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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 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Aspects of track-assisted mass

Track-assisted mass is a proxy for jet mass that only uses direction information from charged particles, allowing it to be measured at the Large Hadron Collider with very fine angular resolution. In this paper, we introduce a generalization of track-assisted mass and analyze its performance in both parton shower generators and resummed calculations. For the original track-assisted mass, the track-only mass is rescaled by the charged energy fraction of the jet. In our generalization, the rescaling factor includes both per-jet and ensemble-averaged information, facilitating a closer correspondence to ordinary jet mass. Using the track function formalism in electron-positron collisions, we calculate the spectrum of generalized track-assisted mass to next-to-leading-logarithmic order with leading-order matching. These resummed calculations provide theoretical insight into the close correspondence between track-assisted mass and ordinary jet mass. With the growing importance of jet grooming algorithms, we also calculate track-assisted mass on soft-drop groomed jets.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Global aspects of conformal symmetry and the ANEC in dS and AdS

Starting from the averaged null energy condition (ANEC) in Minkowski we show that conformal symmetry implies the ANEC for a conformal field theory (CFT) in a de Sitter and anti-de Sitter background. A similar and novel bound is also obtained for a CFT in the Lorentzian cylinder. Using monotonicity of relative entropy, we rederive these results for dS and the cylinder. As a byproduct we obtain the vacuum modular Hamiltonian and entanglement entropy associated to null deformed regions of CFTs in (A)dS and the cylinder. A third derivation of the ANEC in dS is shown to follow from bulk causality in AdS/CFT. Finally, we use the Tomita-Takesaki theory to show that Rindler positivity of Minkowski correlators generalizes to conformal theories defined in dS and the cylinder.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Novel aspects of the extended first law of entanglement

Using AdS/CFT an extended first law of entanglement has been previously derived for the vacuum reduced to a ball in Minkowski. The statement not only includes perturbations of the state but also of the conformal field theory (CFT), via variations of the generalized central charge. We clarify some subtleties previously overlooked and use simple arguments to generalize prior derivations to arbitrary gravity theories in the bulk as well as new regions in the boundary CFT. Our construction also applies to two-dimensional bulk theories and admits an interesting extension for a three-dimensional bulk, providing a curious result regarding the thermodynamic volume in extended black hole thermodynamics. We discuss future prospects regarding the extended first law of entanglement.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Universality aspects of quantum corrections to transverse momentum broadening in QCD media

We study non-linear quantum corrections to transverse momentum broadening (TMB) of a fast parton propagating in dense QCD matter in the leading logarithmic approximation. These non-local corrections yield an anomalous super-diffusive behavior characterized by a heavy tailed distribution which is associated with Lévy random walks. Using a formal analogy with the physics of traveling waves, we show that at late times the transverse momentum distribution tends to a universal scaling regime. We derive analytic solutions in terms of an asymptotic expansion around the scaling limit for both fixed and running coupling. We note that our analytic approach yields a good agreement with the exact numerical solutions down to realistic values of medium length. Finally, we discuss the interplay between system size and energy dependence of the diffusion coefficient $\hat{q}$ and its connection with the gluon distribution function that is manifest at large transverse momentum transfer.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Aspects of defects in 3d-3d correspondence

In this paper we study supersymmetric co-dimension 2 and 4 defects in the compactification of the 6d (2, 0) theory of type A N-1 on a 3-manifold M . The so-called 3d-3d correspondence is a relation between complexified Chern-Simons theory (with gauge group SL(N,C) ) on M and a 3d N=2 theory T N [M ]. We study this correspondence in the presence of supersymmetric defects, which are knots/links inside the 3-manifold. Our study employs a number of different methods: state-integral models for complex Chern-Simons theory, cluster algebra techniques, domain wall theory T [SU(N )], 5d N=2 SYM, and also supergravity analysis through holography. These methods are complementary and we find agreement between them. In some cases the results lead to highly non-trivial predictions on the partition function. Our discussion includes a general expression for the cluster partition function, which can be used to compute in the presence of maximal and certain class of non-maximal punctures when N > 2. We also highlight the non-Abelian description of the 3d N=2 T N [M ] theory with defect included, when such a description is available. This paper is a companion to our shorter paper, which summarizes our main results.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Aspects of Galileon non-renormalization

We discuss non-renormalization theorems applying to galileon field theories and their generalizations. Galileon theories are similar in many respects to other derivatively coupled effective field theories, including general relativity and P ( X ) theories. In particular, these other theories also enjoy versions of non-renormalization theorems that protect certain operators against corrections from self-loops. Furthermore, we argue that the galileons are distinguished by the fact that they are not renormalized even by loops of other heavy fields whose couplings respect the galileon symmetry.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Aspects of AdS 2 classification in M-theory: solutions with mesonic and baryonic charges

We construct necessary and sufficient geometric conditions for a class of AdS 2 solutions of M-theory with, at least, minimal supersymmetry to exist. We generalize previous results in the literature for N = (2,0) supersymmetry in AdS 2 to N = (1,0). When the solution can be locally described as AdS 2 × Σ g × SE 7 with Σ g a Riemann surface of genus g and SE 7 a seven-dimensional Sasaki-Einstein manifold, we clarify and unify various solutions present in the literature. In the case of SE 7 = Q 1,1,1 we find a new solution with baryonic and mesonic charges turned on simultaneously.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Interpretation and Diplomacy Aspects of Authority and Care in Imaging Reports

Whereas the creativity and intellectual power of the radiologist are measured against his/her written report, the value of the message will not only be judged by the precision of the medical statement. The same result can be attributed to different words. Numerous common and accidental factors exert influence on the decision on what is said and what is not said, how it is assessed and what is ignored. The less certain a diagnosis is and the less favourable its possible consequences are, the more subtleties and periphrases are to be expected within the report. The decision on the nature and the volume of the written report will not only be taken by the time of recording, but is likewise prepared by the knowledge of the patient’s history and symptoms, the personal relationship to him/her as well as by a set of conditions throughout the inspection of the images. The intuition that accompanies the information transfer in imaging diagnostics does not only explain the differences in volume and depth of diagnosis and differential diagnosis, but also the range of diagnostic and therapeutic recommendations.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Accounting for Environmental Aspects in Water-Chemistry Optimization of the Second Loop of NPP with VVER

A problem in operating NPP with VVER is that waste solutions containing ethanolamine and ammonia from regeneration of ion-exchange filters from the second loop must be processed. The amount of ammonia in the regeneration solutions is equal to 85% of the total amount of the contaminating substances. The water chemistry regime of the second loop without ammonia or with ammonia replaced by dimethylamine is examined. It is shown that the use of dimethylamine makes it possible to increase the duration of the filtration cycle for ion-exchange filters of the purification systems, decrease the concentration of products of corrosion, reduce the environmental impact, and simplify the waste water purification technology.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2018

Applied Aspects of the Study of Thermodynamic Parameters of Oil Disperse Systems

For intensification of oil refining without using secondary processes, thermodynamic parameters of gas condensate and residual fuel oil blends were calculated from experimental investigations involving inverse gas chromatography. Apparently, from thermodynamic parameters of gas condensate and residual fuel oil blend, it is possible to determine the optimal ratio of the components for increasing the yield of light fractions. It is likely that the new colloidal structure of the blend of the disperse system (residual fuel oil) with the homogeneous system (gas condensates) forms via formation of a semicolloidal system followed by restructurization due to intermolecular interaction and dissolution processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Methodical Aspects of the Determination of Carbon Dioxide in Atmosphere Using FTIR Spectroscopy

Monitoring the state of ground-based spectroscopic systems ensures high accuracy of atmospheric gas composition measurements and the possibility of using measurement data for validating satellite measurements and numerical models. Column-averaged carbon dioxide mixing ratios (XCO{sub 2}) can be used to assess the quality of spectroscopic measurements because its content is stable in the atmosphere. The XCO{sub 2} values were retrieved from spectra measured by Fourier transform IR spectrometry (FTIR) using a Bruker 125HR instrument between 2009 and 2017 at the Peterhof station (St. Petersburg, Russia). The total error of the FTIR CO{sub 2} columns retrieval was 4.18 ± 0.02%, with 0.36 ± 0.06% and 4.16 ± 0.02% for random and systematic errors, respectively. The data obtained are compared with model calculations based on long-term observations at the Mauna Loa station. Various schemes solving for the inverse problem were analyzed and compared among themselves, and estimates of empirical random errors in the determination of XCO{sub 2} were obtained. To improve the accuracy of XCO{sub 2} measurements, it is recommended to determine the error of the Fourier-spectrometer phase and the slope of the zero line of the spectrum simultaneously with the atmospheric gas composition measurements taking into account various continuum sources of error.

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

Development of Tailor-Made Superabsorbent Polymers: Review of Key Aspects from Raw Material to Kinetic Model

The ability of superabsorbent polymers (SAP) to absorb and retain a large amount of water and/or aqueous solution enables their applications in areas such as agriculture, medicine and water treatment. This versatility has attracted the attention of researchers interested in developing new materials, especially bio-based polymers. As a result, there are numerous studies reporting different types of monomers and crosslinks to produce SAP. Conversely, in the literature there is a lack of discussion of the modeling approaches to describe SAP production. This paper makes a comprehensive and systematic review of the main issues for the synthesis of new SAP materials: monomer and crosslink types, as well as the kinetic model. A database on the raw materials to produce SAP for the main applications should be useful for those interested in producing new SAP materials. The mathematical model correlates structural properties with the synthesis conditions, thus supporting the development of tailor-made products.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Coupled Thermoelasticity Problem for Multilayer Composite Shells of Revolution. I. Theoretical Aspects of the Problem

On the basis of a general integral form of the variational principle of the least possible dissipation of energy of the nonequilibrium thermodynamics, we deduce a nonclassical nonsteady heat-conduction equation for multilayer polyreinforced shells of any shape. A method for the determination of the integral heat conductivities of reinforced layers is developed and the effective constitutive equations for the description of its thermoelastic behavior are proposed. A nonclassical model of deformation of the multilayer shell and a nonlinear model of distribution of the heat flux along the thickness of the layer are formulated. This allows us to take into account the transverse shear strains and guarantee the conditions of thermomechanical contact of the layers and the conditions of thermomechanical loading on the face surfaces of the shell. We construct a closed system of differential equations with the corresponding initial and boundary conditions for a coupled problem of thermoelastic deformation of layered composite shells and plates.

42 ENGINEERING↗
DOE OSTI2019

Geometric Aspects of Analytic Functions

We study a pair of surfaces associated with a function analytic in a domain G, establish relations between the coefficients of the first (second) fundamental quadratic forms of these surfaces and prove theorems on their invariance under conformal transformations.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

Some Aspects of the Scattering Problem for a System of Three Charged Particles

The question of influence of the spectral neighborhood of an accumulative point of bound energies of a pair subsystem on the structure of eigenfunctions of the continuous spectrum for a system of three charged quantum particles is studied. The unified contribution of pair high-excited states are separated in the coordinate asymptotics of such functions.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Unique & challenging aspects of plutonium metal standards exchange program for actinide measurements

The Los Alamos National Laboratory exchange program is the only program of its kind for the distribution of plutonium (Pu) standards materials with a range of impurity contents to multiple laboratories for destructive measurements of elemental concentration. This paper discusses statistical methods used to address challenges in Pu metal exchange data by way of two case studies. Challenges include how to evaluate a data set when a large fraction of the values are minimum detection limits (MDLs), and how to determine potential outliers with limited in-formation on the true spread of the data.

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

Propagator quantum chemical study of S-cis-(Z)-2-(2-formylethenyl)pyrrole: electronic structure and aspects of intramolecular hydrogen bond manifestation in ionization spectra

For the purpose of investigation of the electronic structures of functionalized pyrroles with potential biological activity the electronic structures and ionization spectra of S-cis-(Z)-2-(2-formylethenyl)pyrrole (FP) were calculated by the propagator quantum chemical method. The calculations were performed using the third-order algebraic diagrammatic construction method (ADC(3)) for one-particle Green´s function (electronic propagator) and the 6–31G** basis set. Going from FP (possessing the intramolecular hydrogen bond H⋯O) to its conformation FPR (without H⋯O bonding), the O1s-ionization energy and the ionization energy of the σ-type lone electron pair orbital of the O atom decrease by ~0.2 eV, which is a consequence of stopping the electron density transfer from the O atom. A strong electron density transfer through the hydrogen bond from the O atom to the NH group occurs in the nitrogen core level ionization spectrum as evidenced by a lower N1s-ionization energy of FP (by ~0.7 eV ) compared to that of FPR. The valence shell ionization spectra of FP and FPR calculated using the ADC(3) method are characterized by a high density of the satellite states. The results obtained indicate that the electronic structures of the compounds of the considered class are characterized by pronounced effects of electron correlation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗