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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Techno Economic Analysis for Production of Renewable Natural Gas and Value-Added Chemicals from Forest Biomass Residues (CRADA Final Report)

West Biofuels - in collaboration with the University of California San Diego, the University of California Davis, the National Laboratory of the Rockies (NLR), the Colorado School of Mines’ Center for Hydrate Research, Placer County Air Pollution Control District, the Sierra Business Council, and the Southern California Gas Company (SoCalGas)-will demonstrate an innovative pathway to convert forest biomass to renewable gas (RG). The project, Production of Pipeline Grade Renewable Natural Gas and Value-Added Chemicals from Forest Biomass Residues, will utilize an existing pilot-scale gasification system and data and lessons learned from a lab-scale catalytic reactor design, develop, and demonstrate an integrated pilot-scale RG process with a scaled-up catalytic reactor and hydrate-based gas separation process. This robust and simple process uses a commercial proven gasifier, a commercially available catalyst that can tolerate gas contaminants, and a gas separation process that simplifies the downstream processing. Current testing has shown that the process can yield a large amount of methane rich renewable gas in addition to a mixture of propanol, ethanol and other higher alcohols and the relative amounts can be controlled by shifting the process conditions. This process is novel and groundbreaking because the product mixture of RG and valuable alcohols byproducts makes RG production economically feasible at $\$$12 per million British thermal units (MMBtu) or less using forest biomass from high hazard zones.

09 BIOMASS FUELS↗
DOE OSTI2013

Pressure Swing Absorption Device and Process for Separating CO 2 from Shifted Syngas and its Capture for Subsequent Storage

Using the ionic liquid (IL) 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]) as the absorbent on the shell side of a membrane module containing either a porous hydrophobized ceramic tubule or porous hydrophobized polyether ether ketone (PEEK) hollow fiber membranes, studies for CO 2 removal from hot simulated pre-combustion shifted syngas were carried out by a novel pressure swing membrane absorption (PSMAB) process. Helium was used as a surrogate for H 2 in a simulated shifted syngas with CO 2 around 40% (dry gas basis). In this cyclic separation process, the membrane module was used to achieve non-dispersive gas absorption from a high-pressure feed gas (689-1724 kPag; 100-250 psig) at temperatures between 25-100°C into a stationary absorbent liquid on the module shell side during a certain part of the cycle followed by among other cycle steps controlled desorption of the absorbed gases from the liquid in the rest of the cycle. Two product streams were obtained, one He-rich and the other CO 2 -rich. Addition of polyamidoamine (PAMAM) dendrimer of generation 0 to IL [bmim][DCA] improved the system performance at higher temperatures. The solubilities of CO 2 and He were determined in the ionic liquid with or without the dendrimer in solution as well as in the presence or absence of moisture; polyethylene glycol (PEG) 400 was also studied as a replacement for the IL. The solubility selectivity of the ionic liquid containing the dendrimer for CO 2 over helium was considerably larger than that for the pure ionic liquid. The solubility of CO 2 and CO 2 -He solubility selectivity of PEG 400 and a solution of the dendrimer in PEG 400 were higher than the corresponding ones in the IL, [bmim][DCA]. A mathematical model was developed to describe the PSMAB process; a numerical solution of the governing equations described successfully the observed performance of the PSMAB process for the pure ionic liquid-based system.

08 HYDROGEN↗
DOE OSTI2015

Cation-Dependent Stabilization of Electrogenerated Naphthalene Diimide Dianions in Porous Polymer Thin Films and Their Application to Electrical Energy Storage

Porous polymer networks (PPNs) are attractive materials for capacitive energy storage because they offer high surface areas for increased double-layer capacitance, open structures for rapid ion transport, and redox-active moieties that enable faradaic (pseudocapacitive) energy storage. Here we demonstrate a new attractive feature of PPNs—the ability of their reduced forms (radical anions and dianions) to interact with small radii cations through synergistic interactions arising from densely packed redox-active groups, only when prepared as thin films. When naphthalene diimides (NDIs) are incorporated into PPN films, the carbonyl groups of adjacent, electrochemically generated, NDI radical anions and dianions bind strongly to K+, Li+, and Mg2+, shifting the formal potentials of NDI’s second reduction by 120 and 460 mV for K+ and Li+-based electrolytes, respectively. In the case of Mg2+, NDI’s two redox waves coalesce into a single two-electron process with shifts of 240 and 710 mV, for the first and second reductions, respectively, increasing the energy density by over 20 % without changing the polymer backbone. In contrast, the formal reduction potentials of NDI derivatives in solution are identical for each electrolyte, and this effect has not been reported for NDI previously. This study illustrates the profound influence of the solid-state structure of a polymer on its electrochemical response, which does not simply reflect the solution-phase redox behavior of its monomers.

36 MATERIALS SCIENCE↗
DOE OSTI2021

The evolution of seafloor venting from hydrate-sealed gas reservoirs

Here we use 3D seismic data to show that three rows of seafloor gas mounds can be traced downward to leak points that lie at the hydrate-gas contact within three individual dipping coarse-grained sand bodies in the Terrebonne Basin, Walker Ridge block 313, northern Gulf of Mexico. We predict the overpressure within the sand bodies by assuming that the gas pressure at the vent points equal the least principal stress. We interpret that free gas accumulates at the base of the hydrate stability zone, trapped by the overlying sand which has a high methane hydrate saturation. The free gas accumulates until the gas pressure at the base of the hydrate stability zone reaches the least principal stress in the overlying mudrock, whereupon hydraulic fractures form and fluids are vented to the surface. The warm rising fluids and perhaps localized exothermic formation of hydrate raise the local salinity and temperature. This process progressively shifts the base of the hydrate stability zone to shallower depths and dissociates the hydrate seal within the sand, which creates new leak points and results in the observed migration of the seafloor vents. Within the southwest corner of the Terrebonne Basin, this process has repeated multiple times within the Blue, Orange, and Green sands. Here this study shows how the hydrate stability zone can influence the location of fluid expulsion and in turn be affected by the warm, rising, saline fluids sealed by hydrate.

58 GEOSCIENCES↗
DOE OSTI2023

Surface Processes Control the Fate of Reactive Oxidants Generated by Electrochemical Activation of Hydrogen Peroxide on Stainless-Steel Electrodes

Low-cost stainless-steel electrodes can activate hydrogen peroxide (H 2 O 2 ) by converting it into a hydroxyl radical ( • OH) and other reactive oxidants. At an applied potential of +0.020 V, the stainless-steel electrode produced • OH with a yield that was over an order of magnitude higher than that reported for other systems that employ iron oxides as catalysts under circumneutral pH conditions. Decreasing the applied potential at pH 8 and 9 enhanced the rate of H 2 O 2 loss by shifting the process to a reaction mechanism that resulted in the formation of an Fe(IV) species. Significant metal leaching was only observed under acidic pH conditions (i.e., at pH <6), with the release of dissolved Fe and Cr occurring as the thickness of the passivation layer decreased. Despite the relatively high yield of • OH production under circumneutral pH conditions, most of the oxidants were scavenged by the electrode surface when contaminant concentrations comparable to those expected in drinking water sources were tested. The stainless-steel electrode efficiently removed trace organic contaminants from an authentic surface water sample without contaminating the water with Fe and Cr. With further development, stainless-steel electrodes could provide a cost-effective alternative to other H 2 O 2 activation processes, such as those by ultraviolet light.

42 ENGINEERING↗
DOE OSTI2011

Micro-fluidics and integrated optics glass sensor for in-line micro-probing of nuclear samples

We study the miniaturisation of Thermal Lens Spectrometry (TLS) towards Lab-on-chip integration in order to reduce the volume of fluid assays in nuclear process control. TLS is of great interest in this context since it combines the advantages of optical detection methods with an inherent suitability for small-scale samples. After validating the experimental principle in a classical thermal lens crossed-beam setup, we show the integration of a Young-interferometer with a microcapillary on a glass substrate, reducing the necessary sample size to 400 nl. The interferometer translates the photo-thermally induced refractive index change in the fluid to a phase shift of the fringe pattern, which can then be detected by a camera. Measurements of Co(II) in ethanol yield a detection limit of c = 5 x 10{sup -4} M for the crossed-beam setup and c = 6x10{sup -3} M for the integrated sensor. At an interaction length of 10 {mu}m, it detects a minimum absorbance of AU = 6 x 10{sup -5} in a probed volume of 10 pl. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Coupling Spatiotemporal Community Assembly Processes to Changes in Microbial Metabolism

Community assembly processes govern shifts in species abundances in response to environmental change, yet our understanding of assembly remains largely decoupled from ecosystem function. Here, we test hypotheses regarding assembly and function across space and time using hyporheic microbial communities as a model system. We pair sampling of two habitat types through hydrologic fluctuation with null modeling and multivariate statistics. We demonstrate that dual selective pressures assimilate to generate compositional changes at distinct timescales among habitat types, resulting in contrasting associations of Betaproteobacteria and Thaumarchaeota with selection and with seasonal changes in aerobic metabolism. Our results culminate in a conceptual model in which selection from contrasting environments regulates taxon abundance and ecosystem function through time, with increases in function when oscillating selection opposes stable selective pressures. Our model is applicable within both macrobial and microbial ecology and presents an avenue for assimilating community assembly processes into predictions of ecosystem function.

aerobic respiration↗
DOE OSTI2018

How Do Microphysical Processes Influence Large-Scale Precipitation Variability and Extremes?

Convection permitting simulations using the Model for Prediction Across Scales-Atmosphere (MPAS-A) are used to examine how microphysical processes affect large-scale precipitation variability and extremes. An episode of the Madden-Julian Oscillation is simulated using MPAS-A with a refined region at 4-km grid spacing over the Indian Ocean. It is shown that cloud microphysical processes regulate the precipitable water (PW) statistics. Because of the non-linear relationship between precipitation and PW, PW exceeding a certain critical value (PWcr) contributes disproportionately to precipitation variability. However, the frequency of PW exceeding PWcr decreases rapidly with PW, so changes in microphysical processes that shift the column PW statistics relative to PWcr even slightly have large impacts on precipitation variability. Furthermore, precipitation variance and extreme precipitation frequency are approximately linearly related to the difference between the mean and critical PW values. Thus observed precipitation statistics could be used to directly constrain model microphysical parameters as this study demonstrates using radar observations from DYNAMO field campaign.

58 GEOSCIENCES↗
DOE OSTI2017

On the transcritical mixing of fuels at diesel engine conditions

Whilst the physics of both classical evaporation and supercritical fluid mixing are reasonably well characterized and understood in isolation, little is known about the transition from one to the other in the context of liquid fuel systems. The lack of experimental data for microscopic droplets at realistic operating conditions impedes the development of phenomenological and numerical models. To address this issue we performed systematic measurements using high-speed long-distance microscopy, for three single-component fuels (n-heptane, n-dodecane, n-hexadecane), into gas at elevated temperatures (700–1200 K) and pressures (2–11 MPa). We describe these high-speed visualizations and the time evolution of the transition from liquid droplet to fuel vapour at the microscopic level. The measurements show that the classical atomization and vaporisation processes do shift to one where surface tension forces diminish with increasing pressure and temperature, but the transition to diffusive mixing does not occur instantaneously when the fuel enters the chamber. Rather, subcritical liquid structures exhibit surface tension in the near-nozzle region and then, after time surrounded by the hot ambient gas and fuel vapour, undergo a transition to a dense miscible fluid. Although there was clear evidence of surface tension and primary atomization for n-dodecane and n-hexadecane for a period of time at all the above conditions, n-heptane appeared to produce a supercritical fluid from the nozzle outlet when injected at the most elevated conditions (1200 K, 10 MPa). This demonstrates that the time taken by a droplet to transition to diffusive mixing depends on the pressure and temperature of the gas surrounding the droplet as well as the fuel properties. We summarise our observations into a phenomenological model which describes the morphological evolution and transition of microscopic droplets from classical evaporation through a transitional mixing regime and towards diffusive mixing, as a function of operating conditions. We provide criteria for these regime transitions as reduced pressure–temperature correlations, revealing the conditions where transcritical mixing is important to diesel fuel spray mixing.

02 PETROLEUM↗
DOE OSTI2013

Quantitative x-ray phase imaging at the nanoscale by multilayer Laue lenses

For scanning x-ray microscopy, many attempts have been made to image the phase contrast based on a concept of the beam being deflected by a specimen, the so-called differential phase contrast imaging (DPC). Despite the successful demonstration in a number of representative cases at moderate spatial resolutions, these methods suffer from various limitations that preclude applications of DPC for ultra-high spatial resolution imaging, where the emerging wave field from the focusing optic tends to be significantly more complicated. In this work, we propose a highly robust and generic approach based on a Fourier-shift fitting process and demonstrate quantitative phase imaging of a solid oxide fuel cell (SOFC) anode by multilayer Laue lenses (MLLs). The high sensitivity of the phase to structural and compositional variations makes our technique extremely powerful in correlating the electrode performance with its buried nanoscale interfacial structures that may be invisible to the absorption and fluorescence contrasts.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Cooling field tuned magnetic phase transition and exchange bias-like effect in Y{sub 0.9}Pr{sub 0.1}CrO{sub 3}

Cooling magnetic field dependence of magnetic phase transition has been observed in Y{sub 0.9}Pr{sub 0.1}CrO{sub 3}. G{sub z}F{sub x} order (spin structure of PrCrO{sub 3}) is dominant after zero field cooling (ZFC), whereas G{sub x}F{sub z} order (spin structure of YCrO{sub 3}) is dominant after cooling under a field higher than 100 Oe. Positive/negative exchange bias-like effect, with large vertical shift and small horizontal shift, has been observed after FC/ZFC process. The vertical shift can be attributed to the frozen ordered Pr{sup 3+} and Cr{sup 3+} spins in magnetic domains, because of the strong coupling between Pr{sup 3+} and Cr{sup 3+} sublattices; while the horizontal shift is a result of the pinning of spins at the interfaces. The frozen structure is generated by the field used for the measurement of the initial magnetization curve of M(H) for the ZFC cooled sample, while it is generated by the cooling field for the sample cooled under a cooling field higher than 100 Oe.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Hydroxylation of ZnO/Cu(1 1 1) inverse catalysts under ambient water vapor and the water–gas shift reaction

The interaction of water vapor with ZnO/CuO x /Cu(1 1 1) surfaces was explored using synchrotron-based ambient pressure x-ray photoelectron spectroscopy (AP-XPS) and density-functional theory (DFT) calculations. Cu(1 1 1) does not dissociate the water molecule. Cleavage of O–H bonds was seen with AP-XPS after depositing ZnO or preparing CuO x on the copper substrate. The findings of DFT calculations show unique behavior for ZnO/CuO x /Cu(1 1 1), not seen on Cu(1 1 1), CuO x /Cu(1 1 1) or ZnO(0 0 0). The ZnO/CuO x /Cu(1 1 1) system binds water quite well and exhibits the lowest energy barrier for O–H bond cleavage. The presence of unsaturated Zn cations in the islands of ZnO led to high chemical reactivity. In order to remove the OH from ZnO/CuO x /Cu(1 1 1) and ZnO/Cu(1 1 1) surfaces, heating to elevated temperatures was necessary. At 500–600 K, a significant coverage of OH groups was still present on the surfaces and did react with CO during the water–gas shift (WGS) process. The final state of the sample depended strongly on the amount of ZnO present on the catalyst surface. For surfaces with a ZnO coverage below 0.3 ML, the adsorption of water did not change the integrity of the ZnO islands. On the other hand, for surfaces with a ZnO coverage above 0.3 ML, a ZnO→Zn x OH transformation was observed. This transformation led to a decrease in the WGS catalytic activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Toward polymer upcycling—adding value and tackling circularity

Plastics have revolutionized modern life, but have created a global waste crisis driven by our reliance and demand for low-cost, disposable materials. New approaches are vital to address challenges related to plastics waste heterogeneity, along with the property reductions induced by mechanical recycling. Chemical recycling and upcycling of polymers may enable circularity through separation strategies, chemistries that promote closed-loop recycling inherent to macromolecular design, and transformative processes that shift the life-cycle landscape. Polymer upcycling schemes may enable lower-energy pathways and minimal environmental impacts compared with traditional mechanical and chemical recycling. The emergence of industrial adoption of recycling and upcycling approaches is encouraging, solidifying the critical role for these strategies in addressing the fate of plastics and driving advances in next-generation materials design.

Korley, LaShanda T. J.↗
DOE OSTI2022

Knowledge Transfer and Training in Safeguards for Decommissioned Nuclear Facilities (Project Final Report for FY2022)

The International Atomic Energy Agency (IAEA) applies safeguards to nuclear facilities that are not operating, including those undergoing decommissioning, and the IAEA’s effort in this area is both considerable and increasing. Specifically, the IAEA Department of Safeguards’ Division of Concepts and Planning (SGCP-003: Safeguards Approaches) identified an R&D need to “Develop safeguards implementation guidelines for facilities under decommissioning and safeguards concepts for post-accident facilities under decommissioning”. Nuclear facilities undergoing decommissioning are not exempt from safeguards agreements between the IAEA and Host State, and, accordingly, the requirement for verification of no diversion of nuclear material and detection of undeclared activities at decommissioned facilities remain even after facility shutdown. However, the effort required to meet safeguards objectives diminishes as nuclear material and essential equipment are removed during the decommissioning process which shifts the emphasis from verification of ever-diminishing fissile or source material inventories to verification of changes in facility design and equipment operability.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
DOE OSTI2020

Controls on Soil Organic Matter Degradation and Subsequent Greenhouse Gas Emissions Across a Permafrost Thaw Gradient in Northern Sweden

Warming-induced permafrost thaw could enhance microbial decomposition of previously stored soil organic matter (SOM) to carbon dioxide (CO 2 ) and methane (CH 4 ), one of the most significant potential feedbacks from terrestrial ecosystems to the atmosphere in a changing climate. The environmental parameters regulating microbe-organic matter interactions and greenhouse gas (GHG) emissions in northern permafrost peatlands are however still largely unknown. The objective of this work is to understand controls on SOM degradation and its impact on porewater GHG concentrations across the Stordalen Mire, a thawing peat plateau in Northern Sweden. Here, we applied high-resolution mass spectrometry to characterize SOM molecular composition in peat soil samples from the active layers of a Sphagnum-dominated bog and rich fen sites in the Mire. Microbe-organic matter interactions and porewater GHG concentrations across the thaw gradient were controlled by aboveground vegetation and soil pH. An increasingly high abundance of reduced organic compounds experiencing greater humification rates due to enhanced microbial activity were observed with increasing thaw, in parallel with higher CH 4 and CO 2 porewater concentrations. Bog SOM however contained more Sphagnum-derived phenolics, simple carbohydrates, and organic- acids. The low degradation of bog SOM by microbial communities, the enhanced SOM transformation by potentially abiotic mechanisms, and the accumulation of simple carbohydrates in the bog sites could be attributed in part to the low pH conditions of the system associated with Sphagnum mosses. We show that Gibbs free energy of C half reactions based on C oxidation state for OM can be used as a quantifiable measure for OM decomposability and quality to enhance current biogeochemical models to predict C decomposition rates. We found a direct association between OM chemical diversity and δ 13 C-CH 4 in peat porewater; where higher substrate diversity was positively correlated with enriched δ 13 C-CH 4 in fen sites. Oxidized sulfur-containing compounds, produced by Sphagnum, were further hypothesized to control GHG emissions by acting as electron acceptors for a sulfate-reducing electron transport chain, inhibiting methanogenesis in peat bogs. These results suggest that warming-induced permafrost thaw might increase organic matter lability, in subset of sites that become wetlands, and shift biogeochemical processes toward faster decomposition with an increasing proportion of carbon released as CH 4 .

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Quartz crystal microbalance based on passive frequency to voltage converter

In dynamics of evaporation or drying of microdrops from a solid surface, a faster and precise quartz crystal microbalance (QCM) is needed. The fast QCM based on frequency to voltage converter is an attractive and powerful tool in the investigation of the dynamic regime of evaporation to translate the frequency shift in terms of a continuous voltage change. The frequency shift monitoring in fast QCM applications is a real challenge for electronic processing interface. Originally developed as a frequency shift processing interface, this novel passive frequency to voltage converter can produce faster, stable, and accurate results in regard to the QCM sensor behavior. In this article, the concept and circuit of passive frequency to voltage converter will be explained followed by static and dynamic characterization. Experimental results of microdrops evaporation will be given.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗