Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Cd(IN)4”

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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Nd2CdS4 by Materials Project

Nd2CdS4 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Nd3+ is bonded in a 8-coordinate geometry to eight equivalent S2- atoms. There are a spread of Nd–S bond distances ranging from 2.81–3.26 Å. Cd2+ is bonded in a 4-coordinate geometry to eight equivalent S2- atoms. There are four shorter (2.71 Å) and four longer (3.28 Å) Cd–S bond lengths. S2- is bonded in a 6-coordinate geometry to four equivalent Nd3+ and two equivalent Cd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2CdTe4 by Materials Project

La2CdTe4 is Magnesium tetraboride-derived structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. La3+ is bonded in a 8-coordinate geometry to eight equivalent Te2- atoms. There are a spread of La–Te bond distances ranging from 3.17–3.60 Å. Cd2+ is bonded in a 4-coordinate geometry to eight equivalent Te2- atoms. There are four shorter (3.02 Å) and four longer (3.70 Å) Cd–Te bond lengths. Te2- is bonded in a 6-coordinate geometry to four equivalent La3+ and two equivalent Cd2+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1997

A SPDS Node to Support the Systematic Interpretation of Cosmic Ray Data

The purpose of this project was to establish and maintain a Space Physics Data System (SPDS) node that supports the analysis and interpretation of current and future galactic cosmic ray (GCR) measurements by (1) providing on-line databases relevant to GCR propagation studies; (2) providing other on-line services, such as anonymous FTP access, mail list service and pointers to e-mail address books, to support the cosmic ray community; (3) providing a mechanism for those in the community who might wish to submit similar contributions for public access; (4) maintaining the node to assure that the databases remain current; and (5) investigating other possibilities, such as CD-ROM, for public dissemination of the data products. Shortly after the original grant to support these activities was established at Louisiana State University a detailed study of alternate choices for the node hardware was initiated. The chosen hardware was an Apple Workgroup Server 9150/120 consisting of a 120 MHz PowerPC 601 processor, 32 MB of memory, two I GB disks and one 2 GB disk. This hardware was ordered and installed and has been operating reliably ever since. A preliminary version of the database server was available during the first year effort and was used as part of the very successful SPDS demonstration during the Rome, Italy International Cosmic Ray Conference. For this server version we were able to establish the html and anonymous FTP server software, develop a Web page structure which can be easily modified to include new items, provide an on-line database of charge changing total cross sections, include the cross section prediction software of Silberberg & Tsao as well as Webber, Kish and Schrier for download access, and provide an on-line bibliography of the cross section measurement references by the Transport Collaboration. The preliminary version of this SPDS Cosmic Ray node was examined by members of the C&H SPDS committee and returned comments were used to refine the implementation.

Source record↗
NASA NTRS1999

Psychological Selection of NASA Astronauts for International Space Station Missions

During the relatively short-duration Space Shuffle missions, a psychological support program for the astronauts has not been required. Such missions primarily require providing occasional communication with family members by means of audio, video or e-mail, and some diversions such as CD players. During the NASA-Mir Program, conducted from March 1995 through June 1998, mission duration increased to 4-6 months. As a result of these changes it was necessary for NASA to establish an operational Human Behavior and Performance Group (HBPG) to develop and implement a comprehensive program of psychological support. The Mir experience provided the opportunity to develop and implement a psychological support program for long-duration space missions. Many factors influence the support program, including individual preferences, mission duration, and environmental factors such as habitable and personal areas. Lessons learned from the Mir experience are being applied to improve the ISS psychological support program plan. This presentation will address which includes various preflight, in-flight, and post-flight support activities and tools that NASA's HBPG will provide to astronauts and their families for ISS missions.

VanderArk, Steve↗
NASA NTRS2000

A kinetic estimate of the free aldehyde content of aldoses

The relative free aldehyde content of eight hexoses and four pentoses has been estimated within about 10% from the rate constants for their reaction with urazole (1,2,4-triazole-3,5-dione). These values of the percent free aldehyde are in agreement with those estimated from CD measurements, but are more accurate. The relative free aldehyde contents for the aldoses were then correlated to various literature NMR measurements to obtain the absolute values. This procedure was also done for three deoxyaldoses, which react much more rapidly than can be accounted for by the free aldehyde content. This difference in reactivity between aldoses and deoxyaldoses is due to the inductive effect of the H versus the OH on C-2'. This may help explain why deoxyribonucleosides hydrolyze much more rapidly than ribonucleosides.

Non-NASA Center↗
DOE OSTI2020

Materials Data on KCdCl3 by Materials Project

KCdCl3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to eight Cl1- atoms. There are a spread of K–Cl bond distances ranging from 3.28–3.54 Å. Cd2+ is bonded to six Cl1- atoms to form edge-sharing CdCl6 octahedra. There are a spread of Cd–Cl bond distances ranging from 2.55–2.75 Å. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 4-coordinate geometry to one K1+ and three equivalent Cd2+ atoms. In the second Cl1- site, Cl1- is bonded in a 5-coordinate geometry to three equivalent K1+ and two equivalent Cd2+ atoms. In the third Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four equivalent K1+ and one Cd2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbV3Cd4O12 by Materials Project

RbV3Cd4O12 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Rb1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Rb–O bond distances ranging from 2.80–3.44 Å. There are three inequivalent V5+ sites. In the first V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share corners with four CdO6 octahedra and corners with two equivalent CdO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 53–61°. There are a spread of V–O bond distances ranging from 1.74–1.78 Å. In the second V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share corners with four CdO6 octahedra and corners with two equivalent CdO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 40–66°. There are a spread of V–O bond distances ranging from 1.72–1.78 Å. In the third V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share corners with four CdO6 octahedra and corners with two equivalent CdO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 39–65°. There are a spread of V–O bond distances ranging from 1.71–1.81 Å. There are four inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share corners with six VO4 tetrahedra and edges with two CdO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.36–2.41 Å. In the second Cd2+ site, Cd2+ is bonded to six O2- atoms to form CdO6 octahedra that share corners with six VO4 tetrahedra, an edgeedge with one CdO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Cd–O bond distances ranging from 2.27–2.33 Å. In the third Cd2+ site, Cd2+ is bonded to six O2- atoms to form CdO6 octahedra that share corners with six VO4 tetrahedra, an edgeedge with one CdO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Cd–O bond distances ranging from 2.25–2.34 Å. In the fourth Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.31–2.92 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Rb1+, one V5+, and one Cd2+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Rb1+, one V5+, and one Cd2+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one V5+ and three Cd2+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one V5+ and two Cd2+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one V5+, and two Cd2+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one V5+, and two Cd2+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one V5+, and two Cd2+ atoms. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one V5+, and two Cd2+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one V5+ and two Cd2+ atoms. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to one V5+ and three Cd2+ atoms. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one V5+, and two Cd2+ atoms. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one V5+, and two Cd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbCdBr3 by Materials Project

RbCdBr3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Rb1+ is bonded in a 9-coordinate geometry to eight Br1- atoms. There are a spread of Rb–Br bond distances ranging from 3.55–3.75 Å. Cd2+ is bonded to six Br1- atoms to form edge-sharing CdBr6 octahedra. There are a spread of Cd–Br bond distances ranging from 2.69–2.92 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 4-coordinate geometry to one Rb1+ and three equivalent Cd2+ atoms. In the second Br1- site, Br1- is bonded in a 5-coordinate geometry to three equivalent Rb1+ and two equivalent Cd2+ atoms. In the third Br1- site, Br1- is bonded in a 5-coordinate geometry to four equivalent Rb1+ and one Cd2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Modification at the C2'-O-Position with 2-Methylbenzothiophene Induces Unique Structural Changes and Thermal Transitions on Duplexes of RNA and DNA

Oligonucleotides can be chemically modified for a variety of applications that include their use as biomaterials, in therapeutics, or as tools to understand biochemical processes, among others. This work focuses on the functionalization of oligonucleotides of RNA and DNA (12- or 14-nucleotides long) with methylbenzothiophene (BT), at the C2'-O-position, which led to unique structural features. Circular dichroism (CD) analyses showed that positioning the BT units on one strand led to significant thermal destabilization, while duplexes where each strand contained 4-BT rings formed a distinct arrangement with cooperativity/interactions among the modifications (evidenced from the appearance of a band with positive ellipticity at 235 nm). Interestingly, the structural arrays displayed increased duplex stabilization (>10 °C higher than the canonical analogue) as a function of [Na + ] with an unexpected structural rearrangement at temperatures above 50 °C. Density functional theory–polarizable continuum model (DFT-PCM) calculations were carried out, and the analyses were in agreement with induced structural changes as a function of salt content. A model was proposed where the hydrophobic surface allows for an internal nucleobase rearrangement into a more thermodynamically stable structure, before undergoing full denaturation, with increased heat. While this behavior is not common, B- to Z-form duplex transitions can occur and are dependent on parameters that were probed in this work, i.e., temperature, nature of modification, or ionic content. To take advantage of this phenomenon, we probed the ability of the modified duplexes to be recognized by Zα (an RNA binding protein that targets Z-form RNA) via electrophoretic analysis and CD. Interestingly, the protein did not bind to canonical duplexes of DNA or RNA; however, it recognized the modified duplexes, in a [monovalent/divalent salt] dependent manner. Overall, the findings describe methodology to attain unique structural motifs of modified duplexes of DNA or RNA, and control their behavior as a function of salt concentration. While their affinity to RNA binding proteins, and the corresponding mechanism of action, requires further exploration, the tunable properties can be of potential use to study this, and other, types of modifications. The novel arrays that formed, under the conditions described herein, provide a useful way to explore the structure and behavior of modified oligonucleotides, in general.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Al2Cd3(SiO4)3 by Materials Project

Cd3Al2(SiO4)3 is Esseneite-like structured and crystallizes in the cubic Ia-3d space group. The structure is three-dimensional. Cd2+ is bonded in a distorted body-centered cubic geometry to eight equivalent O2- atoms. There are four shorter (2.34 Å) and four longer (2.53 Å) Cd–O bond lengths. Al3+ is bonded to six equivalent O2- atoms to form AlO6 octahedra that share corners with six equivalent SiO4 tetrahedra. All Al–O bond lengths are 1.93 Å. Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 43°. All Si–O bond lengths are 1.66 Å. O2- is bonded in a 4-coordinate geometry to two equivalent Cd2+, one Al3+, and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al2Cd3(GeO4)3 by Materials Project

Cd3Al2(GeO4)3 crystallizes in the cubic Ia-3d space group. The structure is three-dimensional. Cd2+ is bonded in a distorted body-centered cubic geometry to eight equivalent O2- atoms. There are four shorter (2.36 Å) and four longer (2.54 Å) Cd–O bond lengths. Al3+ is bonded to six equivalent O2- atoms to form AlO6 octahedra that share corners with six equivalent GeO4 tetrahedra. All Al–O bond lengths are 1.94 Å. Ge4+ is bonded to four equivalent O2- atoms to form GeO4 tetrahedra that share corners with four equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 46°. All Ge–O bond lengths are 1.78 Å. O2- is bonded in a 4-coordinate geometry to two equivalent Cd2+, one Al3+, and one Ge4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NdTiCdSbO7 by Materials Project

NdTiCdSbO7 crystallizes in the tetragonal P4_122 space group. The structure is three-dimensional. Nd3+ is bonded to eight O2- atoms to form distorted NdO8 hexagonal bipyramids that share edges with two equivalent NdO8 hexagonal bipyramids, edges with four equivalent CdO8 hexagonal bipyramids, edges with two equivalent SbO6 octahedra, and edges with four equivalent TiO6 octahedra. There are a spread of Nd–O bond distances ranging from 2.32–2.66 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four equivalent SbO6 octahedra, edges with two equivalent CdO8 hexagonal bipyramids, and edges with four equivalent NdO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 44–45°. There are a spread of Ti–O bond distances ranging from 1.95–2.01 Å. Cd2+ is bonded to eight O2- atoms to form distorted CdO8 hexagonal bipyramids that share edges with two equivalent CdO8 hexagonal bipyramids, edges with four equivalent NdO8 hexagonal bipyramids, edges with two equivalent TiO6 octahedra, and edges with four equivalent SbO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.20–2.74 Å. Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with two equivalent SbO6 octahedra, corners with four equivalent TiO6 octahedra, edges with two equivalent NdO8 hexagonal bipyramids, and edges with four equivalent CdO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 44–46°. There are a spread of Sb–O bond distances ranging from 1.99–2.03 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Nd3+ and two equivalent Cd2+ atoms to form corner-sharing ONd2Cd2 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Nd3+, one Ti4+, one Cd2+, and one Sb5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Nd3+ and two equivalent Ti4+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Nd3+, one Ti4+, one Cd2+, and one Sb5+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Cd2+ and two equivalent Sb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdTiCdSbO7 by Materials Project

GdTiCdSbO7 crystallizes in the tetragonal P4_122 space group. The structure is three-dimensional. Gd3+ is bonded to eight O2- atoms to form distorted GdO8 hexagonal bipyramids that share edges with two equivalent GdO8 hexagonal bipyramids, edges with four equivalent CdO8 hexagonal bipyramids, edges with two equivalent SbO6 octahedra, and edges with four equivalent TiO6 octahedra. There are a spread of Gd–O bond distances ranging from 2.26–2.66 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four equivalent SbO6 octahedra, edges with two equivalent CdO8 hexagonal bipyramids, and edges with four equivalent GdO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 44–45°. There are a spread of Ti–O bond distances ranging from 1.93–2.01 Å. Cd2+ is bonded to eight O2- atoms to form distorted CdO8 hexagonal bipyramids that share edges with two equivalent CdO8 hexagonal bipyramids, edges with four equivalent GdO8 hexagonal bipyramids, edges with two equivalent TiO6 octahedra, and edges with four equivalent SbO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.23–2.69 Å. Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with two equivalent SbO6 octahedra, corners with four equivalent TiO6 octahedra, edges with two equivalent GdO8 hexagonal bipyramids, and edges with four equivalent CdO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 45–47°. There are four shorter (1.99 Å) and two longer (2.02 Å) Sb–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Gd3+ and two equivalent Cd2+ atoms to form corner-sharing OGd2Cd2 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Gd3+, one Ti4+, one Cd2+, and one Sb5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Gd3+, one Ti4+, one Cd2+, and one Sb5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Gd3+ and two equivalent Ti4+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Cd2+ and two equivalent Sb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaV4Cd3O12 by Materials Project

NaV4Cd3O12 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–2.67 Å. There are two inequivalent V+4.25+ sites. In the first V+4.25+ site, V+4.25+ is bonded to six O2- atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedra tilt angles range from 23–30°. There are a spread of V–O bond distances ranging from 1.88–2.01 Å. In the second V+4.25+ site, V+4.25+ is bonded to six O2- atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedra tilt angles range from 23–30°. There are a spread of V–O bond distances ranging from 1.88–2.03 Å. There are three inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Cd–O bond distances ranging from 2.25–2.66 Å. In the second Cd2+ site, Cd2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Cd–O bond distances ranging from 2.27–2.67 Å. In the third Cd2+ site, Cd2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Cd–O bond distances ranging from 2.28–2.67 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Na1+, two V+4.25+, and two Cd2+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to one Na1+, two V+4.25+, and two Cd2+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to two V+4.25+ and three Cd2+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to one Na1+, two V+4.25+, and two Cd2+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two equivalent V+4.25+, and one Cd2+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two equivalent V+4.25+, and one Cd2+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent V+4.25+ and two Cd2+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent V+4.25+ and two Cd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Integrated Strategies for Overcoming Resolution Limits in Electron Beam Lithography of Chemically Amplified Resists

Electron beam lithography (EBL) of chemically amplified resists (CARs) faces fundamental challenges, including stochastic electron scattering and acid diffusion, that limit resolution and reproducibility. Using SU-8 as a model CAR, this study systematically investigated complementary strategies to address these challenges, combining multipass exposure, proximity effect correction (PEC) with midrange correction factors, base quencher incorporation, and post-exposure bake (PEB) suppression. Monte Carlo simulations and calibrated PEC modeling revealed that extending the point spread function to include a midrange scattering component significantly improved critical dimension (CD) control across varying pattern densities, correcting deviations that conventional two-term PEC failed to capture. Multipass exposure, particularly 4-pass writing with a 25% offset, redistributed the dose to average stochastic beam and scattering fluctuations, reducing line-width roughness by more than 50% and yielding more uniform nanoscale features. Photoacid confinement was investigated by adding urea as a base quencher, which successfully reduced acid diffusion but introduced substantial sensitivity penalties without improving ultimate resolution or Z-factor performance, underscoring the trade-offs of chemical versus physical confinement. Suppressing PEB most directly minimized acid diffusion, resulting in improved Z-factors and reproducible 30 nm half-pitch dense line/space patterns. Overall, these results demonstrated that PEC with midrange correction, multipass strategies, quencher additives, and PEB-free processing addresses different aspects of the EBL process window and that their integration provides a comprehensive framework for managing stochastic scattering, diffusion, and chemical amplification effects. This framework advances dense nanoscale patterning in CARs and establishes guiding principles for optimizing resist design and process strategies in high-resolution EBL and potentially other advanced lithographies, such as extreme ultraviolet (EUV) lithography.

36 MATERIALS SCIENCE↗
NASA NTRS1972

Chemical fractionations in meteorites. V - Volatile and siderophile elements in achondrites and ocean ridge basalts.

Eighteen achondrites and 4 terrestrial basalts (3 ocean ridge, 1 continental) were analyzed by radiochemical neutron activation analysis for Ag, Au, Bi, Br, Cd, Co, Cs, Cu, Ga, In, Ir, Rb, Se, Tl and Zn. Samples included 7 eucrites, 5 howardites, 2 nakhlites, 2 shergottites, an angrite, and an aubrite. Light and dark portions of the gas-rich meteorites Kapoeta and Pesyanoe were analyzed separately. Nakhlites and shergottites have volatile element abundances similar to those in ocean ridge basalts; eucrites, howardites, and angrites show greater depletions by an order of magnitude and less similar abundance patterns. In terms of a two-component model of planetary accretion, the parent planets contained the following percentages of low-temperature material: eucrites 0.8, nakhlites 38, shergottites 28. Shergottites may be genetically related to L-chondrites. The siderophile element pattern of achondrites resembles that of the moon, but with less extreme depletions.

Laul, J. C.↗
NASA NTRS1992

Marine Magnetic Data Holdings of World Data Center-a for Marine Geology and Geophysics

The World Data Center-A for Marine Geology and Geophysics is co-located with the Marine Geology & Geophysical Data Center, Boulder, CO. Fifteen million digital marine magnetic trackline measurements are managed within the GEOphysical DAta System (GEODAS). The bulk of these data were collected with proton precision magnetometers under Transit Satellite navigational control. Along-track sampling averages about 1 sample per kilometer, while spatial density, a function of ship's track and survey pattern, range from 4 to 0.02 data points/sq. km. In the near future, the entire geophysical data set will be available on CD-ROM. The Marine Geology and Geophysics Division (World Data Center-A for MGG), of the National Geophysical Data Center, handles a broad spectrum of marine geophysical data, including measurements of bathymetry, magnetics, gravity, seismic reflection subbottom profiles, and side-scan images acquired by ships throughout the world's oceans. Digital data encompass the first three, while the latter two are in analog form, recorded on 35mm microfilm. The marine geophysical digital trackline data are contained in the GEODAS data base which includes 11.6 million nautical miles of cruise trackline coverage contributed by more than 70 organizations worldwide. The inventory includes data from 3206 cruises with 33 million digital records and indexing to 5.3 million track miles of analog data on microfilm.

Sharman, George F.↗
NASA NTRS2000

BOREAS TE-23 Map Plot Data

The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-23 (Terrestrial Ecology) team collected map plot data in support of its efforts to characterize and interpret information on canopy architecture and understory cover at the BOREAS tower flux sites and selected auxiliary sites from May to August 1994. Mapped plots (typical dimensions 50 m x 60 m) were set up and characterized at all BOREAS forested tower flux and selected auxiliary sites. Detailed measurement of the mapped plots included: (1) stand characteristics (location, density, basal area); (2) map locations diameter at breast height (DBH) of all trees; (3) detailed geometric measures of a subset of trees (height, crown dimensions); and (4) understory cover maps. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Rich, Paul M.↗