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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Technology Assessment of High Capacity Data Storage Systems: Can We Avoid a Data Survivability Crisis

The density of digital storage media in our information-intensive society increases by a factor of four every three years, while the rate at which this data can be migrated to viable long-term storage has been increasing by a factor of only four every nine years. Meanwhile, older data stored on increasingly obsolete media, are at considerable risk. When the systems for which the media were designed are no longer serviced by their manufacturers (many of whom are out of business), the data will no longer be accessible. In some cases, older media suffer from a physical breakdown of components - tapes simply lose their magnetic properties after a long time in storage. The scale of the crisis is compatible to that facing the Social Security System. Greater financial and intellectual resources to the development and refinement of new storage media and migration technologies in order to preserve as much data as possible.

Halem, M.↗
NASA NTRS1999

Technology Assessment of High Capacity Data Storage Systems: Can We Avoid a Data Survivability Crisis?

In a recent address at the California Science Center in Los Angeles, Vice President Al Gore articulated a Digital Earth Vision. That vision spoke to developing a multi-resolution, three-dimensional visual representation of the planet into which we can roam and zoom into vast quantities of embedded geo-referenced data. The vision was not limited to moving through space, but also allowing travel over a time-line, which can be set for days, years, centuries, or even geological epochs. A working group of Federal Agencies, developing a coordinated program to implement the Vice President's vision, developed the definition of the Digital Earth as a visual representation of our planet that enables a person to explore and interact with the vast amounts of natural and cultural geo-referenced information gathered about the Earth. One of the challenges identified by the agencies was whether the technology existed that would be available to permanently store and deliver all the digital data that enterprises might want to save for decades and centuries. Satellite digital data is growing by Moore's Law as is the growth of computer generated data. Similarly, the density of digital storage media in our information-intensive society is also increasing by a factor of four every three years. The technological bottleneck is that the bandwidth for transferring data is only growing at a factor of four every nine years. This implies that the migration of data to viable long-term storage is growing more slowly. The implication is that older data stored on increasingly obsolete media are at considerable risk if they cannot be continuously migrated to media with longer life times. Another problem occurs when the software and hardware systems for which the media were designed are no longer serviced by their manufacturers. Many instances exist where support for these systems are phased out after mergers or even in going out of business. In addition, survivability of older media can suffer from physical breakdown of components (e.g. tapes simply lose their magnetic properties after a long time in storage). As a result, a potential data survivability crisis is emerging. The scale of the crisis is comparable to that facing the Social Security System. Sometime in one or two decades, the exponential growth of data will become so great that many enterprises will not be able to migrate through their data to more permanent media during the lifetime of the media on which it resides. This will result in significant losses of data and their resultant impacts. To avoid this crisis, we need to plan and devote greater financial and intellectual resources are needed for the development and refinement of new storage media and migration technologies in order to preserve all data any organization determines worth saving permanently. This talk will explore technological solutions and suggested recommendations to address this technological data crisis.

Halem, Milton↗
DOE OSTI2016

Feasibility and electromagnetic analysis of a REBCO superconducting undulator

Recent advances in second-generation (2G) high temperature superconducting (HTS) coated conductors (CCs) have made them very attractive for new applications such as undulators. In this study, we have, for the first time, experimentally evaluated a design to validate applicability of 2G-HTS tapes for next generation undulator magnetic structures. A two-period undulator magnetic core was fabricated and 2G-HTS CCs were successfully wound onto the undulator core. The performance of the undulator magnetic structure was investigated and the highest engineering current density, J e , in such configuration reported yet was obtained. A new U-slit tape configuration was used to reduce the number of resistive joints and it was shown that with this new technique affordable levels of resistance values can be achieved for short length undulators. The ferromagnetic core was designed such as to accommodate winding the U-slit tapes. Finally, test results indicated that the winding and the soldering procedures are successful and do not deteriorate the performance of the 2G-HTS tapes.

2G-HTS↗
DOE OSTI2025

A Finite Element Study of Stress Reduction Techniques in REBCO HTS Conductor on a Round Cable (CORC) Cable

ReBCO high-temperature superconducting (HTS) tape is critical for achieving the high magnetic fields needed in next-generation particle accelerators. Enhancing the mechanical performance of ReBCO tape increases its critical current by reducing internal stress, especially in the superconducting layer. A finite element study examined how copper layer properties affect stress in ReBCO conductor on a round core (CORC) cables. The cable was modeled as a doubly supported beam under uniform compressive stresses."cable was modeled as a doubly supported beam under uniform load to simulate bending. A staged modeling approach from a single tape to a six-layer stack enabled validation and efficient parameter studies. Increasing the yield strength and Young s modulus of the copper layers reduced peak stress in the ReBCO layer. These results support development of improved tape stacks for high-field accelerator magnets

Mueller, Scott [Northern Illinois U.]↗
DOE OSTI2020

Superconductor with improved flux pinning at low temperatures

A REBCO superconductor tape that can achieve a lift factor greater than or equal to approximately 3.0 or 4.0 in an approximately 3 T magnetic field applied perpendicular to a REBCO tape at approximately 30 K. In an embodiment, the REBCO superconductor tape can include a critical current density less than or equal to approximately 4.2 MA/cm2 at 77 K in the absence of an external magnetic field. In another embodiment, the REBCO superconductor tape can include a critical current density greater than or equal to approximately 12 MA/cm2 at approximately 30 K in a magnetic field of approximately 3 T having an orientation parallel to a c-axis.

Selvamanickam, Venkat↗
DOE OSTI2022

Superconductor with improved flux pinning at low temperatures

A REBCO superconductor tape that can achieve a lift factor greater than or equal to approximately 3.0 or 4.0 in an approximately 3 T magnetic field applied perpendicular to a REBCO tape at approximately 30 K. In an embodiment, the REBCO superconductor tape can include a critical current density less than or equal to approximately 4.2 MA/cm2 at 77 K in the absence of an external magnetic field. In another embodiment, the REBCO superconductor tape can include a critical current density greater than or equal to approximately 12 MA/cm2 at approximately 30 K in a magnetic field of approximately 3 T having an orientation parallel to a c-axis.

Selvamanickam, Venkat↗
DOE OSTI2021

Characterization of edge damage induced on REBCO superconducting tape by mechanical slitting

Abstract Rare-earth barium-copper-oxide (REBCO) superconductors are high-field superconductors fabricated in a tape geometry that can be utilized in magnet applications well in excess of 20 T. Due to the multilayer architecture of the tape, delamination is one cause of mechanical failure in REBCO tapes. During a mechanical slitting step in the manufacturing process, edge cracks can be introduced into the tape. These cracks are thought to be potential initiation sites for crack propagation in the tapes when subjected to stresses in the fabrication and operation of magnet systems. We sought to understand which layers were the mechanically weakest by locating the crack initiation layer and identifying the geometrical conditions of the slitter that promoted or suppressed crack formation. The described cracking was investigated by selectively etching and characterizing each layer with scanning electron microscopy, laser confocal microscopy, and digital image analysis. Our analysis showed that the average crack lengths in the REBCO, LaMnO 3 (LMO) and Al 2 O 3 layers were 34 μ m, 28 μ m, and 15 μ m, respectively. The total number of cracks measured in 30 mm of wire length was between 3000 and 5700 depending on the layer and their crack densities were 102 cracks mm −1 for REBCO, 108 cracks mm −1 for LMO, and 183 cracks mm −1 for Al 2 O 3 . These results indicated that there are separate crack initiation mechanisms for the REBCO and the LMO layers, as detailed in the paper. With a better understanding of the crack growth behavior exhibited by REBCO tapes, the fabrication process can be improved to provide a more mechanically stable and cost-effective superconductor.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

A bi-layer barrier design for 122-type iron-based superconducting wires and tapes

Iron-based superconducting wires and tapes hold great promise for high-field magnet applications. A promising design for 122-type wires and tapes based on the powder-in-tube method is using silver and copper double-layer sheaths. For this design a heat treatment temperature below ~ 779 °C is required to prevent Ag-Cu liquid formation. However, this may be below the optimal heat treatment temperature for the critical current density, and still cannot prevent Ag-Cu interdiffusion occurring in the solid state. In this work we propose adding a niobium or tantalum or vanadium (or their alloys) barrier layer between the Ag and Cu to solve the Ag-Cu interdiffusion issue, given that the group-VB metals (vanadium, niobium, tantalum) are relatively inert to both Ag and Cu. To investigate the effectiveness of this design, BaFe 1.84 Co 0.16 As 2 wires and tapes with Ag/Cu and Ag/Ta/Cu sheaths, as well as Ba 0.6 K 0.4 Fe 2 As 2 wires and tapes with Ag/Cu and Ag/Nb/Cu sheaths, were fabricated. It was found that both the Ta and Nb layers kept integral after wire drawing, but after a large flat-rolling reduction the Ta layer broke while the Nb layer kept integral. In the tapes with Ag/Cu sheaths (without the Ta or Nb layer) Cu diffused through the Ag layer and into the powder cores during 740 °C heat treatment, while in the tapes with Ag/Nb/Cu sheaths the Nb layer effectively blocked Ag-Cu interdiffusion even at 900 °C. Further, this work demonstrates that Ta is a suitable barrier material for 122-type wires, while Nb is suitable for both wires and tapes. In this design using Ag/Nb (or Ta)/Cu sheaths, we can regard the outer Cu as the conductor matrix while the Ag and Nb (or Ta) serve as two layers of barriers that suppress reactions between the components. Thus, we call this design a “bi-layer barrier” design for 122-type wires and tapes.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Fusion Development and Technology (Final Technical Report for FC02-93ER54186)

The project is divided into three major tasks: 1) Magnet R&D i) Magnets Task 1 - Development of HTS Twisted Stacked-Tape Cable (TSTC) conductors for high field, high current magnets ii) Magnets Task 2– Development of Cryogenic Magnet Cooling Technology iii) Magnets Task 3 - National and International Collaboration 2) Electron Cyclotron Heating (ECH) of plasmas 3) FNSF Liquid Metals Study.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Low temperature superconductor and aligned high temperature superconductor magnetic dipole system and method for producing high magnetic fields

A dipole-magnet system and method for producing high-magnetic-fields, including an open-region located in a radially-central-region to allow particle-beam transport and other uses, low-temperature-superconducting-coils comprised of low-temperature-superconducting-wire located in radially-outward-regions to generate high magnetic-fields, high-temperature-superconducting-coils comprised of high-temperature-superconducting-tape located in radially-inward-regions to generate even higher magnetic-fields and to reduce erroneous fields, support-structures to support the coils against large Lorentz-forces, a liquid-helium-system to cool the coils, and electrical-contacts to allow electric-current into and out of the coils. The high-temperature-superconducting-tape may be comprised of bismuth-strontium-calcium-copper-oxide or rare-earth-metal, barium-copper-oxide (ReBCO) where the rare-earth-metal may be yttrium, samarium, neodymium, or gadolinium. Advantageously, alignment of the large-dimension of the rectangular-cross-section or curved-cross-section of the high-temperature-superconducting-tape with the high-magnetic-field minimizes unwanted erroneous magnetic fields. Alignment may be accomplished by proper positioning, tilting the high-temperature-superconducting-coils, forming the high-temperature-superconducting-coils into a curved-cross-section, placing nonconducting wedge-shaped-material between windings, placing nonconducting curved-and-wedge-shaped-material between windings, or by a combination of these techniques.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1991

Paramagnetic propellant orientation

Deep space or low earth orbital propellant tanks require a fluid orientation system prior to engine firing or transfer. Some propellants such as cryogenic hydrogen, oxygen, and air are paramagnetic and respond to electromagnetic fields. A simple magnetic scheme is described for propellant orientation and a video tape presentation is provided that demonstrates some effects of magnetic fields on liquid air and oxygen in a low gravity simulator using the Leidenfrost phenomenon. When these Leidenfrost drops intersect the field lines, their flight paths are altered, some directly into the poles, some to the edges, and others move out of the field.

Hendricks, R. C.↗
NASA NTRS1991

Paramagnetic propellant orientation

Deep space or low earth orbital propellant tanks require a fluid orientation system prior to engine firing or transfer. Some propellants such as cryogenic hydrogen, oxygen, and air are paramagnetic and respond to electromagnetic fields. A simple magnetic scheme is described for propellant orientation and a video tape presentation is provided that demonstrates some effects of magnetic fields on liquid air and oxygen in a low gravity simulator using the Leidenfrost phenomenon. When these Leidenfrost drops intersect the field lines, their flight paths are altered, some directly into the poles, some to the edges, and others move out of the field.

Hendricks, R. C.↗
DOE OSTI2014

Strongly enhanced vortex pinning from 4 to 77 K in magnetic fields up to 31 T in 15 mol.% Zr-added (Gd, Y)-Ba-Cu-O superconducting tapes

Applications of REBCO coated conductors are now being developed for a very wide range of temperatures and magnetic fields and it is not yet clear whether vortex pinning strategies aimed for high temperature, low field operation are equally valid at lower temperatures and higher fields. A detailed characterization of the superconducting properties of a 15 mol.% Zr-added REBCO thin film made by metal organic chemical vapor deposition, from 4.2 to 77 K under magnetic fields up to 31 T is presented in this article. Even at a such high level of Zr addition, T-c depression has been avoided (T-c = 91 K), while at the same time an exceptionally high irreversibility field H-irr approximate to 14.8 T at 77 K and a remarkably high vortex pinning force density F-p approximate to 1.7 TN/m(3) at 4.2 K have been achieved. We ascribe the excellent pinning performance at high temperatures to the high density (equivalent vortex matching field similar to 7 T) of self-assembled BZO nanorods, while the low temperature pinning force is enhanced by large additional pinning which we ascribe to strain-induced point defects induced in the REBCO matrix by the BZO nanorods. Our results suggest even more room for further performance enhancement of commercial REBCO coated conductors and point the way to REBCO coil applications at liquid nitrogen temperatures since the critical current density J(c)(H//c) characteristic at 77 K are now almost identical to those of fully optimized Nb-Ti at 4 K. (C) 2014 Author(s).

Xu, A↗
DOE OSTI2022

Rapid assessment of REBCO CC angular critical current density J c (B, T = 4.2 K, θ) using torque magnetometry up to at least 30 tesla

Abstract Detailed design of REBa 2 Cu 3 O 7 − x (REBCO)-based magnets ideally relies on knowledge of the full angular and wide temperature range characterization of the critical current I c of the REBCO coated conductors (CC) at high magnetic fields. In practice, however, obtaining I c ( B , T , θ ) data by the commonly used electrical transport technique is expensive, tedious, and difficult, due to high critical current values that exceed 2000 A for B | | a b -plane ( θ = 90 deg). The conductors are often damaged during angular transport measurements at angles approaching the ab -plane. Therefore, so far, REBCO magnets have been designed without full I c ( B , T , θ ) data sets. Here, we present J c ( B , T , θ ) results for more than twenty samples of CC all made to the same advanced pinning specification produced by SuperPower Inc. For this, we employed torque magnetometry, benchmarking the results to transport I c measurements mostly made away from ab -plane, finding good agreement with scaling factors ≈1–1.3. What is striking is the huge variety of properties exhibited by the samples, even for CC made recently. Given the huge attention now being paid to the effects of screening currents and to the torques generated by offsets between the tape plane and the local magnetic field vector, our data set suggests some caution in detailed design of such magnets without having data of the type presented here.

Physics↗
DOE OSTI2019

AMS-100: The next generation magnetic spectrometer in space – An international science platform for physics and astrophysics at Lagrange point 2

The next generation magnetic spectrometer in space, AMS-100, is designed to have a geometrical acceptance of 100 m 2 sr and to be operated for at least ten years at the Sun–Earth Lagrange Point 2. Compared to existing experiments, it will improve the sensitivity for the observation of new phenomena in cosmic rays, and in particular in cosmic antimatter, by at least a factor of 1000. The magnet design is based on high temperature superconductor tapes, which allow the construction of a thin solenoid with a homogeneous magnetic field of 1 Tesla inside. The inner volume is instrumented with a silicon tracker reaching a maximum detectable rigidity of 100 TV and a calorimeter system that is 70 radiation lengths deep, equivalent to four nuclear interaction lengths, which extends the energy reach for cosmic-ray nuclei up to the PeV scale, i.e. beyond the cosmic-ray knee. In conclusion, covering most of the sky continuously, AMS-100 will detect high-energy gamma-rays in the calorimeter system and by pair conversion in the thin solenoid, reconstructed with excellent angular resolution in the silicon tracker.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

AC loss and contact resistance in REBCO CORC ® , Roebel, and stacked tape cables

Abstract Many high-temperature superconductor (HTS) applications require superconducting cables with high currents while operating in an alternating magnetic field. HTS cables should be composed of numerous superconducting tapes to achieve the required current capacity. Alternating current and magnetic fields cause AC losses in such cables and can provoke conductor instability. AC losses and contact resistances were measured of several cable designs based on commercially available REBCO tapes at the University of Twente. The AC loss was measured under identical conditions for eight REBCO conductors manufactured according to three types of cabling methods—CORC ® (Conductor on Round Core), Roebel, and stacked tape, including a full-size REBCO CICC (cable in conduit conductor). The measurements were done at T = 4.2 K without transport current in a sinusoidal AC magnetic field of 0.4 T amplitude and frequencies from 5 to 55 mHz. The AC loss was measured simultaneously by calibrated gas flow calorimeter utilizing the helium boil-off method and by the magnetization method using pick-up coils. Also, the AC loss of two CORC® conductors and a Roebel cable was measured at 77 K. Each conductor was measured with and without background field of 1 T. The measured AC coupling loss in the CORC ® and Roebel conductors is negligible at 4.2 K for the applied conditions while at 77 K coupling loss was observed for all conductors. The absence of coupling loss at 4.2 K can be explained by shielding of the conductor interior; this is confirmed with measurement and calculation of the penetration field of CORC ® and Roebel cables. The inter-tape contact resistance was measured for CORC ® and stacked tape samples at 4.2 and 77 K. It was demonstrated that a short heat treatment of CORC ® conductor with solder-coated tapes activates tape-to-tape soldering and decreases the contact resistance. The reduction of contact resistance by two orders in magnitude to tens of nΩm is comparable with the interstrand contact resistance in ITER Nb 3 Sn type conductors.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗