Ultrasonic Technology

of Volume 2.- V - Aerosol Production.- 1 - Acoustic Atomization of Liquids.- 2 - Atomization of a Liquid in a Layer.- 1. Kinetics of the Process.- 2. Aerosol Characteristics.- 3. Intensity of Acoustic Atomization.- 3 - Atomization of a Liquid in a Fountain.- 1. Kinetics of the Process.- 2. Characteristics of the Aerosol.- 3. Intensity of Acoustic Atomization.- 4. Influence of Static Pressure on the Ultrasonic Formation of a Liquid Fountain.- 4 - Physical Mechanism of the Atomization Process.- 1. General Considerations.- 2. The Faraday Effect and Ejection of Droplets from the Surface of a Liquid.- 3. Atomization of a Liquid in a Layer.- 4. Atomization of a Liquid in a Fountain.- 5. Atomization Rate in a Layer.- 5 - Energy Aspects of the Acoustic Atomization of a Liquid.- 1. General Considerations.- 2. Atomization of a Liquid in a Layer.- 3. Atomization of a Liquid in a Fountain.- 6 - Prospects for the Industrial Utilization of Acoustic Atomization.- 1. Atomization of a Liquid in a Fountain.- 2. Atomization of a Liquid in a Layer.- 3. Atomization of a Liquid with the Delivery of Acoustic Energy to the Working Zone through the Gaseous Medium.- Literature Cited.- VI- The Free-Gas Content of Liquids and Methods For Measuring IT.- 1 - Determination of the Number of Bubbles and Their Sizes from the Sound Attenuation Induced by Them.- 1. Sound Attenuation in a Liquid Containing Bubbles.- 2. Apparatus.- 2 - Determination of the Free-Gas Content from the Velocity of Sound in a Liquid.- 1. Compressibility of the Liquid-Gas Bubble Medium and the Velocity of Sound in It.- 2. Apparatus.- 3 - Investigations of the Free-Gas Content of Liquids.- 1. Influence of Certain Factors on the Free-Gas Content of a Liquid.- 2. Free-Gas Content of Water in Closed Hydrodynamic Equipment.- 3. Influence of Vortex Formation in a Liquid on Its Free-Gas Content.- 4. Free-Gas Content of Ships' Wakes.- 5. Distribution of Free-Gas Bubbles in Water.- 6. Influence of Solid Impurities on the Stabilization of Gas Bubbles in Liquids.- Literature Cited.- VII-Crystallization of Metals.- 1 - Mechanism of the Crystallization of Metals in an Ultrasonic Field.- 1. Structural Changes Observed in the Crystallization of Metals in an Ultrasonic Field.- 2. Some Notions Regarding the Crystallization of Metals.- 3. Factors of the Ultrasonic Field that Affect the Crystallization of Metals and Alloys.- 4. Role of Cavitation Effects in the Formation of Finely Granular Structure.- 5. Influence of Viscous Friction Forces on the Nucleation Rate of the Crystallization Centers and Dispersion of the Crystals.- 6. Nucleation of Crystallization Centers in an Ultrasonic Field.- 7. Dispersion of Crystals in an Ultrasonic Field.- 8. Influence of Crystallization Conditions on the Ultrasonic Tractability of Materials.- 9. Insoluble Impurities in the Crystallization of Metals in an Ultrasonic Field.- 2 - Ultrasonic Treatment of Steels and Alloys.- 1. Carbon and Low-Alloy Steels.- 2. Steels of the Ferrite Class.- 3. Steels of the Austenite Class.- 4. Steels of the Carbide Class and Boron Steels.- 5. Nonferrous Metal-Base Alloys.- 3 - Technological Principles of the Ultrasonic Treatment of a Crystallizing Melt.- 1. Methods for the Ultrasonic Treatment of Melts.- 2. Transmission of Ultrasound into the Lower Part of the Melt during Crystallization of the Ingot in a Mold.- 3. Transmission of Ultrasound into the Upper Part of the Melt during Crystallization in a Mold.- 4. Ultrasonic Treatment of the Crystallization Ingot in an Intermediate Volume.- 5. Transmission of Ultrasound into the Upper Part of the Melt during Continuous Pouring.- 6. Transmission of Ultrasound through the Seed Crystal in Vacuum Arc Melting and Electroslag Melting.- 7. Formation of Gaseous Porosity.- 8. Energy Aspects of the Ultrasonic Treatment of Melts.- 9. Vibration Regime of a Waveguide Heated at the End by the Melt.- 10. Semi-Industrial Equipment.- Literature Cited.- VIII - Diffusion in Heterogeneous Systems.- 1 - The Action of Ultrasonic Vibrations on the Diffusion Process.- 1. General Remarks on the Diffusion Kinetics in Liquids and Gases.- 2. Increase of the Diffusion Coefficient in a Sound Field.- 3. Influence of Sound on the Diffusion Flow.- 4. Influence of Ultrasonic Vibrations on the Diffusion Process in a Gas and Liquid for Normal Wave Incidence on a Plane.- 5. Influence of Ultrasound on the Diffusion of a Gas from a Liquid into a Bubble in Acoustic Degassing.- 6. Diffusion through Porous Walls in a Sound Field.- 7. On the Applicability of Acoustic Vibrations for the Acceleration of Diffusion Processes.- 2 - Acceleration of Electrochemical Conversions by Ultrasonic Vibrations.- 1. Behavior of the Cathode Potential in a Sound Field.- 2. The Cathode Current in a Sound Field.- 3. Behavior of the Cathode in a Sound Field under the Conditions of Gas Liberation.- 4. Electrode Liberation of Gas in a Sound Field.- 5. Some Practical Inferences Relevant to the Deposition of Metals in an Ultrasonic Field.- 6. Action of a Sound Field on the Deposition Passivation of Cathodic Processes.- 7. Anodic Processes in a Sound Field.- 8. Dissolution, Corrosion, and Passivation of Metals in an Ultrasonic Field.- 3 - The Development of an Exposed Photographic Layer in an Ultrasonic Field.- 1. General Considerations Regarding the Kinetics of Photographic Development.- 2. Role of the Film-Binding Agent in the Acceleration of the Development Process.- 3. Development of the Photographic Layer in a Sound Field and in a Steady Flow.- 4. Role of the Photographic Exposure.- 5. Activation Energy of the Process in a Sound Field and in a Steady Flow.- 6. Mechanism of Acceleration of the Development Process in a Standing Sound Wave.- 7. Acceleration of the Development Process for Normal Incidence of an Ultrasonic Wave on the Photographic Layer.- 4 - Crystallization in an Ultrasonic Field.- 1. Linear Crystallization Rate.- 2. Kinetics of Bulk Crystallization.- 3. The Crystallization Centers.- 4. Role of Other Effects of Ultrasound in the Formation of Stable Crystallization Nuclei.- 5. Boundary-Layer Crystallization.- 6. Conclusions.- Literature Cited..- IX - Acoustic Drying.- 1 - Processes Occurring in a Wet Material during Drying.- 1. General Considerations; Affinity between Moisture and the Material.- 2. Two Drying Periods.- 3. Notions Concerning the Acoustic Drying Mechanism.- 2 - Physical Factors Affecting the Heat- and Mass-Transfer Processes in Sound Fields.- 1. Streaming in a Confined Space.- 2. Microstreaming about an Obstacle.- 3. Mechanical Effects.- 4. Variation of the Boundary-Layer Thickness.- 5. Heating of the Material.- 3 - Influence of a Sound Field on Drying in the First Period.- 1. Critical Sound Pressure Level.- 2. Evaporation from a Free Surface.- 3. Dependence of the Drying Rate on the Sound Pressure Level and Particle Velocity.- 4. Acoustic Drying Mechanism in the First Period.- 5. Influence of the Acoustic Frequency and the Size and Position of the Body on the Drying Rate.- 4 - Mechanism of the Influence of Sound on Drying in the Second Period.- 1. Influence of Sound Waves on Diffusion.- 2. Thermal Action of High-Intensity Sound Waves.- 3. Shifting of the Critical Point.- 5 - Outlook for the Industrial Application of Acoustic Drying.- 1. Drum Driers.- 2. Tunnel Driers.- 3. Fluidized-Bed Driers and Spraying Devices.- 4. Tests on the Drying of Various Materials.- 5. Drying of Finely Disperse Materials.- 6. Combination Drying Methods Using Acoustic Energy.- Literature Cited.- X - Aerosol Coagulation.- 1 - Types of Aerosol Coagulation.- 2 - Action of a Sound Field on Aerosol Particles.- 1. Entrainment of Aerosol Particles in a Sound Field.- 2. Acoustic Radiation Pressure.- 3. Aerosol Particle Drift.- 4. Hydrodynamic Forces.- 5. Other Hypotheses on the Nature of Acoustic Coagulation.- 3 - Experimental Studies of Acoustic Aerosol Coagulation.- 1. General Principles of the Coagulation Process.- 2. Elementary Aerosol Particle Interaction Events in a Sound Field.- 3. High-Speed Motion Picture Studies of Aerosol Particle Interaction.- 4 - Streaming Mechanism of Particle Interaction in a Sound Field.- 1. Role of Microstreaming in the Process of Particle Interaction in a Sound Field.- 2. Convergence and Capture of Particles in a Sound Field.- 3. Precipitation of Particles and Aggregates.- 5 - Industrial Applications of Acoustic Aerosol Coagulation.- Literature Cited.