Groups and clusters contain a large fraction of hot gas which emits X-ray radiation. This gas yields information on the dynamical state and on the total mass of these systems. X-ray spectra show that heavy elements are present in the gas. As these metals must have been produced in the cluster/group galaxies and later transported into the gas, the metallicity is a good tracer for the transport p...

In July 2002, approximately 0.9 mol of sulfur hexafluoride (SF6) was injected into Newark Bay, NJ, a 14 km2 estuary that forms part of New York Harbor, to investigate circulation, mixing, and the transport and fate of solutes. The SF6 tracer was observed over 11 consecutive days using a high-resolution measurement system. Total tracer mass in the sheltered waters declined quasiexponentially at ...

Unidirectional, continuous airflow through the avian lung is achieved through an elaborate air sac system with a sequential, posterior to anterior ventilation pattern. This classical model was established through various approaches spanning passively ventilated systems to mass spectrometry analysis of tracer gas flow into various air sacs during spontaneous breathing in restrained ducks. Inform...

There is growing evidence that the properties of the molecular gas in the nuclei of starburst galaxies and in AGN may be very different from those seen in Galactic star forming regions and that a high kinetic temperature in the molecular gas may lead to a non-standard initial mass function in the next generation of stars. Unfortunately, among the fundamental parameters derived from molecular li...

[1] Two He/SF6 dual‐gas tracer injections were conducted during the Southern Ocean Gas Exchange Experiment (SO GasEx) to determine gas transfer velocities. During the experiment, wind speeds of up to 16.4 m s were encountered. A total of 360 He and 598 SF6 samples were collected at 40 conductivity‐temperature‐depth (CTD) rosette casts and two pumped stations. The gas transfer velocity k was cal...

The autoradiographic diffusible tracer technique for the measurement of local cerebral blood flow was originally designed for use with the radioactive, inert gas 131I-labeled trifluoroiodomethane and is applicable only with tracers that exhibit unrestricted diffusion through the blood-brain barrier. Because of the technical problems associated with the use of gaseous tracers, a suitable nonvola...

In October 2001, ,0.2 mol of SF6 was injected into the upper Hudson River, a modified natural channel with multiple dams, at Ft. Edward, N.Y. The tracer was monitored for 7 days as it moved ,50 km downriver. The longitudinal evolution of the tracer distribution was used to estimate one-dimensional advection s9.0±0.2 km d−1d and dispersion s17.3±4.0 m2 s−1d along the river axis. Comparison of th...

Turfgrass Research. The lysimeter is 4.0 m deep, 2.5 m in diameter, and contains a homogeneous packing of Vinton fine Experiments were conducted in a well-instrumented weighing lysand (sandy, mixed, thermic Typic Torrifluvents) with a mean simeter (2.5 by 4 m) to evaluate the efficacy of the gas-phase-partibulk density of 1.38 Mg m 3 and porosity of 0.47. Details tioning tracer method for measu...