Dispersal of materials

Dispersion of material following timed release in the colon using Pulsincap devices. Mean s.d. 

To illustrate the application of the Monte Carlo method, we consider the problem of simulating the dispersion of material emitted from a continuous line source located between the ground and an inversion layer. A similar case has been considered by Runca et al. (1981). We assume that the mean wind u is constant and that the slender-plume approximation holds. The line source is located at a height h between the ground (z = 0) and an inversion layer (z = Zi). If the ground is perfectly reflecting, the analytical expression for the mean concentration is found by integrating the last entry of Table II over y from -< to -Hoo. The result can be expressed as... 

The dispersal of material by spraying or by dusting of solid particles plays an important role in combustion technology. Large industrial boilers or furnaces employ oil fuel... 

But not only mercury is released by mining. Mn ore mining activities taking place in the Brazilian Amazon basin as open pits (for instance in the Serra do Navio, Amapa State), represent a potential source of associated ferrous metals (such as Ni, Cr, Cu, As). Acid mine drainage contains dissolved and particulate metals in toxic concentrations, affects the pH of streams and mobilizes metals. Moreover, wind dispersal of material from unstable spoil heaps can result in local or regional atmospheric contamination. Despite the likely importance of this source in the environment, it is currently not possible to estimate the quantities of trace... 

A model for the bulk effective resistivity of a dilute suspension (disperse phase) of noninteracting conducting spheres (not necessarily mono-dispersed) of material resistivity 9id and void fraction ad suspended in a continuous medium of material resistivity 9ic was derived by Maxwell (1954). His result is... 

The result of sludge formation and disposal is not only a return to the combined state i.e. metal hydroxides, oxides and other compounds but a dispersal of material and energy (figure 1). 

There are several primary meteorological measurements necessary in assessing atmospheric transport and mixing characteristics as related to the dispersion of material in the atmosphere. Those related to the wind are ... 

The occurrence of some materials in the form of a colloidal dispersion can introduce or enhance safety hazards. Considering that the dispersion of a material down to colloidal size results in a high-specific surface area, chemical reactivity in this state may differ considerably from that of the identical macroscopic material with less surface area. The dispersion of material down to the nanoscale regime has been the subject of even more concern. 

Question by D. H. Tantam, British Oxygen Research and Development Does alloying or dispersion of materials such as bronze dispersion in Teflon have any effect on the crystallinity method described ... 

Pairs with a particle-reactive parent and a mobile daughter, suitable to study dispersion of material released from the seafloor into the bottom water. Applications include deep-sea mixing ( Rn, Ra) and the advective transport between shelves and the inner ocean ( Ra). 

Chemical reactions can be violent can cause explosions, dispersion of materials and emission of heat. 

The adsorption of surfactants onto a clean nonpolar surface must occur with the hydrophilic group oriented outward into the aqueous phase. Adsorption, therefore, will always result in an increase in the hydrophilic character of the surface. Such action is responsible for the generally increased dispersibility of materials such as carbon black in aqueous surfactant systems, and the stability of aqueous latex polymers in paints. The action of surfactant adsorption onto colloidal surfaces can be useful to destabilize as well as stabilize systems. It may be useful, for example, to break an aqueous dispersion, to isolate the dispersed material, or to facilitate the process of separating dispersed solids in the sewage treatment process, although polymers and polyvalent cation salts are most commonly employed in such... 

---