Download or read book Barium Isotopes written by Tristan J. Horner and published by Cambridge University Press. This book was released on 2021-04-22 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the modern marine environment, barium isotope (δ138Ba) variations are primarily driven by barite cycling—barite incorporates 'light' Ba isotopes from solution, rendering the residual Ba reservoir enriched in 'heavy' Ba isotopes by a complementary amount. Since the processes of barite precipitation and dissolution are vertically segregated and spatially heterogeneous, barite cycling drives systematic variations in the barium isotope composition of seawater and sediments. This Element examines these variations; evaluates their global, regional, local, and geological controls; and, explores how δ138Ba can be exploited to constrain the origin of enigmatic sedimentary sulfates and to study marine biogeochemistry over Earth's history.
Download or read book New Barium and Cesium Isotopes written by Seymour Katcoff and published by . This book was released on 1947 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Long lived Barium Isotope written by Seymour Katcoff and published by . This book was released on 1948 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non Traditional Stable Isotopes written by Fang-Zhen Teng and published by Walter de Gruyter GmbH & Co KG. This book was released on 2017-03-06 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) makes it possible to precisely measure non-traditional stable isotopes. This volume reviews the current status of non-traditional isotope geochemistry from analytical, theoretical, and experimental approaches to analysis of natural samples. In particular, important applications to cosmochemistry, high-temperature geochemistry, low-temperature geochemistry, and geobiology are discussed. This volume provides the most comprehensive review on non-traditional isotope geochemistry for students and researchers who are interested in both the theory and applications of non-traditional stable isotope geochemistry.
Download or read book Lithium Isotopes written by Philip A. E. Pogge von Strandmann and published by Cambridge University Press. This book was released on 2021-08-26 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lithium isotopes are a relatively novel tracer of present and past silicate weathering processes. Given that silicate weathering is the primary long-term method by which CO2 is removed from the atmosphere, Li isotope research is going through an exciting phase. We show the weathering processes that fractionate dissolved and sedimentary Li isotope ratios, focusing on weathering intensity and clay formation. We then discuss the carbonate and silicate archive potential of past seawater δ7Li. These archives have been used to examine Li isotope changes across both short and long timescales. The former can demonstrate the rates at which the climate is stabilised from perturbations via weathering, a fundamental piece of the puzzle of the long-term carbon cycle.
Download or read book Energy information data base written by United States. Dept. of Energy. Technical Information Center and published by . This book was released on 1979 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pelagic Barite written by Weiqi Yao and published by Cambridge University Press. This book was released on 2021-01-28 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reconstruction of ocean paleoproductivity and paleochemistry is paramount to understanding global biogeochemical cycles such as the carbon, oxygen and sulfur cycles and the responses of these cycles to changes in climate and tectonics. Paleo-reconstruction involves the application of various tracers that record seawater compositions, which in turn may be used to infer oceanic processes. Several important tracers are incorporated into pelagic barite, an authigenic mineral that forms in the water column. Here we summarize the utility of pelagic barite for the reconstruction of export production and as a recorder of seawater S, O, Sr, Ca and Ba.
Download or read book Radioactive Isotopes of Barium written by Richard Walter Fink and published by . This book was released on 1950 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling Barium Isotopes in Metal poor Stars written by Andrew James Gallagher and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The principal theory concerning the origin of the elements heavier than the Fe-peak, such as Ba, strongly suggest that for old, metal-poor environments, the rapid (r-) process is the most likely path taken in their synthesis, while the slow (s-) process becomes more substantial in younger, more metal-rich stellar populations. In this work I test this theory by evaluating the isotope ratios of Ba. It is understood that Ba consists of seven stable isotopes, five of which are synthesised by the two neutron-capture processes. The two odd isotopes, 135,137Ba, as well as 138Ba are synthesised via both the r- and s-processes while two of the even isotopes, 134,136Ba are synthesised via the s-process only. The relative contribution of the r- and s-process to these isotopes can be understood via nucleosynthesis calculations and is described using the parameter fodd, where fodd = [N (135Ba) + N (137Ba)] /N (Ba). Low values of fodd (~0.11) indicate an s-process regime, while high values of fodd (~0.46) indicate an r-process regime. In the Ba II 4554 A line the even isotopes lie close to the line centre, while the odd isotopes, which are hyperfine split because of their non-zero nuclear spin, lie in the wings of the line. From an analysis of the line profile shape, one can determine whether Ba has been synthesised primarily through the r-process or s-process; a broad, asymmetric line would indicate a high r-process contribution, while a line with a deeper core and shallower wings would indicate a high s-process contribution. Using the radiative transfer code ATLAS, which assumes local thermodynamic equilibrium (LTE) and employs 1-dimensional (1D) KURUCZ06 model atmospheres, I synthesised line profiles for six metal-poor stars: HD140283, HD122563, HD88609, HD84937, BD-04 3208 and BD+26 3578 - for a range of isotope ratios. All six are of sufficiently low metallicity that Ba was expected to have an r-process origin. These were fit to high resolution (R\equiv \lamda/\Delta\lamda = 90 000 - 95 000), high signal-to-noise to the Ba II 4554 A line which has multiple components. In the first test, synthetic spectra were computed using the non local thermodynamic equilibrium (NLTE) radiative transfer code MULTI. The synthetic line profiles were fit to a number of lines in HD140283. Although this technique might have improved the fit in the line core, it was found that such a treatment did not improve upon fitting errors associated with the best fit 1D LTE synthetic profiles. The second test used a 3-dimensional (3D) radiative transfer code (LINFOR3D) that employed 3D, time-dependent atmospheres produced with CO5BOLD. The 3D synthetic pro les were fit to a selection of Fe lines and improvements over the poor fits produced by the 1D LTE synthesis were seen. It was found that the 3D synthesis could almost completely reproduce the line asymmetries seen in the observed stellar spectrum. This result suggests that further work to refine the 3D calculations and synthesis code would be valuable.
Download or read book Beta Decay Studies of Short Lived Barium Isotopes written by Charles Skipwith Bendall and published by . This book was released on 1984 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Lethal Action of X Radiation Stable Isotopes of Fission Elements Sr89 and Ba La 140 Upon Goldfish written by C. L. Prosser and published by . This book was released on 1947 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Subject Headings Used in the Catalogs of the United States Atomic Energy Commission written by and published by . This book was released on 1962 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Subject Headings Used by the USAEC Technical Information Service written by U.S. Atomic Energy Commission and published by . This book was released on 1960 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stable Barium Isotopes Biogeochemical Cycling and Palaeoceanographic Applications written by Yang Yu and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book INIS Reference Series written by and published by . This book was released on 1980 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation of Compounds Labeled with Tritium and Carbon 14 written by Rolf Voges and published by John Wiley & Sons. This book was released on 2009-03-12 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compounds labeled with carbon-14 and tritium are indispensable tools for research in biomedical sciences, discovery and development of pharmaceuticals and agrochemicals. Preparation of Compounds Labeled with Tritium and Carbon-14 is a comprehensive, authoritative and up-to-date discussion of the strategies, synthetic approaches, reactions techniques, and resources for the preparation of compounds labeled with either of these isotopes. A large number of examples are presented for the use of isotopic sources and building blocks in the preparation of labeled target compounds, illustrating the range of possibilities for embedding isotopic labels in selected moieties of complex structures. Topics include: Formulation of synthetic strategies for preparing labeled compounds Isotope exchange methods and synthetic alternatives for preparing tritiated compounds In-depth discussion of carbon-14 building blocks and their utility in synthesis Preparation of enantiomerically pure isotopically labeled compounds Applications of biotransformations Preparation of Compounds Labeled with Tritium and Carbon-14 is an essential guide to the specialist strategies and tactics used by chemists to prepare compounds tagged with theradioactive atoms carbon-14 and tritium.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1973 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
