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At least 1,639 records · Page 91

All sources NASA NTRS DOE OSTI

DOE OSTI2015

New Generator Technology

New generator technology project is driven by the need to be able to remotely deploy generator technology where it is needed, when it is needed. Both the military and aid programs that provide assistance after disasters could use the ability to deploy energy generation that fits the needs of the situation. Currently, pre-specified generators are deployed, sometime more than half way around the world to provide electricity. Through our Phase-I to Phase III DARPA grant, we will provide a mechanism where a 3d print station and raw materials could be shipped to a deployment site and remotely deployed personnel. These remote personnel can collaborate with engineers at a home location where 3d print plans can be optimized for the remote purpose. The plans can then be sent electronically to the remote location for printing, much like NASA sent the plans for a socket wrench to the International Space Station for printing in . If multiple generators need to be deployed at different remote locations, within miles of each other the printer rig can be moved to print the generators where they are needed. 3d printing is growing in the field of manufacturing. 3d printing has matured to the point where many types of materials are now available for many types of manufacturing. Both magnetic and electrically conductive material materials have recently been developed which can now lead to 3d printing of engines and generators. Our project will provide a successful printer rig that can be remotely deployed, to print a generator design in the field as well as provide a process for deploying the printed generator as well. This Systems Engineering Management Plan(SEMP) will provide the planning required for a Phase I DARPA grant that may also include goals for Phase II and Phase II grants. The SEMP provides a proposed project schedule, references, system engineering processes, specialty engineering system deployment and product support sections. Each section will state how our company will provide the necessary services to make this project succeed.

3D printing, manufacturing, generator technology, ↗

NASA NTRS1978

Optimal guidance and control for investigating aircraft noise-impact reduction

A methodology for investigating the reduction of community noise impact is reported. This report is concerned with the development of two models to provide data: a guidance generator and an aircraft control generator suitable for various current and advanced types of aircraft. The guidance generator produces the commanded path information from inputs chosen by an operator from a graphic scope display of a land-use map of the terminal area. The guidance generator also produces smoothing at the junctions of straight-line paths.The aircraft control generator determines the optimal set of the available controls such that the aircraft will follow the commanded path. The solutions for the control functions are given and shown to be dependent on the class of aircraft to be considered, that is, whether the thrust vector is rotatable and whether the thrust vector affects the aerodynamic forces. For the class of aircraft possessing a rotatable thrust vector, the solution is redundant; this redundancy is removed by the additional condition that the noise inpact be minimized. Information from both the guidance generator and the aircraft control generator is used by the footprint program to construct the noise footprint.

Stewart, E. C.↗

NASA NTRS2000

Parametric Study of Radiator Concepts for a Stirling Radioisotope Power System Applicable to Deep Space Mission

The Department of Energy (DOE) and the NASA Glenn Research Center are developing a Stirling converter for an advanced radioisotope power system to provide spacecraft onboard electric power for NASA deep space missions. This high-efficiency converter is being evaluated as an alternative to replace the much lower efficiency radioisotope thermoelectric generator (RTG). The current power requirement (six years after beginning of mission (BOM) for a mission to Jupiter) is 210 W(sub e) (watts electric) to be generated by two separate power systems, one on each side of the spacecraft. Both two-converter and four-converter system designs are being considered, depending on the amount of required redundancy.

Juhasz, Albert J.↗

DOE OSTI2020

Detecting faults in wind turbines

A wind turbine generator fault detection method is described. The method includes obtaining a first signal from a generator of a wind turbine and a second signal from a vibration sensor coupled to the wind turbine, the first signal representing an output current of the generator, and the second signal being a time-sampled signal representing vibrations of a bearing in the wind turbine. Determining a shaft rotation frequency signal from the first signal, the shaft rotation frequency signal representing a time-varying rotational speed of a shaft of the wind turbine. Resampling an envelope of the second signal based on the shaft rotation frequency signal to provide a third signal, the third signal being an angular sampled signal. Detecting, by the at least one processor, a fault in the bearing of the wind turbine by identifying a characteristic signature of a bearing fault in the third signal.

Qiao, Wei↗

DOE OSTI2022

Detecting faults in wind turbines

Qiao, Wei↗

DOE OSTI2014

Determining heavy metals in spent compact fluorescent lamps (CFLs) and their waste management challenges: Some strategies for improving current conditions

Highlights: • Heavy metals in spent compact fluorescent lamps (CFLs) determined. • Current waste management condition of CFLs in Iran assessed. • Currently, waste of CFLs is disposed by municipal waste stream in waste landfills. • We propose extended producer responsibility (EPR) for CFLs waste management. - Abstract: From environmental viewpoint, the most important advantage of compact fluorescent lamps (CFLs) is reduction of green house gas emissions. But their significant disadvantage is disposal of spent lamps because of containing a few milligrams of toxic metals, especially mercury and lead. For a successful implementation of any waste management plan, availability of sufficient and accurate information on quantities and compositions of the generated waste and current management conditions is a fundamental prerequisite. In this study, CFLs were selected among 20 different brands in Iran. Content of heavy metals including mercury, lead, nickel, arsenic and chromium was determined by inductive coupled plasma (ICP). Two cities, Tehran and Tabriz, were selected for assessing the current waste management condition of CFLs. The study found that waste generation amount of CFLs in the country was about 159.80, 183.82 and 153.75 million per year in 2010, 2011 and 2012, respectively. Waste generation rate of CFLs in Iran was determined to be 2.05 per person in 2012. The average amount of mercury, lead, nickel, arsenic and chromium was 0.417, 2.33, 0.064, 0.056 and 0.012 mg per lamp, respectively. Currently, waste of CFLs is disposed by municipal waste stream in waste landfills. For improving the current conditions, we propose by considering the successful experience of extended producer responsibility (EPR) in other electronic waste management. The EPR program with advanced recycling fee (ARF) is implemented for collecting and then recycling CFLs. For encouraging consumers to take the spent CFLs back at the end of the products’ useful life, a proportion of ARF (for example, 50%) can be refunded. On the other hand, the government and Environmental Protection Agency should support and encourage recycling companies of CFLs both technically and financially in the first place.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

Tunable orbital angular momentum in high-harmonic generation

Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light–matter interactions, and the disentanglement and independent control of the intrinsic and extrinsic components of the photon’s angular momentum at short-wavelengths. Finally, the methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2017

MC 2 -3: Multigroup Cross Section Generation Code for Fast Reactor Analysis

This paper presents the methods and performance of the MC2 -3 code, which is a multigroup cross-section generation code for fast reactor analysis, developed to improve the resonance self-shielding and spectrum calculation methods of MC2 -2 and to simplify the current multistep schemes generating region-dependent broad-group cross sections. Using the basic neutron data from ENDF/B data files, MC2 -3 solves the consistent P1 multigroup transport equation to determine the fundamental mode spectra for use in generating multigroup neutron cross sections. A homogeneous medium or a heterogeneous slab or cylindrical unit cell problem is solved in ultrafine (2082) or hyperfine (~400 000) group levels. In the resolved resonance range, pointwise cross sections are reconstructed with Doppler broadening at specified temperatures. The pointwise cross sections are directly used in the hyperfine group calculation, whereas for the ultrafine group calculation, self-shielded cross sections are prepared by numerical integration of the pointwise cross sections based upon the narrow resonance approximation. For both the hyperfine and ultrafine group calculations, unresolved resonances are self-shielded using the analytic resonance integral method. The ultrafine group calculation can also be performed for a two-dimensional whole-core problem to generate region-dependent broad-group cross sections. Verification tests have been performed using the benchmark problems for various fast critical experiments including Los Alamos National Laboratory critical assemblies; Zero-Power Reactor, Zero-Power Physics Reactor, and Bundesamt für Strahlenschutz experiments; Monju start-up core; and Advanced Burner Test Reactor. Verification and validation results with ENDF/B-VII.0 data indicated that eigenvalues from MC2 -3/DIF3D agreed well with Monte Carlo N-Particle5 MCNP5 or VIM Monte Carlo solutions within 200 pcm and regionwise one-group fluxes were in good agreement with Monte Carlo solutions.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2018

Power Generation from a Radiative Thermal Source Using a Large-Area Infrared Rectenna

Electrical power generation from a moderate-temperature thermal source by means of direct conversion of infrared radiation is important and highly desirable for energy harvesting from waste heat and micropower applications. Here, we demonstrate direct rectified power generation from an unbiased large-area nanoantenna-coupled tunnel diode rectifier called a rectenna. Using a vacuum radiometric measurement technique with irradiation from a temperature-stabilized thermal source, a generated power density of 8 nW / cm 2 is observed at a source temperature of 450°C for the unbiased rectenna across an optimized load resistance. The optimized load resistance for the peak power generation for each temperature coincides with the tunnel diode resistance at zero bias and corresponds to the impedance matching condition for a rectifying antenna. Current-voltage measurements of a thermally illuminated large-area rectenna show current zero crossing shifts into the second quadrant indicating rectification. Photon-assisted tunneling in the unbiased rectenna is modeled as the mechanism for the large short-circuit photocurrents observed where the photon energy serves as an effective bias across the tunnel junction. Furthermore, the measured current and voltage across the load resistor as a function of the thermal source temperature represents direct current electrical power generation.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2022

First Measurement of Differential Charged Current Quasi-Elastic-Like $\nu_{\mu}$ Argon Scattering Cross Sections with the MicroBooNE Detector

Current and future generation neutrino oscillation experiments aim towards a high-precisionmeasurement of the oscillation parameters, which requires an unprecedented understanding ofneutrino-nucleus scattering. Charged-current quasi-elastic (CCQE) scattering is the process inwhich the neutrino produces a charged lepton and removes a single intact nucleon from the nu-cleus without producing any additional particles. For existing and forthcoming accelerator–based neutrino experiments, CCQE interactions are either the dominant process or part of the signal.MicroBooNE is the first liquid argon time projection chamber (LArTPC) commissioned as part ofthe Short Baseline Neutrino (SBN) program at Fermilab and its excellent particle reconstructioncapabilities allow the detection of neutrino interactions using exclusive final states, which will playa crucial role in the success of future kiloton LArTPC detectors such as DUNE. This talk willpresent the first measurement of exclusive νμ-Ar CCQE–like flux integrated total and differentialcross sections using single proton knock–out interactions recorded by the MicroBooNE LArTPCdetector, which has comparable acceptance to deuterium Bubble Chambers.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2016

Growing America's Energy Future

The emerging U.S. bioenergy industry provides a secure and growing supply of transportation fuels, biopower, and bioproducts produced from a range of abundant, renewable biomass resources. Bioenergy can help ensure a secure, sustainable, and economically sound future by reducing U.S. dependence on foreign oil, developing domestic clean energy sources, and generating domestic green jobs. Bioenergy can also help address growing concerns about climate change by reducing greenhouse gas emissions to create a healthier environment for current and future generations.

Growing America's Energy Future↗

NASA NTRS2016

Electron Scale Structures and Magnetic Reconnection Signatures in the Turbulent Magnetosheath

Collisionless space plasma turbulence can generate reconnecting thin current sheets as suggested by recent results of numerical magnetohydrodynamic simulations. The Magnetospheric Multiscale (MMS) mission provides the first serious opportunity to verify whether small ion-electron-scale reconnection, generated by turbulence, resembles the reconnection events frequently observed in the magnetotail or at the magnetopause. Here we investigate field and particle observations obtained by the MMS fleet in the turbulent terrestrial magnetosheath behind quasi-parallel bow shock geometry. We observe multiple small-scale current sheets during the event and present a detailed look of one of the detected structures. The emergence of thin current sheets can lead to electron scale structures. Within these structures, we see signatures of ion demagnetization, electron jets, electron heating, and agyrotropy suggesting that MMS spacecraft observe reconnection at these scales.

Yordanova, E.↗

DOE OSTI2015

Procedure to Generate the MPACT Multigroup Library

The CASL neutronics simulator MPACT is under development for the neutronics and T-H coupled simulation for the light water reactor. The objective of this document is focused on reviewing the current procedure to generate the MPACT multigroup library. Detailed methodologies and procedures are included in this document for further discussion to improve the MPACT multigroup library.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2024

Circularly Polarized Attosecond Pulses Enabled by an Azimuthal Phase and Polarization Grating

High-harmonic generation (HHG) is an extreme nonlinear optical process that can map the properties of an infrared driving laser beam onto short wavelength attosecond pulse trains. However, current techniques for generating circularly polarized high harmonics for probing magnetic materials and chiral systems have limitations: two-color collinear counter-rotating driving lasers result in a low cutoff photon energy, while single-color non-collinear counter-rotating schemes suffer from low conversion efficiency. In this work, we generate circularly polarized attosecond pulse trains by using a structured laser driver which has a rotating polarization and phase grating along the azimuthal coordinate. Furthermore, our experimental and numerical results demonstrate the production of left and right circularly polarized harmonics, which naturally separate upon propagation. Our approach uses a single laser color in a collinear geometry, that can be scaled for high efficiency. Simulations show this scheme can extend into the soft x-ray region when driven by mid-infrared driving lasers, while preserving the same high phase-matching cutoff photon energy as for linearly-polarized high harmonics.

attosecond science↗

DOE OSTI2015

Spin orbit torque based electronic neuron

A device based on current-induced spin-orbit torque (SOT) that functions as an electronic neuron is proposed in this work. The SOT device implements an artificial neuron's thresholding (transfer) function. In the first step of a two-step switching scheme, a charge current places the magnetization of a nano-magnet along the hard-axis, i.e., an unstable point for the magnet. In the second step, the SOT device (neuron) receives a current (from the synapses) which moves the magnetization from the unstable point to one of the two stable states. The polarity of the synaptic current encodes the excitatory and inhibitory nature of the neuron input and determines the final orientation of the magnetization. A resistive crossbar array, functioning as synapses, generates a bipolar current that is a weighted sum of the inputs. The simulation of a two layer feed-forward artificial neural network based on the SOT electronic neuron shows that it consumes ∼3× lower power than a 45 nm digital CMOS implementation, while reaching ∼80% accuracy in the classification of 100 images of handwritten digits from the MNIST dataset.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2016

Loss mechanisms in superconducting thin film microwave resonators

We present a systematic analysis of the internal losses of superconducting coplanar waveguide microwave resonators based on niobium thin films on silicon substrates. In particular, we investigate losses introduced by Nb/Al interfaces in the center conductor, which is important for experiments where Al based Josephson junctions are integrated into Nb based circuits. We find that these interfaces can be a strong source for two-level state (TLS) losses, when the interfaces are not positioned at current nodes of the resonator. In addition to TLS losses, for resonators including Al, quasiparticle losses become relevant above 200 mK. Finally, we investigate how losses generated by eddy currents in conductive material on the backside of the substrate can be minimized by using thick enough substrates or metals with high conductivity on the substrate backside.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2016

Analysis of the processes occurring in a submicrosecond discharge with a linear current density of up to 3 MA/cm through a thick-wall stainless-steel electrode

The state of conductors carrying a megampere current from the generator to the load is studied experimentally. It is found that the plasma produced from cylindrical stainless-steel tubes during the passage of a submicrosecond current pulse with a linear density of 3 MA/cm expands with a velocity of 5.5 km/s. Numerical results on the diffusion of the magnetic field induced by a current with a linear density of 1–3MA/cm into metal electrodes agree with the experimental data on the penetration time of the magnetic field. For a linear current density of 3.1 MA/cm, the experimentally determined electric field strength on the inner surface of the tube is 4 kV/cm. The calculated electric field strength on the inner surface of the tube turns out to be two times higher, which can be explained by plasma production on the outer and inner surfaces of the electrode.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

NASA NTRS1995

A quality monitor and monitoring technique employing optically stimulated electron emission

A light source directs ultraviolet light onto a test surface and a detector detects a current of photoelectrons generated by the light. The detector includes a collector which is positively biased with respect to the test surface. Quality is indicated based on the photoelectron current. The collector is then negatively biased to replace charges removed by the measurement of a nonconducting substrate to permit subsequent measurements. Also, the intensity of the ultraviolet light at a particular wavelength is monitored and the voltage of the light source varied to maintain the light a constant desired intensity. The light source is also cooled via a gas circulation system. If the test surface is an insulator, the surface is bombarded with ultraviolet light in the presence of an electron field to remove the majority of negative charges from the surface. The test surface is then exposed to an ion field until it possesses no net charge. The technique described above is then performed to assess quality.

Yost, William T.↗