Sources Producing Plumes

1 Weather Effects When following plumes to a source, weather can be a major factor. Obviously, this applies in water as well as in air. When turbulence is heavy, the plume will become more dispersed. This turbulence can result from a temporary, weather-induced condition, but may force delay in plume tracing. Judging the degree of turbulence in water is somewhat easier than in air, simply because we can see the water. 

Substantial research on environmental pollution plume persistence and dispersion in air has produced a classification system called Pasquill s stability classes for plume stability in air. Unfortunately, the system does not apply as directly as we might wish since it applies at the much larger scale of stack exhausts and the like. However, some insight from the system is available. 

Daytime Solar Heating Nighttime Cloud Cover 

Wind Much Some Slight Sparse Heavy 

Calm Most Unstable Very Unstable Unstable Moderately Stable Most Stable 

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Cooling-Tower Plumes. An important consideration in the acceptabiHty of either a mechanical-draft or a natural-draft tower cooling system is the effect on the environment. The plume emitted by a cooling tower is seen by the surrounding community and can lead to trouble if it is a source of severe ground fog under some atmospheric conditions. The natural-draft tower is much less likely to produce fogging than is the mechanical-draft tower. Nonetheless, it is desirable to devise techniques for predicting plume trajectory and attenuation. 

Figure 2 presents a schematic view of the ion source region in the PAI configuration. A second high-irradiance, frequency quadrupled pulsed Nd—YAG laser is focused parallel to and above the sample surface, where it intercepts the plume of neutral species that are produced by the ablating laser. Appropriate focusing optics and pulse time-delay circuitry are used in this configuration. 

Recent developments in the field-testing procedure have demonstrated that a motor-driven 35-mm camera at up to three frames per second produces superior results to a movie camera.The analysis of the film is carried nut by scaling the distance that fume advances from one consecutive photogi aph to the next. The diameter of the plume as a function of the distance above the source can be scaled directly off the photograph. 

Yokoi (1960) [3], singly produced a small book as a report, which carefully investigated point, line and finite heat sources with eventual applications to the hazard from house fire and window flame plumes. 

Plumes in Water Several fine researchers have approached the study of underwater plumes with different objectives. While all this work is undoubtedly instructive, a series of articles [28-32] produced by Webster and Weissberg and their colleagues may apply most directly. They have examined the structure [28] of plumes in controlled experiments and produced photographs of dye plumes to study their development. They also took the point of view of a hungry crab [32], In its attempt to find the food source indicated by the plume, the crab manipulates its sensors within the plume. The structure of the plume makes it necessary. Chapter 5 is devoted to a description of these plumes. 

Although there have only been a few studies to date, it has been suggested that coastal plumes (Turner et al., 1996 Simo et al., 1997) and estuaries (Iverson et al., 1989 Cerqueira and Pio, 1999) may be important atmospheric sources of DMS. DMS, a compound produced by certain phytoplankton, has been shown to have possible implications for climate control once released into the atmosphere (Charlson et al., 1987). DMS is formed by cleavage of dimethylsulfoniopropionate (DMSP) (Kiene, 1990). In fact, DMSP, shown to be correlated with bacterial activity, may provide as much as 100% of the sulfur and 3.4% of the carbon required for bacterial growth in oceanic waters (Kiene and Linn, 2000). Other sulfur compounds such as COS and carbon disulfide (CS2) have also been shown to be possible sources of S in estuaries. For example, significant concentrations of COS and CS2 were found in four European estuaries, 220 150 and 25 6 pM (Sciare et al., 2002). COS is the most abundant sulfur compound in the... 

Although there have only been a few studies to date, it has been suggested that coastal plumes and estuaries may be important atmospheric sources of DMS. DMS, a compound produced by certain phytoplankton, has been shown to have possible implications for climate control once released into the atmosphere. 

Like many other insects, moths attract mates by long-distance pheromones. Females produce these pheromones in specialized abdominal glands. Chemically, they are acetates, often active in precise mixtures of geometric isomers. Males fly upwind, following the females pheromone plume to the somce, and mating ensues. In a typical experiment, a female moth, or just the pheromone, serves as odor source. An air current from that source helps to attract males who fly upwind to the pheromone source and attempt to mate. With this technique, we can compare the effects of known pheromones from different, related species on one species (species specificity). We can also test the attractiveness of different compounds that are stracturally similar to a known pheromone. In the laboratory, a wind tunnel, where available, is ideal, for this experience. 

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