Wetting repeated

When the walls of a container are wetted repeatedly, an adhering layer of suspension particles may build up, and this subsequently... 

Use a rubber bulb to draw detergent solution to a level 2 to 3 cm above the calibration mark of the pipet. Drain this solution and then rinse the pipet with several portions of tap water. Inspect for film breaks repeat this portion of the cleaning cycle if necessary. Finally, fill the pipet with distilled water to perhaps one third of its capacity and carefully rotate it so that the entire interior surface is wetted. Repeat this rinsing step at least twice. 

The distribution of impurities over a flat sihcon surface can be measured by autoradiography or by scanning the surface using any of the methods appropriate for trace impurity detection (see Trace and residue analysis). Depth measurements can be made by combining any of the above measurements with the repeated removal of thin layers of sihcon, either by wet etching, plasma etching, or sputtering. Care must be taken, however, to ensure that the material removal method does not contaminate the sihcon surface. 

Two-phase suspension systems produce beaded products with broader particle-size distribution (e.g., 1-50 /rm). The microspherical particles usually need to be classified repeatedly to reduce the particle-size distribution in order to improve the resolution and efficiency in the separation for use in chromatography. The actual classification process depends on the size range involved, the nature of the beaded product, and its intended applications. Relatively large (>50 /rm) and mechanically stable particles can be sieved easily in the dry state, whereas small particles are processed more conveniently in the wet state. For very fine particles (<20 /rm), classification is accomplished by wet sedimentation, countflow setting, countflow centrifugation, or air classification. 

If the number of decks required is unreasonable from a height standpoint, the procedure must be repeated using a new assumed L /Gg, or a new approach, or a new wet bulb temperature, or some combination of these. 

The resin is supplied in moist condition, and should not be allowed to dry out particulate fracture may occur after repeated drying and re-wetting. 

Filter the wet resin and rinse with distilled water. Repeat the washing procedure until the washing water is neutral to pH paper. Rinse with three 100-ml portions of methanol. Evaporate off the remaining methanol in a rotary film evaporator under vacuum, rotating slowly at 40°C, until visibly dry. 

Air containing 0.005 kg water vapour per kg of dry air is heated to 325 K in a dryer and passed to the lower shelves. It leaves these shelves at 60 per cent humidity and is reheated to 325 K and passed over another set of shelves, again leaving at 60 per cent humidity. This is again repeated for the third and fourth sets of shelves, after which the air leaves the dryer. On the assumption that the material on each shelf has reached the wet-bulb temperature and that heat losses from the dryer may he neglected, determine ... 

Once the desired frost is achieved, the skin can be rinsed off with water, or cooled down with cool wet compresses which are applied to the skin. The wet compresses can provide a welcome relief to the burning induced by the peel. Unlike glycolic peels the water does not neutralize the peel, as the frosting indicates the end-point of the reaction rather, it dilutes any excess TCA. The compresses can be repeated several times until the burning sensation has subsided. Subsequently, a layer of ointment such as plain petrolatum or Aquaphor is applied and post-peel instructions and what to expect are reviewed with the patient prior to discharge to home. 

This type of catalyst is not limited to nickel other examples are Raney-cobalt, Raney-copper and Raney-ruthenium. When dry, these catalysts are pyrophoric upon contact with air. Usually they are stored under water, which enables their use without risk. The pyrophoric character is due to the fact that the metal is highly dispersed, so in contact with oxygen fast oxidation takes place. Moreover, the metal contains hydrogen atoms and this adds to the pyrophoric nature. Besides the combustion of the metal also ignition of organic vapours present in the atmosphere can occur. Before start of the reaction it is a standard procedure to replace the water by organic solvents but care should be taken to exclude oxygen. Often alcohol is used. The water is decanted and the wet catalyst is washed repeatedly with alcohol. After several washes with absolute alcohol the last traces of water are removed. 

Patient is repeatedly wetted down by sponging or spraying the skin with tepid water while a fan is blowing air across the body service... 

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