Ultrasound energy

It is non-destructive - the ultrasound energy originates from within the process. 

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. 

As ultrasound energy penetrates the body tissues, biological effects can be expected to occur if the tissues absorb the energy. The absorption coefficient (a) is used as a measure of the absorption in various tissues. For an ultrasound consisting of longitudinal waves with perpendicular incidence on homogeneous tissues, the following equation applies ... 

To transfer ultrasound energy to the body, a coupling medium is required to overcome the high impedance of air. The many types of coupling medium currently available for ultrasound transmission can be broadly classified as oils, water oil emulsions, aqueous gels, and ointments. 

Ultrasound energy has also been used to accelerate the leaching of metal proteins (particularly metallothionein-isoforms and superoxide dismutase from liver samples) [103]. One of the main problems encountered in analysing these samples (namely, the need to preserve the species stability during leaching) is circumvented by USAL. 

Uitrasound irradiation of an edibie oii (particuiariy direct irradiation of the sample) causes fast oxidation of biophenois present and produces a rancid smell as a result, mainly with easiiy oxidized oiis such as those from sunfiower [73]. Ultrasound energy allows Rancimat times from 129 h to be reduced to 50 min therefore, the overall time required for the determination of oil stability, even for highly stable virgin olive oils, is less than 1 h. 

Ultrasound-based detection techniques constitute a broad group of techniques that use ultrasound energy to interrogate and measure the response of a given specimen or only as interrogating force. These techniques have been named according to the way US is... 

In a recent systematic study of the dependence of 20 kHz sonophoresis on ultrasound parameters, Mitragotri et al. showed that the enhancement of skin permeability varies linearly with ultrasound intensity and ultrasound on-time (for pulsed ultrasound, ultrasound on-time equals the product of total ultrasound application time and duty cycle), while is independent of the ultrasound duty cycle. Based on those findings, fhe authors reported that there is a threshold energy dose for ultrasound induced transdermal drug transport. Once the threshold value is crossed, the enhancement of skin permeability varies linearly with the ultrasound energy dose (J/cm ), which is calculated as the product of ultrasound intensity and ultrasound on-time. This result indicates that ultrasound energy dose can be used as a predictor of the effect of 20 kHz sonophoresis. The authors also indicated that it is important to determine the threshold energy dose for each individual sonophoresis system, for example, the real in vivo situation, because it may vary from system to system. Specifically, it may vary between different skin models, as well as with the ultrasound frequency and the distance of the transducer from the skin surface, etc. 

Application of ultrasound enhances transdermal drug transport, a phenomenon referred to as sonophoresis. Proper choice of ultrasound parameters including ultrasound energy dose, frequency, intensity, pulse length, and distance of transducer from the skin is... 

Sonication Use of ultrasound energy to agitate the plastic, releasing additives. (7)... 

Most recently, low-intensity ultrasound has been used to enhance gene transfection by liposome.139 In this study, ultrasound exposure (1 MHz, 0.4 W/cm2) for 60 seconds enhanced transfection of naked or liposome-complexed luciferase reporter plasmid into cultured porcine vascular smooth muscle and endothelial cells. These results with liposome-complexed reporter plasmid are similar to those of Unger et al., who showed that relatively low levels of ultrasound energy (0.5 W/ cm2) enhanced gene expression.140 In these two studies, ultrasound exposure did... 

Ultrasonic reclaiming of NR was reported by Okuda and Hatano in 1987, which was also patented. They subjected the NR vulcanizate to 50 kHz ultrasonic energy for 20 min to achieve devulcanization followed by revulcanization and obtained reclaimed rubber with similar properties to those of original rubber. Isayev and coworkers reported in a number of publications the phenomenon of devulcanization by ultrasound energy and they also patented their developments. ... 

It has been proposed that the absorption of ultrasound energy depends on the thermo-elastic relaxation of ice crystals in food and is affected by ice crystal orientation and size, impurities present in the ice crystals, as well as temperature (Kissam et al., 1981). Miles and Shore (1978) and Shore et al. (1986) found that ultrasound was more attenuated in frozen meats than in unfrozen tissues and that the attenuation increased markedly with temperature, reaching the maximum near the initial freezing points of the foods before decreasing rapidly at higher temperatures, thus making ultrasound particularly suitable for the controlled thawing of foods (Miles et al., 1999 Torley and Bhandari, 2007). 

FIGURE 8.2.15 Ultrasound energy can make the skin temporarily permeable to drugs such as insulin. 

Drobinski G, Brisset D, Philippe F, Kremer D, Laurian C, Montalescot G, Thomas MD (1993) Effects of ultrasound energy on total peripheral artery occlusions initial angiographic and angioscopic results. J Interv Cardiol 6 157... 

Ultrasound technology is now being implemented in recycling used tyres and crosslinked plastics. The ultrasound energy is used to break up the three-dimensional network in the crosslinked rubbers and plastics [58]. The process consists essentially of screw extruding the heated crosslinked material onto a powerful sonicator. It was shown that high power ultrasonic waves are capable of rapidly breaking down the three-dimensional network present in crosslinked elastomers and plastics. 

---