Tracer long-term

N. E. V. Rodrigues, B. A. Robinson, and E. Counce, "Tracer Experiment Results During the Long-Term Flow Test of the Fenton Hill Reservoir", Proceedings of the Eighteenth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, Calif., 1994, in press. 

Tc -containing tracers to the body and generate an image, but short enough to minimize long-term... 

You are interested in the hydraulic and geochemical properties of an aquifer, particularly in its dispersivity and average organic matter content. Fortunately, at your disposition you have long-term time series of water temperature and tetrachloroethene (PCE) measured in two adjacent wells, 15 m apart from each other along the main flow direction in the aquifer. From earlier tracer experiments you are pretty sure that the two wells are located on the same streamline, that is, they see the same water passing by, although not at the same time. 

Elmore, D., Bhattacharyya, M. H., Sacco-Gibson, N., and Peterson, D. P. (1990). Calcium-41 as a long-term biological tracer for bone resorption. Nucl. Instrum. Methods Phys. Res. B52 531-535. 

An automated tracer injection system was utilized to dispense tracers into the fracture regime of well 4014 under natural gradient conditions (Figure 1.2(b)). Two long-term, steady-state natural gradient experiments, each with a duration of 1.5 to 2... 

Schematic of device employed to determine long-term diffusion of dyes through hair. A similar set-up could be used for measurement of drugs employing radioactive tracers by placing the drug in the lower chamber. Removing aloquots from the top at regular intervals and measuring the radioactivity would then determine the breakthrough time.

The coupled long-term simulation and data assimilation runs are structured as a sequence of coupled runs (6 h in data assimilation, 24 h in forecast mode) because the IFS needs a re-start from a meteorological analysis as often as possible. The CTM provides the tracer initial conditions of the IFS for the first forecasts. There are three modes of how the initial conditions for the GRG-tracers are obtained in the subsequent forecasts (see Fig. 10.2). 

The analytical procedures presented in this study are relatively simple and sample through-put through the mass spectrometer is reasonable (15 min per replicate). The results indicate that the method has promise as an alternative to radioisotope tracer methods. Long-term studies and studies with infants, children, and women are feasible without hazards to the subjects. 

Reorientation dynamics of molecular tracers in polymers is not only important for the understanding of slow relaxation phenomena in glassy polymers but plays also a critical role in practical problems such as molecular design of nonlinear optical materials with long-term stability based on dyes/polymers complexes. We show here the reorientation dynamics of molecular tracers in glassy polymers obtained by the armealing-after-irradiation method described below. These experimental results are compared to the local relaxation processes of glassy polymers obtained by the already established measurement techniques such as dielectric relaxation and solid state NMR. Finally, the molecular interpretation of the relaxation of free-volume distribution in polymers will be discussed. 

Phillips F. M., Mattick J. L., Duval T. A., Elmore D., and Kubik P. W. (1988) Chlorine-36 and tritium from nuclear weapons fallout as tracers for long-term liquid and vapor movement in desert soils. Water Resour. Res. 24, 1877-1891. 

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