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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

Desert Research and Technology Studies 2008 Report

During the last two weeks of October 2008, the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) Advanced Extravehicular Activity (AEVA) team led the field test portion of the 2008 Desert Research and Technology Studies (D-RATS) near Flagstaff, AZ. The Desert RATS field test activity is the year-long culmination of various individual science and advanced engineering discipline areas technology and operations development efforts into a coordinated field test demonstration under representative (analog) planetary surface terrain conditions. The 2008 Desert RATS was the eleventh RATS field test and was the most focused and successful test to date with participants from six NASA field centers, three research organizations, one university, and one other government agency. The main test objective was to collect Unpressurized Rover (UPR) and Lunar Electric Rover (LER) engineering performance and human factors metrics while under extended periods of representative mission-based scenario test operations involving long drive distances, night-time driving, Extravehicular Activity (EVA) operations, and overnight campover periods. The test was extremely successful with all teams meeting the primary test objective. This paper summarizes Desert RATS 2008 test hardware, detailed test objectives, test operations, and test results.

Romig, Barbara↗
DOE OSTI2015

Annealing-free synthesis of carbonaceous Nb{sub 2}O{sub 5} microspheres by flame thermal method and enhanced photocatalytic activity for hydrogen evolution

Graphical abstract: Carbonaceous Nb{sub 2}O{sub 5} microspheres were firstly prepared by annealing-free flame thermal approach and its enhanced photocatalytic activity was demonstrated for hydrogen production. - Highlights: • Carbonaceous Nb{sub 2}O{sub 5} microspheres were prepared by annealing-free flame thermal approach in the first time. • Hydrolysis and incomplete combustion gave rise to Nb{sub 2}O{sub 5} incorporated with carbon. • Carbon species act as surface sensitizer to enhance photocatalytic activity. • It is possible to extend the strategy to develop various other metal oxides. - Abstract: An annealing-free synthesis of carbonaceous Nb{sub 2}O{sub 5} photocatalyst via a one-step flame assisted pyrolysis approach was proposed for the first time. Nearly amorphous carbonaceous Nb{sub 2}O{sub 5} microspheres were obtained directly through the facile and waste-free method. The presence of carbonate species was confirmed by means of EDS, XPS, BET and TEM. Both FT-IR and Raman analysis further revealed the existence form of carbon residuals for the resulted sample. UV–vis diffuse reflectance spectra showed the strong absorption of visible light and narrowed band gap for the carbon modified Nb{sub 2}O{sub 5}. On account of the vital role that carbon played in efficient electron-hole separation and light absorption, the hydrogen generation rate was 2.7 times that of the annealed and commercial Nb{sub 2}O{sub 5} samples. Further calcination can foster the crystallinity and expand specific surface area but lower the photocatalytic performance of as-prepared Nb{sub 2}O{sub 5} because of the elimination of carbon species. This work provides a new strategy for the preparation of carbonaceous Nb{sub 2}O{sub 5} candidates with enhanced photocatalytic activity.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Addressing spreading pressure dependence of real adsorbed solution theory with generalized Langmuir isotherm

This work addresses spreading pressure dependence of Real Adsorbed Solution Theory (RAST) for mixed-gas adsorption equilibria using generalized Langmuir (gL) isotherm. Considering vacant sites as an integral part of competitive multicomponent adsorption on a constant adsorbent surface area, the gL isotherm properly accounts for surface heterogeneity and loading, adsorbate composition, and temperature dependence. We show the spreading pressure dependence of adsorbate activity coefficient expression in the RAST framework can be generated from the gL isotherm. The procedure is illustrated with a spreading pressure dependent adsorption Nonrandom Furthermore, two-Liquid activity coefficient model, and the results are validated for ten binary mixed-gas adsorption equilibria systems including two highly nonideal azeotropic systems.

42 ENGINEERING↗
DOE OSTI2018

Self-assembly synthesis of BiVO4/Polydopamine/g-C3N4 with enhanced visible light photocatalytic performance

Highlights: • BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4} was synthesized via simple self-assembly at the room temperature. • PDA has a strong binding affinity to BiVO{sub 4} and g-C{sub 3}N{sub 4} to form BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4}. • BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4} exhibits good stability and reusability in the photocatalytic reaction of glyphosate. • The enhanced activity of BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4} is mainly attributed to the increased charge separation. - Abstract: BiVO{sub 4}/PDA(Polydopamine)/g-C{sub 3}N{sub 4} was synthesized by facile ultrasonic dispersion and self-assembly at the room temperature, and monoclinic BiVO{sub 4} was embedded on PDA/g-C{sub 3}N{sub 4} sheet, which PDA was first formed in situ on the surface of g-C{sub 3}N{sub 4} via self-polymerization of dopamine. The dependence of photocatalytic activity on the structural, electronic and optical properties of the BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4} nanostructure has been explored using XRD, XPS, TEM, SEM, DRS, PL, BET and photocurrent. The BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4} photocatalysts show higher activity of glyphosate degradation than BiVO{sub 4}, g-C{sub 3}N{sub 4} and BiVO{sub 4}/g-C{sub 3}N{sub 4} under visible light irradiation. The enhanced activity of BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4} can be significantly attributed to the improved visible light absorption, enhanced specific surface area and increased charge separation. PDA has a strong and irreversible binding ability onto BiVO{sub 4} and g-C{sub 3}N{sub 4} to form BiVO{sub 4}/PDA/g-C{sub 3}N{sub 4}. This simple method at the room temperature is promising for the synthesis of high performance composite photocatalysts for different applications, such as pollutant degradation, photocatalytic splitting water, etc.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Adsorption and capacitive regeneration of nitrate using inverted capacitive deionization with surfactant functionalized carbon electrodes [Nitrate removal using inverted capacitive deionization with surfactant-treated electrodes]

Nitrate is a pollutant present in groundwater worldwide. Several techniques are available to remove nitrate from water, but they are difficult to automate in remote settings or require chemicals for treatment for regeneration. Here, we demonstrate the use of two surfactant-treated high surface area porous electrodes for passive adsorption of nitrate followed by electrical regeneration. In order to generate the surface charge driving adsorption, we functionalized the active electrode (cathode) and capacitive counter electrode (anode) with cetrimonium bromide (CTAB) and sodium dodecyl benzene sulphonate (SDBS), respectively. We find voltage applied during regeneration is directly proportional to the subsequent available adsorption capacity at short circuit. In a recent preliminary work, we used a Faradaic counter electrode, and here, we compare both studies in terms of energy-normalized adsorbed salt (ENAS)—a measure of energy efficiency—and average salt adsorption rate (ASAR). Lastly, we show that capacitive counter electrode used in this work increases ENAS by two orders of magnitude, while maintaining a similar ASAR.

42 ENGINEERING↗
DOE OSTI2024

Nanobubble Formation and Coverage during High Current Density Alkaline Water Electrolysis

Gas bubbles are a necessary byproduct of water electrolysis whereby hydrogen and oxygen are produced from water. These attached gases reduce the electrode’s active area, which necessitates a deep understanding of the bubble life cycle starting from nanobubbles. Synchronized with the electrochemistry, the time evolution of the surface nanobubble size and coverage is resolved using grazing incidence small-angle X-ray scattering (GISAXS) and correlated with optical microscopy and theoretical calculations to show that a significant portion of the surface is covered in nanobubbles after larger micron-sized bubbles are observed. Further, these nanobubbles increase in number and decrease in size, toward 2 nm diameter, with the charge passed. The trend in size and number is consistent with an increase in supersaturation, which reduces the nascent bubble size. Altogether, this study suggests a significant portion of the surface contains nanobubbles and that strategies to reduce the dissolved hydrogen would be effective at reducing the nanobubble surface coverage.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Efficient monolithic all-perovskite tandem solar modules with small cell-to-module derate

All-perovskite tandem solar modules are promising to reduce the cost of photovoltaic systems with their high efficiency and solution fabrication, but their sensitivity to air still imposes a great challenge. Here a hot gas-assisted blading method is developed to accelerate the perovskite solidification, forming compact and thick narrow bandgap (NBG) perovskite films. Adding a reduction agent into NBG films followed by a short period of air exposure and a post-fabrication storage surprisingly increases carrier recombination lifetime and enables laser scribing in ambient conditions without obvious loss of device performance. This combination suppresses tin and iodide oxidation and forms a thin SnO 2 layer on the NBG film surface. Monolithic all-perovskite tandem solar modules showed a champion efficiency of 21.6% with a 14.3 cm 2 aperture area, corresponding to an active area efficiency of 23.0%. Lastly, the very small cell-to-module derate of 6.5% demonstrates the advantage of a tandem monolithic structure for solar modules.

14 SOLAR ENERGY↗
DOE OSTI2014

Jumping-droplet electrostatic energy harvesting

Micro- and nanoscale wetting phenomena have been an active area of research due to its potential for improving engineered system performance involving phase change. With the recent advancements in micro/nanofabrication techniques, structured surfaces can now be designed to allow condensing coalesced droplets to spontaneously jump off the surface due to the conversion of excess surface energy into kinetic energy. In addition to being removed at micrometric length scales (~10 μm), jumping water droplets also attain a positive electrostatic charge (~10–100 fC) from the hydrophobic coating/condensate interaction. In this work, we take advantage of this droplet charging to demonstrate jumping-droplet electrostatic energy harvesting. The charged droplets jump between superhydrophobic copper oxide and hydrophilic copper surfaces to create an electrostatic potential and generate power during formation of atmospheric dew. We demonstrated power densities of ~15 pW/cm 2 , which, in the near term, can be improved to ~1 $μ$W/cm 2 . This work demonstrates a surface engineered platform that promises to be low cost and scalable for atmospheric energy harvesting and electric power generation.

42 ENGINEERING↗
DOE OSTI2014

Co-Pt core-shell nanostructured catalyst prepared by selective chemical vapor pulse deposition of Pt on Co as a cathode in polymer electrolyte fuel cells

A new type of PtCo/C catalyst for use as a cathode in polymer electrolyte fuel cells was prepared by selective chemical vapor pulse deposition (CVPD) of Pt on the surface of Co. The activity of the prepared catalyst for oxygen reduction was higher than that of a catalyst prepared by sequential impregnation (IMP) with the two metallic components. This catalytic activity difference occurs because the former catalyst has smaller Pt crystallites that produce stronger Pt-Co interactions and have a larger Pt surface area. Consequently, the CVPD catalyst has a great number of Co particles that are in close contact with the added Pt. The Pt surface was also electronically modified by interactions with Co, which were stronger in the CVPD catalyst than in the IMP catalyst, as indicated by X-ray diffraction, X-ray photoemission spectroscopy, and cyclic voltammetry measurements of the catalysts.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Vitrification Testing of HLW with High Phosphate

Projections of the number of high level waste (HLW) canisters to be produced in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) (e.g., [1]) are based upon the inventory of the tank wastes, the anticipated performance of the sludge treatment processes, and current understanding of the capability of the borosilicate glass waste form. The WTP HLW melter design, unlike earlier Department of Energy (DOE) melter designs, incorporates a glass bubbler system. The bubblers create active glass pool mixing and thereby improve heat and mass transfer and glass melting rate. The WTP HLW melters each have a glass surface area of 3.75 m 2 and depth of ~1.1 m. The two melters in the HLW facility together are designed to produce up to 7.5 MT of glass per day at 100% availability. Further increases in HLW waste processing rates can potentially be achieved by optimization of the feed and glass formulations, increasing the melter operating temperature above 1150⁰C, and by increasing the waste loading in the glass product. Increasing the waste loading also has the added benefit of decreasing the number of canisters for storage.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1975

Comparison of flight measurements with predictions from aeroelastic models in the NASA Langley Transonic Dynamics Tunnel

The NASA Langley Transonic Dynamics Tunnel, which has a variable density, Freon-12 (or air) test medium, was designed to study the dynamics and aeroelastic problems of aerospace vehicles. During the operation of this facility there have been various opportunities to compare wind tunnel and flight test results. Some of these opportunities arise from routine flight checks of the prototype, others from carefully designed comparative wind tunnel and flight experiments. A collection of data obtained from various published and unpublished sources is presented. The topics covered are: gust and buffet response, control surface effectiveness, flutter, and active control of aeroelastic effects. Some benefits and shortcomings of Freon-12 as a test medium are also discussed. Although areas of uncertainty are evident and there is a continuing need for improvements in model simulation and testing techniques, the results presented herein indicate that predictions from aeroelastic model tests are, in general, substantiated by full-scale flight tests.

Reed, W. H., III↗
NASA NTRS1976

Comparisons of flight measurements with predictions from aeroelastic models in the NASA Langley Transonic Dynamics Tunnel

The NASA Langley Transonic Dynamics Tunnel, which has a variable density Freon-12 (or air) test medium, was designed for the study of dynamics and aeroelastic problems of aerospace vehicles. During the 15 years of operation of this facility there have been various opportunities to compare wind tunnel and flight test results. Some of these opportunities arise from routine flight checks of the prototype, others from carefully designed comparative wind tunnel and flight experiments. Data obtained from various sources is presented. The topics covered are: gust and buffet response, control surface effectiveness, flutter, and active control of aeroelastic effects. Some benefits and shortcomings of Freon-12 as a test medium are also discussed. Although areas of uncertainly are evident and there is a continuing need for improvements in model simulation and testing techniques, the results indicate that predictions from aeroelastic model tests are, in general, substantiated by full scale flight tests.

Reed, W. H., III↗
NASA NTRS1976

Correlation with flight of some aeroelastic model studies in the NASA Langley transonic dynamics tunnel

The NASA Langley transonic dynamics tunnel, which has a variable density Freon-12 (or air) test medium, was designed specifically for the study of dynamics and aeroelastic problems of aerospace vehicles. During the 15 years of operation of this facility, there have been various opportunities to compare wind tunnel and flight test results. Some of these opportunities arise from routine flight checks of the prototypes; others, from carefully designed comparative wind-tunnel and flight experiments. Such data obtained from various published and unpublished sources are presented. The topics covered are: gust and buffet response, control surface effectiveness, flutter, and active control of aeroelastic effects. Some benefits and shortcomings of Freon-12 as a test medium are also discussed. Although areas of uncertainty are evident and there is a continuing need for improvements in model simulation and testing techniques, the results presented indicate that predictions from aeroelastic model tests are, in general, substantiated by full scale flight tests.

Reed, W. H., III↗
NASA NTRS1981

Discrimination of unique biological communities in the Mississippi lignite belt

Small scale hardcopy LANDSAT prints were manually interpreted and color infrared aerial photography was obtained in an effort to identify and map large contiguous areas of old growth hardwood stands within Mississippi's lignite belt which do not exhibit signs of recent disturbance by agriculture, grazing, timber harvesting, fire, or any natural catastrophe, and which may, therefore, contain unique or historical ecological habitat types. An information system using land cover classes derived from digital LANDSAT data and containing information on geology, hydrology, soils, and cultural activities was developed. Using computer-assisted land cover classifications, all hardwood remnants in the study area which are subject to possible disturbance from surface mining were determined. Twelve rare plants were also identified by botanists.

Miller, W. F.↗
DOE OSTI2015

Photocatalytic property and structural stability of CuAl-based layered double hydroxides

Three types of CuMAl layered double hydroxides (LDHs, M=Mg, Zn, Ni) were successfully synthesized by coprecipitation. Powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES) and UV–Vis diffuse reflectance spectrum (UV–vis) were used to confirm the formation of as-synthesized solids with good crystal structure. The photocatalytic activity of those LDH materials for CO{sub 2} reduction under visible light was investigated. The experimental results show that CuNiAl-LDHs with narrowest band gap and largest surface areas behave highest efficiency for methanol generation under visible light compared with CuMgAl-LDHs and CuZnAl-LDHs. The CuNiAL-LDH showed high yield for methanol production i.e. 0.210 mmol/g h, which was high efficient. In addition, the influence of the different M{sup 2+} on the structures and stability of the CuMAl-LDHs was also investigated by analyzing the geometric parameters, electronic arrangement, charge populations, hydrogen-bonding, and binding energies by density functional theory (DFT) analysis. The theoretical calculation results show that the chemical stability of LDH materials followed the order of CuMgAl-LDHs>CuZnAl-LDHs>CuNiAl-LDHs, which is just opposite with the photocatalytic activity and band gaps of three materials. - Graphical abstract: The host–guest calculation models and XRD patterns of CuMAl-LDHs: CuMgAl-LDHs (a), CuZnAl-LDHs (b) and CuNiAl-LDHs (c). - Highlights: • Three types of CuMAl layered double hydroxides (LDHs, M=Mg, Zn, Ni) has been synthesized. • CuMgNi shows narrower band gap and more excellent textural properties than other LDHs. • The band gap: CuMgAl<CuZnAl<CuNiAl based on result from UV–vis analysis. • CuMgAl shows the highest stability and lowest photocatalytic activity, while CuNiAl just opposite.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Mesoporous MFe{sub 2}O{sub 4} (M = Mn, Co, and Ni) for anode materials of lithium-ion batteries: Synthesis and electrochemical properties

Highlights: • MFe{sub 2}O{sub 4} (M = Mn, Co, and Ni) are synthesized by a template-free hydrothermal method. • The mesoporous morphology is formed by self-assembly of crystal nucleus. • The mesporous MnFe{sub 2}O{sub 4} have the active phase and the synergy for Li-ion storage. - Abstract: The MFe{sub 2}O{sub 4} (M = Mn, Co, and Ni) mesoporous spheres with an average diameter of 250 nm were synthesized through a template-free hydrothermal method. The mesoporous MnFe{sub 2}O{sub 4} with a large surface area of 87.5 m{sup 2}/g and an average pore size of 27.52 nm were obtained. As the anode materials for Li-ion batteries, the mesoporous MnFe{sub 2}O{sub 4} exhibits excellent initial charge and discharge capacities of 1010 and 642.5 mA h/g. After 50 cycles, the discharge capacity could still remain at 379 mA h/g. The results showed that the active phase and the synergy between different metal oxides greatly improved the electrochemical performance, and the mesoporous composite could stabilize the structure of the electrodes.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Dendritic Assembly of Gold Nanoparticles during Fuel-Forming Electrocatalysis

We report on the dendritic assembly of alkanethiol-capped gold nanoparticles on a glassy carbon support during electrochemical reduction of protons and CO 2 . We discovered that the primary mechanism by which surfactant-ligated gold nanoparticles lose surface area is by taking a random walk along the support, colliding with their neighbors, and fusing to form dendrites, a type of fractal aggregate. A random walk model reproduces the fractal dimensionality of the dendrites observed experimentally. The rate at which the dendrites form is strongly dependent on the solubility of the surfactant in the electrochemical double layer under the conditions of electrolysis. Since alkanethiolate surfactants reductively desorb at potentials close to the onset of CO 2 reduction, they do not poison the catalytic activity of the gold nanoparticles. While catalyst mobility is typically thought to be limited for room-temperature electrochemistry, our results reflect that nanoparticle mobility is significant under conditions at which they electrochemically catalyze gas evolution, even in the presence of a high surface area carbon and binder. A careful understanding of the electrolyte- and polarization-dependent nanoparticle aggregation kinetics informs strategies for maintaining catalyst dispersion during fuel-forming electrocatalysis.

dendrons↗