A method for quantitative measurements of gas and liquid distributions is demonstrated using simultaneous x-ray fluorescence and radiography of both phases in an atomizing coaxial spray. Synchrotron radiation at 10.1 keV from the Advanced Photon Source at Argonne National Laboratory is used for x-ray fluorescence of argon gas and two tracer elements seeded into the liquid stream. Simultaneous t...

[1] The SOLAS Air-Sea Gas Exchange (SAGE) Experiment was conducted in the western Pacific sector of the Southern Ocean. During SAGE, gas transfer velocities were determined using the He/SF6 dual gas tracer technique, and results were obtained at higher wind speeds (16.0 m s"1) than in previous open ocean dual tracer experiments. The results clearly reveal a quadratic relationship between wind s...

[1] Gas phase miscible displacement experiments were conducted to quantitatively investigate the advective and dispersive contributions to gas phase transport in unsaturated porous media over a range of soil water contents. Furthermore, the independence of measured dispersivity values was evaluated through comparison of nonreactive and reactive tracer transport. Methane was used as a nonreactiv...

Recent studies showed that nasal high flow (NHF) with or without supplemental oxygen can assist ventilation of patients with chronic respiratory and sleep disorders. The hypothesis of this study was to test whether NHF can clear dead space in two different models of the upper nasal airways. The first was a simple tube model consisting of a nozzle to simulate the nasal valve area, connected to a...

In studies where D-(-)-3-hydroxy[4,4,4-2H3]butyrate is employed as isotopic tracer in vivo, we have described a selected ion monitoring, gas-liquid chromatography-mass spectrometry micromethod which measures [2H3] tracer enrichment in 3-hydroxybutyrate and acetoacetate from 300-microliters blood samples. For plasma samples in the physiologic range, intra- and interassay precisions for each keto...

Robust measurements of porous-medium tortuosity are one of the many components needed for accurate characterization and prediction of fluid flow and contaminant transport in the subsurface. A gasphase diffusive tracer-test method is evaluated for the in-situ measurement of tortuosity in the vadose zone. This technique presents an alternative to employing widely-used correlations to estimate tor...

Steady and transient mass transport phenomena within an inverted, stagnation-flow, cold-wall CVD reactor were investigated by observing the concentration of a tracer species (CH4) with in situ Raman spectroscopy. The transient studies revealed that the use of matched reactor inlet velocities is crucial to minimize recirculating flow patterns and that the magnitude of the gas velocity is also im...

To monitor the gas and solid streams in a downcomer of a J-valve in a CFB, the simultaneous measurement technique using the oxygen gas tracer, the hot particle tracer and the pressure drop was developed. By using this novel measurement technique, the dependence of the solid flow on the gas flow in the moving bed in the downcomer of J-valve was investigated. The pressure profile and the pressure...

We investigate the microstructural and microrheological response to a tracer particle of a two-dimensional colloidal suspension under thermodynamic conditions close to a liquid-gas phase boundary. On the liquid side of the binodal, increasing the velocity of the (repulsive) tracer leads to the development of a pronounced cavitation bubble, within which the concentration of colloidal particles i...