Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “La”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on La(AsIr)2 by Materials Project

LaIr2As2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. La is bonded in a 4-coordinate geometry to eight Ir and eight As atoms. There are four shorter (3.32 Å) and four longer (3.37 Å) La–Ir bond lengths. There are four shorter (3.28 Å) and four longer (3.30 Å) La–As bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 12-coordinate geometry to four equivalent La and four equivalent As atoms. All Ir–As bond lengths are 2.58 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent La and five As atoms. There are one shorter (2.47 Å) and four longer (2.48 Å) Ir–As bond lengths. There are two inequivalent As sites. In the first As site, As is bonded in a 8-coordinate geometry to four equivalent La and four equivalent Ir atoms. In the second As site, As is bonded in a 9-coordinate geometry to four equivalent La and five Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(ClO)3 by Materials Project

La(OCl)3 crystallizes in the hexagonal P-62m space group. The structure is one-dimensional and consists of one La(OCl)3 ribbon oriented in the (0, 0, 1) direction. La is bonded in a 3-coordinate geometry to three equivalent O and six equivalent Cl atoms. All La–O bond lengths are 2.49 Å. All La–Cl bond lengths are 2.93 Å. O is bonded in a single-bond geometry to one La atom. Cl is bonded in an L-shaped geometry to two equivalent La atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(GaPd)2 by Materials Project

LaPd2Ga2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. La is bonded in a 12-coordinate geometry to eight Pd and eight Ga atoms. There are four shorter (3.37 Å) and four longer (3.38 Å) La–Pd bond lengths. There are four shorter (3.36 Å) and four longer (3.40 Å) La–Ga bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 4-coordinate geometry to four equivalent La and four equivalent Ga atoms. All Pd–Ga bond lengths are 2.55 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to four equivalent La and five Ga atoms. There are one shorter (2.52 Å) and four longer (2.57 Å) Pd–Ga bond lengths. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded in a 4-coordinate geometry to four equivalent La and four equivalent Pd atoms. In the second Ga site, Ga is bonded in a 5-coordinate geometry to four equivalent La and five Pd atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2023

Multiyear La Niña Events and Multiseason Drought in the Horn of Africa

One of the primary sources of predictability for seasonal hydroclimate forecasts are sea surface temperatures (SSTs) in the tropical Pacific, including El Niño–Southern Oscillation. Multiyear La Niña events in particular may be both predictable at long lead times and favor drought in the bimodal rainfall regions of East Africa. However, SST patterns in the tropical Pacific and adjacent ocean basins often differ substantially between first- and second-year La Niñas, which can change how these events affect regional climate. Here, we demonstrate that multiyear La Niña events favor drought in the Horn of Africa in three consecutive seasons [October–December (OND), March–May (MAM), OND]. But they do not tend to increase the probability of a fourth season of drought owing to the sea surface temperatures and associated atmospheric teleconnections in the MAM long rains season following second-year La Niña events. First-year La Niñas tend to have both greater subsidence over the Horn of Africa, associated with warmer waters in the west Pacific that enhance the Walker circulation, and greater cross-continental moisture transport, associated with a warm tropical Atlantic, as compared to second-year La Niñas. Both the increased subsidence and enhanced cross-continental moisture transport favors drought in the Horn of Africa. Our results provide a physical understanding of the sources and limitations of predictability for using multiyear La Niña forecasts to predict drought in the Horn of Africa.

Climate variability↗
DOE OSTI2021

Liquid state properties and solidification features of the pseudo binary BaS-La 2 S 3

The high temperature thermodynamic properties of chalcogenides materials based on BaS remain elusive. Herein the pseudo binary BaS-La 2 S 3 is investigated above 1573 K. The liquid properties of BaS-La 2 S 3 are measured by means of high resolution in-situ visualization coupled with thermal arrest measurements in a thermal imaging furnace. This enables to report the first observation of such melts in a container-less setting. The melting points of BaS and La 2 S 3 are revisited at 2454 K and 2004 K respectively. La 2 S 3 demonstrates a high stability in its liquid state, in strike difference with the sublimation observed for BaS. BaS is however partially stabilized with the addition of few percents of La 2 S 3 . The remarkable chemical and thermal stability of La 2 S 3 -rich samples contrasts with the partial decomposition and high vapor pressure observed for BaS-rich samples. Observations and analysis of the solidified samples suggest three different solid solutions. Solid and liquid densities are investigated along the different compositions, supporting a first estimate of the volumetric thermal expansion coefficient for La 2 S 3 .

36 MATERIALS SCIENCE↗
DOE OSTI2024

Resilience of the Aurivillius structure upon La and Cr doping in a Bi 5 Ti 3 FeO 15 multiferroic

Here, combining the experimental techniques of high-resolution X-ray diffraction, magnetometry, specific heat measurement, and X-ray photoelectron, Raman and dielectric spectroscopy techniques, we have studied the influence of La and Cr doping on the crystal structure and magnetism of the room temperature Aurivillius multiferroic Bi 5 Ti 3 FeO 15 by investigating the physical properties of (Bi 4 La)Ti 3 FeO 15 and Bi 5 Ti 3 (Fe 0.5 Cr 0.5 )O 15 . The parent (Bi 5 Ti 3 FeO 15 ) and the doped ((Bi 4 La)Ti 3 FeO 15 and Bi 5 Ti 3 (Fe 0.5 Cr 0.5 )O 15 ) compounds crystallize in the A2 1 am space group, which is confirmed through our analysis of high-resolution synchrotron X-ray diffraction data obtained on phase-pure polycrystalline powders. We determined the oxidation states of the metal atoms in the studied compounds as Fe 3+ , Ti 4+ , Cr 3+ , and La 3+ through the analysis of X-ray photoelectron spectroscopy data. The magnetic susceptibilities of the three compounds are marked by the absence of a long-range ordered ground state, but dominated by superparamagnetic clusters with dominant antiferromagnetic interactions. This signature of short-range magnetism is also seen in specific heat as a low temperature enhancement which is suppressed upon the application of external magnetic fields up to 8 T. Our dielectric spectroscopy experiments showed that the three studied compounds display similar features in the dielectric constant measured as a function of frequency. However, upon doping La at the Bi site, the width of the ferroelectric hysteresis loop increases for (Bi 4 La)Ti 3 FeO 15 compared to that of the parent compound Bi 5 Ti 3 FeO 15 , and with Cr doping, Bi 5 Ti 3 (Fe 0.5 Cr 0.5 )O 15 becomes a leaky dielectric. The resilience of the Aurivillius crystal structure towards doping of La at the Bi site and Cr at the Fe site is clearly seen in the bulk properties of magnetic susceptibility, specific heat and the average crystal structure. The relevance of changes in the local structure is evident from our Raman spectroscopy and X-ray pair distribution function studies.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Estudio de Resiliencia de la Red Electrica de Puerto Rico y Transiciones a Energia 100% Renovable (PR100)

Puerto Rico se ha comprometido a satisfacer sus necesidades de energia 100% renovable para 2050, ademas de alcanzar metas intermedias del 40% para 2025, 60% para 2040, la eliminacion gradual de la generacion a carbon para 2028 y una mejora del 30% en la eficiencia energetica para 2040, segun lo establecido en la Ley de Politica Publica Energetica de Puerto Rico (Ley 17). Para cumplir con estos objetivos y apoyar la electrificacion generalizada, Puerto Rico esta explorando la energia renovable y el almacenamiento de energia, la generacion distribuida, el control de distribucion, los vehiculos electricos y las cargas receptivas y eficientes energeticas que se pueden implementar en las comunidades de Puerto Rico. See NREL/FS-6A20-85442 (https://www.nrel.gov/docs/fy23osti/85442.pdf) for the English translation.

ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2020

Materials Data on La(GeRh)2 by Materials Project

La(RhGe)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La is bonded in a 8-coordinate geometry to eight equivalent Rh and eight equivalent Ge atoms. All La–Rh bond lengths are 3.40 Å. All La–Ge bond lengths are 3.28 Å. Rh is bonded to four equivalent La and four equivalent Ge atoms to form a mixture of distorted corner, edge, and face-sharing RhLa4Ge4 tetrahedra. All Rh–Ge bond lengths are 2.49 Å. Ge is bonded in a 9-coordinate geometry to four equivalent La, four equivalent Rh, and one Ge atom. The Ge–Ge bond length is 2.71 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(ClO4)3 by Materials Project

La(ClO4)3 crystallizes in the trigonal R3c space group. The structure is three-dimensional. La is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of La–O bond distances ranging from 2.50–2.60 Å. There are four inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one La and one Cl atom. The O–Cl bond length is 1.48 Å. In the second O site, O is bonded in a bent 150 degrees geometry to one La and one Cl atom. The O–Cl bond length is 1.47 Å. In the third O site, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.42 Å. In the fourth O site, O is bonded in a water-like geometry to one La and one Cl atom. The O–Cl bond length is 1.48 Å. Cl is bonded in a tetrahedral geometry to four O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(BIr)4 by Materials Project

La(IrB)4 is alpha Pu-derived structured and crystallizes in the tetragonal P4_2/n space group. The structure is three-dimensional. La is bonded in a 4-coordinate geometry to eight equivalent Ir and twelve equivalent B atoms. There are four shorter (3.19 Å) and four longer (3.29 Å) La–Ir bond lengths. There are a spread of La–B bond distances ranging from 2.94–3.47 Å. Ir is bonded in a 4-coordinate geometry to two equivalent La and four equivalent B atoms. There are a spread of Ir–B bond distances ranging from 2.11–2.17 Å. B is bonded in a 6-coordinate geometry to three equivalent La, four equivalent Ir, and one B atom. The B–B bond length is 1.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(Mg4Al3)4 by Materials Project

La(Mg4Al3)4 crystallizes in the cubic I-43m space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 12-coordinate geometry to seven Mg and five equivalent Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.01–3.18 Å. There are a spread of Mg–Al bond distances ranging from 2.84–3.17 Å. In the second Mg site, Mg is bonded in a 10-coordinate geometry to three equivalent Mg, one La, and six equivalent Al atoms. The Mg–La bond length is 3.34 Å. All Mg–Al bond lengths are 3.23 Å. La is bonded in a 12-coordinate geometry to four equivalent Mg and twelve equivalent Al atoms. All La–Al bond lengths are 3.27 Å. Al is bonded in a 11-coordinate geometry to seven Mg, one La, and three equivalent Al atoms. There are one shorter (2.75 Å) and two longer (2.81 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(Al2Fe)4 by Materials Project

LaFe4Al8 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La is bonded in a 12-coordinate geometry to eight equivalent Fe and twelve Al atoms. All La–Fe bond lengths are 3.37 Å. There are four shorter (3.04 Å) and eight longer (3.22 Å) La–Al bond lengths. Fe is bonded to two equivalent La, two equivalent Fe, and eight Al atoms to form a mixture of distorted corner, edge, and face-sharing FeLa2Al8Fe2 cuboctahedra. Both Fe–Fe bond lengths are 2.52 Å. There are four shorter (2.55 Å) and four longer (2.68 Å) Fe–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to two equivalent La, four equivalent Fe, and six Al atoms. There are a spread of Al–Al bond distances ranging from 2.73–2.83 Å. In the second Al site, Al is bonded in a 10-coordinate geometry to one La, four equivalent Fe, and five Al atoms. The Al–Al bond length is 2.75 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(AgGe)2 by Materials Project

La(AgGe)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La is bonded in a 8-coordinate geometry to eight equivalent Ag and eight equivalent Ge atoms. All La–Ag bond lengths are 3.53 Å. All La–Ge bond lengths are 3.35 Å. Ag is bonded in a 12-coordinate geometry to four equivalent La, four equivalent Ag, and four equivalent Ge atoms. All Ag–Ag bond lengths are 3.11 Å. All Ag–Ge bond lengths are 2.68 Å. Ge is bonded in a 9-coordinate geometry to four equivalent La, four equivalent Ag, and one Ge atom. The Ge–Ge bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(Ge2Rh3)2 by Materials Project

La(Rh3Ge2)2 crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. La is bonded to six equivalent Rh and six equivalent Ge atoms to form face-sharing LaGe6Rh6 cuboctahedra. All La–Rh bond lengths are 3.20 Å. All La–Ge bond lengths are 3.18 Å. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 5-coordinate geometry to five Ge atoms. There are one shorter (2.51 Å) and four longer (2.58 Å) Rh–Ge bond lengths. In the second Rh site, Rh is bonded in a 6-coordinate geometry to two equivalent La and four Ge atoms. There are two shorter (2.51 Å) and two longer (2.57 Å) Rh–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to nine Rh atoms. In the second Ge site, Ge is bonded in a 10-coordinate geometry to two equivalent La and six Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(Ga5Mo)8 by Materials Project

La(MoGa5)8 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. La is bonded in a 6-coordinate geometry to two equivalent Mo and six equivalent Ga atoms. Both La–Mo bond lengths are 3.25 Å. All La–Ga bond lengths are 3.08 Å. There are two inequivalent Mo sites. In the first Mo site, Mo is bonded in a 10-coordinate geometry to one La and nine Ga atoms. There are a spread of Mo–Ga bond distances ranging from 2.62–2.68 Å. In the second Mo site, Mo is bonded in a distorted q6 geometry to ten Ga atoms. There are a spread of Mo–Ga bond distances ranging from 2.57–2.71 Å. There are eight inequivalent Ga sites. In the first Ga site, Ga is bonded in a cuboctahedral geometry to twelve Ga atoms. There are six shorter (2.92 Å) and six longer (3.04 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded in a distorted linear geometry to two equivalent Mo atoms. In the third Ga site, Ga is bonded in a 2-coordinate geometry to two equivalent Mo and two equivalent Ga atoms. There are one shorter (2.78 Å) and one longer (3.00 Å) Ga–Ga bond lengths. In the fourth Ga site, Ga is bonded in a distorted bent 150 degrees geometry to two equivalent Mo and one Ga atom. In the fifth Ga site, Ga is bonded in a distorted bent 150 degrees geometry to two Mo and one Ga atom. In the sixth Ga site, Ga is bonded in a 2-coordinate geometry to two equivalent Mo and one Ga atom. The Ga–Ga bond length is 2.70 Å. In the seventh Ga site, Ga is bonded in a 2-coordinate geometry to two Mo and two equivalent Ga atoms. There are one shorter (2.75 Å) and one longer (2.94 Å) Ga–Ga bond lengths. In the eighth Ga site, Ga is bonded in a 8-coordinate geometry to one La, two Mo, and five Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(Sn2Rh)2 by Materials Project

La(RhSn2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. La is bonded in a 6-coordinate geometry to seven Sn atoms. There are a spread of La–Sn bond distances ranging from 3.22–3.38 Å. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 7-coordinate geometry to seven Sn atoms. There are a spread of Rh–Sn bond distances ranging from 2.72–2.92 Å. In the second Rh site, Rh is bonded in a 7-coordinate geometry to seven Sn atoms. There are a spread of Rh–Sn bond distances ranging from 2.73–2.84 Å. There are four inequivalent Sn sites. In the first Sn site, Sn is bonded in a 6-coordinate geometry to two equivalent La and four Rh atoms. In the second Sn site, Sn is bonded in a 5-coordinate geometry to two equivalent La and three equivalent Rh atoms. In the third Sn site, Sn is bonded in a 3-coordinate geometry to three equivalent La and three equivalent Rh atoms. In the fourth Sn site, Sn is bonded to four Rh atoms to form a mixture of distorted edge and corner-sharing SnRh4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(ReB)4 by Materials Project

La(ReB)4 crystallizes in the tetragonal P4_2/nmc space group. The structure is three-dimensional. La is bonded in a 12-coordinate geometry to twelve equivalent Re and twelve equivalent B atoms. There are four shorter (3.11 Å) and eight longer (3.23 Å) La–Re bond lengths. There are eight shorter (3.09 Å) and four longer (3.27 Å) La–B bond lengths. Re is bonded in a 5-coordinate geometry to three equivalent La and five equivalent B atoms. There are a spread of Re–B bond distances ranging from 2.23–2.35 Å. B is bonded in a 6-coordinate geometry to three equivalent La, five equivalent Re, and one B atom. The B–B bond length is 1.85 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Machine Learning-Guided Discovery of Ternary Compounds Containing La, P, and Group 14 Elements

In this work, we integrate a deep machine learning (ML) method with first-principles calculations to efficiently search for the energetically favorable ternary compounds. Using La–Si–P as a prototype system, we demonstrate that ML-guided first-principles calculations can efficiently explore crystal structures and their relative energetic stabilities, thus greatly accelerate the pace of material discovery. A number of new La–Si–P ternary compounds with formation energies less than 30 meV/atom above the known ternary convex hull are discovered. Among them, the formation energies of La 5 SiP 3 and La 2 SiP phases are only 2 and 10 meV/atom, respectively, above the convex hull. These two compounds are dynamically stable with no imaginary phonon modes. Moreover, by replacing Si with heavier-group 14 elements in the eight lowest-energy La–Si–P structures from our ML-guided predictions, a number of low-energy La–X–P phases (X = Ge, Sn, Pb) are predicted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗