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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 109 records · Page 6

GPU Lifetimes on Titan Supercomputer: Survival Analysis and Reliability

The Cray XK7 Titan was the top supercomputer system in the world for a long time and remained critically important throughout its nearly seven year life. It was an interesting machine from a reliability viewpoint as most of its power came from 18,688 GPUs whose operation was forced to execute three rework cycles, two on the GPU mechanical assembly and one on the GPU circuitboards. We write about the last rework cycle and a reliability analysis of over 100,000 years of GPU lifetimes during Titan’s 6-year-long productive period. Using time between failures analysis and statistical survival analysis techniques, we find that GPU reliability is dependent on heat dissipation to an extent that strongly correlates with detailed nuances of the cooling architecture and job scheduling. We describe the history, data collection, cleaning, and analysis and give recommendations for future supercomputing systems. We make the data and our analysis codes publicly available.

Ostrouchov, George↗

Alignment of the ATLAS Inner Detector in Run 2

The performance of the ATLAS Inner Detector alignment has been studied using pp collision data at s√=13TeV collected by the ATLAS experiment during Run 2 (2015–2018) of the Large Hadron Collider (LHC). The goal of the detector alignment is to determine the detector geometry as accurately as possible and correct for time-dependent movements. The Inner Detector alignment is based on the minimization of track-hit residuals in a sequence of hierarchical levels, from global mechanical assembly structures to local sensors. Subsequent levels have increasing numbers of degrees of freedom; in total there are almost 750,000. The alignment determines detector geometry on both short and long timescales, where short timescales describe movements within an LHC fill. The performance and possible track parameter biases originating from systematic detector deformations are evaluated. Momentum biases are studied using resonances decaying to muons or to electrons. The residual sagitta bias and momentum scale bias after alignment are reduced to less than ~0.1 TeV -1 and 0.9×10 -3 , respectively. Impact parameter biases are also evaluated using tracks within jets.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Eligibility Assessment of TA-52-1 and TA-52-11: The Ultra-High Temperature Reactor Experiment (UHTREX) Complex

The U.S. Department of Energy (DOE), National Nuclear Security Administration, Los Alamos Field Office (NA-LA) requests the State Historic Preservation Officer (SHPO) to concur with the eligibility determinations contained in this report for Buildings 1 and 11 in Technical Area 52 (TA-52) at Los Alamos National Laboratory (LANL or the Laboratory). Triad National Security LLC cultural resources staff have completed the evaluation of two buildings, called the UHTREX Complex, for inclusion in the National Register of Historic Places (Register). This complex includes the UHTREX Reactor Building (TA-52-1), and an associated Mechanical Assembly Building (TA-52-11). As part of LANL’s Footprint Reduction Program, both facilities of the UHTREX Complex are scheduled for characterization and demolition. In addition to evaluating their eligibility in the Register, the properties at TA-52 were assessed for potential adaptive reuse, long-term preservation, and public interpretation. Based on the findings in this assessment report, both TA-52-1 and TA-52-11 have been determined to not be eligible for inclusion in the Register. The history of the UHTREX Complex lacks association with exceptionally significant Cold War events of scientific developments. Both TA-52-1 and TA-52-11 lack the necessary internal historic integrity suitable for long-term preservation or public interpretation. And both facilities contain legacy radioactive contamination, which prohibits their reuse. In addition to its loss of integrity and context, TA-52- 11 has been determined ineligible due to its status as a support building of secondary or minor importance. In compliance with Section 106 and Section 110 of the National Historic Preservation Act of 1966, as amended, and with the Programmatic Agreement among the U.S. Department of Energy, National Nuclear Security Administration, Los Alamos Field Office, the New Mexico State Historic Preservation Office, and the Advisory Council on Historic Preservation Concerning Management of the Historic Properties at Los Alamos National Laboratory, Los Alamos, New Mexico, the SHPO is requested to concur with the eligibility determinations contained in this report for the UHTREX Complex in TA-52.

99 GENERAL AND MISCELLANEOUS↗

Electron transport across the cell envelope via multiheme c -type cytochromes in Geobacter sulfurreducens

Extracellular electron transfer (EET) enables certain microorganisms to respire using soluble and insoluble extracellular electron acceptors by transporting electrons across the cell envelope. Among these, G. sulfurreducens serves as a model organism for understanding direct EET pathways, where multiheme c-type cytochromes mediate electron transport from intracellular redox carriers to extracellular acceptors such as Fe(III) oxides and electrodes. This review focuses on heme-dependent electron transfer in Geobacter sulfurreducens, detailing the roles of inner membrane cytochromes, periplasmic carriers, outer membrane conduits, and recently characterized extracellular nanowires formed by polymerized multiheme c-type cytochromes, including OmcS, OmcE, and OmcZ. We examine the state of understanding of their physiological function, their structural features, expression patterns, and essentiality under various respiratory conditions. These insights advance our understanding of microbial anaerobic respiration and have implications for biogeochemical cycling, bioenergy generation, and bioremediation. The molecular architecture, assembly mechanisms, and secretion pathways of multiheme c-type cytochrome nanowires remain active areas of investigation, offering promising directions for future research and biotechnological innovation in engineered microbial systems.

Chemistry↗

Flexible solar-array mechanism

One of the key elements of the flexible rolled-up solar array system is a mechanism to deploy, retract, and store the flexible solar-cell arrays. The selection of components, the design of the mechanism assembly, and the tests that were performed are discussed. During 6 months in orbit, all mission objectives were satisfied, and inflight performance has shown good correlation with preflight analyses and tests.

Olson, M. C.↗

Momentum wheel with magnetic bearings

An engineering model of a momentum wheel is described that is suspended by magnetic bearings. It consists of a mechanical assembly on the right, and associated electronics on the left. The momentum wheel is mounted at the center of the rotor shaft and the magnetic bearings are on each end. The rotor is magnetically suspended so there is no physical contact between the rotor and the support structure. The system, therefore, can operate directly in the vacuum environment without lubrication; and it has virtually unlimited operating lifetime, independent of speed.

Veillette, L. J.↗

Prospective areas in the production technology of scientific equipment for space research

The average labor of individual types of operations in the percentage ratio of the total labor consumption of manufacturing scientific instruments and apparatus for space research is presented. The prospective areas in the production technology of billet, machining, mechanical assembly, installation and assembly, adjustment and regulation and testing and control operations are noted. Basic recommendations are made with respect to further reduction of labor consumption and an increase in the productivity of labor when manufacturing scientific equipment for space research.

Breslavets, A. V.↗

Design study for Thermal Infrared Multispectral Scanner (TIMS)

The feasibility of dividing the 8-12 micrometer thermal infrared wavelength region into six spectral bands by an airborne line scanner system was investigated. By combining an existing scanner design with a 6 band spectrometer, a system for the remote sensing of Earth resources was developed. The elements in the spectrometer include an off axis reflective collimator, a reflective diffraction grating, a triplet germanium imaging lens, a photoconductive mercury cadmium telluride sensor array, and the mechanical assembly to hold these parts and maintain their optical alignment across a broad temperature range. The existing scanner design was modified to accept the new spectrometer and two field filling thermal reference sources.

Stanich, C. G.↗

Design and development of an optical scanning mechanism (OSMA) with minimum momentum transfer

The development model for an optical scanning mechanism assembly is described as being two equal inertial masses which collide with each other to minimize the momentum transfer to the satellite and other mounted instruments. The design criteria for the mirror, the compensating inertia structure and other components are given. The details of the design are discussed and related test results are presented, which show the validity of the design concept for momentum compensation.

Sainz, L. B. F.↗

Materials processing in Space/Spacelab. FES/VCGS payload critical design review

A 25 mW He-Ne laser holographic recorder for recording the solution growth of triglycine sulfate crystals under low-zero gravity conditions is described. A systems engineering and design analysis, and mechanical and electrical design analyses of the equipmentation are presented. The equipment, fabricated for the Sl-3 flight on the space shuttle, was designed to take 300 holograms (two orthogonal views) on 50-235 film of each growth experiment. Specifications and capabilities for support module mechanical assemblies are lso presented.

Source record↗

Requirements and design of the graphite/epoxy structural elements for the optical telescope assembly of the space telescope

The production of the Space Telescope's Metering Truss Structure (MTS) and Focal Plane Structure (FPS), which are of graphite/epoxy, is described. Graphite/epoxy laminates were chosen because of their high strength and stiffness, low weight, and a controlled coefficient of thermal expansion approaching zero. Photocopy masters, which are dimensionally accurate and stable photographic reproductions of full size engineering drawings, allowed the exact assembly of bonded or bolted parts by assembly mechanics, cutting costs and speeding production. While moisture absorption, high through-the-thickness coefficient of thermal expansion effects, and labor-intensive layup costs are potentially problematic in some cases, it is expected that solutions can be found through analytical and developmental programs.

Golden, C. T.↗

Deployable controllable geometry truss beam

A study was conducted on a truss beam structural concept that can deploy and maneuver in a serpentine manner to align or position the truss beam tip. The truss beam is composed of a series of rod members connected together at joints that provide the required rotational degrees of freedom. The current study was conducted to evaluate the requirements of the joints and define a mechanical assembly that could provide both high structural stiffness and the required maneuverability. The truss beam requires two joint types; both types were fabricated and incorporated in a demonstration model. An analysis of the concept was performed to define the location and orientation of the beam tip during deployment and serpentine maneuvers.

Rhodes, M. D.↗

Large space reflector technology on the Space Station

This paper discusses the role of the Space Station in the evolutionary development of large space reflector technology and the accommodation of mission systems which will apply large space reflectors during the late 1990s and the early part of the next century. Reflectors which range from 10 to 100 meters in size and which span the electromagnetic spectrum for applications that include earth communications, earth observations, astrophysics and solar physics, and deep space communications are discussed. The role of the Space Station in large space reflector technology development and system performance demonstration is found to be critical; that role involves the accommodation of a wide variety of technology demonstrations and operational activities on the Station, including reflector deployment and/or assembly, mechanical performance verification and configuration refinement, systematic diagnostics of reflector surfaces, structural dynamics and controls research, overall system performance characterization and modification (including both radio frequency field pattern measurements and required end-to-end system demonstrations), and reflector-to-spacecraft integration and staging. A unique facility for Space Station-based, large space reflector research and development is proposed. A preliminary concept for such a Space Station-based Large Space Reflector Facility (LSRF) is described.

Mankins, J. C.↗

Spot Paint Sprayer

Proposed atomizing system applies paint to small areas or objects - typically nuts, bolts, or other fasteners on flat surfaces. System used in electronic and mechanical assemblies, where small parts coated but not reached by normal spraying techniques. Coverage expected more complete than that obtained by hand brushing. Paint applicator contains two chambers in which flow of air and atomized paint controlled to ensure complete coating of fastener. In electrostatic version, inner tube serves as one electrode, while object coated serves as other electrode.

Leifsen, J. Arthur↗

Imaging characteristics of the Extreme Ultraviolet Explorer microchannel plate detectors

The Extreme Ultraviolet Explorer (EUVE) satellite will conduct an all-sky survey over the wavelength range from 70 A to 760 A using four grazing-incidence telescopes and seven microchannel-plate (MCP) detectors. The imaging photon-counting MCP detectors have active areas of 19.6 cm2. Photon arrival position is determined using a wedge-and-strip anode and associated pulse-encoding electronics. The imaging characteristics of the EUVE flight detectors are presented including image distortion, flat-field response, and spatial differential nonlinearity. Also included is a detailed discussion of image distortions due to the detector mechanical assembly, the wedge-and-strip anode, and the electronics. Model predictions of these distortions are compared to preflight calibration images which show distortions less than 1.3 percent rms of the detector diameter of 50 mm before correction. The plans for correcting these residual detector image distortions to less than 0.1 percent rms are also presented.

Vallerga, J. V.↗

Intelligent control and adaptive systems; Proceedings of the Meeting, Philadelphia, PA, Nov. 7, 8, 1989

Various papers on intelligent control and adaptive systems are presented. Individual topics addressed include: control architecture for a Mars walking vehicle, representation for error detection and recovery in robot task plans, real-time operating system for robots, execution monitoring of a mobile robot system, statistical mechanics models for motion and force planning, global kinematics for manipulator planning and control, exploration of unknown mechanical assemblies through manipulation, low-level representations for robot vision, harmonic functions for robot path construction, simulation of dual behavior of an autonomous system. Also discussed are: control framework for hand-arm coordination, neural network approach to multivehicle navigation, electronic neural networks for global optimization, neural network for L1 norm linear regression, planning for assembly with robot hands, neural networks in dynamical systems, control design with iterative learning, improved fuzzy process control of spacecraft autonomous rendezvous using a genetic algorithm.

Rodriguez, Guillermo↗

A PARC system for terminal docking

A Panoramic viewing system for Automated Rendezvous and Capture (PARC) has been proposed as a visual information feedback system for terminal docking/berthing. The system relies on a unique Panoramic Annular Lens (PAL) which captures an image of its surroundings in real time. This paper describes the evolution of the PAL along with technical details of its imaging capabilities. Several examples are given of radial metrology, where PAL imaging systems are used to perform visual inspections and measurements. Digital image acquisition and processing techniques, used to interpret various features appearing in the images and to transform images for improved human viewing, are also included. These discussions are followed by a potential application for PARC involving berthing of active and passive mechanical assemblies associated with Space Station Freedom.

Gilbert, John A.↗