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Cleaning ultrasonic

The transducers are typically mounted on an outside wall of the cleaning tank, but may also be mounted on the inside of the tank below the solution level in a sealed container. Alkaline cleaning solutions are typically at the same concentration and temperature as for a normal immersion cleaner, but the time required to clean may be less because of the ultrasonic effect. Like electrocleaning, ultrasonic cleaning produces an extremely clean surface. The main drawback is the relatively high cost. [Pg.220]

Analysis of coatings is simplified if the coating can be removed from the paper in a water bath by ultrasonic cleaning. If fibers are not present, a carbohydrate deterrnination can be used to identify gums and other carbohydrate polymers in the coating. [Pg.11]

Ultrasonic cleaning (all grades). An ultrasonic cleaner suitable for cleaning wire rope is permitted in lieu of the acid cleaning methods described previously. [Pg.593]

Deep-bed condensate polishers are commonly used for nuclear reactor power plants. Due to the extreme operating conditions, the resin is sometimes taken out of service as frequently as every 3 weeks for ultrasonic cleaning. This process removes the iron oxides and other particulates filtered out by the resin media. [Pg.381]

Owing to the widespread use of ultrasonic cleaning baths, it is not surprising that many early sonochemical experiments were directed at reactions where dirty metal surfaces were thought to be the cause of inefficiencies. Reactions typified by Grignard and Simmons Smith reactions (Scheme 7.11) are often not predictable, sometimes having long induction periods followed by violent exotherms. Frequently, small... [Pg.227]

An example of enhancement in mass transfer by acoustic cavitation is the increase in the limiting current density in electrolysis [79], The electrochemistry with ultrasound is called sonoelectrochemistry. Another example is ultrasonic cleaning [80], Soluble contaminants on a solid surface dissolve into the liquid faster with acoustic cavitation. Insoluble contaminants are also removed from a solid surface with ultrasound. This is also induced by acoustic cavitation in many cases, but in some other cases it is by acoustic streaming [81-85],... [Pg.20]

Hacias KJ, Cormier GJ, Nourie SM, Kubel EJ (1997) Guide to acid, alkaline, emulsion, and ultrasonic cleaning. ASM International, Materials Park... [Pg.28]

Figure 5.5 shows the changes in the concentration of Au(III) at different ultrasound intensities [29], where the intensities are determined by the calorimetric method. It can be seen that the concentration of Au(HI) decreases with increasing irradiation time and the reduction behavior is clearly dependent on the ultrasound intensities. At more than 1.20 W cm-2, the reduction of Au(III) was completely finished within the 20 min irradiation. On the other hand, it was also observed that no reduction occurred in a conventional ultrasonic cleaning bath (Honda Electric Co., W-113, 28 kHz, 100 W, bath-volume ca. 2 L) [29]. [Pg.137]

In the preceding chapters many aspects of sonochemistry and its application have already been discussed in details and now to conclude, few experiments are being discussed here to make the beginners in the field of sonochemistry, especially the undergraduate students, to ride on the sound wave and begin their journey of sonochemistry with some of these experiments, which can be conveniently carried out with an ultrasonic cleaning bath (Fig. 15.1) or an ultrasonic probe (Fig. 15.2) of 20 kHz, available commercially abundantly. [Pg.382]

Procedure Switch on the ultrasonic cleaning tank filled with water and watch for the position of cavitation activity through the circular rings formed on the surface of water. Hold the Al-foil on the circular ring for 2-3 min and remove. Watch the foil against the light or through an overhead projector for the holes created on it as a result of cavitation. [Pg.383]

Reason Initial fast reaction of Zn metal with acid decreases due to a thin oxide coating on the surface of the metal, hindering the further intimate contact of metal with acid. However, when the solution flask was immersed in the ultrasonic cleaning bath, the surface of the metal is cleaned by the agitation generated due to mechanical vibration and acoustic cavitation, exposing the fresh metal surface for reaction with the acid. As a secondary effect of ultrasound, the H2 gas bubbles... [Pg.383]

Procedure 10% aqueous solution of potassium iodide, KI, when exposed to sunlight, liberated I2 due to the photolytic decomposition and gave blue colour with freshly prepared starch solution. The intensity of blue coloured complex with the starch increased many fold when the same solution was kept in the ultrasonic cleaning bath. As an extension of the experiment, the photochemical decomposition of KI could be seen to be increasing in the presence of a photocatalyst, Ti02, showing an additive effect of sonication and photocatalysis (sono-photocatalysis) However, the addition of different rare earth ions affect the process differently due to the different number of electrons in their valence shells. [Pg.391]

Fig. 7. The impingement of this jet can create a localized erosion (and even melting) responsible for surface pitting and ultrasonic cleaning (68-70). A second contribution to erosion created by cavitation involves the impact of shock waves generated by cavitational collapse. The magnitude of such shock waves can be as high as 104 atmospheres, which will easily produce plastic deformation of malleable metals (77). The relative magnitudes of these two effects depends heavily on the specific system under consideration. Fig. 7. The impingement of this jet can create a localized erosion (and even melting) responsible for surface pitting and ultrasonic cleaning (68-70). A second contribution to erosion created by cavitation involves the impact of shock waves generated by cavitational collapse. The magnitude of such shock waves can be as high as 104 atmospheres, which will easily produce plastic deformation of malleable metals (77). The relative magnitudes of these two effects depends heavily on the specific system under consideration.
The ultrasonic cleaning bath is clearly the most accessible source of laboratory ultrasound and has been used successfully for a variety of liquid-solid heterogeneous sonochemical studies. There are, however, several potential drawbacks to its use. There is no means of control of the acoustic intensity, which will vary from bath to bath and over the lifetime of a single cleaning bath. In addition, their acoustic frequencies are not well controlled and differ from one manufacturer to another, and reproducibility from one bath to another may therefore suffer. Reproducible positioning of the reaction flask in the bath is critical, since standing waves... [Pg.84]

The sonochemistry of the other alkali metals is less explored. The use of ultrasound to produce colloidal Na has early origins and was found to greatly facilitate the production of the radical anion salt of 5,6-benzo-quinoline (225) and to give higher yields with greater control in the synthesis of phenylsodium (226). In addition, the use of an ultrasonic cleaning bath to promote the formation of other aromatic radical anions from chunk Na in undried solvents has been reported (227). Luche has recently studied the ultrasonic dispersion of potassium in toluene or xylene and its use for the cyclization of a, o-difunctionalized alkanes and for other reactions (228). [Pg.107]

Another recent application to the activation of transition metals was reported (247) by Bonnemann, Bogdavovic, and co-workers, in which an extremely reactive Mg species was used to reduce metal salts in the presence of cyclopentadiene, 1,5-cyclo-octadiene, and other ligands to form their metal complexes. The reactive Mg species, characterized as Mg(THF)3 (anthracene), was produced from Mg powder in THF solutions containing a catalytic amount of anthracene by use of an ultrasonic cleaning bath. A plausible scheme for this reaction has been suggested ... [Pg.110]

The ultrasonic cleaning bath is the most common source of ultrasound in the laboratory and was the equipment used in most of our investigations. The acoustic intensity is far less than the immersion horn but the low price, less than 200 for a 4" x 9 bath that holds flasks up to 1 liter in size, compared to nearly 2000 for a modest horn setup probably accounts for the difference in popularity. [Pg.223]


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