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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 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Hypervelocity impact effects on solar cells

One of the space hazards of concern is the problem of natural matter and space debris impacting spacecraft. This phenomena has been studied since the early sixties and a methodology has been established to determine the relative abundance of meteoroids as a function of mass. As the mass decreases, the probability of suffering collisions increases, resulting in a constant bombardment from particles in the sub-micron range. The composition of this 'cosmic dust' is primarily Fe, Ni, Al, Mg, Na, Ca, Cr, H, O, and Mn. In addition to mechanical damage, impact velocities greater than 5 k m/sec can produce shock induced ionization effects with resultant surface charging and complex chemical interactions. The upper limit of the velocity distribution for these particles is on the order of 70 km/sec. The purpose of this work was to subject samples from solar power arrays to debris flux typical of what would be encountered in space, and measure the degradation of the panels after impact.

Rose, M. Frank↗
NASA NTRS1994

Neutral hydrogen in the solar wind acceleration region

Observation of solar Ly alpha radiation scattered by coronal neutral hydrogen atoms can be used to investigate the acceleration region of the solar wind. In this paper we focus on the use of these observations to study Alfven waves, which can accelerate the solar wind plasma to flow speeds observed in high-speed streams if their amplitude at the coronal base is 20 km/s or larger. The wave amplitude is then larger than the proton thermal speed in the outer corona, so that the mean proton speed (averaged over a wave period) is significantly larger than the proton thermal speed. For low-frequency wave the hydrogen atoms follow the proton motion in the waves, while for higher frequencies the protons move relative to the neutrals. Nevertheless, in the higher frequency case, the rates for charge exchange and recombination are high enough to broaden the velocity distribution function of neutral hydrogen. Both the wave motion of the hydrogen atoms in low-frequency Alfven waves and the 'heating' by higher frequency waves lead to a broadening of the scattered solar Ly alpha line. For coronal base amplitues of 20 km/s, the line broadening increases with heliocentric distance beyond 4-5 solar radii.

Olsen, Espen Lyngdal↗
NASA NTRS1997

Doppler Global Velocimeter Development for the Large Wind Tunnels at Ames Research Center

Development of an optical, laser-based flow-field measurement technique for large wind tunnels is described. The technique uses laser sheet illumination and charged coupled device detectors to rapidly measure flow-field velocity distributions over large planar regions of the flow. Sample measurements are presented that illustrate the capability of the technique. An analysis of measurement uncertainty, which focuses on the random component of uncertainty, shows that precision uncertainty is not dependent on the measured velocity magnitude. For a single-image measurement, the analysis predicts a precision uncertainty of +/-5 m/s. When multiple images are averaged, this uncertainty is shown to decrease. For an average of 100 images, for example, the analysis shows that a precision uncertainty of +/-0.5 m/s can be expected. Sample applications show that vectors aligned with an orthogonal coordinate system are difficult to measure directly. An algebraic transformation is presented which converts measured vectors to the desired orthogonal components. Uncertainty propagation is then used to show how the uncertainty propagates from the direct measurements to the orthogonal components. For a typical forward-scatter viewing geometry, the propagation analysis predicts precision uncertainties of +/-4, +/-7, and +/-6 m/s, respectively, for the U, V, and W components at 68% confidence.

Reinath, Michael S.↗
NASA NTRS2006

Mission Operations Insights

The mission description Polar Operational Environmental Satellites (POES): I) Collect and disseminate worldwide meteorological and environmental data: a) Provide day and night information (AVHRR): 1) cloud cover distribution and type; 2) cloud top temperature; 3) Moisture patterns and ice/snow melt. b) Provide vertical temperature and moisture profiles of atmospheres (HIRS, AMSU, MHS. c) Measure global ozone distribution and solar UV radiation (SBUV). d) Measure proton, electro, and charged particle density to provide solar storm warnings (SEM). d) Collect environmental data (DCS): 1) Stationary platforms in remote locations; 2) Free floating platforms on buoys, balloons, migratory animals. II) Provide Search and Rescue capabilities (SARR, SARP): a) Detection and relay of distress signals. b) Has saved thousands of lives around the world.

Littman, Dave↗
NASA NTRS2010

Behavioral Health and Performance (BHP) Standing Review Panel (SRP) Final Report

The first meeting of the Behavioral Health and Performance (BHP) Standing Review Panel (SRP) was held in Houston, TX on November 1-3, 2009. Our task was to assess the Integrated Research Plan (IRP) related to the fields covered in the SRP charge (see section VIII). Having considered and discussed the extensive materials distributed prior to the meeting, and the highly informative briefings by the NASA BHP Human Research Program (HRP) personnel during the site visit, the SRP agreed that the IRP is comprehensive and was developed carefully. Question and answer periods with the presenters were particularly productive and helpful to the SRP. The presenters' willingness to share information and positive responses to the SRP's suggestions were greatly appreciated. Although the IRP and related documents are impressive, the SRP does have a number of recommendations regarding both the overall plan and its component parts.

Suedfeld, Peter↗
DOE OSTI2022

E-transit-bench: simulation platform for analyzing electric public transit bus fleet operations

When electrified transit systems make grid aware choices, improved social welfare is achieved by reducing grid stress, reducing system loss, and minimizing power quality issues. Electrifying transit fleet has numerous challenges like non availability of buses during charging, varying charging costs and so on, that are related the electric grid behavior. However, transit systems do not have access to the information about the co-evolution of the grid's power flow and therefore cannot account for the power grid's needs in its day-to-day operation. In this paper we propose a framework of transportation-grid co-simulation, analyzing the spatio-temporal interaction between the transit operations with electric buses and the power distribution grid. Real-world data for a day's traffic from Chattanooga city's transit system is simulated in SUMO and integrated with a realistic distribution grid simulation (using GridLAB-D) to understand the grid impact due to transit electrification. Charging information is obtained from the transportation simulation to feed into grid simulation to assess the impact of charging. We also discuss the impact to the grid with higher degree of transit electrification that further necessitates such an integrated transportation-grid co-simulation to operate the integrated system optimally. Our future work includes extending the platform for optimizing the charging and trip assignment operations.

Sen, Rishav↗
DOE OSTI2026

A fresh perspective on the role of band bending, and related contributors, in light-driven production of electricity and chemicals

It is widely known that semiconductor-based solar energy conversion could power our planet. This is in part because high-quality semiconductor structures are unrivalled in their ability to separate photogenerated electrons and holes. One effective approach to achieving this photoinduced charge separation relies on a phenomenon known as “band bending”. But details to justify why band bending results in photoinduced charge separation are more complex than often appreciated. This underappreciation is an impediment to the rational, hypothesis-driven design of next-generation approaches to solar energy conversion. Herein we show, by means of derivations rooted in physical chemistry, that several phenomena – not just band bending – can facilitate photoinduced charge separation, and that each is influenced by nonequilibrium species concentration and a parameter, such as diffusion coefficient or rate coefficient, that introduces dynamics. To help visualize the impact of each phenomenon, we introduce plots that depict their contributions as free energy, force, flux, force constant, and rate. We reveal that spatial dopant distributions that define band bending are predictors of initial photogenerated species transport rates. But charge separation alone does not guarantee high-efficiency operation. A photogenerated change in energy that is freely available to do useful work is also essential, and is strongly dependent on semiconductor optical properties and reaction kinetics. Notably, this information reveals that specificity of interfacial chemical reactions – even when they are not preceded by charge separation elsewhere – can result in efficient solar energy conversion. We expect that this tutorial will guide researchers in their pursuit to uncover new mechanisms for light to perform useful work.

14 SOLAR ENERGY↗
DOE OSTI2024

Development of a Hardware-in-The-Loop Testbed for a Decentralized, Data-Driven Electric Vehicle Charging Control Algorithm

This study presents the design of an electric vehicle (EV)-grid integration (EVGI) hardware test-bed to implement smart EV charging algorithms. Here, the proposed test-bed also allows to create different grid events via flexible integration of other power hardware (e.g., controllable loads and battery energy storage systems) and test their impacts on EV charging. The design uses a real-time digital simulator to realize a complex distribution grid model with primary and secondary networks. A grid simulator physically realizes the selected nodes of the simulated grid to power an actual EV, forming a hardware-in-the-loop (HIL) test setup. The EV-grid integration is demonstrated based on the custom hardware and software implementation of the J1772 charging protocol using dSPACE MicroLabBox, operating as a custom EV Supply Equipment (EVSE). The HIL test-bed features a novel testing platform for accurate implementation and analysis of scalable charging algorithms. To this end, a data-driven, decentralized, model-free charging controller based on the Additive Increase and Multiplicative Decrease (AIMD) algorithm is presented and validated on an EV using the HIL test-bed. We tested the proposed algorithm under various case studies, and presented a comparison study with an existing droop-based, decentralized charging solution. The results showed that the EV successfully performed charging commands generated by the EVSE and regulated its charging power to effectively reduce the system loading caused by high EV penetration.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2025

Understanding baryon stopping at the BNL Relativistic Heavy Ion Collider top energies

The nucleon exhibits a rich internal structure governed by quantum chromodynamics (QCD), where its electric charge arises from valence quarks, while its spin and mass emerge from complex interactions among valence quarks, sea (anti)quarks, and gluons. At the advent of QCD, an alternative hypothesis emerged suggesting, at high energies, the transport of a nucleon's baryon number could be traced by a nonperturbative configuration of gluon fields connecting its three valence quarks, forming a 𝑌-shaped topology known as the gluon junction. Recent measurements by the STAR experiment are compatible with this scenario. In light of these measurements, this study aims to explore the mechanisms of baryon transport in high-energy nuclear collisions using the pythia-8 framework, which incorporates a state-of-the-art hadronization model with advanced color flow (CF) and color reconnection (CR) mechanisms that mimic signatures of a baryon junction. Within this model setup, we investigate (i) the rapidity slope of the net-baryon distributions in photon-included processes (𝛾 + 𝑝) and (ii) baryon over charge transport in the isobaric (Ru + Ru and Zr + Zr) collisions. Our study highlights the importance of the CF and CR mechanisms in pythia-8, which play a crucial role in baryon transport. The results show that the CF and CR schemes significantly affect the isobaric baryon-to-charge ratio, leading to different predictions for baryon stopping and underscoring the need to account for CF and CR effects in comparisons with experimental measurements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Ultrafast probing of charge transfer dynamics with an XUV free-electron laser

We study charge transfer in dissociating molecules of 2-iodopropane (C 3 H 7 I) in a UV pump – XUV probe regime at the SACLA free-electron laser. Signatures of charge transfer from the recently dissociated iodine atom to the neutral propyl radical are observed in recorded 3D ion momentum distributions. This signature has evaded observation in previous related experiments. Detailed analysis of these signatures allows the identification of a region of internuclear separation where charge transfer occurs.

74 ATOMIC AND MOLECULAR PHYSICS↗
NASA NTRS1980

Three dimensional space charge model for large high voltage satellites

High power solar arrays for satellite power systems with dimensions of kilometers, and with tens of kilovolts distributed over their surface face many plasma interaction problems that must be properly anticipated. In most cases, the effects cannot be adequately modeled without detailed knowledge of the plasma sheath structure and space charge effects. Two computer programs were developed to provide fully self consistent plasma sheath models in three dimensions as a result of efforts to model the experimental plasma sheath studies at NASA/JSC. Preliminary results indicate that for the conditions considered, the Child-Langmuir diode theory can provide a useful estimate of the plasma sheath thickness. The limitations of this conclusion are discussed. Some of the models presented exhibit the strong ion focusing observed in the JSC experiments.

Cooks, D.↗
DOE OSTI2024

Revealing the three-dimensional structure of microbunched plasma-wakefield-accelerated electron beams

Abstract Plasma wakefield accelerators use tabletop equipment to produce relativistic femtosecond electron bunches. Optical and X-ray diagnostics have established that their charge concentrates within a micrometre-sized volume, but its sub-micrometre internal distribution, which critically influences gain in free-electron lasers or particle yield in colliders, has proven elusive to characterize. Here, by simultaneously imaging different wavelengths of coherent optical transition radiation that a laser-wakefield-accelerated electron bunch generates when exiting a metal foil, we reveal the structure of the coherently radiating component of bunch charge. The key features of the images are shown to uniquely correlate with how plasma electrons injected into the wake: by a plasma-density discontinuity, by ionizing high- Z gas-target dopants or by uncontrolled laser–plasma dynamics. With additional input from the electron spectra, spatially averaged coherent optical transition radiation spectra and particle-in-cell simulations, we reconstruct coherent three-dimensional charge structures. The results demonstrate an essential metrology for next-generation compact X-ray free-electron lasers driven by plasma-based accelerators.

43 PARTICLE ACCELERATORS↗
NASA NTRS2001

Iogenic Plasma and its Rotation-Driven Transport in Jupiter's Magnetosphere

Model calculations are reported for the Iogenic plasma source created by atomic oxygen and sulfur above Io's exobase in the corona and extended clouds (Outer Region). On a circumplanetary scale, two-dimensional distributions produced by integrating the proper three dimensional rate information for electron impact and charge exchange processes along the magnetic field lines are presented for the pickup ion rates, the net-mass and total-mass loading rates, the mass per unit magnetic flux rate, the pickup conductivity, the radial pickup current, and the net-energy loading rate for the plasma torus. All of the two-dimensional distributions are highly peaked at Io's location and hence highly asymmetric about Jupiter. The Iogenic plasma source is also calculated on a much smaller near-Io scale to investigate the structure of the highly peak rates centered about lo's instantaneous location. The Iogenic plasma source for the Inner Region (pickup rates produced below Io's exobase) is, however, expected to be the dominant source near lo for the formation of the plasma torus ribbon and to be a comparable source, if not a larger contributor, to the energy budget of the plasma torus, so as to provide the necessary power to sustain the plasma torus radiative loss rate.

Smyth, William H.↗
DOE OSTI2020

Design and Fabrication of the Mu2e Cryogenic Distribution System

The muon-to-electron conversion (Mu2e) experiment at Fermilab will be used to search for the charged lepton flavor-violating conversion of muons to electrons in the field of an atomic nucleus. The Mu2e experiment is currently in the design and construction stage and is expected to begin operations in 2022. The Mu2e experiment uses four large superconducting solenoid magnets including a Production Solenoid (PS), an Upstream and Downstream Transport Solenoid (TSu and TSd) and a Detector Solenoid (DS). This paper will focus on the cryogenic distribution system for these four solenoid magnets. Liquid helium will be supplied from two re-purposed Tevatron satellite refrigerators. A large cryogenic distribution box (DB) is located in the Mu2e building to distribute the required cryogens to each of the four solenoid magnets. Each solenoid magnet will have a dedicated transfer line and cryogenic feed box (FB). The solenoid magnets each require two liquid helium circuits and two liquid nitrogen circuits. The most unique feature about this cryogenic system is that the assemblies for the start of the superconducting portion of the power leads are mounted in feed boxes that are in the range of 23 m to 31 m away from the solenoid magnets. The cryogenic feed boxes are located remotely to provide protection from radiation damage and high magnetic fields. The power leads are NbTi superconducting cable stabilized with high conductivity aluminum. The 6061-T6 aluminum grade was selected for the transfer line piping so that the piping would thermally contract at the same rate as the power lead. A major concern for this transfer line is that a small helium leak could create an electric discharge arc due to the Paschen effect. This paper includes a description of the design features and testing done to ensure that the power leads are protected from the Paschen effect while still being adequately cooled to liquid helium temperatures.

43 PARTICLE ACCELERATORS↗
NASA NTRS1981

Preliminary comparison of material charging properties using single-energy and multienergy electron beams

Results of tests designed to compare the charging properties of spacecraft material under a monoenergetic beam and under a continuously distributed beam are summarized. In the test setup the electron source was mounted in the top of a cylindrical vacuum chamber. A sheet of 5-mil-thick Kapton was placed on an insulated metal substrate at the bottom of the vacuum chamber. The dc current arriving on the substrate was measured and a field meter measured the potential of the test sample. A retarding potential analyzer measured the energy spectrum of the incident electron beam. With the monoenergetic beam, the sample charged to 12 kV and electrical discharges occurred. With the multi-energy spectra the samples charged to only 6 kV and 4 kV, and no discharger were observed. In these experiments, no effort was made to duplicate the spectra occurring in space. The tests were intended to simply to compare spacecraft material charging properties using monoenergetic and continuous multi-energy beams.

Adamo, R. C.↗
DOE OSTI2021

An improved specimen preparation method for marine shallow gas-bearing sand sediments and its validations

Instabilities of shallow gas-charged seabed are potential geological hazards in ocean engineering. In practice, the conventional field sampling techniques failed to obtain undisturbed gas-bearing sediments from the seabed for laboratory mechanical testing because of sensitive gas exsolution and escape from sediments. However, preparation of representative remoulded gas-charged specimens is a challenging issue, because it is rather difficult to quantitatively control the gas content and obtain uniform distribution of gas bubbles within the specimen. Given the above problems, this work proposes a reliable approach to reconstitute the high-saturation specimen of gas-charged sediments in the laboratory by an improved multifunction integrated triaxial apparatus (MITA). This apparatus is developed based on an advanced stress path triaxial system by introducing a temperature-controlled system and a wave-monitoring system. The temperature-controlled system is used to accurately mimic the in situ environments of sediments in the seabed. The wave-monitoring system is utilized to identify exsolution point of free gas and examine the disturbance of gas to specimens during gas exsolution. The detailed procedure of gassy specimen preparation is introduced. Then, the quality of prepared specimens using our improved apparatus is validated by the high-resolution micro-X-ray computed tomography (μCT) scanning test, from which bubble occurrence and size distribution within the gassy sand specimen can be obtained; and preliminary mechanical tests on gassy sand specimens with various initial saturation degrees are performed. The proposed specimen preparation procedure succeeds in proving the postulated occurrence state of gas bubbles in coarse-grained sediments and accurately controlling the gas content.

58 GEOSCIENCES↗
DOE OSTI2025

EVSE DERMS Controls [SWR-26-010]

An MQTT (Message Queuing Telemetry Transport) and OCPP (Open Charge Point Protocol) based remote smart charging controller framework for AC Electric Vehicle Supply Equipments (EVSEs). The code in this repo allows for the National Laboratory of the Rockies (NLR) controls to interface with the real Distributed Energy Resource Management System (DERMS) and EVSEs in NLR's ESIF Optimization and Control Laboratory (OCL). Different charge management algorithms can be tested to determine which power allocation method is most effective with the overall goal of demonstrating clear and well documented test results as well as providing functional control algorithms which could be utilized to provide effective smart charge management (SCM) at EV charging stations. Different power allocation methods are programmed in lab_demo_controller.py and include allocation based on first come first served, equal sharing, state of charge (SOC), priority factors, and behind the meter control methods.

Panossian, Nadia [National Laboratory of the Rocki↗