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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Biomaterial–Based Solid–Electrolyte Organic Electrochemical Transistors for Electronic and Neuromorphic Applications

In this work a systematic study of biomaterial–based solid–state organic electrochemical transistors (OECTs) is presented in which biogels consisting of gelatin and glycerol, two food–grade materials, are chosen as the model solid electrolyte. Such gels are fundamentally attractive for bioelectronics and wearable applications due to their superior and tunable electrical and mechanical properties, which allow one to fabricate solid–state organic transistors with high ON/OFF ratio and transconductance, possible millisecond–switching speed, and 6–month stability in ambient air. Next, the authors show a good control of the state–retention property of biogel OECTs, demonstrated herein by employing them as artificial synapses with various synaptic functions, such as frequency–based short–term plasticity. This study herein paves the way for the development of biomaterial–based electronics by providing guiding principles for future works that employ biomaterials in OECTs.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Microstructure Characterization of Fiber Laser Welds of S690QL High-Strength Steels

The use of fiber laser welding to join S690QL steels has attracted interest in the field of construction and assembly. Herein, 13-mm-thick S690QL welded joints were obtained without filler materials using the fiber laser. The as-welded microstructures and the impact energies of the joints were characterized and measured using electron microscopy in conjunction with high-resolution transmission electron images, X-ray diffraction, and impact tests. The results indicated that a single-sided welding technique could be used to join S690QL steels up to a thickness of 12 mm (fail to fuse the joint in the root) when the laser power is equal to 12 kW (scan speed 1 m/min). Double-side welding technique allows better weld penetration and better control of heat distribution. Observation of the samples showed that the fusion zone exhibited bainitic and martensitic microstructures with increased amounts of martensites (Ms) compared with the base materials. Also, the grains in the fusion zone increased in coarseness as the heat input was increased. The fusion zone exhibited increased hardness (397 HV{sub 0.2}) while exhibiting a simultaneous decrease in the impact toughness. The maximum impact energy value of 26 J was obtained from the single-side-welded sample, which is greater than those obtained from the double-side-welded samples (maximum of 18 J). Many more dislocations and plastic deformations were found in the fusion zone than the heat-affected zone in the joint, which hardened the joints and lowered the impact toughness. The microstructures characterized by FTEM–energy-dispersive X-ray spectrometer also exhibited laths of M, as well as stacking faults and dislocations featuring high-density, interfacial structure ledges that occur between the high-angle grain boundaries and the M and bainite.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Shape-directed rotation of homogeneous micromotors via catalytic self-electrophoresis

The pursuit of chemically-powered colloidal machines requires individual components that perform different motions within a common environment. Such motions can be tailored by controlling the shape and/or composition of catalytic microparticles; however, the ability to design particle motions remains limited by incomplete understanding of the relevant propulsion mechanism(s). Here, we demonstrate that platinum microparticles move spontaneously in solutions of hydrogen peroxide and that their motions can be rationally designed by controlling particle shape. Nanofabricated particles with n-fold rotational symmetry rotate steadily with speed and direction specified by the type and extent of shape asymmetry. The observed relationships between particle shape and motion provide evidence for a self-electrophoretic propulsion mechanism, whereby anodic oxidation and cathodic reduction occur at different rates at different locations on the particle surface. We develop a mathematical model that explains how particle shape impacts the relevant electrocatalytic reactions and the resulting electrokinetic flows that drive particle motion.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Antiferromagnetic metal phase in an electron-doped rare-earth nickelate

Long viewed as passive elements, antiferromagnetic materials have emerged as promising candidates for spintronic devices due to their insensitivity to external fields and potential for high-speed switching. Recent work exploiting spin and orbital effects has identified ways to electrically control and probe the spins in metallic antiferromagnets, especially in non-collinear or non-centrosymmetric spin structures. The rare-earth nickelate NdNiO 3 is known to be a non-collinear antiferromagnet in which the onset of antiferromagnetic ordering is concomitant with a transition to an insulating state. In this work, we find that for low electron doping, the magnetic order on the nickel site is preserved, whereas electronically, a new metallic phase is induced. We show that this metallic phase has a Fermi surface that is mostly gapped by an electronic reconstruction driven by bond disproportionation. Furthermore, we demonstrate the ability to write to and read from the spin structure via a large zero-field planar Hall effect. Our results expand the already rich phase diagram of rare-earth nickelates and may enable spintronics applications in this family of correlated oxides.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Solar wind density spectra around the ion spectral break

This paper presents a large statistical analysis of ≈5800 frequency spectra of the solar wind density fluctuations in the range 0.001–5 Hz (corresponding to spatial scales of 100–5 × 10{sup 5} km). The analysis confirms that the spectrum consists of three segments divided by two breakpoints and that each of the segments can be described by a power-law function with a spectral index α. The first segment corresponds to MHD scales and is followed by a plateau, and the third segment can be associated with the kinetic range. The statistics show that the values of the spectral slopes depend on the density fluctuations; their increasing amplitude leads to a steepening of each segment. The index of −1.8 can typically be found at MHD scales and averaging of the spectra in the frequency domain leads to an index of −8/3 at kinetic scales, whereas averaging in frequencies normalized to the ion gyrostructure frequency, f{sub g}, defined as the ratio of the solar wind bulk speed and thermal ion gyroradius, provides a value of −7/3. Both breakpoint locations are controlled by the gyrostructure frequency.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Multi-amplifier Sensing Charge-coupled Devices for Next Generation Spectroscopy

We present characterization results and performance of a prototype Multiple-Amplifier Sensing (MAS) silicon charge-coupled device (CCD) sensor with 16 channels potentially suitable for faint object astronomical spectroscopy and low-signal, photon-limited imaging. The MAS CCD is designed to reach sub-electron readout noise by repeatedly measuring charge through a line of amplifiers during the serial transfer shifts. Using synchronized readout electronics based on the Dark Energy Spectroscopic Instrument CCD controller, we report a read noise of 1.03 e$^{−}$ rms pix$^{−1}$ at a speed of 26 μs pix$^{−1}$ with a single-sample readout scheme where charge in a pixel is measured only once for each output stage. At these operating parameters, we find the amplifier-to-amplifier charge transfer efficiency (ACTE) to be >0.9995 at low counts for all amplifiers but one for which the ACTE is 0.997. This charge transfer efficiency falls above 50,000 electrons for the read-noise optimized voltage configuration we chose for the serial clocks and gates. The amplifier linearity across a broad dynamic range from ∼300 to 35,000 e$^{−}$ was also measured to be ±2.5%. We describe key operating parameters to optimize on these characteristics and describe the specific applications for which the MAS CCD may be a suitable detector candidate.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Computational Fluid Dynamics Simulation Study of Active Power Control in Wind Plants

This paper presents an analysis performed on a wind plant's ability to provide active power control services using a high-fidelity computational fluid dynamics-based wind plant simulator. This approach allows examination of the impact on wind turbine wake interactions within a wind plant on performance of the wind plant controller. The paper investigates several control methods for improving performance in waked conditions. One method uses wind plant wake controls, an active field of research in which wind turbine control systems are coordinated to account for their wakes, to improve the overall performance. Results demonstrate the challenge of providing active power control in waked conditions but also the potential methods for improving this performance.

17 WIND ENERGY↗
DOE OSTI2019

A Megawatt-Scale Medium-Voltage High-Efficiency High Power Density “SiC+Si” Hybrid Three-Level ANPC Inverter for Aircraft Hybrid-Electric Propulsion Systems

A hybrid-electric propulsion system is an enabling technology to make the aircraft more fuel saving, quieter, and lower carbide emission. In this article, a megawatt (MW) scale power inverter based on a three-level active neutral-point-clamped (3L-ANPC) topology will be developed. To achieve high efficiency, the switching devices operating at carrier frequency in the power converter are configured by the emerging silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors, while the conventional silicon (Si) insulated-gate bipolar transistors are selected for switches operating at the fundamental output frequency. To obtain high power density, dc bus voltage is increased from the conventional 270 V to medium voltage of 2.4 kV to reduce cable weight. Also, unlike the traditional 400 Hz dominated aircraft ac systems, the rated fundamental output frequency here is boosted to 1.4 kHz to drive the high-speed motor, which helps further to reduce the motor weight. Main hardware development and control modulation strategies are presented. Experimental findings are presented to verify the performance of this MW-scale medium-voltage “SiC+Si” hybrid 3L-ANPC inverter. It is shown that the 1-MW 3L-ANPC inverter can achieve a high efficiency of 99% and a high power density of 12 kVA/kg.

42 ENGINEERING↗
DOE OSTI2019

CEBAF Photo Gun RF System

During the CEBAF 12 GeV Upgrade at Jefferson Lab, a fourth experimental hall, ?D?, was added to the existing three halls. To produce four beams and deliver them to all halls concurrently requires new frequencies and a new timing pattern of the electron bunches. Since a photo-gun is used to produce electron bunches, the gun?s drive laser pulses need to be synchronized with the required bunch rate frequencies of 499 MHz or 249.5 MHz. To meet these new operational requirements, the new LLRF system has been proposed. Very specific requirements (dual frequency operation) on one side and the simple RF drive mode operation on the other imply the use of a commercial off-the-shelf digital platform rather than a system typical for RF cavity field control. We have chosen the Texas Instruments FPGA board along with a high-speed 8-Channel, 14-Bit board, and a 4-Channel, 16-Bit board. The DAC board includes the clock generator for clocking ADCs, DACs and the FPGA. The only custom design section of the system is the RF Front End board. The complete Gun Laser LLRF system has been designed, built, and recently commissioned in the CEBAF Injector. This paper will detail the design and report on commissioning activities.

Plawski, Tomasz↗
DOE OSTI2020

Basic Research Needs for Transformative Manufacturing (Brochure)

Manufacturing is central to the nation’s prosperity and security. Manufacturing currently represents about 12% of the gross domestic product, provides nearly 13 million jobs, and accounts for about 25% of energy use. The nation’s economy relies heavily on wide-ranging manufacturing sectors - all of which share common challenges including data issues, lack of physics and chemistry-based models across scales, and resource constraints in a global environment. Furthermore, there are many hurdles that must be overcome to move basic science innovations to market. Addressing broad-ranging challenges demands a basic-science strategy that underpins applied research activities. This strategy would accelerate innovation and transform manufacturing. A Basic Research Needs workshop for Transformative Manufacturing was held in March 2020. The focus of the workshop was to identify the basic science research priorities that could accelerate innovation to transform manufacturing in the future. This was the first workshop of its kind to examine how basic energy science can drive manufacturing forward and innovate new ways to manufacture goods. Five Priority Research Directions were identified that address these science challenges: (1) innovative synthetic approaches to enable scalable assembly of matter, (2) computational methods and theoretical models to transform how manufacturing processes are controlled, (3) new characterization tools that can handle the necessary complexity, scales, and processing speeds to meet manufacturing needs, (4) new science to address opportunities relevant to sustainable and energy-efficient manufacturing, and (5) foundational approaches to co-design of materials, process, and products.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Basic Research Needs for Transformative Manufacturing

This report is based on a Basic Research Needs workshop for Transformative Manufacturing, which was held March 9 - 11, 2020. The focus of the workshop was to identify the basic science research priorities that could accelerate innovation to transform manufacturing in the future. This was the first workshop of its kind to examine how basic energy science can drive manufacturing forward and innovate new ways to manufacture goods. Five Priority Research Directions were identified that address these science challenges: (1) innovative synthetic approaches to enable scalable assembly of matter, (2) computational methods and theoretical models to transform how manufacturing processes are controlled, (3) new characterization tools that can handle the necessary complexity, scales, and processing speeds to meet manufacturing needs, (4) new science to address opportunities relevant to sustainable and energy efficient manufacturing, and (5) foundational approaches to co-design of materials, process, and products.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Keyless Infrastructure Security Solution (KISS) (Technology Landscape Analysis Report)

The following landscape analysis explores blockchain or distributed ledger technologies application to securing electricity infrastructure. The exploration of how distributed ledger technologies can be used to increase the trustworthiness and integrity of the grid’s edge is imperative to the economic, security and well-being of all modern societies that rely on electricity. Blockchain technology’s ability to secure, track and optimize complex data transactions provides an exciting value proposition to securing and optimizing the U.S. power grid. An energy delivery system (EDS) operating at the grid’s edge requires unprecedented levels of security and trustworthiness to verify integrity of data and manage complex transactive and distributed Energy Resources (DERs) exchanges. Moreover, grid-edge devices lack visibility, control and security to conduct real-time energy transactions with the required security, speed and scale. The U.S. power grid is a complex system of systems that requires secure, reliable and trustworthy EDSs. Grid modernization has increased the speed and size of data sets exchanged on these systems (Gordes and Mylrea 2014). Exasperating the challenge is these systems are increasingly distributed creating new data fidelity and interoperability challenges for grid operators struggling to balance and incorporate DERs. Blockchain technology provides an atomically verifiable cryptographic signature to help increase the trustworthiness of EDSs at the grid’s edge. This feature is especially important at distribution level since EDSs and field devices have increasing operational and security requirements that are often diametrically opposed. For example, as data, speed and analytic requirements increase, security and functionality requirements increase. Further, as the grid’s edge incorporate DERs and transacts in real time, availability is prioritized over the integrity and confidentially of that data. Blockchain presents the prospect of solving some of these complex challenges related to grid security and modernization. However, there are more questions about blockchain applicability than answers. There are number of theoretical blockchain applications to the energy sector, but few energy utilities have actually applied, implemented or even experimented with the underlying distributed ledger technology and consensus algorithms that enable blockchain to exchange data more efficiently and securely.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2023

Hypervelocity impact in stellar media: heat shielding, shock fronts and ablation clouds

The Frontier Plasma Science experiments proposed by our team will model the processes occurring during spacecraft atmospheric entries and meteorite planetary collisions by inserting material targets into the Scrape off Layer (SOL) and edge plasma of a tokamak. This project will investigate important plasma-material processes during high-enthalpy atmospheric entries, including heat flux generation and material ablation. Of particular interest is to explore heat and particle flux detachment in front of the sample using concepts and techniques developed in the latest studies of divertor detachment. Exploration missions to the Solar System’s gaseous giants and hyperbolic re-entries into the Earth’s atmosphere require spacecraft that can withstand high velocity (>10 km/s), high heat fluxes (>10 MW/m2), and corresponding enthalpies. Ablative materials have been used as thermal shields to protect the spacecraft from severe heating during entry. However, developing high enthalpy ablating materials is challenging due to the lack of adequate ground testing facilities. Our team stated that the performance of candidate shielding materials could be assessed in a laboratory environment with multiple in-situ diagnostics, which was enabled by the progress in the tokamak research. Modern machines feature relatively long discharges (~10 s) with well-controlled stable plasma conditions at the edge where the heat flux and the flow speed are similar to those experienced during atmospheric entries. The experiments were carried out at the DIII-D National Fusion Facility in San Diego, CA, operated by General Atomics (GA) for the DoE.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

SpinQuest Polarized Target System

The SpinQuest experiment at Fermilab uses a solid-state polarized ammonia target held at a magnetic field of 5 T, immersed in liquid helium-4, which is held at approximately 1K by the evaporation refrigerator. The refrigerator provides the required cooling power during the dynamic nuclear polarization (DNP) process and the high intensity interaction with the 120 GeV proton beam from the Fermilab main injector. The refrigerator was designed in compliance with the American Society of Mechanical Engineers (ASME) to operate safely at Fermilab. The high pumping capacity ($17,000 \:m^3/h$) roots stack provides the required pumping speed during DNP production data taking and a custom-made radiation hard flow control valve regulates the refrigerator temperature during the thermal equilibrium calibration measurements. The frequency of the microwave generator, an Extended Interaction Oscillator (EIO), is automated to keep the maximum polarization while the (Nuclear Magnetic Resonance) NMR system continuously measures the polarization of the target material. In this talk, an overview of the SpinQuest polarized target system will be presented as well as a brief report of recent commissioning activities and target performance during the early production runs in 2024.

Bandara, Vibodha [Colombo U.]↗
DOE OSTI2025

Large-eddy simulation of an atmospheric bore and associated gravity wave effects on wind farm performance in the southern Great Plains

Gravity waves are a common occurrence in the atmosphere, with a variety of generation mechanisms. Their impact on wind farms has only recently gained attention, with most studies focused on wind farm-induced gravity waves. In this study, the interaction between a wind farm and gravity waves generated by an atmospheric bore event is assessed using multiscale large-eddy simulations. The atmospheric bore is created by a thunderstorm downdraft from a nocturnal mesoscale convective system (MCS). The associated gravity waves impact the wind resource and power production at a nearby wind farm during the American Wake Experiment (AWAKEN) in the US southern Great Plains. A two-domain nested setup (Δx=300 and 20 m) is used in the Weather Research and Forecasting (WRF) model, forced with data from the High-Resolution Rapid Refresh model, to capture both the formation of the bore and its interaction with individual wind turbines. The MCS is resolved on the large outer domain, where the structure of the bore and the associated gravity waves are found to be especially sensitive to parameterized microphysics processes. On the finer inner domain, gravity wave interactions with individual wind turbines are resolved; wake dynamics are captured using a generalized actuator disk parameterization in WRF. The gravity waves are found to have a strong effect on the atmosphere above the wind farm; however, the effect of the waves is more nuanced closer to the surface where there is additional turbulence, both ambient and wake-generated. Notably, the gravity waves modulate the mesoscale environment by weakening and dissipating the preexisting low-level jet, which reduces hub-height wind speed and hence the simulated power output, which is confirmed by the observed supervisory control and data acquisition (SCADA) power data. Additionally, the gravity waves induce local wind direction variations correlated with fluctuations in pressure, which lead to fluctuations in the simulated power output as various turbines within the farm are subjected to waking from nearby turbines.

17 WIND ENERGY↗
DOE OSTI2020

AI-Science for Performance Optimization and Diagnosis of Science Instrument Federations

Next generation of science workflows are expected to be executed over complex federations composed of supercomputers, science instruments, storage systems and networks, with new additions of the edge and cloud systems and services. The sheer complexity of these multi-domain federations makes it hard to manage them and optimize their performance, as small impedance mismatches (that can dynamically develop between systems) could drastically degrade the entire federation performance. Recent proliferation of Software Defined Everything (SDX) technologies combined with containerization frameworks provide custom instruments that can monitor and collect critical measurements at various levels to support diagnoses and performance optimization; but their data too enormous for human operators and analysts to process and generate decisions. Machine Learning (ML) methods that extract critical parameters, relationships and trends from the data offer general solutions. Artificial Intelligence (AI) and ML methods must be custom-developed for these problems based on solid, rigorous foundations, since black-box approaches are often ineffective and unsound.We propose to develop comprehensive AI-Science for the performance of science federations to (i) monitor and control storage, networks, experiments, and computing systems across multiple domains via softwarization layers, at speeds and scales orders of magnitude superior to current practice, (ii) optimally realize and orchestrate complex workflows with high performance by using dynamic state and performance estimation methods, and (iii) aggregate measurements across sites and time to develop infrastructure-level profiles, optimizations and diagnoses using AI-Science based on foundational principles from ML, game theory, and information fusion areas.

Rao, Nageswara↗
DOE OSTI2021

Reachability Analysis for FollowerStopper: Safety Analysis and Experimental Results

Motivated by earlier work and the developer of a new algorithm, the FollowerStopper, this article uses reachability analysis to verify the safety of the FollowerStopper algorithm, which is a controller designed for dampening stop-and-go traffic waves. With more than 1100 miles of driving data collected by our physical platform, we validate our analysis results by comparing it to human driving behaviors. The FollowerStopper controller has been demonstrated to dampen stop-and-go traffic waves at low speed, but previous analysis on its relative safety has been limited to upper and lower bounds of acceleration. To expand upon previous analysis, reachability analysis is used to investigate the safety at the speeds it was originally tested and also at higher speeds. Two formulations of safety analysis with different criteria are shown: distance-based and time headway-based. The FollowerStopper is considered safe with distance-based criterion. However, simulation results demonstrate that the FollowerStopper is not representative of human drivers - it follows too closely behind vehicles, specifically at a distance human would deem as unsafe. On the other hand, under the time headway-based safety analysis, the FollowerStopper is not considered safe anymore. A modified FollowerStopper is proposed to satisfy time-based safety criterion. Simulation results of the proposed FollowerStopper shows that its response represents human driver behavior better.

Chou, Fang-Chieh↗
DOE OSTI2023

Modeling Advanced Strippers for CO2 Capture from Gas-Fired Power Plants using Aqueous Piperazine

Energy performance of 5 m piperazine was evaluated with an advanced stripper at the pilot scale, accounting for heat loss. Modeling studies indicated that heat loss at locations other than the heat source impacted the heat duty. For strippers with excess packing, the column was the most important source of heat loss, and values as low as 0.03 GJ/hr can cause pinch and reabsorption of CO2. Solvents like 5 m PZ are more affected by heat loss in the column due to a top-side temperature pinch at high lean loading. Heat loss impacts NGCC CO2 capture more than coal-based CO2 capture. Surface temperature measurements pilot plants showed that heat loss was 50-75% controlled by natural convection. Measured heat loss was correlated with steam flowrate and wind speed and ranged from 8126 to 219668 Btu/hr, representing 35% of the measured heat rate on average. Net heat duty linearly varied with CO2 removal at low lean loading and was similar for coal and NGCC conditions at fixed removal. At 90% removal, net heat duty was about 2.5 GJ/t with 4 and 12% CO2 in the flue gas. 7 At NGCC conditions, strippers with finite packing can benefit from a flashing feed to the top of the column by using a hot bypass. A flashing feed was linked to a reduction in irreversibility of the stripper from temperature driving forces. It also reduces heat duty by up to 6% at fixed packing height and reduces packing requirement for a fixed steam heater size compared to a warm bypass. Lean loading and lean solvent rate were effective handles to maximize profitability of a fixed stripper design at low gas price. High ambient temperature operation can benefit from low pressure stripping to about 0.18 lean loading at 150 ℃ to maintain the cyclic capacity at reduced rich loading. At low gas price, the capture plant was able to maximize profitability even with a high heat duty of 2.7-3.1 GJ/t at a lean loading of 0.2-0.22 mol/mol. Heat recovery by partial water vapor condensation in a gas-liquid exchanger can be replaced by a direct contact condenser (DCC). The DCC improved gas cooling and reduced heat duty compared to the CO2 exchanger at 0.2 lean loading. The DCC when used with a 150 ℃/5.5 bar stripper can reduce the cost of capture compared to the base case by $3- 4/tonne at 15 ft of packing (optimum) but increases cost of capture by $6/tonne with a 120 ℃/2 bar stripper and 10 ft of packing (optimum). The DCC can work effectively with a solvent with a high heat of absorption and thermal stability.

Suresh Babu, Athreya↗