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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 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Ir(hkl) Surface Electrochemistry in a Nonadsorbing Acidic Medium

The fundamental properties of electrochemical materials depend on the multiple and often complex interactions between electrode surface sites and electrolyte species at the electrochemical interface. Despite Iridium use in electrolyzer systems, much of its surface electrochemistry remains underexplored. This study investigates the surface electrochemistry of Ir(111), Ir(100), and Ir(110) surfaces in acidic media. Using cyclic voltammetry and CO charge displacement experiments, we establish the charge states and adsorbate coverages as a function of the electrode potential, revealing the presence of hydrogen and hydroxyl co-adsorption at low potentials on (111), and almost no coverage of H ad on (110) facet. In situ Shell Isolated Nanoparticle Enhanced Raman Spectroscopy experiments provide direct evidence of the formation of key adsorbate species, such as hydrogen, hydroxyl, and oxygen, but most importantly, their interactions with interfacial water, confirmed by Density Functional Theory calculations. Our findings highlight the role of co-adsorption and interspecies interactions, with microkinetic adsorption voltammetry simulations corroborating the influence of lateral interactions on adsorption dynamics, particularly for Ir(100) where the OHad formation occurs as a sharp adsorption/desorption current. Our results underscores the importance of interfacial water and hydrogen bonding networks in shaping the electrochemical behavior on Ir surfaces, refining our baseline understanding of the Ir surface electrochemistry necessary for the development of advanced Ir-based electrochemical materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Ultranarrow bright single-photon emitters in diamond with strong broadband phonon decoupling

Single-photon emitters are fundamental building blocks for quantum information processing, communication and sensing. However, unwanted interactions with bulk phonons in their host environment strongly limit their coherence and controllability. We report single color centers in nanodiamonds that are strongly and comprehensively decoupled from the bulk phononic environment. The color centers feature record-narrow linewidths down to 0.3 nm at room temperature and stable, bright emission, exceeding 10 Mcps in saturation. Notably, the bulk phonon sideband is almost entirely suppressed, revealing the presence of a single localized vibrational mode outside the diamond phonon band. Our observations and simulations point towards a unique mechanism for phonon decoupling in common wide-gap materials, based on a strongly radiative orbital transition coupled to a localized vibrational mode. The new color center enables qualitatively higher performance for applications in quantum networks and nanoscale sensing, and the exploration of new physical resources associated with vibrational states.

Sahoo, Swetapadma [ORNL]↗
DOE OSTI2019

Planetary magnetic field control of ion escape from weakly magnetized planets

ABSTRACT Intrinsic magnetic fields have long been thought to shield planets from atmospheric erosion via stellar winds; however, the influence of the plasma environment on atmospheric escape is complex. Here we study the influence of a weak intrinsic dipolar planetary magnetic field on the plasma environment and subsequent ion escape from a Mars-sized planet in a global three-dimensional hybrid simulation. We find that increasing the strength of a planet’s magnetic field enhances ion escape until the magnetic dipole’s standoff distance reaches the induced magnetosphere boundary. After this point increasing the planetary magnetic field begins to inhibit ion escape. This reflects a balance between shielding of the Southern hemisphere from ‘misaligned’ ion pickup forces and trapping of escaping ions by an equatorial plasmasphere. Thus, the planetary magnetic field associated with the peak ion escape rate is critically dependent on the stellar wind pressure. Where possible we have fit power laws for the variation of fundamental parameters (escape rate, escape power, polar cap opening angle, and effective interaction area) with magnetic field, and assessed upper and lower limits for the relationships.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Effects of renormalon scheme and perturbative scale choices on determinations of the strong coupling from e + e − event shapes

We study the role of renormalon cancellation schemes and perturbative scale choices in extractions of the strong coupling constant α s ( m Z ) and the leading nonperturbative shift parameter Ω 1 from resummed predictions of the e + e − event shape thrust. We calculate the thrust distribution to N L 3 L ′ resummed accuracy in soft-collinear effective theory (SCET) matched to the fixed-order O ( α s 2 ) prediction, and perform a new high-statistics computation of the O ( α s 3 ) matching in , although we do not include the latter in our final α s fits due to some observed systematics that require further investigation. We are primarily interested in testing the phenomenological impact sourced from varying amongst three renormalon cancellation schemes and two sets of perturbative scale profile choices. We then perform a global fit to available data spanning center-of-mass energies between 35–207 GeV in each scenario. Relevant subsets of our results are consistent with prior SCET-based extractions of α s ( m Z ) , but we are also led to a number of novel observations. Notably, we find that the combined effect of altering the renormalon cancellation scheme and profile parameters can lead to few-percent-level impacts on the extracted values in the α s − Ω 1 plane, indicating a potentially important systematic theory uncertainty that should be accounted for. We also observe that fits performed over windows dominated by dijet events are typically of a higher quality than those that extend into the far tails of the distributions, possibly motivating future fits focused more heavily in this region. Finally, we discuss how different estimates of the three-loop soft matching coefficient c S ˜ 3 can also lead to measurable changes in the fitted { α s , Ω 1 } values. Published by the American Physical Society 2024

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Measurement of tritium penetration through concrete material covered by various paints coating

The present study aims at obtaining fundamental data on tritium migration in porous materials, which include soaking effect, interaction between tritium and cement paste coated with paints and transient tritium sorption in porous cement. The amounts of tritium penetrated into or released from cement paste with epoxy and urethane paint coatings were measured. The tritium penetration amounts were increased with the HTO (tritiated water) exposure time. Time to achieve a saturated value of tritium sorption was more than 60 days for cement paste coated with epoxy paint and with urethane paint, while that for cement paste without any paint coating took 2 days to achieve it. The effect of tritium permeation reduction by the epoxy paint was higher than that of the urethane. Although their paint coatings were effective for reduction of tritium penetration through the cement paste which was exposed to HTO for a short period, it was found that the amount of tritium trapped in the paints became large for a long period. Tritium penetration rates were estimated by an analysis of one-dimensional diffusion in the axial direction of a thickness of a sample. Obtained data were helpful for evaluation of tritium contamination and decontamination. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

High Pressure Synthesis of New Magnets, Featuring Diamagnetic Sources of Anisotropy

Permanent magnets are the functional component of electric motors and generators found in numerous renewable energy applications spanning from regenerative brakes to wind turbines. Magnets that generate higher magnetic flux per volume are central to improved energy generation in these applications. To develop a new class of permanent magnets while retaining the properties conferred by rare-earth elements, a fundamentally different approach is required. We hypothesize that by engendering a covalent interaction between two elements, it will be possible to interact the two components of a magnetic moment—spin and orbital angular momentum—from two separate atoms to form a complete magnetic moment. This seed project focuses on the scale up of the compound FeBi 2 , which was initially synthesized in our laboratory. Scale up approaches include slow decompression, alternate synthetic routes, and using fabrication approaches to more intimately mix the precursor elements. We also pursued the synthesis of new phases in the Mn-Bi system targeted to create new magnetic materials. In our initial experiments we decompressed FeBi 2 down to 2.9 GPa, demonstrating a kinetic stability to the phase that enabled it to be recovered to an order of magnitude lower pressure than that needed to synthesize it (30 GPa). Our goal is to recover this exciting material to ambient pressures so that we can isolate samples for detailed physical properties measurements. We have undertaken three distinct approaches toward that goal, which we summarize below. Our two most notable results are the formation of a quenchable phase through antimony doping of FeBi 2 , and the development of a new approach to preparing samples for diamond anvil cell syntheses.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Basic Energy Sciences Roundtable: Opportunities for Basic Research for Next-Generation Quantum Systems

For decades, scientists have predicted that devices based on “quantum phenomena” will be able to store and manipulate information to provide radical new approaches for computing, communication, and sensing. However, only recently have quantum phenomena been incorporated into technologies for next-generation computers, sensors, and detectors that demonstrate performance characteristics rivaling those of their conventional counterparts. These devices clearly demonstrate the enormous potential for future quantum-based technologies. The novel quantum device capabilities currently envisioned include enhanced resolution in imaging, sensors, and detectors; advanced cryptography for more secure communication; and significantly larger computational capabilities at speeds far greater than those possible in classical computing. However, realizing these advances requires a detailed understanding of how quantum systems (including quantum materials or assemblies of trapped ions and electrons) behave, accurate knowledge of how to integrate the components into complex systems, and precise control of the structures. In this context, creating and controlling quantum states within molecules and materials offer exciting scientific opportunities for fundamental research, as well as for enabling next-generation quantum-based technologies. Numerous questions remain, ranging from how quantum interactions may enable innovation through the creation of novel quantum systems, to how these new quantum technologies can advance our understanding of matter and chemistry at the most fundamental levels. To address these questions and identify priority research opportunities (PROs), the US Department of Energy (DOE) Office of Basic Energy Sciences (BES) convened a roundtable of experts in quantum materials and quantum systems encompassing the fields of physics, chemistry, materials synthesis science, device engineering, detector technology, and atomic-scale characterization techniques. This group of experimentalists and theorists met on October 30–31, 2017, to explore scientific research opportunities in this rapidly moving field, in which BES support can play a key role in advancing and utilizing quantum information science (QIS). The goals of this roundtable were to define the unique roles for BES in this active research field and to provide input on future research directions, forming the basis for a coordinated, long-term research effort that will enable major advances in quantum-based science and technology. BES is uniquely positioned to advance this field because of its long history of fundamental research support for both materials and chemical sciences, along with its construction and operation of world-class scientific user facilities. Fundamental research in this area is strongly coupled to DOE efforts in scientific computing, high-energy physics, and accelerator/detector research and related to activities in “Beyond Moore’s Law” computing, next-generation semiconductor materials, and exascale computing.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1981

Development of a direct experimental test for any violation of the equivalence principle by the weak interaction

Violation of the equivalence principle by the weak interaction is tested. Any variation of the weak interaction coupling constant with gravitational potential, i.e., a spatial variation of the fundamental constants is investigated. The level of sensitivity required for such a measurement is estimated on the basis of the size of a change in the gravitational potential which is accessible. The alpha particle spectrum is analyzed, and the counting rate was improved by a factor of approximately 100.

Parker, P. D. M.↗
NASA NTRS1985

Study of photon emission by electron capture during solar nuclei acceleration, 1: Temperature-dependent cross section for charge changing processes

The study of charge changing cross sections of fast ions colliding with matter provides the fundamental basis for the analysis of the charge states produced in such interactions. Given the high degree of complexity of the phenomena, there is no theoretical treatment able to give a comprehensive description. In fact, the involved processes are very dependent on the basic parameters of the projectile, such as velocity charge state, and atomic number, and on the target parameters, the physical state (molecular, atomic or ionized matter) and density. The target velocity, may have also incidence on the process, through the temperature of the traversed medium. In addition, multiple electron transfer in single collisions intrincates more the phenomena. Though, in simplified cases, such as protons moving through atomic hydrogen, considerable agreement has been obtained between theory and experiments However, in general the available theoretical approaches have only limited validity in restricted regions of the basic parameters. Since most measurements of charge changing cross sections are performed in atomic matter at ambient temperature, models are commonly based on the assumption of targets at rest, however at Astrophysical scales, temperature displays a wide range in atomic and ionized matter. Therefore, due to the lack of experimental data , an attempt is made here to quantify temperature dependent cross sections on basis to somewhat arbitrary, but physically reasonable assumptions.

Perez-Peraza, J.↗
NASA NTRS1984

ISEE-3 distant geotail results

The ISEE-3 spacecraft spent most of 1983 in the geomagnetic tail, between 60 and 240 earth radii. This extended mission phase has provided an opportunity to study the effects of the solar wind-magnetosphere interaction in previously unexplored downstream regions. Analyses have been conducted concerning such fundamental questions as the nature and structure of the distant tail, the role played by the tail in magnetospheric substorms, and the possibility of processes that lead to the heating and energization of the ambient plasma. Determinations have already been made on the very high plasmasheet velocities, the two-lobe structure of the tail, and the penetration of the IMF into the tail.

Tsurutani, B. T.↗
NASA NTRS1986

Leading-edge vortex research: Some nonplanar concepts and current challenges

Some background information is provided for the Vortex Flow Aerodynamics Conference and that current slender wing airplanes do not use variable leading edge geometry to improve transonic drag polar is shown. Highlights of some of the initial studies combining wing camber, or flaps, with vortex flow are presented. Current vortex flap studies were reviewed to show that there is a large subsonic data base and that transonic and supersonic generic studies have begun. There is a need for validated flow field solvers to calculate vortex/shock interactions at transonic and supersonic speeds. Many important research opportunities exist for fundamental vortex flow investigations and for designing advanced fighter concepts.

Campbell, J. F.↗
NASA NTRS1988

Design guide: Designing and building high voltage power supplies, volume 2

This report contains an accumulation of publications and analyses aimed at developing guidelines for improving both high voltage and low voltage power supplies for the U.S. Air Force systems command. It is the intent of the report to supply good design and manufacturing techniques for the packaging and the building of high quality, reliable, long-life power supplies. These data are based on the wealth of engineering practices established by design and manufacturing engineers. The contents are: Fundamentals of Insulation: Gases, Liquid Dielectrics, Solid Insulation; Environment: Pressure, Particulates, Environmental Interactions with Space Power Systems, Surface Charging, System Design Criteria; Configuration and Design Data: Designs, Transients, Grounding and Bonding, Thermal Control; Materials and Processes: Insulation, Processes, Process Variables; Manufacturing: Yield, Government and Industrial Survey, Analysis, Problem Areas and Suggested Solutions, Designs That Have Worked in High Voltage Equipment, Manufacturing Summary; and Tests: Performance, Insulation Tests, Materials Testing, Component and Equipment Tests, Performance Testing, Facility and Environment, Accelerated Life Test; Maintenance and Repair: Maintenance, Test Sets, Pilots and Crewmen, Air Logistic Centers, Design Problem Recommendations.

W G Dunbar↗
NASA NTRS1989

Numerical simulation of nonlinear development of instability waves

The nonlinear interactions of high amplitude instability waves in turbulent jets are described. In plane shear layers Riley and Metcalf (1980) and Monkewitz (1987) have shown that these interactions are dependent, among other parameters, on the phase-difference between the two instability waves. Therefore, here researchers consider the nonlinear development of both the amplitudes and the phase of the instability waves. The development of these waves are also coupled with the development of the mean flow and the background turbulence. In formulating this model it is assumed that each of the flow components can be characterized by conservation equations supplemented by closure models. Results for the interactions between the two instability waves under high-amplitude forcing at fundamental and subharmonic frequencies are presented here. Qualitative agreements are found between the present predictions and available experimental data.

Mankbadi, Reda R.↗
NASA NTRS1991

Probabilistic simulation of the human factor in structural reliability

Many structural failures have occasionally been attributed to human factors in engineering design, analyses maintenance, and fabrication processes. Every facet of the engineering process is heavily governed by human factors and the degree of uncertainty associated with them. Factors such as societal, physical, professional, psychological, and many others introduce uncertainties that significantly influence the reliability of human performance. Quantifying human factors and associated uncertainties in structural reliability require: (1) identification of the fundamental factors that influence human performance, and (2) models to describe the interaction of these factors. An approach is being developed to quantify the uncertainties associated with the human performance. This approach consists of a multi factor model in conjunction with direct Monte-Carlo simulation.

Shah, Ashwin R.↗
NASA NTRS2000

Theory of Type 3 and Type 2 Solar Radio Emissions

The main features of some current theories of type III and type II bursts are outlined. Among the most common solar radio bursts, type III bursts are produced at frequencies of 10 kHz to a few GHz when electron beams are ejected from solar active regions, entering the corona and solar wind at typical speeds of 0.1c. These beams provide energy to generate Langmuir waves via a streaming instability. In the current stochastic-growth theory, Langmuir waves grow in clumps associated with random low-frequency density fluctuations, leading to the observed spiky waves. Nonlinear wave-wave interactions then lead to secondary emission of observable radio waves near the fundamental and harmonic of the plasma frequency. Subsequent scattering processes modify the dynamic radio spectra, while back-reaction of Langmuir waves on the beam causes it to fluctuate about a state of marginal stability. Theories based on these ideas can account for the observed properties of type III bursts, including the in situ waves and the dynamic spectra of the radiation. Type 11 bursts are associated with shock waves propagating through the corona and interplanetary space and radiating from roughly 30 kHz to 1 GHz. Their basic emission mechanisms are believed to be similar to those of type III events and radiation from Earth's foreshock. However, several sub-classes of type II bursts may exist with different source regions and detailed characteristics. Theoretical models for type II bursts are briefly reviewed, focusing on a model with emission from a foreshock region upstream of the shock for which observational evidence has just been reported.

Robinson, P. A.↗
NASA NTRS1999

Phoretic Force Measurement for Microparticles Under Microgravity Conditions

This theoretical and experimental investigation of the collisional interactions between gas molecules and solid and liquid surfaces of microparticles involves fundamental studies of the transfer of energy, mass and momentum between gas molecules and surfaces. The numerous applications include particle deposition on semiconductor surfaces and on surfaces in combustion processes, containerless processing, the production of nanophase materials, pigments and ceramic precursors, and pollution abatement technologies such as desulfurization of gaseous effluents from combustion processes. Of particular emphasis are the forces exerted on microparticles present in a nonuniform gas, that is, in gaseous surroundings involving temperature and concentration gradients. These so-called phoretic forces become the dominant forces when the gravitational force is diminished, and they are strongly dependent on the momentum transfer between gas molecules and the surface. The momentum transfer, in turn, depends on the gas and particle properties and the mean free path and kinetic energy of the gas molecules. The experimental program involves the particle levitation system shown. A micrometer size particle is held between two heat exchangers enclosed in a vacuum chamber by means of ac and dc electric fields. The ac field keeps the particle centered on the vertical axis of the chamber, and the dc field balances the gravitational force and the thermophoretic force. Some measurements of the thermophoretic force are presented in this paper.

Davis, E. J.↗
NASA NTRS2007

Characterization of Kevlar Using Raman Spectroscopy

This paper explores the characterization of Kevlar composite materials using Raman spectroscopy. The goal of the research is to develop and understand the Raman spectrum of Kevlar materials to provide a foundation for the development of nondestructive evaluation (NDE) technologies based on the interaction of laser light with the polymer Kevlar. The paper discusses the fundamental aspects of experimental characterization of the spectrum of Kevlar, including the effects of incident wavelength, polarization and laser power. The effects of environmental exposure of Kevlar materials on certain characteristics of its Raman spectrum are explored, as well as the effects of applied stress. This data may provide a foundation for the development of NDE technologies intended to detect the in-situ deterioration of Kevlar materials used for engineering applications that can later be extended to other materials such as carbon fiber composites.

Washer, Glenn↗
NASA NTRS2013

Solar and Space Physics: A Science for a Technological Society

From the interior of the Sun, to the upper atmosphere and near-space environment of Earth, and outward to a region far beyond Pluto where the Sun's influence wanes, advances during the past decade in space physics and solar physics the disciplines NASA refers to as heliophysics have yielded spectacular insights into the phenomena that affect our home in space. This report, from the National Research Council's (NRC's) Committee for a Decadal Strategy in Solar and Space Physics, is the second NRC decadal survey in heliophysics. Building on the research accomplishments realized over the past decade, the report presents a program of basic and applied research for the period 2013-2022 that will improve scientific understanding of the mechanisms that drive the Sun's activity and the fundamental physical processes underlying near-Earth plasma dynamics, determine the physical interactions of Earth's atmospheric layers in the context of the connected Sun-Earth system, and enhance greatly the capability to provide realistic and specific forecasts of Earth's space environment that will better serve the needs of society. Although the recommended program is directed primarily to NASA (Science Mission Directorate -- Heliophysics Division) and the National Science Foundation (NSF) (Directorate for Geosciences -- Atmospheric and Geospace Sciences) for action, the report also recommends actions by other federal agencies, especially the National Oceanic and Atmospheric Administration (NOAA) those parts of NOAA charged with the day-to-day (operational) forecast of space weather. In addition to the recommendations included in this summary, related recommendations are presented in the main text of the report.

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