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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

What are the Starting Points? Evaluating Base-Year Assumptions in the Asian Modeling Exercise

A common feature of model inter-comparison efforts is that the base year numbers for important parameters such as population and GDP can differ substantially across models. This paper explores the sources and implications of this variation in Asian countries across the models participating in the Asian Modeling Exercise (AME). Because the models do not all have a common base year, each team was required to provide data for 2005 for comparison purposes. This paper compares the year 2005 information for different models, noting the degree of variation in important parameters, including population, GDP, primary energy, electricity, and CO2 emissions. It then explores the difference in these key parameters across different sources of base-year information. The analysis confirms that the sources provide different values for many key parameters. This variation across data sources and additional reasons why models might provide different base-year numbers, including differences in regional definitions, differences in model base year, and differences in GDP transformation methodologies, are then discussed in the context of the AME scenarios. Finally, the paper explores the implications of base-year variation on long-term model results.

base year data↗
DOE OSTI2018

Distribution and predictors of urinary concentrations of phthalate metabolites and phenols among pregnant women in the Healthy Start Study

Highlights: • Urinary phthalate metabolites, phenols and parabens were detected during pregnancy. • Concentrations differed by maternal sociodemographic characteristics. • Results did not provide strong evidence for specific dietary sources of exposure. Phthalates and phenols are suspected endocrine disrupting chemicals that may adversely impact fetal outcomes following in utero exposure. Understanding predictors of exposure to phthalates and phenols during the prenatal period is important.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

A Prospective Randomized Trial of the Influence of Music on Anxiety in Patients Starting Radiation Therapy for Cancer

One of the most downloaded articles in 2017 from the International Journal of Radiation Oncology, Biology, and Physics was a study suggesting that music therapy during radiation therapy (RT) simulation substantially reduces anxiety. To further evaluate the potential of music's clinical efficacy in the context of radiation therapy, we conducted a randomized trial evaluating the influence of genre-based music chosen by the study participant on anxiety during the first RT treatment session with a method that is applicable to routine clinical practice.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Phase evolution during reactive flash sintering of Li 6.25 Al 0.25 La 3 Zr 2 O 12 starting from a chemically prepared powder

Here, reactive flash sintering (RFS) of a chemically prepared multiphase precursor powder was performed to fabricate Li 6.25 Al 0.25 La 3 Zr 2 O 12 (Al-LLZO) ceramics. This approach allowed for obtaining single-phase dense samples in a remarkably short processing time of 30 s, at a furnace temperature of 600 °C, with an electric field of 50 V cm -1 and a current limit of 150 mA mm -2 . The ceramics display high bulk conductivity of 0.18 mS cm -1 at room temperature. Furthermore, phase evolution is studied by in-situ X-ray diffraction during: i) conventional heating and ii) RFS under current rate mode. As expected, the intermediate phases progressively dissolved into the Al-LLZO matrix by conventional heating. On the other hand, RFS promoted the growth of the intermediate La 2 Zr 2 O 7 , an effect that was overcome by the thermally driven formation of Al-LLZO at higher temperatures. The observed different reaction pathway suggests that RFS can be used for stabilizing phases that are not thermodynamically favored upon conventional heating.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Microwave-assisted hydrothermal synthesis of zinc oxide particles starting from chloride precursor

Graphical abstract: Schematic of the mechanism for ZnO nanoparticles obtained by the calcination. Highlights: Black-Right-Pointing-Pointer Nanocrystalline ZnO particles were successfully prepared by a microwave-assisted method. Black-Right-Pointing-Pointer Sponge-like morphology of ZnO change to a net-like structure after thermal treatment. Black-Right-Pointing-Pointer The PL spectra exhibited a nearband-edge emission at 393 nm. -- Abstract: Zinc oxide (ZnO) was synthesized using a microwave assisted hydrothermal (MAH) process based on chloride/urea/water solution and under 800 W irradiation for 5 min. In the bath, Zn{sup 2+} ions reacted with the complex carbonate and hydroxide ions to form zinc carbonate hydroxide hydrate (Zn{sub 4}CO{sub 3}(OH){sub 6}{center_dot}H{sub 2}O), and the conversion from Zn{sub 4}CO{sub 3}(OH){sub 6}{center_dot}H{sub 2}O to ZnO was synchronously achieved by a MAH process. The as-prepared ZnO has a sponge-like morphology. However, the initial sponge-like morphology of ZnO could change to a net-like structure after thermal treatment, and compact nano-scale ZnO particles were finally obtained when the period of thermal treatment increased to 30 min. Pure ZnO nanoparticles was obtained from calcination of loose sponge-like ZnO particles at 500 Degree-Sign C. The analysis of optical properties of these ZnO nanoparticles showed that the intensity of 393 nm emission increased with the calcination temperature because the defects were reduced and the crystallinity was improved.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Up up down down left right left right B A Start for the catalytic hackers of programmable materials

Catalysts have advanced over the last century to accelerate and control reactions based on static active sites. More effective catalysis can be achieved using catalysts that change with time over the course of a reaction, providing a dynamic free energy landscape that is tailored to each step in the reaction sequence. Here, the catalyst is modulated via an input program that directs the surface to change physically or electronically with time, providing information regarding the extent and duration of change optimized for specific combinations of chemistry and programmable catalyst surfaces. While in its infancy, programmable catalysis is advancing with parallel efforts to establish fundamental principles of dynamic catalysts, design of programmable materials, and strategies to design input programs that will control catalysis for faster and more selective reactions.

catalyst↗
DOE OSTI2014

A synergistic biorefinery based on catalytic conversion of lignin prior to cellulose starting from lignocellulosic biomass

Current biomass utilization processes do not make use of lignin beyond its heat value. Here we report on a bimetallic Zn/Pd/C catalyst that converts lignin in intact lignocellulosic biomass directly into two methoxyphenol products, leaving behind the carbohydrates as a solid residue. Genetically modified poplar enhanced in syringyl (S) monomer content yields only a single product, dihydroeugenol. Lignin-derived methoxyphenols can be deoxygenated further to propylcyclohexane. In this work the leftover carbohydrate residue is hydrolyzed by cellulases to give glucose in 95% yield, which is comparable to lignin-free cellulose (solka floc). New conversion pathways to useful fuels and chemicals are proposed based on the efficient conversion of lignin into intact hydrocarbons.

09 BIOMASS FUELS↗
DOE OSTI2015

Topological insulator thin films starting from the amorphous phase-Bi{sub 2}Se{sub 3} as example

We present a new method to obtain topological insulator Bi{sub 2}Se{sub 3} thin films with a centimeter large lateral length. To produce amorphous Bi{sub 2}Se{sub 3} thin films, we have used a sequential flash-evaporation method at room temperature. Transmission electron microscopy has been used to verify that the prepared samples are in a pure amorphous state. During annealing, the samples transform into the rhombohedral Bi{sub 2}Se{sub 3} crystalline structure which was confirmed using X-ray diffraction and Raman spectroscopy. Resistance measurements of the amorphous films show the expected Mott variable range hopping conduction process with a high specific resistance compared to the one obtained in the crystalline phase (metallic behavior). We have measured the magnetoresistance and the Hall effect at different temperatures between 2 K and 275 K. At temperatures T ≲ 50 K and fields B ≲ 1 T, we observe weak anti-localization in the MR; the Hall measurements confirm the n-type character of the samples. All experimental results of our films are in quantitative agreement with results from samples prepared using more sophisticated methods.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2012

OBSERVATIONS FROM SDO, HINODE, AND STEREO OF A TWISTING AND WRITHING START TO A SOLAR-FILAMENT-ERUPTION CASCADE

We analyze data from SDO (AIA, HMI), Hinode (SOT, XRT, EIS), and STEREO (EUVI) of a solar eruption sequence of 2011 June 1 near 16:00 UT, with an emphasis on the early evolution toward eruption. Ultimately, the sequence consisted of three emission bursts and two filament ejections. SDO/AIA 304 A images show absorbing-material strands initially in close proximity which over {approx}20 minutes form a twisted structure, presumably a flux rope with {approx}10{sup 29} erg of free energy that triggers the resulting evolution. A jump in the filament/flux rope's displacement (average velocity {approx}20 km s{sup -1}) and the first burst of emission accompanies the flux-rope formation. After {approx}20 more minutes, the flux rope/filament kinks and writhes, followed by a semi-steady state where the flux rope/filament rises at ({approx}5 km s{sup -1}) for {approx}10 minutes. Then the writhed flux rope/filament again becomes MHD unstable and violently erupts, along with rapid (50 km s{sup -1}) ejection of the filament and the second burst of emission. That ejection removed a field that had been restraining a second filament, which subsequently erupts as the second filament ejection accompanied by the third (final) burst of emission. Magnetograms from SDO/HMI and Hinode/SOT, and other data, reveal several possible causes for initiating the flux-rope-building reconnection, but we are not able to say which is dominant. Our observations are consistent with magnetic reconnection initiating the first burst and the flux-rope formation, with MHD processes initiating the further dynamics. Both filament ejections are consistent with the standard model for solar eruptions.

79 ASTRONOMY AND ASTROPHYSICS↗