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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Reflections on Cyanobacterial Chromatic Acclimation: Exploring the Molecular Bases of Organismal Acclimation and Motivation for Rethinking the Promotion of Equity in STEM

Cyanobacteria are photosynthetic organisms that exhibit characteristic acclimation and developmental responses to dynamic changes in the external light environment. Photomorphogenesis is the tuning of cellular physiology, development, morphology, and metabolism in response to external light cues. The tuning of photosynthetic pigmentation, carbon fixation capacity, and cellular and filament morphologies to changes in the prevalent wavelengths and abundance of light have been investigated to understand the regulation and fitness implications of different aspects of cyanobacterial photomorphogenesis. Chromatic acclimation (CA) is the most common form of photomorphogenesis that has been explored in cyanobacteria. Multiple types of CA in cyanobacteria have been reported, and insights gained into the regulatory pathways and networks controlling some of these CA types. I examine the recent expansion of CA types that occur in nature and provide an overview of known regulatory factors involved in distinct aspects of cyanobacterial photomorphogenesis. Additionally, I explore lessons for cultivating success in scientific communities that can be drawn from a reflection on existing knowledge of and approaches to studying CA.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

SPRUCE: Shrub Leaf and Stem Functional Traits from 10-year Shrub Layer Biomass Harvests (August 2025)

This data set contains Leaf Mass Area (LMA), Specific Leaf Area (SLA), Leaf Area Index (LAI), and Huber value (Hv) measurements from the 10-year Shrub-layer Biomass harvests in the Spruce and Peatland Responses Under Environmental Change (SPRUCE) experiment in August 2025. The total ground-level cross-sectional sapwood area of Chamaedaphne calyculata (CHCA), Rhododendron groenlandicum (RHGR), and Vaccinium angustifolium (VAAN) were calculated for each of the three shrub-layer community survey plots located in each experimental enclosure. Representative current-year leaves were removed, scanned, dried, and weighed to derive SLA. Grab-samples for VAAN were used to calculate SLA when no biomass was harvested in the shrub-layer community plots. These SLA values were used to infer total one-sided leave surface area from the total species lead dry mass for calculation of LAI and Hv.

Birkebak, Joshua [ORNL] (ORCID:0009000955611494)↗
DOE OSTI2020

Grain boundary structure of two-dimensional tellurium revealed by 4D STEM

The recent realization of 2D tellurium (tellurene) has allowed scientists to demonstrate an air-stable monoelemental van der Waals material with remarkable potential for applications in electronics and optoelectronics. The chiral-chain structure of ultrathin Te allows controllable electronic and optical properties due to the non-monotonic carrier mobility and an increase in electronic band-gap as the thickness is reduced. Scalable and accurate production of 2D Te-based functional devices will require detailed knowledge of structural defects and strain field distributions that can be linked to transport properties.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Towards durable resistance to Septoria stem canker and leaf spot: A molecular understanding of resistance (Final Technical Report)

To identify, validate, and functionally characterize alleles that confer resistance to Septoria canker and leaf spot in Populus. The proposed research will elucidate a major mechanism of resistance to Sphaerulina musiva, the major limiting factor to plantations in eastern North America. Genome-wide association mapping, CRISPR/Cas9, and protein-protein assays will be used, enabling marker-aided breeding, reducing costs, and accelerating development of resistant varieties.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Record of Treatment for Concrete Preservation Work at TA-6-0037 Concrete Bowl, TA-08 Gun Site, TA-16-0518 Stem Wall, and TA-18 Battleship Bunkers (Historic Buildings Report)

This completion report documents concrete preservation work that occurred in Fiscal Years 2019 and 2020. Work took place at four sites (Technical Areas [TAs] -06, -08, -16, and -18) that hold Manhattan Project–era significance. Seven buildings and structures were included in the project scope, with concentrated assessments and treatment plans accomplished before the start of preservation activities. The attended buildings and structures represent eligible or included Manhattan Project National Historical Park resources. The stabilization of original fabric and the retention of integrity and significance remained paramount throughout all phases of this project.

42 ENGINEERING↗
DOE OSTI2020

Optimizing Sub-Sampled STEM Imaging for Beam Sensitive Materials and Dynamic Processes

The goal of this research is to quantify how sub-sampling and inpainting (broadly classified as methods in Artificial Intelligence) can be used to obtain the highest resolution images under any experimental conditions, and to use this to reproducibly control dynamic in-situ processes in gases and liquids on the nanoscale. As atomic diffusion under non-extreme conditions is typically in the sub-ms time domain, the ability to use this sub-sampling approach to reduce the effect of the electron beam and to speed-up the imaging process represents the optimum combination of spatial and temporal resolution achievable in a conventional microscope. This LDRD funding demonstrated the feasibility of imaging dynamics in complex energy systems using this methodology by establishing the optimum experimental sampling conditions (optimizing the number of pixels, speed, contrast and resolution) for each experiment. For in-situ liquid cell experiments this analysis shows that simply by distributing the same dose and dose rate maximally in space and time, the kinetics for radiolysis products can be modified significantly. The final stage of this work, i.e. the experimental demonstration of its use for nucleation and growth, was severely curtailed by issues with COVID19. However, all the experiments are designed and currently underway, with the goal to complete the final demonstration and publication as soon as safety concerns for laboratory access are met.

36 MATERIALS SCIENCE↗
DOE OSTI2019

PIE of Cycle 13 316SS Cladding Using Aberration Corrected STEM Image and Analys

Optical, SEM and TEM analysis confirmed the presence of moderate sensitization in the 20% cold worked 316SS after the iron aluminide coating was applied. The Cr depletion occurs on the grain boundaries between the closely spaced carbides, and at the interface between the carbides and matrix. Cr depletion varied from locally along the grain boundaries, in many cases showing levels down to 15 wt%, but a few isolated regions had depletion levels down to 12.5 wt%. Optical and SEM images taken from a weld heat affected zone revealed the recrystallization occurred after an end plug cap had been welded to the coated cladding. Irradiation did not affect the carbides in a noticeable manner, but radiation-induced segregation/depletion altered the Cr depletion profiles by removing the wide Cr depletion profile, and replacing it with a much deeper, more narrow profile. Cr levels were depleted to 8-10 wt%, Ni and Si were enriched to levels of 40 wt% and 12 wt% respectively. Substantial precipitation formed in the matrix, and on line dislocations in the matrix and on grain boundary dislocations. Voids were observed in the upper region of the TPBAR where the irradiation temperature exceeds 320C. The levels of Cr depletion and Ni/Si enrichment indicate a material in a state susceptible to irradiation assisted stress corrosion cracking.

316SS cladding↗
DOE OSTI2024

Visualization of lignification in flax stem cell walls with novel click-compatible monolignol analogs

As an essential part of plant cell walls, lignin provides mechanical support for plant growth, enhances water transport, and helps to defend against pathogens. As the most abundant natural aromatic-based renewable resource on earth, its biosynthesis has always been a research focus, and it is still currently under study. In this study, the p-coumaryl alcohol analog (H ALK ) and the coniferyl alcohol analog (G ALK ) containing an alkyne group at the ortho position were synthesized and applied to lignification in vivo and in vitro. The incorporation of these novel lignin monomers was observed via fluorescence imaging. It was found that the two monolignol analogs could be incorporated in dehydrogenated polymers (DHPs) in vitro and in flax cell walls in vivo. The results showed that as the cultivation time and precursor concentration varied, the deposition of H and G-type lignin exhibited differences in deposition mode. At the subcellular scale, the deposited lignin first appears in the cell corner and the middle lamella, and then gradually appears on the cell walls. Furthermore, lignin was also found in bast fiber. It was demonstrated that these new molecules could provide high-resolution localization of lignin during polymerization.

59 BASIC BIOLOGICAL SCIENCES↗