Water jet method

Ultrasound has been successfully employed for the removal of radioactive cruds by Japanese workers [250], Radioactive crud deposited on the various apparatus of a nuclear power plant was removed by electropolishing followed by ultrasonic cleaning. Their method exhibited excellent removal efficiency, and was found to be especially useful for removing deposits on the inside wall of coolant conduits. Similar results were obtained by Gauchon et al. [251] who studied the decontamination of German BWR nuclear reactors by chemical, electrochemical, and water-jet methods employing ultrasound. Their results showed that simultaneous electrolysis and ultrasound gave the most efficient method for decontamination. 

The paint peeling methods specified in (b) are divided into a mechanical peeling method and chemical peeling method. For the mechanical peeling method, shot-blast and waterjet methods were evaluated. The shot-blast method is to spray particulate agents on a painted TP bumper surface by means of compressed air in order to peel off the paint film. The water-jet method uses high pressure water instead of particulate. Both of them are unsuitable for the treatment of such bulky products with complex geometries as bumpers. 

It was determined, for example, that the surface tension of water relaxes to its equilibrium value with a relaxation time of 0.6 msec [104]. The oscillating jet method has been useful in studying the surface tension of surfactant solutions. Figure 11-21 illustrates the usual observation that at small times the jet appears to have the surface tension of pure water. The slowness in attaining the equilibrium value may partly be due to the times required for surfactant to diffuse to the surface and partly due to chemical rate processes at the interface. See Ref. 105 for similar studies with heptanoic acid and Ref. 106 for some anomalous effects. 

In the second step, a papermaking method is also used for the fine fibers, less than 0.1 tex (1 den). This process is usually followed by a high pressure water jet process instead of the third step. In the fourth step, to obtain the required properties in specific appHcations, a polyurethane is selected out of the segmented polyurethanes, which comprises a polymer diol, a diisocyanate, and a chain extender (see Urethane polymers). A DMF—water bath for coagulation is also controlled to create the adequate pore stmcture in combination with fibers. 

In atomization, a stream of molten metal is stmck with air or water jets. The particles formed are collected, sieved, and aimealed. This is the most common commercial method in use for all powders. Reduction of iron oxides or other compounds in soHd or gaseous media gives sponge iron or hydrogen-reduced mill scale. Decomposition of Hquid or gaseous metal carbonyls (qv) (iron or nickel) yields a fine powder (see Nickel and nickel alloys). Electrolytic deposition from molten salts or solutions either gives powder direcdy, or an adherent mass that has to be mechanically comminuted. 

Usually before adding a surfactant it is necessary to clean the surface of the water solution by siphoning off the top layers of water with a glass capillary until the constant compensation voltage is obtained. This is not done in the jet method. 

OB to C02 —37.4% colorless, somewhat volatile liquid, with faint aromatic odor sp gr 1.348 at 20/4°, fr p below —20°, bp 91—2° in a vacuum of a water jet pump and decomp at atm pressure miscible with w and sol in ale, eth chlf dissolves in coned sulfuric acid with considerable evolution of beat, so that in the detn of die nitrogen concent by Nitrometer Method (See Vol 1 of Encycl, pp A373—A378)... 

If very hard materials (e.g., natural stone, or metal sheets) must be cut, the injection of abrasives into the water jet will support and accelerate the cutting procedure (see Fig. 1.4-5, bottom, right side). The water-jet cutting represents a very flexible production method which can be regarded as supplementary to LASER methods if thermal influences on the materials involved cannot be accepted. 

The inks can contain drying oil alkyds along with hydrocarbon resins and high boiling (200—370 °C) hydrocarbon solvents. Business form inks closely resemble the lithographic heatset or quickset inks. Business forms have also been printed by the ink jet method. These inks are usually based on water, glycols, and dyes. 

A method of cleaning large heat exchangers and other cooling system components with high pressure water jets (1000 -Fpsi). 

Figure 4.20. Surface potential relaxation of water and aqueous NaCl solutions. Oscillating Jet method. Temperature 24°C. The electrolyte concentration is indicated. (Redrawn from Kochurova et al.. )...

The most commonly used test for measuring water resistance is the water washout test method (ASTM D-1264, IP 215) in which a greased ball bearing is rotated at 600 rpm in an assembly with specified clearances in the covers to allow entry of water from a water jet that impinges on the face of one cover. The loss in grease pack after 1 h of operation is a measure of the resistance to water. The test serves only as a relative measure of the resistance of a grease to water washout. 

---