Processes using ultrasound

The extent of granule erosion thus depended on the nature of the atmospheric gas under which the irradiations were carried out, and it was observed that the sizes of the pits were inversely proportional to the solubility of the atmospheric gas in water. The extent of granule 

Jackson and co-workers (1988) used mild sonication conditions (20 s at 55 °C) to disrupt swollen starch granules. This treatment increased the solubility of starch in water without extensive depolymerization and allowed starch samples to be characterized by HPLC-SEC without the use of DMSO or alkaline aqueous solvent systems. Sonication for longer than 80s substantially altered the HPLC-SEC profile. 

Treatment with ultrasound has also been used to enhance the reactivity of starch with enzymes. Barton and co-workers (1996) studied the effects of ultrasound on the activities of alpha-amylase and glucoamylase toward soluble potato starch. With a-amylase, increased reaction rates were observed with sonication at low concentrations of starch (8g per liter) although at starch concentrations of 15-50g per liter, both sonicated and un-sonicated 

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Some studies have been performed on the continuous casting of aluminum alloys with UST in Japan (Furucawa Co.) and on an intensification of various metallurgical processes using ultrasound in China [27],... 

Passerini N, Peiissutti B, Moneghini M, Voinovich D, Albertini B, Cavallari C, Rodriguez L (2002) Characterization of carbamazepine-Gelucire 50/13 microparticles prepared by a spry-congealing process using ultrasounds. Journal of Pharmaceutical Sciences 91 699-707. 

Sonochemical destruction is a process for the destruction of volatile organic compounds (VOCs) in water using ultrasound. The technique is being researched for the treatment of contaminated ground and process water. Sonochemistry in liquids is the inducement of chemical reactions by the application of ultrasound energy acoustic cavitation results in the formation of hot spots of intense temperature and pressure that cause the destruction of VOCs. 

Acetonitrile, acetone, ethanol, and methanol have been used to extract isoflavones from soy foods. Among them, acetonitrile proved to be the most efficient (Griffith et al., 2001 Murphy et al., 2002). The solvent is supplemented with 0.1 M HC1 to completely un ionize the isoflavones and to release them from protein complexes by denaturing and precipitating the proteins. Room temperature is recommended for extraction to avoid alteration of the natural forms of the isoflavones. The time for extraction, 2 hr, was chosen for maximum recovery and shortest processing time. Ultrasound is used to aid the extraction process by degrading and weakening the cellular matrix. 

A similar in situ HO generation can be obtained using high power ultrasound sources or by processes using subcritical or supercritical water (at very high temperatures or pressures). [9] and other references therein and in Table 3 can be consulted. 

Surprisingly, zinc has been inserted directly into C—F bonds using ultrasound techniques, and in the presence of metal salts, e.g. SnCl2. The reactivity of the system appears to depend at least partly on the electron affinity of the aromatic system, because hexa-fluorobenzene is relatively unreactive in the process [57] (Figure 10.16). 

USING ULTRASOUND TO ASSIST VARIOUS STEPS OF THE ANALYTICAL PROCESS... 

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