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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Satellite Data Product and Data Dissemination Updates for the SPoRT Sea Surface Temperature Composite Product

The SPoRT SST composite is a reliable and robust high-resolution product generated twice per day in near real time. It incorporates highest quality data satellite data from infrared imagers and global analysis from NESDIS and UKMO. Recent updates to the product include the inclusion of VIIRS data to extend the life of the product beyond the MODIS era. It is used by a number of users in their DSS.

sea surface temperature↗
NASA NTRS2021

Rapid Cloud Removal of Dimethyl Sulfide Oxidation Products Limits SO 2 and Cloud Condensation Nuclei Production in the Marine Atmosphere

Oceans emit large quantities of dimethyl sulfide (DMS) to the marine atmosphere. The oxidation of 60 DMS leads to the formation and growth of cloud condensation nuclei (CCN) with consequent effects on Earth’s radiation balance and climate. Quantitative assessment of the impact of DMS emissions on CCN concentrations necessitates a detailed description of the oxidation of DMS in the presence of existing aerosol particles and clouds. In the unpolluted marine atmosphere, DMS is efficiently oxidized to hydroperoxymethyl thioformate (HPMTF), a stable intermediate in the chemical trajectory towards sulfur dioxide (SO 2 ) and ultimately sulfate aerosol (Veres et al. 2020). Using direct airborne flux measurements, we demonstrate that irreversible loss of HPMTF to clouds in the marine boundary layer determines the HPMTF lifetime (τ HPMTF < 2 hours) and terminates DMS oxidation to SO 2 in the cloudy marine boundary layer. When accounting for HPMTF cloud loss in a global chemical transport model, we show that SO 2 production from DMS is reduced by 35% globally and near surface (0-3km) SO 2 concentrations over the ocean are lowered by 24%. This large, previously unconsidered loss process for volatile sulfur accelerates the timescale for conversion of DMS to sulfate, while limiting new particle formation in the marine atmosphere and changing the dynamics of aerosol growth. This loss process potentially reduces the spatial scale over which DMS emissions contribute to aerosol production and growth and weakens the link between DMS emission and marine CCN production with subsequent implications for cloud formation, radiative forcing, and climate.

dimethyl sulfide↗
DOE OSTI2020

Production of liquids and reduced sulfur gaseous products from sour natural gas

Aspects of the invention are associated with the discovery of approaches for the conversion of sour natural gas streams, by conversion to liquid hydrocarbons. Particular processes and their associated apparatuses advantageously combine (i) dehydroaromatization (DHA) of methane in a gaseous feedstock, to produce aromatic hydrocarbons such as benzene, with (ii) the reaction of H2S and methane in this feedstock, to produce organic sulfur compounds such as carbon disulfide (CS2) and thiophene (C4H4S). A gaseous product having a reduced concentration of H2S is thereby generated. The aromatic hydrocarbons and organic sulfur compounds may be recovered in a liquid product. Both the gaseous and liquid products may be easily amenable to further upgrading. Other advantages of the disclosed processes and apparatuses reside in their simplicity, whereby the associated streams, including a potential gaseous recycle, generally avoid high partial pressures of H2S.

03 NATURAL GAS↗
DOE OSTI2024

Methods of sheet metal production and sheet metal products produced thereby

Processes for producing sheet metal products by machining a solid metal body with a cutting tool in a single step to continuously produce a continuous bulk form from material obtained from the solid metal body, and without performing a hot rolling operation thereon, cold rolling the continuous bulk form to produce a sheet metal product. The machining step is a large-strain machining process capable of being directly performed on an as-cast ingot or other solid body to produce a continuous intermediate product that can be directly cold rolled without any intervening hot rolling operation, and optionally without homogenization or annealing.

Trumble, Kevin Paul↗
DOE OSTI2017

Increasing Biomass Production on Limited Land Area Through an Optimal Planting Arrangement

Planting density is a primary consideration in silviculture; however, planting arrangement is often ignored. Most, if not all, forest plantations are arranged in rectangular or square lattices (i.e., grids). Using a simple mathematical model, we investigate the potential influence of planting arrangement on planting density, biomass yield, and rotation period by assuming that efficiently arranging trees is similar to packing congruent circles on a plane. The hexagonal lattice achieves the densest circle packing on a plane; therefore, a hexagonal or triangular lattice arrangement of stems provides the highest planting density for a given spacing. Using packing density to quantify arrangement efficiency, tree crowns in a hexagonal lattice fill approximately 90.7% of available area at initial canopy contact, while tree crowns in a square lattice fill approximately 78.5% of available area at initial canopy contact. The hexagonal lattice permits about a 15% higher density than the square lattice, which allows canopy closure to occur earlier without any change in individual tree growth. Short rotation woody crop (SRWC) systems are excellent candidates under the model's assumptions of level stand with even-age monoculture. If belowground resources are non-limiting, a hexagonal lattice arrangement shortens rotation period and thus optimizes the biomass yield per land area over time. Lastly, higher productivity over time is central to sustainable and efficient use of limited area for bioenergy and biomass products.

09 BIOMASS FUELS↗
DOE OSTI2022

Techno-economic analysis of offshore wind PEM water electrolysis for H 2 production

A model for producing hydrogen via offshore wind electrolysis was developed and the levelized costs of both energy and hydrogen were calculated. Here, this model calculated the cost of hydrogen produced by offshore wind and showed that the levelized cost of energy for hydrogen production and transportation to shore could be lower than for electricity transmission from offshore wind farms, using real wind data from a particular location. Therefore, direct coupling of the electrolysis system with offshore wind turbine is more advantageous than transmitting electricity to shore and then producing hydrogen via traditional electrolysis; the cost of hydrogen from offshore wind electrolysis is estimated to be $\$2.09$/kg, vs $\$3.86$/kg from traditional electrolysis using wind power.

08 HYDROGEN↗
DOE OSTI2011

[Ni(PPh2NBn2)2(CH3CN)]2+ as an Electrocatalyst for H2 Production: Dependence on Acid Strength and Isomer Distribution

[Ni(PPh2NBz2)2(CH3CN)](BF4)2, Ni(PPh2NBz2)22+ (where PPh2NBz2 is 1,5-dibenzyl-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane) has been studied as an electrocatalyst for the production of hydrogen in acetonitrile. Using strong acids, such as p cyanoanilinium, Ni(PPh2NBz2)22+ has been shown to be protonated under catalytic conditions prior to reduction, with an effective pKa of 6.7±0.4. Through multinuclear NMR spectroscopy studies, the nickel(II) complex was found to be doubly protonated without any observed singly protonated species. In the doubly protonated complex, both protons are positioned exo with respect to the metal center and are stabilized by an N-H-N hydrogen bond. The formation of exo protonated isomers is proposed to limit the rate of hydrogen production because the protons are unable to gain suitable proximity to the reduced metal center to generate dihydrogen. Pre-protonation of Ni(PPh2NBz2)22+ has been found to shift the catalytic operating potential to more positive potentials by up to 440 mV, depending upon the conditions. The catalytic rate was found to increase by an order of magnitude by increasing the solution pH or through the addition of water. This material is based upon work supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

08 HYDROGEN↗
DOE OSTI2014

Right-handed neutrino production rate at T>160 GeV

The production rate of right-handed neutrinos from a Standard Model plasma at a temperature above a hundred GeV has previously been evaluated up to NLO in Standard Model couplings (g∼2/3) in relativistic (M∼πT) and non-relativistic regimes (M≫πT), and up to LO in an ultrarelativistic regime (M≲gT). The last result necessitates an all-orders resummation of the loop expansion, accounting for multiple soft scatterings of the nearly light-like particles participating in 1↔2 reactions. In this paper we suggest how the regimes can be interpolated into a result applicable for any right-handed neutrino mass and at all temperatures above 160 GeV. The results can also be used for determining the lepton number washout rate in models containing right-handed neutrinos. Numerical results are given in a tabulated form permitting for their incorporation into leptogenesis codes. We note that due to effects from soft Higgs bosons there is a narrow intermediate regime around M∼g{sup 1/2}T in which our interpolation is phenomenological and a more precise study would be welcome.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Forward-backward asymmetry in top quark-antiquark production

We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a data set corresponding to an integrated luminosity of 5.4 fb{sup -1}, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 {+-} 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 {+-} 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 {+-} 4.0)%. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Diffractive dijet production in p̄p collisions at √s=1.96 TeV

We report on a study of diffractive dijet production in p̄p collisions at s√=1.96 TeV using the CDF II detector at the Fermilab Tevatron p̄p collider. A data sample from 310 pb⁻¹ of integrated luminosity collected by triggering on a high transverse energy jet, EjetT, in coincidence with a recoil antiproton detected in a Roman pot spectrometer is used to measure the ratio of single-diffractive to inclusive-dijet event rates as a function of x p̄ of the interacting parton in the antiproton, the Bjorken-x, x p̄ Bj , and a Q²≈(E jet T )² in the ranges 10⁻³ p̄ Bj <10⁻¹ and 10² p̄ <0.09 and a four-momentum transfer squared t p̄ >-4 GeV². The t p̄ dependence is measured as a function of Q² and x p̄ Bj and compared with that of inclusive single diffraction dissociation. We find weak x p̄ Bj and Q² dependencies in the ratio of single diffractive to inclusive event rates, and no significant Q² dependence in the diffractive t p̄ distributions.

Aaltonen, T.↗
DOE OSTI2011

Forward-Backward Asymmetry in tt Production from Flavor Symmetries

We show that the forward-backward asymmetry in top quark pair production can be enhanced by fields that transform nontrivially under the flavor group and satisfy minimal flavor violation, while at the same time the constraints from associated effects on the d{sigma}(tt)/dM{sub tt} distribution, dijet resonance searches, same-sign top-pair production, and other phenomenology are satisfied. We work out two examples in detail: one where a scalar color antisextet field that is also an antisextet of SU(3){sub U} enhances the forward-backward asymmetry and one where the enhancement arises from a vector color octet field that is also an octet of SU(3){sub U}.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Impact of Detailed Parameter Modeling of Open-Cycle Gas Turbines on Production Cost Simulation: Preprint

Flexible resources are increasingly important as variable renewable energy deployment in the power system increases. Although many systems are transitioning away from fossil fuels, open-cycle gas turbines are likely to play an important balancing role for some time, thus requiring accurate modeling of their operational parameters. This paper explores the impact of detailed representation of three operational parameters - start- up costs, run-up rates, and forced outage rates - in the production cost model of a system as it adopts higher levels of wind and solar. Using PLEXOS simulations of the NREL-118 bus test system, the study examines how more detailed parameter modeling affects outcomes such as the number of start-ups and shutdowns, ramping and total generation costs for open-cycle gas turbines, as renewable energy levels increase. The results suggest the value of detailed parameter modeling and continued research on combustion turbines' ability to provide flexibility.

economic dispatch↗