Tracer kinetic modelling of receptor data with mathematical metabolite correction

International Nuclear Information System (INIS)

Burger, C.; Buck, A.

1996-01-01

Quantitation of metabolic processes with dynamic positron emission tomography (PET) and tracer kinetic modelling relies on the time course of authentic ligand in plasma, i.e. the input curve. The determination of the latter often requires the measurement of labelled metabilites, a laborious procedure. In this study we examined the possibility of mathematical metabolite correction, which might obviate the need for actual metabolite measurements. Mathematical metabilite correction was implemented by estimating the input curve together with kinetic tissue parameters. The general feasibility of the approach was evaluated in a Monte Carlo simulation using a two tissue compartment model. The method was then applied to a series of five human carbon-11 iomazenil PET studies. The measured cerebral tissue time-activity curves were fitted with a single tissue compartment model. For mathematical metabolite correction the input curve following the peak was approximated by a sum of three decaying exponentials, the amplitudes and characteristic half-times of which were then estimated by the fitting routine. In the simulation study the parameters used to generate synthetic tissue time-activity curves (K 1 -k 4 ) were refitted with reasonable identifiability when using mathematical metabolite correciton. Absolute quantitation of distribution volumes was found to be possible provided that the metabolite and the kinetic models are adequate. If the kinetic model is oversimplified, the linearity of the correlation between true and estimated distribution volumes is still maintained, although the linear regression becomes dependent on the input curve. These simulation results were confirmed when applying mathematical metabolite correction to the 11 C iomazenil study. Estimates of the distribution volume calculated with a measured input curve were linearly related to the estimates calculated using mathematical metabolite correction with correlation coefficients >0.990. (orig./MG)

Kinetic Modelling of Infection Tracers [¹⁸F]FDG, [⁶⁸Ga]Ga-Citrate, [¹¹C]Methionine, and [¹¹C]Donepezil in a Porcine Osteomyelitis Model

DEFF Research Database (Denmark)

Jødal, Lars; Jensen, Svend Borup; Nielsen, Ole Lerberg

2017-01-01

Introduction. Positron emission tomography (PET) is increasingly applied for infection imaging using [18F]FDG as tracer, but uptake is unspecific. The present study compares the kinetics of [18F]FDG and three other PET tracers with relevance for infection imaging. Methods. A juvenile porcine...... osteomyelitis model was used. Eleven pigs underwent PET/CT with 60-minute dynamic PET imaging of [18F]FDG, [68Ga]Ga-citrate, [11C]methionine, and/or [11C]donepezil, along with blood sampling. For infectious lesions, kinetic modelling with one- and two-tissue-compartment models was conducted for each tracer...... for the analysis. Conclusions. The kinetics of the four studied tracers in infection was characterized. For clinical applications, [18F]FDG remains the first-choice PET tracer. [11C]methionine may have a potential for detecting soft tissue infections. [68Ga]Ga-citrate and [11C]donepezil were not found useful...

Tracer kinetics of plants carbon allocation with continuously produced 11CO2

International Nuclear Information System (INIS)

Fares, Y.; Goeschl, J.D.; Magnuson, C.E.; Strain, B.R.

1988-01-01

Parameters of carbon allocation dynamics in plants were measured using 11 CO 2 and tracer kinetics techniques. Mechanical agitation reduced carbon export rate (CER) by 33% in cotton seedling's leaf, while storage rate and export pool size increased. Carbon storage and export rates of C 4 bunch grasses were higher in the afternoon than in the morning in spite of the decrease in CER. Water stress of cotton seedlings caused reduction in CER, and increase in exportable products concentrations and rate of storage. By the third stress day, measurable decreases in CER, transpiration, export rate and export pool size were recorded. (author) 17 refs.; 8 figs.; 1 tab

Differential equation methods for simulation of GFP kinetics in non-steady state experiments.

Science.gov (United States)

Phair, Robert D

2018-03-15

Genetically encoded fluorescent proteins, combined with fluorescence microscopy, are widely used in cell biology to collect kinetic data on intracellular trafficking. Methods for extraction of quantitative information from these data are based on the mathematics of diffusion and tracer kinetics. Current methods, although useful and powerful, depend on the assumption that the cellular system being studied is in a steady state, that is, the assumption that all the molecular concentrations and fluxes are constant for the duration of the experiment. Here, we derive new tracer kinetic analytical methods for non-steady state biological systems by constructing mechanistic nonlinear differential equation models of the underlying cell biological processes and linking them to a separate set of differential equations governing the kinetics of the fluorescent tracer. Linking the two sets of equations is based on a new application of the fundamental tracer principle of indistinguishability and, unlike current methods, supports correct dependence of tracer kinetics on cellular dynamics. This approach thus provides a general mathematical framework for applications of GFP fluorescence microscopy (including photobleaching [FRAP, FLIP] and photoactivation to frequently encountered experimental protocols involving physiological or pharmacological perturbations (e.g., growth factors, neurotransmitters, acute knockouts, inhibitors, hormones, cytokines, and metabolites) that initiate mechanistically informative intracellular transients. When a new steady state is achieved, these methods automatically reduce to classical steady state tracer kinetic analysis. © 2018 Phair. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Kinetic analysis of 18F-fluorodihydrorotenone as a deposited myocardial flow tracer: Comparison to thallium-201.

Energy Technology Data Exchange (ETDEWEB)

Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; O' Neil, James P.; La Belle, Michael; Huesman, Ronald H.; VanBrocklin, Henry F.

2004-03-01

The goal of this investigation was to assess the accuracy of 18F-fluorodihydrorotenone (18F-FDHR) as a new deposited myocardial flow tracer and compare the results to those for 201Tl. Methods. The kinetics of these flow tracers were evaluated in 22 isolated, erythrocyte- and albumin-perfused rabbit hearts over a flow range encountered in patients. The two flow tracers plus a vascular reference tracer (131I-albumin) were introduced as a bolus through a port just above the aortic cannula. Myocardial extraction, retention, washout, and uptake parameters were computed from the venous outflow curves using the multiple indicator dilution technique and spectral analysis. Results. The mean initial extraction fractions of 18F-FDHR (0.85 +- 0.07) and 201Tl (0.87 +- 0.05) were not significantly different, although the initial extraction fraction for 18F-FDHR declined with flow (P < 0.0001), whereas the initial extraction fraction of 201Tl did not. Washout of 201Tl was faster (P < 0.001) and more affected by flow (P < 0.05) than 18F-FDHR washout. Except for initial extraction fraction, 18F-FDHR retention was greater (P < 0.001) and less affected by flow (P < 0.05) than 201Tl retention. Reflecting its superior retention, net uptake of 18F-FDHR was better correlated with flow than 201Tl uptake at both one and fifteen minutes after tracer introduction (P < 0.0001 for both comparisons). Conclusion. The superior correlation of 18F-FDHR uptake with flow indicates that it is a better flow tracer than 201Tl in the isolated rabbit heart. Compared to the other currently available positron-emitting flow tracers (82Rb, 13N-ammonia, and 15O-water), 18F-FDHR has the potential of providing excellent image resolution without the need for an on-site cyclotron.

Quantitative dynamic ¹⁸FDG-PET and tracer kinetic analysis of soft tissue sarcomas.

Science.gov (United States)

Rusten, Espen; Rødal, Jan; Revheim, Mona E; Skretting, Arne; Bruland, Oyvind S; Malinen, Eirik

2013-08-01

To study soft tissue sarcomas using dynamic positron emission tomography (PET) with the glucose analog tracer [(18)F]fluoro-2-deoxy-D-glucose ((18)FDG), to investigate correlations between derived PET image parameters and clinical characteristics, and to discuss implications of dynamic PET acquisition (D-PET). D-PET images of 11 patients with soft tissue sarcomas were analyzed voxel-by-voxel using a compartment tracer kinetic model providing estimates of transfer rates between the vascular, non-metabolized, and metabolized compartments. Furthermore, standard uptake values (SUVs) in the early (2 min p.i.; SUVE) and late (45 min p.i.; SUVL) phases of the PET acquisition were obtained. The derived transfer rates K1, k2 and k3, along with the metabolic rate of (18)FDG (MRFDG) and the vascular fraction νp, was fused with the computed tomography (CT) images for visual interpretation. Correlations between D-PET imaging parameters and clinical parameters, i.e. tumor size, grade and clinical status, were calculated with a significance level of 0.05. The temporal uptake pattern of (18)FDG in the tumor varied considerably from patient to patient. SUVE peak was higher than SUVL peak for four patients. The images of the rate constants showed a systematic pattern, often with elevated intensity in the tumors compared to surrounding tissue. Significant correlations were found between SUVE/L and some of the rate parameters. Dynamic (18)FDG-PET may provide additional valuable information on soft tissue sarcomas not obtainable from conventional (18)FDG-PET. The prognostic role of dynamic imaging should be investigated.

Kinetic modeling in PET imaging of hypoxia

Science.gov (United States)

Li, Fan; Joergensen, Jesper T; Hansen, Anders E; Kjaer, Andreas

2014-01-01

Tumor hypoxia is associated with increased therapeutic resistance leading to poor treatment outcome. Therefore the ability to detect and quantify intratumoral oxygenation could play an important role in future individual personalized treatment strategies. Positron Emission Tomography (PET) can be used for non-invasive mapping of tissue oxygenation in vivo and several hypoxia specific PET tracers have been developed. Evaluation of PET data in the clinic is commonly based on visual assessment together with semiquantitative measurements e.g. standard uptake value (SUV). However, dynamic PET contains additional valuable information on the temporal changes in tracer distribution. Kinetic modeling can be used to extract relevant pharmacokinetic parameters of tracer behavior in vivo that reflects relevant physiological processes. In this paper, we review the potential contribution of kinetic analysis for PET imaging of hypoxia. PMID:25250200

Tracer kinetics: Modelling by partial differential equations of inhomogeneous compartments with age-dependent elimination rates. Pt. 1

International Nuclear Information System (INIS)

Winkler, E.

1991-01-01

Mathematical models in tracer kinetics are usually based on ordinary differential equations which correspond to a system of kinetically homogeneous compartments (standard compartments). A generalization is possible by the admission of inhomogeneities in the behaviour of the elements belonging to a compartment. The important special case of the age-dependence of elimination rates is treated in its deterministic version. It leads to partial different equations (i.e., systems with distributed coefficients) with the 'age' or the 'residence time' of an element of the compartment as a variable additional to 'time'. The basic equations for one generalized compartment and for systems of such compartments are given together with their general solutions. (orig.) [de

Cesium removal and kinetics equilibrium: Precipitation kinetics

International Nuclear Information System (INIS)

Barnes, M.J.

1999-01-01

This task consisted of both non-radioactive and radioactive (tracer) tests examining the influence of potentially significant variables on cesium tetraphenylborate precipitation kinetics. The work investigated the time required to reach cesium decontamination and the conditions that affect the cesium precipitation kinetics

Rapid dual-tracer PTSM+ATSM PET imaging of tumour blood flow and hypoxia: a simulation study

International Nuclear Information System (INIS)

Rust, T C; Kadrmas, D J

2006-01-01

Blood flow and hypoxia are interrelated aspects of physiology that affect cancer treatment and response. Cu-PTSM and Cu-ATSM are related PET tracers for blood flow and hypoxia, and the ability to rapidly image both tracers in a single scan would bring several advantages over conventional single-tracer techniques. Using dynamic imaging with staggered injections, overlapping signals for multiple PET tracers may be recovered utilizing information from kinetics and radioactive decay. In this work, rapid dual-tracer PTSM+ATSM PET was simulated and tested as a function of injection delay, order and relative dose for several copper isotopes, and the results were compared relative to separate single-tracer data. Time-activity curves representing a broad range of tumour blood flow and hypoxia levels were simulated, and parallel dual-tracer compartment modelling was used to recover the signals for each tracer. The main results were tested further using a torso phantom simulation of PET tumour imaging. Using scans as short as 30 minutes, the dual-tracer method provided measures of blood flow and hypoxia similar to single-tracer imaging. The best performance was obtained by injecting PTSM first and using a somewhat higher dose for ATSM. Comparable results for different copper isotopes suggest that tracer kinetics with staggered injections play a more important role than radioactive decay in the signal separation process. Rapid PTSM+ATSM PET has excellent potential for characterizing both tumour blood flow and hypoxia in a single, fast scan, provided that technological hurdles related to algorithm development and routine use can be overcome

Kinetic modelling of [123I]CNS 1261--a potential SPET tracer for the NMDA receptor

International Nuclear Information System (INIS)

Erlandsson, Kjell; Bressan, Rodrigo A.; Mulligan, Rachel S.; Gunn, Roger N; Cunningham, Vincent J.; Owens, Jonathan; Wyper, David; Ell, Peter J.; Pilowsky, Lyn S.

2003-01-01

N-(1-napthyl)-N'-(3-[ 123 I]-iodophenyl)-N-methylguanidine ([ 123 I]CNS 1261) is a novel SPET ligand developed for imaging the NMDA receptor intra-channel MK 801/PCP/ketamine site. Data was acquired in 7 healthy volunteers after bolus injection of [ 123 I]CNS 1261. Kinetic modeling showed reversible tracer binding. Arterial and venous time-activity curves overlapped after 90 min. The rank order of binding was: Thalamus > striatum > cortical regions > white matter. This distribution concurs with [ 11 C]-ketamine and [ 18 F]-memantine PET studies . These data provide a methodological basis for further direct in vivo challenge studies

Tracer kinetics: Modelling by partial differential equations of inhomogeneous compartments with age-dependent elimination rates. Pt. 2

International Nuclear Information System (INIS)

Winkler, E.

1991-01-01

The general theory of inhomogeneous compartments with age-dependent elimination rates is illustrated by examples. Mathematically, it turns out that models consisting of partial differential equations include ordinary, delayed and integro-differential equations, a general fact which is treated here in the context of linear tracer kinetics. The examples include standard compartments as a degenerate case, systems of standard compartments (compartment blocks), models resulting in special residence time distributions, models with pipes, and systems with heterogeneous particles. (orig./BBR) [de

WE-FG-206-06: Dual-Input Tracer Kinetic Modeling and Its Analog Implementation for Dynamic Contrast-Enhanced (DCE-) MRI of Malignant Mesothelioma (MPM)

Energy Technology Data Exchange (ETDEWEB)

Lee, S; Rimner, A; Hayes, S; Hunt, M; Deasy, J; Zauderer, M; Rusch, V; Tyagi, N [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

2016-06-15

Purpose: To use dual-input tracer kinetic modeling of the lung for mapping spatial heterogeneity of various kinetic parameters in malignant MPM Methods: Six MPM patients received DCE-MRI as part of their radiation therapy simulation scan. 5 patients had the epitheloid subtype of MPM, while one was biphasic. A 3D fast-field echo sequence with TR/TE/Flip angle of 3.62ms/1.69ms/15° was used for DCE-MRI acquisition. The scan was collected for 5 minutes with a temporal resolution of 5-9 seconds depending on the spatial extent of the tumor. A principal component analysis-based groupwise deformable registration was used to co-register all the DCE-MRI series for motion compensation. All the images were analyzed using five different dual-input tracer kinetic models implemented in analog continuous-time formalism: the Tofts-Kety (TK), extended TK (ETK), two compartment exchange (2CX), adiabatic approximation to the tissue homogeneity (AATH), and distributed parameter (DP) models. The following parameters were computed for each model: total blood flow (BF), pulmonary flow fraction (γ), pulmonary blood flow (BF-pa), systemic blood flow (BF-a), blood volume (BV), mean transit time (MTT), permeability-surface area product (PS), fractional interstitial volume (vi), extraction fraction (E), volume transfer constant (Ktrans) and efflux rate constant (kep). Results: Although the majority of patients had epitheloid histologies, kinetic parameter values varied across different models. One patient showed a higher total BF value in all models among the epitheloid histologies, although the γ value was varying among these different models. In one tumor with a large area of necrosis, the TK and ETK models showed higher E, Ktrans, and kep values and lower interstitial volume as compared to AATH and DP and 2CX models. Kinetic parameters such as BF-pa, BF-a, PS, Ktrans values were higher in surviving group compared to non-surviving group across most models. Conclusion: Dual-input tracer

Multiple stable isotope tracer technique for studying the metabolic kinetics of amino acids in hepatic failure

Energy Technology Data Exchange (ETDEWEB)

Zongqin, Xia; Tengchang, Dai; Jianhua, Zhang; Yaer, Hu; Bingyao, Yu; Xingrong, Xu; Guanlu, Huang; Gengrong, Shen; Yaqiu, Zhou; Hong, Yu

1987-08-01

In order to study the mechanism of the imbalance of amino acid metabolism during hepatic failure, a stable isotope tracer method for observing simultaneously the metabolic kinetics of several amino acids has been established. /sup 15/N-L-Ala, (2,3-D/sub 3/)-Leu and (2,3-D/sub 3/)-Phe were chosen as nonessential, branched chain and aromatic amino acids. A single iv injection of 40 mg N-Ala, 20 mg deuterated Leu and 20 mg deuterated Phe was given to each human subject. Blood samples were taken just before and at different times (up to 60 min) after the injection. Total free amino acids were isolated from the plasma with a small dowex 50 x 8 column and converted to trifluoroacetyl derivatives. Their abundances were then analyzed with a GC-MS system and typical double exponential time course curves were found for all the three labelled amino acids. A two-pool model was designed and applied for compartmental analysis. Significant changes were found in the kinetic parameters of Phe and Leu in patients with fulminant hepatitis or heptic cirrhosis. The half-lives of both Phe pools were longer and the pool sizes were larger than normal subjects, while the half-lives and pool sizes of Leu changes in the opposite direction. No marked change was found in Ala. The significance of intracellular imbalance of Phe and Leu metabolism was discussed. It is evident that the combination of GCMS technique and multiple-tracers labelled with stable isotopes is of great potential for similar purposes.

Continuous administration of short-lived radioisotope tracers and the analogous Laplace transform

International Nuclear Information System (INIS)

Orr, J.S.

1979-01-01

Short-lived radioactive tracers are used because of the low radiation dose to patients. Another advantage finding increasing use, however, is that the equilibrium activities achieved by continuous administration to a steady state contain kinetic information. This is not the case with long-lived isotopes. The derivation of quantitative kinetic information in the form of rate constants or flows requires the formulation of a model of the system being studied. Several approaches to this have been published based on a model of single compartments with simultaneous arrival of tracer. To deal with more realistic models a method is proposed which uses the analogy between the procedure of continuous administration of short-lived tracer and the Laplace transform. This analogy permits all the theorems of Laplace transform theory to be applied to the analysis of measured activities. The basis of the analogy is explained and examples are given of its application to a number of models which represent actual physiology more realistically than single compartment models. In these applications the transformed equations representing the model, with measured values of activity inserted for each transform, are solved to derive the rate constants. This is different from the use of Laplace transforms where the constant coefficients are known and the initial value problem is solved to find the behaviour of the variables. (author)

Laboratory and numerical investigations of kinetic interface sensitive tracers transport for immiscible two-phase flow porous media systems

Science.gov (United States)

Tatomir, Alexandru Bogdan A. C.; Sauter, Martin

2017-04-01

A number of theoretical approaches estimating the interfacial area between two fluid phases are available (Schaffer et al.,2013). Kinetic interface sensitive (KIS) tracers are used to describe the evolution of fluid-fluid interfaces advancing in two phase porous media systems (Tatomir et al., 2015). Initially developed to offer answers about the supercritical (sc)CO2 plume movement and the efficiency of trapping in geological carbon storage reservoirs, KIS tracers are tested in dynamic controlled laboratory conditions. N-octane and water, analogue to a scCO2 - brine system, are used. The KIS tracer is dissolved in n-octane, which is injected as the non-wetting phase in a fully water saturated porous media column. The porous system is made up of spherical glass beads with sizes of 100-250 μm. Subsequently, the KIS tracer follows a hydrolysis reaction over the n-octane - water interface resulting in an acid and phenol which are both water soluble. The fluid-fluid interfacial area is described numerically with the help of constitutive-relationships derived from the Brooks-Corey model. The specific interfacial area is determined numerically from pore scale calculations, or from different literature sources making use of pore network model calculations (Joekar-Niasar et al., 2008). This research describes the design of the laboratory setup and compares the break-through curves obtained with the forward model and in the laboratory experiment. Furthermore, first results are shown in the attempt to validate the immiscible two phase flow reactive transport numerical model with dynamic laboratory column experiments. Keywords: Fluid-fluid interfacial area, KIS tracers, model validation, CCS, geological storage of CO2

Tracer disposition kinetics in the determination of local cerebral blood flow by a venous equilibrium model, tube model, and distributed model

International Nuclear Information System (INIS)

Sawada, Y.; Sugiyama, Y.; Iga, T.; Hanano, M.

1987-01-01

Tracer distribution kinetics in the determination of local cerebral blood flow (LCBF) were examined by using three models, i.e., venous equilibrium, tube, and distributed models. The technique most commonly used for measuring LCBF is the tissue uptake method, which was first developed and applied by Kety. The measurement of LCBF with the 14 C-iodoantipyrine (IAP) method is calculated by using an equation derived by Kety based on the Fick's principle and a two-compartment model of blood-tissue exchange and tissue concentration at a single data point. The procedure, in which the tissue is to be in equilibrium with venous blood, will be referred to as the tissue equilibration model. In this article, effects of the concentration gradient of tracer along the length of the capillary (tube model) and the transverse heterogeneity in the capillary transit time (distributed model) on the determination of LCBF were theoretically analyzed for the tissue sampling method. Similarities and differences among these models are explored. The rank order of the LCBF calculated by using arterial blood concentration time courses and the tissue concentration of tracer based on each model were tube model (model II) less than distributed model (model III) less than venous equilibrium model (model I). Data on 14 C-IAP kinetics reported by Ohno et al. were employed. The LCBFs calculated based on model I were 45-260% larger than those in models II or III. To discriminate among three models, we propose to examine the effect of altering the venous infusion time of tracer on the apparent tissue-to-blood concentration ratio (lambda app). A range of the ratio of the predicted lambda app in models II or III to that in model I was from 0.6 to 1.3

Measurement of cardiovascular function using a novel view-sharing PET reconstruction method and tracer kinetic analysis

Directory of Open Access Journals (Sweden)

Paul R. Territo

2016-10-01

Full Text Available Abstract Recent advancements in PET instrumentation have made the non-invasive assessment of cardiovascular function in small animals a reality. The majority of small animal PET systems use stationary detector gantries, thus affording high temporal resolution imaging of cardiac function. Systems designed to maximize spatial resolution and detection sensitivity employing rotating gantry designs are suboptimal when high temporal resolution imaging is needed. To overcome this limitation, the current work developed a novel view-sharing data analysis scheme suitable for dynamic cardiac PET imaging using 18F-NaF as the tracer and tracer kinetic model analysis. This scheme was tested in a rat model of cardiovascular function where the relationship between direct transonic flow measures of cardiac output were highly correlated (f(x = 1.0216x − 24.233, R = 0.9158, p < 0.001 with the new model. Similarly, derived measures of stroke volume were also highly correlated (f(x = 0.9655x − 0.0428, R = 0.9453, p < 0.001 with the current approach. Administration of xylazine caused a statistically significant increase in stroke volume (0.32 ± 0.07 ml, p = 0.003, n = 4 and a significant decrease in both heart rate (−155 ± 7.1 beats/min, p < 0.001, n = 4 and cardiac output (−75.9 ± 23.0 ml/kg min, p = 0.01, n = 4. These findings suggest that the new sinogram binning and kinetic modeling methods produce reliable cardiac function measures suitable for longitudinal monitoring of cardiovascular function.

Kinetic modelling of [{sup 123}I]CNS 1261--a potential SPET tracer for the NMDA receptor

Energy Technology Data Exchange (ETDEWEB)

Erlandsson, Kjell E-mail: k.erlandsson@nucmed.ucl.ac.uk; Bressan, Rodrigo A.; Mulligan, Rachel S.; Gunn, Roger N; Cunningham, Vincent J.; Owens, Jonathan; Wyper, David; Ell, Peter J.; Pilowsky, Lyn S

2003-05-01

N-(1-napthyl)-N'-(3-[{sup 123}I]-iodophenyl)-N-methylguanidine ([{sup 123}I]CNS 1261) is a novel SPET ligand developed for imaging the NMDA receptor intra-channel MK 801/PCP/ketamine site. Data was acquired in 7 healthy volunteers after bolus injection of [{sup 123}I]CNS 1261. Kinetic modeling showed reversible tracer binding. Arterial and venous time-activity curves overlapped after 90 min. The rank order of binding was: Thalamus > striatum > cortical regions > white matter. This distribution concurs with [{sup 11}C]-ketamine and [{sup 18}F]-memantine PET studies . These data provide a methodological basis for further direct in vivo challenge studies.

Combining Empirical Relationships with Data Based Mechanistic Modeling to Inform Solute Tracer Investigations across Stream Orders

Science.gov (United States)

Herrington, C.; Gonzalez-Pinzon, R.; Covino, T. P.; Mortensen, J.

2015-12-01

Solute transport studies in streams and rivers often begin with the introduction of conservative and reactive tracers into the water column. Information on the transport of these substances is then captured within tracer breakthrough curves (BTCs) and used to estimate, for instance, travel times and dissolved nutrient and carbon dynamics. Traditionally, these investigations have been limited to systems with small discharges (turbidity (e.g., nitrate signals with SUNA instruments or fluorescence measures) and/or high total dissolved solids (e.g., making prohibitively expensive the use of salt tracers such as NaCl) in larger systems. Additionally, a successful time-of-travel study is valuable for only a single discharge and river stage. We have developed a method to predict tracer BTCs to inform sampling frequencies at small and large stream orders using empirical relationships developed from multiple tracer injections spanning several orders of magnitude in discharge and reach length. This method was successfully tested in 1st to 8th order systems along the Middle Rio Grande River Basin in New Mexico, USA.

Application of separable parameter space techniques to multi-tracer PET compartment modeling

International Nuclear Information System (INIS)

Zhang, Jeff L; Michael Morey, A; Kadrmas, Dan J

2016-01-01

Multi-tracer positron emission tomography (PET) can image two or more tracers in a single scan, characterizing multiple aspects of biological functions to provide new insights into many diseases. The technique uses dynamic imaging, resulting in time-activity curves that contain contributions from each tracer present. The process of separating and recovering separate images and/or imaging measures for each tracer requires the application of kinetic constraints, which are most commonly applied by fitting parallel compartment models for all tracers. Such multi-tracer compartment modeling presents challenging nonlinear fits in multiple dimensions. This work extends separable parameter space kinetic modeling techniques, previously developed for fitting single-tracer compartment models, to fitting multi-tracer compartment models. The multi-tracer compartment model solution equations were reformulated to maximally separate the linear and nonlinear aspects of the fitting problem, and separable least-squares techniques were applied to effectively reduce the dimensionality of the nonlinear fit. The benefits of the approach are then explored through a number of illustrative examples, including characterization of separable parameter space multi-tracer objective functions and demonstration of exhaustive search fits which guarantee the true global minimum to within arbitrary search precision. Iterative gradient-descent algorithms using Levenberg–Marquardt were also tested, demonstrating improved fitting speed and robustness as compared to corresponding fits using conventional model formulations. The proposed technique overcomes many of the challenges in fitting simultaneous multi-tracer PET compartment models. (paper)

Spectral analysis for evaluation of myocardial tracers for medical imaging

International Nuclear Information System (INIS)

Huesman, Ronald H.; Reutter, Bryan W.; Marshall, Robert C.

2000-01-01

Kinetic analysis of dynamic tracer data is performed with the goal of evaluating myocardial radiotracers for cardiac nuclear medicine imaging. Data from experiments utilizing the isolated rabbit heart model are acquired by sampling the venous blood after introduction of a tracer of interest and a reference tracer. We have taken the approach that the kinetics are properly characterized by an impulse response function which describes the difference between the reference molecule (which does not leave the vasculature) and the molecule of interest which is transported across the capillary boundary and is made available to the cell. Using this formalism we can model the appearance of the tracer of interest in the venous output of the heart as a convolution of the appearance of the reference tracer with the impulse response. In this work we parameterize the impulse response function as the sum of a large number of exponential functions whose predetermined decay constants form a spectrum, and each is required only to have a nonnegative coefficient. This approach, called spectral analysis, has the advantage that it allows conventional compartmental analysis without prior knowledge of the number of compartments which the physiology may require or which the data will support

Proceedings of Tracer 3. International Conference on Tracers and Tracing Methods

International Nuclear Information System (INIS)

2004-01-01

Tracer 3 conference is a continuation of former Tracer 1 (1998) and Tracer 2 (2001) conferences organized by CNRS - Nancy France. The objective of this 3rd conference is presentation of different aspects of tracer method applications and development of tracer methodology.The new field of activity presented at the Conference was application of stable isotopes as natural tracers for investigations of environmental processes. The conference gave the possibility for scientific information exchange between specialists from different fields of activity such as chemical engineering, chemistry, bioengineering, environmental engineering, hydrology, civil engineering, metallurgy, etc. The presentations were divided into groups covering the principal items of Conference. Section A. Fundamental development - RTD and tracer methodology, - RTD methodology and Computational Fluid Dynamics (CFD), - New tracers and detectors. Section B. Industrial applications - Environment, - Geology, hydrogeology and oil field applications, - Civil engineering, mineral engineering and metallurgy applications, - Food engineering and bioengineering, - Material engineering, - Chemical engineering. During the Conference INIS promotion materials were exposed by INIS liaison officer for Poland

Proceedings of Tracer 3. International Conference on Tracers and Tracing Methods

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

Tracer 3 conference is a continuation of former Tracer 1 (1998) and Tracer 2 (2001) conferences organized by CNRS - Nancy France. The objective of this 3rd conference is presentation of different aspects of tracer method applications and development of tracer methodology.The new field of activity presented at the Conference was application of stable isotopes as natural tracers for investigations of environmental processes. The conference gave the possibility for scientific information exchange between specialists from different fields of activity such as chemical engineering, chemistry, bioengineering, environmental engineering, hydrology, civil engineering, metallurgy, etc. The presentations were divided into groups covering the principal items of Conference. Section A. Fundamental development - RTD and tracer methodology, - RTD methodology and Computational Fluid Dynamics (CFD), - New tracers and detectors. Section B. Industrial applications - Environment, - Geology, hydrogeology and oil field applications, - Civil engineering, mineral engineering and metallurgy applications, - Food engineering and bioengineering, - Material engineering, - Chemical engineering. During the Conference INIS promotion materials were exposed by INIS liaison officer for Poland.

Compartmental modeling and tracer kinetics

CERN Document Server

Anderson, David H

1983-01-01

This monograph is concerned with mathematical aspects of compartmental an­ alysis. In particular, linear models are closely analyzed since they are fully justifiable as an investigative tool in tracer experiments. The objective of the monograph is to bring the reader up to date on some of the current mathematical prob­ lems of interest in compartmental analysis. This is accomplished by reviewing mathematical developments in the literature, especially over the last 10-15 years, and by presenting some new thoughts and directions for future mathematical research. These notes started as a series of lectures that I gave while visiting with the Division of Applied ~1athematics, Brown University, 1979, and have developed in­ to this collection of articles aimed at the reader with a beginning graduate level background in mathematics. The text can be used as a self-paced reading course. With this in mind, exercises have been appropriately placed throughout the notes. As an aid in reading the material, the e~d of a ...

Tracer studies of flotation in laboratory and plant

International Nuclear Information System (INIS)

Niemi, A.J.; Thereska, J.; Plasari, E.; Kacaj, M.

1992-01-01

Froth flotation is used for the industrial extraction of valuable minerals from ores. Its progress depends on the properties of minerals being processed and on flotation practices. While flotation is basically a kinetic process, it functions industrially in continuous flow vessels whose flow patterns influence the separation effected. Radioisotope tracers have proven to be a necessary tool in the acquisition of both kinetic and flow pattern data

Tracer investigations of macroprocesses in mineral processing. 1

International Nuclear Information System (INIS)

Koch, P.

1981-01-01

Results obtained from tracer studies in mineral processing have been evaluated with regard to the effects of hydrodynamic and design parameters of the single cell on flotation kinetics, to the residence time in single and in series-connected cells, and to the possibility of designing process control models. An algorithm is given for technological interpretation of results obtained from residence time and process kinetics studies

Clinical studies of bone metabolism using a simple model of calcium tracer kinetics

International Nuclear Information System (INIS)

Roncari, G.; Milan Univ., Varese

1981-01-01

Bone metabolism studies were performed in 44 subjects with and without bone disease using a calcium tracers kinetics model, the central feature of which is an expanding exchangeable calcium pool. In normal subjects the accretion rate and the exchangeable calcium pool ranged from 1.49 to 8.45 (mean 3.9 +- 2.05) mg.d -1 kg -1 and from 60 to 131 (mean 81.25 +- 18.11) mg.kg -1 , respectively. The patients with osteogenesis imperfecta, Pierre Marie's disease and one out of two cases of hypoparathyroidism had values which fell within the normal range. Both the accretion rate and the exchangeable calcium pool were significantly elevated in patients with Paget's disease and with hyperparathyroidism. Uremic patients with generalizated bone lesions had accretion rates or both parameters elevated. As far as patients with successful renal transplant are concerned, the results suggest that this method is a very poor means for detecting bone disorders with only focal lesions. In contrast, the method can be very useful when persistent renal osteodystrophy or secondary hyperparathyroidism are suspected. (orig.) [de

Clinical studies of bone metabolism using a simple model of calcium tracer kinetics

Energy Technology Data Exchange (ETDEWEB)

Roncari, G.

1981-08-01

Bone metabolism studies were performed in 44 subjects with and without bone disease using a calcium tracer kinetics model, the central feature of which is an expanding exchangeable calcium pool. In normal subjects the accretion rate and the exchangeable calcium pool ranged from 1.49 to 8.45 (mean 3.9 +- 2.05) mg.d/sup -1/kg/sup -1/ and from 60 to 131 (mean 81.25 +- 18.11) mg.kg/sup -1/, respectively. The patients with osteogenesis imperfecta, Pierre Marie's disease and one out of two cases of hypoparathyroidism had values which fell within the normal range. Both the accretion rate and the exchangeable calcium pool were significantly elevated in patients with Paget's disease and with hyperparathyroidism. Uremic patients with generalizated bone lesions had accretion rates or both parameters elevated. As far as patients with successful renal transplant are concerned, the results suggest that this method is a very poor means for detecting bone disorders with only focal lesions. In contrast, the method can be very useful when persistent renal osteodystrophy or secondary hyperparathyroidism are suspected.

Impact of contamination with long-lived radionuclides on PET kinetics modelling in multitracer studies

DEFF Research Database (Denmark)

Jødal, Lars; Hansen, Søren Baarsgaard; Jensen, Svend B

2016-01-01

Introduction: An important issue in multitracer studies is the separation of signals from the different radiotracers. This is especially the case when an early tracer has a long physical half-life and kinetic modelling has to be performed, because the early tracer can confer a long-lived contamin......Introduction: An important issue in multitracer studies is the separation of signals from the different radiotracers. This is especially the case when an early tracer has a long physical half-life and kinetic modelling has to be performed, because the early tracer can confer a long...... of subsequent PET tracers. Blood sample counts were corrected by recounting the samples a few days later. A more optimal choice of energy window was also explored. The effect of correction versus noncorrection was investigated using a two-tissue kinetic model with irreversible uptake (K1, k2, k3). Results: K1...... counting of blood samples can lead to a contaminating background not observed in PET imaging and this background can affect kinetic modelling. If the contaminating tracer has a much longer half-life than the foreground tracer, then the problem can be solved by late recounting of the samples....

Chemical Tracer Methods: Chapter 7

Science.gov (United States)

Healy, Richard W.

2017-01-01

Tracers have a wide variety of uses in hydrologic studies: providing quantitative or qualitative estimates of recharge, identifying sources of recharge, providing information on velocities and travel times of water movement, assessing the importance of preferential flow paths, providing information on hydrodynamic dispersion, and providing data for calibration of water flow and solute-transport models (Walker, 1998; Cook and Herczeg, 2000; Scanlon et al., 2002b). Tracers generally are ions, isotopes, or gases that move with water and that can be detected in the atmosphere, in surface waters, and in the subsurface. Heat also is transported by water; therefore, temperatures can be used to trace water movement. This chapter focuses on the use of chemical and isotopic tracers in the subsurface to estimate recharge. Tracer use in surface-water studies to determine groundwater discharge to streams is addressed in Chapter 4; the use of temperature as a tracer is described in Chapter 8.Following the nomenclature of Scanlon et al. (2002b), tracers are grouped into three categories: natural environmental tracers, historical tracers, and applied tracers. Natural environmental tracers are those that are transported to or created within the atmosphere under natural processes; these tracers are carried to the Earth’s surface as wet or dry atmospheric deposition. The most commonly used natural environmental tracer is chloride (Cl) (Allison and Hughes, 1978). Ocean water, through the process of evaporation, is the primary source of atmospheric Cl. Other tracers in this category include chlorine-36 (36Cl) and tritium (3H); these two isotopes are produced naturally in the Earth’s atmosphere; however, there are additional anthropogenic sources of them.

Circulation of cerebrospinal fluid. Comparative study of various tracers

International Nuclear Information System (INIS)

Bok, B.; Thebault, B.; Cavailloles, F.; Aboulker, J.

1977-01-01

The dynamics of cerebrospinal fluid in the spinal subarachnoid space is studied by gammamyelography. There are still controversies about the ideal properties of the tracer to be used. The influence of the tracer's molecular weight on the kinetic of ascent in the medullar cerebrospinal fluid with a view to rating the criterias for choice of an available radiopharmaceutical was evaluated. Three compounds injected simultaneously through a lombar puncture were compared: indium 111 labelled transferrin, iodine 131 labelled human serum albumin and technetium 99m labelled diethylenetriaminepentaacetic acid. The individual stability of the compounds and a possible interference between them was investigated especially by electrophoretic technics. A spectrometric study showed that it is possible to simultaneously identify and count each of the isotopes included in the mixture on the detector device: an hybrid scanner. The comparison of linear activity profils collected on phantoms and on ten patients showed a similar fate of the three compounds during the first hours of the investigation studying the ascent of tracers into basal cisterns either in normal or pathological patients. It is therefore concluded that molecular weight does not influence in a detectable manner the spinal C.S.F. kinetics of the radiopharmaceuticals. This allows the use of the most convenient and best tolerated tracer from the dosimetric and toxicological stand point [fr

Fisher information, kinetic energy and uncertainty relation inequalities

International Nuclear Information System (INIS)

Luo Shunlong

2002-01-01

By interpolating between Fisher information and mechanical kinetic energy, we introduce a general notion of kinetic energy with respect to a parameter of Schroedinger wavefunctions from a statistical inference perspective. Kinetic energy is the sum of Fisher information and an integral of a parametrized analogue of quantum mechanical current density related to phase. A family of integral inequalities concerning kinetic energy and moments are established, among which the Cramer-Rao inequality and the Weyl-Heisenberg inequality, are special cases. In particular, the integral inequalities involving the negative order moments are relevant to the study of electron systems. Moreover, by specifying the parameter to a scale, we obtain a family of inequalities of uncertainty relation type which incorporate the position and momentum observables symmetrically in a single quantity. (author)

Packet Tracer network simulator

CERN Document Server

Jesin, A

2014-01-01

A practical, fast-paced guide that gives you all the information you need to successfully create networks and simulate them using Packet Tracer.Packet Tracer Network Simulator is aimed at students, instructors, and network administrators who wish to use this simulator to learn how to perform networking instead of investing in expensive, specialized hardware. This book assumes that you have a good amount of Cisco networking knowledge, and it will focus more on Packet Tracer rather than networking.

Joint reconstruction of dynamic PET activity and kinetic parametric images using total variation constrained dictionary sparse coding

Science.gov (United States)

Yu, Haiqing; Chen, Shuhang; Chen, Yunmei; Liu, Huafeng

2017-05-01

Dynamic positron emission tomography (PET) is capable of providing both spatial and temporal information of radio tracers in vivo. In this paper, we present a novel joint estimation framework to reconstruct temporal sequences of dynamic PET images and the coefficients characterizing the system impulse response function, from which the associated parametric images of the system macro parameters for tracer kinetics can be estimated. The proposed algorithm, which combines statistical data measurement and tracer kinetic models, integrates a dictionary sparse coding (DSC) into a total variational minimization based algorithm for simultaneous reconstruction of the activity distribution and parametric map from measured emission sinograms. DSC, based on the compartmental theory, provides biologically meaningful regularization, and total variation regularization is incorporated to provide edge-preserving guidance. We rely on techniques from minimization algorithms (the alternating direction method of multipliers) to first generate the estimated activity distributions with sub-optimal kinetic parameter estimates, and then recover the parametric maps given these activity estimates. These coupled iterative steps are repeated as necessary until convergence. Experiments with synthetic, Monte Carlo generated data, and real patient data have been conducted, and the results are very promising.

Kinetic analysis of dynamic PET data

Energy Technology Data Exchange (ETDEWEB)

Knittel, B.

1983-12-01

Our goal is to quantify regional physiological processes such as blood flow and metabolism by means of tracer kinetic modeling and positron emission tomography (PET). Compartmental models are one way of characterizing the behavior of tracers in physiological systems. This paper describes a general method of estimating compartmental model rate constants from measurements of the concentration of tracers in blood and tissue, taken at multiple time intervals. A computer program which applies the method is described, and examples are shown for simulated and actual data acquired from the Donner 280-Crystal Positron Tomograph.

Kinetic analysis of dynamic PET data

International Nuclear Information System (INIS)

Knittel, B.

1983-12-01

Our goal is to quantify regional physiological processes such as blood flow and metabolism by means of tracer kinetic modeling and positron emission tomography (PET). Compartmental models are one way of characterizing the behavior of tracers in physiological systems. This paper describes a general method of estimating compartmental model rate constants from measurements of the concentration of tracers in blood and tissue, taken at multiple time intervals. A computer program which applies the method is described, and examples are shown for simulated and actual data acquired from the Donner 280-Crystal Positron Tomograph

Determination of steady state and nonsteady-state glycerol kinetics in humans using deuterium-labeled tracer

International Nuclear Information System (INIS)

Beylot, M.; Martin, C.; Beaufrere, B.; Riou, J.P.; Mornex, R.

1987-01-01

Using deuterium-labeled glycerol as tracer and gas-liquid chromatography-mass spectrometry techniques for the determination of isotopic enrichment, we have developed a simple and ethically acceptable method of determining glycerol appearance rate in humans under steady-state and nonsteady-state conditions. In normal subjects, the appearance rate of glycerol in the post-absorptive state was 2.22 +/- 0.20 mumol X kg-1 X min-1, a value in agreement with those reported in studies with radioactively labeled tracers. The ratio nonesterified fatty acid (NEFA) appearance rate/glycerol appearance rate ranged from 1.95 to 3.40. In insulin-dependent diabetic patients with a mild degree of metabolic control, the appearance rate of glycerol was 2.48 +/- 0.29 mumol X kg-1 X min-1. The volume of distribution of glycerol, determined by the bolus injection technique, was (mean) 0.306 l X kg-1 in normal subjects and 0.308 l X kg-1 in insulin-independent diabetic patients. To evaluate the usefulness of the method for determination of glycerol kinetics in nonsteady-state conditions, we infused six normal subjects with natural glycerol and calculated the isotopically determined glycerol appearance rate using a single compartment model (volume of distribution 0.31 l X kg-1). During these tests, the expected glycerol appearance rates were successively 5.03 +/- 0.33, 7.48 +/- 0.39, 9.94 +/- 0.34, 7.48 +/- 0.39, and 5.03 +/- 0.33 mumol +/- kg-1 X min-1, whereas the corresponding isotopically determined appearance rates were 4.62 +/- 0.45, 6.95 +/- 0.56, 10.85 +/- 0.51, 7.35 +/- 0.34, and 5.28 +/- 0.12 mumol X kg-1 X min-1

Tracer dating and ocean ventilation

International Nuclear Information System (INIS)

Thiele, G.; Sarmiento, J.L.

1990-01-01

The interpretation of transient tracer observations depends on difficult to obtain information on the evolution in time of the tracer boundary conditions and interior distributions. Recent studies have attempted to circumvent this problem by making use of a derived quantity, age, based on the simultaneous distribution of two complementary tracers, such as tritium and its daughter, helium 3. The age is defined with reference to the surface such that the boundary condition takes on a constant value of zero. The authors use a two-dimensional model to explore the circumstances under which such a combination of conservation equations for two complementary tracers can lead to a cancellation of the time derivative terms. An interesting aspect of this approach is that mixing can serve as a source or sink of tracer based age. The authors define an idealized ventilation age tracer that is conservative with respect to mixing, and they explore how its behavior compares with that of the tracer-based ages over a range of advective and diffusive parameters

Tracers and tracing methods

International Nuclear Information System (INIS)

Leclerc, J.P.

2001-01-01

The first international congress on 'Tracers and tracing methods' took place in Nancy in May 2001. The objective of this second congress was to present the current status and trends on tracing methods and their applications. It has given the opportunity to people from different fields to exchange scientific information and knowledge about tracer methodologies and applications. The target participants were the researchers, engineers and technologists of various industrial and research sectors: chemical engineering, environment, food engineering, bio-engineering, geology, hydrology, civil engineering, iron and steel production... Two sessions have been planned to cover both fundamental and industrial aspects: 1)fundamental development (tomography, tracer camera visualization and particles tracking; validation of computational fluid dynamics simulations by tracer experiments and numerical residence time distribution; new tracers and detectors or improvement and development of existing tracing methods; data treatments and modeling; reactive tracer experiments and interpretation) 2)industrial applications (geology, hydrogeology and oil field applications; civil engineering, mineral engineering and metallurgy applications; chemical engineering; environment; food engineering and bio-engineering). The program included 5 plenary lectures, 23 oral communications and around 50 posters. Only 9 presentations are interested for the INIS database

Tracers and Tracer Testing: Design, Implementation, Tracer Selection, and Interpretation Methods

Energy Technology Data Exchange (ETDEWEB)

G. Michael Shook; Shannon L.; Allan Wylie

2004-01-01

Conducting a successful tracer test requires adhering to a set of steps. The steps include identifying appropriate and achievable test goals, identifying tracers with the appropriate properties, and implementing the test as designed. When these steps are taken correctly, a host of tracer test analysis methods are available to the practitioner. This report discusses the individual steps required for a successful tracer test and presents methods for analysis. The report is an overview of tracer technology; the Suggested Reading section offers references to the specifics of test design and interpretation.

Tracer monitoring of enhanced oil recovery projects

Directory of Open Access Journals (Sweden)

Kleven R.

2013-05-01

Full Text Available In enhanced oil recovery (EOR, chemicals are injected into the oil reservoir, either to increase macroscopic sweep efficiency, or to reduce remaining oil saturation in swept zones. Tracers can be used to identify reservoirs that are specifically suited for EOR operations. Injection of a selection of partitioning tracers, combined with frequent sample analysis of produced fluids, provides information suited for estimation of residual oil saturation. Tracers can also be used to evaluate and optimize the application of EOR chemicals in the reservoir. Suitable tracers will follow the EOR chemicals and assist in evaluation of retention, degradation or trapping. In addition to field applications, tracers also have a large potential as a tool to perform mechanistic studies of EOR chemicals in laboratory experiments. By labelling EOR chemicals with radioactive isotopes of elements such as H, C and S, detailed studies of transport mechanisms can be carried out. Co-injection of labelled compounds in dynamic flooding experiments in porous media will give information about retention or separation of the unique compounds constituting the chemical formulation. Separation of such compounds may be detrimental to obtaining the EOR effect expected. The paper gives new information of specific methods, and discusses current status for use of tracers in EOR operations.

Theoretical analysis of experimental tracer and interdiffusion data in Cu-Ni-Fe alloys

International Nuclear Information System (INIS)

Belova, I.V.; Murch, G.E.; Filipek, R.; Danielewski, M.

2005-01-01

In this paper, we present strategies to extract fundamental atomistic information from measured diffusion coefficients in a ternary alloy system. The strategies are exemplified with Cu-Ni-Fe alloys at 1271 K where recent extensive interdiffusion coefficients and tracer diffusion coefficients for all three components have become available. We develop new defining phenomenological expressions for the vacancy-wind factors in terms of the diffusion coefficients. We show that the measured tracer diffusion coefficients can be processed using the Manning and Moleko, Allnatt and Allnatt random alloy diffusion kinetics formalisms (with and without the assumption of the Gibbs-Duhem relation between the thermodynamic activities) to give jump frequencies, tracer correlation factors, vacancy-wind factors and phenomenological coefficients. It is shown for example that Cu is generally the most correlated component in its diffusion behavior and that the off-diagonal phenomenological coefficients can be as high as 64% of the smallest of the diagonal phenomenological coefficients. It is also shown that the Darken formalism (which ignores off-diagonal phenomenological coefficients) is in fact a reasonable approximation for expressing the diagonal phenomenological coefficients in terms of the tracer diffusion coefficients. It is then shown how the measured interdiffusivities can be processed with these formalisms to give tracer diffusivities, vacancy-wind factors and phenomenological coefficients. Finally, we show how a straightforward strategy starting with the Darken analysis that is then followed by the Manning or Moleko, Allnatt and Allnatt analysis can be used to gain access to the vacancy-wind factors and the off-diagonal phenomenological coefficients

Selection of tracers for oil and gas evaluation

International Nuclear Information System (INIS)

Bjoernstad, T.

1991-08-01

The importance of tracer tests in reservoir descriptions is increasingly acknowledged by reservoir engineers as a method to obtain valuable dynamic information from the reservoir. The report describes the ''state-of-the art'' on tracer technology for interwell investigations. Experiences gained from a number of reported field tracer tests are reviewed, and results from detailed laboratory investigations on the static and dynamic behavior of various tracer molecules are discussed. A critical evaluation of the applicability of the various identified tracers is provided. Present and future trends in the development of tracer technology for reservoir description are sketched. 64 refs., 12 figs., 2 tabs

Use of artificial tracers in hydrology

International Nuclear Information System (INIS)

1991-05-01

The IAEA has convened an Advisory Group Meeting with the following objectives: To define the role of artificial radioactive tracers for water tracing in comparison with other non-radioactive tracers. To evaluate the real needs of artificial radioactive tracers in hydrology. To identify the fields for which artificial radioactive tracers are useful as well as those in which they can be substituted by other tracers. To discuss the strategy to be adopted to overcome the difficulties derived from the restrictions on the use of radioactive tracers in hydrology. The meeting was held at IAEA Headquarters from 19 to 22 March 1990, and was attended by 30 participants from 15 Member States. The conclusions and recommendations are that the use of artificial radioactive tracers should be restricted to cases where other tracers cannot be used or do not provide the same quality of information. Tritium, iodine-131, bromine-82, chromium-51 in the form of Cr-EDTA, technetium-99m obtained from 99 Mo-generators and gold-198 as an adsorbable tracer are, practically, the only radionuclides used for water tracing. The use of other radionuclides for this purpose does not appear to be necessary, possible and/or convenient. Refs, figs and tabs

[18F]Fluoroazabenzoxazoles as potential amyloid plaque PET tracers: synthesis and in vivo evaluation in rhesus monkey

International Nuclear Information System (INIS)

Hostetler, Eric D.; Sanabria-Bohórquez, Sandra; Fan Hong; Zeng, Zhizhen; Gammage, Linda; Miller, Patricia; O'Malley, Stacey; Connolly, Brett; Mulhearn, James; Harrison, Scott T.; Wolkenberg, Scott E.; Barrow, James C.; Williams, David L.; Hargreaves, Richard J.; Sur, Cyrille; Cook, Jacquelynn J.

2011-01-01

Introduction: An 18 F-labeled positron emission tomography (PET) tracer for amyloid plaque is desirable for early diagnosis of Alzheimer's disease, particularly to enable preventative treatment once effective therapeutics are available. Similarly, such a tracer would be useful as a biomarker for enrollment of patients in clinical trials for evaluation of antiamyloid therapeutics. Furthermore, changes in the level of plaque burden as quantified by an amyloid plaque PET tracer may provide valuable insights into the effectiveness of amyloid-targeted therapeutics. This work describes our approach to evaluate and select a candidate PET tracer for in vivo quantification of human amyloid plaque. Methods: Ligands were evaluated for their in vitro binding to human amyloid plaques, lipophilicity and predicted blood–brain barrier permeability. Candidates with favorable in vitro properties were radiolabeled with 18 F and evaluated in vivo. Baseline PET scans in rhesus monkey were conducted to evaluate the regional distribution and kinetics of each tracer using tracer kinetic modeling methods. High binding potential in cerebral white matter and cortical grey matter was considered an unfavorable feature of the candidate tracers. Results: [ 18 F]MK-3328 showed the most favorable combination of low in vivo binding potential in white matter and cortical grey matter in rhesus monkeys, low lipophilicity (Log D=2.91) and high affinity for human amyloid plaques (IC 50 =10.5±1.3 nM). Conclusions: [ 18 F]MK-3328 was identified as a promising PET tracer for in vivo quantification of amyloid plaques, and further evaluation in humans is warranted.

Circulation of the medullary cerebrospinal fluid. Comparative study of various tracers

International Nuclear Information System (INIS)

Bok, B.; Thebault, B.; Cavailloles, F.; Aboulker, J.

Gammamyelography is used to study the circulation of the cerebrospinal fluid in the perimedullary sub-arachoid spaces. Many radioactive preparations have been proposed for this examination which is designed to show up all dynamic perturbations of the CSF flux. Of the criteria governing the choice of tracer some importance given has been to the molecular diffusion constant of the preparation, iodinated albumine seeming the most suitable in this respect. An attempt was made to estimate the influence of molecular weight on the tracer kinetics by comparing three preparations injected simultaneously: indium 111-labelled siderophilline of M.W. above 100,000; iodine 131-labelled human serum albumine of MW around 70,000; sup(99m)Tc-labelled DTPA, a chelate of low molecular weight. The results showed no detectable influence of the molecular weight of these preparations on their intraspinal kinetics in the time taken for the examination. In practice this work justifies the use of the preparation most convenient and least harmful from the dosimetric viewpoint for the isotope and from the antigenic toxicological viewpoint for the tracer, which means that the replacement of iodinated albumine by indium-111 DTPA for example should be possible at least at the medullary level [fr

Quantifying stream nutrient uptake from ambient to saturation with instantaneous tracer additions

Science.gov (United States)

Covino, T. P.; McGlynn, B. L.; McNamara, R.

2009-12-01

Stream nutrient tracer additions and spiraling metrics are frequently used to quantify stream ecosystem behavior. However, standard approaches limit our understanding of aquatic biogeochemistry. Specifically, the relationship between in-stream nutrient concentration and stream nutrient spiraling has not been characterized. The standard constant rate (steady-state) approach to stream spiraling parameter estimation, either through elevating nutrient concentration or adding isotopically labeled tracers (e.g. 15N), provides little information regarding the stream kinetic curve that represents the uptake-concentration relationship analogous to the Michaelis-Menten curve. These standard approaches provide single or a few data points and often focus on estimating ambient uptake under the conditions at the time of the experiment. Here we outline and demonstrate a new method using instantaneous nutrient additions and dynamic analyses of breakthrough curve (BTC) data to characterize the full relationship between spiraling metrics and nutrient concentration. We compare the results from these dynamic analyses to BTC-integrated, and standard steady-state approaches. Our results indicate good agreement between these three approaches but we highlight the advantages of our dynamic method. Specifically, our new dynamic method provides a cost-effective and efficient approach to: 1) characterize full concentration-spiraling metric curves; 2) estimate ambient spiraling metrics; 3) estimate Michaelis-Menten parameters maximum uptake (Umax) and the half-saturation constant (Km) from developed uptake-concentration kinetic curves, and; 4) measure dynamic nutrient spiraling in larger rivers where steady-state approaches are impractical.

Tracers of cancer cells in nuclear oncology

International Nuclear Information System (INIS)

Tamgac, F.; Baillet, G.; Moretti, J.L.; Safi, N.; Weinmann, P.; Beco, V. de

1997-01-01

Evaluating the extent of disease is important in planning cancer treatment. Different types of tracers are used in vivo to diagnose tumors and these tracers can give supplementary information on the differentiation degree of tumors and response to therapy. (authors)

PET and SPET tracers for mapping the cardiac nervous system

International Nuclear Information System (INIS)

Langer, Oliver; Halldin, Christer

2002-01-01

The human cardiac nervous system consists of a sympathetic and a parasympathetic branch with (-)-norepinephrine and acetylcholine as the respective endogenous neurotransmitters. Dysfunction of the cardiac nervous system is implicated in various types of cardiac disease, such as heart failure, myocardial infarction and diabetic autonomic neuropathy. In vivo assessment of the distribution and function of cardiac sympathetic and parasympathetic neurones with positron emission tomography (PET) and single-photon emission tomography (SPET) can be achieved by means of a number of carbon-11-, fluorine-18-, bromine-76- and iodine-123-labelled tracer molecules. Available tracers for mapping sympathetic neurones can be divided into radiolabelled catecholamines, such as 6-[ 18 F]fluorodopamine, (-)-6-[ 18 F]fluoronorepinephrine and (-)-[ 11 C]epinephrine, and radiolabelled catecholamine analogues, such as [ 123 I]meta-iodobenzylguanidine, [ 11 C]meta-hydroxyephedrine, [ 18 F]fluorometaraminol, [ 11 C]phenylephrine and meta-[ 76 Br]bromobenzylguanidine. Resistance to metabolism by monoamine oxidase and catechol-O-methyl transferase simplifies the myocardial kinetics of the second group. Both groups of compounds are excellent agents for an overall assessment of sympathetic innervation. Biomathematical modelling of tracer kinetics is complicated by the complexity of the steps governing neuronal uptake, retention and release of these agents as well as by their high neuronal affinity, which leads to partial flow dependence of uptake. Mapping of cardiac parasympathetic neurones is limited by a low density and focal distribution pattern of these neurones in myocardium. Available tracers are derivatives of vesamicol, a molecule that binds to a receptor associated with the vesicular acetylcholine transporter. Compounds like (-)-[ 18 F]fluoroethoxybenzovesamicol display a high degree of non-specific binding in myocardium which restricts their utility for cardiac neuronal imaging. (orig.)

Study of ketone body kinetics in children by a combined perfusion of 13C and 2H3 tracers

International Nuclear Information System (INIS)

Bougneres, P.F.; Ferre, P.

1987-01-01

Ketone body kinetics were quantified in six children (3-5 yr old), who were fasted for 13-22 h, by a combined perfusion of [3- 13 C]acetoacetate ([ 13 C]AcAc) and D-(-)-beta-[4,4,4- 2 H3]hydroxybutyrate (beta-[ 2 H3]OHB) and gas chromatography-mass spectrometry analysis. Results were analyzed according to the single-pool (combined enrichments) or the two-accessible pools models. After 20-22 h of fasting, ketone body turnover rate was 30-50 mumol.kg-1.min-1, a rate achieved after several days of fasting in adults. At low ketosis, acetoacetate was the ketone body preferentially synthesized de novo and utilized irreversibly. When ketosis increased, acetoacetate irreversible disposal was not enhanced, since it was largely converted into beta-OHB, whereas beta-OHB irreversible disposal was very much increased. The single-pool and two-pool models gave similar ketone body turnover rates when [ 13 C]AcAc was the tracer, whereas the use of beta-[ 2 H3]OHB gave some more divergent results, especially at low ketosis. These studies demonstrate that ketogenesis is very active in short-term fasted children and that the use of a combined infusion of [ 13 C]AcAc and beta-[ 2 H3]OHB is a convenient way to give insight into individual ketone body kinetics

Journal: Efficient Hydrologic Tracer-Test Design for Tracer ...

Science.gov (United States)

Hydrological tracer testing is the most reliable diagnostic technique available for the determination of basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed to facilitate the design of tracer tests by root determination of the one-dimensional advection-dispersion equation (ADE) using a preset average tracer concentration which provides a theoretical basis for an estimate of necessary tracer mass. The method uses basic measured field parameters (e.g., discharge, distance, cross-sectional area) that are combined in functional relatipnships that descrive solute-transport processes related to flow velocity and time of travel. These initial estimates for time of travel and velocity are then applied to a hypothetical continuous stirred tank reactor (CSTR) as an analog for the hydrological-flow system to develop initial estimates for tracer concentration, tracer mass, and axial dispersion. Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to be necessary for descri

Asian Tracer Experiment and Atmospheric Modeling (TEAM) Project: Draft Field Work Plan for the Asian Long-Range Tracer Experiment

Energy Technology Data Exchange (ETDEWEB)

Allwine, K Jerry; Flaherty, Julia E.

2007-08-01

This report provides an experimental plan for a proposed Asian long-range tracer study as part of the international Tracer Experiment and Atmospheric Modeling (TEAM) Project. The TEAM partners are China, Japan, South Korea and the United States. Optimal times of year to conduct the study, meteorological measurements needed, proposed tracer release locations, proposed tracer sampling locations and the proposed durations of tracer releases and subsequent sampling are given. Also given are the activities necessary to prepare for the study and the schedule for completing the preparation activities leading to conducting the actual field operations. This report is intended to provide the TEAM members with the information necessary for planning and conducting the Asian long-range tracer study. The experimental plan is proposed, at this time, to describe the efforts necessary to conduct the Asian long-range tracer study, and the plan will undoubtedly be revised and refined as the planning goes forward over the next year.

Glucose tracer, kinetics and turnover in monkeys and chickens infused with ethanol, 1,3-butanediol, or fructose

International Nuclear Information System (INIS)

Armstrong, M.K.

1985-01-01

Mixtures of (2- 3 H) and (U- 14 C) glucose were injected as single doses into fasted cynomolgus monkeys to assess glucose tracer kinetics and obtain rates of turnover. Data were treated by stochastic and compartmental analyses and results from both analyses closely agreed. However, (2- 3 H) data analyzed by the compartmental analysis required three pools to fit the glucose disappearance curve while (6- 3 H) data fit a two or three pool model equally well. Turnover rates averaged 4.9-4.0, and 3.0 mg/min x kg -1 body weight with (2- 3 H), 6- 3 H) and (U- 14 C) glucose tracers, respectively. The data heuristically suggest that the slow turnover pool that was necessary to fit (2- 3 H) glucose data is related to isotope discrimination. The effects of four treatment solutions on (6- 3 H) glucose metabolism in monkeys were examined. The solutions and their rates of infusion (umoles/min x kg -1 ) were: (1) ethanol, 110; (2) 1,3-butanediol, 110; (3) fructose, 30; and (4) ethanol pus fructose, 110 and 30, respectively. The glucose clearance rate was lowest during the ethanol plus fructose infusions. Ethanol infusions (222 or 444 umoles/min x kg -1 body weight) in chickens (1500 g) fasted 64 hours did not cause hypoglycemia although the high dose slightly decreased the rate of glucose turnover 15% (14.0 versus 12.0 mg/min x kg -1 ). It was further found that neither the hepatic cytosolic nor the mitochondrial redox state significantly changed in chickens infused with the high dose of ethanol. The unchanged hepatic metabolite ratios in chickens are consistent with their unusual resistance to ethanol-induced hypoglycemia

Reassessment of primed constant-infusion tracer method to measure urea kinetics

International Nuclear Information System (INIS)

Jahoor, F.; Wolfe, R.R.

1987-01-01

The validity of the primed constant-infusion tracer technique to make short-term measurements of urea production rates (R/sub a/) in humans in a physiological steady state and during disruption of steady state was evaluated. Four subjects received a primed constant infusion (P/I = 560 min) of [ 13 C]urea for 8 h. A plateau in urea enrichment was reached after 2 h and maintained throughout. When [ 13 C]- and [ 18 O]urea were simultaneously infused into four subjects at P/I ratios of 560:1 and 360:1, respectively, both tracers reached plateau enrichment at the same time (2-4 h). The enrichment at plateau was a function of the infusion rate rather than the priming dose, and calculated urea R/sub a/ was the same with either prime. In five additional experiments the technique responded acutely to a physiological perturbation (alanine infusion) in a dose-dependent manner. The results confirm that this technique is appropriate for short-term measurements of urea R/sub a/, and the requirement for accuracy in estimating the priming dose is not impractically stringent

Tumoral tracers

International Nuclear Information System (INIS)

Camargo, E.E.

1979-01-01

Direct tumor tracers are subdivided in the following categories:metabolite tracers, antitumoral tracers, radioactive proteins and cations. Use of 67 Ga-citrate as a clinically important tumoral tracer is emphasized and gallium-67 whole-body scintigraphy is discussed in detail. (M.A.) [pt

Principles and techniques of gamma ray tracers

International Nuclear Information System (INIS)

Claxton, K.T.

1978-01-01

Radioactive tracer techniques provide a very sensitive means of studying physical and chemical processes in a whole variety of different media. Some of the techniques and principles of radioactive tracers and their application to practical engineering systems are discussed. Information which has been found useful in the design of high temperature liquid sodium facilities employing radio-tracers, is presented. The report deals solely with the use of gamma-emitting species as the tracer. These find particular application for in-situ studies on engineering systems where the highly penetrating properties of gamma rays are needed for detection through strongly absorbent media such as stainless steel pepe walls. (author)

TracerLPM (Version 1): An Excel® workbook for interpreting groundwater age distributions from environmental tracer data

Science.gov (United States)

Jurgens, Bryant C.; Böhlke, J.K.; Eberts, Sandra M.

2012-01-01

point in time; however, prior knowledge of an appropriate LPM is required because the mean age is often non-unique. LPM output concentrations depend on model parameters and sample date. All of the LPMs have a parameter for mean age. The EPM, PEM, and DM have an additional parameter that characterizes the degree of age mixing in the sample. BMMs have a parameter for the fraction of the first component in the mixture. An LPM, together with its parameter values, provides a description of the age distribution or the fractional contribution of water for every age of recharge contained within a sample. For the PFM, the age distribution is a unit pulse at one distinct age. For the other LPMs, the age distribution can be much broader and span decades, centuries, millennia, or more. For a sample with a mixture of groundwater ages, the reported interpretation of tracer data includes the LPM name, the mean age, and the values of any other independent model parameters. TracerLPM also can be used for simulating the responses of wells, springs, streams, or other groundwater discharge receptors to nonpoint-source contaminants that are introduced in recharge, such as nitrate. This is done by combining an LPM or user-defined age distribution with information on contaminant loading at the water table. Information on historic contaminant loading can be used to help evaluate a model's ability to match real world conditions and understand observed contaminant trends, while information on future contaminant loading scenarios can be used to forecast potential contaminant trends.

Compartmental Modeling and Dosimetry of in Vivo Metabolic Studies of Leucine and Three Secretory Proteins in Humans Using Radioactive Tracers

Science.gov (United States)

Venkatakrishnan, Vaidehi

1995-01-01

Physical and mathematical models provide a systematic means of looking at biological systems. Radioactive tracer kinetic studies open a unique window to study complex tracee systems such as protein metabolism in humans. This research deals with compartmental modeling of tracer kinetic data on leucine and apolipoprotein metabolism obtained using an endogenous tritiated leucine tracer administered as a bolus, and application of compartmental modeling techniques for dosimetric evaluation of metabolic studies of radioiodinated apolipoproteins. Dr. Waldo R. Fisher, Department of Medicine, was the coordinating research supervisor and the work was carried out in his laboratory. A compartmental model for leucine kinetics in humans has been developed that emphasizes its recycling pathways which were examined over two weeks. This model builds on a previously published model of Cobelli et al, that analyzed leucine kinetic data up to only eight hours. The proposed model includes different routes for re-entry of leucine from protein breakdown into plasma accounting for proteins which turn over at different rates. This new model successfully incorporates published models of three secretory proteins: albumin, apoA-I, and VLDL apoB, in toto thus increasing its validity and utility. The published model of apoA-I, based on an exogenous radioiodinated tracer, was examined with data obtained using an endogenous leucine tracer using compartmental techniques. The analysis concludes that the major portion of apoA-I enters plasma by a fast pathway but the major fraction of apoA-I in plasma resides with a second slow pathway; further the study is suggestive of a precursor-product relationship between the two plasma apoA-I pools. The possible relevance of the latter suggestion to the aberrant kinetics of apoA-I in Tangier disease is discussed. The analysis of apoA-II data resulted in similar conclusions. A methodology for evaluating the dosimetry of radioiodinated apolipoproteins by

Design and utilisation of protocols to characterise dynamic PET uptake of two tracers using basis pursuit

Science.gov (United States)

Bell, Christopher; Puttick, Simon; Rose, Stephen; Smith, Jye; Thomas, Paul; Dowson, Nicholas

2017-06-01

Imaging using more than one biological process using PET could be of great utility, but despite previously proposed approaches to dual-tracer imaging, it is seldom performed. The alternative of performing multiple scans is often infeasible for clinical practice or even in research studies. Dual-tracer PET scanning allows for multiple PET radiotracers to be imaged within the same imaging session. In this paper we describe our approach to utilise the basis pursuit method to aid in the design of dual-tracer PET imaging experiments, and later in separation of the signals. The advantage of this approach is that it does not require a compartment model architecture to be specified or even that both signals are distinguishable in all cases. This means the method for separating dual-tracer signals can be used for many feasible and useful combinations of biology or radiotracer, once an appropriate scanning protocol has been decided upon. Following a demonstration in separating the signals from two consecutively injected radionuclides in a controlled experiment, phantom and list-mode mouse experiments demonstrated the ability to test the feasibility of dual-tracer imaging protocols for multiple injection delays. Increases in variances predicted for kinetic macro-parameters V D and K I in brain and tumoral tissue were obtained when separating the synthetically combined data. These experiments confirmed previous work using other approaches that injections delays of 10-20 min ensured increases in variance were kept minimal for the test tracers used. On this basis, an actual dual-tracer experiment using a 20 min delay was performed using these radio tracers, with the kinetic parameters (V D and K I) extracted for each tracer in agreement with the literature. This study supports previous work that dual-tracer PET imaging can be accomplished provided certain constraints are adhered to. The utilisation of basis pursuit techniques, with its removed need to specify a model

Simplification of complex kinetic models used for the quantitative analysis of nuclear magnetic resonance or radioactive tracer studies

International Nuclear Information System (INIS)

Schuster, R.; Schuster, S.; Holzhuetter, H.-G.

1992-01-01

A method for simplifying the mathematical models describing the dynamics of tracers (e.g. 13 C, 31 P, 14 C, as used in NMR studies or radioactive tracer experiments) in (bio-)chemical reaction systems is presented. This method is appropriate in the cases where the system includes reactions, the rates of which differ by several orders of magnitude. The basic idea is to adapt the rapid-equilibrium approximation to tracer systems. It is shown with the aid of the Perron-Frobenius theorem that for tracer systems, the conditions for applicability of this approximation are satisfied whenever some reactions are near equilibrium. It turns out that the specific enrichments of all of the labelled atoms that are connected by fast reversible reactions can be grouped together as 'pool variables'. The reduced system contains fewer parameters and can, thus, be fitted more easily to experimental data. Moreover, the method can be employed for identifying non-equilibrium and near-equilibrium reactions from experimentally measured specific enrichments of tracer. The reduction algorithm is illustrated by studying a model of the distribution of 13 C-tracers in the pentose phosphate pathway. (author)

Characterization of reactive tracers for C-wells field experiments 1: Electrostatic sorption mechanism, lithium

International Nuclear Information System (INIS)

Fuentes, H.R.; Polzer, W.L.; Essington, E.H.; Newman, B.D.

1989-11-01

Lithium (Li + ) was introduced as lithium bromide (LiBr), as a retarded tracer for experiments in the C-wells complex at Yucca Mountain, Nevada Test Site, Nevada. The objective was to evaluate the potential of lithium to sorb predominately by physical forces. lithium was selected as a candidate tracer on the basis of high solubility, good chemical and biological stability, and relatively low sorptivity; lack of bioaccumulation and exclusion as a priority pollutant in pertinent federal environmental regulations; good analytical detectability and low natural background concentrations; and a low cost Laboratory experiments were performed with suspensions of Prow Pass cuttings from drill hole UE-25p number-sign 1 at depths between 549 and 594 m in J-13 water at a pH of approximately 8 and in the temperature range of 25 degree C to 45 degree C. Batch equilibrium and kinetics experiments were performed; estimated thermodynamic constants, relative behavior between adsorption and desorption, and potentiometric studies provided information to infer the physical nature of lithium sorption

Tracer-tracer relations as a tool for research on polar ozone loss

Energy Technology Data Exchange (ETDEWEB)

Mueller, Rolf

2010-07-01

The report includes the following chapters: (1) Introduction: ozone in the atmosphere, anthropogenic influence on the ozone layer, polar stratospheric ozone loss; (2) Tracer-tracer relations in the stratosphere: tracer-tracer relations as a tool in atmospheric research; impact of cosmic-ray-induced heterogeneous chemistry on polar ozone; (3) quantifying polar ozone loss from ozone-tracer relations: principles of tracer-tracer correlation techniques; reference ozone-tracer relations in the early polar vortex; impact of mixing on ozone-tracer relations in the polar vortex; impact of mesospheric intrusions on ozone-tracer relations in the stratospheric polar vortex calculation of chemical ozone loss in the arctic in March 2003 based on ILAS-II measurements; (4) epilogue.

Radiochemical tracers in marine biology

International Nuclear Information System (INIS)

Petrocelli, S.R.; Anderson, J.W.; Neff, J.M.

1977-01-01

Tracers have been used in a great variety of experimentation. More recently, labeled materials have been applied in marine biological research. Some of the existing tracer techniques have been utilized directly, while others have been modified to suit the specific needs of marine biologists. This chapter describes some of the uses of tracers in marine biological research. It also mentions the problems encountered as well as offering possible solutions and discusses further applications of these techniques. Only pertinent references are cited and additional information may be obtained by consulting these references. Due to their relative ease of maintenance, freshwater species are also utilized in studies which involve radiotracer techniques. Since most of these techniques e directly applicable to marine species, some of these studies will also be included

(18)F-FDG dynamic PET/CT in patients with multiple myeloma: patterns of tracer uptake and correlation with bone marrow plasma cell infiltration rate.

Science.gov (United States)

Sachpekidis, Christos; Mai, Elias K; Goldschmidt, Hartmut; Hillengass, Jens; Hose, Dirk; Pan, Leyun; Haberkorn, Uwe; Dimitrakopoulou-Strauss, Antonia

2015-06-01

The value of F-FDG PET in the diagnostic approach of multiple myeloma (MM) remains incompletely elicited. Little is known about the kinetics of F-FDG in the bone marrow and extramedullary sites in MM. This study aimed to evaluate quantitative data on kinetics and distribution patterns of F-FDG in MM patients with regard to pelvic bone marrow plasma cell infiltration. The study included 40 patients with primary MM. Dynamic PET/CT scanning of the lower lumbar spine and pelvis was performed after the administration of F-FDG. Whole-body PET/CT studies were performed. Sites of focal increased tracer uptake were considered as highly suggestive of myelomatous involvement after taking into account the patient history and CT findings. Bone marrow of the os ilium without pathologic tracer accumulation served as reference. The evaluation of dynamic PET/CT studies was based in addition to the conventional visual (qualitative) assessment, on semiquantitative (SUV) calculations, as well as on absolute quantitative estimations after application of a 2-tissue compartment model and a noncompartmental approach. F-FDG quantitative information and corresponding distribution patterns were correlated with pelvic bone marrow plasma cell infiltration. Fifty-two myelomatous lesions were detected in the pelvis. All parameters in suspected MM lesions ranged in significantly higher levels than in reference tissue (P PET/CT imaging demonstrated 4 patterns of tracer uptake; these are as follows: negative, focal, diffuse, and mixed (focal/diffuse) tracer uptake. Patients with a mixed pattern of radiotracer uptake had the highest mean plasma cell infiltration rate in their bone marrow, whereas those with negative PET/CT scans demonstrated the lowest bone marrow plasma cell infiltration. In total, 265 focal myeloma-indicative F-FDG-avid lesions were detected, 129 of which correlated with low-dose CT osteolytic findings. No significant correlation between the number of focal lesions detected in PET

Oxfold: Kinetic Folding of RNA using Stochastic Context-Free Grammars and Evolutionary Information

DEFF Research Database (Denmark)

Anderson, James W.J.; Haas, Pierre A.; Mathieson, Leigh-Anne

2013-01-01

Motivation: Many computational methods for RNA secondary structure prediction, and, in particular, for the prediction of a consensus structure of an alignment of RNA sequences, have been developed. Most methods however ignore biophysical factors such as the kinetics of RNA folding; no current...... implementation considers both evolutionary information and folding kinetics, thus losing information which, when considered, might lead to better predictions. Results: We present an iterative algorithm, Oxfold, in the framework of stochastic context-free grammars, that emulates the kinetics of RNA folding...

Radionuclides as tracers

International Nuclear Information System (INIS)

Ganatra, R.D.

1992-01-01

Importance of radioisotopes in medicine is because of their two characteristics: their biological behaviour is identical to their stable counterparts, and because they are radioactive their emissions can be detected by a suitable instrument. All isotopes of iodine will behave in the same way and will concentrate in the thyroid gland. There is no way of detecting the stable, natural iodine in the thyroid gland, but the presence of radioactive iodine can be detected externally in vivo by a detector. Thus, the radioactive iodine becomes a tracer, a sport of a spy, which mimics the behaviour of natural iodine and relays information to a detector. The radioactive tracers are popular because of the ease with which they can be detected in vivo and the fact that the measurement of their presence in the body can be in quantitative terms. The measurement can be very accurate and sensitive. Whenever the measurements can be done in vivo, the information is obtained in dynamic terms, as it is happening, as if the physiological events become transparent

Study of ketone body kinetics in children by a combined perfusion of /sup 13/C and /sup 2/H3 tracers

Energy Technology Data Exchange (ETDEWEB)

Bougneres, P.F.; Ferre, P.

1987-11-01

Ketone body kinetics were quantified in six children (3-5 yr old), who were fasted for 13-22 h, by a combined perfusion of (3-/sup 13/C)acetoacetate ((/sup 13/C)AcAc) and D-(-)-beta-(4,4,4-/sup 2/H3)hydroxybutyrate (beta-(/sup 2/H3)OHB) and gas chromatography-mass spectrometry analysis. Results were analyzed according to the single-pool (combined enrichments) or the two-accessible pools models. After 20-22 h of fasting, ketone body turnover rate was 30-50 mumol.kg-1.min-1, a rate achieved after several days of fasting in adults. At low ketosis, acetoacetate was the ketone body preferentially synthesized de novo and utilized irreversibly. When ketosis increased, acetoacetate irreversible disposal was not enhanced, since it was largely converted into beta-OHB, whereas beta-OHB irreversible disposal was very much increased. The single-pool and two-pool models gave similar ketone body turnover rates when (/sup 13/C)AcAc was the tracer, whereas the use of beta-(/sup 2/H3)OHB gave some more divergent results, especially at low ketosis. These studies demonstrate that ketogenesis is very active in short-term fasted children and that the use of a combined infusion of (/sup 13/C)AcAc and beta-(/sup 2/H3)OHB is a convenient way to give insight into individual ketone body kinetics.

Kinetic and Related Determinants of Plasma Triglyceride Concentration in Abdominal Obesity: Multicenter Tracer Kinetic Study.

Science.gov (United States)

Borén, Jan; Watts, Gerald F; Adiels, Martin; Söderlund, Sanni; Chan, Dick C; Hakkarainen, Antti; Lundbom, Nina; Matikainen, Niina; Kahri, Juhani; Vergès, Bruno; Barrett, P Hugh R; Taskinen, Marja-Riitta

2015-10-01

Patients with obesity and diabetes mellitus have increased risk of cardiovascular disease. A major cause is an atherogenic dyslipidemia related primarily to elevated plasma concentrations of triglyceride-rich lipoproteins. The aim of this study was to clarify determinants of plasma triglyceride concentration. We focused on factors that predict the kinetics of very-low density lipoprotein 1 (VLDL1) triglycerides. A multicenter study using dual stable isotopes (deuterated leucine and glycerol) and multicompartmental modeling was performed to elucidate the kinetics of triglycerides and apoB in VLDL1 in 46 subjects with abdominal obesity and additional cardiometabolic risk factors. Results showed that plasma triglyceride concentrations were dependent on both the secretion rate (r=0.44, Ptriglycerides and VLDL1-apoB. Liver fat mass was independently and directly associated with secretion rates of VLDL1-triglycerides (r=0.56, Ptriglycerides (r=0.48, Ptriglyceride concentrations in abdominal obesity are determined by the kinetics of VLDL1 subspecies, catabolism being mainly dependent on apoC-III concentration and secretion on liver fat content. Reduction in liver fat and targeting apoC-III may be an effective approach for correcting triglyceride metabolism atherogenic dyslipidemia in obesity. © 2015 American Heart Association, Inc.

The kinetics of multi-compartmentalized systems, studied by radioactive tracers

International Nuclear Information System (INIS)

Gouveia, A.S. de.

1978-01-01

The use of compartmental models to investigate kinetic problems is presented. This use is restricted, however, to linear models. As an application of different methods, the kinetic behaviour of haemaccel labelled with iodine 131 is studied, the interval of the physically viable solutions being established. The existence of a class of solutions is explained as a result of lack of knowledge of a complete data set. The possibility of obtaining a single solution is also discussed. The formalism of the program SAAM (Simulation, Analysis and modelling) now judged very important for the study of multi-compartimental analysis is presented. (I.C.R) [pt

Using tracers to understand the hydrology of an abandoned underground coal mine

International Nuclear Information System (INIS)

Canty, G.A.; Everett, J.W.

1998-01-01

Flooded underground mines pose a difficult problem for remediation efforts requiring hydrologic information. Mine environments are hydraulically complicated due to sinuous travel paths and variable hydraulic gradients. For an acidic mine remediation project, conducted by the University of Oklahoma in conjunction with the Oklahoma Conservation Commission, a tracer study was undertaken to identify basic hydrologic properties of a flooded coal mine. The study was conducted to investigate the possibility of in-situ remediation of acidic mine water with the use of alkaline coal combustion by-products. Information on the rate of flow and ''connectiveness'' of injection wells with the discharge point was needed to develop a treatment strategy. Fluorescent dyes are not typically used in mine tracer studies because of the low pH values associated with certain mines and a tendency to adsorb ferric iron precipitates. However, Rhodamine WT was used in one tracer test because it can be detected at low concentrations. Due to poor recovery, a second tracer test was undertaken using a more conservative tracer-chloride. Each tracer produced similar travel time results. Findings from this study suggest that Rhodamine WT can be used under slightly acidic conditions, with mixed results. The more conservative tracer provided somewhat better results, but recovery was still poor. Use of these tracers has provided some valuable information with regard to mine hydrology, but additional questions have been raised

Positron emitting tracers for studies of cocaine

International Nuclear Information System (INIS)

Fowler, J.S.; Gatley, S.J.; MacGregor, R.R.; Wolf, A.P.; Yu, D.W.; Dewey, S.L.; Schlyer, D.J.; Volkow, N.D.; Bendriem, B.; Logan, J.

1990-01-01

The use of PET to study the behavior and mechanism of action of therapeutic drugs and substances of abuse can be approached from a number of perspectives. The most common approach is to measure the effect of a drug on some aspect of metabolism and requires well characterized radiotracers whose behavior in vivo can be related to a discrete biochemical transformation. A second approach is to study the labeled drug itself. This provides information on the drug's regional distribution and kinetics as well as its pharmacological profile and metabolism. Cocaine has been labeled in different positions with carbon-11 and with fluorine-18 and the stereoisomers of cocaine have also been labeled to characterize its binding and metabolism in human and baboon brain. Regional cocaine binding as measured by PET is consistent with reversible binding to striatal dopamine reuptake sites and its time course parallels the behavioral activation of cocaine. The behaviorally inactive enantiomer (+)-cocaine is rapidly metabolized in serum preventing its entry into the brain. These PET tracers are useful in understanding the neurochemical basis of cocaine's action

Determining Near-Bottom Fluxes of Passive Tracers in Aquatic Environments

Science.gov (United States)

Bluteau, Cynthia E.; Ivey, Gregory N.; Donis, Daphne; McGinnis, Daniel F.

2018-03-01

In aquatic systems, the eddy correlation method (ECM) provides vertical flux measurements near the sediment-water interface. The ECM independently measures the turbulent vertical velocities w' and the turbulent tracer concentration c' at a high sampling rate (> 1 Hz) to obtain the vertical flux w'c'¯ from their time-averaged covariance. This method requires identifying and resolving all the flow-dependent time (and length) scales contributing to w'c'¯. With increasingly energetic flows, we demonstrate that the ECM's current technology precludes resolving the smallest flux-contributing scales. To avoid these difficulties, we show that for passive tracers such as dissolved oxygen, w'c'¯ can be measured from estimates of two scalar quantities: the rate of turbulent kinetic energy dissipation ɛ and the rate of tracer variance dissipation χc. Applying this approach to both laboratory and field observations demonstrates that w'c'¯ is well resolved by the new method and can provide flux estimates in more energetic flows where the ECM cannot be used.

Biological tracer for waste site characterization

International Nuclear Information System (INIS)

Strong-Gunderson, J.

1995-01-01

Remediating hazardous waste sites requires detailed site characterization. In groundwater remediation, characterizing the flow paths and velocity is a major objective. Various tracers have been used for measuring groundwater velocity and transport of contaminants, colloidal particles, and bacteria and nutrients. The conventional techniques use dissolved solutes, dyes. and gases to estimate subsurface transport pathways. These tracers can provide information on transport and diffusion into the matrix, but their estimates for groundwater flow through fractured regions are very conservative. Also, they do not have the same transport characteristics as bacteria and suspended colloid tracers, both of which must be characterized for effective in-place remediation. Bioremediation requires understanding bacterial transport and nutrient distribution throughout the acquifer, knowledge of contaminants s mobile colloidal particles is just essential

Hybrid tracers for sentinel node biopsy

International Nuclear Information System (INIS)

Van Den Berg, N. S.; Kleinjan, G. I.; Valdés-Olmos, R. A.; Buckle, T.; Van Leeuwen, F. I.; Klop, W. M.; Horenblas, S.; Van Der Poel, H. G.

2014-01-01

Conventional sentinel node (SN) mapping is performed by injection of a radiocolloid followed by lymphoscintigraphy to identify the number and location of the primary tumor draining lymph node(s), the so-called SN(s). Over the last decade research has focused on the introduction of new imaging agents that can further aid (surgical) SN identification. Different tracers for SN mapping, with varying sizes and isotopes have been reported, most of which have proven their value in a clinical setting. A major challenge lies in transferring this diagnostic information obtained at the nuclear medicine department to the operating theatre thereby providing the surgeon with (image) guidance. Conventionally, an intraoperative injection of vital blue dye or a fluorescence dye is given to allow intraoperative optical SN identification. However, for some indications, the radiotracer-based approach remains crucial. More recently, hybrid tracers, that contain both a radioactive and fluorescent label, were introduced to allow for direct integration of pre- and intraoperative guidance technologies. Their potential is especially high when they are used in combination with new surgical imaging modalities and navigation tools. Next to a description of the known tracers for SN mapping, this review discusses the application of hybrid tracers during SN biopsy and how the introduction of these new techniques can further aid in translation of nuclear medicine information into the operating theatre.

In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests

International Nuclear Information System (INIS)

Smith, R.L.; Howes, B.L.; Garabedian, S.P.

1991-01-01

Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate was prepared with groundwater from the tracer site to maintain the same geochemical conditions. Methane oxidation was calculated from breakthrough curves of methane relative to halide and inert gas (hexafluoroethane) tracers and was confirmed by the appearance of 13 C-enriched carbon dioxide in experiments in which 13 C-enriched methane was used as the tracer. A V max for methane oxidation could be calculated when the methane concentration was sufficiently high to result in zero-order kinetics throughout the entire transport interval. Methane breakthrough curves could be simulated by modifying a one-dimensional advection-dispersion transport model to include a Michaelis-Menten-based consumption term for methane oxidation. The K m values for methane oxidation that gave the best match for the breakthrough curve peaks were 6.0 and 9.0 μM for the uncontaminated and contaminated sites, respectively. Natural-gradient tracer tests are a promising approach for assessing microbial processes and for testing in situ bioremediation potential in groundwater systems

(18)F-alfatide II and (18)F-FDG dual-tracer dynamic PET for parametric, early prediction of tumor response to therapy.

Science.gov (United States)

Guo, Jinxia; Guo, Ning; Lang, Lixin; Kiesewetter, Dale O; Xie, Qingguo; Li, Quanzheng; Eden, Henry S; Niu, Gang; Chen, Xiaoyuan

2014-01-01

A single dynamic PET acquisition using multiple tracers administered closely in time could provide valuable complementary information about a tumor's status under quasiconstant conditions. This study aimed to investigate the utility of dual-tracer dynamic PET imaging with (18)F-alfatide II ((18)F-AlF-NOTA-E[PEG4-c(RGDfk)]2) and (18)F-FDG for parametric monitoring of tumor responses to therapy. We administered doxorubicin to one group of athymic nude mice with U87MG tumors and paclitaxel protein-bound particles to another group of mice with MDA-MB-435 tumors. To monitor therapeutic responses, we performed dual-tracer dynamic imaging, in sessions that lasted 90 min, starting with injection via the tail vein catheters with (18)F-alfatide II, followed 40 min later by (18)F-FDG. To achieve signal separation of the 2 tracers, we fit a 3-compartment reversible model to the time-activity curve of (18)F-alfatide II for the 40 min before (18)F-FDG injection and then extrapolated to 90 min. The (18)F-FDG tumor time-activity curve was isolated from the 90-min dual-tracer tumor time-activity curve by subtracting the fitted (18)F-alfatide II tumor time-activity curve. With separated tumor time-activity curves, the (18)F-alfatide II binding potential (Bp = k3/k4) and volume of distribution (VD) and (18)F-FDG influx rate ((K1 × k3)/(k2 + k3)) based on the Patlak method were calculated to validate the signal recovery in a comparison with 60-min single-tracer imaging and to monitor therapeutic response. The transport and binding rate parameters K1-k3 of (18)F-alfatide II, calculated from the first 40 min of the dual-tracer dynamic scan, as well as Bp and VD correlated well with the parameters from the 60-min single-tracer scan (R(2) > 0.95). Compared with the results of single-tracer PET imaging, (18)F-FDG tumor uptake and influx were recovered well from dual-tracer imaging. On doxorubicin treatment, whereas no significant changes in static tracer uptake values of (18)F-alfatide II

Spectroscopic diagnostics for ablation cloud of tracer-encapsulated solid pellet in LHD

International Nuclear Information System (INIS)

Tamura, N.; Kalinina, D. V.; Sato, K.; Sudo, S.; Sergeev, V. Yu.; Miroshnikov, I. V.; Sharov, I. A.; Bakhareva, O. A.; Ivanova, D. M.; Timokhin, V. M.; Kuteev, B. V.

2008-01-01

In the Large Helical Device (LHD), various spectroscopic diagnostics have been applied to study the ablation process of an advanced impurity pellet, tracer-encapsulated solid pellet (TESPEL). The total light emission from the ablation cloud of TESPEL is measured by photomultipliers equipped with individual interference filters, which provide information about the TESPEL penetration depth. The spectra emitted from the TESPEL ablation cloud are measured with a 250 mm Czerny-Turner spectrometer equipped with an intensified charge coupled device detector, which is operated in the fast kinetic mode. This diagnostic allows us to evaluate the temporal evolution of the electron density in the TESPEL ablation cloud. In order to gain information about the spatial distribution of the cloud parameters, a nine image optical system that can simultaneously acquire nine images of the TESPEL ablation cloud has recently been developed. Several images of the TESPEL ablation cloud in different spectral domains will give us the spatial distribution of the TESPEL cloud density and temperature.

Tracer theory

International Nuclear Information System (INIS)

Margrita, R.

1988-09-01

Tracers are used in many fields of science to investigate mass transfer. The scope of tracers applications in Service of Applications Radioisotopes (S.A.R.-France) is large and concerns natural and industrial systems such as Sciences of earth: hydrology - civil engineering - Sedimentology - environmental studies. Industrial field: chemical engineering - mechanical engineering. A general tracer methodology has been developed in our laboratories from these different applications fields and this paper shows these different points of view in using tracers; our wish is that the methods used in an experimental field can be employed in an another one

A robust state-space kinetics-guided framework for dynamic PET image reconstruction

International Nuclear Information System (INIS)

Tong, S; Alessio, A M; Kinahan, P E; Liu, H; Shi, P

2011-01-01

Dynamic PET image reconstruction is a challenging issue due to the low SNR and the large quantity of spatio-temporal data. We propose a robust state-space image reconstruction (SSIR) framework for activity reconstruction in dynamic PET. Unlike statistically-based frame-by-frame methods, tracer kinetic modeling is incorporated to provide physiological guidance for the reconstruction, harnessing the temporal information of the dynamic data. Dynamic reconstruction is formulated in a state-space representation, where a compartmental model describes the kinetic processes in a continuous-time system equation, and the imaging data are expressed in a discrete measurement equation. Tracer activity concentrations are treated as the state variables, and are estimated from the dynamic data. Sampled-data H ∞ filtering is adopted for robust estimation. H ∞ filtering makes no assumptions on the system and measurement statistics, and guarantees bounded estimation error for finite-energy disturbances, leading to robust performance for dynamic data with low SNR and/or errors. This alternative reconstruction approach could help us to deal with unpredictable situations in imaging (e.g. data corruption from failed detector blocks) or inaccurate noise models. Experiments on synthetic phantom and patient PET data are performed to demonstrate feasibility of the SSIR framework, and to explore its potential advantages over frame-by-frame statistical reconstruction approaches.

Improving Marine Ecosystem Models with Biochemical Tracers

Science.gov (United States)

Pethybridge, Heidi R.; Choy, C. Anela; Polovina, Jeffrey J.; Fulton, Elizabeth A.

2018-01-01

Empirical data on food web dynamics and predator-prey interactions underpin ecosystem models, which are increasingly used to support strategic management of marine resources. These data have traditionally derived from stomach content analysis, but new and complementary forms of ecological data are increasingly available from biochemical tracer techniques. Extensive opportunities exist to improve the empirical robustness of ecosystem models through the incorporation of biochemical tracer data and derived indices, an area that is rapidly expanding because of advances in analytical developments and sophisticated statistical techniques. Here, we explore the trophic information required by ecosystem model frameworks (species, individual, and size based) and match them to the most commonly used biochemical tracers (bulk tissue and compound-specific stable isotopes, fatty acids, and trace elements). Key quantitative parameters derived from biochemical tracers include estimates of diet composition, niche width, and trophic position. Biochemical tracers also provide powerful insight into the spatial and temporal variability of food web structure and the characterization of dominant basal and microbial food web groups. A major challenge in incorporating biochemical tracer data into ecosystem models is scale and data type mismatches, which can be overcome with greater knowledge exchange and numerical approaches that transform, integrate, and visualize data.

Compilation and analyses of results from cross-hole tracer tests with conservative tracers

Energy Technology Data Exchange (ETDEWEB)

Hjerne, Calle; Nordqvist, Rune; Harrstroem, Johan (Geosigma AB (Sweden))

2010-09-15

Radionuclide transport in hydrogeological formations is one of the key factors for the safety analysis of a future repository of nuclear waste. Tracer tests have therefore been an important field method within the SKB investigation programmes at several sites since the late 1970's. This report presents a compilation and analyses of results from cross-hole tracer tests with conservative tracers performed within various SKB investigations. The objectives of the study are to facilitate, improve and reduce uncertainties in predictive tracer modelling and to provide supporting information for SKB's safety assessment of a final repository of nuclear waste. More specifically, the focus of the report is the relationship between the tracer mean residence time and fracture hydraulic parameters, i.e. the relationship between mass balance aperture and fracture transmissivity, hydraulic diffusivity and apparent storativity. For 74 different combinations of pumping and injection section at six different test sites (Studsvik, Stripa, Finnsjoen, Aespoe, Forsmark, Laxemar), estimates of mass balance aperture from cross-hole tracer tests as well as transmissivity were extracted from reports or in the SKB database Sicada. For 28 of these combinations of pumping and injection section, estimates of hydraulic diffusivity and apparent storativity from hydraulic interference tests were also found. An empirical relationship between mass balance aperture and transmissivity was estimated, although some uncertainties for individual data exist. The empirical relationship between mass balance aperture and transmissivity presented in this study deviates considerably from other previously suggested relationships, such as the cubic law and transport aperture as suggested by /Dershowitz and Klise 2002/, /Dershowitz et al. 2002/ and /Dershowitz et al. 2003/, which also is discussed in this report. No clear and direct empirical relationship between mass balance aperture and hydraulic

An Efficient Method for Detection of Outliers in Tracer Curves Derived from Dynamic Contrast-Enhanced Imaging

Directory of Open Access Journals (Sweden)

Linning Ye

2018-01-01

Full Text Available Presence of outliers in tracer concentration-time curves derived from dynamic contrast-enhanced imaging can adversely affect the analysis of the tracer curves by model-fitting. A computationally efficient method for detecting outliers in tracer concentration-time curves is presented in this study. The proposed method is based on a piecewise linear model and implemented using a robust clustering algorithm. The method is noniterative and all the parameters are automatically estimated. To compare the proposed method with existing Gaussian model based and robust regression-based methods, simulation studies were performed by simulating tracer concentration-time curves using the generalized Tofts model and kinetic parameters derived from different tissue types. Results show that the proposed method and the robust regression-based method achieve better detection performance than the Gaussian model based method. Compared with the robust regression-based method, the proposed method can achieve similar detection performance with much faster computation speed.

Kinetics of the Dynamical Information Shannon Entropy for Complex Systems

International Nuclear Information System (INIS)

Yulmetyev, R.M.; Yulmetyeva, D.G.

1999-01-01

Kinetic behaviour of dynamical information Shannon entropy is discussed for complex systems: physical systems with non-Markovian property and memory in correlation approximation, and biological and physiological systems with sequences of the Markovian and non-Markovian random noises. For the stochastic processes, a description of the information entropy in terms of normalized time correlation functions is given. The influence and important role of two mutually dependent channels of the entropy change, correlation (creation or generation of correlations) and anti-correlation (decay or annihilation of correlation) is discussed. The method developed here is also used in analysis of the density fluctuations in liquid cesium obtained from slow neutron scattering data, fractal kinetics of the long-range fluctuation in the short-time human memory and chaotic dynamics of R-R intervals of human ECG. (author)

Predictions of tracer transport in interwell tracer tests at the C-Hole complex. Yucca Mountain site characterization project report milestone 4077

International Nuclear Information System (INIS)

Reimus, P.W.

1996-09-01

This report presents predictions of tracer transport in interwell tracer tests that are to be conducted at the C-Hole complex at the Nevada Test Site on behalf of the Yucca Mountain Site Characterization Project. The predictions are used to make specific recommendations about the manner in which the tracer test should be conducted to best satisfy the needs of the Project. The objective of he tracer tests is to study flow and species transport under saturated conditions in the fractured tuffs near Yucca Mountain, Nevada, the site of a potential high-level nuclear waste repository. The potential repository will be located in the unsaturated zone within Yucca Mountain. The saturated zone beneath and around the mountain represents the final barrier to transport to the accessible environment that radionuclides will encounter if they breach the engineered barriers within the repository and the barriers to flow and transport provided by the unsaturated zone. Background information on the C-Holes is provided in Section 1.1, and the planned tracer testing program is discussed in Section 1.2

TMI cable tracer operation and maintenance manual for assembly 417910

International Nuclear Information System (INIS)

Sumstine, R.L.

1983-11-01

This manual provides technical information and instructions to operate and maintain the cable tracer designed for the Three Mile Island (TMI) Unit 2 Reactor Building. The TMI cable tracer was developed to allow TMI personnel to trace cables in cable trays that may be tested or sectioned for destructive examination

Plasma norepinephrine in humans: limitations in assessment of whole body norepinephrine kinetics and plasma clearance

DEFF Research Database (Denmark)

Christensen, N J; Henriksen, Jens Henrik Sahl

1989-01-01

]IP and 131I-hippurate, whole body clearance from plasma of [3H]NE, as obtained from infusion rate divided by plasma concentration of tracer [1.74 +/- 0.64 (SD) 1/min] was significantly higher than the value obtained by total tracer infusion divided by total plasma area of tracer (1.27 +/- 0.51, P less than 0...... irreversible removal of NE, is smaller than previously estimated due to recycling through the plasma space. Attention has been drawn to limitations of [3H]NE kinetics....

Development and evaluation of a tracer-injection hydrothermal technique for studies of waste package interactions

International Nuclear Information System (INIS)

Jones, T.E.; Coles, D.G.; Britton, R.C.; Burnell, J.R.

1986-11-01

A tracer-injection system has been developed for use in characterizing reactions of waste package materials under hydrothermal conditions. High-pressure liquid chromatographic instrumentation has been coupled with Dickson-type rocking autoclaves to allow injection of selected components into the hydrothermal fluid while maintaining run temperature and pressure. Hydrothermal experiments conducted using this system included the interactions of depleted uranium oxide and Zircaloy-4 metal alloy discs with trace levels of 99 Tc and non-radioactive Cs and I in a simulated groundwater matrix. After waste-package components and simulated waste forms were pre-conditioned in the autoclave systems (usually 4 to 6 weeks), known quantities of tracer-doped fluids were injected into the autoclaves' gold reaction bag at run conditions. Time-sequenced sampling of the hydrothermal fluid providing kinetic data on the reactions of tracers with waste package materials. The injection system facilitates the design of experiments that will better define ''steady-state'' fluid compositions in hydrothermal reactions. The injection system will also allow for the formation of tracer-bearing solid phases in detectable quantities

Preclinical Evaluation of RYM1, a Matrix Metalloproteinase-Targeted Tracer for Imaging Aneurysm.

Science.gov (United States)

Toczek, Jakub; Ye, Yunpeng; Gona, Kiran; Kim, Hye-Yeong; Han, Jinah; Razavian, Mahmoud; Golestani, Reza; Zhang, Jiasheng; Wu, Terence L; Jung, Jae-Joon; Sadeghi, Mehran M

2017-08-01

Matrix metalloproteinases (MMPs) play a key role in abdominal aortic aneurysm (AAA) development. Accordingly, MMP-targeted imaging provides important information regarding vessel wall biology in the course of aneurysm development. Given the small size of the vessel wall and its proximity with blood, molecular imaging of aneurysm optimally requires highly sensitive tracers with rapid blood clearance. To this end, we developed a novel hydrosoluble zwitterionic MMP inhibitor, RYM, on the basis of which a pan-MMP tracer, RYM1, was designed. Here, we describe the development and preclinical evaluation of RYM1 in comparison with RP805, a commonly used pan-MMP tracer in murine models of aneurysm. Methods: The macrocyclic hydroxamate-based pan-MMP inhibitor coupled with 6-hydrazinonicotinamide, RYM1, was synthesized and labeled with 99m Tc. Radiochemical stability of 99m Tc-RYM1 was evaluated by radio-high-performance liquid chromatography analysis. Tracer blood kinetics and biodistribution were compared with 99m Tc-RP805 in C57BL/6J mice ( n = 10). 99m Tc-RYM1 binding to aneurysm and specificity were evaluated by quantitative autoradiography in apolipoprotein E-deficient (apoE -/- ) mice with CaCl 2 -induced carotid aneurysm ( n = 11). Angiotensin II-infused apoE -/- ( n = 16) mice were used for small-animal SPECT/CT imaging. Aortic tissue MMP activity and macrophage marker CD68 expression were assessed by zymography and reverse-transcription polymerase chain reaction. Results: RYM1 showed nanomolar range inhibition constants for several MMPs. 99m Tc-RYM1 was radiochemically stable in mouse blood for 5 h and demonstrated rapid renal clearance and lower blood levels in vivo compared with 99m Tc-RP805. 99m Tc-RYM1 binding to aneurysm and its specificity were shown by autoradiography in carotid aneurysm. Angiotensin II infusion in apoE -/- mice for 4 wk resulted in AAA formation in 36% (4/11) of surviving animals. In vivo 99m Tc-RYM1 small-animal SPECT/CT images showed

Using radioactive tracer technique in municipal hygiene

International Nuclear Information System (INIS)

Yurasova, O.I.

1974-01-01

Work of the A. N. Syrsin Institute of General and Municiapl Hygiene using raidoactive tracers is reviewed. The studies include research on protein metabolism in the living organism following action of unfavorable factors of the environment; determination of the paths of introduction into the organism of substances with an alien composition; and study of the rate of resorption of subcutaneous papuli. Results are shown of radioactive-tracer studies on the mechanism of action of poisonous substances on the living organism and of migration of alien chemical compounds in the organism and in objects in the environment. It is concluded that the radioactive tracer method has wide application in municipal hygiene and sanitary microbiology. The absence of laborious operations, economy of time, precision of the experiments, and the possibility of obtaining additional information on the mechanism of action of poisonous substances on the organism and the low cost of such studies compared with other methods makes the radioactive tracer method economically attractive. The studies made show the various types of use of the method in municipal hygiene and sanitary microbiology

Using radioactive tracer technique in municipal hygiene

Energy Technology Data Exchange (ETDEWEB)

Yurasova, O I [Institut Obshchej i Kommunal' noj Gigieny, Moscow (USSR)

1974-01-01

Work of the A. N. Syrsin Institute of General and Municiapl Hygiene using raidoactive tracers is reviewed. The studies include research on protein metabolism in the living organism following action of unfavorable factors of the environment; determination of the paths of introduction into the organism of substances with an alien composition; and study of the rate of resorption of subcutaneous papuli. Results are shown of radioactive-tracer studies on the mechanism of action of poisonous substances on the living organism and of migration of alien chemical compounds in the organism and in objects in the environment. It is concluded that the radioactive tracer method has wide application in municipal hygiene and sanitary microbiology. The absence of laborious operations, economy of time, precision of the experiments, and the possibility of obtaining additional information on the mechanism of action of poisonous substances on the organism and the low cost of such studies compared with other methods makes the radioactive tracer method economically attractive. The studies made show the various types of use of the method in municipal hygiene and sanitary microbiology.

Environmental Tracers

Directory of Open Access Journals (Sweden)

Trevor Elliot

2014-10-01

Full Text Available Environmental tracers continue to provide an important tool for understanding the source, flow and mixing dynamics of water resource systems through their imprint on the system or their sensitivity to alteration within it. However, 60 years or so after the first isotopic tracer studies were applied to hydrology, the use of isotopes and other environmental tracers are still not routinely necessarily applied in hydrogeological and water resources investigations where appropriate. There is therefore a continuing need to promote their use for developing sustainable management policies for the protection of water resources and the aquatic environment. This Special Issue focuses on the robustness or fitness-for-purpose of the application and use of environmental tracers in addressing problems and opportunities scientifically, to promote their wider use and to address substantive issues of vulnerability, sustainability, and uncertainty in (groundwater resources systems and their management.

Study of the mineralization of coral implanted in vivo by radioactive tracers

International Nuclear Information System (INIS)

Irigaray, J.L.; Sauvage, T.; Oudadesse, H.; El Fadl, H.; Lefaivre, J.; Barlet, J.P.; Trevers, S.; Tixer, H.

1993-01-01

Coral has been used for the last ten years as bone substitution in the body because of its mechanical and osteoconductor properties. Primary studies have shown, for the first time, the quantitative behaviour of the atomic components. A biocoral implanted 'in vivo' was studied by some physical method of analysis. The natural biocorals used are the calcium carbonated exoskeletons built by Madrepian coral polyps. Neutron activation analysis showed that initial coral, essentially CaCO 3 , becomes a new material which has a mineral composition close to that of bone. The calcification mechanism of this implant was studied by using radioactive tracers. The tracer kinetics of calcium biomaterial have been established in the blood circuit and its use was shown by the organism for skeleton mineralization. (author) 8 refs.; 6 figs.; 4 tabs

Use of natural geochemical tracers to improve reservoir simulation models

Energy Technology Data Exchange (ETDEWEB)

Huseby, O.; Chatzichristos, C.; Sagen, J.; Muller, J.; Kleven, R.; Bennett, B.; Larter, S.; Stubos, A.K.; Adler, P.M.

2005-01-01

This article introduces a methodology for integrating geochemical data in reservoir simulations to improve hydrocarbon reservoir models. The method exploits routine measurements of naturally existing inorganic ion concentration in hydrocarbon reservoir production wells, and uses the ions as non-partitioning water tracers. The methodology is demonstrated on a North Sea field case, using the field's reservoir model, together with geochemical information (SO{sub 4}{sup 2}, Mg{sup 2+} K{sup +}, Ba{sup 2+}, Sr{sup 2+}, Ca{sup 2+}, Cl{sup -} concentrations) from the field's producers. From the data-set we show that some of the ions behave almost as ideal sea-water tracers, i.e. without sorption to the matrix, ion-exchange with the matrix or scale-formation with other ions in the formation water. Moreover, the dataset shows that ion concentrations in pure formation-water vary according to formation. This information can be used to allocate produced water to specific water-producing zones in commingled production. Based on an evaluation of the applicability of the available data, one inorganic component, SO{sub 4}{sup 2}, is used as a natural seawater tracer. Introducing SO{sub 4}{sup 2} as a natural tracer in a tracer simulation has revealed a potential for improvements of the reservoir model. By tracking the injected seawater it was possible to identify underestimated fault lengths in the reservoir model. The demonstration confirms that geochemical data are valuable additional information for reservoir characterization, and shows that integration of geochemical data into reservoir simulation procedures can improve reservoir simulation models. (author)

Tracer tests - possibilities and limitations. Experience from SKB fieldwork: 1977-2007

Energy Technology Data Exchange (ETDEWEB)

Loefgren, Martin; Crawford, James; Elert, Mark (Kemakta Konsult AB, Stockholm (SE))

2007-09-15

Tracer tests have played, and still play, a central role in investigations relating to the understanding of radionuclide retention processes in the field. At present there is a debate within the scientific community concerning how, and to what extent, tracer tests can be used to evaluate large-scale and long-term transport and retardation of radionuclides and other solutes of interest for Safety Assessment of repositories for spent nuclear fuel. In this report the SKB fieldwork on tracer tests performed at Swedish sites from 1977 to 2007 is described and discussed. Furthermore, the knowledge and process understanding evolved during the decades of radionuclide transport experiments and modelling within the SKB programme is summarised. One of the main objectives of this report is to discuss what data and knowledge can be extracted from different in situ tests in a robust fashion. Given the level of complexity associated with transport processes that may occur over the timescale of a tracer test, the utility of tracer tests is considered in the context of evidence-based interpretations of data which we characterise in the form of a sequence of questions of increasing complexity. The complexity of this sequence ranges from whether connection can be confirmed between injection and withdrawal points to whether quantitative data can be extrapolated from a tracer test to be subsequently used in Safety Assessment. The main findings of this report are that: Field scale tracer tests can confirm flow connectivity. Field scale tracer tests confirm the existence of retention. Field scale tracer tests alone can only broadly substantiate our process understanding. However, if performing extensive Site Characterisation and integrating the tracer test results with the full range of geoscientific information available, much support can be given to our process understanding. Field scale tracer tests can deliver the product of the material property group MPG and the F-factor, valid

Tracer techniques in karst hydrogeology. Application to the location of karst aquifers

International Nuclear Information System (INIS)

Mangin, A.; Molinari, J.

1976-01-01

From the recent progress in karst aquifer simulation techniques and the improved knowledge of tracers, the old-established tracer technique has become an invaluable instrument for hydrogeological survey work. Typical information obtainable includes karst system boundaries features and location of hydrodynamic discontinuities, flow variation in both space and time. Tracer methods are a basic requirement for investigation of karst groundwater supplies and determining protection zones for water supply points [fr

Tracer studies with aortic infusion result in improper tracer distribution

International Nuclear Information System (INIS)

Wisneski, J.A.; Brooks, G.A.; Neese, R.A.; Stanley, W.C.; Morris, D.L.; Gertz, E.W.

1986-01-01

It has been suggested that lactate turnover can be accurately assessed by infusing radioactive lactate tracer into the aorta and sampling blood in the vena cava. However, there may be streaming of newly infused tracer in the aorta, resulting in a nonuniform arterial specific activity (SA). Furthermore vena caval blood may not be representative of mixed venous blood. The authors examined this problem in 7 anesthetized dogs with sampling catheters in the pulmonary (PA), carotid (CA), and femoral (FA) arteries, and the superior (SVC) and inferior (IVC) vena cavi. [1- 14 C]lactate was continuously infused into the left ventricle through a catheter introduced through the femoral artery. The same SA (dpm/μmol) was found in the CA and FA, indicating adequate mixing of newly infused tracer with trace. Three dogs showed differences between SVC, IVC and PA, suggesting a mixed venous sample can not be obtained from the VC. When the catheter was moved into the aorta, wide differences in SA appeared between the CA and FA, clearly reflecting streaming of tracer. These differences also appeared in the SVC and IVC. In conclusion, adequate mixing does not occur between tracer and trace in arterial blood with aortic infusion. Further, VC sampling will not give a consistent mixed venous SA. Therefore, for practical reasons, aortic tracer infusion with vena caval sampling will lead to erroneous turnover values

Simulation of variable-density flow and transport of reactive and nonreactive solutes during a tracer test at Cape Cod, Massachusetts

Science.gov (United States)

Zhang, Hubao; Schwartz, Frank W.; Wood, Warren W.; Garabedian, S.P.; LeBlanc, D.R.

1998-01-01

A multispecies numerical code was developed to simulate flow and mass transport with kinetic adsorption in variable-density flow systems. The two-dimensional code simulated the transport of bromide (Br−), a nonreactive tracer, and lithium (Li+), a reactive tracer, in a large-scale tracer test performed in a sand-and-gravel aquifer at Cape Cod, Massachusetts. A two-fraction kinetic adsorption model was implemented to simulate the interaction of Li+ with the aquifer solids. Initial estimates for some of the transport parameters were obtained from a nonlinear least squares curve-fitting procedure, where the breakthrough curves from column experiments were matched with one-dimensional theoretical models. The numerical code successfully simulated the basic characteristics of the two plumes in the tracer test. At early times the centers of mass of Br− and Li+ sank because the two plumes were closely coupled to the density-driven velocity field. At later times the rate of downward movement in the Br− plume due to gravity slowed significantly because of dilution by dispersion. The downward movement of the Li+ plume was negligible because the two plumes moved in locally different velocity regimes, where Li+ transport was retarded relative to Br−. The maximum extent of downward transport of the Li+ plume was less than that of the Br− plume. This study also found that at early times the downward movement of a plume created by a three-dimensional source could be much more extensive than the case with a two-dimensional source having the same cross-sectional area. The observed shape of the Br− plume at Cape Cod was simulated by adding two layers with different hydraulic conductivities at shallow depth across the region. The large dispersion and asymmetrical shape of the Li+ plume were simulated by including kinetic adsorption-desorption reactions.

Tracer migration experiments in the Stripa mine 1980-1991

International Nuclear Information System (INIS)

Birgersson, L.; Widen, H.; Aagren, T.; Neretnieks, I.

1992-05-01

During more than 10 years, tracer experiments have been performed in the Stripa mine as part of the Stripa project to investigate the properties of both 'average' fractured rock and fracture zones. Experiments have been performed that have ranged from a few decimeters, to examine the diffusion into the rock matrix, up to tracer migration to a drift more than 50 meters from the injection point. This report compiles the results and experience that have been gained from all these tracer experiments. The experiments that are described in this report are: * The in-situ diffusion experiment where simultaneous flow and diffusion of tracers in undisturbed rock were studied over more than 3 years to validate diffusivities obtained under laboratory conditions. * Migration in a single fracture where water flow distribution and tracer transport were studied using both conservative and sorbing tracers over migration distances up to 10 meters. * The 3-D migration experiment where water inflow and tracer transport to a drift covered with 350 plastic sheet were investigated to get information on flow porosity, dispersion and channeling. The transport distances were between 10 and 56 meters from the injection points to the drift. * The channeling experiments in which the aim was to examine the channeling properties of single fractures in detail. Pressure pulse tests and tracer experiments were performed over a distances of 2 meters. * The tracer migration experiment in the validation drift where the tracer were injected mainly in a fracture zone and the collection was inside both a drift covered with plastic sheets similar to in the 3-D experiment as well as in a borehole. The distances between injection and sampling location were between 10 and 25 meters. (57 refs.) (au)

Long residence times - bad tracer tests?

Science.gov (United States)

Ghergut, Julia; Behrens, Horst; Sauter, Martin

2015-04-01

process, and later on during sample aeration); the adsorbed and/or co-precipitated tracer amounts appear to be non-zero, but their accurate metering was not completed to date. Thus, a conservative estimate of cumulative tracer recovery amounts to (at least) 2 parts-per-thousand for the first 700,000 m3 of fluid turnover within the geothermal well doublet. Neither do such recovery values automatically imply 'bad news' (poor inter-well connectivity), nor do they appear as implausibly low (cf. fig. 2 of [3]), considering the possibility of major vertical drainage along the large-scale fault zone that isolates the 'aquifer basin' around the re-injection well from the 'aquifer catchment' around the production well, along with the prospect of transport-effective porosity and/or thickness within these 'aquifers' being rather high, due to extensive fissuring/fracturing. In more general terms, we argue that (a) inter-well flow-path spikings are still worthwhile being conducted even in large-scale hydrothermal reservoirs; (b) results gained from single-well tests [3] can never serve as a substitute for the kind of information (primarily: residence time distribution RTD, or flow-storage repartition FSR) being expected from inter-well tests; (c) tracer species that are 'novel' in terms of thermo-/reactivity/sorptivity/exchange at phase interfaces and thus involve some transport-retarding process cannot alleviate the frustration associated with long RT; (d) augmenting the tracer quantity Minj to use for inter-well spiking might render the tracer signal detectable, say, one or two years earlier, but it does not make FSR available sooner, since Minj cannot alter the RTD of fluids traveling through the reservoir; moreover, for inter-well configurations and reservoir structures typical of the Upper Rhine Rift Valley, the Minj augmenting factors necessary to render tracer signals detectable 1 or 2 years earlier mostly range beyond the limits of the reasonably-recommendable (e. g., for

Neural estimation of kinetic rate constants from dynamic PET-scans

DEFF Research Database (Denmark)

Fog, Torben L.; Nielsen, Lars Hupfeldt; Hansen, Lars Kai

1994-01-01

A feedforward neural net is trained to invert a simple three compartment model describing the tracer kinetics involved in the metabolism of [18F]fluorodeoxyglucose in the human brain. The network can estimate rate constants from positron emission tomography sequences and is about 50 times faster ...

Analysis of infiltration through mill tailings using a bromide tracer

International Nuclear Information System (INIS)

Lewis, G.J.; Stephens, D.B.

1985-01-01

Infiltration of precipitation into tailings impoundments as a means of recharge to underlying materials is often considered insignificant, particularly in arid and semi-arid environments. A series of experiments was performed to investigate the behavior of infiltrated precipitation into tailing soils, by the use of a bromide tracer. A bromide tracer was applied to the surface of columns driven into the tailings to monitor downward advancement of tracer-laden water. Controlled laboratory experiments on the behavior of the bromide tracer under varying precipitation events and initial soil moisture contents were also conducted. Results indicate that a definite downward migration of infiltrated precipitation occurs, particularly with large magnitude precipitation events, and that, eventually, some fraction of the infiltrated precipitation may continue downward below the zone affected by evaporation. The use of an artificially applied bromide tracer to monitor depth of infiltration of precipitation is a simple, safe technique that can provide valuable information for long-term tailings management strategies at low cost

Tracers tor the investigation of cerebral presynaptic dopaminergic function with positron emission tomography

International Nuclear Information System (INIS)

Firnau, G.; Chirakal, R.; Nahmias, C.; Garnett, E.S.

1991-01-01

Two pharmacologic concepts, open-quotes metabolic precursorsclose quotes and open-quotes enzyme inhibitorsclose quotes have been applied to the design of PET tracers for the metabolic aspects of the neurotransmitter dopamine. As the result, highly useful, positron-emitting radiotracers have been developed with which to visualize and measure the cerebral distribution and metabolism of dopaminergic neurons. Positron emitter-labeled DOPA, particularly 6-[ 18 F]fluoro-L-DOPA, is being used to obtain information about the neurochemical anatomy of the dopamine system, and potentially, the rate constant of dopamine biosynthesis. 6-[ 18 F]Fluoro-L- meta-tyrosine delineates the dopaminergic structures even better than 6-[ 18 F]fluoro-L-DOPA but cannot provide kinetic information about dopamine biosynthesis. The in vivo activity of the enzyme aromatic L-aminoacid decarboxylase and that of monoamine oxidase types A and B can be measured with a-fluoro-methyl-6-[ 18 F]fluoro-L-DOPA, [ 11 C]clorgyline and L-[ 11 C]deprenyl, respectively. Thus, neuropharmacologic investigations of human presynaptic dopamine pharmacology are now possible in vivo

Estimation of Uncertainty in Tracer Gas Measurement of Air Change Rates

Directory of Open Access Journals (Sweden)

Atsushi Iizuka

2010-12-01

Full Text Available Simple and economical measurement of air change rates can be achieved with a passive-type tracer gas doser and sampler. However, this is made more complex by the fact many buildings are not a single fully mixed zone. This means many measurements are required to obtain information on ventilation conditions. In this study, we evaluated the uncertainty of tracer gas measurement of air change rate in n completely mixed zones. A single measurement with one tracer gas could be used to simply estimate the air change rate when n = 2. Accurate air change rates could not be obtained for n ≥ 2 due to a lack of information. However, the proposed method can be used to estimate an air change rate with an accuracy of

Development and Characterization of a Fluorescent Tracer for the Free Fatty Acid Receptor 2 (FFA2/GPR43)

DEFF Research Database (Denmark)

Hansen, Anders Højgaard; Sergeev, Eugenia; Pandey, Sunil K.

2017-01-01

The free fatty acid receptor 2 (FFA2/GPR43) is considered a potential target for treatment of metabolic and inflammatory diseases. Here we describe the development of the first fluorescent tracer for FFA2 intended as a tool for assessment of thermodynamic and kinetic binding parameters of unlabel...

Kinetic Modeling of the Tau PET Tracer 18F-AV-1451 in Human Healthy Volunteers and Alzheimer Disease Subjects.

Science.gov (United States)

Barret, Olivier; Alagille, David; Sanabria, Sandra; Comley, Robert A; Weimer, Robby M; Borroni, Edilio; Mintun, Mark; Seneca, Nicholas; Papin, Caroline; Morley, Thomas; Marek, Ken; Seibyl, John P; Tamagnan, Gilles D; Jennings, Danna

2017-07-01

18 F-AV-1451 is currently the most widely used of several experimental tau PET tracers. The objective of this study was to evaluate 18 F-AV-1451 binding with full kinetic analysis using a metabolite-corrected arterial input function and to compare parameters derived from kinetic analysis with SUV ratio (SUVR) calculated over different imaging time intervals. Methods: 18 F-AV-1451 PET brain imaging was completed in 16 subjects: 4 young healthy volunteers (YHV), 4 aged healthy volunteers (AHV), and 8 Alzheimer disease (AD) subjects. Subjects were imaged for 3.5 h, with arterial blood samples obtained throughout. PET data were analyzed using plasma and reference tissue-based methods to estimate the distribution volume, binding potential (BP ND ), and SUVR. BP ND and SUVR were calculated using the cerebellar cortex as a reference region and were compared across the different methods and across the 3 groups (YHV, AHV, and AD). Results: AD demonstrated increased 18 F-AV-1451 retention compared with YHV and AHV based on both invasive and noninvasive analyses in cortical regions in which paired helical filament tau accumulation is expected in AD. A correlation of R 2 > 0.93 was found between BP ND (130 min) and SUVR-1 at all time intervals. Cortical SUVR curves reached a relative plateau around 1.0-1.2 for YHV and AHV by approximately 50 min, but increased in AD by up to approximately 20% at 110-130 min and approximately 30% at 160-180 min relative to 80-100 min. Distribution volume (130 min) was lower by 30%-35% in the YHV than AHV. Conclusion: Our data suggest that although 18 F-AV-1451 SUVR curves do not reach a plateau and are still increasing in AD, an SUVR calculated over an imaging window of 80-100 min (as currently used in clinical studies) provides estimates of paired helical filament tau burden in good correlation with BP ND , whereas SUVR sensitivity to regional cerebral blood changes needs further investigation. © 2017 by the Society of Nuclear Medicine and

Models for in vivo kinetic interactions of dopamine D2-neuroreceptors and 3-(2'-[18F]fluoroethyl)spiperone examined with positron emission tomography

International Nuclear Information System (INIS)

Bahn, M.M.; Huang, S.C.; Hawkins, R.A.; Satyamurthy, N.; Hoffman, J.M.; Barrio, J.R.; Mazziotta, J.C.; Phelps, M.E.

1989-01-01

The in vivo tracer kinetics of 3-(2'-[18F]fluoroethyl)spiperone (FESP) in the caudate/striatum and cerebellar regions of the human and monkey brain were studied with positron emission tomography (PET). The minimal model configuration that can describe the kinetics was determined statistically. Three two-compartment model configurations were found to be suitable for describing the kinetics in caudate/striatum and cerebellum: (1) a nonlinear model (five parameters) applicable to studies using nontracer (partially saturating) quantities of FESP in monkey striatum, (2) a linear four-parameter model applicable to the caudate/striatal and cerebellar kinetics in human and monkey studies with tracer quantities of FESP, and (3) a linear three-parameter model derived from the four-parameter model by assuming irreversible binding applicable to tracer studies of the human caudate. In the human studies, when the caudate kinetics (n = 4) were fit by model 2 (with four parameters), the value of the in vivo ligand dissociation constant kd was found to be 0.0015 +/- 0.0032/min. The three-parameter model (model 3) was found to fit the data equally well: this model is equivalent to model 2 with kd set to zero. In the monkey studies, it was found that for short (90 min) studies using tracer quantities of FESP, model 2 fit the striatal kinetics better than model 3. The parameters estimated using model 2 (four parameters) were in better agreement with those estimated by the nonlinear model (model 1) than those estimated using model 3 (three parameters). The use of a graphical approach gives estimates of the plasma-tissue fractional transport rate constant K1 and the net uptake constant K3 comparable to estimates using model 3 for both human and monkey studies

Radio-isotopic tracers

International Nuclear Information System (INIS)

Wolfangel, R.G.

1976-01-01

The invention concerns the dispersions that may be used for preparing radio-isotopic tracers, technetium labelled dispersions, processes for preparing these dispersions and their use as tracers. Technetium 99m sulphur colloids are utilized as scintillation tracers to give a picture of the reticulo-endothelial system, particularly the liver and spleen. A dispersion is provided which only requires the addition of a radioactive nuclide to form a radioactively labelled dispersion that can be injected as a tracer. It is formed of a colloid of tin sulphur dispersed in an aqueous buffer solution. Such a reagent has the advantage of being safe and reliable and is easier to use. The colloid can be prepared more quickly since additions of several different reagents are avoided. There is no need to heat up and no sulphuretted hydrogen, which is a toxic gas, is used [fr

Estimation of uncertainty in tracer gas measurement of air change rates.

Science.gov (United States)

Iizuka, Atsushi; Okuizumi, Yumiko; Yanagisawa, Yukio

2010-12-01

Simple and economical measurement of air change rates can be achieved with a passive-type tracer gas doser and sampler. However, this is made more complex by the fact many buildings are not a single fully mixed zone. This means many measurements are required to obtain information on ventilation conditions. In this study, we evaluated the uncertainty of tracer gas measurement of air change rate in n completely mixed zones. A single measurement with one tracer gas could be used to simply estimate the air change rate when n = 2. Accurate air change rates could not be obtained for n ≥ 2 due to a lack of information. However, the proposed method can be used to estimate an air change rate with an accuracy of air change rate can be avoided. The proposed estimation method will be useful in practical ventilation measurements.

Use of radioactive tracers in dynamic sedimentology

International Nuclear Information System (INIS)

Tola, Francois.

1982-01-01

In the first part, developments in the use of radioactive tracers in sedimentology are recalled together with the corresponding fields of application and the identities of the main users. The state-of-the-art in France is also discussed; The main characteristics of the method are then described and compared with those of more classical methods. The results that can be obtained with tracer methods are then outlined. The criteria employed to establish the granulometry characteristics of the tracer, the particular radioisotope to be used, and the masses and activities involved, are treated. A list is then given of the main isotopes available in France and their characteristics. The various different labelling techniques employed are studied together with their respective advantages and disadvantages. The special case of pelitic sediments is mentioned. The use of reduced model isotope generators, double labelling and applications to studies of the mud plug in the Gironde Estuary are also discussed. The methods and materials used for injecting and detecting tracers are described, emphasis being given to the economic factors associated with the use of radioactive tracers in sedimentology. The second part of the report contains two chapters: - studies of transport by driftage: presentation and analysis of results and the application of the Count Rate Balance method to obtain quantitative information on transport; - studies of in-suspension transport of fine sediments in the sea: the procedures adopted from the moment when the tracer is introduced up to the time when the results are analyzed and interpreted, enables the trajectories and mean velocities of the transported sediments to be determined together with their degree of dilution and their settling speeds and rates; it is also possible to investigate the evolution and horizontal dispersion of the sediments in this way. Results from recent experiments are presented in both parts of the report

Plasma kinetics of 14C-uric acid in bulls

International Nuclear Information System (INIS)

Cetinkaya, N.

1999-01-01

Plasma kinetics of uric acid were followed by 14C labelled uric acid to measure the effects of feed intake upon kinetic parameters. Two bulls (average L W 346±79 kg) were given an intravenous administration of a tracer (8-14C-uric acid, 250μCi/50 ml) by single injection via a jugular catheter. Animals were fed a mixed diet containing 30% wheat straw and 70% compounded feed as 95 and 60 % of the voluntary intake. Voluntary intakes were 8 kg/d as fed for two bulls. Blood samples, were collected at 0, 0.5,1, 2, 3, 4, 6, 8, 12, 16, 24 and 28 h after tracer administration. Fractional rates of clearance from the blood and pool size of compartments in the blood were estimated using plasma 8-14C-counts, following the method proposed by Chen and Franklin. The mean values of fractional rates (K 2,1 , K 1,2 ) and compartments pool size (V 1 , V 2 ) and the total pool size of compartments I and 2 at 60% and 95% feeding level were 1.97 and 1.44, 1.06 and 0.78; 76.9 L and 94.5 L, 137.01 L and 163.51 L; 214.0 L and 250.3 L respectively. Plasma kinetic parameters of 14C-uric acid were not affected at different feed intakes

Development of radioisotope tracer technology

International Nuclear Information System (INIS)

Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee; Park, Soon Chul; Lim, Dong Soon; Kim, Jae Ho; Lee, Jae Choon; Lee, Doo Sung; Cho, Yong Suk; Shin, Sung Kuan

2000-04-01

The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and to build a strong tracer group to support the local industries. In relation to the tracer technology in 1999, experiments to estimate the efficiencies of a sludge digester of a waste water treatment plant and a submerged biological reactor of a dye industry were conducted. As a result, the tracer technology for optimization of facilities related to wastewater treatment has been developed and is believed to contribute to improve their operation efficiency. The quantification of the experimental result was attempted to improve the confidence of tracer technology by ECRIN program which basically uses the MCNP simulation principle. Using thin layer activation technique, wear of tappet shim was estimated. Thin layer surface of a tappet shim was irradiated by proton beam and the correlation between the measured activity loss and the amount of wear was established. The equipment was developed to adjust the energy of proton which collides with the surface of tappet. The tracer project team has participated into the tracer test for estimating the efficiency of RFCC system in SK cooperation. From the experiment the tracer team has obtained the primary elements to be considered for judging the efficiency of RFCC unit. By developing the tracer techniques to test huge industrial units like RFCC, the tracer team will be able to support the local industries that require technical services to solve any urgent trouble. (author)

Experimental plan for tracer testing in the Culebra Dolomite at the WIPP site

International Nuclear Information System (INIS)

Beauheim, R.L.; Davies, P.B.

1992-01-01

This Experimental Plan provides a conceptual description of a proposed series of tracer tests to be conducted in the Culebra Dolomite Member of the Rustler Formation at the WIPP site. The new tracer tests are intended to address deficiencies that have been identified both in the performance and interpretation of previously conducted tracer tests' Tracer tests were conducted at the H-2 hydropad in 1980, at the H-6 hydropad in 1981, 1982, and 1983, at the H-4 hydropad from 1982 to 1984, at the H-3 hydropad in 1984, and at the H-11 hydropad in 1988. These tests were all performed over the entire 7-m thickness of the Culebra and, therefore, provided no information on the effects of vertical heterogeneity within the Culebra on transport. In addition, each of the previous tracer tests provided data only from 1 to 3 flow paths, allowing calibration of interpretive models but not validation of those models. The tracer tests at the H-3, H-6, and H-11 hydropads have been interpreted using a double-porosity continuum model (SWIFT 11) in which advective transport occurs through a uniform network of fractures while diffusion of tracer from the fractures to the porosity in the rock matrix causes a physical retardation of the transport. External reviewers, particularly participants in the international INTRAVAL program, have suggested that alternative mechanisms, such as fracture channeling, could explain the observed physical retardation and have recommended that additional tracer tests be designed and performed to distinguish among these mechanisms. The previous tracer tests also provided no information on chemical-retardation processes within the Culebra, which have been shown through performance-assessment calculations to have a large impact on cumulative releases of radionuclides from the WIPP to the accessible environment

Quadratic tracer dynamical models tobacco growth

International Nuclear Information System (INIS)

Qiang Jiyi; Hua Cuncai; Wang Shaohua

2011-01-01

In order to study the non-uniformly transferring process of some tracer dosages, we assume that the absorption of some tracer by tobacco is a quadratic function of the tracer quantity of the tracer in the case of fast absorption, whereas the exclusion of the tracer from tobacco is a linear function of the tracer quantity in the case of slow exclusion, after the tracer is introduced into tobacco once at zero time. A single-compartment quadratic dynamical model of Logistic type is established for the leaves of tobacco. Then, a two-compartment quadratic dynamical model is established for leaves and calms of the tobacco. Qualitative analysis of the models shows that the tracer applied to the leaves of the tobacco is excluded finally; however, the tracer stays at the tobacco for finite time. Two methods are also given for computing the parameters in the models. Finally, the results of the models are verified by the 32 P experiment for the absorption of tobacco. (authors)

Characterization of a managed aquifer recharge system using multiple tracers.

Science.gov (United States)

Moeck, Christian; Radny, Dirk; Popp, Andrea; Brennwald, Matthias; Stoll, Sebastian; Auckenthaler, Adrian; Berg, Michael; Schirmer, Mario

2017-12-31

Knowledge about the residence times of artificially infiltrated water into an aquifer and the resulting flow paths is essential to developing groundwater-management schemes. To obtain this knowledge, a variety of tracers can be used to study residence times and gain information about subsurface processes. Although a variety of tracers exists, their interpretation can differ considerably due to subsurface heterogeneity, underlying assumptions, and sampling and analysis limitations. The current study systematically assesses information gained from seven different tracers during a pumping experiment at a site where drinking water is extracted from an aquifer close to contaminated areas and where groundwater is artificially recharged by infiltrating surface water. We demonstrate that the groundwater residence times estimated using dye and heat tracers are comparable when the thermal retardation for the heat tracer is considered. Furthermore, major ions, acesulfame, and stable isotopes (δ 2 H and δ 18 O) show that mixing of infiltrated water and groundwater coming from the regional flow path occurred and a vertical stratification of the flow system exist. Based on the concentration patterns of dissolved gases (He, Ar, Kr, N 2 , and O 2 ) and chlorinated solvents (e.g., tetrachloroethene), three temporal phases are observed in the ratio between infiltrated water and regional groundwater during the pumping experiment. Variability in this ratio is significantly related to changes in the pumping and infiltration rates. During constant pumping rates, more infiltrated water was extracted, which led to a higher dilution of the regional groundwater. An infiltration interruption caused however, the ratio to change and more regional groundwater is extracted, which led to an increase in all concentrations. The obtained results are discussed for each tracer considered and its strengths and limitations are illustrated. Overall, it is demonstrated that aquifer heterogeneity and

Authentically radiolabelled Mn(II) complexes as bimodal PET/MR tracers

Energy Technology Data Exchange (ETDEWEB)

Vanasschen, Christian; Brandt, Marie; Ermert, Johannes [Institute of Neuroscience and Medicine, INM-5 - Nuclear Chemistry, Forschungszentrum Jülich (Germany); Neumaier, Bernd [Institute for Radiochemistry and Experimental Molecular Imaging, Medical Clinics, University of Cologne (Germany); Coenen, Heinz H [Institute of Neuroscience and Medicine, INM-5 - Nuclear Chemistry, Forschungszentrum Jülich (Germany)

2015-05-18

The development of small molecule bimodal PET/MR tracers is mainly hampered by the lack of dedicated preparation methods. Authentic radiolabelling of MR contrast agents ensures easy access to such probes: a ligand, chelating a paramagnetic metal ion (e.g. Mn2+) and the corresponding PET isotope (e.g. 52gMn), leads to a “cocktail mixture” where both imaging reporters exhibit the same pharmacokinetics. Paramagnetic [55Mn(CDTA)]2- shows an excellent compromise between thermodynamic stability, kinetic inertness and MR contrast enhancement. Therefore, the aim of this study was to develop new PET/MR tracers by labelling CDTA ligands with paramagnetic manganese and the β+-emitter 52gMn. N.c.a. 52gMn (t1/2: 5.6 d; Eβ+: 575.8 keV (29.6%)) was produced by proton irradiation of a natCr target followed by cation-exchange chromatography. CDTA was radiolabelled with n.c.a. 52gMn2+ in NaOAc buffer (pH 6) at RT. The complex was purified by RP-HPLC and its stability tested in PBS and blood plasma at 37°C. The redox stability was assessed by monitoring the T1 relaxation (20 MHz) in HEPES buffer (pH 7.4). A functionalized CDTA ligand was synthesized in 5 steps. [52gMn(CDTA)]2- was quantitatively formed within 30 min at RT. The complex was stable for at least 6 days in PBS and blood plasma at 37°C and no oxidation occurred within 7 months storage at RT. Labelling CDTA with an isotopic 52g/55Mn2+ mixture led to the corresponding bimodal PET/MR tracer. Furthermore, a functionalized CDTA ligand was synthesized with an overall yield of 18-25%. [52g/55Mn(CDTA)]2-, the first manganese-based bimodal PET/MR tracer prepared, exhibits excellent stability towards decomplexation and oxidation. This makes the functionalized CDTA ligand highly suitable for designing PET/MR tracers with high relaxivity or targeting properties.

Authentically radiolabelled Mn(II) complexes as bimodal PET/MR tracers

International Nuclear Information System (INIS)

Vanasschen, Christian; Brandt, Marie; Ermert, Johannes; Neumaier, Bernd; Coenen, Heinz H

2015-01-01

The development of small molecule bimodal PET/MR tracers is mainly hampered by the lack of dedicated preparation methods. Authentic radiolabelling of MR contrast agents ensures easy access to such probes: a ligand, chelating a paramagnetic metal ion (e.g. Mn2+) and the corresponding PET isotope (e.g. 52gMn), leads to a “cocktail mixture” where both imaging reporters exhibit the same pharmacokinetics. Paramagnetic [55Mn(CDTA)]2- shows an excellent compromise between thermodynamic stability, kinetic inertness and MR contrast enhancement. Therefore, the aim of this study was to develop new PET/MR tracers by labelling CDTA ligands with paramagnetic manganese and the β+-emitter 52gMn. N.c.a. 52gMn (t1/2: 5.6 d; Eβ+: 575.8 keV (29.6%)) was produced by proton irradiation of a natCr target followed by cation-exchange chromatography. CDTA was radiolabelled with n.c.a. 52gMn2+ in NaOAc buffer (pH 6) at RT. The complex was purified by RP-HPLC and its stability tested in PBS and blood plasma at 37°C. The redox stability was assessed by monitoring the T1 relaxation (20 MHz) in HEPES buffer (pH 7.4). A functionalized CDTA ligand was synthesized in 5 steps. [52gMn(CDTA)]2- was quantitatively formed within 30 min at RT. The complex was stable for at least 6 days in PBS and blood plasma at 37°C and no oxidation occurred within 7 months storage at RT. Labelling CDTA with an isotopic 52g/55Mn2+ mixture led to the corresponding bimodal PET/MR tracer. Furthermore, a functionalized CDTA ligand was synthesized with an overall yield of 18-25%. [52g/55Mn(CDTA)]2-, the first manganese-based bimodal PET/MR tracer prepared, exhibits excellent stability towards decomplexation and oxidation. This makes the functionalized CDTA ligand highly suitable for designing PET/MR tracers with high relaxivity or targeting properties.

Astrocytic tracer dynamics estimated from [1-11C]-acetate PET measurements

DEFF Research Database (Denmark)

Arnold, Andrea; Calvetti, Daniela; Gjedde, Albert

2015-01-01

We address the problem of estimating the unknown parameters of a model of tracer kinetics from sequences of positron emission tomography (PET) scan data using a statistical sequential algorithm for the inference of magnitudes of dynamic parameters. The method, based on Bayesian statistical...... inference, is a modification of a recently proposed particle filtering and sequential Monte Carlo algorithm, where instead of preassigning the accuracy in the propagation of each particle, we fix the time step and account for the numerical errors in the innovation term. We apply the algorithm to PET images...

Quantifying human vitamin kinetics using AMS

Energy Technology Data Exchange (ETDEWEB)

Hillegonds, D; Dueker, S; Ognibene, T; Buchholz, B; Lin, Y; Vogel, J; Clifford, A

2004-02-19

Tracing vitamin kinetics at physiologic concentrations has been hampered by a lack of quantitative sensitivity for chemically equivalent tracers that could be used safely in healthy people. Instead, elderly or ill volunteers were sought for studies involving pharmacologic doses with radioisotopic labels. These studies fail to be relevant in two ways: vitamins are inherently micronutrients, whose biochemical paths are saturated and distorted by pharmacological doses; and while vitamins remain important for health in the elderly or ill, their greatest effects may be in preventing slow and cumulative diseases by proper consumption throughout youth and adulthood. Neither the target dose nor the target population are available for nutrient metabolic studies through decay counting of radioisotopes at high levels. Stable isotopic labels are quantified by isotope ratio mass spectrometry at levels that trace physiologic vitamin doses, but the natural background of stable isotopes severely limits the time span over which the tracer is distinguishable. Indeed, study periods seldom ranged over a single biological mean life of the labeled nutrients, failing to provide data on the important final elimination phase of the compound. Kinetic data for the absorption phase is similarly rare in micronutrient research because the phase is rapid, requiring many consecutive plasma samples for accurate representation. However, repeated blood samples of sufficient volume for precise stable or radio-isotope quantitations consume an indefensible amount of the volunteer's blood over a short period. Thus, vitamin pharmacokinetics in humans has often relied on compartmental modeling based upon assumptions and tested only for the short period of maximal blood circulation, a period that poorly reflects absorption or final elimination kinetics except for the most simple models.

Dispersion of tracers by the oceanic eddy field modelling programme

International Nuclear Information System (INIS)

Richards, K.J.

1986-01-01

A numerical model has been developed to study the dispersion of tracers by the oceanic eddy field. The study is designed to investigate the horizontal and vertical structure of the eddies and how this structure is influenced by the bottom topography. It is found that hills and valleys have a strong effect on the eddies above them. The flow close to the bottom has a tendency to be steered by the height contours. The surface and bottom flows become decorrelated and the vertical variation of the kinetic energy of the eddies is increased with higher topographic features. (author)

Field tracer test for denitrification in a pyrite-bearing schist aquifer

International Nuclear Information System (INIS)

Pauwels, H.; Kloppmann, W.; Foucher, J.-C.; Martelat, A.; Fritsche, V.

1998-01-01

A small-scale artificial tracer test performed on a schist aquifer in Brittany has helped clarify mechanisms and kinetics of in situ autotrophic denitrification. NO 3 was injected as a pulse simultaneously with a conservative tracer - Br - . During the test, which lasted 210 h, 73% of the injected Br - was recovered, as against only 47% of the NO 3 . The 26% difference in the recovery of the two injected species is interpreted as being the result of denitrification, in part due to the direct oxidation of pyrite present in the solid aquifer according to the reaction: 5FeS 2 +14NO 3 - +4H + approaches7N 2 +10SO 4 2- +5Fe 2+ +2H 2 O, and in part due to subsequent iron oxidation according to the reaction: NO 3 - +5Fe 2+ +6H + approaches1/2N 2 +5Fe 3+ +3H 2 O. Despite the potential increase in SO 4 and Fe resulting from denitrification through pyrite oxidation, the concentrations of these elements in the groundwater remain moderate due to the precipitation of minerals such as jarosite and/or natroalunite. Tracer transfer takes place in a heterogeneous medium which, according to the breakthrough curves, can be simplified to a dual-porosity aquifer comprising a high-permeability (fractures or large fissures) medium of low porosity from which only minor denitrification of circulating NO 3 -bearing water was observed and a low-permeability (small fissures) medium of high porosity which induces a higher denitrification rate in the circulating NO 3 -bearing water. The kinetics of the denitrification reaction are high compared with results obtained for other environments and can be described by a first-order model with a half life of 7.9 days for the low-porosity medium and only 2.1 days for the high-porosity medium. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

[11C]UCB-A, a novel PET tracer for synaptic vesicle protein 2 A

International Nuclear Information System (INIS)

Estrada, Sergio; Lubberink, Mark; Thibblin, Alf; Sprycha, Margareta; Buchanan, Tim; Mestdagh, Nathalie; Kenda, Benoit; Mercier, Joel; Provins, Laurent; Gillard, Michel; Tytgat, Dominique; Antoni, Gunnar

2016-01-01

Introduction: Development of a selective and specific high affinity PET tracer, [ 11 C]UCB-A, for the in vivo study of SV2A expression in humans. Radiochemistry and preclinical studies in rats and pigs including development of a tracer kinetic model to determine V T . A method for the measurement of percent intact tracer in plasma was developed and the radiation dosimetry was determined in rats. Results: 3–5 GBq of [ 11 C]UCB-A could be produced with radiochemical purity exceeding 98% with a specific radioactivity of around 65 GBq/μmol. In vitro binding showed high selective binding towards SV2A. [ 11 C]UCB-A displayed a dose-dependent and reversible binding to SV2A as measured with PET in rats and pigs and the V T could be determined by Logan analysis. The dosimetry was favorable and low enough to allow multiple administrations of [ 11 C]UCB-A to healthy volunteers, and the metabolite analysis showed no sign of labeled metabolites in brain. Conclusions: We have developed the novel PET tracer, [ 11 C]UCB-A, that can be used to measure SV2A expression in vivo. The dosimetry allows up to 5 administrations of 400 MBq of [ 11 C]UCB-A in humans. Apart from measuring drug occupancy, as we have shown, the tracer can potentially be used to compare SV2A expression between individuals because of the rather narrow range of baseline V T values. This will have to be further validated in human studies.

Suitability of tracers

International Nuclear Information System (INIS)

Klotz, D.

1999-01-01

Hydrological tracer techniques are a means of making statements on the direction and speed of underground water. One of the simpler tasks is to find out whether there is hydrological communication between two given points. This requires a determination of the direction of flow, which places less exacting demands on the properties of the tracer than does the task of determining the flow velocity of underground water. Tracer methods can serve to infer from flow velocity the distance (flow) velocity, which is defined as the ratio between the distance between two points located in flow direction and the actual time it takes water to flow from one to the other [de

Proceedings of the atmospheric tracers and tracer application workshop

International Nuclear Information System (INIS)

Barr, S.; Gedayloo, T.

1979-12-01

In addition to presentations by participating members a general discussion was held in order to summarize and outline the goals and objectives of the workshop. A number of new low level background tracers such as heavy methanes, perfluorocarbons, multiply labeled isotopes such as 13 C 18 O 2 , helium 3, in addition to sample collection techniques and analytical methods for various tracers were discussed. This report is a summary of discussions and papers presented at this workshop

Deciphering robust reactor kinetic data using mutual information

International Nuclear Information System (INIS)

Kumar, P.T. Krishna

2007-01-01

Experimentalists use Chauvenets's criterion to check the quality of any measured data. Based on this criterion they rejected data having high degree of correlation. Multivariate techniques like principal component analysis used for analysis of these correlated data, does not provide any scope to minimize the effect of correlation. We propose a novel method using information theory and the technique of determinant inequalities developed by us to reduce the effect of correlation among these data without summarily rejecting them. We demonstrate the utility of our technique in transient measurements of kinetic parameters performed on the commercially advanced gas cooled reactor (CAGCR)

New horizons in cardiac innervation imaging. Introduction of novel 18F-labeled PET tracers

International Nuclear Information System (INIS)

Kobayashi, Ryohei; Chen, Xinyu; Werner, Rudolf A.; Lapa, Constantin; Javadi, Mehrbod S.; Higuchi, Takahiro

2017-01-01

Cardiac sympathetic nervous activity can be uniquely visualized by non-invasive radionuclide imaging techniques due to the fast growing and widespread application of nuclear cardiology in the last few years. The norepinephrine analogue 123 I-meta-iodobenzylguanidine ( 123 I-MIBG) is a single photon emission computed tomography (SPECT) tracer for the clinical implementation of sympathetic nervous imaging for both diagnosis and prognosis of heart failure. Meanwhile, positron emission tomography (PET) imaging has become increasingly attractive because of its higher spatial and temporal resolution compared to SPECT, which allows regional functional and dynamic kinetic analysis. Nevertheless, wider use of cardiac sympathetic nervous PET imaging is still limited mainly due to the demand of costly on-site cyclotrons, which are required for the production of conventional 11 C-labeled (radiological half-life, 20 min) PET tracers. Most recently, more promising 18 F-labeled (half-life, 110 min) PET radiopharmaceuticals targeting sympathetic nervous system have been introduced. These tracers optimize PET imaging and, by using delivery networks, cost less to produce. In this article, the latest advances of sympathetic nervous imaging using 18 F-labeled radiotracers along with their possible applications are reviewed. (orig.)

Tracer water transport and subgrid precipitation variation within atmospheric general circulation models

Science.gov (United States)

Koster, Randal D.; Eagleson, Peter S.; Broecker, Wallace S.

1988-03-01

A capability is developed for monitoring tracer water movement in the three-dimensional Goddard Institute for Space Science Atmospheric General Circulation Model (GCM). A typical experiment with the tracer water model follows water evaporating from selected grid squares and determines where this water first returns to the Earth's surface as precipitation or condensate, thereby providing information on the lateral scales of hydrological transport in the GCM. Through a comparison of model results with observations in nature, inferences can be drawn concerning real world water transport. Tests of the tracer water model include a comparison of simulated and observed vertically-integrated vapor flux fields and simulations of atomic tritium transport from the stratosphere to the oceans. The inter-annual variability of the tracer water model results is also examined.

Tracer water transport and subgrid precipitation variation within atmospheric general circulation models

Science.gov (United States)

Koster, Randal D.; Eagleson, Peter S.; Broecker, Wallace S.

1988-01-01

A capability is developed for monitoring tracer water movement in the three-dimensional Goddard Institute for Space Science Atmospheric General Circulation Model (GCM). A typical experiment with the tracer water model follows water evaporating from selected grid squares and determines where this water first returns to the Earth's surface as precipitation or condensate, thereby providing information on the lateral scales of hydrological transport in the GCM. Through a comparison of model results with observations in nature, inferences can be drawn concerning real world water transport. Tests of the tracer water model include a comparison of simulated and observed vertically-integrated vapor flux fields and simulations of atomic tritium transport from the stratosphere to the oceans. The inter-annual variability of the tracer water model results is also examined.

Thermodynamics of information processing based on enzyme kinetics: An exactly solvable model of an information pump.

Science.gov (United States)

Cao, Yuansheng; Gong, Zongping; Quan, H T

2015-06-01

Motivated by the recent proposed models of the information engine [Proc. Natl. Acad. Sci. USA 109, 11641 (2012)] and the information refrigerator [Phys. Rev. Lett. 111, 030602 (2013)], we propose a minimal model of the information pump and the information eraser based on enzyme kinetics. This device can either pump molecules against the chemical potential gradient by consuming the information to be encoded in the bit stream or (partially) erase the information initially encoded in the bit stream by consuming the Gibbs free energy. The dynamics of this model is solved exactly, and the "phase diagram" of the operation regimes is determined. The efficiency and the power of the information machine is analyzed. The validity of the second law of thermodynamics within our model is clarified. Our model offers a simple paradigm for the investigating of the thermodynamics of information processing involving the chemical potential in small systems.

Intracellular performance of tailored nanoparticle tracers in magnetic particle imaging

Energy Technology Data Exchange (ETDEWEB)

Arami, Hamed; Krishnan, Kannan M., E-mail: kannanmk@uw.edu [Department of Materials Science and Engineering, University of Washington, P.O. Box 352120, Seattle, Washington 98195-2120 (United States)

2014-05-07

Magnetic Particle Imaging (MPI) is a quantitative mass-sensitive, tracer-based imaging technique, with potential applications in various cellular imaging applications. The spatial resolution of MPI, in the first approximation, improves by decreasing the full width at half maximum (FWHM) of the field-derivative of the magnetization, dm/dH of the nanoparticle (NP) tracers. The FWHM of dm/dH depends critically on NPs’ size, size distribution, and their environment. However, there is limited information on the MPI performance of the NPs after their internalization into cells. In this work, 30 to 150 μg of the iron oxide NPs were incubated in a lysosome-like acidic buffer (0.2 ml, 20 mM citric acid, pH 4.7) and investigated by vibrating sample magnetometry, magnetic particle spectroscopy, transmission electron microscopy, and dynamic light scattering (DLS). The FWHM of the dm/dH curves of the NPs increased with incubation time and buffer to NPs ratio, consistent with a decrease in the median core size of the NPs from ∼20.1 ± 0.98 to ∼18.5 ± 3.15 nm. Further, these smaller degraded NPs formed aggregates that responded to the applied field by hysteretic reversal at higher field values and increased the FWHM. The rate of core size decrease and aggregation were inversely proportional to the concentration of the incubated NPs, due to their slower biodegradation kinetics. The results of this model experiment show that the MPI performance of the NPs in the acidic environments of the intracellular organelles (i.e., lysosomes and endosomes) can be highly dependent on their rate of internalization, residence time, and degradation.

Measuring serotonin synthesis: from conventional methods to PET tracers and their (pre)clinical implications

Energy Technology Data Exchange (ETDEWEB)

Visser, Anniek K.D.; Waarde, Aren van; Willemsen, Antoon T.M. [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); Bosker, Fokko J. [University of Groningen, University Medical Center Groningen, University Center of Psychiatry, Groningen (Netherlands); Luiten, Paul G.M. [University of Groningen, Center for Behavior and Neurosciences, Department of Molecular Neurobiology, Haren (Netherlands); Boer, Johan A. den [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); University of Groningen, University Medical Center Groningen, University Center of Psychiatry, Groningen (Netherlands); Kema, Ido P. [University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen (Netherlands); Dierckx, Rudi A.J.O. [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); University Hospital Ghent, Department of Nuclear Medicine, Ghent (Belgium)

2011-03-15

The serotonergic system of the brain is complex, with an extensive innervation pattern covering all brain regions and endowed with at least 15 different receptors (each with their particular distribution patterns), specific reuptake mechanisms and synthetic processes. Many aspects of the functioning of the serotonergic system are still unclear, partially because of the difficulty of measuring physiological processes in the living brain. In this review we give an overview of the conventional methods of measuring serotonin synthesis and methods using positron emission tomography (PET) tracers, more specifically with respect to serotonergic function in affective disorders. Conventional methods are invasive and do not directly measure synthesis rates. Although they may give insight into turnover rates, a more direct measurement may be preferred. PET is a noninvasive technique which can trace metabolic processes, like serotonin synthesis. Tracers developed for this purpose are {alpha}-[{sup 11}C]methyltryptophan ([{sup 11}C]AMT) and 5-hydroxy-L-[{beta}-{sup 11}C]tryptophan ([{sup 11}C]5-HTP). Both tracers have advantages and disadvantages. [{sup 11}C]AMT can enter the kynurenine pathway under inflammatory conditions (and thus provide a false signal), but this tracer has been used in many studies leading to novel insights regarding antidepressant action. [{sup 11}C]5-HTP is difficult to produce, but trapping of this compound may better represent serotonin synthesis. AMT and 5-HTP kinetics are differently affected by tryptophan depletion and changes of mood. This may indicate that both tracers are associated with different enzymatic processes. In conclusion, PET with radiolabelled substrates for the serotonergic pathway is the only direct way to detect changes of serotonin synthesis in the living brain. (orig.)

Guidebook on radioisotope tracers in industry

International Nuclear Information System (INIS)

1990-01-01

The idea of using tracers (chemical, dyes, etc.) in the investigation of complex physical phenomena has always attracted the attention of scientists and engineers. When radioactive isotopes became available it was immediately recognized that they offered an almost ideal solution to tracer selection. This book is devoted to reviewing the present status of the tracer method as such and to its applications to those branches of industry which have derived large benefits from the use of this modern technology. The main objectives of the IAEA's Industrial Applications and Chemistry Section is to help Member States in introducing to their own industries the different isotope and radiation techniques which have become available as a result of developments in the nuclear sciences. This section proposed the preparation of this guidebook, putting together various radiotracer methods and the experience obtained so far in their industrial use. Chapters 2 to 4 cover the general concept of tracers, technology and safety aspects, as well as data evaluation and interpretation. In chapter 5, therefore, general applications are discussed. In chapter 6, specialists in selected fields discuss their experience in radiotracer applications in various types of industrial activity. Most case studies are illustrated by at least one detailed example of an experiment carried out at an industrial installation. Current trends in the development of radiotracer methods are discussed in chapter 7, from both a theoretical and a practical viewpoint. Some possible new RTT applications in the future are also discussed here. Sealed radioactive sources are used almost as often as radioisotope tracers in industrial measurements. Annex I gives a short review of these techniques. Readers who are interested in the basic principles of radioisotope production will find the necessary information in Annex II. Annexes III, V and VI provide a demonstration of fundamental relations and properties; useful

Simulation and interpretation of inter-well tracer tests

Directory of Open Access Journals (Sweden)

Dugstad Øyvind

2013-05-01

Full Text Available In inter-well tracer tests (IWTT, chemical compounds or radioactive isotopes are used to label injection water and gas to establish well connections and fluid patterns in petroleum reservoirs. Tracer simulation is an invaluable tool to ease the interpretation of IWTT results and is also required for assisted history matching application of tracer data. In this paper we present a new simulation technique to analyse and interpret tracer results. Laboratory results are used to establish and test formulations of the tracer conservation equations, and the technique is used to provide simulated tracer responses that are compared with observed tracer data from an extensive tracer program. The implemented tracer simulation methodology use a fast post-processing of previously simulated reservoir simulation runs. This provides a fast, flexible and powerful method for analysing gas tracer behaviour in reservoirs. We show that simulation time for tracers can be reduced by factor 100 compared to solving the tracer flow equations simultaneously with the reservoir fluid flow equations. The post-processing technique, combined with a flexible built-in local tracer-grid refinement is exploited to reduce numerical smearing, particularly severe for narrow tracer pulses.

Concentration dynamics in lakes and reservoirs. Studies using radioactive tracers

International Nuclear Information System (INIS)

Gilath, Ch.

1983-01-01

The use of radioactive tracers for the investigation of concentration dynamics of inert soluble matter in lakes and reservoirs is reviewed. Shallow and deep stratified lakes are considered. The mechanism of mixing in lakes, flow pattern and input - output response are discussed. The methodology of the use of radioactive tracers for concentration dynamic studies is described. Examples of various investigations are reviewed. The dynamics of shallow lakes can be found and expressed in terms of transfer functions, axial dispersion models, residence time distributions and sometimes only semiquantitative information about the flow pattern. The dynamics of deep, stratified lakes is more complex and difficult to investigate with tracers. Flow pattern, horizontal and vertical eddy diffusivities, mass transfer between the hypolimnion and epilimnion are tools used for describing this dynamics. (author)

A New Kind of Single-Well Tracer Test for Assessing Subsurface Heterogeneity

Science.gov (United States)

Hansen, S. K.; Vesselinov, V. V.; Lu, Z.; Reimus, P. W.; Katzman, D.

2017-12-01

Single-well injection-withdrawal (SWIW) tracer tests have historically been interpreted using the idealized assumption of tracer path reversibility (i.e., negligible background flow), with background flow due to natural hydraulic gradient being an un-modeled confounding factor. However, we have recently discovered that it is possible to use background flow to our advantage to extract additional information about the subsurface. To wit: we have developed a new kind of single-well tracer test that exploits flow due to natural gradient to estimate the variance of the log hydraulic conductivity field of a heterogeneous aquifer. The test methodology involves injection under forced gradient and withdrawal under natural gradient, and makes use of a relationship, discovered using a large-scale Monte Carlo study and machine learning techniques, between power law breakthrough curve tail exponent and log-hydraulic conductivity variance. We will discuss how we performed the computational study and derived this relationship and then show an application example in which our new single-well tracer test interpretation scheme was applied to estimation of heterogeneity of a formation at the chromium contamination site at Los Alamos National Laboratory. Detailed core hole records exist at the same site, from which it was possible to estimate the log hydraulic conductivity variance using a Kozeny-Carman relation. The variances estimated using our new tracer test methodology and estimated by direct inspection of core were nearly identical, corroborating the new methodology. Assessment of aquifer heterogeneity is of critical importance to deployment of amendments associated with in-situ remediation strategies, since permeability contrasts potentially reduce the interaction between amendment and contaminant. Our new tracer test provides an easy way to obtain this information.

Xanthine tracers and their preparation

International Nuclear Information System (INIS)

Groman, E.V.; Cabelli, M.D.

1980-01-01

Compounds useful as tracers in the radioimmunoassay of xanthine derivatives such as theophylline and pharmacologically related drugs are described. They are substituted xanthines in which at least one substituted radical contains radioiodine. The tracers are made by linking radioiodinatable or preradioiodinated radicals to the xanthine derivative which is to be assayed. The tracers may be employed in known radioimmunoassay techniques. (author)

A Systematic Method For Tracer Test Analysis: An Example Using Beowawe Tracer Data

Energy Technology Data Exchange (ETDEWEB)

G. Michael Shook

2005-01-01

Quantitative analysis of tracer data using moment analysis requires a strict adherence to a set of rules which include data normalization, correction for thermal decay, deconvolution, extrapolation, and integration. If done correctly, the method yields specific information on swept pore volume, flow geometry and fluid velocity, and an understanding of the nature of reservoir boundaries. All calculations required for the interpretation can be done in a spreadsheet. The steps required for moment analysis are reviewed in this paper. Data taken from the literature is used in an example calculation.

Application of Radionuclide Tracer Techniques in Research on Bio-Effects of Carbon Nanoparticles

International Nuclear Information System (INIS)

Zhu Ying; Ran Tiecheng; Li Qingnuan; Xu Jingying; Li Wenxin

2010-01-01

There are few effective means to detect and analyze nanomaterials, therefore, radionuclide labeling and tracing techniques play an important role in the studies of interaction between nanoparticles and living systems. This paper briefly summarizes the main results from the application of radionuclide tracer techniques in the studies of interaction between carbon nanoparticles (fullerenes, carbon nanotubes and nano-carbon blacks) and animals and mammalian cells, cites the experimental information on absorption, distribution, metabolism and excretion of nanomaterials, and indicates the signification of these information in the drug development and bio-safety studies of nanomaterials. Based on the novel properties of carbon nanoparticles, the superiority of radionuclide tracer techniques over fluorescent labeling techniques is stressed. It is expected that the radionuclide tracer techniques have an increasing application prospect in the interdisciplinary fields of nanoscience and life science. (authors)

Thermodynamics of information processing based on enzyme kinetics: An exactly solvable model of an information pump

Science.gov (United States)

Cao, Yuansheng; Gong, Zongping; Quan, H. T.

2015-06-01

Motivated by the recent proposed models of the information engine [Proc. Natl. Acad. Sci. USA 109, 11641 (2012), 10.1073/pnas.1204263109] and the information refrigerator [Phys. Rev. Lett. 111, 030602 (2013), 10.1103/PhysRevLett.111.030602], we propose a minimal model of the information pump and the information eraser based on enzyme kinetics. This device can either pump molecules against the chemical potential gradient by consuming the information to be encoded in the bit stream or (partially) erase the information initially encoded in the bit stream by consuming the Gibbs free energy. The dynamics of this model is solved exactly, and the "phase diagram" of the operation regimes is determined. The efficiency and the power of the information machine is analyzed. The validity of the second law of thermodynamics within our model is clarified. Our model offers a simple paradigm for the investigating of the thermodynamics of information processing involving the chemical potential in small systems.

New horizons in cardiac innervation imaging. Introduction of novel {sup 18}F-labeled PET tracers

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Ryohei [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Nihon Medi-Physics Co., Ltd., Research Centre, Chiba (Japan); Chen, Xinyu [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); University Hospital of Wuerzburg, Comprehensive Heart Failure Center, Wuerzburg (Germany); Werner, Rudolf A. [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); University Hospital of Wuerzburg, Comprehensive Heart Failure Center, Wuerzburg (Germany); Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Lapa, Constantin [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Javadi, Mehrbod S. [Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Higuchi, Takahiro [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); University Hospital of Wuerzburg, Comprehensive Heart Failure Center, Wuerzburg (Germany); National Cerebral and Cardiovascular Center, Department of Biomedical Imaging, Research Institute, Suita (Japan)

2017-12-15

Cardiac sympathetic nervous activity can be uniquely visualized by non-invasive radionuclide imaging techniques due to the fast growing and widespread application of nuclear cardiology in the last few years. The norepinephrine analogue {sup 123}I-meta-iodobenzylguanidine ({sup 123}I-MIBG) is a single photon emission computed tomography (SPECT) tracer for the clinical implementation of sympathetic nervous imaging for both diagnosis and prognosis of heart failure. Meanwhile, positron emission tomography (PET) imaging has become increasingly attractive because of its higher spatial and temporal resolution compared to SPECT, which allows regional functional and dynamic kinetic analysis. Nevertheless, wider use of cardiac sympathetic nervous PET imaging is still limited mainly due to the demand of costly on-site cyclotrons, which are required for the production of conventional {sup 11}C-labeled (radiological half-life, 20 min) PET tracers. Most recently, more promising {sup 18}F-labeled (half-life, 110 min) PET radiopharmaceuticals targeting sympathetic nervous system have been introduced. These tracers optimize PET imaging and, by using delivery networks, cost less to produce. In this article, the latest advances of sympathetic nervous imaging using {sup 18}F-labeled radiotracers along with their possible applications are reviewed. (orig.)

Emission quantification using the tracer gas dispersion method: The influence of instrument, tracer gas species and source simulation

DEFF Research Database (Denmark)

Delre, Antonio; Mønster, Jacob; Samuelsson, Jerker

2018-01-01

The tracer gas dispersion method (TDM) is a remote sensing method used for quantifying fugitive emissions by relying on the controlled release of a tracer gas at the source, combined with concentration measurements of the tracer and target gas plumes. The TDM was tested at a wastewater treatment...... plant for plant-integrated methane emission quantification, using four analytical instruments simultaneously and four different tracer gases. Measurements performed using a combination of an analytical instrument and a tracer gas, with a high ratio between the tracer gas release rate and instrument...... precision (a high release-precision ratio), resulted in well-defined plumes with a high signal-to-noise ratio and a high methane-to-tracer gas correlation factor. Measured methane emission rates differed by up to 18% from the mean value when measurements were performed using seven different instrument...

Numerical flow models and their calibration using tracer based ages: Chapter 10

Science.gov (United States)

Sanford, W.

2013-01-01

Any estimate of ‘age’ of a groundwater sample based on environmental tracers requires some form of geochemical model to interpret the tracer chemistry (chapter 3) and is, therefore, referred to in this chapter as a tracer model age. the tracer model age of a groundwater sample can be useful for obtaining information on the residence time and replenishment rate of an aquifer system, but that type of data is most useful when it can be incorporated with all other information that is known about the groundwater system under study. groundwater fl ow models are constructed of aquifer systems because they are usually the best way of incorporating all of the known information about the system in the context of a mathematical framework that constrains the model to follow the known laws of physics and chemistry as they apply to groundwater flow and transport. It is important that the purpose or objective of the study be identified first before choosing the type and complexity of the model to be constructed, and to make sure such a model is necessary. The purpose of a modelling study is most often to characterize the system within a numerical framework, such that the hydrological responses of the system can be tested under potential stresses that might be imposed given future development scenarios. As this manual discusses dating as it applies to old groundwater, most readers are likely to be interested in studying regional groundwater flow systems and their water resource potential.

Tracer methodology: an appropriate tool for assessing compliance with accreditation standards?

Science.gov (United States)

Bouchard, Chantal; Jean, Olivier

2017-10-01

Tracer methodology has been used by Accreditation Canada since 2008 to collect evidence on the quality and safety of care and services, and to assess compliance with accreditation standards. Given the importance of this methodology in the accreditation program, the objective of this study is to assess the quality of the methodology and identify its strengths and weaknesses. A mixed quantitative and qualitative approach was adopted to evaluate consistency, appropriateness, effectiveness and stakeholder synergy in applying the methodology. An online questionnaire was sent to 468 Accreditation Canada surveyors. According to surveyors' perceptions, tracer methodology is an effective tool for collecting useful, credible and reliable information to assess compliance with Qmentum program standards and priority processes. The results show good coherence between methodology components (appropriateness of the priority processes evaluated, activities to evaluate a tracer, etc.). The main weaknesses are the time constraints faced by surveyors and management's lack of cooperation during the evaluation of tracers. The inadequate amount of time allowed for the methodology to be applied properly raises questions about the quality of the information obtained. This study paves the way for a future, more in-depth exploration of the identified weaknesses to help the accreditation organization make more targeted improvements to the methodology. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Isotopic marking and tracers

International Nuclear Information System (INIS)

Morel, F.

1997-01-01

The use of radioactive isotopes as tracers in biology has been developed thanks to the economic generation of the required isotopes in accelerators and nuclear reactors, and to the multiple applications of tracers in the life domain; the most usual isotopes employed in biology are carbon, hydrogen, phosphorus and sulfur isotopes, because these elements are present in most of organic molecules. Most of the life science knowledge appears to be dependent to the extensive use of nuclear tools and radioactive tracers; the example of the utilization of radioactive phosphorus marked ATP to study the multiple reactions with proteins, nucleic acids, etc., is given

beta-Methyl-15-p-iodophenylpentadecanoic acid metabolism and kinetics in the isolated rat heart.

Science.gov (United States)

DeGrado, T R; Holden, J E; Ng, C K; Raffel, D M; Gatley, S J

1989-01-01

The use of 15-p-iodophenyl-beta-methyl-pentadecanoic acid (beta Me-IPPA) as an indicator of long chain fatty acid (LCFA) utilization in nuclear medicine studies was evaluated in the isolated, perfused, working rat heart. Time courses of radioactivity (residue curves) were obtained following bolus injections of both beta Me-IPPA and its straight chain counterpart 15-p-iodophenyl-pentadecanoic acid (IPPA). IPPA kinetics clearly indicated flow independent impairment of fatty acid oxidation caused by the carnitine palmitoyltransferase I inhibitor 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). In contrast, beta Me-IPPA kinetics were insensitive to changes in fatty acid oxidation rate and net utilization of long chain fatty acid. Analysis of radiolabeled species in coronary effluent and heart homogenates showed the methylated fatty acid to be readily incorporated into complex lipids but a poor substrate for oxidation. POCA did not significantly alter metabolism of the tracer, suggesting that the tracer is poorly metabolized beyond beta Me-IPPA-CoA in the oxidative pathway.

beta. -methyl-15-p-iodophenylpentadecanoic acid metabolism and kinetics in the isolated rat heart

Energy Technology Data Exchange (ETDEWEB)

DeGrado, T.R.; Holden, J.E.; Ng, C.K.; Raffel, D.M.; Gatley, S.J.

1989-02-01

The use of 15-p-iodophenyl-..beta..-methyl-pentadecanoic acid (..beta..Me-IPPA) as an indicator of long chain fatty acid (LCFA) utilization in nuclear medicine studies was evaluated in the isolated, perfused, working rat heart. Time courses of radioactivity (residue curves) were obtained following bolus injections of both ..beta..Me-IPPA and its straight chain counterpart 15-p-iodophenyl-pentadecanoic acid (IPPA). IPPA kinetics clearly indicated flow independent impairment of fatty acid oxidation caused by the carnitine palmitoyltransferase I inhibitor 2(5(4-chlorophenyl)pentyl)oxirane-2-carboxylate (POCA). In contrast, ..beta..Me-IPPA kinetics were insensitive to changes in fatty acid oxidation rate and net utilization of long chain fatty acid. Analysis of radiolabeled species in coronary effluent and heart homogenates showed the methylated fatty acid to be readily incorporated into complex lipids but a poor substrate for oxidation. POCA did not significantly alter metabolism of the tracer, suggesting that the tracer is poorly metabolized beyond ..beta..Me-IPPA-CoA in the oxidative pathway.

Preclinical dynamic 18F-FDG PET - tumor characterization and radiotherapy response assessment by kinetic compartment analysis

International Nuclear Information System (INIS)

Roee, Kathrine; Aleksandersen, Thomas B.; Nilsen, Line B.; Hong Qu; Ree, Anne H.; Malinen, Eirik; Kristian, Alexandr; Seierstad, Therese; Olsen, Dag R.

2010-01-01

Background. Non-invasive visualization of tumor biological and molecular processes of importance to diagnosis and treatment response is likely to be critical in individualized cancer therapy. Since conventional static 18 F-FDG PET with calculation of the semi-quantitative parameter standardized uptake value (SUV) may be subject to many sources of variability, we here present an approach of quantifying the 18 F-FDG uptake by analytic two-tissue compartment modeling, extracting kinetic tumor parameters from dynamic 18 F-FDG PET. Further, we evaluate the potential of such parameters in radiotherapy response assessment. Material and methods. Male, athymic mice with prostate carcinoma xenografts were subjected to dynamic PET either untreated (n=8) or 24 h post-irradiation (7.5 Gy single dose, n=8). After 10 h of fasting, intravenous bolus injections of 10-15 MBq 18 F-FDG were administered and a 1 h dynamic PET scan was performed. 4D emission data were reconstructed using OSEM-MAP, before remote post-processing. Individual arterial input functions were extracted from the image series. Subsequently, tumor 18 F-FDG uptake was fitted voxel-by-voxel to a compartment model, producing kinetic parameter maps. Results. The kinetic model separated the 18 F-FDG uptake into free and bound tracer and quantified three parameters; forward tracer diffusion (k1), backward tracer diffusion (k2), and rate of 18 F-FDG phosphorylation, i.e. the glucose metabolism (k3). The fitted kinetic model gave a goodness of fit (r2) to the observed data ranging from 0.91 to 0.99, and produced parametrical images of all tumors included in the study. Untreated tumors showed homogeneous intra-group median values of all three parameters (k1, k2 and k3), whereas the parameters significantly increased in the tumors irradiated 24 h prior to 18 F-FDG PET. Conclusions. This study demonstrates the feasibility of a two-tissue compartment kinetic analysis of dynamic 18 F-FDG PET images. If validated, extracted

Single-well tracer methods for hydrogeologic evaluation of target aquifers

International Nuclear Information System (INIS)

Hall, S.H.

1994-11-01

Designing an efficient well field for an aquifer thermal energy storage (ATES) project requires measuring local groundwater flow parameters as well as estimating horizontal and vertical inhomogeneity. Effective porosity determines the volume of aquifer needed to store a given volume of heated or chilled water. Ground-water flow velocity governs the migration of the thermal plume, and dispersion and heat exchange along the flow path reduces the thermal intensity of the recovered plume. Stratigraphic variations in the aquifer will affect plume dispersion, may bias the apparent rate of migration of the plume, and can prevent efficient hydraulic communication between wells. Single-well tracer methods using a conservative flow tracer such as bromide, along with pumping tests and water-level measurements, provide a rapid and cost-effective means for estimating flow parameters. A drift-and-pumpback tracer test yields effective porosity and flow velocity. Point-dilution tracer testing, using new instrumentation for downhole tracer measurement and a new method for calibrating the point-dilution test itself, yields depth-discrete hydraulic conductivity as it is affected by stratigraphy, and can be used to estimate well transmissivity. Experience in conducting both drift-and-pumpback and point-dilution tests at three different test sites has yielded important information that highlights both the power and the limitations of the single-well tracer methods. These sites are the University of Alabama Student Recreation Center (UASRC) ATES well field and the VA Medical Center (VA) ATES well field, both located in Tuscaloosa, Alabama, and the Hanford bioremediation test site north of Richland, Washington

Tracer studies of flotation in the laboratory and in mineral processing plant

International Nuclear Information System (INIS)

Niemi, A.J.; Thereska, J.; Plasari, E.; Kacaj, M.

1993-01-01

Radioisotope tracers have a proven application for the extraction of residence time distributions and the evaluation of flotation rates in industry. This paper shows how values of the rate factor k are scaled up on the basis of flotation in the laboratory and tracer tests in plant. The procedure is illustrated by a theoretical study and by experimental data. The information obtained can be introduced into models of larger flotation systems. (author)

Bromide as a tracer for studying water movement and nitrate displacement in soils: comparison with stable isotope tracers

International Nuclear Information System (INIS)

Russow, R.; Knappe, S.

1999-01-01

Tracers are an ideal means of studying water movement and associated nitrate displacement. Often bromide is preferred as a tracer because it is considered a representative tracer for water and because, being a conservative tracer (i.e. not involved in chemical and biological soil processes), it can be used for studying anion transport in soils. Moreover, it is less expensive and easier to measure than the stable isotopes deuterium and 15 N. Its great advantage over radioactive tracers (e.g. tritium), which outweighs their extreme sensitivity and ease of measurement and which it has in common with stable isotopes, is that it does not require radiation protection measures. However, there are also constraints on the use of bromide as a tracer in soil/water/plant systems. Our own studies on different soils using D 2 O, bromide and [ 15 N]-nitrate in lysimeters suggest that the above assumptions on bromide tracers need not always be valid under conditions as they prevail in biologically active soils. As the present paper shows, these studies permit a good assessment of the possibilities and limits to these tracers [de

Natural tracer profiles across argillaceous formations

International Nuclear Information System (INIS)

Mazurek, Martin; Alt-Epping, Peter; Bath, Adrian; Gimmi, Thomas; Niklaus Waber, H.; Buschaert, Stephane; Canniere, Pierre De; Craen, Mieke De; Gautschi, Andreas; Savoye, Sebastien; Vinsot, Agnes; Wemaere, Isabelle; Wouters, Laurent

2011-01-01

Highlights: → Solute transport processes in clay and shale formations at nine sites are examined. → Conservative pore-water tracers (e.g. Cl - , δ 18 O, δ 2 H, He) show regular profiles. → These indicate the dominance of diffusive transport over times of 10 5 -10 6 years. → The contribution of vertical advection to transport is limited or negligible. → Modelled evolution times are in line with independent palaeo-hydrogeological data. - Abstract: Argillaceous formations generally act as aquitards because of their low hydraulic conductivities. This property, together with the large retention capacity of clays for cationic contaminants, has brought argillaceous formations into focus as potential host rocks for the geological disposal of radioactive and other waste. In several countries, programmes are under way to characterise the detailed transport properties of such formations at depth. In this context, the interpretation of profiles of natural tracers in pore waters across the formations can give valuable information about the large-scale and long-term transport behaviour of these formations. Here, tracer-profile data, obtained by various methods of pore-water extraction for nine sites in central Europe, are compiled. Data at each site comprise some or all of the conservative tracers: anions (Cl - , Br - ), water isotopes (δ 18 O, δ 2 H) and noble gases (mainly He). Based on a careful evaluation of the palaeo-hydrogeological evolution at each site, model scenarios are derived for initial and boundary pore-water compositions and an attempt is made to numerically reproduce the observed tracer distributions in a consistent way for all tracers and sites, using transport parameters derived from laboratory or in situ tests. The comprehensive results from this project have been reported in . Here the results for three sites are presented in detail, but the conclusions are based on model interpretations of the entire data set. In essentially all cases, the

Measurement of open streams by using tracers

International Nuclear Information System (INIS)

Ramos, German F.; Tarquino, W.; Curcuy, H.; Orozco, C.

1999-01-01

This paper presents an intercomparison study to be carried out between flux measurements by using tracers and moulinet. This intercomparison is scheduled to be performed at the measurement station belonging to the National Service of Meteorology and Hydrology (SENAMHI). Two techniques of tracer dilution are outstanded: total evaluation with tracer punctual injection and punctual evaluation with tracer continuous injection. Total evaluation with tracer punctual injection has been used since this technique is considered to be more suitable for hydrology purposes

Tracer attenuation in groundwater

Science.gov (United States)

Cvetkovic, Vladimir

2011-12-01

The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

Studies on the electrochemical behaviour of iron by the use of radio-tracer technique, 1. Studies on the electrodeposition and dissolution of iron by the use of radio-tracer technique

Energy Technology Data Exchange (ETDEWEB)

Moritani, Kimikazu; Ito, Yasuhiko; Kamata, Masahiro; Oishi, Jun

1984-12-01

To investigate whether radio-tracer techniques can augment conventional electrochemical techniques, offering useful information about the electrochemical behaviour of iron, the current efficiency of the electrodeposition of iron and the corrosion rate of metallic iron were measured by the radio-tracer method and the results were compared with the results measured by gravimetry and absorption photometry. Major conclusions obtained by the experiments are summarized as: 1) Between ordinary Fe and /sup 59/Fe, no isotope effect was observed. 2) Radiation from /sup 59/Fe had no effect on the electrode reaction. 3) While the use of a Ge semiconductor detector is undoubtedly preferable, Geiger-Mueller counter or NaI(Tl) scintillation counter gave fully satisfactory results. 4) Electrodeposited iron corrodes several times more rapidly than the iron base metal. These results suggests many other interesting applications of the radio-tracer technique when it is desired to obtain more detailed information on the electrochemical behaviour of iron. (author).

Coefficients of tracer transfer through membranes. Pt. 7

Energy Technology Data Exchange (ETDEWEB)

Dorabialska, A; Hawlicka, E; Plonka, A [Politechnika Lodzka (Poland)

1974-01-01

The doubled value of the tracer transfer coefficient in the self-diffusion process is equal to the sum of tracer transfer coefficients in the diffusion and interfusion processes. The fundamental phenomenological relation can be deduced for the coefficients of tracer transfer between two phases of electrolyte solutions spearated by a virtual boundary. Indeed, the doubled value of the tracer mobility in the self-diffusion experiment (no concentration gradient of the traced substance) is equal to the sum of the tracer mobilities in the diffusion (tracer movement along with the concentration gradient of the traced substance) and interfusion experiments (tracer movement against the concentration gradient of the traced substance). Thus the doubled value of the tracer transfer coefficient in the self-diffusion process should be equal to the sum of tracer transfer coefficients in the diffusion and interfusion processes. The experimental verification of that fundamental relation is presented.

Passive tracers in a general circulation model of the Southern Ocean

Directory of Open Access Journals (Sweden)

I. G. Stevens

Full Text Available Passive tracers are used in an off-line version of the United Kingdom Fine Resolution Antarctic Model (FRAM to highlight features of the circulation and provide information on the inter-ocean exchange of water masses. The use of passive tracers allows a picture to be built up of the deep circulation which is not readily apparent from examination of the velocity or density fields. Comparison of observations with FRAM results gives good agreement for many features of the Southern Ocean circulation. Tracer distributions are consistent with the concept of a global "conveyor belt" with a return path via the Agulhas retroflection region for the replenishment of North Atlantic Deep Water.

Key words. Oceanography: general (numerical modeling; water masses · Oceanography: physical (general circulation

Radioimmunoassay of bovine, ovine and porcine luteinizing hormone with a monoclonal antibody and a human tracer

Energy Technology Data Exchange (ETDEWEB)

Fosberg, M; Tagle, R; Madej, A; Molina, J R; Carlsson, M -A

1993-01-01

A radioimmunoassay for bovine (bLH), ovine (oLH) and porcine (pLH) luteinizing hormone was developed using a human [sup 125]ILH tracer from a commercial kit and a monoclonal antibody (518B7) specific for LH but with low species specificity. Standard curves demonstrated similar binding kinetics when bLH, oLH and pLH were incubated with tracer and antibody for 2 h at room temperature. A 30-min delay in the addition of the tracer gave sufficient sensitivity when analysing pLH. Separation of antibody-bound LH from free hormone was achieved by using second antibody-coated micro Sepharose beads. The assay was validated and the performance compared with that of an RIA currently in use for determination of bLH (coefficient of correlation: 0.99 and 0.98). Regardless of the standards used, intra-assay coefficients of variation were <10% for LH concentrations exceeding 1 [mu]g/L. The inter-assay coefficients of variation were <15%. The assay was used for clinical evaluation demonstrating the pre-ovulatory LH surge in two cyclic cows, LH pulsatility in an oophorectomized ewe and LH response to GnRH injection in a boar. (au) (7 refs.).

Evaluation of single- and dual-porosity models for reproducing the release of external and internal tracers from heterogeneous waste-rock piles.

Science.gov (United States)

Blackmore, S; Pedretti, D; Mayer, K U; Smith, L; Beckie, R D

2018-05-30

Accurate predictions of solute release from waste-rock piles (WRPs) are paramount for decision making in mining-related environmental processes. Tracers provide information that can be used to estimate effective transport parameters and understand mechanisms controlling the hydraulic and geochemical behavior of WRPs. It is shown that internal tracers (i.e. initially present) together with external (i.e. applied) tracers provide complementary and quantitative information to identify transport mechanisms. The analysis focuses on two experimental WRPs, Piles 4 and Pile 5 at the Antamina Mine site (Peru), where both an internal chloride tracer and externally applied bromide tracer were monitored in discharge over three years. The results suggest that external tracers provide insight into transport associated with relatively fast flow regions that are activated during higher-rate recharge events. In contrast, internal tracers provide insight into mechanisms controlling solutes release from lower-permeability zones within the piles. Rate-limited diffusive processes, which can be mimicked by nonlocal mass-transfer models, affect both internal and external tracers. The sensitivity of the mass-transfer parameters to heterogeneity is higher for external tracers than for internal tracers, as indicated by the different mean residence times characterizing the flow paths associated with each tracer. The joint use of internal and external tracers provides a more comprehensive understanding of the transport mechanisms in WRPs. In particular, the tracer tests support the notion that a multi-porosity conceptualization of WRPs is more adequate for capturing key mechanisms than a dual-porosity conceptualization. Copyright © 2018 Elsevier B.V. All rights reserved.

Halon-1301, a new Groundwater Age Tracer

Science.gov (United States)

Beyer, Monique; van der Raaij, Rob; Morgenstern, Uwe; Jackson, Bethanna

2015-04-01

Groundwater dating is an important tool to assess groundwater resources in regards to direction and time scale of groundwater flow and recharge and to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However ambiguous age interpretations are often faced, due to a limited set of available tracers and limitations of each tracer method when applied alone. There is a need for additional, complementary groundwater age tracers. We recently discovered that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate [Beyer et al, 2014]. Halon-1301 can be determined along with SF6, SF5CF3 and CFC-12 in groundwater using a gas chromatography setup with attached electron capture detector developed by Busenberg and Plummer [2008]. Halon-1301 has not been assessed in groundwater. This study assesses the behaviour of Halon-1301 in water and its suitability as a groundwater age tracer. We determined Halon-1301 in 17 groundwater and various modern (river) waters sites located in 3 different groundwater systems in the Wellington Region, New Zealand. These waters have been previously dated with tritium, CFC-12, CFC-11 and SF6 with mean residence times ranging from 0.5 to over 100 years. The waters range from oxic to anoxic and some show evidence of CFC contamination or degradation. This allows us to assess the different properties affecting the suitability of Halon-1301 as groundwater age tracer, such as its conservativeness in water and local contamination potential. The samples are analysed for Halon-1301 and SF6simultaneously, which allows identification of issues commonly faced when using gaseous tracers such as contamination with modern air during sampling. Overall we found in the assessed groundwater samples Halon-1301 is a feasible new groundwater tracer. No sample indicated significantly elevated

Innovative use of a microbial tracer for measuring groundwater through a fractured matrix

International Nuclear Information System (INIS)

Strong-Gunderson, J.M.

1995-01-01

Site characterization for ground water remediation activities is limited by the one's ability to visualize the complexity of the subsurface environment. Currently, a variety of dyes, colloids, gases, etc., are used to monitor and estimate ground water flow and contaminant transport. The author has recently identified a new, innovative colloidal tracer that is a non-hazardous bacterium that is detectable at very low concentrations (ng/kg), and can provide real-time analysis (3--5 min) for measuring colloid transport. The tracer is the ice nucleating active (INA) bacterium Pseudomonas syringae. The assay conditions require measuring the freezing point of the sample (e.g., ground water and soil slurries). Typically, 10--100 microL drops of water will not freeze until -15 to -20 C. However, if the tracer is present the water will freeze at -3 to -7 C. This increase in the freezing point can only be due to the presence of the tracer and this phenomenon is well documented in the plant pathology and low-temperature biology literature but has only now been applied to site characterization and remediation activities. Laboratory experiments have identified the stability of the tracer in the presence of a variety of ground water contaminants (> 100 ppm) and it is stable over a pH range of 2.3--10.0. The tracer has been demonstrated in conjunction with other commonly used tracers at a variety of field sites: (1) a drilling tracer to identify potential cross contamination, and as a colloid/bacterial tracer in (2) a hydrofracturing demonstration, (3) a horizontal recirculation well system, (4) a fractured karst matrix, and (5) a radioactive contaminated site. The data from these demonstrations have provided additional information about site characteristics including faster ground water flow rates than previously identified and due to its low sensitivities better distribution into a clay matrix than estimated by the bromide tracer

Semianalytical solutions of radioactive or reactive tracer transport in layered fractured media

International Nuclear Information System (INIS)

Moridis, G.J.; Bodvarsson, G.S.

2001-01-01

In this paper, semianalytical solutions are developed for the problem of transport of radioactive or reactive tracers (solutes or colloids) through a layered system of heterogeneous fractured media with misaligned fractures. The tracer transport equations in the matrix account for (a) diffusion, (b) surface diffusion (for solutes only), (c) mass transfer between the mobile and immobile water fractions, (d) linear kinetic or equilibrium physical, chemical, or combined solute sorption or colloid filtration, and (e) radioactive decay or first order chemical reactions. Any number of radioactive decay daughter products (or products of a linear, first-order reaction chain) can be tracked. The tracer-transport equations in the fractures account for the same processes, in addition to advection and hydrodynamic dispersion. Additionally, the colloid transport equations account for straining and velocity adjustments related to the colloidal size. The solutions, which are analytical in the Laplace space, are numerically inverted to provide the solution in time and can accommodate any number of fractured and/or porous layers. The solutions are verified using analytical solutions for limiting cases of solute and colloid transport through fractured and porous media. The effect of important parameters on the transport of 3 H, 237 Np and 239 Pu (and its daughters) is investigated in several test problems involving layered geological systems of varying complexity. 239 Pu colloid transport problems in multilayered systems indicate significant colloid accumulations at straining interfaces but much faster transport of the colloid than the corresponding strongly sorbing solute species

Systems identification: a theoretical method applied to tracer kinetics in aquatic microcosms

International Nuclear Information System (INIS)

Halfon, E.; Georgia Univ., Athens

1974-01-01

A mathematical model of radionuclide kinetics in a laboratory microcosm was built and the transfer parameters estimated by multiple regression and system identification techniques. Insight into the functioning of the system was obtained from analysis of the model. Methods employed have allowed movements of radioisotopes not directly observable in the experimental systems to be distinguished. Results are generalized to whole ecosystems

Wairakei tracer tests 1983

International Nuclear Information System (INIS)

McCabe, W.J.; Barry, B.J.

1984-05-01

Tracer tests, with and without, hot water reinjection into WK213 showed returns of tracer iodine-131; in wells in both the Waiora Valley and the eastern end of the field. The effect of reinjection at a rate of 200 cu. m/h was to reduce the arrived time from 15 to 7 days. Increasing the rate of reinjection into WK62 from 30 cu. m/h to 200 cu. m/h seemed to increase the initial velocity of the tracer wave and the distance it moved. However, returns were recorded only in the adjacent wells WK61 and WK63 with a very small, and three days delayed, response in WK43

Stable isotope labeled n-alkanes to assess digesta passage kinetics through the digestive tract of ruminants

NARCIS (Netherlands)

Warner, D.; Ferreira, L.M.M.; Breuer, M.J.H.; Dijkstra, J.; Pellikaan, W.F.

2013-01-01

We describe the use of carbon stable isotope (13C) labeled n-alkanes as a potential internal tracer to assess passage kinetics of ingested nutrients in ruminants. Plant cuticular n-alkanes originating from intrinsically 13C labeled ryegrass plants were pulse dosed intraruminally in four

Delineation and segmentation of cerebral tumors by mapping blood-brain barrier disruption with dynamic contrast-enhanced CT and tracer kinetics modeling-a feasibility study

International Nuclear Information System (INIS)

Bisdas, S.; Vogl, T.J.; Yang, X.; Koh, T.S.; Lim, C.C.T.

2008-01-01

Dynamic contrast-enhanced (DCE) imaging is a promising approach for in vivo assessment of tissue microcirculation. Twenty patients with clinical and routine computed tomography (CT) evidence of intracerebral neoplasm were examined with DCE-CT imaging. Using a distributed-parameter model for tracer kinetics modeling of DCE-CT data, voxel-level maps of cerebral blood flow (F), intravascular blood volume (v i ) and intravascular mean transit time (t 1 ) were generated. Permeability-surface area product (PS), extravascular extracellular blood volume (v e ) and extraction ratio (E) maps were also calculated to reveal pathologic locations of tracer extravasation, which are indicative of disruptions in the blood-brain barrier (BBB). All maps were visually assessed for quality of tumor delineation and measurement of tumor extent by two radiologists. Kappa (κ) coefficients and their 95% confidence intervals (CI) were calculated to determine the interobserver agreement for each DCE-CT map. There was a substantial agreement for the tumor delineation quality in the F, v e and t 1 maps. The agreement for the quality of the tumor delineation was excellent for the v i , PS and E maps. Concerning the measurement of tumor extent, excellent and nearly excellent agreement was achieved only for E and PS maps, respectively. According to these results, we performed a segmentation of the cerebral tumors on the base of the E maps. The interobserver agreement for the tumor extent quantification based on manual segmentation of tumor in the E maps vs. the computer-assisted segmentation was excellent (κ = 0.96, CI: 0.93-0.99). The interobserver agreement for the tumor extent quantification based on computer segmentation in the mean images and the E maps was substantial (κ = 0.52, CI: 0.42-0.59). This study illustrates the diagnostic usefulness of parametric maps associated with BBB disruption on a physiology-based approach and highlights the feasibility for automatic segmentation of

Statistically Based Morphodynamic Modeling of Tracer Slowdown

Science.gov (United States)

Borhani, S.; Ghasemi, A.; Hill, K. M.; Viparelli, E.

2017-12-01

Tracer particles are used to study bedload transport in gravel-bed rivers. One of the advantages associated with using of tracer particles is that they allow for direct measures of the entrainment rates and their size distributions. The main issue in large scale studies with tracer particles is the difference between tracer stone short term and long term behavior. This difference is due to the fact that particles undergo vertical mixing or move to less active locations such as bars or even floodplains. For these reasons the average virtual velocity of tracer particle decreases in time, i.e. the tracer slowdown. In summary, tracer slowdown can have a significant impact on the estimation of bedload transport rate or long term dispersal of contaminated sediment. The vast majority of the morphodynamic models that account for the non-uniformity of the bed material (tracer and not tracer, in this case) are based on a discrete description of the alluvial deposit. The deposit is divided in two different regions; the active layer and the substrate. The active layer is a thin layer in the topmost part of the deposit whose particles can interact with the bed material transport. The substrate is the part of the deposit below the active layer. Due to the discrete representation of the alluvial deposit, active layer models are not able to reproduce tracer slowdown. In this study we try to model the slowdown of tracer particles with the continuous Parker-Paola-Leclair morphodynamic framework. This continuous, i.e. not layer-based, framework is based on a stochastic description of the temporal variation of bed surface elevation, and of the elevation specific particle entrainment and deposition. Particle entrainment rates are computed as a function of the flow and sediment characteristics, while particle deposition is estimated with a step length formulation. Here we present one of the first implementation of the continuum framework at laboratory scale, its validation against

Oxygen tracer diffusion and surface exchange kinetics in Ba0.5Sr0.5Co0.8Fe0.2O3-δ

NARCIS (Netherlands)

Berenov, A.; Atkinson, A.; Kilner, J.; Ananyev, M.; Eremin, V.; Porotnikova, N.; Farlenkov, A.; Kurumchin, E.; Bouwmeester, Henricus J.M.; Bucher, E.; Sitte, W.

2014-01-01

The oxygen tracer diffusion coefficient, Db⁎, and the oxygen tracer surface exchange coefficient, k, were measured in Ba0.5Sr0.5Co0.8Fe0.2O3 − δ (BSCF5582) over the temperature range of 310–800 °C and the oxygen partial pressure range of 1.3 × 10−3–0.21 bar. Several measurement techniques were used:

Tracer research in process engineering

International Nuclear Information System (INIS)

Iller, E.

1992-01-01

The book is a review of modern applications of tracer techniques in chemical and process engineering studies. The next topics have been extensively presented: 1) media flow through apparatus; 2) the tracers in the study of media flow dynamics through apparatus; 3) mathematical interpretation of experimental data from impulse-response method; 4) the models of media flow through chemical reactors and apparatus; 5) radiotracers in mass transport study; 6) examples of practical applications of tracer methods in industrial objects. 84 refs, 96 figs, 31 tabs

Meteorological tracers in regional planning

International Nuclear Information System (INIS)

Mueller, K.H.

1974-11-01

Atmospheric tracers can be used as indicators to study both the ventilation of an urban region and its dispersion meteorology for air pollutants. A correlation analysis applied to the space-time dependent tracer concentrations is able to give transfer functions, the structure and characteristic parameters of which describe the meteorological and topographical situation of the urban region and its surroundings in an integral manner. To reduce the number of persons usually involved in a tracer experiment an automatic air sampling system had to be developed

New SPECT tracers: Example of tracers of proteoglycans and melanin

International Nuclear Information System (INIS)

Cachin, F.; Mestas, D.; Kelly, A.; Merlin, C.; Veyre, A.; Maublant, J.; Cachin, F.; Chezal, J.M.; Miot-Noirault, E.; Moins, N.; Auzeloux, P.; Vidal, A.; Bonnet-Duquennoy, M.; Boisgard, S.; D'Incan, M.; Madelmont, J.C.; Maublant, J.; Boisgard, S.; D'Incan, M.; Redini, F.; Filaire, M.

2009-01-01

The majority of research program on new radiopharmaceuticals turn to tracers used for positron emission tomography (PET). Only a few teams work on new non fluorine labeled tracers. However, the coming of SPECT/CT gamma cameras, the arrival of semi-conductors gamma cameras should boost the development of non-PET tracers. We exhibit in this article the experience acquired by our laboratory in the conception and design of two new non fluorine labelled compounds. The 99m Tc-N.T.P. 15-5 (N.T.P. 15-5 for N-[tri-ethyl-ammonium]-3-propyl-[15]ane-N5) which binds to proteoglycans could be used for the diagnosis and staging of osteoarthritis and chondrosarcoma. The iodo benzamides, specific to the melanin, are nowadays compared to 18 F-fluorodeoxyglucose in a phase III clinical trial for the diagnosis and detection of melanoma metastasis. Our last development focus on N-[2-(diethyl-amino)ethyl]-4 and 2-iodo benzamides respectively B.Z.A. and B.Z.A.2 hetero-aromatic analogues usable for melanoma treatment. (authors)

Interpretations of Tracer Tests Performed in the Culebra Dolomite at the Waste Isolation Pilot Plant Site

International Nuclear Information System (INIS)

MEIGS, LUCY C.; BEAUHEIM, RICHARD L.; JONES, TOYA L.

2000-01-01

This report provides (1) an overview of all tracer testing conducted in the Culebra Dolomite Member of the Rustler Formation at the Waste Isolation Pilot Plant (WPP) site, (2) a detailed description of the important information about the 1995-96 tracer tests and the current interpretations of the data, and (3) a summary of the knowledge gained to date through tracer testing in the Culebra. Tracer tests have been used to identify transport processes occurring within the Culebra and quantify relevant parameters for use in performance assessment of the WIPP. The data, especially those from the tests performed in 1995-96, provide valuable insight into transport processes within the Culebra. Interpretations of the tracer tests in combination with geologic information, hydraulic-test information, and laboratory studies have resulted in a greatly improved conceptual model of transport processes within the Culebra. At locations where the transmissivity of the Culebra is low ( -6 m 2 /s), we conceptualize the Culebra as a single-porosity medium in which advection occurs largely through the primary porosity of the dolomite matrix. At locations where the transmissivity of the Culebra is high (> 4 x 10 -6 m 2 /s), we conceptualize the Culebra as a heterogeneous, layered, fractured medium in which advection occurs largely through fractures and solutes diffuse between fractures and matrix at multiple rates. The variations in diffusion rate can be attributed to both variations in fracture spacing (or the spacing of advective pathways) and matrix heterogeneity. Flow and transport appear to be concentrated in the lower Culebra. At all locations, diffusion is the dominant transport process in the portions of the matrix that tracer does not access by flow

Radioactive tracers in the sea

International Nuclear Information System (INIS)

Jenkins, W.J.; Livingston, H.D.

1980-01-01

Artificial radionuclides introduced to the oceans during the last four decades have proved invaluable tools for study of many processes in marine water columns and sediments. Both global and close-in fallout of radioactivity from atmospheric nuclear weapons testing have distributed these radionuclides widely, and in amounts sufficient to be useful as tracers. An additional source of considerable significance and tracer potential comes from coastal discharges of European nuclear fuel reprocessing wastes. The nature of these sources, types and amounts of radionuclides introduced and the time histories of their introduction generate a variety of tracer distributions which illuminate a broad spectrum of physical and chemical processes active over a wide range of timescales. Depending on their respective chemistries, artificial radionuclides have been demonstrated to exhibit both conservative and non-conservative properties in the oceans. Some examples are given of the uses made of soluble, conservative tracers for the study of oceanic transport processes and of non-conservative tracers for studies of processes which move them to, and mix them within, marine sediments. Sampling and measurement techniques which have been used in these studies are described

Measuring SSRI occupancy of SERT using the novel tracer [123I]ADAM: a SPECT validation study

International Nuclear Information System (INIS)

Erlandsson, Kjell; Lui, Dominic; Townsend, Caroline E.; Ell, Peter J.; Sivananthan, Tharani; Mu, Song; Lucas, Richard; Spezzi, Andrea; Warrington, Steven

2005-01-01

Serotonergic brain regions play a crucial role in the modulation of emotion, and serotonergic dysfunction may contribute to several neurological disorders. [ 123 I]ADAM is a novel SPECT tracer which binds with high affinity to serotonin transporters (SERT). The objective of this study was to compare different methods for the quantification of tracer binding and to develop a simplified single-scan protocol for this tracer, as well as to investigate its potential for characterisation of the transporter occupancy versus plasma concentration curve of a selective serotonin re-uptake inhibitor (SSRI). Dynamic SPECT scans were performed on 16 healthy volunteers after administration of ∝150 MBq [ 123 I]ADAM. Data were acquired from the time of injection until ∝5.5 h after injection in 30- or 45-min sessions. Each subject was scanned twice: with and without pre-treatment with the SSRI citalopram in various dosage regimens. The plasma concentration of citalopram (C p ) was determined from venous samples. Images were reconstructed by filtered back-projection with scatter and attenuation correction. Tracer binding was quantified for midbrain, striatum and thalamus using cerebellum as a reference region. Quantification was done by kinetic modelling, graphical analysis and multi-linear regression, as well as by the ratio method, with binding potential (BP 2 ) as the outcome measure. The SERT occupancy by citalopram was determined relative to the baseline scan for each subject, and the occupancy versus C p curve was fitted with the E max model. The highest binding of [ 123 I]ADAM was in midbrain (mean baseline BP 2 ±SD=1.31±0.29), with lower binding in thalamus (0.79±0.16) and striatum (0.66±0.13). There was good agreement between BP 2 values obtained by different quantification methods. Using the ratio method, the best agreement with kinetic modelling was obtained with data from the time interval [200,260] min after injection. The fitting of the midbrain occupancy curve

Tracer filamentation at an unstable ocean front

Science.gov (United States)

Feng, Yen Chia; Mahadevan, Amala; Thiffeault, Jean-Luc; Yecko, Philip

2017-11-01

A front, where two bodies of ocean water with different physical properties meet, can become unstable and lead to a flow with high strain rate and vorticity. Phytoplankton and other oceanic tracers are stirred into filaments by such flow fields, as can often be seen in satellite imagery. The stretching and folding of a tracer by a two-dimensional flow field has been well studied. In the ocean, however, the vertical shear of horizontal velocity is typically two orders of magnitude larger than the horizontal velocity gradient. Theoretical calculations show that vertical shear alters the way in which horizontal strain affects the tracer, resulting in thin, sloping structures in the tracer field. Using a non-hydrostatic ocean model of an unstable ocean front, we simulate tracer filamentation to identify the effect of vertical shear on the deformation of the tracer. In a complementary laboratory experiment, we generate a simple, vertically sheared strain flow and use dye and particle image velocimetry to quantify the filamentary structures in terms of the strain and shear. We identify how vertical shear alters the tracer filaments and infer how the evolution of tracers in the ocean will differ from the idealized two-dimensional paradigm. Support of NSF DMS-1418956 is acknowledged.

Tracer dispersion - experiment and CFD

International Nuclear Information System (INIS)

Zitny, R.

2004-01-01

Description of tracer distribution by means of dispersion models is a method successfully used in process engineering for fifty years. Application of dispersion models in reactor engineering for characterization of flows in column apparatus, heat exchangers, etc. is summarized and experimental tracer techniques as well as CFD methods for dispersion coefficients evaluation are discussed. Possible extensions of thermal axial dispersion model (ADM) and a core-wall ADM model suitable for description of tracer dispersion in laminar flows are suggested as well as CFD implementation as 1D finite elements. (author)

Preparation of mono-radioiodinated tracers for study of the in vivo metabolism of atrial natriuretic peptide in humans

International Nuclear Information System (INIS)

Clerico, A.; Marastoni, M.; Del Chicca, M.G.; Giannessi, D.; Del Ry, S.; Andreassi, M.G.; Sabatino, L.; Iascone, M.R.; Biagini, A.; Donato, L.

1995-01-01

The authors evaluate the optimum chemical conditions for labelling atrial natriuretic peptide (ANP) and its metabolites and for preparing highly purified radiotracers which can be used for in vivo kinetic studies of ANP in humans. Synthetic α h 1-28 ANP and some hormone metabolites were iodinated with Na 125 I or Na 131 I by means of the lactoperoxidase (ANP) or the chloramine-T (ANP metabolites) technique. The biological activity of labelled ANP was tested by means of a binding study using mouse cardiac membranes. A high-performance liquid chromatography (HPLC) procedure was used to purify the labelled hormone and the principal labelled metabolites in venous plasma samples collected up to 50 min after the injection of 125 I-labelled ANP from nine healthy men. The main ANP kinetic parameters were derived from the disappearance curves of the [ 125 I]ANP, which were satisfactorily fitted by a bi-exponential function in all subjects. The main advantages of this tracer technique are high accuracy, allowing the identification of the metabolites produced in vivo under steady-state conditions after injection of the precursor (labelled hormone) high sensitivity, allowing the detection of minimal quantities of metabolites high specificity, allowing the detection of possible in vitro artefactual generation of cleavage products of ANP using an internal labelled standard. Utilizing this tracer method, it was possible to estimate the principal parameters of ANP kinetics and also to plot the appearance curves of the labelled metabolites produced in vivo after the injection of the labelled precursor. (orig.). With 5 figs

Diagnostic information of TL-201 myocardial kinetics shortly after termination of exercise

International Nuclear Information System (INIS)

Wackers, F.J.; Fetterman, R.C.; Heitzman, M.; Clements, J.

1984-01-01

Traditionally, T1-201 stress imaging is performed immediately post exercise (EX) and 2-4 hrs later. This interval was chosen initially for visual comparison of T1-201 images and more recently for assessment of T1-201 washout (WO). Previously, the authors demonstrated that T1-201 kinetics shortly after EX are variable in patients (pts) with coronary artery disease (CAD). In this study, the authors evaluated the potential diagnostic information to be gained from analysis of early post EX T1-201 kinetics. In 70 pts, quantitative T1-201 stress imaging was performed. Sixteen pts were normal, 54 pts had CAD by angiography. All pts had symptom-limited EX. Serial LAO imaging was performed: 1) 5 min post EX; 2) 30 min post EX; 3) 2 hrs post EX. After interpolative background correction, circumferential WO profiles were generated. All normals had WO of T1-201 at 30 min post EX (average WO 14%). In contrast, 21 (39%) of pts with CAD had accumulation of T1-201, 5 (9%) had no change and 28 (52%) had WO at 30 min post EX. Between 30 min and 2 hrs post EX, 50 of 54 (93%) pts with CAD had WO. At 2 hrs, compared to 5 min post EX, 39 (72%) of pts with CAD had abnormal low WO (<30%) including all 21 with initial accumulation and 3 of 5 with initially no change of T1-201. Thus, whereas at 2 hrs post EX 72% of pts with CAD are abnormal by degree of WO, at 30 min post EX 48% are abnormal by direction of T1-201 kinetics. Continued increase of T1-201 at 30 min post EX is highly specific for CAD, although less sensitive than abnormal WO at 2 hrs post EX. Nevertheless, T1-201 kinetics shortly post EX contribute useful diagnostic information that may enhance reliability and confidence in interpretation of quantitative T1-201 analysis

Thermodynamics and kinetics of interstitial diffusion in a two-component system

International Nuclear Information System (INIS)

McKee, R.A.

1980-01-01

Diffusion theory is developed for a two-component system in which only the interstitial element is mobile. A thermodynamic formalism is used in direct parallel with a kinetic theory to construct a mechanism-independent relationship between tracer- and chemical-diffusion coefficients. It is found that D/sup I/=(D-italic*/f)(1+partiallnγ/partiallnC). D/sup I/ is the intrinsic- or chemical-diffusion coefficient for the interstitial, D* is the tracer-diffusion coefficient, f is the correlation factor, and γ is the activity coefficient. This expression accounts for site exclusion, correlation, and drift effects that occur as the interstitial content changes. Generalized phenomenological coefficients that are determined in this analysis can be used for standard representations of diffusion in electric fields and temperature gradients. Moreover, the forms that the phenomenological coefficients take for the interstitial system are the same as those previously derived for vacancy diffusion. A test of this predicted relationship between tracer- and chemical-diffusion coefficients is developed using a comparison between theory and experiment for carbon diffusion in fcc iron

General circulation and tracers: studies in the Western Indian Ocean

International Nuclear Information System (INIS)

Jamous, Daniel

1991-01-01

The main question addressed in this thesis is how to best use the information obtained from hydro-biogeochemical tracer data, to study the oceanic general circulation in the Western Indian Ocean. First, a principal component analysis is performed on a historical data set. The tracers considered are temperature, salinity, density, oxygen, phosphate and silica. The method reduces the amount of data to be considered by a factor of 5. It reproduces correctly and efficiently the large-scale distributions of these oceanic properties. The analysed data are then used in a finite-difference nonlinear inverse model. The grid has a resolution of 4 deg. by 4 deg.. Dynamical as well as tracer conservation constraints are used. These constraints are well satisfied by the obtained solutions but the associated errors remain large. Additional constraints would be required in order to discuss the different solutions in more detail. Finally, a qualitative study is done on the deep distribution of helium-3. The data show several important features linked to hydrothermal input in the Gulf of Aden and on the Central Indian Ridge, and to the origin of water masses and deep circulation characteristics. However additional data are required in order to clarify the distribution of this tracer in other key areas. (author) [fr

Joint interpretation of two tracer tests with reversed flow fields

International Nuclear Information System (INIS)

Kunstmann, H.; Kinzelbach, W.; Marschall, P.; Li, G.

1995-01-01

Two dipole tracer experiments were performed in a fractured rock at the Grimsel Test Site in February/March 1993. In both experiments NaCl was used as a tracer. The extraction rate was twice the injection rate. In the second experiment injection and extraction were interchanged (Reverse-Experiment). Long tailing was characteristic for the breakthrough curves in both experiments. The tests were interpreted using a single fracture flow model. Tracer transport is described by advection/dispersion along the fracture allowing for diffusion into an immobile matrix. The authors were able to interpret the breakthrough curves for both experiments by one unique set of parameters, describing transport and baseflow. Uniqueness could only be achieved when using the information of both experiments. The authors conclude that performing a Reverse-Experiment is an indispensable tool for parameter identification in dipole tracer tests. A sensitivity analysis suggested that not only matrix diffusion is responsible for the tailing in the breakthrough curves but also transversal dispersivity. Further, the typical exchange time between mobile and immobile media was too small to be attributed to matrix diffusion in the strict sense which will cause tailing even at large spatial and temporal scales. Analysis of the covariance matrices showed that the parameters have small errors but high correlation

Role of tracer methods in hydrology as a source of physical information. Basic concepts and definitions. Time relationship in dynamic systems

International Nuclear Information System (INIS)

Nir, A.

1986-01-01

The paper provides a general review on the systems theory approach for the tracer methodology, indicating also the relations of the system theory to other available approaches such as deterministic mechanism description and stochastic approaches. Methodology and formulations of systems approach as applied to tracer use in steady-state cases are discussed. Extension of the systems approach for tracer use in non-steady-state cases and input-output relationships for time varying systems are also given. (author)

Tracer techniques in microelectronics

International Nuclear Information System (INIS)

Flachowsky, J.; Freyer, K.

1981-01-01

Tracer technique and neutron activation analysis are capable of measuring impurities in semiconductor material or on the semiconductor surface in a very low concentration range. The methods, combined with autoradiography, are also suitable to determine dopant distributions in silicon. However, both techniques suffer from certain inherent experimental difficulties and/or limitations which are discussed. Methods of tracer technique practicable in the semiconductor field are described. (author)

β-methyl-15-p-iodophenylpentadecanoic acid metabolism and kinetics in the isolated rat heart

International Nuclear Information System (INIS)

DeGrado, T.R.; Holden, J.E.; Ng, C.K.; Raffel, D.M.; Gatley, S.J.

1989-01-01

The use of 15-p-iodophenyl-β-methyl-pentadecanoic acid (βMe-IPPA) as an indicator of long chain fatty acid (LCFA) utilization in nuclear medicine studies was evaluated in the isolated, perfused, working rat heart. Time courses of radioactivity (residue curves) were obtained following bolus injections of both βMe-IPPA and its straight chain counterpart 15-p-iodophenyl-pentadecanoic acid (IPPA). IPPA kinetics clearly indicated flow independent impairment of fatty acid oxidation caused by the carnitine palmitoyltransferase I inhibitor 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). In contrast, βMe-IPPA kinetics were insensitive to changes in fatty acid oxidation rate and net utilization of long chain fatty acid. Analysis of radiolabeled species in coronary effluent and heart homogenates showed the methylated fatty acid to be readily incorporated into complex lipids but a poor substrate for oxidation. POCA did not significantly alter metabolism of the tracer, suggesting that the tracer is poorly metabolized beyond βMe-IPPA-CoA in the oxidative pathway. (orig.)

Tracer transport in fractured rocks

International Nuclear Information System (INIS)

Tsang, C.F.; Tsang, Y.W.; Hale, F.V.

1988-07-01

Recent interest in the safety of toxic waste underground disposal and nuclear waste geologic repositories has motivated many studies of tracer transport in fractured media. Fractures occur in most geologic formations and introduce a high degree of heterogeneity. Within each fracture, the aperture is not constant in value but strongly varying. Thus for such media, tracer tends to flow through preferred flowpaths or channels within the fractures. Along each of these channels, the aperture is also strongly varying. A detailed analysis is carried out on a 2D single fracture with variable apertures and the flow through channels is demonstrated. The channels defined this way are not rigidly set pathways for tracer transport, but are the preferred flow paths in the sense of stream-tubes in the potential theory. It is shown that such variable-aperture channels can be characterized by an aperture probability distribution function, and not by the exact deterministic geometric locations. We also demonstrate that the 2D tracer transport in a fracture can be calculated by a model of a system of 1D channels characterized by this distribution function only. Due to the channeling character of tracer transport in fractured rock, random point measurements of tracer breakthrough curves may give results with a wide spread in value due to statistical fluctuations. The present paper suggests that such a wide spread can probably be greatly reduced by making line/areal (or multiple) measurements covering a few spatial correlation lengths. 13 refs., 11 figs., 1 tab

Tracers of air-sea gas exchange

International Nuclear Information System (INIS)

Liss, P.S.

1988-01-01

The flux of gas across the air-sea interface is determined by the product of the interfacial concentration difference driving the exchange and a rate constant, often termed the transfer velocity. The concentration-difference term is generally obtained by direct measurement, whereas more indirect approaches are required to estimate the transfer velocity and its variation as a function of controlling parameters such as wind and sea state. Radioactive tracers have proved particularly useful in the estimation of air-sea transfer velocities and, recently, stable purposeful tracers have also started to be used. In this paper the use of the following tracers to determine transfer velocities at the sea surface is discussed: natural and bomb-produced 14 C, dissolved oxygen, 222 Rn and sulphur hexafluoride. Other topics covered include the relation between transfer velocity and wind speed as deduced from tracer and wind-tunnel studies, and the discrepancy between transfer velocities determined by using tracers and from eddy correlation measurements in the atmosphere. (author)

First technical report about tracer applications to processes assessment in a portable water potabilizing plant; Primer informe de avance sobre ensayos con uranina de una Planta Potabilizadora Portatil de OSE

Energy Technology Data Exchange (ETDEWEB)

Suarez Antola, R; Giosa Porley, P

1996-03-15

Radioactive and fluorescent tracers were applied to measure the distribution of residence times in each of the four subsystems of a portable water purifying plant: the mechanical flocculation unit, the hydraulic flocculation unit, the sedimentation unit, and the sand filter. This report begins by a revision of the physicochemical processes produced in each of the above mentioned subsystems, connected in series. Then a mathematical model of residence time distribution for each unit is constructed, with free parameters that can be estimated from the experimental results obtained with tracers. Tracer methodology for this kind of field experiment is reviewed. Their possible short comes are briefly discussed for each of the intended tracers. The tracer experiments done with rhodamine and uranine are described. The experimental results are reported and the residence time distributions obtained with different tracers were carefully compared. In order to make the field experiments, five different values of global water flow were sustained, pumping in steady state: two under the nominal (design) value, two above the design flow and one equal to the nominal water flow. The model parameters were determined using a software package, {sup D}TR{sup ,} made in France and supplied by the IAEA in the framework of the project. It was discovered that the diffuser in the sedimentation unit was not working as intended, and some guidelines for its re-design could be given to the process engineers. Also, process engineers received information about some amount of by-pass flow and death zones, as well as their variations with plant's global water flow.

Interpretations of Tracer Tests Performed in the Culebra Dolomite at the Waste Isolation Pilot Plant Site

Energy Technology Data Exchange (ETDEWEB)

MEIGS,LUCY C.; BEAUHEIM,RICHARD L.; JONES,TOYA L.

2000-08-01

This report provides (1) an overview of all tracer testing conducted in the Culebra Dolomite Member of the Rustler Formation at the Waste Isolation Pilot Plant (WPP) site, (2) a detailed description of the important information about the 1995-96 tracer tests and the current interpretations of the data, and (3) a summary of the knowledge gained to date through tracer testing in the Culebra. Tracer tests have been used to identify transport processes occurring within the Culebra and quantify relevant parameters for use in performance assessment of the WIPP. The data, especially those from the tests performed in 1995-96, provide valuable insight into transport processes within the Culebra. Interpretations of the tracer tests in combination with geologic information, hydraulic-test information, and laboratory studies have resulted in a greatly improved conceptual model of transport processes within the Culebra. At locations where the transmissivity of the Culebra is low (< 4 x 10{sup -6} m{sup 2}/s), we conceptualize the Culebra as a single-porosity medium in which advection occurs largely through the primary porosity of the dolomite matrix. At locations where the transmissivity of the Culebra is high (> 4 x 10{sup -6} m{sup 2}/s), we conceptualize the Culebra as a heterogeneous, layered, fractured medium in which advection occurs largely through fractures and solutes diffuse between fractures and matrix at multiple rates. The variations in diffusion rate can be attributed to both variations in fracture spacing (or the spacing of advective pathways) and matrix heterogeneity. Flow and transport appear to be concentrated in the lower Culebra. At all locations, diffusion is the dominant transport process in the portions of the matrix that tracer does not access by flow.

Radioactive tracer technique in process optimization: applications in the chemical industry

International Nuclear Information System (INIS)

Charlton, J.S.

1989-01-01

Process optimization is concerned with the selection of the most appropriate technological design of the process and with controlling its operation to obtain maximum benefit. The role of radioactive tracers in process optimization is discussed and the various circumstances under which such techniques may be beneficially applied are identified. Case studies are presented which illustrate how radioisotopes may be used to monitor plant performance under dynamic conditions to improve production efficiency and to investigate the cause of production limitations. In addition, the use of sealed sources to provide information complementary to the tracer study is described. (author)

How to Program a Domain Independent Tracer for Explanations

Science.gov (United States)

Ishizaka, Alessio; Lusti, Markus

2006-01-01

Explanations are essential in the teaching process. Tracers are one possibility to provide students with explanations in an intelligent tutoring system. Their development can be divided into four steps: (a) the definition of the trace model; (b) the extraction of the information from this model; (c) the analysis and abstraction of the extracted…

Measuring SSRI occupancy of SERT using the novel tracer [{sup 123}I]ADAM: a SPECT validation study

Energy Technology Data Exchange (ETDEWEB)

Erlandsson, Kjell; Lui, Dominic; Townsend, Caroline E.; Ell, Peter J. [Middlesex Hospital, Institute of Nuclear Medicine, University College London, London (United Kingdom); Sivananthan, Tharani; Mu, Song; Lucas, Richard [Lilly Research Centre, Eli Lilly and Company, Windlesham, Surrey (United Kingdom); Spezzi, Andrea; Warrington, Steven [Central Middlesex Hospital, Hammersmith Medicines Research, London (United Kingdom)

2005-11-01

Serotonergic brain regions play a crucial role in the modulation of emotion, and serotonergic dysfunction may contribute to several neurological disorders. [{sup 123}I]ADAM is a novel SPECT tracer which binds with high affinity to serotonin transporters (SERT). The objective of this study was to compare different methods for the quantification of tracer binding and to develop a simplified single-scan protocol for this tracer, as well as to investigate its potential for characterisation of the transporter occupancy versus plasma concentration curve of a selective serotonin re-uptake inhibitor (SSRI). Dynamic SPECT scans were performed on 16 healthy volunteers after administration of {proportional_to}150 MBq [{sup 123}I]ADAM. Data were acquired from the time of injection until {proportional_to}5.5 h after injection in 30- or 45-min sessions. Each subject was scanned twice: with and without pre-treatment with the SSRI citalopram in various dosage regimens. The plasma concentration of citalopram (C{sub p}) was determined from venous samples. Images were reconstructed by filtered back-projection with scatter and attenuation correction. Tracer binding was quantified for midbrain, striatum and thalamus using cerebellum as a reference region. Quantification was done by kinetic modelling, graphical analysis and multi-linear regression, as well as by the ratio method, with binding potential (BP{sub 2}) as the outcome measure. The SERT occupancy by citalopram was determined relative to the baseline scan for each subject, and the occupancy versus C{sub p} curve was fitted with the E{sub max} model. The highest binding of [{sup 123}I]ADAM was in midbrain (mean baseline BP{sub 2}{+-}SD=1.31{+-}0.29), with lower binding in thalamus (0.79{+-}0.16) and striatum (0.66{+-}0.13). There was good agreement between BP{sub 2} values obtained by different quantification methods. Using the ratio method, the best agreement with kinetic modelling was obtained with data from the time interval

Determination of regional flow by use of intravascular PET tracers: microvascular theory and experimental validation for pig livers

DEFF Research Database (Denmark)

Munk, O L; Bass, L; Feng, H

2003-01-01

Today, the standard approach for the kinetic analysis of dynamic PET studies is compartment models, in which the tracer and its metabolites are confined to a few well-mixed compartments. We examine whether the standard model is suitable for modern PET data or whether theories including more...... physiologic realism can advance the interpretation of dynamic PET data. A more detailed microvascular theory is developed for intravascular tracers in single-capillary and multiple-capillary systems. The microvascular models, which account for concentration gradients in capillaries, are validated and compared...... with the standard model in a pig liver study. METHODS: Eight pigs underwent a 5-min dynamic PET study after (15)O-carbon monoxide inhalation. Throughout each experiment, hepatic arterial blood and portal venous blood were sampled, and flow was measured with transit-time flow meters. The hepatic dual...

Doublet Tracer Testing in Klamath Falls, Oregon

Energy Technology Data Exchange (ETDEWEB)

Gudmundsson, J S; Johnson, S E; Horne, R N; Jackson, P B [Pet. Eng. Dept., Stanford University; Culver, G G [Geo-Heat Center, Oregon Institute of Technology, Klamath Falls, OR

0000-12-30

A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 degrees Fahrenheit water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.

Tracer a application in marine outfall studies

International Nuclear Information System (INIS)

Genders, S.

1979-01-01

The applicability of radioactive and fluorescent tracers for field studies to predict or investigate waste water transport and dispersion from marine outfalls is evaluated. The application of either instantaneous or continuous tracer release, 'in situ' detection of tracers and data processing are considered. The necessity of a combined use of tracer techniques and conventional hydrographic methods for a statistical prediction of transport and dillution of waste water are pointed out. A procedure to determine an outlet distance from the coast, which satisfy bathing water criteria is outlined. (M.A.) [pt

Doublet Tracer Testing in Klamath Falls, Oregon

Energy Technology Data Exchange (ETDEWEB)

Gudmundsson, J.S.; Johnson, S.E.; Horne, R.N.; Jackson, P. B. [Pet. Eng. Dept., Stanford University; Culver, G.G. [Geo-Heat Center, Oregon Institute of Technology, Klamath Falls, OR

0001-01-01

A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 degrees Fahrenheit water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.

Water renewal in Montevideo's bay: a two compartments model for tritium kinetics

International Nuclear Information System (INIS)

Suarez-Antola, Roberto

2013-01-01

During field work about dynamics and renewal of water in Montevideo's Bay, 100 Ci of tritiated water were evenly distributed in the north-east region of the bay, by a continuous injection of a solution, during 5 hours, from a 200 litres tank, using a peristaltic pump. The whole bay was divided in 20 concentration cells, taking into account available bathymetric charts and corrections from field data obtained in situ. Tritium concentrations (activities per unit volume) and other relevant parameters (temperature, electrical conductivity, etc.) were measured in vertical profiles during three weeks, in the mid-point of each cell, first twice a day and the on a daily basis. Remnant total tritium activity was estimated from cells volumes and midpoint cells activity concentrations. Consistency checks were done. A one compartment model was used to estimate a global renewal time of circa 29 hours. However, the details of the measured tritium kinetics, a careful consideration of bathymetric data, water movements in a tidal environment (measured with drogues, fluorescent tracers and current meters), as well as the results of computer fluid dynamics modelling (in depth averaged) suggests that the bay can be meaningfully divided in two main compartments: a North-East and a South-West compartment. The purpose of this paper is threefold: (1) to describe the construction of a two compartments model for water renewal in Montevideo's Bay, (2) to apply experimental data of tritium kinetics to estimate the parameters of the model, and (3) to discuss the validity of the model and its practical applicability. The meaning of the renewal time of each compartment and its relation with the measured tritium kinetics in each cell is discussed. The perturbations in water circulation and renewal produced by civil works already done or the perturbations that could be expected due to civil works to be done, in relation with Montevideo's harbour, is discussed. The tracer model, jointly with other

Bromide as a tracer for studying water movement and nitrate displacement in soils: comparison with stable isotope tracers; Bromid als Tracer zur Untersuchung der Wasserbewegung und der Nitratverlagerung in Boeden: Vergleich mit stabilisotopen Tracern

Energy Technology Data Exchange (ETDEWEB)

Russow, R.; Knappe, S. [UFZ - Umweltforschungszentrum Leipzig-Halle GmbH, Bad Lauchstaedt (Germany). Sektion Bodenforschung

1999-02-01

Tracers are an ideal means of studying water movement and associated nitrate displacement. Often bromide is preferred as a tracer because it is considered a representative tracer for water and because, being a conservative tracer (i.e. not involved in chemical and biological soil processes), it can be used for studying anion transport in soils. Moreover, it is less expensive and easier to measure than the stable isotopes deuterium and {sup 15}N. Its great advantage over radioactive tracers (e.g. tritium), which outweighs their extreme sensitivity and ease of measurement and which it has in common with stable isotopes, is that it does not require radiation protection measures. However, there are also constraints on the use of bromide as a tracer in soil/water/plant systems. Our own studies on different soils using D{sub 2}O, bromide and [{sup 15}N]-nitrate in lysimeters suggest that the above assumptions on bromide tracers need not always be valid under conditions as they prevail in biologically active soils. As the present paper shows, these studies permit a good assessment of the possibilities and limits to these tracers. [Deutsch] Fuer die Untersuchung der Wasserbewegung sowie der daran gekoppelten Nitrat-Verlagerung ist der Einsatz von Tracern das Mittel der Wahl. Dabei wird Bromid als Tracer haeufig bevorzugt, da es allgemein als ein repraesentativer Tracer fuer Wasser und als konservativer Tracer (nicht involviert in chemische und biologische Bodenprozesse) zur Untersuchung des Anionentransportes in Boeden angesehen wird und es gegenueber den stabilen Isotopen Deuterium und {sup 15}N billiger und einfacher zu bestimmen ist. Gegenueber den radioaktiven Tracern (z.B. Tritium), die zwar sehr empfindlich und einfach messbar sind, besteht der grosse Vorteil, dass, wie bei den stabilen Isotopen, keine Strahlenschutzmassnahmen ergriffen werden muessen. Es gibt jedoch auch einschraenkende Hinweise fuer die Verwendung von Bromid als Tracer im System Boden

Doublet tracer tests to determine the contaminant flushing properties of a municipal solid waste landfill.

Science.gov (United States)

Woodman, N D; Rees-White, T C; Beaven, R P; Stringfellow, A M; Barker, J A

2017-08-01

This paper describes a programme of research investigating horizontal fluid flow and solute transport through saturated municipal solid waste (MSW) landfill. The purpose is to inform engineering strategies for future contaminant flushing. Solute transport between injection/abstraction well pairs (doublets) is investigated using three tracers over five separate tests at well separations between 5m and 20m. Two inorganic tracers (lithium and bromide) were used, plus the fluorescent dye tracer, rhodamine-WT. There was no evidence for persistent preferential horizons or pathways at the inter-well scale. The time for tracer movement to the abstraction wells varied with well spacing as predicted for a homogeneous isotropic continuum. The time for tracer movement to remote observation wells was also as expected. Mobile porosity was estimated as ~0.02 (~4% of total porosity). Good fits to the tracer breakthrough data were achieved using a dual-porosity model, with immobile regions characterised by block diffusion timescales in the range of about one to ten years. This implies that diffusional exchanges are likely to be very significant for engineering of whole-site contaminant flushing and possibly rate-limiting. Copyright © 2017. Published by Elsevier B.V.

INTRAVAL Finnsjoen Test - modelling results for some tracer experiments

International Nuclear Information System (INIS)

Jakob, A.; Hadermann, J.

1994-09-01

This report presents the results within Phase II of the INTRAVAL study. Migration experiments performed at the Finnsjoen test site were investigated. The study was done to gain an improved understanding of not only the mechanisms of tracer transport, but also the accuracy and limitations of the model used. The model is based on the concept of a dual porosity medium, taking into account one dimensional advection, longitudinal dispersion, sorption onto the fracture surfaces, diffusion into connected pores of the matrix rock, and sorption onto matrix surfaces. The number of independent water carrying zones, represented either as planar fractures or tubelike veins, may be greater than one, and the sorption processes are described either by linear or non-linear Freundlich isotherms assuming instantaneous sorption equilibrium. The diffusion of the tracer out of the water-carrying zones into connected pore space of the adjacent rock is calculated perpendicular to the direction of the advective/dispersive flow. In the analysis, the fluid flow parameters are calibrated by the measured breakthrough curves for the conservative tracer (iodide). Subsequent fits to the experimental data for the two sorbing tracers strontium and cesium then involve element dependent parameters providing information on the sorption processes and on its representation in the model. The methodology of fixing all parameters except those for sorption with breakthrough curves for non-sorbing tracers generally worked well. The investigation clearly demonstrates the necessity of taking into account pump flow rate variations at both boundaries. If this is not done, reliable conclusions on transport mechanisms or geometrical factors can not be achieved. A two flow path model reproduces the measured data much better than a single flow path concept. (author) figs., tabs., 26 refs

Amyloid-β Plaques in Clinical Alzheimer’s Disease Brain Incorporate Stable Isotope Tracer In Vivo and Exhibit Nanoscale Heterogeneity

Science.gov (United States)

Wildburger, Norelle C.; Gyngard, Frank; Guillermier, Christelle; Patterson, Bruce W.; Elbert, Donald; Mawuenyega, Kwasi G.; Schneider, Theresa; Green, Karen; Roth, Robyn; Schmidt, Robert E.; Cairns, Nigel J.; Benzinger, Tammie L. S.; Steinhauser, Matthew L.; Bateman, Randall J.

2018-01-01

Alzheimer’s disease (AD) is a neurodegenerative disorder with clinical manifestations of progressive memory decline and loss of executive function and language. AD affects an estimated 5.3 million Americans alone and is the most common form of age-related dementia with a rapidly growing prevalence among the aging population—those 65 years of age or older. AD is characterized by accumulation of aggregated amyloid-beta (Aβ) in the brain, which leads to one of the pathological hallmarks of AD—Aβ plaques. As a result, Aβ plaques have been extensively studied after being first described over a century ago. Advances in brain imaging and quantitative measures of Aβ in biological fluids have yielded insight into the time course of plaque development decades before and after AD symptom onset. However, despite the fundamental role of Aβ plaques in AD, in vivo measures of individual plaque growth, growth distribution, and dynamics are still lacking. To address this question, we combined stable isotope labeling kinetics (SILK) and nanoscale secondary ion mass spectrometry (NanoSIMS) imaging in an approach termed SILK–SIMS to resolve plaque dynamics in three human AD brains. In human AD brain, plaques exhibit incorporation of a stable isotope tracer. Tracer enrichment was highly variable between plaques and the spatial distribution asymmetric with both quiescent and active nanometer sub-regions of tracer incorporation. These data reveal that Aβ plaques are dynamic structures with deposition rates over days indicating a highly active process. Here, we report the first, direct quantitative measures of in vivo deposition into plaques in human AD brain. Our SILK–SIMS studies will provide invaluable information on plaque dynamics in the normal and diseased brain and offer many new avenues for investigation into pathological mechanisms of the disease, with implications for therapeutic development. PMID:29623063

Amyloid-β Plaques in Clinical Alzheimer’s Disease Brain Incorporate Stable Isotope Tracer In Vivo and Exhibit Nanoscale Heterogeneity

Directory of Open Access Journals (Sweden)

Norelle C. Wildburger

2018-03-01

Full Text Available Alzheimer’s disease (AD is a neurodegenerative disorder with clinical manifestations of progressive memory decline and loss of executive function and language. AD affects an estimated 5.3 million Americans alone and is the most common form of age-related dementia with a rapidly growing prevalence among the aging population—those 65 years of age or older. AD is characterized by accumulation of aggregated amyloid-beta (Aβ in the brain, which leads to one of the pathological hallmarks of AD—Aβ plaques. As a result, Aβ plaques have been extensively studied after being first described over a century ago. Advances in brain imaging and quantitative measures of Aβ in biological fluids have yielded insight into the time course of plaque development decades before and after AD symptom onset. However, despite the fundamental role of Aβ plaques in AD, in vivo measures of individual plaque growth, growth distribution, and dynamics are still lacking. To address this question, we combined stable isotope labeling kinetics (SILK and nanoscale secondary ion mass spectrometry (NanoSIMS imaging in an approach termed SILK–SIMS to resolve plaque dynamics in three human AD brains. In human AD brain, plaques exhibit incorporation of a stable isotope tracer. Tracer enrichment was highly variable between plaques and the spatial distribution asymmetric with both quiescent and active nanometer sub-regions of tracer incorporation. These data reveal that Aβ plaques are dynamic structures with deposition rates over days indicating a highly active process. Here, we report the first, direct quantitative measures of in vivo deposition into plaques in human AD brain. Our SILK–SIMS studies will provide invaluable information on plaque dynamics in the normal and diseased brain and offer many new avenues for investigation into pathological mechanisms of the disease, with implications for therapeutic development.

Evaluation of crop residues on potassium kinetics in an acid soil and potassium use efficiency in potato-garlic sequence using tracer 86Rb

International Nuclear Information System (INIS)

Sud, K.C.

2005-01-01

Greenhouse and laboratory studies were conducted on an acid soil in order to evaluate the role of two crop residues i.e. paddy and wheat along with farmyard manure on potassium kinetics and its availability in the potato-garlic sequence using tracer 86 Rb. Under rapid equilibrium, application of crop residues of paddy, wheat straw and FYM were able to enhance soil pH and organic carbon content. In addition, their application helped in enhancing soil K availability indices like water soluble, available and non-exchangeable -K. This was further augmented by the Q/I studies using 86 Rb where application of organic residues helped in lowering the potassium buffering capacity of the soil. Greenhouse study supplemented the results obtained from laboratory study where application of crop residues/FYM were able to improve the potato yield significantly and maintained higher concentration of K in potato leaf at early growth stages. A significant correlation was obtained between leaf K and haulms-K with that of 86 Rb activities in potato leaf at 35 days and 86 Rb absorbed in the haulms, respectively. Residues/ FYM and PK application to potato left sufficient residual effect on succeeding garlic crop. In potato-garlic sequence, K recovery was highest with FYM while N and P recoveries were higher with wheat residues. The nutrient recoveries with PK application followed law of diminishing returns. (author)

Leucine kinetics from [2H3]- and [13C]leucine infused simultaneously by gut and vein

International Nuclear Information System (INIS)

Hoerr, R.A.; Matthews, D.E.; Bier, D.M.; Young, V.R.

1991-01-01

In amino acid tracer kinetic studies of the fed state, ingested amino acid may be taken up during its initial transit through splanchnic tissues and thus not enter the plasma compartment where tracer is infused. To investigate this possibility, adult human subjects received simultaneous intravenous (iv) and intragastric (ig) leucine tracer infusions, first during a postabsorptive (PA) 4-h primed continuous ig infusion of L-[1-13C]-leucine and L-[5,5,5-2H3]leucine iv, followed on a separate day by a fed infusion, in which an ig infusion of a liquid formula was started 2 h before the tracer infusion and continued throughout the tracer study. Subjects were accustomed to a constant experimental diet supplying 1.5 g protein.kg-1.day-1 and 41-45 kcal.kg-1.day-1 for 7 and 12 days before the PA and fed studies, respectively. For the PA study, plasma enrichment for the ig tracer was 3.34 +/- 0.27 (SE) mol + excess and for the iv tracer it was 4.18 +/- 0.10 (P less than 0.02). Enrichments of alpha-keto-isocaproic acid (KIC) were 3.24 +/- 0.16 (ig) and 3.02 +/- 0.14 (iv), respectively [not significant (NS)]. For the fed study, plasma leucine enrichment for the ig tracer was 2.15 +/- 0.14 and for the iv tracer was 2.84 +/- 0.09 (P less than 0.02). KIC enrichments were 2.02 +/- 0.08 (ig) and 2.24 +/- 0.08 (iv), respectively (NS). In the PA study, the ratio of the plasma leucine enrichments for the ig and iv tracers was 0.80 +/- 0.06 and in the fed experiment, 0.76 +/- 0.05, respectively

Tracers vs. trajectories in a coastal region

Science.gov (United States)

Engqvist, A.; Döös, K.

2008-12-01

Two different methods of estimating the water exchange through a Baltic coastal region have been used, consisting of particle trajectories and passive tracers. Water is traced from and to a small discharge region near the coast. The discharge material in this region is treated as zero dimensional particles or tracers with neutral buoyancy. The real discharge material could be a leakage of radio-nuclides through the sea floor from an underground repository of nuclear waste. Water exchange rates between the discharge region and the model domain are estimated using both forward and backward trajectories as well as passive tracers. The Lagrangian trajectories can account for the time evolution of the water exchange while the tracers give one average age per model grid box. Water exchange times such as residence time, age and transient times have been calculated with trajectories but only the average age (AvA) for tracers. The trajectory calculations provide a more detailed time evolution than the tracers. On the other hand the tracers are integrated "on-line" simultaneously in the sea circulation model with the same time step while the Lagrangian trajectories are integrated "off-line" from the stored model velocities with its inherent temporal resolution, presently one hour. The sub-grid turbulence is parameterised as a Laplacian diffusion for the passive tracers and with an extra stochastic velocity for trajectories. The importance of the parameterised sub-grid turbulence for the trajectories is estimated to give an extra diffusion of the same order as the Laplacian diffusion by comparing the Lagrangian dispersions with and without parameterisation. The results of the different methods are similar but depend on the chosen diffusivity coefficient with a slightly higher correlation between trajectories and tracers when integrated with a lower diffusivity coefficient.

Using Tracer Technology to Characterize Contaminated Pipelines

Energy Technology Data Exchange (ETDEWEB)

Maresca, Joseph, W., Jr., Ph.D.; Bratton, Wesley, L., Ph.D., P.E.; Dickerson, Wilhelmina; Hales, Rochelle

2005-12-30

The Pipeline Characterization Using Tracers (PCUT) technique uses conservative and partitioning, reactive or other interactive tracers to remotely determine the amount of contaminant within a run of piping or ductwork. The PCUT system was motivated by a method that has been successfully used to characterize subsurface soil contaminants and is similar in operation to that of a gas chromatography column. By injecting a ?slug? of both conservative and partitioning tracers at one end (or section) of the piping and measuring the time history of the concentration of the tracers at the other end (or another section) of the pipe, the presence, location, and amount of contaminant within the pipe or duct can be determined. The tracers are transported along the pipe or duct by a gas flow field, typically air or nitrogen, which has a velocity that is slow enough so that the partitioning tracer has time to interact with the contaminant before the tracer slug completely passes over the contaminate region. PCUT not only identifies the presence of contamination, it also can locate the contamination along the pipeline and quantify the amount of residual. PCUT can be used in support of deactivation and decommissioning (D&D) of piping and ducts that may have been contaminated with hazardous chemicals such as chlorinated solvents, petroleum products, radioactive materials, or heavy metals, such as mercury.

Recent and ancient recharge deciphered by multi-dating tracer technique

Science.gov (United States)

Dogramaci, Shawan; Cook, Peter; Mccallum, Jimes; Purtchert, Roland

2017-04-01

Determining groundwater residence time from environmental tracer concentrations obtained from open bores or long screened intervals is fraught with difficulty because the sampled water represents variety of ages. Information on the distribution of groundwater age is commonly obtained by measuring more than one tracer. We examined the use of the multi-tracer technique representing different time frames (39Ar, 85Kr, 14C, 3H, CFC 11- CFC-12 CFC-113, SF6 and Cl,) to decipher the groundwater ages sampled from long screened bores in a regional aquifer in the Pilbara region of northwest Australia. We then applied a technique that assumes limited details of the form of the age distribution. Tracer concentrations suggest that groundwater samples are a mixture of young and old water - the former is inferred to represent localised recharge from an adjacent creek, and the latter to be diffuse recharge. Using our method, we were able to identify distinct age components in the groundwater. The results suggest the presence of four distinct age groups; zero and 20 years, 50 to 100 years, 100 to 600 years and approximately 1000 years old. These relatively high recharge events were consistent with local recharge sources (50-100 years) and confirmed by palaeo-climate record obtained from lake sediments. We found that although the ages of these components were well constrained, the relative proportions of each component was highly sensitive to errors of environmental tracer data. Our results show that the method we implemented can identify distinct age groups in groundwater samples without prior knowledge of the age distribution. The presence of distinct recharge times gives insight into groundwater flow conditions over long periods of time.

Description and results of tracer tests conducted for a deep fracture zone within granitic rock at the Leuggern borehole

International Nuclear Information System (INIS)

Spane, F.A. jr.

1990-09-01

A tracer test program was planned at the Leuggern borehole, to provide hydrogeologic information concerning the fracture zone(s) intersected within the depth interval 1,634.9 - 1,688.9 m. The original design of the tracer-dilution test was to: establish a uniform tracer concentration within the test system, and then monitor (at ground surface) the decline of tracer concentration within the circulated test system fluid. Analysis of the tracer concentration decline pattern was expected to provide an estimate of the natural lateral flux and lateral hydraulic gradient for the isolated test interval. A later pump-back test was also designed to recover tracer that had been 'flushed' into the test section, during the previous closed-circulation period. Analysis of the tracer recovery pattern was expected to provide an estimate of the dispersivity within the intersected fracture system. Results obtained from 'arrival-time' information during the Eosin and Naphtionat injection/recovery phases indicate a downward vertical flow of approximately 195-225 ml/min in the isolated interval, from an analysis of the dilution levels of Uranin and Eosin during the injection/recovery periods, and review of field data, the top of the upper inflow zone was determined to be approximately 13 m below the top flow line and the bottom of the outflow zone to be approximately 3 to 5 meters above the bottom flow line. (author) 30 figs., tabs., 42 refs

Leucine kinetics from (2H3)- and ( sup 13 C)leucine infused simultaneously by gut and vein

Energy Technology Data Exchange (ETDEWEB)

Hoerr, R.A.; Matthews, D.E.; Bier, D.M.; Young, V.R. (Massachusetts Institute of Technology, Cambridge (USA))

1991-01-01

In amino acid tracer kinetic studies of the fed state, ingested amino acid may be taken up during its initial transit through splanchnic tissues and thus not enter the plasma compartment where tracer is infused. To investigate this possibility, adult human subjects received simultaneous intravenous (iv) and intragastric (ig) leucine tracer infusions, first during a postabsorptive (PA) 4-h primed continuous ig infusion of L-(1-13C)-leucine and L-(5,5,5-2H3)leucine iv, followed on a separate day by a fed infusion, in which an ig infusion of a liquid formula was started 2 h before the tracer infusion and continued throughout the tracer study. Subjects were accustomed to a constant experimental diet supplying 1.5 g protein.kg-1.day-1 and 41-45 kcal.kg-1.day-1 for 7 and 12 days before the PA and fed studies, respectively. For the PA study, plasma enrichment for the ig tracer was 3.34 +/- 0.27 (SE) mol + excess and for the iv tracer it was 4.18 +/- 0.10 (P less than 0.02). Enrichments of alpha-keto-isocaproic acid (KIC) were 3.24 +/- 0.16 (ig) and 3.02 +/- 0.14 (iv), respectively (not significant (NS)). For the fed study, plasma leucine enrichment for the ig tracer was 2.15 +/- 0.14 and for the iv tracer was 2.84 +/- 0.09 (P less than 0.02). KIC enrichments were 2.02 +/- 0.08 (ig) and 2.24 +/- 0.08 (iv), respectively (NS). In the PA study, the ratio of the plasma leucine enrichments for the ig and iv tracers was 0.80 +/- 0.06 and in the fed experiment, 0.76 +/- 0.05, respectively.

Standardized 15N tracer methods for the evaluation of the plasma protein turnover in clinical practice. 1

International Nuclear Information System (INIS)

Bornhak, H.

1984-01-01

Methods for quantitative isolation of plasma proteins or groups of proteins (total plasma or serum proteins, fibrin, total globulines, α, β, γ-globolines, albumin) are described based on combination of chromatography with precipitation and extraction techniques. These methods are adapted to the special requirements of 15 N analysis. They can be performed in clinic-chemical standard laboratories without special apparatuses or devices. The described procedures are the biochemico-analytical basis for the quantitative evaluation of tracer kinetics data by means of mathematic modelling. (author)

Toxicity of fluorescent tracers and their degradation byproducts

Directory of Open Access Journals (Sweden)

Philippe Gombert

2017-01-01

Full Text Available Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and air action. The paper presents firstly the laboratory degradation of a first batch of fluorescent tracers in contact with chlorine, in order to simulate their passage through a water treatment system for human consumption. A second batch of the same tracers is subjected to agents of natural degradation: ultraviolet illumination, sunlight and air sparging. Most tracers is degraded, and toxicity and ecotoxicity tests (on rats, daphniae and algae are performed on degradation byproducts. These tests do not show any acute toxicity but a low to moderate ecotoxicity. In conclusion, the most used fluorescent tracers of the Normandy karstic chalk and their artificial and natural degradation byproducts do not exhibit significant toxicity to humans and the aquatic environment, at the concentrations generally noted at the restitution points.

Small molecules as tracers in atmospheric secondary organic aerosol

Science.gov (United States)

Yu, Ge

Secondary organic aerosol (SOA), formed from in-air oxidation of volatile organic compounds, greatly affects human health and climate. Although substantial research has been devoted to SOA formation and evolution, the modeled and lab-generated SOA are still low in mass and degree of oxidation compared to ambient measurements. In order to compensate for these discrepancies, the aqueous processing pathway has been brought to attention. The atmospheric waters serve as aqueous reaction media for dissolved organics to undergo further oxidation, oligomerization, or other functionalization reactions, which decreases the vapor pressure while increasing the oxidation state of carbon atoms. Field evidence for aqueous processing requires the identification of tracer products such as organosulfates. We synthesized the standards for two organosulfates, glycolic acid sulfate and lactic acid sulfate, in order to measure their aerosol-state concentration from five distinct locations via filter samples. The water-extracted filter samples were analyzed by LC-MS. Lactic acid sulfate and glycolic acid sulfate were detected in urban locations in the United States, Mexico City, and Pakistan with varied concentrations, indicating their potential as tracers. We studied the aqueous processing reaction between glyoxal and nitrogen-containing species such as ammonium and amines exclusively by NMR spectrometry. The reaction products formic acid and several imidazoles along with the quantified kinetics were reported. The brown carbon generated from these reactions were quantified optically by UV-Vis spectroscopy. The organic-phase reaction between oxygen molecule and alkenes photosensitized by alpha-dicarbonyls were studied in the same manner. We observed the fast kinetics transferring alkenes to epoxides under simulated sunlight. Statistical estimations indicate a very effective conversion of aerosol-phase alkenes to epoxides, potentially forming organosulfates in a deliquescence event and

Determinants of [13N]ammonia kinetics in hepatic PET experiments: a minimal recirculatory model

International Nuclear Information System (INIS)

Weiss, Michael; Roelsgaard, Klaus; Bender, Dirk; Keiding, Susanne

2002-01-01

The aim of this study was the development of a modelling approach for the analysis of the systemic kinetics of the tracer nitrogen-13 ammonia administered for dynamic liver scanning. The radioactive half-life of this tracer is 9.8 min, which limits the time span in which data are available in a positron emission tomography experimental setting. A circulatory pharmacokinetic model was applied to the metabolism of ammonia in anaesthetised pigs, which incorporated data from serial measurements of [ 13 N]ammonia and [ 13 N]metabolite activity in arterial and portal venous blood together with blood flow rates through the portal vein and through the hepatic artery obtained over 20 min after intravenous injection of [ 13 N]ammonia. Model analysis showed that up to 20 min after injection the time course of [ 13 N]ammonia concentration in arterial blood is primarily determined by distribution kinetics (steady-state volume of distribution 1,856±531 ml kg -1 ). Simultaneous fitting of arterial ammonia and metabolite blood concentrations allowed for estimation of the hepatic [ 13 N]ammonia clearance (10.25±1.84 ml min -1 kg -1 ), which accounted for the formation of the circulating metabolites. (orig.)

The European Tracer Experiment - experimental results and database

International Nuclear Information System (INIS)

Nodop, K.; Connolly, R.; Girardi, F.

1997-01-01

As part of the European Tracer Experiment (ETEX) two successful atmospheric experiments were carried out in October and November, 1994. Perfluorocarbon (PFC) tracers were released into the atmosphere in Monterfil, Brittany, and air samples were taken at 168 stations in 17 European countries for 72 hours after the release. Upper air tracer measurements were made from three aircraft. During the first experiment a westerly air flow transported the tracer plume north-eastwards across Europe. During the second release the flow was eastwards. The results from the ground sampling network allowed the determination of the cloud evolution as far as Sweden, Poland and Bulgaria. Typical background concentrations of the tracer used are around 5 to 7 fl/l in ambient air. Concentrations in the plume ranged from 10 to above 200 fl/l. The tracer release characteristics, the tracer concentrations at the ground and in upper air, the routine and additional meteorological observations at the ground level and in upper air, trajectories derived from constant-level balloons and the meteorological input fields for long-range transport (LRT) models are assembled in the ETEX database. The ETEX database is accessible via the Internet

Exploring Hydrofluorocarbons as Groundwater Age Tracers (Invited)

Science.gov (United States)

Haase, K. B.; Busenberg, E.; Plummer, L. N.; Casile, G.; Sanford, W. E.

2013-12-01

Groundwater dating tracers are an essential tool for analyzing hydrologic conditions in groundwater systems. Commonly used tracers for dating post-1940's groundwater include sulfur hexafluoride (SF6), chlorofluorocarbons (CFCs), 3H-3He, and other isotopic tracers (85Kr, δ2H and δ18O isotopes, etc.). Each tracer carries a corresponding set of advantages and limitations imposed by field, analytical, and interpretive methods. Increasing the number available tracers is appealing, particularly if they possess inert chemical properties and unique temporal emission histories from other tracers. Atmospherically derived halogenated trace gases continue to hold untapped potential for new tracers, as they are generally inert and their emission histories are well documented. SF5CF3, and CFC-13 were previously shown to have application as dating tracers, though their low mixing ratios and low solubility require large amounts of water to be degassed for their quantification. Two related groups of compounds, hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are hypothesized to be potential age tracers, having similar mixing ratios to the CFCs and relatively high solubility. However, these compounds yield gas chromatography electron capture detector (GC-ECD) responses that are 10-2 -10-5 less than CFC-12, making purge and trap or field stripping GC-ECD approaches impractical. Therefore, in order to use dissolved HCFCs and HFCs as age tracers, different approaches are needed. To solve this problem, we developed an analytical method that uses an atomic emission detector (GC-AED) in place of an ECD to detect fluorinated compounds. In contrast to the ECD, the AED is a universally sensitive, highly linear, elementally specific detector. The new GC-AED system is being used to measure chlorodifluoromethane (HCFC-22), 1,1,1,2-tetrafluoroethane (HFC-134a), and other fluorinated compounds in one liter water samples to study their potential as age dating tracers. HCFC-22 is a

Evaluation of Parameter Uncertainty Reduction in Groundwater Flow Modeling Using Multiple Environmental Tracers

Science.gov (United States)

Arnold, B. W.; Gardner, P.

2013-12-01

Calibration of groundwater flow models for the purpose of evaluating flow and aquifer heterogeneity typically uses observations of hydraulic head in wells and appropriate boundary conditions. Environmental tracers have a wide variety of decay rates and input signals in recharge, resulting in a potentially broad source of additional information to constrain flow rates and heterogeneity. A numerical study was conducted to evaluate the reduction in uncertainty during model calibration using observations of various environmental tracers and combinations of tracers. A synthetic data set was constructed by simulating steady groundwater flow and transient tracer transport in a high-resolution, 2-D aquifer with heterogeneous permeability and porosity using the PFLOTRAN software code. Data on pressure and tracer concentration were extracted at well locations and then used as observations for automated calibration of a flow and transport model using the pilot point method and the PEST code. Optimization runs were performed to estimate parameter values of permeability at 30 pilot points in the model domain for cases using 42 observations of: 1) pressure, 2) pressure and CFC11 concentrations, 3) pressure and Ar-39 concentrations, and 4) pressure, CFC11, Ar-39, tritium, and He-3 concentrations. Results show significantly lower uncertainty, as indicated by the 95% linear confidence intervals, in permeability values at the pilot points for cases including observations of environmental tracer concentrations. The average linear uncertainty range for permeability at the pilot points using pressure observations alone is 4.6 orders of magnitude, using pressure and CFC11 concentrations is 1.6 orders of magnitude, using pressure and Ar-39 concentrations is 0.9 order of magnitude, and using pressure, CFC11, Ar-39, tritium, and He-3 concentrations is 1.0 order of magnitude. Data on Ar-39 concentrations result in the greatest parameter uncertainty reduction because its half-life of 269

TU-AB-202-11: Tumor Segmentation by Fusion of Multi-Tracer PET Images Using Copula Based Statistical Methods

International Nuclear Information System (INIS)

Lapuyade-Lahorgue, J; Ruan, S; Li, H; Vera, P

2016-01-01

Purpose: Multi-tracer PET imaging is getting more attention in radiotherapy by providing additional tumor volume information such as glucose and oxygenation. However, automatic PET-based tumor segmentation is still a very challenging problem. We propose a statistical fusion approach to joint segment the sub-area of tumors from the two tracers FDG and FMISO PET images. Methods: Non-standardized Gamma distributions are convenient to model intensity distributions in PET. As a serious correlation exists in multi-tracer PET images, we proposed a new fusion method based on copula which is capable to represent dependency between different tracers. The Hidden Markov Field (HMF) model is used to represent spatial relationship between PET image voxels and statistical dynamics of intensities for each modality. Real PET images of five patients with FDG and FMISO are used to evaluate quantitatively and qualitatively our method. A comparison between individual and multi-tracer segmentations was conducted to show advantages of the proposed fusion method. Results: The segmentation results show that fusion with Gaussian copula can receive high Dice coefficient of 0.84 compared to that of 0.54 and 0.3 of monomodal segmentation results based on individual segmentation of FDG and FMISO PET images. In addition, high correlation coefficients (0.75 to 0.91) for the Gaussian copula for all five testing patients indicates the dependency between tumor regions in the multi-tracer PET images. Conclusion: This study shows that using multi-tracer PET imaging can efficiently improve the segmentation of tumor region where hypoxia and glucidic consumption are present at the same time. Introduction of copulas for modeling the dependency between two tracers can simultaneously take into account information from both tracers and deal with two pathological phenomena. Future work will be to consider other families of copula such as spherical and archimedian copulas, and to eliminate partial volume

Use of medical imaging as an epidemiologic tracer

International Nuclear Information System (INIS)

Dartigues, J.F.

1987-01-01

Medical imaging is a source of data for clinical and epidemiological research just like any other factual information obtained during medical treatment. Medical imaging data, like any other information, are not really useful unless they are obtained in rigorously controlled and determined conditions, defined a priori in the research protocol. In order to be use as an epidemiologic tracer (that is, as a meaning of finding a given pathology in a given population and during a given time period), the imaging data have to be valid, reliable, and representative, of easy access and obtained at a low cost [fr

Final report of the TRUE Block Scale project. 2. Tracer tests in the block scale

Energy Technology Data Exchange (ETDEWEB)

Andersson, Peter; Byegaard, Johan [Geosigma AB, Uppsala (Sweden); Winberg, Anders [Conterra AB, Partille (Sweden)

2002-05-01

retardation noted in the injection. The evaluated K{sub a} values were found to be of a magnitude equitable to the TRUE- 1 laboratory K{sub a} values. Effects of matrix diffusion, sorption kinetics model, non-linear sorption were also explored. The evaluation and interpretation of the block scale tracer breakthrough curves indicated response of a heterogeneous system, observed both from tests in single structures and in network of structures. Results from the deterministic Structure 20 were found to show a signature of a narrow and high-conductive single structure, whereas results from Structure 21 indicated that it is probably more complex than assumed at the onset of the investigation, probably made up of several sub-parallel structures, rather than a single fracture. The network flow paths generally have less steep tails (t{sup -4/2} - t{sup -3/2}) in log-log space than the single structure flow paths. The observed order of retention among the different species was found to be the same as in TRUE-1 and in the laboratory tests, i.e. Na{sup +}tracer was recovered compared to the conservative tracer (R{sub 50%}), was about the same for most species when comparing TRUE-1 data to the results of 17 m single structure flow paths (C1 and C4) in Structure 20. However, for the breakthroughs of sorbing tracers in the more complex flow paths C3 (Na{sup +}) and C2(Ca{sup 2+}) a 30-80% stronger retardation (expressed as R{sub 50%}) was noted. The reasons for this somewhat enhanced retardation between the two slower and more complicated flow paths (C2 and C3) and the single structure flow paths (C 1 and C4) may be several; e.g. presence of gouge material (fine-grained fault gouge) in the structures, presence of gouge material in fracture intersection zones, differences in the mineralogy along the flow

Final report of the TRUE Block Scale project. 2. Tracer tests in the block scale

International Nuclear Information System (INIS)

Andersson, Peter; Byegaard, Johan; Winberg, Anders

2002-05-01

. The evaluated K a values were found to be of a magnitude equitable to the TRUE- 1 laboratory K a values. Effects of matrix diffusion, sorption kinetics model, non-linear sorption were also explored. The evaluation and interpretation of the block scale tracer breakthrough curves indicated response of a heterogeneous system, observed both from tests in single structures and in network of structures. Results from the deterministic Structure 20 were found to show a signature of a narrow and high-conductive single structure, whereas results from Structure 21 indicated that it is probably more complex than assumed at the onset of the investigation, probably made up of several sub-parallel structures, rather than a single fracture. The network flow paths generally have less steep tails (t -4/2 - t -3/2 ) in log-log space than the single structure flow paths. The observed order of retention among the different species was found to be the same as in TRUE-1 and in the laboratory tests, i.e. Na + 2≅ Sr 2+ 2+ ≅Rb + + . Another similarity was tha the retardation, expressed as the ratio of the time at which 50% of the sorbing tracer was recovered compared to the conservative tracer (R 50% ), was about the same for most species when comparing TRUE-1 data to the results of 17 m single structure flow paths (C1 and C4) in Structure 20. However, for the breakthroughs of sorbing tracers in the more complex flow paths C3 (Na + ) and C2(Ca 2+ ) a 30-80% stronger retardation (expressed as R 50% ) was noted. The reasons for this somewhat enhanced retardation between the two slower and more complicated flow paths (C2 and C3) and the single structure flow paths (C 1 and C4) may be several; e.g. presence of gouge material (fine-grained fault gouge) in the structures, presence of gouge material in fracture intersection zones, differences in the mineralogy along the flow paths, larger portions of stagnant water to interact with along the flow path, higher porosity in the fracture rim zone

Case study: evaluation of the performance of water treatment units by the use of tracer techniques

International Nuclear Information System (INIS)

Sebastian, C.; Maghella, G.; Mamani, E.

2000-12-01

Very often, water treatment systems do not reach the expected performance due to disturbances of hydraulic order, which cause malfunctioning in the flow through such systems. Tracer techniques have proved to be very useful to obtain information on the system or a part of it, by means of observation of the released tracer or observation of the released tracer during its progress into the system or at the output of the same. This paper is a report of the behavior of a set of both sand settlement unit and hydraulic flocculators in a potable water plant, through the analysis of radiotracers response curves or residence time distribution curves. The tracers released into the system consists in an aqueous solution of Iodine-131 with very low activity, in order to get a dynamic behave similar to the one of the fluid under investigation

Heat tracer methods

Science.gov (United States)

Healy, Richard W.; Scanlon, Bridget R.

2010-01-01

The flow of heat in the subsurface is closely linked to the movement of water (Ingebritsen et al., 2006). As such, heat has been used as a tracer in groundwater studies for more than 100 years (Anderson, 2005). As with chemical and isotopic tracers (Chapter 7), spatial or temporal trends in surface and subsurface temperatures can be used to infer rates of water movement. Temperature can be measured accurately, economically, at high frequencies, and without the need to obtain water samples, facts that make heat an attractive tracer. Temperature measurements made over space and time can be used to infer rates of recharge from a stream or other surface water body (Lapham, 1989; Stonestrom and Constantz, 2003); measurements can also be used to estimate rates of steady drainage through depth intervals within thick unsaturated zones (Constantz et al., 2003; Shan and Bodvarsson, 2004). Several thorough reviews of heat as a tracer in hydrologic studies have recently been published (Constantz et al., 2003; Stonestrom and Constantz, 2003; Anderson, 2005; Blasch et al., 2007; Constantz et al., 2008). This chapter summarizes heat-tracer approaches that have been used to estimate recharge.Some clarification in terminology is presented here to avoid confusion in descriptions of the various approaches that follow. Diffuse recharge is that which occurs more or less uniformly across large areas in response to precipitation, infiltration, and drainage through the unsaturated zone. Estimates of diffuse recharge determined using measured temperatures in the unsaturated zone are referred to as potential recharge because it is possible that not all of the water moving through the unsaturated zone will recharge the aquifer; some may be lost to the atmosphere by evaporation or plant transpiration. Estimated fluxes across confining units in the saturated zone are referred to as interaquifer flow (Chapter 1). Focused recharge is that which occurs directly from a point or line source, such

Use of Helium-3 and Tritium tracers in oceanography

International Nuclear Information System (INIS)

Andrie, Chantal

1987-01-01

As tritium considered as a transient tracer has become one of the most promising tool for the study of oceanic circulation and of the ocean capacity to absorb anthropogenic carbon, and as the simultaneous use of its radioactive descendant, Helium-3, brings an additional information (together, these tracers build up a clock in the study of water masses), and as all helium-3 and tritium measurements are made by mass spectroscopy, this research thesis addresses the analytical process, the detection limit, and the method reproducibility associated with this use of both tracers. The author reports and discusses helium-3 data obtained during a measurement campaign which allowed the localisation of an active source and the evidence of an intermediate back current, and tritium data obtained during another measurement campaign which allowed the description of the high time variability of convection processes, and an assessment of water renewal delays and of some deep water circulations. He also reports and discusses the simultaneous use of helium-3 data and tritium data to localize areas where convection processes occur. A theoretical approach to this simultaneous use is proposed which uses a mixing model which distinguishes the venting transit time. Measurement campaigns were performed in Red Sea, western Mediterranean Sea, and north-eastern Atlantic Ocean [fr

18O isotopic tracer studies of silicon oxidation in dry oxygen

International Nuclear Information System (INIS)

Han, C.J.

1986-01-01

Oxidation of silicon in dry oxygen has been an important process in the integrated circuit industry for making gate insulators on metal-oxide-semiconductory (MOS) devices. This work examines this process using isotopic tracers of oxygen to determine the transport mechanisms of oxygen through silicon dioxide. Oxides were grown sequentially using mass-16 and mass-18 oxygen gas sources to label the oxygen molecules from each step. The resulting oxides are analyzed using secondary ion mass spectrometry (SIMS). The results of these analyses suggest two oxidant species are present during the oxidation, each diffuses and oxidizes separately during the process. A model from this finding using a sum of two linear-parabolic growth rates, each representing the growth rate from one of the oxidants, describes the reported oxidation kinetics in the literature closely. A fit of this relationship reveals excellent fits to the data for oxide thicknesses ranging from 30 A to 1 μm and for temperatures ranging from 800 to 1200 0 C. The mass-18 oxygen tracers also enable a direct observation of the oxygen solubility in the silicon dioxide during a dry oxidation process. The SIMS profiles establish a maximum solubility for interstitial oxygen at 1000 0 C at 2 x 10 20 cm -3 . Furthermore, the mass-18 oxygen profiles show negligible network diffusion during an 1000 0 C oxidation

In vivo and in vitro characterization of [18F]-FE-(+)-DTBZ as a tracer for beta-cell mass

International Nuclear Information System (INIS)

Eriksson, Olof; Jahan, Mahabuba; Johnstroem, Peter; Korsgren, Olle; Sundin, Anders; Halldin, Christer; Johansson, Lars

2010-01-01

Introduction: The positron emission tomography (PET) tracer 9-[ 18 F]fluoroethyl-(+)-dihydrotetrabenazine ([ 18 F]-FE-(+)-DTBZ) is a potential candidate for quantifying beta-cell mass in vivo. The purpose was to investigate in vitro and in vivo utility of this tracer for the assessment of beta-cell mass. Methods: Three pigs were intravenously administered [ 18 F]-FE-(+)-DTBZ and examined by PET/computed tomography. Binding parameters were estimated by kinetic modeling. In vitro k D and B max were determined by saturation binding studies of endocrine and exocrine human tissue homogenates. In vitro pancreatic uptake was determined by tissue autoradiography with pancreases from patients with types 1 (T1DM) and 2 diabetes mellitus (T2DM) and healthy controls. Results: [ 18 F]-FE-(+)-DTBZ had a k D of 3.5±1.0 nM, a B max of 382±108 fmol/mg protein and a specificity of 89±1.8% in islet homogenates. The total exocrine uptake was lower and 65% was nondisplaceable. No uptake difference was observed in pancreatic tissue slices from patients with T1DM, T2DM or healthy controls. The in vivo porcine pancreatic uptake reached a peak of standardized uptake value (SUV) of 2.8 with a low distribution volume ratio in all animals. Moderate to high tracer uptake was identified in the bile system and in bone. Conclusions: [ 18 F]-FE-(+)-DTBZ binds to vesicular monoamine transporter 2 (VMAT2) with high specificity in pure islet tissue in vitro. However, there is high nondisplaceable binding to exocrine tissue. In addition, in vivo tracer metabolism and dehalogenation result in severe underestimation of porcine pancreatic VMAT2 expression and BCM. The results do not support [ 18 F]-FE-(+)-DTBZ as a suitable tracer for in vivo beta-cell imaging.

PC-based hardware and software for tracer measurements

International Nuclear Information System (INIS)

Kaemaeraeinen, V.J.; Kall, Leif; Kaeki, Arvo

1990-01-01

Cheap, efficient personal computers can be used for both measurement and analysis. The results can be calculated immediately after the measurements are made in order to exploit the real-time measuring capabilities of tracer techniques fully. In the analysis phase the measurement information is visualized using graphical methods. The programs are menu drive to make them easy to use and adaptable for field conditions. The measuring equipment is modular for easy installation and maintenance. (author)

Rate equations for tracer studies in recirculating reactors

Energy Technology Data Exchange (ETDEWEB)

Happel, J [Columbia Univ., New York (USA). Dept. of Chemical Engineering

1974-10-01

The employment of isotopic tracers is a useful technique for gaining insight into the rate controlling steps of a complex chemical reaction such as is frequently encountered in heterogeneous catalysis. An effective procedure has been to superpose tracer transfer on a reaction which is occurring under steady state conditions. If tracer transfer is employed in this fashion it is often possible to assess the individual step velocities in an assumed reaction mechanism. If transient transfer of tracer is now introduced it is possible in addition to estimate surface concentrations of chemisorbed species. The purpose of the present paper is to present the mathematical relationships involved when transfer of the tracer is not differential in the investigation. For this purpose a simple example is chosen to illustrate the various possibilities involved.

Rate equations for tracer studies in recirculatinng reactors

International Nuclear Information System (INIS)

Happel, J.

1974-01-01

The employment of isotopic tracers is a useful technique for gaining insight into the rate controlling steps of a complex chemical reaction such as is frequently encountered in heterogeneous catalysis. An effective procedure has been to superpose tracer transfer on a reaction which is occurring under steady state conditions. If tracer transfer is employed in this fashion it is often possible to assess the individual step velocities in an assumed reaction mechanism. If transient transfer of tracer is now introduced it is possible in addition to estimate surface concentrations of chemisorbed species. The purpose of the present paper is to present the mathematical relationships involved when transfer of the tracer is not differential in the investigation. For this purpose a simple example is chosen to illustrate the various possibilities involved. (auth.)

Tracer Testing for Estimating Heat Transfer Area in Fractured Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Pruess, Karsten; van Heel, Ton; Shan, Chao

2004-05-12

A key parameter governing the performance and life-time of a Hot Fractured Rock (HFR) reservoir is the effective heat transfer area between the fracture network and the matrix rock. We report on numerical modeling studies into the feasibility of using tracer tests for estimating heat transfer area. More specifically, we discuss simulation results of a new HFR characterization method which uses surface-sorbing tracers for which the adsorbed tracer mass is proportional to the fracture surface area per unit volume. Sorption in the rock matrix is treated with the conventional formulation in which tracer adsorption is volume-based. A slug of solute tracer migrating along a fracture is subject to diffusion across the fracture walls into the adjacent rock matrix. Such diffusion removes some of the tracer from the fluid in the fractures, reducing and retarding the peak in the breakthrough curve (BTC) of the tracer. After the slug has passed the concentration gradient reverses, causing back-diffusion from the rock matrix into the fracture, and giving rise to a long tail in the BTC of the solute. These effects become stronger for larger fracture-matrix interface area, potentially providing a means for estimating this area. Previous field tests and modeling studies have demonstrated characteristic tailing in BTCs for volatile tracers in vapor-dominated reservoirs. Simulated BTCs for solute tracers in single-phase liquid systems show much weaker tails, as would be expected because diffusivities are much smaller in the aqueous than in the gas phase, by a factor of order 1000. A much stronger signal of fracture-matrix interaction can be obtained when sorbing tracers are used. We have performed simulation studies of surface-sorbing tracers by implementing a model in which the adsorbed tracer mass is assumed proportional to the fracture-matrix surface area per unit volume. The results show that sorbing tracers generate stronger tails in BTCs, corresponding to an effective

Analysis of tracer responses in the BULLION Forced-Gradient Experiment at Pahute Mesa, Nevada

Energy Technology Data Exchange (ETDEWEB)

Paul W. Reimus; Marc J. Haga

1999-10-01

This report presents an analysis of the tracer data from the BULLION forced-gradient experiment (FGE) conducted on Pahute Mesa at the Nevada Test Site from June 2, 1997 through August 28, 1997, for the Underground Test Area (UGTA) Program. It also serves to document the polystyrene microsphere data from the FGE. The FGE involved the injection of solute and colloid tracers into wells ER-20-6 No. 1 and ER-20-6 No. 2 while ER-20-6 No. 3 was pumped at approximately 116 gallons per minute (gpm). The experimental configuration and test design are described briefly in this report; more details are provided elsewhere (IT, 1996, 1997, 1998). The tracer responses in the various wells yielded valuable information about transport processes such as longitudinal dispersion, matrix diffusion and colloid transport in the hydrogeologic system in the vicinity of the BULLION nuclear test cavity. Parameter values describing these processes are derived from the semi-analytical model interpretations presented in this report. A companion report (IT, 1998) presents more detailed numerical modeling interpretations of the solute tracer responses.

Analysis of tracer responses in the BULLION Forced-Gradient Experiment at Pahute Mesa, Nevada

International Nuclear Information System (INIS)

Reimus, Paul W.; Haga, Marc J.

1999-01-01

This report presents an analysis of the tracer data from the BULLION forced-gradient experiment (FGE) conducted on Pahute Mesa at the Nevada Test Site from June 2, 1997 through August 28, 1997, for the Underground Test Area (UGTA) Program. It also serves to document the polystyrene microsphere data from the FGE. The FGE involved the injection of solute and colloid tracers into wells ER-20-6 No. 1 and ER-20-6 No. 2 while ER-20-6 No. 3 was pumped at approximately 116 gallons per minute (gpm). The experimental configuration and test design are described briefly in this report; more details are provided elsewhere (IT, 1996, 1997, 1998). The tracer responses in the various wells yielded valuable information about transport processes such as longitudinal dispersion, matrix diffusion and colloid transport in the hydrogeologic system in the vicinity of the BULLION nuclear test cavity. Parameter values describing these processes are derived from the semi-analytical model interpretations presented in this report. A companion report (IT, 1998) presents more detailed numerical modeling interpretations of the solute tracer responses

Kinetic parametric estimation in animal PET molecular imaging based on artificial immune network

International Nuclear Information System (INIS)

Chen Yuting; Ding Hong; Lu Rui; Huang Hongbo; Liu Li

2011-01-01

Objective: To develop an accurate,reliable method without the need of initialization in animal PET modeling for estimation of the tracer kinetic parameters based on the artificial immune network. Methods: The hepatic and left ventricular time activity curves (TACs) were obtained by drawing ROIs of liver tissue and left ventricle on dynamic 18 F-FDG PET imaging of small mice. Meanwhile, the blood TAC was analyzed by sampling the tail vein blood at different time points after injection. The artificial immune network for parametric optimization of pharmacokinetics (PKAIN) was adapted to estimate the model parameters and the metabolic rate of glucose (K i ) was calculated. Results: TACs of liver,left ventricle and tail vein blood were obtained.Based on the artificial immune network, K i in 3 mice was estimated as 0.0024, 0.0417 and 0.0047, respectively. The average weighted residual sum of squares of the output model generated by PKAIN was less than 0.0745 with a maximum standard deviation of 0.0084, which indicated that the proposed PKAIN method can provide accurate and reliable parametric estimation. Conclusion: The PKAIN method could provide accurate and reliable tracer kinetic modeling in animal PET imaging without the need of initialization of model parameters. (authors)

Lanthanide-based fluorescent tracers in complex media

International Nuclear Information System (INIS)

Brichart, Thomas

2014-01-01

Tracers are objects allowing the determination of the position or the distribution of a product; tracers are currently used in a great variety of domains. Despite the fact that each field has it's own specifications, it is possible to find tracers in medicine (contrast agents), anti-counterfeiting or geological exploration. We have developed lanthanide complex tracers for oil field injection waters. Those tracers, derived from the DOTA, have been detected at concentration lower than 1 ppb, thanks to a simple and compact apparatus. This detection has been made possible by the use of time-resolved fluorescence spectroscopy, this technique allows us to get rid of the background noise created by the intrinsic fluorescence of oil residues that are present in production waters. We also demonstrated how we can, through a reverse microemulsion synthesis, encapsulate several different dyes inside a single nanoparticle composed of a gold core and a silica shell. We showed as well, how those particles can be used as smart tracers to gather data, such as temperature, pH, solvents, etc. inside the well. Finally the use of lanthanides and scale inhibitors properties allowed us to create a simple and fast dosing protocol of such scale inhibitors in injection waters. This dosage will then allow the quick adjustment of their concentration inside each well. (author) [fr

Fluorescence characteristics of the fuel tracers triethylamine and trimethylamine for the investigation of fuel distribution in internal combustion engines.

Science.gov (United States)

Lind, Susanne; Aßmann, Simon; Zigan, Lars; Will, Stefan

2016-03-01

Laser-induced fluorescence based on fuel tracers like amines is a suitable measurement technique for mixing studies in internal combustion (IC) engines. Triethylamine has often been used in gasoline IC engines; however, no detailed fluorescence characterization for excitation at 263 or 266 nm is available. Trimethylamine (TMA) exhibits high potential as a gaseous fuel tracer but little information about TMA fluorescence is currently available. A picosecond laser source combined with a streak camera equipped with a spectrograph was used to determine the spectral fluorescence emission and fluorescence decay time of both tracers. The tracers were investigated at various temperatures and pressures in a calibration cell with nitrogen as bath gas. The results provide an in-depth understanding of the fluorescence characteristics of both tracers and allow assessment of their application to the investigation of fuel distribution in IC engines.

Multimodel analysis of anisotropic diffusive tracer-gas transport in a deep arid unsaturated zone

Science.gov (United States)

Green, Christopher T.; Walvoord, Michelle Ann; Andraski, Brian J.; Striegl, Robert G.; Stonestrom, David A.

2015-01-01

Gas transport in the unsaturated zone affects contaminant flux and remediation, interpretation of groundwater travel times from atmospheric tracers, and mass budgets of environmentally important gases. Although unsaturated zone transport of gases is commonly treated as dominated by diffusion, the characteristics of transport in deep layered sediments remain uncertain. In this study, we use a multimodel approach to analyze results of a gas-tracer (SF6) test to clarify characteristics of gas transport in deep unsaturated alluvium. Thirty-five separate models with distinct diffusivity structures were calibrated to the tracer-test data and were compared on the basis of Akaike Information Criteria estimates of posterior model probability. Models included analytical and numerical solutions. Analytical models provided estimates of bulk-scale apparent diffusivities at the scale of tens of meters. Numerical models provided information on local-scale diffusivities and feasible lithological features producing the observed tracer breakthrough curves. The combined approaches indicate significant anisotropy of bulk-scale diffusivity, likely associated with high-diffusivity layers. Both approaches indicated that diffusivities in some intervals were greater than expected from standard models relating porosity to diffusivity. High apparent diffusivities and anisotropic diffusivity structures were consistent with previous observations at the study site of rapid lateral transport and limited vertical spreading of gas-phase contaminants. Additional processes such as advective oscillations may be involved. These results indicate that gases in deep, layered unsaturated zone sediments can spread laterally more quickly, and produce higher peak concentrations, than predicted by homogeneous, isotropic diffusion models.

[18F]Fluoroethylflumazenil: a novel tracer for PET imaging of human benzodiazepine receptors

International Nuclear Information System (INIS)

Gruender, G.; Lange-Asschenfeldt, C.; Vernaleken, I.; Lueddens, H.; Siessmeier, T.; Buchholz, H.-G.; Bartenstein, P.; Stoeter, P.; Drzezga, A.; Roesch, F.

2001-01-01

5-(2'-[ 18 F]Fluoroethyl)flumazenil ([ 18 F]FEF) is a fluorine-18 labelled positron emission tomography (PET) tracer for central benzodiazepine receptors. Compared with the established [ 11 C]flumazenil, it has the advantage of the longer half-life of the fluorine-18 label. After optimisation of its synthesis and determination of its in vitro receptor affinities, we performed first PET studies in humans. PET studies in seven healthy human volunteers were performed on a Siemens ECAT EXACT whole-body scanner after injection of 100-280 MBq [ 18 F]FEF. In two subjects, a second PET scan was conducted after pretreatment with unlabelled flumazenil (1 mg or 2.5 mg i.v., 3 min before tracer injection). A third subject was studied both with [ 18 F]FEF and with [ 11 C]flumazenil. Brain radioactivity was measured for 60-90 min p.i. and analysed with a region of interest-oriented approach and on a voxelwise basis with spectral analysis. Plasma radioactivity was determined from arterial blood samples and metabolites were determined by high-performance liquid chromatography. In human brain, maximum radioactivity accumulation was observed 4±2 min p.i., with a fast clearance kinetics resulting in 50% and 20% of maximal activities at about 10 and 30 min, respectively. [ 18 F]FEF uptake followed the known central benzodiazepine receptor distribution in the human brain (occipital cortex >temporal cortex >cerebellum >thalamus >pons). Pretreatment with unlabelled flumazenil resulted in reduced tracer uptake in all brain areas except for receptor-free reference regions like the pons. Parametric images of distribution volume and binding potential generated on a voxelwise basis revealed two- to three-fold lower in vivo receptor binding of [ 18 F]FEF compared with [ 11 C]flumazenil, while relative uptake of [ 18 F]FEF was higher in the cerebellum, most likely owing to its relatively higher affinity for benzodiazepine receptors containing the α6 subunit. Metabolism of [ 18 F]FEF was very

Quantitative amino acid profiling and stable isotopically labeled amino acid tracer enrichment used for in vivo human systemic and tissue kinetics measurements

DEFF Research Database (Denmark)

Bornø, Andreas; van Hall, Gerrit

2014-01-01

An important area within clinical functional metabolomics is in vivo amino acid metabolism and protein turnover measurements for which accurate amino acid concentrations and stable isotopically labeled amino acid enrichments are mandatory not the least when tissue metabolomics is determined....... The present study describes a new sensitive liquid chromatography tandem mass-spectrometry method quantifying 20 amino acids and their tracer(s) ([ring-(13)C6]/D5Phenylalanine) in human plasma and skeletal muscle specimens. Before analysis amino acids were extracted and purified via deprotonization....../ion exchange, derivatized using a phenylisothiocyanate reagent and each amino acid was quantitated with its own stable isotopically labeled internal standard (uniformly labeled-(13)C/(15)N). The method was validated according to general recommendations for chromatographic analytical methods. The calibration...

Assessment of input function distortions on kinetic model parameters in simulated dynamic 82Rb PET perfusion studies

International Nuclear Information System (INIS)

Meyer, Carsten; Peligrad, Dragos-Nicolae; Weibrecht, Martin

2007-01-01

Cardiac 82 rubidium dynamic PET studies allow quantifying absolute myocardial perfusion by using tracer kinetic modeling. Here, the accurate measurement of the input function, i.e. the tracer concentration in blood plasma, is a major challenge. This measurement is deteriorated by inappropriate temporal sampling, spillover, etc. Such effects may influence the measured input peak value and the measured blood pool clearance. The aim of our study is to evaluate the effect of input function distortions on the myocardial perfusion as estimated by the model. To this end, we simulate noise-free myocardium time activity curves (TACs) with a two-compartment kinetic model. The input function to the model is a generic analytical function. Distortions of this function have been introduced by varying its parameters. Using the distorted input function, the compartment model has been fitted to the simulated myocardium TAC. This analysis has been performed for various sets of model parameters covering a physiologically relevant range. The evaluation shows that ±10% error in the input peak value can easily lead to ±10-25% error in the model parameter K 1 , which relates to myocardial perfusion. Variations in the input function tail are generally less relevant. We conclude that an accurate estimation especially of the plasma input peak is crucial for a reliable kinetic analysis and blood flow estimation

Masked-Volume-Wise PCA and "reference Logan" illustrate similar regional differences in kinetic behavior in human brain PET study using [11C]-PIB

Directory of Open Access Journals (Sweden)

Engler Henry

2009-01-01

Full Text Available Abstract Background Kinetic modeling using reference Logan is commonly used to analyze data obtained from dynamic Positron Emission Tomography (PET studies on patients with Alzheimer's disease (AD and healthy volunteers (HVs using amyloid imaging agent N-methyl [11C]2-(4'-methylaminophenyl-6-hydroxy-benzothiazole, [11C]-PIB. The aim of the present study was to explore whether results obtained using the newly introduced method, Masked Volume Wise Principal Component Analysis, MVW-PCA, were similar to the results obtained using reference Logan. Methods MVW-PCA and reference Logan were performed on dynamic PET images obtained from four Alzheimer's disease (AD patients on two occasions (baseline and follow-up and on four healthy volunteers (HVs. Regions of interest (ROIs of similar sizes were positioned in different parts of the brain in both AD patients and HVs where the difference between AD patients and HVs is largest. Signal-to-noise ratio (SNR and discrimination power (DP were calculated for images generated by the different methods and the results were compared both qualitatively and quantitatively. Results MVW-PCA generated images that illustrated similar regional binding patterns compared to reference Logan images and with slightly higher quality, enhanced contrast, improved SNR and DP, without being based on modeling assumptions. MVW-PCA also generated additional MVW-PC images by using the whole dataset, which illustrated regions with different and uncorrelated kinetic behaviors of the administered tracer. This additional information might improve the understanding of kinetic behavior of the administered tracer. Conclusion MVW-PCA is a potential multivariate method that without modeling assumptions generates high quality images, which illustrated similar regional changes compared to modeling methods such as reference Logan. In addition, MVW-PCA could be used as a new technique, applicable not only on dynamic human brain studies but also on

Industrial tracer application in people's republic of china

International Nuclear Information System (INIS)

Sun Maoyi

1987-01-01

A number of important applications of radioisotopes and their compounds used as tracers in petroleum industry, metallurgical industry, mechanical industry, chemical industry, electronic industry, hydrology and water conservancy in China are introduced in this paper. And the tracer technique applied to entomology is also mentioned. The industrial tracer applications are successful and beneficial in People's Republic of China from the examples given. (author)

Journal: A Review of Some Tracer-Test Design Equations for ...

Science.gov (United States)

Determination of necessary tracer mass, initial sample-collection time, and subsequent sample-collection frequency are the three most difficult aspects to estimate for a proposed tracer test prior to conducting the tracer test. To facilitate tracer-mass estimation, 33 mass-estimation equations are reviewed here, 32 of which were evaluated using previously published tracer-test design examination parameters. Comparison of the results produced a wide range of estimated tracer mass, but no means is available by which one equation may be reasonably selected over the others. Each equation produces a simple approximation for tracer mass. Most of the equations are based primarily on estimates or measurements of discharge, transport distance, and suspected transport times. Although the basic field parameters commonly employed are appropriate for estimating tracer mass, the 33 equations are problematic in that they were all probably based on the original developers' experience in a particular field area and not necessarily on measured hydraulic parameters or solute-transport theory. Suggested sampling frequencies are typically based primarily on probable transport distance, but with little regard to expected travel times. This too is problematic in that tends to result in false negatives or data aliasing. Simulations from the recently developed efficient hydrologic tracer-test design methodology (EHTD) were compared with those obtained from 32 of the 33 published tracer-

Tracer tests Wairakei

International Nuclear Information System (INIS)

McCabe, W.J.; Manning, M.R.; Barry, B.J.

1980-07-01

The report summarises the radioactive tracer tests, using iodine-131 and bromine-82, made in the Wairakei geothermal field over the period 1978-80. Injection of tracer into three wells with strong cool water downflows at about 300-400m below ground level, produced strong rapid responses from the only deep wells feeding from about 800-1000m and lying in the south-westerly direction from the injection wells, i.e. parallel to the fault planes. Shallower wells, even though in some cases much closer to the injection well, reacted much more slowly. Velocities, as measured by peak arrival times, as high as 22m/h over 200m and 11m/h over 650m, were found. The flow patterns for the cool water feeds to the production area are discussed

Natural radium and radon tracers to quantify water exchange and movement in reservoirs

Science.gov (United States)

Smith, Christopher G.; Baskaran, Mark

2011-01-01

Radon and radium isotopes are routinely used to quantify exchange rates between different hydrologic reservoirs. Since their recognition as oceanic tracers in the 1960s, both radon and radium have been used to examine processes such as air-sea exchange, deep oceanic mixing, benthic inputs, and many others. Recently, the application of radon-222 and the radium-quartet (223,224,226,228Ra) as coastal tracers has seen a revelation with the growing interest in coastal groundwater dynamics. The enrichment of these isotopes in benthic fluids including groundwater makes both radium and radon ideal tracers of coastal benthic processes (e.g. submarine groundwater discharge). In this chapter we review traditional and recent advances in the application of radon and radium isotopes to understand mixing and exchange between various hydrologic reservoirs, specifically: (1) atmosphere and ocean, (2) deep and shallow oceanic water masses, (3) coastal groundwater/benthic pore waters and surface ocean, and (4) aquifer-lakes. While the isotopes themselves and their distribution in the environment provide qualitative information about the exchange processes, it is mixing/exchange and transport models for these isotopes that provide specific quantitative information about these processes. Brief introductions of these models and mixing parameters are provided for both historical and more recent studies.

TRACER - TRACING AND CONTROL OF ENGINEERING REQUIREMENTS

Science.gov (United States)

Turner, P. R.

1994-01-01

TRACER (Tracing and Control of Engineering Requirements) is a database/word processing system created to document and maintain the order of both requirements and descriptive material associated with an engineering project. A set of hierarchical documents are normally generated for a project whereby the requirements of the higher level documents levy requirements on the same level or lower level documents. Traditionally, the requirements are handled almost entirely by manual paper methods. The problem with a typical paper system, however, is that requirements written and changed continuously in different areas lead to misunderstandings and noncompliance. The purpose of TRACER is to automate the capture, tracing, reviewing, and managing of requirements for an engineering project. The engineering project still requires communications, negotiations, interactions, and iterations among people and organizations, but TRACER promotes succinct and precise identification and treatment of real requirements separate from the descriptive prose in a document. TRACER permits the documentation of an engineering project's requirements and progress in a logical, controllable, traceable manner. TRACER's attributes include the presentation of current requirements and status from any linked computer terminal and the ability to differentiate headers and descriptive material from the requirements. Related requirements can be linked and traced. The program also enables portions of documents to be printed, individual approval and release of requirements, and the tracing of requirements down into the equipment specification. Requirement "links" can be made "pending" and invisible to others until the pending link is made "binding". Individuals affected by linked requirements can be notified of significant changes with acknowledgement of the changes required. An unlimited number of documents can be created for a project and an ASCII import feature permits existing documents to be incorporated

Kinetic inductance detectors for far-infrared spectroscopy

International Nuclear Information System (INIS)

Barlis, A.; Aguirre, J.; Stevenson, T.

2016-01-01

The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

Kinetic inductance detectors for far-infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Barlis, A., E-mail: abarlis@physics.upenn.edu [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Aguirre, J. [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Stevenson, T. [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)

2016-07-11

The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

Hypoxia positron emission tomography imaging: combining information on perfusion and tracer retention to improve hypoxia specificity

DEFF Research Database (Denmark)

Busk, Morten; Munk, Ole L; Jakobsen, Steen S

2017-01-01

BACKGROUND: Static positron emission tomography (PET) allows mapping of tumor hypoxia, but low resolution and slow tracer retention/clearance results in poor image contrast and the risk of missing areas where hypoxic cells and necrosis are intermixed. Fully dynamic PET may improve accuracy but scan...

In vivo and in vitro characterization of [{sup 18}F]-FE-(+)-DTBZ as a tracer for beta-cell mass

Energy Technology Data Exchange (ETDEWEB)

Eriksson, Olof [Division of Radiology, Department of Oncology, Radiology and Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden)], E-mail: olof.eriksson@radiol.uu.se; Jahan, Mahabuba [Department of Clinical Neuroscience, Karolinska Institute, Section of Psychiatry, Karolinska Hospital, 171 76, Stockholm (Sweden); Johnstroem, Peter [Department of Clinical Neuroscience, Karolinska Institute, Section of Psychiatry, Karolinska Hospital, 171 76, Stockholm (Sweden); CNS and Pain Control, AstraZeneca R and D, 151 36, Soedertaelje (Sweden); Korsgren, Olle [Department of Oncology, Radiology and Clinical Immunology, Division of Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden); Sundin, Anders [Division of Radiology, Department of Oncology, Radiology and Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden); Department of Radiology, Karolinska University Hospital, 171 76, Stockholm (Sweden); Halldin, Christer [Department of Clinical Neuroscience, Karolinska Institute, Section of Psychiatry, Karolinska Hospital, 171 76, Stockholm (Sweden); Johansson, Lars [Division of Radiology, Department of Oncology, Radiology and Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden); AstraZeneca R and D, 431 50, Moelndal (Sweden)

2010-04-15

Introduction: The positron emission tomography (PET) tracer 9-[{sup 18}F]fluoroethyl-(+)-dihydrotetrabenazine ([{sup 18}F]-FE-(+)-DTBZ) is a potential candidate for quantifying beta-cell mass in vivo. The purpose was to investigate in vitro and in vivo utility of this tracer for the assessment of beta-cell mass. Methods: Three pigs were intravenously administered [{sup 18}F]-FE-(+)-DTBZ and examined by PET/computed tomography. Binding parameters were estimated by kinetic modeling. In vitro k{sub D} and B{sub max} were determined by saturation binding studies of endocrine and exocrine human tissue homogenates. In vitro pancreatic uptake was determined by tissue autoradiography with pancreases from patients with types 1 (T1DM) and 2 diabetes mellitus (T2DM) and healthy controls. Results: [{sup 18}F]-FE-(+)-DTBZ had a k{sub D} of 3.5{+-}1.0 nM, a B{sub max} of 382{+-}108 fmol/mg protein and a specificity of 89{+-}1.8% in islet homogenates. The total exocrine uptake was lower and 65% was nondisplaceable. No uptake difference was observed in pancreatic tissue slices from patients with T1DM, T2DM or healthy controls. The in vivo porcine pancreatic uptake reached a peak of standardized uptake value (SUV) of 2.8 with a low distribution volume ratio in all animals. Moderate to high tracer uptake was identified in the bile system and in bone. Conclusions: [{sup 18}F]-FE-(+)-DTBZ binds to vesicular monoamine transporter 2 (VMAT2) with high specificity in pure islet tissue in vitro. However, there is high nondisplaceable binding to exocrine tissue. In addition, in vivo tracer metabolism and dehalogenation result in severe underestimation of porcine pancreatic VMAT2 expression and BCM. The results do not support [{sup 18}F]-FE-(+)-DTBZ as a suitable tracer for in vivo beta-cell imaging.

Measurements of waste tank passive ventilation rates using tracer gases

International Nuclear Information System (INIS)

Huckaby, J.L.; Olsen, K.B.; Sklarew, D.S.; Evans, J.C.; Remund, K.M.

1997-09-01

This report presents the results of ventilation rate studies of eight passively ventilated high-level radioactive waste tanks using tracer gases. Head space ventilation rates were determined for Tanks A-101, AX-102, AX-103, BY-105, C-107, S-102, U-103, and U-105 using sulfur hexafluoride (SF 6 ) and/or helium (He) as tracer gases. Passive ventilation rates are needed for the resolution of several key safety issues. These safety issues are associated with the rates of flammable gas production and ventilation, the rates at which organic salt-nitrate salt mixtures dry out, and the estimation of organic solvent waste surface areas. This tracer gas study involves injecting a tracer gas into the tank headspace and measuring its concentration at different times to establish the rate at which the tracer is removed by ventilation. Tracer gas injection and sample collection were performed by SGN Eurisys Service Corporation and/or Lockheed Martin Hanford Corporation, Characterization Project Operations. Headspace samples were analyzed for He and SF 6 by Pacific Northwest National Laboratory (PNNL). The tracer gas method was first demonstrated on Tank S-102. Tests were conducted on Tank S-102 to verify that the tracer gas was uniformly distributed throughout the tank headspace before baseline samples were collected, and that mixing was sufficiently vigorous to maintain an approximately uniform distribution of tracer gas in the headspace during the course of the study. Headspace samples, collected from a location about 4 in away from the injection point and 15, 30, and 60 minutes after the injection of He and SF 6 , indicated that both tracer gases were rapidly mixed. The samples were found to have the same concentration of tracer gases after 1 hour as after 24 hours, suggesting that mixing of the tracer gas was essentially complete within 1 hour

Predicting the kinetics of chelating agents in man from animal data

International Nuclear Information System (INIS)

Durbin, P.W.; Schmidt, C.T.

1989-01-01

Published data were collected on clearance of 82Br, 24Na, inulin, and the ligands CaNa2-EDTA and CaNa3-DTPA from plasma of rats, dogs, and adult men. Data were restructured to a common base and reanalyzed using a two-compartment open-system kinetic model with an outlet from plasma to urinary excretion or from interstitial fluid to deposition in tissues. This was used to obtain transfer rates, distribution volumes, renal clearance, tracer content of interstitial fluid, and cumulative urinary excretion. The validity of the approach was demonstrated by good agreement of the calculated distribution volumes and renal clearances of the selected tracers with published values obtained by other analytical methods. The values of the parameters of the plasma curves and the transfer rates for EDTA and DTPA in the animals were combined with physiological data to evaluate the kinetic parameters of those substances in man. The human kinetic parameters of the ligands predicted from rat or dog data differed, on the average, from the values calculated from human data by +/- 13 and +/- 38%, respectively. The effective concentration of EDTA or DTPA in body fluids from time of injection to complete excretion and the mean concentration for the first 360 min after injection was calculated to be about four times greater in man than in rats and 3.5 times greater than in dogs for equimolar amounts injected. Based on the pharmacokinetics of DTPA, chelation therapy immediately after an actinide accident involving inhalation or extensive skin damage will be more efficient and more effective if a fraction of the standard clinical ZnNa3-DTPA dosage is administered every few hours instead of as a single daily injection

Evaluation of Positron Emission Tomographic Tracers for Imaging of Papillomavirus-Induced Tumors in Rabbits

Directory of Open Access Journals (Sweden)

Sonja Probst

2014-01-01

Full Text Available In this study, simultaneous positron emission tomography (PET/magnetic resonance (MR imaging was employed to evaluate the feasibility of the PET tracers 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG, 11C-choline, and 18F-fluorothymidine (18F-FLT to detect papillomavirus-induced tumors in an established rabbit model system. The combined PET/MR allowed the analysis of tracer uptake of the tumors using the morphologic information acquired by MR. New Zealand White rabbits were infected with cottontail rabbit papillomavirus genomes and were imaged for up to 10 months with a simultaneous PET/MR system during the course of infection. The uptake characteristics of the PET tracers 11C-choline and 18F-FLT of tumors and reference tissues were examined relative to the clinical standard, 18F-FDG. Tracer biodistribution of various organs was measured by gamma-counting after the last PET scan and compared to the in vivo PET/MR 18F-FDG uptake. Increased tracer uptake was found 2 months postinfection in primary tumors with 18F-FDG and 11C-choline, whereas 18F-FLT failed to detect the tumors at all measured time points. Our data show that the PET tracer 18F-FDG is superior for imaging papillomavirus-induced tumors in rabbits compared to 11C-choline and 18F-FLT. However, 11C-choline imaging, which has previously been applied to detect various tumor entities in patients, appears to be an alternative to 18F-FDG.

Nanoparticle tracers in calcium carbonate porous media

KAUST Repository

Li, Yan Vivian; Cathles, Lawrence M.; Archer, Lynden A.

2014-01-01

the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles

Is bone equally responsive to calcium and vitamins D intake from food vs. supplements? Use of 41Ca tracer kinetic model

Science.gov (United States)

Background: Few interventions directly compare equivalent calcium and vitamin D from dairy vs. supplements on the same bone outcomes. The radioisotope calcium-41 (41Ca) holds promise as a tracer method to directly measure changes in bone resorption with differing dietary interventions. Objective: U...

Using predictive uncertainty analysis to optimise tracer test design and data acquisition

Science.gov (United States)

Wallis, Ilka; Moore, Catherine; Post, Vincent; Wolf, Leif; Martens, Evelien; Prommer, Henning

2014-07-01

processes, followed by methane. Temperature data was assessed as the least informative of the solute tracers. However, taking costs of data acquisition into account, it could be shown that temperature data when used in conjunction with other tracers was a valuable and cost-effective marker species due to temperatures low cost to worth ratio. In contrast, the high costs of acquisition of methane data compared to its muted worth, highlighted methanes unfavourable return on investment. Areas of optimal monitoring bore position as well as optimal numbers of bores for the investigated injection site were also established. The proposed tracer test optimisation is done through the application of common use groundwater flow and transport models in conjunction with publicly available tools for predictive uncertainty analysis to provide modelers and practitioners with a powerful yet efficient and cost effective tool which is generally applicable and easily transferrable from the present study to many applications beyond the case study of injection of treated CSG produced water.

Chemotherapeutic agent and tracer composition and use thereof

International Nuclear Information System (INIS)

Babb, A. L.

1985-01-01

A therapeutic composition suitable for extracorporeal treatment of whole blood comprises a dialyzable chemotherapeutic agent and a dialyzable fluorescable tracer means. The removal rate of the fluorescable tracer compound from treated blood during hemodialysis is a function of the removal rate of unreacted chemotherapeutic agent present. The residual chemotherapeutic agent concentration after hemodialysis is ascertained by measuring the concentration of the fluorescable tracer compound in a dialysate using fluorometric techniques

PET tracers for somatostatin receptor imaging of neuroendocrine tumors

DEFF Research Database (Denmark)

Johnbeck, Camilla Bardram; Knigge, Ulrich; Kjær, Andreas

2014-01-01

Neuroendocrine tumors have shown rising incidence mainly due to higher clinical awareness and better diagnostic tools over the last 30 years. Functional imaging of neuroendocrine tumors with PET tracers is an evolving field that is continuously refining the affinity of new tracers in the search...... these PET tracers further....

Dispersion of dissolved tracers released at the seafloor

International Nuclear Information System (INIS)

Kupferman, S.L.; Moore, D.E.

1983-01-01

The authors present scenarios that describe the temporal and spatial development of a concentration field of a dissolved tracer released at the seafloor for one Pacific and two Atlantic study areas. The scenarios are closely tied to available data by means of simple analytical models, and they proceed in stages from short time and space scales in the immediate vicinity of a release point to those scales characteristic of entire ocean basins. They introduce and discuss the concepts of internal mixing time and residence time in the benthic mixed layer, which are useful for developing an intuitive feeling for the behavior of a tracer. They also introduce the concept of domain of occupation, which is useful in drawing distinctions between mixing and stirring in the ocean. From this study it is apparent that reliable estimation of mixing will require careful consideration of the dynamics of the eddy fields in the ocean. In addition they urgently need more information that relates isopycnal structure and bottom topography to local near-bottom circulation

Water tracers in the general circulation model ECHAM

International Nuclear Information System (INIS)

Hoffmann, G.; Heimann, M.

1993-01-01

We have installed a water tracer model into the ECHAM General Circulation Model (GCM) parameterizing all fractionation processes of the stable water isotopes ( 1 H 2 18 O and 1 H 2 H 16 O). A five year simulation was performed under present day conditions. We focus on the applicability of such a water tracer model to obtain information about the quality of the hydrological cycle of the GCM. The analysis of the simulated 1 H 2 18 O composition of the precipitation indicates too weak fractionated precipitation over the Antarctic and Greenland ice sheets and too strong fractionated precipitation over large areas of the tropical and subtropical land masses. We can show that these deficiencies are connected with problems of model quantities such as the precipitation and the resolution of the orography. The linear relationship between temperature and the δ 18 O value, i.e. the Dansgaard slope, is reproduced quite well in the model. The slope is slightly too flat and the strong correlation between temperature and δ 18 O vanishes at very low temperatures compared to the observations. (orig.)

Development of a downhole tool measuring real-time concentration of ionic tracers and pH in geothermal reservoirs

Science.gov (United States)

Hess, Ryan F.; Boyle, Timothy J.; Limmer, Steven; Yelton, William G.; Bingham, Samuel; Stillman, Greg; Lindblom, Scott; Cieslewski, Grzegorz

2014-06-01

For enhanced or Engineered Geothermal Systems (EGS) geothermal brine is pumped to the surface via the production wells, the heat extracted to turn a turbine to generate electricity, and the spent brine re-injected via injection wells back underground. If designed properly, the subsurface rock formations will lead this water back to the extraction well as heated brine. Proper monitoring of these geothermal reservoirs is essential for developing and maintaining the necessary level of productivity of the field. Chemical tracers are commonly used to characterize the fracture network and determine the connectivity between the injection and production wells. Currently, most tracer experiments involve injecting the tracer at the injection well, manually collecting liquid samples at the wellhead of the production well, and sending the samples off for laboratory analysis. While this method provides accurate tracer concentration data at very low levels of detection, it does not provide information regarding the location of the fractures which were conducting the tracer between wellbores. Sandia is developing a high-temperature electrochemical sensor capable of measuring tracer concentrations and pH downhole on a wireline tool. The goal of this effort is to collect real-time pH and ionic tracer concentration data at temperatures up to 225 °C and pressures up to 3000 psi. In this paper, a prototype electrochemical sensor and the initial data obtained will be presented detailing the measurement of iodide tracer concentrations at high temperature and pressure in a newly developed laboratory scale autoclave.

Tracer applications in oil reservoirs in Brazil

International Nuclear Information System (INIS)

Moreira, R.M.; Ferreira Pinto, A.M.

2004-01-01

Radiotracer applications in oil reservoirs in Brazil started in 1997 at the request of the State Oil Company (Petrobras) at the Carmoplois oilfield. 1 Ci of HTO was injected in a regular five-spot plot and the results obtained were quite satisfactory. Shortly after this test one other request asked for distinguishing the contribution of different injection wells to a production well. It was then realized that other tracers should be available. As a first choice 35 SCN - has been selected since it could be produced at CDTN. An alternative synthesis path was defined which shortened post-irradiation manipulations. The tracer was tested in core samples and a field injection, simultaneously with HTO, was carried out at the Buracica field; again the HTO performed well but 35 SCN - showed up well ahead. Presently the HTO applications are being done on a routine basis. All in all, four tests were performed (some are still ongoing), and the detection limits for both 3 H and 35 S were optimized by refining the sample preparation stage. Lanthanide complexes used as activable tracers are also an appealing option, however core tests performed so far with La-, Ce- and Eu-EDTA indicated some delay of the tracer, so other complexants such as DOTA are to be tried in further laboratory tests and in a field application. Thus, a deeper understanding of their complexation chemistry and carefully conducted tests must be performed before lanthanide complexes can be qualified as reliable oil reservoir tracers. More recently, Petrobras has been asking for partitioning tracers intended for SOR measurement

Kinetic modeling of receptor-ligand binding applied to positron emission tomographic studies with neuroleptic tracers

Energy Technology Data Exchange (ETDEWEB)

Logan, J; Wolf, A P; Shiue, C Y; Fowler, J S

1987-01-01

Positron emission tomography (PET) with labeled neuroleptics has made possible the study of neurotransmitter-receptor systems in vivo. In this study we investigate the kinetics of the 3,4-dihydroxyphenylethylamine (dopamine) receptor-ligand binding using PET data from a series of experiments in the baboon with the /sup 18/F-labeled drugs spiperone, haloperidol, and benperidol. Models used to describe these systems are based on first-order kinetics which applies at high specific activity (low receptor occupancy). The parameters governing the uptake and loss of drug from the brain were found by fitting PET data from regions with little or no receptor concentration (cerebellum) and from experiments in which specific binding was blocked by pretreatment with the drug (+)-butaclamol. Receptor constants were determined by fitting data from receptor-containing structures. Correcting the arterial plasma activities (the model driving function) for the presence of drug metabolites was found to be important in the modeling of these systems.

Tracer dispersion in planar multipole flows

International Nuclear Information System (INIS)

Koplik, J.; Redner, S.; Hinch, E.J.

1994-01-01

We study the motion of passive Brownian tracer particles in steady two-dimensional potential flows between sources and sinks. Our primary focus is understanding the long-time properties of the transit time probability distribution for the tracer to reach the sink p(t) and the influence of the flow geometry on this probability. A variety of illustrative case studies is considered. For radial potential flow in an annular region, competition between convection and diffusion leads to nonuniversal decay of the transit time probability. Dipolar and higher multipole flows are found to exhibit generic features, such as a power-law decay in p(t) with an exponent determined by the multipole moment, an exponential cutoff related to stagnation points, and a ''shoulder'' in p(t) that is related to reflection from the system boundaries. For spatially extended sinks, it is also shown that the spatial distribution of the collected tracer is independent of the overall magnitude of the flow field and that p(t) decays as a power law with a geometry-dependent exponent. Our results may offer the possibility of using tracer measurements to characterize the flow geometry of porous media

New radioactive tracers can help find cause of jaundice

International Nuclear Information System (INIS)

Carrard, G.

1987-01-01

Radioactive tracers for the investigation of a condition known as persistent jaundice of the newborn, have been designed, prepared and tested at ANSTO. The tracers are chemical compounds of the radioactive elements gallium-67 and indium-111. They given lower radiation doses than the conventional radioactive tracer, iodine-131, used in these studies

Benefits of important industrial tracer applications in the GDR

International Nuclear Information System (INIS)

Leonhardt, J.W.; Goeldner, R.; Koennecke, H.G.; Kupsch, H.; Luther, D.; Otto, R.; Reinhardt, R.; Ulrich, H.

1990-01-01

Tracers can be used to label substances or objects in order to discriminate between them, to follow their movement, to record changes of concentration and distribution between phases, etc. The main advantages of tracer investigations are the contactless recording of signals without influencing the observed process (also under rigorous operation conditions), the high detection sensitivity, the large number of available tracer nuclides (problems of all branches of industry can be solved) and the fact that tracer investigation can be carried out on operating production units, so that they provide valuable checks of the validity of design and process data. The cost-to-benefit ratio can be as low as 1:50. In the following some selected examples of tracer applications and their benefits will be presented. (orig./BBR) [de

Estimation of time-variable fast flow path chemical concentrations for application in tracer-based hydrograph separation analyses

Science.gov (United States)

Kronholm, Scott C.; Capel, Paul D.

2016-01-01

Mixing models are a commonly used method for hydrograph separation, but can be hindered by the subjective choice of the end-member tracer concentrations. This work tests a new variant of mixing model that uses high-frequency measures of two tracers and streamflow to separate total streamflow into water from slowflow and fastflow sources. The ratio between the concentrations of the two tracers is used to create a time-variable estimate of the concentration of each tracer in the fastflow end-member. Multiple synthetic data sets, and data from two hydrologically diverse streams, are used to test the performance and limitations of the new model (two-tracer ratio-based mixing model: TRaMM). When applied to the synthetic streams under many different scenarios, the TRaMM produces results that were reasonable approximations of the actual values of fastflow discharge (±0.1% of maximum fastflow) and fastflow tracer concentrations (±9.5% and ±16% of maximum fastflow nitrate concentration and specific conductance, respectively). With real stream data, the TRaMM produces high-frequency estimates of slowflow and fastflow discharge that align with expectations for each stream based on their respective hydrologic settings. The use of two tracers with the TRaMM provides an innovative and objective approach for estimating high-frequency fastflow concentrations and contributions of fastflow water to the stream. This provides useful information for tracking chemical movement to streams and allows for better selection and implementation of water quality management strategies.

Meteorological conditions at the release site during the two tracer experiments

DEFF Research Database (Denmark)

Gryning, Sven-Erik; Batchvarova, E.; Schneiter, D.

1998-01-01

The state of the boundary layer at the release site during the two tracer experiments is described, based on measurements of atmospheric turbulence carried our by a sonic anemometer, profiles of horizontal and vertical wind by a SODAR as well as frequent radiosonde releases. The boundary layer...... height is derived from radiosoundings, modelled and discussed. The study is meant as background for discussions of the tracer behaviour near the release site, and possible influence of the local meteorology at the release site on the long-range dispersion. The difference in the initial mese...... model development. It is concluded that the micrometeorological measurements are very important as background information for the understanding of plume behaviour on small as well as long scales. (C) 1998 Elsevier Science Ltd. All rights reserved....

Fluorinated tracers for imaging cancer with positron emission tomography

International Nuclear Information System (INIS)

Couturier, Olivier; Chatal, Jean-Francois; Luxen, Andre; Vuillez, Jean-Philippe; Rigo, Pierre; Hustinx, Roland

2004-01-01

2-[ 18 F]fluoro-2-deoxy-d-glucose (FDG) is currently the only fluorinated tracer used in routine clinical positron emission tomography (PET). Fluorine-18 is considered the ideal radioisotope for PET imaging owing to the low positron energy (0.64 MeV), which not only limits the dose rate to the patient but also results in a relatively short range of emission in tissue, thereby providing high-resolution images. Further, the 110-min physical half-life allows for high-yield radiosynthesis, transport from the production site to the imaging site and imaging protocols that may span hours, which permits dynamic studies and assessment of potentially fairly slow metabolic processes. The synthesis of fluorinated tracers as an alternative to FDG was initially tested using nucleophilic fluorination of the molecule, as performed when radiolabelling with iodine-124 or bromide-76. However, in addition to being long, with multiple steps, this procedure is not recommended for bioactive molecules containing reactive groups such as amine or thiol groups. Radiochemical yields are also often low. More recently, radiosynthesis from prosthetic group precursors, which allows easier radiolabelling of biomolecules, has led to the development of numerous fluorinated tracers. Given the wide availability of 18 F, such tracers may well develop into important routine tracers. This article is a review of the literature concerning fluorinated radiotracers recently developed and under investigation for possible PET imaging in cancer patients. Two groups can be distinguished. The first includes ''generalist'' tracers, i.e. tracers amenable to use in a wide variety of tumours and indications, very similar in this respect to FDG. These are tracers for non-specific cell metabolism, such as protein synthesis, amino acid transport, nucleic acid synthesis or membrane component synthesis. The second group consists of ''specific'' tracers for receptor expression (i.e. oestrogens or somatostatin), cell

Comment on ‘Information hidden in the velocity distribution of ions and the exact kinetic Bohm criterion’

Science.gov (United States)

Mustafaev, A. S.; Sukhomlinov, V. S.; Timofeev, N. A.

2018-03-01

This Comment is devoted to some mathematical inaccuracies made by the authors of the paper ‘Information hidden in the velocity distribution of ions and the exact kinetic Bohm criterion’ (Plasma Sources Science and Technology 26 055003). In the Comment, we show that the diapason of plasma parameters for the validity of the theoretical results obtained by the authors was defined incorrectly; we made a more accurate definition of this diapason. As a result, we show that it is impossible to confirm or refute the feasibility of the Bohm kinetic criterion on the basis of the data of the cited paper.

A novel fluorescent retrograde neural tracer: cholera toxin B conjugated carbon dots

Science.gov (United States)

Zhou, Nan; Hao, Zeyu; Zhao, Xiaohuan; Maharjan, Suraj; Zhu, Shoujun; Song, Yubin; Yang, Bai; Lu, Laijin

2015-09-01

tracers. Electronic supplementary information (ESI) available: PL spectra of CTB; absorption spectra of dialysate; fluorescence signal and immunohistochemical staining of CTB-CDs in L4 DRG. See DOI: 10.1039/c5nr04361a

COMPARISON OF THREE TRACER TESTS AT THE RAFT RIVER GEOTHERMAL SITE

Energy Technology Data Exchange (ETDEWEB)

Earl D Mattson; Mitchell Plummer; Carl Palmer; Larry Hull; Samantha Miller; Randy Nye

2011-02-01

Three conservative tracer tests have been conducted through the Bridge Fault fracture zone at the Raft River Geothermal (RRG) site. All three tests were conducted between injection well RRG-5 and production wells RRG-1 (790 m distance) and RRG-4 (740 m distance). The injection well is used during the summer months to provide pressure support to the production wells. The first test was conducted in 2008 using 136 kg of fluorescein tracer. Two additional tracers were injected in 2010. The first 2010 tracer injected was 100 kg fluorescein disodium hydrate salt on June, 21. The second tracer (100 kg 2,6-naphthalene disulfonic acid sodium salt) was injected one month later on July 21. Sampling of the two productions wells is still being performed to obtain the tail end of the second 2010 tracer test. Tracer concentrations were measured using HPLC with a fluorescence detector. Results for the 2008 test, suggest 80% tracer recover at the two production wells. Of the tracer recovered, 85% of tracer mass was recovered in well RRG-4 indicating a greater flow pathway connection between injection well and RRG-4 than RRG-1. Fluorescein tracer results appear to be similar between the 2008 and 2010 tests for well RRG-4 with peak concentrations arriving approximately 20 days after injection despite the differences between the injection rates for the two tests (~950 gpm to 475 gpm) between the 2008 and 2010. The two 2010 tracer tests will be compared to determine if the results support the hypothesis that rock contraction along the flow pathway due to the 55 oC cooler water injection alters the flow through the ~140 oC reservoir.

Tracer verification and monitoring of containment systems (II)

International Nuclear Information System (INIS)

Williams, C.V.; Dunn, S.D.; Lowry, W.E.

1997-01-01

A tracer verification and monitoring system, SEAtrace trademark, has been designed and field tested which uses gas tracers to evaluate, verify, and monitor the integrity of subsurface barriers. This is accomplished using an automatic, rugged, autonomous monitoring system combined with an inverse optimization code. A gaseous tracer is injected inside the barrier and an array of wells outside the barrier are monitored. When the tracer gas is detected, a global optimization code is used to calculate the leak parameters, including leak size, location, and when the leak began. The multipoint monitoring system operates in real-time, can be used to measure both the tracer gas and soil vapor contaminants, and is capable of unattended operation for long periods of time (months). The global optimization code searches multi-dimensional open-quotes spaceclose quotes to find the best fit for all of the input parameters. These parameters include tracer gas concentration histories from multiple monitoring points, medium properties, barrier location, and the source concentration. SEAtrace trademark does not attempt to model all of the nuances associated with multi-phase, multi-component flow, but rather, the inverse code uses a simplistic forward model which can provide results which are reasonably accurate. The system has calculated leak locations to within 0.5 meters and leak radii to within 0.12 meters

The application of mathematical models for the evaluation of radioactive tracer tests carried out in South Africa

International Nuclear Information System (INIS)

Snyman, G.C.; Smith, S.W.

1975-12-01

The application of mathematical models to evaluate tracer experiments is illustrated by examples of tests done in a variety of industrial plants, using radioactive tracers. Two basic models, the axial mixing model and the perfectly mixed tank model, as well as various applicational techniques, are described. It is concluded that many processes can be simulated to various degrees of accuracy by using the basic models, and that both quantitative and qualitative information can be obtained about the process [af

First technical report about tracer applications to processes assessment in a portable water potabilizing plant

International Nuclear Information System (INIS)

Suarez Antola, R.; Giosa Porley, P.

1996-03-01

Radioactive and fluorescent tracers were applied to measure the distribution of residence times in each of the four subsystems of a portable water purifying plant: the mechanical flocculation unit, the hydraulic flocculation unit, the sedimentation unit, and the sand filter. This report begins by a revision of the physicochemical processes produced in each of the above mentioned subsystems, connected in series. Then a mathematical model of residence time distribution for each unit is constructed, with free parameters that can be estimated from the experimental results obtained with tracers. Tracer methodology for this kind of field experiment is reviewed. Their possible short comes are briefly discussed for each of the intended tracers. The tracer experiments done with rhodamine and uranine are described. The experimental results are reported and the residence time distributions obtained with different tracers were carefully compared. In order to make the field experiments, five different values of global water flow were sustained, pumping in steady state: two under the nominal (design) value, two above the design flow and one equal to the nominal water flow. The model parameters were determined using a software package, D TR , made in France and supplied by the IAEA in the framework of the project. It was discovered that the diffuser in the sedimentation unit was not working as intended, and some guidelines for its re-design could be given to the process engineers. Also, process engineers received information about some amount of by-pass flow and death zones, as well as their variations with plant's global water flow

EGS in sedimentary basins: sensitivity of early-flowback tracer signals to induced-fracture parameters

Science.gov (United States)

Karmakar, Shyamal; Ghergut, Julia; Sauter, Martin

2015-04-01

Artificial-fracture design, and fracture characterization during or following stimulation treatment is a central aspect of many EGS ('enhanced' or 'engineered' geothermal system) projects. During the creation or stimulation of an EGS, the injection of fluids, followed by flowback and production stages offers the opportunity for conducting various tracer tests in a single-well (SW) configuration, and given the typical operational and time limitations associated with such tests, along with the need to assess treatment success in real time, investigators mostly favour using short-time tracer-test data, rather than awaiting long-term 'tailings' of tracer signals. Late-time tracer signals from SW injection-flowback and production tests have mainly been used for the purpose of multiple-fracture inflow profiling in multi-layer reservoirs [1]. However, the potential of using SW short-term tracer signals for fracture characterization [2, 3] remained little explored as yet. Dealing with short-term flowback signals, we face a certain degree of parameter interplay, leading to ambiguity in fracture parameter inversion from the measured signal of a single tracer. This ambiguity can, to a certain extent, be overcome by - combining different sources of information (lithostratigraphy, and hydraulic monitoring) in order to constrain the variation range of hydrogeologic parameters (matrix and fracture permeability and porosity, fracture size), - using different types of tracers, such as conservative tracer pairs with contrasting diffusivity, or tracers pairs with contrasting sorptivity onto target surfaces. Fracture height is likely to be constrained by lithostratigraphy, while fracture length is supposed to be determinable from hydraulic monitoring (pressure recordings); the flowback rate can be assumed as a known (measurable) quantity during individual-fracture flowback. This leaves us with one or two unknown parameters to be determined from tracer signals: - the transport

Suitability of tracers; Eignung von Tracern

Energy Technology Data Exchange (ETDEWEB)

Klotz, D. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany). Inst. fuer Hydrologie

1999-02-01

Hydrological tracer techniques are a means of making statements on the direction and speed of underground water. One of the simpler tasks is to find out whether there is hydrological communication between two given points. This requires a determination of the direction of flow, which places less exacting demands on the properties of the tracer than does the task of determining the flow velocity of underground water. Tracer methods can serve to infer from flow velocity the distance (flow) velocity, which is defined as the ratio between the distance between two points located in flow direction and the actual time it takes water to flow from one to the other. [Deutsch] Mit Hilfe der hydrologischen Markierungstechniken koennen Aussagen ueber die Richtung und die Geschwindigkeit von Bewegungen des unterirdischen Wassers gemacht werden. Der einfachere Fall liegt vor, wenn festgestellt werden soll, ob zwischen zwei Punkten eine hydrologische Verbindung besteht. Bei dieser Fliessrichtungsbestimmung sind die Forderungen an die Eigenschaften der einzusetzenden Tracer geringer als bei der Bestimmung der Geschwindigkeit des unterirdischen Wassers. Von den Geschwindigkeiten des unterirdischen Wassers ist die Abstands-(Fliess)geschwindigkeit, die definiert ist durch das Verhaeltnis aus dem Abstand und der wahren Fliesszeit zwischen zwei in Bewegungsrichtung gelegenen Punkten, durch Tracermethoden zu bestimmen. (orig.)

Pipeline leak detection using volatile tracers

International Nuclear Information System (INIS)

Thompson, G.M.; Golding, R.D.

1993-01-01

A method of leak detection for underground storage tanks and pipelines adds volatile tracers to the products in the tanks and analyzes the surrounding shallow soil gases for tracer vapors. This method has several advantages: the success of the test is not limited by the size and structural design of the vessels, tanks can be tested at any fill level without taking the tank out of service, the location of a leak along a pipeline is clearly marked by the location of the tracer, and liquid leaks as small as 0.2 liters per hour (lph) can be detected. A limitation is: the backfill material must have some degree of air permeability in the zone above the water table. Several field tests document the success achieved using this method. A tracer leak detection system was installed at Homestead AFB after several other testing methods failed to locate a leak at a valve pit location along approximately 4 kilometers of fuel transfer piping. The leak was detected to the side of the valve pit at a depth of approximately 2.5 meters below the ground surface. Another installation of Edwards AFB involved the collection of 415 soil gas samples along approximately 3,050 meters of 15.25-centimeter fiberglass pipeline. Fourteen separate leaks were detected

Determination of the self purification of streams using tracers

International Nuclear Information System (INIS)

Salviano, J.S.

1982-04-01

A methodology for the 'in situ' evaluation of the self purification of streams is discussed. It consists of the simultaneous injection of two tracers into the stream. One of the tracers is oxidized by biochemical processes. It can be either artificially supplied to the stream or a naturally present component can be used. This tracer is used for the determination of the self purification parameters. The other tracer is conservative and allows for the hydrodynamic effects. Tests have been carried out in two streams with quite different hydrodynamic and physicochemical conditions. In the first stream, with a flow-rate of about 0.9 m 3 /s, urea was used as the nonconservative tracer. In the other stream, which had a flow-rate of about 5 m 3 /s, only a radioactive tracer has been used, and the rate of biochemical oxidation has been determined from BOD measurements. Calculations have been implemented on a digital computer. In both cases it was found that the reoxygenation rate is more conveniently determined by empirical formulas. Results from both tests have been deemed realistic by comparison with similar experiments. (Author) [pt

Wirelessly powered micro-tracer enabled by miniaturized antenna and microfluidic channel

International Nuclear Information System (INIS)

Duan, G; Zhao, X; Seren, H R; Chen, C; Zhang, X

2015-01-01

A miniaturized antenna, 380μm by 380μm in size, was fabricated and integrated with a commercialized passive RFID chip to form a micro-tracer, whose size was 2mm by 1mm in total. The micro-tracer was wirelessly powered and interrogated by a single layer spiral reader antenna through near field coupling. To maximize the working distance, the resonant frequency of micro-tracer and reader antenna were matched at 840MHz. Due to the ultra small size of the tracer antenna, power transfer efficiency decreased dramatically as the distance between tracer antenna and reader antenna increased, thus the working distance of the microtracer was limited within 1mm. To achieve massive operation of the micro-tracer, a microfluidic platform was fabricated with in channel focusing and separation. Acrylic sheets were laser cut to define the channel and cover structure, then bonded together layer by layer with a glass substrate, on which reader antenna was integrated. Pump oil was used as the fluidic media carrying the micro-tracer flowing inside the microfluidic channel. The wireless power transfer and real-time communication was demonstrated with the micro-tracer flowing above the reader antenna, as the ID of the micro-tracer was retrieved and displayed on a computer screen. (paper)

Double tracer experiments to evaluate atmospheric transport and dose models

International Nuclear Information System (INIS)

Nielsen, S.P.; Gryning, S.-E.; Thykier-Nielsen, S.; Karlberg, O.; Lyck, E.

1986-05-01

Two tracers, sulphurhexafluoride (SF 6 ) and radioactive noble gases, were released simultaneously from a 110-m stack and detected downwind at distances of 3-4 km. The experiments were made at the Swedish nuclear power plant Ringhals in 1981. The radioactive tracer was routine emissions from unit 1 (BWR). The one-hour measurements yielded crosswind profiles at ground level of SF 6 -concentrations and of gamma radiation from the plume. The measured profiles were compared to profiles calculated with computer models. The comparison showed that the models sometimes underestimate and sometimes overestimate the results, which seems to indicate that the models within their limited accuracy yield unbiased results. The ratios between measured and calculated values range from 0.2 to 3. The measurements revealed a surplus of gamma radiations from the noble gas daughters compared to those from the gases. This was interpreted as due to ground desposition and the estimated deposition velocities range from 2 to 10 cm/s. The meteorological conditions were monitored from a 100-m meteorological tower and from an 11-m mast. Measurements were made of wind speed, wind direction, and temperatures at different heights, and during each experiment a mini-radiosonde was released giving information on a possible inversion layer. The SF 6 -tracer was injected to the stack prior to the experiments. Air-samples were collected downwind in plastic bags by radio-controlled sampling units. The SF 6 -concentrations in the bags were determined with gas chromatography. Measurements of the gamma radiation from the plume were made with ionisation chambers and GM-counters. Furthermore, a few mobile gamma spectrometers were available giving information on the unscattered gamma radiation, thereby permitting identification of the radioactive isotopes. The work was partly financed by the Nuclear Safety Board of the Swedish Utilities and by the Danish association of utilities in Jutland and on Funen, Elsam

Quantitative Visualization of Dynamic Tracer Transportation in the Extracellular Space of Deep Brain Regions Using Tracer-Based Magnetic Resonance Imaging

Science.gov (United States)

Hou, Jin; Wang, Wei; Quan, Xianyue; Liang, Wen; Li, Zhiming; Han, Hongbin; Chen, Deji

2017-01-01

Background This study assessed an innovative tracer-based magnetic resonance imaging (MRI) system to visualize the dynamic transportation of tracers in regions of deep brain extracellular space (ECS) and to measure transportation ability and ECS structure. Material/Methods Gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) was the chosen tracer and was injected into the caudate nucleus and thalamus. Real-time dynamic transportation of Gd-DTPA in ECS was observed and the results were verified by laser scanning confocal microscopy. Using Transwell assay across the blood-brain barrier, a modified diffusion equation was further simplified. Effective diffusion coefficient D* and tortuosity λ were calculated. Immunohistochemical staining and Western blot analysis were used to investigate the extracellular matrix contributing to ECS structure. Results Tracers injected into the caudate nucleus were transported to the ipsilateral frontal and temporal cortices away from the injection points, while both of them injected into the thalamus were only distributed on site. Although the caudate nucleus was closely adjacent to the thalamus, tracer transportation between partitions was not observed. In addition, D* and the λ showed statistically significant differences between partitions. ECS was shown to be a physiologically partitioned system, and its division is characterized by the unique distribution territory and transportation ability of substances located in it. Versican and Tenascin R are possible contributors to the tortuosity of ECS. Conclusions Tracer-based MRI will improve our understanding of the brain microenvironment, improve the techniques for local delivery of drugs, and highlight brain tissue engineering fields in the future. PMID:28866708

Quantitative Visualization of Dynamic Tracer Transportation in the Extracellular Space of Deep Brain Regions Using Tracer-Based Magnetic Resonance Imaging.

Science.gov (United States)

Hou, Jin; Wang, Wei; Quan, Xianyue; Liang, Wen; Li, Zhiming; Chen, Deji; Han, Hongbin

2017-09-03

BACKGROUND This study assessed an innovative tracer-based magnetic resonance imaging (MRI) system to visualize the dynamic transportation of tracers in regions of deep brain extracellular space (ECS) and to measure transportation ability and ECS structure. MATERIAL AND METHODS Gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) was the chosen tracer and was injected into the caudate nucleus and thalamus. Real-time dynamic transportation of Gd-DTPA in ECS was observed and the results were verified by laser scanning confocal microscopy. Using Transwell assay across the blood-brain barrier, a modified diffusion equation was further simplified. Effective diffusion coefficient D* and tortuosity λ were calculated. Immunohistochemical staining and Western blot analysis were used to investigate the extracellular matrix contributing to ECS structure. RESULTS Tracers injected into the caudate nucleus were transported to the ipsilateral frontal and temporal cortices away from the injection points, while both of them injected into the thalamus were only distributed on site. Although the caudate nucleus was closely adjacent to the thalamus, tracer transportation between partitions was not observed. In addition, D* and the λ showed statistically significant differences between partitions. ECS was shown to be a physiologically partitioned system, and its division is characterized by the unique distribution territory and transportation ability of substances located in it. Versican and Tenascin R are possible contributors to the tortuosity of ECS. CONCLUSIONS Tracer-based MRI will improve our understanding of the brain microenvironment, improve the techniques for local delivery of drugs, and highlight brain tissue engineering fields in the future.

Advancing Reactive Tracer Methods for Measurement of Thermal Evolution in Geothermal Reservoirs: Final Report

Energy Technology Data Exchange (ETDEWEB)

Mitchell A. Plummer; Carl D. Palmer; Earl D. Mattson; Laurence C. Hull; George D. Redden

2011-07-01

The injection of cold fluids into engineered geothermal system (EGS) and conventional geothermal reservoirs may be done to help extract heat from the subsurface or to maintain pressures within the reservoir (e.g., Rose et al., 2001). As these injected fluids move along fractures, they acquire heat from the rock matrix and remove it from the reservoir as they are extracted to the surface. A consequence of such injection is the migration of a cold-fluid front through the reservoir (Figure 1) that could eventually reach the production well and result in the lowering of the temperature of the produced fluids (thermal breakthrough). Efficient operation of an EGS as well as conventional geothermal systems involving cold-fluid injection requires accurate and timely information about thermal depletion of the reservoir in response to operation. In particular, accurate predictions of the time to thermal breakthrough and subsequent rate of thermal drawdown are necessary for reservoir management, design of fracture stimulation and well drilling programs, and forecasting of economic return. A potential method for estimating migration of a cold front between an injection well and a production well is through application of reactive tracer tests, using chemical whose rate of degradation is dependent on the reservoir temperature between the two wells (e.g., Robinson 1985). With repeated tests, the rate of migration of the thermal front can be determined, and the time to thermal breakthrough calculated. While the basic theory behind the concept of thermal tracers has been understood for some time, effective application of the method has yet to be demonstrated. This report describes results of a study that used several methods to investigate application of reactive tracers to monitoring the thermal evolution of a geothermal reservoir. These methods included (1) mathematical investigation of the sensitivity of known and hypothetical reactive tracers, (2) laboratory testing of novel

Using neural networks to describe tracer correlations

Directory of Open Access Journals (Sweden)

D. J. Lary

2004-01-01

Full Text Available Neural networks are ideally suited to describe the spatial and temporal dependence of tracer-tracer correlations. The neural network performs well even in regions where the correlations are less compact and normally a family of correlation curves would be required. For example, the CH4-N2O correlation can be well described using a neural network trained with the latitude, pressure, time of year, and methane volume mixing ratio (v.m.r.. In this study a neural network using Quickprop learning and one hidden layer with eight nodes was able to reproduce the CH4-N2O correlation with a correlation coefficient between simulated and training values of 0.9995. Such an accurate representation of tracer-tracer correlations allows more use to be made of long-term datasets to constrain chemical models. Such as the dataset from the Halogen Occultation Experiment (HALOE which has continuously observed CH4  (but not N2O from 1991 till the present. The neural network Fortran code used is available for download.

Tracer measurements compared to process data reconciliation in accordance with VDI 2048

International Nuclear Information System (INIS)

Hungerbuehler, Thomas; Langenstein, Magnus

2007-01-01

The feed water mass flow is the key measured variable used to determine the thermal reactor output in a nuclear power plant. Usually this parameter is recorded via venturi nozzles or orifice plates. The problem with both principles of measurement, however, is that an accuracy of below 1% cannot be reached. In the case of nuclear power plants and depending on the size of the plant, this corresponds to an electrical output of 4 MWel to 16 MWel. In order to make more accurate statements about the feed water amounts recirculated in the water-steam circuit, tracer measurements that offer an accuracy of up to 0.2% are used. A drawback of this method is that this measuring principle is suitable only for providing an instantaneous picture but does not provide continuous operating information about the feed water mass flow. Process data reconciliation based on VDI 2048 is a mathematical-statistic process that makes use of redundant process information. The uncertainty of reconciled feed water flow rates and the thermal reactor output calculated on this basis can be reduced to 0.4%. The overall process monitored continuously in this manner therefore provides hourly process information of a quality equal to that obtained with acceptance measurements. In the NPP Beznau both methods have been used in parallel to determine the feed water flow rates in 2004 (unit 1) and 2005 (unit 2). Comparison of the results shows that a high level of agreement is obtained between the results of the reconciliation and the results of the tracer measurements. For this reason it was decided that no future tracer measurements will be conducted anymore. A result of the findings of this comparison, a high level of acceptance of process data reconciliation based on VDI 2048 was achieved. (author)

Methods of 15N tracer research in biological systems

International Nuclear Information System (INIS)

Hirschberg, K.; Faust, H.

1985-01-01

The application of the stable isotope 15 N is of increasing importance in different scientific disciplines, especially in medicine, agriculture, and the biosciences. The close correlation between the growing interest and improvements of analytical procedures resulted in remarkable advances in the 15 N tracer technique. On the basis of the latest results of 15 N tracer research in life sciences and agriculture methods of 15 N tracer research in biological systems are compiled. The 15 N methodology is considered under three headings: Chemical analysis with a description of methods of sample preparation (including different separation and isolation methods for N-containing substances of biological and agricultural origin) and special procedures converting ammonia to molecular nitrogen. Isotopic analysis with a review on the most important methods of isotopic analysis of nitrogen: mass spectrometry (including the GC-MS technique), emission spectrometry, NMR spectroscopy, and other analytical procedures. 15 N-tracer techniques with a consideration of the role of the isotope dilution analysis as well as different labelling techniques and the mathematical interpretation of tracer data (modelling, N turnover experiments). In these chapters also sources of errors in chemical and isotopic analysis, the accuracy of the different methods and its importance on tracer experiments are discussed. Procedures for micro scale 15 N analysis and aspects of 15 N analysis on the level of natural abundance are considered. Furthermore some remarks on isotope effects in 15 N tracer experiments are made. (author)

Time-lapse Mise-á-la-Masse measurements and modeling for tracer test monitoring in a shallow aquifer

Science.gov (United States)

Perri, Maria Teresa; De Vita, Pantaleone; Masciale, Rita; Portoghese, Ivan; Chirico, Giovanni Battista; Cassiani, Giorgio

2018-06-01

The main goal of this study is to evaluate the reliability of the Mise-á-la-Masse (MALM) technique associated with saline tracer tests for the characterization of groundwater flow direction and velocity. The experimental site is located in the upper part of the Alento River alluvial plain (Campania Region, Southern Italy). In this paper we present the hydrogeological setting, the experimental setup and the relevant field results. Subsequently, we compare those data against the simulated results obtained with a 3D resistivity model of the test area, coupled with a model describing the Advection - Dispersion equation for continuous tracer injection. In particular, we calculate a series of 3D forward solutions starting from a reference model, all derived from electrical tomography results, but taking into consideration different values of mean flow velocity and directions. Each electrical resistivity 3D model is used to produce synthetic voltage maps for MALM surveys. Finally, the synthetic MALM voltage maps are compared with the ones measured in the field in order to assess the information content of the MALM dataset with respect to the groundwater field characteristics. The results demonstrate that the information content of the MALM data is sufficient to define important characteristics of the aquifer geometry and properties. This work shows how a combination of three-dimensional time-lapse modeling of flow, tracer transport and electrical current can substantially contribute towards a quantitative interpretation of MALM measurements during a saline tracer test. This approach can thus revive the use of MALM as a practical, low cost field technique for tracer test monitoring and aquifer hydrodynamic characterization.

Tracer kinetic studies of the low density lipoprotein metabolism in the fetal rat: An example for estimation of flux rates in the nonsteady state

International Nuclear Information System (INIS)

Plonne, D.; Schlag, B.; Winkler, L.; Dargel, R.

1990-01-01

To get insight into the low density lipoprotein (LDL)-apoB flux in the rat fetus near term and in the early postnatal period, homologous apoE-free 125I-labeled LDL was injected into the umbilical vein of the rat fetus immediately after Caesarean section. Since the serum LDL-apoB spontaneously declined after birth, a time-dependent two-pool model was used to calculate the flux rates in the neonate from the specific activities of LDL-apoB up to 15 h post partum. An approximate value of LDL-apoB flux in the fetus at birth was obtained by extrapolation of the kinetic data to the time of injection of the tracer. The data revealed that the turnover of LDL-apoB in the fetus (18.6 micrograms LDL-apoB/h per g body weight) exceeded that in the adult rat (0.4 microgram/h per g body weight) by at least one order of magnitude. Even 15 h after delivery, the LDL-apoB influx amounted to 2.5 micrograms/h per g body weight. The fractional catabolic rate of LDL-apoB in the fetus at term (0.39, h-1) slightly exceeded that in the adult animal (0.15, h-1) and reached the adult level within the first 3 h after birth and remained constant thereafter. In the rat fetus, LDL-apoB flux greatly exceeds that of VLDL-apoB. The data support the view of a direct synthesis and secretion of LDL, most probably by the fetal membranes

Estimating the spatial distribution of artificial groundwater recharge using multiple tracers.

Science.gov (United States)

Moeck, Christian; Radny, Dirk; Auckenthaler, Adrian; Berg, Michael; Hollender, Juliane; Schirmer, Mario

2017-10-01

Stable isotopes of water, organic micropollutants and hydrochemistry data are powerful tools for identifying different water types in areas where knowledge of the spatial distribution of different groundwater is critical for water resource management. An important question is how the assessments change if only one or a subset of these tracers is used. In this study, we estimate spatial artificial infiltration along an infiltration system with stage-discharge relationships and classify different water types based on the mentioned hydrochemistry data for a drinking water production area in Switzerland. Managed aquifer recharge via surface water that feeds into the aquifer creates a hydraulic barrier between contaminated groundwater and drinking water wells. We systematically compare the information from the aforementioned tracers and illustrate differences in distribution and mixing ratios. Despite uncertainties in the mixing ratios, we found that the overall spatial distribution of artificial infiltration is very similar for all the tracers. The highest infiltration occurred in the eastern part of the infiltration system, whereas infiltration in the western part was the lowest. More balanced infiltration within the infiltration system could cause the elevated groundwater mound to be distributed more evenly, preventing the natural inflow of contaminated groundwater. Dedicated to Professor Peter Fritz on the occasion of his 80th birthday.

Automatic monitoring of radial injection tracer tests using a novel multi-electrode resistivity system

International Nuclear Information System (INIS)

Ward, R.S.; Sen, M.A.; Williams, G.M.; Jackson, P.D.

1990-01-01

A radial injection tracer test has been carried out in an unconfined fluvial sand and gravel aquifer underlain by low permeability clay. Sodium chloride has been used as an electrolyte tracer and breakthrough has been monitored using a newly developed automatic resistivity system (RESCAN) incorporating six fully penetrating resistivity probes each having 80 electrodes spaced at 5 cm intervals along their length. Each electrode is individually addressable under computer control to either carry current or measure potential. Any four electrodes can be selected in the traditional Wenner configuration to measure formation resistivity. Rapid measurement of changes in resistivity allows a very detailed picture of tracer migration to be obtained. The resistivity probes were placed at 1 and 2 m radii from the central fully-screened tracer injection well along three limbs at 120 degrees. Resistivity measurements were compared with adjacent multi-level samplers. An 8 x 8 m grid of 140 surface electrodes centred on the central well was also installed. The resistivity profiles measured prior to tracer injection were used to infer lithology, particularly layering. Detailed breakthrough curves were obtained at 77 positions along each of the six probes and compared with adjacent multi-level sampler breakthrough curves. The results showed that the aquifer was extremely heterogeneous even on this small scale. Because the system operates automatically without the need to extract and analyse large numbers of water samples, it opens up the possibility of carrying out lots of small scale injection tests within a larger domain likely to be invaded by a tracer or pollution plume. Such detailed information for determining aquifer properties can provide the data set necessary for characterisation of the aquifer to predict dispersion parameters appropriate to the large scale. (Author) (6 refs., 9 figs., 2 tabs.)

Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain Site characterization study

International Nuclear Information System (INIS)

Dombrowski, T.; Stetzenbach, K.

1993-01-01

This report is in two parts one for the fluorinated benzoic acids and one for the fluorinated aliphatic acids. The assumptions made in the report regarding the amount of tracer that will be used, dilution of the tracer during the test and the length of exposure (if any) to individuals drinking the water were made by the authors. These assumptions must really come from the USGS hydrologists in charge of the c-well tracer testing program. Accurate estimates of dilution of the tracer during the test are also important because of solubility limitations of some of the tracers. Three of the difluorobenzoic acids have relatively low solubilities and may not be usable if the dilution estimates are large. The toxicologist that reviewed the document agreed with our conclusion that the fluorinated benzoic and toluic acids do not represent a health hazard if used under the conditions as outlined in the report. We are currently testing 15 of these compounds, and if even if three difluorobenzoic acids cannot be used because of solubility limitations we will still have 12 tracers. The toxicologist felt that the aliphatic fluorinated acids potentially present more of a health risk than the aromatic. This assessment was based on the fact of a known allergic response to halothane anesthetic. This risk, although minimal, is known and he felt that was enough reason to recommend against their use. The authors feel that the toxicologists interpretation of this risk was overly conservative, however, we will not go against his recommendation at this time for the following reasons. First, without the aliphatic compounds we still have 12 to 15 fluorinated aromatic acids which, should be enough for the c-well tests. Second, to get a permit to use aliphatic compounds would undoubtedly require a hearing which could be quite lengthy

3-D migration experiment - report 2: Instrumentation and tracers

International Nuclear Information System (INIS)

Abelin, H.; Birgersson, L.; Gidlund, J.

1987-11-01

This report is one of the four reports describing the Stripa 3D experiment where water and tracer flow has been monitored in a specially excavated drift in the Stripa mine. The experiment was performed in a specially excavated drift at the 360 m level in granite. The whole ceiling and upper part of the walls were covered with more than 350 individual plastic sheets where the water flow into the drift could be collected. 11 different tracers were injected at distances between 11 and 50 m from the ceiling of the drift. The flow rate and tracer monitoring was kept up for more than two years. The tracer breakthrough curves and flow rate distributions were used to study the flow paths, velocities, hydraulic conductivities, dispersivities and channeling effects in the rock. The report describes the instrumentation developed and used as well as the tracers that were tested and used in the experiment. (orig.)

Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging Data to Constrain a Positron Emission Tomography Kinetic Model: Theory and Simulations

Directory of Open Access Journals (Sweden)

Jacob U. Fluckiger

2013-01-01

Full Text Available We show how dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI data can constrain a compartmental model for analyzing dynamic positron emission tomography (PET data. We first develop the theory that enables the use of DCE-MRI data to separate whole tissue time activity curves (TACs available from dynamic PET data into individual TACs associated with the blood space, the extravascular-extracellular space (EES, and the extravascular-intracellular space (EIS. Then we simulate whole tissue TACs over a range of physiologically relevant kinetic parameter values and show that using appropriate DCE-MRI data can separate the PET TAC into the three components with accuracy that is noise dependent. The simulations show that accurate blood, EES, and EIS TACs can be obtained as evidenced by concordance correlation coefficients >0.9 between the true and estimated TACs. Additionally, provided that the estimated DCE-MRI parameters are within 10% of their true values, the errors in the PET kinetic parameters are within approximately 20% of their true values. The parameters returned by this approach may provide new information on the transport of a tracer in a variety of dynamic PET studies.

Radioisotope tracers in industrial flow studies

International Nuclear Information System (INIS)

Easey, J.F.

1987-01-01

The scope of radioisotope tracer work carried out by ANSTO has involved most sectors of Australian industry including iron and steel coal, chemical, petrochemical, natural gas, metallurgical, mineral, power generation, liquified air plant, as well as port authorities, water and sewerage instrumentalities, and environmental agencies. A major class of such studies concerns itself with flow and wear studies involving industrial equipment. Some examples are discussed which illustrate the utility of radioisotope tracer techniques in these applications

Tracers Detect Aquifer Contamination

National Research Council Canada - National Science Library

Enfield, Carl

1995-01-01

The EPA's National Laboratory (NRMRL) at Ada, OK, along with the University of Florida and the University of Texas, have developed a tracer procedure to detect the amount of contamination in aquifer formations...

Elements and inorganic ions as source tracers in recent Greenland snow

Science.gov (United States)

Lai, Alexandra M.; Shafer, Martin M.; Dibb, Jack E.; Polashenski, Chris M.; Schauer, James J.

2017-09-01

Atmospheric transport of aerosols leads to deposition of impurities in snow, even in areas of the Arctic as remote as Greenland. Major ions (e.g. Na+, Ca2+, NH4+, K+, SO42-) are frequently used as tracers for common aerosol sources (e.g. sea spray, dust, biomass burning, anthropogenic emissions). Trace element data can supplement tracer ion data by providing additional information about sources. Although many studies have considered either trace elements or major ions, few have reported both. This study determined total and water-soluble concentrations of 31 elements (Al, As, Ca, Cd, Ce, Co, Cr, Dy, Eu, Fe, Gd, K, La, Mg, Mn, Na, Nb, Nd, Pb, Pr, S, Sb, Si, Sm, Sn, Sr, Ti, V, U, Y, Zn) in shallow snow pits at 22 sampling sites in Greenland, along a transect from Summit Station to sites in the northwest. Black carbon (BC) and inorganic ions were measured in colocated samples. Sodium, which is typically used as a tracer of sea spray, did not appear to have any non-marine sources. The rare earth elements, alkaline earth elements (Mg, Ca, Sr), and other crustal elements (Fe, Si, Ti, V) were not enriched above crustal abundances relative to Al, indicating that these elements are primarily dust sourced. Calculated ratios of non-sea salt Ca (nssCa) to estimated dust mass affirm the use of nssCa as a dust tracer, but suggest up to 50% uncertainty in that estimate in the absence of other crustal element data. Crustal enrichment factors indicated that As, Cd, Pb, non-sea-salt S, Sb, Sn, and Zn were enriched in these samples, likely by anthropogenic sources. Principal component analysis indicated more than one crustal factor, and a variety of factors related to anthropogenically enriched elements. Analysis of trace elements alongside major tracer ions does not change interpretation of ion-based source attribution for sources that are well-characterized by ions, but is valuable for assessing uncertainty in source attribution and identifying sources not represented by major ions.

Feasibility of perfluorocarbon tracers (PFTs) in atmospheric source-receptor experiments

International Nuclear Information System (INIS)

Dietz, R.N.; Senum, G.I.

1984-03-01

A brief description of the perfluorocarbon tracer (PFT) system, which includes the tracers and the release equipment, the air samplers and the analyzers, is presented along with details on the research needs to provide a viable system for MATEX-scenario experiments. The present family of 2 viable PFTs needs to be increased to 5 to 6. Given the present precision of the analysis system, a one year long tracer experiment consisting of 4 hour releases every 60 hours from 5 different sites would require nearly 150 metric tons of PFTs at a cost of $15,000,000. Shortcomings in the programmable sampler include the pump, the sampling sequence control flexibility, data storage and retrieval, and the lack of remote communication capability; sampler adsorbent studies are also needed. The analytical system, including the catalyst processing bed, the chromatography column resolution, and the linearity of the detector, is in need of significant improvement. A higher resolution analysis system could significantly reduce analysis time but, more importantly, reduce tracer requirements more than 10-fold, for a cost savings potential of more than $13,000,000. A model is presented to demonstrate the feasibility of tracer material balances. Assessment of earlier long-range tracer experiments indicates the need for possibly 400 ground sampling sites requiring $8 to $14 million worth of samplers for a one-year tracer experiment. As many as six aircraft would be needed to conduct airborne model validation and material balance studies for each tracer plume

Root zone effects on tracer migration in arid zones

International Nuclear Information System (INIS)

Tyler, S.W.; Walker, G.R.

1994-01-01

The study of groundwater recharge and soil water movement in arid regions has received increased attention in the search for safe disposal sites for hazardous wastes. In passing through the upper 1 to 2 m of most soil profiles, tracers indicative of recharge such as Cl, 2 H, 18 O, Br, 3 H, and 56 Cl are subjected to a wide range of processes not encountered deeper in the profile. This transition zone, where water enters as precipitation and leaves as recharge, is often ignored when environmental tracers are used to estimate deep soil water flux and recharge, yet its effect may be profound. In this work, we reexamine the processes of root extraction and its effect on the velocity and distribution of tracers. Examples are presented for idealized conditions, which show clearly the relation between the root zone processes and the deep drainage or recharge. The results indicate that, when recharge is small and root zone processes are not accounted for, tracer techniques can significantly overestimate recharge until the tracer has moved well below the root zone. By incorporating simple models of root zone processes, a clearer understanding of tracer distributions and a more accurate estimate of recharge can then be made. 11 refs., 9 figs

KID - an algorithm for fast and efficient text mining used to automatically generate a database containing kinetic information of enzymes

Directory of Open Access Journals (Sweden)

Schomburg Dietmar

2010-07-01

Full Text Available Abstract Background The amount of available biological information is rapidly increasing and the focus of biological research has moved from single components to networks and even larger projects aiming at the analysis, modelling and simulation of biological networks as well as large scale comparison of cellular properties. It is therefore essential that biological knowledge is easily accessible. However, most information is contained in the written literature in an unstructured way, so that methods for the systematic extraction of knowledge directly from the primary literature have to be deployed. Description Here we present a text mining algorithm for the extraction of kinetic information such as KM, Ki, kcat etc. as well as associated information such as enzyme names, EC numbers, ligands, organisms, localisations, pH and temperatures. Using this rule- and dictionary-based approach, it was possible to extract 514,394 kinetic parameters of 13 categories (KM, Ki, kcat, kcat/KM, Vmax, IC50, S0.5, Kd, Ka, t1/2, pI, nH, specific activity, Vmax/KM from about 17 million PubMed abstracts and combine them with other data in the abstract. A manual verification of approx. 1,000 randomly chosen results yielded a recall between 51% and 84% and a precision ranging from 55% to 96%, depending of the category searched. The results were stored in a database and are available as "KID the KInetic Database" via the internet. Conclusions The presented algorithm delivers a considerable amount of information and therefore may aid to accelerate the research and the automated analysis required for today's systems biology approaches. The database obtained by analysing PubMed abstracts may be a valuable help in the field of chemical and biological kinetics. It is completely based upon text mining and therefore complements manually curated databases. The database is available at http://kid.tu-bs.de. The source code of the algorithm is provided under the GNU General Public

Use of (3H) and (125I) tracers in steroid radioimmunoassays

International Nuclear Information System (INIS)

Jeffcoate, S.L.

1975-01-01

The comparative use of 3 H and 125 I tracers in steroid radioimmunoassays will be discussed around the following points: - 3 H. Advantages: they can be purchased commercially and have a long shelf-life. Disadvantages: they may have reduced affinity for antibodies due to ''isotope effects''; the counting of β-emitters is more expensive and difficult; 3 H tracers are not available for all steroids. - 125 I. Advantages: gamma-counting is cheaper, simpler and more precise; 125 I tracers may have higher affinity for antibodies than unlabelled steroids; 125 I can be used to label any steroid. Disadvantages: 125 I tracers have a limited shelf-life (n.b. six months for 125 I histamine tracers). The high affinity of some tracers will be a big disadvantage if the unlabelled steroid cannot compete effectively

Systems approach to tracer data in groundwater hydrology

International Nuclear Information System (INIS)

Saxena, R.K.

1977-01-01

A brief review of current mathematical methods for the analysis of tracer data in groundwater hydrology has been given. The description of the hydrological cycle as a whole or in part, by a system (compartment) or sub-system under linear and stationary conditions is discussed. Basic concepts of transit time, residence time, their distributions in time and response characteristics of a system are outlined. From the knowledge of tracer input, output and systems response function for a generalised system, reservoir capacity and storage for given period can be estimated. Use of a time series model for environmental tracer data in discreet time scale aimed at the solution of hydrological problems e.g. mean transit time and reservoir capacity is also explored. It is concluded that the combination of tracer data with systems approach can go a long way in the study of some complex hydrological problems. (author)

Novel tracer for radiation treatment planning; Welche neuen PET-Tracer braucht die Strahlentherapie?

Energy Technology Data Exchange (ETDEWEB)

Schwarzenboeck, S.; Krause, B.J. [Rostock Univ. (Germany). Klinik fuer Nuklearmedizin; Herrmann, K.; Gaertner, F.; Souvatzoglou, M. [Technische Univ. Muenchen (Germany). Klinik fuer Nuklearmedizin; Klaesner, B. [Klinikum Bogenhausen, Muenchen (Germany). Inst. fuer Radiologie und Nuklearmedizin

2011-07-15

PET and PET/CT with innovative tracers gain increasing importance in diagnosis and therapy management, and radiation treatment planning in radio-oncology besides the widely established FDG. The introduction of [{sup 18}F]Fluorothymidine ([{sup 18}F]FLT) as marker of proliferation, [{sup 18}F]Fluoromisonidazole ([{sup 18}F]FMISO) and [{sup 18}F]Fluoroazomycin-Arabinoside ([{sup 18}F]FAZA) as tracer of hypoxia, [{sup 18}F]Fluoroethyltyrosine ([{sup 18}F]FET) and [{sup 11}C]Methionine for brain tumour imaging, [{sup 68}Ga]DOTATOC for somatostatin receptor imaging, [{sup 18}F]FDOPA for dopamine synthesis and radioactively labeled choline derivatives for imaging phospholipid metabolism have opened novel approaches to tumour imaging. Some of these tracers have already been implemented into radio-oncology: Amino acid PET and PET/CT have the potential to optimise radiation treatment planning of brain tumours through accurate delineation of tumour tissue from normal tissue, necrosis and edema. Hypoxia represents a major therapeutic problem in radiation therapy. Hypoxia imaging is very attractive as it may allow to increase the dose in hypoxic tumours potentially allowing for a better tumour control. Advances in hybrid imaging, i.e. the introduction of MR/PET, may also have an impact in radio-oncology through synergies related to the combination of molecular signals of PET and a high soft tissue contrast of MRI as well as functional MRI capabilities. (orig.)

Biodistribution of [11C] methylaminoisobutyric acid, a tracer for PET studies on system A amino acid transport in vivo

International Nuclear Information System (INIS)

Sutinen, E.; Jyrkkioe, S.; Groenroos, T.; Haaparanta, M.; Lehikoinen, P.; Naagren, K.

2001-01-01

[N-methyl- 11 C]α-Methylaminoisobutyric acid ( 11 C-MeAIB) is a potentially useful tracer for positron emission tomography (PET) studies on hormonally regulated system A amino acid transport. 11 C-MeAIB is a metabolically stable amino acid analogue specific for system A amino acid transport. We evaluated the biodistribution of 11 C-MeAIB in rats and humans to estimate the usefulness of the tracer for in vivo human PET studies, for example, on regulation of system A amino acid transport and on tumour imaging. Healthy Sprague-Dawley rats (n=14) were killed 5, 20, 40 or 60 min after the injection of 11 C-MeAIB, and the tissue samples were weighed and counted for 11 C radioactivity. Ten lymphoma patients with relatively limited tumour burden underwent whole-body (WB) PET imaging with 11 C-MeAIB. In addition, three other patients had dynamic PET scanning of the head and neck area, and the tracer uptake was quantitated by calculating the kinetic influx constants (K i values) for the tracer. In animal studies, the highest activity was detected in the kidney, pancreas, adrenal gland and intestines. In humans, the highest activity was found in the salivary glands, and after that in the kidney and pancreas, similar to the results in animal studies. Rapid uptake was also detected in the skeletal muscle. In the graphical analysis, linear plots were obtained, and the mean fractional tracer uptake values (K i ) of the parotid glands (n=3) and cervical muscles (n=3) were 0.039±0.008 min -1 and 0.013±0.006 min -1 , respectively. The K i value of the tumour (n=1) was 0.064 min -1 . Higher uptake of 11 C-MeAIB into the tumour tissue was encountered. These results encourage further 11 C-MeAIB PET studies in humans on the physiology and pathology of system A amino acid transport and on tumour detection. (orig.)

Crystallization Kinetics within a Generic Modelling Framework

DEFF Research Database (Denmark)

Meisler, Kresten Troelstrup; von Solms, Nicolas; Gernaey, Krist

2013-01-01

An existing generic modelling framework has been expanded with tools for kinetic model analysis. The analysis of kinetics is carried out within the framework where kinetic constitutive models are collected, analysed and utilized for the simulation of crystallization operations. A modelling...... procedure is proposed to gain the information of crystallization operation kinetic model analysis and utilize this for faster evaluation of crystallization operations....

Performance Testing of Tracer Gas and Tracer Aerosol Detectors for use in Radionuclide NESHAP Compliance Testing

Energy Technology Data Exchange (ETDEWEB)

Fuehne, David Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lattin, Rebecca Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-06-28

The Rad-NESHAP program, part of the Air Quality Compliance team of LANL’s Compliance Programs group (EPC-CP), and the Radiation Instrumentation & Calibration team, part of the Radiation Protection Services group (RP-SVS), frequently partner on issues relating to characterizing air flow streams. This memo documents the most recent example of this partnership, involving performance testing of sulfur hexafluoride detectors for use in stack gas mixing tests. Additionally, members of the Rad-NESHAP program performed a functional trending test on a pair of optical particle counters, comparing results from a non-calibrated instrument to a calibrated instrument. Prior to commissioning a new stack sampling system, the ANSI Standard for stack sampling requires that the stack sample location must meet several criteria, including uniformity of tracer gas and aerosol mixing in the air stream. For these mix tests, tracer media (sulfur hexafluoride gas or liquid oil aerosol particles) are injected into the stack air stream and the resulting air concentrations are measured across the plane of the stack at the proposed sampling location. The coefficient of variation of these media concentrations must be under 20% when evaluated over the central 2/3 area of the stack or duct. The instruments which measure these air concentrations must be tested prior to the stack tests in order to ensure their linear response to varying air concentrations of either tracer gas or tracer aerosol. The instruments used in tracer gas and aerosol mix testing cannot be calibrated by the LANL Standards and Calibration Laboratory, so they would normally be sent off-site for factory calibration by the vendor. Operational requirements can prevent formal factory calibration of some instruments after they have been used in hazardous settings, e.g., within a radiological facility with potential airborne contamination. The performance tests described in this document are intended to demonstrate the reliable

Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain site characterization study. Final report

International Nuclear Information System (INIS)

Stetzenbach, K.; Farnham, I.

1996-01-01

Extensive tracer testing is expected to take place at the C-well complex in the Nevada Test Site as part of the Yucca Mountain Site Characterization Project. The C-well complex consists of one pumping well, C3, and two injection wells, C1 and C2 into which tracer will be introduced. The goal of this research was to provide USGS with numerous tracers to completed these tests. Several classes of fluorinated organic acids have been evaluated. These include numerous isomers of fluorinated benzoic acids, cinnamic acids, and salicylic acids. Also several derivatives of 2-hydroxy nicotinic acid (pyridone) have been tested. The stability of these compounds was determined using batch and column tests. Ames testing (mutagenicity/carcinogenicity) was conducted on the fluorinated benzoic acids and a literature review of toxicity of the fluorobenzoates and three perfluoro aliphatic acids was prepared. Solubilities were measured and method development work was performed to optimize the detection of these compounds. A Quality Assurance (QA) Program was developed under existing DOE and USGS guidelines. The program includes QA procedures and technical standard operating procedures. A tracer test, using sodium iodide, was performed at the C-well complex. HRC chemists performed analyses on site, to provide real time data for the USGS hydrologists and in the laboratories at UNLV. Over 2,500 analyses were performed. This report provides the results of the laboratory experiments and literature reviews used to evaluate the potential tracers and reports on the results of the iodide C-well tracer test

Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain site characterization study. Final report

Energy Technology Data Exchange (ETDEWEB)

Stetzenbach, K.; Farnham, I.

1996-06-01

Extensive tracer testing is expected to take place at the C-well complex in the Nevada Test Site as part of the Yucca Mountain Site Characterization Project. The C-well complex consists of one pumping well, C3, and two injection wells, C1 and C2 into which tracer will be introduced. The goal of this research was to provide USGS with numerous tracers to completed these tests. Several classes of fluorinated organic acids have been evaluated. These include numerous isomers of fluorinated benzoic acids, cinnamic acids, and salicylic acids. Also several derivatives of 2-hydroxy nicotinic acid (pyridone) have been tested. The stability of these compounds was determined using batch and column tests. Ames testing (mutagenicity/carcinogenicity) was conducted on the fluorinated benzoic acids and a literature review of toxicity of the fluorobenzoates and three perfluoro aliphatic acids was prepared. Solubilities were measured and method development work was performed to optimize the detection of these compounds. A Quality Assurance (QA) Program was developed under existing DOE and USGS guidelines. The program includes QA procedures and technical standard operating procedures. A tracer test, using sodium iodide, was performed at the C-well complex. HRC chemists performed analyses on site, to provide real time data for the USGS hydrologists and in the laboratories at UNLV. Over 2,500 analyses were performed. This report provides the results of the laboratory experiments and literature reviews used to evaluate the potential tracers and reports on the results of the iodide C-well tracer test.

Tritium and deuterium as water tracers in hydrologic systems. Completion report

International Nuclear Information System (INIS)

Stewart, G.L.; Stetson, J.R.

1975-05-01

A study was conducted to evaluate the suitability of deuterium and tritium as tracers to depict water and pollutant movement in porous media. This involved studying the interaction of these tracers with soil materials and evaluating this interaction in terms of retardation in tracer flow velocity, compared to bulk water flow. Previous work had suggested that tritium and deuterium interact with soils and are removed from tracer solution during flow. The data presented clearly show that a tracing front becomes diluted in tracer during infiltration into oven-dried soil. There appears to be very little difference between the degree of tritium and deuterium interaction. The source of interaction is demonstrated to be primarily hydroxyl associated with the clay minerals. These exchange sites are destroyed by heating soil to 70C which eliminates tracer loss during infiltration

Analysis of some laboratory tracer runs in natural fissures

International Nuclear Information System (INIS)

Moreno, L.; Neretnieks, I.

1984-01-01

Tracer tests in natural fissures performed in the laboratory are analysed by means of fitting two different models. In the experiments, sorbing and non-sorbing tracers were injected into a natural fissure running parallel to the axis of a drill core. The models take into account advection, diffusion into the rock matrix, sorption onto the rock surface and dispersion. For the last mechanism, one of the models considers hydrodynamic dispersion while the other model assumes channeling dispersion. The models take into account time delays in the inlet and outlet channels. The dispersion characteristics and water residence time were determined from the experiments with non-sorbing tracers. Surface and volume sorption coefficients and data on diffusion into the rock matrix were determined for the sorbing tracers. The results are compared with values independently determined in the laboratory. Good agreement was obtained using either model. When these models are used for prediction of tracer transport over larger distances, the results will depend on the model. The model with channeling dispersion will show a greater dispersion than the model with hydrodynamic dispersion. (author)

The fluorescent tracer experiment on Holiday Beach near Mugu Canyon, Southern California

Science.gov (United States)

Kinsman, Nicole; Xu, J. P.

2012-01-01

After revisiting sand tracer techniques originally developed in the 1960s, a range of fluorescent coating formulations were tested in the laboratory. Explicit steps are presented for the preparation of the formulation evaluated to have superior attributes, a thermoplastic pigment/dye in a colloidal mixture with a vinyl chloride/vinyl acetate copolymer. In September 2010, 0.59 cubic meters of fluorescent tracer material was injected into the littoral zone about 4 kilometers upcoast of Mugu submarine canyon in California. The movement of tracer was monitored in three dimensions over the course of 4 days using manual and automated techniques. Detailed observations of the tracer's behavior in the coastal zone indicate that this tracer successfully mimicked the native beach sand and similar methods could be used to validate models of tracer movement in this type of environment. Recommendations including how to time successful tracer studies and how to scale the field of view of automated camera systems are presented along with the advantages and disadvantages of the described tracer methodology.

Enhanced Oil Recovery: Aqueous Flow Tracer Measurement

Energy Technology Data Exchange (ETDEWEB)

Joseph Rovani; John Schabron

2009-02-01

A low detection limit analytical method was developed to measure a suite of benzoic acid and fluorinated benzoic acid compounds intended for use as tracers for enhanced oil recovery operations. Although the new high performance liquid chromatography separation successfully measured the tracers in an aqueous matrix at low part per billion levels, the low detection limits could not be achieved in oil field water due to interference problems with the hydrocarbon-saturated water using the system's UV detector. Commercial instrument vendors were contacted in an effort to determine if mass spectrometry could be used as an alternate detection technique. The results of their work demonstrate that low part per billion analysis of the tracer compounds in oil field water could be achieved using ultra performance liquid chromatography mass spectrometry.

Dynamics and mechanics of bed-load tracer particles

Directory of Open Access Journals (Sweden)

C. B. Phillips

2014-12-01

Full Text Available Understanding the mechanics of bed load at the flood scale is necessary to link hydrology to landscape evolution. Here we report on observations of the transport of coarse sediment tracer particles in a cobble-bedded alluvial river and a step-pool bedrock tributary, at the individual flood and multi-annual timescales. Tracer particle data for each survey are composed of measured displacement lengths for individual particles, and the number of tagged particles mobilized. For single floods we find that measured tracer particle displacement lengths are exponentially distributed; the number of mobile particles increases linearly with peak flood Shields stress, indicating partial bed load transport for all observed floods; and modal displacement distances scale linearly with excess shear velocity. These findings provide quantitative field support for a recently proposed modeling framework based on momentum conservation at the grain scale. Tracer displacement is weakly negatively correlated with particle size at the individual flood scale; however cumulative travel distance begins to show a stronger inverse relation to grain size when measured over many transport events. The observed spatial sorting of tracers approaches that of the river bed, and is consistent with size-selective deposition models and laboratory experiments. Tracer displacement data for the bedrock and alluvial channels collapse onto a single curve – despite more than an order of magnitude difference in channel slope – when variations of critical Shields stress and flow resistance between the two are accounted for. Results show how bed load dynamics may be predicted from a record of river stage, providing a direct link between climate and sediment transport.

Methods for conduct of atmospheric tracer studies at ANSTO

Energy Technology Data Exchange (ETDEWEB)

Clark, G H; Stone, D J.M.; Pascoe, J H [Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia). Environment Division

2000-07-01

A perfluorocarbon atmospheric tracer system has been developed to investigate atmospheric dispersion processes in the region surrounding the Lucas Heights Science and Technology Centre. This report discusses the tracer release, sampling and analysis methods.

Development of activable tracers for application in secondary recovering in petroleum reservoirs

International Nuclear Information System (INIS)

Martins, Polyana Fabricia Fernandes; Moreira, Rubens Martins . Servico de Meio Ambiente e Tecnicas Nucleares.

2007-01-01

Nuclear methods are instrumental in describing detailed flow patterns and other features of oil reservoirs that are unattainable to other methods. Tracer studies in oil fields are performed in a net of injection and producing wells. Thus, the use of only one tracer species would not discriminate the contributions of distinct injection wells to the output of a given production well. Hence, a multi-tracer experiment is required, and the use of activable tracers, capable of being measured by neutron activation analysis (NAA) is here proposed. As additional tracer choices lanthanum (La) and europium (Eu) were chosen from the rare earth series due to their large neutron cross sections and general availability. In order to decrease losses to the oil phase and the retardation of the tracer relatively to the aqueous phase, these elements were complexed with organic chelating ligands: the polyaminocarboxylic acids EDTA, DTPA and DOTA. Infrared spectrometry was used to check complexation. In order to check the partition of the tracer between the aqueous and organic phases, tests were carried stirring the two phases together and measuring the tracer concentrations in the aqueous phase; the partition coefficient (Kao) was then calculated for all the combinations of the two lanthanides and the three ligands. Tests in which the tracer was continuously pumped through reservoir rock samples were also carried out using tritiated water as a reference tracer and the complexed lanthanides. (author)

Quantifying solute transport processes: are chemically "conservative" tracers electrically conservative?

Science.gov (United States)

Singha, Kamini; Li, Li; Day-Lewis, Frederick D.; Regberg, Aaron B.

2012-01-01

The concept of a nonreactive or conservative tracer, commonly invoked in investigations of solute transport, requires additional study in the context of electrical geophysical monitoring. Tracers that are commonly considered conservative may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system. As a result, the measured electrical conductivity may reflect not only solute transport but also reactive processes. We have evaluated the impacts of ion exchange reactions, rate-limited mass transfer, and surface conduction on quantifying tracer mass, mean arrival time, and temporal variance in laboratory-scale column experiments. Numerical examples showed that (1) ion exchange can lead to resistivity-estimated tracer mass, velocity, and dispersivity that may be inaccurate; (2) mass transfer leads to an overestimate in the mobile tracer mass and an underestimate in velocity when using electrical methods; and (3) surface conductance does not notably affect estimated moments when high-concentration tracers are used, although this phenomenon may be important at low concentrations or in sediments with high and/or spatially variable cation-exchange capacity. In all cases, colocated groundwater concentration measurements are of high importance for interpreting geophysical data with respect to the controlling transport processes of interest.

Molecular dynamics investigation of tracer diffusion in a simple liquid

International Nuclear Information System (INIS)

Ould-Kaddour, F.; Barrat, J.L.

1991-05-01

Extensive Molecular-Dynamics (MD) simulations have been carried out for a model trace-solvent system made up of 100 solvent molecules and 8 tracer molecules interacting through truncated Lennard-Jones potentials. The influence of the size ratio between solute and solvent, of their mass ratio and of the solvent viscosity on the diffusivity of a small tracer were investigated. Positive deviations from a Stokes-Einstein behaviour are observed, in qualitative agreement with experimental observations. It was also observed that as tracer and solvent become increasingly dissimilar, their respective dynamics becomes decoupled. We suggest that such decouplings can be interpreted by writing their mobility of the tracer as the sum of two terms, the first one arising from a coupling between tracer dynamics and hydrodynamics modes of the solvent, and the second one describing jump motion in a locally nearly frozen environment. (author). 17 refs, 4 figs, 6 tabs

Geologic flow characterization using tracer techniques

International Nuclear Information System (INIS)

Klett, R.D.; Tyner, C.E.; Hertel, E.S. Jr.

1981-04-01

A new tracer flow-test system has been developed for in situ characterization of geologic formations. This report describes two sets of test equipment: one portable and one for testing in deep formations. Equations are derived for in situ detector calibration, raw data reduction, and flow logging. Data analysis techniques are presented for computing porosity and permeability in unconfined isotropic media, and porosity, permeability and fracture characteristics in media with confined or unconfined two-dimensional flow. The effects of tracer pulse spreading due to divergence, dispersion, and porous formations are also included

Device and method for traditional chinese medicine diagnosis using radioactive tracer method

Energy Technology Data Exchange (ETDEWEB)

Wu, Shanling; Shen, Miaohe

1997-05-29

Disclosed is a device and method for traditional chinese medicine diagnosis using radioactive-tracer method. At least two nuclear radiation probes are arranged apart along the channels to detect the changing with time and on space of the intensity of radioactivity of the nuclear radioactive tracer which has been injected into the body in the channel position. The detected signals are amplified by amplifiers, and the outputs of the amplifiers are applied to data processing means which monitor the whole detecting process in real time and analyse and process the detected information about the changing of the intensity of radioactivity with time and on space indicating the operating of vital energy and blood, and obtain state parameters about operating of vital energy and blood in the body which is then output through data output means. (author) figs.

A comparison of measurements and calculations for the Stripa tracer experiments

International Nuclear Information System (INIS)

Hodgkinson, D.P.; Copper, N.S.

1992-03-01

This paper presents a comparison of measurements and predictions for migration of tracers from boreholes to the validation drift and to other boreholes in the Site Characterisation and Validation (SCV) block. The comparison was carried out on behalf of the Stripa task force on fracture flow modelling. The paper summarises the radar/saline tracer experiments, the tracer migration experiment observations and reviews the fracture flow and tracer transport modelling approaches and predictions made by AEA Technology, Fracflow Consultants, Golder Associates and Lawrence Berkeley Laboratory. The predictions are compared with the observed breakthrough curves on the basis of the validation process and criteria defined by the task force. The results of all four modelling groups met the validation criteria, with the predictions of the tracer breakthrough concentrations and times being within an order of magnitude of the observations. Also the AEA and Golder approaches allow the spatial distribution of tracer breakthrough into the validation drift to be predicted and these predictions also showed reasonable accuracy. The successful completion of this project demonstrates the feasibility of discrete fracture flow and tracer transport modelling. (36 refs.) (au)

Methionine kinetics in adult men: effects of dietary betaine on L-[2H3-methyl-1-13C]methionine

International Nuclear Information System (INIS)

Storch, K.J.; Wagner, D.A.; Young, V.R.

1991-01-01

The effects of a daily 3-g supplement of betaine on kinetic aspects of L-[2H3-methyl-1-13C]methionine (MET) metabolism in healthy young adult men were explored. Four groups of four subjects each were given a control diet, based on an L-amino acid mixture supplying 29.5 and 21.9 mg.kg-1.d-1 of L-methionine and L-cystine for 4 d before the tracer study, conducted on day 5 during the fed state. Two groups received the control diet and two groups received the betaine supplement. Tracer was given intravenously (iv) or orally. The transmethylation rate of MET (TM), homocysteine remethylation (RM), and oxidation of methionine were estimated from plasma methionine labeling and 13C enrichment of expired air. RM tended to increase (P = 0.14) but the TM and methionine oxidation were significantly (P less than 0.05) higher after betaine supplementation when estimated with the oral tracer. No differences were detected with the intravenous tracer. Methionine concentration in plasma obtained from blood taken from subjects in the fed state was higher (P less than 0.01) with betaine supplementation. These results suggest that excess methyl-group intake may increase the dietary requirement for methionine

A dual tracer ratio method for comparative emission measurements in an experimental dairy housing

Science.gov (United States)

Mohn, Joachim; Zeyer, Kerstin; Keck, Margret; Keller, Markus; Zähner, Michael; Poteko, Jernej; Emmenegger, Lukas; Schrade, Sabine

2018-04-01

Agriculture, and in particular dairy farming, is an important source of ammonia (NH3) and non-carbon dioxide greenhouse gas (GHG) emissions. This calls for the development and quantification of effective mitigation strategies. Our study presents the implementation of a dual tracer ratio method in a novel experimental dairy housing with two identical, but spatially separated housing areas. Modular design and flexible floor elements allow the assessment of structural, process engineering and organisational abatement measures at practical scale. Thereby, the emission reduction potential of specific abatement measures can be quantified in relation to a reference system. Emissions in the naturally ventilated housing are determined by continuous dosing of two artificial tracers (sulphur hexafluoride SF6, trifluoromethylsulphur pentafluoride SF5CF3) and their real-time detection in the ppt range with an optimized GC-ECD method. The two tracers are dosed into different experimental sections, which enables the independent assessment of both housing areas. Mass flow emissions of NH3 and GHGs are quantified by areal dosing of tracer gases and multipoint sampling as well as real-time analysis of both tracer and target gases. Validation experiments demonstrate that the technique is suitable for both areal and point emission sources and achieves an uncertainty of less than 10% for the mass emissions of NH3, methane (CH4) and carbon dioxide (CO2), which is superior to other currently available methods. Comparative emission measurements in this experimental dairy housing will provide reliable, currently unavailable information on emissions for Swiss dairy farming and demonstrate the reduction potential of mitigation measures for NH3, GHGs and potentially other pollutants.

Nanoparticle tracers in calcium carbonate porous media

KAUST Repository

Li, Yan Vivian

2014-07-15

Tracers are perhaps the most direct way of diagnosing subsurface fluid flow pathways for ground water decontamination and for natural gas and oil production. Nanoparticle tracers could be particularly effective because they do not diffuse away from the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles are not retained in the porous media as the result of aggregation or sticking to mineral surfaces. By screening eight nanoparticles (3-100 nm in diameter) for retention when passed through calcium carbonate packed laboratory columns in artificial oil field brine solutions of variable ionic strength we show that the nanoparticles with the least retention are 3 nm in diameter, nearly uncharged, and decorated with highly hydrophilic polymeric ligands. The details of these column experiments and the tri-modal distribution of zeta potential of the calcite sand particles in the brine used in our tests suggests that parts of the calcite surface have positive zeta potential and the retention of negatively charged nanoparticles occurs at these sites. Only neutral nanoparticles are immune to at least some retention. © 2014 Springer Science+Business Media.

Field measurements of tracer gas transport by barometric pumping

International Nuclear Information System (INIS)

Lagus, P.L.; McKinnis, W.B.; Hearst, J.R.; Burkhard, N.R.; Smith, C.F.

1994-01-01

Vertical gas motions induced by barometric pressure variations can carry radioactive gases out of the rubblized region produced by an underground nuclear explosion, through overburden rock, into the atmosphere. To better quantify transit time and amount of transport, field experiments were conducted at two sites on Pahute Mesa, Kapelli and Tierra, where radioactive gases had been earlier detected in surface cracks. At each site, two tracer gases were injected into the rubblized chimney 300-400 m beneath the surface and their arrival was monitored by concentration measurements in gas samples extracted from shallow collection holes. The first ''active'' tracer was driven by a large quantity of injected air; the second ''passive'' tracer was introduced with minimal gas drive to observe the natural transport by barometric pumping. Kapelli was injected in the fall of 1990, followed by Tierra in the fall of 1991. Data was collected at both sites through the summer of 1993. At both sites, no surface arrival of tracer was observed during the active phase of the experiment despite the injection of several million cubic feet of air, suggesting that cavity pressurization is likely to induce horizontal transport along high permeability layers rather than vertical transport to the surface. In contrast, the vertical pressure gradients associated with barometric pumping brought both tracers to the surface in comparable concentrations within three months at Kapelli, whereas 15 months elapsed before surface arrival at Tierra. At Kapelli, a quasisteady pumping regime was established, with tracer concentrations in effluent gases 1000 times smaller than concentrations thought to exist in the chimney. Tracer concentrations observed at Tierra were typically an order of magnitude smaller. Comparisons with theoretical calculations suggest that the gases are traveling through ∼1 millimeter vertical fractures spaced 2 to 4 meters apart. 6 refs., 18 figs., 3 tabs

Low-cost, High Flexibility I-V Curve Tracer for Photovoltaic Modules

DEFF Research Database (Denmark)

Ibirriaga, Julen Joseba Maestro; Pena, Xabier Miquelez de Mendiluce; Opritescu, Adrian

2010-01-01

This work presents the design, construction and test of an in-door low cost, high flexibility I-V curve tracer for photovoltaic modules. The tracer is connected to a Xenon lamp based flashing solar simulator. The designed tracer is able to deal with the very fast changing irradiation conditions...

Application of tracer techniques in studies of sediment transport in Vietnam

International Nuclear Information System (INIS)

Hai, P.S.; Quang, N.H.; Xuan, N.M.; Chuong, P.N.; Hien, P.Z.

1997-01-01

As a consequence of intensive erosion processes typical of the humid tropical one, as well as of human activities destroying tropical forests, grasslands and protective mangrove swamps, etc, most navigable estuaries in Vietnam suffer seriously from sedimentation. In order to maintain the necessary depth for the 7.000 ton vessels entering and leaving ports, a large amount of money is spent annually on dredging operation. A lot of hydraulic and sedimentary surveys were carried out in the past by different groups of researchers. However, owing to the complexity of sediment processes in estuarine areas under the hydrometeorological conditions typical of the southwest Pacific, the use of just any modelling approach is not suitable. In many cases, the conclusions inferred from mathematical models have been the controversial matter. The tracer techniques, which have been employed in the country since 1991, have provided a very efficient tool to obtain a dynamic idea of sediment transport. Many investigations of bedload transport using Sc-46 labelled glass and Ir-192 glass as radioactive tracers were carried out from 1992 to 1996 at Haiphong harbour area. Bedload transport rates under effect of northeast monsoon and southeast monsoon at 5 zones located on both sides of the navigation channel were estimated. In bedload transport studies, apart from conventional methods for assessment of transport thickness, a new method using the ratio of photoelectric peak to Compton region of spectra acquired directly on the sea bed was put forward and applied. The influence of dredging materials at two dumping sites under different tidal phases on in fill rate in the access channel was assessed by radioactive tracers. The qualitative and quantitative information on sediment transport at some experimental sites given by tracers was used by modelling specialists who have undertaken hydraulic and sedimentary surveys in this region

Our experience of blood flow measurements using radioactive tracers

International Nuclear Information System (INIS)

Danet, Bernard.

1974-01-01

A critical study of blood flow measuring methods is proposed. After a review of the various diffusible and non-diffusible radioactive tracers and the corresponding detector systems, the principles which allow to measure blood flow from the data so obtained, are studied. There is a different principle of flow measurement for each type of tracer. The theory of flow measurement using non-diffusible tracers (human serum albumin labelled with 131 I or sup(99m)Tc, 113 In-labelled siderophiline) and its application to cardiac flow measurement are described first. Then the theory of flow measurement using diffusible tracers ( 133 Xe, 85 Kr) and its application to measurement of blood flow through tissues (muscles and kidney particularly) are described. A personal experience of this various flow measurements is reported. The results obtained, the difficulties encountered and the improvments proposed are developed [fr

Deconvolution analysis of sup(99m)Tc-methylene diphosphonate kinetics in metabolic bone disease

Energy Technology Data Exchange (ETDEWEB)

Knop, J.; Kroeger, E.; Stritzke, P.; Schneider, C.; Kruse, H.P.

1981-02-01

The kinetics of sup(99m)Tc-methylene diphosphonate (MDP) and /sup 47/Ca were studied in three patients with osteoporosis, three patients with hyperparathyroidism, and two patients with osteomalacia. The activities of sup(99m)Tc-MDP were recorded in the lumbar spine, paravertebral soft tissues, and in venous blood samples for 1 h after injection. The results were submitted to deconvolution analysis to determine regional bone accumulation rates. /sup 47/Ca kinetics were analysed by a linear two-compartment model quantitating short-term mineral exchange, exchangeable bone calcium, and calcium accretion. The sup(99m)Tc-MDP accumulation rates were small in osteoporosis, greater in hyperparathyroidism, and greatest in osteomalacia. No correlations were obtained between sup(99m)Tc-MDP bone accumulation rates and the results of /sup 47/Ca kinetics. However, there was a significant relationship between the level of serum alkaline phosphatase and bone accumulation rates (R = 0.71, P < 0.025). As a result deconvolution analysis of regional sup(99m)Tc-MDP kinetics in dynamic bone scans might be useful to quantitate osseous tracer accumulation in metabolic bone disease. The lack of correlation between the results of sup(99m)Tc-MDP kinetics and /sup 47/Ca kinetics might suggest a preferential binding of sup(99m)Tc-MDP to the organic matrix of the bone, as has been suggested by other authors on the basis of experimental and clinical investigations.

Potential use of carbon-11 labeled alpha-aminoisobutyric acid (AIB) as an in vivo tracer of amino acid uptake in differing metabolic states

International Nuclear Information System (INIS)

Conti, P.S.; Starnes, H.F.; Brennan, M.F.

1986-01-01

AIB has been used as a model amino acid for the evaluation of alanine-preferring amino acid transport. Hormonal factors and starvation alter the tissue distribution of amino acids, particularly in liver and muscle. With positron emission tomography and labeling of biochemical tracers with C-11, (t1/2=20.4 min), it is now possible to study amino acid kinetics in vivo using external imaging. In order to investigate the utility of C-11 AIB as an in vivo tracer of altered tissue metabolism, C-14 AIB was studied in groups of rats with either streptozotocin-induced diabetes, insulin-induced hypoglycemia or starvation. The data suggest an increased amino acid uptake in liver in starvation, an increased uptake in muscle in response to insulin and associated hypoglycemia and decreased transport in muscle in starvation, as seen by other investigators. These results suggest that C-11 AIB may be useful as an in vivo monitor of metabolic changes in body tissues

Slew-rate dependence of tracer magnetization response in magnetic particle imaging

Science.gov (United States)

Shah, Saqlain A.; Ferguson, R. M.; Krishnan, K. M.

2014-10-01

Magnetic Particle Imaging (MPI) is a new biomedical imaging technique that produces real-time, high-resolution tomographic images of superparamagnetic iron oxide nanoparticle tracers. Currently, 25 kHz and 20 mT/μ0 excitation fields are common in MPI, but lower field amplitudes may be necessary for patient safety in future designs. Here, we address fundamental questions about MPI tracer magnetization dynamics and predict tracer performance in future scanners that employ new combinations of excitation field amplitude (Ho) and frequency (ω). Using an optimized, monodisperse MPI tracer, we studied how several combinations of drive field frequencies and amplitudes affect the tracer's response, using Magnetic Particle Spectrometry and AC hysteresis, for drive field conditions at 15.5, 26, and 40.2 kHz, with field amplitudes ranging from 7 to 52 mT/μ0. For both fluid and immobilized nanoparticle samples, we determined that magnetic response was dominated by Néel reversal. Furthermore, we observed that the peak slew-rate (ωHo) determined the tracer magnetic response. Smaller amplitudes provided correspondingly smaller field of view, sometimes resulting in excitation of minor hysteresis loops. Changing the drive field conditions but keeping the peak slew-rate constant kept the tracer response almost the same. Higher peak slew-rates led to reduced maximum signal intensity and greater coercivity in the tracer response. Our experimental results were in reasonable agreement with Stoner-Wohlfarth model based theories.

Numerical Simulation of a Tracer Experiment at the Wolsong Nuclear Site

International Nuclear Information System (INIS)

Jeong, Hyojoon; Kim, Eunhan; Park, Misun; Jeong, Haesun; Hwang, Wontae; Han, Moonhee

2014-01-01

By comparing the concentration of a tracer measured under weather conditions that are disadvantageous to the dilution of radioactive materials released from the Wolsong Nuclear Power Plant, with the concentration of a tracer calculated using an air Dispersion model, it is possible to evaluate the characteristics of the air concentrations of radioactive materials estimated with an air Dispersion model, which can then be used in an environmental impact analysis of radioactive materials. Therefore, a field Dispersion experiment has been carried out to figure out the behavioral characteristics of the tracer under weather conditions that are disadvantageous to the dilution of radioactive materials released from the Wolsong Nuclear Power Plant site in Korea. In addition, through a comparison of the tracer concentrations estimated by the Gaussian plume model with measurements, this study checked the degree of conservative estimation for the Gaussian plume at the Wolsong nuclear site in Korea. A tracer Dispersion experiment using an SF 6 trace was implemented to determine the Dispersion characteristics of radioactive materials at the Wolsong Nuclear Power Plant site in Korea. Based on meteorological data and the emission rate of the tracers, this study estimated the tracer concentrations using a Gaussian plume model, and then compared it with the measurement to check the conservative estimation of the Gaussian plume model. The measured concentrations of the tracer tends to be lower than the concentrations estimated by the Gaussian plume model overall

The use of 123I-labeled heptadecanoic acid (HDA) as metabolitic tracer

International Nuclear Information System (INIS)

Dudczak, R.; Kletter, K.; Frischauf, H.; Schmoliner, R.; Losert, U.; Angelberger, P.

1984-01-01

The feasibility of using 123 I-heptadecanoic acid (HDA) as a metabolic tracer was studied. Different administration routes of HDA were compared. An intracoronary bolus injection was given to calves (n=3), and an intravenous injection was given to patients (n=4). In addition, we examined the influence of 4-h halothane anesthesia in calves and in patients the impact of an isulin (1.5 IU/kg)+glucose (1.5 g/kg) infusion on the myocardial kinetics of HDA. Data were accumulated with a scintillation probe in calves (t=50 min) and a gamma camera in patients (t=70 min). In calves after an intracoronary bolus injection of HDA the myocardial time-activity curve could be described by two exponentials. The mean elimination half-time of the initial phase (tsub(a) 1/2) was 7.3 min and that of the second phase (tsub(b) 1/2) was 35 min. The ratio of the size of the initial and second component at t 0 was 0.93. Halothane anesthesia prolonged the elimination half-times and reduced the component ratio. The biphasic behavior of the myocardial time-activity curve was maintained in patients after intravenous administration of HDA under basal conditions (inital tsub(a) 1/2=8.4 min). However, during infusion of insulin+glucose the decline in the myocardial activity was prolonged and monoexponential. This data show that insulin glucose, interfering with fatty acid metabolism, influences the myocardial washout of HDA, and thus support it use as a metabolic tracer. (orig.)

Estimation of the dilution field near a marine outfall by using effluent turbidity as an environmental tracer and comparison with dye tracer data.

Science.gov (United States)

Pecly, José Otavio Goulart

2018-01-01

The alternative use of effluent turbidity to determine the dilution field of a domestic marine outfall located off the city of Rio de Janeiro was evaluated through field work comprising fluorescent dye tracer injection and tracking with simultaneous monitoring of sea water turbidity. A preliminary laboratory assessment was carried out with a sample of the outfall effluent whose turbidity was measured by the nephelometric method before and during a serial dilution process. During the field campaign, the dye tracer was monitored with field fluorometers and the turbidity was observed with an optical backscattering sensor interfaced to an OEM data acquisition system. About 4,000 samples were gathered, covering an area of 3 km × 3 km near the outfall diffusers. At the far field - where a drift towards the coastline was observed - the effluent plume was adequately labeled by the dye tracer. The turbidity plume was biased due to the high and variable background turbidity of sea water. After processing the turbidity dataset with a baseline detrending method, the plume presented high correlation with the dye tracer plume drawn on the near dilution field. However, dye tracer remains more robust than effluent turbidity.

Comparative study on ion-isotopic exchange reaction kinetics by application of tracer technique

International Nuclear Information System (INIS)

Lokhande, R.S.; Singare, P.U.

2007-01-01

The radioactive isotopes 131 I and 82 Br were used to trace the ion-isotopic exchange reactions using industrial grade ion exchange resins Amberlite IRA-400. The experiments were performed to understand the effect of temperature and concentration of ionic solution on kinetics of exchange reactions. Both the exchange reactions were greatly influenced by rise in temperature, which result in higher percentage of ions exchanged. For bromide ion-isotopic exchange reactions, the calculated values of specific reaction rate/min -1 , and amount of ions exchanged/mmol were obtained higher than that for iodide ion-isotopic exchange reactions under identical experimental conditions. The observed variation in the results for two ion-isotopic exchange reactions was due to the difference in the ionic size of bromide and iodide ions. (orig.)

Tracer gas diffusion sampling test plan

International Nuclear Information System (INIS)

Rohay, V.J.

1993-01-01

Efforts are under way to employ active and passive vapor extraction to remove carbon tetrachloride from the soil in the 200 West Area an the Hanford Site as part of the 200 West Area Carbon Tetrachloride Expedited Response Action. In the active approach, a vacuum is applied to a well, which causes soil gas surrounding the well to be drawn up to the surface. The contaminated air is cleaned by passage through a granular activated carbon bed. There are questions concerning the radius of influence associated with application of the vacuum system and related uncertainties about the soil-gas diffusion rates with and without the vacuum system present. To address these questions, a series of tracer gas diffusion sampling tests is proposed in which an inert, nontoxic tracer gas, sulfur hexafluoride (SF 6 ), will be injected into a well, and the rates of SF 6 diffusion through the surrounding soil horizon will be measured by sampling in nearby wells. Tracer gas tests will be conducted at sites very near the active vacuum extraction system and also at sites beyond the radius of influence of the active vacuum system. In the passive vapor extraction approach, barometric pressure fluctuations cause soil gas to be drawn to the surface through the well. At the passive sites, the effects of barometric ''pumping'' due to changes in atmospheric pressure will be investigated. Application of tracer gas testing to both the active and passive vapor extraction methods is described in the wellfield enhancement work plan (Rohay and Cameron 1993)

Partitioning tracers for measuring residual NAPL: Field-scale test results

International Nuclear Information System (INIS)

Annable, M.D.; Rao, P.S.C.; Hatfield, K.; Graham, W.D.; Wood, A.L.; Enfield, C.G.

1998-01-01

The difficult task of locating and quantifying nonaqueous phase liquids (NAPLs) present in the vadose and saturated zones has prompted the development of innovative, nondestructive characterization techniques. The use of the interwell partitioning tracer's (IWPT) test, in which tracers that partition into the NAPL phase are displaced through the aquifer, is an attractive alternative to traditional coring and analysis. The first field test of IWPT was conducted in a hydraulically isolated test cell to quantify the total amount of a complex NAPL (a mixture of JP-4 jet fuel and chlorinated solvents) trapped within a 1.5-m smear zone in a shallow, unconfined sand and gravel aquifer at Hill Air Force Base (AFB), Utah. Tracer breakthrough curves (BTCs) were measured in three extraction wells (EWs) following a tracer pulse introduction through four injection wells (IWs). The measured retardation of the partitioning tracer (2,2-dimethyl-3-pentanol) relative to the nonreactive tracer (bromide) was used to quantify the NAPL present. The EW data were used to estimate an average NAPL saturation of 4.6--5.4% within the test cell. NAPL saturations estimated by using measured concentrations in soil cores of two significant compounds present in the NAPL were 3.0 and 4.6%

Models for tracer flow

International Nuclear Information System (INIS)

Zuber, A.

1983-01-01

A review and discussion is given of mathematical models used for interpretation of tracer experiments in hydrology. For dispersion model, different initial and boundary conditions are related to different injection and detection modes. Examples of applications of various models are described and commented. (author)

Tracer transport modeling with the Alliances platform in the presence of evapotranspiration

Energy Technology Data Exchange (ETDEWEB)

Constantin, A.; Diaconu, D.; Bucur, C. [Institute for Nuclear Research, Pitesti (Romania); Genty, A. [CEA Saclay, Gif-sur-Yvette (France)

2013-11-15

The knowledge and understanding of water flow and solute transport in the unsaturated zone is becoming increasingly important especially in mitigation of groundwater pollution. Fate of radionuclide in the geological environment is a topic to address in performance and safety assessment studies for nuclear waste disposal and may be modeled considering flow and transport in porous media. However, often, due to the heterogeneity and anisotropy of the real systems, the computer simulations may be difficult to render the real behavior. This paper addresses the simulation of a tracer transport in the unsaturated zone of the Saligny site, the potential location for the Romanian low and intermediate level waste (LILW) disposal. Computation was based on experimental data and was performed with the Alliances platform, a numerical tool developed by French organizations CEA, ANDRA and EDF. In order to obtain information regarding the solute migration in depth and the solute lateral dispersion, the dispersivity coefficients of iodine were investigated in order to match the experimental concentration determined on samples from different locations of the site. A close fit of the simulation over experimental data for the water saturation profile at a depth of 0.5 m in transient state was targeted by taking into account evapotranspiration in order to obtain a realistic estimation of the water infiltration in the porous media. Dispersivity coefficients obtained from the simulation of the tracer transport are in good order of magnitude for the unsaturated area and allow to have a good preview of the tracer plume. However, further investigations are recommended on new samples in order to validate the migration of the tracer plume as expected. (orig.)

Kinetics of Reactive Fronts in Porous Media: quantification through a laboratory experiment

Science.gov (United States)

De Anna, P.; Jimenez-Martinez, J.; Turuban, R.; Tabuteau, H.; Derrien, M.; Le Borgne, T.; Meheust, Y.

2013-12-01

The kinetics of reaction fronts in heterogeneous flows is tightly linked to the mixing dynamics governed by the combined action of stretching, diffusion and dispersion. Focusing on porous media flows, with a new experimental setup we show that the invading solute is organized into stretched lamellae, whose deformation and coalescence control the effective reaction kinetics of the mixing limited bimolecular reaction A + B --> C. While the classic advection-dispersion theory predicts a scaling of the cumulative product mass of C as t^(0.5), we observe two distinct kinetics regimes, one characterized by the stretching and the other by the coalescence of the invading lamellae, in which the mass of C scales faster than t^(0.5). The proposed experimental set up allows for direct quantification of mixing and reactive transport in porous media with a high spatial resolution, at the pore scale. The analogous two dimensional porous medium consists in a Hele-Shaw cell containing a single layer of cylindrical solid grains built by soft lithography. On the one hand, the measurement of the local, intra-pore, conservative concentration field is done using a fluorescent tracer. On the other hand, considering a fast bimolecular advection-dispersion reaction A + B --> C occurring as A displaces B, we quantify the reaction kinetics from the spatially-resolved measurement of the pore scale reaction rate, using a chemiluminescent reaction.

Key aspects of stratospheric tracer modeling using assimilated winds

Directory of Open Access Journals (Sweden)

B. Bregman

2006-01-01

Full Text Available This study describes key aspects of global chemistry-transport models and their impact on stratospheric tracer transport. We concentrate on global models that use assimilated winds from numerical weather predictions, but the results also apply to tracer transport in general circulation models. We examined grid resolution, numerical diffusion, air parcel dispersion, the wind or mass flux update frequency, and time interpolation. The evaluation is performed with assimilated meteorology from the "operational analyses or operational data" (OD from the European Centre for Medium-Range Weather Forecasts (ECMWF. We also show the effect of the mass flux update frequency using the ECMWF 40-year re-analyses (ERA40. We applied the three-dimensional chemistry-transport Tracer Model version 5 (TM5 and a trajectory model and performed several diagnoses focusing on different transport regimes. Covering different time and spatial scales, we examined (1 polar vortex dynamics during the Arctic winter, (2 the large-scale stratospheric meridional circulation, and (3 air parcel dispersion in the tropical lower stratosphere. Tracer distributions inside the Arctic polar vortex show considerably worse agreement with observations when the model grid resolution in the polar region is reduced to avoid numerical instability. The results are sensitive to the diffusivity of the advection. Nevertheless, the use of a computational cheaper but diffusive advection scheme is feasible for tracer transport when the horizontal grid resolution is equal or smaller than 1 degree. The use of time interpolated winds improves the tracer distributions, particularly in the middle and upper stratosphere. Considerable improvement is found both in the large-scale tracer distribution and in the polar regions when the update frequency of the assimilated winds is increased from 6 to 3 h. It considerably reduces the vertical dispersion of air parcels in the tropical lower stratosphere. Strong

Kinetic compartmental analysis of carnitine metabolism in the human carnitine deficiency syndromes. Evidence for alterations in tissue carnitine transport.

OpenAIRE

Rebouche, C J; Engel, A G

1984-01-01

The human primary carnitine deficiency syndromes are potentially fatal disorders affecting children and adults. The molecular etiologies of these syndromes have not been determined. In this investigation, we considered the hypothesis that these syndromes result from defective transport of carnitine into tissues, particularly skeletal muscle. The problem was approached by mathematical modeling, by using the technique of kinetic compartmental analysis. A tracer dose of L-[methyl-3H]carnitine wa...

Tracer techniques in food industry

International Nuclear Information System (INIS)

Pertsovskij, E.S.; Sakharov, Eh.V.; Dolinin, V.A.

1980-01-01

The appicability of radioactive tracer techniques to process control in food industry are considered. Investigations in the field of food industry carried out using the above method are classified. The 1 class included investigations with preliminary preparation of a radioactive indicator and its following introduction in the system studied. The 2 class includes investigations based on the introduction in the system studied of a non-active indicator which is activated in a neutron flux being in samples selected in or after the process investigated. The 3 class includes studies based on investigations of natural radioactivity of certain nuclides in food stuff. The application of tracer techniques to the above classes of investigations in various fields of food industry and the equipment applied are considered in detail [ru

Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers

KAUST Repository

Subramanian, S. K.; Li, Yan; Cathles, L. M.

2013-01-01

The exact manner in which preferential (e.g., much faster than average) flow occurs in the subsurface through small fractures or permeable connected pathways of other kinds is important to many processes but is difficult to determine, because most chemical tracers diffuse quickly enough from small flow channels that they appear to move more uniformly through the rock than they actually do. We show how preferential flow can be assessed by injecting 2 to 5 nm carbon particles (C-Dots) and an inert KBr chemical tracer at different flow rates into a permeable core channel that is surrounded by a less permeable matrix in laboratory apparatus of three different designs. When the KBr tracer has a long enough transit through the system to diffuse into the matrix, but the C-Dot tracer does not, the C-Dot tracer arrives first and the KBr tracer later, and the separation measures the degree of preferential flow. Tracer sequestration in the matrix can be estimated with a Peclet number, and this is useful for experiment design. A model is used to determine the best fitting core and matrix dispersion parameters and refine estimates of the core and matrix porosities. Almost the same parameter values explain all experiments. The methods demonstrated in the laboratory can be applied to field tests. If nanoparticles can be designed that do not stick while flowing through the subsurface, the methods presented here could be used to determine the degree of fracture control in natural environments, and this capability would have very wide ranging value and applicability.

Ab-initio modelling of thermodynamics and kinetics of point defects in indium oxide

International Nuclear Information System (INIS)

Agoston, Peter; Klein, Andreas; Albe, Karsten; Erhart, Paul

2008-01-01

The electrical and optical properties of indium oxide films strongly vary with the processing parameters. Especially the oxygen partial pressure and temperature determine properties like electrical conductivity, composition and transparency. Since this material owes its remarkable properties like the intrinsic n-type conductivity to its defect chemistry, it is important to understand both, the equilibrium defect thermodynamics and kinetics of the intrinsic point defects. In this contribution we present a defect model based on DFT total energy calculations using the GGA+U method. Further, the nudged elastic band method is employed in order to obtain a set of migration barriers for each defect species. Due to the complicated crystal structure of indium oxide a Kinetic Monte-Carlo algorithm was implemented, which allows to determine diffusion coefficients. The bulk tracer diffusion constant is predicted as a function of oxygen partial pressure, Fermi level and temperature for the pure material

Application of tracer isotope in kinetic study of first order ion exchange reaction

International Nuclear Information System (INIS)

Lokhande, R.S.; Singare, P.U.

1998-01-01

Analysis of first order ion exchange reaction rates at different temperatures (27 deg- 48 degC) and particularly at low concentration of potassium iodide solution (electrolyte) ranging from 0.005 M to 0.040 M is carried out by application of radioactive tracer isotope 131 I. With increase in concentration of electrolyte, amount of iodide ion exchanged in millimoles increases. Specific reaction rates of ion exchange reaction are calculated for different temperatures and for different amount of ion exchange resins. It is observed that with increase in temperature, reaction rate increases but the increase is more pronounced for increase in amount of ion exchange resins. For 0.005 M solution of electrolyte, the reaction rate increases from 0.121 min -1 at 27 degC to 0.178 min -1 at 48 degC. For 0.005 M solution of electrolyte the reaction rate increases from 0.121 min -1 at 27 degC to 0.178 min 1 at 48 degC. For 0.005 M solution of electrolyte at 27 degC the reaction rate increases from 0.121 min -1 for 1.0 g of resin to 0.368 min -1 for 5.0 g of resin. From the reaction rates calculated at different temperatures, energy of activation in kJ/mole is calculated. It is observed that for 0.005 M solution of electrolyte, energy of activation is 4.62 kJ/mole which decreases to 2.87 kJ/mole for increase in concentration of electrolyte to 0.100 M. (author)

Kinetic parameters from thermogravimetric analysis

Science.gov (United States)

Kiefer, Richard L.

1993-01-01

High performance polymeric materials are finding increased use in aerospace applications. Proposed high speed aircraft will require materials to withstand high temperatures in an oxidative atmosphere for long periods of time. It is essential that accurate estimates be made of the performance of these materials at the given conditions of temperature and time. Temperatures of 350 F (177 C) and times of 60,000 to 100,000 hours are anticipated. In order to survey a large number of high performance polymeric materials on a reasonable time scale, some form of accelerated testing must be performed. A knowledge of the rate of a process can be used to predict the lifetime of that process. Thermogravimetric analysis (TGA) has frequently been used to determine kinetic information for degradation reactions in polymeric materials. Flynn and Wall studied a number of methods for using TGA experiments to determine kinetic information in polymer reactions. Kinetic parameters, such as the apparent activation energy and the frequency factor, can be determined in such experiments. Recently, researchers at the McDonnell Douglas Research Laboratory suggested that a graph of the logarithm of the frequency factor against the apparent activation energy can be used to predict long-term thermo-oxidative stability for polymeric materials. Such a graph has been called a kinetic map. In this study, thermogravimetric analyses were performed in air to study the thermo-oxidative degradation of several high performance polymers and to plot their kinetic parameters on a kinetic map.

Chemical and Isotopic Tracers of Groundwater Sustainability: an Overview of New Science Directions

Science.gov (United States)

Bullen, T.

2002-12-01

Groundwater sustainability is an emerging concept that is rapidly gaining attention from both scientists and water resource managers, particularly with regard to contamination and degradation of water quality in strategic aquifers. The sustainability of a groundwater resource is a complex function of its susceptibility to factors such as intrusion of poor-quality water from diverse sources, lack of sufficient recharge and reorganization of groundwater flowpaths in response to excessive abstraction. In theory the critical limit occurs when degradation becomes irreversible, such that remediative efforts may be fruitless on a reasonable human time scale. Chemical and isotopic tracers are proving to be especially useful tools for assessment of groundwater sustainability issues such as characterization of recharge, identification of potential sources, pathways and impacts of contaminants and prediction of how hydrology will change in response to excessive abstraction. A variety of relatively cost-efficient tracers are now available with which to assess the susceptibility of groundwater reserves to contamination from both natural and anthropogenic sources, and may provide valuable monitoring and regulatory tools for water resource managers. In this overview, the results of several ongoing groundwater studies by the U.S. Geological Survey will be discussed from the perspective of implications for new science directions for groundwater sustainability research that can benefit water policy development. A fundamental concept is that chemical and isotopic tracers used individually often provide ambiguous information, and are most effective when used in a rigorous "multi-tracer" context that considers the complex linkages between the hydrology, geology and biology of groundwater systems.

Using environmental tracer data to identify deep-aquifer, long-term flow patterns and recharge distributions in the Surat Basin, Queensland, Australia

Science.gov (United States)

Siade, A. J.; Suckow, A. O.; Morris, R.; Raiber, M.; Prommer, H.

2017-12-01

The calibration of regional groundwater flow models, including those investigating coal-seam gas (CSG) impacts in the Surat Basin, Australia, are not typically constrained using environmental tracers, although the use of such data can potentially provide significant reductions in predictive uncertainties. These additional sources of information can also improve the conceptualisation of flow systems and the quantification of groundwater fluxes. In this study, new multi-tracer data (14C, 39Ar, 81Kr, and 36Cl) were collected for the eastern recharge areas of the basin and within the deeper Hutton and Precipice Sandstone formations to complement existing environmental tracer data. These data were used to better understand the recharge mechanisms, recharge rates and the hydraulic properties associated with deep aquifer systems in the Surat Basin. Together with newly acquired pressure data documenting the response to the large-scale reinjection of highly treated CSG co-produced water, the environmental tracer data helped to improve the conceptualisation of the aquifer system, forming the basis for a more robust quantification of the long-term impacts of CSG-related activities. An existing regional scale MODFLOW-USG groundwater flow model of the area was used as the basis for our analysis of existing and new observation data. A variety of surrogate modelling approaches were used to develop simplified models that focussed on the flow and transport behaviour of the deep aquifer systems. These surrogate models were able to represent sub-system behaviour in terms of flow, multi-environmental tracer transport and the observed large-scale hydrogeochemical patterns. The incorporation of the environmental tracer data into the modelling framework provide an improved understanding of the flow regimes of the deeper aquifer systems as well as valuable information on how to reduce uncertainties in hydraulic properties where there is little or no historical observations of hydraulic

Diffusing passive tracers in random incompressible flows: Statistical topography aspects

International Nuclear Information System (INIS)

Klyatskin, V.I.; Woyczynski, W.A.; Gurarie, D.

1996-01-01

The paper studies statistical characteristics of the passive tracer concentrations and of its spatial gradient, in random incompressible velocity fields from the viewpoint of statistical topography. The statistics of interest include mean values, probability distributions, as well as various functionals characterizing topographic features of tracers. The functional approach is used. We consider the influence of the mean flow (the linear shear flow) and the molecular diffusion coefficient on the statistics of the tracer. Most of our analysis is carried out in the framework of the delta-correlated (in time) approximation and conditions for its applicability are established. But we also consider the diffusion approximation scheme for finite correlation radius. The latter is applied to a diffusing passive tracer that undergoes sedimentation in a random velocity field

USING PERFLUOROCARBON TRACERS FOR VERIFICATION OF CAP AND COVER SYSTEMS PERFORMANCE

International Nuclear Information System (INIS)

HEISER, J.; SULLIVAN, T.

2001-01-01

subsurface barriers (1,2). The technology uses perfluorocarbon tracers (PFTs) to determine flaws (e.g., holes or cracks) and high permeability areas in subsurface barriers. Gaseous tracers are injected on one side of the barrier and searched for on the opposite side of the barrier. The sampling grid, concentration, and time of arrival of the tracer(s) on the opposite side are used to determine the size and location of flaws and relative permeability of the barrier. In addition, there are multiple tracers available, which allows different tracers to be injected in different quadrants of the barrier. This yields additional information on transport phenomena of the barrier

Development of radioisotope tracer technology and nucleonic control system

Energy Technology Data Exchange (ETDEWEB)

Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee and others

1999-04-01

The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and basic technology of nuclear control systems that are widely used for automation of industrial plants, and to build a strong tracer group to support the local industries. In relation to the tracer technology, the data acquisition system, the column scanning equipment and the detection pig for a leakage test have been developed. In order to use in analyzing data of tracer experiments, a computer program for the analysis of residence time distribution has been created as well. These results were utilized in developing the tracer technologies, such as the column scanning, the flow measurement using the dilution method, the simultaneous monitoring rotational movement of piston rings and the optimization of a waste water treatment facility, and the technologies were successfully demonstrated in the local industrial. The stripper of RFCC reactor has been examined to find an unwanted structure in it by imminent request from the industry. Related to the development of nucleonic control system, the state of art report on the technology has been written and an equipment for the analysis of asphalt content has been developed. (author)

Analysis of the kinetics of ovine follitropin agonist-antagonist interactions with pig ovarian membranes

Energy Technology Data Exchange (ETDEWEB)

Sebok, K.; De Lean, A.; Sairam, M.R.

1987-06-16

The binding of /sup 125/I-labeled ovine follitropin (oFSH) and /sup 125/I-labeled deglycosylated ovine follitropin (DG-oFSH) to porcine granulosa cell membranes was studied at equilibrium and nonequilibrium binding conditions and statically analyzed. Saturation and competition binding experiments revealed homogeneity in the population of binding sites labeled with /sup 125/I-oFSH, having a pK estimation of approx.10. /sup 125/I-DG-oFSH similarly interacts with a single uniform class of receptors of equal affinity (pK approx. 10) and binding capacity as oFSH. In contrast, displacement experiments using /sup 125/I-DG-oFSH as tracer and unlabeled oFSH as competing ligand demonstrate slope factors less than unity, suggesting apparent heterogeneity of sites not observed with /sup 125/I-DG-oFSH vs. DG-oFSH competition experiments. Under these conditions, it appears that FSH binds to two sites in near equal proportion but of unequal affinities. The total specific binding capacities of these sites equal those observed in /sup 125/I-DG-oFSH/unlabeled DG-oFSH competition experiments. Analysis of oFSH association kinetics at 37 /sup 0/C by curve-fitting methods is best explained by a biexponential rate equation describing a fast and a slow association component that are equally distributed. DG-oFSH demonstrates a disproportionately greater amount of fast vs. slow binding component. Dissociation, promoted by the same unlabeled hormone, of bound /sup 125/I-DG-oFSH and /sup 125/I-oFSH induces biphasic kinetics consisting of a fast and a slow dissociable pool of prebound tracer. Computer analysis reveals that both tracers dissociate with similar fast t/sub 1/2/ times; however, DG-oFSH exhibited a t/sub 1/2/ approximately 2 times slower for the component vs. oFSH. From this study, it is concluded that oFSH and DG-oFSH bind to the receptor(s) in a complex reaction scheme, more so for oFSH than DG-oFSH.

Interpretation of Water Tracer Simulation in the H-1 Segment of the Gullfaks Field

Energy Technology Data Exchange (ETDEWEB)

Moid, Farrukh

2000-07-01

This thesis describes the water tracer simulation in the H-1 segment of the Gullfaks field. Three passive water tracer slugs were injected from the two producing wells during water flooding, pressure maintenance and reservoir monitoring program in the Gullfaks field. The same program is considered in this thesis. Computer Modelling Group's (CMG) simulator STARS is used for the general reservoir simulation and a separate module for tracer flow (ITRC-SIM) which is incorporated in the STARS and developed at Institute For Energy (IFE) is used for the tracer simulation. Water cut and tracer concentration data are used in history matching of the field. History matching is performed by changing the transmissibility and permeability of different layers; also the effect of changing saturations near the well bore on history matching is examined. It is noted that water cut is sensitive to transmissibility of the layers and the saturation around the well bore. Tracers are found to be moving in the most permeable layers. The corresponding history matching of water and tracer production shows a severe loss of first tracer injected because of imbibition process. Water phase velocity and areal communication between different wells are determined. Advance numerical features of tracer module ITRC-SIM such as flux limiting scheme and grid refinement scheme are evaluated and are found to be an important tool for reducing the numerical smearing. The effects of dispersion and diffusion on tracer response curve are also evaluated. Dispersion makes the tracer concentration curve smeared. Simulation results of water cut and tracer concentration show a good history match for this reservoir. The improved simulation model and the tracer module for this reservoir can be used for the prediction of future performance of the reservoir and interpretation of the tracer behaviour in the reservoir. (author)

Novel targets for positron emission tomography (PET) radiopharmaceutical tracers for visualization of neuroinflammation

Science.gov (United States)

Shchepetkin, I.; Shvedova, M.; Anfinogenova, Y.; Litvak, M.; Atochin, D.

2017-08-01

Non-invasive molecular imaging techniques can enhance diagnosis of neurological diseases to achieve their successful treatment. Positron emission tomography (PET) imaging can identify activated microglia and provide detailed functional information based on molecular biology. This imaging modality is based on detection of isotope labeled tracers, which emit positrons. The review summarizes the developments of various radiolabeled ligands for PET imaging of neuroinflammation.

Flow visualization in superfluid helium-4 using He2 molecular tracers

Science.gov (United States)

Guo, Wei

Flow visualization in superfluid helium is challenging, yet crucial for attaining a detailed understanding of quantum turbulence. Two problems have impeded progress: finding and introducing suitable tracers that are small yet visible; and unambiguous interpretation of the tracer motion. We show that metastable He2 triplet molecules are outstanding tracers compared with other particles used in helium. These molecular tracers have small size and relatively simple behavior in superfluid helium: they follow the normal fluid motion at above 1 K and will bind to quantized vortex lines below about 0.6 K. A laser-induced fluorescence technique has been developed for imaging the He2 tracers. We will present our recent experimental work on studying the normal-fluid motion by tracking thin lines of He2 tracers created via femtosecond laser-field ionization in helium. We will also discuss a newly launched experiment on visualizing vortex lines in a magnetically levitated superfluid helium drop by imaging the He2 tracers trapped on the vortex cores. This experiment will enable unprecedented insight into the behavior of a rotating superfluid drop and will untangle several key issues in quantum turbulence research. We acknowledge the support from the National Science Foundation under Grant No. DMR-1507386 and the US Department of Energy under Grant No. DE-FG02 96ER40952.

Predictions of PuO2 and tracer compound release from ISV melts

International Nuclear Information System (INIS)

Cronenberg, A.W.; Callow, R.A.

1992-04-01

Two field tests were conducted at the Idaho National Engineering Laboratory (INEL) to assess in situ vitrification (ISV) suitability for long-term stabilization of buried radioactive waste. Both tests contained rare-earth oxide tracers (DY 2 O 3 , Yb 2 O 3 , and Tb 4 O 7 ) to simulate the presence of plutonium in the form of PuO 2 . In the first test, Intermediate Field Test (IFT)-l, approximately 4-% release of tracer material occurred during soil melting and associated off-gassing, while essentially nil release was observed for the second experiment (IFT-2) for which off-gassing was much reduced. This report presents an evaluation of the IFT test data in terms of governing release processes. Prediction of tracer release during ISV melting centered on an assessment of three potential transport mechanisms, (a) tracer diffusion through stagnant pool, (b) tracer transport by convective currents, and (c) tracer carry-off by escaping gas bubbles. Analysis indicates that tracer release by escaping gas is the dominant release mechanism, which is consistent with video records of gas bubble escape from the ISV melt surface. Quantitative mass transport predictions were also made for the IFT-I test conditions, indicating similarity between the 4-% release data and calculational results at viscosities of ∼ poise and tracer diffusivities of ∼10 -6 CM 2 /s. Since PuO 2 has similar chemical and transport (diffusivity) properties as the rare-earth tracers used in the rare earth tracers used in the IFT experiments, release of PuO 2 is predicted for similar off-gassing conditions. Reduced off-gassing during ISV would thus be expected to improve the overall retention of heavy-oxides within vitrified soil

Chapter 19. Blood and bone marrow. C. Blood platelet kinetics

International Nuclear Information System (INIS)

Najean, Y.

1975-01-01

The blood platelet life span was measured by labelling the circulating population in vivo and in vitro. DF 32 P labelling in vivo: DFP is a specific inhibitor of acetyl-cholinesterase and hence in vivo labels blood platelets in the same way as the red cells and white cells which contain this enzyme. Sodium chromate 51 Cr: this is the method used almost universally and the various stages were described. Several parameters were studied: the percentage of blood platelets in circulation, the aspect of the radioactivity decay curve, blood platelet production. Results obtained by the use of a medulla tracer, 75 Se selenomethionine, were also reported. Finally the practical use of the blood platelet kinetics measurements were demonstrated [fr

Development of Models to Simulate Tracer Tests for Characterization of Enhanced Geothermal Systems

Energy Technology Data Exchange (ETDEWEB)

Williams, Mark D.; Reimus, Paul; Vermeul, Vincent R.; Rose, Peter; Dean, Cynthia A.; Watson, Tom B.; Newell, D.; Leecaster, Kevin; Brauser, Eric

2013-05-01

A recent report found that power and heat produced from enhanced (or engineered) geothermal systems (EGSs) could have a major impact on the U.S energy production capability while having a minimal impact on the environment. EGS resources differ from high-grade hydrothermal resources in that they lack sufficient temperature distribution, permeability/porosity, fluid saturation, or recharge of reservoir fluids. Therefore, quantitative characterization of temperature distributions and the surface area available for heat transfer in EGS is necessary for the design and commercial development of the geothermal energy of a potential EGS site. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate this characterization. This project was initially focused on tracer development with the application of perfluorinated tracer (PFT) compounds, non-reactive tracers used in numerous applications from atmospheric transport to underground leak detection, to geothermal systems, and evaluation of encapsulated PFTs that would release tracers at targeted reservoir temperatures. After the 2011 midyear review and subsequent discussions with the U.S. Department of Energy Geothermal Technology Program (GTP), emphasis was shifted to interpretive tool development, testing, and validation. Subsurface modeling capabilities are an important component of this project for both the design of suitable tracers and the interpretation of data from in situ tracer tests, be they single- or multi-well tests. The purpose of this report is to describe the results of the tracer and model development for simulating and conducting tracer tests for characterizing EGS parameters.

Hydraulic characterisation of karst systems with man-made tracers

International Nuclear Information System (INIS)

Werner, A.

1998-01-01

Tracer experiments using man-made tracers are common in hydrogeological exploration of groundwater aquifers in karst systems. In the present investigation, a convection-dispersion model (multidispersion model with consideration of several flow paths) and a single-cleft model (consideration of the diffusion between the cleft and the surrounding rock matrix) were used for evaluating tracer experiments in the main hydrological system of the saturated zone of karst systems. In addition to these extended analytical solutions, a numerical transport model was developed for investigating the influence of the transient flow rate on the flow and transport parameters. Comparative evaluations of the model approaches for the evaluation of tracer experiments were made in four different karst systems: Danube-Aach, Paderborn, Slowenia and Lurbach, of which the Danube-Aach system was considered as the most important. The investigation also comprised three supplementary experiments in order to enable a complete hydraulic characterisation of the system. (orig./SR) [de

Fluorescence guided surgery and tracer-dose, fact or fiction?

International Nuclear Information System (INIS)

KleinJan, Gijs H.; Olmos, Renato A.V.; Bunschoten, Anton; Berg, Nynke S. van den; Klop, W.M.C.; Horenblas, Simon; Poel, Henk G. van der; Wester, Hans-Juergen; Leeuwen, Fijs W.B. van

2016-01-01

Fluorescence guidance is an upcoming methodology to improve surgical accuracy. Challenging herein is the identification of the minimum dose at which the tracer can be detected with a clinical-grade fluorescence camera. Using a hybrid tracer such as indocyanine green (ICG)- 99m Tc-nanocolloid, it has become possible to determine the accumulation of tracer and correlate this to intraoperative fluorescence-based identification rates. In the current study, we determined the lower detection limit of tracer at which intraoperative fluorescence guidance was still feasible. Size exclusion chromatography (SEC) provided a laboratory set-up to analyze the chemical content and to simulate the migratory behavior of ICG-nanocolloid in tissue. Tracer accumulation and intraoperative fluorescence detection findings were derived from a retrospective analysis of 20 head-and-neck melanoma patients, 40 penile and 20 prostate cancer patients scheduled for sentinel node (SN) biopsy using ICG- 99m Tc-nanocolloid. In these patients, following tracer injection, single photon emission computed tomography fused with computed tomography (SPECT/CT) was used to identify the SN(s). The percentage injected dose (% ID), the amount of ICG (in nmol), and the concentration of ICG in the SNs (in μM) was assessed for SNs detected on SPECT/CT and correlated with the intraoperative fluorescence imaging findings. SEC determined that in the hybrid tracer formulation, 41 % (standard deviation: 12 %) of ICG was present in nanocolloid-bound form. In the SNs detected using fluorescence guidance a median of 0.88 % ID was present, compared to a median of 0.25 % ID in the non-fluorescent SNs (p-value < 0.001). The % ID values could be correlated to the amount ICG in a SN (range: 0.003-10.8 nmol) and the concentration of ICG in a SN (range: 0.006-64.6 μM). The ability to provide intraoperative fluorescence guidance is dependent on the amount and concentration of the fluorescent dye accumulated in the lesion(s) of

Deuterium used as artificial tracer in column studies under saturated water flow conditions

Science.gov (United States)

Koeniger, P.; Geiges, M.; Leibundgut, Ch.

2003-04-01

In contrast to numerous investigations using deuterium as an environmental tracer, hydrological investigations with deuterium-labelled water are rather rare. Currently applications in groundwater studies are restricted due to increasing costs of spiking large water quantities but an application as intelligent tracer might be of advantage especially in combination with other tracers and under distinct environmental conditions. Therefore deuterium was applied as artificial tracer in column experiments that are well proved as a tool to characterise tracer behaviour in recent studies. Deuterium was tested in comparison to the more familiar conservative tracer fluorescein. Varying experimental conditions, e.g. column length (0.5, 1.0, 1.5 m), initial tracer concentration (0.01, 0.02, 0.2 mg) and flow velocity (1.5 to 6.0 m/d) were used to investigate tracer behaviour under saturated water flow conditions. Deuterium was analysed using an H/Device with chrome reduction connected to an isotope ratio mass spectrometer and expressed in relative concentrations [per mill V-SMOW]. Theoretical tracer breakthrough curves were calculated using a one dimensional dispersion model. The results indicate higher mean transport velocities and smaller dispersion for deuterium in all experiments. Due to different molecule properties that also determine the interaction of soil substrate and tracer, deuterium indicates a more conservative transport behaviour. Deuterium is non-toxic, completely soluble, chemically and biologically stable and not subject to light-influenced decay. Furthermore, it shows promise for investigations of water flow in the unsaturated zone, and of interactions of water in soil-plant-atmosphere systems. A further discussion of problems, together with possibilities for applying deuterium as an artificial tracer, will be presented.

Stable isotope tracers and exercise physiology: past, present and future.

Science.gov (United States)

Wilkinson, Daniel J; Brook, Matthew S; Smith, Kenneth; Atherton, Philip J

2017-05-01

Stable isotope tracers have been invaluable assets in physiological research for over 80 years. The application of substrate-specific stable isotope tracers has permitted exquisite insight into amino acid, fatty-acid and carbohydrate metabolic regulation (i.e. incorporation, flux, and oxidation, in a tissue-specific and whole-body fashion) in health, disease and response to acute and chronic exercise. Yet, despite many breakthroughs, there are limitations to 'substrate-specific' stable isotope tracers, which limit physiological insight, e.g. the need for intravenous infusions and restriction to short-term studies (hours) in controlled laboratory settings. In recent years significant interest has developed in alternative stable isotope tracer techniques that overcome these limitations, in particular deuterium oxide (D 2 O or heavy water). The unique properties of this tracer mean that through oral administration, the turnover and flux through a number of different substrates (muscle proteins, lipids, glucose, DNA (satellite cells)) can be monitored simultaneously and flexibly (hours/weeks/months) without the need for restrictive experimental control. This makes it uniquely suited for the study of 'real world' human exercise physiology (amongst many other applications). Moreover, using D 2 O permits evaluation of turnover of plasma and muscle proteins (e.g. dynamic proteomics) in addition to metabolomics (e.g. fluxomics) to seek molecular underpinnings, e.g. of exercise adaptation. Here, we provide insight into the role of stable isotope tracers, from substrate-specific to novel D 2 O approaches, in facilitating our understanding of metabolism. Further novel potential applications of stable isotope tracers are also discussed in the context of integration with the snowballing field of 'omic' technologies. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Application of the compartmental analysis theory to the studies of the kinetics of the rainfall infiltration in the unsaturated zone in Abadia de Goias

International Nuclear Information System (INIS)

Poli, D. de C.R.; Mesquita, C.H. de

1999-01-01

The compartmental analysis was used for evaluation of kinetic parameters of the rainfall infiltration and determination of ground water recharge in Abadia-Goiania-Brazil. A model containing 13 compartments was proposed to explain the water infiltration and the kinetics of the unsaturated zone. To validate the model, tracer injections were carried out at a representative site of the region, at a depth of 50 cm, below the root zone. Soil samples were taken 4,9 and 12 months after the injection. In the first compartment, one component of the evaporation (K 4,0 ) was considered and for the last compartment, one constant of removal for the water table (k 13,0 ). Compartments 1, 2 and 3 were added to the system to consider precipitation effect. The AnaComp program, developed at IPEN, was used to determine the transfer constants k i,j ( from compartment i to compartment j)were i and j range from 0 to 13. In this program the constants k i,j were determined by the nonlinear last squares method, using eigenvalues - eigenvectors routines or alternatively, the fourth order Runge-Kutta routine. In this compartment model, the radioactive tracer was introduced as a single pulse, into the 6th compartment (50 cm depth). This permits to characterize the tracer diffusion processes in the soil studied. The adopted model showed an explanation coefficient f 2 equal to 0.78, which is satisfactory for the methodology used. (author)

The ATLAS DDM Tracer monitoring framework

International Nuclear Information System (INIS)

Zang Dongsong; Garonne, Vincent; Barisits, Martin; Lassnig, Mario; Andrew Stewart, Graeme; Molfetas, Angelos; Beermann, Thomas

2012-01-01

The DDM Tracer monitoring framework is aimed to trace and monitor the ATLAS file operations on the Worldwide LHC Computing Grid. The volume of traces has increased significantly since the framework was put in production in 2009. Now there are about 5 million trace messages every day and peaks can be near 250Hz, with peak rates continuing to climb, which gives the current structure a big challenge. Analysis of large datasets based on on-demand queries to the relational database management system (RDBMS), i.e. Oracle, can be problematic, and have a significant effect on the database's performance. Consequently, We have investigated some new high availability technologies like messaging infrastructure, specifically ActiveMQ, and key-value stores. The advantages of key value store technology are that they are distributed and have high scalability; also their write performances are usually much better than RDBMS, all of which are very useful for the Tracer monitoring framework. Indexes and distributed counters have been also tested to improve query performance and provided almost real time results. In this paper, the design principles, architecture and main characteristics of Tracer monitoring framework will be described and examples of its usage will be presented.

Atmospheric Gas Tracers in Groundwater: Theory, Sampling. Measurement and Interpretation

International Nuclear Information System (INIS)

Bayari, C.S.

2002-01-01

Some of the atmospheric gasses posses features that are sought in an environmental tracer of hydrogeologic interest. Among these, chlorofluorocarbons, sulfur hegzafluoride, carbon tetrachloride, methyl chloroform, krypton-85 etc. have found increasing use in groundwater age dating studies during the last ten years. This paper explains the theory of their use as tracer and discusses the major concerns as related to their sampling and analyses. Factors affecting their applicability and the approach to interpret tracer gas data is briefly outlined

2007 California Aerosol Study: Evaluation of δ15N as a Tracer Of NOx Sources and Chemsitry

Science.gov (United States)

Katzman, T. L.

2017-12-01

Although stable isotopes of N are commonly used as a source tracer, how this tracer is applied is a point of contention. The "source" hypothesis argues that the δ15N value of NO3- reflects the δ15N value of NOx source inputs into the environment, and any observed variation is solely the result of differences in source contributions. Conversely, the "chemistry" hypothesis argues that N isotopes are influenced by chemical reactions, atmospheric or biologic processing, and post-depositional effects. Previous studies often apply the source hypothesis, writing off the chemistry hypothesis as "minor," but others have noted the impact chemistry should has on δ15N values. Given the known complications, this work seeks to assess the use of stable isotopes as tracers, specifically, the assumption that the δ15N value is a tracer of source alone without significant influence from chemical reactions. If the "source" hypothesis is correct, source emission data, known source δ15N values, and isotope mass balance should be able to approximate measured δ15NNO3 values and determine the δ15N value associated with wildfire derived NOx, which is currently unknown. Significant deviations from observed values would support the significance of equilibrium and kinetic isotope effects associated with chemical reactions and processing in the atmosphere. Aerosols collected in during 2007, emission data, and isotopic analysis were utilized to determine the utility of δ15N as tracer of NOx sources. San Diego, California is a coastal urban area influenced by sea salt aerosols, anthropogenic combustion emissions, and seasonal wildfires. Wildfires also have a significant influence on local atmospheric chemistry and 2007 was notable for being one of the worst fire seasons in the San Diego region on record. Isotopic analysis of collected NO3- has suggested that source δ15N values are likely not conserved as NOx is oxidized into NO3-. Given known source contributions and known δ15N values

The PurdueTracer: An Energy-Efficient Human-Powered Hydraulic Bicycle with Flexible Operation and Software Aids

Directory of Open Access Journals (Sweden)

Gianluca Marinaro

2018-01-01

Full Text Available Hydrostatic transmissions (HT are widely applied to heavy-duty mobile applications because of the advantages of layout flexibility, power to weight ratio, and ease of control. Though applications of fluid power in light-duty vehicles face challenges, including the unavailability of off-the-shelf components suitable to the power scale, there are potential advantages for HTs in human-powered vehicles, such as bicycles, the most important one being the energy-saving advantage achievable through regenerative braking in a hybrid HT. This paper describes an innovative design for a hydraulic hybrid bicycle, i.e., the PurdueTracer. The PurdueTracer is an energy-efficient human-powered hydraulic bicycle with flexible operation and software aids. An open-circuit hydraulic hybrid transmission allows PurdueTracer to operate in four modes: Pedaling, Charging, Boost, and Regeneration, to satisfy users’ need for different riding occasions. An aluminum chassis that also functions as a system reservoir was customized for the PurdueTracer to optimize the durability, riding comfort, and space for components. The selection of the hydraulic components was performed by creating a model of the bicycle in AMESim simulation software and conducting a numerical optimization based on the model. The electronic system equipped users with informative feedback showing the bicycle performance, intuitive execution of functions, and comprehensive guidance for operation. This paper describes the design approach and the main results of the PurdueTracer, which also won the 2017 National Fluid Power Association Fluid Power Vehicle Challenge. This championship serves to prove the excellence of this vehicle in terms of effectiveness, efficiency, durability, and novelty.

Sistem Pre Kompilasi Data Tracer Studi Online Ditjen Belmawa Ristekdikti (Studi Kasus: Politeknik Harapan Bersama

Directory of Open Access Journals (Sweden)

Very Kurnia Bakti

2017-01-01

Full Text Available Tracer studi merupakan salah satu upaya yang diharapkan dapat menyediakan informasi untuk mengevaluasi hasil pendidikan di Politeknik Harapan Bersama dari kuisioner yang diberikan kepada alumni. Kegiatan tracer studi ini sudah dilaksanakan secara online, namun masih terdapat kendala pada bagian sistem yang digunakan saat ini, hal tersebut menyebabkan Politeknik Harapan Bersama tidak dapat melaporkan / mengunggah hasil tracer studi kepada Ditjen Belmawa Ristekdikti, dimana form kuisioner dan data export tracer studi yang dihasilkan berbeda dengan kebutuhan seperti yang tercantum pada surat edaran No. 313/B/SE/2016 tentang pelaksanaan tracer studi di tingkat perguruan tinggi. Mengingat pentingnya tracer studi sebagai umpan balik bagi Politeknik Harapan Bersama, maka perlu solusi untuk mengatasi kekurangan sistem ini. Dengan merubah sistem yang ada dengan sistem tracer studi yang baru merupakan solusi yang tepat dalam permasalahan ini. Sistem tracer studi yang baru mampu menghasilkan data tracer studi alumni dan pengisian form kuisioner sesuai dengan standar Ditjen Belmawa Ristekdikti yang dapat diunggah sistem tracer studi ristekdikti.

IMAGE Project: Results of Laboratory Tests on Tracers for Supercritical Conditions.

Science.gov (United States)

Brandvoll, Øyvind; Opsahl Viig, Sissel; Nardini, Isabella; Muller, Jiri

2016-04-01

The use of tracers is a well-established technique for monitoring dynamic behaviour of water and gas through a reservoir. In geothermal reservoirs special challenges are encountered due to high temperatures and pressures. In this work, tracer candidates for monitoring water at supercritical conditions (temperature > 374°C, pressure ca 218 bar), are tested in laboratory experiments. Testing of tracers at supercritical water conditions requires experimental set-ups which tolerate harsh conditions with respect to high temperature and pressure. In addition stringent HES (health, environment and safety) factors have to be taken into consideration when designing and performing the experiments. The setup constructed in this project consists of a pressure vessel, high pressure pump, instrumentation for pressure and temperature control and instrumentation required for accurate sampling of tracers. In order to achieve accurate results, a special focus has been paid to the development of the tracer sampling technique. Perfluorinated cyclic hydrocarbons (PFCs) have been selected as tracer candidates. This group of compounds is today commonly used as gas tracers in oil reservoirs. According to the literature they are stable at temperatures up to 400°C. To start with, five PFCs have been tested for thermal stability in static experiments at 375°C and 108 bar in the experimental setup described above. The tracer candidates will be further tested for several months at the relevant conditions. Preliminary results indicate that some of the PFC compounds show stability after three months. However, in order to arrive at conclusive results, the experiments have to be repeated over a longer period and paying special attention to more accurate sampling procedures.

The use of 123I-labeled heptadecanoic acid (HDA) as metabolic tracer: preliminary report.

Science.gov (United States)

Dudczak, R; Kletter, K; Frischauf, H; Losert, U; Angelberger, P; Schmoliner, R

1984-01-01

The feasibility of using 123I-heptadecanoic acid (HDA) as a metabolic tracer was studied. Different administration routes of HDA were compared. An intracoronary bolus injection was given to calves (n = 3), and an intravenous injection was given to patients (n = 4). In addition, we examined the influence of 4-h halothane anesthesia in calves and in patients the impact of an insulin (1.5 IU/kg) + glucose (1.5 g/kg) infusion on the myocardial kinetics of HDA. Data were accumulated with a scintillation probe in calves (t = 50 min) and a gamma camera in patients (t = 70 min). In calves after an intracoronary bolus injection of HDA the myocardial time-activity curve could be described by two exponentials. The mean elimination half-time of the initial phase (ta 1/2) was 7.3 min and that of the second phase (tb 1/2) was 35 min. The ratio of the size of the initial and second component at to was 0.93. Halothane anesthesia prolonged the elimination half-times and reduced the component ratio. The biphasic behavior of the myocardial time-activity curve was maintained in patients after intravenous administration of HDA under basal conditions (initial ta 1/2 = 8.4 min). However, during infusion of insulin + glucose the decline in the myocardial activity was prolonged and monoexponential. This data shows that insulin glucose, interfering with fatty acid metabolism, influences the myocardial washout of HDA, and thus support its use as a metabolic tracer.

Transport of Perfluorocarbon Tracers in the Cranfield Geological Carbon Sequestration Project

Science.gov (United States)

Moortgat, J.; Soltanian, M. R.; Amooie, M. A.; Cole, D. R.; Graham, D. E.; Pfiffner, S. M.; Phelps, T.

2017-12-01

A field-scale carbon dioxide (CO2) injection pilot project was conducted by the Southeast Regional Sequestration Partnership (SECARB) at Cranfield, Mississippi. Two associated campaigns in 2009 and 2010 were carried out to co-inject perfluorocarbon tracers (PFTs) and sulfur hexafluoride (SF6) with CO2. Tracers in gas samples from two observation wells were analyzed to construct breakthrough curves. We present the compiled field data as well as detailed numerical modeling of the flow and transport of CO2, brine, and introduced tracers. A high-resolution static model of the formation geology in the Detailed Area Study (DAS) was used in order to capture the impact of connected flow pathways created by fluvial channels on breakthrough curves and breakthrough times of PFTs and SF6 tracers. We use the cubic-plus-association (CPA) equation of state, which takes into account the polar nature of water molecules, to describe the phase behavior of CO2-brine-tracer mixtures. We show how the combination of multiple tracer injection pulses with detailed numerical simulations provide a powerful tool in constraining both formation properties and how complex flow pathways develop over time.

The propagation of Escherichia Coli and of conservative tracers. A comparison

International Nuclear Information System (INIS)

Alexander, I.; Seiler, K.P.

1982-01-01

The propagation of Escherichia Coli (ATCC 11229, Gelsenkirchen) is compared with that of conservative tracers in groundwater. The experiments were performed with injection quantities of 10 7 , 10 8 , 10 10 and 10 11 of Escherichia Coli. Both, bacteria and conservative tracers pass their maximum at the same instant in the observation gauges. With injection quantities of more than 10 8 , the propagation of the Escherichia Coli sets in at the same time as it begins with the dyes. When the quantities range below 10 8 , the propagation begins after that of conservative tracers, because Coli bacteria were measured with a lower degree of detecting sensitivity than the tracers. With Coli injection quantities ranging above 10 10 , an increased filtering of these bacteria can be observed. Coli bacteria propagate more laterally than conservative tracers, however it could not be proved that this lateral propagation depends on the bacteria concentration. (orig.) [de

Methods and systems using encapsulated tracers and chemicals for reservoir interrogation and manipulation

Science.gov (United States)

Roberts, Jeffery; Aines, Roger D; Duoss, Eric B; Spadaccini, Christopher M

2014-11-04

An apparatus, method, and system of reservoir interrogation. A tracer is encapsulating in a receptacle. The receptacle containing the tracer is injected into the reservoir. The tracer is analyzed for reservoir interrogation.

Contamination tracer testing with seabed drills: IODP Expedition 357

Science.gov (United States)

Orcutt, Beth N.; Bergenthal, Markus; Freudenthal, Tim; Smith, David; Lilley, Marvin D.; Schnieders, Luzie; Green, Sophie; Früh-Green, Gretchen L.

2017-11-01

IODP Expedition 357 utilized seabed drills for the first time in the history of the ocean drilling program, with the aim of collecting intact sequences of shallow mantle core from the Atlantis Massif to examine serpentinization processes and the deep biosphere. This novel drilling approach required the development of a new remote seafloor system for delivering synthetic tracers during drilling to assess for possible sample contamination. Here, we describe this new tracer delivery system, assess the performance of the system during the expedition, provide an overview of the quality of the core samples collected for deep biosphere investigations based on tracer concentrations, and make recommendations for future applications of the system.

Fluorescence tracers as a reference for pesticide transport in wetland systems

Science.gov (United States)

Lange, Jens; Passeport, Elodie; Tournebize, Julien

2010-05-01

Two different fluorescent tracers, Uranine (UR) and Sulforhodamine (SRB), were injected as a pulse into surface flow wetlands. Tracer breakthrough curves were used to document hydraulic efficiencies, peak attenuation and retention capacities of completely different wetland systems. The tracers were used as a reference to mimic photolytic decay (UR) and sorption (SRB) of contaminants, since a real herbicide (Isoproturon, IPU) was injected in parallel to UR and SRB. Analysis costs limited IPU sampling frequency and single samples deviated from the tracer breakthrough curves. Still, a parallel behavior of IPU and SRB could be observed in totally different wetland systems, including underground passage through drainage lines. Similar recovery rates for IPU and SRB confirmed this observation. Hence, SRB was found to be an appropriate reference tracer to mimic the behavior of mobile pesticides (low KOC, without degradation) in wetland systems and the obtained wetland characteristics for SRB may serve as an indication for contaminant retention. Owing to the properties of IPU, the obtained results should be treated as worst case scenarios for highly mobile pesticides. A comparison of six different wetland types suggested that non-steady wetland systems with large variation in water level may temporally store relatively large amounts of tracers (contaminants), partly in areas that are not continuously saturated. This may lead to an efficient attenuation of peak concentrations. However, when large parts of these systems are flushed by natural storm events, tracers (contaminants) may be re-mobilized. In steady systems vegetation density and water depth were found to be the most important factors for tracer/contaminant retention. Illustrated by SRB, sorption on sediments and vegetation was a quick, almost instantaneous process which lead to considerable tracer losses even at high flow velocities and short contact times. Shallow systems with dense vegetation appeared to be the

Natural tracer profiles across argillaceous formations: the Claytrac project

International Nuclear Information System (INIS)

Mazurek, M.; Alt-Epping, P.; Gimi, Th.; Niklaus Waber, H.; Bath, A.; Gimmi, Th.

2009-01-01

Disposal of high-level radioactive waste and spent nuclear fuel in engineered facilities, or repositories, located deep underground in suitable geological formations is being developed worldwide as the reference solution to protect humans and the environment both now and in the future. An important aspect of assessing the long-term safety of deep geological disposal is developing a comprehensive understanding of the geological environment in order to define the initial conditions for the disposal system as well as to provide a sound scientific basis for projecting its future evolution. The transport pathways and mechanisms by which contaminants could migrate in the surrounding host rock are key elements in any safety case. Relevant experiments in laboratories or underground test facilities can provide important information, but the challenge remains in being able to extrapolate the results to the spatial and temporal scales required for performance assessment, which are typically tens to hundreds of metres and from thousands to beyond a million years into the future. Profiles of natural tracers dissolved in pore water of argillaceous rock formations can be considered as large-scale and long-term natural experiments which enable the transport properties to be characterised. The CLAYTRAC Project on Natural Tracer Profiles Across Argillaceous Formations was established by the NEA Clay Club to evaluate the relevance of natural tracer data in understanding past geological evolution and in confirming dominant transport processes. Data were analysed for nine sites to support scientific understanding and development of geological disposal. The outcomes of the project show that, for the sites and clay-rich formations that were studied, there is strong evidence that solute transport is controlled mainly by diffusion. The results can improve site understanding and performance assessment in the context of deep geological disposal and have the potential to be applied to other

On-line measurements of liquid carry-over from scrubbers using radioactive tracers

Energy Technology Data Exchange (ETDEWEB)

Haugan, A; Hassfjell, S [Institute for Energy Technology, Kjeller (Norway); Finborud, A [Mator, Porsgrunn (Norway)

2004-07-01

A method to measure liquid carry-over from scrubbers using gamma-emitting tracers is described and results from field tests at two onshore installations are presented. One water/1,2-ethanediol (MEG) and two hydrocarbon liquid (condensate) tracers have been used in the tests. One of the condensate tracers deposited to some extent inside the process pipe, while the other had a too high vapor pressure. The water/MEG tracer showed no MEG carry-over while the carry-over of MEG was documented to be considerable. (author)

On-line measurements of liquid carry-over from scrubbers using radioactive tracers

International Nuclear Information System (INIS)

Haugan, A.; Hassfjell, S.; Finborud, A.

2004-01-01

A method to measure liquid carry-over from scrubbers using gamma-emitting tracers is described and results from field tests at two onshore installations are presented. One water/1,2-ethanediol (MEG) and two hydrocarbon liquid (condensate) tracers have been used in the tests. One of the condensate tracers deposited to some extent inside the process pipe, while the other had a too high vapor pressure. The water/MEG tracer showed no MEG carry-over while the carry-over of MEG was documented to be considerable. (author)

Use of tracers to quantify subsurface flow through a mining pit.

Science.gov (United States)

Schladow, S Geoffrey; Clark, Jordan F

2008-12-01

Three independent tracer experiments were conducted to quantify the through-flow of water from Herman Pit, an abandoned mercury (Hg) mine pit adjacent to Clear Lake, California, USA. The tracers used were Rhodamine-WT, sulfur hexafluoride, and a mixture of sulfur hexafluoride and neon-22. The tracers were injected into Herman Pit, a generally well-mixed water body of approximately 81,000 m2, and the concentrations were monitored in the mine pit, observation wells, and the lake for 2-3 months following each injection. The results for all three experiments showed that the tracer arrived at certain observation wells within days of injection. Comparing all the well data showed a highly heterogeneous response, with a small number of wells showing this near-instantaneous response and others taking months before the tracer was detectable. Tracer was also found in the lake on four occasions over a one-month period, too few to infer any pattern but sufficient to confirm the connection of the two water bodies. Using a simple mass balance model it was possible to determine the effective loss rate through advection for each of the tracers and with this to estimate the through-flow rate. The through-flow rate for all three experiments was approximately 630 L/s, at least 1-2 orders of magnitude larger than previous estimates, all of which had been based on geochemical inferences or other indirect measures of the pit through-flow.

GTS-LCS, in-situ experiment 2. Modeling of tracer test 09-03

International Nuclear Information System (INIS)

Manette, M.; Saaltink, M.W.; Soler, J.M.

2015-02-01

Within the framework of the GTS-LCS project (Grimsel Test Site - Long-Term Cement Studies), an in-situ experiment lasting about 5 years was started in 2009 to study water-cement-rock interactions in a fractured granite. Prior to the experiment, a tracer test was performed to characterize the initial flow and transport properties of the rock around the experimental boreholes. This study reports on the model interpretation of tracer test 09-03. The calculations were performed by means of a two-dimensional model (homogeneous fracture plane including 3 boreholes) using the Retraso-CodeBright software package. In the tracer test, Grimsel groundwater containing the tracer (uranine) was circulated in the emplacement borehole during 43 days (zero injection flow rate). Circulation continued without tracer afterwards. Water was extracted at the observation and extraction boreholes. Results from a model sensitivity analysis comparing model results with measured tracer concentrations showed 3 cases where the evolution of tracer concentrations in the 3 different boreholes was satisfactory. In these cases a low-permeability skin affected the emplacement and observation boreholes. No skin appeared to affect the extraction borehole. The background hydraulic gradient seems to have no effect on the results of the tracer test. These results will be applied in the calculation of the initial flow field for the reactive transport phase of in-situ experiment 2 (interaction between pre-hardened cement and fractured granite at Grimsel). (orig.)

Flow-rate measurement using radioactive tracers and transit time method

International Nuclear Information System (INIS)

Turtiainen, Heikki

1986-08-01

The transit time method is a flow measurement method based on tracer techniques. Measurement is done by injecting to the flow a pulse of tracer and measuring its transit time between two detection positions. From the transit time the mean flow velosity and - using the pipe cross section area - the volume flow rate can be calculated. When a radioisotope tracer is used the measurement can be done from outside the pipe and without disturbing the process (excluding the tracer injection). The use of the transit time method has been limited because of difficulties associated with handling and availability of radioactive tracers and lack of equipment suitable for routine use in industrial environments. The purpose of this study was to find out if these difficulties may be overcome by using a portable isotope generator as a tracer source and automating the measurement. In the study a test rig and measuring equipment based on the use of a ''1''3''7Cs/''1''3''7''''mBa isotope generator were constructed. They were used to study the accuracy and error sources of the method and to compare different algorithms to calculate the transit time. The usability of the method and the equipment in industrial environments were studied by carrying out over 20 flow measurements in paper and pulp mills. On the basis of the results of the study, a project for constructing a compact radiatracer flowmeter for industrial use has been started. The application range of this kind of meter is very large. The most obvious applications are in situ calibration of flowmeters, material and energy balance studies, process equipment analyses (e.g. pump efficiency analyses). At the moment tracer techniques are the only methods applicable to these measurements on-line and with sufficient accuracy

Purification of tracer for somatomedin C radioimmunoassay by hydrophobic interaction chromatography

Energy Technology Data Exchange (ETDEWEB)

Baxter, R.C.; Brown, A.S.

1982-03-01

A tracer for use in the somatomedin C radiommunoassay by hydrophobic interaction chromatography was purified. Material showing greatest immunoreactivity binds to Octyl Sepharose CL-4B (Pharmacia) in a buffer mixture consisting of 130 mL of acetonitrile and 870 mL of 0.1 mol/L NH/sub 4/HCO/sub 3/, pH 7.8, but is eluted by increasing the acetonitrile content to 180 mL/L. As compared with tracer purified by binding to specific antiserum in liquid phase, precipitating the complex with second antibody, and then dissociating by gel chromatography at acid pH, this tracer shows equal immunoreactivity against specific somatomedin C antiserum. Either preparation allows excellent discrimination between extracts of normal, acromegalic, and hypopituitary plasma samples; thus either is suitable for use in the somatomedin C radioimmunoassay. Tracer purification by hydrophobic interaction chromatography is rapid and inexpensive. It may be useful in preparing highly immunoreactive tracers for other peptide radioimmunoassays.

Transfer function analysis of positron-emitting tracer imaging system (PETIS) data

International Nuclear Information System (INIS)

Keutgen, N.; Matsuhashi, S.; Mizuniwa, C.; Ito, T.; Fujimura, T.; Ishioka, N.S.; Watanabe, S.; Sekine, T.; Uchida, H.; Hashimoto, S.

2002-01-01

Quantitative analysis of the two-dimensional image data obtained with the positron-emitting tracer imaging system (PETIS) for plant physiology has been carried out using a transfer function analysis method. While a cut leaf base of Chinese chive (Allium tuberosum Rottler) or a cut stem of soybean (Glycine max L.) was immersed in an aqueous solution containing the [ 18 F] F - ion or [ 13 N]NO 3 - ion, tracer images of the leaf of Chinese chive and the trifoliate of soybean were recorded with PETIS. From the time sequence of images, the tracer transfer function was estimated from which the speed of tracer transport and the fraction moved between specified image positions were deduced

Distribution kinetics of 3H-labelled p-phenylene diamine - - a hair dye

International Nuclear Information System (INIS)

Rehani, M.M.; Jain, I.S.; Sharma, S.K.

1981-01-01

The distribution kinetics of the 3 H-labelled p-phenylene diamine (a hair dye compound), was studied when administered iv and when applied percutaneously. The tracer experiments in rabbits after iv administration showed a biphasic blood clearance with half life values of 24 min and 43.5 h and quick-percutaneous absorption. The tissue distribution pattern investigated after iv and percutaneous administration in 16 different tissues and also in blood did not demonstrate any target organ for selective localisation of the dye. Not more than 0.06 percent of the iv administered radioactivity was measured per 10 mg of any tissue at 12th day. (author)

Fifty years of radiochemical tracers

International Nuclear Information System (INIS)

Evans, E.A.

1992-01-01

During the past 50 years radiochemical tracers, usually in the form of isotopically labelled organic compounds, have been essential tools to further advance our knowledge at the frontiers of a great variety of scientific developments in the life sciences. This plenary lecture reviews necessarily selected highlights in the synthesis and applications of such radiochemical tracers. Included are examples where important advances, made possible by using radiochemicals, have contributed to improving the quality of life on this planet. The principal radioisotopes involved, 14 C, 3 H, 35 S, 32 P, 125 I, are all relatively safe to handle and are commercially available at maximum theoretical specific activity (carrier free). The compounds labeled with these radioisotopes are used in many fields of research which include biosynthesis and biotechnology studies, cell biology, drug metabolism, clinical research and environmental applications, and are briefly reviewed. (author). 55 refs

Statistical dynamic imaging of RI-labeled tracer from list-mode PET data

International Nuclear Information System (INIS)

Tanimoto, Michiaki; Kuroda, Yoshihiro; Oshiro, Osamu; Watabe, Hiroshi; Kuroda, Tomohiro

2009-01-01

Positron emission tomography (PET) can be used in physiological analysis to illustrate physiological states by visualizing the accumulation of radioisotope (RI)-labeled tracer in specific organs or tissues. PET obtains spatio-temporal statistics in the form of list-mode data. However, conventional imaging techniques, which sum up list-mode data over a given time period, cannot depict detailed temporal dynamics of the RI-labeled tracer. In this study, a spatio-temporal analysis approach was employed to visualize the temporal flow dynamics of RI-labeled tracer from the obtained list-mode data. Experiments to assess the visualization of simulated RI-labeled tracer dynamics as well as RI-labeled tracer dynamics in a vascular phantom showed that the proposed method successfully depicted detailed temporal flow dynamics that could not be visualized using conventional methods. (author)

Characterization of eco-friendly fluorescent nanoparticle-doped tracers for environmental sensing

International Nuclear Information System (INIS)

Tauro, Flavia; Rapiti, Emiliano; Al-Sharab, Jafar F.; Ubertini, Lucio; Grimaldi, Salvatore; Porfiri, Maurizio

2013-01-01

Particle tracers are extensively used in quantitative flow visualization and environmental sensing. In this paper, we provide a thorough characterization of the novel eco-friendly fluorescent particle tracers formulated in Tauro et al. (AIP Adv 3(3): 032108, 2013). The tracers are synthesized from natural beeswax and are functionalized by encapsulating nontoxic fluorophore nanoparticles in the beads’ matrix through an inexpensive thermal procedure. Visibility and durability studies are conducted through a wide array of techniques to investigate the tracers’ surface morphological microfeatures, crystal nature and size, chemical composition, fluorophore incorporation into the beeswax matrix, and fluorescence response under severe settings resembling exposure to natural environments. Our findings demonstrate that fluorescent nanoparticles ranging from 1.51 to 3.73 nm are homogeneously distributed in the superficial layer (12 nm) of the tracers. In addition, fluorescence emissions are observed up to 26 days of continuous exposure of the tracers to high energy radiation. To demonstrate the particles’ use in environmental flow sensing, a set of proof of concept outdoor tests are conducted, in which image analysis tools are utilized for detecting the fluorescent tracers. Experimental results suggest that fluorescent microparticles deployed in high flow-rate flows (2 m/s) and under direct sunlight can be sensed through commercially available cameras (frame rate set to 30 Hz)

Unit vent airflow measurements using a tracer gas technique

Energy Technology Data Exchange (ETDEWEB)

Adams, D.G. [Union Electric Company, Fulton, MO (United States); Lagus, P.L. [Lagus Applied Technology, Inc., San Diego, CA (United States); Fleming, K.M. [NCS Corp., Columbus, OH (United States)

1997-08-01

An alternative method for assessing flowrates that does not depend on point measurements of air flow velocity is the constant tracer injection technique. In this method one injects a tracer gas at a constant rate into a duct and measures the resulting concentration downstream of the injection point. A simple equation derived from the conservation of mass allows calculation of the flowrate at the point of injection. Flowrate data obtained using both a pitot tube and a flow measuring station were compared with tracer gas flowrate measurements in the unit vent duct at the Callaway Nuclear Station during late 1995 and early 1996. These data are presented and discussed with an eye toward obtaining precise flowrate data for release rate calculations. The advantages and disadvantages of the technique are also described. In those test situations for which many flowrate combinations are required, or in large area ducts, a tracer flowrate determination requires fewer man-hours than does a conventional traverse-based technique and does not require knowledge of the duct area. 6 refs., 10 figs., 6 tabs.

Natural stream flow-rates measurements by tracer techniques

International Nuclear Information System (INIS)

Cuellar Mansilla, J.

1982-01-01

This paper presents the study of the precision obtained measuring the natural stream flow rates by tracer techniques, especially when the system presents a great slope and a bed constituted by large and extended particle size. The experiences were realized in laboratory pilot channels with flow-rates between 15 and 130 [1/s]; and in natural streams with flow-rates from 1 to 25 m 3 /s. Tracer used were In-133m and Br-82 for laboratory and field measurements respectively. In both cases the tracer was injected as a pulse and its dilution measured collecting samples in the measured section, at constant flow-rates, of 5[1] in laboratory experiences and 60[1] of water in field experiences. Precisions obtained at a 95% confidence level were about 2% for laboratory and 3% for field. (I.V.)

Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain site characterization project: Quality Assurance Project Plan, Revision 1

International Nuclear Information System (INIS)

Stetzenbach, K.J.

1993-01-01

The purpose of this work is to identify and characterize candidate conservative organic tracers for use as hydrologic tracers for experiments to be conducted at the Yucca Mountain C-well complex. During this quarter the main effort was directed towards rewriting the quality assurance program in preparation for a review and audit by the USGS. However, due to budget constraints the review and audit were not carried out. The tracer QA plan and standard operating procedures (SOPs) were revised and copies are included in the report. Instrumental problems were encountered and corrected with the addition of new integration and sample control software. In the sampling, there was an unexplained peak in the chromatograms of the tracers being tested in the light tuff. This was not correctable and these experiments will be repeated in the next quarter

Kinetics from Replica Exchange Molecular Dynamics Simulations.

Science.gov (United States)

Stelzl, Lukas S; Hummer, Gerhard

2017-08-08

Transitions between metastable states govern many fundamental processes in physics, chemistry and biology, from nucleation events in phase transitions to the folding of proteins. The free energy surfaces underlying these processes can be obtained from simulations using enhanced sampling methods. However, their altered dynamics makes kinetic and mechanistic information difficult or impossible to extract. Here, we show that, with replica exchange molecular dynamics (REMD), one can not only sample equilibrium properties but also extract kinetic information. For systems that strictly obey first-order kinetics, the procedure to extract rates is rigorous. For actual molecular systems whose long-time dynamics are captured by kinetic rate models, accurate rate coefficients can be determined from the statistics of the transitions between the metastable states at each replica temperature. We demonstrate the practical applicability of the procedure by constructing master equation (Markov state) models of peptide and RNA folding from REMD simulations.

Contamination tracer testing with seabed drills: IODP Expedition 357

Directory of Open Access Journals (Sweden)

B. N. Orcutt

2017-11-01

Full Text Available IODP Expedition 357 utilized seabed drills for the first time in the history of the ocean drilling program, with the aim of collecting intact sequences of shallow mantle core from the Atlantis Massif to examine serpentinization processes and the deep biosphere. This novel drilling approach required the development of a new remote seafloor system for delivering synthetic tracers during drilling to assess for possible sample contamination. Here, we describe this new tracer delivery system, assess the performance of the system during the expedition, provide an overview of the quality of the core samples collected for deep biosphere investigations based on tracer concentrations, and make recommendations for future applications of the system.

Environmental Monitoring of Agro-Ecosystem Using Environmental Isotope Tracer Technology

International Nuclear Information System (INIS)

Chung, Byung Yeoup; Kim, Jae Sung; Cho, Jae Young

2004-10-01

This report has provided the counterparts the knowledge and skills on the use of environmental isotope tracer technology for obtaining valuable information on agricultural non-point pollution source in agro-ecosystem. The contamination from agricultural watersheds has been brought into attention as a potential contaminant of streams and tributaries, since majority of them caused water quality degradation, eutrophication of reservoir and negative effect on agro-environment. To prevent the contamination from these watersheds, it is necessary to find out the source of the contamination. However, accurate contaminants outflows from various types of non-point sources have not yet been elucidated due to the fact that the extent of non-point source contaminants related to uncontrollable climatic events and irrigation conditions may differ greatly from place to place and year to year. The dominant use of isotopes in environmental ecosystem research in the last few decades has been to trace sources of waters and solutes. The environmental isotope tracer technology using stable isotopes such as oxygen, hydrogen, carbon, nitrogen, and sulfur has extensively been used for tracing the fate of environmental pollutants and for identification of environmental pollutants sources in agro-ecosystems

Interpretation of the tracer testing conducted in the Leuggern borehole

International Nuclear Information System (INIS)

McNeish, J.A.; Andrews, R.W.; Vomvoris, S.

1990-12-01

Tracer testing was conducted in the Leuggern borehole from July to December 1988 to evaluate the hydraulic properties of the crystalline host rock. The tested interval was an approximately 50 m section of fractured crystalline rock at a depth of greater than 1,600 m. The testing consisted of three tracer injection/recovery periods (uranin - 44 days, eosin - 30 days, and naphtionat -14 days), which utilized tracer injection/circulation rates, ranging between 25 and 50 ml/min. During these testing periods, tracer was injected in either of two 1/4 flow lines ported at the top or bottom of the interval and recovered from the other. Following the three tracer injection periods, a natural outflow tracer recovery test was conducted from the central tubing at an average outflow of 12 l/min. The central tubing was ported near the center of the test interval. Data collected during the testing periods included: continuous monitoring of fluid temperature, injection pressure, and electrical conductivity as well as discrete measurement of flow rates, electrical conductivity, fluid temperature, and tracer concentration. Testing results indicate a downward vertical flow of approximately 195-225 ml/min in the isolated interval, from an upper fracture inflow zone to a lower fracture outflow zone. Through analysis of the dilution levels of uranin and eosin during the injection/recovery periods, and review of field data, the top of the upper inflow zone was determined to be approximately 13 m below the top flow line and the bottom of the outflow zone to be approximately 3 to 5 meters above the bottom flow line. The calculated transmissivity value of 6E-05 m 2 /s from observed outflow rate and pressure recovery data, is consistent with results derived from previous hydraulic packer testing in the interval. The effective porosity was determined to be 0.1. Dispersion coefficient values ranged from 1.0 m to 5.0 m. The lateral hydraulic gradient value calculated from tracer recovery

Tracer technology modeling the flow of fluids

CERN Document Server

Levenspiel, Octave

2012-01-01

A vessel’s behavior as a heat exchanger, absorber, reactor, or other process unit is dependent upon how fluid flows through the vessel.  In early engineering, the designer would assume either plug flow or mixed flow of the fluid through the vessel.  However, these assumptions were oftentimes inaccurate, sometimes being off by a volume factor of 100 or more.  The result of this unreliable figure produced ineffective products in multiple reaction systems.   Written by a pioneering researcher in the field of chemical engineering, the tracer method was introduced to provide more accurate flow data.  First, the tracer method measured the actual flow of fluid through a vessel.  Second, it developed a suitable model to represent the flow in question.  Such models are used to follow the flow of fluid in chemical reactors and other process units, like in rivers and streams, or solid and porous structures.  In medicine, the tracer method is used to study the flow of chemicals—harmful  and harmless—in the...

Commercial applications of perfluorocarbon tracer (PFT) technology

International Nuclear Information System (INIS)

Dietz, R.N.

1991-06-01

Tracer technology can be successfully applied to many leak-checking and monitoring evaluations of operating systems (e.g., building HVACs), manufacturing processes and products (e.g., air conditioners), and subsurface components and systems (e.g., underground storage tanks). Perfluorocarbon tracer (PFT) technology is the most sensitive of all tracer technologies because the ambient background levels of the five (5) routinely-used PFTs are in the range of parts per 10 15 parts of air (i.e., parts per quadrillion-ppq) and this technology's instrumentation can measure down to those levels. The effectiveness of this technology is achieved both in terms of cost (very little PFT need to be used) and detectability; for example, very small leaks can be rapidly detected. The PFT compounds, which are environmentally and biologically safe to use, are commercially available as are the sampling and analysis instrumentation. This presentation concerns (1) the steps being taken to commercialize this technology, (2) new applications of processes currently under study, and (3) applications in areas of use that will be particularly beneficial to the environment. 21 refs., 2 figs., 2 tabs

Erbium hydride decomposition kinetics.

Energy Technology Data Exchange (ETDEWEB)

Ferrizz, Robert Matthew

2006-11-01

Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

Triggering radiation alarm at security checks. Patients should be informed even after diagnostic nuclear medicine procedures.

Science.gov (United States)

Palumbo, Barbara; Neumann, Irmgard; Havlik, Ernst; Palumbo, Renato; Sinzinger, Helmut

2009-01-01

During the last few years an increasing number of nuclear medicine patients in various countries evoked a radiation alarm after therapeutic or diagnostic procedures, and even after passive exposure. A prospective calculation of activity retention in the patient's body is difficult due to extremely high variation of uptake and kinetics. Furthermore, different sensitivities and distances of the detectors make a prospective calculation even more difficult. In this article a number of cases are being reported, related problems are discussed and the surprisingly very limited literature reviewed. In order to minimize problems after eventually triggering alarms, we strongly recommend that each patient receives a certificate providing personal data, tracer, dose, half-life of the radionuclide, type and date of procedure applied as well as the nuclear medicine unit to contact for further information. Furthermore, a closer cooperation and exchange of information between the authorities and local nuclear medicine societies, would be welcome.

Quantitative analysis of myocardial kinetics of 15-p-[iodine-125] iodophenylpentadecanoic acid

International Nuclear Information System (INIS)

DeGrado, T.R.; Holden, J.E.; Ng, C.K.; Raffel, D.M.; Gatley, S.J.

1989-01-01

Myocardial extraction and the characteristic tissue clearance of radioactivity following bolus injections of a radioiodinated ( 125 I) long chain fatty acid (LCFA) analog 15-p-iodophenylpentadecanoic acid (IPPA) were examined in the isolated perfused working rat heart. Radioactivity remaining in the heart was monitored with external scintillation probes. A compartmental model which included nonesterified tracer, catabolite, and complex lipid compartments successfully fitted tissue time-radioactivity residue curves, and gave a value for the rate of IPPA oxidation 1.8 times that obtained from steady-state release of tritiated water from labeled palmitic acid. The technique was sensitive to the impairment of LCFA oxidation in hearts of animals treated with the carnitine palmitoyltransferase I inhibitor, 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). IPPA or similar modified fatty acids may be better than 11 C-labeled physiological fatty acids such as palmitate in this type of study, because efflux of unoxidized tracer and catabolite(s) from the heart are kinetically more distinct, and their contributions to the early data can be reliably separated. This technique may be suitable for extension to in vivo measurements with position tomography and appropriate modified fatty acids

Quantitative analysis of myocardial kinetics of 15-p-(iodine-125) iodophenylpentadecanoic acid

Energy Technology Data Exchange (ETDEWEB)

DeGrado, T.R.; Holden, J.E.; Ng, C.K.; Raffel, D.M.; Gatley, S.J.

1989-07-01

Myocardial extraction and the characteristic tissue clearance of radioactivity following bolus injections of a radioiodinated (/sup 125/I) long chain fatty acid (LCFA) analog 15-p-iodophenylpentadecanoic acid (IPPA) were examined in the isolated perfused working rat heart. Radioactivity remaining in the heart was monitored with external scintillation probes. A compartmental model which included nonesterified tracer, catabolite, and complex lipid compartments successfully fitted tissue time-radioactivity residue curves, and gave a value for the rate of IPPA oxidation 1.8 times that obtained from steady-state release of tritiated water from labeled palmitic acid. The technique was sensitive to the impairment of LCFA oxidation in hearts of animals treated with the carnitine palmitoyltransferase I inhibitor, 2(5(4-chlorophenyl)pentyl)oxirane-2-carboxylate (POCA). IPPA or similar modified fatty acids may be better than /sup 11/C-labeled physiological fatty acids such as palmitate in this type of study, because efflux of unoxidized tracer and catabolite(s) from the heart are kinetically more distinct, and their contributions to the early data can be reliably separated. This technique may be suitable for extension to in vivo measurements with position tomography and appropriate modified fatty acids.

Quantitative analysis of myocardial kinetics of 15-p-[iodine-125] iodophenylpentadecanoic acid.

Science.gov (United States)

DeGrado, T R; Holden, J E; Ng, C K; Raffel, D M; Gatley, S J

1989-07-01

Myocardial extraction and the characteristic tissue clearance of radioactivity following bolus injections of a radioiodinated (125I) long chain fatty acid (LCFA) analog 15-p-iodophenylpentadecanoic acid (IPPA) were examined in the isolated perfused working rat heart. Radioactivity remaining in the heart was monitored with external scintillation probes. A compartmental model which included nonesterified tracer, catabolite, and complex lipid compartments successfully fitted tissue time-radioactivity residue curves, and gave a value for the rate of IPPA oxidation 1.8 times that obtained from steady-state release of tritiated water from labeled palmitic acid. The technique was sensitive to the impairment of LCFA oxidation in hearts of animals treated with the carnitine palmitoyltransferase I inhibitor, 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). IPPA or similar modified fatty acids may be better than 11C-labeled physiological fatty acids such as palmitate in this type of study, because efflux of unoxidized tracer and catabolite(s) from the heart are kinetically more distinct, and their contributions to the early data can be reliably separated. This technique may be suitable for extension to in vivo measurements with position tomography and appropriate modified fatty acids.

Liver kinetics of glucose analogs measured in pigs by PET: importance of dual-input blood sampling

DEFF Research Database (Denmark)

Munk, O L; Bass, L; Roelsgaard, K

2001-01-01

-input functions were very similar. CONCLUSION: Compartmental analysis of MG and FDG kinetics using dynamic PET data requires measurements of dual-input activity concentrations. Using the dual-input function, physiologically reasonable parameter estimates of K1, k2, and Vp were obtained, whereas the use......Metabolic processes studied by PET are quantified traditionally using compartmental models, which relate the time course of the tracer concentration in tissue to that in arterial blood. For liver studies, the use of arterial input may, however, cause systematic errors to the estimated kinetic...... parameters, because of ignorance of the dual blood supply from the hepatic artery and the portal vein to the liver. METHODS: Six pigs underwent PET after [15O]carbon monoxide inhalation, 3-O-[11C]methylglucose (MG) injection, and [18F]FDG injection. For the glucose scans, PET data were acquired for 90 min...

Relative distance between tracers as a measure of diffusivity within moving aggregates

Science.gov (United States)

Pönisch, Wolfram; Zaburdaev, Vasily

2018-02-01

Tracking of particles, be it a passive tracer or an actively moving bacterium in the growing bacterial colony, is a powerful technique to probe the physical properties of the environment of the particles. One of the most common measures of particle motion driven by fluctuations and random forces is its diffusivity, which is routinely obtained by measuring the mean squared displacement of the particles. However, often the tracer particles may be moving in a domain or an aggregate which itself experiences some regular or random motion and thus masks the diffusivity of tracers. Here we provide a method for assessing the diffusivity of tracer particles within mobile aggregates by measuring the so-called mean squared relative distance (MSRD) between two tracers. We provide analytical expressions for both the ensemble and time averaged MSRD allowing for direct identification of diffusivities from experimental data.

Complex functionality with minimal computation: Promise and pitfalls of reduced-tracer ocean biogeochemistry models

Science.gov (United States)

Galbraith, Eric D.; Dunne, John P.; Gnanadesikan, Anand; Slater, Richard D.; Sarmiento, Jorge L.; Dufour, Carolina O.; de Souza, Gregory F.; Bianchi, Daniele; Claret, Mariona; Rodgers, Keith B.; Marvasti, Seyedehsafoura Sedigh

2015-12-01

Earth System Models increasingly include ocean biogeochemistry models in order to predict changes in ocean carbon storage, hypoxia, and biological productivity under climate change. However, state-of-the-art ocean biogeochemical models include many advected tracers, that significantly increase the computational resources required, forcing a trade-off with spatial resolution. Here, we compare a state-of-the art model with 30 prognostic tracers (TOPAZ) with two reduced-tracer models, one with 6 tracers (BLING), and the other with 3 tracers (miniBLING). The reduced-tracer models employ parameterized, implicit biological functions, which nonetheless capture many of the most important processes resolved by TOPAZ. All three are embedded in the same coupled climate model. Despite the large difference in tracer number, the absence of tracers for living organic matter is shown to have a minimal impact on the transport of nutrient elements, and the three models produce similar mean annual preindustrial distributions of macronutrients, oxygen, and carbon. Significant differences do exist among the models, in particular the seasonal cycle of biomass and export production, but it does not appear that these are necessary consequences of the reduced tracer number. With increasing CO2, changes in dissolved oxygen and anthropogenic carbon uptake are very similar across the different models. Thus, while the reduced-tracer models do not explicitly resolve the diversity and internal dynamics of marine ecosystems, we demonstrate that such models are applicable to a broad suite of major biogeochemical concerns, including anthropogenic change. These results are very promising for the further development and application of reduced-tracer biogeochemical models that incorporate "sub-ecosystem-scale" parameterizations.

Use of indium and rare-earths activable tracers for the evaluation of the hydraulic performance of wastewater treatment units

International Nuclear Information System (INIS)

Alvarenga, Gilmara Lucia Souza; Barreto, Alberto Avelar; Pinto, Amenonia Maria Ferreira; Moreira, Rubens Martins; Silva, Lauris Lucia da

2013-01-01

Efforts aimed at going deeper into the understanding of the purification processes of contaminated waters and at the optimization of both the technological and economic performance of such processes have been developed following the introduction of innovative wastewater treatment processes. Among the several wastewater depuration processes, this study focuses physical aspects of systems known as artificial wetlands and a special version of the anaerobic biological reactor. This biological reactor is of the upflow anaerobic sludge blanket (UASB) type, which is increasingly being utilized for the processing of urban wastewater. However, its effluent eventually needs some polishing to be performed at an artificial wetland stage. The hydrodynamic performances of both a special version of the UASB and a vegetated wetland have been studied using the tracer methodology, based on the impulse response of these systems. Both radioactive and activable tracers have been employed and had their information analyzed by appropriate software. Comments are presented on the advantages of the activable tracers. The results thus obtained have demonstrated the potential of the application of activable tracers in the experimental research of either natural or artificial hydraulic systems. (author)

Use of indium and rare-earths activable tracers for the evaluation of the hydraulic performance of wastewater treatment units

Energy Technology Data Exchange (ETDEWEB)

Alvarenga, Gilmara Lucia Souza; Barreto, Alberto Avelar; Pinto, Amenonia Maria Ferreira; Moreira, Rubens Martins, E-mail: gil_lsa@yahoo.com.br, E-mail: aab@cdtn.br, E-mail: amfp@cdtn.br, E-mail: rubens@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Silva, Lauris Lucia da, E-mail: laurislsilva@yahoo.com.br [Universidade Federal de Minas Gerais (DQ/UFMG), Minas Gerais, MG (Brazil). Dept. de Quimica

2013-07-01

Efforts aimed at going deeper into the understanding of the purification processes of contaminated waters and at the optimization of both the technological and economic performance of such processes have been developed following the introduction of innovative wastewater treatment processes. Among the several wastewater depuration processes, this study focuses physical aspects of systems known as artificial wetlands and a special version of the anaerobic biological reactor. This biological reactor is of the upflow anaerobic sludge blanket (UASB) type, which is increasingly being utilized for the processing of urban wastewater. However, its effluent eventually needs some polishing to be performed at an artificial wetland stage. The hydrodynamic performances of both a special version of the UASB and a vegetated wetland have been studied using the tracer methodology, based on the impulse response of these systems. Both radioactive and activable tracers have been employed and had their information analyzed by appropriate software. Comments are presented on the advantages of the activable tracers. The results thus obtained have demonstrated the potential of the application of activable tracers in the experimental research of either natural or artificial hydraulic systems. (author)

Inverse modelling of atmospheric tracers: non-Gaussian methods and second-order sensitivity analysis

Directory of Open Access Journals (Sweden)

M. Bocquet

2008-02-01

Full Text Available For a start, recent techniques devoted to the reconstruction of sources of an atmospheric tracer at continental scale are introduced. A first method is based on the principle of maximum entropy on the mean and is briefly reviewed here. A second approach, which has not been applied in this field yet, is based on an exact Bayesian approach, through a maximum a posteriori estimator. The methods share common grounds, and both perform equally well in practice. When specific prior hypotheses on the sources are taken into account such as positivity, or boundedness, both methods lead to purposefully devised cost-functions. These cost-functions are not necessarily quadratic because the underlying assumptions are not Gaussian. As a consequence, several mathematical tools developed in data assimilation on the basis of quadratic cost-functions in order to establish a posteriori analysis, need to be extended to this non-Gaussian framework. Concomitantly, the second-order sensitivity analysis needs to be adapted, as well as the computations of the averaging kernels of the source and the errors obtained in the reconstruction. All of these developments are applied to a real case of tracer dispersion: the European Tracer Experiment [ETEX]. Comparisons are made between a least squares cost function (similar to the so-called 4D-Var approach and a cost-function which is not based on Gaussian hypotheses. Besides, the information content of the observations which is used in the reconstruction is computed and studied on the application case. A connection with the degrees of freedom for signal is also established. As a by-product of these methodological developments, conclusions are drawn on the information content of the ETEX dataset as seen from the inverse modelling point of view.

SIMULASI JARINGAN KOMPUTER MENGGUNAKAN CISCO PACKET TRACER

Directory of Open Access Journals (Sweden)

M Mufadhol

2012-01-01

Full Text Available Perkembangan jaringan komputer saat ini begitu pesat, monitoring jaringan komputer akan menjadi suatu hal yang sulit dan rumit. Koneksi jaringan komputer merupakan suatu hal yang mendasar dalam suatu jaringan, karena bila koneksi itu bermasalah maka semua jenis aplikasi yang dijalankan melalui jaringan komputer tidak dapat digunakan. Cisco packet tracer dapat digunakan untuk simulasi yang mencerminkan arsitektur dan juga model dari jaringan komputer pada sistem jaringan yang digunakan. Dengan menggunakan aplikasi cisco packet tracer, simulasi mengenai jaringan dapat dimanfaatkan menjadi informasi tentang keadaan koneksi komputer dalam suatu jaringan.

15N Kinetic Analysis of N2O Production by Nitrosomonas europaea: an Examination of Nitrifier Denitrification

OpenAIRE

Poth, Mark; Focht, Dennis D.

1985-01-01

A series of 15N isotope tracer experiments showed that Nitrosomonas europaea produces nitrous oxide only under oxygen-limiting conditions and that the labeled N from nitrite, but not nitrate, is incorporated into nitrous oxide, indicating the presence of the “denitrifying enzyme” nitrite reductase. A kinetic analysis of the m/z 44, 45, and 46 nitrous oxide produced by washed cell suspensions of N. europaea when incubated with 4 mM ammonium (99% 14N) and 0.4 mM nitrite (99% 15N) was performed....

Nuclear reactor kinetics and plant control

CERN Document Server

Oka, Yoshiaki

2013-01-01

Understanding time-dependent behaviors of nuclear reactors and the methods of their control is essential to the operation and safety of nuclear power plants. This book provides graduate students, researchers, and engineers in nuclear engineering comprehensive information on both the fundamental theory of nuclear reactor kinetics and control and the state-of-the-art practice in actual plants, as well as the idea of how to bridge the two. The first part focuses on understanding fundamental nuclear kinetics. It introduces delayed neutrons, fission chain reactions, point kinetics theory, reactivit

Development and application of a modified wireless tracer for disaster prevention

Science.gov (United States)

Chung Yang, Han; Su, Chih Chiang

2016-04-01

Typhoon-induced flooding causes water overflow in a river channel, which results in general and bridge scour and soil erosion, thus leading to bridge failure, debris flow and landslide collapse. Therefore, dynamic measurement technology should be developed to assess scour in channels and landslide as a disaster-prevention measure against bridge failure and debris flow. This paper presents a wireless tracer that enables monitoring general scour in river channels and soil erosion in hillsides. The wireless tracer comprises a wireless high-power radio modem, various electronic components, and a self-designed printed circuit board that are all combined with a 9-V battery pack and an auto switch. The entire device is sealed in a jar by silicon. After it was modified, the wireless tracer underwent the following tests for practical applications: power continuation and durability, water penetration, and signal transmission during floating. A regression correlation between the wireless tracer's transmission signal and distance was also established. This device can be embedded at any location where scouring is monitored, and, in contrast to its counterparts that detect scour depth by identifying and analyzing received signals, it enables real-time observation of the scouring process. In summary, the wireless tracer developed in this study provides a dynamic technology for real-time monitoring of scouring (or erosion) and forecasting of landslide hazards. Keywords: wireless tracer; scour; real-time monitoring; landslide hazard.

Mechanical, electronic and instrumentation development for tracer tests at El Berrocal site

International Nuclear Information System (INIS)

Gutierrez, M.G.; Benitez, A.H.; Yllera de Llano, A.; Romero, P.R.; Aleixandre, J.; Bueno, J.; Gonzalez, O.; Tamarit, J.; Guimera, J.

1997-01-01

The international El Berrocal Project was an integrated exercise in geological, geochemical and hydrogeological characterization with the aim of understanding and modelling the past and present-day migration processes that control the behaviour and distribution of naturally occurring radionuclides in a fractured granitic environment. Information is presented concerning the design and manufacture of the instrumentation used for the large scale tracer tests performed at El Berrocal, and the instrumentation and data acquisition development is specified. (author)

The importance of inclusion of kinetic information in the extrapolation of high-to-low concentrations for human limit setting.

Science.gov (United States)

Geraets, Liesbeth; Zeilmaker, Marco J; Bos, Peter M J

2018-01-05

Human health risk assessment of inhalation exposures generally includes a high-to-low concentration extrapolation. Although this is a common step in human risk assessment, it introduces various uncertainties. One of these uncertainties is related to the toxicokinetics. Many kinetic processes such as absorption, metabolism or excretion can be subject to saturation at high concentration levels. In the presence of saturable kinetic processes of the parent compound or metabolites, disproportionate increases in internal blood or tissue concentration relative to the external concentration administered may occur resulting in nonlinear kinetics. The present paper critically reviews human health risk assessment of inhalation exposure. More specific, it emphasizes the importance of kinetic information for the determination of a safe exposure in human risk assessment of inhalation exposures assessed by conversion from a high animal exposure to a low exposure in humans. For two selected chemicals, i.e. methyl tert-butyl ether and 1,2-dichloroethane, PBTK-modelling was used, for illustrative purposes, to follow the extrapolation and conversion steps as performed in existing risk assessments for these chemicals. Human health-based limit values based on an external dose metric without sufficient knowledge on kinetics might be too high to be sufficiently protective. Insight in the actual internal exposure, the toxic agent, the appropriate dose metric, and whether an effect is related to internal concentration or dose is important. Without this, application of assessment factors on an external dose metric and the conversion to continuous exposure results in an uncertain human health risk assessment of inhalation exposures. Copyright © 2017 Elsevier B.V. All rights reserved.

Methane emission quantification from landfills using a double tracer approach

DEFF Research Database (Denmark)

Scheutz, Charlotte; Samuelsson, J.; Fredenslund, Anders Michael

2007-01-01

A tracer method was successfully used for quantification of the whole methane (CH4) emission from Fakse landfill. By using two different tracers the emission from different sections of the landfill could be quantified. Furthermore, is was possible to determine the emissions from local on site...

Tracer simulation using a global general circulation model: Results from a midlatitude instantaneous source experiment

International Nuclear Information System (INIS)

Mahlman, J.D.; Moxim, W.J.

1978-01-01

An 11-level general circulation model with seasonal variation is used to perform an experiment on the dispersion of passive tracers. Specially constructed time-dependent winds from this model are used as input to a separate tracer model. The methodologies employed to construct the tracer model are described.The experiment presented is the evolution of a hypothetical instantaneous source of tracer on 1 Janaury with maximum initial concentration at 65 mb, 36 0 N, 180 0 E. The tracer is assumed to have no sources or sinks in the stratosphere, but is subject to removal processes in the lower troposphere.The experimental results reveal a number of similarities to observed tracer behavior, including the average poleward-downward slope of mixing ratio isopleths, strong tracer gradients across the tropopause, intrusion of tracer into the Southern Hemisphere lower stratosphere, and the long-term interhemispheric exchange rate. The model residence times show behavior intermediate to those exhibited for particulate radioactive debris and gaseous C 14 O 2 . This suggests that caution should be employed when either radioactive debris or C 14 O 2 data are used to develop empirical models for prediction of gaseous tracers which are efficiently removed in the troposphere.In this experiment, the tracer mixing ratio and potential vorticity evolve to very high correlations. Mechanisms for this correlation are discussed. The zonal mean tracer balances exhibit complex behavior among the various transport terms. At early stages, the tracer evolution is dominated by eddy effects. Later, a very large degree of self-cancellation between mean cell and eddy effects is observed. During seasonal transitions, however, this self-cancellation diminishes markedly, leading to significant changes in the zonal mean tracer distribution. A possible theoretical explanation is presented

An experimental study of tracers for labelling of injection gas in oil reservoirs

International Nuclear Information System (INIS)

Dugstad, Oe.

1992-01-01

This work demonstrates the feasibility of the PMCP and PMCH as tracers in field experiments. These compounds have properties which make them as well suited for well to well studies as the more common tracers CH 3 T and 85 Kr. In an injection project carried out at the Gullfaks field in the North Sea the two PFCs verified communication between wells. This implies communication between different geological layers in the reservoir and also communication across faults within the same layers. Laboratory studies carried out have focused on the retention of the tracers in dynamic flooding experiments under conditions comparable with those in the petroleum reservoirs. Simultaneous injection of a variety of tracers has shown individual variations in tracer retention which are caused by important reservoir parameters as fluid saturation and rock properties. By proper design of field injection programs the tracers response may therefore be used to estimate fluid saturation if actual rock properties are known. 45 refs., 20 figs., 13 tabs

Ambiguity in measuring matrix diffusion with single-well injection/recovery tracer tests

Science.gov (United States)

Lessoff, S.C.; Konikow, Leonard F.

1997-01-01

Single-well injection/recovery tracer tests are considered for use in characterizing and quantifying matrix diffusion in dual-porosity aquifers. Numerical modeling indicates that neither regional drift in homogeneous aquifers, nor heterogeneity in aquifers having no regional drift, nor hydrodynamic dispersion significantly affects these tests. However, when drift is coupled simultaneously with heterogeneity, they can have significant confounding effects on tracer return. This synergistic effect of drift and heterogeneity may help explain irreversible flow and inconsistent results sometimes encountered in previous single-well injection/recovery tracer tests. Numerical results indicate that in a hypothetical single-well injection/recovery tracer test designed to demonstrate and measure dual-porosity characteristics in a fractured dolomite, the simultaneous effects of drift and heterogeneity sometimes yields responses similar to those anticipated in a homogeneous dual-porosity formation. In these cases, tracer recovery could provide a false indication of the occurrence of matrix diffusion. Shortening the shut-in period between injection and recovery periods may make the test less sensitive to drift. Using multiple tracers having different diffusion characteristics, multiple tests having different pumping schedules, and testing the formation at more than one location would decrease the ambiguity in the interpretation of test data.

The use of radioactive and other tracers in oil and gas measurement

International Nuclear Information System (INIS)

Edmonds, E.A.

1985-01-01

A description and critical discussion of the use of tracer techniques of flowrate measurement in the oil and gas industries. Radioactive tracers are discussed in particular, with emphasis on the practical aspects of their use. Radiotracers suitable for use in industrial environments are described and discussed. The advantages of radiotracers over conventional chemical tracers are reviewed and the logistical problems associated with the use of radioactive materials are considered. The results of measurements conducted using radiotracers on operating plant and on calibration facilities are presented with a discussion of the accuracy of measurement of flowrate which is achievable: potentially, in ideal circumstances, and in practical situations. The modification of tracer techniques of flow measurement to enable residence time distributions to be evaluated and leaks to be located and quantified on operating process plant is illustrated and discussed. The use of specially synthesized radiochemicals for tracing complex petrochemical processes involving chemical reactions and multiproduct streams is described. The use of novel non-radioactive tracers and specialized detection systems is also described, again with practical illustrations of experience in the field. The benefits offered by the use of these tracers and the limitations encountered are discussed. (author)

Tracer SWIW tests in propped and un-propped fractures: parameter sensitivity issues, revisited

Science.gov (United States)

Ghergut, Julia; Behrens, Horst; Sauter, Martin

2017-04-01

Single-well injection-withdrawal (SWIW) or 'push-then-pull' tracer methods appear attractive for a number of reasons: less uncertainty on design and dimensioning, and lower tracer quantities required than for inter-well tests; stronger tracer signals, enabling easier and cheaper metering, and shorter metering duration required, reaching higher tracer mass recovery than in inter-well tests; last not least: no need for a second well. However, SWIW tracer signal inversion faces a major issue: the 'push-then-pull' design weakens the correlation between tracer residence times and georeservoir transport parameters, inducing insensitivity or ambiguity of tracer signal inversion w. r. to some of those georeservoir parameters that are supposed to be the target of tracer tests par excellence: pore velocity, transport-effective porosity, fracture or fissure aperture and spacing or density (where applicable), fluid/solid or fluid/fluid phase interface density. Hydraulic methods cannot measure the transport-effective values of such parameters, because pressure signals correlate neither with fluid motion, nor with material fluxes through (fluid-rock, or fluid-fluid) phase interfaces. The notorious ambiguity impeding parameter inversion from SWIW test signals has nourished several 'modeling attitudes': (i) regard dispersion as the key process encompassing whatever superposition of underlying transport phenomena, and seek a statistical description of flow-path collectives enabling to characterize dispersion independently of any other transport parameter, as proposed by Gouze et al. (2008), with Hansen et al. (2016) offering a comprehensive analysis of the various ways dispersion model assumptions interfere with parameter inversion from SWIW tests; (ii) regard diffusion as the key process, and seek for a large-time, asymptotically advection-independent regime in the measured tracer signals (Haggerty et al. 2001), enabling a dispersion-independent characterization of multiple

Deciphering relationships between in-stream travel times, nutrient concentrations, and uptake through analysis of hysteretic and non-hysteretic kinetic behavior

Science.gov (United States)

Covino, T. P.; Bowden, W. B.; Gooseff, M. N.; Wollheim, W. M.; McGlynn, B. L.; Whittinghill, K. A.; Wlostowski, A. N.; Herstand, M. R.

2012-12-01

Understanding the relationship between solute travel time, concentration, and nutrient uptake remains a central question in watershed hydrology and biogeochemistry. Theoretical understanding predicts that nutrient uptake should increase as in-stream solute travel time lengthens and/or as concentration increases; however, results from field-based studies have been contradictory. We used a newly developed approach, Tracer Additions for Spiraling Curve Characterization (TASCC), to investigate relationships between solute travel time, nutrient concentration, and nutrient uptake across a range of stream types. This approach allows us to quantify in-stream nutrient uptake across a range of travel times and nutrient concentrations using single instantaneous injections (slugs) of conservative and non-conservative tracers. In some systems we observed counter-clockwise hysteresis loops in the relationship between nutrient uptake and concentration. Greater nutrient uptake on the falling limb of tracer breakthrough curves indicates stronger uptake for a given concentration at longer travel times. However, in other systems we did not observe hysteresis in these relationships. Lack of hysteresis indicates that nutrient uptake kinetics were not influenced by travel time travel time. Here we investigate the potential roles of travel time and in-stream flowpaths that could be responsible for hysteretic behavior.

Results of repeat tracer tests at Ohaaki, NZ

International Nuclear Information System (INIS)

McCabe, W.J.; Morris, C.

1995-01-01

During 20 years of tracer testing at Ohaaki a number of wells have been used more than once as tracer injection sites. In studying the various responses obtained it has been necessary to consider variations in the experimental test conditions before making comparisons which relate to field conditions. Some very significant changes have occurred in the field hydrology in recent years and water flow speeds as high as those encountered at Wairakei have been demonstrated. (author). 4 refs., 2 tabs., 10 figs

Experiments to Evaluate and Implement Passive Tracer Gas Methods to Measure Ventilation Rates in Homes

Energy Technology Data Exchange (ETDEWEB)

Lunden, Melissa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Heredia, Elizabeth [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cohn, Sebastian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Noris, Federico [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Logue, Jennifer [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hotchi, Toshifumi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-10-01

This report documents experiments performed in three homes to assess the methodology used to determine air exchange rates using passive tracer techniques. The experiments used four different tracer gases emitted simultaneously but implemented with different spatial coverage in the home. Two different tracer gas sampling methods were used. The results characterize the factors of the execution and analysis of the passive tracer technique that affect the uncertainty in the calculated air exchange rates. These factors include uncertainties in tracer gas emission rates, differences in measured concentrations for different tracer gases, temporal and spatial variability of the concentrations, the comparison between different gas sampling methods, and the effect of different ventilation conditions.

Visual evaluation of kinetic characteristics of PET probe for neuroreceptors using a two-phase graphic plot analysis.

Science.gov (United States)

Ito, Hiroshi; Ikoma, Yoko; Seki, Chie; Kimura, Yasuyuki; Kawaguchi, Hiroshi; Takuwa, Hiroyuki; Ichise, Masanori; Suhara, Tetsuya; Kanno, Iwao

2017-05-01

Objectives In PET studies for neuroreceptors, tracer kinetics are described by the two-tissue compartment model (2-TCM), and binding parameters, including the total distribution volume (V T ), non-displaceable distribution volume (V ND ), and binding potential (BP ND ), can be determined from model parameters estimated by kinetic analysis. The stability of binding parameter estimates depends on the kinetic characteristics of radioligands. To describe these kinetic characteristics, we previously developed a two-phase graphic plot analysis in which V ND and V T can be estimated from the x-intercept of regression lines for early and delayed phases, respectively. In this study, we applied this graphic plot analysis to visual evaluation of the kinetic characteristics of radioligands for neuroreceptors, and investigated a relationship between the shape of these graphic plots and the stability of binding parameters estimated by the kinetic analysis with 2-TCM in simulated brain tissue time-activity curves (TACs) with various binding parameters. Methods 90-min TACs were generated with the arterial input function and assumed kinetic parameters according to 2-TCM. Graphic plot analysis was applied to these simulated TACs, and the curvature of the plot for each TAC was evaluated visually. TACs with several noise levels were also generated with various kinetic parameters, and the bias and variation of binding parameters estimated by kinetic analysis were calculated in each TAC. These bias and variation were compared with the shape of graphic plots. Results The graphic plots showed larger curvature for TACs with higher specific binding and slower dissociation of specific binding. The quartile deviations of V ND and BP ND determined by kinetic analysis were smaller for radioligands with slow dissociation. Conclusions The larger curvature of graphic plots for radioligands with slow dissociation might indicate a stable determination of V ND and BP ND by kinetic analysis. For

Considerations on the assessment of economic benefits of industrial tracer application

International Nuclear Information System (INIS)

Guizerix, J.; Margrita, R.

1990-01-01

The benefit of a particular tracer study which can always theoretically be derived is practically very difficult to assess for decision-making which is more often based on rough estimates of it. Other criteria, as safety, environmental protection, 'social benefit', may replace the purely economic considerations. The economic benefits of industrial tracer applications can clearly be perceived through the commercial success of businesses offering tracer services, which implies that all factors involved in the law of supply and demand have (tacitly or explictly) been accounted. (orig.) [de

Application of artificial radioactive tracers for groundwater flow

International Nuclear Information System (INIS)

Hamza, M.S.; Aly, A.I.M.; Swailem, F.M.; Nada, A.A.; Awad, M.A.

1989-01-01

In this work, the groundwater velocity was estimated by applying radioactive tracer techniques: the single well and the multiple well methods. In the first single well method, radioactive iodine-131 was injected in the well and the radioactivity was monitored with time. The groundwater flow was estimated as a function of the concentration dilution factor of the tracer taking into consideration the permeability of the filter screen and the aquifer. The second method (the multiple well technique) is based on direct measuring of the period of time the tracer needs to disperse from the injection well to one of receptor well arranged in a circle around the injection. The latter method was found to be more accurate and reliable and has also the advantage of determining the groundwater velocity and direction of flow as well. The limitations of the single well technique are discussed and a detailed comparison between single and multi-well techniques is given

Tritium as tracer of flow in constructed wetlands

International Nuclear Information System (INIS)

Wachniew, P.; Czuprynski, P.; Maloszewski, P.

2005-01-01

Constructed wetlands technology is a cost-effective and environmentally friendly method used world-wide to treat waste waters of different origins. The soluble pollutants are transformed and removed mainly through the processes that occur at surfaces of plants, plant debris or filtering media. The efficiency of soluble pollutants removal is thus primarily related to the extent of contact between waste waters and the reactive surfaces. Residence time distributions function (RTD)is basic characteristic of wetland hydraulic properties and can be obtained by combined use of tracer technique and mathematical modelling. Tritium was used as to obtain RTD's of three parallel cells of a sub-surface flow constructed wetland overgrown with Pharagmites australis in Nowa Slupia. Tritium as a part of water molecule, is an ideal tracer of flow in the highly reactive environment of constructed wetlands. Results of the tracer test interpreted by the assumed model (Multi Flow Dispersion Model) of conservative solute transport revealed a complex structure of flow through the wetland. (author)

Synthesis of tracers using automated radiochemistry and robotics

International Nuclear Information System (INIS)

Dannals, R.F.

1992-07-01

Synthesis of high specific activity radiotracers labeled with short-lived positron-emitting radionuclides for positron emission tomography (PET) often requires handling large initial quantities of radioactivity. High specific activities are required when preparing tracers for use in PET studies of neuroreceptors. A fully automated approach for tracer synthesis is highly desirable. This proposal involves the development of a system for the Synthesis of Tracers using Automated Radiochemistry and Robotics (STARR) for this purpose. While the long range objective of the proposed research is the development of a totally automated radiochemistry system for the production of major high specific activity 11 C-radiotracers for use in PET, the specific short range objectives are the automation of 11 C-methyl iodide ( 11 CH 3 I) production via an integrated approach using both radiochemistry modular labstations and robotics, and the extension of this automated capability to the production of several radiotracers for PET (initially, 11 C-methionine, 3-N-[ 11 C-methyl]spiperone, and [ 11 C]-carfentanil)

Contamination Tracer Testing With Seabed Rock Drills: IODP Expedition 357

Science.gov (United States)

Orcutt, B.; Bergenthal, M.; Freudenthal, T.; Smith, D. J.; Lilley, M. D.; Schneiders, L.; Fruh-Green, G. L.

2016-12-01

IODP Expedition 357 utilized seabed rock drills for the first time in the history of the ocean drilling program, with the aim of collecting intact core of shallow mantle sequences from the Atlantis Massif to examine serpentinization processes and the deep biosphere. This new drilling approach required the development of a new system for delivering synthetic tracers during drilling to assess for possible sample contamination. Here, we describe this new tracer delivery system, assess the performance of the system during the expedition, provide an overview of the quality of the core samples collected for deep biosphere investigations based on tracer concentrations, and make recommendations for future applications of the system.

Multi-tracer investigation of river and groundwater interactions: a case study in Nalenggele River basin, northwest China

Science.gov (United States)

Xu, Wei; Su, Xiaosi; Dai, Zhenxue; Yang, Fengtian; Zhu, Pucheng; Huang, Yong

2017-11-01

Environmental tracers (such as major ions, stable and radiogenic isotopes, and heat) monitored in natural waters provide valuable information for understanding the processes of river-groundwater interactions in arid areas. An integrated framework is presented for interpreting multi-tracer data (major ions, stable isotopes (2H, 18O), the radioactive isotope 222Rn, and heat) for delineating the river-groundwater interactions in Nalenggele River basin, northwest China. Qualitative and quantitative analyses were undertaken to estimate the bidirectional water exchange associated with small-scale interactions between groundwater and surface water. Along the river stretch, groundwater and river water exchange readily. From the high mountain zone to the alluvial fan, groundwater discharge to the river is detected by tracer methods and end-member mixing models, but the river has also been identified as a losing river using discharge measurements, i.e. discharge is bidirectional. On the delta-front of the alluvial fan and in the alluvial plain, in the downstream area, the characteristics of total dissolved solids values, 222Rn concentrations and δ18O values in the surface water, and patterns derived from a heat-tracing method, indicate that groundwater discharges into the river. With the environmental tracers, the processes of river-groundwater interaction have been identified in detail for better understanding of overall hydrogeological processes and of the impacts on water allocation policies.

Novel tracer for radiation treatment planning

International Nuclear Information System (INIS)

Schwarzenboeck, S.; Krause, B.J.; Herrmann, K.; Gaertner, F.; Souvatzoglou, M.; Klaesner, B.

2011-01-01

PET and PET/CT with innovative tracers gain increasing importance in diagnosis and therapy management, and radiation treatment planning in radio-oncology besides the widely established FDG. The introduction of [ 18 F]Fluorothymidine ([ 18 F]FLT) as marker of proliferation, [ 18 F]Fluoromisonidazole ([ 18 F]FMISO) and [ 18 F]Fluoroazomycin-Arabinoside ([ 18 F]FAZA) as tracer of hypoxia, [ 18 F]Fluoroethyltyrosine ([ 18 F]FET) and [ 11 C]Methionine for brain tumour imaging, [ 68 Ga]DOTATOC for somatostatin receptor imaging, [ 18 F]FDOPA for dopamine synthesis and radioactively labeled choline derivatives for imaging phospholipid metabolism have opened novel approaches to tumour imaging. Some of these tracers have already been implemented into radio-oncology: Amino acid PET and PET/CT have the potential to optimise radiation treatment planning of brain tumours through accurate delineation of tumour tissue from normal tissue, necrosis and edema. Hypoxia represents a major therapeutic problem in radiation therapy. Hypoxia imaging is very attractive as it may allow to increase the dose in hypoxic tumours potentially allowing for a better tumour control. Advances in hybrid imaging, i.e. the introduction of MR/PET, may also have an impact in radio-oncology through synergies related to the combination of molecular signals of PET and a high soft tissue contrast of MRI as well as functional MRI capabilities. (orig.)

Temperature as a tracer of hydrological dynamics in an anchialine cave system with a submarine spring

Science.gov (United States)

Domínguez-Villar, David; Cukrov, Neven; Krklec, Kristina

2018-01-01

Although temperature is a nonconservative tracer, it often provides useful information to understand hydrological processes. This study explores the potential of temperature to characterize the hydrological dynamics of a submarine spring and its coastal karst aquifer in Krka Estuary (Croatia). The estuary is well stratified and its water column has a clear thermocline. A network of loggers was designed to monitor the temperature along vertical profiles in the estuary and the coastal aquifer, taking advantage of an anchialine cave that enabled access to the subterranean estuary. The location of the thermocline in the groundwater, which defines the upper boundary of the saline intrusion, depends on (1) the recharge of the aquifer via infiltration of precipitation, (2) the evolution of the thermocline in the estuary, and (3) the tidal oscillations. The sources of water flowing though the anchialine cave were identified: brackish water from the estuary above the thermocline, saline water from the estuary below the thermocline, and freshwater from infiltrated precipitation. A conceptual model is described that characterizes the hydrological dynamics of this coastal aquifer and its interactions with the estuary. Thus, at least for some hydrological settings, temperature is a valid tracer to characterize the main hydrological processes. The measurement of temperature is inexpensive compared to other (conservative) tracers. Therefore, for those hydrological settings that have water masses with distinct temperatures, the use of temperature as a tracer to establish conceptual models of the hydrological dynamics is encouraged.

New developments in the use of stable activable tracers in environmental science

International Nuclear Information System (INIS)

Loveland, W.; Keasler, K.; Ghannam, L.; Borovik, A.

1980-01-01

Recent developments in the use of stable activable tracers (SATs) in environmental science are reported. (A stable activable tracer is a stable material injected into a system under study and whose concentration is measured by post-sampling activation analysis.) The activable nuclear parts of the tracers studied have been rare earth nuclides with short-lived activation products or Cu. To trace the fate of fluid-bound pollutants (and/or water masses) in marine waters, we have used anionic DTPA complexes of the rare earths. These tracers were shown to be stable (80 to 90% nondissociated) in extensive laboratory tests involving solutions of the tracer in estuarine water including large amounts of marine sediments. Results of a field study in which the flushing time and other hydrological characteristics of an estuarine marina were measured by simultaneously using a fluorescent dye and a SAT are presented. To trace the path of potentially toxic organic molecules, three stable activable tracers, dysprosium(III)-trisacetylacetonate DY(acac) 3 3H 2 O), dysprosium(III)-trisdibenzoylmethane (DY(dbm) 3 H 2 O and copper oxinate Cu (C 9 H 6 ON) 2 were synthesized. Their octanol/water partition coefficients and their solubility in water were measured and used to correlate the tracer species and its biological activity with that of known toxic materials. In a project to demonstrate the simple use of SATs to trace the origin of common insecticides and herbicides, seven common insecticides and herbicides were marked with anionic rare earth DTPA complexes and shown to be detectable at dilutions of 1 part in 10 12 . Two arsenical herbicides were chosen for further study and the tracer/herbicide ratio was shown to remain constant in samples of herbicide material collected on plant surfaces and runoff waters in the environment for long periods

Leak testing of bubble-tight dampers using tracer gas techniques

Energy Technology Data Exchange (ETDEWEB)

Lagus, P.L. [Lagus Applied Technology, Inc., San Diego, CA (United States); DuBois, L.J. [Commonwealth Edison, Zion, IL (United States); Fleming, K.M. [NCS Corporation, Columbus, OH (United States)] [and others

1995-02-01

Recently tracer gas techniques have been applied to the problem of measuring the leakage across an installed bubble-tight damper. A significant advantage of using a tracer gas technique is that quantitative leakage data are obtained under actual operating differential pressure conditions. Another advantage is that leakage data can be obtained using relatively simple test setups that utilize inexpensive materials without the need to tear ducts apart, fabricate expensive blank-off plates, and install test connections. Also, a tracer gas technique can be used to provide an accurate field evaluation of the performance of installed bubble-tight dampers on a periodic basis. Actual leakage flowrates were obtained at Zion Generating Station on four installed bubble-tight dampers using a tracer gas technique. Measured leakage rates ranged from 0.01 CFM to 21 CFM. After adjustment and subsequent retesting, the 21 CFM damper leakage was reduced to a leakage of 3.8 CFM. In light of the current regulatory climate and the interest in Control Room Habitability issues, imprecise estimates of critical air boundary leakage rates--such as through bubble-tight dampers--are not acceptable. These imprecise estimates can skew radioactive dose assessments as well as chemical contaminant exposure calculations. Using a tracer gas technique, the actual leakage rate can be determined. This knowledge eliminates a significant source of uncertainty in both radioactive dose and/or chemical exposure assessments.

Guiding principles for estimation of whole-body synthesis rates by tracer experiments

International Nuclear Information System (INIS)

Krawielitzki, K.; Schadereit, R.; Wuensche, J.

1989-01-01

Methodical recommendations are suggested-predominantly for laboratory and small animals (rats and young chickens)-for the determination of parameters of the protein metabolism of the whole body after single dosis of a mixture of 15 N-labelled amino acids by means of the determination of the temporal course of cumulative 15 N excretion in urine and the assessment of the tracer kinetic data in a compartment model. These recommendations are to make it possible to carry out purposefully such experiments under comparable conditions. The advantages of this method are: (1) the non-invasive character of the method; (2) the possibility of repeating the experiment with the same animal; (3) the adaptability to other methods of investigation (e.g. measuring energy metabolism); (4) the relatively low expenditure of labour and requirement of test animals; (5) the relatively good reproducibility of the method. Thus this method is a good supplement to the flooding and permanent infusion methods and should be used wherever the determination of parameters of the protein metabolism of the total body is sufficient. (author)

Tracer techniques for determination of groundwater flow parameters

International Nuclear Information System (INIS)

Drost, W.; Klotz, D.

1988-05-01

The most common one-borehole and multiple borehole methods using tracers for the direct determination of the groundwater flow parameters (velocity of flow, flow direction) and for the indirect determination of characteristic quantities of the aquifer (effective porosity, dispersivity, transmissivity) are presented methodically and their value is documented by practical examples. Especially, the properties of and measuring technique with suitable tracers are considered (e.g. T, Na-24, Cr-51, Co-58, Co-60, Br-82, Tc-99, I-125, I-131, Au-198). (orig./HP) [de

Development of Input Function Measurement System for Small Animal PET Study

International Nuclear Information System (INIS)

Kim, Jong Guk; Kim, Byung Su; Kim, Jin Su

2010-01-01

For quantitative measurement of radioactivity concentration in tissue and a validated tracer kinetic model, the high sensitive detection system has been required for blood sampling. With the accurate measurement of time activity curves (TACs) of labeled compounds in blood (plasma) enable to provide quantitative information on biological parameters of interest in local tissue. Especially, the development of new tracers for PET imaging requires knowledge of the kinetics of the tracer in the body and in arterial blood and plasma. Conventional approaches of obtaining an input function are to sample arterial blood sequentially by manual as a function of time. Several continuous blood sampling systems have been developed and used in nuclear medicine research field to overcome the limited temporal resolution in sampling by the conventional method. In this work, we developed the high sensitive and unique geometric design of GSO detector for small animal blood activity measurement

Kinetic and mass transfer studies on the isomerization of cellulose hydrolyzate using immobilized Streptomyces cells

Energy Technology Data Exchange (ETDEWEB)

Ghose, T K; Chand, S

1978-01-01

Streptomyces cells possessing glucose isomerase activity, heat-treated and confined within polyester sacs have been used in batch/continuous isomerization of enzymatically hydrolyzed microcrystalline cellulose. Conversion data at different concentrations of substrate closely follow the reactor performance equation based on the reaction kinetics. The effect of external film and pore diffusional resistances were experimentally found to be negligible. The dispersion effects in the packed bed column have been evaluated by pulse input tracer analysis. Continuous operation of the column to isomerize cellulose hydrolyzate (2.0 M glucose) showed an exponential deactivation of enzyme activity with a half-life of 447 h.

Drug-Target Kinetics in Drug Discovery.

Science.gov (United States)

Tonge, Peter J

2018-01-17