136 research outputs found
Isotopic and Microstructural Analyses of Opaque Mineral Assemblages and Their Alteration Products Hosted in a Refractory Inclusion
Calcium-aluminum-rich inclusions (CAIs) hosted in primitive meteorites are the oldest solids formed in the Solar System. Some CAIs contain metal nuggets that are complex assemblages of Fe-Ni alloys, along with rare ultra-refractory metals such as platinum group elements (PGEs), and their alteration products such as magnetite, sulfides, and phosphates. Three possible mechanisms proposed to explain the origin of these metal nuggets include condensation in circumstellar settings, condensation in the solar nebula within the CAI-forming region, or crystallization from immiscible metal-silicate melt. However, secondary alteration processes may have also affected some of these assemblages. Additionally, similar metal assemblages observed in chondrules and chondritic matrix indicate that all of these metal nuggets could share common high-temperature origins. These metal assemblages record early Solar System conditions that are reflected in their distinctive chemical composition, mineralogy and microstructures. Here we report a detailed mineralogical, microstructural and oxygen isotopic study of one such metal assemblage hosted in a CAI to understand the physical and chemical settings in which it formed
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Correlated analytical studies of organic material from the Tagish Lake carbonaceous chondrite
We report on correlated studies of organic material using SIMS, FIB-SEM, and TEM
Determination of Interface Atomic Structure and Its Impact on Spin Transport Using Z-Contrast Microscopy and Density-Functional Theory
We combine Z-contrast scanning transmission electron microscopy with
density-functional-theory calculations to determine the atomic structure of the
Fe/AlGaAs interface in spin-polarized light-emitting diodes. A 44% increase in
spin-injection efficiency occurs after a low-temperature anneal, which produces
an ordered, coherent interface consisting of a single atomic plane of
alternating Fe and As atoms. First-principles transport calculations indicate
that the increase in spin-injection efficiency is due to the abruptness and
coherency of the annealed interface.Comment: 16 pages (including cover), 4 figure
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Correlated Microscale Isotope and Scanning Transmission X-Ray Analyses of Isotopically Anomalous Organic Matter from the CR2 Chondrite EET 92042
We discuss correlated examinations of organic matter from the CR2 chondrite EET 92042, using SIMS, STXM and other methods. We found a large, isotopically highly anomalous region of probable presolar origin that is C- and 13C-poor and 15N-rich
Analisis Pengelolaan Agroforestry Dan Kontribusinya Terhadap Perekonomian Masyarakat
Agroforestry is a form of community forestry. Agroforestry management related to the optimization of land use for their daily livesof farmers and in order to conserve natural resources. This study aimed to determine the contribution of agroforestry for house hold incomes in Sitaratoit and Lobulayan Village, Tapanuli Selatan District. The results showed that total community income was Rp. 875.900.000,- per year with details incomes from agroforestry was Rp. 597.000.000,- and income from the outside the utilization of agroforestry products contributed Rp.300.900.000,-. Contribution of agroforestry products for people's income is 63% of total income. Income community outside ofagroforestry such as farmer, trader, public civil servant, pensioner and entrepreneur contribute 37% of total income. This means that agroforestry contributed greatly to the house hold income
Faktor-faktor yang Mempengaruhi Perilaku Ibu Nifas dalam Mengkonsumsi Tuo Nifarö di Kecamatan Lotu Kabupaten Nias Utara
Tuo nifarö istypicalofNiasdrink that contains alcohol that resulted from distillation of cocoa. Tuo nifarö can be utilizedfor many purposes, one of them usedfor post-partum period treatment. The aim of this research is to knowing the determinant of post-partum mother's behavior who consumedtuonfaroin Lotu, District of North Nias. This kind of researchis descriptivequantitative andqualitative approachto completethe required datawith a sample of 52 people. The resultsof research onthe characteristics ofrespondents,59.6% were25-35years and61.5% of respondentshavea loweducation level. 61.5% of post-partummothers have the moderate trust levelson benefit ofconsumingtuo nifarö. In terms ofnormativebelief, theconsumptionof alcoholic beveragessuch astuo nifarö for post-partum mothers is affected bythe role offamiliesand communitiesthatinfluence the post-partum mothersto act. Attitudetowardconsumption of tuo nifarö 53.8% wereatmoderatelevels. In terms ofaction, 55.8% of respondentsconsumealcoholic beveragespostpartum, where82.8% had a loweducational level, 48.3% have the confidenceandgood judgment, and 58.6% at a moderate level, 100% supportedbyfamiliesand89.7% are supportedby the community. 72.4% of respondentshadconsumedblack beer as a substitutefor various reasons. This occasion should be maintained with regard to alcohol content, and health workers need to explore the benefits of taking tuo nifar
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Correlated analyses of D- and 15N-rich carbon grains from CR2 chondrite EET 92042
Extract from introduction: Insoluble organic matter (IOM) and matrix from primitive carbonaceous chondrites carry isotope enrichments (?D?20000', ?15N?3200�) that are comparable to those in interplanetary dust particles [1, this work]. Hence, primitive organics that formed in the protosolar cloud (PSC) – or maybe in the cold outer regions of the protoplanetary disk – survived accretion and planetary processing on the asteroids, the parent bodies of the chondrites
FIB-TEM Investigations of Fe-NI-Sulfides in the CI Chondrites Alais and Orgueil
The CI chondrites are primitive meteorites with bulk compositions matching the solar photosphere for all but the lightest elements. They have been extensively aqueously altered, and are composed primarily of fine-grained phyllosilicate matrix material which is host to carbonates, sulfates, sulfides, and minor amounts of olivine and pyroxene. The alteration, while extensive, is heterogeneous. For example, CI-chondrite cubanite and carbonate grains differ on mm to sub-mm scales, demonstrating multiple aqueous episodes. CI-chondrite variability is also evidenced by degree of brecciation, abundance and size of coarse-grained phyllosilicates, olivine and pyroxene abundance, as well as Ni-content and size of sulfide grains. Our previous work revealed Orgueil sulfide grains with variable Ni-contents, metal:S ratios, crystal structures and textures. We continue to explore the variability of CI-chondrite pyrrhotite (Po, (FeNi)1-xS) and pentlandite (Pn, (Fe,Ni)9S8) grains. We investigate the microstructure of sulfides within and among CI-chondrite meteorites in order to place constraints on the conditions under which they formed
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Secondary ion mass spectrometry and x-ray absorption near-edge structure spectroscopy of isotopically anomalous organic matter from CR1 chondrites GRO 95577
We located interstellar organics from a CR1 chondrite with NanoSIMS and analyzed FIB-extracted sections with XANES. D-rich material appears not associated with a functional group, whereas 15N-rich matter shows some affinity to nitrile functionality
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