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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Removal of trace gases can both increase and decrease cloud droplet formation

Aerosols consist of liquid or solid particles dispersed in a gas. Aerosol measurements generally rely on drying the particles before quantifying their physicochemical properties. This drying can potentially remove semivolatile compounds from the particles. Here, we show size-resolved cloud condensation nuclei (CCN) measurements quantifying the hygroscopicity parameter in the presence and absence of a denuder. The denuder efficiently removed alkanes and weakly functionalized acids, aldehydes, and alcohols with fewer than 10 carbon atoms from the gas phase. Denuding organic compounds perturbed the CCN-derived hygroscopicity parameter by up to 50%. Denuding either rendered the particles more or less CCN active, and the direction of the effect depended on sample relative humidity and trace gas concentration. The effect was weakest in early spring and strongest in late spring and summer. The measurements demonstrate an unexpectedly strong coupling between the particle and gas phase, influencing CCN activity through either volatilization or surface adsorption, or both.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Dancing Droplets on a Defect Line [Poster]

Liquid crystalline (LC) phases are made up of molecules or other small units that organize into mesoscale assemblies. Their order resembles that of crystalline solids, but since the molecules have some freedom to move position and direction, these assemblies also behave like liquids. Thus, highly birefringent and responsive phases with many defect (or disclination) lines can emerge. These ever fluctuating lines indicate regions of the LC where the position of the molecules disrupt the local rotational symmetry within the phase.

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

Investigation of Scanning Droplet Cell Technology for Electrochemical Deposition of Custom Three-Dimensional Alloys

The goal of this project was to assess the feasibility of a new method of electroplating, which we have termed “electroprinting”, for fabricating millimeter to centimeter metal parts with full density, and eventually, with bespoke 3D internal density patterns. Alloys, gradients and varying density is beyond the scope of this work, and efforts were focused on developing the technology to be capable of printing solid parts, beyond the lines and columns previously reported in the literature. Enabling this technology would expand the design space possible for the WPD program, allowing for smooth and complex density gradients in parts rather than discrete density steps between multilayers. We successfully designed and built an electroprinting apparatus, capable of printing copper in customizable 1-D patterns, which can be printed in stacked layers to form 3D parts. We successfully characterized the flat printed patterns, however, have encountered difficulty in characterizing multilayer prints. We have partially addressed the feasibility question, by developing the method for electroprinting 3D parts, however, some questions about the internal porosity and density of these parts still remain.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Searching for Parton Energy Loss in Quark-Gluon Plasma Droplets (Technical Report)

This technical report summarizes the main accomplishments of the research performed under the U.S. Department of Energy (DOE) Office of Science, Early Career Award (ECA), grant number DE-SC0018117, from 9/1/2017 to 8/31/2022, with Prof. Dennis Perepelitsa as the single PI. The grant proposal was to investigate the quark-gluon plasma (QGP) created in ultrarelativistic collisions of large nuclei with the ATLAS experiment at the Large Hadron Collider (LHC) and to prepare for this physics with the sPHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). In particular, the focus was on QGP regions of different sizes and shapes, including the tradtional “large” collision systems such as Pb+Pb as well as small collision systems such as p+Pb, where there has been evidence of QGP “flow” but not yet the accompanying energy loss from hard-scattered partons traversing the QGP medium. Additionally, a particular tool was the use of photon+jet events, where the photon is unaffected by the QGP and thus serves as the “control” while the jet (the result of parton fragmentation) is the “probe” of the QGP. The research was successfully carried out, resulting in over ten publications of experimental measurements in peer-reviewed journals, and the significant training of junior scientists.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Large Eddy Simulation and Analysis of Truck Generated Droplet Spray Transport at Bridges

Weathering steel is a particular type of steel that develops a higher level of atmospheric corrosion protection than non-weathering grades of steel. While uncoated weathering steels have the appearance of being “rusted”, there are many forms of ferric oxyhydroxides (aka. rust) that can form on steel. The predominant ferric oxyhydroxide that gives uncoated weathering steel its tightly adherent patina is goethite. The atmospheric corrosion protection comes from alloying, primarily with a copper composition greater than 0.20 percent and also small amounts of chrome, nickel, and silicon. Bare atmospheric corrosion resistant steels have been recognized as far back as 1905 with very early editions of the American Society for Testing and Materials (ASTM) A 7 “Standard Specification for Steel for Bridges and Buildings” [1]. Uncoated weathering steel (UWS) is the lowest cost corrosion protection system possible for a steel bridge based on the first cost. Provided the UWS is used in an optimal environment that allows the protective patina to form, UWS also provides the lowest life cycle cost. The protective patina on UWS does not form or degrades in continuously damp conditions, forming a higher proportion of lepidocrocite, or in the presence of a concentration of chlorine ions that is too high, forming a higher proportion of akageneite.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Cloud Water Chemistry and Aerosol Processing: Assessing the Hydroxyl Radical Burst in Newly Formed Cloud Droplets (Field Campaign Report)

Aerosol particles are tiny liquid or solid particles in the atmosphere, ranging in size from a few nanometers to several micrometers in diameter. Aerosol-cloud interactions are the most uncertain aspect of the climate system, and models routinely underpredict aerosol particle formation. Clouds are well known to alter aerosol size, chemical composition, and radiative properties, but the processes are poorly characterized. Organics and sulfates are the most abundant materials in particles, and for each of these there are significant gaps in the understanding of the role of clouds in their formation and/or aging. Many of the cloud processes are driven by aqueous chemistry that depends on hydroxyl (OH) radicals, the subject of this project.

54 ENVIRONMENTAL SCIENCES↗