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Academic literature on the topic 'Stable isotope tracer'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 February 2022

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Journal articles on the topic "Stable isotope tracer"

1

Cobelli, C., G. Toffolo, D. M. Bier, and R. Nosadini. "Models to interpret kinetic data in stable isotope tracer studies." American Journal of Physiology-Endocrinology and Metabolism 253, no. 5 (November 1, 1987): E551—E564. http://dx.doi.org/10.1152/ajpendo.1987.253.5.e551.

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In contrast to "weightless" radioactive tracers, stable isotope tracers have nonnegligible mass and are naturally present in the system, and the measured variable is a ratio of two isotopic species. These features do not allow stable isotopic tracer data analysis using straightforward analogy with radioactive tracer approaches, even though this practice is common. In this study, we present kinetic variables, models, and measurements for the analysis and interpretation of stable isotope tracer data. Assumptions and mathematical techniques for modeling the data when perturbation is both nonnegligible and negligible are discussed. Emphasis is placed on the rich information content of the dynamic portion of a stable isotope tracer curve and on the role of compartmental and noncompartmental modeling approaches for its interpretation. A presumed and commonly used analogy between the radioactive specific activity and stable isotopic enrichment is shown to be incorrect. We show that the proper analogue of specific activity is the tracer-to-tracee molar ratio. This variable is not a directly measurable one, but a formula is derived that allows its computation from the data. A method for reconstructing the time course in blood of the concentration component due to endogenous synthesis is presented. This allows measurement of the extent of the perturbation in the case where a nonweightless tracer is used. Special attention is given to data analysis originating from a multiple tracer experiment, a configuration necessary for studying more complex systems, e.g., the kinetics of interacting substrates.

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Rosenblatt, J., and R. R. Wolfe. "Calculation of substrate flux using stable isotopes." American Journal of Physiology-Endocrinology and Metabolism 254, no. 4 (April 1, 1988): E526—E531. http://dx.doi.org/10.1152/ajpendo.1988.254.4.e526.

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The use of stable isotope tracers to calculate substrate kinetics in humans is favored over the use of radioactive isotopes because of their greater safety and versatility. However, potential complications not met when dealing with radioactive tracers are caused by 1) the natural occurrence of the stable isotope used as a tracer and 2) the necessity to administer the tracer in an amount that cannot be treated as "massless." We therefore found it desirable to derive a theoretically valid equation for calculating the rate of appearance, Ra, of a substrate under steady-state conditions using a stable isotope tracer. This theoretically valid equation yields results that differ from those of the equations conventionally used to calculate (endogenous) Ra in steady state. Quantitative determination of the error in one of these equations revealed that for tracers commonly used in metabolic studies the error is negligible, whereas the error made in the other equation is likely to be quite high in commonly encountered situations. Finally, to allow for proper use of different definitions of isotopic enrichment that have arisen from practical considerations, we use the results derived above to determine valid equations for Ra appropriate to the two prevalent definitions.

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Patterson, Kristine Y., and Claude Veillon. "Stable Isotopes of Minerals as Metabolic Tracers in Human Nutrition Research." Experimental Biology and Medicine 226, no. 4 (April 2001): 271–82. http://dx.doi.org/10.1177/153537020122600403.

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Enriched stable isotopes used as tracers have proven to be valuable in studies of the absorption and metabolism of minerals. Unlike radioisotopes, they can be used in high-risk population groups such as infants, children, and pregnant or lactating women. Estimates of mineral absorption can be made from the oral administration of a single tracer or from two tracers, one given orally and the other intravenously (IV). It is possible to determine the metabolism of the mineral with modeling based on the amount of the tracer or tracers in different biological samples. One of the key decisions in studies of this type is determining which enriched isotope and what amount to use. An example is given of calculations to estimate and compare the amounts of tracers needed for an absorption study. Methods for calculating the amounts of tracer in oral and IV doses are presented, and limits of detection and quantitation are discussed in terms of percent of enrichment and related to isotope ratio measurement precision. A general review of the use of mass spectrometric instruments for quantifying various stable isotopes is given.

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Argoud, G. M., D. S. Schade, and R. P. Eaton. "Underestimation of hepatic glucose production by radioactive and stable tracers." American Journal of Physiology-Endocrinology and Metabolism 252, no. 5 (May 1, 1987): E606—E615. http://dx.doi.org/10.1152/ajpendo.1987.252.5.e606.

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Although negative hepatic glucose production rates are physiologically impossible, they have been observed when hepatic glucose production is measured with the tracer-dilution technique during the hyperinsulinemic, euglycemic glucose clamp. Because hepatic glucose production is determined from the difference between tracer-derived glucose disposal and the known exogenous glucose infusion rate, the negative values for hepatic glucose production must result from an underestimation of glucose disposal by the tracer technique. In the current investigation, tracer-derived glucose disposal was measured in 25 subjects undergoing hyperinsulinemic, euglycemic clamps. Glucose disposal was measured with both radioactive and stable isotopes that utilize different methodologies, to determine whether discriminant metabolism of the isotopes versus methodological error leads to underestimation of tracer-derived glucose disposal. Both the radioactive and stable methodologies underestimated the exogenous glucose infusion rate during the hyperinsulinemic euglycemic clamp by 27 and 17%, respectively. Mean hepatic glucose production was -2.1 +/- 0.2 and -1.3 +/- 0.2 mg X kg-1 X min-1 as determined by the radioactive and stable isotope methodologies, respectively. Methodological error was an unlikely cause of this underestimation because it occurred with two different methodologies. The most likely explanation for underestimated rates of glucose disposal determined by the two types of isotope methodologies is discrepant metabolism of glucose tracers in comparison with unlabeled glucose.

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Jeong, Heesoo, Yan Yu, Henrik J. Johansson, Frank C. Schroeder, Janne Lehtiö, and Nathaniel M. Vacanti. "Correcting for Naturally Occurring Mass Isotopologue Abundances in Stable-Isotope Tracing Experiments with PolyMID." Metabolites 11, no. 5 (May 12, 2021): 310. http://dx.doi.org/10.3390/metabo11050310.

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Stable-isotope tracing is a method to measure intracellular metabolic pathway utilization by feeding a cellular system a stable-isotope-labeled tracer nutrient. The power of the method to resolve differential pathway utilization is derived from the enrichment of metabolites in heavy isotopes that are synthesized from the tracer nutrient. However, the readout is complicated by the presence of naturally occurring heavy isotopes that are not derived from the tracer nutrient. Herein we present an algorithm, and a tool that applies it (PolyMID-Correct, part of the PolyMID software package), to computationally remove the influence of naturally occurring heavy isotopes. The algorithm is applicable to stable-isotope tracing data collected on low- and high- mass resolution mass spectrometers. PolyMID-Correct is open source and available under an MIT license.

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Preston, Tom. "Existing and Emerging Technologies for Measuring Stable Isotope Labelled Retinol in Biological Samples: Isotope Dilution Analysis of Body Retinol Stores." International Journal for Vitamin and Nutrition Research 84, Supplement 1 (December 1, 2014): 30–39. http://dx.doi.org/10.1024/0300-9831/a000186.

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This paper discusses some of the recent improvements in instrumentation used for stable isotope tracer measurements in the context of measuring retinol stores, in vivo. Tracer costs, together with concerns that larger tracer doses may perturb the parameter under study, demand that ever more sensitive mass spectrometric techniques are developed. GCMS is the most widely used technique. It has high sensitivity in terms of sample amount and uses high resolution GC, yet its ability to detect low isotope ratios is limited by background noise. LCMSMS may become more accessible for tracer studies. Its ability to measure low level stable isotope tracers may prove superior to GCMS, but it is isotope ratio MS (IRMS) that has been designed specifically for low level stable isotope analysis through accurate analysis of tracer:tracee ratios (the tracee being the unlabelled species). Compound-specific isotope analysis, where GC is interfaced to IRMS, is gaining popularity. Here, individual 13C-labelled compounds are separated by GC, combusted to CO2 and transferred on-line for ratiometric analysis by IRMS at the ppm level. However, commercially-available 13C-labelled retinol tracers are 2 - 4 times more expensive than deuterated tracers. For 2H-labelled compounds, GC-pyrolysis-IRMS has now become more generally available as an operating mode on the same IRMS instrument. Here, individual compounds are separated by GC and pyrolysed to H2 at high temperature for analysis by IRMS. It is predicted that GC-pyrolysis-IRMS will facilitate low level tracer procedures to measure body retinol stores, as has been accomplished in the case of fatty acids and amino acids. Sample size requirements for GC-P-IRMS may exceed those of GCMS, but this paper discusses sample preparation procedures and predicts improvements, particularly in the efficiency of sample introduction.

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Cobelli, C., G. Toffolo, and D. M. Foster. "Tracer-to-tracee ratio for analysis of stable isotope tracer data: link with radioactive kinetic formalism." American Journal of Physiology-Endocrinology and Metabolism 262, no. 6 (June 1, 1992): E968—E975. http://dx.doi.org/10.1152/ajpendo.1992.262.6.e968.

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A kinetic formalism for the analysis of stable isotope transient tracer data is developed by establishing the link with the formalism available for radioactive tracer data. The crucial variable is the tracer-to-tracee ratio. By expressing the measurements in terms of this ratio, the conventional kinetic formalism used for radioactive data can be applied to estimate noncompartmental parameters using stable isotope tracer data. The tracer-to-tracee ratio also plays an important role in compartmental modeling. By considering the tracer masses in the compartments as state variables the system-experiment model can be written in a format analogous to that usually adopted for the radioactive tracer. Finally, it is shown that the tracer-to-tracee ratio also plays a role in a test of the endogenous steady-state assumption.

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Jahn, A., K. Lindsay, X. Giraud, N. Gruber, B. L. Otto-Bliesner, Z. Liu, and E. C. Brady. "Carbon isotopes in the ocean model of the Community Earth System Model (CESM1)." Geoscientific Model Development 8, no. 8 (August 5, 2015): 2419–34. http://dx.doi.org/10.5194/gmd-8-2419-2015.

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Abstract. Carbon isotopes in the ocean are frequently used as paleoclimate proxies and as present-day geochemical ocean tracers. In order to allow a more direct comparison of climate model results with this large and currently underutilized data set, we added a carbon isotope module to the ocean model of the Community Earth System Model (CESM), containing the cycling of the stable isotope 13C and the radioactive isotope 14C. We implemented the 14C tracer in two ways: in the "abiotic" case, the 14C tracer is only subject to air–sea gas exchange, physical transport, and radioactive decay, while in the "biotic" version, the 14C additionally follows the 13C tracer through all biogeochemical and ecological processes. Thus, the abiotic 14C tracer can be run without the ecosystem module, requiring significantly fewer computational resources. The carbon isotope module calculates the carbon isotopic fractionation during gas exchange, photosynthesis, and calcium carbonate formation, while any subsequent biological process such as remineralization as well as any external inputs are assumed to occur without fractionation. Given the uncertainty associated with the biological fractionation during photosynthesis, we implemented and tested three parameterizations of different complexity. Compared to present-day observations, the model is able to simulate the oceanic 14C bomb uptake and the 13C Suess effect reasonably well compared to observations and other model studies. At the same time, the carbon isotopes reveal biases in the physical model, for example, too sluggish ventilation of the deep Pacific Ocean.

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Jahn, A., K. Lindsay, X. Giraud, N. Gruber, B. L. Otto-Bliesner, Z. Liu, and E. C. Brady. "Carbon isotopes in the ocean model of the Community Earth System Model (CESM1)." Geoscientific Model Development Discussions 7, no. 6 (November 6, 2014): 7461–503. http://dx.doi.org/10.5194/gmdd-7-7461-2014.

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Abstract. Carbon isotopes in the ocean are frequently used as paleo climate proxies and as present-day geochemical ocean tracers. In order to allow a more direct comparison of climate model results with this large and currently underutilized dataset, we added a carbon isotope module to the ocean model of the Community Earth System Model (CESM), containing the cycling of the stable isotope 13C and the radioactive isotope 14C. We implemented the 14C tracer in two ways: in the "abiotic" case, the 14C tracer is only subject to air–sea gas exchange, physical transport, and radioactive decay, while in the "biotic" version, the 14C additionally follows the 13C tracer through all biogeochemical and ecological processes. Thus, the abiotic 14C tracer can be run without the ecosystem module, requiring significantly less computational resources. The carbon isotope module calculates the carbon isotopic fractionation during gas exchange, photosynthesis, and calcium carbonate formation, while any subsequent biological process such as remineralization as well as any external inputs are assumed to occur without fractionation. Given the uncertainty associated with the biological fractionation during photosynthesis, we implemented and tested three parameterizations of different complexity. Compared to present-day observations, the model is able to simulate the oceanic 14C bomb uptake and the 13C Suess effect reasonably well compared to observations and other model studies. At the same time, the carbon isotopes reveal biases in the physical model, for example a too sluggish ventilation of the deep Pacific Ocean.

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Hungate, Bruce A., Rebecca L. Mau, Egbert Schwartz, J. Gregory Caporaso, Paul Dijkstra, Natasja van Gestel, Benjamin J. Koch, et al. "Quantitative Microbial Ecology through Stable Isotope Probing." Applied and Environmental Microbiology 81, no. 21 (August 21, 2015): 7570–81. http://dx.doi.org/10.1128/aem.02280-15.

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ABSTRACTBacteria grow and transform elements at different rates, and as yet, quantifying this variation in the environment is difficult. Determining isotope enrichment with fine taxonomic resolution after exposure to isotope tracers could help, but there are few suitable techniques. We propose a modification tostableisotopeprobing (SIP) that enables the isotopic composition of DNA from individual bacterial taxa after exposure to isotope tracers to be determined. In our modification, after isopycnic centrifugation, DNA is collected in multiple density fractions, and each fraction is sequenced separately. Taxon-specific density curves are produced for labeled and nonlabeled treatments, from which the shift in density for each individual taxon in response to isotope labeling is calculated. Expressing each taxon's density shift relative to that taxon's density measured without isotope enrichment accounts for the influence of nucleic acid composition on density and isolates the influence of isotope tracer assimilation. The shift in density translates quantitatively to isotopic enrichment. Because this revision to SIP allows quantitative measurements of isotope enrichment, we propose to call it quantitative stable isotope probing (qSIP). We demonstrated qSIP using soil incubations, in which soil bacteria exhibited strong taxonomic variations in18O and13C composition after exposure to [18O]water or [13C]glucose. The addition of glucose increased the assimilation of18O into DNA from [18O]water. However, the increase in18O assimilation was greater than expected based on utilization of glucose-derived carbon alone, because the addition of glucose indirectly stimulated bacteria to utilize other substrates for growth. This example illustrates the benefit of a quantitative approach to stable isotope probing.

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Dissertations / Theses on the topic "Stable isotope tracer"

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Sutton, David G. M. "Stable isotope tracer studies for the measurement of equine gastrointestinal motility." Thesis, University of Glasgow, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422249.

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Aravindhan, Karpagam Jucker Beat M. DiNardo N. John. "Assessing the effects of LXR agonists in cholesterol handling: stable isotope tracer studies /." Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/613.

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Pérez, Moreno Rodrigo. "Stable isotope and anthropogenic tracer signature of waters in an andean geothermal system." Tesis, Universidad de Chile, 2019. http://repositorio.uchile.cl/handle/2250/170853.

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Tesis para optar al grado de Magíster en Ciencias, Mención Geología
El presente trabajo se centra en el uso de isótopos estables y trazadores antropogénicos para investigar el origen, los tiempos de residencia y la evolución de las aguas termales en el Complejo Volcánico Lonquimay-Tolhuaca, ubicado en la parte central de la Zona Volcánica Sur. Veinte muestras de agua subterránea, surgiendo en un amplio rango de temperaturas (8-96°C), son analizadas para determinar su composición química, incluyendo elementos mayores, razones isotópicas (δ2H, δ18O, δ13CTDIC) y la concentración de clorofluorocarbonos (CFCs) y hexafluoruro de azufre (SF6) disueltos. Adicionalmente, se presenta un compilado de toda la información disponible sobre la composición isotópica de la precipitación en la región de la Araucanía. Mediante un modelo de fraccionamiento de Rayleigh aplicado a los isótopos de oxígeno, se logra constreñir la elevación a la cual se produce la recarga del sistema. Los valores de δ13CTDIC en las aguas indican la adición de CO2 del suelo a una fuente de origen atmosférico en la mayoría de las muestras. No obstante, procesos de ebullición y desgasificación magmática se evidencian en las surgencias termales ubicadas en los flancos de volcanes. La composición isotópica de las aguas termales, una vez calentadas en profundidad, es modificada posteriormente por procesos de desgasificación de CO2 y precipitación de carbonatos durante su ascenso. Todas las muestras de aguas termales presentan concentraciones bajas pero detectables de CFC-11, CFC-12, CFC-113 y SF6, lo que sugiere la adición de una pequeña fracción (2 a 22%) de agua meteórica moderna al sistema. La temperatura de surgencia de las aguas termales en el Complejo Volcánico Lonquimay-Tolhuaca se relaciona directamente con la distribución de edad en las muestras. Estas diferencias en los tiempos de residencia se atribuyen a los distintos mecanismos de circulación de cada tipo de agua: por un lado, las aguas frías poseen tiempos de residencia cortos y evidencian una circulación somera a través de un medio poroso, mientras que las aguas termales poseen tiempos de residencia mayores y evidencian un flujo canalizado a través de zonas de falla. El flujo de las aguas termales a través de estos conductos de alta permeabilidad vertical impide que sean diluidas con agua meteórica durante el ascenso. Los datos de este estudio confirman que las redes de fallas y fracturas con distintas orientaciones ejercen un control sobre los tiempos de residencia, el ascenso y las tasas de mezcla de distintos fluidos en este segmento de la Cordillera de los Andes, determinando así su composición química e isotópica. Asimismo, nuestros resultados muestran que el análisis geoquímico e isotópico convencional, en conjunto con el uso de trazadores ambientales (incluyendo los trazadores antropogénicos, CFC y SF6) son una poderosa herramienta para entender la dinámica hídrica de los sistemas geotermales.
Centro de Excelencia en Geotermia de los Andes (CEGA), proyecto FONDAP-CONICYT 15090013, y por el Núcleo Milenio Trazadores de Metales NC130065

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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 a small suite of geographic and climate variables generate the best performing long-term and seasonal models of δ18Oppt. These models are used to develop long term isoscapes for Canada, which capture the general spatial and seasonal trends in δ18Oppt, showing an improvement upon results from previous studies using global models. Building upon long-term δ18Oppt prediction, δ18Oppt observations alongside climatological and geographic predictors are used to create empirical time series prediction models. Five regionalization approaches are used to separate the study domain into isotope zones to explore the effect of spatial grouping on simulations. Generally, the models capture the timing and magnitude of intra-annual (seasonal) δ18Oppt cycles across the study domain while simulating moderate inter-annual variation; however often fail to capture the anomalies in observed δ18Oppt. Uncertainty in predictions is quantified spatially and temporally, and the Köppen-Geiger (Kpn) regionalization is selected as the preferred regionalization scheme for future applications due to adequate model performance and lack of border issues at regional boundaries. Finally, estimates of monthly δ18Oppt from Kpn models, long term annual averages, and daily REMOiso output are used to force an isotope-enabled hydrological model, isoWATFLOOD, in the Fort Simpson Basin, NWT, Canada. Results show streamflow simulations are not significantly impacted by choice of δ18Oppt input; however, oxygen-18 in streamflow and the internal apportionment of water (and model parameterizations) are impacted, particularly during large precipitation and snowmelt events. This work shows how isoWATFLOOD can be used in regions with limited δ18Oppt observations, and that the model can be of value in such regions. This study reinforces that a tracer-aided modelling approach works towards diagnosing issues surrounding model equifinality.
February 2017

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Koenig, Karen Marie. "True absorption of selenium in dairy cows : stable isotope tracer methodology and effect of dietary copper." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27972.

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Gas chromatography mass spectrometry (GCMS) and inductively coupled plasma mass spectrometry (ICPMS) were evaluated for the measurement of selenium (Se) and Se stable isotope ratios. GCMS and ICPMS were found to be accurate for quantitative Se analysis in biological matrices by isotope dilution using Se-78 and Se-76 as internal standards, respectively. A higher precision was obtained for ICPMS than GCMS enabling a smaller quantity of the tracer to be administered to subjects in labelling experiments. The isotopes of choice for metabolic tracers were Se-76 when sample analysis was by GCMS and Se-77 and Se-82 when analysis was by ICPMS. The influence of copper (Cu) on endogenous fecal Se excretion and true absorption of Se in nonlactating Holstein cows was examined by the use of Se stable isotopes as tracers. The method involved the application of conventional balance techniques in conjunction with isotopic enrichment of the body Se pools. Selenium in several tissues following oral and intravenous routes of isotope administration were evaluated as the precursors of endogenous fecal Se. Two cows fed a Se deficient diet (0.035 mg kg⁻¹) were administered 4 mg Se-76 orally, daily, for 5 d. After a 10-d equilibration period total collection of feces was made daily for two 5-d periods. The animals were then sacrificed and samples obtained from all major tissues and fluids. Se-7 6 enrichment (tracer/tracee mass percent, TTMP) in tissues was variable (< 0.56 - 13.4). However, enrichment was similar (9.8 - 12.9) in the tissues considered as potential contributors to endogenous fecal Se (serum, epithelium of the stomach, liver, bile, pancreas, small intestine and colon). Enrichment in serum and liver was used to calculate endogenous fecal Se. Apparent absorption of Se in the two cows was negative (-37 and -147 µg d⁻¹). Correction of apparent absorption for the fecal Se of endogenous origin gave a true Se absorption (% of intake) of 10 and 16%. The percentage of total fecal Se of endogenous origin was 23 and 36%. In two trials, 5 or 6 cows were assigned to one of two Cu-supplemented treatment diets: 0 mg kg⁻¹ or 17 mg kg⁻¹. The basal diet contained 0.19 mg Se kg⁻¹ and 13 mg Cu kg⁻¹. To each cow ~4.6 mg Se-77 and ~1.3 mg Se-82 were administered by oral and intravenous routes, respectively. After a 14-d equilibration period, total collection of feces and urine were made daily for two 5-d periods. Serum was collected on the first, third and fifth days of each period. Liver biopsies were taken 2 d following the completion of the balance periods. The estimates of endogenous fecal Se ( d⁻¹) from enrichment in the serum (256) and liver (235) following oral administration of the tracer and from enrichment in serum (241) following intravenous administration were not significantly different (P>0.05) but were higher than the estimate from the enrichment in liver (197) (P<0.05). No significant differences (P>0.05) were present when true absorption ( µg d⁻¹) was determined from enrichment in serum (290) or liver (268) following oral administration or from enrichment in serum (274) or liver (230) following intravenous administration. It was concluded the analysis of serum or liver with oral administration or the analysis of serum with intravenous administration of the tracer would provide reliable methods for estimation of endogenous fecal Se and true absorption. There was no effect of Cu on endogenous fecal Se excretion or true absorption of Se. Apparent and true absorption were 3.2 and 11%, respectively. Approximately 90% of the total Se excreted was in the feces, of which, 9.7% was of endogenous origin. The use of Se stable isotopes as metabolic tracers in dairy cattle provided a safe alternative to the use of radioactive tracers and enabled experiments requiring multi-isotopic enrichment to be performed.
Land and Food Systems, Faculty of
Graduate

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Mangwende, Tapera Elias. "Quantifying nitrogen leaching in wheat (Triticum aestivum L.) using lysimeter stable isotope conservative tracer and modelling techniques." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65909.

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Nitrogen (N) leaching is one of the important pathways that leads to water pollution, and previous studies have highlighted the difficulty in measuring it. The purpose of this study was to evaluate different techniques used to quantify nitrate-N (NO3-N) leaching load and determine fertiliser N use efficiency (FNUE). Lysimeter and field trial sites were planted with wheat (Triticum aestivum) (PAN3400 cultivar) at the University of Pretoria Experimental Farm, Hatfield, Pretoria. Two weighing lysimeters and a drain gauge were installed at the lysimeter trial site. Water content sensors and suction cups (SCs) were installed at 0.15, 0.3, 0.5 and 0.7 m depths in the weighing lysimeters and close to the drain gauge, while SCs, wetting front detectors (WFDs) and water content sensors were installed at 0.25 and 0.5 m in the field trial site. The crop was fertilised with 200 kg N ha-1 at both sites, but no fertiliser was applied on unfertilised control plots at the field trial site. High density drip irrigation was used at both sites, and bromide (Br-) was applied to all field plots at 0.020 kg m-2. Water was sampled from the SCs, WFDs and the bottom of weighing lysimeters and drain gauge to determine soil water NO3-N and Br- concentrations. Soil samples collected before and after the trial, and plant samples taken at tillering, flowering and physiological maturity were analysed for plant N% and stable 15N natural abundance using a mass spectrometer. Phenological and growth data from the lysimeter trial were used to calibrate Agricultural Production Systems sIMulator (APSIM) model for the first time (according to our knowledge) on wheat in South Africa. The model was then validated using data from the field trial. The drain gauge drained more frequently and in greater amounts than the weighing lysimeters, and NO3- was observed in drainage water from the drain gauge, but was undetectable from the weighing lysimeters drainage possibly because of saturated bottom layer that promoted denitrification. Based on stable 15N natural abundance, the FNUE was 68%, so the fertilised crop did not use 32% of the applied fertiliser. Good correlation was noted between the flag leaf and total plant N% at physiological maturity, indicating that flag leaf can be used to determine the FNUE without requiring whole plant analysis. The potential NO3-N leaching determined using a Br- conservative tracer was 51.5 kg ha-1 season-1. In fertilised plots, the calibrated model predicted NO3-N leaching of 22.7 kg ha-1 season-1, which was slightly lower than the drain gauge measured NO3-N leaching 24.9 kg ha-1 season. Therefore, the drain gauge shows excellent promise in quantifying N leaching but will require further testing under a range of cropping systems. Since the measured drain gauge and simulated NO3-N leaching agreed, and variables such as grain yield, total above dry matter, leaf area index and soil water content were reasonably simulated, the APSIM model can be applied to wheat cropping systems to improve N management decisions. The model confirmed that proper timing of N applications can reduce leaching losses, but further tests are required in several wheat growing agro-ecological zones to explore N management options that minimise N leaching losses. Even without measurements and/or modelling of N losses and crop uptake, results of this study for wheat indicate that the 15N stable isotopes can be used on its own to estimate FNUE, but more studies from different soil types and on wheat varieties are required to verify the trends observed in this study.
Dissertation (MSc (Agric))--University of Pretoria, 2017.
Agricultural Economics, Extension and Rural Development
MSc (Agric)
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Hean, Jeffrey William. "The trophic ecology of waterbirds in a small temperate estuary: a stable isotope and lipid tracer approach." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/54356.

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Waterbirds are often overlooked as predators in aquatic ecosystems, despite the fact that waterbirds congregate in great numbers in and around waterways, notably estuaries. To fully appreciate the effect that aquatic feeding waterbird species may have on aquatic prey communities and the role that they play in estuarine food webs, stable isotopes and fatty acid profiles were employed to examine the seasonal diet of selected waterbirds in the Kowie Estuary, Eastern Cape Province, South Africa. Population counts were conducted every month for four seasons to examine the demography of waterbirds in the lower reaches of the estuary. The mean monthly energy consumption, along with dry matter intake of all waterbird species observed, were calculated and compared to similar estuaries in South Africa and elsewhere. Three duck species, one migrant sandpiper and one piscivore were selected for more detailed investigation at several temporal scales. This thesis has revealed that stable isotope analysis of waterbird tissues provides more informative data than fatty acid analysis for investigating waterbird diet and basal resource-tertiary consumer nutrient coupling. Stable δ15N and δ13C isotopes from several body tissues, in conjunction with SIAR models, were used to determine the seasonal diet of each waterbird species, while fatty acid profiles were investigated to examine the trophic transfer of fatty acids from basal resources to waterbird predators via the benthic fauna. Stable isotopes revealed that Cape Shoveller, Cape Teal and Yellow-Billed Duck shifted their diet over both long and short temporal scales, while the migratory Ruff and piscivorous Little Egret maintained a relatively consistent diet over time. Isopods, amphipods, copepods and Mysidacea were the main foods of all three duck species and the Ruff (>30%). Little Egret fed mainly on flathead mullet throughout the year. Fatty acid analysis revealed evidence for trophic transfer of specific fatty acids from basal resources to waterbirds in the Kowie Estuary but provided little information on seasonal diet of waterbirds. Waterbirds foraging in the Kowie Estuary appeared to shift their diet to coincide with resource abundance pulses, but also displayed seasonal dietary overlap. This study highlights the role that waterbirds play in aquatic food webs. The subject requires more attention so that we can better understand all the predatory drivers on aquatic communities.

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Sumrall, Jonathan. "Using 34-S as a tracer of dissolved sulfur species from springs to cave sulfate deposits in the Cerna Valley, Romania." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002833.

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Hajj, Fadi. "Utilisation des isotopes stables et radiogéniques du strontium pour tracer la provenance des bois : application à des épaves sous-marines." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0334.

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Au début des temps modernes (16ème - 18ème siècles), la construction de grands navires était primordiale pour le développement des rencontres culturelles dans ce qui est devenu l'âge de la découverte et de l'expansion européenne. L’Espagne était une des grandes puissances de l’époque. Le projet européen « ForSEAdiscovery » cherche dans ce contexte à répondre aux questions clés suivantes : les ressources forestières ibériques de l’époque soutenaient-elles la demande croissante de bois, ou bien ce bois était-il importé d’autres pays ? Si ces bois ne provenaient pas de l’Espagne, comment les réseaux de commerce étaient-ils organisés ? Ce projet aborde ces questions à travers un programme de recherche multidisciplinaire et innovant pour améliorer la compréhension de notre passé historique et de notre patrimoine culturel, et développer notre connaissance sur l'utilisation passée des ressources en bois pour la construction navale. L'objectif de cette thèse, qui s’insère dans ce projet, est d’identifier la provenance des bois utilisés dans la construction navale ibérique en utilisant des traceurs géochimiques. L’hypothèse est que les arbres se développant sur des roches et des sols contrastés possèdent des signatures géochimiques spécifiques héritées des roches. Les signatures isotopiques en strontium (87Sr/86Sr) peuvent notamment être des indicateurs de provenance géographique. Dans ce contexte, la démarche suivie dans la thèse a consisté à caractériser la signature isotopique en Sr dans des bois d'épaves de bateaux et dans les bois d’arbres actuels, les sols et roches prélevés dans les principaux peuplements forestiers espagnols pointés comme lieux de production des bois entre le 16ème - 18ème siècles. Les signatures en δ88/86Sr, traceur peu connu encore, ont également été caractérisées dans les échantillons. Les types et les âges des roches ont été caractérisés et les liens entre les rapports isotopiques 87Sr/86Sr et δ88/86Sr dans les roches, sols et arbres ont été étudiés sur les sites espagnols échantillonnés. La signature locale des sites espagnols potentiels de provenance de bois a été déterminée. Nos résultats mettent en évidence que le rapport isotopique 87Sr/86Sr dans les arbres reflète la signature de la fraction échangeable des sols sur lesquels ils croissent alors que le δ88/86Sr est affecté par le fractionnement, les isotopes légers (86Sr) étant préférentiellement incorporés dans les arbres laissant la fraction échangeable du sol enrichie avec les isotopes lourds (88Sr). Ce fractionnement observé pour les chênes, n’est pas marqué dans le bois des pins suggérant que le fractionnement isotopique durant le transfert du Sr entre le sol et l’arbre est dépendant de l’espèce. La contamination des bois d’épaves par les éléments marins a été identifiée. Le Sr marin se retrouve notamment sous forme adsorbée ou dans la structure des minéraux précipités dans les bois immergés. Différentes expériences d’extractions ont été testées et un protocole adapté a été développé pour extraire les éléments marins et retrouver la signature originelle du bois archéologique. Nous avons réussi à valider un protocole d’extraction et retrouver la signature originelle d’un échantillon de bois d’épave. Ce résultat souligne le potentiel et l’importance d’une nouvelle méthode combinant 87Sr/86Sr et δ88/86Sr pour des futures études de provenance de bois ou autres matériaux. Cependant, nos résultats indiquent également que beaucoup de nos échantillons de bois archéologiques n’ont pas conservé leur Sr originel. Partant de ce constat, des préconisations sont proposées pour améliorer la possibilité d’utilisation de ce traceur dans les études futures de provenance de bois archéologiques sous-marins
In the Early Modern Age (16th - 18th centuries), the construction of ocean-going ships was paramount to the development of cultural encounters in what became the Age of Discovery and European expansion. Spain was one of the biggest forces of that time. The European project “ForSEAdiscovery” seeks answers in this context to the following key questions: Could Spanish forest resources sustain the increasing demand of timber, or were the wood imported from elsewhere? If Spanish forests were not the only wood supplier, how were the trade networks organized? This project will address these questions through a multidisciplinary and innovative training research program to improve the understanding of our historical past, our cultural heritage, and our knowledge of the use of resources for shipbuilding. The objective of this PhD thesis, taking part of this project, is to identify the provenance of the Iberian shipbuilding wood using geochemical tracers. The hypothesis is that trees growing on contrasted rocks and soils have specific geochemical signatures, which can be an indicator of geographic provenance. In this context, the Sr isotopic signature (87Sr/86Sr) was characterized in shipwreck wood samples and wood from living trees, soils and rocks collected from the Spanish forest stands indicated as potential source of wood between the 16th - 18th centuries. The δ88/86Sr signatures were also characterized in the samples. The rock types and ages were characterized at the selected sites and the link between the 87Sr/86Sr and δ88/86Sr in rocks, soils and trees was studied on the sampled Spanish sites. The local signature of Spanish potential sites was determined for provenance of wood. Our results indicate that 87Sr/86Sr isotope ratios in trees reflect the signature of the corresponding soil exchangeable pool while δ88/86Sr was shown to be affected by mass-dependent fractionation with trees taking up lighter (86Sr) isotopes, leaving the soil exchangeable pool enriched with the heavier isotopes (88Sr). This fractionation observed for oak trees, was not found in pines suggesting that the isotopic fractionation during tree uptake is species dependent. The contamination of wood from shipwrecks by seawater elements was identified. Marine Sr was found to be adsorbed on the wood or included in the precipitated minerals in the waterlogged wood. Several extraction experiments were tested and an adapted protocol was developed to extract the seawater elements and retrieve the original signature of the archaeological wood. We succeeded to validate an extraction protocol and retrieve the original signature of one wood sample. This result underline the potential and importance of a new method combining 87Sr/86Sr and δ88/86Sr values for future provenance studies on wood or other materials. However, our results also indicated that most of our shipwreck wood samples did not conserve their original Sr. Therefore, preconizations were suggested in order to extend the use of this tracer in future provenance studies on archaeological wood from shipwrecks

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Ferreira, Araujo Daniel. "Investigations into isotope biogeochemistry of Zn in coastal areas and mangroves." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30368/document.

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Les zones côtières du monde entier sont sous fort pression de contamination anthropique comme conséquence de la concentration de la plupart de la population mondiale et des activités économiques le long des côtes et des estuaires. La menace de contaminant sur les écosystèmes rend primordial le développement d'outils capable de détecter les modifications biogéochimiques en vue d'aider dans la prévention, la gestion, et la prédiction de risques dans les études environnementales. Dans ce but, cette thèse étudie la biogéochimie des isotopes du Zinc (Zn) en vue de développer un outil capable de tracer les sources naturelles et anthropiques, d'identifier les processus biogéochimiques et de permettre à la biosurveillance de la contamination par les métaux dans les zones côtières et les mangroves. A cette fin, les compositions isotopiques du Zn ont été déterminées à plusieurs échantillons naturels prélevés dans la baie de Sepetiba (au sud-est du Brésil), un estuaire lagunaire affecté par une côte industrialisée située près de Rio de Janeiro. Cette baie constitue un laboratoire naturel idéal pour valider le système isotopique du Zn. En effet, cette zone héberge des écosystèmes d'intérêt commercial et écologique -estuaire, mangrove, estran- menacés par la contamination d'une ancienne activité de galvanoplastie, et d'autres sources diffuses. Les échantillons collectés comprennent des carottes de sédiments, des sédiments de la superficie des mangroves, des matériaux particulaires en suspension (SPM), des feuilles provenant d'arbres de mangrove, des tissus de mollusques bivalves (huîtres et moules) et des roches. Minéraux de dépôt de Vazante (Brésil) ont été collecté pour representé matière première utilisée par l'industrie de la galvanoplastie. Tout d'abord, un travail initial de laboratoire a établi une méthode exacte et précise pour les déterminations isotopiques Zn en échantillons naturelles par spectrométrie de masse avec plasma couplé par induction et multicollecteur (MC-ICP-MS). Des analyses spatiales et temporelles des compositions isotopiques du Zn des échantillons de sédiments et de roches s'ajustent bien à un modèle de mélange entre trois principales extrémités : i) les matériaux continentaux charriés par les rivières ; ii) les sources marines ; et iii) une source anthropique majeure associée aux anciens déchets de galvanoplastie jetés dans la baie. Les carottes de sédiment collectées dans la vasière ont montré une haute corrélation entre la composition isotopique du Zn et le facteur d'enrichissement du Zn. Ceci suggère : i) une bonne préservation du registre isotopique des sources naturelle et anthropique, ii) l'absence de fractionnement isotopique significatif durant le transport de sédiments ou durant les réactions diagénétiques pos-dépositions dans le système estuarien
Coastal areas worldwide are under strong pressure from anthropogenic contamination, as most of the global population and of economic activities are concentrated along the coasts and estuaries. The threaten of contaminant releasing into these ecosystems makes imperative the development of tools capable of detecting biogeochemical changes in order to help prevention, monitoring and prediction of risks in environmental studies. In this way, this thesis investigates the isotope biogeochemistry of Zinc (Zn) in order to develop a tool capable of tracing natural and anthropogenic sources, identifying biogeochemical processes and enabling the biomonitoring of metal contamination in coastal areas and mangroves. To this end, Zn isotopes compositions were determined in several natural samples collected from Sepetiba bay (southeastern Brazil), an estuarine-lagoon impacted by an industrialized coastal area near Rio de Janeiro. This bay constitutes an ideal natural laboratory for evaluating the Zn isotopic system to environmental issues, since it hosts important ecosystems of commercial and ecological interest - estuaries, mangroves and tidal flats - threaten by the metal contamination resultant of old electroplating activity and other anthropogenic diffuse sources. The collected samples include sediment cores, surface mangrove sediments, suspended particulate matter (SPM), leaves of mangrove's trees, tissues of bivalve mollusks (oysters and mussels) and rocks. Ores from Vazante deposit, Brazil were collected to represent the raw material used in the old electroplating industry. Firstly, an initial laboratory work established a method for accurate and precise determinations of Zn isotope compositions in natural samples by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). Spatial and temporal analysis of Zn isotope compositions of sediment and rock samples fits well in a model of mixing between three main end-members: i) continental materials brought via rivers; ii) marine sources; and iii) a major anthropogenic source associated to the old electroplating wastes released into the bay. Sediment cores collected in the mud flat showed high correlation between Zn isotope compositions and Zn enrichment factors, suggesting (i) good preservation of isotopic records of natural and anthropogenic sources and (ii) no significant isotopic fractionation during sediment transport or as a result of diagenetic reactions post-deposition in the estuarine system. The sediment core sampled from a mangrove located in the zone impacted by the old electroplating activity presented levels of Zn up to 4% (dry weight) and preserved the isotopic signatures of electroplating wastes. However, there is evidence that biogeochemical processes triggered by hydrodynamics, bioturbation or rhizosphere processes slightly changed the isotopic signatures in some layers. Calculations based in this mixing model quantified contributions of the major anthropogenic source of Zn, ranging from negligible values in the pre-industrial period to nearly 80% during periods of electroplating activities between the 60's and 90's

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Books on the topic "Stable isotope tracer"

1

Introduction to isotope hydrology: Stable and radioactive isotopes of hydrogen, oxygen and carbon. London: Taylor & Francis, 2006.

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Krumbiegel, Peter. Stable isotope pharmaceuticals: For clinical research and diagnosis. Jena: Gustav Fischer Verlag, 1991.

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service), ScienceDirect (Online, ed. Tracking animal migration with stable isotopes. Amsterdam: Academic Press, 2008.

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Viljoen, G. J., A. G. Luckins, and I. Naletoski. Stable Isotopes to Trace Migratory Birds and to Identify Harmful Diseases. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28298-5.

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Schimel, D. S. Theory and application of tracers. San Diego: Academic Press, 1993.

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R, Wolfe Robert, ed. Radioactive and stable isotope tracers in biomedicine: Principles and practice of kinetic analysis. New York: Wiley-Liss, 1992.

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Schimel, David Steven. Theory and application of tracers. San Diego: Academic Press, 1993.

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Izbicki, John A. Source, movement, and age of ground water in a coastal California aquifer. [Washington, D.C.?]: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Viljoen, G. J. Stable Isotopes to Trace Migratory Birds and to Identify Harmful Diseases: An Introductory Guide. Cham: Springer Nature, 2016.

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Madrid), Jornadas sobre "Nuevas Técnicas Metodológicas Aplicadas al Estudio de los Sistemas Ambientales: los Isótopos Estables" (2005 Universidad Autónoma de. Técnicas y aplicaciones multidisciplinares de los isótopos ambientales. Madrid: Servicio de Publicaciones de la Universidad Autónoma de Madrid, 2008.

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Book chapters on the topic "Stable isotope tracer"

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Skoczen, Sarah L., and Stephan T. Stern. "Improved Ultrafiltration Method to Measure Drug Release from Nanomedicines Utilizing a Stable Isotope Tracer." In Methods in Molecular Biology, 223–39. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7352-1_19.

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Lampert, Winfried, and Jonathan Grey. "Exploitation of a deep-water algal maximum by Daphnia: a stable-isotope tracer study." In Aquatic Biodiversity, 95–101. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-007-1084-9_6.

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Fukushima, Kazuhiko. "Stable Isotope Tracer Experiments Give Strong Evidence Supporting a Controversial Pathway in Lignin Biosynthesis." In Improvement of Forest Resources for Recyclable Forest Products, 163–66. Tokyo: Springer Japan, 2004. http://dx.doi.org/10.1007/978-4-431-53963-6_30.

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Fry, Brian. "Using Stable Isotope Tracers." In Stable Isotope Ecology, 40–75. New York, NY: Springer New York, 2006. http://dx.doi.org/10.1007/0-387-33745-8_3.

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Yoshinari, Tadashi. "Emissions of N2O from Various Environments — The Use of Stable Isotope Composition of N2O as Tracer for the Studies of N2O Biogeochemical Cycling." In Denitrification in Soil and Sediment, 129–50. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4757-9969-9_8.

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Gagan, Michael K., and Nerilie J. Abram. "Stable Isotopes and Trace Elements." In Encyclopedia of Modern Coral Reefs, 1034–43. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-2639-2_27.

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Violante, Sara, Mirela Berisa, Tiffany H. Thomas, and Justin R. Cross. "Stable Isotope Tracers for Metabolic Pathway Analysis." In High-Throughput Metabolomics, 269–83. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9236-2_17.

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Coplen, Tyler B., Andrew L. Herczeg, and Chris Barnes. "Isotope Engineering—Using Stable Isotopes of the Water Molecule to Solve Practical Problems." In Environmental Tracers in Subsurface Hydrology, 79–110. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-4557-6_3.

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Schwarcz, H. P., and M. J. Schoeninger. "Stable Isotopes of Carbon and Nitrogen as Tracers for Paleo-Diet Reconstruction." In Advances in Isotope Geochemistry, 725–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-10637-8_34.

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Bullen, Thomas D. "Stable Isotopes of Transition and Post-Transition Metals as Tracers in Environmental Studies." In Advances in Isotope Geochemistry, 177–203. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-10637-8_10.

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Conference papers on the topic "Stable isotope tracer"

1

Sánchez-Murillo, Ricardo. "Tracer hydrology of the data-scarce and heterogeneous Central American Isthmus." In I Congreso Internacional de Ciencias Exactas y Naturales. Universidad Nacional, 2019. http://dx.doi.org/10.15359/cicen.1.36.

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Numerous socio-economic activities depend on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Population growth and unregulated land use changes resulted in extensive surface water pollution and a large dependency on groundwater resources. This chapter uses stable isotope variations in rainfall, surface water, and groundwater of Costa Rica, Nicaragua, El Salvador, and Honduras to develop a regionalized rainfall isoscape, isotopic lapse rates, spatial-temporal isotopic variations, and air mass back trajectories determining potential mean recharge elevations, moisture circulation patterns, and surface water-groundwater interactions. Intra-seasonal rainfall modes resulted in two isotopically depleted incursions (W-shaped isotopic pattern) during the wet season and two enriched pulses during the Mid-Summer Drought and the months of the strongest trade winds. Notable isotopic sub-cloud fractionation and near-surface secondary evaporation were identified as common denominators within the Central American Dry Corridor. Groundwater and surface water isotope ratios depicted the strong orographic separation into the Caribbean and Pacific domains, mainly induced by the governing moisture transport from the Caribbean Sea, complex rainfall producing systems across the N-S mountain range, and the subsequent mixing with local evapotranspiration, and, to a lesser degree, the eastern Pacific Ocean fluxes. Groundwater recharge was characterized by a) depleted recharge in highland areas (72.3%), b) rapid recharge via preferential flow paths (13.1%), and enriched recharge due to near-surface secondary fractionation (14.6%). Median recharge elevation ranged from 1,104 to 1,979 m a.s.l. These results are intended to enhance forest conservation practices, inform water protection regulations, and facilitate water security and sustainability planning in the Central American Isthmus.

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Zimmermann, Tristan, Ole Klein, Anna Reese, Fwziah Mohamed, Michael Wieser, Johanna Irrgeher, and Daniel Pröfrock. "“Non-Traditional” Stable Isotope Analysis as Tracer so Identify Sources and Sinks of Inorganic Contaminants in Riverine Environments." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.3228.

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Zhao, Yanrong, Fenggen Yang, Jinchuan Guo, and Ronghui Li. "Study on the Influence of Fast-growing Eucalyptus Planting on Reservoir Water Quality in Guangxi Based on N Stable Isotope Tracer Technology." In 5th International Conference on Civil Engineering and Transportation. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/iccet-15.2015.153.

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Rossegger, Bernhard, Michael Engelmayer, and Andreas Wimmer. "Challenges in Measuring Lube Oil Consumption of Internal Combustion Engines Using Deuterium As a Tracer." In ASME 2019 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/icef2019-7111.

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Abstract Lube oil emission is thought to have a negative influence on hydrocarbon and particle emissions, autoignition and the life-cycle cost of internal combustion engines. Thus, one of the major goals of combustion engine research and development is to optimize lube oil consumption, for example by optimizing the tribological behavior of the piston group (interaction between piston rings and cylinder liner). This requires the application of a fast and accurate lube oil consumption measurement method. Methods such as gravimetric and volumetric measurement are outdated for R&D applications because of measurement time, absolute accuracy as well as repeatability, however some OEMs are still applying this method. At present, the use of tracer methods for measuring lube oil consumption is considered the most promising in terms of decreasing measurement time and increasing accuracy. For example, sulfur as a tracer is one of the most established methods for measuring lube oil consumption, but previous publications have revealed downsides and future challenges of its use. This publication, however, highlights the challenges of using the stable hydrogen isotope deuterium as a tracer which are still to overcome, in order to become a viable and reliable method for measuring lube oil consumption on internal combustion engines. In the introduction, a novel concept of measuring lube oil consumption with deuterated engine oil and the test bench setup are explained. Following laboratory experiments, test bench runs on a heavy-duty diesel engine and long-term studies on a field engine, three major challenges facing the new approach are identified and potential solutions are proposed. First, the long-term stability of the tracer in the lube oil and potential changes in the physical and chemical properties of the oil due to deuteration are discussed in light of the results of tests on a field engine that uses deuterated engine oil. Second, the hydrogen-deuterium exchange process to mark the oil with the tracer is examined and potential approaches for reducing cost and duration are highlighted. The universal applicability of the deuteration process to several base oil groups is also explained. Finally, the detection of deuterium in the gas of the engine exhaust and potential cross-sensitivities to trace gases as well as other crucial limitations of the detector in analyzing engine exhaust are addressed. The summary presents the requirements for converting the experiments with a deuterium tracer into a reliable method for lube oil consumption measurement providing crucial properties such as high accuracy, short measurement time, effort and ease of use.

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Ishii, Tasuku, Daisuke Akiyama, Akira Kirishima, Nobuaki Sato, and Tadashi Narabayashi. "Sorption of Radioactive Methyl Iodide by Silver Doped Zeolite for Filtered Venting System." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60819.

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Filtered containment venting system (FCVS) is an emergency response system for severe accident. FCVS reduces the pressure in reactor vessel and removes radioactive iodine and cesium. Recently, silver doped zeolite (AgX) has been attracting attentions since it is believed to remove over 99.99% of CH3I in the ventilation gas. However, the reliable data of AgX for CH3I sorption under expected severe accident conditions are still limited. Therefore, the sorption behavior of CH3I on AgX was investigated under several expected conditions. In this study, the CH3I labeled by 125I tracer was synthesized by isotope exchange reaction, and it was devoted for sorption experiment on AgX. Sorption experiment using stable CH3I was also conducted by the same procedure. From results of the sorption experiment, over 99.9% of 2.28g of CH3I were sorbed by 10g of AgX. After the sorption experiment, AgX samples were analyzed by powder X-ray diffraction (XRD) and SEM–EDX. These results indicated the distribution of Ag agreed with that of I in micro area of AgX. For the evaluation of apparent sorption capacity of AgX, breaking through experiment was carried out. The apparent sorption capacity of AgX for CH3I was determined as 0.25g / g (AgX) at 24°C. The breaking through experiment was also carried out for the evaluation of CH3I flux and humidity effects in the vent gas. The effect of temperature on the sorption capacity was also studied. When the flux of CH3I supply was increased from 1.09 × 10−4 to 2.33 × 10−4g/cm2s, apparent sorption capacity was unchanged (= 0.21g / g (AgX)). Besides, the apparent sorption capacity was unchanged in the humidity range of ∼0 % H2O to 0.01 % H2O, while it decreased to 0.19 g / g (AgX) at 3% H2O. When sorption temperature increased to 170 °C, the apparent sorption capacity also increased to 0.69 g / g (AgX).

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Aldahik, A. "Trace Origin of Gas Leakage behind Casing Using Stable Isotope Geochemistry." In EAGE Workshop on Petroleum Geochemistry in Operations and Production. Netherlands: EAGE Publications BV, 2016. http://dx.doi.org/10.3997/2214-4609.201602333.

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Moxley, Nathan, C. Kent Keller, Richard M. Conrey, and James L. Osiensky. "STABLE ISOTOPES OF HYDROGEN AND OXYGEN: HYDROLOGIC TRACERS OF AQUIFER RECHARGE." In 68th Annual Rocky Mountain GSA Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016rm-276104.

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Magdas, D. A., A. Dehelean, R. Puscas, G. Cristea, F. Tusa, C. Voica, and Mihaela D. Lazar. "The quality control of fruit juices by using the stable isotope ratios and trace metal elements concentrations." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2011). AIP, 2012. http://dx.doi.org/10.1063/1.3681996.

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Treuhaft, Martin B., Suzanne A. Timmons, Douglas C. Eberle, and Glenn R. Wendel. "Wear Measurement of a Large Hydraulic Fluid Power Pump Using Radioactive Tracer Wear Technology." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42805.

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Real-time wear measurement is possible in fluid lubricated components utilizing radioactive tracer technology (RATT). This technology has been applied to internal combustion engines since the 1950’s, but has only recently been applied to hydraulic components. This paper presents the application of radioactive tracer technology to measure wear rate of pistons and slippers in a large variable displacement, high pressure, axial piston pump under various operating conditions. To apply this technology, new piston and slipper assemblies were exposed to thermal neutrons in a nuclear reactor to produce characteristic radionuclides (isotopes) in the slippers and pistons. These isotopes act as tracers, which when worn off in an operating pump can be measured by monitoring the gamma-ray activity in the circulating fluid. The accumlation of wear particles in the unfiltered circulation loop is monitored continuously as the pump is operated under various transient and steady state conditions. The steady state wear rate is determined by the rate of accumulation of radioactive wear particles in the loop over a period of time, usually less than a few hours. This first time application of RATT for wear analysis in a large hydraulic pump has shown positive results. This technology can be applied to determine wear sensitivity of hydraulic pump parts for an endless array of factors, such as speed, pressure, displacement, temperature, contamination level and composition, and duty cycle. Break-in, start-up, and transient wear affects can also be observed. Comparisons can also be made between the wear of different design features and materials.

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Sun, Ramon C., Marc O. Warmoes, Ye Yang, Pan Deng, Qiushi Sun, Andrew N. Lane, Richard M. Higashi, and Teresa W.-M. Fan. "Abstract 2502: Liquid diet introduction of tracers into mice for stable isotope-resolved metabolomics (SIRM) investigations." In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-2502.

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Reports on the topic "Stable isotope tracer"

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Luong, Elise. Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems. Office of Scientific and Technical Information (OSTI), May 1999. http://dx.doi.org/10.2172/355038.

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Marks, N. E., L. E. Borg, G. R. Eppich, A. M. Gaffney, V. G. Genneti, I. D. Hutcheon, M. J. Kristo, et al. Technical Report on the Behavior of Trace Elements, Stable Isotopes, and Radiogenic Isotopes During the Processing of Uranium Ore to Uranium Ore Concentrate. Office of Scientific and Technical Information (OSTI), July 2015. http://dx.doi.org/10.2172/1243009.

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Use of stable carbon and nitrogen isotopes to trace the larval striped bass food chain in the Sacramento-San Joaquin Estuary, California, April to September 1985. US Geological Survey, 1989. http://dx.doi.org/10.3133/wri884164.

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