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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

A Spectral Atlas of the Nu(sub 12) Fundamental of (13)C(12)CH6 in the 12 Micron Region

The recent discovery of the minor isotopomer of ethane, (13)C(12)CH6, in the planetary atmospheres of Jupiter and Neptune, added ethane to the molecules which can be used to determine isotopic (12)C(12)C ratios for the jovian planets. The increased spectral resolution and coverage of the IR and far-IR instruments to be carried on the Cassini mission to Saturn and Titan may enable the detection of the minor isotopomer. Accurate frequency and cross-section measurements of the nu(sub 12) fundamental under controlled laboratory condition are important to interpret current and future planetary spectra. High resolution spectra of the minor isotopomer (13)C(12)CH6 have been recorded in the 12.2 micron region using the Kitt Peak Fourier Transform (FTS) and the Goddard Tunable Diode Laser spectrometer (TDL). In a global fit to 19 molecular constants in a symmetric top Hamiltonian, transition frequencies of the nu(sub 12) fundamental ranging up to J=35 and K=20 have been determined with a standard deviation of less than 0.0005 cm(exp -1). From selected line intensity measurements, a vibrational dipole moment for the nu(sub 12) fundamental has been derived. Observed and calculated spectra covering the region from 740 cm(exp -1) and to 910 cm(exp -1) are presented. A compilation of transition frequencies, line intensities, and lower state energies are included for general use in the astronomical community.

Weber, Mark↗
NASA NTRS1994

Fundamental and harmonic radiation in type III solar radio bursts

Type III solar radio bursts are investigated by modeling the propagation of the electron beam and the generation and subsequent propagation of waves to the observer. Predictions from this model are compared in detail with particle, Langmuir wave, and radio data from the International Sun Earth Explorer-3 (ISSE-3) spacecraft and with other observations to clarify the roles of fundamental and harmonic emission in type III radio bursts. Langmuir waves are seen only after the arrival of the beam, in accord with the standard theory. These waves persist after a positive beam slope is last resolved, implying that sporadic positive slopes persist for some time, unresolved but in accord with the predictions of stochastic growth theory. Local electromagnetic emission sets in only after Langmuir waves are seen, in accord with the standard theory, which relies on nonlinear processes involving Langmuir waves. In the events investigated here, fundamental radiation appears to dominate early in the event, followed and/or accompanied by harmonic radiation after the peak, with a long-lived tail of multiply scattered fundamental or harmonic emission extending long afterwards. These results are largely independent of, but generally consistent with, the conclusions of earlier works.

Robinson, P. A.↗
NASA NTRS1998

Real-Time X-Ray Transmission Microscopy for Fundamental Studies Solidification

High resolution real-time X-ray Transmission Microscopy, XTM, has been applied to obtain information fundamental to solidification of optically opaque metallic systems. We have previously reported the measurement of solute profile in the liquid, phase growth, and detailed solid-liquid interfacial morphology of aluminum based alloys with exposure times less than 2 seconds. Recent advances in XTM furnace design have provided an increase in real-time magnification (during solidification) for the XTM from 4OX to 16OX. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 5 micrometers. We have applied this system to study of the kinetics of formation and morphological evolution of secondary fibers and particles in Al-Bi monotectic alloys to observe a previously unreported velocity dependent thermo-capillary depletion mechanism for Bi rich liquid which can penetrate many fiber diameters into the solid-liquid interface. In this talk we will discuss application of the XTM to the study the fundamentals of monotectic and eutectic solidification, the enhancement of XTM data with precise solid liquid interfacial temperature and thermal gradient measurement techniques, and the application of this technology to the study of the fundamentals of solidification in microgravity,

Curreri, Peter A.↗
NASA NTRS2002

Variations in the Strength of the Infrared Forbidden 2328.2 cm-1 Fundamental of Solid N2 in Binary Mixtures

We present the 2335-2325 cm(exp -1) infrared spectra and band positions, profiles, and strengths (A values) of solid nitrogen and binary mixtures of N2 with other molecules at 12 K. The data demonstrate that the strength of the infrared forbidden N2 fundamental near 2328 cm(exp -1) is moderately enhanced in the presence of NH3, strongly enhanced in the presence of H2O and very strongly enhanced in the presence of CO2, but is not significantly affected by CO, CH4, or O2. The mechanisms for the enhancements in N2-NH3 and N2-H2O mixtures are fundamentally different from those proposed for N2-CO2 mixtures. In the first case, interactions involving hydrogen-bonding are likely the cause. In the latter, a resonant exchange between the N2 stretching fundamental and the O-18=C-12 asymmetric stretch of O-18C-12O-16 is indicated. The implications of these results for several astrophysical issues are briefly discussed.

Bernstein, Max P.↗
NASA NTRS1999

Variations in the strength of the infrared forbidden 2328.2 cm-1 fundamental of solid N2 in binary mixtures

We present the 2335-2325 cm-1 infrared spectra and band positions, profiles and strengths (A values) of solid nitrogen and binary mixtures of N2 with other molecules at 12 K. The data demonstrate that the strength of the infrared forbidden N2 fundamental near 2328 cm-1 is moderately enhanced in the presence of NH3, strongly enhanced in the presence of H2O and very strongly enhanced (by over a factor of 1000) in the presence of CO2, but is not significantly affected by CO, CH4, or O2. The mechanisms for the enhancements in N2-NH3 and N2-H2O mixtures are fundamentally different from those proposed for N2-CO2 mixtures. In the first case, interactions involving hydrogen-bonding are likely the cause. In the latter, a resonant exchange between the N2 stretching fundamental and the 18O = 12C asymmetric stretch of 18O12C16O is indicated. The implications of these results for several astrophysical issues are briefly discussed.

NASA Discipline Exobiology↗
NASA NTRS2003

Proceedings of the 2003 NASA/JPL Workshop on Fundamental Physics in Space

The 2003 Fundamental Physics workshop included presentations ranging from forces acting on RNA to properties of clouds of degenerate Fermi atoms, to techniques to probe for a added space-time dimensions, and to flight hardware for low temperature experiments, amongst others. Mark Lee from NASA Headquarters described the new strategic plan that NASA has developed under Administrator Sean O'Keefe's leadership. Mark explained that the Fundamental Physics community now needs to align its research program and the roadmap describing the long-term goals of the program with the NASA plan. Ulf Israelsson of JPL discussed how the rewrite of the roadmap will be implemented under the leadership of the Fundamental Physics Discipline Working Group (DWG). Nick Bigelow, chair of the DWG, outlined how investigators can contribute to the writing of the roadmap. Results of measurements on very cold clouds of Fermi atoms near a Feshbach resonance were described by three investigators. Also, new measurements relating to tests of Einstein equivalence were discussed. Investigators also described methods to test other aspects of Einstein's relativity theories.

Strayer, Don↗
NASA NTRS2013

Rovibrational Spectroscopic Constants and Fundamental Vibrational Frequencies for Isotopologues of Cyclic and Bent Singlet HC2N isomers

Through established, highly-accurate ab initio quartic force fields (QFFs), a complete set of fundamental vibrational frequencies, rotational constants, and rovibrational coupling and centrifugal distortion constants have been determined for both the cyclic 1(sup 1) 1A' and bent 2(sup 1)A' DCCN, H(C13)CCN, HC(C-13)N, and HCC(N-15) isotopologues of HCCN. Spectroscopic constants are computed for all isotopologues using second-order vibrational perturbation theory (VPT2), and the fundamental vibrational frequencies are computed with VPT2 and vibrational configuration interaction (VCI) theory. Agreement between VPT2 and VCI results is quite good with the fundamental vibrational frequencies of the bent isomer isotopologues in accord to within a 0.1 to 3.2 / cm range. Similar accuracies are present for the cyclic isomer isotopologues. The data generated here serve as a reference for astronomical observations of these closed-shell, highly-dipolar molecules using new, high-resolution telescopes and as reference for laboratory studies where isotopic labeling may lead to elucidation of the formation mechanism for the known interstellar molecule: X 3A0 HCCN.

molecular data↗
NASA NTRS2014

Driving an Active Vibration Balancer to Minimize Vibrations at the Fundamental and Harmonic Frequencies

Vibrations of a principal machine are reduced at the fundamental and harmonic frequencies by driving the drive motor of an active balancer with balancing signals at the fundamental and selected harmonics. Vibrations are sensed to provide a signal representing the mechanical vibrations. A balancing signal generator for the fundamental and for each selected harmonic processes the sensed vibration signal with adaptive filter algorithms of adaptive filters for each frequency to generate a balancing signal for each frequency. Reference inputs for each frequency are applied to the adaptive filter algorithms of each balancing signal generator at the frequency assigned to the generator. The harmonic balancing signals for all of the frequencies are summed and applied to drive the drive motor. The harmonic balancing signals drive the drive motor with a drive voltage component in opposition to the vibration at each frequency.

Holliday, Ezekiel S.↗
NASA NTRS2017

Plans and Preliminary Results of Fundamental Studies of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory

This paper describes plans and preliminary results for using the NASA Propulsion Systems Lab (PSL) to experimentally study the fundamental physics of ice-crystal ice accretion. NASA is evaluating whether this facility, in addition to full-engine and motor-driven-rig tests, can be used for more fundamental ice-accretion studies that simulate the different mixed-phase icing conditions along the core flow passage of a turbo-fan engine compressor. The data from such fundamental accretion tests will be used to help develop and validate models of the accretion process. This paper presents data from some preliminary testing performed in May 2015 which examined how a mixed-phase cloud could be generated at PSL using evaporative cooling in a warmer-than-freezing environment.

Ice-Crystal Ice Accretion↗
NASA NTRS2016

Plans and Preliminary Results of Fundamental Studies of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory

This presentation accompanies the paper titled Plans and Preliminary Results of Fundamental Studies of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory. NASA is evaluating whether PSL, in addition to full-engine and motor-driven-rig tests, can be used for more fundamental ice-accretion studies that simulate the different mixed-phase icing conditions along the core flow passage of a turbo-fan engine compressor. The data from such fundamental accretion tests will be used to help develop and validate models of the accretion process. This presentation (and accompanying paper) presents data from some preliminary testing performed in May 2015 which examined how a mixed-phase cloud could be generated at PSL using evaporative cooling in a warmer-than-freezing environment.

Ice-Crystal Ice Accretion↗
NASA NTRS2017

An Initial Study of the Fundamentals of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory

This presentation shows results from an initial study of the fundamental physics of ice-crystal ice accretion using the NASA Propulsion Systems Lab (PSL). Ice accretion due to the ingestion of ice-crystals is being attributed to numerous jet-engine power-loss events. The NASA PSL is an altitude jet-engine test facility which has recently added a capability to inject ice particles into the flow. NASA is evaluating whether this facility, in addition to full-engine and motor-driven-rig tests, can be used for more fundamental ice-accretion studies that simulate the different mixed-phase icing conditions along the core flow passage of a turbo-fan engine compressor. The data from such fundamental accretion tests will be used to help develop and validate models of the accretion process. The present study utilized a NACA0012 airfoil. The mixed-phase conditions were generated by partially freezing the liquid-water droplets ejected from the spray bars. This presentation shows data regarding (1) the freeze out characteristics of the cloud, (2) changes in aerothermal conditions due to the presence of the cloud, and (3) the ice accretion characteristics observed on the airfoil model. The primary variable in this test was the PSL plenum humidity which was systematically varied for two duct-exit-plane velocities (85 and 135 ms) as well as two particle size clouds (15 and 50 m MVDi). The observed clouds ranged from fully glaciated to fully liquid, where the liquid clouds were at least partially supercooled. The air total temperature decreased at the test section when the cloud was activated due to evaporation. The ice accretions observed ranged from sharp arrow-like accretions, characteristic of ice-crystal erosion, to cases with double-horn shapes, characteristic of supercooled water accretions.

upwind schemes↗
NASA NTRS2017

An Initial Study of the Fundamentals of Ice Crystal Icing Physics in the Nasa Propulsion Systems Laboratory

This paper presents results from an initial study of the fundamental physics of ice-crystal ice accretion using the NASA Propulsion Systems Lab (PSL). Ice accretion due to the ingestion of ice-crystals is being attributed to numerous jet-engine power-loss events. The NASA PSL is an altitude jet-engine test facility which has recently added a capability to inject ice particles into the flow. NASA is evaluating whether this facility, in addition to full-engine and motor-driven-rig tests, can be used for more fundamental ice-accretion studies that simulate the different mixed-phase icing conditions along the core flow passage of a turbo-fan engine compressor. The data from such fundamental accretion tests will be used to help develop and validate models of the accretion process. The present study utilized a NACA0012 airfoil. The mixed-phase conditions were generated by partially freezing the liquid-water droplets ejected from the spray bars. This paper presents data regarding (1) the freeze out characteristics of the cloud, (2) changes in aerothermal conditions due to the presence of the cloud, and (3) the ice accretion characteristics observed on the airfoil model. The primary variable in this test was the PSL plenum humidity which was systematically varied for two duct-exit-plane velocities (85 and 135 ms) as well as two particle size clouds (15 and 50 m MVDi). The observed clouds ranged from fully glaciated to fully liquid, where the liquid clouds were at least partially supercooled. The air total temperature decreased at the test section when the cloud was activated due to evaporation. The ice accretions observed ranged from sharp arrow-like accretions, characteristic of ice-crystal erosion, to cases with double-horn shapes, characteristic of supercooled water accretions.

Evaporative Cooling↗
NASA NTRS2014

Fundamental Property Requirements for Thermal and Mechanical Response Analysis of Thermal Protection Materials and Systems

Spacecraft that are designed to reenter the Earth's atmosphere, or enter the atmosphere of another planet, require Thermal Protection Systems (TPS) in order to survive the extreme thermal environments during the atmospheric flight. Analytical modeling of thermal and mechanical response is a fundamental aspect of the design of TPS and development of TPS materials. The analyses are used to understand the response of the materials and systems under representative environments. Performing these analyses, and evaluating the results, requires a variety of fundamental inputs, including: thermal and mechanical material properties; predicted or measured ground test and flight environments; and information about adjacent structure or attachments. We explain the nature of the analyses, highlight the essential fundamental data that are required, and describe the impact of the accuracy in the input data on the final results. We also describe the important priorities in material characterization testing in support of analyses.

Squire, Thomas↗
NASA NTRS2019

Short Course on Lithium-Ion Batteries: Fundamental Concepts, Battery Safety, and Modeling Techniques

When developing this course several years back I asked myself, "What do I think the TFAWS community needs to know about lithium-ion batteries and why should they care?" I think the answers to these questions can be boiled down to the following statements: 1. Lithium-ion (Li-ion) battery electrical performance and efficiency are heavily driven by thermal conditions. 2. Li-ion battery assemblies can experience single cell thermal runaway events which can lead to cell-to-cell propagation; these are thermally driven failure events that can be controlled with effective thermal management systems. 3. Knowledge of BOTH Li-ion battery fundamentals AND traditional thermal design principles are required to develop safe battery assemblies that are both gravimetrically and volumetrically optimized.This year the Short Course on Lithium-ion Batteries will be presented in a 2-part series. The first portion, "Fundamentals, Battery Safety, and Thermal Runaway," will focus on educating participants on the fundamental aspects of Li-ion batteries and on battery safety related topics (i.e. thermal runaway, cell-to-cell propagation, safe handling practices, et...). The second portion, "Practical Thermal Simulation Techniques," will provide participants with a real time demonstration of how to use Thermal Desktop to model of Li-ion battery assemblies. This part of the lesson will cover geometry simplification, mesh development, boundary conditions, and heat loads for both nominal operations (charge and discharge) and for thermal runaway events.

Walker, William↗
DOE OSTI2019

Probing the Fundamental Nature of Dark Matter with the Large Synoptic Survey Telescope

Astrophysical and cosmological observations currently provide the only robust, empirical measurements of dark matter. Future observations with Large Synoptic Survey Telescope (LSST) will provide necessary guidance for the experimental dark matter program. This white paper represents a community effort to summarize the science case for studying the fundamental physics of dark matter with LSST. We discuss how LSST will inform our understanding of the fundamental properties of dark matter, such as particle mass, self-interaction strength, non-gravitational couplings to the Standard Model, and compact object abundances. Additionally, we discuss the ways that LSST will complement other experiments to strengthen our understanding of the fundamental characteristics of dark matter. More information on the LSST dark matter effort can be found at https://lsstdarkmatter.github.io/ .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Prospects for fundamental physics with LISA

In this paper, which is of programmatic rather than quantitative nature, we aim to further delineate and sharpen the future potential of the LISA mission in the area of fundamental physics. Given the very broad range of topics that might be relevant to LISA,we present here a sample of what we view as particularly promising fundamental physics directions. We organize these directions through a “science-first” approach that allows us to classify how LISA data can inform theoretical physics in a variety of areas. For each of these theoretical physics classes, we identify the sources that are currently expected to provide the principal contribution to our knowledge, and the areas that need further development. Overall, the classification presented here should not be thought of as cast in stone, but rather as a fluid framework that is amenable to change with the flow of new insights in theoretical physics.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2012

ON THE VARIATIONS OF FUNDAMENTAL CONSTANTS AND ACTIVE GALACTIC NUCLEUS FEEDBACK IN THE QUASI-STELLAR OBJECT HOST GALAXY RXJ0911.4+0551 at z = 2.79

We report on sensitive observations of the CO(J = 7{yields}6) and C I({sup 3}P{sub 2} {yields} {sup 3}P{sub 1}) transitions in the z = 2.79 QSO host galaxy RXJ0911.4+0551 using the IRAM Plateau de Bure interferometer. Our extremely high signal-to-noise spectra combined with the narrow CO line width of this source (FWHM = 120 km s{sup -1}) allows us to estimate sensitive limits on the spacetime variations of the fundamental constants using two emission lines. Our observations show that the C I and CO line shapes are in good agreement with each other but that the C I line profile is of the order of 10% narrower, presumably due to the lower opacity in the latter line. Both lines show faint wings with velocities up to {+-}250 km s{sup -1}, indicative of a molecular outflow. As such, the data provide direct evidence for negative feedback in the molecular gas phase at high redshift. Our observations allow us to determine the observed frequencies of both transitions with so far unmatched accuracy at high redshift. The redshift difference between the CO and C I lines is sensitive to variations of {Delta}F/F with F = {alpha}{sup 2}/{mu} where {alpha} is the fine structure constant and {mu} is the electron-to-proton mass ratio. We find {Delta}F/F (6.9 {+-} 3.7) Multiplication-Sign 10{sup -6} at a look-back time of 11.3 Gyr, which, within the uncertainties, is consistent with no variations of the fundamental constants.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2012

CONSTRAINING FUNDAMENTAL CONSTANT EVOLUTION WITH H I AND OH LINES

We report deep Green Bank Telescope spectroscopy in the redshifted H I 21 cm and OH 18 cm lines from the z = 0.765 absorption system toward PMN J0134-0931. A comparison between the 'satellite' OH 18 cm line redshifts, or between the redshifts of the H I 21 cm and 'main' OH 18 cm lines, is sensitive to changes in different combinations of three fundamental constants, the fine structure constant {alpha}, the proton-electron mass ratio {mu} {identical_to} m{sub p} /m{sub e} , and the proton g-factor g{sub p} . We find that the satellite OH 18 cm lines are not perfectly conjugate, with both different line shapes and stronger 1612 MHz absorption than 1720 MHz emission. This implies that the satellite lines of this absorber are not suitable to probe fundamental constant evolution. A comparison between the redshifts of the H I 21 cm and OH 18 cm lines, via a multi-Gaussian fit, yields the strong constraint [{Delta}F/F] = [ - 5.2 {+-} 4.3] Multiplication-Sign 10{sup -6}, where F {identical_to} g{sub p} [{mu}{alpha}{sup 2}]{sup 1.57} and the error budget includes contributions from both statistical and systematic errors. We thus find no evidence for a change in the constants between z = 0.765 and the present epoch. Incorporating the constraint [{Delta}{mu}/{mu}] < 3.6 Multiplication-Sign 10{sup -7} from another absorber at a similar redshift and assuming that fractional changes in g{sub p} are much smaller than those in {alpha}, we obtain [{Delta}{alpha}/{alpha}] = (- 1.7 {+-} 1.4) Multiplication-Sign 10{sup -6} over a look-back time of 6.7 Gyr.

79 ASTRONOMY AND ASTROPHYSICS↗