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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

A system for early warning of bearing failure

System for detecting incipient failure in ball bearings is described. Ultrasonic equipment detects bearing system resonance and provides warning signal through electronic circuitry. Detector can be used to evaluate performance of newly installed bearings. Schematic diagram is provided to show components.

Broderick, J. J.↗
NASA NTRS1972

Investigation of the performance characteristics of Doppler radar technique for aircraft collision hazard warning, phase 3

System studies, equipment simulation, hardware development and flight tests which were conducted during the development of aircraft collision hazard warning system are discussed. The system uses a cooperative, continuous wave Doppler radar principle with pseudo-random frequency modulation. The report presents a description of the system operation and deals at length with the use of pseudo-random coding techniques. In addition, the use of mathematical modeling and computer simulation to determine the alarm statistics and system saturation characteristics in terminal area traffic of variable density is discussed.

Source record↗
NASA NTRS1972

A digital simulation of message traffic for natural disaster warning communications satellite

Various types of weather communications are required to alert industries and the general public about the impending occurrence of tornados, hurricanes, snowstorms, floods, etc. A natural disaster warning satellite system has been proposed for meeting the communications requirements of the National Oceanic and Atmospheric Administration. Message traffic for a communications satellite was simulated with a digital computer in order to determine the number of communications channels to meet system requirements. Poisson inputs are used for arrivals and an exponential distribution is used for service.

Hein, G. F.↗
NASA NTRS1973

Brake wear warning device: A concept

Heat-insulated wire is introduced through brake shoe and partially into brake lining. Wire is connected to positive terminal and light bulb. When brakes wear to critical point, contact between wire and wheel drum grounds circuit and turns on warning light.

Hawkins, S. F.↗
NASA NTRS1972

Systems simulation for an airport trailing vortex warning system

The approach, development, and limited system studies associated with a system simulation for an Airport Trailing Vortex Warning System are documented. The usefulness is shown of a systems engineering approach to the problem of developing a system, as dictated by aircraft vortices, which will increase air-traffic flow in the takeoff/landing corridors of busy airports while maintaining the required safety factor for each operation. The simulation program has been developed in a modular form which permits new, more sophisticated component models, when they become available and are required, to be incorporated into the program with a minimum of program modifications. This report documents a limited system study that has been performed using this Total System Simulation Model. The resulting preliminary system requirements, conclusions, and recommendations are given.

Jeffreys, H. B.↗
NASA NTRS1972

Avoidance of Trailing Vortex Hazard by Airport Warning System

In an effort to improve airport traffic operation near jumbo jets, an airport trailing vortex warning system (ATVWS) was developed to predict trailing vortex turbulence. The ATVWS consists of a computer simulator which is compatible with a vortex sensor such as a laser Doppler velocimeter or an acoustic radar. A study of the traffic in one of the ten busiest airports, Atlanta Municipal Airport, provided information on traffic patterns of a statistical nature. With this information, airport traffic patterns can be studied and hazard statistics developed. Based on a careful study of this simulation model, requirements for the development and testing of an ATVWS can be accurately specified.

Rudland, R. S.↗
NASA NTRS1975

Fabrication and evaluation of polymeric early-warning fire-alarm devices

The electrical resistivities were investigated of some polymers known to be enhanced by the presence of certain gases. This was done to make a device capable of providing early warning to fire through its response with the gases produced in the early phases of combustion. Eight polymers were investigated: poly(phenyl acetylene), poly(p-aminophenyl acetylene), poly(p-nitrophenyl acetylene), poly(p-formamidophenyl acetylene), poly(ethynyl ferrocene), poly(ethynyl carborane), poly(ethynyl pyridine), and the polymer made from 1,2,3,6 tetramethyl pyridazine. A total of 40 usable thin-film sandwich devices and a total of 70 usable interdigitated-electrode lock-and-key devices were fabricated. The sandwich devices were used for measurements of contact linearity, polymer conductivity, and polymer dielectric constant. The lock-and-key devices were used to determine the response of the polymers to a spectrum of gases that included ammonia, carbon nonoxide, carbon dioxide, sulfur dioxide, ethylene, acrolein, water vapor, and normal laboratory air. Strongest responses were to water vapor, ammonia, and acrolein, and depending on the polymer, weaker responses to carbon dioxide, sulfur dioxide, and carbon monoxide were observed. A quantitative theory of device operation, capable of accounting for observed device leakage current and sensitivity, was developed. A prototype detection/alarm system was designed and built for use in demonstrating sensor performance.

Senturia, S. D.↗
NASA NTRS1977

Program Documentation for Elapsed Time to Oxygen and Hydrogen Caution and Warning System for Captive/active 1 and 3 Flights

High pressure gas storage simulation runs were made to compute the elapsed time from T-O disconnect (transfer to onboard reactant) to the caution and warning pressures for the primary oxygen (O2) and hydrogen (H2) systems of Orbiter Vehicle (OV) 101. The simulation runs were made for approach and landing test flights Captive/Active 1 and Captive/Active 3.

Hurst, J. E.↗
NASA NTRS1977

A survey of the status of and philosophies relating to cockpit warning systems

A survey was taken to study current cockpit caution and warning (c/w) systems, and to examine industry philosophies regarding c/w system design including current efforts to improve them. Guidelines currently in use were outlined and those which appear to have general acceptance, those which are considered ineffective or erroneous, and those with which there is broad disagreement as to validity, were delineated. Major airplane manufacturerd were surveyed and a manufacturer dealing specifically with aircraft instrumentation was consulted.

Cooper, G. E.↗
NASA NTRS1978

Ray tracing of gravity waves as a possible warning system for tornadic storms and hurricanes

Gravity waves with wave periods of 13 to 15 min and horizontal phase velocities of 90 to 220 m/sec were present in ground-based observations of the upper atmosphere during time periods when tornadoes were occurring and gravity waves with wave periods of 20 to 25 min and horizontal phase velocities of 100 to 200 m/sec were detected when a hurricane was present. Combinations of available neutral atmosphere data and model parameter values were used with a group ray tracing technique in an attempt to locate the sources of these waves. Computed sources of the waves with periods of 13 to 15 min were located within 50 km of the locations where tornadoes touched down from 2 to 4 h later. In the case of the waves with periods of 20 to 25 min it was found that the computed location of the source was roughly where the hurricane would be located 3 h after the waves were excited. The applicability of the present study to a tornado and hurricane warning system is noted.

Hung, R. J.↗
NASA NTRS1981

Feasibility of collision warning, precision approach and landing using GPS, volume 1

The use of GPS, with an appropriately configured data link, to enhance general aviation avionic functions encountered in the terminal area and on approach was investigated with emphasis on approach and landing guidance and collision warning. The feasibility of using differential GPS to obtain the precision navigation solutions required for landing was studied. Results show that the concept is sound. An experimental program was developed to demonstrate this concept. The collision avoidance/warning concept was examined through the development of a functional system specification.

Ruedger, W. H.↗
NASA NTRS1981

Feasibility study of a procedure to detect and warn of low level wind shear

A Doppler radar system which provides an aircraft with advanced warning of longitudinal wind shear is described. This system uses a Doppler radar beamed along the glide slope linked with an on line microprocessor containing a two dimensional, three degree of freedom model of the motion of an aircraft including pilot/autopilot control. The Doppler measured longitudinal glide slope winds are entered into the aircraft motion model, and a simulated controlled aircraft trajectory is calculated. Several flight path deterioration parameters are calculated from the computed aircraft trajectory information. The aircraft trajectory program, pilot control models, and the flight path deterioration parameters are discussed. The performance of the computer model and a test pilot in a flight simulator through longitudinal and vertical wind fields characteristic of a thunderstorm wind field are compared.

Turkel, B. S.↗