Calculating the Test Uncertainty of the LANL Filter Test System for Nuclear Storage Containers
No abstract provided.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
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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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RGA Analysis of Plasma Cleaned Vacuum Systems [Slides]
The goal of this project was to qualitatively evaluate the efficacy of using plasma cleaning to remove PDMS from vacuum systems. Silicon containing compounds are notorious for interfering with vacuum system techniques such as x-ray photoelectron spectroscopy (XPS), Auger Electron Spectroscopy (AES) and Secondary lon Mass Spectrometry (SIMS). Finding a way to remotely and rapidly remove contaminants from a system saves time and money for analysts using vacuum analytical techniques.
42 ENGINEERING↗
Investigation of image enhancement techniques for the development of a self-contained airborne radar navigation system
This study was devoted to an investigation of the feasibility of applying advanced image processing techniques to enhance radar image characteristics that are pertinent to the pilot's navigation and guidance task. Millimeter (95 GHz) wave radar images for the overwater (i.e., offshore oil rigs) and overland (Heliport) scenario were used as a data base. The purpose of the study was to determine the applicability of image enhancement and scene analysis algorithms to detect and improve target characteristics (i.e., manmade objects such as buildings, parking lots, cars, roads, helicopters, towers, landing pads, etc.) that would be helpful to the pilot in determining his own position/orientation with respect to the outside world and assist him in the navigation task. Results of this study show that significant improvements in the raw radar image may be obtained using two dimensional image processing algorithms. In the overwater case, it is possible to remove the ocean clutter by thresholding the image data, and furthermore to extract the target boundary as well as the tower and catwalk locations using noise cleaning (e.g., median filter) and edge detection (e.g., Sobel operator) algorithms.
Phatak, A. V.↗
An expert system based intelligent control scheme for space bioreactors
An expert system based intelligent control scheme is being developed for the effective control and full automation of bioreactor systems in space. The scheme developed will have the capability to capture information from various resources including heuristic information from process researchers and operators. The knowledge base of the expert system should contain enough expertise to perform on-line system identification and thus be able to adapt the controllers accordingly with minimal human supervision.
San, Ka-Yiu↗
Future SAR Imaging Systems: Goals, Plans, Challenges and Opportunities
Synthetic Aperture Radar (SAR) Earth observation data are becoming increasingly ubiquitous as new spaceborne systems become operational and their data are made available to scientists and applications users. The characteristic of active sensors like SAR to be able to observe Earth independent of weather or solar illumination, coupled with regular data acquisition, fosters reliability and encourages the investment in algorithm and product development toward a beneficial result. As SAR systems typically contain proprietary or nationally important technologies, civilian SAR systems are typically developed with a national focus, or in the case of the European Union, with the Union’s focus. As a result, when viewed from a global perspective, SAR programs can be generally viewed as independent developments, each with their own requirements, schedules, development approaches, and data policies. At the same time, these systems can be expensive, and particularly in an era of increasingly open data policies, coordination of programs could reduce redundancy in observations, increase sampling density and measurement diversity, and improve dependability of data streams in the long term. Since 2018, agency representatives from NASA, ESA, DLR, JAXA, ISRO, ASI, and CONAE have been evaluating the possibilities for programmatic and technical coordination of future SAR systems, data sharing, and scientific exploitation. In this paper, we describe the work in discovering trends and possibilities associated with flight systems, by evaluating current and future plans for SAR systems around the world, and identifying opportunities for coordination.
Zink, Manfred↗
Methanosarcina acetivorans contains a functional ISC system for iron-sulfur cluster biogenesis
Explore the source record for details and available documents.
Thomas M. Deere↗
Fuel cell components and systems having carbon-containing electrically-conductive hollow fibers
A method, according to one embodiment, includes acquiring a structure having an ionically-conductive, electrically-resistive electrolyte/separator layer covering an inner or outer surface of a carbon-containing electrically-conductive hollow fiber and a catalyst along one side thereof, adding an anode that extends along at least part of a length of the structure, and adding a cathode that extends along at least part of the length of the structure, the cathode being on an opposite side of the hollow fiber as the anode.
25 ENERGY STORAGE↗
A New Empirical Correlation for Condensation Heat Transfer Coefficient of Air-Steam Mixture on a Vertical Tube
The Passive Containment Cooling System (PCCS) provides passive means to remove the decay heat and protect the integrity of the containment during severe accidents. For thermal design and performance evaluation of the PCCS condensers, one needs experimental data and a heat transfer model for condensation heat transfer in the presence of a noncondensable gas on a vertical tube. The main objective of this study is to propose a new empirical correlation, based on the experimental data obtained in Jeju National University, expressed in terms of dimensionless numbers. Dimensionless numbers to account for vapor-gas condensation phenomena are found by non-dimensionalizing the governing boundary layer equations, and the predictions of the proposed correlation is validated with selected sets of experimental data. (authors)
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Research and technology, 1990
Selected research and technology activities at Ames Research Center, including the Moffett Field site and the Dryden Flight Research Facility, are summarized. These accomplishments exemplify the Center's varied and highly productive research efforts for 1990. The activities addressed are under the directories of: (1) aerospace systems which contains aircraft technology, full-scale aerodynamics research, information sciences, aerospace human factors research, and flight systems and simulation research divisions; (2) Dryden flight research facility which contains research engineering division; (3) aerophysics which contains aerodynamics, fluid dynamics, and thermosciences divisions; and (4) space research which contains advanced life support, space projects, earth system science, life science, and space science divisions, and search for extraterrestrial intelligence and space life sciences payloads offices.
Source record↗
Radio Frequency Trap for Containment of Plasmas in Antimatter Propulsion Systems Using Rotating Wall Electric Fields
A containment apparatus for containing a cloud of charged particles comprises a cylindrical vacuum chamber having a longitudinal axis. Within the vacuum chamber is a containment region. A magnetic field is aligned with the longitudinal axis of the vacuum chamber. The magnetic field is time invariant and uniform in strength over the containment region. An electric field is also aligned with the longitudinal axis of the vacuum chamber and the magnetic field. The electric field is time invariant, and forms a potential well over the containment region. One or more means are disposed around the cloud of particles for inducing a rotating electric field internal to the vacuum chamber. The rotating electric field imparts energy to the charged particles within the containment region and compress the cloud of particles. The means disposed around the outer surface of the vacuum chamber for inducing a rotating electric field are four or more segments forming a segmented ring, the segments conforming to the outer surface of the vacuum chamber. Each of the segments is energized by a separate alternating voltage. The sum of the voltages imposed on each segment establishes the rotating field. When four segments form a ring, the rotating field is obtained by a signal generator applying a sinusoidal signal phase delayed by 90,180 and 270 degrees in sequence to the four segments.
Sims, William Herbert, III↗
Boron injection system for controlling a nuclear reaction by delivering boron into a containment vessel
A nuclear power system includes a reactor vessel that includes a reactor core mounted within a volume of the reactor vessel. The reactor core includes one or more nuclear fuel assemblies configured to generate a nuclear fission reaction. The nuclear power system further includes a containment vessel sized to enclose the reactor vessel such that an open volume is defined between the containment vessel and the reactor vessel. A boron injection system is positioned in the open volume of the containment vessel and includes an amount of boron sufficient to stop the nuclear fission reaction or maintain the nuclear fission reaction at a sub-critical state. The boron injection system is positioned to deliver the amount of boron into the open volume.
Linik, Larry↗
Self-Contained Avionics Sensing and Flight Control System for Small Unmanned Aerial Vehicle
A self-contained avionics sensing and flight control system is provided for an unmanned aerial vehicle (UAV). The system includes sensors for sensing flight control parameters and surveillance parameters, and a Global Positioning System (GPS) receiver. Flight control parameters and location signals are processed to generate flight control signals. A Field Programmable Gate Array (FPGA) is configured to provide a look-up table storing sets of values with each set being associated with a servo mechanism mounted on the UAV and with each value in each set indicating a unique duty cycle for the servo mechanism associated therewith. Each value in each set is further indexed to a bit position indicative of a unique percentage of a maximum duty cycle for the servo mechanism associated therewith. The FPGA is further configured to provide a plurality of pulse width modulation (PWM) generators coupled to the look-up table. Each PWM generator is associated with and adapted to be coupled to one of the servo mechanisms.
Shams, Qamar A.↗
Apptainer Without Setuid
Apptainer (formerly known as Singularity) since its beginning implemented many of its container features with the assistance of a setuid-root program. It still supports that mode, but as of version 1.1.0 it no longer uses setuid by default. This is feasible because it now can mount squash filesystems, mount ext2/3/4 filesystems, and use overlayfs using unprivileged user namespaces and FUSE. It also now enables unprivileged users to build containers, even without requiring system administrators to configure /etc/subuid and /etc/subgid unlike other "rootless" container systems. As a result, all the unprivileged functions can be used nested inside of another container, even if the container runtime prevents any elevated privileges.
Dykstra, Dave↗
Thermodynamic description of the Ti-Mo-Nb-Ta-Zr system and its implications for phase stability of Ti bio-implant materials
Titanium alloys are great candidates for applications such as biomedical implants that require biocompatibility, a low Young's modulus and a high strength. However, the properties of Ti alloys are highly dependent on phase stability. Here in the present work, a database for the Ti-Mo-Nb-Ta-Zr system has been evaluated using the CALPHAD (CALculation of PHAse Diagram) approach. The database was completed by evaluating the accuracy of previously modeled systems from literature and modeling systems that, to the best of the authors’ knowledge, had no modeling available in literature. All of the binary systems that make up the Ti-Mo-Nb-Ta-Zr system had previously modeled thermodynamic descriptions available in the literature and in most cases had multiple different descriptions available, which meant determining which previous thermodynamic description most accurately modeled the binary system with a direct focus on the bcc phase. In order to determine the accuracy of the multiple available thermodynamic descriptions from literature a combination of experimental data (also obtained from the literature) and computed thermochemical properties of the bcc phase from DFT (Density Functional Theory)-based first-principles calculations (present work) were used. Once the thermodynamic descriptions for the binary systems were chosen, focus shifted to the Ti-containing ternary systems. The Ti-Mo-Zr, Ti-Nb-Zr and Ti-Ta-Zr systems had previous thermodynamic description available in literature, which were incorporated without changes into the working database. The Ti-Mo-Ta, Ti-Nb-Ta and Ti-Mo-Nb systems had, to the authors’ knowledge, no descriptions available in the literature. Interaction parameters were determined for the Ti-Mo-Ta and Ti-Nb-Ta systems, and no interaction parameters were introduced for the Ti-Mo-Nb system. The database introduced by this work satisfactorily predicts the thermodynamics of the Ti-Mo-Nb-Ta-Zr system.
CALculation of PHAse Diagrams↗
Pre- and post-launch operation of the Resolve soft X-ray spectrometer onboard the XRISM satellite
Resolve is a high-resolution X-ray spectrometer onboard the X-Ray Imaging and Spectroscopy Mission (XRISM), launched on September 6 (UT), 2023. The Resolve has performed better than its required spectral resolution (7 eV at full width at half maximum at 6 keV), both on the ground and in orbit, and has been confirmed to have comparable performance to the soft X-ray spectrometer onboard the ASTRO-H (Hitomi) satellite. The focal plane is composed of an array of microcalorimeter detectors operated at 50 mK to achieve the required energy resolution, and the cooling system is designed to satisfy the lifetime requirement of over 3 years. The focal plane and cooling system are contained in a vacuum-insulated dewar. The cooling system is equipped with a two-stage adiabatic demagnetization refrigerator (ADR) that uses superfluid liquid helium (LHe) as its heat sink. The system includes a third ADR stage that can be used to provide the heat sink when the helium is exhausted. A Joule–Thomson cooler and several two-stage Stirling coolers are used to reduce the heat load on the LHe. During pre-launch operations, we carried out a superfluid LHe top-off operation. The resultant amount of LHe onboard Resolve was over 35 L before launch, which is sufficient to meet the lifetime requirement. During post-launch operation, the LHe vent valve was opened 5 min after launch during rocket acceleration, and the cryocoolers were turned on after several orbits, as planned, which established stable cooling within the dewar. Pre- and post-launch operations for the Resolve instrument were planned around multiple constraints from launch vehicle operations; all were successfully completed, and the launch requirements were fully met.
X-Ray Imaging and Spectroscopy Mission↗
Ultrareliable, fault-tolerant control systems: A conceptual description
An Ultrareliable, Fault-Tolerant, Control-System (UFTCS) concept is described using a systems design philosophy which allows development of system structures containing virtually no common elements. Common elements limit achievable system reliability and can cause catastrophic loss of fault-tolerant system function. The UFTCS concept provides the means for removing common system elements by permitting the elements of the system to operate as independent, uncoupled entities. Multiple versions of the application program are run on dissimilar hardware. Fault tolerance is achieved through the use of static redundancy management.
Webster, L. D.↗
Dusty debris clouds around main sequence and post-main sequence stars
During the past decade, infrared observations by IRAS and from the ground have revealed that many stars are orbited by dusty debris disks. Somewhat more indirect arguments indicate that many of these systems also contain asteroids, comets, and/or planets, thereby suggesting that planetary systems may be quite common in the Milky Way. Dust clouds at the main sequence K5 star HD 98800 and the white dwarf Giclas 29-38 are particularly noteworthy and mysterious.
Zuckerman, B.↗