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  • Other Sources  (358)
  • 2010-2014  (348)
  • 1940-1944  (10)
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  • 1
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    Nondestructive Crack Detection in a Fuel System Component (2010)
    In:  Other Sources
    Details
    Publication Date: 2019-07-19
    Description: The paper discusses development of various NDE techniques to detect cracks in A40 steel poppets used in a valve of the fuel system of the Space Shuttle Orbiter. The valve assembly experiences a severe high cycle fatigue environment during its operation. Cracks were discovered at the radius of the poppet flange. Experience shows that very small cracks or material anomalies do not cause failure in a single operation event. While the design is being modified to eliminate the issue, NDE has been used to screen the poppets for cracks before every use. Several surface flaw detection techniques were considered and a few NDE techniques were developed to provide NDE screening for the flaw detection. The primary method used was the eddy current testing. In the eddy current technique, the X-Y channel test data from the eddy current instrument was recorded as computer files. A Matlab data review and plotting application was developed to analyze the data files. The Matlab application provides much higher resolution than the eddy current instrument that was used to acquire the data. Other techniques that were used included ultrasonic surface wave and magnetic particle testing. A probability of detection (POD) study was undertaken to determine the 90/95 size for the eddy current technique. This study used specimens with same geometry and material as the poppet. Fatigue cracks were grown in these specimens. Information on results of the NDE techniques and results of the POD study are provided.
    Keywords: Propellants and Fuels
    Type: JSC-CN-19224 , JSC-CN-19296 , Aircraft Airworthiness and Sustainment Conference; May 10, 2010 - May 13, 2010; Austin, Texas; United States|ASNT Research Symposium and Spring Conference; Mar 22, 2010 - Mar 26, 2010; Williamsburg, VA; United States
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  • 2
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    An Evolving Compact Jet in the Black Hole X-Ray Binary Maxi J1836-194 (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from approx 10(exp 11) to approx 4 10(exp 13) Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN10528 , The Astrophysical Journal; 768; 2; L35
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  • 3
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    NDT and SHM of Carbon Fiber Composites using Linear Drive MWM-Arrays (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Composite Materials
    Type: KSC-2013-057 , ASM AeroMat 2013 Conference; Apr 02, 2013 - Apr 05, 2013; Bellevue, WA; United States
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  • 4
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    Continued Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of Composite Overwrapped Pressure Vessels (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-19
    Description: Composite Overwrapped Pressure Vessels (COPVs) are used in essentially all NASA spacecraft, launch. vehicles and payloads to contain high-pressure fluids for propulsion, life support systems and science experiments. Failure of any COPV either in flight or during ground processing would result in catastrophic damage to the spacecraft or payload, and could lead to loss of life. Therefore, NASA continues to investigate new methods to non-destructively inspect (NDE) COPVs for structural anomalies and to provide a means for in-situ structural health monitoring (SHM) during operational service. Partnering with JENTEK Sensors, engineers at NASA, Kennedy Space Center have successfully conducted a proof-of-concept study to develop Meandering Winding Magnetometer (MWM) eddy current sensors designed to make direct measurements of the stresses of the internal layers of a carbon fiber composite wrapped COPV. During this study three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed good correlation with actual surface strain gage measurements. MWM-Array technology for scanning COPVs can reliably be used to image and detect mechanical damage. To validate this conclusion, several COPVs were scanned to obtain a baseline, and then each COPV was impacted at varying energy levels and then rescanned. The baseline subtracted images were used to demonstrate damage detection. These scans were performed with two different MWM-Arrays. with different geometries for near-surface and deeper penetration imaging at multiple frequencies and in multiple orientations of the linear MWM drive. This presentation will include a review of micromechanical models that relate measured sensor responses to composite material constituent properties, validated by the proof of concept study, as the basis for SHM and NDE data analysis as well as potential improvements including design changes to miniaturize and make the sensors durable in the vacuum of space
    Keywords: Quality Assurance and Reliability
    Type: KSC-2011-289 , 2012 Aircraft Airworthiness and Sustainment Conference; Apr 02, 2012 - Apr 05, 2012; Baltimore, MD; United States
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  • 5
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    Nondestructive Crack Detection in a Fuel System Component (2010)
    In:  CASI
    Details
    Publication Date: 2019-08-13
    Description: The presentation examines the background and objective of nondestructive crack detection, flow control valve assembly and poppet post flight evaluation, poppet properties. magnetic property characterization of lab data, NDE, eddy current inspection, simulation, eddy current criteria, poppet cycle testing and NDE criteria, and the use of ultrasonic surface wave for crack detection.
    Keywords: Quality Assurance and Reliability
    Type: JSC-CN-20150 , 2010 Aircraft Airworthiness and Sustainment Conference; May 10, 2010 - May 13, 2010; Austin, TX; United States
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  • 6
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    NDT and SHM of Carbon Fiber Composites using Linear Drive MWM-Arrays (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-19
    Description: Carbon fiber composites are used in a wide range of structural applications due to their excellent specific strength and stiffness. However, the anisotropic mechanical and electrical properties associated with the fibers within each composite layer present challenges, and opportunities, for Nondestructive Testing (NDT) methods used to characterize and assess the structure condition. This includes composite condition after manufacture (such as fiber orientation and density, porosity, delamination, and bond strength) and during usage (such as damage from impact, fiber breakage, thermal exposure or applied stress). Ultrasonic and thermographic methods can address some of these challenges, but eddy current methods provide an alternative method for composite structures that contain a conducting material, such as carbon fibers or a metallic liner. This presentation reviews recent advances in the development of eddy current sensors and arrays for carbon fiber composite NDT and Structural Health Monitoring (SHM) applications. The focus is on eddy current sensor constructs with linear drive windings, such as MWM -Arrays, that induce currents primarily within the linear fibers of the composite. By combining this type of sensor construct with micromechanical models that relate composite constituent properties to measurable sensor responses, insight is obtained into the volumetric distribution of electrical properties within the composite and the associated manufacturing, damage, or strain conditions. With knowledge of the fiber layup, this MWM-Array technology is able to detect damage and strain/stress as a function of depth and fiber orientation. This work has been funded by NASA, NA V AIR and the Army for applications ranging from composite overwrapped pressure vessels (COPVs) to aircraft structures and rotorcraft blades. This presentation will specifically present background on the MWM-Array technology, results from the micromechanical modeling effort, and results from ongoing efforts for high resolution imaging and volumetric strain sensing.
    Keywords: Composite Materials
    Type: KSC-2012-294 , Aeromat Conference; Apr 02, 2013 - Apr 05, 2013; Bellevue, WA; United States
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  • 7
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    Aquifer storage and recovery (2010)
    Department of Water, Land and Biodiversity Conservation, Adelaide, SA
    Details
    Publication Date: 2021-03-29
    Description: Aquifer Storage and Recovery (ASR) has the potential to utilise surface water resources, including urban stormwater runoff and treated wastewater that is largely wasted; thereby relieving the pressure on groundwater resources. In the broader sense, opportunities exist to use ASR to rethink our traditional water management and distribution policies, and to provide cost-effective and innovative alternatives to current methods of water supply. In South Australia, an increasing amount of stress is being placed on surface and groundwater resources to meet demands from expanding irrigated horticultural areas and urban populations. ASR can be used to reduce some of the pressure on traditional supplies of water, especially in metropolitan areas. But the sources of water for ASR must be carefully considered especially in rural areas so as not to shift the burden from one water supply source to another. A number of issues surround the use of ASR as a water management solution and these relate principally to water quality and water quantity. In rural areas, for example, the 'harvesting' of water from creeks and streams may result in extra pressure on an already stressed resource by further reducing the amount of water available to the environment. In urban areas the expanse of paved surfaces provides an ideal medium to capture large volumes of stormwater runoff. However, the volumes are often well in excess of any potential local demand. Understanding ASR technology ensures success in almost all situations ...
    Description: report
    Keywords: 910 ; UDY 000 ; Australien und Ozeanien {Hydrologie}
    Language: English
    Type: article , publishedVersion
    Format: 63 S.
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    CITATION GEO-LEO
  • 8
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    Eyre Peninsula water management geographic information system (2010)
    Department of Water, Land and Biodiversity Conservation, Adelaide, SA
    Details
    Publication Date: 2021-03-29
    Description: Groundwater is Eyre Peninsula's most precious resource and has become the sole source of reticulated water to meet potable and industrial demand. Water resources on Eyre Peninsula are scarce and fragile, particularly in the low rainfall regions, with few reliable freshwater streams and the groundwater availability is highly variable. The groundwater recharge and hence the security of the resource, is highly dependent upon local rainfall, landcover and landuse. Surface water is scarce and unreliable, and reticulated water is limited. Difficulty in accessing water resources has placed both a social and economic burden on the rural community throughout the region. The information contained on the CD will provide a vital framework for the future management planning of the available resources in the region.
    Description: report
    Keywords: 910 ; UDY 000 ; Australien und Ozeanien {Hydrologie}
    Language: English
    Type: article , publishedVersion
    Format: 12 S.
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    CITATION GEO-LEO
  • 9
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    Assessing Requirements Volatility and Risk Using Bayesian Networks (2010)
    In:  CASI
    Details
    Publication Date: 2018-06-12
    Description: There are many factors that affect the level of requirements volatility a system experiences over its lifecycle and the risk that volatility imparts. Improper requirements generation, undocumented user expectations, conflicting design decisions, and anticipated / unanticipated world states are representative of these volatility factors. Combined, these volatility factors can increase programmatic risk and adversely affect successful system development. This paper proposes that a Bayesian Network can be used to support reasonable judgments concerning the most likely sources and types of requirements volatility a developing system will experience prior to starting development and by doing so it is possible to predict the level of requirements volatility the system will experience over its lifecycle. This assessment offers valuable insight to the system's developers, particularly by providing a starting point for risk mitigation planning and execution.
    Keywords: Systems Analysis and Operations Research
    Type: Selected Papers Presented at MODSIM World 2009 Conference and Expo; 89-101; NASA/CP-2010-216205
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  • 10
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    Constraining the Properties of the Eta Carinae System via 3-D SPH Models of Space-Based Observations: The Absolute Orientation of the Binary Orbit (2011)
    In:  CASI
    Details
    Publication Date: 2018-06-06
    Description: The extremely massive (〉 90 Stellar Mass) and luminous (= 5 x 10(exp 6) Stellar Luminosity) star Eta Carinae, with its spectacular bipolar "Homunculus" nebula, comprises one of the most remarkable and intensely observed stellar systems in the Galaxy. However, many of its underlying physical parameters remain unknown. Multiwavelength variations observed to occur every 5.54 years are interpreted as being due to the collision of a massive wind from the primary star with the fast, less dense wind of a hot companion star in a highly elliptical (e approx. 0.9) orbit. Using three-dimensional (3-D) Smoothed Particle Hydrodynamics (SPH) simulations of the binary wind-wind collision, together with radiative transfer codes, we compute synthetic spectral images of [Fe III] emission line structures and compare them to existing Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) observations. We are thus able, for the first time, to tightly constrain the absolute orientation of the binary orbit on the sky. An orbit with an inclination of approx. 40deg, an argument of periapsis omega approx. 255deg, and a projected orbital axis with a position angle of approx. 312deg east of north provides the best fit to the observations, implying that the orbital axis is closely aligned in 3-D space with the Homunculus symmetry axis, and that the companion star orbits clockwise on the sky relative to the primary.
    Keywords: Astronomy
    Type: Bulletin de la Societe Royale des Sciences de Liege; Volume 80; 694-698
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