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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 505 records · Page 28

All sources NASA NTRS DOE OSTI

NASA NTRS1972

Experimental physics characteristics of a heavy-metal-reflected fast-spectrum critical assembly

A zero-power critical assembly was designed, constructed, and operated for the purpose of conducting a series of benchmark experiments dealing with the physics characteristics of a UN-fueled, Li-cooled, Mo-reflected, drum-controlled compact fast reactor for use with a space-power electric conversion system. The range of the previous experimental investigations has been expanded to include the reactivity effects of:(1) surrounding the reactor with 15.24 cm (6 in.) of polyethylene, (2) reducing the heights of a portion of the upper and lower axial reflectors by factors of 2 and 4, (3) adding 45 kg of W to the core uniformly in two steps, (4) adding 9.54 kg of Ta to the core uniformly, and (5) inserting 2.3 kg of polyethylene into the core proper and determining the effect of a Ta addition on the polyethylene worth.

Heneveld, W. H.↗

NASA NTRS1973

Fire retardant cellulosic foam

Method mixture of cyanamide, phosphoric acid, and monobasic ammonium phosphates for preliminary treatment of paper. Papier-mache, in second step, is pulped in water and latex is added. Urea formaldehyde solution mixed to maximize foaming and resin dispersion is added. Mixture is then cast within 30 to 60 seconds and dried twice.

Luttinger, M.↗

NASA NTRS1972

Pilot performance with a simulated ILS independence pictorial display

As part of a general investigation of the effectiveness of pictorial displays for manual control and monitoring of aircraft approaches and landings, a simulator study was conducted in which pilot performance with three pictorial displays was evaluated. These displays differed in the type of guidance symbology added to the basic perspective runway display. The effect of decreased resolution and update rate of the runway image on pilot performance was also determined. The results indicate that for pictorial displays with added guidance symbology, there was a marked improvement in pilot performance compared to results of a previous study in which the display consisted of only a runway image and aircraft attitude.

Palmer, E.↗

NASA NTRS1973

Data-aided carrier tracking loops

The characteristics of a data-aided carrier tracking loop are discussed. The loop signal to noise ratio is improved in a phase-locked loop used for tracking a carrier an angle modulated communications system by a quadrature channel added to the phase locked loop. A d.c. signal derived from the quadrature channel is added to the signal fed back to the voltage controlled oscillator in the otherwise conventional phase-locked loop.

Lindsey, W. C.↗

NASA NTRS1972

Research for amino acids in lunar samples.

The study was primarily directed toward the examination of Apollo 14 lunar fines for indigenous amino acids or materials which could be converted to amino acids on hydrolysis with 6 N hydrochloric acid. Initial experiments were conducted to confirm the integrity of the derivatization reactions and reagents, and to optimize the gas-liquid chromatographic (GLC) instrumental and chromatographic system for the separation and flame ionization detection of the amino acid derivatives. In studies on the recovery of amino acids added to lunar fines, low recoveries were obtained when 10 ng of each amino acid were added to 50 mg of virgin fines, but the subsequent addition of 50 ng of each to the previously extracted sample resulted in much higher recoveries.

Gehrke, C. W.↗

NASA NTRS1973

Application of digital computer APU modeling techniques to control system design.

Study of the required controls for a H2-O2 auxiliary power unit (APU) technology program for the Space Shuttle. A steady-state system digital computer program was prepared and used to optimize initial system design. Analytical models of each system component were included. The program was used to solve a nineteen-dimensional problem, and then time-dependent differential equations were added to the computer program to simulate transient APU system and control. Some system parameters were considered quasi-steady-state, and others were treated as differential variables. The dynamic control analysis proceeded from initial ideal control modeling (which considered one control function and assumed the others to be ideal), stepwise through the system (adding control functions), until all of the control functions and their interactions were considered. In this way, the adequacy of the final control design over the required wide range of APU operating conditions was established.

Bailey, D. A.↗

NASA NTRS1973

Acquisition and analysis of coastal ground-truth data for correlation with ERTS-1 imagery

The author has identified the following significant results. Radiance profiles drawn along cruise tracks have been examined for use in correlating digital radiance levels with ground truth data. Preliminary examination results are encouraging. Adding weighted levels from the 4 MSS bands appears to enhance specular surface reflections while rendering sensor noise white. Comparing each band signature to the added specular signature ought to enhance non-specular effects caused by ocean turbidity. Preliminary examination of radiance profiles and ground truth turbidity measurements revealed substantial correlation.

Anikouchine, W. A.↗

NASA NTRS1974

Display requirements for the final approach and landing phase of an RPV mission

A two part investigation was conducted to determine the display requirements for the final approach and landing phase of a remotely piloted vehicle (RPV) mission, and to assess the relative merits of several possible display configurations. The objective of the first part of the investigation was to obtain subjective assessments of several display configurations, and to select the most promising display concepts for subsequent evaluation in terms of performance measures. A basic display consisting of a perspective image of terrain and runway, a horizon bar and an aircraft symbol was used, and guidance symbology was added to the basic displaying selected state variables. Initial results suggested that as guidance symbology is added to the basic display, pilot acceptance tends to increase. A point of diminishing returns is eventually reached, however, when additional information produces too much clutter, and makes it difficult for the pilot to process the displayed information.

Howard, J. C.↗

NASA NTRS1974

The Atmosphere Explorer power subsystem

The design and operation of the power subsystem for the Atmospheric Explorer spacecraft are discussed. The additional functional redundancy which was added in several component areas to improve the overall subsystem reliability is analyzed. The battery charging technique has been modified to include third electrode overcharge control. The automatic removal of all battery charge is provided to correct abnormally high battery voltages. An undervoltage detector has been added which removes all nonessential spacecraft loads when the battery voltage falls below a given level. All automatic functions can be over-ridden by ground command.

Obenschain, A.↗

NASA NTRS1974

Coherent receiver employing nonlinear coherence detection for carrier tracking

The concept of nonlinear coherence employed in carrier tracking to improve telecommunications efficiency is disclosed. A generic tracking loop for a coherent receiver is shown having seven principle feedback signals which may be selectively added and applied to a voltage controlled oscillator to produce a reference signal that is phase coherent with a received carrier. An eighth feedback signal whose nonrandom components are coherent with the phase detected and filtered carrier may also be added to exploit the sideband power of the received signal. A ninth feedback signal whose nonrandom components are also coherent with the quadrature phase detected and filtered carrier could be additionally or alternatively included in the composite feedback signal to the voltage controlled oscillator.

Lindsey, W. C.↗

NASA NTRS1974

The effect of canard and vertical tails on the aerodynamic characteristics of a model with a 59 deg sweptback wing at a Mach number of 0.30

An investigation has been conducted to determine the effects of canard, canard location, vertical tails, and vertical-tail location on the aerodynamic characteristics of a model having a 59 deg sweptback wing. The investigation was conducted at a Mach number of 0.30, at angles of attack up to 22 deg and at sideslip angles of 0 deg and plus or minus 5 deg. The results of the study indicate that adding the canard to the model had only a slight effect on the lift at the lower angles of attack. At the higher angles of attack there is a significant effect of canard height on lift, canard in the high location (above the wing chord plane) resulting in the highest lifts. The lift drag characteristics are predicted well for the configuration with the mid or high canard locations by combining a potential flow solution on the canard with a potential plus vortex solution on the wing. Variations in the height significantly affect the pitching-moment characteristics of the configuration; the configuration with the low or mid canard location exhibits an increase in stability at the higher lift coefficients, whereas the configuration with the high canard exhibits pitch-up. Adding the vertical tails in the outboard location caused a significant loss in lift at the higher angles of attack; this lift loss was eliminated by moving the vertical tails inboard.

Henderson, W. P.↗

NASA NTRS1974

Boron aluminum crippling strength shows improvement

Results are presented from an experimental program directed toward improving boron aluminum crippling strength. Laminate changes evaluated were larger filament diameter, improved processing, shape changes, adding steel-aluminum cross plies, reduced filament volume in corners, adding boron aluminum angle plies, and using titanium interleaves. Filament diameter and steel-aluminum cross plies have little effect on crippling. It is shown that better processing combined with appropriate shape changes improved crippling over 50 percent at both room temperature and 600 F. Tests also show that crippling improvements ranging from 20 to 40 percent are achieved using angle plies and titanium interleaves.

Otto, O. R.↗

NASA NTRS1974

Short-duration radio flares of UV Ceti stars

The UV Ceti-type stars YZ Canis Minoris, AD Leonis, Wolf 424, and V371 Orionis were monitored with the Arecibo radio telescope at meter wavelengths. A total of 26 flares were recorded on YZ CMi, AD Leo, and Wolf 424. The observed flares had shorter durations and smaller amplitudes than those previously reported in the literature. Rates of radio-flare detection are similar to those found optically.

Spangler, S. R.↗

NASA NTRS1974

Earth resources data analysis program, phase 2

The efforts and findings of the Earth Resources Data Analysis Program are summarized. Results of a detailed study of the needs of EOD with respect to an applications development system (ADS) for the analysis of remotely sensed data, including an evaluation of four existing systems with respect to these needs are described. Recommendations as to possible courses for EOD to follow to obtain a viable ADS are presented. Algorithmic development comprised of several subtasks is discussed. These subtasks include the following: (1) two algorithms for multivariate density estimation; (2) a data smoothing algorithm; (3) a method for optimally estimating prior probabilities of unclassified data; and (4) further applications of the modified Cholesky decomposition in various calculations. Little effort was expended on task 3, however, two reports were reviewed.

Source record↗

NASA NTRS1975

Acoustical characteristics of the NASA Langley full scale wind tunnel test section

The full-scale wind tunnel at NASA-Langley Research Center was designed for low-speed aerodynamic testing of aircraft. Sound absorbing treatment has been added to the ceiling and walls of the tunnel test section to create a more anechoic condition for taking acoustical measurements during aerodynamic tests. The results of an experimental investigation of the present acoustical characteristics of the tunnel test section are presented. The experimental program included measurements of ambient nosie levels existing during various tunnel operating conditions, investigation of the sound field produced by an omnidirectional source, and determination of sound field decay rates for impulsive noise excitation. A comparison of the current results with previous measurements shows that the added sound treatment has improved the acoustical condition of the tunnel test section. An analysis of the data indicate that sound reflections from the tunnel ground-board platform could create difficulties in the interpretation of actual test results.

Abrahamson, A. L.↗

NASA NTRS1975

Effect of wing planform and canard location and geometry on the longitudinal aerodynamic characteristics of a close-coupled canard wing model at subsonic speeds

A generalized wind-tunnel model with canard and wing planforms typical of highly maneuverable aircraft was tested in the Langley 7- by 10-foot high-speed tunnel at a Mach number of 0.30 to determine the effect of canard location, canard size, wing sweep, and canard strake on canard-wing interference to high angles of attack. The major results of this investigation may be summarized as follows: the high-canard configuration (excluding the canard strake and canard flap), for both the 60 deg and 44 deg swept leading-edge wings, produced the highest maximum lift coefficient and the most linear pitching-moment curves; substantially larger gains in the canard lift and total lift were obtained by adding a strake to the canard located below the wing chord plane rather than by adding a strake to the canard located above the wing chord plane.

Gloss, B. B.↗

NASA NTRS1976

Faceted solar energy collectors

Two concepts enhance efficiency and flexibility of solar collectors: faceting collector surface and adding coloring agent to working fluid. Collector can be placed on existing structures and oriented to take advantage of position of sun. By adding coloring agent to working fluid, total absorbance can be increased and altered if required.

Segna, D. R.↗

NASA NTRS1975

Problem areas in the use of the firefly luciferase assay for bacterial detection

By purifying the firefly luciferase extract and adding all necessary chemicals but ATP in excess, an assay for ATP was performed by measuring the amount of light produced when a sample containing soluble ATP is added to the luciferase reaction mixture. Instrumentation, applications, and basic characteristics of the luciferase assay are presented. Effect of the growth medium and length of time grown in this medium on ATP per viable E. coli values is shown in graphic form, along with an ATP concentration curve showing relative light units versus ATP injected. Reagent functions and concentration methods are explored. Efforts to develop a fast automatable system to detect the presence of bacteria in biological fluids, especially urine, resulted in the optimization of procedures for use with different types of samples.

Picciolo, G. L.↗