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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Laterally coupled distributed feedback type-I quantum well cascade diode lasers emitting near 3.22 μm

The laterally coupled distributed feedback (LC-DFB) GaSb-based type-I quantum well cascade diode lasers using the second- and the sixth-order gratings to stabilize the output spectrum near 3.22 μm were designed and fabricated in this paper. The laser heterostructure contained three cascades. The devices were manufactured using a single dry etching step defining the ~5-μm-wide ridge with ~5-μm-wide gratings sections adjacent to the ridge sides. The grating coupling coefficients were estimated to be about 1 cm -1 . The stability of the single-frequency operation was ensured by alignment of the DFB mode to the relatively wide gain peak. The 2-mm-long second-order LC-DFB lasers generated above 10 mW of continuous-wave (CW) output power at 20°C in epi-side-up configuration and demonstrated power conversion efficiency above 2%. The sixth-order LC-DFB lasers showed lower efficiency but still generated several milliwatts of CW output power. Finally, the devices demonstrated a CW current tuning range of about 3.5 nm at the temperature of 20°C.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Novel Magnetically Fluidized Bed Reactor Development for the Looping Process: Coal to Hydrogen Production R&D

The coal to hydrogen project utilizes the iron/iron oxide looping process to produce high purity hydrogen. The input energy for the process is provided by syngas coming from gasification process of coal. The reaction pathways for this process have been studied and favorable conditions for energy efficient operation have been identified. The Magnetically Stabilized Porous Structure (MSPS) is invented. It is fabricated from iron and silica particles and its repeatable high performance has been demonstrated through many experiments under various conditions in thermogravimetric analyzer, a lab-scale reactor, and a large scale reactor. The chemical reaction kinetics for both oxidation and reduction steps has been investigated thoroughly inside MSPS as well as on the surface of very smooth iron rod. Hydrogen, CO, and syngas have been tested individually as the reducing agent in reduction step and their performance is compared. Syngas is found to be the most pragmatic reducing agent for the two-step water splitting process. The transport properties of MSPS including porosity, permeability, and effective thermal conductivity are determined based on high resolution 3D CT x-ray images obtained at Argonne National Laboratory and pore-level simulations using a lattice Boltzmann Equation (LBE)-based mesoscopic model developed during this investigation. The results of those measurements and simulations provide necessary inputs to the development of a reliable volume-averaging-based continuum model that is used to simulate the dynamics of the redox process in MSPS. Extensive efforts have been devoted to simulate the redox process in MSPS by developing a continuum model consist of various modules for conductive and radiative heat transfer, fluid flow, species transport, and reaction kinetics. Both the Lagrangian and Eulerian approaches for species transport of chemically reacting flow in porous media have been investigated and verified numerically. Both approaches lead to correct prediction of hydrogen production rates over a large range of experimental conditions in the laboratory scale reactor and the bench-scale reactor. In the economic analysis, a comparison of the hydrogen production plants using iron/iron oxide looping cycle and the conventional process has been presented. Plant configurations are developed for the iron/iron oxide looping cycle. The study suggests a higher electric power generation but a lower hydrogen production efficiency comparing with the conventional process. Additionally, it was shown that the price of H 2 obtained from our reactor can be as low as $\$$1.7/kg, which is 22% lower than the current price of the H 2 obtained from reforming plants.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

New Advanced Stable Electrolytes for High-voltage Electrochemical Energy Storage

To improve the performance, reliability, and safety of Li-ion batteries, new advanced materials need to be integrated into the cell design. Specifically, the DOE roadmap recognizes the importance in the automotive industry of the development of new electrolytes with improved electrochemical and thermal stability for advance cathodes with higher operating voltages, higher energy density, and reduced cost.

25 ENERGY STORAGE↗
DOE OSTI2023

Electrochemical Behaviors of Bilayer Oxygen Electrode for Reversible Solid Oxide Cells

Reducing the resistances of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) while retaining the stability of an oxygen electrode, even in the presence of air contaminants such as Cr, H2O and CO2, is of paramount importance to the current commercial development of intermediate-temperature reversible solid oxide cells (IT-RSOCs). In this presentation, a multifunctional, coarsening-resistant, air-contaminants-tolerant and yet ORR/OER-active oxygen electrode (OE) for IT-RSOCs is described. The testing results show that new bilayer OE exhibits a much better ORR/OER activity and stability than the single-layer benchmark LSCF-GDC OE. Remarkably, the new bilayer OE also demonstrates an exceptionally high resistance to Cr-attack, a critical issue to the development of commercial meal-interconnect loaded SOFC/SOEC stacks/systems. Theoretical analysis is also presented to understand the fundamental reasons for the improved ORR/OER activity and stability observed under real-world operating conditions.

Huang, Kevin↗
DOE OSTI2023

Adaptive Cyber-Physical Resilience for Building Control Systems

The main goal of the project is to develop an AI-based process layer cybersecurity suite for detection, isolation and mitigation of cyber-attack effects on operation of building energy management systems (BEMS). The following constituent key technologies were developed under the program towards fulfilling the program objectives: (1) developed a high fidelity BEMS testbed for generation of training data and validation of developed technologies; (2) developed a physics informed ML based attack detection and localization module (ADL) capable of detecting high impact stealthy attacks (HISA - attacks causing 30% energy utilization but no immediate visible impact otherwise) with 98% accuracy; (3) developed a methodology to determine ’representative days’ to limit the data required for training; (4) developed a virtual sensing system that can reconstruct affected sensors with 10% error for the same HISA set; (5) developed a resilient model predictive control system that can continue operation of the BEMS without jeopardizing stability for the HISA set; and (6) integrated and deployed all the constituent modules and demonstrated the efficacy of the technology in real-time in a hardware in loop simulation.

42 ENGINEERING↗
DOE OSTI2019

Cool GTL - A New Biogas Conversion Process from GTI

GTI is currently developing the Cool GTL process, to convert biogas into jet fuel. Cool GTL can be used to convert any biogas stream or high CO2 content natural gas to high quality liquid fuels. In Cool GTL we convert high CO2 feeds to synthesis gas at a 2-2.4/1 H2/CO ratio using a novel CO2/steam reforming catalyst which has high stability. The 2.0-2.4/1 H2/CO synthesis gas ratio is always achieved, for a variety of levels of feed CO2 content, by adjusting the amount of water added according to the amount of CO2 in the feed. The reformer catalyst has been tested for 500 hours and shows no deactivation. The product from the reformer then goes directly to a low temperature bubbling fluid bed Fischer Tropsch reactor with an integrated finishing hydroisomerization reactor which makes hydrocarbon liquids from the synthesis gas, With this configuration no wax is produced. The fluid bed allows excellent temperature control. Cool GTL is under development but still requires longer integrated testing. Currently Cool GTL is being developed at GTI through DOE funding in the project “Cool GTL for the Production of Jet Fuel from Biogas”. In this DOE project, our goal is to make 100 gallons of high quality jet fuel. This project will also demonstrate Cool GTL catalyst and process stability through long term, 24 hour operation. Once the DOE project is complete, we believe the Cool GTL process will be ready for larger scale commercial deployment in multiple applications.

09 BIOMASS FUELS↗
DOE OSTI2025

PID-Regulated Heating System for PIP-II Reference Line

The Proton Improvement Plan 2 (PIP-II) centers on building a new superconducting linear particle accelerator (Linac) at Fermilab. At the heart of the accelerator is the reference line. It is a critical system that defines the ideal path for the beam as it passes through magnets, RF cavities, and other beamline elements. Temperature stability is crucial for the reliable operation of RF components, such as mixers and filters. Fluctuations affect key performance parameters like conversion loss, isolation, and linearity. To mitigate any drift caused by ambient temperature changes, a heating plate assembly is utilized to maintain key components at a controlled temperature of 40 C. Utilizing an actively regulated heating system, a metal-oxide-semiconductor field-effect transistor (MOSFET) based power control circuit which provides input to a controller; forming a closed-loop system that maintains the desired setpoints with high precision.

Mosher, Alexander [U. Illinois, Chicago]↗
DOE OSTI2026

Development of a Chlorine Cathode and Anode Basket Assembly for Production of Uranium Chloride

A chlorine cathode has been developed for in situ chlorination of metals, oxides, and oxychlorides in molten chloride electrolytes that could be used to support synthesis of chloride fuel salts for molten salt reactors. The chlorine cathode is designed to electrochemically reduce chlorine gas to generate chloride ions that, when paired with a metal anode, chlorinate that metal as it is oxidized into the salt. The designed porous carbon electrode effectively distributes Cl 2 to the electrode surface and efficiently generates Clions in the molten chloride electrolyte. This report highlights recent improvements made to the electrode assembly, with a focus on operational control of the anode basket stability. Synthesis tests demonstrated the successful chlorination of uranium metal, resulting in 3.6 wt% uranium generated in the LiCl-KCl base salt in 45 minutes, performed in a bench-scale chlorination apparatus. Higher concentrations could be achieved by applying longer chlorination times or increasing the amount of uranium loaded in the anode basket. Overall, the chlorine cathode can be used with an appropriately designed anode to chlorinate uranium in situ for synthesis of molten salt reactor fuel salts.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Field Testing LIDAR Based Feed-Forward Controls on the NREL Controls Advanced Research Turbine: Preprint

Wind turbines are complex, nonlinear, dynamic systems driven by aerodynamic, gravitational, centrifugal, and gyroscopic forces. The aerodynamics of wind turbines are nonlinear, unsteady, and complex. Turbine rotors are subjected to a chaotic three-dimensional (3-D) turbulent wind inflow field with imbedded coherent vortices that drive fatigue loads and reduce lifetime. In order to reduce cost of energy, future large multimegawatt turbines must be designed with lighter weight structures, using active controls to mitigate fatigue loads, maximize energy capture, and add active damping to maintain stability for these dynamically active structures operating in a complex environment. Researchers at the National Renewable Energy Laboratory (NREL) and University of Stuttgart are designing, implementing, and testing advanced feed-back and feed-forward controls in order to reduce the cost of energy for wind turbines.

17 WIND ENERGY↗
DOE OSTI2025

Study of the Design and Characteristics of a Modified Pulsed Plasma Thruster with Graphite and Tungsten Trigger Electrodes

The paper presents experimental results for a modified pulsed plasma thruster (PPT) with solid propellant, using a coaxial anode–cathode design. Graphite from pencil leads served as propellant, and a tungsten trigger electrode was tested to reduce carbonization effects. Experiments were performed in a vacuum chamber at 0.001 Pa, employing diagnostics such as discharge current/voltage recording, power measurement, ballistic pendulum, time-of-flight (TOF) method, and a Faraday cup. Current and voltage waveforms matched an oscillatory RLC circuit with variable plasma channel resistance. Key discharge parameters were measured, including current pulse duration/amplitude and plasma channel formation/decay dynamics. Impulse bit values, obtained with a ballistic pendulum, reached up to 8.5 μN·s. Increasing trigger capacitor capacitance reduced thrust due to unstable “pre-plasma” formation and partial pre-discharge energy loss. Using TOF and Faraday cup diagnostics, plasma front velocity, ion current amplitude, current density, and ion concentration were determined. Tungsten electrodes produced lower charged particle concentrations than graphite but offered better adhesion resistance, minimal carbonization, and stable long-term performance. The findings support optimizing trigger electrode materials and PPT operating modes to extend lifetime and stabilize thrust output.

Faraday cup↗
DOE OSTI2021

Tools for pressure core sub-coring and pore-scale micro-CT (computed tomography) scans

Abstract. The pore habits of gas hydrate in natural sediment matrices provide essential clues for understanding physical (mechanical, thermal, hydraulic, and electrical) properties of hydrate-bearing sediments, yet there are no tools that can directly visualize the pore habits of natural gas hydrate other than indirect interpretation based on core-scale or field-scale observations. A significant challenge is to obtain a mini-core from pressure cores retrieved from natural reservoirs for high-resolution micro-CT (computed tomography) scans while maintaining pressure and temperature conditions required for stability of gas hydrate during all operational steps including manipulation, cutting, transferring, sub-coring and CT scanning. We present a new set of tools for pore-scale micro-CT imaging of natural hydrate-bearing sediments while maintaining pressure and temperature control. The tests with laboratory-prepared cores and pressure cores successfully demonstrate the capability of this set of tools to subsample a mini-core from pressure cores, transfer the mini-core to an X-ray transparent core holder, and conduct micro-CT scans. Successfully obtained CT images prove the functionality of this set of tools.

Seol, Yongkoo↗
DOE OSTI2015

Devices, systems, and methods for conducting assays with improved sensitivity using sedimentation

Embodiments of the present invention are directed toward devices, systems, and method for conducting assays using sedimentation. In one example, a method includes layering a mixture on a density medium, subjecting sedimentation particles in the mixture to sedimentation forces to cause the sedimentation particles to move to a detection area through a density medium, and detecting a target analyte in a detection region of the sedimentation channel. In some examples, the sedimentation particles and labeling agent may have like charges to reduce non-specific binding of labeling agent and sedimentation particles. In some examples, the density medium is provided with a separation layer for stabilizing the assay during storage and operation. In some examples, the sedimentation channel may be provided with a generally flat sedimentation chamber for dispersing the particle pellet over a larger surface area.

42 ENGINEERING↗
DOE OSTI2016

Devices, systems, and methods for conducting assays with improved sensitivity using sedimentation

Embodiments of the present invention are directed toward devices, systems, and method for conducting assays using sedimentation. In one example, a method includes layering a mixture on a density medium, subjecting sedimentation particles in the mixture to sedimentation forces to cause the sedimentation particles to move to a detection area through a density medium, and detecting a target analyte in a detection region of the sedimentation channel. In some examples, the sedimentation particles and labeling agent may have like charges to reduce non-specific binding of labeling agent and sedimentation particles. In some examples, the density medium is provided with a separation layer for stabilizing the assay during storage and operation. In some examples, the sedimentation channel may be provided with a generally flat sedimentation chamber for dispersing the particle pellet over a larger surface area.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Performance Impact of Fast Flow Paths Through Grout Monoliths Used for Radioactive Waste Disposal - 13224

Empty HLW handling and storage tanks at SRS and INL contain residual radioactivity; these tanks are being stabilized with cementitious grout during closure operations. The US NRC directed the Center for Nuclear Waste Regulatory Analyses (CNWRA{sup R}) to develop physical analogs of cementitious grout monoliths to investigate their potential to form fast flow pathways such as macro-cracks, separations between grout lifts, and annuli around pipes, supports, and along tank walls. CNWRA developed and tested 15 55-gal-drum-scale specimens and 2 larger specimens of tank-filling cementitious grout, and 9 specimens of pipe-filling grout. These experiments demonstrated that the size of fast flow pathways that develop and the peak temperatures attained during hydration are proportional to the scale of the specimen, and that annular apertures and bulk grout permeability generally increased with time post-placement. Cracks developed overnight following placement of each grout lift in the largest specimen, but developed more slowly in smaller specimens, perhaps due to a ∼20 deg. C difference in peak temperatures, which influence the thermal gradients that can induce cracking. Plastic and drying shrinkage commonly led to poor grout-to-metal and grout-to-grout bonding. Cracks, annular gaps, and grout flow lobe seams transmitted fluids during injection testing. Macro-scale flow pathways such as these are not readily observed in bench-scale specimens of cementitious tank grout. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Effect of Pressure on Structure and Extinction of Counterflow Premixed Ammonia/Air Flames

With the growing interest in ammonia as a carbon-free fuel, numerous recent research efforts on fundamental combustion characteristics of ammonia have been reported. Despite this attention, there remain fundamental aspects that lack experimental investigation or validated chemical kinetic models. Specifically, the understanding of ammonia flame structure and the quantification of extinction limits at elevated pressures are incomplete. Furthermore, the chemistry of NOx in relation to ammonia flames has not been thoroughly examined, especially at pressure, and it is useful to explore the operating conditions that exhibit favorable flame stability with minimal NOx formation. In the current work, key characteristics of ammonia/air combustion, including strain-induced extinction limits and NO* chemiluminescence, are experimentally investigated over a wide range of equivalence ratios and pressures. This paper presents initial results in a study directed to improved comprehension of ammonia combustion chemistry, and acquisition of new datasets under elevated pressure and temperature conditions, to better refine rate expressions for important reactions in ammonia combustion.

08 HYDROGEN↗
DOE OSTI2019

Mercury Speciation via Direct Mercury Analyzer

Mercury has no known biological role, but is present in every living thing and widespread in the environment. As mercury enters an aqueous system, it is subject to methylation or demethylation. Methylmercury selectively partitions into biota and biomagnifies through the food chain. Nearly all methylmercury exposures in the U.S. occur through eating fish and shellfish that contain higher levels of methylmercury. Methyl mercury and other organomercury compounds are more toxic than inorganic mercury. Thus, monitoring and understanding mercury speciation are key to effective environmental management. It is particularly important to be able to separate and measure bioaccumulative-toxic species of mercury such as methyl mercury. We are developing a protocol for utilizing the Direct Mercury Analyzer (DMA-80) for mercury speciation of water samples and to monitor methylmercury (meHg). Objectives: - Advance the understanding of the performance of the direct mercury analysis (DMA) under a range of DOE relevant water chemistry conditions to quantify total mercury: - Demonstrate the applicability of DMA to analysis of typical DOE high level liquid 'tank' waste samples using nonradioactive simulants; Test innovative sorbents to extend the range of the direct mercury analyzer to environmental concentration levels. - Perform scoping tests to demonstrate proof of principle for the chemical reduction amalgamation modular microcolumns for mercury speciation: Examine various microcolumn configurations and document speciation performance for typical DOE high level liquid 'tank' waste samples using nonradioactive simulants; Perform tests to examine extending the speciation paradigm to environmental concentration levels. General Method: all samples analyzed using a direct mercury analyzer (DMA 80) which automates the following steps: 1) pyrolysis to release the mercury, 2) catalysis to convert all mercury to elemental, 3) amalgamation to trap the mercury, 4) desorption to release the mercury as a pulse and 5) spectroscopy to detect the mercury.. Instrument analyzes all mercury species in solids and liquids. The DMA 'eliminates' sample preparation, reduces labor, decreases waste, and results in more practical and cost effective methods. To test the performance of the DMA for DOE relevant conditions, we analyzed samples representative of at high (mg/L) tank waste concentrations in water and in diluted tank waste simulant and analyzed samples representative of environmental (ng/L levels) in water. High concentration samples were analyzed directly in the instrument. Low concentration samples were analyzed by concentrating the mercury onto sorbents such as silica thiol or a mixture of silica thiol and copper. The concentration was performed using microcolumns and placing the columns into the DMA (see below) or by mixing the sorbent into the bulk sample and then filtering ad analyzing the filter in the DMA. Speciation Methods: The speciation tests were based on the selective reduction of inorganic mercury ions - Hg{sup (+} {sup or} {sup 2+)} - to elemental mercury - Hg(0). The elemental mercury is then trapped by amalgamation into the metal. These reactions do not impact methyl mercury allowing for separation. All reactions were performed using powdered elemental copper. To demonstrate proof-of-principle for the selective collection of inorganic mercury, samples were exposed to different amounts of powdered copper (and a control with no copper). This was done using microcolumns and a vacuum box. The columns were placed directly on the DMA for analysis. All materials and conditions were tested using solutions of both inorganic mercury and methyl mercury and all trials were in triplicate. Results and Observations: Validated DMA for high concentration Hg samples such as DOE tank waste: - Liquid inHg - samples were stable on autosampler carousel and results were accurate; - Liquid meHg - samples required a stabilizer. Si-Thiol (0.02 g) in the sample boat generated reliable meHg results. Stabilizer can be added for routine operations. Successful 'proof of principal' in extending DMA range to near environmental levels - using both microcolumns and filtration; - Filtration - Adding Si-Thiol (0.5 g) to sample extracted both inHg and meHg and preserved sample. Handling filters was labor intensive. - Microcolumns - best performance using a combination of copper and Si-Thiol - columns clogged and flowed slowly in some cases; - Practical limit may be in the range of 1 to 5 ng/L due to blanks; - Path Forward - Test additional packing materials and methods to improve flow and consistency, and approaches to minimize blanks. Successful 'proof of principal' for Hg speciation using chemical reduction and amalgamation; - Copper microcolumns (0.5 g Cu) selectively trapped inHg for high concentration mercury samples; - Copper microcolumns (0.5 g Cu selectively trapped inHg for large volume samples at environmental concentrations; - Some sorption of me Hg so that separations not quantitative; - Path Forward - test additional packing materials and alternate eluents to better trap inHg and minimize meHg retention in column.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗