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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Renormalizability of the linearly broken formulation of the BRST symmetry in the presence of the Gribov horizon in Landau gauge Euclidean Yang-Mills theories

In previous work by M. A. L. Capri, A. J. Gomez, M. S. Guimaraes, V. E. R. Lemes, S. P. Sorella, and D. G. Tedesco [Phys. Rev. D 82, 105019 (2010)], we have shown that the soft breaking of the Becchi-Rouet-Stora-Tyutin (BRST) symmetry arising within the Gribov-Zwanziger framework can be converted into a linear breaking, while preserving the nilpotency of the BRST operator. Because of its compatibility with the quantum action principle, the linearly broken BRST symmetry directly translates into a set of Slavnov-Taylor identities. We show that these identities guarantee the multiplicative renormalizability of both Gribov-Zwanziger and refined Gribov-Zwanziger theories to all orders. The known property that only two renormalization factors are needed is recovered. The nonrenormalization theorem of the gluon-ghost-antighost vertex, as well as the renormalization factor of the Gribov parameter, are derived within the linearly broken formulation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Percolation Transition in Yang-Mills Matter at a Finite Number of Colors

We examine baryonic matter at a quark chemical potential of the order of the confinement scale {mu}{sub q{approx}{Lambda}QCD}. In this regime, quarks are supposed to be confined but baryons are close to the 'tightly packed limit' where they nearly overlap in configuration space. We show that this system will exhibit a percolation phase transition when varied in the number of colors N{sub c}: at high N{sub c}, large distance correlations at the quark level are possible even if the quarks are essentially confined. At low N{sub c}, this does not happen. We discuss the relevance of this for dense nuclear matter, and argue that our results suggest a new 'phase transition', varying N{sub c} at constant {mu}{sub q}.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

On mass-shell renormalizability of the massive Yang-Mills theory

Renormalizable theory of electroweak interactions without scalar particles can be constructed by the modifying the Standard Model. One should remove all terms with the scalar field from the Lagrangian in the unitary gauge. The resulting electroweak theory without the Higgs particle is on mass-shell renormalizable and unitary. Thus the experimental non-observation of the Higgs boson will not mean a problem for the concept of renormalizability in quantum field theory but will confirm the scalar free theory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Trochoidal slot milling

Parameter specification in the trochoidal machining of a slot of constant width is considered. A formula is proposed for the displacement increment of the shaping circle as a function of the cutting depth.

42 ENGINEERING↗
DOE OSTI2018

The Usage of Error Compensation Tools of CNC for Vertical Milling Machines

The error of metal-cutting machines must be kept within standard limits when a numerical control system is first introduced. A mechanism for more precise control of the motion is proposed on the basis of control modules in the core of the CNC. The results of using the proposed approach when the AxiOMA Control numerical control system is introduced at the Quaser MV184 machine tool (produced by “KEMZ” Ltd.) are outlined.

42 ENGINEERING↗
DOE OSTI2010

AFFECTS OF MECHANICAL MILLING AND METAL OXIDE ADDITIVES ON SORPTION KINETICS OF 1:1 LiNH2/MgH2 MIXTURE

The destabilized complex hydride system composed of LiNH{sub 2}:MgH{sub 2} (1:1 molar ratio) is one of the leading candidates of hydrogen storage with a reversible hydrogen storage capacity of 8.1 wt%. A low sorption enthalpy of {approx}32 kJ/mole H{sub 2} was first predicted by Alapati et al. utilizing first principle density function theory (DFT) calculations and has been subsequently confirmed empirically by Lu et al. through differential thermal analysis (DTA). This enthalpy suggests that favorable sorption kinetics should be obtainable at temperatures in the range of 160 C to 200 C. Preliminary experiments reported in the literature indicate that sorption kinetics are substantially lower than expected in this temperature range despite favorable thermodynamics. Systematic isothermal and isobaric sorption experiments were performed using a Sievert's apparatus to form a baseline data set by which to compare kinetic results over the pressure and temperature range anticipated for use of this material as a hydrogen storage media. Various material preparation methods and compositional modifications were performed in attempts to increase the kinetics while lowering the sorption temperatures. This paper outlines the results of these systematic tests and describes a number of beneficial additions which influence kinetics as well as NH{sub 3} formation.

08 HYDROGEN↗
DOE OSTI2016

2D Kac-Moody symmetry of 4D Yang-Mills theory

Scattering amplitudes of any four-dimensional theory with nonabelian gauge group G may be recast as two-dimensional correlation functions on the asymptotic twosphere at null in nity. The soft gluon theorem is shown, for massless theories at the semiclassical level, to be the Ward identity of a holomorphic two-dimensional G-Kac-Moody symmetry acting on these correlation functions. Holomorphic Kac-Moody current insertions are positive helicity soft gluon insertions. Furthermore, the Kac-Moody transformations are a CPT invariant subgroup of gauge transformations which act nontrivially at null in nity and comprise the four-dimensional asymptotic symmetry group.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Yangian invariants and cluster adjacency in $ \mathcal{N} $ = 4 Yang-Mills

We conjecture that every rational Yangian invariant in $ \mathcal{N} $ = 4 SYM theory satisfies a recently introduced notion of cluster adjacency. We provide evidence for this conjecture by using the Sklyanin Poisson bracket on Gr(4, n) to check numerous examples.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Fueling Peter’s Mill: Mikhail Lomonosov’s Educational Training in Russia and Germany, 1731–1741

This article, the second in a series about the Russian scientist Mikhail Lomonosov (1711–1765), traces his education from his arrival in Moscow in 1731 to study at the Slavo- Greco-Latin Academy, through his admission to the St. Petersburg Academy of Sciences in 1736, to his trip abroad to complete his educational studies from 1736 to 1741. Lomonosov’s story during this time opens a vista on the introduction of modern physics and modern science into Russia. Michael D. Gordin has argued that Peter the Great’s plans to Westernize Russia were more broadly conceived than he is usually credited, with ambitions that exceeded mere utilitarian and pragmatic goals. Lomonosov’s career trajectory is a good example, illustrating how different aspects of the Petrine vision intersected with and reinforced each other. Here, the article ends with Lomonosov’s return to Russia from Germany in 1741, an important landmark in the growth of the Academy and of Russian science.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2012

Ethanol Addition for Enhancing Denitrification at the Uranium Mill Tailing Site in Monument Valley, AZ

Uranium mining and processing near Monument Valley, Arizona resulted in the formation of a large nitrate plume in a shallow alluvial aquifer. The results of prior field characterization studies indicate that the nitrate plume is undergoing a slow rate of attenuation via denitrification, and the results of bench-scale studies suggest that denitrification rates can potentially be increased by an order of magnitude with the addition of ethanol as a carbon substrate. The objective of the study was to investigate the potential of ethanol amendment for enhancing the natural denitrification occurring in the alluvial aquifer. Pilot tests were conducted using the single well, push-pull method and a natural-gradient test. The results showed that the concentration of nitrate decreased, while the concentration of nitrous oxide (a product of denitrification) increased. In addition, changes in aqueous concentrations of sulfate, iron, and manganese indicate the ethanol amendment effected a change in prevailing redox conditions. The results of compound-specific stable isotope analysis for nitrogen indicated that the nitrate concentration reductions were biologically mediated. Continued monitoring after completion of the pilot tests has shown that nitrate concentrations in the injection zone have remained at levels three orders of magnitude lower than the initial values, indicating that the impacts of the pilot tests have been sustained for several months.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗