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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Bioreactor tests preliminary to landfill in situ aeration: A case study

Highlights: ► Carbon and nitrogen mass balances in aerated landfill simulation reactors. ► Waste stabilization in aerated landfill simulation reactors. ► Effect of temperature on biodegradation processes in aerated landfills. - Abstract: Lab scale tests in bioreactor were carried out in the framework of the characterization studies of a landfill where in situ aeration (possibly followed by landfill mining) had been proposed as part of the novel waste management strategy in a region in northern Italy. The tests were run to monitor the effects produced by aerobic conditions at different temperatures on waste sampled at different depths in the landfill, with focus on the carbon and nitrogen conversion during aeration. Temperatures ranging from 35 to 45 °C were chosen, in order to evaluate possible inhibition of biodegradation processes (namely nitrification) at 45 °C in the landfill. The results obtained showed positive effects of the aeration on leachate quality and a significant reduction of waste biodegradability. Although a delay of biodegradation processes was observed in the reactor run at 45 °C, biodegradation rates increased after 2 months of aeration, providing very low values of the relevant parameters (as in the other aerated reactors) by the end of the study. Mass balances were carried out for TOC and N-NH{sub 4}{sup +}; the findings obtained were encouraging and provided evidence of the effectiveness of carbon and nitrogen conversion processes in the aerated landfill simulation reactors.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Homogeneous Nucleation of Ice in Transiently-Heated, Supercooled Liquid Water Films

e have investigated the nucleation and growth of crystalline ice in 0.24 µm thick, supercooled water films deposited on Pt(111) at cryogenic temperatures. The films were heated with ~10 ns infrared laser pulses, which produced typical heating and cooling rates of ~109 – 1010 K/s. The crystallization of these water films was monitored with infrared spectroscopy. The experimental conditions were chosen such that ice nucleation at the water/metal interface was suppressed and nucleation at the water/vacuum interfaces did not affect the observations. Since the water films were flat, their internal pressure was not raised due to curvature effects. Therefore, the experiments were sensitive to the homogeneous ice nucleation rate in the temperature range from ~210 K to 225 K. The experiments show that the maximum for the homogeneous ice nucleation rate versus temperature, Jmax, needs to be = 1026 m-3s-1 and is likely to be ~1029±2 m-3s-1. We argue that such large nucleation rates are consistent with experiments on hyperquenched glassy water, which typically have crystalline fractions of ~1% or more.

Xu, Yuntao↗
DOE OSTI2026

Using Domain Insertion to Create Sulfite Reductases That Present Chemical-Dependent Activities

Domain insertion can be used to create oxidoreductases whose activities are dependent upon analyte binding. To date, most domain insertion studies have targeted relatively small oxidoreductases of known structure, so it remains unclear how to apply this protein engineering approach to large hetero-oligomeric proteins that require dynamic conformational changes for catalysis. To address this question, we studied the effects of peptide and domain insertions on the activity of NADPH-dependent sulfite reductase (SiR) from Escherichia coli, a dodecameric oxidoreductase containing four hemoprotein and eight flavoprotein subunits. SiR mutational tolerance was first evaluated using systematic octapeptide insertion and a cellular selection, which identified regions across the hemoprotein structure that retain parent-like activity following insertion. When a ligand-binding domain was inserted at backbone locations tolerant to peptide insertion, including sites proximal and distal from the intersubunit interfaces, ∼90% retained catalytic activity, and >50% presented activity that is regulated by an endocrine disruptor. With one domain insertion variant, the conditional production of sulfide could be monitored electrochemically from cells using a bioelectrochemical reactor. These results show how systematic peptide insertion can be used to inform domain insertion in a large heterooligomeric protein complex, and they illustrate how SiR can be engineered to convert chemical information in the environment into a redox-active metabolite that diffuses across the cell membrane.

bacteria↗
DOE OSTI2020

Low-loss superconducting titanium nitride grown using plasma-assisted molecular beam epitaxy

Titanium nitride (TiN) is a known superconducting material that is attractive for use as passive components in superconducting circuits for both conventional and quantum information devices. In contrast to conventional synthesis techniques, here, plasma-assisted molecular beam epitaxy is reported to produce high-quality TiN on bare silicon wafers. Using a rf-plasma source to crack the nitrogen molecules and a conventional high-temperature effusion cell for titanium, TiN growth is completed under nitrogen-rich conditions. The growth and nucleation is monitored in situ, while the structure and composition are characterized using x-ray diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and scanning transmission electron microscopy. The stoichiometric TiN (111) films sit on an amorphous nitride layer with low impurity concentrations. The films superconduct with Tc=5.4 K, and coplanar waveguide resonators are fabricated with a small center width of 6 μm that demonstrate single-photon quality factors approaching 1M and high-power quality factors over 5M without observing saturation.

Richardson, C. J. K. (ORCID:0000000188175347)↗
DOE OSTI2019

Distribution System State Estimation: A Semidefinite Programming Approach

Distribution system state estimation (DSSE) is one of the vital components in the next-generation distribution management system which allows operators to monitor the entire system's operating conditions. Due to the lack of real-time measurements, DSSE has to process measurements whose quality varies significantly across different sources, which causes a convergence issue to the Gauss-Newton solver. In this paper, a semidefinite programming (SDP) framework is proposed to reformulate the DSSE problem into a rank- constrained SDP problem. One challenge of this technique is the nonconvex rank-one constraint, which is generally relaxed. However, the relaxed SDP-DSSE problem cannot guarantee a rank-one solution and hence loses optimality. Therefore, we propose two solution approaches to obtain rank-one solutions for the SDPDSSE problem: the rank reduction approach and the convex iteration approach. The model and the effectiveness of the proposed solution approaches are numerically demonstrated on the IEEE 13-bus, 34-bus, and 123-bus distribution systems.

convex iteration↗
DOE OSTI2023

Mathematical Framework Underlying the In Situ Electrochemical Diagnosis of Adsorbed Intermediates Formed during Redox Reactions at Electrode Surfaces

Previously, we have presented an electrochemical technique wherein an electroactive tracer species is employed to probe the rate-limiting factors governing redox reactions at an electrode surface. In this technique, the electrode is first held potentiostatically to facilitate a redox process (step 1), and then the potential is released to open circuit conditions (step 2) so as to monitor the time-dependent re-equilibration of the electrode potential in the presence of the tracer. The time-dependent potential response in step 2 has been shown to contain information about diffusion—limited or desorption—limited steps, enabling in situ probing of the electrochemistry at the electrode surface during step 1. In the present contribution, a theoretical model governing the transient response in step 2 is developed for two limiting cases: diffusion—limited and desorption—limited recovery of the electrode potential. Mathematical modeling shows that, during re-equilibration, the step 2 potential transient corresponding to a case where step 1 involves surface adsorbed species which undergo desorption in step 2 exhibits a much longer time constant than that when re-equilibration occurs under diffusion limitations. The mathematical framework presented herein provides a sound fundamental basis for applying the aforementioned technique to studying adsorption-desorption processes during electrochemistry. Also, technique limitations are presented in light of the modeling findings.

25 ENERGY STORAGE↗
DOE OSTI2019

Fast Charging of Li-Ion Cells: Part I. Using Li/Cu Reference Electrodes to Probe Individual Electrode Potentials

Increasing the charge rate of Li-ion cells over 1–2C (full charge in 30–60 min) would be highly desirable, but high currents flowing through the active materials push these cells to their endurance limits. In this article, we aim to understand how such high-current regimes affect electrochemical properties of the cells. Formation of Li metal deposits is a recognized hazard of high-rate charging, as Li plating can overtake lithium intercalation in the negative electrode. Here we demonstrate how microprobe Li/Cu reference electrodes can be used to characterize the graphite anode and layered oxide (NCM523) cathode during constant-current (≤ 6C) voltage-limited (4.39 V) charging of Li-ion cells. These reference electrodes are used to monitor the onset of Li plating conditions in situ during cell charging. As the current increases over 3C, the anode potentials decrease below -40 mV causing lithium nucleation. Surprisingly, this nucleation (at least, initially) does not result in capacity fade or a higher anode impedance even in strongly polarized cells, so it appears that the nascent Li nuclei are isolated from electrolyte by the pre-existing solid electrolyte interphase. Our study shows that microprobe reference electrodes are an important diagnostic tool to characterize full-cell behavior in the high-current regimes.

25 ENERGY STORAGE↗
DOE OSTI2011

Optimization of Preprocessing and Densification of Sorghum Stover at Full-scale Operation

Transportation costs can be a prohibitive step in bringing biomass to a preprocessing location or biofuel refinery. One alternative to transporting biomass in baled or loose format to a preprocessing location, is to utilize a mobile preprocessing system that can be relocated to various locations where biomass is stored, preprocess and densify the biomass, then ship it to the refinery as needed. The Idaho National Laboratory has a full scale 'Process Demonstration Unit' PDU which includes a stage 1 grinder, hammer mill, drier, pellet mill, and cooler with the associated conveyance system components. Testing at bench and pilot scale has been conducted to determine effects of moisture on preprocessing, crop varieties on preprocessing efficiency and product quality. The INLs PDU provides an opportunity to test the conclusions made at the bench and pilot scale on full industrial scale systems. Each component of the PDU is operated from a central operating station where data is collected to determine power consumption rates for each step in the process. The power for each electrical motor in the system is monitored from the control station to monitor for problems and determine optimal conditions for the system performance. The data can then be viewed to observe how changes in biomass input parameters (moisture and crop type for example), mechanical changes (screen size, biomass drying, pellet size, grinding speed, etc.,), or other variations effect the power consumption of the system. Sorgum in four foot round bales was tested in the system using a series of 6 different screen sizes including: 3/16 in., 1 in., 2 in., 3 in., 4 in., and 6 in. The effect on power consumption, product quality, and production rate were measured to determine optimal conditions.

09 BIOMASS FUELS↗
DOE OSTI2015

Additive manufacturing of materials: Opportunities and challenges

Additive manufacturing (also known as 3D printing) is considered a disruptive technology for producing components with topologically optimized complex geometries as well as functionalities that are not achievable by traditional methods. The realization of the full potential of 3D printing is stifled by a lack of computational design tools, generic material feedstocks, techniques for monitoring thermomechanical processes under in situ conditions, and especially methods for minimizing anisotropic static and dynamic properties brought about by microstructural heterogeneity. In this paper, we discuss the role of interdisciplinary research involving robotics and automation, process control, multiscale characterization of microstructure and properties, and high-performance computational tools to address each of these challenges. In addition, emerging pathways to scale up additive manufacturing of structural materials to large sizes (>1 m) and higher productivities (5–20 kg/h) while maintaining mechanical performance and geometrical flexibility are also discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Iterative Strategies for Aftershock Classification in Automatic Seismic Processing Pipelines

We report aftershock sequences following very large earthquakes present enormous challenges to near-real-time generation of seismic bulletins. The increase in analyst resources needed to relocate an inflated number of events is compounded by failures of phase-association algorithms and a significant deterioration in the quality of underlying, fully automatic event bulletins. Current processing pipelines were designed a generation ago, and, due to computational limitations of the time, are usually limited to single passes over the raw data. With current processing capability, multiple passes over the data are feasible. Processing the raw data at each station currently generates parametric data streams that are then scanned by a phase-association algorithm to form event hypotheses. We consider the scenario in which a large earthquake has occurred and propose to define a region of likely aftershock activity in which events are detected and accurately located, using a separate specially targeted semiautomatic process. This effort may focus on so-called pattern detectors, but here we demonstrate a more general grid-search algorithm that may cover wider source regions without requiring waveform similarity. Given many well-located aftershocks within our source region, we may remove all associated phases from the original detection lists prior to a new iteration of the phase-association algorithm. We provide a proof-of-concept example for the 2015 Gorkha sequence, Nepal, recorded on seismic arrays of the International Monitoring System. Even with very conservative conditions for defining event hypotheses within the aftershock source region, we can automatically remove about half of the original detections that could have been generated by Nepal earthquakes and reduce the likelihood of false associations and spurious event hypotheses. Lastly, further reductions in the number of detections in the parametric data streams are likely, using correlation and subspace detectors and/or empirical matched field processing.

58 GEOSCIENCES↗
DOE OSTI2011

Light Water Reactor Sustainability Program Power Uprate Research and Development Strategy

The economic incentives for low-cost electricity generation will continue to drive more plant owners to identify safe and reliable methods to increase the electrical power output of the current nuclear power plant fleet. A power uprate enables a nuclear power plant to increase its electrical output with low cost. However, power uprates brought new challenges to plant owners and operators. These include equipment damage or degraded performance, and unanticipated responses to plant conditions, etc. These problems have arisen mainly from using dated design and safety analysis tools and insufficient understanding of the full implications of the proposed power uprate or from insufficient attention to detail during the design and implementation phase. It is essential to demonstrate that all required safety margins have been properly retained and the existing safety level has been maintained or even increased, with consideration of all the conditions and parameters that have an influence on plant safety. The impact of the power uprate on plant life management for long term operation is also an important issue. Significant capital investments are required to extend the lifetime of an aging nuclear power plant. Power uprates can help the plant owner to recover the investment costs. However, plant aging issues may be aggravated by the power uprate due to plant conditions. More rigorous analyses, inspections and monitoring systems are required.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2011

Final Technical Report: Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project

This report summarizes the work conducted under U.S. Department of Energy (DOE) under contract DE-FC36-04GO14285 by Mercedes-Benz & Research Development, North America (MBRDNA), Chrysler, Daimler, Mercedes Benz USA (MBUSA), BP, DTE Energy and NextEnergy to validate fuel cell technologies for infrastructure, transportation as well as assess technology and commercial readiness for the market. The Mercedes Team, together with its partners, tested the technology by operating and fueling hydrogen fuel cell vehicles under real world conditions in varying climate, terrain and driving conditions. Vehicle and infrastructure data was collected to monitor the progress toward the hydrogen vehicle and infrastructure performance targets of $2.00 to 3.00/gge hydrogen production cost and 2,000-hour fuel cell durability. Finally, to prepare the public for a hydrogen economy, outreach activities were designed to promote awareness and acceptance of hydrogen technology.

02 PETROLEUM↗
DOE OSTI2013

Innovative Water Management Technology to Reduce Environmental Impacts of Produced Water

Clemson University with Chevron as an industry partner developed and applied treatment technology using constructed wetland systems to decrease targeted constituents in simulated and actual produced waters to achieve reuse criteria and discharge limits. Pilot-scale and demonstration constructed wetland treatment system (CWTS) experiments led to design strategies for treating a variety of constituents of concern (COCs) in produced waters including divalent metals, metalloids, oil and grease, and ammonia. Targeted biogeochemical pathways for treatment of COCs in pilot-scale CWTS experiments included divalent metal sulfide precipitation through dissimilatory sulfate reduction, metal precipitation through oxidation, reduction of selenite to insoluble elemental selenium, aerobic biodegradation of oil, nitrification of ammonia to nitrate, denitrification of nitrate to nitrogen gas, separation of oil using an oilwater separator, and sorption of ammonia to zeolite. Treatment performance results indicated that CWTSs can be designed and built to promote specific environmental and geochemical conditions in order for targeted biogeochemical pathways to operate. The demonstration system successfully achieved consistent removal extents even while inflow concentrations of COCs in the produced water differed by orders of magnitude. Design strategies used in the pilot-scale and demonstration CWTSs to promote specific conditions that can be applied to designing full-scale CWTSs include plant and soil selection, water-depth selection, addition of amendments, and hydraulic retention time (HRT). These strategies allow conditions within a CWTS to be modified to achieve ranges necessary for the preferred biogeochemical treatment pathways. In the case of renovating a produced water containing COCs that require different biogeochemical pathways for treatment, a CWTS can be designed with sequential cells that promote different conditions. For example, the pilot-scale CWTS for post-reverse osmosis produced water was designed to promote oxidizing conditions within the first wetland cell for nitrification of ammonia, and the subsequent three cells were designed to promote reducing conditions for denitrification of nitrate. By incorporating multiple wetland cells in a CWTS, the conditions within each cell can be modified for removal of specific COCs. In addition, a CWTS designed with multiple cells allows for convenient sample collection points so that biogeochemical conditions of individual cells can be monitored and performance evaluated. Removal rate coefficients determined from the pilot-scale CWTS experiments and confirmed by the demonstration system can be used to calculate HRTs required to treat COCs in full-scale CWTSs. The calculated HRTs can then be used to determine the surface area or "footprint" of a full-size CWTS for a given inflow rate of produced water.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Working Toward a Precision Neutrino Beam [Slides]

As the Deep Underground Neutrino Experiment nears construction, the existing neutrino facilities at Fermilab provide opportunities to test and refine methods characterizing high precision neutrino beams. MARGARITA is a water Cherenkov stopped muon detector that features twin photomultiplier tubes and two small, slightly differing detector volumes. The two detector volumes are designed to exploit the difference between the lifetimes of positive and negative muons in matter in order to characterize a neutrino beam. MARGARITA is currently being developed in the Neutrinos at the Main Injector (NuMI) beamline. The NuMI beamline also contains an existing muon monitoring system that has been underutilized. Improved analysis via ROOT and simulation via Geant4 of past, current, and future data from the muon monitors during an array of operating conditions could provide useful insights for any experiment at Fermilab utilizing a precision neutrino beam.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Measurement of Close-in Ground Motion from an Underground Chemical Explosion

Understanding the geophysical response near an underground explosion is crucial for generating insights into the source and emplacement conditions that produce distinct observations in monitoring scenarios occurring at greater distances. Recently, Shot A of the Low Yield Nuclear Monitoring (LYNM) Physics Experiment 1 (PE1) series was conducted at the Nevada National Security Site to provide ground truth for subsurface explosion signal models. This experiment resulted in measuring near-source ground motion at distances ranging from 70 to 1000 m/kt with a 99% success rate, yielding high-fidelity knowledge of the near-field response that can serve as benchmarks for future numerical modeling and experiment planning. However, technical challenges exist in observing near-source phenomena while safeguarding sensitive data acquisition components from the detrimental effects of ground motion in the subsurface. This report outlines tools and techniques to address challenges associated with observing near-source accelerations and within the tunnel drift of the PE1 test bed. Additionally, we describe key systems designed with both modern advancements and legacy guidance to maximize the collection of high-quality ground motion data, which may be applied to constitutive and computational models, leading to new or improved understanding of the near- and far-field signals produced by underground explosions.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2020

TITUS: Visualization of Neutrino Events in Liquid Argon Time Projection Chambers

The amount and complexity of data recorded by high energy physics experiments are rapidly growing, and with these grow the difficulties in visualizing such data. To study the physics of neutrinos, a type of elementary particle, scientists use liquid argon time projection chamber (LArTPC) detectors, among other technologies. LArTPCs have a very high spatial resolution and resolve many of the elementary particles that come out of a neutrino interacting within the argon in the detector. Visualizing these neutrino interactions is of fundamental importance to understanding the properties of neutrinos, but also monitoring and checking on the detector conditions and operations. From these ideas, we have developed TITUS, an event display that shows images recorded by these neutrino detectors. TITUS is a piece of software that reads data coming from LArTPC detectors (as well as the corresponding simulation) and allows users to explore such data in multiple ways. TITUS is flexible to enable fast prototyping and customization.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1966

Shaft encoder presents digital output

Circuits that include compensation circuitry time a capacitance relative to a reference voltage so that a digital presentation occurs that is representative of the positional condition of the mechanical shaft being monitored. This circuitry may be employed in multiples to furnish binary encoding of a number of rotating devices simultaneously.

Hillis, D. A.↗