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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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X ray background angular structure comparison with optical galaxies spatial distribution, ruling out universe models with sources following cosmological mass distribution
Gamma phase composition estimation in Ni base superalloys by phase rule principles and analytic geometry
One hundred and twenty recorded sounds, including jets, turboprops, piston engined aircraft and helicopters were rated by a panel of subjects in a paired comparison test. The results were analyzed to evaluate a number of noise rating procedures in terms of their ability to accurately estimate both relative and absolute perceived noise levels. It was found that the complex procedures developed by Stevens, Zwicker and Kryter are superior to other scales. The main advantage of these methods over the more convenient weighted sound pressure level scales lies in their ability to cope with signals over a wide range of bandwidth. However, Stevens' loudness level scale and the perceived noise level scale both overestimate the growth of perceived level with intensity because of an apparent deficiency in the band level summation rule. A simple correction is proposed which will enable these scales to properly account for the experimental observations.
The techniques of propellant selection and characterization and the compromises that may be forced on the designer by the change of a propellant parameter are discussed. Rules for the selection of a general propellant type are presented. The characterization of various propellant properties is then approached parameter by parameter. Tailoring pitfalls and compromises are identified whenever possible, and appropriate cross references are used. Related design criteria monographs frequently are cited for a more detailed treatment of the topic under discussion. A list of source references is provided. These references, coupled with established texts in the field, should give the depth of knowledge necessary to the designer to aid in the selection of the most nearly optimum propellant for the design application.
Criteria and recommended practices for preventing stress-corrosion cracking from impairing the structural integrity and flightworthiness of space vehicles are presented. The important variables affecting stress-corrosion cracking are considered to be the environment, including time and temperature; metal composition, and structure; and sustained tensile stress. For designing spacecraft structures that are free of stress-corrosion cracking for the service life of the vehicle the following rules apply: (1) identification and control of the environments to which the structure will be exposed during construction, storage, transportation, and use; (2) selection of alloy compositions and tempers which are resistant to stress-corrosion cracking in the identified environment; (3) control of fabrication and other processes which may introduce residual tensile stresses or damage the material; (4) limitation of the combined residual and applied tensile stresses to below the threshold stress level for the onset of cracking throughout the service life of the vehicle; and (5) establishment of a thorough inspection program.
Current design practices are reviewed and assessed, and guidance is established for achieving greater consistency in design, reliability in the end product, and efficiency in the design effort. The total problem is discussed, and design elements involved in successful design are identified. Design criteria are described, and the rule, guide, limitation, or standard which must be imposed on each essential design element is given. Recommended practices are presented for satisfying each of the criteria.
Cost estimates and funding schedules are presented for a given configuration and costing ground rules. Cost methodology is described and the cost evolution from a baseline configuration to a selected configuration is given, emphasizing cases in which cost was a design driver. Programmatic cost avoidance techniques are discussed.
A six month program has been carried out to investigate various mechanisms for transferring technology to industry. This program has focused on transfer to the apparel industry through the Apparel Research Foundation. The procedure was to analyze the problem, obtain potentially relevant aerospace technology, and then transfer this technology to the industry organization. This was done in a specific case. Technology was identified relevant to stitchless joining, and this technology was transferred to the Apparel Research Foundation. The feasibility and ground rules for carrying out such activities on a broader scale were established. A specific objective was to transfer new technology from the industry organization to the industry itself. This required the establishment of an application engineering program. Another transfer mechanism tested was publication of solutions to industry problems in a format familiar to the industry. This is to be distinguished from circulating descriptions of new technology. Focus is on the industry problem and the manager is given a formula for solving it that he can follow. It was concluded that this mechanism can complement the problem statement approach to technology transfer. It is useful in achieving transfer when a large amount of application engineering is not necessary. A wide audience is immediately exposed to the technology. On the other hand, the major manufacturing problems which require a sophisticated technical solution integrating many innovations are less likely to be helped.
Tabulated data are presented on the costs, schedules, and technical characteristics for the space station phases C and D program. The work breakdown structure, schedule data, program ground rules, program costs, cost-estimating rationale, funding schedules, and supporting data are included.
Mass properties data for the 156 inch diameter, parallel burn, solid propellant rocket engine for the space shuttle booster are presented. Design ground rules and assumptions applicable to generation of the mass properties data are described, together with pertinent data sources.
The baseline for a space shuttle configuration utilizing two parallel-burn, 156-in.-diameter SRMs with three segments and techroll seal movable nozzles is presented. The concept and general economic benefits of SRM recovery are equally valid for the series-burn SRMs, provided that those SRMs are also designed for the same strength, stiffness, segmentation, and interchangeability as the present design, and that those SRMs are also recovered as individual units. Feasibility studies were initiated to investigate SRM recoverability. These studies were based upon recovery of the SRM boosters for the Titan 3C. Ground rules precluded SRM modification that required significant changes in motor qualification or schedule. Even with this restriction, the study determined that the recoverable booster concept was completely feasible, both technically and economically. Parachute recovery has been selected as the best method, principally because it can accomplish the task with a minimum development cost and time to achieve operational recovery status. This system affords the highest probability for achieving large cost reductions.
The structural and aerodynamic aspects of a general study of advanced transonic transports are presented. Aircraft designed to cruise at Mach numbers of 0.90, 0.98, and 1.15 were comparatively analyzed. The wings of all three aircraft employ supercritical sections, and the two aircraft with the highest cruise Mach numbers also employ fuselage area ruling. Structural/aerodynamic characteristics and interactions are investigated both parametrically and with the aid of an automated configuration optimization program. The effects of replacing conventional aluminum airframe structure by advanced filamentary composite (carbon/epoxy) structure receive particular attention. The methods employed in the structural/aerodynamic analysis are discussed.
A comparative study was performed to define an optimum portable life support system for suited operations inside and outside the Skylab Program. Emphasis was placed on utilization of qualified equipment, modified versions of qualified equipment, and new systems made up to state-of-the-art components. Outlined are the mission constraints, operational modes, and evaluation ground rules by which the Skylab portable life support system was selected and the resulting design.
Response of an experimental Fraunhofer line discriminator to a wide range of surficial deposits common in deserts and semideserts was tested in the laboratory and from an H-19 helicopter. No signals attributable to fluorescence were recorded during 540 miles of aerial traverses over southeastern California and west-central Arizona. It was concluded that exposed surfaces of target materials throughout the traverses were either nonluminescent at 5890 A or not sufficiently so to be detectable. It cannot be ruled out that the lack of fluorescence is partly attributable to surficial coatings of nonluminescent weathered material. The principal route surveyed from the air was from Needles, California to Furnace Creek Ranch, Death Valley and return, via the Amargosa River valley, Silurian Lake (dry), Silver Lake (dry), and Soda Lake (dry). Principal targets traversed were unconsolidated clastic sediments ranging from silty clay to cobbles, and a wide range of evaporite deposits.
The results are reported of acoustic measurements made on the 747 aircraft during visual approach monitor evaluation approaches. This display is designed to improve approach and landing precision under visual flight rule conditions. The purpose of the acoustic portion of the test was to measure, evaluate, and identify the noise levels during various types of aircraft approaches. Six noise measurement sites were positioned on the centerline of the approach ground track. The six noise measurement stations on the approach ground track were positioned between approximately 1 and 6 nautical miles from runway threshold. The 1-nautical mile point was chosen as the beginning of the ground track because it is specified as the approach measurement point in the FAA noise certification requirements. The 6-nautical mile point was chosen for its proximity to the point where the approach is initiated.
Procedures based on the method of local linearization and transonic equivalence rule were developed for predicting properties of transonic flows about certain classes of wing-body combinations. The procedures are applicable to transonic flows with free stream Mach number in the ranges near one, below the lower critical and above the upper critical. Theoretical results are presented for surface and flow field pressure distributions for both lifting and nonlifting situations.
If G is a grammar such that in each noncontext-free rule of G, the right side contains a string of terminals longer than any terminal string appearing between two nonterminals in the left side; then the language generated by G is context-free. Six previous results follow as simple corollaries of this theorem.
Multispectral data recognition and information extraction problems considered are: (1) signature extension for improved recognition processing over large areas; (2) choice of density functions for recognition decision rules; (3) channel selection for cost reduction; and (4) radiation balance mapping for interpretation of wide spectrum scanner data. The formulation of a simulation model and reprocessing of both aircraft and space data reduces scan angle variations and extends signatures from one altitude to another. Comparison of the usefulness of empirical density functions and that of Gaussian density functions for recognition processing establishes the advantages of normal assumption for individual fields in processing of multispectral scanner data. Also reported is a procedure for producing radiation balance maps from wide spectra by analyzing energy budgets of vegetation and other surface materials through partitioning net absorbed radiant energy and estimating incoming power density at both short and long wavelengths.