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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

System size and flavour dependence of chemical freeze-out temperatures in ALICE data from pp, pPb and PbPb collisions at LHC energies

We present the system size and flavour dependence of the chemical freeze-out temperature (T ch ) at vanishing baryo-chemical potential calculated via thermal fits to experimental yields for several multiplicity classes in pp, pPb and PbPb collisions measured by ALICE. Using the Thermal-FIST Hadron Resonance Gas model package, we compare the quality of fits across various treatments of strangeness conservation under different freeze-out conditions as a function of the charged particle multiplicity density $\langle$dN ch /d η $\rangle$. Additionally, we examine how the anti-hadron to pion yield ratios of light and strange baryons, as well as the φ meson, evolve within a flavour-dependent model. Through a unique twotemperature chemical freeze-out approach, we show that flavour dependence of T ch in a Strangeness Canonical Ensemble leads to a natural explanation of strangeness enhancement from small to large systems at LHC energies without requiring any non-equilibrium particle production at small $\langle$dN ch /d η $\rangle$.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Transcriptomic analysis of transgressive segregants revealed the central role of photosynthetic capacity and efficiency in biomass accumulation in sugarcane

Sugarcane is among the most efficient crops in converting solar energy into chemical energy. However, due to its complex genome structure and inheritance, the genetic and molecular basis of biomass yield in sugarcane is still largely unknown. We created an F2 segregating population by crossing S. officinarum and S. spontaneum and evaluated the biomass yield of the F2 individuals. The F2 individuals exhibited clear transgressive segregation in biomass yield. We sequenced transcriptomes of source and sink tissues from 12 selected extreme segregants to explore the molecular basis of high biomass yield for future breeding of high-yielding energy canes. Among the 103,664 assembled unigenes, 10,115 and 728 showed significant differential expression patterns between the two extreme segregating groups in the top visible dewlap leaf and the 9th culm internode, respectively. The most enriched functional categories were photosynthesis and fermentation in the high-biomass and the low-biomass groups, respectively. Our results revealed that high-biomass yield was mainly determined by assimilation of carbon in source tissues. The high-level expression of fermentative genes in the low-biomass group was likely induced by their low-energy status. Group-specific expression alleles which can be applied in the development of new high-yielding energy cane varieties via molecular breeding were identified.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Computational investigation of incident ion angles and material erosion at rough graphite and silicon carbide divertor surfaces

We present a computational investigation of the dependence of material erosion on the incident ion angle at rough graphite and silicon carbide divertor surfaces. Ion angle distributions (IADs) for D plasmas at NSTX-U and DIII-D divertors were calculated by an equation-of-motion model that traces the ion trajectories in the sheath. Then, the effective sputtering yields and ion shadowed area fractions were calculated by a Monte Carlo micro-patterning and roughness code that applied the calculated IADs to surface topographic data that were obtained from optical confocal microscopy of rough graphite and SiC divertor surfaces from NSTX-U and DIII-D experiments. The calculations found that the effective sputtering yields, the sputtering pattern, and the shadowed area are determined by the detailed surface topology rather than the root mean square roughness R RMS , which represents deviations from a flat surface. The suppression of the effective sputtering yields for rough surfaces compared to the yield for a smooth surface was accounted for by the change of the mean local incident ion angle (LIIA) (θ'). The mean surface inclination angle distribution (SIAD) (δ) was found to be a useful parameter to estimate the LIIA from the calculated IADs. We report global empirical formulas for the mean LIIA and fraction of the area shadowed from the main ions for D plasmas for rough surfaces with B-field incident angles α = 85°–89° as a function of the mean SIAD (δ). We propose the use of the mean LIIA (θ') to estimate the sputtering yield for rough surfaces from the angular dependence of the sputtering yield.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

ECCE unpolarized TMD measurements

For this work, we performed feasibility studies for various measurements that are related to unpolarized TMD distribution and fragmentation functions for the ECCE detector proposal. The processes studied include semi-inclusive Deep inelastic scattering (SIDIS) where single hadrons (pions and kaons) were detected in addition to the scattered DIS lepton. The single hadron cross sections and multiplicities were extracted as a function of the DIS variables x and Q 2 , as well as the semi-inclusive variables z, which corresponds to the momentum fraction the detected hadron carries relative to the struck parton and P T , which corresponds to the transverse momentum of the detected hadron relative to the virtual photon. The expected statistical precision of such measurements is extrapolated to accumulated luminosities of 10 fb –1 and potential systematic uncertainties are approximated given the deviations between true and reconstructed yields. The expected uncertainties are then used to obtain the expected impact on the related TMD distribution and fragmentation functions. We find that the ECCE detector proposal fulfills the physics requirements on these channels as detailed in the EIC Yellow Report.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Hydrotreating of Model Mixtures and Catalytic Fast Pyrolysis Oils over Pd/C

Noble metal catalysts may be attractive for hydrotreating of catalytic fast pyrolysis (CFP) oils. Model mixtures of raw noncatalytic fast pyrolysis and CFP oils representative of upgrading over HZSM-5 were hydrotreated in a batch reactor at 250-360 degrees C with palladium/carbon catalyst and 100 bar (cold) of hydrogen. The CFP oils gave high carbon yields of >95%, consumed less hydrogen per gram of oil produced, and had lower final oxygen concentrations than the raw oils did. GC/MS results were consistent with hydrogenation of alkenes and some oxygen-functionalized aromatic rings (e.g., phenolics) followed by hydrodeoxygenation at 360 degrees C. Complete deoxygenation was not obtained, and higher temperatures are recommended. The model oils' chemical transformations, carbon yields, and deoxygenation were similar to those of oils produced in a bench-scale reactor with HZSM-5 catalyst.

09 BIOMASS FUELS↗
DOE OSTI2023

Synthesis of Acid Hydrazides from Carboxylic Acids in Continuous Flow

A concise methodology for the synthesis of acid hydrazides from carboxylic acids via a continuous flow process in yields ranging from 65 to 91% is described. Using short residence times of between 13 and 25 mins, the conditions proved amenable to a variety of mono- and diacids, including aliphatic, aromatic, and heteroaromatic functionalities. Furthermore, to demonstrate scalability, a large-scale (200 g) synthesis of azelaic dihydrazide was conducted over a continuous run of 9 h with an 86% overall yield, equating to a 22 g/h output.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Characterization of Thin Film Materials using SCAN meta-GGA, an Accurate Nonempirical Density Functional

We discuss self-consistently obtained ground-state electronic properties of monolayers of graphene and a number of ’beyond graphene’ compounds, including films of transition-metal dichalcogenides (TMDs), using the recently proposed strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) to the density functional theory. The SCAN meta-GGA results are compared with those based on the local density approximation (LDA) as well as the generalized gradient approximation (GGA). As expected, the GGA yields expanded lattices and softened bonds in relation to the LDA, but the SCAN meta-GGA systematically improves the agreement with experiment. Our study suggests the efficacy of the SCAN functional for accurate modeling of electronic structures of layered materials in high-throughput calculations more generally.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Multiplicity-dependent production of Σ(1385) ± and Ξ(1530) 0 in pp collisions at $\sqrt{s}$ = 13 TeV

The production yields of the Σ(1385) ± and Ξ(1530) 0 resonances are measured in pp collisions at $\sqrt{s}$ = 13 TeV with ALICE. The measurements are performed as a function of the charged-particle multiplicity $\langle$dN ch /dη$\rangle$, which is related to the energy density produced in the collision. The results include transverse momentum (p T ) distributions, p T - integrated yields, mean transverse momenta of Σ(1385) ± and Ξ(1530) 0 , as well as ratios of the p T - integrated resonance yields relative to yields of other hadron species. The Σ(1385) ± /π ± and Ξ(1530) 0 /π ± yield ratios are consistent with the trend of the enhancement of strangeness production from low to high multiplicity pp collisions, which was previously observed for strange and multi-strange baryons. The yield ratio between the measured resonances and the long-lived baryons with the same strangeness content exhibits a hint of a mild increasing trend at low multiplicity, despite too large uncertainties to exclude the flat behaviour. The results are compared with predictions from models such as EPOS-LHC and PYTHIA 8 with Rope shoving. The latter provides the best description of the multiplicity dependence of the Σ(1385) ± and Ξ(1530) 0 production in pp collisions at $\sqrt{s}$ = 13 TeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Soybean ( Glycine max ) Haplotype Map (GmHapMap): a universal resource for soybean translational and functional genomics

Here, we describe a worldwide haplotype map for soybean (GmHapMap) constructed using whole-genome sequence data for 1007 Glycine max accessions and yielding 14.9 million variants as well as 4.3 M tag single-nucleotide polymorphisms (SNPs). When sampling random subsets of these accessions, the number of variants and tag SNPs plateaued beyond approximately 800 and 600 accessions, respectively. This suggests extensive coverage of diversity within the cultivated soybean. GmHapMap variants were imputed onto 21 618 previously genotyped accessions with up to 96% success for common alleles. A local association analysis was performed with the imputed data using markers located in a 1-Mb region known to contribute to seed oil content and enabled us to identify a candidate causal SNP residing in the NPC1 gene. We determined gene-centric haplotypes (407 867 GCHs) for the 55 589 genes and showed that such haplotypes can help to identify alleles that differ in the resulting phenotype. Finally, we predicted 18 031 putative loss-of-function (LOF) mutations in 10 662 genes and illustrated how such a resource can be used to explore gene function. The GmHapMap provides a unique worldwide resource for applied soybean genomics and breeding.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Charged-particle production as a function of multiplicity and transverse spherocity in pp collisions at $ \sqrt{s}$ = 5.02 and 13 TeV

Here, we present a study of the inclusive charged-particle transverse momentum ( p T ) spectra as a function of charged-particle multiplicity density at mid-pseudorapidity, d N ch /dη, in pp collisions at $ \sqrt{s}$ = 5.02 and 13 TeV covering the kinematic range |η| < 0.8 and 0.15 < p T < 20 GeV/ c . The results are presented for events with at least one charged particle in |η| < 1 (INEL>0). The p T spectra are reported for two multiplicity estimators covering different pseudorapidity regions. The p T spectra normalized to that for INEL>0 show little energy dependence. Moreover, the high- p T yields of charged particles increase faster than the charged-particle multiplicity density. The average p T as a function of multiplicity and transverse spherocity is reported for pp collisions at $ \sqrt{s}$=13 TeV. For low- (high-) spherocity events, corresponding to jet-like (isotropic) events, the average p T is higher (smaller) than that measured in INEL>0 pp collisions. Within uncertainties, the functional form of &lang; p T &rang; ( N ch ) is not affected by the spherocity selection. While EPOS LHC gives a good description of many features of data, PYTHIA overestimates the average p T in jet-like events.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Burst Pressure Solutions of Thin and Thick-Walled Cylindrical Vessels

Pressure vessels (PVs) are widely used in the energy industry. Accurate burst pressure is critical to structural design and safe operation for both thin and thick-walled PVs. The traditional strength theories utilized a single-parameter material property, such as the yield stress or the ultimate tensile stress (UTS) to develop failure models for determining the yield or ultimate pressure carrying capacity in the PV design. The UTS-based Barlow formula is a typical burst pressure model developed from the Tresca strength theory that provides the basis for developing regulation rules and failure models for different industry design codes, such as ASME BPVC, ASME B31.3, and ASME B31G, among others. In order to reduce the conservatism of the Tresca strength model, ASME BPVC recently adapted failure models developed from the von Mises strength theory for the PV design and analysis. It has been commonly accepted that the burst pressure of pipelines depends on the UTS and strain hardening exponent, n, of the pipeline steel. An average shear stress yield theory was thus developed, and the Zhu-Leis solution of burst pressure was obtained as a function of UTS and n for thin-walled line pipes. Experiments showed that the Zhu-Leis solution provides an accurate, reliable prediction of burst pressure for defect-free thin-walled pipes. In order to extend the Zhu–Leis solution to thick-walled cylindrical PVs, this paper defined three new flow stresses, modified the traditional strength theories, and obtained three new burst pressure solutions that are valid for both thin and thick-walled cylindrical vessels. The proposed flow stresses are able to describe the tensile strength and the plastic flow response of PVs for a strain hardening steel. The associated strength theories were then developed in terms of the Tresca, von Mises, and Zhu-Leis yield criteria. From these new strength theories, three burst pressure solutions were obtained for thick-walled cylinders, where the von Mises solution is an upper bound prediction, the Tresca solution is a lower bound prediction, and the Zhu-Leis solution is an intermediate prediction of burst pressure for thick-walled cylinders. Lastly, the proposed burst pressure solutions were evaluated and validated by two large datasets of full-scale burst tests for thick-walled tubes and for thin-walled pipes.

42 ENGINEERING↗
DOE OSTI2022

All-optical nanoscopic spatial control of molecular reaction yields on nanoparticles

Molecular adsorbate reactions on nanoparticles play a fundamental role in areas such as nano-photocatalysis, atmospheric, and astrochemistry. They can be induced, enhanced, and controlled by field localization and enhancement on the nanoparticle surface. In particular, the ability to perform highly controlled near-field-mediated reactions is key to deepening our understanding of surface photoactivity on nanosystems. Here, using reaction nanoscopy, we experimentally demonstrate all-optical nanoscopic control of surface reaction yields by tailoring the near fields on nanoparticles with waveform-controlled linear and bicircular two-color laser pulses, respectively. We observe site-selective proton emission from the dissociative ionization of adsorbate molecules on Si O 2 nanoparticles as a function of the polarization and relative phase of the two-color pulses. The angularly resolved close-to-uniform mapping between the surface reaction yields and the measured ion momentum enables the observation and spatial control of molecular reactions on the nanoparticle surface with nanoscopic resolution. The experimental results are modeled and reproduced qualitatively by classical trajectory Monte Carlo simulations. Our work paves the way toward reliable all-optical control of photocatalytic chemical reactions on nanoscale surfaces.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Predictions of Yield Strength Evolution Due to Physical Aging of 828 DGEBA/DEA using the Simplified Potential Energy Clock Model

The capability of the Simplified Potential Energy Clock Model (SPEC) to represent the uniaxial compression yield strength evolution under isothermal aging conditions is evaluated for a widely used epoxy thermoset encapsulation material, 828 DGEBA/DEA. A baseline model calibration is used. We note that this calibration did not consider yield strength behavior close to the glass transition temperature ( T g ), but in this work, the model is exercised in this temperature range to evaluate the ability to predict changes in material response with aging as equilibrium is approached. Some model alterations were needed to remove negative Prony weights in the thermal and bulk relaxation function ( f 1 ), which is chiefly responsible for aging in this analysis, but otherwise, the model was not altered. Model predictions of yield stress evolution are quantitatively different compared with experiments, but the rate of change of yield stress with respect to aging time is in reasonable agreement with respect to experiments for the first 1000 hours of aging. After this aging time, the measured yield stress stops evolving, but the model continues to evolve for several more decades in time. Parametric studies and model alterations are considered to investigate how yield strength evolution predictions are affected by modeling choices. It is clear that the baseline calibration must be re-examined in order to represent the aging data quantitatively.

42 ENGINEERING↗
DOE OSTI2016

Structural and Functional Influence of the Glycine-Rich Loop G 302 GGGY on the Catalytic Tyrosine of Histone Deacetylase 8

Histone deacetylase 8 (HDAC8) catalyzes the hydrolysis of acetyl-l-lysine to yield products l-lysine and acetate through a mechanism in which a nucleophilic water molecule is activated by a histidine general base and a catalytic metal ion (Zn 2+ or Fe 2+ ). Acetyl-l-lysine also requires activation by metal coordination and a hydrogen bond with catalytic tyrosine Y306, which also functions in transition state stabilization. Interestingly, Y306 is located in the conserved glycine-rich loop G 302 GGGY. The potential flexibility afforded by the tetraglycine segment may facilitate induced-fit conformational changes in Y306 between “in” and “out” positions, as observed in related deacetylases. To probe the catalytic importance of the glycine-rich loop in HDAC8, we rigidified this loop by preparing the G302A, G303A, G304A, and G305A mutants and measured their steady state kinetics and determined their X-ray crystal structures. Substantial losses of catalytic efficiency are observed (10–500-fold based on kcat/KM), particularly for G304A HDAC8 and G305A HDAC8. These mutants also exhibit the greatest structural changes for catalytic tyrosine Y306 (1.3–1.7 Å shifts of the phenolic hydroxyl group). Molecular dynamics simulations further indicate that G304 and G305 undergo pronounced structural changes as residue 306 undergoes a transition between “in” and “out” conformations. Thus, the G304A and G305A substitutions likely compromise the position and conformational changes of Y306 required for substrate activation and transition state stabilization. Here, the G302A and G303A substitutions have less severe catalytic consequences, and these substitutions may influence an internal channel through which product acetate is believed to exit.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Synthesis of End-Functionalized Poly(norbornenes) and Poly(ethylidene norbornenes) Using a Pd(II) Catalyst in Combination with Chain Transfer Agents

Synthesis of end-functionalized poly(norbornene)s (PNBs) and poly(ethylidenenorbornene)s (PENBs) were prepared using the palladium catalyst t Bu 3 PPdMeCl/NaBAr f in combination with chain transfer agents (CTAs) 4-penten-1-ol and 10-undecenal. These CTAs produce polymers end-capped with -OH and -CHO groups, respectively, in high yields with M n values in the range of 6K to 17K, depending on the molar ratio of the CTA: monomer. End-functionalized PNBs and PENBs with precisely controlled Mn values and very narrow molecular weight distributions were accessed by using 4-penten-1-ol and 10-undecenal as chain-terminating agents following living polymerizations in which monomer is completely consumed. The utility of the aldehyde-functionalized polymers is illustrated via coupling to a dye molecule and by synthesis of ambiphilic diblock copolymers, PNB-b-PEG and PENB-b-PEG.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

High marker density GWAS provides novel insights into the genomic architecture of terpene oil yield in Eucalyptus

Terpenoid-based essential oils are economically important commodities, yet beyond their biosynthetic pathways, little is known about the genetic architecture of terpene oil yield from plants. Transport, storage, evaporative loss, transcriptional regulation and precursor competition may be important contributors to this complex trait. Here, we associate 2.39 million single nucleotide polymorphisms derived from shallow whole-genome sequencing of 468 Eucalyptus polybractea individuals with 12 traits related to the overall terpene yield, eight direct measures of terpene concentration and four biomass-related traits. Our results show that in addition to terpene biosynthesis, development of secretory cavities, where terpenes are both synthesized and stored, and transport of terpenes were important components of terpene yield. For sesquiterpene concentrations, the availability of precursors in the cytosol was important. Candidate terpene synthase genes for the production of 1,8-cineole and α-pinene, and β-pinene (which comprised > 80% of the total terpenes) were functionally characterized as a 1,8-cineole synthase and a β/α-pinene synthase. Our results provide novel insights into the genomic architecture of terpene yield and we provide candidate genes for breeding or engineering of crops for biofuels or the production of industrially valuable terpenes.

1,8‐cineole↗
DOE OSTI2017

Tutorial: Reactive high power impulse magnetron sputtering (R-HiPIMS)

High Power Impulse Magnetron Sputtering (HiPIMS) is a coating technology that combines magnetron sputtering with pulsed power concepts. Furthermore, by applying power in pulses of high amplitude and a relatively low duty cycle, large fractions of sputtered atoms and near-target gases are ionized. In contrast to conventional magnetron sputtering, HiPIMS is characterized by self-sputtering or repeated gas recycling for high and low sputter yield materials, respectively, and both for most intermediate materials. The dense plasma in front of the target has the dual function of sustaining the discharge and providing plasma-assistance to film growth, affecting the microstructure of growing films. Many technologically interesting thin films are compound films, which are composed of one or more metals and a reactive gas, most often oxygen or nitrogen. When reactive gas is added, non-trivial consequences arise for the system because the target may become “poisoned,” i.e., a compound layer forms on the target surface affecting the sputtering yield and the yield of secondary electron emission and thereby all other parameters. It is emphasized that the target state depends not only on the reactive gas' partial pressure (balanced via gas flow and pumping) but also on the ion flux to the target, which can be controlled by pulse parameters. This is a critical technological opportunity for reactive HiPIMS (R-HiPIMS). The scope of this tutorial is focused on plasma processes and mechanisms of operation and only briefly touches upon film properties. It introduces R-HiPIMS in a systematic, step-by-step approach by covering sputtering, magnetron sputtering, reactive magnetron sputtering, pulsed reactive magnetron sputtering, HiPIMS, and finally R-HiPIMS. The tutorial is concluded by considering variations of R-HiPIMS known as modulated pulsed power magnetron sputtering and deep-oscillation magnetron sputtering and combinations of R-HiPIMS with superimposed dc magnetron sputtering.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗