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Showing 1 to 20 of 1090 for “"Isotopic"”.
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Isotopic study of uranium: determining the isotopic fractionation of uranium during abiotic reduction with iron(II)
… Little work has been done to determine the isotopic fractionation induced by abiotic reduction. This study focuses on determining the isotopic fractionation of uranium during reduction with Fe(II). Time series experiments with aqueous Fe(II) and magnetite (Fe3O4) were conducted with samples …
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Sequential Isotopic Analysis of Ammonite Aptychi
… and biological factors. Previous stable isotopic studies on ammonite aptychi were based on bulk sampling, and thus cannot reveal information about ammonite life history. This thesis reports the first time series δ18O and δ13C values measured in eight ammonite aptychi and assesses their …
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Isotopic Characterization of Illinois Natural Gas
Made available in DSpace on 2014-12-14T07:10:48Z (GMT). No. of bitstreams: 1 7624060.pdf: 8327252 bytes, checksum: f23b529f1eaa156d75059a3256cf8ebe (MD5) Previous issue date: 1976
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Global isotopic signatures of oceanic island basalts
Sr, Nd and Pb isotopic analyses of 477 samples representing 30 islands or island groups, 3 seamounts or seamount chains, 2 oceanic ridges and 1 oceanic plateau [for a total of 36 geographic features] are compiled to form a comprehensive oceanic island basalt [OIB] data set. These samples are …
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The isotopic evolution of the British lithosphere
… Ma, or sediment subduction to account for the isotopic systematics of the slab component.<br></br><br></br>The dioritic primary magma to the Leinster Granite is predominantly derived from juvenile lower crust. The maximum mantle component involved in the diorites' petrogenesis is 30% and the …
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Isotopic studies of selenium in environmental samples.
Selenium has aroused much interest in the last decade. It is an essential trace element for man and animals and has been found to be the cofactor in two enzyme systems. The first, glutathionine peroxidase, acts as an anti-oxidant by destroying peroxides which attack cellular membranes. The second, …
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Isotopic Tracer Studies of Organic Peroxide Decompositions
Made available in DSpace on 2014-12-05T19:38:00Z (GMT). No. of bitstreams: 1 6206130.pdf: 4744222 bytes, checksum: 9d7225c2d543c3ca3c4577b467a576d0 (MD5) Previous issue date: 1962
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Spaces of Isotopic Triangulations of a 2-Cell
Made available in DSpace on 2014-12-09T22:17:59Z (GMT). No. of bitstreams: 1 7105048.pdf: 4185806 bytes, checksum: 1846252767c8d24856dcb89ca51be162 (MD5) Previous issue date: 1970
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Global isotopic signatures of oceanic island basalts / by
Sr, Nd and Pb isotopic analyses of 477 samples representing 30 islands or island groups, 3 seamounts or seamount chains, 2 oceanic ridges and 1 oceanic plateau [for a total of 36 geographic features] are compiled to form a comprehensive oceanic island basalt [OIB] data set. These samples are …
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The strontium isotopic composition and origin of carbonatites
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1962.
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An Isotopic Analysis of Carbon Dynamics in Sphagnum Peat
… dissolved in surface pool water is traced using isotopic analysis as it is oxidised and travels into the interstitial Sphagnum water, through to being photosynthetically captured in α‐cellulose that makes up living Sphagnum, and finally to the carbon stored in layers of peat. Evidence is …
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Advancements in Isotopic Geolocation Tools for Insect Migration Research
… of isotope geolocation and demonstrate how isotopic geolocation tools can advance our understanding of insect migration at the population level. In the first chapter, I test the validity of using ⁸⁷Sr/⁸⁶Sr, lead isotopes, and a suite of 23 metals and metalloids to estimate the natal origins …
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Osmium alkane complexes: Synthesis, characterization, and isotopic labeling studies
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2025-05-01
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Vegetation and microbial determinants of soil carbon isotopic composition
Typically, soil δ¹³C and δ¹⁵N values tend to increase with depth across a wide range of ecosystems. Changes in δ¹³C with depth have been attributed to vegetation changes (i.e. C₃/C₄ shifts), but the similarity in δ¹³C and δ¹⁵N profiles suggest that microbial decomposition may play an important …
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Isotopic systematics and mass transfer in amphibolite-grade mylonites
… possible effects of dynamic metamorphism on the isotopic ages obtained from zircons range from no apparent Pb loss to complete resetting of the isotopic "clock". The two examples presented here represent the two extremes: the mid-Paleozoic, greenschist-grade Rockfish Valley Fault Zone, and the …
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ISOTOPIC CONSTRAINTS ON ATMOSPHERIC MOISTURE TRANSPORT PROCESSES IN SOUTH AMERICA
… exerts a strong influence on Earth's climate. Isotopic ratios in modern water vapor can provide us with insights into low-latitude moisture-transport processes in the modern climate system, recorded in paleoclimate proxy records, and in general circulation models that we rely on to understand …
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Hydrology of Bishop Creek, Inyo County, California: An isotopic analysis
… adverse effects on the riparian community. An isotopic study was employed to better understand the hydrology of the basin, estimate the volume of ground-water input along diverted reaches of Bishop Creek, and determine the sources of water to different tree species at various times of the …
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