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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Sm(NiSn)2 by Materials Project

Sm(NiSn)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight equivalent Ni and eight equivalent Sn atoms. All Sm–Ni bond lengths are 3.42 Å. All Sm–Sn bond lengths are 3.42 Å. Ni is bonded in a 4-coordinate geometry to four equivalent Sm and four equivalent Sn atoms. All Ni–Sn bond lengths are 2.51 Å. Sn is bonded in a 9-coordinate geometry to four equivalent Sm, four equivalent Ni, and one Sn atom. The Sn–Sn bond length is 2.83 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(ClO4)3 by Materials Project

Sm(O4Cl)3 crystallizes in the trigonal R3c space group. The structure is three-dimensional. Sm is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Sm–O bond distances ranging from 2.42–2.52 Å. There are four inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one Sm 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 Sm 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 Sm 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 Sm(Mg4Al3)4 by Materials Project

Sm(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 10-coordinate geometry to three equivalent Mg, one Sm, and six equivalent Al atoms. All Mg–Mg bond lengths are 3.02 Å. The Mg–Sm bond length is 3.29 Å. All Mg–Al bond lengths are 3.18 Å. In the second Mg site, Mg is bonded in a 12-coordinate geometry to seven Mg and five equivalent Al atoms. There are two shorter (3.10 Å) and four longer (3.17 Å) Mg–Mg bond lengths. There are a spread of Mg–Al bond distances ranging from 2.85–3.17 Å. Sm is bonded in a 12-coordinate geometry to four equivalent Mg and twelve equivalent Al atoms. All Sm–Al bond lengths are 3.24 Å. Al is bonded in a 11-coordinate geometry to seven Mg, one Sm, and three equivalent Al atoms. There are one shorter (2.72 Å) and two longer (2.80 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(ClO)3 by Materials Project

SmOCl3O2 crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of four hydrogen peroxide molecules and two SmOCl3 sheets oriented in the (0, 0, 1) direction. In each SmOCl3 sheet, Sm is bonded in a 7-coordinate geometry to two equivalent O and five Cl atoms. There are one shorter (2.34 Å) and one longer (2.46 Å) Sm–O bond lengths. There are a spread of Sm–Cl bond distances ranging from 2.61–2.86 Å. O is bonded in a linear geometry to two equivalent Sm atoms. There are two inequivalent Cl sites. In the first Cl site, Cl is bonded in a water-like geometry to two equivalent Sm atoms. In the second Cl site, Cl is bonded in a single-bond geometry to one Sm atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(Ge2Rh3)2 by Materials Project

Sm(Rh3Ge2)2 crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Sm is bonded to six equivalent Rh and six equivalent Ge atoms to form face-sharing SmGe6Rh6 cuboctahedra. All Sm–Rh bond lengths are 3.17 Å. All Sm–Ge bond lengths are 3.14 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 (2.50 Å) and four longer (2.57 Å) Rh–Ge bond lengths. In the second Rh site, Rh is bonded in a 6-coordinate geometry to two equivalent Sm and four Ge atoms. There are two shorter (2.49 Å) and two longer (2.56 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 8-coordinate geometry to two equivalent Sm and six Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(BIr)2 by Materials Project

Sm(IrB)2 is alpha Pu-derived structured and crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Sm is bonded in a 2-coordinate geometry to eight equivalent Ir and six equivalent B atoms. There are four shorter (3.08 Å) and four longer (3.27 Å) Sm–Ir bond lengths. There are two shorter (3.02 Å) and four longer (3.15 Å) Sm–B bond lengths. Ir is bonded in a 4-coordinate geometry to four equivalent Sm and four equivalent B atoms. There are two shorter (2.09 Å) and two longer (2.18 Å) Ir–B bond lengths. B is bonded in a 4-coordinate geometry to three equivalent Sm and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(Sn2Rh)2 by Materials Project

Sm(RhSn2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sm is bonded in a 6-coordinate geometry to six Sn atoms. There are a spread of Sm–Sn bond distances ranging from 3.18–3.22 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 2.71–2.89 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 2.72–2.82 Å. There are four inequivalent Sn sites. In the first Sn site, Sn is bonded in a 6-coordinate geometry to two equivalent Sm and four Rh atoms. In the second Sn site, Sn is bonded in a 5-coordinate geometry to two equivalent Sm and three equivalent Rh atoms. In the third Sn site, Sn is bonded in a 3-coordinate geometry to two equivalent Sm and three equivalent Rh atoms. In the fourth Sn site, Sn is bonded to four Rh atoms to form a mixture of distorted corner and edge-sharing SnRh4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(Re2Si)2 by Materials Project

Sm(Re2Si)2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Sm is bonded in a 6-coordinate geometry to twelve equivalent Re and six equivalent Si atoms. There are four shorter (3.25 Å) and eight longer (3.37 Å) Sm–Re bond lengths. There are four shorter (3.03 Å) and two longer (3.07 Å) Sm–Si bond lengths. Re is bonded to three equivalent Sm, six equivalent Re, and three equivalent Si atoms to form a mixture of distorted corner, edge, and face-sharing ReSm3Re6Si3 cuboctahedra. There are a spread of Re–Re bond distances ranging from 2.63–2.83 Å. There are one shorter (2.46 Å) and two longer (2.58 Å) Re–Si bond lengths. Si is bonded in a 9-coordinate geometry to three equivalent Sm and six equivalent Re atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(ZnGa)2 by Materials Project

Sm(ZnGa)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight equivalent Zn and eight equivalent Ga atoms. All Sm–Zn bond lengths are 3.42 Å. All Sm–Ga bond lengths are 3.20 Å. Zn is bonded to four equivalent Sm and four equivalent Ga atoms to form a mixture of distorted corner, edge, and face-sharing ZnSm4Ga4 tetrahedra. All Zn–Ga bond lengths are 2.56 Å. Ga is bonded in a 9-coordinate geometry to four equivalent Sm, four equivalent Zn, and one Ga atom. The Ga–Ga bond length is 2.46 Å.

36 MATERIALS SCIENCE↗
NASA NTRS2015

Technical Report Series on Global Modeling and Data Assimilation: Soil Moisture Active Passive (SMAP) Project Assessment Report for the Beta-Release L4_SM Data Product - Volume 40

During the post-launch SMAP calibration and validation (Cal/Val) phase there are two objectives for each science data product team: 1) calibrate, verify, and improve the performance of the science algorithm, and 2) validate the accuracy of the science data product as specified in the science requirements and according to the Cal/Val schedule. This report provides an assessment of the SMAP Level 4 Surface and Root Zone Soil Moisture Passive (L4_SM) product specifically for the product's public beta release scheduled for 30 October 2015. The primary objective of the beta release is to allow users to familiarize themselves with the data product before the validated product becomes available. The beta release also allows users to conduct their own assessment of the data and to provide feedback to the L4_SM science data product team. The assessment of the L4_SM data product includes comparisons of SMAP L4_SM soil moisture estimates with in situ soil moisture observations from core validation sites and sparse networks. The assessment further includes a global evaluation of the internal diagnostics from the ensemble-based data assimilation system that is used to generate the L4_SM product. This evaluation focuses on the statistics of the observation-minus-forecast (O-F) residuals and the analysis increments. Together, the core validation site comparisons and the statistics of the assimilation diagnostics are considered primary validation methodologies for the L4_SM product. Comparisons against in situ measurements from regional-scale sparse networks are considered a secondary validation methodology because such in situ measurements are subject to upscaling errors from the point-scale to the grid cell scale of the data product. Based on the limited set of core validation sites, the assessment presented here meets the criteria established by the Committee on Earth Observing Satellites for Stage 1 validation and supports the beta release of the data. The validation against sparse network measurements and the evaluation of the assimilation diagnostics address Stage 2 validation criteria by expanding the assessment to regional and global scales.

ubRMSE↗
DOE OSTI2025

Sm 2 Ru 3 Sn 5 : A Noncentrosymmetric Cubic Member of the Ln 2 M 3 X 5 Family

An optimized synthetic method is presented for Sm 2 Ru 3 Sn 5 and investigate its physical properties and electronic structure. Sm 2 Ru 3 Sn 5 is prepared by arc-melting stoichiometric ratios of the elements and is confirmed by single crystal and powder X-ray diffraction. An antiferromagnetic transition is observed at T N = 3.8 K. A modified Curie-Weiss fit to the data in the range 50–150 K yields a Curie-Weiss temperature: θ CW = −36.6 K and an effective magnetic moment: μ eff = 0.83 μ B , in agreement with a Sm 3+ oxidation state. Field-dependent magnetization up to H = 7 T at 2 K shows a maximum response of 0.06 μ B , which is significantly lower than the expected Sm 3+ saturation moment (0.71 μ B ). Resistivity measurements indicate metallic behavior, and analysis of the magnetic entropy from the heat capacity reveals a doublet ground state due to crystal electric field splitting. The electronic structure and density of states are calculated with density function theory and further supported by the local density approximation with dynamical mean-field theory. Finally, the experimental and computational results highlight localized Sm 3+ moments and suggest a possible interplay between Ruddelman–Kitel–Kasuya–Yosida and Kondo interactions, positioning Sm 2 Ru 3 Sn 5 as a promising material for studying topology and complex physical phenomena.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Minimizing particle aggregation in Sm 2 Fe 17 N 3 powders: A CaO-assisted reduction-diffusion approach

We report a novel synthesis of Sm 2 Fe 17 N 3 powders using a CaO-assisted reduction-diffusion (RD) approach. CaO plays a crucial role during mechanochemical processing – acting both as a dispersant and a surface coating agent, which helps to prevent agglomeration due to sintering of Sm 2 Fe 17 particles during the RD step. Together with the added dispersant, the CaO by-product formed during RD can be easily removed in the washing step resulting in fewer aggregated Sm 2 Fe 17 N 3 particles and lower oxygen contamination in the final product. The impact of varying CaO amounts was examined, and synthesis conditions were optimized to achieve phase-pure Sm 2 Fe 17 N 3 powders with less aggregation of magnetic particles. The powders synthesized with addition of 1 wt% CaO as dispersant exhibited the highest hard-magnetic properties: a coercivity (H c ) of 10.7 kOe and a maximum energy product ((BH) max ) of 17.3 MGOe. By densifying the Sm 2 Fe 17 N 3 powders using high-pressure spark plasma sintering, a bulk magnet with a (BH) max of 21.1 MGOe with 88 % of theoretical density was produced. In conclusion, reducing aggregation of the Sm 2 Fe 17 N 3 increases coercivity and remanence of these magnets.

36 MATERIALS SCIENCE↗
DOE OSTI2024

LITE-SM: A Light Sheet Illuminator Compatible with Super Resolution and Single Molecule Imaging

The LITE-SM (hereinafter referred to as the Tilt-SM) is a light sheet illumination system purpose-built for single molecule (SM) imaging. SM imaging is a fluorescence imaging technique where individual molecules can be tracked in living cells/tissues in real time allowing for unprecedented insights into the intracellular dynamics of these molecules. The innovative all-mirror optical design greatly reduces/eliminates the aberrations that plague lens-based designs. This iteration of the Tilt-SM has significantly better optical performance then its predecessor with over 10x increase in optical power at the sample, allowing for the use of much smaller and more cost-effective lasers then the original Phase 1 system. Excellent STORM imaging as well as SM tracking has been achieved, satisfying the key objectives of this study.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1984

Sm-Nd isotopic evolution of chondrites and achondrites. II

The chondrite data obtained as a result of an investigation of Sm-147-Nd-143 and Sm-146-Nd142 isotope systematics in five chondrites and the Moama and Andra dos Reis (ADOR) achondrites are consistent with previously reported reference values for the chondritic uniform reservoir (CHUR) of 0.511847 and 0.1967. The Nd-143/Nd-144 and Sm-147/Nd-144 values of the bulk chondrites analyzed suggest that the CHUR evolution is known to within 0.5 epsilon-units and 0.15 percent of the CHUR values for the entire history of the solar system. The Sm-146-Nd-142 systematics of ADOR and Moama support the hypothesis that Sm-146 was present in the early solar system, suggesting a high Sm-146/Sm-144 ratio that cannot be explained as a late injection forma supernova, and must instead be due to galactic nucleosynthesis.

Jacobsen, S. B.↗
NASA NTRS1989

The presence of Sm-146 in the early solar system and implications for its nucleosynthesis

A correlation of Nd-142/Nd-144 with Sm-144/Nd-144 in two meteorites which have a large range in Sm-144/Nd-144 in their constituent mineral phases is presented as evidence for the presence of the p-process nucleus Sm-146 in the early solar system and its alpha-decay into Nd-142. The ratio Sm-146/Sm-144 is estimated to be about 0.015 at the time of solar system formation, 4.56 AE ago. It is suggested that the abundance of Sm-146 is compatible with p-proc ess production rate estimates, but not with the production rate for Sm-146 based on a photodisintegration model for the production of p-process nuclides.

Prinzhoffer, A.↗
NASA NTRS2004

Fuel Oxidizer Reaction Products (FORP) Contamination of Service Module (SM) and Release of N-nitrosodimethylamine(NDMA)in a Humid Environment from Crew EVA Suits Contaminated with FORP

The Service Module (SM) is an element of the Russian Segment of the International Space Station (ISS). One of the functions of the SM is to provide attitude control for the ISS using thrusters when the U.S. Control Moment Gyros (CMG's) must be desaturated. Prior to an Extravehicular Activity (EVA) on the Russian Segment, the Docking Compartment (DC1) is depressurized, as it is used as an airlock. When the DC1 is depressurized, the CMG's margin of momentum is insufficient and the SM attitude control thrusters need to fire to desaturate the CMG's. SM roll thruster firings induce contamination onto adjacent surfaces with Fuel Oxidizer Reaction Products (FORP). FORP is composed of both volatile and non-volatile components. One of the components of FORP is the potent carcinogen N-nitrosdimethylamine (NDMA). Since the EVA crewmembers often enter the area surrounding the thrusters for tasks on the aft end of the SM and when translating to other areas of the Russian Segment, the presence of FORP is a concern. This paper will discuss FORP contamination of the SM surfaces, the release of NDMA in a humid environment from crew EVA suits, if they happen to be contaminated with FORP, and the toxicological risk associated with the NDMA release.

Schmidl, William↗
NASA NTRS2011

Sm-Nd Isotopic Studies of Ureilite Novo Urei

Ureilites are ultramafic (harzburgitic) achondrites composed predominantly of olivine and pyroxenes, abundant carbon (graphites and shock-produced diamonds), some metal and sulfides. These rocks probably represent ultramafic mantles of differentiated parent asteroidal bodies. Age determinations of these rocks by Rb-Sr and Sm-Nd methods have been difficult because of their extremely low abundances of these parent-daughter elements. Nevertheless, Sm-Nd isochron ages were reported for Kenna, Goalpara, MET 78008 and PCA 82506 yielding ages of 3.74+/-0.02 Ga, approx.3.7 Ga, 4.09+/-0.08 Ga, 4.23+/-0.06 Ga, respectively [1-4]. These "young" Sm-Nd ages may represent secondary metasomatism events [1] related to impacts [5], as indicated by the similarly young Ar-39-Ar-40 degassing ages of 3.3-4.1 Ga for ureilites Kenna, Novo Urei and Havero [6]. Alternatively, it has been suggested that these rocks may have been contaminated with terrestrial crustal materials and the isochrons do not have any age significance [2,7]. Indications of old approx.4.56 Ga ages for ureilites were reported from the U-Pb and Sm-Nd model ages for MET 78008 [8]. More reliable evidences for old formation ages of ureilites were reported recently using the short-lived chronometers Hf-182-W-182, Al-26-Mg-26 and Mn-53-Cr-53. The deficits of 182W in ureilites suggest the metal-silicate segregation occurred very early, approx.1-2 Ma after CAI [9]. The Al-26-Mg-26 and Mn-53-Cr-53 studies for a feldspathic lithology [10] and the Mn-53-Cr-53 for olivine- and pyroxene-dominant lithologies [11] in ureilites revealed that they crystallized approx.5.4 Ma after CAI, i.e., at 4563.8+/-0.5 Ma relative to D.Orbigny. In this report, we present Sm-Nd isotopic data for a relatively fresh ureilite, Novo Urei, a rare ureilite fall (1886). We compare these data to Sm-Nd data for other ureilites, and discuss Novo Urei's petrogenesis

Shih, C.-Y.↗
NASA NTRS2012

Redetermination of the Sm-Nd Age and Initial (Epsilon)Nd of Lunar Troctolite 76535: Implications for Lunar Crustal Development

Lunar troctolite 76535 is an old lunar rock predating the era of the lunar cataclysmic bombardment, but its radiometrially determined ages have been discordant [1-3]. The most recent multi-chronometer study [4] gave preferred ages of 4226+/-35 Ma and 4236+/-15 Ma from a Pb-207/Pb-206 isochron and an U-Pb upper concordia intercept, resp. We derive an age of 4323+/-64 Ma from Sm-Nd data reported by [4] for the bulk rock and three mineral separates. They derived an age of approx.4.38 Ga from combined Rb-Sr data [3,4] by omitting data for olivine separates. Ar-39-Ar-40 ages of approx.4.2 Ga are summarized by [5]. New Sm-147-Nd-143 data presented here give an age of 4335+/-71 Ma in agreement with the Sm-Nd age from [4], whereas Sm-146-Nd-142 data give a model age T(sub LEW) = 4439+/-22 Ma. Further, initial (Epsilon)Nd-143 for 76535 conforms to the Nd-143 evolution expected in an urKREEP [6] reservoir, consistent with inheritance of urKREEP Sm-Nd systematics via assimilation. We show that urKREEP Sm-Nd systematics require the lunar initial (Epsilon)Nd-143 to exceed the Chondritic Uniform Reservoir (CHUR) value [7], but are consistent with evolution from initial (Epsilon)Nd-143 like that of the HED meteorite parent body as defined by a 4557+/-20 Ma internal isochron for the cumulate eucrites Y-980433 and Y- 980318 [8].

Nyquist, Laurence E.↗