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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 55 records · Page 3

Two-stage fan. 3: Data and performance with rotor tip casing treatment, uniform and distorted inlet flows

A two stage fan with a 1st-stage rotor design tip speed of 1450 ft/sec, a design pressure ratio of 2.8, and corrected flow of 184.2 lbm/sec was tested with axial skewed slots in the casings over the tips of both rotors. The variable stagger stators were set in the nominal positions. Casing treatment improved stall margin by nine percentage points at 70 percent speed but decreased stall margin, efficiency, and flow by small amounts at design speed. Treatment improved first stage performance at low speed only and decreased second stage performance at all operating conditions. Casing treatment did not affect the stall line with tip radially distorted flow but improved stall margin with circumferentially distorted flow. Casing treatment increased the attenuation for both types of inlet flow distortion.

Burger, G. D.↗

Aerodynamic characteristics of a small-scale straight and swept-back wing with knee-blown jet flaps

Two sting-mounted, 50.8 cm (20 in.) span, knee-blown, jet-flap models were tested in a large (2.1- by 2.5-m (7- by 10-ft) subsonic wind tunnel. A straight- and swept-wing model were tested with fixed flap deflection with various combinations of full-span leading-edge slats. The swept-wing model was also tested with wing tip extensions. Data were taken at angles-of-attack between 0 deg and 40 deg, at dynamic pressures between 143.6 N/sq m (3 lb/sq ft) and 239.4 N/sq m (5 lb/sq ft), and at Reynolds numbers (based on wing chord) ranging from 100,000 to 132,000. Jet flap momentum blowing coefficients up to 10 were used. Lift, drag, and pitching-moment coefficients, and exit flow profiles for the flap blowing are presented in graphical form without analysis.

Morehouse, G. G.↗

Development of a rotor wake-vortex model, volume 1

Certain empirical rotor wake and turbulence relationships were developed using existing low speed rotor wave data. A tip vortex model was developed by replacing the annulus wall with a row of image vortices. An axisymmetric turbulence spectrum model, developed in the context of rotor inflow turbulence, was adapted to predicting the turbulence spectrum of the stator gust upwash.

Majjigi, R. K.↗

A portable Ka-band front-end test package for beam-waveguide antenna performance evaluation. Part 2: Tests on the antenna

In part one of this article, a description was given of a Ka-band test package developed to enable testing of the Deep Space Station (DDS) 13 34-m beam-waveguide (BWG) antenna at 32 GHz. Test results were given for the Ka-band test package in an on-the-ground test configuration. This article is a companion article concerned with Ka-band test results for the test package in an on-the-antenna test configuration. Included are Ka-band zenith noise-temperature values, tipping-curve data, and subreflector test results obtained at the Cassegrain focal point, as well as at the final BWG focal point (located in a subterranean pedestal room). Test results show that, through the use of the Ka-band test package, the BWG antenna performance was successfully evaluated at Ka-band. The Ka-band test package operated well in all of the different antenna test configurations.

Otoshi, T. Y.↗

Active vibration damping of the Space Shuttle Remote Manipulator System

The feasibility of providing active damping augmentation of the Space Shuttle Remote Manipulator System (RMS) following normal payload-handling operations is investigated. The approach used in the analysis is described and the results from both linear and nonlinear performance analyses of candidate laws are presented, demonstrating that significant improvement in the RMS dynamic response can be achieved through active control using measured RMS tip acceleration data for feedback.

Scott, Michael A.↗

Active vibration damping of the Space Shuttle remote manipulator system

The feasibility of providing active damping augmentation of the Space Shuttle Remote Manipulator System (RMS) following normal payload handling operations is investigated. The approach used in the analysis is described, and the results for both linear and nonlinear performance analysis of candidate laws are presented, demonstrating that significant improvement in the RMS dynamic response can be achieved through active control using measured RMS tip acceleration data for feedback.

Scott, Michael A.↗

Development of flow distortions in a full-scale nacelle inlet at Mach numbers 0.63 and 1.6 to 2.0

The nature of flow-distortion development in the subsonic diffuser was determined for a typical full-scale axisymmetric nose inlet at Mach numbers to 2.0 and angles of attack to -8 degrees. Inlet design variables studied included 14 degrees and 17 degrees internalcowl lip angles conical compression surfaces with and without boundary-layer removal slots, and cone tip translation. Data presented include the inlet overall pressure recovery, mass flow, and distortion at the diffuser exit. Primary emphasis in the data, however, is placed on critical inlet operation, for which the flow distortion is traced from the inlet throat to the diffuser exit.

Piercy, Thomas G↗

A portable X-band front-end test package for beam-waveguide antenna performance evaluation. Part 2: Tests on the antenna

Results are given for an X-band (8.45 GHz) test package for testing the new 34-m beam-waveguide antenna at Goldstone in an 'on-the-antenna' configuration. Included are X-band zenith noise temperature values and tipping-curve data obtained at the Cassegrain focal point F1 as well as at the pedestal room focal point F3. Subreflector Z-defocus test results for both F1 and F3 are also presented. The X-band test package operated well in all of the different test configurations and exceeded expected performance.

Otoshi, T. Y.↗

Microtubules restrict plastid sedimentation in protonemata of the moss Ceratodon

Apical cells of protonemata of the moss Ceratodon purpureus are unusual among plant cells with sedimentation in that only some amyloplasts sediment and these do not fall completely to the bottom of vertical cells. To determine whether the cytoskeleton restricts plastid sedimentation, the effects of amiprophos-methyl (APM) and cytochalasin D (CD) on plastid position were quantified. APM treatments of 30-60 min increased the plastid sedimentation that is normally seen along the length of untreated or control cells. Longer APM treatments often resulted in more dramatic plastid sedimentation, and in some cases almost all plastids sedimented to the lowermost point in the cell. In contrast, the microfilament inhibitor CD did not affect longitudinal plastid sedimentation compared to untreated cells, although it did disturb or eliminate plastid zonation in the tip. These data suggest that microtubules restrict the sedimentation of plastids along the length of the cell and that microtubules are load-bearing for all the plastids in the apical cell. This demonstrates the importance of the cytoskeleton in maintaining organelle position and cell organization against the force of gravity.

Non-NASA Center↗

UAE6 - Wind Tunnel Tests Data - UAE6 - Sequence V - Raw Data

Sequence V: Tip Plate (F) This test sequence used an upwind, rigid turbine with a 0° cone angle. The wind speed ranged from 5 m/s to 25 m/s, and the yaw angle was held at 0°. The blade pitch angle was 3°. The rotor rotated at 72 RPM. Blade pressure measurements were collected. The five-hole probes were removed and the plugs were installed. Plastic tape 0.03-mm-thick was used to smooth the interface between the plugs and the blade. The teeter dampers were replaced with rigid links, and these two channels were flagged as not applicable by setting the measured values in the data file to –99999.99 Nm. The teeter link load cell was pre-tensioned to 40,000 N. During post-processing, the probe channels were set to read -99999.99. The standard tip blocks were replaced with a tip plate to simulate the effect of an undeployed tip-mounted aerodynamic brake as shown in Appendix A. Note that the blade radius was not changed during post-processing so the pressure tap locations are at the same radial location, but the reference to 30% represents 30% of 5.029 m, not 4.943 m. Throughout this report, references to the blade span are made for the 5.029- m radius, not the 4.943-m radius.

17 WIND ENERGY↗

Tip aerodynamics and acoustics test: A report and data survey

In a continuing effort to understand helicopter rotor tip aerodynamics and acoustics, a flight test was conducted by NASA Ames Research Center. The test was performed using the NASA White Cobra and a set of highly instrumented blades. All aspects of the flight test instrumentation and test procedures are explained. Additionally, complete data sets for selected test points are presented and analyzed. Because of the high volume of data acquired, only selected data points are presented. However, access to the entire data set is available to the researcher on request.

Cross, Jeffrey L.↗

SPRUCE Root Tip and Ectomycorrhizal Fungi Colonization Measurements from Ingrowth Cores, 2017

This data set contains root tip and ectomycorrhizal fungi colonization measurements taken from ingrowth cores from the SPRUCE experiment (Hanson et al. 2017) that were deployed during the 2017 growing season (2017-06 to 2017-10-01). This study explored the relationship between warming treatments and fine-root growth. Increased fine-root growth may increase root exudates and accelerate turnover, representing an underlying mechanism for peat decomposition through priming, as exudates provide a labile carbon source to the microbial community. Roots of two tree species were studied: an evergreen conifer Picea mariana (black spruce) and a deciduous conifer Larix laricina (tamarack). Measurements include root tips counts and densities by tree species and the abundance of ectomycorrhizal colonization on root tips. This dataset contains one data file in comma separate (.csv) format. Additional metadata are provided: one data dictionary and a file-level metadata file in comma separate (.csv) format and a user guide in PDF (*.pdf) format.

black spruce [Picea mariana]↗

Noise and wake structure measurements in a subsonic tip speed fan: Tabulation and plots of test data

Noise and wake structure measurements in a ducted fan were conducted. The tip speed was kept at subsonic levels. The anechoic platform used during the test is described. The following conditions are reported: (1) one third octave band analyses of the fan noise data, (2) narrow band analyses of the fan noise for selected test conditions, (3) narrow band sound power level data for all fan test conditions, and (4) velocity and air angle evaluation of blade wake data.

Magliozzi, B.↗

VSAERO analysis of tip planforms for the free-tip rotor

The results of a numerical analysis of two interacting lifting surfaces separated in the spanwise direction by a narrow gap are presented. The configuration consists of a semispan wing with the last 32 percent of the span structurally separated from the inboard section. The angle of attack of the outboard section is set independently from that of the inboard section. In the present study, the three-dimensional panel code VSAERO is used to perform the analysis. Computed values of tip surface lift and pitching moment coefficients are correlated with experimental data to determine the proper approach to model the gap region between the surfaces. Pitching moment data for various tip planforms are also presented to show how the variation of tip pitching moment with angle of attack may be increased easily in incompressible flow. Calculated three-dimensional characteristics in compressible flow at Mach numbers of 0.5 and 0.7 are presented for new tip planform designs. An analysis of sectional aerodynamic center shift as a function of Mach number is also included for a representative tip planform. It is also shown that the induced drag of the tip surface is reduced for negative incidence angles relative to the inboard section. The results indicate that this local drag reduction overcomes the associated increase in wing induced drag at high wing lift coefficients.

Martin, D. M.↗

The Field Guide to NASA’s Life Sciences Data Repositories

For over 30 years, NASA has invested in life sciences research both in space and on the ground. Data accessibility is an important tool for researchers, and NASA has committed to preserving this vital resource for ongoing use. The Life Sciences Data Archive’s multi-center collaboration between NASA’s Johnson Space Center, Ames Research Center, and Kennedy Space Center is geared toward preserving unique and high-value data from a wide variety of disciplines, data collection methods, and species within NASA’s Life Sciences Portal (NLSP). The data generated by the Human Research Program (HRP) require a systematic approach to data preservation that accounts for diverse data sources, formats, physical storage requirements, and security and privacy protections. This poster presentation will provide a guide to the repositories where the various types of human, non-human animal, plant, and microbial data NASA generates are archived and tips for navigating these data collections. Topics will include where different types of data, metadata, and biospecimens are archived or preserved, how the federated repositories work together as a data preservation ecosystem, and how researchers can access each repository’s collections.

Robert S Beaton↗

A Field Guide to NASA’s Life Sciences Data Repositories

For over 30 years, NASA has invested in life sciences research both in space and on the ground. Data accessibility is an important tool for researchers, and NASA has committed to preserving this vital resource for ongoing use. The Life Sciences Data Archive’s multi-center collaboration between NASA’s Johnson Space Center, Ames Research Center, and Kennedy Space Center is geared toward preserving unique and high-value data from a wide variety of disciplines, data collection methods, and species within NASA’s Life Sciences Portal (NLSP). The data generated by the Human Research Program (HRP) require a systematic approach to data preservation that accounts for diverse data sources, formats, physical storage requirements, and security and privacy protections. This poster presentation will provide a guide to the repositories where the various types of human, non-human animal, plant, and microbial data NASA generates are archived and tips for navigating these data collections. Topics will include where different types of data, metadata, and biospecimens are archived or preserved, how the federated repositories work together as a data preservation ecosystem, and how researchers can access each repository’s collections.

LSDA↗

Hybrid Machine Learning for Scanning Near-Field Optical Spectroscopy

The underlying physics behind an experimental observation often lacks a simple analytical description. This is especially the case for scanning probe microscopy techniques, where the interaction between the probe and the sample is nontrivial. Realistic modeling to include the details of the probe is always exponentially more difficult than its "spherical cow" counterparts. On the other hand, a well-trained artificial neural network based on real data can grasp the hidden correlation between the signal and sample properties. In this work, we show that, via a combination of model calculation and experimental data acquisition, a physics-infused hybrid neural network can predict the tip-sample interaction in the widely used scattering-type scanning near-field optical microscope. This hybrid network provides a long-sought solution for accurate extraction of material properties from tip-specific raw data. The methodology can be extended to other scanning probe microscopy techniques as well as other data-oriented physical problems in general.

36 MATERIALS SCIENCE↗

Measurements of DSD Second Moment Based on Laser Extinction

Using a technique recently developed for estimating the density of surface dust dispersed during a rocket landing, measuring the extinction of a laser passing through rain (or dust in the rocket case) yields an estimate of the 2nd moment of the particle cloud, and rainfall drop size distribution (DSD) in the terrestrial meteorological case. With the exception of disdrometers, instruments that measure rainfall make in direct measurements of the DSD. Most common of these instruments are the rainfall rate gauge measuring the 1 1/3 th moment, (when using a D(exp 2/3) dependency on terminal velocity). Instruments that scatter microwaves off of hydrometeors, such as the WSR-880, vertical wind profilers, and microwave disdrometers, measure the 6th moment of the DSD. By projecting a laser onto a target, changes in brightness of the laser spot against the target background during rain, yield a measurement of the DSD 2nd moment, using the Beer-Lambert law. In order to detect the laser attenuation within the 8-bit resolution of most camera image arrays, a minimum path length is required, depending on the intensity of the rainfall rate. For moderate to heavy rainfall, a laser path length of 100 m is sufficient to measure variations in optical extinction using a digital camera. A photo-detector could replace the camera, for automated installations. In order to spatially correlate the 2nd moment measurements to a collocated disdrometer or tipping bucket, the laser's beam path can be reflected multiple times using mirrors to restrict the spatial extent of the measurement. In cases where a disdrometer is not available, complete DSD estimates can be produced by parametric fitting of DSD model to the 2nd moment data in conjunction with tipping bucket data. In cases where a disdrometer is collocated, the laser extinction technique may yield a significant improvement to insitu disdrometer validation and calibration strategies

Lane, John E.↗