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Results for “MODIFICATIONS”

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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Chemical modification of poly(p-phenylene) for use in ablative compositions

Development of ablative materials based on modification of polyphenylene compounds is discussed. Chemical and physical properties are analyzed for application as heat resistant materials. Synthesis of linear polyphenylenes is described. Effects of exposure to oxyacetylene flame and composition of resultant char layer are presented.

Parker, J. A.↗
NASA NTRS1972

The influence of modifications of a fatigue loading history program on fatigue lifetime

Rectangular specimens of 7075 and 2014 aluminum alloys with two holes (stress concentration factor of 3.24) have been tested under axial fatigue loading on a six-rod test bed with modifications of the loading program, the surface particulars, and the frequency. The length of the precrack stage was investigated by use of a new crack detector. In most cases the two alloys behaved similarly, with similar life to crack start under the same loading. Some overloads lengthened the life. Truncation by omission of the lowest peak loads should be limited to about 20 percent of the ultimate load. Simplifying counting methods gave misleading results. Very thin surface layers of anodizing, protection by vinyl, dry nitrogen atmosphere, as well as stepwise reaming or grinding the surface of the holes, lengthened the life; thick anodized layers shortened the life. Compressing the hole surface by rolling had no influence. Frequencies at about 210 to 240 cpm produced shorter lives than those at 40 cpm. At 5.4 cpm the life was considerably longer. A model to better understand the precrack-stage fatigue mechanism is discussed.

Branger, J.↗
NASA NTRS1972

Modifications and additions to NASTRAN at Marshall Space Flight Center, 1969 - 1972

Modifications to NASTRAN code which result from the location, identification, and correction of errors or operational problem areas are reviewed. Addition of improved capability which is structural, executive system oriented, or utility in nature is also considered. NASTRAN efficiencies and inefficiencies are studied.

Jordon, A. J., Jr.↗
NASA NTRS1972

Potential value of satellite cloud pictures in weather modification projects

Satellite imagery for one project season of cloud seeding programs in the northern Great Plains has been surveyed for its probable usefulness in weather modification programs. The research projects and the meteorological information available are described. A few illustrative examples of satellite imagery analysis are cited and discussed, along with local observations of weather and the seeding decisions made in the research program. This analysis indicates a definite correlation between satellite-observed cloud patterns and the types of cloud seeding activity undertaken, and suggests a high probability of better and/or earlier decisions if the imagery is available in real time. Infrared imagery provides better estimates of cloud height which can be useful in assessing the possibility of a hail threat. The satellite imagery appears to be of more value to area-seeding projects than to single-cloud seeding experiments where the imagery is of little value except as an aid in local forecasting and analysis.

Biswas, K. R.↗
NASA NTRS1972

Expendable second stage reusable space shuttle booster. Volume 2: Technical summary. Book 3: Booster vehicle modifications and ground systems definition

A definition of the expendable second stage and space shuttle booster separation system is presented. Modifications required on the reusable booster for expendable second stage/payload flight and the ground systems needed to operate the expendable second stage in conjuction with the space shuttle booster are described. The safety, reliability, and quality assurance program is explained. Launch complex operations and services are analyzed.

Source record↗
NASA NTRS1972

Modification, static testing and delivery of one servoactuator

The development and performance testing of a servoactuator device are discussed. The detailed information includes the following: (1) modification description, (2) test data to include analyses, test procedures, and test data, (3) conclusions, and (4) recommendations. Diagrams of the servoactuator and photographs of the test equipment are presented. Descriptions of optimized system configurations are developed.

Hart, K. E.↗
NASA NTRS1973

Modification and updating of the Manned Activity Scheduling System (MASS) for shuttle and shuttle payloads analysis. Volume 1: Model specifications

The LRC MASS was modified and updated to include logic for efficient analysis of space shuttle payload operations. All MASS computer models were reviewed for compatibility with, and applicability to, the shuttle sortie mission. The MASS modification efforts were concentrated on two computer programs, the general scheduling model (GSM) and one day model (ODM). A new computer program, the DAYLIB Tape Processor, was developed to update the link between the GSM and ODM. The resulting MASS is an operationally efficient analytical tool that will allow a rapid assessment of shuttle and shuttle payload operations.

Ring, R. C.↗
NASA NTRS1973

A low speed wind tunnel test of the 0.050 scale NASA-JSC shuttle orbiter 089B to determine the longitudinal and lateral directional effects of control surface modifications

Wind tunnel tests to determine the longitudinal and lateral-directional effects of control surface modifications on the space shuttle orbiter aerodynamic characteristics are discussed. A total of 103 data runs were made which consisted of pitch runs through a range of zero to 28 degrees at a zero yaw angle and yaw runs from minus 6 to plus 6 degrees at various fixed pitch angles. At each data point, data from an internal strain gage balance was sampled with the digital data system. Also recorded were the model angles of pitch and yaw and the test section static pressure. Results are presented in the form of tabulated aerodynamic coefficient data about the model reference center.

Oldenbuttel, R. H.↗
NASA NTRS1974

Skylab facilities modifications at KSC

The facilities required at KSC to support Skylab were largely those facilities used by Apollo, modified for Skylab's particular needs. The one exception is the series of modifications to permit launching a Saturn IB from Complex 39. This new capability not only supported Skylab, but also supports the upcoming Apollo Soyuz, and any further S-IB launches that might be undertaken.

Phillips, J. D.↗
NASA NTRS1975

Diffusion pump modification promotes self-cleansing and high efficiency

Modifications eliminate contaminant substances from pump fluid during operation, which are principal causes of torpidity on evaporative surface. Diffusion pump is also acting as still. Resulting 100 percent vigorous working surface provides much greater molecular throughput and greatly improved efficiency.

Buggele, A. E.↗