Laboratory tracer tests

On the laboratory scale, it is usually safe to assume that a batch reactor is stirred to uniform composition, but for critical cases such as high viscosities this could be checked with tracer tests. 

Laboratory column experiments were used to identify potential rate-controlling mechanisms that could affect transport of molybdate in a natural-gradient tracer test conducted at Cape Cod, Mass. Column-breakthrough curves for molybdate were simulated by using a one-dimensional solute-transport model modified to include four different rate mechanisms equilibrium sorption, rate-controlled sorption, and two side-pore diffusion models. The equilibrium sorption model failed to simulate the experimental data, which indicated the presence of a ratecontrolling mechanism. The rate-controlled sorption model simulated results from one column reasonably well, but could not be applied to five other columns that had different input concentrations of molybdate without changing the reaction-rate constant. One side-pore diffusion model was based on an average side-pore concentration of molybdate (mixed side-pore diffusion) the other on a concentration profile for the overall side-pore depth (profile side-pore diffusion). 

Transferability of the results from this study to the Cape Cod natural gradient tracer test will provide information about the validity of laboratory experiments in providing information about onsite processes. Although actual values for some of the physical parameters determined in the laboratory may not apply to an aquifer because of scale differences between laboratory and field, conceptually realistic models such as the profile side-pore diffusion model may be able to simulate onsite transport conditions more accurately. 

Neretnieks 1. Interpretation of some in-situ tracer test experiments in fractured crystalline rock at Aspo hard rock laboratory. Paper presented at this congress, 2003... 

A series of tracer tests were performed at the Aspo hard rock laboratory in Sweden. The tests were performed in a well-characterised rock volume. In this paper two sets of converging flow experiments are discussed. One set is over a distance of about five meters, the TRUE-1 experiments. The other is over 14-33 m in the TRUE-block experiments. The site is in a drift at about 400 m below the ground (Byegard et al. 1998 and Andersson et al. 2001). 

The models for catalyst effectiveness in trickle bed reactors developed in this paper require explicit measurements or predictions of external contacting, ncE pore fill-up, rii In laboratory conditions this can be accomplished by tracer techniques (22, ). Fractional pore fill up may be determined by the difference in first moments of the impulse response tracer tests performed on two beds of same particle size and shape when one bed consists of porous the other of nonporous particles. Fractional pore fill-up can also be assessed from the measured volumetrically static holdup. External contacting is measured by adsorbable tracer tests on beds of nonporous particles ( ). In industrial conditions ncE hj would have to be evaluated from correlations. Unfortunately at present the existing correlations for ncE unsatisfactory since they were developed for fixed bed adsorbers with larger packing and correlations for m ate nonexistent but may be developed in the future. 

Kharaka YK, Carothers WW, Rosenbauer RJ (1983) Thermal decarboxylation of acetic acid implications for origin of natural gas. Geochim Cosmochim Acta 47 397-402 Knaepen WAI, Tijssen R, van den Berger EA (1990) Experimental aspects of partitioning tracer tests for residual oil saturation determination with FIA-based laboratory equipment. SPE Reservoir Eng 5 239-244... 

For example, the type test of a laboratory fume hood includes determination of the concentration at various points across the opening of the hodd by using various tracer source locations inside the hood. The commissioning test could concentrate on the measurements taken at one point in the opening with one source location. 

From the OPCW proficiency tests, it can be seen that from the seventh OPCW proficiency test (spring 2000) onward, Tracer has been the only FTIR technique for which use has been reported. Four laboratories have used this technique. At least two other laboratories working in the field of CWC... 

In laboratory tests using simulated HLW solution spiked with fission product tracers, Am and Cm, the denitration step proved to be a sensitive process, but Am/Cm recoveries of ca. 90% in the aqueous supernate could be realized under optimized conditions. Decontamination factors (DF) > 1000 for Zr, Nb, Mo, and 100 for Ru and Fe were obtained in the precipitation step. The solvent extraction cycle gave > 98% recovery of Am/Cm and DF > 10 for rare earths, Sr and Cs. Appreciable decontamination was also obtained for Zr/Nb (DF = 20), Ru (50), U (650), Pu (250), Np (800) and Fe (420). The ion exchange cycle served mainly for Am-Cm concentration and for removal of DTPA and lactic acid based on tests with europium as a stand-in for trivalent actinides, concentration factors of about 50 could be expected under optimized conditions. 

In most studies of the metabolism of vanadium, the metal has been introduced into test animals by intravenous or intraperitoneal injection of various salts containing a V tracer. Experiments in several laboratories, in which rats and mice were administered... 

Laboratory tests with Alipal CD-128 indicated that a steady-state reciprocal apparent viscosity of 0.2-0.4 cP (about equal to that of the oil) could be obtained and that surfactant retention by the reservoir rock would not be excessive (0.00056 lb surfac-tant/ft of rock permanent adsorption). Eventually, the following injection sequence was planned (1) 15 kg of NH4SCN tracer in 371 bbl of water, followed by a water spacer between the tracer and the subsequent surfactant solution (2) 2,764 bbl of 0.1% surfactant, intended to satisfy the adsorption requirements of the rock ... 

The sources of ionizing radiation are nuclear power plant, nuclear material processing, and radionuclide generation for nondestructive purposes. Medical and chemical laboratories use these radionuclides—for example, iodine, thallium, and barium—as tracers. The danger of mishandling these materials could cause release of these materials into the environment. Other than medical diagnostic tests for fracture of bones and constriction of blood vessels, these are used for the treatment of cancers. 

Several ELISA formats have been considered, and the one currently being tested is called the "hapten tracer" method. First introduced to this project by Dr. Freya Jung while a postdoctoral fellow in Dr. Hammock s laboratory, this method uses microtiter plates coated with a commercial preparation of goat anti-mouse antibody. Enzyme-labeled hapten competes with analyte for receptor sites on a mouse monoclonal antibody specific for the analyte. The amount of enzyme left after washing is inversely proportional to the... 

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