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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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Drought-induced changes in nitrogen partitioning between cyanide and nitrate in leaves and stems of sorghum grown at elevated CO2 are age dependent
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A reaction mechanism for ozone dissociation and reaction with hydrogen at elevated temperature
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Laminar flame speed measurements of a gasoline surrogate and its mixtures with ethanol at elevated pressure and temperature
Laminar Flame speed measurements of a gasoline surrogate and mixtures of it with ethanol were conducted using a heated, constant-volume vessel. A spherical propagating flame was observed using a high-speed camera, and laminar flame speed was determined therefrom. Here, the gasoline surrogate, which serves as the baseline for the current study, consisted of four components, namely, iso-octane, n-heptane, toluene, and 1-hexene. Different mixtures of the gasoline surrogate and ethanol were studied, governed by the ethanol percentage in the mixture. That is, E0, E30, E50, and E85 mixtures represent 0%, 30%, 50%, and 85% ethanol in the gasoline surrogate mixture by liquid volume, respectively. Initial temperatures of 335, 359, and 408 K and initial pressures of 1 and 3 bar were investigated. The findings of this study are compared to results in the literature, which show good agreement for E0 but some deviation for the E30 blend. In general, the study showed an increase in laminar flame speed as the ethanol percentage increases in the mixture. Similarly, increasing the initial temperature with fixed ethanol percentage resulted in an increase in laminar flame speed, as expected. In contrast, increasing the initial pressure with fixed Ethanol percentage showed a decrease in laminar flame speed. Finally, the results are compared to an existing chemical kinetics model designed for ethanol and gasoline. Although agreement between the model and data is reasonable and mostly within about 10%, some improvement to the kinetics model is needed to uniformly lower the calculated flame speeds.
An experimental study of the solubility and speciation of tantalum in fluoride-bearing aqueous solutions at elevated temperature
Here, the solubility of Ta 2 O 5 (solid) and the speciation of tantalum in HF-bearing aqueous solutions have been determined at temperatures of 100-250 °C and vapour-saturated water pressure. Tantalum is transported as the species Ta(OH) 5 0 at low HF concentration and pH ~1-3. At higher HF concentration, tantalum mobility is controlled by the species TaF 3 (OH) 3 - and TaF 5 ; the presence of TaF 5 0 is only evident at ≤150 °C. Equilibrium constants range from -17.4 ± 0.45 to -16.4 ± 0.12 for the formation of Ta(OH) 5 from crystalline Ta 2 O 5 and from -8.24 ± 0.64 to -8.55 ± 0.68 for the formation of TaF 3 (OH) 3 - at 100 and 250 °C, respectively. For TaF 5 0 , they were determined to be 0.13 at 100 °C and -0.35 at 150 °C.
GeoChip as a metagenomics tool to analyze the microbial gene diversity along an elevation gradient
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Experimental CO2 interactions with fractured Utica and Marcellus Shale samples at elevated pressure
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Free swelling behavior of MX80 bentonite under elevated temperatures up to 200 °C
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Factors associated with longer delays in reperfusion in ST-segment elevation myocardial infarction
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Impact of CO2 injection on wettability of coal at elevated pressure and temperature
Injection of carbon dioxide (CO 2 ) into coal seams has been demonstrated as an effective technology for enhanced methane recovery and CO 2 storage. However, the impacts of the geochemical reactions between CO 2 and coal on the wettability of coal pore surfaces, which influences immiscible multiphase displacement, are not yet well understood. We studied wettability alterations of coal surfaces resulting from reactions with gas, liquid and supercritical (sc)CO 2 under varied pressure (1–141 bar) and temperatures (˜25 - 60 °C) through measuring static and dynamic contact angles with anthracite coal plates. We found that reactions with gas CO 2 only slightly changed the wettability of coal surfaces from water-wet to intermediate-wet with static contact angles from ˜60° to 70°-90°. However, reactions with liquid and scCO 2 altered the coal surfaces to strongly CO 2 -wet, with the contact angles up to 115-180°. We also found that both static and dynamic contact angles increase significantly with increasing pressure. Temperature affects the contact angles reversely especially under supercritical pressure conditions. These relationships of contact angles with pressure and temperature may be explained by the CO 2 density dependence on pressure and temperature.