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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 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Shubnikov–de Haas Thermoelectric Field Oscillations in Layered Conductors in the Vicinity of a Topological Lifshits Transition

We have studied the response of a layered conductor with a quasi-two-dimensional electron spectrum and a multisheet Fermi surface (FS) formed by two weakly corrugated cylinders and two planar sheets adjoining these cylinders to nonuniform heating. As a result of action of pressure on the conductor or its doping with impurity atoms, distance Δ{sub p} between the FS cylinder and planar sheets can be reduced to such an extent that conduction electrons begin roaming over these sheets, tunneling from one FS sheet (cavity) to the other. If a conduction electron can visit several times all FS sheets during its mean free time, its motion in the plane orthogonal to the magnetic field becomes finite. In this case, Shubnikov–de Haas oscillations are excited with a period determined by the closed area circumscribed by the electron during its motion in the magnetic-breakdown trajectory in the momentum space. We have calculated the dependence of the thermoelectric field on the magnitude and orientation of a quite strong quantizing magnetic field. In a magnetic field normal to the layers, the cross sections of the cylindrical part of the FS are equidistant from both FS planar sheets. However, this equidistance is violated even for a small deviation of the field from the normal to the layers by angle ϑ, and, at a certain value ϑ{sub k} of this angle, the probability of magnetic breakdown to one of the FS planar sheets can be so low that the electron cannot close the magnetic-breakdown trajectory, and its motion over the other planar sheet with a visit to the FS cylindrical part becomes infinite. In this case, the magnetic-breakdown quantum oscillations of magnetization and all kinetic characteristics of the conductor disappear, and their disappearance is repeated periodically with a change in the slope of the magnetic field to the layers as a function of tanϑ.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

The Effective Hamiltonian Method in the Thermodynamics of Two Resonantly Interacting Quantum Oscillators

We investigate the classical problem of two resonantly interacting oscillators each of which is coupled to “its own” heat bath based on the effective Hamiltonian method and the quantum stochastic differential equation (in contrast to the well-known “global” and “local” approaches). We show that in the second order of the algebraic perturbation theory, each of the oscillators turns out to be also coupled to the “foreign” heat bath. We calculate the steady-state heat flows and prove that there is no heat flow from the cold heat bath to the hot one, as evidenced by some results of the local approach.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

ν{sub μ} → ν{sub e} oscillations search in the OPERA experiment

The tracking capabilities of the OPERA detector allow to reconstruct τ-leptons and electrons. It gives a possibility to observe ν{sub μ} → ν{sub τ} oscillations in the appearance mode and to study ν{sub μ} → ν{sub e} oscillations in the ν{sub μ} CNGS beam. Current results on ν{sub μ} → ν{sub e} channel in the three-flavour mixing model are presented. The same data allow to constrain the presence of additional sterile neutrino states. The analysis of the full 2008–2012 OPERA data set and work on its improvement are going on. Details of the achievements are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Discovery of ν{sub μ} → ν{sub τ} oscillations in the OPERA experiment

The OPERA experiment was designed to search for ν{sub μ} → ν{sub τ} oscillations in appearance mode, i.e. by detecting the τ leptons produced in charge current ν{sub τ} interactions. The experiment took data from 2008 to 2012 in the CNGS beam. Five observed ν{sub τ} candidates together with low background 0.25 ± 0.05 allow to assess the discovery of ν{sub μ} → ν{sub τ} oscillations in appearance mode with significance larger than 5σ.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Cascades from primary gamma rays and nuclei as a source of background in searches for oscillations between photons and axion-like particles

Methods: of searching for oscillations of photons to axion-like particles (γ → ALP) in spectra of extragalactic sources are considered. It is shown that the secondary component from the cascades initiated by primary gamma rays or nuclei can produce an appreciable background in searches for ALPs in the optically thick region of the spectrum. Experiments with a high energy threshold (~1 TeV and higher) are insufficient for searching for γ → ALP oscillations; low-energy instruments (E < 100 GeV) like CTA should also be used.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Sensitivity of Experiments to Oscillation Parameters

The paper describes the capabilities of the three experiments on the search for oscillations on a short baseline—BEST, SOX, and DANSS. It is shown that only the first two experiments have the capabilities for localization of the oscillation parameters.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Oscillations of the Degree of Circular Polarization in the Optical Spin Hall Effect

The optical spin Hall effect appears when elastically scattered exciton polaritons couple to an effective magnetic field inside of quantum wells in semiconductor microcavities. Theory predicts an oscillation of the pseudospin of the exciton polaritons in time. Here, we present a detailed analysis of momentum space dynamics of the exciton polariton pseudospin. Compared to what is predicted by theory, we find a higher modulation of the temporal oscillations of the pseudospin. We attribute the higher modulation to additional components of the effective magnetic field which have been neglected in the foundational theory of the optical spin Hall effect. Adjusting the model by adding non-linear polariton-polariton interactions, we find a good agreement in between the experimental results and simulations.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Coupled Electronic–Nuclear Magnetostatic Oscillations in Magnetic Materials

Magnetization dynamics in spheroidal ferromagnetic samples is studied theoretically. It is shown that, in a magnetostatic approximation, electronic-nuclear magnetostatic modes with a discrete spectrum of eigen oscillations exist in such samples. The structure and the field dependence of the frequencies of these oscillations are substantially dependent on the parameter of the spheroid shape that is the ratio of it’s axes and also on the external magnetic field value. In a certain region of values of these parameters, the dependence of the eigenfrequencies of the system on them becomes nontrivial. The external field strength and the sample shape determine not only the eigenfrequencies in the system, but also the number of the eigenmodes. In addition, for each of the eigenmodes, there exists a “forbidden” region of magnetic fields and shape parameters in which this mode cannot be observed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

On Transient Time Reduction of a 2.4 GHz Relativistic Traveling Wave Oscillator with a Hollow Slow Wave System

The decrease in the transient time in a relativistic microwave traveling wave oscillator, in which the interaction is carried out between the relativistic electron beam and the fundamental harmonic of the forward-traveling electromagnetic wave slowed down to the speed of light in the hollow slow wave system system, has been numerically and experimentally demonstrated. It is shown that in this mode a high beam-to-wave coupling impedance up to ≈10 Ω is achieved, which ensures reduction of the transient time. In the experiment, a microwave peak power of 210 ± 30 MW at a frequency of 2.45 GHz in a guiding magnetic field of 0.16 T was obtained. The efficiency of the oscillator to convert the power of the electron beam into microwave power was 17 ± 3%. At the beam current pulse duration of about 50 ns the microwave pulse duration was about 20 ns and the transient time was about 22 ns.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Megawatt pulses from an all-fiber and self-starting femtosecond oscillator

Mamyshev oscillators produce high-performance pulses, but technical and practical issues render them unsuitable for widespread use. Here we present a Mamyshev oscillator with several key design features that enable self-starting operation and unprecedented performance and simplicity from an all-fiber laser. The laser generates 110 nJ pulses that compress to 40 fs and 80 nJ with a grating pair. The pulse energy and duration are both the best achieved by a femtosecond all-fiber laser to date, to our knowledge, and the resulting peak power of 1.5 MW is 20 times higher than that of prior all-fiber, self-starting lasers. Finally, the simplicity of the design, ease of use, and pulse performance make this laser an attractive tool for practical applications.

47 OTHER INSTRUMENTATION↗
DOE OSTI2014

Reference Model 6 Cost Breakdown (RM6: Oscillating Water Column)

Contains the Reference Model 6 (RM6) spreadsheets with the cost breakdown structure (CBS) for the levelized cost of energy (LCOE) calculations for a single RM6 device and multiple unit arrays. These spreadsheets are contained within an XLSX file and a spreadsheet editor such as Microsoft Excel is needed to open the file. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 6 (RM6) is a Backward Bent Duct Buoy (BBDB), which is a type of oscillating water column wave energy converter. First proposed by Masuda, the BBDB design is a floating Oscillating Water Column (OWC) device that consists of an air chamber, an L-shaped duct, bow and stern buoyancy modules, and a power take-off (PTO) composed of a Wells air turbine and a generator. This L- shaped device opens to the ocean downstream from the wave propagation direction. Power is produced by the motion of the wave, which causes the ambient pressure in the air chamber to vary thereby forcing air to flow through the Wells turbine. The reference wave energy resource for RM6 was developed from site information collected near Eureka, in Humboldt County, California.

16 TIDAL AND WAVE POWER↗
DOE OSTI2014

Reference Model 5 Full Scale Geometry (RM5: Oscillating Surge Flap)

Contains the Reference Model 5 (RM5) full scale geometry files of the Oscillating Surge Flap, developed by the Reference Model Project (RMP). These full scale geometry files are saved as SolidWorks assembly, IGS, and STEP files, and require a CAD program to view. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 5 (RM5) is a type of floating, oscillating surge wave energy converter (OSWEC) that utilizes the surge motion of waves to generate electrical power. The reference wave energy resource for RM5 was measurement data from a National Data Buoy Center (NDBC) buoy near Eureka, in Humboldt County, California. The flap was designed to rotate against the supporting frame to convert wave energy into electrical power from the relative rotational motion induced by incoming waves. The RM5 design is rated at 360 kilowatts (kW), uses a flap of 25 m in width and 19 m in height (16 m in draft), and the distance from the top of the water surface piercing flap to the mean water surface (freeboard) is 1.5 m. The flap is connected to a shaft with a 3-m diameter that rotates against the supporting frame. The supporting frame is assumed to have an outer diameter of 2 m, and the total length of the device structure is 45 m. The RM5 OSWEC was designed for deep-water deployment, at depths between 50 m and 100 m, and was tension-moored to the seabed.

16 TIDAL AND WAVE POWER↗
DOE OSTI2015

Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

16 TIDAL AND WAVE POWER↗
DOE OSTI2016

Atmospheric Radiation Measurement Madden-Julian Oscillation Investigation Experiment Field Campaign Report

Every 30–90 days during the Northern Hemisphere winter, the equatorial tropical atmosphere experiences pulses of extraordinarily strong deep convection and rainfall. This phenomenon is referred to as the Madden–Julian Oscillation, or MJO, named after the scientists who identified this cycle. The MJO significantly affects weather and rainfall patterns around the world (Zhang 2013). To improve predictions of the MJO—especially about how it forms and evolves throughout its lifecycle—an international group of scientists collected an unprecedented set of observations from the Indian Ocean and western Pacific region from October 2011 through March 2012 through several coordinated efforts. The coordinated field campaigns captured six distinct MJO cycles in the Indian Ocean. The rich set of observations capturing several MJO events from these efforts will be used for many years to study the physics of the MJO. Here we highlight early research results using data from the Atmospheric Radiation Measurement (ARM) Madden-Julian Oscillation Investigation Experiment (AMIE), sponsored by the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

A Ruler To Measure The Universe : Probing Dark Energy with Baryon Acoustic Oscillations

Understanding the nature of the dark energy that is responsible for roughly 70% of the energy content of the Universe and is causing the accelerated expansion of the Universe is one of the foremost problems in cosmology today. This grant supported the development of the Baryon Acoustic Oscillation (BAO) technique to measure the expansion rate of the Universe and thereby constrain the properties of the dark energy. The primary achievement over the course of the grant was the development of the reconstruction technique for BAO which enhances the constraining power of this method. At the start of this grant, this reconstruction technique, although theoretically studied, had not been applied to data. The work supported by this grant helped make reconstruction a standard technique in the analysis of BAO data. This grant also supported analyses using the Baryon Oscillation Spectroscopic Survey (BOSS, supported by DOE), as well as theoretical work in preparation for the next generations of surveys, most notably the Dark Energy Spectroscopic Instrument (DESI).

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

FY2018 Discovery Through Situational Awareness: Anomalies, Oscillations, and Classification

This technical report is a summary of work performed under the DOE GMLC program under the task titled “Discovery through Situational Awareness”. The focus of this work was to apply big data, statistical techniques to PMU data to do the following: 1) baseline PMU data and find anomalies with a focus on phase angle pairs, 2) identify the frequencies of dominant modal oscillations between different parts of a power system, and 3) identify and classify frequency events in PMU data. This work was performed on PMU data from the Western Interconnect. Many of these algorithms will be applied to wide area phase angle pair data on the Eastern Interconnect in a tool called ESAMS (Eastern Interconnect Situational Awareness Monitoring System). ESAMS was built by EPG (Electric Power Group) and PNNL and is currently being installed on the Eastern Interconnect. The results discussed in this report were made from 14 PMUs from data ranging from Oct 2016 to May 2018. The PMU data were measured 60 times each second. Fourteen phase angle pairs were included, with reactive and active power being calculated at 14 sites. All results have been de-identified for this report. The methodologies applied in the ESAMS tool are described in Section 2. A baseline of PMU data is created using the last 120 days of data. This baseline describes typical behavior as understood from the data. The baseline is then applied to the next day’s data and anomalies from that baseline are identified. Plots are created to help describe what is anomalous during that specific moment in time. These algorithms are currently being installed on the Eastern Interconnect. FY19 work will include discussing the results and findings from the ESAMS tool. A new method of identifying the frequencies of dominant modal oscillations between different parts of a power system is described in Section 3. A list of 199 frequency events provided by Bonneville Power Administration were used to create algorithms to detect frequency events and to create classification rules that can be used to identify future frequency events. Section 4 discusses the results the performance of 7 different event detection, clustering-based methods. Accuracy percentages ranged from 93.59% to 99.16%, with most methods being very fast. GBM (Gradient Boosting Machine) performed well and quickly. These 7 different methods were also tested to determine how well each built classification rules on training data and then applied those rules to identify future frequency events. Accuracy percentages ranged from 89.09% to 99.9%, with all methods performing quickly. GLM (General Linear Model) was viewed as the top performer when considering accuracy and processing time. Because the list of events consisted of 80% of them as active power events and only 20% as faults, all methods struggled to identify events as faults. Small faults were especially difficult to identify. A separate algorithm was created to help with this. Additional work will be done in FY19 on event detection using more data and more events and refinements to the methods.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2018

Oscillations in the Mechatronic System of a Multi-Stand Rolling Mill

The mechatronic system of the DUO-300 rolling mill is analyzed. The influence of the roller’s linear velocity on the distribution of frictional forces in the rolling region is studied. A nonlinear relation is found between the load and the roller speed. The conditions of self-oscillation in rolling are determined. Methods of damping the self-oscillation are considered.

42 ENGINEERING↗
DOE OSTI2021

First Digit Oscillations

The frequency of the first digits of numbers drawn from an exponential probability density oscillate around the Benford frequencies. Analysis, simulations and empirical evidence show that datasets must have at least 10,000 entries for these oscillations to emerge from finite-sample noise. Anecdotal evidence from population data is provided.

97 MATHEMATICS AND COMPUTING↗