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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Qualitative and quantitative reasoning about thermodynamics

One goal of qualitative physics is to capture the tacit knowledge of engineers and scientists. It is shown how Qualitative Process theory can be used to express concepts of engineering thermodynamics. In particular, it is shown how to integrate qualitative and quantitative knowledge to solve textbook problems involving thermodynamic cycles, such as gas turbine plants and steam power plants. These ideas were implemented in a program called SCHISM. Its analysis of a sample textbook problem is described and plans for future work are discussed.

Skorstad, Gordon↗
NASA NTRS1990

Advanced NDE techniques for quantitative characterization of aircraft

Recent advances in nondestructive evaluation (NDE) at NASA Langley Research Center and their applications that have resulted in quantitative assessment of material properties based on thermal and ultrasonic measurements are reviewed. Specific applications include ultrasonic determination of bolt tension, ultrasonic and thermal characterization of bonded layered structures, characterization of composite materials, and disbonds in aircraft skins.

Heyman, Joseph S.↗
NASA NTRS1989

Three-dimensional quantitative flow diagnostics

The principles, capabilities, and practical implementation of advanced measurement techniques for the quantitative characterization of three-dimensional flows are reviewed. Consideration is given to particle, Rayleigh, and Raman scattering; fluorescence; flow marking by H2 bubbles, photochromism, photodissociation, and vibrationally excited molecules; light-sheet volume imaging; and stereo imaging. Also discussed are stereo schlieren methods, holographic particle imaging, optical tomography, acoustic and magnetic-resonance imaging, and the display of space-filling data. Extensive diagrams, graphs, photographs, sample images, and tables of numerical data are provided.

Miles, Richard B.↗
NASA NTRS1989

Quantitative NDE applied to composites and metals

Research at the NASA/Langley Research Center concerning quantitative NDE of composites and metals is reviewed. The relationship between ultrasonics and polymer cure is outlined. NDE models are presented, which can be used to develop measurement technologies for characterizing the curing of a polymer system for composite materials. The models can be used to determine the glass transition temperature, the degree of cure, and the cure rate. The application of the model to control autoclave processing of composite materials is noted. Consideration is given to the use of thermal diffusion models combined with controlled thermal input measurements to determine the thermal diffusivity of materials. Also, a two-dimensional physical model is described that permits delaminations in samples of Space Shuttle Solid Rocket Motors to be detected in thermograms in the presence of cooling effects and uneven heating.

Heyman, Joseph S.↗
NASA NTRS1991

Quantitative nondestructive evaluation: Requirements for tomorrow's reliability

Quantitative Nondestructive Evaluation (QNDE) is the technology of measurement, analysis, and prediction of the state of material/structural systems for safety, reliability, and mission assurance. QNDE has impact on everyday life from the cars we drive, the planes we fly, the buildings we work or live in, literally to the infrastructure of our world. Here, researchers highlight some of the new sciences and technologies that are part of a safer, cost effective tomorrow. Specific technologies that are discussed are thermal QNDE of aircraft structural integrity, ultrasonic QNDE for materials characterization, and technology spinoffs from aerospace to the medical sector. In each case, examples are given of how new requirements result in enabling measurement technologies, which in turn change the boundaries of design/practice.

Heyman, Joseph S.↗
NASA NTRS1989

Airborne radar and radiometer experiment for quantitative remote measurements of rain

An aircraft experiment has been conducted with a dual-frequency (10 GHz and 35 GHz) radar/radiometer system and an 18-GHz radiometer to test various rain-rate retrieval algorithms from space. In the experiment, which took place in the fall of 1988 at the NASA Wallops Flight Facility, VA, both stratiform and convective storms were observed. A ground-based radar and rain gauges were also used to obtain truth data. An external radar calibration is made with rain gauge data, thereby enabling quantitative reflectivity measurements. Comparisons between path attenuations derived from the surface return and from the radar reflectivity profile are made to test the feasibility of a technique to estimate the raindrop size distribution from simultaneous radar and path-attenuation measurements.

Kozu, Toshiaki↗
NASA NTRS1991

Surface temperature/heat transfer measurement using a quantitative phosphor thermography system

A relative-intensity phosphor thermography technique developed for surface heating studies in hypersonic wind tunnels is described. A direct relationship between relative emission intensity and phosphor temperature is used for quantitative surface temperature measurements in time. The technique provides global surface temperature-time histories using a 3-CCD (Charge Coupled Device) video camera and digital recording system. A current history of technique development at Langley is discussed. Latest developments include a phosphor mixture for a greater range of temperature sensitivity and use of castable ceramics for inexpensive test models. A method of calculating surface heat-transfer from thermal image data in blowdown wind tunnels is included in an appendix, with an analysis of material thermal heat-transfer properties. Results from tests in the Langley 31-Inch Mach 10 Tunnel are presented for a ceramic orbiter configuration and a four-inch diameter hemisphere model. Data include windward heating for bow-shock/wing-shock interactions on the orbiter wing surface, and a comparison with prediction for hemisphere heating distribution.

Buck, G. M.↗
NASA NTRS1991

Metamorphism of eucrite meteorites studied quantitatively using induced thermoluminescence

Induced thermoluminescence studies provide a new and quantitative means of determining relative metamorphic intensities for eucrite meteorites, the simplest and most ancient products of basaltic volcanism. Using this technique, it is shown that the eucrites constitute a continuous metamorphic series and not, as commonly assumed, two groups of metamorphosed and nonmetamorphosed meteorites. It is suggested that the method may have applications to other basalts.

Batchelor, J. David↗
NASA NTRS1990

Quantitative spectroscopy of hot stars

A review on the quantitative spectroscopy (QS) of hot stars is presented, with particular attention given to the study of photospheres, optically thin winds, unified model atmospheres, and stars with optically thick winds. It is concluded that the results presented here demonstrate the reliability of Qs as a unique source of accurate values of the global parameters (effective temperature, surface gravity, and elemental abundances) of hot stars.

Kudritzki, R. P.↗
NASA NTRS1991

A quantitative measure of phase correlations in density fields

A quantitative measure of the phase correlations in a density field is presented based on the location of the maxima of the Fourier components of that field. It is found that this measue can easily detect non-Gaussian behavior either in artificially constructed density fields or those that become non-Gaussian from gravitational clustering of Gaussian initial conditions. It is found that different initial power spectra produce somewhat distinguishable signals, and the signals are robust against sparse sampling.

Scherrer, Robert J.↗
NASA NTRS1992

Quantitative Evaluation Of Teleoperator Performance

Report describes experiments on remote manual control of robotic manipulator. Experiments conducted to evaluate quantitatively relative effectiveness of several control modes: various combinations of position control, rate control, remote compliance, and feedback from force and torque sensors. Tasks evaluated: removing thermal blanket, unbolting electrical panel, and handling bundles of electrical wires and electrical connectors on simulated solar Max satellite by means of remotely controlled robot in teleoperation laboratory.

Das, Hari↗
NASA NTRS1990

Quantitative infrared spectroscopy of minor constituents of the Earth's atmosphere

We obtain quantitative laboratory spectroscopic measurements of molecular constituents which are of importance in understanding the health of the Earth's atmosphere, and, in particular, emphasize those species which are important for understanding stratospheric kinetics or are used for long term monitoring of the stratosphere. Our measurements provide: (1) line and band intensity values which are needed to establish limits of detectability for as yet unobserved species and to quantify the abundance of those species which are observed; (2) line-positions, -half widths and pressure induced shifts are all needed for remote sensing techniques, and (3) data on the above basic molecular parameters at temperatures and pressures appropriate for the real atmosphere.

Chackerian, C., Jr.↗
NASA NTRS1992

Quantitative analysis of the effects of vertical magnetic fields on microsegregation in Te-doped LEC GaAs

Using near-IR transmission microscopy with computational absorption analysis, the effects of axial magnetic fields on micro- and macrosegregation during LP-LEC growth of GaAs were quantitatively investigated with a spatial resolution approaching 2 microns. Segregation inhomogeneities exceeding one order of magnitude are found to be related to fluid dynamics of the melt. The applicability of the BPS theory as well as the nonapplicability of the Cochran analysis are established.

Carlson, D. J.↗
NASA NTRS1992

Quantitative image processing in fluid mechanics

The current status of digital image processing in fluid flow research is reviewed. In particular, attention is given to a comprehensive approach to the extraction of quantitative data from multivariate databases and examples of recent developments. The discussion covers numerical simulations and experiments, data processing, generation and dissemination of knowledge, traditional image processing, hybrid processing, fluid flow vector field topology, and isosurface analysis using Marching Cubes.

Hesselink, Lambertus↗
NASA NTRS1993

Quantitative Tester And Reconditioner For Hand And Arm

Apparatus measures torques, forces, and motions of hand, wrist, forearm, elbow, and shoulder and aids in reconditioning muscles involved. Used to determine strengths and endurances of muscles, ranges of motion of joints, and reaction times. Provides quantitative data used to assess extent to which disuse, disease, or injury causes deterioration of muscles and of motor-coordination skills. Same apparatus serves as exercise machine to restore muscle performance by imposing electronically controlled, gradually increasing loads on muscles. Suitable for training and evaluating astronauts, field testing for workers' compensation claims, and physical therapy in hospitals. With aid of various attachments, system adapted to measure such special motions as pinching, rotation of wrist, and supination and pronation of the forearm. Attachments are gloves, wristlets, and sleeves.

Engle, Gary↗
NASA NTRS1992

Quantitative three-dimensional low-speed wake surveys

Theoretical and practical aspects of conducting three-dimensional wake measurements in large wind tunnels are reviewed with emphasis on applications in low-speed aerodynamics. Such quantitative wake surveys furnish separate values for the components of drag, such as profile drag and induced drag, but also measure lift without the use of a balance. In addition to global data, details of the wake flowfield as well as spanwise distributions of lift and drag are obtained. The paper demonstrates the value of this measurement technique using data from wake measurements conducted by Boeing on a variety of low-speed configurations including the complex high-lift system of a transport aircraft.

Brune, G. W.↗
NASA NTRS1992

Pitch Control Margin at High Angle of Attack - Quantitative Requirements (Flight Test Correlation With Simulation Predictions)

Aircraft designs that employ relaxed static stability (RSS) have the following problem: reduced pitching moments associated with RSS at high angle of attack (AOA) require a minimum pitch recovery moment or margin to guarantee a safe return from high AOA maneuvers at the most aft center of gravity (CG) encountered during a mission. Recent incidents and mishaps on Class IV aircraft have demonstrated a need for establishing quantitative longitudinal high AOA pitch control margin design guidelines for future aircraft. The Naval Air Warfare Center - Aircraft Division (NA WC-AD) is currently supporting an effort in conjunction with NASA Langley Research Center (NASA LaRC) to quantify such requirements. NASA LaRC has conducted a series of extensive simulation evaluations to define these design guidelines. The purpose of flight tests were to validate the overall research test methodology by comparing pilot comments, pilot ratings, and aircraft response characteristics gathered during inflight recoveries from high AOA conditions to those gathered during the fixed-base simulation sessions. Tests were completed on an F/A-18A in six flights for a total of 9.8 flight hours using an AOA and CG buildup sequence. Flight test results have validated the simulation studies in that pilot rating of high AOA nose-down recoveries were based on the short-term response interval in the forms of pitch acceleration and rate. In addition, flight test has demonstrated that high AOA pitch control margin can be evaluated using a stabilized pushover method.

Flight Testing↗
NASA NTRS1993

Quantitative results from the focusing schlieren technique

An iterative theoretical approach to obtain quantitative density data from the focusing schlieren technique is proposed. The approach is based on an approximate modeling of the focusing action in a focusing schlieren system, and an estimation of an appropriate focal plane thickness. The theoretical approach is incorporated in a computer program, and results obtained from a supersonic wind tunnel experiment evaluated by comparison with CFD data. The density distributions compared favorably with CFD predictions. However, improvements to the system are required in order to reduce noise in the data, to improve specifications of a depth of focus, and to refine the modeling of the focusing action.

Cook, S. P.↗