Dispersion Life expectation

Since most time-dependent failures have larger life dispersions, we must consider the maximum and minimum ratios of 4 1 and 40 1. Generally, relative life dispersion increases with the absolute value of MTBF. That is, wear items with a relatively short life expectancy such as rider rings on reciprocating compressors will have a comparatively smaller dispersion than components such as gear tooth flanks, which can be expected to remain serviceable for long periods of time. 

Lastly, dyes can be dispersed by expl charges. These generate colored clouds (about 10x20m) which are formed instantaneously and which have a life expectancy, depending on environmental conditions, from 65—85 seconds, whereas aerial burning of the aforementioned burning type produces streamers about one meter across and which last for about 57-120 seconds... 

BIOLOGICAL PROPERTIES Koc 5,181 leaching is only expected to be quick in sandy soils % degraded under anaerobic continuous flow conditions 4% in air, half of it may be broken down to other chemicals within 60 days in water, half of it may be broken down tc other chemicals within 30 days readily breaks down in soil considerable dispersion is expected did not biodegrade in an anaerobic culture incubated for 48 hrs 37°C under anaerobic conditions with domestic wastewater as the innoculum, 100% was removed after 7 days incubation 25°C soil, surface water, and aerobic half-lives 4 weeks-6 months ground water half-life 8 weeks-12 months anaerobic half-life 16 weeks-24 months can be detected in water by EPA method 612 methylene chloride extraction followed by concentration, gas chromatography plus electron capture detection, or EPA Method 625 gas chromatography plus mass spectrometry... 

An example of some of the newer regulations is the restriction against the use of the popular mud dispersant, chrome lignosulfonate. It is expected that this regulation is merely the initial step toward ruling out the use of all heavy metal salts commonly employed in the formulation of well fluids because of their toxicity to aquatic life and humans. This means that the use of zinc and lead, in addition to chromium, may not be allowed in the future. At least one major oil company has already taken steps in this direction by ruling out the use of heavy metal salts in any well fluid in their worldwide operations. 

The primary environmental fate mechanism followed by stored or buried HD is hydrolysis. Although HD is rapidly hydrolyzed (a half-life of 4 to 8 min at 25° C in distilled water has been reported [Bartlett and Swain, 1949]), the overall process of hydrolytic destruction is limited by the very low water solubility of HD. Intermediate hydrolysis products and/or water-insoluble thickeners that can coat or encapsulate droplets of mustard retard hydrolysis. Because of low water solubility and formation of intermediate products, bulk amounts of HD may persist undispersed under water for some time. However, HD dispersed as droplets or mist, as in the case of an aerial attack, is expected to hydrolyze rapidly in humid air. 

PROBABLE FATE photolysis not important except as photooxidation, C-Cl bond can photolyze slowly oxidation rapid tropospheric photooxidation by hydroxyl radicals yields many products, probable predominant fate hydrolysis too slow to be significant volatilization rapid volatilization is the major transport process, half-life from a model river 3 hr biological processes very low potential for bioaccumulation, and biodegradation is probably too slow to be significant evaporation from water 25°C of 1 ppm solution 50% after 24 min. and 90% after 83 min. evaporation half-life from 1 ppm aqueous solution 25 C, still air, and an average depth of 6.5 cm 24 min. adsorption to sediment probably not important considerable dispersal from source areas expected to occur... 

For small distances DLVO theory predicts that the van der Waals attraction always dominates. Please remember, the van der Waals force between identical media is always attractive irrespective of the medium in the gap. Thus thermodynamically, or after long periods of time, we expect all dispersions to precipitate. Precipitation might, however, be so slow that it exceeds the life span of any human observer. Once in contact, particles should not separate again, unless they are strongly hit by a third object and gain a lot of energy. 

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