Smoke demonstrations

Early in September 1944, and before any decision was reached on the control of the smoke units, a group of Sixth Army officers witnessed a smoke demonstration at Lae which featured the recently arrived M2 mechanical generator, smaller and more economical and efficient than its predecessor. Without exception, the officers were most enthusiastic about the capabilities of the new mechanical gen-... 

The analysis of cigarette smoke for 16 different polyaromatic hydrocarbons is described in this experiment. Separations are carried out using a polymeric bonded silica column with a mobile phase of 50% v/v water, 40% v/v acetonitrile, and 10% v/v tetrahydrofuran. A notable feature of this experiment is the evaluation of two means of detection. The ability to improve sensitivity by selecting the optimum excitation and emission wavelengths when using a fluorescence detector is demonstrated. A comparison of fluorescence detection with absorbance detection shows that better detection limits are obtained when using fluorescence. 

Precipitators are currently used for high collection efficiency on fine particles. The use of electric discharge to suppress smoke was suggested in 1828. The principle was rediscovered in 1850, and independently in 1886 and attempts were made to apply it commercially at the Dee Bank Lead Works in Great Britain. The installation was not considered a success, probably because of the cmde electrostatic generators of the day. No further developments occurred until 1906 when Frederick Gardiner Cottrell at the University of California revived interest (U.S. Pat. 895,729) in 1908. The first practical demonstration of a Cottrell precipitator occurred in a contact sulfuric acid plant at the Du Pont Hercules Works, Pinole, California, about 1907. A second installation was made at Vallejo Junction, California, for the Selby Smelting and Lead Company. 

The first experiment with the electrostatic gas cleaning was made in 1824, when Hohlfeld show that a fog was cleared from a glass jar which contained an electrically charged point electrode. Similar demonstrations were published in the 19th century, an example being the precipitation of tobacco smoke in a glass cylinder by Guitard (1850). 

The proplnts described above are in the realm of prior art and depict those NC proplnts with low smoke potential that are used primarily as gun proplnts. Recent research and development work has been concentrated on creating both gun proplnts and rocket proplnts with reduced smoke output in order to foil countermeasures. Lavitt (Ref 76) found that the concurrent use of optimum proportions of lead stearate and sodium barbiturate in double-base proplnts resulted in a marked reduction in smoke output. This was attributed to the synergistic interaction of the two salts to produce more complete oxidation of the exhaust products. The importance of using the optimum ratio of the two catalysts is demonstrated by the higher smoke values shown in Table 4 for Propellants 105, 106 and 107, when compared to other... 

Research on CBl knockout mice demonstrated the pivotal role of CBl receptors in cannabis dependence knockout mice have been shown not to self-administer cannabinoids (Ledent et al. 1999) and also to fail to exhibit symptoms ofSRl417l6A-precipitated withdrawal (Ledent et al. 1999 Lichtman et al. 2001). Although the research summarized earlier is consistent in reporting the occurrence of a variety of withdrawal symptoms following cessation of exposure to cannabinoids (which were injected), precipitated withdrawal in mice following chronic exposure to marijuana smoke was more recently reported (Lichtman and Martin 2002). 

Radioisotope-labeled nitrosamines have proven valuable in development of analytical methods and for demonstrating efficiency of recovery of nitrosamines from tobacco products and smoke (37-39). The very high specific activity required for low part-per-billion determinations has discouraged most analysts from using this approach. Unless a radiochromatographic detector with adequate sensitivity is available, samples must be counted independently of the final chromatographic determination, and one of the advantages of internal standardization, correction for variation in volume injected, is lost. 

According to EPA (IRIS 1999), the available human epidemiological studies lack quantitative exposure data for lead and for possible confounding exposures (e.g., arsenic, smoking). Cancer excesses in the lung and stomach of lead-exposed workers that are reported are relatively small, dose-response relationships are not demonstrated neither is there consistency in the site of cancers reported. EPA (IRIS 1999) concluded that the human data are inadequate to refute or demonstrate the potential carcinogenicity of lead exposure. 

Two recent studies seem to demonstrate that lycopene is able to counteract the dangerous effects of smoke by acting through a mechanism involving IGF-1 and/or Akt pathways. In the lung of ferrets, it has been shown that cigarette smoke-induced lesions (e.g., squamous metaplasia,... 

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