We present an alternative explanation for the nature of turbulence in molecular clouds. Often associated with classical models of turbulence, we instead interpret the observed gas dynamics as random motions, induced when clumpy gas is subject to a shock. From simulations of shocks, we show that a supersonic velocity dispersion occurs in the shocked gas provided the initial distribution of gas i...

The broadening of inhaled aerosol boluses (aerosol bolus dispersion) during respiration provides a noninvasive measure of convective gas mixing in the lungs. In this study, the sensitivity and specificity of this technique for the diagnosis of early lung impairment due to cigarette smoking was evaluated. Two hundred and sixteen randomly selected subjects (126 smokers and 90 nonsmokers) were inv...

We have studied the kinematics of the ionized gas in the nearly face-on galaxy NGC 3938 by means of observations made with the Fabry–Perot interferometer TAURUS II at the William Herschel Telescope, using the Hα line. We have been able to produce high-resolution velocity and velocity-dispersion maps which allow us to make a detailed study of the kinematics of the ionized gas. In particular we h...

−− A simplified approach is presented to the transient atmospheric dispersion of accidental releases of natural gas, originated by leakages in pressurized ducts on sea level. In this scenario, shutoff valves are used for instantaneous shutdown of tube operation, isolating the harmful inventory, whose transient release is simulated providing estimations of gas instantaneous atmospheric concentra...

We present the kinematics and photometry of the stars and of the ionized gas near the centre of the S0 galaxy NGC4036. Dynamical models based on the Jeans Equation have been constructed from the stellar data to determine the gravitational potential in which the ionized gas is expected to orbit. Inside 10 ′′ , the observed gas rotation curve falls well short of the predicted circular velocity. O...

Abstract This paper reviewed the studies of livestock odour dispersion modeling including odor sources, odor emission rate, odor characteristics and measurements, odor dispersion modeling methods, and methods and results of adapting industrial air dispersion models for livestock odor dispersion simulations. The Gaussian plume models, Puff models, Fluctuating models and other models that have be...

Hydrocarbon contamination of unsaturated soils has been a serious environmental problem for decades. Two of the most common methods of remediating these sites are soil vapour extraction (SVE) and bioventing. Predictive models have been developed for the SVE and bioventing processes in order to estimate mass transfer coefficients for experimental systems and clean up times for field sites. These...