Sonic Systems

Protein concentration can be determined using a method introduced by Bradford,4 which utilises Pierce reagent 23200 (Piece Chemical Company, Rockford, IL, USA) in combination with an acidic Coomassie Brilliant Blue G-250 solution to absorb at 595 nm when the reagent binds to the protein. A 20 mg/1 bovine serum albumin (Piece Chemical Company, Rockford, IL, USA) solution will be used to prepare a standard calibration curve for determination of protein concentration. The sample for analysis of SCP is initially homogenised or vibrated in a sonic system to break down the cell walls. 

Dahlem O, Demaiffe V, Halloin V, Reisse J (1998) Direct sonication system suitable for medium scale sonochemical reactors. AIChE J 44 2724-2730... 

Wayment DG, Casadonte DJ (2002) Design and calibration of a single-transducer variable-frequency sonication system. Ultrason Sonochem 9 189-195... 

The sonochemical reduction of Au(III) has been investigated under Ar in the presence of 20 mM 1-propanol at different frequencies, where two types of ultrasound irradiation systems were used one is a horn type sonicator (Branson 450-D, frequency 20 kHz, diameter of Ti tip 19 mm) and the other is a standing wave sonication system with a series of transducers operating at different ultrasound frequencies (L-3 Communication ELAK Nautik GmbH, frequency 213, 358, 647, and 1,062 kHz, diameter of oscillator 55mm) [33]. All experiments were performed at a constant ultrasound intensity ((0.1+/—0.01 W mL-1), which was determined by calorimetry. 

The two main types of electromechanical transducers are based on either the piezoelectric or the magnetostrictive effect. The more commonly used of which are piezoelectric transducers, generally employed to power the bath and probe type sonicator systems. Although more expensive than mechanical transducers, electromechanical transducers are by far the most versatile and widely used. 

J. Perkins Sonic Systems Marlborough Wiltshire United Kingdom... 

For these studies, standard MRI scanners can be used to target the brain structures and to verify the BBBD. The only requirements are that the system has adequate space for the sonication system and high enough resolution to image animal brain. 

Place the animal on its back on the sonication system such that the top of the head is in the middle of the imaging coil over the window for the ultrasound beam. 

Inject degassed water under the head to couple the head to the plastic membrane of the sonication system. 

Cup horn (B in Fig. 1.8), which constitutes a special type of ultrasonic bath where the energy is supplied by an inverted horn sealed into the bottom of a water jacket or cup. This allows better temperature control of the sonicated system and of power, at the expense of a limited cell volume and reduced power relative to a standard. 

The type of sonic system used (particularly its power and frequency) and the chemical reactor (its size and geometry). 

Oxidation of iodide to iodine (Eo = -0.615 V) promoted by sonication was one of the earliest tests demonstrating the sonochemical effects on solutions. The following effects were detected in water-sonicated systems with and without CCI4 and (or) iodide ... 

Usually, the sonicator system allows adjustment of the sonication interval, the radiation amplitude and its continuous or intermittent functioning. The optimum values of these three variables depend directly on the particular analyte to be leached and the type of matrix that contains it. 

Scheme 1. Positions for the measurements of ultrasonic power in a typical sonication system.

Especially devised calorimeters can be used to calibrate transducers or check how a sonic system (generator and transducer) works. For a given power setting at the generator, the transmitted power in a sonicated medium depends on the acoustic load, i.e. on the nature of the sonicated medium and on the shape and size of the vessel. 

In order to measure the actual transmitted power Wt into the sonicated medium, many different methods have been devised. Since these methods are based on measuring changes in different parameters of the system, both physical and chemical, such methods may not be directly comparable. The decision as to which of these methods is the most accurate really depends upon which is the best adapted to the sonication system under study in terms of both the ultrasonic device employed and the application. 

The pulse cavitation peak phenomenon, where under an appropriate choice of the pulse width the cavitation yield reached an apparently maximum value, was first studied in a reverberating field [84,85], Frequencies of823-kHz and 1,7-MHz ultrasonic waves modulated by rectangular wave with an on off ratio of 1 1 and pulse width from 100 ps to 270 s were used to irradiate both an aqueous terephtha-late solution and deionized water, respectively. After sonication, the fluorescence and electroconductivity changes of the samples were measured. All the experimental data showed that a maximum value of cavitation yield occurred in the pulse width range between 10 and 100 ms. The theoretical result predicted by the authors based on the sonicated system resonance with the modulation envelope appeared to be in agreement with experimental data. In further investigations a similar phenomenon was observed for the 1.7-MHz ultrasound modulated by sine wave [86,87],... 

Skomorokhov and workers have studied the effect of ultrasound upon electrolytic boronizing processes [100] and found that the sonicated system produced metal with a smoother finish which was also considerably harder. 

The figure of merit for a sonic system of measurement that utilizes the generation, transmission, and reception of sound is defined as the maximum allowable transmission loss. This loss is derived from the sonar equation, which simply states that the received signal is equal to the background noise plus a measurement requirement, where the measurement requirement is set by the particular measurement under consideration. This method is not unique to sonics and may be applied to radar, astronomy, and communication theory. The advantage of the sonar equation that underlies the figure-of-merit computation is the fact that it permits quantitative comparison of various measurement schemes... 

Pressure in the gas portion of the sonicated system, atm. Pressure pulse, atm. 

Using hydrogen peroxide (H2O2) [<0.1%] as an advanced oxidant to the sonication system resulted in negligible inqnovement over the ultrasonic system performance conducted in the absence of H2O2. 

Emulsions containing 5 wt % TRS 10-410, 3 wt % isobutanol, sodium chloride (X %), water and equal volume of dodecane oil were prepared by sonication and by hand-shaking. The coalescence behavior of emulsions was studied for hand-shaken as well as sonicated systems. In general, sonicated emulsions required a longer time for phase separation as compared to hand-shaken systems. It was observed that for both the cases, the coalescence rate at room temperature (25°C) was maximum at the optimal salinity (1.5% NaCl) while interfacial tension was minimum at this salinity. 

Separation behavior of emulsions hand-shaken versus sonicated systems For the different aqueous to oil ratio systems considered presently, the general trend in the settling curves (volume of phase separated versus time) remains essentially the... 

Perkins, J.P. (Sonic Systems, Monks Dairy, Isle Brewer, Taunton, Somerset) personal communication. 

When the plates are close together, the attenuation of the sound is minimal (Fig. 11) and the "rules" followed in regular sonicated systems (baths, cup horns) involving large volumes and standing wave patterns are not valid in this case. 

A calibration device is usually incorporated in sonic systems to compensate for different propagation characteristics of the liquids. One of the simpler methods makes use of a... 

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