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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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264 records · Page 15

Energy Efficient Legged Robotics at Sandia Labs, Part 2

Sandia is developing energy efficient actuation and drive train technologies to dramatically improve the charge life of legged robots. The work is supported by DARPA, and Sandia will demonstrate an energy efficient bipedal robot at the technology exposition section of the DARPA Robotics Challenge Finals in June, 2015. This video, the second in a series, describes the continued development and integration of the Sandia Transmission Efficient Prototype Promoting Research (STEPPR) robot.

42 ENGINEERING↗

Finite Energy and Bounded Actuator Attacks on Cyber-Physical Systems

As control system networks are being connected to enterprise level networks for remote monitoring, operation, and system-wide performance optimization, these same connections are providing vulnerabilities that can be exploited by malicious actors for attack, financial gain, and theft of intellectual property. Much effort in cyber-physical system (CPS) protection has focused on protecting the borders of the system through traditional information security techniques. Less effort has been applied to the protection of cyber-physical systems from intelligent attacks launched after an attacker has defeated the information security protections to gain access to the control system. In this paper, attacks on actuator signals are analyzed from a system theoretic context. The threat surface is classified into finite energy and bounded attacks. These two broad classes encompass a large range of potential attacks. The effect of theses attacks on a linear quadratic (LQ) control are analyzed, and the optimal actuator attacks for both finite and infinite horizon LQ control are derived, therefore the worst case attack signals are obtained. The closed-loop system under the optimal attack signals is given and a numerical example illustrating the effect of an optimal bounded attack is provided.

Djouadi, Seddik M↗

An Assessment of U.S.-Based Electron-Ion Collider Science

The Committee on U.S.-Based Electron-Ion Collider Science Assessment was asked by the Department of Energy (DOE), in its statement of task, to assess the scientific justification for a U.S. domestic electron-ion collider (EIC) facility and to evaluate the importance and urgency of the science that an EIC would address to both nuclear science and the physical sciences more broadly. The committee’s task also included assessing the role of an EIC in the global context, including its relationship to other facilities within the United States and around the world. Lastly, the committee was asked to assess the broader impacts of an EIC, including on U.S. science leadership. The full statement of task is included in Appendix A. In summary, the committee finds a compelling scientific case for such a facility. The science questions that an EIC will answer are central to completing an understanding of atoms as well as being integral to the agenda of nuclear physics today. In addition, the development of an EIC would advance accelerator science and technology in nuclear science; it would also benefit other fields of accelerator-based science and society, from medicine through materials science to elementary particle physics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

REBCO -- a silver bullet for our next high-field magnet and collider budget?

High-field superconducting magnets with a dipole field of 16 T and above enable future energy-frontier circular particle colliders. Although we believe these magnets can be built, none exists today. They can also be a showstopper for future high-energy machines due to a prohibitively high price tag based on the current conductor and magnet fabrication cost. The high-temperature superconducting REBCO coated conductor can address both the technical and cost issues, a silver bullet to lay both monsters to rest. The challenges and unknowns, however, can be too arduous to make the silver bullet. We lay out a potential road forward and suggest key action items. As a contribution from the accelerator community, we attempt to clarify for our theorist and experimenter colleagues a few aspects about the future high-field superconducting magnets. We hope to stimulate an effective plan for the 2023 P5 process that can lead to a cost-effective high-field magnet technology for future colliders and the exciting physics they can steward.

43 PARTICLE ACCELERATORS↗

Simple coplanar waveguide resonator mask targeting metal-substrate interface

This white paper presents a single-layer mask, found at https://github.com/Boulder-Cryogenic-Quantum-Testbed/simple-resonator-mask. It is designed for fabrication of superconducting microwave resonators towards 1:1 comparisons of dielectric losses from the metal-substrate interface. Finite-element electromagnetic simulations are used to determine participation ratios of the four major regions of the on-chip devices, as well as to confirm lack of crosstalk between neighboring devices and demonstrate coupling tunability over three orders of magnitude. This mask is intended as an open-source community resource for facilitating precise and accurate comparisons of materials in the single-photon, millikelvin regime.

Kopas, Cameron J.↗

Highly tunable, inexpensive and easily fabricated magnetocaloric materials

A method is provided of making a magnetocaloric alloy composition comprising Ni, Co, Mn, and Ti, which preferably includes certain beneficial substitutional elements, by melting the composition and rapidly solidifying the melted composition at a cooling rate of at least 100 K/second (Kelvin/second) to improve a magnetocaloric property of the composition. The rapidly solidified composition can be heat treated to homogenize the composition and annealed to tune the magneto-structural transition for use in a regenerator.

Bez, Henrique Neves↗

Round superconductor wires

A round superconductor wire and method for fabricating same are disclosed. Embodiments are directed to a round superconductor wire including at least two superconductor tapes wound on a wire former. Each superconductor tape includes: bottom stabilizer and silver layers; substrate disposed above the bottom silver layer; buffer film stack disposed above the substrate; superconductor film disposed above the buffer film stack; top silver layer disposed above the superconductor film; and top stabilizer layer disposed above the top silver layer. At least one of the bottom stabilizer layer, bottom silver layer, substrate, buffer film stack, superconductor film, top silver layer, or top stabilizer layer is of a different width, thickness, or material composition in one of the superconductor tapes than in another of the superconductor tapes. These and other embodiments achieve a round superconductor wire having improved current density in high magnetic field applications when made in small diameters.

Majkic, Goran↗