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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Improved wrap-curtain seal

Wrapped-curtain thermal seal closes gaps around doors, windows, partitions, and other movable assemblies. Designed for simplicity, seal uses no springs or other mechanical devices and is easily installed on already existing structures.

Schroeder, P. M.↗
NASA NTRS1979

Laser measuring system for wire-wrapped frame assemblies

The laser measuring system is designed to automatically measure and record the distances between small diameter wires on a wire wrapped grid frame assembly to an accuracy of 0.00635 mm (0.00025 in.). The system utilizes a helium-neon gas laser beam as the measuring instrument with a remote interferometer and retroreflector, a light source and photodetector to detect the wire positions, in conjunction with recording, display and printout units. The laser measuring system is utilized to perform precise automatic measurements for wire application machines or as an automatic feedback device for positioning wires and/or to adjust them for out of tolerance conditions.

Etzel, J. G.↗
NASA NTRS1982

Wire-Wrap Chatter Detector

Monitoring circuit responds to changes in resistance as little as 0.1 ohm. Has been used to detect defective wire-wrap connections during thermal and vibration tests. Defect is indicated to operator by light-emitting diode and by increase in count on a two-digit display.

Fisch, G. Z.↗
NASA NTRS1981

Offset wrap rib antenna concept development

A program to demonstrate large diameter offset reflector technology readiness through the development of ground testable, flight representative full size hardware also aims to provide a basis of data to allow confirmation of cost, performance, and size growth projections for the offset wrap ribe antenna design. An overview of the antenna system is presented and the operational deployment sequence examined. The ability to manufacture multiple segment ribs is assured and tooling for rib manufacture was redesigned to reduce cost. The selected mast design permits adequate stiffness and minimum stowed volume. Reflector and mast concerns and the program plan are summarized.

Woods, A. A., Jr.↗
NASA NTRS1983

Wrap-rib antenna concept development overview

The wrap rib antenna design of a parabolic reflector large space antenna is discussed. Cost estimates, design/mission compatibility, deployment sequence, ground based tests, and fabrication are discussed.

Woods, A. A., Jr.↗
NASA NTRS1990

Wrapped Wire Detects Rupture Of Pressure Vessel

Simple, inexpensive technique helps protect against damage caused by continuing operation of equipment after rupture or burnout of pressure vessel. Wire wrapped over area on outside of vessel where breakthrough most likely. If wall breaks or burns, so does wire. Current passing through wire ceases, triggering cutoff mechanism stopping flow in vessel to prevent further damage. Applied in other situations in which pipes or vessels fail due to overpressure, overheating, or corrosion.

Hunt, James B.↗
NASA NTRS2008

Strength, Fatigue, and Fracture Toughness of Ti-6Al-4V Liner from a Composite Over-Wrapped Pressure Vessel

It was demonstrated by way of experiment that Composite Over-wrapped Pressure Vessel (COPV) Ti-6Al-4V liner material can sustain the expected service loads and cycles. The experiments were performed as part of investigations on the residual life of COPV tanks being used in Space Shuttle Orbiters. Measured properties included tensile strength, compressive strength, reversed loading cycles to simulate liner proof strains, and cyclic fatigue loading to demonstrate the ability to sustain 1000 cycles after liner buckling. The liner material came from a salvaged 40 in. Columbia (orbiter 102) tank (SN029), and tensile strength measurements were made on both boss-transition (thick) and membrane regions (thin). The average measured yield strength was 131 ksi in the boss-transition and membrane regions, in good agreement with measurements made on 1970 s vintage forged plate stock. However, Young s modulus was 17.4+/-0.3 Msi, somewhat higher than typical handbook values (approx.16 Msi). The fracture toughness, as estimated from a failed fatigue specimen, was 74 ksi/sq in, in reasonable agreement with standardized measurements made on 1970 s vintage forged plate stock. Low cycle fatigue of a buckled test specimen implied that as-imprinted liners can sustain over 4000 load cycles.

Salem, Jonathan A.↗
DOE OSTI2025

Driving Force Dependent Photoinduced Charge Transfer Dynamics in Polymer-Wrapped Semiconducting Single-Walled Carbon Nanotubes

Here, we investigate the thermodynamic driving-force dependences of photoinduced charge separation (CS) and subsequent charge transfer dynamics in single-walled carbon nanotube (SWNT)–perylenediimide (PDI) donor–acceptor (D–A) superstructures. Pump–probe spectroscopy reveals that [SWNT (•+)n ]-(PDI –• ) n CS states form on an ∼100 fs time scale following photoexcitation; these dynamics are invariant across an ∼400 mV driving force range, indicating that SWNT hole polaron formation time scales are determined by nanotube lattice and solvent relaxation. These CS states feature SWNT hole polarons adjacent to (geminate) and nearby (nongeminate) PDI radical anions. Analysis of the free energy dependence for charge recombination (CR) of [SWNT •+ ] geminate -(PDI –• ) CS states highlights an ∼2 meV value for D–A electronic coupling (HAB) and ∼0.93 eV for the total reorganization energy (λ T ). A corresponding driving force dependence of the CR dynamics for [SWNT •+ ] nongeminate -(PDI –• ) CS states indicates a diminished H AB value (∼0.6 meV) and a larger λ T (∼1.1 eV), consistent with larger transfer distances. SWNT excitons that persist following photoinduced CS drive photooxidation of PDI –• components of [SWNT (•+)n ]-(PDI –• ) n CS states ( 1 SWNT* + PDI •– → PDI + SWNT •– ); this reaction manifests a significantly reduced λ T value (∼0.67 eV) as the initially prepared SWNT reduced state bears the character of a conduction band injected electron ([SWNT •– ] CB ). This reaction thus gives rise to relaxed, nongeminate SWNT electron and hole polarons on the same nanotube; these polarons react on a 10 2 ps time scale independent of the electronic structure of these SWNT-PDI superstructures.

anions↗
NASA NTRS1979

Study of wrap-rib antenna design

The results of a parametric design study conducted to develop the significant characteristics and technology limitations of space deployable antenna systems with aperture sizes ranging from 50 up to 300 m and F/D ratios between 0.5 and 3.0 are presented. Wrap/rib type reflectors of both the prime and offset fed geometry and associated feed support structures were considered. The significant constraints investigated as limitations on achievable aperture were inherent manufacturability, orbit dynamic and thermal stability, antenna weight, and antenna stowed volume. A data base, resulting in the defined maximum achievable aperture size as a function of diameter, frequency and estimated cost, was formed.

Wade, W. D.↗
NASA NTRS1982

Offset wrap rib antenna concept development

The demonstration of 50 to 150 m, STS compatible, offset antenna technology readiness is reported. Fabrication of a ground and flight testable partial 55 m reflector section and feed support structure is discussed. Reduction to practice through ground test verification is presently contained in the program. Key objectives for the program include the design of a compatible feed support structure and the fabrication and testing of critical components.

Woods, A. A., Jr.↗
NASA NTRS1981

Overview: Western Regional applications Program (WRAP) status

Interactions with all 14 of the states in the Western Region over the past three years are reviewed from NASA's perspective. Outreach and training programs using the M mobile analysis and training extension van, the University Program, classes at the Ames Center, demonstration tests with state agencies, and surveying the needs of local governments are highlighted. Planned activities, the continuance of ASVT's, and the impact of the budget cuts on NASA'S technology program are also considered.

Norman, S. M.↗
NASA NTRS1992

Wrap-up session

Listening to the case studies that were presented it became quite evident that the best data management systems were the ones where data managers and research scientists worked as a team developed in the early stages of project planning. Examples that were given included WOCE Data Assembly Centres e.g., Drifters, the Global Temperature Salinity Pilot Project (GTSPP) collaboration with Joint Analyses Centres in the U.S. and Australia, and JGOFS/BOFS development of Topical Centres. While each of these has some elements unique to the project, each had brought together 'teams' of Principal Investigators (PI's) and data management experts at an early stage of project development. Conversely, projects which had considered data management as a totally separate activity with lower priority often failed to provide the service required to meet scientific objectives. Therefore, the following actions should be brought to the attention of relevant groups within the IOC and other international organizations: (1) Publicize, at the national and international level, underway data/scientist collaborations that may be used as models in planning for the future. (2) Reduce adversarial situations where data managers and scientists appear to be in competition. (3) Colocation and other forms of collaboration often results in very high quality data sets and more timely data submission. Improved timeliness of data submissions was a common theme throughout the workshop and must be considered an important element in all future plans. Improvements in timely submission of data were noted. In order to continue this trend the advantages of timely submission of data must be stressed to those planning new ocean science projects.

Holland, Geoffrey↗