line. Many more such points are required in order to determine the distortion corrections, and they must be distributed uniformly over the entire field of view of the camera being calibrated. Experimental studies were made using this technique to calibrate photographic and phototelevision systems. Evaluation of the results of these experiments permits recommending collimators for calibrating television and phototelevision imaging systems, and also short-focus small-format photographic cameras.

Ziman, Y. L.↗

NASA NTRS1974

Aerodynamic drag reduction tests on a full-scale tractor-trailer combination with several add-on devices

Aerodynamic drag tests were performed on a conventional cab-over-engine tractor with a 45-foot trailer and five commercially available or potentially available add-on devices using the coast-down method. The tests ranged in velocity from approximately 30 miles per hour to 65 miles per hour and included some flow visualization. A smooth, level runway at Edwards Air Force Base was used for the tests, and deceleration measurements were taken with both accelerometers and stopwatches. An evaluation of the drag reduction results obtained with each of the five add-on devices is presented.

Montoya, L. C.↗

NASA NTRS1975

Anti-gravity device

An educational toy useful in demonstrating fundamental concepts regarding the laws of gravity is described. The device comprises a sphere 10 of radius r resting on top of sphere 12 of radius R. The center of gravity of sphere 10 is displaced from its geometrical center by distance D. The dimensions are so related that D((R+r)/r) is greater than r. With the center of gravity of sphere 10 lying on a vertical line, the device is in equilibrium. When sphere 10 is rolled on the surface of sphere 12 it will return to its equilibrium position upon release. This creates an illusion that sphere 10 is defying the laws of gravity. In reality, due to the above noted relationship of D, R, and r, the center of gravity of sphere 10 rises from its equilibrium position as it rolls a short distance up or down the surface of sphere 12.

Palsingh, S.↗

NASA NTRS1974

Liquid rocket engine combustion stabilization devices

Combustion instability, which results from a coupling of the combustion process and the fluid dynamics of the engine system, was investigated. The design of devices which reduce coupling (combustion chamber baffles) and devices which increase damping (acoustic absorbers) are described. Included in the discussion are design criteria and recommended practices, structural and mechanical design, thermal control, baffle geometry, baffle/engine interactions, acoustic damping analysis, and absorber configurations.

Source record↗

NASA NTRS1975

Electrical and electronic devices and components: A compilation

Components and techniques which may be useful in the electronics industry are described. Topics discussed include transducer technology, printed-circuit technology, solid state devices, MOS transistors, Gunn device, microwave antennas, and position indicators.

Source record↗

NASA NTRS1975

Boron Arsenide and Boron Phosphide for High Temperature and Luminescent Devices

The crystal growth of boron arsenide and boron phosphide in the form of bulk crystals and epitaxial layers on suitable substrates is discussed. The physical, chemical, and electrical properties of the crystals and epitaxial layers are examined. Bulk crystals of boron arsenide were prepared by the chemical transport technique, and their carrier concentration and Hall mobility were measured. The growth of boron arsenide crystals from high temperature solutions was attempted without success. Bulk crystals of boron phosphide were also prepared by chemical transport and solution growth techniques. Techniques required for the fabrication of boron phosphide devices such as junction shaping, diffusion, and contact formation were investigated. Alloying techniques were developed for the formation of low-resistance ohmic contacts to boron phosphide. Four types of boron phosphide devices were fabricated: (1) metal-insulator-boron phosphide structures, (2) Schottky barriers; (3) boron phosphide-silicon carbide heterojunctions; and (4) p-n homojunctions. Easily visible red electroluminescence was observed from both epitaxial and solution grown p-n junctions.

Chu, T. L.↗

NASA NTRS1975

Development of a laboratory demonstration model active cleaning device

A laboratory demonstration model of a device for removing contaminant films from optical surfaces in space was developed. The development of a plasma tube, which would produce the desired cleaning effects under high vacuum conditions, represented the major problem in the program. This plasma tube development is discussed, and the resulting laboratory demonstration-model device is described.

Shannon, R. L.↗

NASA NTRS1975

Mechanical test in-situ fracture device for Auger electron spectroscopy

An in-situ fracture device for Auger spectroscopy was described. The device is designed to handle small tensile specimens or small double cantilever beam specimens and is fully instrumented with load and displacement transducers so that quantitative stress-strain measurements can be made directly. Some initial test results for specimens made from 4130 and 1020 steel were presented.

Moorhead, R. D.↗

NASA NTRS1976

Heat transfer device

An improved heat transfer device particularly suited for use as an evaporator plate in a diffusion cloud chamber. The device is characterized by a pair of mutually spaced heat transfer plates, each being of a planar configuration, having a pair of opposed surfaces defining therebetween a heat pipe chamber. Within the heat pipe chamber, in contiguous relation with the pair of opposed surfaces, there is disposed a pair of heat pipe wicks supported in a mutually spaced relationship by a foraminous spacer of a planar configuration. A wick including a foraminous layer is contiguously related to the external surfaces of the heat transfer plates for uniformly wetting these surfaces.

Eaton, L. R.↗