Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Indices”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Does the vacuum gravitate on microscopic scales? Rydberg atoms indicate probably not

The cosmological constant presents one of the most fascinating and confounding problems in physics. A straightforward, seemingly robust prediction of quantum mechanics and general relativity is that the vacuum energy gravitates. Therefore, the cosmological constant should be enormous. It is minuscule. Since there is no understanding of why the cosmological constant is so small, it is important to test this idea in many different situations. In particular, given the span of distances in astronomy and particle physics, it is vital to test the gravitation of vacuum energy on as many distance scales as we can. Rydberg atoms open up a new set of distances for exploration. It is satisfying to measure the cosmological constant with an atom, but its main significance is extending measurements to microscopic distances. Here, too, there is no evidence of the gravitation of the vacuum. At scales of a micron and less, we place a limit of 7 GeV on the scale of gravitating vacuum energy, well below the scale of 100 GeV of the Standard Model of particle physics.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Indications for Freeze-Out of Charge Fluctuations in the Quark-Gluon Plasma at the LHC

The D-measure of net-charge fluctuations quantifies the variance of net charge in strongly interacting matter. It was introduced over 20 years ago as a potential signal of quark-gluon plasma (QGP) in heavy-ion collisions, where it is expected to be suppressed due to the fractional electric charges of quarks. Measurements have been performed at RHIC and LHC, but the conclusion has been elusive in the absence of quantitative calculations for both scenarios. We address this issue by employing a recently developed formalism of density correlations and incorporate resonance decays, local charge conservation, and experimental kinematic cuts. We find that the hadron gas scenario is in fair agreement with the ALICE data for $\sqrt{{𝑠}_{\textrm{NN}}}$ = 2.76 TeV Pb–Pb collisions only when a very short rapidity range of local charge conservation is enforced, while the QGP scenario is in excellent agreement with experimental data and largely insensitive to the range of local charge conservation. A Bayesian analysis of the data utilizing different priors yields moderate evidence for the freeze-out of charge fluctuations in the QGP phase relative to hadron gas. The upcoming high-fidelity measurements from LHC Run 2 will serve as a precision test of the two scenarios.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

The loss or absence of minimal residual disease of <0·1% at any time after two cycles of consolidation chemotherapy in CBFB–MYH11 ‐positive acute myeloid leukaemia indicates poor prognosis

Summary No consensus has been reached on the relationship between CBFB‐MYH11 copies and prognosis. Of 1525 acute myeloid leukemia (AML) patients, 58 with CBFB‐MYH11‐positive AML (16/58 patients with c‐kit mutation) were retrospectively analyzed with a median follow‐up duration of 29.8 (range: 4.8–74.4) months. Of these, 25/58 (43.1%) patients underwent allogeneic hematopoietic stem cell transplantation (allo‐HSCT), 10 of whom had the c‐kit mutation. Of the 33 patients who did not undergo allo‐HSCT, recurrence in patients with CBFB‐MYH11/ABL level >0.1% at any time after two consolidation cycles was significantly higher than in patients with CBFB‐MYH11/ABL level <0.1% (61.9% vs. 0%, P = 0.001); further, the 3‐year relapse‐free survival (RFS; 31.4% vs. 100%, P = 0.004) and event‐free survival (EFS; 33.1% vs. 100%, P = 0.004) were significantly decreased in patients with CBFB‐MYH11/ABL level >0.1% at any time after two consolidation cycles. The 3‐year RFS and EFS rates were lower in patients who did not receive allo‐HSCT than in those who did (31.4% vs 84.6%, P = 0.000; 31.4% vs. 80.8%, P = 0.001). CBFB‐MYH11‐positive AML patients with CBFB‐MYH11/ABL level >0.1% at any time after two cycles of consolidation had poor prognoses, and allo‐HSCT could improve their survival.

Duan, Wenbing↗
DOE OSTI2023

Field‐scale analysis of miscanthus production indicates climate change may increase the opportunity for water quality improvement in a key Iowa watershed

Abstract The Raccoon River Basin is the primary source for drinking water in Iowa's largest city and plays a major role in the Mississippi River Basin's high nutrient exports. Future climate change may have major impacts on the biological, physiological, and agronomic processes imposing a threat to ecosystem services. Efforts to reduce nitrogen (N) loads within this basin have included local litigation and the implementation of the Iowa Nutrient Reduction Strategy, which suggest incorporating bioenergy crops (i.e., miscanthus) within the current corn–soybean landscape to reach a 41% reduction in nitrate loads. This study focuses on simulating N export for historical and future land use scenarios by using an agroecosystem model (Agro‐IBIS) and a hydrology model (THMB) at the 500‐m resolution, similar to the scale of agricultural fields. Model simulations are driven by CMIP5 climate data for historical, mid‐century, and late‐century under the RCP 4.5 and 8.5 warming projections. Using recent crop profit analyses for the state of Iowa, profitability maps were generated and nitrogen leaching thresholds were used to determine where miscanthus should replace corn–soybean area to maximize reductions in N pollution. Our results show that miscanthus inclusion on low profit and high N leaching areas can result in a 4% reduction of N loss under current climate conditions and may reduce N loss by 21%–26% under future climate conditions, implying that water quality has the potential continue to improve under future climate conditions when strategically implemented conservation practices are included in future farm management plans.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Genetically-determined variations in photosynthesis indicate roles for specific fatty acid species in chilling responses

Using a population of recombinant inbred lines (RILs) cowpea (Vigna unguiculata. L. Walp), we tested for co-linkages between lipid contents and chilling responses of photosynthesis. Under low-temperature conditions (19°C/13°C, day/night), we observed co-linkages between quantitative trait loci intervals for photosynthetic light reactions and specific fatty acids, most strikingly, the thylakoid-specific fatty acid 16:1 Δ3trans found exclusively in phosphatidylglycerol (PG 16:1t). By contrast, we did not observe co-associations with bulk polyunsaturated fatty acids or high-melting-point-PG (sum of PG 16:0, PG 18:0 and PG 16:1t) previously thought to be involved in chilling sensitivity. These results suggest that in cowpea, chilling sensitivity is modulated by specific lipid interactions rather than bulk properties. We were able to recapitulate the predicted impact of PG 16:1t levels on photosynthetic responses at low temperature using mutants and transgenic Arabidopsis lines. Because PG 16:1t synthesis requires the activity of peroxiredoxin-Q, which is activated by H 2 O 2 and known to be involved in redox signalling, here we hypothesise that the accumulation of PG 16:1t occurs as a result of upstream effects on photosynthesis that alter redox status and production of reactive oxygen species.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Antigenic Distance between North American Swine and Human Seasonal H3N2 Influenza A Viruses as an Indication of Zoonotic Risk to Humans

Human-to-swine transmission of influenza A virus (IAV) repeatedly occurs, leading to sustained transmission and increased diversity in swine; human seasonal H3N2 introductions occurred in the 1990s and 2010s and were maintained in North American swine. Swine H3N2 strains were subsequently associated with zoonotic infections, highlighting the need to understand the risk of endemic swine IAV to humans. We quantified antigenic distances between swine H3N2 and human seasonal vaccine strains from 1973 to 2014 using a panel of monovalent antisera raised in pigs in hemagglutination inhibition (HI) assays. Swine H3N2 lineages retained the closest antigenic similarity to human vaccine strains from the decade of incursion. Swine lineages from the 1990s were antigenically more similar to human vaccine strains of the mid-1990s but had substantial distance from recent human vaccine strains. In contrast, lineages from the 2010s were closer to human vaccine strains from 2011 and 2014 and the most antigenically distant from human vaccine strains prior to 2007. HI assays using ferret antisera demonstrated that swine lineages from the 1990s and 2010s had significant fold reductions compared to the homologous HI titer of the nearest pandemic preparedness candidate vaccine virus (CVV) or seasonal vaccine strain. The assessment of postinfection and postvaccination human serum cohorts demonstrated limited cross-reactivity to swine H3N2 from the 1990s, especially in older adults born before the 1970s. We identified swine strains to which humans are likely to lack population immunity or are not protected against by a current human seasonal vaccine or CVV to use in prioritizing future human CVV strain selection.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Shotgun metagenomics analysis indicates Bradyrhizobium spp. as the predominant genera for heavy metal resistance and bioremediation in a long-term heavy metal-contaminated ecosystem

ABSTRACT Ten soil cores were collected from the long-term heavy metal-contaminated Savannah River Site (SRS) and studied using shotgun metagenomics. In-line with our previous reports, Bradyrhizobium spp. dominated the SRS soils, and thus we recommend that SRS bioremediation studies target the Bradyrhizobium genus.

Agashe, Rohan↗
DOE OSTI2026

Housing Unit Level Social Vulnerability Indices for 2010 and 2020

Housing unit level demographic characteristics for SETX counties. Census years 2010 and 2020. These data are in beta testing stage, designed for use with the SETX-UIFL project. Contact Nathanael Rosenheim (nrosenheim@arch.tamu.edu) for more information. Papers using these data should include Nathanael Rosenheim in the development phase and co-authorship discussions.

Rosenheim, Nathanael↗
DOE OSTI2022

Indications of a Decrease in the Depth of Deep Convective Cores with Increasing Aerosol Concentration during the CACTI Campaign

Abstract An aerosol indirect effect on deep convective cores (DCCs), by which increasing aerosol concentration increases cloud-top height via enhanced latent heating and updraft velocity, has been proposed in many studies. However, the magnitude of this effect remains uncertain due to aerosol measurement limitations, modulation of the effect by meteorological conditions, and difficulties untangling meteorological and aerosol effects on DCCs. The Cloud, Aerosol, and Complex Terrain Interactions (CACTI) campaign in 2018–19 produced concentrated aerosol and cloud observations in a location with frequent DCCs, providing an opportunity to examine the proposed aerosol indirect effect on DCC depth in a rigorous and robust manner. For periods throughout the campaign with well-mixed boundary layers, we analyze relationships that exist between aerosol variables (condensation nuclei concentration > 10 nm, 0.4% cloud condensation nuclei concentration, 55–1000-nm aerosol concentration, and aerosol optical depth) and meteorological variables [level of neutral buoyancy (LNB), convective available potential energy, midlevel relative humidity, and deep-layer vertical wind shear] with the maximum radar-echo-top height and cloud-top temperature (CTT) of DCCs. Meteorological variables such as LNB and deep-layer shear are strongly correlated with DCC depth. LNB is also highly correlated with three of the aerosol variables. After accounting for meteorological correlations, increasing values of the aerosol variables [with the exception of one formulation of aerosol optical depth (AOD)] are generally correlated at a statistically significant level with a warmer CTT of DCCs. Therefore, for the study region and period considered, increasing aerosol concentration is mostly associated with a decrease in DCC depth.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Structural homology of mite profilins to plant profilins is not indicative of allergic cross-reactivity

Abstract Structural and allergenic characterization of mite profilins has not been previously pursued to a similar extent as plant profilins. Here, we describe structures of profilins originating fromTyrophagus putrescentiae(registered allergen Tyr p 36.0101) andDermatophagoides pteronyssinus(here termed Der p profilin), which are the first structures of profilins from Arachnida. Additionally, the thermal stabilities of mite and plant profilins are compared, suggesting that the high number of cysteine residues in mite profilins may play a role in their increased stability. We also examine the cross-reactivity of plant and mite profilins as well as investigate the relevance of these profilins in mite inhalant allergy. Despite their high structural similarity to other profilins, mite profilins have low sequence identity with plant and human profilins. Subsequently, these mite profilins most likely do not display cross-reactivity with plant profilins. At the same time the profilins have highly conserved poly(l-proline) and actin binding sites.

Biochemistry & Molecular Biology↗
DOE OSTI2023

Supporting data for "Frozen flume experiments indicate rapid permafrost riverbank erosion depends on bank roughness"

This dataset contains supporting files detailing five frozen flume experiments conducted at the Caltech Earth Surface Dynamics Laboratory to investigate rates of ablation-limited permafrost riverbank erosion under controlled conditions. Water flowed past a bank of saturated, frozen sand and ice and gradually eroded the bank by thawing pore ice and immediately entraining sand and washing it downstream. Experiments were scaled for flow hydraulics and heat transfer allowing comparisons between our results and natural permafrost riverbanks. For each experiment, we measured the initial and final sand bank topography using a Keyence laser scanner, water surface slope at 3-min intervals throughout the experiment using a Massa sonar scanner, bank erosion using 10-sec overhead timelapse imagery taken by an overhead camera, water and bank temperature using thermistors frozen into the sand bank and sampling at 2 Hz, and water discharge using an in-line flow meter. We include calibration data for the carriage (engineered by the Saint Anthony Falls Laboratory) used to make sonar and laser topography measurements. We also include calibration data for temperature sensors, water discharge measurements, and images of a regular grid placed in the flume to align overhead camera images with the carriage datum. Grain size analysis for the channel bed (gravel) was produced using a pebble count and bank sand was measured using a Camsizer X2. In addition to the five frozen experiments, we include sonar scans of water surface slope and Keyence scans of bed and bank topography for calibration experiments ran with an immobile gravel bank and bed.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Basic Research of Intrinsic Tamper indication Markings and Patterns defined by Pulsed Laser Irradiation

With our previous research, it was found that surface asperities or roughness must be present to create periodic surface structures upon laser exposure. In particular, an initial rough surface morphology (such as that found with a machined surface) provides multiple sites for light scattering, which underlies the formation of periodic ripple morphologies. Light scattering from a random surface creates patterns of periodic structures (with complex orientations) that could be used as intrinsic markings for tagging materials and equipment. Despite these initial findings, the fundamental mechanisms that give rise to periodic surface structures and their characteristic shapes were not identified in prior research.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Image quality indicator and dechromator setup for static LANSCE proton radiography experiment

This document describes a static geometry consisting of a sphere of gold and Ti-6Al-4V alloy, along with an energy-loss matching dechromator composed of polycarbonate, to field with the X3 electromagnetic magnifying lens at LANSCE during the next beam cycle. This static configuration will allow us to: (1) characterize the system’s resolution at the material interface between the gold and titanium alloy, and test the image quality for fine features associated with the screws used to fasten the titanium alloy hemispheres; (2) tune our models of proton scattering and imaging for these materials; and (3) test a procedure to align the polycarbonate dechromator and the sphere within the proton beamline. The data will also be suitable for validation of the software options available for proton radiography simulations.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗