Patterns of symmetry breaking in chiral QCD
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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Results for “COMPOSITE MODELS”
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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Search for resonances in the mass distribution of jet pairs with one or two jets identified as b -jets in proton-proton collisions at s = 13 TeV with the ATLAS detector
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Nonperturbative investigations of SU(3) gauge theory with eight dynamical flavors
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Predicting the superpartner spectrum from partially composite supersymmetry
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Partial compositeness and baryon matrix elements on the lattice
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Active to Sterile Neutrino Mixing Limits from Neutral-Current Interactions in MINOS
Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of 7.07x10{sup 20} protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of 754{+-}28(stat){+-}37(syst) for oscillations among three active flavors. The fraction f{sub s} of disappearing {nu}{sub {mu}} that may transition to {nu}{sub s} is found to be less than 22% at the 90% C.L.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
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↗
Constraints on the Fundamental String Coupling from B-Mode Experiments
We study signatures of cosmic superstring networks containing strings of multiple tensions and Y junctions, on the cosmic microwave background (CMB) temperature and polarization spectra. Focusing on the crucial role of the string coupling constant g{sub s}, we show that the number density and energy density of the scaling network are dominated by different types of string in the g{sub s}{approx}1 and g{sub s}<<1 limits. This can lead to an observable shift in the position of the B-mode peak--a distinct signal leading to a direct constraint on g{sub s}. We forecast the joint bounds on g{sub s} and the fundamental string tension {mu}{sub F} from upcoming and future CMB polarization experiments, as well as the signal to noise in detecting the difference between B-mode signals in the limiting cases of large and small g{sub s}. We show that such a detectable shift is within reach of planned experiments.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
No Collective Neutrino Flavor Conversions during the Supernova Accretion Phase
We perform a dedicated study of the supernova (SN) neutrino flavor evolution during the accretion phase, using results from recent neutrino radiation hydrodynamics simulations. In contrast to what was expected in the presence of only neutrino-neutrino interactions, we find that the multiangle effects associated with the dense ordinary matter suppress collective oscillations. The matter suppression implies that neutrino oscillations will start outside the neutrino decoupling region and therefore will have a negligible impact on the neutrino heating and the explosion dynamics. Furthermore, the possible detection of the next galactic SN neutrino signal from the accretion phase, based on the usual Mikheyev-Smirnov-Wolfenstein effect in the SN mantle and Earth matter effects, can reveal the neutrino mass hierarchy in the case that the mixing angle {theta}{sub 13} is not very small.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Constraining the P 30 ( p , γ ) S 31 Reaction Rate in ONe Novae via the Weak, Low-Energy, β -Delayed Proton Decay of Cl 31
The 30 P(p,γ) 31 S reaction plays an important role in understanding the nucleosynthesis of A ≥ 30 nuclides in oxygen-neon novae. The Gaseous Detector with Germanium Tagging was used to measure 31 Cl β-delayed proton decay through the key J π = 3/2 + , 260-keV resonance. The intensity $I$$^{260}_{βp}$ = $8.3$$^{+1.2}_{–0.9}$ × 10 –6 represents the weakest β-delayed, charged-particle emission ever measured below 400 keV, resulting in a proton branching ratio of Γ p /Γ = $2.5$$^{+0.4}_{–0.3}$ × 10 –4 . Here, by combining this measurement with shell-model calculations for Γγ and past work on other resonances, the total 30 P(p,γ) 31 S rate has been determined with reduced uncertainty. The new rate has been used in hydrodynamic simulations to model the composition of nova ejecta, leading to a concrete prediction of 30 Si: 28 Si excesses in presolar nova grains and the calibration of nuclear thermometers.
79 ASTRONOMY AND ASTROPHYSICS↗
PMU-Based Monitoring and Mitigation of Delayed Voltage Recovery Using Admittances
This project analyzes the delayed voltage recovery phenomenon by simplifying the Western Electricity Coordinating Council (WECC) composite load model using the load admittance and the thermal relay dynamics. From this analysis, a closed form expression approximating the recovery time is derived and the key load parameters impacting the behavior of voltage recovery are identified. A monitoring scheme based on the measured load admittance is then proposed to detect the onset of stalling, even in the presence of voltage oscillations, and estimate the duration of the delayed voltage recovery. A mitigation scheme utilizing smart thermostats and offline learning is also derived to ensure that the voltage recovers to the pre-contingency voltage within a specified time. Both the monitoring and mitigation schemes only need local measurements at a substation making them promising for online applications. Results for the monitoring and mitigation schemes are described in detail for the IEEE 162 bus system validating the various assumptions used for the analysis and establishing the connection between the delayed voltage recovery phenomenon and load admittance.
24 POWER TRANSMISSION AND DISTRIBUTION↗
Profiling and Predicting Application Performance on the Cloud
Cloud providers continue to expand and diversify their collection of leasable resources to meet the needs of an increasingly wide range of applications. While this flexibility is a key benefit of the cloud, it also creates a complex landscape in which users are faced with many resource choices for a given application. Suboptimal selections can both degrade performance and increase costs. Given the rapidly evolving pool of resources, it is infeasible for users alone to select instance types; instead, automated methods are needed to simplify and guide resource provisioning. Here we present a method for the automatic prediction of application performance on arbitrary cloud instances. We combine offline and online profiling approaches, using historical data gathered from non-cloud environments and targeted profiling runs on cloud environments to create a composite application model that can predict run times on a given cloud instance type for a given input data size. We demonstrate average error of 17.2% across nine applications used in production bioinformatics workflows. Finally, we evaluate an experiment design approach to explore the trade-off between the cost of profiling and the accuracy of our models. Using this approach, with no prior knowledge, we show that using 4 selectively chosen experiments we can achieve performance within 30% of a model trained using all instance types.
Cloud profiling↗
Application of Linear Additive Conditions for Near-Infrared Diffuse Reflectance Absorption Spectroscopy
Determining the homogeneity of material mixing in real time during product processing is critical for quality control. According to the Kubelka–Munk (K-M) function of diffuse reflectance absorption spectrum, absorbance (A) is approximately linear with the content of the components when the sample scattering coefficient (S) is in a certain range. The S is determined by the particle size of powder samples. Therefore, this study determined particle size ranges that satisfy linear additivity in near-infrared diffuse reflectance spectroscopy (NIRDRS). Thus, the proposed NIRDRS analysis technique can be used to determine the homogeneity of material mixes or analyze the percentages of the components in the mixture. In this study, vitamin B3 and vitamin C were used for preparing mixed samples with varying percentages. The experimental results revealed that linear additivity is satisfied when the powder particle size is in the range of less than 280, 280–450, and 450–900 μm. When the confidence level is 0.01, the actual mixed spectra are not significantly different from the “simulated mixed spectra” constructed by linear addition, with their relative deviations less than 1.08%. The absolute errors of the actual and analytic percentages were within 2.98% for each component in the mixtures. The above conclusions also hold for sorghum, which has a complex material composition. Statistical models cannot analyze the percentages of components in the mixture. In contrast, linear addition and direct calibration approach avoids the use of a large number of samples for statistical modeling and analyze the percentages of mixed samples. Meanwhile, it can be used to discriminate and analyze the material mixing uniformity by building a mechanistic model.
Feng, Zhiyue↗
In situ analysis of potential distribution in Li-ion Batteries
This project accomplished the goal of developing an in situ method of imaging and analysis of local potential distribution in model and composite Li-ion electrodes during charge/discharge process. A scanning probe microscope was used to detect and image potential differences within the composite LCO electrode and the corresponding variations of the active material local state of charge.
25 ENERGY STORAGE↗
UNREVIEWED DISPOSAL QUESTION EVALUATION: Development of Inventory Screening Limits for the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada
This Unreviewed Disposal Question Evaluation estimates the inventory of specific radionuclides that represent negligible risk for the Area 5 Radioactive Waste Management Site on the Nevada National Security Site. Radionuclides exceeding these screening limits are candidates for entry into the performance assessment and composite analysis model. Screening limits are developed for an expanded list of radionuclides. The screening limits are estimated as the total site inventory that would cause a receptor to receive 1/1000th of the 0.1 milliseivert (mSv) air pathway or 0.25 mSv all-pathways performance objectives. The receptor is assumed to be exposed to undiluted waste for a period of one year.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Materials Challenges and Opportunities for Energy Generation, Conversion, Delivery, and Storage (Applied Energy Tri-Laboratory Consortium Workshop Report)
This report documents the outcomes of the Tri-Laboratory Materials Workshop that was held July 31 and August 1, 2019 to begin addressing the needs, opportunities, and challenges associated with the development, fabrication, and testing of the needed materials and components for integrated hybrid energy systems (i.e., incorporating nuclear, fossil, and renewables for electric and thermal applications). This was accomplished by assembling the research program leads and principal investigators at Idaho National Laboratory (INL), National Energy Technology Laboratory (NETL), and National Renewable Energy Laboratory (NREL), who support the research and development of new technology and system integration. The team then identified and prioritized key materials development needs. This effort was intended to enhance communications and synergy among the Tri-Lab partners. Advanced functional and structural materials are central to transformative energy technologies for energy generation, conversion, delivery, and storage. With that in mind, the workshop focused on identifying and assessing the foundational materials research needs at both the basic and applied levels. Materials challenges include the ability to withstand harsh environments, such as high temperatures and pressures, corrosion, oxidation, or irradiation while maintaining flexible mission profiles and long service lifespans. Advanced energy system material challenges and needs range from materials for the capture, upgrading/concentration, storage, and delivery of low-grade heat to materials for high temperature environments that involve liquid metals, molten salt, and very high temperature gas heat delivery and storage systems. Material improvements are needed for hybrid energy systems due to accelerated corrosion and stress-fatigue failure of materials and equipment, which results from increased frequency and amplitude of thermal, mechanical, and electrical cycling of systems components. Multifunctional materials are needed for high temperature solid-oxide fuel cells, advanced electrochemical reactors, and in-process separation. Relative to materials manufacturing, application of advanced additive and subtractive methods need to be understood to develop both thin-layer homogenous materials and materials of graded composition. Materials modeling and machine learning will be critical to accelerate the design and production of power electronics, and nuclear reactor materials and fuel, as well as to gain an understanding of beneficial materials phenomena or deleterious microstructure evolution. There is also a need for standardized models, computational structures, data reporting protocols and modeling tools across the three laboratories. This would allow consistent results, analysis, and data sharing. Combining computational capabilities between the three laboratories (e.g., hardware, software) would greatly increase computational capabilities and throughput. The workshop identified the need for laboratories to anticipate and address problems that will occur during scale-up. Laboratory work must connect with industry to ensure that research focuses on processes that are scalable and marketable. Industry input and perspective are essential to guide laboratory research to meet these requirements and deploy new technology in industrial demonstrations. Another aspect of scale-up is the integration of multiple systems since new challenges often arise at the subsystem interfaces. Establishing a scale-up manufacturing demonstration/pilot plant, potentially as an industrial user facility, would be beneficial to the laboratories and industry. That modular scale-up manufacturing demonstration/pilot plant would allow researchers to find and resolve interface problems that cannot be identified by focusing only on individual parts. Communication exchanges among the organizers, attendees, and workshop survey responses indicate that the workshop was successful in achieving its goal to identify key technology gaps and research needs. Strong positive feedback was received on the sharing of ideas, capabilities, talent, and passion to move forward on the materials-related action items.
36 MATERIALS SCIENCE↗