Tracer responses in gas-liquid, two-phase flow through a fractured layer are discussed. Experiments were carried out using a glass bead bed in a cylinder. In the results, over a wide range of flow conditions of particle size, fluids-flow velocity, and water saturation (Sw), one of three types of liquidand gas-flow pattern was obtained: a single-phase (water) flow with entrapped gases, a bubble ...

Flow-injection analysis, founded on an approach that is entirely different from continuous-flow analysis, involves use of three principles: sample "injection," controlled dispersion of sample (rather than a dispersion retarded with gas bubbles), and reproducible timing. The conditions governing the dispersion of the sample in the flowing carrier stream are considered, and we illustrate how the ...

This paper presents experimental and computational investigation of the dispersion mechanisms of a passive-type tracer gas, done in the scaled, three-dimensional model of a street canyon. At a low wind speed of 1.67m/s and neutral atmospheric conditions, dispersion of pollutant has been investigated within an isolated street canyon at an aspect ratio of 1 for perpendicular wind orientation (90)...

This study explored the health hazard of those exposed to methylene chloride by assessing its atmospheric concentration when a tear gas mixture was aerially dispersed. The concentration of methylene chloride ranged from 311.1-980.3 ppm (geometric mean, 555.8 ppm), 30 seconds after the dispersion started. However, the concentration fell rapidly to below 10 ppm after dispersion was completed. The...

1 MISCELLANEOUS (E.G., ARTIFICIAL SNOW) 2 FIRE-EXTINGUISHING 3 .Foam or gas phase containing 4 .Gas generative, chemically 5 ..Dry, combustion type 6 ..Low temperature chemically interreactive 6.5 ...Foam-stabilizant or colloidstabilizant containing 7 ..Carbonates or ammonium salts containing or pyrolytic 8 .Volatile or gas charged liquids containing 8.05 .Foam-stabilizant or colloidstabilizant...

In some instances, it is inevitable that large amounts of potentially hazardous chemicals like chlorine gas are stored and used in facilities in densely populated areas. In such cases, all safety issues must be carefully considered. To reach this goal, it is important to have accurate information concerning chlorine gas behaviors and how it is dispersed in dense urban areas. Furthermore, mainta...

In this paper we present a prototype instrument for remote open-path detection of nitrous oxide. The sensor is based on a 4.53 μm quantum cascade laser and uses the chirped laser dispersion spectroscopy (CLaDS) technique for molecular concentration measurements. To the best of our knowledge this is the first demonstration of open-path laser-based trace-gas detection using a molecular dispersion...

The SAURON integral field spectrograph was used to observe the central area of the barred spiral galaxy M100 (NGC 4321). M100 contains a nuclear ring of star formation, fueled by gas channeled inward by the galaxy's bar. We present maps of emission line strengths, absorption line strength indices, and the gas velocity dispersion across the field. The Hβ emission is strongest in the ring, along ...