Visible fumes

O Are there visible fumes at any times during the operation ... 

Sample Preparation Transfer 2.0 g of sample into a clean, 100-mL glass beaker, add 25 mL of 70% (v/v) nitric acid, cover with a watch glass, and heat at low to moderate heat on a hot plate in a fume hood for 2 h. Remove the watch glass, and continue to heat until the sample is dry with no visible fumes. Add 0.5 mL of 70% (v/v) nitric acid, and heat to dryness. Cool to room temperature, and add 2 mL of 20% (v/ v) hydrochloric acid and 2 mL of 0.1M EDTA. Quantitatively transfer the solution to a 25-mL volumetric flask, dilute to volume with water, and mix. 

Antimony pentachloride, SbCls, is a liquid having a freezing point of 2.8 °C and a boiling point of 140 °C. When absolutely pure, the liquid is colorless, but commercial SbCls is usually yellowish. SbCls has a high density (2.35 g/cc), and in humid air its vapor reacts with water to form visible fumes of hydrochloric acid mist and Sb20s particles ... 

The explosive is heated at 100 for eight hours each day until visible fumes appear. The test has subsequently been used in Holland in a slightly altered form. A quantity (usually 3 g.) of explosive is heated to 95, first for four hours in an unstoppered flask, and then for e ht-hourly periods. In general nitrocellulose requires fourteen to twenty-four daily periods. The test is stated to give good results for ungelatinised nitrocellulose, but to be less satisfactory for propellants. 

TAKING PRESSURE READINGS TO CONTROL R6 DURING VISIBLE FUMES... 

While monitoring for visible fumes, if you have a metallic taste in your mouth ... 

Table 4.45 A cost estimate for installation of an abatement system for visible fumes during...

For minimum interference between the elements, the heavier group is analyzed first. The minute residue from the column fraction is dissolved in 2 drops of 2 N HCl (or HNO3). One drop of this solution is deftly transferred with a quartz micropipette onto the previously cleaned side (sample) filaments of a triple filament, solid source mass spectrometer, (Inghram and Chupka 1953, Roboz 1968, White 1968, and Chait 1972). For this operation, the center or ionizing filament is withdrawn from its normal position to keep it free of sample. The sample is dried on the side filaments by heating each in turn at about 1.5 amps (for rhenium ribbon 0.025 x 0.76 mm). Completion of drying is conveniently indicated by a sudden drop in filament current corresponding to an increase in resistance with temperature. This is preceded sometimes by the emission of visible fumes. 

Metallurgical equipment has long been an obvious source of air pollution. The effluents from metallurgical furnaces are submicron-size dusts and fumes and hence are highly visible. The emissions from associated coke ovens are not only visible but odorous as well. 

Airborne particulates include dust, fume and aerosols. Many such particles are invisible to the naked eye under normal lighting but are rendered visible, by reflection, when illuminated with a strong beam of light. This is the Tyndall effect and use of a dust lamp provides a simple technique for the rapid assessment of whether a dust is present, its flow pattern, leak sources, the effects of ventilation, etc. More sophisticated approaches are needed for quantitative data. Whether personal, spot or static sampling is adopted will depend upon the nature of the information required. 

Obscuration The concealing from sight lack of visibility due to dust, fumes, or smokes. 

The chromatogram is observed and documented as soon as the spots are readily visible. The iodine can then be allowed to evaporate from the chromatogram (fume cupboard ). The chromatogram can then be subjected to further reactions or processes after this reversible reaction. 

Fumes are defined in the 1956 Act as being smaller than dust and thus are a constituent of smoke if visible and smaller than 76 pm. However, fumes are traditionally classified as being smaller than I pm (see Table 45.1). 

Ambient air contains many solid impurities, ranging from visible grit down to fine dusts, smokes and fumes [10]. An air-conditioning system will aim to remove a proportion of these, depending on the application. There are three reasons for air filtration ... 

Extracts of these fat samples were treated with sodium sulfate-concentrated sulfuric acid mixture and fuming acid by the method described by Schechter et al. 5) in order to separate the organic-chlorine compound from the fatty materials. An infrared spectrum from 7 to 15 microns on carbon disulfide solutions of the residues from the fat qualitatively identified the organic-chlorine compound as toxaphene. All the bands of toxaphene in this spectral region were plainly seen in the treated steer extract, whereas none of the absorption bands were visible in the untreated steer extract. 

The fumes given off from hot or previously heated mbber, a very complex mixture. Exposure to mbber fumes may be a factor in the increased incidence in certain types of cancer and also in the causation of some other diseases. Fume comprises visible and invisible components. 

The aerosol (visible) fraction is mbber fume as defined by the UK HSE, i.e., the fume evolved in the mixing, milling and blending of natural mbber and mbber or synthetic elastomers, or of natural mbber and synthetic polymers combined with chemicals, and in the processes which convert the resultant blends into finished process dust products or parts thereof, and including any... 

Metal fume agents are odorless solids dispersed as aerosols from incendiary devices. Depending on various factors, the aerosol may or may not be visible. 

Place (he bottle with contents in a chamber maintained at 65.5°il°C (See Fig oa p 28 of Ref 12 and on p 49 of Ref 13), the air in which is preferably maintained in constant circulation After (he bottle with contents has been heated for 24 hrs, reseat (he stopper. Make daily observation of the appearance of the sample and note the number of days required to cause (he liberation of visible reddish or brownish fumes of oxides of nitrogen Note It has been customary to consider any proplnt having a test value of 90 days or less to be of definitely impaired stability and any proplnt having a test value of 20 days or less to be sufficiently unstable as to require destruction or salvage... 

German 132° Stability Tost. This test has been used in Germany for testing NC and powders. The test was formerly carried out at 135°, but the temperature was lowered to 132° and the observation was often confined to the visible brown fumes. Sometimes the test was run using a strip of litmus paper. The test is essentially the same as the German 135° Stability Test (qv)... 

When testing smokeless propellants, heating may be continued in order to determine the time at which visible "red fumes (RF) are evolved. The test is usually also extended to a total of 5 hours heating in order to determine if the proplnt explodes... 

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