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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 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Impedance Scan of Inverter-Based Resources and Diesel Generator for Stability Analysis

Impedance-based methods are widely used for power system stability analysis with inverter-based resources (IBRs), e.g., assessing dynamic interactions between the power grid and an IBR, control interactions between multiple IBRs, and the sub-synchronous oscillation and damping phenomenon. Since it is difficult to get a numerical model 100% matching with the hardware IBR, using the hardware inverter directly to obtain its output impedance has become a prominent approach nowadays. Therefore, this article presents the impedance scan using hardware IBRs, and also a hardware diesel generator as it still stays with the grid before the grid completely goes to renewable. The devices under test (DuTs) for the impedance scan includes two 3-..phi.., 480 V, 60 Hz commercial grid-forming IBRs (one of 250 kVA and another of 125 kVA rating) in series with ..delta..-Y transformers, one 3-..phi.., 480 V, 60 Hz commercial grid-following IBR (of 125 kVA rating), and a 3-..phi.., 480 V, 60 Hz commercial diesel generator (of 187.5 kVA rating). Using voltage signals perturbed with sub-, inter-, and higher harmonic components, and measuring the current response, the positive-sequence impedances are computed via an offline-based post-analysis. Moreover, best-fit transfer functions are estimated that closely resemble the measured data points of the positive-sequence impedances. Based on the observations from various outcomes of the hardware experiments, this article also provides some fundamental insights on the equivalent positive-sequence impedance of a combination of multiple hardware components by comparing the estimated and the empirically computed impedances. A comparative insight on the damping capability of the DuTs using the positive-sequence impedances of the hardware is also discussed.

current measurement↗
DOE OSTI2011

System for Spectral Characterization of Solar Cell Structures

The spectral characterization system presented in this work is one based on a monochromator and it is able to deliver an under - millimeter spot size. The system is fully controlled by computer, shows good repeatability and high accuracy in spectral characterization of photovoltaic devices by the determination of internal quantum efficiency over an extended wavelength range. Two solutions for extended range detectors are explored in this study: pyroelectric and sandwich detectors. Most of the results shown in this abstract were obtained using a pyroelectric detector. The full version of the paper will show a comparison between the two types of detectors. Scanning images (maps) of internal quantum efficiency (IQE) and of external quantum efficiency (QE) can be obtained with high spatial resolution both in AC and DC mode. I-V curves can be obtained in monochromatic or white light in the same location as the IQE curves without a supplemental repositioning. Because IQE curves and I-V curves are obtained in the same location and using the same optics, a full characterization of the photovoltaic device under test is possible in a single run.

14 SOLAR ENERGY↗
DOE OSTI2011

A Pneumatic Actuated Microfluidic Beads-Trapping Device

The development of a polydimethylsiloxane (PDMS) microfluidic microbeads trapping device is reported in this paper. Besides fluid channels, the proposed device includes a pneumatic control chamber and a beads-trapping chamber with a filter array structure. The pneumatic flow control chamber and the beads-trapping chamber are vertically stacked and separated by a thin membrane. By adjusting the pressure in the pneumatic control chamber, the membrane can either be pushed against the filter array to set the device in trapping mode or be released to set the device in releasing mode. In this paper, a computational fluid dynamics simulation was conducted to optimize the geometry design of the filter array structure; the device fabrication was also carried out. The prototype device was tested and the preliminary experimental results showed that it can be used as a beads-trapping unit for various biochemistry and analytical chemistry applications, especially for flow injection analysis systems.

42 ENGINEERING↗
DOE OSTI2017

Optimization of sensors based on surface waves in flat-layered structures

A method for increasing the sensitivity of surface-wave sensors in multifilm structures is proposed based on the results of a theoretical study of the reflection of a plane electromagnetic wave from a flat-layered structure containing homogeneous films. A method for optimizing the parameters of the films forming the surface structure is developed and tested. The devices proposed are characterized by high field amplification in a surface layer of multifilm structure and a higher sensitivity to variations in the optical properties of the thin near-surface layer. Application of the proposed multifilm structures is expected to increase significantly the sensitivity of the existing sensors based on surface-plasmon polaritons, which are applied in modern optical multichannel biological, chemical, and physical sensor systems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Verilator Testbench Environment (VTE) v0.1

VTE is a library that allows fast and simple generation of C++ testers for modules written in Chisel and build an efficient interface to existing C++ based simulators. It contains Scala-based interface and C++ testbench class. Scala interface interacts with Firtl Interpreter and generates a basic set of C++ testbench files. These files contain the list of the Device Under Test (DUT) input-output ports as well as their parameters. C++ testbench provides functionalities similar to the Chisel PeekPokeTester, such as poke, expect, step functions. As a backend it uses Verilator.

Fatollahi-Fard, Farzad↗
DOE OSTI2021

System Validation Platform Working Directories

A suite of software tools used to interface with power electronic equipment for laboratory testing and device certification. They are typically used as equipment drivers with using the System Validation Platform (SVP) graphical user interface (GUI). Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2021-1185 O

Johnson, JayT↗
DOE OSTI2014

Reference Model 2 Scaled Geometry (RM2: River Current Turbine)

Contains the Reference Model 2 (RM2) scaled scale geometry files of the River Current Turbine, developed by the Reference Model Project (RMP). These scaled geometry files are saved as SolidWorks assembly, IGS, and STEP files, and require a CAD program to view. The scaled RM2 device was tested at the Saint Anthony Falls Laboratory (SAFL) at the University of Minnesota flume. The scale of the geometries included in this submission are at a 1:15 scale compared to the full scale geometry. 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 2 (RM2) is a variable speed dual-rotor cross-flow river turbine that is deployed at the water?s surface. It was designed for deployment at a reference site modeled after a reach in the Mississippi River near Baton Rouge, Louisiana. The rotors are anchored to a two-pontoon vessel platform. Surface deployment of the turbine minimizes the handling requirements during deployment and recovery and reduces overall costs for all O&M activities, including allowing for easy access to the power conversion chain (PCC). The design (two rotors per platform) also reduces the environmental footprint and associated environmental compliance costs.

16 TIDAL AND WAVE POWER↗
DOE OSTI2026

Evaluation of a Smoke Opacity Sensor for Improving Residential Wood Heater Combustion

Residential wood heating lacks real-time particulate matter (PM) monitoring technologies capable of measuring emissions directly from flue gases. This study evaluates the performance of the Octoring, an opacity-based smoke sensor developed to monitor wood heater emissions and provide feedback for improved combustion. The device was tested on catalytic and non-catalytic cordwood heaters and a pellet heater during startup, high-burn, and low-burn phases. Performance was assessed against reference particle instruments and gravimetric measurements using concordance, correlation, and agreement analyses. Results show that temperature-dependent drift is the primary limitation affecting sensor accuracy, with systematic drift observed across ambient and combustion conditions. Agreement with reference instruments ranged from poor to good depending on operating conditions, with the strongest performance observed during pellet heater high-burn operation. These findings establish a performance baseline for opacity-based sensing technologies and identify key areas for further development before practical deployment in residential wood combustion monitoring systems.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Loads as a Resource: Frequency Responsive Demand

Frequency control plays an important role in preserving the power balance of a multi-machine power system. Generators modify their power output when a non-zero frequency deviation is presented in order to restore power balance across the network. However, with plans for large-scale penetration of renewable energy resources, performing primary frequency control using only supply-side resources becomes not only prohibitively expensive, but also technically difficult. Frequency control from the demand side or load control presents a novel and viable way for providing the desired frequency response. Loads can measure frequency locally and change their power consumption after a non-zero frequency deviation is presented in order to achieve power balance between generation and consumption. The specific objectives of this project are to: •Provide a framework to facilitate large-scale deployment of frequency responsive end-use devices •Systematically design decentralized frequency-based load control strategies for enhanced stability performance •Ensure applicability over wide range of operating conditions while accounting for unpredictable end-use behavior and physical device constraints •Test and validate control strategy using large-scale simulations and field demonstrations •Create a level-playing field for smart grid assets with conventional generators

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2018

Nuclear Power Plant Component Flooding Fragility Research

This report describes progress on Nuclear Power Plant component flooding fragility research conducted at the Component Flooding Evaluation Laboratory (CFEL). The progress includes additional steering committee membership and invitations, performance improvements to the Portal Evaluation Tank (PET), PET based experiments using industrial steel doors, pipe rupture spray pattern characterization, coupling the smoothed particle hydrodynamics (SPH) code Neutrino and the Idaho National Laboratory (INL) developed Risk Analysis Virtual Environment (RAVEN), continued development of component fragility mathematical models, and wave impact simulation device development, testing, and analysis.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2018

Light Extraction System for OLED (LESO)

The DOE Office of Energy Efficiency and Renewable Energy is funding development of Solid-State Lighting (SSL) to replace incandescent and fluorescent technologies. A more aggressive innovation schedule could achieve site electricity consumption reductions from current projections of 40% to 60% by the year 2030 when compared to the no-LED scenario in the United States. These increased reductions would total an increase in savings of 395 TWh of energy. Based on preliminary data showing improvements of 2x in extraction efficiency with diffuser films, we will optimize surface relief structures to maximize the light extraction efficiency of OLED devices and test the optimized structures in prototype samples. To address the DOE desire for rapid SSL acceptance, Luminit, LLC, proposes to develop a new Light Extraction System for OLED (LESO) implemented in an ultraviolet (UV)-curable HRI polymer. The LESO uses optimized surface relief structures in high-index and low-index interfaces, which will significantly increase light extraction from the OLEDs. The LESO will significantly reduce environmental pollution compared to incandescent, compact fluorescent (CFL), and LED lamps. It will do so at a low price compared to other technologies, and with extremely high quality lighting (nearly perfect color matching, for example). Through LESO adoption, both CO 2 and other pollutants will be reduced by hundreds of megatons annually.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

High Precision Integrated Beam-Position and Emittance Monitor

The purpose of this project was to design and build a set of resonant cavity beam diagnostics including a monopole cavity, two dipole cavities, and a quadrupole mode cavity. An array of such diagnostics placed in an accelerator FODO lattice can be used to reconstruct beam emittance and envelope information on a pulse-by-pulse basis. In this project a more efficient quadrupole cavity shape was discovered which could provide the required sensitivity with just two cells vs. nine cells as originally envisioned. This new design was studied and optimized with RF simulation programs, followed by mechanical specifications and drawings, and fabrication of the diagnostics. The device was tested with a relativistic electron beam at Brookhaven National Laboratory ATF accelerator.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Advanced Thermal Management for High Power Density Electronics

Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm x 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25°C air temperature, 20-45% relative humidity) to determine the effects of gap spacing (2-4 mm), electric field (50-250 V/cm), and heat flux (demonstrated to 13 W/cm 2 ). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈ 200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm 2 . This work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.

42 ENGINEERING↗
DOE OSTI2019

High Voltage Modeling and Testing of Transformer, Line Interface Devices, and Bulk System Components Under Electromagnetic Pulse, Geomagnetic Disturbance, and other Abnormal Transients

This project aims at quantitatively analyzing possible knowledge gaps related to the risk of Electromagnetic Pulse (EMP) impact on high-voltage, power transformers (transmission-class), that represent the most critical power grid assets. In relation to the electric infrastructure, some past studies indicate that the grid is overall fairly robust and resilient against most EMP threats. This assessment stems, in part, from estimates of the peak voltage that can be induced on a transmission power line for a nominal EMP fast-transient, compared with the typically very high basic insulation level that is featured by the high-voltage infrastructure. The project provides additional insight toward a more comprehensive risk evaluation of the grid EMP and Geomagnetic Disturbances (GMD) vulnerabilities. This work is aligned with the U.S. Dept. of Energy current research thrust in support of the development of a highly secure and resilient power infrastructure. Project milestones have been devised to address the fundamental technical issues in support of protection of large power transformer against EMP threats. More specifically, this project included parallel research tasks focused on the following topics: analysis of EMP-induced, fast-transient, current and voltages on a variety of power line configurations and EMP impact scenarios, detailed characterization of EMP damage potential due to the voltage surge, from the impact on the power line, to the transformer windings, GMD and EMP slow transients and impact from harmonics generation and reactive power flow on a complex grid layout, and identification of risk mitigation paths, with emphasis on GIC damage prevention for large power transformers, and on impact protection options from a grid stability perspective.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2019

Sandia National Laboratories (FY19 Progress Report)

The Energetic Neutrons campaign led by Sandia National Laboratories (SNL) had a successful year testing electronic devices under 14 MeV neutron irradiation at OMEGA. During FY19 SNL employees were trained to take over new responsibilities while visiting LLE, continued collaborating with external organizations and generated knowledge that supports SNL's National Security mission.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

PSL-AC-CP-1102-004-03: Electrostatic Discharge Simulator Kit Model 930D and Associated Current-Viewing Resistor (V.04)

This document provides instructions for calibrating the Electro-Tech (ETS) electrostatic discharge (ESD) simulator, Model 930D. The calibration shall meet the ± 5% specification for resistance and capacitance as specified in MIL-STD-331C 2009 newer. A series of direct measurements of the Device Under Test (DUT) output at 25 kV using a calibrated LeCroy HDO 6104 oscilloscope (or equivalent 1 MΩ) input impedance storage oscilloscope) are recorded through the 500-pF capacitor, 500-Ω resistor, and a 1-Ω Current Viewing Resistor (CVR). The certified value of the DUT's 25 kV output is calculated using Ohms Law and the certified system resistance and capacitance described in this procedure. Read this document in its entirety before proceeding with the calibration.

42 ENGINEERING↗
DOE OSTI2021

Small-Scale Engineered High Flexibility Gasifier

This project advances a small-scale gasification unit as the first step in syngas-based hydrogen, chemicals, and synthetic fuels production. This unit is associated with an enhanced flexibility to different carbonaceous feedstocks including different types of coals, biomass, and plastics. The purpose of the project was to demonstrate feasibility and efficiency of coal pyrolysis in an auger reactor (pyrolyzer); supplemental methane and pyrolysis gas conversion into syngas in a proprietary non-catalytic converter; combined performance of pyrolyzer and non-catalytic converter to convert coal into syngas The proposed technology is based on an application of an intermediate speed pyrolysis at the temperature range 400-600°C as the first stage of biomass processing. At an industrial scale, an incorporation of coal pyrolysis into a feeding machine – auger-reactor allows to decrease its capital cost. At a pilot scale, it permits to employ electricity to build a compact device for testing of downstream equipment. The auger-reactor (pyrolyzer) generates pyrolysis gas and char practically from any carbonaceous feedstocks but their compositions and quantities are determined by their types. Pyrolysis gas is converted into syngas (mix of H 2 and CO) in a novel, proprietary hydrogen flame assisted non-catalytic converter which employs O 2 instead of air as an oxidizer. This reactor (converter) allows an easy adjustment to different pyrolysis gas compositions and tolerates a presence of sulfur and nitrogen contaminants. Our technology assumes carbonaceous feedstocks gasification with oxygen to allow the products H 2 , CO or CO 2 to be not diluted in N 2 and ready for the following synthesis of chemicals and fuels. Due to the same reason, it permits a more efficient CO 2 capture for its transport and storage. An implementation of our small-scale gasification process may overcome economic constrains by a flexible acceptance of coal, biomass, and plastics as well as their unsorted mixtures to make syngas for the following production of pure hydrogen, chemical and/or synthetic fuels.

42 ENGINEERING↗