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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
NASA NTRS1982

Japanese MAGSAT Team

CHRONINT and investigator B tapes as well as CHRONFIN data are being analyzed using a graphical display to illustrate X.Y,Z components as well as their residuals from the MGST (4/81) model. In addition to surveys of the vicinity of Japan, an aerial magnetic survey was conducted around Syowa Station in the Antarctic. Relative data collected by polar orbiting satellites are also being studied. Techniques used to separate external and internal fields from the vector data along the orbital paths; analysis of the frequency of the toroidal current in the equatorial ionosphere; investigation of the sudden storm commencement observed by MAGSAT; determination of the structure of field aligned currents associated with substorms; and calculation of the total electric current passing through the plane encircled by the MAGSAT orbit are discussed.

Fukushima, N.↗
NASA NTRS1986

Modeling and investigative studies of Jovian low frequency emissions

Jovian decametric (DAM) and hectometric (HOM) emissions were first observed over the entire spectrum by the Voyager 1 and 2 flybys of the planet. They display unusual arc-like structures on frequency-versus-time spectrograms. Software for the modeling of the Jovian plasma and magnetic field environment was performed. In addition, an extensive library of programs was developed for the retrieval of Voyager Planetary Radio Astronomy (PRA) data in both the high and low frequency bands from new noise-free, recalibrated data tapes. This software allows the option of retrieving data sorted with respect to particular sub-Io longitudes. This has proven to be invaluable in the analyses of the data. Graphics routines were also developed to display the data on color spectrograms.

Menietti, J. D.↗
DOE OSTI2018

Quench Detection for High-Temperature Superconductor Conductors Using Acoustic Thermometry

Detecting local heat-dissipating zones in high-temperature superconductor (HTS) magnets is a challenging task due to slow propagation of such zones in HTS conductors. For long conductor lengths, voltage-based methods may not provide a sufficient sensitivity or redundancy, and therefore nonvoltage-based detection alternatives are being sought. One of those is the recently proposed method of Eigen Frequency Thermometry (EFT), which is an active acoustic technique for a fast and nonintrusive detection of 'hot spots,' utilizing temperature dependence of the conductor elastic moduli. In this work, we demonstrate the efficiency of EFT for detecting localized heating in a 1.2-m-long sample of REBCO tape immersed in liquid nitrogen, and benchmark sensitivity of the acoustic detection with respect to voltage, hot spot temperature, and power dissipation in the conductor. Modifying the original technique for differential mode of operation enables a much improved sensitivity, and adds a hot spot localization capability. Furthermore, we adapt this technique to subscale coils wound with REBCO CORC conductor built in the framework of U.S. Magnet Development Program. A successful thermal-based detection of dissipation onset at the critical current for a two-layer canted CORC dipole assembly is discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS2005

Electrodynamic Tether as a Thruster for MXER Studies

Electrodynamic propulsion based on the interaction of a conducting tether with the background magnetic field can be implemented across a range of system designs. Bare tethers, bare and insulated tethers with a balloon termination, and insulated tethers with a grid-sphere termination have been proposed for different applications. Electrodynamic tether as a thruster is currently proposed for the Momentum exchange Electrodynamic Reboost (MXER) Tether System that currently under development at NASA Marshal Space Flight Center. The choice of a tether design for a specific mission is based on the analysis of tether system performance. Different parameters describing tether performance such as system acceleration and efficiency can be calculated if the current distribution along the tether at the satellite trajectory is known. The code calculating the tether current collection for the bare and partly insulated tethers with the circular (wire) and rectangular (tape) cross-sections operating in the thrust mode has been developed and applied for MXER that is expected to operate in an equatorial elliptical orbit with perigee in the altitude range of 300-500km and apogee between 5000-8000km. The collected current is calculated as a function of the satellite velocity and the Earth s magnetic field, plasma parameters (plasma density and temperature), and tether parameters (tether length, the length of the bare segment, the type and the dimensions of the cross-section). The deviation of the collected current from the OML model due to the tether thickness and self-induced magnetic field (for tether with a circular cross-section) is taken into account.

Khazanov, G. V.↗
NASA NTRS1974

A magnetic bubble domain flight recorder

A feasibility model of an all-electronic bubble memory system has been constructed. It uses a small 60k bit bubble recorder consisting of 6 chips of 10k bits each mounted in three separate packages operating as a FIFO at a 150 KHz bubble data rate. In addition to serving as a direct tape recorder replacement, the bubble recorder can be programmed for random access to each individual chip for ranom block access operation or for self-checking or by-passing any malfunctioning memory chip. Read and write operations can be performed asynchronously from very low frequency up to basic recording field frequency. A large 50M bit prototype is planned.

Chen, T. T.↗
NASA NTRS1980

Magnetic Field Satellite (Magsat) data processing system specifications

The software specifications for the MAGSAT data processing system (MDPS) are presented. The MDPS is divided functionally into preprocessing of primary input data, data management, chronicle processing, and postprocessing. Data organization and validity, and checks of spacecraft and instrumentation are dicussed. Output products of the MDPS, including various plots and data tapes, are described. Formats for important tapes are presented. Dicussions and mathematical formulations for coordinate transformations and field model coefficients are included.

Berman, D.↗
DOE OSTI2015

SU-E-J-239: Influence of RF Coil Materials On Surface and Buildup Dose From a 6MV Photon Beam

Purpose: In order to perform real time tumour tracking using an integrated Linac-MR, images have to be acquired during irradiation. MRI uses RF coils in close proximity to the imaged volume. Given current RF coil designs this means that the high energy photons will be passing through the coil before reaching the patient. This study experimentally investigates the dose modifications that occur due to the presence of various RF coil materials in the treatment beam. Methods: Polycarbonate, copper or aluminum tape, and Teflon were used to emulate the base, conductor and cover respectively of a surface RF coil. These materials were placed at various distances from the surface of polystyrene or solid water phantoms which were irradiated in the presence of no magnetic field, a transverse 0.2T magnetic field, and a parallel 0.2T magnetic field. Percent depth doses were measured using ion chambers. Results: A significant increase in surface and buildup dose is observed. The surface dose is seen to decrease with an increasing separation between the emulated coil and the phantom surface, when no magnetic field is present. When a transverse magnetic field is applied the surface dose decreases faster with increasing separation, as some of the electrons created in the coil are curved away from the phantom’s surface. When a parallel field is present the surface dose stays approximately constant for small separations, only slightly decreasing for separations greater than 5cm, since the magnetic field focuses the electrons produced in the coil materials not allowing them to scatter. Conclusion: Irradiating a patient through an RF coil leads to an increase in the surface and buildup doses. Mitigating this increase is important for the successful clinical use of either a transverse or a parallel configuration Linac-MR unit. This project is partially supported by an operating grant from the Canadian Institute of Health Research (CIHR MOP 93752)

60 APPLIED LIFE SCIENCES↗
NASA NTRS2014

Nondestructive Evaluation Techniques for Development and Characterization of Carbon Nanotube Based Superstructures

Recently, multiple commercial vendors have developed capability for the production of large-scale quantities of high-quality carbon nanotube sheets and yarns. While the materials have found use in electrical shielding applications, development of structural systems composed of a high volume fraction of carbon nanotubes is still lacking. A recent NASA program seeks to address this by prototyping a structural nanotube composite with strength-toweight ratio exceeding current state-of-the-art carbon fiber composites. Commercially available carbon nanotube sheets, tapes, and yarns are being processed into high volume fraction carbon nanotube-polymer nanocomposites. Nondestructive evaluation techniques have been applied throughout this development effort for material characterization and process control. This paper will report on the progress of these efforts, including magnetic characterization of residual catalyst content, Raman scattering characterization of nanotube diameter, defect ratio, and nanotube strain, and polarized Raman scattering for characterization of nanotube alignment.

Wincheski, Buzz↗
DOE OSTI2024

Property Variations in Modern REBCO Coated Conductors from Multiple Manufacturers

The complex, multilayer structure of REBCO Coated Conductor (CC) poses significant challenges in the fabrication of high magnetic field devices where large stresses may initiate various forms of damage. Our goal is to peer below the cartoon representations of CC so that, amongst other things, we might better understand whether a CC from one manufacturer is interchangeable with that from another. This involves knowledge of a broad range of electromagnetic, geometric, microstructural, and J c (θ,B,T) properties, and their variations that collectively pose challenges for the fault tolerance of REBCO CC devices. Accordingly, comparative measurements of J c , visualization of flux penetration with Magneto-Optical Imaging (MOI), tape geometry from Scanning Electron Microscopy (SEM) of polished cross-sections, and extensive optical microscopy was performed on recently purchased samples from multiple manufacturers. Our analyses reveal many deviations from or characteristics absent from manufacturers’ specifications, while a comparison of different manufacturers’ mechanically and laser slit tapes shows a diverse array of slitting characteristics amongst the manufacturers and variation in properties those made to the same specification. Laser slit tapes from several manufacturers reveal ablated edges with damaged regions extending up to 50 μm, comparable to the damaged region found in the mechanically slit CC of this study. Overall, the aim of this study is to flesh out appropriate ways to understand the real conductor below the manufacturers’ cartoons to avoid surprises in our REBCO CC coil development program. The goal of this work was to perform a broad array of characterizations of the type needed for validation of purpose for making high field magnets: to our surprise we found a wide range of properties which greatly impact the mechanical strength and electromagnetic performance of solenoids composed of these conductors and reinforced the need for a broad characterization program for each conductor prior to its implementation.

Bradford, G.↗
NASA NTRS1981

Design, development, and field demonstration of a remotely deployable water quality monitoring system

A prototype water quality monitoring system is described which offers almost continuous in situ monitoring. The two-man portable system features: (1) a microprocessor controlled central processing unit which allows preprogrammed sampling schedules and reprogramming in situ; (2) a subsurface unit for multiple depth capability and security from vandalism; (3) an acoustic data link for communications between the subsurface unit and the surface control unit; (4) eight water quality parameter sensors; (5) a nonvolatile magnetic bubble memory which prevents data loss in the event of power interruption; (6) a rechargeable power supply sufficient for 2 weeks of unattended operation; (7) a water sampler which can collect samples for laboratory analysis; (8) data output in direct engineering units on printed tape or through a computer compatible link; (9) internal electronic calibration eliminating external sensor adjustment; and (10) acoustic location and recovery systems. Data obtained in Saginaw Bay, Lake Huron are tabulated.

Wallace, J. W.↗
NASA NTRS1972

The theoretical output of a ring core fluxgate sensor.

Demonstration that the output from a ring core sensor is directly proportional to the first time derivative of the product of dynamic permeability and magnetic intensity perturbation within the core caused by an external, uniform magnetic field. (Dynamic permeability is defined to be the slope of the hysteresis loop at a given point in time). Assuming that ellipsoidal shells can approximate the core, the demagnetization factor can be 'estimated' in the first order to be proportional to the first power of the quantity tape thickness (or number of wraps) divided by the core diameter. The constant of proportionality is determined from laboratory data. When an additional scale adjustment is applied to the resulting sensor output formula, the computed output tracks laboratory data for a range of sensor geometries.

Burger, J. R.↗
NASA NTRS1981

Investigation of Antarctic crust and upper mantle using MAGSAT and other geophysical data

Progress in processing and analysis of Investigator B MAGSAT data is reported. Data processing tasks required prior to data analysis, including translation and reformatting of tapes and development of computer routines, were performed. A scalar anomaly map of Antarctica is near completion. Data analysis included a qualitative correlation of NASA's 4/81 scalar map of Antarctica with other geopotential data and correlation of POGO and continental scale gravity data with MAGSAT data. A magnetic high was found to exist over the Ross Embayment.

Bentley, C. R.↗
DOE OSTI2014

Thickness dependence of the charge-density-wave transition temperature in VSe{sub 2}

A set of three-dimensional charge-density-wave (3D CDW) VSe{sub 2} nano-flakes with different thicknesses were obtained by the scotch tape-based micro-mechanical exfoliation method. Resistivity measurements showed that the 3D CDW transition temperature T{sub p} decreases systematically from 105 K in bulk to 81.8 K in the 11.6 nm thick flake. The Hall resistivity ρ{sub xy} of all the flakes showed a linear dependent behavior against the magnetic field with a residual electron concentration of the order of ∼10{sup 21} cm{sup −3} at 5 K. The electron concentration n increases slightly as the thickness d decreases, possibly due to the CDW gap is reduced with the decrease of the thickness.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Self-Powered Autonomous Sensing System for Arctic Ocean using a Frequency-multiplied Cylindrical Triboelectric Nanogenerator

An autonomous sensing system for collecting environmental observations in the Arctic region is critical for the estimation and prediction of climate change. Ocean waves are a great source of energy for these sensing systems but there has been limited research done on small-scale energy harvesting applications in the Arctic Ocean (subsea or surface). The available wave energy in the Arctic Ocean is lower than the typical ocean wave energy due to the low wave frequency, height, and operating months. Although the available wave energy depends on the specific location in the Arctic Ocean, the wave height decreases everywhere during the winter (Jan-March) [1]. Our target location in this work is the Beaufort and Chukchi Seas, which are ice covered for about 195 days per year leaving only a few months (June-November) for wave energy harvesting [2]. During these few months, the average wave frequency is 0.2 Hz and the most common wave frequency is around 0.15 Hz. Many energy harvesting methods are unsuitable for use in the Arctic Ocean because of to the cold temperature, low wave frequency, and low wave height. Triboelectric nanogenerators (TENG) are one of the few energy harvesting methods that excel in these conditions. Zhong et al. [3] designed a stacked pendulum-structured TENG for low-frequency ocean wave energy and reported the device generated a peak power density of 11.2 W/m3 under the low wave frequency of 0.2 Hz. The autonomous sensing system we developed for the Arctic Ocean, the Arctic-TENG, is based on a frequency-multiplied cylindrical TENG (FMC-TENG) which is an optimized TENG configuration for Arctic Ocean conditions due to the high power density under low-frequency wave conditions [4]. Figure 1 shows an FMC-TENG with multiple pairs of free-standing triboelectric-layer mode materials (Aluminum and FEP). The mass and magnet attached to the rotor store gravitational potential energy which is released as kinetic energy when the potential energy overcomes the repulsive magnetic force generated by the opposing magnet attached to the stator. This force unbalance triggers a sudden rotation and swinging motion of the mass which increases the angular velocity of the system and therefore enhances the output power of the TENG system. The main components of the Arctic-TENG are a 3D-printed rotor and stator, electric and dielectric material adhesive tape, and bearings. All these materials were cold-soaked and tested at -40 °C in a chest freezer. Both the 3D-printed parts and adhesives were confirmed to have a minimal effect from the cold temperature. Multiple bearings were tested and the starting torque of each one was compared both at room temperature and -40 °C. The bearing with the lowest starting torque at -40 °C was selected for use in the Arctic-TENG. The Arctic-TENG was tested using an out-of-water motor-driven wave simulator (Figure 2). The wave simulator allows for controlled testing at a wave height of 0.2 m and frequencies between 0.1 Hz to 0.5 Hz. This wave simulator was used for both room temperature and -40 °C testing. The Arctic-TENG generated significantly more power at -40 °C compared to room temperature for each frequency tested. The system stored energy in a supercapacitor via a power management circuit, and the amount of energy stored per day was calculated at different wave frequencies. Based on the conditions at the proposed deployment location (days of non-ice-covered ocean and wave frequency), the amount of stored energy per year from Arctic-TENG was calculated to be enough energy for two transmissions every day. Durability testing was completed on the Arctic-TENG at room temperature to determine the lifetime. The rotor of the Arctic-TENG was attached to a DC motor and spun continuously for several millions of cycles without degradation of the electrical output, demonstrating the feasibility for long-term operation.

Jung, Hyunjun↗
DOE OSTI2019

Two-Fold Reduction of J c Anisotropy in FeSe 0.5 Te 0.5 Films Using Low-Energy Proton Irradiation

High in-field performance and low anisotropy of critical current density J c are important for superconducting wires/tapes in rotating machine and magnet applications. Here, we report measurements of angular dependence of critical current density J c in pro-ton irradiated FeSe 0.5 Te 0.5 (FST) films at magnetic field up to 35 T. Here, we observed two-fold reduction in the J c anisotropy of FST films at 4.2 K and 15 Tesla magnetic field by irradiation with low-energy (190 keV) proton. In light of recent demonstration of roll-to-roll irradiation process successfully incorporated in the standard 2G HTS long length production wire, low-energy proton irradiation can be a practical solution to enhance the performance of iron-based super-conducting wires and tapes, as low-energy ion sources are inexpensive to operate and are readily available commercially.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Strength distributions of laminated FeNi-based metal amorphous nanocomposite ribbons

Metal Amorphous Nanocomposite (MANC) materials offer low losses at high magnetic switching frequency, enabling high power density motors with increased rotational speed. While MANCs have high strength, they are brittle. The use of motor components such as a rotor consisting of brittle material presents a reliability concern. Here, a promising MANC alloy is subjected to tensile tests and failure is observed with high-speed photography. A method is developed to prepare tensile specimens of laminated MANC and epoxy layers, simulating the stacking of an epoxy-impregnated tape-wound core. Tensile tests are conducted for single layer ribbon and for five- and ten-layer stacks of laminated material with thin layers of thermosetting epoxy. Failure distributions are shown to have increasing Weibull modulus with increasing layer count. The composite MANC material system is modeled using chain-of-bundles models. Using a k-failure model, we show that single ribbon strength distribution data can be used to predict well the failure distribution of laminated stacks. The agreement occurs when the assumed ineffective length, over which load is recovered in a failed layer, is comparable to the observed interlaminar separation length.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2023

The Addition of Boron to Melt-Spun Fe-6.5%Si Ribbons

Fe-6.5%Si has higher electrical resistivity, lower magnetocrystalline anisotropy, and lower magnetostriction than traditional Fe-3.2%Si silicon steel. The reduced iron losses of Fe-6.5%Si render it a highly favorable candidate for high-speed motors and transformers. However, large-scale production of wide Fe-6.5%Si tape by rapid solidification can be challenging mainly because of its high melting point. In this work, boron is alloyed to Fe-6.5%Si to reduce its melting temperature and interfacial energy to improve the alloy’s processability. Boron additions from 0.01 wt.% to 2.24 wt.% into Fe-6.5%Si and its effect on ribbon thickness, grain size, magnetic, and mechanical properties were studied. Further, minor boron alloying significantly changed the melt pool stability and wetting on the quench wheel and in turn increased the quench rate with minimum impact on the magnetic saturation and ductility. Boron addition of < 0.06 wt.% was also found beneficial to the magnetic property of the alloy by lowering both its hysteresis and eddy current losses.

36 MATERIALS SCIENCE↗
DOE OSTI2019

The Influence of Substrate Temperature of Seed Layer on the Structure and Superconducting Property of BaHfO{sub 3}-Doped Y{sub 0.5}Gd{sub 0.5}Ba{sub 2}Cu{sub 3}O{sub 7−δ} Film Prepared by Pulsed Laser Deposition

For various practical applications, excellent superconducting properties under magnetic field of REBa{sub 2}Cu{sub 3}O{sub 7−δ} (RE = rare earth elements (REBCO))-coated conductors are required, which can be fabricated by introducing artificial pinning centers, such as second-phase dopant. It is well known that BaMO{sub 3} (M = Zr, Sn, or Hf) can form self-organized nanorods in REBCO matrix and improve the critical current density (J{sub c}) under applied magnetic field. However, with increasing dopant level, the critical temperature T{sub c} and J{sub c} at 77 K in self-field decreased. In order to inhibit the degradation of the J{sub c} in self-field, we fabricated 5 mol% BaHfO{sub 3} (BHO)-doped Y{sub 0.5}Gd{sub 0.5}Ba{sub 2}Cu{sub 3}O{sub 7−δ} (YGBCO) seed layers on CeO{sub 2}-buffered IBAD-MgO tapes by pulse laser deposition (PLD) at a laser repetition of 10 Hz and different substrate temperature T{sub seed}, and subsequently deposited 5-mol% BHO-doped YGBCO upper layers at 160 Hz and higher substrate temperature. The effect of T{sub seed} on the quality of the 5-mol% BHO-doped YGBCO upper layer was investigated. With increasing T{sub seed} from 710 to 820 {sup ∘}C, the Δφ value of YGBCO (103) reflection first decreased and then increased, while the J{sub c} at 77 K increased with increasing T{sub seed} to 790 {sup ∘}C and decreased at higher T{sub seed}. The 5-mol% BHO-doped YGBCO layer with a seed layer deposited at 790 {sup ∘}C had the highest J{sub c} (77 K, self-field) of 4.0 MA/cm{sup 2}.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗