Lecture 9

chichi's version from 2018-02-27 07:35

Section 1

Question Answer
human hearing16 Hz-18 kHz
conventional power ultrasound20 kHz-100 kHz
extended range for sonochemistry20 kHz-2MHz
Diagnostic ultrasound5MHz-10MHz

Section 2

Question Answer
Applications of Ultrasound include...Engineering, Industrial, Medicine, Plastic and Polymers
Engineering Applications of UltrasoundAssist drilling, grinding, cutting. Processing glass and ceramics. Welding (plastics/metals). Dentistry
Industrial Applications of UltrasoundDispering pigments and solids in paint, inks, resins. Cleaning and degreasing materials. Acoustic filtration, drying, atomization, precipitation, degassing, electroplating
Medince Applications of UltrasoudnUltrasonic imaging (2-10 MHz). Physiotherapy; treatment of muscle strains
Plastics and Polymer Applications of UltrasoundRadical polymerization initiation. Welding of thermoplastics. Degradation of preformed plastics

Section 3

Question Answer
Sonochemistrydervives principally from acoustic cavitations: the formation, growth, and implosive collaspe of bubbles in a liquid
Bubble core Gasrous region of cavitation bubbleformation of radicals/excited molecules
Bubble vicinity gas-liquid transition regionpressure/temperature gradient, electrical fields, jets/shock waves on to metal/solid surfaces or other phase boundaries
Bulk solution bulk liquid phasesolids or solute reactants, expelled reactive intermediates

Section 4

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