Relevant bibliographies by topics / Hafnium isotope analysis

Academic literature on the topic 'Hafnium isotope analysis'

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Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Hafnium isotope analysis"

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Shamanin, I. V., and M. A. Kazaryan. "Conditions for Population of Energy Levels Inversion when Active Medium Based on Gadolinium Isotopes Gd155 and Gd156 Couple Neutron Pumping." Alternative Energy and Ecology (ISJAEE), no. 16-18 (September 11, 2018): 55–62. http://dx.doi.org/10.15518/isjaee.2018.16-18.055-062.

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The paper theoretically studies the possibility of energy transformation of fast and epithermal neutrons to energy of coherent photon radiation at the expense of a neutron pumping of the active medium formed by nucleus with longliving isomerous states. The channel of the nucleus formation in isomeric state as a daughter nucleus resulting from the nuclear reaction of neutron capture by a lighter nucleus is taken into consideration for the first time. Assessment of neutron flux spectrum parameters providing transition from the main state into one of the excited ones for the nuclei of isotopes54Xe130,10Ne22is made. It was shown that to transit the isotope nuclei into the excited state by forward neutron scattering on the nuclei it is necessary to “select” the isotopes not only with great specific energy of nucleons coupling but also with a small value of the neutron absorption cross section. Moreover, the paper performs the analysis of cross sections dependence of radiative neutron capture by the nuclei of gadolinium isotopes Gd155and Gd156. As a result, the speed of Gd156nuclei formation is stated to exceed the speed of their “burnup” in the neutron flux. It is provided by a unique combination of absorbing properties of two isotopes of gadolinium Gd155 and Gd156 in both thermal and resonance regions of neutron energy. We have formulated the conditions required for making isotope nuclei excited by forward neutron scattering on nuclei and for storing nuclei in excited states. The relation which allows estimating processes parameters of neutron capture by nuclei, formation and decay of nuclei isomeric states is obtained as a result of analytical solution of differential equations system of nuclide kinetics taking into account the decay of nuclei isomeric states. The paper makes the possibility analysis of neutron pumping of the participating medium created by the hafnium isotope nuclei. The properties of hafnium isotopes nuclei is found to do not allow providing conditions for population inversion of energy levels due to the formation of hafnium nuclei in isomeric state Hf178m2in the neutron flux. The paper shows the possibility of excess energy accumulation in the participating medium created by the nuclei of the pair of gadolinium isotopes Gd155and Gd156due to formation and storage of nuclei in isomeric state at radiative neutron capture by the nuclei of the stable isotope with a smaller mass. It is concluded that when the active medium created by gadolinium nuclei is pumped by neutrons with the flux density of the order of 1013cm-2·s-1, the condition of levels population inversion can be achieved in a few tens of seconds. The wave length of the radiation generated by the medium is 0.0006 nm. Sintered ceramics Gd2O3based on enriched in the 155-th isotope of gadolinium can be considered a possible active medium. Thus, there is a possibility of creation of the laser techniques of new generation with the parameters providing its application in pulse power engineering of the future.
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Fisher, Christopher M., John M. Hanchar, Scott D. Samson, Bruno Dhuime, Janne Blichert-Toft, Jeffery D. Vervoort, and Rebecca Lam. "Synthetic zircon doped with hafnium and rare earth elements: A reference material for in situ hafnium isotope analysis." Chemical Geology 286, no. 1-2 (June 2011): 32–47. http://dx.doi.org/10.1016/j.chemgeo.2011.04.013.

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Thirlwall, Matthew F., and Andrew J. Walder. "In situ hafnium isotope ratio analysis of zircon by inductively coupled plasma multiple collector mass spectrometry." Chemical Geology 122, no. 1-4 (May 1995): 241–47. http://dx.doi.org/10.1016/0009-2541(95)00003-5.

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Aufmuth, P., R. Kirsch, A. Steudel, and E. W�bker. "Isotope shift in hafnium I: Parametric analysis,ab initio calculation, and changes in nuclear charge radii." Zeitschrift f�r Physik D Atoms, Molecules and Clusters 7, no. 2 (June 1987): 153–59. http://dx.doi.org/10.1007/bf01384581.

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Trešl, Ivan, Oto Mestek, and Miloslav Suchánek. "The Isotope-Dilution Determination of Platinum in Soil by Inductively Coupled Plasma Mass Spectrometry." Collection of Czechoslovak Chemical Communications 65, no. 12 (2000): 1875–87. http://dx.doi.org/10.1135/cccc20001875.

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A method of the determination of trace amounts of platinum in soils has been developed and validated. Samples were ignited, spiked by 198Pt and decomposed by acid digestion (HF-HClO4, HCl-HNO3). Platinum was separated from the matrix by tellurium coprecipitation (recovery 55-87%) and its content was calculated by the (194Pt + 195Pt + 196Pt)/198Pt ratio measurement. In spite of the separation step (hafnium and tungsten recovery below 1%), residual spectral interference caused by HfO+ ions was observed. This interference as well as that of 198Hg were removed by mathematical correction. Accuracy of the method was confirmed by analysis of certified reference material and by the standard addition method. Detection limit of the method was 0.08 ng g-1 Pt. It was found out that the main component of the standard uncertainty of results was sampling uncertainty. Analysis of soil samples taken in the neighbourhood of Hřensko (Northern Bohemia) showed high platinum contents near the road with heavy traffic.
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Sialini, P., P. Sajdl, V. Havránek, and V. Vrtílková. "Study of diffusion processes in the oxide layer of zirconium alloys." Koroze a ochrana materialu 60, no. 1 (March 1, 2016): 1–5. http://dx.doi.org/10.1515/kom-2016-0004.

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Abstract In the active zone of a nuclear reactor where zirconium alloys are used as a coating material, this material is subject to various harmful impacts. During water decomposition reactions, hydrogen and oxygen are evolved that may diffuse through the oxidic layer either through zirconium dioxide (ZrO2) crystals or along ZrO2 grains. The diffusion mechanism can be studied using the Ion Beam Analysis (IBA) method where nuclear reaction 18O(p,α)15N is used. A tube made of zirconium alloy E110 (with 1 wt. % of Nb) was used for making samples that were pre-exposed in UJP PRAHA a.s. and subsequently exposed to isotopically cleansed environment of H2 18O medium in an autoclave. The samples were analysed with gravimetric methods and IBA methods performed at the electrostatic particle accelerator Tandetron 4130 MC in the Nucler Physics Institute of the CAS, Řež. With IBA methods, the overall thicknesses of corrosion layers on the samples, element composition of the alloy and distribution of oxygen isotope 18O in the corrosion layer and its penetration in the alloy were identified. The retrieved data shows at the oxygen diffusion along ZrO2 grains because there are two peaks of 18O isotope concentrations in the corrosion layer. These peaks occur at the environment-oxide and oxide-metal interface. The element analysis identified the presence of undesirable hafnium.
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Nasdala, Lutz, Fernando Corfu, John W. Valley, Michael J. Spicuzza, Fu-Yuan Wu, Qiu-Li Li, Yue-Heng Yang, et al. "Zircon M127 - A Homogeneous Reference Material for SIMS U-Pb Geochronology Combined with Hafnium, Oxygen and, Potentially, Lithium Isotope Analysis." Geostandards and Geoanalytical Research 40, no. 4 (July 16, 2016): 457–75. http://dx.doi.org/10.1111/ggr.12123.

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Choi, Min Seok, Chang-Sik Cheong, Jeongmin Kim, and Hyung Seon Shin. "Hafnium isotope analysis of mixed standard solutions by multi-collector inductively coupled plasma mass spectrometry: an evaluation of isobaric interference corrections." Journal of Analytical Science and Technology 4, no. 1 (2013): 1. http://dx.doi.org/10.1186/2093-3371-4-1.

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Brown, M., C. L. Kirkland, and T. E. Johnson. "Evolution of geodynamics since the Archean: Significant change at the dawn of the Phanerozoic." Geology 48, no. 5 (February 27, 2020): 488–92. http://dx.doi.org/10.1130/g47417.1.

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Abstract A time-series analysis of thermobaric ratios (temperature/pressure [T/P]) for Paleoarchean to Cenozoic metamorphic rocks identified significant shifts in mean T/P that may be related to secular change in the geodynamics on Earth. Thermobaric ratios showed significant (>95% confidence) change points at 1910, 902, 540, and 515 Ma, recording drops in mean T/P, and at 1830, 604, and 525 Ma, recording rises in mean T/P. Highest mean T/P occurred during the Mesoproterozoic, and lowest mean T/P occurred from the Cambrian to the Oligocene. Correlated changes were seen between T/P and global data sets of time-constrained hafnium (Hf) and oxygen (O) isotope compositions in zircon. The range of correlated variation in T/P, Hf, and O was larger during the formation of Rodinia than Columbia. Large changes and a wide range for these variables continued through the Phanerozoic, during which a statistically significant 83 m.y. frequency of T/P excursions recorded the high tempo of orogenic activity associated with the separation, migration, and accretion of continental terranes during the formation of Pangea. Since the early Tonian, the decreasing mean T/P of metamorphism, widespread appearance of blueschist and ultrahigh-pressure metamorphism, and wide fluctuations in Hf and O isotope compositions document a change to the modern plate-tectonic regime, characterized by widespread continental subduction and deeper slab breakoff than in the Proterozoic.
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Rodríguez-Castrillón, José Ángel, Mariella Moldovan, and J. Ignacio García Alonso. "Internal correction of hafnium oxide spectral interferences and mass bias in the determination of platinum in environmental samples using isotope dilution analysis." Analytical and Bioanalytical Chemistry 394, no. 1 (March 14, 2009): 351–62. http://dx.doi.org/10.1007/s00216-009-2681-4.

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Dissertations / Theses on the topic "Hafnium isotope analysis"

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Barovich, Karin Marie. "Behavior of lutetium-hafnium, samarium-neodymium and rubidium-strontium isotopic systems during processes affecting continental crust." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185602.

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Combined Lu-Hf, Sm-Nd and Rb-Sr isotopic studies of continental crustal rocks were undertaken to assess the relative effects of secondary crustal processes on isotopic systematics of whole-rock systems. The processes studied include ductile deformation, and three cases of hydrothermal alteration, involving fluids of varying composition. The Rb-Sr system proved to be easily disturbed during all secondary processes, while Sm-Nd and Lu-Hf systems were, for the most part, resilient. These results show that Nd or Hf isotopic information obtained from old rocks that have undergone typical crustal deformational and alteration events can be counted on to be equally reliable. Nd and Hf isotopic analyses were performed on four suites of Early Archean felsic gneiss complexes from Greenland, Labrador, Swaziland, and Michigan to explore questions associated with Early Archean crustal growth. The Sm-Nd isotopic data yield initial ∊(Nd) values that are mostly consistent with published age data for the suites. Calculations show limited scatter may be attributed to subtle changes in the Sm/Nd ratio or Nd isotopic composition. The Hf isotopic results are more variable and complex than the Nd results. The relevance of the studies on isotopic mobility in the first part of this work is that they have demonstrated that Nd and Hf isotopes are equally resilient during a range of secondary crustal processes. Given the robustness of the Nd isotopic data from the Archean samples, however, it seems unreasonable to attribute the much wider variation in Hf isotopic data to post-Archean isotopic disturbances. Differences in initial Hf isotopic ratios from differing magma sources seem called for. Nd and Hf whole-rock analyses of a Late Archean pristine garnet-bearing granitoid complex from northern Canada point out the importance of garnet in fractionating Lu/Hf ratios, and in developing anomalous ∊(Hf) signatures in potential source regions. Calculations show that even short-lived upper mantle/lower crustal heterogeneities, products of previous partial melting events involving garnet fractionation, can develop the range of positive and negative ∊(Hf) values seen in the Early Archean samples.
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Nasdala, Lutz, Fernando Corfu, John W. Valley, Michael J. Spicuzza, Fu-Yuan Wu, Qiu-Li Li, Yue-Heng Yang, et al. "Zircon M127 - A Homogeneous Reference Material for SIMS U-Pb Geochronology Combined with Hafnium, Oxygen and, Potentially, Lithium Isotope Analysis." WILEY-BLACKWELL, 2016. http://hdl.handle.net/10150/621937.

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In this article, we document a detailed analytical characterisation of zircon M127, a homogeneous 12.7 carat gemstone from Ratnapura, Sri Lanka. Zircon M127 has TIMS-determined mean U-Pb radiogenic isotopic ratios of 0.084743 +/- 0.000027 for Pb-206/U-238 and 0.67676 +/- 0.00023 for Pb-207/U-235 (weighted means, 2s uncertainties). Its Pb-206/U-238 age of 524.36 +/- 0.16 Ma (95% confidence uncertainty) is concordant within the uncertainties of decay constants. The delta O-18 value (determined by laser fluorination) is 8.26 +/- 0.06 parts per thousand VSMOW (2s), and the mean Hf-176/Hf-177 ratio (determined by solution ICP-MS) is 0.282396 +/- 0.000004 (2s). The SIMS-determined delta Li-7 value is -0.6 +/- 0.9 parts per thousand (2s), with a mean mass fraction of 1.0 +/- 0.1 mu g g(-1) Li (2s). Zircon M127 contains similar to 923 mu g g(-1) U. The moderate degree of radiation damage corresponds well with the time-integrated self-irradiation dose of 1.82 x 10(18) alpha events per gram. This observation, and the (U-Th)/He age of 426 +/- 7 Ma (2s), which is typical of unheated Sri Lankan zircon, enable us to exclude any thermal treatment. Zircon M127 is proposed as a reference material for the determination of zircon U-Pb ages by means of SIMS in combination with hafnium and stable isotope (oxygen and potentially also lithium) determination.
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Ware, Timothy Christopher. "Measurement and analysis of the resolved resonance cross sections of the natural hafnium isotopes." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/807/.

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Hafnium is a ductile metallic element with a large neutron absorption cross section. It can be used in reactor control rods to regulate the fission process. The NEA High Priority Request List for nuclear data presents a need for improved characterisation of the hafnium cross section in the resolved resonance region. This thesis presents new resonance cross section parameters for the six natural hafnium isotopes. Cross section measurements, supported by the NUDAME and EUFRAT projects, were performed at the IRMM Geel GELINA time-of-flight facility. Capture experiments were conducted on the 12 m, 28 m and 58 m flight paths using C\(_6\)D\(_6\) detectors and transmission experiments were performed at flight paths of 26 m and 49 m using a \(^6\)Li glass detector. The samples used were metallic natural hafnium discs of various thicknesses and hafnium oxide powders, with differing isotopic enrichments. Data analysis was performed using the least square fitting REFIT code, which was updated during this work. The use of isotopically-enriched samples enabled previously unrecorded resonances to be allocated to the correct isotope. The resulting evaluated data files extend the upper energy limits of the resolved resonance regions for the \(^{174}\)Hf, \(^{176}\)Hf, \(^{177}\)Hf, \(^{178}\)Hf, \(^{179}\)Hf and \(^{180}\)Hf isotopes, relative to the current European recommended evaluation (JEFF3.1), to 250 eV, 3 keV, 1 keV, 3 keV, 1 keV and 3 keV respectively. The natural hafnium resonance integral calculated from the new resonance parameters is 1.2% lower than the integral corresponding to the JEFF3.1 evaluated hafnium data. Comparison of calculated to experimental k-effective values for appropriate zero-power reactor assemblies show improvement over the JEFF3.1 data.
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Falster, G. M. "Geochronological and sedimentological constraints on the evolution of the lower Cuddapah Basin, India." Thesis, 2011. http://hdl.handle.net/2440/96124.

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The Palaeo- to Mesoproterozoic Cuddapah Supergroup was deposited in the Cuddapah Basin, which is one of a number of Proterozoic volcano-sedimentary basins that overlie the Indian Shield. On the south-western margin of the basin, the stratigraphic succession in the basal Papaghni and Chitravati groups is initially composed of gravelly fluvial deposits with dominant sediment input coming from the western foreland. These are succeeded by shallow-water stromatolitic dolomite and shale with a significantly reduced siliciclastic component, and finally by sub-tidal laminated silt and sand. A detailed facies analysis of these rocks suggests that deposition occurred initially in an active extensional setting which subsequently developed into a passive extensional setting. Stable isotope geochemistry of dolomites in the Vempalle Formation of the Papaghni Group indicates that deposition of the formation may initially have occurred in a restricted setting where δ13C varied according to fractionation via environmental processes. Whether the Vempalle Formation was deposited in a shallow marine or lacustrine milieu is equivocal; δ13C values may correlate with the conclusion of the global oceanic “Lomagundi” positive δ13C excursion around 2100 Ma, however, this inference requires the carbonates to have been precipitated in oceanic water, and have retained their primary isotopic signature during pervasive dolomitisation. U-Pb dating of detrital zircon grains from the Gandikota Formation – previously thought to be the uppermost formation of the Chitravati Group – yields a maximum depositional age of 1207 ± 22 Ma. This is significantly younger than intrusive igneous rocks within the Cuddapah Supergroup and it is therefore likely that the Gandikota Formation is part of the overlying Meso- to Neoproterozoic Kurnool Group. The detrital zircon age spectrum of the Gandikota Formation indicates significant sediment input from the east, which is likely to be a result of the thrusting of the Eastern Ghats Belt onto the Eastern Dharwar Craton and a reversal of the prevailing extensional regime in the Cuddapah Basin. A number of authors have proposed a genetic link between the Cuddapah Basin and several other Proterozoic basins of the Indian Shield. This study provides no reason to directly correlate the temporally and spatially distinct basins.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2011
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Conference papers on the topic "Hafnium isotope analysis"

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Counts, John, William H. Craddock, and Jared Gooley. "DEFINING THE HAFNIUM ISOTOPIC SIGNATURE OF THE APPALACHIAN OROGEN THROUGH ANALYSIS OF MODERN FLUVIAL SEDIMENTS." In GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-378540.

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