Wind-trajectory method

Not all emissions come from stacks. Often the unducted fugitive process emissions and entrained dust are very Important, but there are no good ways of studying them. Perhaps the best way would be the use of ground-level samplers controlled by wind-sector devices that turn on the samplers only when the wind Is in the desired direction and above some minimum velocity. The wind-trajectory method noted below may also be of value for study of fugitive emissions. 

The wind trajectory method Is a supplement to other methods, not a replacement, as It has some weaknesses. Although we are already certain of being able to pick up emissions from Cu and Zn smelters, a pigment plant and steel plants, the method may not work on sources that have no dominant element. It may not work on widely distributed, ubiquitous sources such as gravel quarries, or on sources with very tall stacks. Despite these limitations, the method will be a useful supplement to the others and It should be fully exploited. 

Approaches used to model ozone formation include box, gradient transfer, and trajectoty methods. Another method, the particle-in-cell method, advects centers of mass (that have a specific mass assigned) with an effective velocity that includes both transport and dispersion over each time step. Chemistry is calculated using the total mass within each grid cell at the end of each time step. This method has the advantage of avoiding both the numerical diffusion of some gradient transfer methods and the distortion due to wind shear of some trajectory methods. 

In this study we have employed the simultaneous collection of atmospheric particles and gases followed by multielement analysis as an approach for the determination of source-receptor relationships. A number of particulate tracer elements have previously been linked to sources (e.g., V to identify oil-fired power plant emissions, Na for marine aerosols, and Pb for motor vehicle contribution). Receptor methods commonly used to assess the interregional impact of such emissions include chemical mass balances (CMBs) and factor analysis (FA), the latter often including wind trajectories. With CMBs, source-strengths are determined (1) from the relative concentrations of marker elements measured at emission sources. When enough sample analyses are available, correlation calculations from FA and knowledge of source-emission compositions may identify groups of species from a common source type and identify potential marker elements. The source composition patterns are not necessary as the elemental concentrations in each sample are normalized to the mean value of the element. Recently a hybrid receptor model was proposed by Lewis and Stevens (2) in which the dispersion, deposition, and conversion characteristics of sulfur species in power-plant emissions... 

Carrino L, Polini W and Sorrentino L (2004) Method to evaluate winding trajectories in robotized filament winding, J Compos Mater 38 41-56. 

For a given set of initial conditions Zh t = 0), k = 1,. ..,4, the solution of (3.2.6) defines a system trajectory. Since the energy is conserved, this trajectory winds in a three-dimensional sub-space of the four-dimensional phase space of the pendulum. It is not easy to imagine the motion in such a high-dimensional space, and we need to devise a visualization method that gives some clues as to the qualitative nature of the system trajectories. One particularly useful method, the method of the surface of... 

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