Cleaning sonic, ultrasonic

The filter bags may also be cleaned by ultrasonic vibrations. The level of sonic pressure should not be lower than 125 dB for a frequency of 200-4000 cps its precise value is determined by the construction of the filter and the properties of the adhering dust. 

Ultrasound enhanced the rate of dissolution of zinc metal in alkaline media, 2-3 times in sonicated condition rather than the unsonicated condition, due to the cleaning of metal surface in ultrasonic field. Decomposition of Zn-dithizone complex was also observed in ultrasonic field. In sonicated samples, the peak of... 

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. 

Ultrasound activation of metals. Since its discovery as an activation technique some fifty years ago, sonication has been demonstrated to be of general use for the depassivation of different metals. In this case, the activation consists in cleaning the surface of the metal, making possible better contact between the reagents. Probably the most important applications of ultrasonic irradiation are the direct preparation of organometallic reagents and different metal-assisted reactions, for instance in aqueous media . 

To a suspension of UDP (4.5 mmol) in toluene (10 ml) in a laboratory ultrasonic cleaning bath under N2 was added a solution of 2,2,5,5-tetraethyl-3-sulfolene (1.5mmol) in toluene (10ml). The sonication was continued for 30 min, during which time a bright-blue colour developed. A solution of t-BuOH in THF (0.45 mol dm"3,4.4 mmol) was added dropwise over a period of 30 min, whereupon the potassium was completely consumed. The mixture was filtered through a short silica gel column to remove the solid precipitate, and the filtrate was concentrated under reduced pressure. Purification by HPLC (Lichrosorb column, hexane) yielded the corresponding diene in a 92% yield. 

Archaeological bone samples were treated for diagenesis before sample analysis. The bone samples were first mechanically cleaned with the Patterson NC-350 dental drill equipped with a carbide burr to remove any organic matter or contaminants. The mechanical cleaning also removed the layers of cortical bone most susceptible to diagenetic contamination, as well as all traces of trabecular bone. The bone samples were then chemically cleaned in an ultrasonic bath. The samples were first sonicated in water for 30 minutes, then rinsed and sonicated in 5% acetic acid for 30 minutes, and finally rinsed and sonicated with 5% acetic acid for 5 minutes (30, 53, 55, J9).The bone samples were dried for 1 hour at approximately 80°C. Finally, the bone samples were placed in a crucible and ashed at approximately 800°C for 10 hours. 

However, this commonly accepted theory is incomplete and applies with much difficulty to systems involving nonvolatile substances. The most relevant example is metals. For a heterogeneous system, only the mechanical effects of sonic waves govern the sonochemical processes. Such an effect as agitation, or cleaning of a solid surface, has a mechanical nature. Thus, ultrasound transforms potassium into its dispersed form. This transformation accelerates electron transfer from the metal to the organic acceptor see Chapter 2. Of course, ultrasonic waves interact with the metal by their cavitational effects. 

The buffer (-800 ml) is heated to boiling in the microwave oven and poured into an 80-W ultrasonic cleaner (Bransonic 12, Branson Cleaning Equipment Co., Shelton, CT). The slide rack is sonicated for 1 min and then cooled in buffer in the staining container for an additional 10 min. 

Review.1 This review includes a discussion of the three types of ultrasonic generators whistlers, cleaning baths, and probe disruptors. The last is the most efficient, but the most expensive. Cleaning baths are inexpensive, but are limited in the temperature range to that of the liquid used, generally water. The review concludes that sonication is most useful in heterogeneous reactions, particularly those of organometallics. The references (235) date from 1953 to the present time, with most in the last 10 years. 

Pre-treatment of the electrode substrate, which involves polishing, sonicating, and rinsing. The electrode can be pohshed using diamond pastes or alumina, followed by ultrasonic cleaning in water, acetone, or ethanol, and is then rinsed to obtain a clean surface. 

Possibly, the high value added to the processed food will facilitate the implementation of non-invasive ultrasonic apparatus for the removal of fouling in food processing equipments. With this aim, an ultrasonic apparatus operating at a frequency of 40 kHz was developed for dislodging biofilms from food processing equipments in order to assess the effectiveness of cleaning protocols. The optimum sonication conditions for the removal... 

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