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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Responses of a Modular Floating Wind TLP of MarsVAWT Supporting a 10 MW Vertical Axis Wind Turbine

Offshore floating wind foundations supporting a large wind turbine require a large yard facility or significant facility upgrades for their fabrication. To overcome the cost increase associated with facility upgrades, an innovative lightweight modular floating foundation is developed. The foundation comprises multiple modules to enable their assembly on water, offering many benefits and expanding fabrication options for a reduction in the overall cost of the platform. In this paper, the foundation modules and their assembly are briefly described, and an analysis of the platform’s dynamic responses is presented. The modular foundation includes a modular and lightweight tension leg platform (TLP) called “MarsVAWT” which supports a Darrieus 10 MW vertical axis wind turbine (VAWT). The platform is moored with highly pretensioned wire rope tendons. The responses of the platform are analyzed in the time domain in a semi-coupled manner under the turbine operating and parked conditions for an offshore site in the US Northeast. The tower base shear forces and bending moments increase considerably with the combination of wind and waves, compared to those with wind only. The tendon tensions on the weatherside in the operating condition at high wind speeds are comparable to the values of the 50-year extreme (parked). The tendon tension increases are highly correlated to the platform pitch, as well as the horizontal and vertical velocities and vertical acceleration at the tendon porch. The modular platform performances and tendon designs are confirmed to comply with industry standards and practices.

Boo, Sung Youn↗
DOE OSTI2022

The Arecibo Galaxy Environment Survey. XII. Optically Dark H i Clouds in the Leo I Group

Using data from the Arecibo Galaxy Environment Survey, we report the discovery of five H i clouds in the Leo I group without detected optical counterparts. Three of the clouds are found midway between M96 and M95, one is only from the southeast side of the well-known Leo Ring, and the fifth is relatively isolated. H i masses range from 2.6 × 10 6 M ⊙ to 9.0 × 10 6 M ⊙ , and velocity widths (W50) range from 16 to 42 km s -1 . Although a tidal origin is the most obvious explanation, this formation mechanism faces several challenges. For the most isolated cloud, the difficulties are its distance from neighboring galaxies and the lack of any signs of disturbance in the H i disks of those systems. Some of the clouds also appear to follow the baryonic Tully–Fisher relation between mass and velocity width for normal, stable galaxies, which is not expected if they are tidal in origin. Three clouds are found between M96 and M95 that have no optical counterparts but have otherwise similar properties and locations to the optically detected galaxy LeG 13. While overall we favor a tidal debris scenario to explain the clouds, we cannot rule out a primordial origin. If the clouds were produced in the same event that gave rise to the Leo Ring, they may provide important constraints on any model attempting to explain that structure.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Investigation of HTS Twisted Stacked-Tape Cable (TSTC) Conductor for High-Field, High-Current Fusion Magnets

The critical currents of a twisted single-tape were measured at 4.2 K in fields up to 17 T. It was confirmed that the critical current of a twisted-tape was similar to that of a flat tape in c-axis fields. Based on the single-tape critical-currents, a 40-tape (4-mm width) twisted stacked-tape cable (TSTC) conductor was experimentally evaluated at fields up to 17 T at 4.2 K. It was found that the Lorentz load degradation of the TSTC conductor was negligible at the end of a cyclic test. The TSTC cabling method has been considered to be suitable for developing a high-field high-current REBCO conductor for magnet applications as well as power transmission cables. A method to fabricate the inner legs of a D-shape toroidal field coil using a TSTC conductor has been discussed. This method allows the conductor to properly resist the transverse Lorentz load and mitigate ac loss issues by adopting a parallel-HTS-tape flat cable configuration where necessary.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1964

Simple circuit provides adjustable voltage with linear temperature variation

A bridge circuit giving an adjustable output voltage that varies linearly with temperature is formed with temperature compensating diodes in one leg. A resistor voltage divider adjusts to temperature range across the bridge. The circuit is satisfactory over the temperature range of minus 20 degrees centigrade to plus 80 degrees centigrade.

Moede, L. W.↗
NASA NTRS1965

Coaxial capacitor used to determine fluid density

Sensing device measures directly the density of compressible fluid existing simultaneously in both liquid and gaseous phases. The device is comprised of a capacitor connected as one leg of a bridge circuit, a power source, and an indicator calibrated to indicate density as a direct measurement.

Atkisson, E. A.↗
NASA NTRS1966

Calibrated clamp facilitates pressure application

Spring-loaded clamp applies specific pressure to hold materials together during bonding, welding, and machining. The clamp has two adjustable legs terminating in suction cups for easy attachment to a surface.

Source record↗
NASA NTRS1966

Alignment tool facilitates pin placement on irregular horizontal surfaces

Alignment tool facilitates spotting and cementing plastic pins on the true vertical to irregular concave and convex surfaces. The tool consists of a wood tripod with individually adjustable legs, a wood block with a hole for placing the pins and two spirit levels at a 90 degree angle for easy alignment.

Boyle, J. V.↗
NASA NTRS1965

Flux switching in multipath cores

Flux switching in multipath ferrimagnetic core materials - computational analyses for unloaded core, loaded core, core-diode-transistor binary counter, and loaded three-leg core

SWITCHING CIRCUIT↗
NASA NTRS1968

Distillation device supplies cesium vapor at constant pressure

Distillation apparatus in the form of a U tube supplies small amounts of pure cesium vapor at constant pressure to a thermionic converter. The upstream leg of the U tube is connected to a vacuum pump to withdraw noncondensable impurities, the bottom portion serves as a reservoir for the liquid cesium.

Basiulis, A.↗
NASA NTRS1966

Cardiovascular conditioning

Pulsatile leg cuffs effectiveness in lessening postflight orthostatic intolerance and blood pooling in lower extremities of Gemini 5 and 7 astronauts

Dietlein, L. F.↗