STEM Engagement with NASA's Solar System Treks Portals for Lunar and Planetary Mapping and Modeling
Document ID: 20180002098NTRS Full-Text: Click to View [PDF Size: 226 KB]
Author: Law, E. S.; Day, B. H.
Abstract: This presentation will provide an overview of the uses and capabilities of NASA's Solar System Treks
family of online mapping and modeling portals. While also designed to support mission planning and scientific research, this presentation will focus on the Science, Technology, Engineering, and Math (STEM) engagement and public outreach capabilities of these web based suites of data visualization and analysis tools.
Publication Year: 2018Document Type: Conference PaperReport/Patent Number: ARC-E-DAA-TN52941Date Acquired: Apr 06, 2018
Test and Analysis of a Buckling-Critical Large-Scale Sandwich Composite Cylinder
Document ID: 20180002092NTRS Full-Text: Click to View [PDF Size: 863 KB]
Author: Schultz, Marc R.; Sleight, David W.; Gardner, Nathaniel W.; Rudd, Michelle T.; Hilburger, Mark W.; Palm, Tod E.; Oldfield, Nathan J.
Abstract: Structural stability is an important design consideration for launch-vehicle shell structures and it
is well known that the buckling response of such shell structures can be very sensitive to small geometric imperfections. As part of an effort to develop new buckling design guidelines for sandwich composite cylindrical shells, an 8-ft-diameter honeycomb-core sandwich composite cylinder was tested under pure axial compression to failure. The results from this test are compared with finite-element-analysis predictions and overall agreement was very good. In particular, the predicted buckling load was within 1% of the test and the character of the response matched well. However, it was found that the agreement could be improved by including composite material nonlinearity in the analysis, and that the predicted buckling initiation site was sensitive to the addition of small bending loads to the primary axial load in analyses.
Publication Year: 2018Document Type: Conference PaperReport/Patent Number: NF1676L-27252Date Acquired: Apr 06, 2018
Knowledge Discovery Process: Case Study of RNAV Adherence of Radar Track Data
Document ID: 20180002099NTRS Full-Text: Click to View [PDF Size: 13.7 MB]
Author: Matthews, Bryan
Abstract: This talk is an introduction to the knowledge discovery process, beginning with: identifying the
problem, choosing data sources, matching the appropriate machine learning tools, and reviewing the results. The overview will be given in the context of an ongoing study that is assessing RNAV adherence of commercial aircraft in the national airspace.
Publication Year: 2018Document Type: Oral/Visual PresentationReport/Patent Number: ARC-E-DAA-TN54223Date Acquired: Apr 06, 2018
The Effect of Forward-Facing Steps on Stationary Crossflow Instability Growth and Breakdown
Document ID: 20180002093NTRS Full-Text: Click to View [PDF Size: 4.8 MB]
Author: Eppink, Jenna L.
Abstract: The e?ect of a forward-facing step on stationary cross?ow transition was studied using standard
stereo particle image velocimetry (PIV) and time-resolved PIV. Step heights ranging from 53 to 71% of the boundary-layer thickness were studied in detail. The steps above a critical step height of approximately 60% of the boundary-layer thickness had a signi?cant impact on the stationary cross?ow growth downstream of the step. For the critical cases, the stationary cross?ow amplitude grew suddenly downstream of the step, decayed for a short region, then grew again. The adverse pressure gradient upstream of the step resulted in a region of cross?ow reversal. A secondary set of vortices, rotating in the opposite direction to the primary vortices, developed underneath the uplifted primary vortices. The wall-normal velocity disturbance (V' ) created by these secondary vortices impacted the step, and is believed to feed into the strong vortex that developed downstream of the step. A large but very short negative cross?ow region formed for a short region downstream of the step due to a sharp inboard curvature of the streamlines near the wall. For the larger step height cases, a cross?ow-reversal region formed just downstream of the strong negative cross?ow region. This cross?ow reversal region is believed to play an important role in the growth of the stationary cross?ow vortices downstream of the step, and may be a good indication of the critical forward-facing step height.
Publication Year: 2018Document Type: Conference PaperReport/Patent Number: NF1676L-28876Date Acquired: Apr 06, 2018
An Overview of NUCAPS Soundings Research to Operations Activities to Support Operational Forecasting Challenges
Document ID: 20180002088NTRS Full-Text: Click to View [PDF Size: 3.7 MB]
Author: Berndt, Emily; Zavodsky, Brad
Abstract: No abstract available
Publication Year: 2018Document Type: Oral/Visual PresentationReport/Patent Number: MSFC-E-DAA-TN54286Date Acquired: Apr 06, 2018
Analysis of Multi-Flight Common Routes for Traffic Flow Management
Document ID: 20180002100NTRS Full-Text: Click to View [PDF Size: 5.0 MB]
Author: Sheth, Kapil; Clymer, Alexis; Morando, Alex; Shih, Fu-Tai
Abstract: When severe convective weather requires rerouting aircraft, FAA traffic managers employ severe
weather avoidance plans (e.g., Playbook routes, Coded Departure Routes, etc.) These routes provide pilots with safe paths around weather-affected regions, and provide controllers with predictable, and often well-established flight plans. However, they often introduce large deviations to the nominal flight plans, which may not be necessary as weather conditions change. If and when the imposed traffic management initiatives (TMIs) become stale, updated shorter path flight trajectories may be found en route, providing significant time-savings to the affected flights. Multiple Flight Common Routes (MFCR) is a concept that allows multiple flights that are within a specified proximity or region, to receive updated shorter flight plans in an operationally efficient manner. MFCR is believed to provide benefits to the National Airspace System (NAS) by allowing traffic managers to update several flight plans of en route aircraft simultaneously, reducing operational workload within the TMUs of all affected ARTCCs. This paper will explore some aspects of the MFCR concept by analyzing multiple flights that have been selected for rerouting by the NAS Constraint Evaluation and Notification Tool (NASCENT). Various methods of grouping aircraft with common or similar routes will be presented, along with a comparison of the efficacy of these methods.
Publication Year: 2016Document Type: Conference PaperReport/Patent Number: AIAA Paper 2016-4207, ARC-E-DAA-TN28055Date Acquired: Apr 06, 2018
Age Distribution of Lunar Impact-Melt Rocks in Apollo Drive-Tube 68001/2
Document ID: 20180002080NTRS Full-Text: Click to View [PDF Size: 3.4 MB]
Author: Curran, N. M.; Bower, D. M.; Frasl, B.; Cohen, B. A.
Abstract: Apollo 16 double-drive tube 68001 /68002 provides impact and volcanic materials along a depth of
approximately 60 cm in five compositional distinct units. 68001 /2 offers the potential to study distinct populations of impact melts with depth to understand how 'gardening' affects these samples. We will use unbiased major-element chemistry, mineralogy, and age to understand the impact history of Apollo 16 landing site. The study demonstrates the techniques that landed missions require to identify lithologies of interest (e.g., impact melts).
Publication Year: 2018Document Type: Oral/Visual PresentationReport/Patent Number: GSFC-E-DAA-TN54187Date Acquired: Apr 06, 2018
Connective Heating Improvement for Emergency Fire Shelters (CHIEFS): Composition and Performance of Fire Shelter Concepts at Close-Out
Document ID: 20180002094NTRS Full-Text: Click to View [PDF Size: 2.9 MB]
Author: Fody, Joshua M.; Daryabeigi, Kamran; Bruce, Walter E., III; Wells, John M.; Wusk, Mary E.; Calomino, Anthony M.; Miller, Steve D.
Abstract: Summary of highlights of the Convective Heating Improvement for Emergency Fire Shelters (CHIEFS)
taskunder NASA. CHIEFS was tasked with providing the US Forest Service with an emergency fire shelter forimproved resistance to flame contact. Emphasis is on the final shelter designs at task close-out (end of FY17).
Publication Year: 2018Document Type: Technical ReportReport/Patent Number: NASA/TM-2018-219813, NF1676L-29496, L-20910Date Acquired: Apr 06, 2018
A Recording-Based Method for Auralization of Rotorcraft Flyover Noise
Document ID: 20180002090NTRS Full-Text: Click to View [PDF Size: 1.6 MB]
Author: Pera, Nicholas M.; Rizzi, Stephen A.; Krishnamurthy, Siddhartha; Fuller, Christopher R.; Christian, Andrew
Abstract: Rotorcraft noise is an active field of study as the sound produced by these vehicles is often found
to be annoying. A means to auralize rotorcraft flyover noise is sought to help understand the factors leading to annoyance. Previous work by the authors focused on auralization of rotorcraft fly-in noise, in which a simplification was made that enabled the source noise synthesis to be based on a single emission angle. Here, the goal is to auralize a complete flyover event, so the source noise synthesis must be capable of traversing a range of emission angles. The synthesis uses a source noise definition process that yields periodic and aperiodic (modulation) components at a set of discrete emission angles. In this work, only the periodic components are used for the source noise synthesis for the flyover; the inclusion of modulation components is the subject of ongoing research. Propagation of the synthesized source noise to a ground observer is performed using the NASA Auralization Framework. The method is demonstrated using ground recordings from a flight test of the AS350 helicopter for the source noise definition.
Publication Year: 2018Document Type: Conference PaperReport/Patent Number: NF1676L-25385Date Acquired: Apr 06, 2018
Using Concurrent Cardiovascular Information to Augment Survival Time Data for Evaluating Orthostatic Tilt Test Performance
Document ID: 20180002178NTRS Full-Text: Click to View [PDF Size: 777 KB]
Author: Feiveson, Alan H.; Fiedler, James; Lee, Stuart M. C.; Koslovsky, Matthew D.; Stenger, Michael B.; Platts, Steven H.
Abstract: Head-up tilt (HUT) tests often are used in research to measure orthostatic intolerance (OI)
(inability to appropriately control blood pressure while upright) in clinical populations and otherwise healthy individuals after interventions. Post-space flight orthostatic intolerance is a well-known phenomenon, and countermeasures to its development has been an active area of research at NASA. In the NASA HUT protocol, subjects lie horizontally on an automatic tilt table for baseline measurements before being raised to 80deg head-up tilt for a defined period of time or until signs or symptoms of presyncope ensues (light-headedness, nausea, dizziness, sweating, weakness or fainting). Multiple measures are collected to evaluate the cardiovascular system's ability to respond appropriately to the orthostatic challenge. However if the intended duration of the HUT is short, the ability to detect changes in OI due to an intervention or its prevention by a countermeasure may be limited by a small number of failures to permit comparisons based on survival time alone. Thus, the time-trajectory of the cardiovascular data becomes an important additional source of information. In particular, we will show how various measures of trajectory variability can effectively augment survival analysis for the assessment of OI in a joint model when high censoring rates are present.
Publication Year: 2018Document Type: PreprintReport/Patent Number: JSC-E-DAA-TN51782Date Acquired: Apr 06, 2018
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