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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
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

International Space Station (ISS) Major Constituent Analyzer (MCA) On-Orbit Performance

The Major Constituent Analyzer (MCA) is an essential part of the International Space Station (ISS) environmental control and life support system. The analyzer provides continuous readout of the partial pressures of six gases, nitrogen (N2), oxygen (O2), hydrogen (H2), carbon dioxide (CO2), methane (CH4) and water vapor (H2O) in the various ISS US. on-orbit modules. Continuous readout of the partial pressures of these gases is critical to verifying safe operation of the Atmosphere Revitalization (AR) system, Atmosphere Control System (ACS), and crew safety for Airlock Extravehicular Activities (EVAs). The MCA encountered some operational interruptions since being launched to orbit on Flight 5A in February 2001. Electronic, software, and hardware modifications and on-orbit crew maintenance of the MCA were necessary to restore its capability. This paper describes the modifications and the on-orbit maintenance performed to return the MCA to operational status, including brief explanations of the MCA failures and the associated hardware and electronic modifications. Operational procedures that were required to return the MCA to operational status, and the more recent successes of supporting both Russian and U.S. ISS EVA preparations, are also discussed

Reysa, Richard↗
NASA NTRS2005

Designing Flight Deck Procedures

Three reports address the design of flight-deck procedures and various aspects of human interaction with cockpit systems that have direct impact on flight safety. One report, On the Typography of Flight- Deck Documentation, discusses basic research about typography and the kind of information needed by designers of flight deck documentation. Flight crews reading poorly designed documentation may easily overlook a crucial item on the checklist. The report surveys and summarizes the available literature regarding the design and typographical aspects of printed material. It focuses on typographical factors such as proper typefaces, character height, use of lower- and upper-case characters, line length, and spacing. Graphical aspects such as layout, color coding, fonts, and character contrast are discussed; and several cockpit conditions such as lighting levels and glare are addressed, as well as usage factors such as angular alignment, paper quality, and colors. Most of the insights and recommendations discussed in this report are transferable to paperless cockpit systems of the future and computer-based procedure displays (e.g., "electronic flight bag") in aerospace systems and similar systems that are used in other industries such as medical, nuclear systems, maritime operations, and military systems.

Degani, Asaf↗
NASA NTRS2013

Advanced Caution and Warning System, Final Report - 2011

The work described in this report is a continuation of the ACAWS work funded in fiscal year (FY) 2010 under the Exploration Technology Development Program (ETDP), Integrated Systems Health Management (ISHM) project. In FY 2010, we developed requirements for an ACAWS system and vetted the requirements with potential users via a concept demonstration system. In FY 2011, we developed a working prototype of aspects of that concept, with placeholders for technologies to be fully developed in future phases of the project. The objective is to develop general capability to assist operators with system health monitoring and failure diagnosis. Moreover, ACAWS was integrated with the Discrete Controls (DC) task of the Autonomous Systems and Avionics (ASA) project. The primary objective of DC is to demonstrate an electronic and interactive procedure display environment and multiple levels of automation (automatic execution by computer, execution by computer if the operator consents, and manual execution by the operator).

Spirkovska, Lilly↗
NASA NTRS1988

Investigations on the usefulness of the Massively Parallel Processor for study of electronic properties of atomic and condensed matter systems

The usefulness of the Massively Parallel Processor (MPP) for investigation of electronic structures and hyperfine properties of atomic and condensed matter systems was explored. The major effort was directed towards the preparation of algorithms for parallelization of the computational procedure being used on serial computers for electronic structure calculations in condensed matter systems. Detailed descriptions of investigations and results are reported, including MPP adaptation of self-consistent charge extended Hueckel (SCCEH) procedure, MPP adaptation of the first-principles Hartree-Fock cluster procedure for electronic structures of large molecules and solid state systems, and MPP adaptation of the many-body procedure for atomic systems.

Das, T. P.↗
DOE OSTI2025

The separatrix electron density in JET, ASDEX upgrade and alcator C-Mod H-mode plasmas: A common evaluation procedure and correlation with engineering parameters

The separatrix electron density is an important parameter for core-edge scenario integration in tokamak devices, as it influences plasma confinement, divertor detachment and disruption avoidance. This quantity has been measured in H-mode discharges on JET, ASDEX Upgrade and Alcator C-Mod by applying the same fitting function to Thomson scattering measurements, and by employing the same analysis technique based on scrape-off layer power balance. To estimate the power crossing the separatrix, the inter-ELM time derivative of the plasma energy d W /d t has been experimentally evaluated and found to be approximately a constant fraction of the absorbed heating power. Correlations between n e,sep and engineering parameters have been investigated, revealing that n e,sep scales with the divertor neutral pressure p 0,div in a similar manner across all devices. Additionally, when n e,sep is normalized to the obtained n e,sep dependency, no clear correlation with the plasma current is found. These observations are in agreement with the 2-point model, which suggests that the upstream separatrix density is mainly set by the recycling at the divertor target.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1978

CV 990 interface test and procedure analysis of the monkey restraint, support equipment, and telemetry electronics proposed for Spacelab

A biological system proposed to restrain a monkey in the Spacelab was tested under operational conditions using typical metabolic and telemetered cardiovascular instrumentation. Instrumentation, interfaced with other electronics, and data gathering during a very active operational mission were analyzed for adequacy of procedure and success of data handling by the onboard computer.

Newsom, B. D.↗
NASA NTRS1985

Total electron scattering cross sections. I - He, Ne, Ar, Xe

The apparatus and experimental procedures used to obtain total electron scattering cross sections are described, and results are presented for He, Ne, Ar and Xe in the 4-300 eV incident energy range, together with statistical errors. The results are generally found to be in good agreement with previous data except at low impact energies. Serious discrepancies remain in Xe below 20 eV impact energy.

Nickel, J. C.↗
NASA NTRS1983

Practical preventive reliability using matrix forms

This paper describes a practical new tool to improve the reliability of equipment. It uses a matrix form to help monitor anticipated component faults precisely. The tool provides the practical measures necessary to generate matrix tables that accurately display all causes of failure and all planned programmatic analyses, tests, processes, and inspections. When completed, the matrix tables give users in-depth visibility of the degree of protection against component failure that is provided by the program's preventive measure plans. The matrix form is an excellent technique for tracking, and thereby influencing, the reliability of nonelectronic spacecraft subsystems or components. No electronic applications have been tried, but the procedure can be useful in the electronics field, e.g., in integrated circuit production planning, and perhaps in process control, inspection or test lines for other electronic components. The drawing of forms, and the recording/manipulation of the data can be computerized.

Johnson, S. A.↗
NASA NTRS1987

Oxygen diffusion barrier coating

A method for coating a titanium panel or foil with aluminum and amorphous silicon to provide an oxygen barrier abrogating oxidation of the substrate metal is developed. The process is accomplished with known inexpensive procedures common in materials research laboratories, i.e., electron beam deposition and sputtering. The procedures are conductive to treating foil gage titanium and result in submicron layers which virtually add no weight to the titanium. There are no costly heating steps. The coatings blend with the substrate titanium until separate mechanical properties are subsumed by those of the substrate without cracking or spallation. This method appreciably increases the ability of titanium to mechanically perform in high thermal environments such as those witnessed on structures of space vehicles during re-entry

Unnam, Jalaiah↗
NASA NTRS1972

High-data-rate, spacecraft tape recorders.

Description of magnetic head designs, tape transport features, encoding techniques, bit error rates, and data rate capabilities of tape recorders used on board satellites for temporary storage of sensor data. Helical- and transverse-scan rotary head mechanisms used for wideband video signals from imaging systems are explained along with associated electronic circuitry. Decoding and decision procedures employed in multiple-track recorders are outlined, and deskewing electronics are discussed.

Thompson, C. R.↗
NASA NTRS1954

Determination of Flame Temperatures from 2000 to 3000 K by Microwave Absorption

Equations are derived for the measurement of flame temperatures from the attenuation of a microwave beam by temperature-induced free electrons from chemical elements introduced in the flame. Corrections are developed to account for the electron distribution in the flame. Procedure for obtaining the temperature from absorption is outlined. The free electron collision frequency and an effective ionization potential for four alkali elements were determined experimentally. The data were taken on a gas burner with a temperature range from 1900deg to 2400deg K. The effective ionization potential of sodium agrees with the spectral-line limit value. From these experimental ionization potentials and the experimental collision frequency, an accuracy of +/-600 K in the temperature was obtained. Fluctuating and average temperature data of a liquid propellant burner are presented primarily from 1.25-centimeter-wavelength microwave measurements in comparison with simultaneous two-color pyrometer and sound intensity measurements in the region from 2200deg to 2900deg K.

Kuhns, Perry W↗
NASA NTRS1997

Standardized Methods for Electronic Shearography

Research was conducted in development of operating procedures and standard methods to evaluate fiber reinforced composite materials, bonded or sprayed insulation, coatings, and laminated structures with MSFC electronic shearography systems. Optimal operating procedures were developed for the Pratt and Whitney Electronic Holography/Shearography Inspection System (EH/SIS) operating in shearography mode, as well as the Laser Technology, Inc. (LTI) SC-4000 and Ettemeyer SHS-94 ISTRA shearography systems. Operating practices for exciting the components being inspected were studied, including optimal methods for transient heating with heat lamps and other methods as appropriate to enhance inspection capability.

Lansing, Matthew D.↗
NASA NTRS1973

First measurements of electron temperature in the D region with a symmetric double probe

Measurement of the altitude profile of electron temperature in the ionospheric D region with the aid of a symmetric double probe flown on a Nike-Cajun payload launched on Oct. 13, 1971. The procedure for determining the electron temperature from the parameters of the double probe's current-voltage characteristic under conditions of nonnegligible ion-atom collision frequencies is described. It is shown that in its first lower ionospheric application the technique of the symmetric double probe has yielded the lowest values of electron temperature yet measured and has provided the very first direct measurement of electron temperature in the D region.

Szuszczewicz, E. P.↗
NASA NTRS1987

Electron-Focus Adjustment for Photo-Optical Imagers

Internal electron focus made independent of optical focus. Procedure enables fine tuning of internal electron-focusing system of photo-optical imager, without complication by imperfections of associated external optics. Applicable to imager in which electrons emitted from photocathode in optical focal plane, then electrostatically and/or magnetically focused to replica of image in second focal plane containing photodiodes, phototransistorss, charge-coupled devices, multiple-anode outputs, or other detectors.

Fowler, Walter B.↗
NASA NTRS1986

Testing Electronic Devices for Single-Event Upset

Report prepared describes equipment and summarizes both pretest and onsite procedures for testing of digital electronic devices for susceptibility to single-event upset. Term "single-event upset" denotes variety of temporary or permanent bit flips or latchup induced by single particles of ionizing radiation. Vacuum chamber houses device under test while exposed to ion beam. Vacuum chamber and associated equipment must be brought to ion-beam facility for test.

Nichols, D. K.↗
NASA NTRS1980

Effects of angular-momentum-changing collisions on dielectronic satellite spectra

A generalization of the low-density corona-model theory of the intensities of satellite lines of the resonance lines emitted by multiply charged helium-like ions in the X-ray spectra of high-temperature plasmas is developed in order to take account of electron collisional transitions between close autoionizing levels. A formalism for determining the population densities of the autoionizing levels and the satellite line intensities is presented, and the quantum mechanical calculation of autoionization, radiative decay and electron-induced collisional transitions is discussed. Generalized emission rate coefficients corresponding to dielectronic recombination and inner-shell-electron collisional excitation are tabulated as functions of electron density and temperature. The procedure is then used to illustrate the effects of angular-momentum-changing electron collisions on the intensities of the satellites of the 1s2p 1P to 1s2 1S resonance line of the ions Al XII and Si XIII. It is concluded that the collisional transitions have their most significant effect on the intensities of satellite transitions from metastable autoionizing states, which may be useful in determining plasma densities.

Jacobs, V. L.↗
DOE OSTI2024

Interpretable, extensible linear and symbolic regression models for charge density prediction using a hierarchy of many-body correlation descriptors

Here, density functional theory (DFT) is routinely used to make electronic structure predictions for high-throughput screening of materials and molecules for technologically relevant areas, like the identification of better catalysts, electronic materials, and drug discovery. However, the DFT formalism is limited by (a) its poor (quadratic-to-quartic) scaling, and (b) the need to perform repeated eigenvalue computations of the electronic Hamiltonian as part of its self-consistent field (SCF) iteration procedure to obtain the converged ground state electron density, ρ (r). Approaches that directly predict ρ (r) of a structure with high accuracy can accelerate conventional SCF calculations and can also be used in linearly scaling methods such as orbital-free DFT. To this end, we present a procedure to predict the ground state electron density of molecular and periodic three-dimensional systems directly from the atomic structure with a particular emphasis on physical interpretability. In our framework, ρ (r) is modeled using many-body correlation descriptors that accurately capture the effects of local atomic arrangements in the neighborhood of a grid point. Our use of a linear regression scheme to fit to charge density data enables transparent analysis of the relative contributions of various types of local atomic correlations. By systematically including increasingly complex correlations, our model is shown to accurately predict ρ (r) for a variety of chemically and electronically diverse systems — amorphous Ge, Al(001) slab, crystalline Ga 2 O 3 , molecular benzene, and polyethylene. We then demonstrate a symbolic regression-based protocol to construct easily computable, interpretable features from lower-order correlations that significantly improves our electron density predictions with effectively no increase in the computational cost.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1978

Quantum mechanical theory of collisional ionization in the presence of intense laser radiation

The paper presents a quantum mechanical formalism for treating ionizing collisions occurring in the presence of an intense laser field. Both the intense laser radiation and the internal electronic continuum states associated with the emitted electrons are rigorously taken into account by combining discretization techniques with expansions in terms of electronic-field representations for the quasi-molecule-plus-photon system. The procedure leads to a coupled-channel description of the heavy-particle dynamics which involves effective electronic-field potential surfaces and continua. It is suggested that laser-influenced ionizing collisions can be studied to verify the effects of intense laser radiation on inelastic collisional processes. Calculation procedures for electronic transition dipole matrix elements between discrete and continuum electronic states are outlined.

Bellum, J. C.↗