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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Cryogenic Front-End ASICs for Low-Noise Readout of Charge Signals

This paper presents design details and measurement results of LArASIC, a front-end application specific integrated circuit (ASIC) designed for low-noise readout of charge signals generated in neutrino study experiments within liquid argon time projection chambers. LArASIC comprises of 16-channels of programmable charge amplification and pulse shaping stages that provide a voltage readout proportional to the input charge and was optimized for operation at liquid argon temperature, i.e., 89 K. The chip was fabricated in a 180 nm CMOS process. Measurements at liquid nitrogen temperature, i.e., 77 K, indicate that the channel outputs have high linearity (INL < 0.1%) within the operating range, an equivalent noise charge of 534 electrons for a peaking time of 1 µs and a detector capacitance of 150 pF, and a worst-case inter-channel cross-talk of 0.35%. The paper also presents design choices made in the process of migrating LArASIC to CHARMS, an ASIC to be fabricated in a 65 nm process that includes all features provided by LArASIC, along with additional digital programmability for improved robustness and flexibility. CHARMS is intended for use in future high-energy physics experiments that require high-resolution charge or light readout with shorter pulse peaking times.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Effects of charge exchange on the evaporative wind of HD 209458b

ABSTRACT The role of charge exchange in shaping exoplanet photoevaporation remains a topic of contention. Exchange of electrons between stellar wind protons from the exoplanet’s host star and neutral hydrogen from the planet’s wind has been proposed as a mechanism to create ‘energetic neutral atoms’ (ENAs), which could explain the high absorption line velocities observed in systems where mass-loss is occurring. In this paper, we present results from three-dimensional hydrodynamic simulations of the mass-loss of a planet similar to HD 209458b. We self-consistently launch a planetary wind by calculating the ionization and heating resulting from incident high-energy radiation, inject a stellar wind into the simulation, and allow electron exchange between the stellar and planetary winds. We predict the potential production of ENAs by the wind–wind interaction analytically, and then present the results of our simulations, which confirm the analytic limits. Within the limits of our hydrodynamic simulation, we find that charge exchange with the stellar wind properties examined here is unable to explain the absorption observed at high Doppler velocities.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1980

Formation of bowl-shaped craters

High-explosive charges are used to form, in several types of granular media, laboratory-scale examples of the bowl-shaped craters that are found to be the largest and simplest class of impact structure on planetary and lunar surfaces. High-speed films of the experiments yield crater growth rate and particle displacement data, including quantitative stress, strain, displacement, and velocity data. These results are compared with the particle displacement and velocity data from large explosion experiments which have produced bowl-shaped craters. A time-sequence description of large, bowl-shaped impact crater formation is developed from the results of these comparisons, as well as those of the morphological features and structural deformations of large explosions and impact craters.

Piekutowski, A. J.↗
NASA NTRS1967

Versatile analog pulse height computer performs real-time arithmetic operations

Multipurpose analog pulse height computer performs real-time arithmetic operations on relatively fast pulses. This computer can be used for identification of charged particles, pulse shape discrimination, division of signals from position sensitive detectors, and other on-line data reduction techniques.

Brenner, R.↗
NASA NTRS1972

Electrophoresis demonstration on Apollo 16

Free fluid electrophoresis, a process used to separate particulate species according to surface charge, size, or shape was suggested as a promising technique to utilize the near zero gravity condition of space. Fluid electrophoresis on earth is disturbed by gravity-induced thermal convection and sedimentation. An apparatus was developed to demonstrate the principle and possible problems of electrophoresis on Apollo 14 and the separation boundary between red and blue dye was photographed in space. The basic operating elements of the Apollo 14 unit were used for a second flight demonstration on Apollo 16. Polystyrene latex particles of two different sizes were used to simulate the electrophoresis of large biological particles. The particle bands in space were extremely stable compared to ground operation because convection in the fluid was negligible. Electrophoresis of the polystyrene latex particle groups according to size was accomplished although electro-osmosis in the flight apparatus prevented the clear separation of two particle bands.

Snyder, R. S.↗
NASA NTRS1984

Pyroelectric materials as electronic pulse detectors of ultraheavy nuclei

The design and testing of ultraheavy-nucleus pulse detectors based on pyroelectric materials are reported, extending the preliminary findings of Tuzzolino (1983) and Simpson and Tuzzolino (1983). Uranium-ion beams of about 240 MeV/u are detected by a 39.5-micron-thick Si detector, degraded to about 175 MeV/u by Al absorbers, and then strike 700-micron-thick polyvinylidene fluoride or 1000-micron-thick LiTaO3 pyroelectric samples. Both detector systems are connected to a coincidence circuit via charge-sensitive preamplifiers, shaping amplifiers with 30-microsec effective time constants, and electronic discriminators. Sample spectra are shown, and the pulse heights measured are found to agree with theoretical calculations to within a factor of about 2. The response of the pyroelectric materials is found to be unaffected by exposure to about 10 Mrad of 2-7-MeV/u heavy ion radiation. With further study and improvement of the detection sensitivity, devices of this type could be applied to large-area space measurements of low ultraheavy-ion fluxes.

Simpson, J. A.↗
NASA NTRS1994

Nonlinear dynamics of drops and bubbles and chaotic phenomena

Nonlinear phenomena associated with the dynamics of free drops and bubbles are investigated analytically, numerically and experimentally. Although newly developed levitation and measurement techniques have been implemented, the full experimental validation of theoretical predictions has been hindered by interfering artifacts associated with levitation in the Earth gravitational field. The low gravity environment of orbital space flight has been shown to provide a more quiescent environment which can be utilized to better match the idealized theoretical conditions. The research effort described in this paper is a closely coupled collaboration between predictive and guiding theoretical activities and a unique experimental program involving the ultrasonic and electrostatic levitation of single droplets and bubbles. The goal is to develop and to validate methods based on nonlinear dynamics for the understanding of the large amplitude oscillatory response of single drops and bubbles to both isotropic and asymmetric pressure stimuli. The first specific area on interest has been the resonant coupling between volume and shape oscillatory modes isolated gas or vapor bubbles in a liquid host. The result of multiple time-scale asymptotic treatment, combined with domain perturbation and bifurcation methods, has been the prediction of resonant and near-resonant coupling between volume and shape modes leading to stable as well as chaotic oscillations. Experimental investigations of the large amplitude shape oscillation modes of centimeter-size single bubbles trapped in water at 1 G and under reduced hydrostatic pressure, have suggested the possibility of a low gravity experiment to study the direct coupling between these low frequency shape modes and the volume pulsation, sound-radiating mode. The second subject of interest has involved numerical modeling, using the boundary integral method, of the large amplitude shape oscillations of charged and uncharged drops in the presence of a static or time-varying electric field. Theoretically predicted non linearity in the resonant frequency of the fundamental quadrupole mode has been verified by the accompanying experimental studies. Additional phenomena such as hysteresis in the frequency response of ultrasoncially levitated droplets in the presence of a time varying electric field, and mode coupling in the oscillations of ultrasonically modulated droplets, have also been uncovered. One of the results of this ground-based research has been the identification and characterization of phenomena strictly associated with the influence of the gravitational field. This has also allowed us to identify the specific requirements for potential microgravity investigations yielding new information not obtainable on Earth.

Trinh, Eugene H.↗
NASA NTRS2006

Solar Sails

The Solar Sail Propulsion investment area has been one of the three highest priorities within the In-Space Propulsion Technology (ISPT) Project. In the fall of 2003, the NASA Headquarters' Science Mission Directorate provided funding and direction to mature the technology as far as possible through ground research and development from TRL 3 to 6 in three years. A group of experts from government, industry, and academia convened in Huntsville, Alabama to define technology gaps between what was needed for science missions to the inner solar system and the current state of the art in ultra1ightweight materials and gossamer structure design. This activity set the roadmap for development. The centerpiece of the development would be the ground demonstration of scalable solar sail systems including masts, sails, deployment mechanisms, and attitude control hardware and software. In addition, new materials would be subjected to anticipated space environments to quantify effects and assure mission life. Also, because solar sails are huge structures, and it is not feasible to validate the technology by ground test at full scale, a multi-discipline effort was established to develop highly reliable analytical models to serve as mission assurance evidence in future flight program decision-making. Two separate contractor teams were chosen to develop the SSP System Ground Demonstrator (SGD). After a three month conceptual mission/system design phase, the teams developed a ten meter diameter pathfinder set of hardware and subjected it to thermal vacuum tests to compare analytically predicted structural behavior with measured characteristics. This process developed manufacturing and handling techniques and refined the basic design. In 2005, both contractor teams delivered 20 meter, four quadrant sail systems to the largest thermal vacuum chamber in the world in Plum Brook, Ohio, and repeated the tests. Also demonstrated was the deployment and articulation of attitude control mechanisms. In conjunction with these tests, the stowed sails were subjected to launch vibration and ascent vent tests. Other investments studied radiation effects on the solar sail materials, investigated spacecraft charging issues, developed shape measuring techniques and instruments, produced advanced trajectory modeling capabilities, and identified and resolved gossamer structure dynamics issues. Technology validation flight and application to a He1iophysics science mission is on the horizon.

Young, Roy↗
NASA NTRS2021

Capabilities and Performance of Juno’s Radio Science Instrumentation

The Juno Gravity Science Instrument is a radio science instrument onboard the Juno spacecraft, which entered orbit around Jupiter in 2016. The prime objective of the radio science investigation is to estimate the gravitational field of Jupiter from the Doppler shift on the radio link between the spacecraft and the Earth-based observing antennas of NASA’s Deep Space Network (DSN). The instrument is composed of a ground component at the DSN’s DSS-25 antenna, equipped with simultaneous dual X- and Ka-band transmitters and receivers, and a spacecraft component, which includes X- and Ka-band transponders to relay the transmitted signal back to Earth. The frequencies of these signals are measured using sensitive open-loop and closed-loop receivers of the DSN. Using the unique geometry of Juno’s orbit around Jupiter and the exquisite precision of the radio science instrumentation (~5-10 microns/sec one-way), the gravity field of Jupiter has been probed to unprecedented precision, allowing for discoveries of Jupiter’s core size and depth of the zonal winds. This precision is thanks to a detailed data processing and calibration techniques. An Advanced Water Vapor Radiometer measures the tropospheric delay and a linear combination X- and Ka-band links calibrates for Earth ionosphere, solar plasma, and Jovian plasma. Recent measurements probed the electron content inside Jupiter’s Io Plasma Torus, a doughnut-shaped ring of charged particles caught in Jupiter’s magnetosphere. Results from these measurements not only contributes to the scientific literature but also informs the performance of the instrument itself and can be used in future planning.

Oudrhiri, Kamal↗
NASA NTRSDate not supplied

Photovoltaic Investigation on the Lunar Surface (PILS): Design Considerations and Ground Testing

The PILS (Photovoltaic Investigation on the Lunar Surface) platform consists of flight demonstrations of multiple solar cell technologies that could be used for future lunar missions. It also includes a solar charging experiment to shape design considerations of high voltage solar arrays on the Moon that could power in-situ resource utilization systems and other lunar surface assets. This poster and conference proceedings describe the design considerations of the PILS platform and ground testing performed prior to spacecraft integration. The platform is expected to operate on the lunar surface at Lacus Mortis in late 2022.

photovoltaics↗
NASA NTRSDate not supplied

Photovoltaic Investigation on the Lunar Surface (PILS) – PV Testbed for Lunar Landers

The PILS (Photovoltaic Investigation on the Lunar Surface) platform provides an opportunity to test state of the art solar cell technologies on the lunar surface. The first PILS mission is scheduled to operate on the lunar surface at Lacus Mortis in late 2022 onboard the Astrobotic Peregrine lander. The platform, designed, built, and tested at the NASA Glenn Research Center, includes multiple solar cell technologies from various vendors that could be used for future lunar missions and a solar charging experiment to shape design considerations of high voltage solar arrays on the Moon. This presentation will describe the mission requirements, design considerations, and ground testing performed prior to spacecraft integration. Considerations for future PILS missions will also be discussed.

Solar power↗
DOE OSTI2021

Simulations of crack extensions in arc-shaped tension specimens of uncharged and hydrogen-charged 21-6-9 austenitic stainless steels using cohesive zone modeling with varying cohesive parameters

Crack extensions in uncharged and hydrogen-charged side-grooved A(T) specimens of conventionally forged 21-6-9 austenitic stainless steels are simulated using the cohesive zone modeling approach. Two-dimensional plane strain finite element analyses with fixed cohesive parameters are first conducted to fit the experimental load-displacement curves. Similar analyses using varying cohesive parameters as functions of the crack extension are then conducted to fit the experimental load-crack extension and crack extension-displacement curves. The computational results with varying cohesive parameters can fit very well the experimental data. The computational results also indicate that the average cohesive energy for the hydrogen-charged A(T) specimen is lower than that for the uncharged A(T) specimen.

42 ENGINEERING↗
NASA NTRS1980

Quasi-projection-operator calculation of inelastic resonances in He/-/ and Li

Feshbach resonances of electrons incident of He and Li(+) are calculated below the 3(S-3) target threshold by means of the inelastic quasi-projection-operator technique of Temkin and Bhatia (1972). A configuration-interaction-type wave function is employed with up to 46 configurations. The calculations reveal, with reasonable accuracy, all presently observed Feshbach resonances. The method does not reveal shape resonances, but, for isoelectronic systems with greater nuclear charge, it is argued that shape resonance should become less important. This is already apparent in the case of Li, for which the known resonances are calculated and higher resonances, for which there are as yet no experimental data, are predicted.

Wakid, S.↗
DOE OSTI2025

Impact of the LiPF6 Concentration on the Interfacial Charge Transfer and Fast-charging Capabilities of Lithium-Ion Batteries

Fast-charging lithium-ion batteries (LIB) demand optimized electrolyte formulations to balance ionic conductivity, viscosity, and interfacial charge transfer kinetics. This study examines how LiPF 6 concentration shapes solvation structure, desolvation energy, charge transfer activation energy, and solid electrolyte interphase (SEI) properties, which are critical for fast-charging performance. Using Raman spectroscopy, electrochemical cycling, X-ray photoelectron spectroscopy, and atomistic modeling, we analyze how varying LiPF 6 concentrations impact interfacial and bulk transport properties. Our findings show that increasing LiPF 6 concentration alters lithium solvation structures, reduces desolvation energy, and accelerates charge transfer at the electrode interface. Higher concentrations lower the activation energy for charge transfer and suppress excessive SEI growth, improving interfacial kinetics. However, concentrations above a certain threshold increase viscosity and reduce ionic conductivity, limiting transport efficiency. These results offer insights into electrolyte solvation and interfacial charge transfer mechanisms, providing guidelines for designing next-generation fast-charging LIB electrolytes with enhanced efficiency, stability, and longevity.

Son, Seoung-Bum [Argonne National Laboratory (ANL)↗
DOE OSTI2023

Implementation of a High-Speed Multichannel Data Acquisition System for Magnetic Diagnostics and Plasma Centroid Position Control in ISTTOK

In tokamak and other fusion devices, magnetic control is the main tool that allows to regulate the plasma current, position and shape; it is in charge of actuating the desired plasma current waveform, steering the plasma position to a given set point and maintain the plasma shape close to a prescribed plasma equilibrium. This work describes the application of several physics concepts and computational tools in order to obtain a novel optimal controller for the plasma centroid position, which has been implemented and tested in the real-time plasma control system at the ISTTOK tokamak. A key point for the development of the new control system was the installation of a recently upgraded hardware, that numerically integrates in real-time the magnetic probes signals.

poloidal field coils↗
DOE OSTI2025

Ca X ML: Chemistry‐informed machine learning explains mutual changes between protein conformations and calcium ions in calcium‐binding proteins using structural and topological features

Proteins' flexibility is a feature in communicating changes in cell signaling instigated by binding with secondary messengers, such as calcium ions, associated with the coordination of muscle contraction, neurotransmitter release, and gene expression. When binding with the disordered parts of a protein, calcium ions must balance their charge states with the shape of calcium-binding proteins and their versatile pool of partners depending on the circumstances they transmit. Accurately determining the ionic charges of those ions is essential for understanding their role in such processes. However, it is unclear whether the limited experimental data available can be effectively used to train models to accurately predict the charges of calcium-binding protein variants. Here, we developed a chemistry-informed, machine-learning algorithm that implements a game theoretic approach to explain the output of a machine-learning model without the prerequisite of an excessively large database for high-performance prediction of atomic charges. We used the ab initio electronic structure data representing calcium ions and the structures of the disordered segments of calcium-binding peptides with surrounding water molecules to train several explainable models. Network theory was used to extract the topological features of atomic interactions in the structurally complex data dictated by the coordination chemistry of a calcium ion, a potent indicator of its charge state in protein. Our design created a computational tool of Ca X ML, which provided a framework of explainable machine learning model to annotate ionic charges of calcium ions in calcium-binding proteins in response to the chemical changes in an environment. Our framework will provide new insights into protein design for engineering functionality based on the limited size of scientific data in a genome space.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗