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Thèses sur le sujet « Isotopic model »

Auteur : Grafiati

Publié le 10 mars 2023

Mis à jour le 31 juillet 2025

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1

Fomchenko, Anna. ""Expanded" local mode approach and isotopic effect in polyatomic molecules." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS036/document.

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Dans cette thèse, sur la base de l'approche du mode local "étendu" et de la théorie générale de la substitution isotopique, nous obtenons un ensemble de relations analytiques simples entre les paramètres spectrocopiques (fréquences harmoniques, coefficients d'anharmonicité, paramètres rovibrationels, différents types de paramètres d'interaction de Fermi et de Coriolis) des molécules de CH2D2, CH3D et CHD3. Tous ces paramètres sont exprimés en termes de relations simples à partir des paramètres spectroscopiques de la molécule mère CH4. Des calculs tests avec des relations isotopiques montrent q

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2

Burk, David Edward. "Forward model calculations for determining isotopic compositions of materials used in a radiological dispersal device." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2366.

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In the event that a radiological dispersal device (RDD) is detonated in the U.S. or near U.S. interests overseas, it will be crucial that the actors involved in the event can be identified quickly. If irradiated nuclear fuel is used as the dispersion material for the RDD, it will be beneficial for law enforcement officials to quickly identify where the irradiated nuclear fuel originated. One signature which may lead to the identification of the spent fuel origin is the isotopic composition of the RDD debris. The objective of this research was to benchmark a forward model methodology for predic

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3

De, Lurio Jennifer Lynn. "Paleoclimatic significance of glendonite pseudomorphs in the early cretaceous of the Eromanga Basin, Australia : a geochemical and isotopic model /." Title page, abstract and contents only, 1995. http://web4.library.adelaide.edu.au/theses/09SB/09sbd366.pdf.

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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1995.<br>Australian National Grid reference SH/54-5 Marree sheet 1:250000. Includes bibliographical references (leaves 40-54).

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4

Shipley, Niccole Kiyomi. "Isotopic and Petrologic Investigation and Model of Genesis of Large-Volume High-Silica Rhyolites in Arc Environments: Karymshina Caldera, Kamchatka, Russia." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/12187.

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xii, 76 p. ： ill. (some col.)<br>Large-volume calderas are responsible for producing large deposits of rhyolite and high-silica rhyolite, but the mechanisms by which these deposits are produced are still poorly understood. The Kamchatka Peninsula of Russia contains several large calderas and is one of the most volcanically active areas on Earth. Karymshina Caldera, the largest (25 km x 15 km) caldera in Kamchatka, produced an estimated 800 km 3 of high-silica rhyolitic ignimbrites and post-caldera extrusions, which erupted 1.78 and 0.5-0.8 Ma, respectively. SiO2 content ranges from 66.27-71

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5

Fusetti, Luc. "Elaboration of a kinetic model in order to predict the molecular and isotopic composition of natural gas generated during the thermal cracking of hydrocarbons." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/2088.

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The scope of the present study was to validate an approach that could be used to elaborate a model that would predict the δ[superscript]13C of the gases generated during thermal cracking of oil. The attention was focused on C[subscript]14- methylaromatics and alkylaromatics but the entire methodology was demonstrated on one component i.e. 1,2,4-trimethylbenzene.Pyrolysis experiments at temperatures of 395, 425, 450, and 475 °C and at a pressure of 100 bar were performed in order to study the whole range of conversions. All pyrolysis fractions were recovered and quantified. All identified produ

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6

Köten, Muharrem [Verfasser]. "An improved efficiency model for ACE-SWICS : determination of the carbon isotopic ratio 13C, 12C in the solar wind from ACE-SWICS measurements / Muharrem Köten." Kiel : Universitätsbibliothek Kiel, 2009. http://d-nb.info/1019812788/34.

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7

Calippo, Flávio Rizzi. "Sociedade sambaquieira, comunidades marítimas." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/71/71131/tde-23062010-160307/.

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Tendo como referencial teórico abordagens focadas na Arqueologia Marítima (MUCKELROY, 1978; ADAMS, 1998, 2002), na Antropologia Marítima (MALINOWSKI, 1986 [1922]; DIEGUES, 1998) e em estudos de Percepção Ambiental (INGOLD, 2000), buscou-se desenvolver e testar a hipótese de que, embora houvesse uma unidade cultural que permitisse o estabelecimento de uma ampla sociedade sambaquieira, os povos dos sambaquis estariam organizados em comunidades costeiras regionais, as quais teriam se desenvolvido e se organizado em diferentes comunidades marítimas, costeiras e fluviais, em conseqüência dos difere

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8

Di, Hong J. "Application of isotopic dilution methods to the study of the dissolution of phosphate fertilisers of differing solubility in the soil." Lincoln University, 1991. http://hdl.handle.net/10182/1792.

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An injection technique, in which undisturbed soil cores are labelled with ³²P to study dissolution of phosphate fertilisers in the soil, was evaluated in field and glasshouse trials. When ³²P was injected between 0-150 mm depths of the undisturbed soil columns and fertilisers applied at the surface, the amounts of fertiliser P dissolved, as measured by the increases in the exchangeable P pools, were overestimated. Three possible reasons were suggested: (i) the interaction between surface-applied fertiliser, ³²P injected through the whole soil column, and the vertical decline in root density, (

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9

King, Adam C. "The Cressbrook Creek alluvial aquifer system, Southeast Queensland : hydrochemistry and isotopes to determine hydrological processes and response to floods." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/78443/1/Adam_King_Thesis.pdf.

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This study developed an understanding of hydrological processes within the Cressbrook Creek catchment of the upper Brisbane River, in particular for the alluvial aquifers. Those aquifers within the lower catchment are used for intensive irrigation, and have been impacted by long-term drought followed by flooding. The study utilised water chemistry, isotopic characters and hydraulic measurements to determine factors such as recharge, links between creeks and groundwater, and variations in water quality. The catchment-wide study will enable improved management of the local water resources.

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Delavau, Carly J. "Development of precipitation δ18O isoscapes for Canada and application within a tracer-aided hydrological model". Taylor and Francis, American Geophysical Union, 2015. http://hdl.handle.net/1993/31946.

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Delineating spatial patterns of precipitation isotopes (“isoscapes”) is important for studies including the hydrology of terrestrial systems, present and past interpretations of climate, and tracer-aided hydrological modelling, among others. However, the extent to which precipitation isoscapes can be predicted across Canada has not been fully articulated. This thesis combines isotopes in precipitation (δ18Oppt) observations from two regional and one global network to create long term and time series precipitation isoscapes for Canada and the northern United States. Multi-linear regressions of

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11

Cagnon, Benjamin. "Etude fondamentale de la dissolution des silicates amorphes et cristallins : apport à la robustesse des modèles." Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALU012.

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La sureté du stockage géologique des déchets nucléaires de haute activité est un sujet au cœur des grands challenges scientifique et technologique de notre siècle. Ces déchets, issus des combustibles nucléaires, sont vitrifiés et entreposés sur les sites de production (La Hague, Marcoule) en attendant l’ouverture d’un site de stockage définitif. Leur durabilité chimique fait l’objet de nombreux travaux pour évaluer le devenir des radionucléides dans l’environnement. Cette thèse s’inscrit dans cette thématique et repose sur deux axes d'étude. Le premier se focalise sur l’effet du désordre struc

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12

Samper, Calvete F. Javier(Francisco Javier) 1958. "Statistical methods of analyzing hydrochemical, isotopic, and hydrological data from regional aquifers." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/191115.

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This dissertation is concerned with the development of mathematical aquifer models that combine hydrological, hydrochemical and isotopic data. One prerequisite for the construction of such models is that prior information about the variables and parameters be quantified in space and time by appropriate statistical methods. Various techniques using multivariate statistical data analyses and geostatistical methods are examined in this context. The available geostatistical methods are extended to deal with the problem at hand. In particular, a three-dimensional interactive geostatistical package

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13

Nilsson, Lino. "Nitrogen Cycling at Cold Climate Mine Sites in Northen Sweden." Licentiate thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59661.

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High nitrogen discharge from mining sites has been an environmental issue that has been closely studied in the recent years. The environmental effects of high nitrogen discharge are mainly eutrophication, but can also lead to changed species composition and algae blooms. Nitrogen is a highly abundant element and is the most abundant element in the atmosphere, where 78% by volume is present as dinitrogen (N2 ). Nitrogen is present in reduced form in all organic life as ammonium (NH4 + ). Nitrogen is also present in reduced form as nitrate (NO3 - ) or nitrite (NO2 - ) in most aquatic systems. B

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14

PORTOGHESE, CELIA C. P. "Modelagem matematica do comportamento estatico e dinamico dos parametros operacionais de cascatas de separacao isotopica por ultracentrifugacao." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11057.

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Made available in DSpace on 2014-10-09T12:47:35Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:06:35Z (GMT). No. of bitstreams: 1 08365.pdf: 11054143 bytes, checksum: fbcba90b2c7b731c19fd9fe83143485d (MD5)<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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MIGLIAVACCA, SYLVANA C. P. "Modelagem do comportamento separativo de ultracentrifugas via rede neural." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10729.

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Made available in DSpace on 2014-10-09T12:43:24Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T13:56:10Z (GMT). No. of bitstreams: 1 06526.pdf: 11749564 bytes, checksum: 3bdf9fe6bde542868235ac958c48f4f4 (MD5)<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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16

Shergur, Jason Michael. "Investigation of shell model states in exotic odd-A Sb isotopes." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2363.

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Thesis (Ph. D.)--University of Maryland, College Park, 2005.<br>Thesis research directed by: Chemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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17

Jones, Karen. "A biokinetic model for Cesium-137 in the fetus." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/16764.

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18

Semmes, Paul Barksdale. "Core-quasiparticle coupling model calculations as a test of IBA core descriptions of the even-mass Hg isotopes : decay of mass-separated [superscript]203At." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/30906.

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19

Huth, Anne M. Kramer. "Geochemical and isotopic mixing models : two case studies in a snow-dominated and semi-arid environment." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/191260.

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The influence of climate and antecedent moisture conditions on hydrological and biogeochemical fluxes was studied and contrasted in three nested, high-elevation, snowmelt-dominated catchments in the Sierra Nevada, California and one basin-floor, semi-arid catchment in southeastern Arizona. Investigations were completed within a different two-year period at each site, with the second year being climatically different (typically drier) than the first. Spring snowmelt, widespread winter frontal precipitation, and episodic summer rains induce surface water flow in these catchments, though the timi

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20

Millet, Bruno. "Tracer and model constraints on the ventilation of the deep Pacific Ocean." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASJ019.

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L'océan Pacifique représente environ 50% du volume global des océans, ce qui en fait un acteur essentiel des cycles biogéochimiques globaux et de leur réponse aux perturbations. En particulier, l'océan Pacifique profond abrite des réservoirs majeurs de carbone et de nutriments, dont la taille et les variations sont largement contrôlées par les transports physiques de traceurs. Dans cette thèse, nous visons à mieux comprendre et contraindre le transport de traceurs dans l'océan Pacifique profond à travers les états climatiques. Pour cela, nous générons de nouvelles et utilisons d'anciennes obse

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21

Pham, Thuy Van. "Using isotope effects to model transition states for carbocation-nucleophile combination reactions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0003/NQ41271.pdf.

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22

Völpel, Rike [Verfasser], André [Akademischer Betreuer] Paul, Michael [Gutachter] Schulz, and Heiko [Gutachter] Pälike. "Benthic foraminiferal oxygen isotopes during the Last Glacial Maximum and last deglaciation : Paleoceanographic inferences from an isotope-enabled global ocean model / Rike Völpel ; Gutachter: Michael Schulz, Heiko Pälike ; Betreuer: André Paul." Bremen : Staats- und Universitätsbibliothek Bremen, 2018. http://d-nb.info/1171420412/34.

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Goto, Momoko. "Development of a quantitative model for binding cesium to SRS soils." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/16798.

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Rodriguez-Nieva, Joaquin F. (Joaquin Francisco). "Effects of isotope doping on the phonon modes in graphene." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79563.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 41-46).<br>Carbon related systems have attracted a large amount of attention of the science and technology community during the last few decades. In particular, graphene and carbon nanotubes have remarkable properties that have inspired applications in several fields of science and engineering. Despite these properties, creating structurally perfect samples is a difficult objective to achieve. Defects are usu

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Thibon, Fanny. "Chimie des océans au Paléoprotérozoïque." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEN008/document.

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Les conditions oxydantes de la surface terrestre actuelle sont dues à la teneur élevée en dioxygène de l’atmosphère. Au début de l’histoire de la Terre il y a 4.54 milliards d'années (Ga), l’oxygène n’était pas stable dans l’atmosphère. Il a fallu deux épisodes d’augmentation brutale de ce gaz atmosphérique pour qu’il atteigne son niveau actuel : l’un vers 2.4 Ga, nommé le Grand Evènement Oxydant (GOE) qui fait l’objet de ce projet, l’autre 2 milliards d’années plus tard, nommé l’Evènement Oxydant Néo-protérozoïque (NOE). Le GOE est vraisemblablement le résultat de l’émersion généralisée de la

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FRONZI, DAVIDE. "Definition of the hydrogeological conceptual model with an integrated approach in earthquakes-induced changing contexts." Doctoral thesis, Università Politecnica delle Marche, 2022. http://hdl.handle.net/11566/299681.

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La comprensione dei processi di ricarica, di movimento e di immagazzinamento delle acque sotterranee negli acquiferi carbonatici rappresenta una grande sfida per l’idrogeologia. Infatti, questi acquiferi sono ospitati in formazioni geologiche caratterizzate da forti eterogeneità e anisotropie che si possono ripercuotere nelle caratteristiche idrodinamiche del sistema. Questa comprensione diventa tanto più complicata quando si trattano acquiferi ricadenti in aree montuose, ove la complessità geologico-strutturale si unisce a una grande eterogeneità topografica. Quest’ultima può influenzare il r

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Tunaley, Claire. "Integrating high-frequency DOC data, isotopes and modelling to assess flow paths, connectivity and water ages." Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=231260.

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Understanding the spatial and temporal dynamics occurring in headwater catchments enhances our ability to effectively manage the natural and unnatural inputs from the landscape to the stream. DOC is particularly important in northern peat dominated catchments, where concentrations in rivers have been increasing over recent decades. Due to the significant downstream impacts this increase has on the functioning of aquatic ecosystems and the quality of drinking water, it is vital to understand the tight coupling between the landscape and the stream. This study set out to explore the use of integr

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28

Li, Lingwei. "Understanding Antarctic Circumpolar Current Transport at the LGM Using an Isotope-enabled Ocean Model." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555594394056462.

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Tarutina, Tatiana. "Core excitation in the structure and breakup of heavy beryllium isotopes." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/843177/.

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The 14Be nucleus is a good candidate for having a halo structure. When a three- body model is used to calculate the properties of this nucleus, it relies on a knowledge of the potentials involved and hence on the structure of the underlying two-body subsystem 13Be. Previuosly published calculations showed that, in order to describe 13Be and 14Be simultaneously, 13Be had to be either bound, or have a p-shell ground state, which is not consistent with the experimental data. In this thesis 13Be and 14Be are described as one or two neutrons outside a deformed 12Be core. The idea of the method is t

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Husic, Admin. "NUMERICAL MODELING AND ISOTOPE TRACERS TO INVESTIGATE KARST BIOGEOCHEMISTRY AND TRANSPORT PROCESSES." UKnowledge, 2018. https://uknowledge.uky.edu/ce_etds/70.

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This dissertation investigated the physical and biogeochemical processes affecting the source, fate, and transport of sediment, carbon, and nitrogen within a highly-coupled fluviokarst system. Elemental and isotopic datasets were collected at surface and subsurface locations for both dissolved and particulate contaminant phases, new methodology regarding data collection was presented to the karst research community, an in-cave sediment transport model coupling physical transport with elemental and isotopic mass balances of carbon and nitrogen was formulated, pathway and process control on nitr

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Serefiddin, Feride Schwarcz H. P. "Paleoclimate models for western North America as inferred from speleothem isotope records /." *McMaster only, 2003.

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32

Bréant, Camille. "Variabilité régionale de la densification de la neige polaire lors des grandes transitions climatiques." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV104/document.

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Le déphasage entre augmentation de température et augmentation de gaz à effet de serre (GES) dans l'atmosphère lors des grandes transitions climatiques passées est estimé grâce aux mesures effectuées dans les carottes de glace polaires dans la phase glace pour la température et dans la phase gaz (bulles d’air piégées) pour la concentration en GES. Ce déphasage est encore mal contraint et, pour résoudre ce problème, il est nécessaire de mieux comprendre le processus mécanique de transformation de neige en glace près de la surface de la calotte (centaine de mètres supérieurs, le névé). En l'abse

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McClanahan, Kegan N. "Carbon Cycling Dynamics Inferred from Carbon Isotope Sourcing in a Mid-Latitude Karst-Influenced River." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1393.

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As ever-increasing levels of carbon dioxide alter the chemistry of the Earth’s atmosphere, understanding the global carbon cycle becomes increasingly important. A particularly important component is the riverine carbon cycle, as rivers are the primary conduits for dissolved inorganic carbon from terrestrial watersheds to ocean basins. Stable carbon isotopes (13C/12C) were collected weekly and input into the mixing model IsoSource to delineate seasonal carbon sourcing along two nested basins in the upper Green River System, Kentucky. In the more siliciclastic upstream catchment, dissolved inorg

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Leask, Peter John. "Probing nuclear molecular analogue states in carbon, boron and beryllium isotopes." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369340.

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Hart, Rachelle. "Isotopic Evaluation of Carbon Dioxide in Soil Gas in Utah for a More Accurate Input Variable in Groundwater Age Determining Models." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/2248.

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In order to achieve a more accurate input value for groundwater age determining models, δ13CVPDB values for soil gas were evaluated at 50 cm depths in locations throughout Utah in order to define correlations between δ13C and environmental parameters. 16 sites were chosen that exploited large changes in elevation and latitude which provided variations in climate, precipitation, plant community, etc. Gas samples were collected over 1-1½ years, and soil samples were collected at depth during installations. Field and laboratory studies were also used to evaluate CO2 and δ13C change with depth. It

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Renedo, Elizalde Marina. "Sources and fate of methylmercury in the Southern Ocean : use of model seabirds and mercury stable isotopes." Thesis, La Rochelle, 2017. http://www.theses.fr/2017LAROS031/document.

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Malgré leur distance de la pression industrielle, les milieux marins austraux et antarctiques sont contaminés par des polluants globaux, tels que le mercure (Hg), par le transport atmosphérique et les courants océaniques. Jusqu'à présent, les voies de contamination du Hg dans l'Océan Austral restent peu connues, en particulier dans le secteur Indien, et de nouvelles études sont nécessaires pour élucider son devenir et son impact dans ces régions. Les oiseaux marins, en tant que prédateurs supérieurs des chaînes alimentaires marines, sont exposés à des concentrations élevées de méthylmercure (M

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Deng, Jia, Carmody K. McCalley, Steve Frolking, et al. "Adding stable carbon isotopes improves model representation of the role of microbial communities in peatland methane cycling." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/625198.

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Climate change is expected to have significant and uncertain impacts on methane (CH4) emissions from northern peatlands. Biogeochemical models can extrapolate site-specificCH(4) measurements to larger scales and predict responses of CH4 emissions to environmental changes. However, these models include considerable uncertainties and limitations in representing CH4 production, consumption, and transport processes. To improve predictions of CH4 transformations, we incorporated acetate and stable carbon (C) isotopic dynamics associated with CH4 cycling into a biogeochemistry model, DNDC. By includ

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Shang, Zhaorong, and 商照榮. "A study of Ag-110m in aquatic and terrestrial ecosystems and the development of a radioecological model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B29747326.

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Burgett, Claire Margaret. "Green Sea Turtles (Chelonia mydas) in Bermuda Exhibit an Ontogenetic Diet Shift despite Overexploitation of Resources in their Developmental Habitat." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3267.

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Green sea turtles in Bermuda are overgrazing the seagrasses on which later life stages are thought to specialize. I hypothesized that larger green turtles in Bermuda would display individual diet specializations during seagrass scarcity. Stable isotope methods were used to determine the diet composition of green sea turtles from the Bermuda Platform as a function of size class and in turtles captured in successive years. Individual turtles had a wide range of diets, however, the variation in diets was driven by differences among size class rather than within the size classes of larger turtles,

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Meng, Yue. "The Daya Bay Reactor Neutrino Experiment." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/50534.

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The Daya Bay reactor neutrino experiment is a high sensitivity experiment designed to determine the last unknown neutrino mixing angle $theta_{13}$ by measuring disappearance of reactor antineutrinos emitted from six 2.9 $GW_{th}$ reactors at the Daya Bay Nuclear Power Station. There are eight identical Gd-loaded liquid scintillator detectors deployed in two near (flux-weighted baseline 512 $m$ and 561 $m$) and one far (1579 $m$) underground experimental halls to detect the inverse beta decay interaction. This dissertation describes the Daya Bay Experiment and individual contributions to this

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Currens, Benjamin J. "DEUTERIUM AND OXYGEN-18 DIFFUSION IN A CONFINED AQUIFER: A NUMERICAL MODEL OF STABLE ISOTOPE DIFFUSION ACROSS AQUITARD-AQUIFER BOUNDARIES." UKnowledge, 2016. http://uknowledge.uky.edu/ees_etds/40.

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The stable isotopes 2H and 18O, combined with noble gases and radioisotopes (e.g., 3H, 14C, 36Cl), are used to infer groundwater age and climate during recharge. Flow regimes within low-velocity flowpaths and long residence times could allow an aquitard-aquifer diffusive flux to alter isotope abundance. Consequently, the diffusion of isotopes (e.g., 14C, 2H and 18O) between aquifers and confining layers needs to be considered in such conditions. In this study, COMSOL Multiphysics was used to determine if diffusion of 18O (and 2H by proxy) from a bounding aquitard could explain observed downgra

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Roston, Daniel Harris. "The use of kinetic isotope effects in studies of hydrogen transfers." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/1498.

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The present dissertation seeks to deepen our understanding of hydrogen transfers and especially C-H bond activations in enzymes. Hydrogen transfers are ubiquitous in chemistry and biology and a thorough understanding of how they occur and what factors influence them will facilitate developments in biomimetic catalysis, rational drug design, and other fields. A particular difficulty with H-transfers is the importance of nuclear quantum effects to the reaction, particularly tunneling. The overall scope of the work here aims to examine how experimental kinetic isotope effects (KIEs) can be interp

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Gottardo, Andrea. "Isomer decay spectroscopy in the region of neutron-rich lead isotopes from relativistic 238U fragmentation." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3425455.

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The present thesis describes the results of an experiment which was performed at the GSI laboratory, Darmstadt, Germany in September 2009, aiming at studying neutron-rich nuclei in the region of lead nuclei. In the introduction the main modern research lines on nuclear structure are briefly described. A particular attention is devoted to the study of exotic nuclei, i.e. of nuclei far from the valley of stability. They are one of the most important themes of research in nuclear physics since their study may point out details of the nuclear interaction not easy to disentangle investigating only

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Zeng, Lingsen Taylor Hugh P. "Non-modal partial melting of metasedimentary pendants in the southern Sierra Nevada and implications for the deep origin of within-pluton isotopic heterogeneity /." Diss., Pasadena, Calif. : California Institute of Technology, 2004. http://resolver.caltech.edu/CaltechETD:etd-10272003-131444.

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Athanason, Mark Gabriel. "Quantitative Proteomic Investigation of Disease Models of Type 2 Diabetes." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6460.

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PANcreatic DERived factor (PANDER, FAM3B) is a member of a superfamily of FAM3 proteins that are uniquely structured and strongly expressed from the endocrine pancreas and co-secreted with insulin. Unique animal models available to our lab have indicated that PANDER can induce a selective hepatic insulin resistant (SHIR) phenotype whereby insulin signaling is blunted yet lipogenesis is increased. The complexity of the biological networks involved with this process warranted the logical approach of employing quantitative mass spectrometry based proteomic analysis using stable isotope labeling o

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Ma, Zhegang. "Development of MURR flux trap model for simulation and prediction of sample loading reactivity worth and isotope production." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://edt.missouri.edu/Winter2007/Dissertation/MaZ-050807-D7038/.

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Thesis (Ph. D.)--University of Missouri-Columbia, 2007.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 27, 2007) Vita. Includes bibliographical references.

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Moiroud, Mathieu. "Evolution de la circulation oécanique profonde durant le Crétacé : apport des isotopes du néodyme." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS030/document.

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Le Crétacé est décrit comme la période la plus chaude des derniers 300 millions d’années. La circulation océanique et l’origine des eaux profondes alimentant les bassins restent mal connues pour le Crétacé, alors qu’elles sont capitales dans la compréhension du rôle de l’océan dans l’évolution du climat à cette époque. Les isotopes du néodyme (Nd) permettent de tracer la circulation océanique et les échanges entre les masses d’eau, et ont été utilisés pour explorer la circulation océanique globale des océans actuels et dans le passé. La composition isotopique en Nd (εNd) des océans dérive de c

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Pierce, Natashia M. "Geochemical and isotopic discrimination of meta-volcanics from the Rowe-Hawley Zone of western New England: A discussion of along-strike translation of tectonic models." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378112536.

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Truebe, Sarah, and Sarah Truebe. "Past Climate, Modern Caves, and Future Resource Management in Speleothem Paleoclimatology." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621105.

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My research focuses on reconstructing past climate in southern Arizona using cave deposits called speleothems. However, this necessitates a broader perspective than simply a geochemical time series, and therefore, I also investigate modern cave systems using a combination of modeling and observational datasets. Finally, cave deposits are fundamentally non-renewable resources, and sampling for past climate reconstruction can be destructive, unlike other cave uses. My last investigation is focused on developing possible best practice recommendations for paleoclimate scientists and other cave sta

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Cooling, Christopher. "Development of a point kinetics model with thermal hydraulic feedback of an aqueous homogeneous reactor for medical isotope production." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24969.

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This thesis presents the development of a model of the Medical Isotope Production Reactor (MIPR): a conceptual Aqueous Homogeneous Reactor (AHR). The model is a point kinetics model with zero and one-dimensional thermal hydraulic feedbacks. Three versions of the model of increasing complexity are presented and a number of scenarios are modelled with each version. The results of these simulations shows the stability of the reactor against reactivity insertions caused by the strong negative reactivity feedbacks inherent to AHRs. The first version of the model is modified using intrusive polynomi

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