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Single helix, focused traveling wave tube for spacecraft telemetry systems and capable of delivering 25 watts power at 2.3 GHz at overall efficiency of 42.2 percent
General aviation research is leading to major advances in internal combustion engine control systems for single-engine, single-pilot aircraft. These advances promise to increase engine performance and fuel efficiency while substantially reducing pilot workload and increasing flight safety. One such advance is a single-lever power control (SLPC) system, a welcome departure from older, less user-friendly, multilever engine control systems. The benefits of using single-lever power controls for general aviation aircraft are improved flight safety through advanced engine diagnostics, simplified powerplant operations, increased time between overhauls, and cost-effective technology (extends fuel burn and reduces overhaul costs). The single-lever concept has proven to be so effective in preliminary studies that general aviation manufacturers are making plans to retrofit current aircraft with the technology and are incorporating it in designs for future aircraft.
Multichannel impeller consists of successive stage impellers arranged concentrically without clearances between them. Reduction in friction is predicted to increase pump efficiency by 5 to 10 percent.
Design procedures for compensating phased array antenna elements for impedance changes with scan angle
When liquid tank is full, baffle is held up against a stop on top of shaft to prevent restriction of flow from outlet. As tank is being emptied, baffle, floating on top of liquid surface, descends with liquid level toward outlet until it reaches its bottom stop. Baffle prevents gas pull-through until practically all liquid is emptied from tank.
Special lens shaping allows variation of focusing strength with radius. Lens can be either converging or diverging depending on charge of particles and direction of angular magnetic field. There is potential use for lens in particle analyzers, electron beam welding systems, microwave tube refocusing systems, and possible display type devices.
A floating baffle is described which rides up and down on a vertical shaft over a drain in a tank as the liquid level within the tank varies. When the baffle is in the raised position, the liquid is allowed to flow out of the drain at an unrestricted rate. When the baffle is in the lowered position, pull-through of air or gas that is above the liquid is presented, which would interfere and reduce the flow of liquid from the tank.
Higher current and higher voltage can be obtained by using Schottky barrier device with wide band-gap semiconductor as top layer and lower band-gap semiconductor underneath. Significant amount of solar radiation that is not absorbed by side band-gap material will be absorbed by narrow band-gap material.
A method to calculate spur gear system loss for a wide range of gear geometries and operating conditions was used to determine design requirements for an efficient gearset. The effects of spur gear size, pitch, ratio, pitch line velocity and load on efficiency were determined. Peak efficiencies were found to be greater for large diameter and fine pitched gears and tare (no-load) losses were found to be significant.
A method to calculate spur gear system power loss for a wide range of gear geometries and operating conditions is used to determine design requirements for an efficient gearset. The effects of spur gear size, pitch, ratio, pitch-line-velocity and load on efficiency are shown. A design example is given to illustrate how the method is to be applied. In general, peak efficiencies were found to be greater for larger diameter and fine pitched gears and tare (no-load) losses were found to be significant.
A novel method called "Dynamic Velocity Taper' to linearize the Pout versus Pin transfer characteristic that does not require any extraneous circuitry or tuning, has large bandwidth capabilities ( 10 percent) and offers also an increase in the intrinsic traveling wave tube (TWT) efficiency by 1 to 2 dB is described. In addition, the method permits the TWT to be operated at or near the synchronous voltage (b plus or minus o) which produces a flat small and large signal gain responses and low AM to PM conversion. The physics of the method and experimental verification are given. The implementation should have a significant impact on TWT performance and increase the channel capacity of communication satellites.
A novel method called 'Dynamic Velocity Taper' to linearize the Pout versus Pin transfer characteristic that does not require any extraneous circuitry or tuning, has large bandwidth capabilities (10 percent) and offers also an increase in the intrinsic traveling wave tube (TWT) efficiency by 1 to 2 dB is described. In addition, the method permits the TWT to be operated at or near the synchronous voltage (b plus or minus o) which produces a flat small and large signal gain responses and low AM to PM conversion. The physics of the method and experimental verification are given. The implementation should have a significant impact on TWT performance and increase the channel capacity of communication satellites. Previously announced in STAR as N84-21803
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The NASA Lewis Research Center's Remote Access Control Room (RACR) uses off-the-shelf video conferencing software integrated with existing facility data systems to provide access to the test data by networking from virtually anywhere in the country. The system allows research engineers in remote locations to participate in tests and monitor data in real time just as if they were present in the control room.
Second harmonic efficiency is limited by lateral and temporal separation of the ordinary and extraordinary components of the fundamental. A mode locked dual beam laser demonstrated these effects and a novel method to minimize them.
No abstract available
Determining the feasibility of the induced synthetic jet is key, and is still TBD. center dot Available LPT vane volume is sufficient for tens of resonators per span-wise hole spacing, so physically feasible. center dot Determination of acoustic attenuation requires accurate model of vane, resonator locations, flow field and incident waves. (TBD) center dot Determination of NOx reduction is also TBD.
Foamed-aluminum blocks act as passive heat exchanger to improve efficiency. Improved closed-cycle atmospheric scrubber, level of carbon dioxide, and water vapor are reduced without affecting temperature of airstream. Exchangers draw impurities from air without additional heaters of auxillary equipment.