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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 109 records · Page 6

Building vibrations induced by noise from rotorcraft and propeller aircraft flyovers

Noise and building vibrations were measured for a series of helicopter and propeller-driven aircraft flyovers at WFF during May 1978. The building response data are compared with similar data acquired earlier at sites near Dulles and Kennedy Airports for operation of commercial jet transports, including the Concorde supersonic transport. Results show that noise-induced vibration levels in windows and walls are directly proportional to sound pressure level and that for a given noise level, the acceleration levels induced by a helicopter or a propeller-driven aircraft flyover cannot be distinguished from the acceleration levels induced by a commercial jet transport flyover. Noise-induced building acceleration levels were found to be lower than those levels which might be expected to cause structural damage and were also lower than some acceleration levels induced by such common domestic events as closing windows and doors.

Shepherd, Kevin P.↗

Rb-Sr and Sm-Nd chronology of an Apollo 17 KREEP basalt

The paper determines Sm-Nd and Rb-Sr mineral isochrons for an Apollo 17 KREEP (pigeonite) basalt clast from breccia 72275 collected from Boulder 1, Station 2 in the Valley of Taurus-Littrow. Sm-Nd analyses of the basalt yield a precise mineral isochron age of 4.08 +/-0.07 Ga for lambda(Sm-147) = 0.00654/Ga. The concordancy of Sm-Nd and Rb-Sr ages for the basalt suggests that it crystallized about 4.08 Ga ago. Distinct ages and initial Sr isotopic ratios for Apollo 17 KREEP basalts and Apollo 14 and 15 KREEP suggest that these two types of KREEP basalts were not derived from the same source. Apollo 17 KREEP basalts are contemporaneous with some Apollo 14 aluminous mare basalts. The ages and Sr and Nd isotopic data suggest that these two different types of basalts were produced from sources having similar Rb/Sr ratios but different Sm/Nd ratios.

Shih, C.-Y.↗

Age and isotopic relationships among the angrites Lewis Cliff 86010 and Angra dos Reis

The paper presents results of a wide-ranging isotopic investigation of the the Antarctic angrite LEW-86010 (LEW), and reassesses the type angrite Angra dos Reis (ADOR) in order to obtain precise radiometric ages and initial Sr isotopic compositions, and to search for the erstwhile presence of the short-lived nuclei Sm-146 and Al-26 via their daughter products. The isotopic compositions of Sm, U, Ca, and Ti were measured to allow a detailed appraisal to be made of the relations between, and the geneology of, these two angrites. LEW proves to be severely contaminated with modern terrestrial Pb, which is shown to result from terrestrial weathering. Concordant Pb-Pb model ages of pyroxene separates are obtained; uranium isotopic compositions are normal within error. Overall, striking age and isotopic similarities between LEW and ADOR were found, suggesting almost simultaneous production on the same asteroid, even though recent experimental studies imply that the two are not comagmatic.

Lugmair, G. W.↗

Aerospace crew station design

Consideration is given to spacecraft cockpits and work stations, commercial aircraft cockpits and crew stations, high performance aircraft cockpits and crew stations, and space stations and habitat crew stations. Particular attention is given to an historical review of NASA manned spacecraft crew stations, ESA spacelab crew stations, the evolution of commercial aircraft flight station design, Boeing 757/767 flight deck, a historical review of Concorde flight deck design, trends in the cockpit design of new European fighters, and state-of-the-art applications for Space Station crew interface design.

Carr, Gerald P.↗

What gross weight and range for an advanced HSCT?

A review of studies conducted in 1986 indicates that a 300 passenger, 5500 nautical mile range aircraft should weigh less than 400,000 pounds. Some data from a British Aerospace Society of Automotive Engineers (SAE) paper will be shown that purport to be an advanced Concorde that meets the range payload specifications at a gross weight of 360,000 pounds. Previous studies by Peter Coen of Langley Research Center support these results. The weight of a supersonic transport is important from the point of view of how much effort should be expended in developing lower sonic boom technologies. It is obvious that a 360,000 pound aircraft can be modified to a more acceptable boom level than a 700,000 pound one.

Driver, Cornelius↗

The NASA High-Speed Research Program

Since its inception, one of NASA's commitments has been to develop the technology to advance aeronautics. As such, a new High-Speed Research Program was activated to develop the technology for industry to build a High-Speed Civil Transport - a second generation Supersonic Transport (SST). The baseline for this program is the British Concorde, a major technological achievement for its time, but an aircraft which is now both technologically and economically outdated. Therefore, a second generation SST must satisfy environmental concerns and still be economically viable. In order to do this, it must have no significant effect on the ozone layer, meet Federal Air Regulation 36, Stage 3 for community noise, and have no perceptible sonic boom over populated areas. These three concerns are the focus of the research efforts in Phase 1 of the program and are the specific areas covered in the technical video report.

Beam, Sherilee F.↗

High speed civil transport

This report discusses the design and marketability of a next generation supersonic transport. Apogee Aeronautics Corporation has designated its High Speed Civil Transport (HSCT): Supercruiser HS-8. Since the beginning of the Concorde era, the general consensus has been that the proper time for the introduction of a next generation Supersonic Transport (SST) would depend upon the technical advances made in the areas of propulsion (reduction in emissions) and material composites (stronger, lighter materials). It is believed by many in the aerospace industry that these beforementioned technical advances lie on the horizon. With this being the case, this is the proper time to begin the design phase for the next generation HSCT. The design objective for a HSCT was to develop an aircraft that would be capable of transporting at least 250 passengers with baggage at a distance of 5500 nmi. The supersonic Mach number is currently unspecified. In addition, the design had to be marketable, cost effective, and certifiable. To achieve this goal, technical advances in the current SST's must be made, especially in the areas of aerodynamics and propulsion. As a result of these required aerodynamic advances, several different supersonic design concepts were reviewed.

Source record↗

Kinematics of compact groups and morphologies of the member galaxies

We present the results of a kinematical and morphological study of galaxies in the Hickson compact groups. The redshift survey of 457 galaxies has been completed. The great majority of the galaxies have velocities within about 1000 km/s(exp -1) of the median velocity of the group. The velocities of the groups range from 1380 to 41731 km/s(exp -1) with a median of 8889 km/s(exp -1), corresponding to a median distance of 89 h(exp -1)Mpc. With the addition of the radial velocity selection criterion, a relatively large sample of physically dense compact groups was defined. The nature of the velocity dispersion-morphology relation (Hickson, Kindl and Huchra 1989, hereafter HKH) is investigated. This is the tendency of groups with high velocity dispersions to contain fewer late type galaxies. We find that this strong correlation is not due to any sample selection effects. The morphology concordance in compact groups (HKH), which is the trend for galaxies in a group to have similar morphological types, can be fully explained by the velocity dispersion-morphology correlation. A significant correlation is found between crossing time and the fraction of gas-rich galaxies in the groups. Groups with short crossing times typically contain fewer late-type galaxies. This may be evidence that significant dynamical evolution has occurred in these groups.

Mendesdeoliveira, Claudia↗

The best-fit universe

Inflation provides very strong motivation for a flat Universe, Harrison-Zel'dovich (constant-curvature) perturbations, and cold dark matter. However, there are a number of cosmological observations that conflict with the predictions of the simplest such model: one with zero cosmological constant. They include the age of the Universe, dynamical determinations of Omega, galaxy-number counts, and the apparent abundance of large-scale structure in the Universe. While the discrepancies are not yet serious enough to rule out the simplest and most well motivated model, the current data point to a best-fit model with the following parameters: Omega(sub B) approximately equal to 0.03, Omega(sub CDM) approximately equal to 0.17, Omega(sub Lambda) approximately equal to 0.8, and H(sub 0) approximately equal to 70 km/(sec x Mpc) which improves significantly the concordance with observations. While there is no good reason to expect such a value for the cosmological constant, there is no physical principle that would rule out such.

Turner, Michael S.↗

The rebirth of supersonic transport

A development status evaluation is presented for the aerodynamic and propulsion system technologies that will be required to make a second-generation SST, or High Speed Civil Transport (HSCT) sufficiently (20 dB) quieter near airports and in supersonic cruise (sonic boom), less NO(x)-emitting, and longer-range than Concorde. NASA's Ames, Lewis, and Langley facilities are intensively concerned with the development of such an environmentally benign and economically feasible Mach 2.4 HSCT; efforts have concentrated on the design of a powerplant with the requisite specific fuel consumption, low emissions, and low noise.

Rosen, Robert↗

Flow and Drag Formulas for Simple Quadrics

This report gives the pressure distribution and resistance found by theory and experiment for simple quadrics fixed in an infinite uniform stream of practically incompressible fluid. The experimental values pertain to air and some liquids, especially water; the theoretical refer sometimes to perfect, again to viscid fluids. For the cases treated the concordance of theory and measurement is so close as to make a resume of results desirable. Incidentally formulas for the velocity at all points of the flow field are given, some being new forms for ready use derived in a previous paper. (author)

Zahm, A F↗

Supersonic airplane study and design

A supersonic airplane creates shocks which coalesce and form a classical N-wave on the ground, forming a double bang noise termed sonic boom. A recent supersonic commercial transport (the Concorde) has a loud sonic boom (over 100 PLdB) and low aerodynamic performance (cruise lift-drag ratio 7). To enhance the U.S. market share in supersonic transport, an airframer's market risk for a low-boom airplane has to be reduced. Computational fluid dynamics (CFD) is used to design airplanes to meet the dual constraints of low sonic boom and high aerodynamic performance. During the past year, a research effort was focused on three main topics. The first was to use the existing design tools, developed in past years, to design one of the low-boom wind-tunnel configurations (Ames Model 3) for testing at Ames Research Center in April 1993. The second was to use a Navier-Stokes code (Overflow) to support the Oblique-All-Wing (OAW) study at Ames. The third was to study an optimization technique applied on a Haack-Adams body to reduce aerodynamic drag.

Cheung, Samson↗

LEW88516 and SNC meteorites

We report on the isotopic composition of Pb and the concentration of Pb, U, and Th in a sample of LEW88516 (LEW). LEW was a 13-g stone recovered from Antarctica and was classified as a new member of the Shergottite group. This work was undertaken with the hope that LEW might yield new information to elucidate further the origin and evolution of Shergottites and other SNC meteorites. We have previously studied U-Th-Pb in other Shergottites, namely Shergotty, Zagami, EETA79001, and ALHA77005, as well as Nakhla. The results indicate that the initial leads of these Shergottites were well defined, were distinct from each other, and have high Pb-204/Pb-206 (from 0.0652 to 0.0739). These leads evolved in different reservoirs over most of solar system history in a low U-238/Pb-204(micro) is approximately equal to 5 environment. The U-Th-Pb isotopic systems are quite regular, which unambiguously indicates an event of U-Th-Pb fractionation at approximately 200 m.y. The details of the data arrays are complex. The young age is in general agreement with some of the ages obtained by other methods, but precise concordance between the different methods is not established. The new results on LEW are remarkably similar to those of ALHA77005 and support the other observations based on the mineralogy, petrology, and bulk composition. The clear distinction between the Shergottites and Nakhla is confirmed. We consider that the Shergottites and possibly all the SNC's were derived from an impact on the regolith of a differentiated terrestrial type planetary body (Mars?) with a high content of volatiles as compared to the earth.

Chen, J. H.↗

Combustion for future supersonic transport propulsion

Even with it's marginal performance, Concorde has demonstrated that supersonic civil aircraft are a practical proposition. A second generation machine will need sufficiently good performance for a robust operating system that can provide reliable, frequent service with competitive economics. Additionally, the propulsion system must be acceptable environmentally. That is it must create acceptable noise levels around airports and have acceptable emissions throughout its mission including cruise. Whatever devices may be used to improve the acceptability at subsonic flight conditions, the high operating temperatures at cruise can create difficult targets for the operation of the combustion system both mechanically and in the combustion process itself. While the driving force is ever better fuel consumption and weight to achieve economic viability, a future supersonic transport engine will have cycle temperatures limited only by the mechanical integrity of the major components. The environment of the major components in modern gas turbine engines is dominated by the air delivered by the compressor system. Consequently the maximum compression temperature is governed by materials available for the turbine and compressor discs. The continued improvement of the disc material leads to combustion inlet temperatures beyond today's experience and sets difficult targets for combustion system emissions. This is worsened by the requirement being at cruise and therefore maintained for the major part of the mission. Problems such as creep and oxidation of metallic parts are also considered.

B. W. Lowrie↗

Overview of NASA HSR high-lift program

The viewgraphs and discussion of the NASA High-Speed Research (HSR) Program being conducted to develop the technologies essential for the successful U.S. development of a commercial supersonic air transport in the 2005 timeframe are provided. The HSR program is being conducted in two phases, with the first phase stressing technology to ensure environmental acceptability and the second phase stressing technology to make the vehicle economically viable (in contrast to the current Concorde design). During Phase 1 of the program, a key element of the environmental emphases is minimization of community noise through effective engine nozzle noise suppression technology and through improving the performance of high-lift systems. An overview of the current Phase 1 High-Lift Program, directed at technology for community noise reduction, is presented. The total target for takeoff engine noise reduction to meet expected regulations is believed to be about 20 EPNdB. The high-lift research is stressing the exploration of innovative high-lift concepts and advanced flight operations procedures to achieve a substantial (approximately 6 EPNdB) reduction in community noise to supplement the reductions expected from engine nozzle noise suppression concepts; primary concern is focused on the takeoff and climbout operations where very high engine power settings are used. Significant reductions in aerodynamic drag in this regime will allow substantial reductions in the required engine thrust levels and therefore reductions in the noise generated.

Gilbert, William P.↗

Pre-bombardment crystallization ages of basaltic clasts from Antarctic howardites EET87503 and EET87513

Igneous clasts of basaltic eucrites are found in both howardites and polymict eucrites. We have studied the Rb-Sr and Sm-Nd isotopic systematics of a number of such clasts, of metamorphic grades 1-6, using the classification of Takeda and Graham. Here, we report Rb-Sr, (147)Sm-(143)Nd, and (145)Sm-(142)Nd studies of clast, 53 from Antarctic howardite EET87503. Although there is no evidence of disturbance of trace element systematics by Antarctic weathering, the Rb-Sr and conventional Sm-Nd isotopic systematics are severely disturbed, which we ascribe to thermal metamorphism. The Ar-Ar age spectrum shows ages ranging from approximately 3.85-3.55 Ga in an unusual 'down stairstep'. The (146)Sm-(142)Nd systematics, however, show the presence of live (146)Sm(t(sub 1/2) = 103 Ma), with (146)Sm/(144)Sm = 0.0061 +/- 0.0007 at the time of crystallization. This result is very similar to that previously obtained for basaltic clast, 18 from howardite EET87513 (paired with EET87503), which has concordant Rb-Sr and Sm-Nd ages of approximately 4.5 Ga. Thus, the two clasts are nearly the same age, and we conclude further than the EET87503,53 clast crystallized within 33 +/- 19 Ma of the LEW86010 angrite by comparing initial (146)Sm/(144)Sm to that of the angrite. We suggest that disturbances in the isotopic systematics of EET87503,53 are consanguineous with pyroxene homogenization.

Nyquist, L. E.↗

The use of a tactile interface to convey position and motion perceptions

Under normal terrestrial conditions, perception of position and motion is determined by central nervous system integration of concordant and redundant information from multiple sensory channels (somatosensory, vestibular, visual), which collectively yield vertical perceptions. In the acceleration environment experienced by the pilots, the somatosensory and vestibular sensors frequently present false information concerning the direction of gravity. When presented with conflicting sensory information, it is normal for pilots to experience episodes of disorientation. We have developed a tactile interface that obtains vertical roll and pitch information from a gyro-stabilized attitude indicator and maps this information in a one-to-one correspondence onto the torso of the body using a matrix of vibrotactors. This enables the pilot to continuously maintain an awareness of aircraft attitude without reference to visual cues, utilizing a sensory channel that normally operates at the subconscious level. Although initially developed to improve pilot spatial awareness, this device has obvious applications to 1) simulation and training, 2) nonvisual tracking of targets, which can reduce the need for pilots to make head movements in the high-G environment of aerial combat, and 3) orientation in environments with minimal somatosensory cues (e.g., underwater) or gravitational cues (e.g., space).

Rupert, A. H.↗

Main characteristics of the COMET/COMRADE experiments

Both the COMET (Collection en Orbite de Matiere Extra Terrestre) and the COMRADE (Collection of Micrometeorites, Residue and Debris Ejecta) programs are developed to the collection and analysis of the particles of various origins orbiting around the Earth at low altitudes (between approx. 300 and approx. 500 km). The COMET experiment is more specifically designed to be flown for a short period of time (a few days), in concordance with a meteor stream crossing the Earth. Thus, it results in a considerable enrichment in the collection of grains related to a given comet. The COMRADE experiment has been selected as a proposal for long-duration flights (a few months), in order to gain information on all sizes of particles present on low Earth orbits, including submicrometer grains. It has been accepted by ESA authorities for use on the EURECA 2 platform. The objectives of these studies are multiple. The use of passive detectors gives access to the chemical and isotopical properties of the grains in the micrometer size range, by analyzing either the particle remnant mixed with the target material, or the intact particle captured in a specific low-density material. The particle remnants of the micrometer-sized extraterrestrial grains, having impacted on purposely designed metallic collectors, are identified for complete and detailed chemical, isotopic, and organic analysis, thereby determining grain composition as well as the existence of organic and inorganic molecules, to be related with the possible cometary origin of the grains. Micrometer/submicrometer dust grains are also captured in a manner that ensures minimal particle degradation. The captured intact particles are returned to Earth for complete and detailed chemical, isotopic, spectral, mineralogical, and organic analysis.

Borg, J.↗