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Results for “planar structures”

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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on HfBeSi by Materials Project

BeHfSi crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Be is bonded in a distorted trigonal planar geometry to six equivalent Hf and three equivalent Si atoms. All Be–Hf bond lengths are 2.79 Å. All Be–Si bond lengths are 2.14 Å. Hf is bonded to six equivalent Be and six equivalent Si atoms to form a mixture of edge and face-sharing HfBe6Si6 cuboctahedra. All Hf–Si bond lengths are 2.79 Å. Si is bonded in a distorted trigonal planar geometry to three equivalent Be and six equivalent Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiAs3 by Materials Project

LiAs3 is Sodium arsenide structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Li1+ is bonded in a distorted trigonal planar geometry to eleven As+0.33- atoms. There are a spread of Li–As bond distances ranging from 2.43–3.13 Å. There are two inequivalent As+0.33- sites. In the first As+0.33- site, As+0.33- is bonded in a 10-coordinate geometry to four equivalent Li1+ and six As+0.33- atoms. There are three shorter (2.80 Å) and three longer (2.99 Å) As–As bond lengths. In the second As+0.33- site, As+0.33- is bonded in a trigonal planar geometry to three equivalent Li1+ and six equivalent As+0.33- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Unravelling the mechanism of pressure induced polyamorphic transition in an inorganic molecular glass

The atomic structure of a germanium doped phosphorous selenide glass of composition Ge 2.8 P 57.7 Se 39.5 is determined as a function of pressure from ambient to 24 GPa using Monte-Carlo simulations constrained by high energy x-ray scattering data. The ambient pressure structure consists primarily of P 4 Se 3 molecules and planar edge shared phosphorus rings, reminiscent of those found in red phosphorous as well as a small fraction of locally clustered corner-sharing GeSe 4 tetrahedra. This low-density amorphous phase transforms into a high-density amorphous phase at ~6.3 GPa. The high-pressure phase is characterized by an extended network structure. The polyamorphic transformation between these two phases involves opening of the P 3 ring at the base of the P 4 Se 3 molecules and subsequent reaction with red phosphorus type moieties to produce a cross linked structure. The compression mechanism of the low-density phase involves increased molecular packing, whereas that of the high pressure phase involves an increase in the nearest-neighbor coordination number while the bond angle distributions broaden and shift to smaller angles. The entropy and volume changes associated with this polyamorphic transformation are positive and negative, respectively, and consequently the corresponding Clapeyron slope for this transition would be negative. This result has far reaching implications in our current understanding of the thermodynamics of polyamorphic transitions in glasses and glass-forming liquids.

42 ENGINEERING↗
DOE OSTI2021

Processable High Electron Mobility {pi}-Copolymers via Mesoscale Backbone Conformational Ordering

The synthesis and experimental/theoretical characterization of a new series of electron-transporting copolymers based on the naphthalene bis(4,8-diamino-1,5-dicarboxyl)amide (NBA) building block are reported. Comonomers are designed to test the emergent effects of manipulating backbone torsional characteristics, and density functional theory (DFT) analysis reveals the key role of backbone conformation in optimizing electronic delocalization and transport. The NBA copolymer conformational and electronic properties are characterized using a broad array of molecular/macromolecular, thermal, optical, electrochemical, and charge transport techniques. All NBA copolymers exhibit strongly aggregated morphologies with significant nanoscale order. Copolymer charge transport properties are investigated in thin-film transistors and exhibit excellent electron mobilities ranging from 0.4 to 4.5 cm(2) V-1 s(-1). Importantly, the electron transport efficiency correlates with the film mesoscale order, which emerges from comonomer-dependent backbone planarity and extension. These results illuminate the key NBA building block structure-morphology-bulk property design relationships essential for processable, electronics-applicable high-performance polymeric semiconductors.

n‐↗
NASA NTRS1978

Structure of current sheets in magnetic holes at 1 AU

Current density profiles in several types of interplanetary magnetic holes were calculated assuming that the currents flow in planar sheets and that the magnetic field varies only in the direction normal to the sheet. The planarity was verified in four holes which were observed by two suitably spaced spacecraft. The structure of the current sheets ranges from very simple in some holes to very complex in others. The observed structures are found to be qualitatively consistent with models based on self-consistent solutions of Vlasov's equation and Maxwell's equations. Examples of complex, irregular magnetic holes are also presented, and they are shown to contain multiple, current sheets in which currents flow parallel to one another.

Fitzenreiter, R. J.↗
DOE OSTI2023

Recycling the Energy of Indoor Light: Highly Efficient Organic Photovoltaics via a Ternary Strategy

A ternary approach in organic photovoltaics (OPV) is simple and reliable to effectively tune the optical, electrical and morphological properties of the photoactive layer for high efficiency as well as long-term stability under 1 sun. However, there have been few papers reporting spectra and weak illumination compared to outdoor light. In this study, by using two compatible 16 structures, we demonstrate a simultaneous modulation of light absorption and molecular donor polymers (PM7 and PM7 D1) with slightly-different band gaps and similar chemical packing under ambient conditions, which resulted in efficient indoor OPVs exhibiting power conversion efficiency (PCE) over 20% under 1000 lux of warm white light-emitting diode (2900 K). From morphological analysis, we infer that PM7 serves to seed nucleation of PM7 D1 in the ternary blend, templating its crystallization and alignment along the PM7 backbone. Such templating effect leads to increased domain spacing and relative degree of crystallinity (rDoC) compared to those of each binary system. We further show that higher rDoC helps suppress both bimolecular and trap-assisted recombination of photogenerated charges in the ternary devices. As a result, the complementary absorption and synergistic molecular assembly of the two donor polymers enhance the short-circuit current density as to increase the average PCEs from 9.6 to 10.3% under 1 sun and from 18.7 to 20.0% under 1000 lux. We envision that our strategy of incorporating both a planar and a flexible donor polymer with similar chemical structures can be generally applicable to attain a high performance ternary OPV under both 1 sun and indoor light.

14 SOLAR ENERGY↗
DOE OSTI2020

Materials Data on Cu3(SnO3)4 by Materials Project

Cu3(SnO3)4 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. Cu+2.67+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.90 Å. Sn4+ is bonded to six equivalent O2- atoms to form corner-sharing SnO6 octahedra. The corner-sharing octahedral tilt angles are 46°. All Sn–O bond lengths are 2.09 Å. O2- is bonded in a trigonal planar geometry to one Cu+2.67+ and two equivalent Sn4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu3(GeO3)4 by Materials Project

Cu3(GeO3)4 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. Cu+2.67+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.90 Å. Ge4+ is bonded to six equivalent O2- atoms to form corner-sharing GeO6 octahedra. The corner-sharing octahedral tilt angles are 40°. All Ge–O bond lengths are 1.93 Å. O2- is bonded in a distorted trigonal planar geometry to one Cu+2.67+ and two equivalent Ge4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U2BiN2 by Materials Project

U2N2Bi crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a square co-planar geometry to four equivalent Bi and four equivalent N atoms. All U–Bi bond lengths are 3.47 Å. All U–N bond lengths are 2.30 Å. Bi is bonded in a 2-coordinate geometry to eight equivalent U and two equivalent N atoms. Both Bi–N bond lengths are 2.88 Å. N is bonded in a distorted square co-planar geometry to four equivalent U and one Bi atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiBiF2 by Materials Project

LiBiF2 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Li1+ is bonded in a square co-planar geometry to four equivalent F1- atoms. There is two shorter (1.92 Å) and two longer (1.96 Å) Li–F bond length. Bi1+ is bonded in a linear geometry to two equivalent F1- atoms. Both Bi–F bond lengths are 2.32 Å. F1- is bonded in a distorted trigonal planar geometry to two equivalent Li1+ and one Bi1+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2003

Low Temperature SQUID for NDE Applications

We have developed a low temperature SuperConducting Quantum Interference Device - SQUID measurement system for detection of defects deep under the surface of aluminum structures using eddy current techniques. The system uses a two dimensional planar inducer with two different excitation frequencies to induce a current in the sample. We have developed a data analysis software program that enabled us to distinguish between round defects (holes), straight defects (slots) and slots close to holes simulating cracks starting from rivets in aluminum structures. We were able to detect defects that are 8mm below the surface. We have also measured the change in phase of the detected signal as a function of depth of the defect. This relationship can be used to determine the depth of hidden flaws. Using this analysis software with the high temperature SQUID system at NASA Langley we were able to detect slots close to holes in layered aluminum sample.

Wincheski, Buzz↗
DOE OSTI2020

Materials Data on ZrTaNO by Materials Project

ZrTaNO crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Zr2+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All Zr–O bond lengths are 2.12 Å. Ta3+ is bonded to three equivalent N3- and two equivalent O2- atoms to form corner-sharing TaN3O2 trigonal bipyramids. All Ta–N bond lengths are 2.12 Å. Both Ta–O bond lengths are 2.28 Å. N3- is bonded in a trigonal planar geometry to three equivalent Ta3+ atoms. O2- is bonded to three equivalent Zr2+ and two equivalent Ta3+ atoms to form corner-sharing OZr3Ta2 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Microstructure prediction for Ti-22Al-25Nb in laser powder bed fusion

This work presents a physics-informed framework for predicting solidification morphology and defect susceptibility in additively manufactured Ti–22Al–25Nb across a broad processing space. The framework integrates solidification microstructure selection (SMS) analysis with a single-track defect-based printability map to establish a unified methodology linking processing parameters to both interfacial morphology and manufacturability. Thermal gradients G and solidification rates R are first computed using the Thermo-Calc Additive Manufacturing (TC-AM) module, a finite-interface-dissipation (FID) phase-field (PF) model coupled with CALPHAD method is then employed to systematically distinguish planar and dendritic regimes as functions of $G$ and $R$. By superimposing the printability map onto the morphology projections, a comprehensive process–structure framework is obtained. Across most processing conditions, the predicted microstructure is predominantly dendritic, while planar growth emerges only under selected laser power $P$ and scan speed $v$ combinations. In addition to morphology classification, the framework quantifies the dendritic area fraction and introduces a width-based morphology descriptor to characterize the spatial extent of planar/dendritic regions within the melt pool. It provides mechanistic insight into the interplay between solidification physics and defect formation, offering practical guidance for parameter selection and microstructural control in Ti–22Al–25Nb additive manufacturing (AM).

36 MATERIALS SCIENCE↗
DOE OSTI2023

Molecular dynamics study of grain boundary and radiation effects on tritium population and diffusion in zirconium

Tritium population thermodynamics and transport kinetics critically define the tritium storage performance of zirconium tritides that can be used for a variety of nuclear applications including tritium-producing burnable absorber rods. Both thermodynamic and kinetic properties can be sensitive to grain sizes of materials and can be significantly altered by irradiated defects during operation under the reactor environments. A thorough experimental characterization of how these properties evolve under different reactor conditions and different initial grain structures is extremely challenging. Here molecular dynamics simulations are used to investigate tritium population and diffusion in zirconium with and without different planar symmetric and asymmetric tilt grain boundaries and irradiated defects. Here, we found that in addition to trapping tritium, the most significant effect of planar grain boundaries is to increase tritium diffusivity on the boundary plane. Furthermore, fine grain structures are found to mitigate the change of tritium diffusivity due to irradiated point defects as these point defects are likely to migrate to and sink at grain boundaries.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Sr2Si by Materials Project

Sr2Si crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a trigonal planar geometry to three equivalent Si4- atoms. All Sr–Si bond lengths are 3.13 Å. In the second Sr2+ site, Sr2+ is bonded to six equivalent Si4- atoms to form a mixture of corner, edge, and face-sharing SrSi6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Sr–Si bond lengths are 3.65 Å. Si4- is bonded in a distorted trigonal planar geometry to nine Sr2+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1984

Curved cap corrugated sheet

The report describes a structure for a strong, lightweight corrugated sheet. The sheet is planar or curved and includes a plurality of corrugation segments, each segment being comprised of a generally U-shaped corrugation with a part-cylindrical crown and cap strip, and straight side walls and with secondary corrugations oriented at right angles to said side walls. The cap strip is bonded to the crown and the longitudinal edge of said cap strip extends beyond edge at the intersection between said crown and said side walls. The high strength relative to weight of the structure makes it desirable for use in aircraft or spacecraft.

Davis, R. C.↗
DOE OSTI2020

Materials Data on AgAuF4 by Materials Project

AuAgF4 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Au3+ is bonded in a square co-planar geometry to four equivalent F1- atoms. All Au–F bond lengths are 1.99 Å. Ag1+ is bonded in a 8-coordinate geometry to eight equivalent F1- atoms. All Ag–F bond lengths are 2.56 Å. F1- is bonded in a distorted trigonal planar geometry to one Au3+ and two equivalent Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CdCuF4 by Materials Project

CuCdF4 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Cu2+ is bonded in a square co-planar geometry to four equivalent F1- atoms. All Cu–F bond lengths are 1.92 Å. Cd2+ is bonded in a 8-coordinate geometry to eight equivalent F1- atoms. All Cd–F bond lengths are 2.37 Å. F1- is bonded in a distorted trigonal planar geometry to one Cu2+ and two equivalent Cd2+ atoms.

36 MATERIALS SCIENCE↗