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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 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaAcIn2 by Materials Project

NaAcIn2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Na is bonded in a body-centered cubic geometry to eight equivalent In atoms. All Na–In bond lengths are 3.44 Å. Ac is bonded in a body-centered cubic geometry to eight equivalent In atoms. All Ac–In bond lengths are 3.44 Å. In is bonded in a body-centered cubic geometry to four equivalent Na and four equivalent Ac atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ac3Si by Materials Project

Ac3Si crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ac is bonded in a 4-coordinate geometry to four equivalent Si atoms. There are two shorter (3.42 Å) and two longer (3.80 Å) Ac–Si bond lengths. Si is bonded to twelve equivalent Ac atoms to form a mixture of distorted face and corner-sharing SiAc12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrAcIn2 by Materials Project

SrAcIn2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Sr is bonded in a body-centered cubic geometry to eight equivalent In atoms. All Sr–In bond lengths are 3.57 Å. Ac is bonded in a body-centered cubic geometry to eight equivalent In atoms. All Ac–In bond lengths are 3.57 Å. In is bonded in a body-centered cubic geometry to four equivalent Sr and four equivalent Ac atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ac3Cl by Materials Project

Ac3Cl is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ac is bonded in a distorted square co-planar geometry to four equivalent Cl atoms. All Ac–Cl bond lengths are 3.86 Å. Cl is bonded to twelve equivalent Ac atoms to form a mixture of corner and face-sharing ClAc12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaAcAu2 by Materials Project

CaAcAu2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca is bonded in a body-centered cubic geometry to eight equivalent Au atoms. All Ca–Au bond lengths are 3.29 Å. Ac is bonded in a body-centered cubic geometry to eight equivalent Au atoms. All Ac–Au bond lengths are 3.29 Å. Au is bonded in a body-centered cubic geometry to four equivalent Ca and four equivalent Ac atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ac3Au by Materials Project

Ac3Au is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ac is bonded in a distorted square co-planar geometry to four equivalent Au atoms. All Ac–Au bond lengths are 3.71 Å. Au is bonded to twelve equivalent Ac atoms to form a mixture of corner and face-sharing AuAc12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3Ac by Materials Project

Ba3Ac is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ba is bonded to eight equivalent Ba and four equivalent Ac atoms to form distorted BaBa8Ac4 cuboctahedra that share corners with four equivalent AcBa12 cuboctahedra, corners with fourteen equivalent BaBa8Ac4 cuboctahedra, edges with six equivalent AcBa12 cuboctahedra, edges with twelve equivalent BaBa8Ac4 cuboctahedra, faces with four equivalent AcBa12 cuboctahedra, and faces with sixteen equivalent BaBa8Ac4 cuboctahedra. There are a spread of Ba–Ba bond distances ranging from 4.26–4.47 Å. There are two shorter (4.25 Å) and two longer (4.36 Å) Ba–Ac bond lengths. Ac is bonded to twelve equivalent Ba atoms to form AcBa12 cuboctahedra that share corners with six equivalent AcBa12 cuboctahedra, corners with twelve equivalent BaBa8Ac4 cuboctahedra, edges with eighteen equivalent BaBa8Ac4 cuboctahedra, faces with eight equivalent AcBa12 cuboctahedra, and faces with twelve equivalent BaBa8Ac4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaAcGa2 by Materials Project

CaAcGa2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca is bonded in a body-centered cubic geometry to eight equivalent Ga atoms. All Ca–Ga bond lengths are 3.31 Å. Ac is bonded in a body-centered cubic geometry to eight equivalent Ga atoms. All Ac–Ga bond lengths are 3.31 Å. Ga is bonded in a body-centered cubic geometry to four equivalent Ca and four equivalent Ac atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcPrMg2 by Materials Project

Mg2AcPr is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mg is bonded in a body-centered cubic geometry to four equivalent Ac and four equivalent Pr atoms. All Mg–Ac bond lengths are 3.47 Å. All Mg–Pr bond lengths are 3.47 Å. Ac is bonded in a body-centered cubic geometry to eight equivalent Mg atoms. Pr is bonded in a body-centered cubic geometry to eight equivalent Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcLaCd2 by Materials Project

AcLaCd2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ac is bonded in a body-centered cubic geometry to eight equivalent Cd atoms. All Ac–Cd bond lengths are 3.48 Å. La is bonded in a body-centered cubic geometry to eight equivalent Cd atoms. All La–Cd bond lengths are 3.48 Å. Cd is bonded in a body-centered cubic geometry to four equivalent Ac and four equivalent La atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiAcHg2 by Materials Project

LiAcHg2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Li is bonded in a distorted body-centered cubic geometry to eight equivalent Hg atoms. All Li–Hg bond lengths are 3.30 Å. Ac is bonded in a body-centered cubic geometry to eight equivalent Hg atoms. All Ac–Hg bond lengths are 3.30 Å. Hg is bonded in a body-centered cubic geometry to four equivalent Li and four equivalent Ac atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

PV Inverter Systems Enabled by Monolithically Integrated SiC based Four Quadrant Power Switch (4-QPS) [BiDFET]

The purpose of this project was to develop a new breed of Power Conversion Systems (PCS) for PV integration that is enabled by the newly developed 4-Quadrant Single Die SiC Power Semiconductor Switches (4-QPS) or also referred to as “Bidirectional FET (BIDFET)”. This work includes semiconductor die development, advanced packaging, converter design, development, and testing of 4-QPS enabled hardware prototypes at 1 kW (for single phase residential application) and 10 kW (for three phase commercial application). The BiDirectional Field-Effect Transistor (BiDFET) can enable circuit topologies requiring four-quadrant switches, that were earlier designed using discrete combinations of MOSFETs, IGBTs, GaN HEMTs, and PiN diodes. The monolithic nature of the BiDFET allows lower device count, smaller switch volume, lower inductance, and simpler packaging, and hence more reliable and commercially viable implementation in power electronics converters. The matrix converter topologies, now feasible using BiDFETs, can eliminate the bulky and unreliable dc link capacitors or inductors required for conventional voltage-source or current-source converters in ac–ac and ac–dc applications. The 1.2 kV BiDFET has the potential to disrupt all the applications utilizing 1.2 kV switches, including electric vehicle (EV) drivetrain, bidirectional EV chargers, industrial motor drives, solid-state transformers, datacenter power supplies, elevator drives, dc microgrids, energy storage grid integration, solid-state breakers, etc.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Example Alternative Compliance Waiver Application: EPAct State and Alternative Provider Fleet Program Guidance Document

The U.S. Department of Energy developed an electronic planning spreadsheet to facilitate fleets' preparation of a complete Alternative Compliance (AC) waiver application. All fleets that participate in AC are encouraged to use the spreadsheet. The example in this guidance document includes all components that must be included in a fleet’s AC waiver application.

AC waiver↗
DOE OSTI2023

Hierarchical Porous Activated Carbon from Wheat Bran Agro-Waste: Applications in Carbon Dioxide Capture, Dye Removal, Oxygen and Hydrogen Evolution Reactions

Here this work reports an efficient method for facile synthesis of hierarchically porous carbon (WB-AC) utilizing wheat bran waste. Obtained carbon showed 2.47 mmol g -1 CO 2 capture capacity with good CO 2 /N 2 selectivity and 27.35 to 29.90 kJ mol -1 isosteric heat of adsorption. Rapid removal of MO dye was observed with a capacity of ~555 mg g -1 . Moreover, WB-AC demonstrated a good OER activity with 0.35 V low overpotential at 5 mA cm -2 and a Tafel slope of 115 mV dec -1 . It also exhibited high electrocatalytic HER activity with 57 mV overpotential at 10 mA cm -2 and a Tafel slope of 82.6 mV dec -1 . The large SSA (757 m 2 g -1 ) and total pore volume (0.3696 cm 3 g -1 ) result from N 2 activation contributing to selective CO 2 uptake, high and rapid dye removal capacity and superior electrochemical activity (OER/HER), suggesting the use of WB-AC as cost effective adsorbent and metal free electrocatalyst.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

A statistical approach to analyzing domain dynamics in ferroelectric crystals using X-ray photon correlation spectroscopy

Ferroelectric materials exhibit strong electromechanical coupling, largely influenced by their domain structures. Numerous microstructural studies indicate that smaller domains with higher domain wall density generally enhance domain wall motion, although some inconsistencies have been reported. In this work, we use X-ray photon correlation spectroscopy (XPCS) to probe dynamic response in Pb(Mg 1/3 Nb 2/3 )O 3 -29PbTiO 3 (PMN-29PT) single crystals under applied electric fields. We introduce a two-field correlation approach, adapted from conventional two-time correlation to quantify dynamics. Statistical analysis reveals that both [001]-oriented direct current (DC) and alternating current (AC) poled samples show Poisson-like behavior within specific electric field regions. The DC-poled samples exhibit more frequent domain wall jump events but with smaller amount of decorrelation per jump event, whereas the AC-poled samples show fewer jump events with larger decorrelation per jump event. This observation aligns with the prevalence of 109° domain walls in the AC-poled samples, which contribute to more domain wall motion. These findings provide experimental evidence of collective domain wall motion and establish a direct connection between mesoscale dynamics and electromechanical response.

36 MATERIALS SCIENCE↗
DOE OSTI2024

An alcove at the acetyl-CoA synthase nickel active site is required for productive substrate CO binding and anaerobic carbon fixation

One of the seven natural CO 2 fixation pathways, the anaerobic Wood-Ljungdahl pathway (WLP) is unique in generating CO as a metabolic intermediate, operating through organometallic intermediates, and in conserving (versus utilizing) net ATP. The key enzyme in the WLP is acetyl-CoA synthase (ACS), which uses an active site [2Ni-4Fe-4S] cluster (A-cluster), a CO tunnel, and an organometallic (Ni-CO, Ni-methyl, and Ni-acetyl) reaction sequence to generate acetyl-CoA. Here, we reveal that an alcove, which interfaces the tunnel and the A-cluster, is essential for CO 2 fixation and autotrophic growth by the WLP. In vitro spectroscopy, kinetics, binding, and in vivo growth experiments reveal that a Phe229A substitution at one wall of the alcove decreases CO affinity thirty-fold and abolishes autotrophic growth; however, a F229W substitution enhances CO binding 80-fold. Our results indicate that the structure of the alcove is exquisitely tuned to concentrate CO near the A-cluster; protect ACS from CO loss during catalysis, provide a haven for inhibitory CO, and stabilize the tetrahedral coordination at the Nip site where CO binds. The directing, concentrating, and protective effects of the alcove explain the inability of F209A to grow autotrophically. The alcove also could help explain current controversies over whether ACS binds CO and methyl through a random or ordered mechanism. Our work redefines what we historically refer to as the metallocenter "active site". The alcove is so crucial for enzymatic function that we propose it is part of the active site. The community should now look for such alcoves in all "gas handling" metalloenzymes.

bacterial metabolism↗
DOE OSTI2025

The efficacy and ecological impact of mercury sorbents on the physiology and reproductive fitness of Daphnia magna

Environmental mercury (Hg) contamination threatens ecosystems due to its bioaccumulation and toxicity. Effective and sustainable remediation strategies are essential, with carbon-based sorbents like biochar (BC) and activated carbon (AC) gaining attention for their high adsorption capacity and cost-effectiveness. However, their ecological impacts remain poorly understood. This study evaluates the Hg removal efficacy and ecological effects of three sorbents—BC, granular AC (GAC), and AC fiber (ACF)—in a flow-through column system with and without Hg additions. We tested Hg removal at two concentrations (1 and 4 µg/L Hg) and assessed chronic exposure effects on a sentinel and sensitive freshwater organism, Daphnia magna, over 30 days of exposure to the columns’ effluent. GAC removed 100 % of Hg, while BC and ACF achieved 99 % removal. The ACF + 4 µg/L Hg effluent induced 70 % lethality in D. magna after nearly three weeks of exposure, while the GAC effluent significantly reduced fecundity, even in the absence of Hg exposure. In contrast, the BC effluent enhanced reproductive output, likely due to inputs of carbon and nitrogen in the effluent. These findings highlight the need to balance Hg removal efficacy with ecological safety, emphasizing the importance of considering both remediation effectiveness and potential environmental impacts.

Activated carbon↗
DOE OSTI2021

Guided skyrmion motion along pinning array interfaces

We examine ac driven skyrmions interacting with the interface between two different obstacle array structures. We consider drive amplitudes at which skyrmions in a bulk obstacle lattice undergo only localized motion and show that when an obstacle lattice interface is introduced, directed skyrmion transport can occur along the interface. The skyrmions can be guided by a straight interface and can also turn corners to follow the interface. For a square obstacle lattice embedded in a square pinning array with a different obstacle radius, we find that skyrmions can undergo transport in all four primary symmetry directions under the same fixed ac drive. We map where localized or translating motion occurs as a function of the ac driving parameters. Our results suggest a new method for controlling skyrmion motion based on transport along obstacle lattice interfaces.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗