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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

Lightweight Composite Reflectarray That Can Be Flattened, Folded, and Coiled for Compact Stowage

Herein is presented a design for a lightweight 5m 1m radio-frequency (RF) re ector that can be attened, folded, and coiled for compact stowage on board an ESPA-class spacecraft. The re ector is a re ectarray that operates at 3.2GHz. Compared to state- of-the-art technologies for RF re ectors, the presented design has advantages in terms of areal density, sti ness, deployed stability, and scalability. Thermal and structural analysis is presented to demonstrate deployed sti ness and thermoelastic stability of the proposed design. Thermal analysis is used to predict in- space deployed temperatures in an operational condition, and structural nite element analysis is used to predict deployed vibration modes and frequencies, and the thermoelastic deformation of the deployed re ector. Also presented are the fabrication, assembly, and testing of two one-third-scale-length full-scale-width 1:7m 1m test articles. These test articles are used to experimentally demonstrate RF functioning, stowage, deployment, and RF performance after deployment.

Pellegrino, Sergio↗
DOE OSTI2024

Cost-effective Conductor, Cable, and Coils for High Field Rotating Electric Machines

The purpose of the DOE-AMMTO-funded project was to significantly reduce industrial energy intensity through manufacturing innovations. The project focused on superconducting technology for industrial motors to dramatically increase efficiency. The bottleneck in deploying high temperature superconducting (HTS) motors was high cost and low yield of the conductor manufacturing process. The process yield is low because of the defects in the conductor, forcing the manufacturers to cut off defective sections after characterizing each millimeter. Additionally, the piece lengths tend to be low because of the defects. The project tackled the low-yield manufacturing process challenge by devising an innovative method to use defective conductors in bundled cables without losing performance by engineering current sharing among the conductors. The innovation not only lowers the cost of the conductor but also enhances the reliability of HTS motors and other devices to mitigate the defects that might form during the fabrication and operation of the device. With the increasing interest in REBa2Cu3O7-x (REBCO)-coated conductors for various power, energy, and magnet applications, ensuring the reliability of HTS devices is of significant interest. The EERE funding allowed us to make significant progress in understanding the defects in manufactured conductors and the implications of the defects in superconducting electric motors and other superconducting power and energy applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1972

Energy absorber uses expanded coiled tube

Mechanical shock mitigating device, based on working material to its failure point, absorbs mechanical energy by bending or twisting tubing. It functions under axial or tangential loading, has no rebound, is area independent, and is easy and inexpensive to build.

Johnson, E. F.↗
NASA NTRS1988

Analysis of coils of wire rope arranged for passive damping

Vibration dampers constructed with multiple loops of wire rope are studied. The literature on such devices is reviewed briefly, and dynamic and static models of them are examined. Fundamental and advanced NASTRAN models for wire rope damping are considered.

Cutchins, M. A.↗
NASA NTRS1991

Traveling-wave synchronous coil gun

An outline is presented of the coilgun concept, excitation, switching, brush commutation, power supply, and performance. It is shown that a traveling-wave synchronous coilgun permits independent adjustment of the magnetic field and armature current for high velocity at low armature mass fraction. Magnetic field energy is transferred from the rear of the wave to the front without passing through the power supply. Elaborate switching is required.

Elliott, David G.↗
NASA NTRS1995

Stability mechanical considerations, and AC loss in HTSC monoliths, coils, and wires

For monolithic high-T(sub c) superconductors (HTSC's) calculations are presented of: (1) the initial flux jump field, H(sub fj), in melt-processed YBCO based on a field and temperature dependent J(sub c), and (2) the radial and circumferential stresses in solid and hollow cylinders containing trapped magnetic flux. For model multi filamentary (MF) HTSC/Ag strands calculations are presented of: (1) the limiting filament diameters for adiabatic and dynamic stability, and (2) the hysteretic and eddy current components of AC loss. Again for MF HTSC/Ag composite strands the need for filamentary subdivision and twisting is discussed.

Sumption, M. D.↗
NASA NTRS2008

Synthesis and Compatibility of Ionic Liquid Containing Rod-Coil Polyimide Gel Electrolytes with Lithium Metal Electrodes

A highly cross-linked polyimide-polyethylene oxide copolymer has been synthesized that is capable of holding large volumes of liquid component, simultaneously maintaining good dimensional stability. An amine end capped oligomer was made that was imidized in solution, followed by reaction with a triisocyanate in the presence of desired additives at ambient temperature. Polymer films are able to hold over 4 times their weight in room temperature ionic liquid RTIL or carbonate solvent. Electrolytes were studied that contained varying amounts of RTIL, lithium trifluoromethanesulfonimide LiTFSi, and alumina nanoparticles. Electrochemical stability of these electrolytes with lithium metal electrodes was studied by galvanic cycling and impedance spectroscopy. Improved cycling stability and decreased interfacial resistance were observed when increasing amounts of RTIL and LiTFSi were added. The addition of small amounts of alumina further decreased interfacial resistance by nearly an order of magnitude. During the course of the study, cycling stability increased from less than 3 to greater than 1000 h at 60 C and 0.25 mA/cm2 current density.

Tigelaar, Dean M.↗