Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “GaNi”

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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Estimation of age of Dali-Ganis rifting and associated volcanic activity, Venus

This paper deals with the estimation of age for the Dali and Ganis Chasma rift zones and their associated volcanism based on photogeologic analysis of stratigraphic relations of rift-associated features with impact craters which have associated features indicative of their age. The features are radar-dark and parabolic, and they are believed to be mantles of debris derived from fallout of the craters' ejecta. They are thought to be among the youngest features on the Venusian surface, so their 'parent' craters must also be very young, evidently among the youngest 10 percent of Venus' crater population. Dali Chasma and Ganis Chasma are a part of a system of rift zones contained within eastern Aphrodite and Atla Regio which is a significant component of Venus tectonics. The rifts of this system are fracture belts which dissect typical Venusian plains with rare islands of tessera terrain. The rift zone system consists of several segments following each other (Diane, Dali, Ganis) and forming the major rift zone line, about 10,000 km long, which has junctions with several other rift zones, including Parga Chasma Rift. The junctions are usually locations of rift-associated volcanism in the form of volcanic edifices (Maat and Ozza Montes) or plain-forming flows flooding some areas within the rift zones and the adjacent plains.

Basilevsky, A. T.↗
NASA NTRS2003

Cosmogenic Records in 18 Ordinary Chondrites from the Dar Al Gani Region, Libya: Noble Gases - 1

In the last decade thousands of meteorites have been recovered from hot deserts in the Sahara and Oman. One of the main meteorite concentration surfaces in the Sahara is the Dar al Gani plateau in Libya, which covers a total area of ~8000 km2. More than 1000 meteorites have been reported from this area. The geological setting, meteorite pairings and the meteorite density of the Dar al Gani (DaG) field are described in more detail in [1]. In this work we report concentrations of the noble gas isotopes of He, Ne, Ar as well as 84Kr and 132Xe in 18 DaG meteorites. In a separate paper we will report the cosmogenic radionuclides [2]. We discuss the thermal history and cosmic-ray exposure (CRE) history of these meteorites, and evaluate the effects of the hot desert environment on the noble gas record.

Schultz, L.↗
NASA NTRSDate not supplied

The Chemical and Isotopic Signatures of the Hibonite-rich FUN Inclusion "HIDALGO" in Dar al Gani 027 (CO3)

Refractory Ca-Al-rich Inclusions (CAIs) with FUN (Fractionation with Unidentified Nuclear effects) characteristics are peculiar samples among all high-temperature components in chondritic meteorites. They are generally characterized by strong mass-dependent isotopic fractionations in several elements (e.g., O, Mg, Ca, Ti), large (~5-20‰) enrichments or depletions in neutron-rich isotopes (e.g., 48 Ca, 50 Ti, 54 Cr), and low inferred abundances of 26 Al ( 26 Al/ 27 Al < 1×10 −5 ). Understanding the origins of these features in FUN CAIs can shed light on the astrophysical environment and chemical processes that took place in the early Solar System. A large fraction (slightly less than 50%) of the ~20 FUN CAIs discovered so far are hibonite-rich (such as HAL, SHAL and DH-H1, collectively called HAL-type inclusions hereafter). According to their elemental and isotopic signatures and the results of evaporation experiments, HAL-type inclusions are thought to have formed as a distillation residue. However, questions regarding the timing of the formation of HAL-type inclusions (or FUN inclusions in general) relative to those of regular CAIs and the decoupling between the 26 Al abundances and nucleosynthetic anomalies remain poorly understood. In 2021, we reported the discovery of a new HAL-type inclusion, HIDALGO (Hibonite in Dar al Gani CO3) in the CO3 chondrite Dar al Gani 027 (DaG027), based on its (fractionated) oxygen isotopic compositions and low inferred 26 Al/ 27 Al ratio of (1.50±0.02)×10 −5 . Since then, more work on other short-lived and stable isotope systems and trace element abundances has been conducted. Here we report these new results and discuss the implications for the possible formation history of HIDALGO and origins of shortlived radionuclides (SLRs).

Meteorite↗
NASA NTRS2003

Cosmogenic Records in 18 Ordinary Chondrites from the Dar Al Gani Region, Libya: Radionclides - 2

In the past decade more than 1000 meteorites have been recovered from the Dar al Gani (DaG) plateau in the Libyan part of the Sahara. The geological setting, meteorite pairings and density are described. So far, only a few terrestrial ages are known for DaG meteorites, e.g. 60+/- 20 kyr for the DaG 476 shergottite shower and 80+/- 20 kyr for the lunar meteorite DaG 262. However, from other desert areas, such as Oman, it is known that achondrites may survive much longer than chondritic meteorites, so the ages of these two achondrites may not be representative of the majority of the DaG meteorite collection, of which more than 90% are ordinary chondrites. In this work we report concentrations of the cosmogenic radionuclides, 14C (half-life = 5,730 yr), 41Ca (1.04x10 superscript 5 yr), Cl-36 (3.01x10 superscript 5 yr), Al-26 (7.05x10 superscript 5 yr) and 10Be (1.5x10 superscript 6 yr) to determine the terrestrial ages of DaG meteorites and constrain their pre-atmospheric size and exposure history.

Welten, K. C.↗
NASA NTRS2024

Supra-Chondritic 7Li/6Li in the Hibonite-Rich Fun Inclusion “HIDALGO” in Dar al Gani 027 (CO3): A Hint for the Former Presence of Beryllium-7?

HIDALGO, a ~300×300 μm, hexagonally shaped, chemically and mineralogically simple hibonite crystal residing in the matrix of the CO3 chondrite Dar al Gani 027 (DaG027), is the newest member in the FUN-hibonite family. Based on the mass-dependent fractionations in O, Ca, and Ti isotopes, large negative anomalies in δ 48 Ca (= −30‰) and δ 50 Ti (= −20‰), and the abundances of short-lived radioisotopes of 10 Be, 26 Al, 41 Ca, which have all been reported previously, we have inferred that HIDALGO evolved from a condensate that most likely formed before 26 Al was built up and homogenized to 26 Al/ 27 Al = 5.2×10 −5 in the solar system. This precursor also incorporated 10 Be at the level of 10 Be/ 9 Be = 7.5×10 −4 , possibly through local irradiation of gas and/or dust or inheritance from the molecular cloud, but the amount of 41 Ca present at that time and location is uncertain. Strong heating of the precursor occurred ~0.5 Myr after the initial condensation, leading to total melting accompanied by extensive distillation (losing Mg, Si, and other moderately volatile elements) resulting in a stoichiometrically pure hibonite crystal with strongly mass fractionated O, Ca, and Ti isotope compositions and an extreme Ce depletion relative to other REEs. Here we report the results of Li isotope analyses of HIDALGO and discuss the irradiation history of this inclusion.

Meteorite↗
DOE OSTI2020

Materials Data on Ca3(GaNi)4 by Materials Project

Ca3(NiGa)4 crystallizes in the cubic I-43m space group. The structure is three-dimensional. Ca is bonded in a 12-coordinate geometry to four equivalent Ni and eight equivalent Ga atoms. All Ca–Ni bond lengths are 3.07 Å. There are four shorter (3.04 Å) and four longer (3.50 Å) Ca–Ga bond lengths. Ni is bonded in a 10-coordinate geometry to three equivalent Ca, three equivalent Ni, and four equivalent Ga atoms. All Ni–Ni bond lengths are 2.57 Å. There are one shorter (2.34 Å) and three longer (2.47 Å) Ni–Ga bond lengths. Ga is bonded in a 7-coordinate geometry to six equivalent Ca and four equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GaNi by Materials Project

NiGa is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ni is bonded in a body-centered cubic geometry to eight equivalent Ga atoms. All Ni–Ga bond lengths are 2.52 Å. Ga is bonded in a body-centered cubic geometry to eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La3(GaNi)2 by Materials Project

La3Ni2Ga2 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent La sites. In the first La site, La is bonded in a 9-coordinate geometry to four equivalent Ni and five Ga atoms. All La–Ni bond lengths are 3.20 Å. There are a spread of La–Ga bond distances ranging from 3.07–3.30 Å. In the second La site, La is bonded in a 4-coordinate geometry to four equivalent Ni and five Ga atoms. There are a spread of La–Ni bond distances ranging from 2.82–3.35 Å. There are a spread of La–Ga bond distances ranging from 3.19–3.43 Å. Ni is bonded in a 10-coordinate geometry to six La, one Ni, and three Ga atoms. The Ni–Ni bond length is 2.70 Å. There are a spread of Ni–Ga bond distances ranging from 2.54–2.64 Å. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded in a 9-coordinate geometry to seven La and two equivalent Ni atoms. In the second Ga site, Ga is bonded to eight La and four equivalent Ni atoms to form a mixture of distorted corner, edge, and face-sharing GaLa8Ni4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr3(GaNi)2 by Materials Project

Pr3(NiGa)2 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent Pr sites. In the first Pr site, Pr is bonded in a 4-coordinate geometry to four equivalent Ni and five Ga atoms. There are a spread of Pr–Ni bond distances ranging from 2.83–3.32 Å. There are a spread of Pr–Ga bond distances ranging from 3.12–3.45 Å. In the second Pr site, Pr is bonded in a 9-coordinate geometry to four equivalent Ni and five Ga atoms. There are two shorter (3.14 Å) and two longer (3.16 Å) Pr–Ni bond lengths. There are a spread of Pr–Ga bond distances ranging from 3.08–3.21 Å. Ni is bonded in a 10-coordinate geometry to six Pr, one Ni, and three Ga atoms. The Ni–Ni bond length is 2.70 Å. There are one shorter (2.52 Å) and two longer (2.60 Å) Ni–Ga bond lengths. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded in a 9-coordinate geometry to seven Pr and two equivalent Ni atoms. In the second Ga site, Ga is bonded to eight Pr and four equivalent Ni atoms to form a mixture of distorted face, edge, and corner-sharing GaPr8Ni4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2(GaNi)5 by Materials Project

La2(NiGa)5 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent La sites. In the first La site, La is bonded in a 7-coordinate geometry to eight Ni and five Ga atoms. There are a spread of La–Ni bond distances ranging from 3.07–3.27 Å. There are one shorter (3.22 Å) and four longer (3.40 Å) La–Ga bond lengths. In the second La site, La is bonded in a 1-coordinate geometry to seven Ni and six Ga atoms. There are a spread of La–Ni bond distances ranging from 3.01–3.22 Å. There are two shorter (3.15 Å) and four longer (3.35 Å) La–Ga bond lengths. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a 11-coordinate geometry to three La, two equivalent Ni, and six Ga atoms. Both Ni–Ni bond lengths are 2.47 Å. There are four shorter (2.56 Å) and two longer (2.87 Å) Ni–Ga bond lengths. In the second Ni site, Ni is bonded in a 11-coordinate geometry to three La and five Ga atoms. There are a spread of Ni–Ga bond distances ranging from 2.37–2.57 Å. In the third Ni site, Ni is bonded in a 11-coordinate geometry to three La, one Ni, and four equivalent Ga atoms. There are two shorter (2.42 Å) and two longer (2.54 Å) Ni–Ga bond lengths. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded in a 12-coordinate geometry to two La, five Ni, and three Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.54–2.65 Å. In the second Ga site, Ga is bonded in a 2-coordinate geometry to three La, four Ni, and four equivalent Ga atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2002

Dar Al Gani 872: Yet Another Eucrite, Yet Another Lesson to Learn?

We present chemical and mineralogical data on a new monomict basaltic eucrite recovered from Libya. In contrast to most other eucrites, it exhibits high shock features, unusually heterogeneous exsolution of pigeonite, and interesting melt pockets. Additional information is contained in the original extended abstract.

Patzer, A.↗
NASA NTRS1993

Geologic mapping of Northern Atla Regio on Venus: Preliminary data

The Northern part of Atla Regio within the frame of C1-formate Magellan photo map 15N197 was mapped geologically at scale 1:8,000,000. This is a part of Russia's contribution into C1 geologic mapping efforts. The map is reproduced here being reduced about twice. The map shows that the Northern Atla area is predominantly a volcanic plain with numerous volcanic features: shield volcanoes, domes and hills with various morphology, corona-like constructions, radar bright and dark spots often with flow-like outlines. Relatively small areas of tessera occurred in the area are mainly semi-flooded with the plain material. Tesserae are considered to be the oldest terrains within the map sheet. There are many lineated terrains in the region. They are interpreted as the old, almost-buried tesserae (those with crossed lineaments) or partly buried ridge belts (those with parallel lineaments). These lineated terrains have an intermediate age between the young volcanic plains and the old tessera areas. Two prominent high volcanic shields are located within the region - Ozza Mons and Sapas Mona. The most prominent structure in Northern Atla is Ganis Chasma rift. The rift cuts volcanic plain and is considered to be under formation during approximately the same time with Ozza Mons shield. Ganis Chasma rift valley is highly fractured and bounded with fault scarps. Rift shoulder uplifts are typical for Ganis Chasma. There are few relatively young volcanic features inside the rift valley. The analysis of fracturing and rift valley geometry shows the rift originated due to 5-10 percent crustal extention followed by the crustal subsidence. The age sequence summary for the main terrain types in the region is (from older to younger ones): tesserae; lineated terrains with crossed lineaments; lineated terrains with parallel lineaments; volcanic plains; and prominent volcanic shields and Ganis Chasma rift valley. The geologic structure of Atla Regio as it appeared now with the Magellan high resolution images is very close to that of Beta Regio. Such conclusion coincide with the earlier ones based on the coarser data.

Nikishin, A. M.↗
NASA NTRS1992

Venus: Preliminary geologic mapping of northern Atla Regio

A preliminary geologic map of C1 sheet 15N197 was compiled according to Magellan data. Northern Atla Regio is dominantly a volcanic plain with numerous volcanic features: radar-bright and -dark flows and spots, shield volcanos, volcanic domes and hills with varied morphology, and coronalike constructions. Tesserae are the oldest terrains semiflooded by plain materials. There are many lineated terrains on this territory. They are interpreted as old, partly buried ridge belts. Lineated terrains have intermediate age between young plains and old tesserae. Ozza Mons and Sapas Mons are the high shield volcanos. The prominent structure of northern Atla Regio is Ganis Chasma rift. The rift dissected the volcanic plain and evolved nearly contemporaneously with Ozza Mons shield volcano. Ganis Chasma rift valley is highly fractured and bounded by fault scarps. There are a few relatively young volcanic features in the rift valley. The rift originated due to 5-10 percent crustal extension and crustal subsidence according to analysis of fracturing and rift valley geometry. Ganis Chasma is characterized by rift shoulder uplifts. Geological structures of Alta Regio and Beta Regio are very similar as assumed earlier.

Nikishin, A. M.↗