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Article
Singular PDFs of a Dispersing Scalar in Turbulence
When a finite quantity of scalar of uniform concentration C m is injected at time t= 0 into a turbulent flow containing no scalar, the initial PDF (probability density function) of the concentration of the scalar...
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Article
Some Simple Statistical Models For Relative And Absolute Dispersion
Observations of the dispersion of a contaminant plume in the atmospheric boundary layer, obtained using a Lidar, are analysed in the coordinate frame relative to the instantaneous centre of mass of the plume, ...
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Article
A Concentration pdf for the Relative Dispersion of a Contaminant Plume in the Atmosphere
Observations of the dispersion of a contaminant plume in theatmospheric boundary layer, obtained using a Lidar, are analysedin a coordinate frame relative to the instantaneous centre of massof the plume. To im...
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Article
The High Concentration Tails Of The Probability Density Function Of A Dispersing Scalar In The Atmosphere
The distribution function for concentrations of a scalar pollutant dispersing in the turbulent atmosphere has a finite domain that is bounded above and below. Three methods, based on extreme value statistics, ...
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Article
Atmospheric diffusion: some new mathematical models
The paper reviews some recent theoretical work on the statistical properties of the distribution of concentration of an atmospheric pollutant. This work is based on elementary physics. There is emphasis on the...
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Article
Dosages from instantaneous releases of dense gases in wind tunnels and into a neutrally stable atmosphere
We study the doses generated by instantaneously released dense gas clouds. The dose is of practical importance since it is widely used as a measure of the harmful effect of an exposure. We take the doses from ...
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Chapter
Mathematical modelling
When migration occurs as the result of contact between a food and another material, the concentration of each migrant will normally vary from position to position within the food and will also normally change ...
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Article
Fluctuations in dense gas concentrations measured in a wind-tunnel
Concentration time series from FID (flame ionisation detector) sensors and catharometers downstream of an instantaneous release of dense gas contaminants are analysed by statistical methods. For each experimen...
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Article
The pitfalls of thresholding atmospheric dispersion data
Atmospheric dispersion data are invariably corrupted by random noise and perhaps baseline drift giving rise to unreal negative values. This paper shows that the indiscriminate use of thresholding can give rise...
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Article
The treatment of atmospheric dispersion data in the presence of noise and baseline drift
Recently large quantities of data from many different field experiments have become available to facilitate the examination of various proposed models of atmospheric dispersion. However, these data sets are in...
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Article
The structure and magnitude of concentration fluctuations
This paper is concerned with the science of turbulent diffusion and not, except incidentally, with its numerous practical applications. It discusses some recent research, particularly that by the authors and t...
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Chapter
The Structure and Magnitude of Concentration Fluctuations
This paper is concerned with the science of turbulent diffusion and not, except incidentally, with its numerous practical applications. It discusses some recent research, particularly that by the authors and t...
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Article
Exact solutions for the probability density function of turbulent scalar fields
The basic property of a turbulent scalar field is its probability density function p(θ x, t). Here, for the first time, some exact solutions for p(θ x, t) are derived and discussed. These apply to the case of a f...
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Book
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Chapter
Centres of mass
Previously we have considered only the motion of particles, which are defined to be bodies whose size does not influence their motion. In the remaining chapters we shall be concerned with bodies whose size has...
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Chapter
Coplanar forces acting on a rigid body
In Chapter 4 we discussed the conditions which ensure that a rigid body is in equilibrium under a set of coplanar forces. In the present chapter we consider sets of coplanar forces acting on a rigid body which...
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Chapter
Momentum, impact and impulse
The work in this chapter is again based on Newton’s laws, which are first used to establish the principle of conservation of momentum for systems of particles. We also study how to predict the consequences of ...
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Chapter
Statics
The purpose of this chapter is to study the conditions under which particles and rigid bodies can rest in equilibrium, that is without moving. This branch of mechanics is called statics.
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Chapter
The motion of a rigid body about a fixed axis
The purpose of this final chapter is to investigate the motion of a rigid body turning about a fixed axis. We shall suppose that the axis is smooth, so that its bearings do not exert any frictional couple and ...
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Chapter and Conference Paper
The Incorporation of Wind Shear Effects into Box Models of Heavy Gas Dispersion
Box models are widely used in predicting the potential hazards associated with the accidental release of heavy gas clouds, and this paper discusses whether, and how, such models should be amended to incorporat...
