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Results for “time of flight”

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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Product ion distributions using H 3 O + proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS): mechanisms, transmission effects, and instrument-to-instrument variability

Abstract. Proton-transfer-reaction mass spectrometry (PTR-MS) using hydronium ion (H3O+) ionization is widely used for the measurement of volatile organic compounds (VOCs) both indoors and outdoors. H3O+ ionization, as well as the associated chemistry in an ion–molecule reactor, is known to generate product ion distributions (PIDs) that include other product ions besides the proton-transfer product. We present a method, using gas-chromatography pre-separation, for quantifying PIDs from PTR-MS measurements of nearly 100 VOCs of different functional types including alcohols, ketones, aldehydes, acids, aromatics, organohalides, and alkenes. We characterize instrument configuration effects on PIDs and find that reactor reduced electric field strength (E/N), ion optic voltage gradients, and quadrupole settings have the strongest impact on measured PIDs. Through an interlaboratory comparison of PIDs measured from calibration cylinders, we characterized the variability of PID production from the same model of PTR-MS across seven participating laboratories. Product ion variability was generally smaller (e.g., < 20 %) for ions with larger contributions to the PIDs (e.g., > 0.30) but less predictable for product ions formed through O2+ and NO+ reactions. We present a publicly available library of H3O+ PTR-MS PIDs that will be updated periodically with user-provided data for the continued investigation into instrument-to-instrument variability of PIDs.

Link, Michael F. (ORCID:0000000218412455)↗
DOE OSTI2020

Tools to perform data reduction of time-of-flight data taken on BL4A (MagRef)—a Jupyter notebook approach

A collection of modules or tools to produce reflectivity profiles from data acquired with unpolarized and polarized neutron beams using the BL4A (MagRef) instrument at the Spallation Neutron Source. The Jupyter notebook approach offers transparency to the user on what is done with the data, and once the event mode data are stored as NumPy binary files empowers the user to perform the steps from their own laptop without the need for Mantid. The notebook offers two options for background subtraction, applies corrections for the wavelength dependence of the polarizer and flipper efficiencies, accounts for Zeeman energy splitting of the spin-flip channels, Qz-bins the data along contours of constant Qz, propagates errors and writes results in text format suitable for analysis with tools such as GenX.

Fitzsimmons, Michael [Oak Ridge Associated Univ., ↗
NASA NTRS1963

Lunar Flight Study Series: Volume 5. Trajectories in the Earth-Moon Space with Symmetrical Free Return Properties

An extensive investigation has been made of the characteristics of so-called "free return" trajectories. For the purposes of the study., these trajectories are defined as having certain symmetric properties which afford flight to the vicinity of the moon and return to earth without need for propulsion after the initial boost phase. The restricted three-body model for the earth-moon-probe system is used throughout. Two kinds of free return trajectories are shown to -exist and are studied. Of particular interest is the fact that for one kind of free return path, the largest inclination which can be achieved between the flight plane at periselenum and the plane of the moon's orbit about earth is about 10. 8 degrees while for the other kind of path the largest possible inclination is dependent on ·the radius at periselenum. In this case the inclination is limited to about 14 degrees or less for periselenum radius of 1938 km, but may be as great as 90 degrees with periselenum radius of 21150 km. Trajectories are also demonstrated which pass in front of the moon. These exhibit inclination behavior very much like that given by trajectories which go behind the moon. The injection velocity for these trajectories also changes only slightly from the circumlunar trajectories (less than 2 m/s for periselenum radius of 1938 km). However, the position of injection is changed considerably and the flight time may be increased by as much as five times that for circumlunar flight.

RETURN-TO-EARTH PHASE↗
NASA NTRS1971

Apollo Operations Handbook Lunar Module (LM 11 and Subsequent) Vol. 2 Operational Procedures

The Apollo Operations Handbook (AOH) is the primary means of documenting LM descriptions and procedures. The AOH is published in two separately bound volumes. This information is useful in support of program management, engineering, test, flight simulation, and real time flight support efforts. This volume contains crew operational procedures: normal, backup, abort, malfunction, and emergency. These procedures define the sequence of actions necessary for safe and efficient subsystem operation.

Source record↗
NASA NTRS1978

The Space Shuttle Orbiter approach and landing tests - A correlation of flight and predicted performance data

This paper represents the results of a program in which a flight test vehicle was flown for a limited number of flights. The vehicle was the Space Shuttle Orbiter. The total free flight time for the entire flight test program was less than half an hour. The flight regime tested represented only the approach and landing phase of the vehicle's planned flight capability. The program relied heavily on an extensive wind tunnel test program to predict the aerodynamic performance data over the complete flight range, as well as to predict data tolerances. During the flight test program, short maneuvers performed were to provide flight motion data. A data extraction program was developed to produce flight derived aerodynamic performance data in coefficient form from the motion data. The resultant flight test data was correlated with the predicted data and fell within the predicted data tolerances for all phases of the subsonic flight test regime, including ground effects.

Romere, P. O.↗
NASA NTRS1979

Effect of time dependent flight loads on JT9D-7 performance deterioration

The results of a modal transient analysis of the engine/aircraft system are presented. The response of the JT9D to analytically simulated vertical gusts and landings was predicted using a NASTRAN finite element mathematical model of the JT9D/747 propulsion system. The NASTRAN finite element model of the propulsion system included engine structural models of the fan, low/high pressure compressors, diffuser/turbine cases, and high/low pressure rotors, as well as nacelle models of the inlet cowl, tailcone, and wing pylon. The analysis conducted predicts that an insignificant level of JT9D-7 performance deterioration would occur due to a typical vertical gust encounter or a typical revenue service landing. Analysis of a high sink rate landing with a heavy fuel load indicates the possibility of local wear, however, the lack of an accurate dynamic rotor/seal interference model precludes an accurate quantitative evaluation of performance change for this once-per-airframe-life event.

Jay, A.↗
NASA NTRS1981

Effect of time-dependent flight loads on turbofan engine performance deterioration

An analytic evaluation of the dynamic effects of two flight load conditions of the JT9D-7/747 propulsion system is conducted. Predicted performance changes associated with a once-per-flight vertical gust and a typical revenue service landing are calculated. The predicted dynamic load effects on thrust specific fuel consumption are found to be negligible. The results indicate that the quasi-steady state approach to flight loads modeling is adequate to investigate the factors important to the deterioration process.

Lewis, B. L.↗
NASA NTRS1983

Time-of-flight anemometer for hot section applications

The design, construction and testing of laser anemometer configurations for Hot Section velocity measurements is considered. Optimizing the laser anemometer system necessarily included the data processing algorithms used. It is felt that the requirements here are too demanding for standard laser anemometer systems.

Edwards, R. V.↗
NASA NTRS1985

The four spot time-of-flight laser anemometer

The newly constructed, four-spot anemometer was shown to perform as predicted. The new anemometer's measurement region has the required characteristics: wide acceptance angle and high spatial selectivity to permit measurements in turbulent, hostile environments.

Wernet, Mark P.↗
NASA NTRS1992

A 4-spot time-of-flight anemometer for small centrifugal compressor velocity measurements

The application of laser anemometry techniques in turbomachinery facilities is a challenging dilemma requiring an anemometer system with special qualities. Here, we describe the use of a novel laser anemometry technique applied to a small 4.5 kg/s, 4:1 pressure ratio centrifugal compressor. Sample velocity profiles across the blade pitch are presented for a single location along the rotor. The results of the intra-blade passage velocity measurements will ultimately be used to verify CFD 3-D viscous code predictions.

Wernet, Mark P.↗
NASA NTRS2000

Reflectron Time-of-Flight Mass Spectrometer (REMAS) Instrumentation

The restricted mass and power budgets of landed science missions present a challenge to obtaining detailed analyses of planetary bodies. In situ studies, whether alone or as reconnaissance for sample return, must rely on highly miniaturized and autonomous instrumentation. Such devices must still produce useful data sets from a minimum of measurements. The great desire to understand the surfaces and interiors of planets, moons, and small bodies had driven the development of small, robotic techniques with ever-increasing capabilities. One of the most important goals on a surface mission is to study composition in many geological contexts. The mineralogical, molecular, elemental, and isotopic content of near-surface materials (regolith, rocks, soils, dust, etc.) at a variety of sites can complement broader imaging to describe the makeup and formative history of the body in question. Instruments that perform this site-to-site analysis must be highly transportable and work as a suite. For instance, a camera, microscope, spectrophotometer, and mass spectrometer can share several components and operate under a parallel command structure. Efficient use of multiple systems on a small rover has been demonstrated on the Mars Pathfinder mission.

Brinckerhoff, W. B.↗
NASA NTRS2002

Control Oriented Modeling and Validation of Aeroservoelastic Systems

Lightweight aircraft design emphasizes the reduction of structural weight to maximize aircraft efficiency and agility at the cost of increasing the likelihood of structural dynamic instabilities. To ensure flight safety, extensive flight testing and active structural servo control strategies are required to explore and expand the boundary of the flight envelope. Aeroservoelastic (ASE) models can provide online flight monitoring of dynamic instabilities to reduce flight time testing and increase flight safety. The success of ASE models is determined by the ability to take into account varying flight conditions and the possibility to perform flight monitoring under the presence of active structural servo control strategies. In this continued study, these aspects are addressed by developing specific methodologies and algorithms for control relevant robust identification and model validation of aeroservoelastic structures. The closed-loop model robust identification and model validation are based on a fractional model approach where the model uncertainties are characterized in a closed-loop relevant way.

Crowder, Marianne↗
NASA NTRS1992

Disbond Detection in Bonded Aluminum Joints Using Lamb Wave Amplitude and Time-of-Flight

In recent years, there was a need of developing efficient nondestructive integrity assessment techniques for large area laminate structures, such as detections of disbond, crack, and corrosion in fuselage of an aircraft. Together with the improving tomography and computer technologies, progress has been made in many fields in NDE towards a faster inspection. Ultrasonically, Lamb wave is considered to be a candidate for large area inspections based on its capability of propagating a relatively long distance in thin plates and its media-thickness-dependent propagation properties. Moreover, the occurence of disbonds, corrosion, and even cracks often results in reduction of effective thickness of a laminate. The idea is to assess the condition of a structure by sensing the response of propagating Lamb waves to these flaws over long path length. A series of tests in the sequence of disbond, corrosion, and crack have been done on various types of specimen to investigate the feasibility of this approach. This paper will present some of the test results for disbond detection on aluminum lap splice joints.

Sun, Keun J.↗