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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 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Measurements of the ionization efficiency of protons in methane

The amount of energy released by a nuclear recoil ionizing the atoms of the active volume of detection appears “quenched” compared to an electron of the same kinetic energy. This different behavior in ionization between electrons and nuclei is described by the Ionization Quenching Factor (IQF) and it plays a crucial role in direct dark matter searches. For low kinetic energies (below 50 keV ), IQF measurements deviate significantly from common models used for theoretical predictions and simulations. We report measurements of the IQF for proton, an appropriate target for searches of Dark Matter candidates with a mass of approximately 1 GeV , with kinetic energies in between 2 keV and 13 keV in 100 mbar of methane. We used the Comimac facility in order to produce the motion of nuclei and electrons of controlled kinetic energy in the active volume, and a NEWS-G SPC to measure the deposited energy. The Comimac electrons are used as a reference to calibrate the detector with 7 energy points. A detailed study of systematic effects led to the final results well fitted by IQF (E K )=E$^α_K$ / (β+E$^α_K$) with α=0.70±0.08 and β=1.32±0.17 . In agreement with some previous works in other gas mixtures, we measured less ionization energy than predicted from SRIM simulations, the difference reaching 33% at 2 keV .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of proton light yield of water-based liquid scintillator

Abstract The proton light yield of liquid scintillators is an important property in the context of their use in large-scale neutrino experiments, with direct implications for neutrino-proton scattering measurements and the discrimination of fast neutrons from inverse $$\beta $$ β -decay coincidence signals. This work presents the first measurement of the proton light yield of a water-based liquid scintillator (WbLS) formulated from 5% linear alkyl benzene (LAB), at energies below 20 MeV, as well as a measurement of the proton light yield of a pure LAB + 2 g/L 2,5-diphenyloxazole (PPO) mixture (LABPPO). The measurements were performed using a double time-of-flight method and a pulsed neutron beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The proton light yields were measured relative to that of a 477 keV electron. The relative proton light yield of WbLS was approximately 3.8% lower than that of LABPPO, itself exhibiting a relative proton light yield 15–20% higher than previous measurements of an analogous anoxic sample. The observed quenching is not compatible with the Birks model for either material, but is well described with the addition of Chou’s bimolecular quenching term.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Phase separation, edge currents, and Hall effect for active matter with Magnus dynamics

Here we examine run-and-tumble disks in two-dimensional systems where the particles also have a Magnus component to their dynamics. For increased activity, we find that the system forms a motility-induced phase-separated (MIPS) state with chiral edge flow around the clusters, where the direction of the current is correlated with the sign of the Magnus term. The stability of the MIPS state is non-monotonic as a function of increasing Magnus term amplitude, with the MIPS region first extending down to lower activities followed by a break up of MIPS at large Magnus amplitudes into a gel-like state. We examine the dynamics in the presence of quenched disorder and a uniform drive and find that the bulk flow exhibits a drive-dependent Hall angle. This is a result of the side jump effect produced by scattering from the pinning sites and is similar to the behavior found for skyrmions in chiral magnets with quenched disorder.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

MIP-4 is Induced by Bleomycin and Stimulates Cell Migration Partially via Nir-1 Receptor

Background. CC-chemokine ligand 18 also known as MIP-4 is a chemokine with roles in inflammation and immune responses. It has been shown that MIP-4 is involved in the development of several diseases including lung fibrosis and cancer. How exactly MIP-4 is regulated and exerts its role in lung fibrosis remains unclear. Therefore, in the present study, we examined how MIP-4 is regulated and whether it acts via its potential receptor Nir-1. Materials and Methods. A549 cells were grown and maintained in DMEM : F12 (1 : 1) and supplemented with 10% FBS and 1000 U of penicillin/streptomycin and maintained as recommended by the manufacturer (ATCC). Cell migration and invasion, immunohistochemistry (IHC), Western blot, qPCR, and siRNA Nir-1 were used to determine MIP-4 regulation and its role in cell migration. Results. Cell migration was increased following stimulation of cells with recombinant (r) MIP-4 and bleomycin (BLM), whereas quenching rMIP-4 with its antibody (Ab) or addition of the Ab to BLM or H 2 O 2 diminished rMIP-4-induced cell migration. Along with cell migration, rMIP-4, BLM, and H 2 O 2 induced the formation of actin filaments dynamic structures whereas costimulation with MIP-4 Ab limited BLM- and H 2 O 2 -induced effects. MIP-4 mRNA and protein were increased by BLM and H 2 O 2 , and the addition of its Ab significantly reduced treatments effect. Experiments with siRNA investigating whether Nir-1 is a potential MIR-4 receptor indicated that the inhibition of Nir-1 decreased cell migration/invasion but did not totally inhibit rMIP-4-induced cell migration. Conclusion. Therefore, our data indicate that MIP-4 is regulated by BLM and H 2 O 2 and costimulation with its Ab limits the effects on MIP-4 and that the Nir-1 receptor partially mediates MIP-4’s effects on increased cell migration. These data also evidenced that MIP-4 is regulated by fibrotic and oxidative stimuli and that quenching MIP-4 with its Ab or therapeutically targeting the Nir-1 receptor may partially limit MIP-4 effects under fibrotic or oxidative stimulation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

How Snow Aggregate Ellipsoid Shape and Orientation Variability Affects Fall Speed and Self-Aggregation Rates

Snow aggregate shapes and orientations have long been known to exhibit substantial variability. Despite this observed variability, most weather and climate prediction models use fixed power-law functions that deterministically map particle size to mass and fall speed. As such, integrated quantities like precipitation and self-aggregation rates currently ignore nonlinear effects resulting from variation in shape and orientation for aggregates of the same size. This study therefore develops an analytic framework that couples an empirically based bivariate distribution of ellipsoid shapes to classical hydrodynamic theory so as to capture an appropriate dispersion of masses, projected areas, and fall speeds for an assumed size distribution. For a fixed aggregate size, shape variations produce approximately ±0.13 m s -1 standard deviation of fall speed which increases the mass flux fall speed dispersion by more than 100% over traditional microphysics models. This increased fall speed dispersion results predominantly from shape-induced mass dispersion whereas orientation and drag dispersion play a lesser role. Shape variations can increase mass- and reflectivity-weighted fall speeds by up to 60% of traditional models whereas self-aggregation rates can increase by a factor of 100 for very small slope parameters. This implies that aggregate shape variations effectively forestall the theorized onset of fall speed distribution narrowing and subsequent quenching of the aggregation process. As a result, it is likely that secondary ice formation is necessary to prevent an ever decreasing slope parameter. The mathematical theory presented in this study is used to develop simple correction factors for snow forecast and climate models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Data for Attributing Differences of Solar-Induced Chlorophyll Fluorescence (SIF)-Gross Primary Production (GPP) Relationships between Two C4 Crops, Corn and Miscanthus

Information to characterize the solar-induced chlorophyll fluorescence (SIF)-gross primary production (GPP) relationship in C4 cropping systems remains limited. The annual C4 crop corn and perennial C4 crop miscanthus differ in phenology, canopy structure and leaf physiology. Investigating the SIF-GPP relationships in these species could deepen our understanding of SIF-GPP relationships within C4 crops. Using in situ canopy SIF and GPP measurements for both species along with leaf-level measurements, we found considerable differences in the SIF-GPP relationships between corn and miscanthus, with a stronger SIF-GPP relationship and higher slope of SIF-GPP observed in corn compared to miscanthus. These differences were mainly caused by leaf physiology. For miscanthus, high non-photochemical quenching (NPQ) under high light, temperature and water vapor deficit (VPD) conditions caused a large decline of fluorescence yield (ΦF), which further led to a SIF midday depression and weakened the SIF-GPP relationship. The larger slope in corn than miscanthus was mainly due to its higher GPP in mid-summer, largely attributed to the higher leaf photosynthesis and less NPQ. Our results demonstrated variation of the SIF-GPP relationship within C4 crops and highlighted the importance of leaf physiology in determining canopy SIF behaviors and SIF-GPP relationships.

Feedstock Production↗
DOE OSTI2024

Comparing Pr 3+ and Nd 3+ for deactivating the Er 3+ : 4 I 13/2 level in lanthanum titanate glass

Erbium lanthanum titanate glasses were prepared by levitation melting for the spectroscopic study of ways to promote the mid-infrared fluorescence. Two series of heavily erbium doped glasses (15 wt%) were prepared with the addition of either Pr 3+ or Nd 3+ in amounts relative to Er 3+ of 0.05, 0.1, and 0.2. Both ions quench the lower Er 3+ laser level with the Pr 3+ doing so more rapidly. Although high co-dopant concentrations result in higher energy transfer, as clearly evidenced in upconversion and downconversion fluorescence measurements, the mid-infrared lifetime also suffers a reduction and, therefore, a balance must be struck in the co-dopant concentration. Lifetime and spectral measurements indicate that, at a fixed relative co-dopant amount, Pr 3+ is more effective than Nd 3+ at removing the bottleneck of the Er 3+ 4 I 13/2 level. Moreover, consideration of the lifetimes alongside the absorption data of the individual ions indicates that despite the large absorption cross-section of Nd 3+ at 808 nm, the concentration needed to yield more absorbed power than utilizing direct 976 nm excitation of Er 3+ results in unfavorable lifetimes of the mid-infrared transition. In the end, Pr 3+ prevails as the superior co-dopant in terms of the effects on fluorescence lifetimes as well as potential laser system design considerations. In a unique self-doping approach, a reducing melt atmosphere of Ar instead of O 2 creates a small fraction of Ti 3+ . In 5Er 2 O 3 -12La 2 O 3 -83TiO 2 glass, the presence of Ti 3+ quenches the 4 I 13/2 emission about 2.6 times more than the 4 I 11/2 when lifetimes are compared to an O 2 melt environment. As an additional means of increasing the mid-infrared emission, the effect of temperature on the mid- and near- infrared lifetimes of a lightly doped lanthanum titanate composition is investigated between 77-300 K. The mid-infrared lifetime increases by ∼30% while the near-infrared lifetime increases by ∼10%, which suggests in addition to co-doping, active cooling of the gain media will further enhance performance.

Materials Science↗
DOE OSTI2022

Scoping studies for low-temperature melting ZnO–Bi 2 O 3 –(B 2 O 3 , SiO 2 ) binder glass

In this work, low melting point glass systems were explored as candidates for binders of solid oxide nuclear wastes which include volatile elements such as radioactive iodine. The base glass systems considered were ZnO-Bi 2 O 3 -B 2 O 3 and ZnO-Bi 2 O 3 -SiO 2 , with specific compositions selected for synthesis trials based on available phase diagrams and a desire to explore the whole glass-forming region. Ten compositions were synthesized by melt quenching. Promising candidate glass binders were selected based on absence of crystallization and favorable thermal properties, including low glass transition temperature (T g ) combined with a high crystallization onset temperature. These thermal properties indicate stable glass forming which would lead to sintering behavior needed for glass binding. Compositional effects include: higher Bi 2 O 3 content lead to lower Tg values, high ZnO content generally led to crystallization on quench, and high SiO 2 content resulted in requirements for excessively high melting temperature. 25ZnO-15Bi 2 O 3 -60B 2 O 3 was down-selected for some detailed crystallization versus time and temperature studies.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2026

Performance enhancement of medium temperature baked niobium SRF cavity by surface contamination removal

Medium temperature baking (300- 350 °C) enhances the quality factor of niobium superconducting radio frequency cavities. However, surface contamination introduced during vacuum furnace baking limits the quench field and may also degrade the quality factor of the cavity. To investigate this effect, a 1.3 GHz single-cell Nb cavity underwent mid-T baking, followed by a chemical treatment to remove the surface contaminants. Post-treatment measurements revealed a significant improvement in both the quality factor and the quench field.

Chouhan, Vijay [Fermilab] (ORCID:0000000282004931)↗
DOE OSTI2023

MAGNETIC FIELD MAPPING OF A LARGE-GRAIN 1.3 GHz SINGLE-CELL CAVITY

A new magnetic field mapping system for 1.3 GHz single- cell cavities was developed in order to reveal the impact of ambient magnetic field and temperature gradients during cool-down on the flux trapping phenomenon. Measurements were done at 2 K for different cool-down conditions of a large-grain cavity before and after 120 °C bake. The fraction of applied magnetic field trapped in the cavity walls was ? 50% after slow cool-down and ? 20% after fast cool-down. The results showed a weak correlation between between trapped flux locations and hot-spots causing the high-field Q-slope. The results also showed an increase of the trapped flux at the quench location, after quenching, and a local redistribution of trapped flux with increasing RF field.

Ciovati, Gianluigi↗
DOE OSTI2023

Comparing the Effectiveness of Low Temperature Bake in EP and BCP Cavities

Electropolishing (EP) and buffered chemical polishing (BCP) are conventional surface preparation techniques for superconducting radiofrequency (SRF) cavities. Both EP and BCP treated SRF cavities display high field Q-slope (HFQS) which degrades performance at high gradients. While high gradient performance in EP cavities can be improved by introducing oxygen via a low temperature bake (LTB) of 120^{°}C by 48 hours, LTB does not consistently remove HFQS in BCP cavities. There is no consensus as to why LTB is not effective on BCP prepared cavities. We examine quench in EP, BCP, EP+LTB, and BCP+LTB treated 1.3 GHz single-cell Nb cavities by studying the heating behavior with field using a temperature mapping system. Cavity performance is correlated to characterizations of surface impurity profile obtained via time of flight secondary ion mass spectrometry studies. We observe a difference in near surface hydrogen concentration following BCP compared to EP that may suggest that the causes of quench in EP and BCP cavities are different.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Mechanically Polishing Electroplated Nb3Sn for Higher Accelerating Gradients

As the demand for more efficient SRF technology continues to rise, so does the need to improve the performance of Nb3Sn, the most promising alternative to niobium. Leveraging recent breakthroughs in Nb3Sn research from Cornell University and Fermilab, namely the electrochemical synthesis-based growth of Nb3Sn and the centrifugal barrel polishing (CBP) technique to smoothen the final Nb3Sn film, our primary goal is to reduce surface roughness while preserving the film’s quality. We present promising RF results from an electroplated cavity that underwent mechanical polishing using the CBP technique, which showed an increase in the maximum accelerating gradient compared to the baseline test. However, contamination-induced Q-slope limited performance. Temperature mapping reveals quench location and heating response before, during and after quench.

Shpani, L. [Cornell U.]↗
DOE OSTI2022

Asymptotics of transverse momentum broadening in dense QCD media

We study the asymptotic behaviour of the transverse momentum broadening distribution of an energetic quark or gluon propagating through dense QCD matter, in the large system size L L limit, taking into account radiative corrections in the double logarithmic approximation. Thanks to a connection between the evolution of the jet quenching parameter \hat{q} q ̂ and the formation of traveling wave fronts in nonlinear physics, we obtain a formula for the L L dependence of the characteristic transverse momentum scale Q_s Q s of the distribution valid up to terms of order 1/\ln(L) 1 / ln ( L ) . We briefly discuss the physical implications of this formula for jet quenching and small- x x phenomenology.

Caucal, Paul↗
DOE OSTI2020

Investigations on the Thermal-hydraulic Behavior of Accident Tolerant Fuel Cladding Materials

Since the 2011 Fukushima accident, significant research has been devoted to developing accident-tolerant fuel (ATF) cladding materials. These investigations have mostly focused on the ability to resist runaway steam oxidation and retain mechanical strength and structural integrity under thermal shocks. However, much remains unknown about the materials’ thermal-hydraulic behavior, particularly under light-water reactor (LWR) operating conditions. Two phenomena that determine safety margins in both normal and off-normal operating conditions - i.e., the critical heat flux (CHF) and Leidenfrost point (LFP) temperature - have not been investigated thoroughly for ATF materials. Surface properties, such as wettability and roughness, are known to influence pool and flow boiling CHF, as well as the LFP temperature. However, little is known about the surface wettability of ATF materials, particularly at LWR pressure and temperature. Little has been done on flow-boiling CHF and quenching heat transfer, especially for droplet quenching. Nonetheless, it is known that CHF in transient conditions, e.g., an exponentially escalating power transient, can be significantly different from that expected in steady-state operation. Very few studies have investigated transient CHF, either on ATF materials or under LWR pressure and temperature. The thorough understanding of transient CHF under prototypical reactor conditions will benefit not only the deployment of ATF but also the upcoming national efforts to study transient ATF behavior in the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory. In summary, as a part of ATF development efforts, there is an urgent need to understand how and how much these materials may affect two-phase heat transfer phenomena in nuclear reactor conditions.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2020

Study of Heavy Flavor Mesons and Flavor-Tagged Jets with the CMS Detector

The goal of this research program is to implement heavy flavor meson triggers in heavy-ion collisions for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) at CERN, including algorithm design, timing studies, offline validation, and online performance monitoring. The physics analyses which can be achieved by data from these new triggers is to address one of the most important questions in the field: parton flavor dependence of jet-quenching for the understanding of the transport properties of the Quark-Gluon Plasma. This program will allow CMS to collect the highest statistics heavy flavor meson and jet data ever recorded in heavy-ion colliders. The program includes two objectives: (1) Build and maintain the heavy flavor meson and jet triggers for heavy-ion collisions and deploy the trigger algorithms for 2015-2018 PbPb and pPb run at the LHC; (2) Perform heavy flavor meson and jet physics analyses, which can be used to study the parton flavor dependence of jet quenching, to extract the elastic energy loss coefficient of the QGP, and to test whether massive quarks also participate in collective expansion dynamics in heavy-ion collisions. With the heavy flavor physics trigger developed in this project, a competitive heavy flavor physics program in heavy-ion collisions has been established in CMS. This program allows studies of the fully reconstructed and flavor identified charm, beauty, and exotic hadrons that cover the widest transverse momentum range. The novel measurements supported by the award provide new constraints on the size of the flavor dependence of parton energy loss, the value of the in-medium charm quark diffusion coefficient, the mechanism of charm and beauty quark hadronization, and provide new insights to the nature of the X(3872) hadron.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Product consistency test results for the LAW Phase 4 gases

In this report, the Savannah River National Laboratory provides chemical analysis of Product Consistency Test (PCT) leachates from a series of simulated nuclear waste glasses fabricated at the Pacific Northwest National Laboratory (PNNL). The series included quenched and canister-centerline cooled (CCC) versions of the glasses. The resulting data will be used in the development of enhanced property/composition models for waste vitrification at Hanford. For some of the glass leachates, minor scatter among the triplicate values of some analytes were observed. For other leachates, there were more significant differences among the triplicate values. A review of the PCT data noted that there was little difference between the normalized values based on targeted or measured glass composition. Several of the study glasses have normalized concentration of element “i” (NCi) values that are greater than the Hanford Tank Waste Treatment and Immobilization Plant immobilized low-activity waste constraint of 4 g/L for boron (B), sodium (Na), and silicon (Si). The results of these glasses will help ensure the ability of advanced glass performance models to appropriately predict acceptable compositions. For the study glasses with NCi values exceeding 4 g/L, the CCC heat treatment samples had generally lower NCi values than quenched samples. The samples of the Environmental Assessment (EA) reference glass included with each PCT set had generally consistent NCi values. The release rates for boron (B), potassium (K), lithium (Li), sodium (Na), and silicon (Si) were highly correlated for the study glasses.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Characterization of the Sulfur-Saturated Melt Versions of the LAW Phase 4 Glasses

In this report, results are provided from the analyses of a series of sulfur-saturated melt versions of simulated nuclear waste glasses, and chemical analysis of the wash solution resulting from the preparation of these glasses. The glasses were selected and fabricated by the Pacific Northwest National Laboratory as part of a broader study of the influence of glass composition on chemical durability, sulfur retention, and other properties. The resulting data will be used in the development of enhanced property/composition models for waste vitrification at Hanford. Chemical analyses were performed on a representative sample of each of the sulfur-saturated versions of the quenched glasses to allow for comparisons with the targeted compositions, as well as the measured compositions of the quenched glasses. The measured concentrations of chlorine, and fluorine were below the targeted values for most of the study glasses, likely because of volatility during the multiple melting steps. The measured concentrations of B 2 O 3 , K 2 0, and Li 2 0 were generally low relative to the targeted values. As expected, the measured concentrations of SO 3 in most of the glasses were higher than targeted due to the use of the sulfur saturation method in fabricating these glasses. The wash solutions contained mainly sodium and sulfur, with moderate concentrations of potassium.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Composition Measurements of the HFG1 Glasses

This report provides results from the analyses of glass compositions for the High Fluoride Glasses-1, a series of simulated nuclear waste glasses fabricated at the Pacific Northwest National Laboratory. The series included the quenched version of the glasses. These data will be used to validate or identify areas of potential characterization improvements in the current glass property/composition models. Chemical analyses were performed on a representative sample of each of the quenched glasses to allow for comparisons with the targeted compositions. The relative differences between the targeted and measured concentrations of F, K 2 0, and Li 2 O for some of the glasses were greater than 10%. Overall, there were no indications of errors in batching of the simulated waste glasses. These results can be used in further characterization of this series of glasses, including the normalization of Product Consistency Test results.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗