Fogging plate

Fig. 5 View of the cooled (15 °C) fogging plate (15 cmxl5 cm) for sampling semivolatile organic compounds. Source Uhde et al. [71]...

Rii - Rj4 reflectometer readings for the fogged plate, % Rfli - Ro4 reflectometer readings for the unfogged plate, %... 

The linear relation between the PSL signal and neutron fluence was established to exist over three decades up to 6. lO cm. The IP-ND can be used as fast and efficient neutron monitors at rather low neutron fluxes. However, for neutron dosimetry individual IP-ND must be calibrated individually since their sensitiviy can differ from one plate to another. In Gd/film based direct NR the film fog below the exposure dose of about 8.10 cm is the limiting factor. 

Nature of a Fog. Fog, like smoke, is a colloid. Once a fog is formed, it is very difficult to knock down. It will go right through packed columns, mist eliminators, or other such devices. Special devices are required to overcome a fog, such as an electric precipitator with charged plates. This can overcome the zeta potential of the charged particles and make them coalesce. 

Ni-30 Cu Alloy 400 also undergo fogging, but alloys containing 15% Cr or more do not exhibit this phenomenon. Fogging is prevented by a very thin film of chromium deposited on the surface—a fact which forms the basis for the bright appearance of decorative chromium-nickel plate (see Sections 13.7 and 13.8). 

FIGURE 17.2 Henri Becquerel discovered radioactivity when he noticed that an unexposed photographic plate left near some uranium oxide became fogged. This photograph shows one of his original plates annotated with his record of the event. 

In a fog-spray tank, plating chemicals clinging to parts are recovered by washing them with a fine water-mist. The solution that collects in the fog-spray tank is returned to the process tank as needed. The added water helps to offset evaporative losses from the process tanks. 

In barrel plating, the barrel should be rotated for a time just above the plating tank in order to reduce the volume of dragged-out chemical. Holes in the barrels should be as large as possible to improve solution drainage while still containing the pieces. A fog spray directed at the barrel or its... 

Salt Spray Test Panels coated with the standard chromate conversion coating and CMT were compared with each other in their corrosion resistant properties in several ways. The conventional 5% NaCl/S02 fog chamber tests showed excessive corrosion and pitting within one week on chromate conversion coated (COC) 7075-T6 A1 alloy panels. The CMT coated panels were almost uncorroded and without any pits. The plates in Figure 1 show the conditions of the panels after 7 and 14 days exposure in this environment. Even after 14 days exposure the CMT panels were still far better than COC panels. 

The apparatus described in Figure 7.5 was used for the accumulation of SVOCs. The accumulation capacity during the experiments amounted to 10 pg of film mass per glass plate per hour at a constant inside air temperature of 65 °C. Examples of SVOCs found in fogging films are listed below ... 

Production equipment that cannot be sterilized must be sanitized and disinfected by an appropriate method. This can be done by use of biocides like alcohols (70%), hydrogen peroxide, or formaldehyde-based chemicals or a combination of these. These can either be used for surface disinfections by wiping or spraying or even better by use of gas or dry fog systems for application of the disinfectants. The effect of cleaning and sanitation should be monitored. Microbiological media contact plates can be used to test critical surfaces, as inside the hot cells or glove boxes. The test samples must then be handled and monitored as radioactive contaminated units. 

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