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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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Perspectives on the Development of Oxide-Based Photocathodes for Solar Fuel Production
Photoelectrochemical cells (PECs), which use semiconductor electrodes (photoelectrodes) to absorb solar energy and perform chemical reactions, constitute one of the most attractive strategies to produce chemical fuels using renewable energy sources. Oxide-based photoelectrodes specifically have been intensively investigated for the construction of PECs due to their relatively inexpensive processing costs and better stability in aqueous media compared with other types of photoelectrodes. Although there have been many advancements in the development of oxide-based photoanodes, our understanding of oxide-based photocathodes remains limited. The goal of this Perspective is to examine the recent progress made in the field of oxide-based photocathodes and discuss future research directions. The photocathode systems considered here include binary and ternary Cu-based photocathodes and ternary Fe-based photocathodes. Here, we assessed the characteristics and major advantages and drawbacks of each system and identified the most critical research gaps. The insights and discussions provided in this Perspective will serve as useful resources for the design of future studies, leading to the development of more efficient and practical PECs.
Efficient upgrading of CO to C3 fuel using asymmetric C-C coupling active sites
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Nanoscale Analysis of LSM/YSZ Interfaces within Composite Cathodes for Commercial Solid Oxide Fuel Cells
17th International Symposium on Solid Oxide Fuel Cells (SOFC-XVII), Virtual, July 18-23, 2021
Contaminant Cation Effect on Oxygen Transport through the Ionomers of Polymer Electrolyte Membrane Fuel Cells
We characterized the effects of cobalt (Co 2+ ) and other cation contaminants on the oxygen (O 2 ) transport properties of the PFSA ionomer used in polymer electrolyte membrane fuel cells (PEMFCs) and gained insight into the mechanisms by which contaminant cations inhibit O 2 transport. Such cations can be released by alloy catalysts and environmental conditions and pose a significant challenge to maintaining high current density performance with low platinum (Pt) loadings. We used a test cell capable of isolating the ionomer from the membrane electrode assembly (MEA), allowing for O 2 transport resistance (R O2 ) measurements using a limiting current technique. We contaminated ionomer membranes with Li + , Na + , Ni 2+ , Co 2+ , and Ce 3+ and found a general increase in R O2 for increased contamination levels and decreased water activity. In addition, our Co 2+ results indicated distinct concentration-dependent regimes. The other cation-form ionomers allowed us to separate the impacts of ion pair strength, multivalency, and reduced water uptake. We believe that these factors cause a more compressed hydrophilic domain and tortuous O 2 diffusion path, and a commensurate increase in R O2 . Lastly, we studied the impact of Co 2+ on an operating PEMFC and found an increase in R O2 consistent with the results of our isolated membrane tests.
Emissions in short-gated ns/ps/fs-LIBS for fuel-to-air ratio measurements in methane-air flames
A study of short-gated 10 nanosecond (ns), 100 picosecond (ps), and 100 femtosecond (fs) laser induced breakdown spectroscopy (LIBS) was conducted for fuel-to-air ratio (FAR) measurements in an atmospheric Hencken flame. The intent of the work is to understand which emission lines are available near the optical range in each pulse width regime and which emission ratios may be favorable for generating equivalence ratio calibration curves. The emission spectra in the range of 550–800 nm for ns-LIBS and ps-LIBS are mostly similar with slightly elevated atomic oxygen lines by ps-LIBS. Spectra from fs-LIBS show the lowest continuum background and prominent individual atomic lines, though have significantly weaker ionic emission from nitrogen. A qualitative explanation based on assumed local thermodynamic equilibrium and electron temperatures calculated by the N I I ( 565 n m ) and N I I ( 594 n m ) emissions is presented. In studying line emission ratios for FAR calculation, it is found that H α <#comment/> ( 656 n m ) / N I I ( 568 n m ) is best for FAR measurements with ns-LIBS and remains viable for ps-LIBS, while H α <#comment/> ( 656 n m ) / O I ( 777 n m ) is optimal for the ps-LIBS and fs-LIBS cases. Due to low continuum background and short time delay for spectra collection, fs-LIBS is very promising for high-speed FAR measurements using short-gated LIBS.
Waste-to-Fuel: A Case Study of Converting Food Waste to Renewable Natural Gas as a Transportation Fuel
This case study explores the production and use of renewable compressed natural gas (R-CNG)—derived from the anaerobic digestion (AD) of organic waste—to fuel heavy-duty refuse trucks and other natural gas vehicles in Sacramento, California.
Employment Effects of Hydrogen and Fuel Cells: Phase 1 Report, Fuel Cell Electric Vehicles
This report describes employment impacts associated with the manufacture, distribution and sale (MDS) of light-duty fuel cell electric vehicles (FCEVs) under a mid-range scenario of market development and uptake. Termed “gross” employment, these estimates include direct and indirect, full-time and part-time jobs associated with manufacturing, distributing and selling FCEVs, but not the consequent reduction in employment resulting from reduced demand for conventional vehicles (i.e., displaced employment). The latter estimates are included in a forthcoming technical memorandum documenting Phase 2 of this study.
Reference Fuel Development for NonAluminum Spent Nuclear Fuel Management
Background – The L Area Facility was initially constructed as a nuclear reactor for nuclear material production in the 1950s – The reactor was shut down in the late 1980s: in the 1990s the mission changed to storing nuclear material • Current Mission – L Area provides for the safe receipt, storage, handling, and shipping of spent nuclear fuel (SNF) and other nuclear materials – Received more than 47,000 SNF assemblies since 1964 from power and research reactors (domestic and foreign)
Resilient clamp holds fuel cell stack through resilient clamp holds fuel cell stack through thermal cycle
Resilient clamping device holds a stack of fuel cells during thermal expansion and contraction periods. The clamp has torsion bar action which maintains seal integrity over a wide stress range.
Calculation of fuel loss from vented nuclear fuel elements for space power reactors
Rate of loss of uranium dioxide or uranium mononitride from vented nuclear fuel element
Effect of fuel distribution and flame stabilization techniques on combustion stability limits for swirl-can combustor modules burning ASTM-A1 fuel
Effect of fuel distribution and flame stabilization techniques on combustion stability limits for swirl-can combustor modules
Design study of a high fuel fraction, externally-fueled thermionic diode suitable for in-pile testing
Engineering design of high fuel fraction diode for in-pile testing and evaluation of components under typical thermal stress conditions
Heat transfer correlations for kerosene fuels and mixtures and physical properties for Jet A fuel
Heat transfer correlations are reported for conventional Jet A fuel for both laminar and turbulent flow in circular tubes. Correlations were developed for cooling in turbine engines, but have broader applications in petroleum and chemical processing, and other industrial applications.
Vehicle Design Evaluation Program (VDEP). A computer program for weight sizing, economic, performance and mission analysis of fuel-conservative aircraft, multibodied aircraft and large cargo aircraft using both JP and alternative fuels
The NASA Langley Research Center vehicle design evaluation program (VDEP-2) was expanded by (1) incorporating into the program a capability to conduct preliminary design studies on subsonic commercial transport type aircraft using both JP and such alternate fuels as hydrogen and methane;(2) incorporating an aircraft detailed mission and performance analysis capability; and (3) developing and incorporating an external loads analysis capability. The resulting computer program (VDEP-3) provides a preliminary design tool that enables the user to perform integrated sizing, structural analysis, and cost studies on subsonic commercial transport aircraft. Both versions of the VDEP-3 Program which are designated preliminary Analysis VDEP-3 and detailed Analysis VDEP utilize the same vehicle sizing subprogram which includes a detailed mission analysis capability, as well as a geometry and weight analysis for multibodied configurations.
Orbiter fuel cell performance constraints. STS/OPS Pratt Whitney fuel cells. Operating limits for mission planning
The orbiter fuel cell powerplant (FCP) performance constraints listed in the Shuttle Operational Data Book (SODB) were analyzed using the shuttle environmental control requirements evaluation tool. The effects of FCP lifetime, coolant loops, and FCP voltage output were considered. Results indicate that the FCP limits defined in the SODB are not valid.