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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Centaur space vehicle pressurized propellant feed system tests

Engine firing tests, using a full-scale flight-weight vehicle, were performed to evaluate a pressurized propellant feed system for the Centaur. The pressurant gases used were helium and hydrogen. The system was designed to replace the boost pumps currently used on Centaur. Two liquid oxygen tank pressurization modes were studied: (1) directly into the ullage and (2) below the propellant surface. Test results showed the two Centaur RL10 engines could be started and run over the range of expected flight variables. No system instabilities were encountered. Measured pressurization gas quantities agreed well with analytically predicted values.

Source record↗
NASA NTRS1972

Dual frequency microwave reflex feed

A dual frequency feed system for a Cassegrainian antenna is provided wherein two frequencies may be transmitted along a single boresight or received simultaneously using a single antenna.

Bathker, D. A.↗
NASA NTRS1972

Contamination damage avoidance concepts for propulsion feed system components.

The potential gain in the reliability of reusable long-term mission vehicles through the minimization of component damage due to the ingestion of particulate contamination by feed system components has been recognized by the NASA-LeRC and MDAC, and a program to investigate these problems has been completed. This investigation covered the determination of the cycle life of a typical 2-in. poppet type of shutoff valve in an uncontaminated GH2 environment and then compared this component performance with simulated operation with GN2 and LN2 containing controlled amounts of AL2O2 contaminant particles. The original valve design was tested for contamination damage tolerance characteristics under full flow and cyclic operating conditions, redesigned to improve the damage tolerance to contaminants and then retested. A second method of approach to damage tolerance control was investigated through the evaluation of various types of particulate separation devices. The study included various types of dynamic separators but did not cover conventional filter assemblies.

Endicott, D. L.↗
NASA NTRS1974

Side wire feed for welding apparatus

Coaxial electrode arrangement has solid central electrode, insulated outer electrode, and transverse channel for feeding wire through tip of electrode assembly. Polymeric insulation is thrust aside by pressure, which is provided by separately operated mechanism acting through central electrode.

Arnett, J. C.↗
NASA NTRS1973

Diagnostics of sources of disturbances and distribution of vibrations over the width of a tape in tape-feed mechanisms

Disturbances created by certain assemblies and components of tape-feed mechanisms (TFM) and acting on a moving magnetic tape are studied. The method, based on elements of digital logic, is established by stress-strain diagrams of the longitudinal deformations and vibrations across the width of a magnetic tape. Experimental studies were carried out for determination of the functional relationships of longitudinal deformations in a section of magnetic tape to the magnitude of roller play, tension vibrations rate of movement, and elasticity of magnetic tapes. A block diagram of the measurements is shown. Appropriate digital computer algorithms and programs were proposed for statistical analysis of the data obtained. Estimates of the mathematical expectation, dispersion, intercorrelation function, energy spectral density, and distribution pattern of the random process values were calculated.

Kenstavichyus, A. B. B.↗
NASA NTRS1974

Variable beamwidth monopulse feed for Tracking and Data Relay Satellite (TDRS)

The Tracking and Data Relay Satellite with a set of circularly-polarized, amplitude-sensing monopulse patterns suitable for acquiring and tracking user spacecraft at Ku-band (15.0 GHz) is discussed. The possibility of increasing the less than 0.4-degree half-power beamwidth of the data beam to almost 1.0 degree during the acquisition phase is predicated on the use of feeds situated in the first bright-ring of the Airy diffraction structure. A complex-vector simulation equivalent to the Kirchhoff-Kottler or Franz formulations is used to compute transmitted and received field information for a dual-reflector (Cassegrain) antenna configuration in a three-dimensional space.

Schmidt, R. F.↗
NASA NTRS1973

Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution

Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

Wydeven, T.↗
NASA NTRS1974

Dual S and Ku-band tracking feed for a TDRS reflector antenna

The results are presented of a trade study designed to identify a synchronous satellite antenna system suitable for receiving and transmitting data from lower orbiting satellites at both S- and K sub u-bands simultaneously as part of the Tracking and Data Relay Satellite System. All related problems associated with maintaining a data link between two satellites with a K sub u-band half-power beamwidth of 0.4 db are considered including data link maintenance techniques, beam pointing accuracies, gimbal and servo errors, solar heating, angle tracking schemes, acquisition problems and aids, tracking accuracies versus SNR, antenna feed designs, equipment designs, weight and power budgets, and detailed candidate antenna system designs.

Pullara, J. C.↗
NASA NTRS1979

Optimizing multislot feeds for reflecting antennas

Multislot feed corrects phase errors in reflecting antennas. Variables are reduced by considering symmetry and corrective effect of each phase mode. Overall computation concerning calculation of correct phase angles while optimizing main beam efficiency is simplified by analysis used parabolic torus reflector aboard Space Shuttle.

Waineo, D. K.↗
NASA NTRS1977

Proceedings of the conference on Coal Feeding Systems

Development of coal feed systems for coal gasification, fluidized bed combustion, and magnetohydrodynamic applications is discussed. Process operations experience, energy conversion efficiency, and environment effects are among the factors considered.

Source record↗
NASA NTRS1977

Pressurized feeding on the GEGAS system

A continuous process to feed coal directly into a pressurized gasifier is described. Coal fines are heated and mixed with a recycled tar binder and extruded through a novel die system against gasifier pressure. Performance data on a 2 in. system is given and scale up to a larger 6 in. system is described.

Furman, A. H.↗
NASA NTRS1977

A novel dry coal feeding concept for high-pressure gasifiers

A novel dry coal feeding concept was developed for injecting ground coal into high-pressure gasifiers. Significant power savings are projected because the coal is injected directly with a ram and there is no requirement for pumping large volumes of gas or fluid against pressure. A novel feature of the concept is that a new seal zone is formed between the ram and injection tube each cycle. The seal zone comprises a mixture of a small quantity of finely ground coal and a fluid. To demonstrate the feasibility of the concept, coal was injected into a 1000-psi chamber with an experimental device having a 7-1/2-inch-diameter ram and a 28-inch-long stroke.

Trumbull, H. E.↗
NASA NTRS1977

Feeding the feeder

Too often the equipment used to move difficult to handle powdery material from a hopper to process creates a complex of devices whose end result falls short on good performance...simply because equipment design, in many cases, has not kept up with advanced technological concepts in fine powder handling. The Feeder, being the key to an efficient feed system, must be assured a continuous flow from the storage tank...without bridging, arching, spasmodic flow or uncontrolled flushing. The causes and effects of flow problems are discussed and also solutions are offered based on the combination of theoretical and practical experience.

Kurylchek, A. L.↗
NASA NTRS1977

Coal feed component testing for CDIF

Investigations conducted during the conceptual design of the Montana MHD Component Development and Integration Facility (CDIF) identified commercially available processing and feeding equipment potentially suitable for use in a reference design. Tests on sub-scale units of this equipment indicated that they would perform as intended.

Pearson, C. V.↗
NASA NTRS1977

The use of twin screw extruders for feeding coal against pressures of up to 1500 PSI

Recent tests with a twin-screw, co-rotating extruder which was successfully used to convey and feed coal against pressures of up to 1500 psi are described. Intermeshing and self-wiping, co-rotating twin-screws give greatly improved conveying and pressure built-up capabilities and avoid hangup and eventual decomposition of coal particles in the screw flights. The conveying action of intermeshing, self-wiping, co-rotating extruder systems approaches that of a positive displacement pump. With this feature, it is possible to maintain very accurate control over all aspects of product conveyance in the extruder, i.e., intake, conveyance and pressure buildup.

Wiedmann, W.↗
NASA NTRS1978

Low loss, flexible, lightweight corporate RF feed system for SAR antenna application

Mechanical and electrical efficiency constraints imposed by the SEASAT-A synthetic aperture radar antenna posed difficult design problems. After consideration of available standard cable and waveguide systems, it was determined that an optimum design could be obtained from a suspended substrate RF feed system. Size and mechanical flexibility constraints forced the design of a flexible, suspended substrate section capable of 180-degree flexure. Original design goal for insertion loss over power division was 1 db; measured results indicated 0.6 db maximum across the band. Multipactor testing of system components indicated system breakdown capability in excess of 4 kW compared to a specification input maximum of 1500 W.

Schiavone, F.↗
NASA NTRS1978

Reflex feed system for dual frequency antenna with frequency cutoff means

A reflex feed system is described for a dual frequency antenna such as one which transmits and receives both S and X band signals. The dichroic plate, normally employed for directing X band radiation away from the X band horn, is replaced by a flange about the opening of the X band horn.

Hartop, R. W.↗