Plume defined

Once illustrated on a map of the effluent plume, the ZPE can be seen visually as larger or smaller than the area of the plume defined by the isopleth for the 1% concentration of effluent (Environment Canada, 1999). The method is flexible in that any number of endpoints/descriptors can be used. However, redundancy in endpoints or descriptors should be scrutinized. 

If the cloud is wider than the width of the obstacle (i.e. > 2), and so its width and peak concentration are not significantly changed by the impact. If crz > H, its depth is also not much changed. But for a tall obstacle, if H/b > 2 and if the plume is narrow plume, defined by crz < b, then the cloud is diffused vertically in the wake, so that completely mixed up to the height of the building. 

The nature of these paraffins and their concentration in diesel fuel affect the three temperatures that characterize the cold behavior. The cloud point is the temperature at which crystals of paraffins appear when the temperature is lowered. The cold filter pluming point is defined as the temperature under which a suspension no ionger flows through a standard filter. Finally, the pour point is the temperature below which the diesel fuel no longer flows by simple gravity in a standard tube. These three temperatures are defined by regulations and the refiner has three types of additives to improve the quality of the diesel fuel of winter. 

Virtual Sources The previous equations apply to point source releases. Real releases, such as a boiling pool of liquid or a streaming jet of flashing hquid, involve a more complex geometiy One approach Guideline.s for Chemical Proce.s.s Quantitative Risk Analy.sls, AIChE, 1989, p. 87) is to define a virtual source upwind from the ac tual source such that the computed plume matches the real plume. However, to achieve this, a concentration at a centerhne point directly downwind must be known. 

Despite these limitations, mobile monitoring systems have been used to obtain useful information, such as the verification and tracking of the St. Louis, Missouri, urban plume. The measurement of a well-defined urban plume spreading northeastward from St. Louis is shown in Fig. 15-2 (7). These data were collected by a combination of instrumented aircraft and mobile vans. Cross-sectional paths were flown by the aircraft at increasing distances downwind. Meteorological conditions of low wind speed in the same direction helped to maintain this urban plume in a well-defined... 

Opacity is a function of light transmission through the plume. Opacity is defined as follows ... 

A particularly difficult aspect of the problem of diffusion of atmospheric pollution is the determination of the height to which a buoyant plume with an initial exit velocity will rise. Plume rise, which is defined as the distance between the top of the stack and the axis of the centroid of the pollutant distribution, has been found to depend on ... 

Determine exposure via groundwater define contaminant plume for evaluation of interception methods... 

Electromagnetic (EM) Conductivity Measures the electrical conductivity of materials in microohms over a range of depths determined by the spacing and orientation of the transmitter and receiver coils, and the nature of the earth materials. Delineates areas of soil and groundwater contamination and the depth to bedrock or buried objects. Surveys to depths of SO to 100 ft are possible. Power lines, underground cables, transformers and other electrical sources severely distort the measurements. Low resistivities of surficial materials makes interpretation difficult. The top layers act as a shunt to the introduction of energy info lower layers. Capabilities for defining the variation of resistivity with depth are limited. In cases where the desired result is to map a contaminated plume in a sand layer beneath a surficial clayey soil in an area of cultural interference, or where chemicals have been spilled on the surface, or where clay soils are present it is probably not worth the effort to conduct the survey. 

Nadeau, R., J. Lafornara, G. Klinger and T. Stone. Measuring Soil Vapors for Defining Subsurface Contaminated Plumes. Management of Uncontrolled Hazardous Waste Sites Proceedings, Hazardous Materials Control Research Institute, Washington, D.C., 1985. 

Pasquill defined six stabihty classes ranging from highly stable, low-turbulence Class F, to unstable, highly turbulent Class A, and he identified the surfece wind speed, intensity of solar radiation, and nighttime sky cover as being the prime factors controlling atmospheric stabihty. PasquiU then correlated observations of the behavior of plumes in terms of their dispersion with the... 

The use of a natural ventilation system assumes temperature stratification throughout the room height. Air close to heat sources is heated and rises as a thermal plume (Fig. 7.105). Part of this heated air is evacuated through air outlets in the upper zone, and part of it remains in the upper zone, in the so-called heat cushion. The separation level between the upper and lower zones is defined in terms of the equality of and G, which are the airflow rate in thermal plumes above heat sources and the airflow supplied to the occupied zone, respectively. It is assumed that the air temperature in the lower zone is equal to that in the occupied zone, and that the air temperature in the upper zone is equal to that of the evacuated air,... 

Defining the plume of the contamination was straightforward by using existing domestic wells and a few monitoring wells. However, determining the nature of the problem beneath the potliner pile and its vicinity was much more difficult. 

The presence of a lithosphere with a thickness up to 100 km above the plume head obscures observations that could be made in terms of heat flow, gravity field or seismic structure. Establishing the temperature and flow fields beneath a hotspot thus becomes a difficult exercise. Several key parameters (Fig. 2) are poorly constrained and mostly result from theoretical fluid dynamics model, which underlines their large uncertainty. The temperature anomaly within the hotspot region is generally estimated to be approximately 200 100°C with large uncertainties (Shilling 1991 Sleep 1990). These temperature anomalies will induce smaller densities in the plume and the flux of the density anomalies is called buoyancy flux as defined in (Sleep 1990) ... 

The modeling package, delivered to the EPA, includes nationwide data bases for emissions, dispersion meteorology, and population patterns. These data are used as input for a Gaussian plume model for point sources and a box model for urbanwide area sources. Prototype modeling is used for point sources that are too numerous to define individually. Building wake effects and atmospheric chemical decay are addressed. 

A tank has ruptured and a pool of benzene has formed. The pool is approximately rectangular with dimensions of 20 ft by 30 ft. Estimate the evaporation rate and the distance affected downwind. Define the plume boundary using the TLV-TWA of 10 ppm. It is an overcast day with a 9 mph wind. The temperature is 90°F. 

Passive puff or plume In addition to the restriction on plumes discussed above, there is an along-wind dispersion time scale given by td = 2Gjur where Gx is evaluated at the endpoint distance xe. The release can usually be considered a plume if ts > 2.5 fd, where ts is the source time scale defined above, and the release can be considered a puff if td > ts. For td< ts< 2.5 td, neither puff nor plume models are entirely appropriate the predicted concentration is considered the largest of the puff and plume predictions. 

Soil treatment, 25 834-843, 843-845 bioremediation, 25 835-836 electrokinetics, 25 843-844 ex situ bioremediation, 25 836, 842-843 in situ air stripping, 25 844 in situ bioremediation, 25 836-842 plume containment, 25 835 soil flushing, 25 844 soil vapor extraction, 25 844 sulfur use in, 23 591 vitrification, 25 844-845 Soil-vapor extraction defined, 3 759t... 

The behavior of nonaqueous phase liquids (NAPLs) as they enter the partially saturated subsurface from a land surface source follows two well-defined scenarios in one case, the physical properties of the NAPL remain unchanged, while in the second case, NAPL properties are altered during transport. In the case of dense NAPLs, the contaminant plume reaches the aquifer and is subject to longterm, continuous, slow local redistribution due to groundwater flushing-dissolution processes. These plumes become contamination source zones that evolve over time, often with major negative impacts on groundwater quality. 

A much-simplified classification, based on these tables, is shown in Table 4.6. The scale of interest is very different for trace chemical or odor plumes from that for which the original classification system was developed. Therefore, it is proposed that the simplified classification scheme of Table 4.6 will be sufficiently applicable to provide an indication of the more and the less favorable conditions for following plumes. In this presentation the lighter shading denotes those conditions that are generally more favorable darker shading indicates more instability and hence less well defined plumes. 

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