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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Extension of Miles Equation for Ring Baffle Damping Predictions to Small Slosh Amplitudes and Large Baffle Widths

The Miles equation has long been used to predict slosh damping in liquid propellant tanks due to ring baffles. The original work by Miles identifies defined limits to its range of application. Recent evaluations of the Space Launch System identified that the Core Stage baffle designs resulted in violating the limits of the application of the Miles equation. This paper describes the work conducted by NASA/MSFC to develop methods to predict slosh damping from ring baffles for conditions for which Miles equation is not applicable. For asymptotically small slosh amplitudes or conversely large baffle widths, an asymptotic expression for slosh damping was developed and calibrated using historical experimental sub-scale slosh damping data. For the parameter space that lies between region of applicability of the asymptotic expression and the Miles equation, Computational Fluid Dynamics simulations of slosh damping were used to develop an expression for slosh damping. The combined multi-regime slosh prediction methodology is shown to be smooth at regime boundaries and consistent with both sub-scale experimental slosh damping data and the results of validated Computational Fluid Dynamics predictions of slosh damping due to ring baffles.

West, Jeff↗
NASA NTRS2016

Cassini Ring Plane Crossings: Hypervelocity Impact Risks to Sun Sensor Assemblies

For both F/G and D-ring crossings: Probability of a penetration damage of the SSH (Sun Sensor Head) window glass is very low; Optical attenuation due to craters on the surface of the window glass caused by direct HVI (Hyper-Velocity Impact) by dust particle is estimated to be less than 1 percent; Optical attenuation due to secondary debris cloud generated by the disintegrated ring dust particles is estimated to be less than 1 percent. To better manage the Sun sensor damage risk during selected proximal orbit crossings, it is highly desirable to follow the contingency procedures mentioned in Section VII of the paper: Details of this contingency procedure are given in the paper entitled "Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings" authored by David M. Bates. Based on results of risk analyses documented in this work and contingency planning work described in the paper mentioned above, we judge that the proximal orbit campaign will be safe from the viewpoint of dust HVI hazard.

dust particles↗
NASA NTRS2018

Study of a Tricarbide Grooved Ring Fuel Element for Nuclear Thermal Propulsion

Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nu- clear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the operating temperature of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment. Results of experiments and associated analysis are desired densities with some success in material distribution and reaching a solid solution. Future work is needed to improve distribution of material, minimize oxidation during the milling process, and de ne a fabrication process that will serve for constructing grooved ring fuel rods for large system tests.

Taylor, Brian↗
NASA NTRS2018

Study of a Tricarbide Grooved Ring Fuel Element for Nuclear Thermal Propulsion

Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nuclear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the operating temperature of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment. Results of experiments and associated analysis are discussed. The authors demonstrated success in reaching desired densities with some success in material distribution and reaching a solid solution. Future work is needed to improve distribution of material, minimize oxidation during the milling process, and define a fabrication process that will serve for constructing grooved ring fuel rods for large system tests.

Taylor, Brian↗
NASA NTRS2017

Impact of Substorm Time O+ Outflow on Ring Current Enhancement

Energetic O+ ions (tens of keV) rapidly increase in the inner magnetosphere and contribute significantly to the ring current during substorms. Previously, two source regions of the energetic O+ ions have been proposed. The first one is the dayside polar region. Ions from the dayside polar region are transported to the lobe; then they are injected to the nightside plasma sheet during substorm expansion phase. The second one is the nightside aurora region. After the substorm onset, energetic O+ ions are extracted from the ionosphere with the auroral acceleration processes, and the O+ ions are directly supplied to the nightside plasma sheet. We investigated the relative importance of these two regions on supplying the energetic O+ ions in the inner magnetosphere. We performed a test particle simulation in global MHD electromagnetic fields. We obtained the following results. (1) During the substorm growth phase, O+ ions at tens of eV are extracted from the dayside polar region, resulting in the enhancement of the warm O+ ions (hundreds of eV) in the lobe. After the substorm onset, the warm O+ ions are nonadiabatically accelerated to tens of keV and injected to the inner magnetosphere. These O+ ions contribute to most of the O+ ring current. (2) O+ ions at less than a few keVs are supplied from the nightside aurora region to the plasma sheet. However, their contribution to the O+ ring current remains small. From the results, we concluded that the main source of the energetic O+ ions is the dayside polar region.

outflow↗
NASA NTRS2019

Co-orbital Asteroids as the Source of Venus's Zodiacal Dust Ring

Photometry from the Helios and STEREO spacecraft revealed regions of enhanced sky surface-brightness suggesting a narrow circumsolar ring of dust associated with Venus's orbit. We model this phenomenon by integrating the orbits of 10,000,000+ dust particles subject to gravitational and non-gravitational forces, considering several different kinds of plausible dust sources. We find that only particles from a hypothetical population of Venus co-orbital asteroids can produce enough signal in a narrow ring to match the observations. Previous works had suggested such objects would be dynamically unstable. However, we re-examined the stability of asteroids in 1:1 resonance with Venus and found that ~8% should survive for the age of the solar system, enough to supply the observed ring.

Pokorný, Petr↗
NASA NTRS2019

The Matter Beyond the Ring: The Recent Evolution of SN 1987A Observed by the Hubble Space Telescope

The nearby SN 1987A offers a spatially resolved view of the evolution of a young supernova (SN) remnant. Here we present recent Hubble Space Telescope imaging observations of SN 1987A, which we use to study the evolution of the ejecta, the circumstellar equatorial ring (ER), and the increasing emission from material outside the ER. We find that the inner ejecta have been brightening at a gradually slower rate and that the western side has been brighter than the eastern side since ∼7000 days. This is expected given that the X-rays from the ER are most likely powering the ejecta emission. At the same time, the optical emission from the ER continues to fade linearly with time. The ER is expanding at 680 ± 50 km s−1, which reflects the typical velocity of transmitted shocks in the dense hot spots. A dozen spots and a rim of diffuse Hα emission have appeared outside the ER since 9500 days. The new spots are more than an order of magnitude fainter than the spots in the ER and also fade faster. We show that the spots and diffuse emission outside the ER may be explained by fast ejecta interacting with high-latitude material that extends from the ER toward the outer rings. Further observations of this emission will make it possible to determine the detailed geometry of the high-latitude material and provide insight into the formation of the rings and the mass-loss history of the progenitor.

Core-collapse supernova↗
NASA NTRSDate not supplied

Parabolic Flights in Support of the Ring-Sheared Drop (RSD) Module Aboard the ISS

The Ring-Sheared Drop module was conceived as a centimeter-scale, containerless biochemical reactor to study shearing flow at gas-liquid interfaces without complications associated with solid walls. The drop is constrained by a thin, stationary contact ring in one hemisphere and sheared by the steady rotation of another ring in the other hemisphere. The original experiment considers a 2.5 cm diameter drop of human insulin solution in order to examine the formation of amyloid fibrils without wall nucleation. Shear-induced amyloidogenesis is of wide interest due to the pathogenic role amyloid proteins play in diseases such as Alzheimer's, Parkinson's, prion diseases, and type-2 diabetes. Pinning full-scale drops of native protein solutions - prior to any fibrillization - was challenging and required a collaborative effort. In this talk we report on laboratory experiments, multiphase CFD simulations, and several parabolic flights to find strategies that are effective for constraining large drops of protein in microgravity.

Amir Hirsa↗
NASA NTRS2021

A Ring Accelerator? Unusual Jet Dynamics in the IceCube Candidate PKS 1502+106

On 2019/07/30.86853 UT, IceCube detected a high-energy astrophysical neutrino can-didate. The Flat Spectrum Radio Quasar PKS 1502+106 is located within the 50 percent uncertainty region of the event. Our analysis of 15 GHz Very Long Baseline Ar-ray (VLBA) and astrometric 8 GHz VLBA data, in a time span prior and after theIceCube event, reveals evidence for a radio ring structure which develops with time.Several arc-structures evolve perpendicular to the jet ridge line. We find evidence forprecession of a curved jet based on kinematic modelling and a periodicity analysis.An outflowing broad line region (BLR) based on the C IV line emission (Sloan Dig-ital Sky Survey, SDSS) is found. We attribute the atypical ring to an interaction ofthe precessing jet with the outflowing material.We discuss our findings in thecontext of a spine-sheath scenario where the ring reveals the sheath andits interaction with the surroundings (NLR clouds).We find that the radioemission is correlated with theγ-ray emission, with radio lagging theγ-rays. Basedon theγ-ray variability timescale, we constrain theγ-ray emission zone to the BLR(30-200rg) and within the jet launching region. We discuss that the outflowing BLRprovides the external radiation field forγ-ray production via external Compton scat-tering.The neutrino is most likely produced by proton-proton interactionin the blazar zone (beyond the BLR), enabled by episodic encounters ofthe jet with dense clouds, i.e. some molecular cloud in the NLR.

S Britzen↗
NASA NTRS2022

Explicit IMF By-Dependence of Energetic Protons and the Ring Current

The most important parameter driving the solar wind-magnetosphere interaction is the southward (Bz) component of the interplanetary magnetic field (IMF). While the dawn-dusk (By) component of the IMF is also known to play an important role, its effects are usually assumed to be independent of its sign. Here we demonstrate for the first time a seasonally varying, explicit IMF By-dependence of the ring current and Dst index. Using satellite observations and a global magnetohydrodynamic model coupled with a ring current model, we show that for a fixed level of solar wind driving the flux of energetic magnetospheric protons and the growth-rate of the ring current are greater for By < 0 (By > 0) than for By > 0 (By < 0) in Northern Hemisphere summer (winter). While the physical mechanism of this explicit By-effect is not yet fully understood, our results suggest that IMF By modulates magnetospheric convection and plasma transport in the inner magnetosphere.

L Holappa↗
NASA NTRS2022

Stormtime Ring Current Heating of the Ionosphere and Plasmasphere

The energy deposition from ring current ions into the high density “cold” plasma of the ionosphere and plasmasphere is analyzed, based on a Comprehensive Inner Magnetosphere-Ionosphere simulation of the 2015 October 7 storm. In addition, the Naval Research Laboratory Sami3 is Also a Model of the Ionosphere ionosphere/plasmasphere code is used to simulate the effect of Coulomb-collision heating of plasmasphere and ionosphere electrons by ring current ions. We find that, during stormtime peaks in the Dst index, energy is deposited at altitudes as low as 100 km. Heating along the entirety of any given field line, both in the ionosphere and plasmasphere, contributes to increased temperatures in the ionosphere F layer and inner magnetosphere and to subsequent cold O + outflows. However, relative to the heating of the plasmasphere, the direct heating of the ionosphere by ring current ions produces only small effects. Qualitative model-data agreement on the N + /O + density ratio is consistent with the hypothesis that these outflows are driven by thermal forcing.

J. Krall↗
DOE OSTI2020

Comprehensive Symmetric-Hybrid ring design for pEDM experiment at below $10^{-29}e\cdot$cm

A concise demonstrative summary of the Symmetric Hybrid ring design for the storage ring proton electric dipole moment experiment is presented. Critical issues such as lattice design, background electrical fields,geometrical phase, general relativity, spin coherence time and polarimeter systematics are presented. Overall, we find that with the currently proposed design iteration, systematic error sources are reduced by orders of magnitude and that the ring alignment requirements are within the currently available technology.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Linear Modelling from Betatron Phase Measurements at the Fermilab Recycler NOvA ring

Utilizing the measurement of coherent betatron oscillation phase has emerged as fast and precise approach for identifying and rectifying errors in implementing a desired lattice in CESR (Cornell Electron Storage Ring). One key advantage of betatron phase measurement over β measurement is its sensitivity to phase variations between widely separated points. This methodology has been successfully implemented for the Recycler NOvA Ring at Fermilab, with the adoption of TAO (Tool for Accelerator Optics) developed by Cornell University. By employing this technique, a linear model of the Recycler NOvA ring is established, enabling the correction of quadrupole errors.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

System and method for sub-wavelength detection for jetting-based additive manufacturing using a split ring resonator probe

The present disclosure relates to a system for detecting and analyzing droplets of feedstock material being ejected from an additive manufacturing device. The system makes use of a split ring resonator (SRR) probe including a ring element having a gap, with the gap being positioned adjacent a path of travel of the droplets of feedstock material. An excitation signal source is used for supplying an excitation signal to the SRR probe. An analyzer analyzes signals generated by the SRR probe in response to perturbations in an electric field generated by the SRR probe as the droplets of feedstock material pass the ring element. The signals are indicative of dimensions of the droplets of feedstock material.

Mukherjee, Saptarshi↗
DOE OSTI2024

Low-alpha Operation of the Iota Storage Ring

Operation with ultra-low momentum-compaction factor (alpha) is a desirable capability for many storage rings and synchrotron radiation sources. For example, low-alpha lattices are commonly used to produce picosecond bunches for the generation of coherent THz radiation and are the basis of a number of conceptual designs for EUV generation via steady-state microbunching (SSMB). Achieving ultra-low alpha requires not only a high-level of stability in the linear optics but also flexible control of higher-order compaction terms. Operation with lower momentum-compaction lattices has recently been investigated at the IOTA storage ring at Fermilab. A procedure for lowering the ring compaction using the linear optics along with compensations from the higher-order magnets was developed with the aid of a model, and an experimental technique for measuring the momentum compaction was developed. The lowest momentum compaction achieved during the available run-time was $3.4\times10^{-4}$, around 15 times lower than previously operated. These feasibility studies ensure an improved experimental understanding of the IOTA optics and potentially will enable new research programs at the facility.

43 PARTICLE ACCELERATORS↗
NASA NTRS1993

Particle Motion Near a Ring

The dynamics of a particle moving near a classical ring is studied under a Hill-type approximation. A classical ring is comprised of particles of equal mass arranged symmetrically about a massive central body, the particles having a uniform rotation rate.

ring stability ring growth Hill's Equation of moti↗
DOE OSTI2024

Reactive Processing of Furan‐Based Monomers via Frontal Ring‐Opening Metathesis Polymerization for High Performance Materials

Frontal ring-opening metathesis polymerization (FROMP) presents an energy-efficient approach to produce high-performance polymers, typically utilizing norbornene derivatives from Diels–Alder reactions. This study broadens the monomer repertoire for FROMP, incorporating the cycloaddition product of biosourced furan compounds and benzyne, namely 1,4-dihydro-1,4-epoxynaphthalene (HEN) derivatives. A computational screening of Diels–Alder products is conducted, selecting products with resistance to retro-Diels–Alder but also sufficient ring strain to facilitate FROMP. The experiments reveal that varying substituents both modulate the FROMP kinetics and enable the creation of thermoplastic materials characterized by different thermomechanical properties. Moreover, HEN-based crosslinkers are designed to enhance the resulting thermomechanical properties at high temperatures (>200 °C). The versatility of such materials is demonstrated through direct ink writing (DIW) to rapidly produce 3D structures without the need for printed supports. This research significantly extends the range of monomers suitable for FROMP, furthering efficient production of high-performance polymeric materials.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Simulation studies of a full-ring, CZT SPECT system for whole-body imaging of 99m Tc and 177 Lu

Single photon emission computed tomography (SPECT) is an imaging modality that has demonstrated its utility in a number of clinical indications. Despite this progress, a high sensitivity, high spatial resolution, multi-tracer SPECT with a large field of view suitable for whole-body imaging of a broad range of radiotracers for theranostics is not available. With the goal of filling this technological gap, we have designed a cadmium zinc telluride (CZT) full-ring SPECT scanner instrumented with a broad-energy tungsten collimator. The final purpose is to provide a multi-tracer solution for brain and whole-body imaging. Our static SPECT does not rely on the dual- and the triple-head rotational SPECT standard paradigm, enabling a larger effective area in each scan to increase the sensitivity. We provide a demonstration of the performance of our design using a realistic model of our detector with simulated body-sized phantoms filled with 99m Tc and 177 Lu. Our SPECT design can resolve 7.9 mm rods for 99m Tc (140 keV) and 9.5 mm for 177 Lu (208 keV) in a hot-rod Derenzo phantom with a 3-min exposure and reach an image contrast of 78% for 99m Tc and 57% for 177 Lu using the NEMA IQ phantom with a 6-min exposure. Our modified scatter correction shows an improved contrast-recovery ratio compared to a standard correction. In this paper, we demonstrate the good performance of our design for whole-body imaging purposes. This adds to our previous demonstration of improved qualitative and quantitative 99m Tc imaging of brain perfusion and 123 I imaging of dopamine transport with respect to state-of-the-art NaI dual-head cameras. We show that our design provides similar IQ and contrast to the commercial full-ring SPECT VERITON for 99m Tc. Regarding 177 Lu imaging of the 208 keV emissions, our design provides similar contrast to that of other state-of-the-art SPECTs with a significant reduction in exposure. In conclusion, the high sensitivity and extended energy range up to 250 keV makes our SPECT design a promising alternative for clinical imaging and theranostics of emerging radionuclides.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗