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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 163 records · Page 9

The CIV processes in the CRIT experiments

A qualitative analysis is conducted to reconcile the experimental data from critical ionization velocity (CIV) studies with CIV theories. The experimental data are reviewed demonstrating that: (1) the wave frequency is variable and low; (2) the wave polarization is almost isotropic; (3) electron energization is not easily reconciled with the observed wave spectrum; and (4) ambient electron density plays a role in determining CIV triggering conditions. Analytical treatment is given to the dispersion relation of the lower hybrid wave (LWH) instability driven by the streaming of an ion beam generated by the interaction of the neutral cloud with the ambient atmosphere. By incorporating the LWH instabilities of strong turbulence and finite-size effects into theoretical CIV relationships, the observations can be interpreted. The issues raised by the experimental data are understood within the context of a hypothesis of backward propagating nonlinearly collapsing wavepackets.

Papadopoulos, K.↗

OPAD status report - Investigation of SSME component erosion

Significant erosion of preburner faceplates was observed during recent SSME test firings at the NASA Technology Test Bed (TTB). The OPAD instrumentation acquired exhaust-plume spectral data during each test which indicate the occurrence of metallic species consistent with faceplate component composition. A qualitative analysis of the spectral data was conducted to evaluate the state of the engine versus time for each test according to the nominal conditions of TTB firing number 17 and number 18. In general the analyses indicate abnormal erosion levels at or near startup. Subsequent to the initial erosion event, signal levels tend to decrease towards nominal baseline values. These findings, in conjunction with post-test engine inspections, suggest that in cases under study, the erosion may not have been catastrophic to the immediate operation of the engine.

Powers, W. T.↗

On the aerodynamics and performance of active vortex generators

As a building block in the development of smart lift-enhancement devices, a new concept for flow control using active vortex generators (AVGs) is presented. Ramp, wedge, and doublet wedge (Wheeler) VG configurations are investigated. The AVGs are designed to conform to the surface of the wing section at low alpha. As the section approaches the stall, they are deployed and accordingly, alpha(stall) and C(lmax) are increased. A qualitative analysis of the flow around the various VG configurations was conducted in a low speed wind tunnel at 1.6 ft/s and a Reynolds number of approximately 3400. The results demonstrate that ramp VGs produce vortices that have the longest distance at breakdown. The VGs were also applied to a 25-in. span, 8-in. chord NACA 4415 wing section. Optimization studies were conducted on the spanwise spacing, chordwise position, and size of statically deployed VGs. The test results demonstrate a 14-percent increase in C(lmax) while increasing alpha (stall) by up to 3.

Barrett, Ron↗

Building an experience factory for maintenance

This paper reports the preliminary results of a study of the software maintenance process in the Flight Dynamics Division (FDD) of the National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC). This study is being conducted by the Software Engineering Laboratory (SEL), a research organization sponsored by the Software Engineering Branch of the FDD, which investigates the effectiveness of software engineering technologies when applied to the development of applications software. This software maintenance study began in October 1993 and is being conducted using the Quality Improvement Paradigm (QIP), a process improvement strategy based on three iterative steps: understanding, assessing, and packaging. The preliminary results represent the outcome of the understanding phase, during which SEL researchers characterized the maintenance environment, product, and process. Findings indicate that a combination of quantitative and qualitative analysis is effective for studying the software maintenance process, that additional measures should be collected for maintenance (as opposed to new development), and that characteristics such as effort, error rate, and productivity are best considered on a 'release' basis rather than on a project basis. The research thus far has documented some basic differences between new development and software maintenance. It lays the foundation for further application of the QIP to investigate means of improving the maintenance process and product in the FDD.

Valett, Jon D.↗

The Nature of Comet Materials and Attachment to Them

Because cometary surfaces are likely to be far colder and of a different composition and surface topography than other planetary surfaces with which we have experience, there are some new considerations that must be examined in regards to placing and attaching instrumented packages or sample return devices in or on their surfaces. The qualitative analysis of the problem of embedding hardware in a comet icy core is limited to only one of several means for the purposes of this discussion. This means can be characterized as a kinetic impact piercing device. Such kinetic impact piercing device may be used to attach the feet of an instrumented package on the surface or it may be the means for implanting the package in the icy core below the mantle. The functional requirement is to implant a device in the icy core and by mechanical means, prevent the device from being ejected back into space.

Stephens, James↗

Solid State Laser

The Titan-CW Ti:sapphire (titanium-doped sapphire) tunable laser is an innovation in solid-state laser technology jointly developed by the Research and Solid State Laser Divisions of Schwartz Electro-optics, Inc. (SEO). SEO is producing the laser for the commercial market, an outgrowth of a program sponsored by Langley Research Center to develop Ti:sapphire technology for space use. SEO's Titan-CW series of Ti:sapphire tunable lasers have applicability in analytical equipment designed for qualitative analysis of carbohydrates and proteins, structural analysis of water, starch/sugar analyses, and measurements of salt in meat. Further applications are expected in semiconductor manufacture, in medicine for diagnosis and therapy, and in biochemistry.

Source record↗

Designing It Smart With SIV

When research staff at NASA s Glenn Research Center developed and patented Stereo Imaging Velocimetry (SIV), the world s first three-dimensional (3-D), full-field quantitative and qualitative analysis tool to investigate flow velocities, experiments that were previously impossible became a reality. Seizing the opportunity to commercialize NASA s breakthrough invention, Digital Interface Systems (DIS), Inc., of North Olmsted, Ohio, acquired an exclusive license to market SIV, which has a range of applications from improving the aerodynamics of aircraft and automobiles to avoiding "no flow" regions in artificial hearts.

Source record↗

Journal of Air Transportation, Volume 9, No. 1

The articles in this issue include: 1) Are Four Year Universities Better than Two-Year Colleges at Preparing Students to Pass the FAA Aircraft Mechanic Certification Written Examinations? 2) Assessing Perceived Risk of Consumers in Internet Airline Reservations Services; 3) Perceptions of Communication Training Among Collegiate Flight Educators; 4) Ethics Education in University Aviation Management Programs in the U.S.: Part Three - Qualitative Analysis and Recommendations; 5) Airline Flight Operations Internships Perspectives; 6) Applying Data Mining Techniques to Forecast Number of Airline Passengers in Saudi Arabia (Domestic and International Travels).

Bowen, Brent D.↗

SimGraph: A Flight Simulation Data Visualization Workstation

Today's modern flight simulation research produces vast amounts of time sensitive data, making a qualitative analysis of the data difficult while it remains in a numerical representation. Therefore, a method of merging related data together and presenting it to the user in a more comprehensible format is necessary. Simulation Graphics (SimGraph) is an object-oriented data visualization software package that presents simulation data in animated graphical displays for easy interpretation. Data produced from a flight simulation is presented by SimGraph in several different formats, including: 3-Dimensional Views, Cockpit Control Views, Heads-Up Displays, Strip Charts, and Status Indicators. SimGraph can accommodate the addition of new graphical displays to allow the software to be customized to each user s particular environment. A new display can be developed and added to SimGraph without having to design a new application, allowing the graphics programmer to focus on the development of the graphical display. The SimGraph framework can be reused for a wide variety of visualization tasks. Although it was created for the flight simulation facilities at NASA Langley Research Center, SimGraph can be reconfigured to almost any data visualization environment. This paper describes the capabilities and operations of SimGraph.

Kaplan, Joseph A.↗

Method and Apparatus for the Quantification of Particulate Adhesion Forces on Various Substrates

Mitigation strategies for lunar dust adhesion have typically been limited to qualitative analysis. This technical memorandum describes the generation and operation of an adhesion testing device capable of quantitative assessment of adhesion forces between particulates and substrates. An aerosolization technique is described to coat a surface with a monolayer of particulates. Agitation of this surface, via sonication, causes particles to dislodge and be gravitationally fed into an optical particle counter. Experimentally determined adhesion force values are compared to forces calculated from van der Waals interactions and are used to calculate the work of adhesion using Johnson-Kendall-Roberts (JKR) theory. Preliminary results indicate that a reduction in surface energy and available surface area, through topographical modification, improve mitigation of particulate adhesion.

Wohl, Christopher J.↗

Astronaut Biography Project for Countermeasures of Human Behavior and Performance Risks in Long Duration Space Flights

This final report will summarize research that relates to human behavioral health and performance of astronauts and flight controllers. Literature reviews, data archival analyses, and ground-based analog studies that center around the risk of human space flight are being used to help mitigate human behavior and performance risks from long duration space flights. A qualitative analysis of an astronaut autobiography was completed. An analysis was also conducted on exercise countermeasure publications to show the positive affects of exercise on the risks targeted in this study. The three main risks targeted in this study are risks of behavioral and psychiatric disorders, risks of performance errors due to poor team performance, cohesion, and composition, and risks of performance errors due to sleep deprivation, circadian rhythm. These three risks focus on psychological and physiological aspects of astronauts who venture out into space on long duration space missions. The purpose of this research is to target these risks in order to help quantify, identify, and mature countermeasures and technologies required in preventing or mitigating adverse outcomes from exposure to the spaceflight environment

Banks, Akeem↗

Interdisciplinary Interactions During R&D and Early Design of Large Engineered Systems

Designing Large-Scale Complex Engineered Systems (LaCES) such as aircraft and submarines requires the input of thousands of engineers and scientists whose work is proximate in neither time nor space. Comprehensive knowledge of the system is dispersed among specialists whose expertise is in typically one system component or discipline. This study examined the interactive work practices among such specialists seeking to improve engineering practice through a rigorous and theoretical understanding of current practice. This research explored current interdisciplinary practices and perspectives during R&D and early LaCES design and identified why these practices and perspectives prevail and persist. The research design consisted of a three-fold, integrative approach that combined an open-ended survey, semi-structured interviews, and ethnography. Significant empirical data from experienced engineers and scientists in a large engineering organization were obtained and integrated with theories from organization science and engineering. Qualitative analysis was used to obtain a holistic, contextualized understanding. The over-arching finding is that issues related to cognition, organization, and social interrelations mostly dominate interactions across disciplines. Engineering issues, such as the integration of hardware or physics-based models, are not as significant. For example, organization culture is an important underlying factor that guided researchers more toward individual sovereignty over cross-disciplinarity. The organization structure and the engineered system architecture also serve as constraints to the engineering work. Many differences in work practices were observed, including frequency and depth of interactions, definition or co-construction of requirements, clarity or creation of the system architecture, work group proximity, and cognitive challenges. Practitioners are often unaware of these differences resulting in confusion and incorrect assumptions regarding work expectations. Cognitively, the enactment and coconstruction of knowledge are the fundamental tasks of the interdisciplinary interactions. Distributed and collective cognition represent most of the efforts. Argument, ignorance, learning, and creativity are interrelated aspects of the interactions that cause discomfort but yield benefits such as problem mitigation, broader understanding, and improved system design and performance. The quality and quantity of social interrelations are central to all work across disciplines with reciprocity, respectful engagement, and heedful interrelations being significant to the effectiveness of the engineering and scientific work.

McGowan, Anna-Maria Rivas↗

Herschel's "Cold Debris Disks": Background Galaxies or Quiescent Rims of Planetary Systems?

Infrared excesses associated with debris disk host stars detected so far peak at wavelengths around approx, 100 micron or shorter. However, 6 out of 31 excess sources studied in the Herschel Open Time Key Programme, DUNES, have been seen to show significant-and in some cases extended-excess emission at 160 micron, which is larger than the 100 micron excess. This excess emission has been attributed to circumstellar dust and has been suggested to stem from debris disks colder than those known previously. Since the excess emission of the cold disk candidates is extremely weak, challenging even the unrivaled sensitivity of Herschel, it is prudent to carefully consider whether some or even all of them may represent unrelated galactic or extragalactic emission, or even instrumental noise. We re-address these issues using several distinct methods and conclude that it is highly unlikely that none of the candidates represents a true circumstellar disk. For true disks, both the dust temperatures inferred from the spectral energy distributions and the disk radii estimated from the images suggest that the dust is nearly as cold as a blackbody. This requires the grains to be larger than approx. 100 micron, even if they are rich in ices or are composed of any other material with a low absorption in the visible. The dearth of small grains is puzzling, since collisional models of debris disks predict that grains of all sizes down to several times the radiation pressure blowout limit should be present. We explore several conceivable scenarios: transport-dominated disks, disks of low dynamical excitation, and disks of unstirred primordial macroscopic grains. Our qualitative analysis and collisional simulations rule out the first two of these scenarios, but show the feasibility of the third one. We show that such disks can indeed survive for gigayears, largely preserving the primordial size distribution. They should be composed of macroscopic solids larger than millimeters, but smaller than a few kilometers in size. If larger planetesimals were present, then they would stir the disk, triggering a collisional cascade and thus causing production of small debris, which is not seen. Thus, planetesimal formation, at least in the outer regions of the systems, has stopped before "cometary" or "asteroidal" sizes were reached.

Herschel↗

Anomalous Variability in Antarctic Sea Ice Extents During the 1960s With the Use of Nimbus Data

The Nimbus I, II, and III satellites provide a new opportunity for climate studies in the 1960s. The rescue of the visible and infrared imager data resulted in the utilization of the early Nimbus data to determine sea ice extent. A qualitative analysis of the early NASA Nimbus missions has revealed Antarctic sea ice extents that are significant larger and smaller than the historic 1979-2012 passive microwave record. The September 1964 ice mean area is 19.7x10(exp 6) sq. km +/- 0.3x10(exp 6) sq. km. This is more the 250,000 sq. km greater than the 19.44x10(exp 6) sq. km seen in the new 2012 historic maximum. However, in August 1966 the maximum sea ice extent fell to 15.9x10(exp 6) sq. km +/- 0.3x10(exp 6) sq. km. This is more than 1.5x10(exp 6) sq. km below the passive microwave record of 17.5x10(exp 6) sq. km set in September of 1986. This variation between 1964 and 1966 represents a change of maximum sea ice of over 3x10(exp 6) sq. km in just two years. These inter-annual variations while large, are small when compared to the Antarctic seasonal cycle.

Antarctic↗

Anomalous Variability in Antarctic Sea Ice Extents During the 1960s With the Use of Nimbus Data

The Nimbus I, II, and III satellites provide a new opportunity for climate studies in the 1960s. The rescue of the visible and infrared imager data resulted in the utilization of the early Nimbus data to determine sea ice extent. A qualitative analysis of the early NASA Nimbus missions has revealed Antarctic sea ice extents that are signicant larger and smaller than the historic 1979-2012 passive microwave record. The September 1964 ice mean area is 19.7x10 km +/- 0.3x10 km. This is more the 250,000 km greater than the 19.44x10 km seen in the new 2012 historic maximum. However, in August 1966 the maximum sea ice extent fell to 15.9x10 km +/- 0.3x10 km. This is more than 1.5x10 km below the passive microwave record of 17.5x10 km set in September of 1986. This variation between 1964 and 1966 represents a change of maximum sea ice of over 3x10 km in just two years. These inter-annual variations while large, are small when compared to the Antarctic seasonal cycle.

Sea Ice↗

Position Paper: Designing Complex Systems to Support Interdisciplinary Cognitive Work

The paper argues that the field we can call cognitive science of interdisciplinary collaboration is an important area of study for improving design of Large-Scale Complex Systems (LaCES) and supporting cognitive work. The paper mostly raised questions that have been documented in earlier qualitative analysis studies, and provided possible avenues of exploration for addressing them. There are likely further contributions from additional disciplines beyond those mentioned in this paper that should be considered and integrated into such a cognitive science framework. Knowledge and awareness of various perspectives will help to inform the types of interventions available for improving LaCES design and functionality. For example, a cognitive interpretation of interdisciplinary collaborations in LaCES elucidated the need for a "translator" or "mediator" in helping subject matter experts to transcend language boundaries, mitigate single discipline bias, support integrative activities, and correct misaligned objectives. Additional research in this direction is likely to uncover similar gaps and opportunities for improvements in practice.

Greene, Melissa T.↗

Segmented Ion Engine Plume Characteristics

Preliminary evaluation of the segmented ion thruster (SIT) ion beam characteristics was performed by measuring the two dimensional ion current density distribution at four axial locations downstream from the thruster. Current density profiles were measured with the concurrent operation of multiple ion sources. Preliminary assessments regarding symmetry of the plume, characterization of plume development as a function of axial position, and the interactions of multiple simultaneously operating ion sources were conducted. A numerical integration scheme was applied to the acquired data to determine the total beam current. A qualitative analysis of the downstream development of the ion beam was conducted. Most of the data acquired so far has been on somewhat of a trial basis and extensive testing is scheduled to resume in August 1994.

ion↗

A Multi‐Probe Automated Classification of Ice Crystal Habits During the IMPACTS Campaign

Although all ice crystals are unique, many can be grouped together by shape or habit, with members of a habit class sharing similar representations of properties such as fall velocity and growth rate. A decision tree algorithm designed to be adaptable to any particle imaging probe, thus enabling the creation of habit size distributions over a size range larger than that of any probe on its own, is used to classify ice crystals imaged by three airborne cloud probes in mid-latitude winter cyclones during the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field campaign. Crystals are sorted into seven habit classes based on their morphological properties: sphere, column/needle, plate, graupel, dendrite, aggregate, and irregular. Although adaptability was its primary goal, the algorithm was found to be moderately skillful for identifying idealized habit images. Quantitative tests of the algorithm’s adaptability displayed mixed results, as Two-Dimensional Stereo Probe (2DS) classifications showed moderate correlation with Particle Habit Imaging and Polar Scattering Probe (PHIPS) classifications, but only weak correlation with High Volume Precipitation Spectrometer (HVPS) classifications. The algorithm was applied to random sets of images from each probe in a case study of a mesoscale snow band sampled on 7 February 2020. In the case study, qualitative analysis of particle images revealed general agreement on classifications among the probes, supporting the algorithm’s applicability to multiple cloud probes. Most classifications appeared correct upon manual inspection, suggesting that in practical use, the algorithm is reasonably able to classify non-idealized images.

Julian Schima↗