Air agitation

The temperature of the anodizing solution also has an effect on the anodic film stmcture. Thus chillers are used to maintain a consistent temperature in the bath while the part is being anodized, and air agitation is continuously appHed to ensure a uniform temperature. The result is a consistent anodic film density of uniform pore size. 

Preparation is accompHshed by simple blending of the diluent into the hot base asphalt. This is generally accompHshed in tanks equipped with coils for air agitation or with a mechanical stirrer or a vortex mixer. Line blending in a batch circulation system or in a continuous fashion (40) is used where the volume produced justifies the extra faciUties. A continuous, line-blending system is appHcable to the manufacture of cutback asphalts and asphalt cements (Fig. 8). 

Both cell types utilize 5—25 g/L Cr at a pH = 2.3-40 and a temperature from 20—50°C under mild air agitation. Current densities mn from 430—1600 A/m, the rectifier voltage is from 4—15 V, and the anode to cathode ratio is 2 1. 

For all baths the anode to cathode ratio is 2 1 the baths are mechanically, hydrauhcaHy, or air agitated, and there is continuous filtration. 

The most common plafing bath uses fluoride to complex the fin. A typical solution contains 45 g/L staimous chloride, 300 g/L nickel chloride hexahydrate, and 55 g/L ammonium bifluofide. It is operated at pH 2.0—2.5 usiag ammonium hydroxide temperature is 65—75°C and current about 200 A/m. The bath has excellent throwing power. Air agitation is avoided. The deposit is bright without additives. Anodes are cast nickel, and the fin is replenished by additions of staimous chloride. AHoy anodes of 72% fin have been used to a much lesser extent. Tia-nickel deposits are covered by ASTM (136) and ISO (137) specifications. One other bath based on pyrophosphate has appeared ia the Hterature, but does not seem to be ia commercial use. 

Air-agitated liquid/ liquid contactors PM M 0.05-0.3 Can he varied over a wide range 0.1-0.3 10-100 1.0-30... 

Use air agitation or workpiece agitation to improve rinse efficiency. 

RP-HPLC methods have been frequently applied for the investigation of various chemical, biochemical and biophysical processes in in vitro model systems. Thus, the separation of new compounds achieved by enzymatic oxidation of phloridzin was carried out by semi-preparative RP-HPLC. Phloridzin was incubated with a polyphenol oxidase prepared from apple pulp for 6h at 30°C under air agitation. After incubation the suspension was filtered, stabilized by NaF and injected into the RP-HPLC column using diluted acetic acid-ACN gradient. The new compounds were isolated and identified by NMR and MA techniques. The proposed mechanism of the formation of new phloridzin derivatives 3 and 4 is shown in Fig. 2.159. The results illustrate that RP-HPLC can be successfully used for the study of enzymatic processes in model systems [331],... 

Cleaning and destruction. After the precipitation has been completed, the precipitation column and suction filters should be washed thoroughly with water. For cleaning, the precipitation column is filled with water, nitric acid and sodium nitrite are added, and the air agitation is switched on for half an hour. Then the contents are discharged and the column is rinsed again with water to remove the acid. 

Figure 11.7. Two types of laboratory filter arrangements, (a) Vacuum test filter arrangement standard sizes are 0.1, 0.05, or 0.025 sqft (Dahlstrom and Silverblatt, 1977). (b) Laboratory pressure filter with a vertical filtering surface and a mechanical agitator mild air agitation may be preferred (Bosley, 1977).

The process works with carbon anodes and at a cathode current density of 10 A dm-2. The electrolyte is contained in a plastic or rubber lined bath and air agitation is required. Although a chromium complex is involved, full details of the electrolyte composition are not available in the journal paper reporting the successful development of the new process.20 Chromium is consumed as the basic sulfate and the ligand is described as inorganic. Conductivity salts are required to improve the conductivity of the solution and some boric add is present as a buffer. 

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