1. ACOUSTIC THEORY  WAVE VELOCITY  ACOUSTIC IMPEDANCE  REFLECTION AND TRANSMISSION  REFRACTION  RADIATION  ATTENUATION

2. Gases : Liquids : Solids : B = modulus bulk  = compressibility Y = Young modulus  = Poisson ratio  = specific heat ratio  o = mass density P p = pressure ACOUSTIC WAVE VELOCITY  Sound velocity, speed of sound (SOS)  Depend on the medium/material properties  c solid > c liquid > c gas

3. ACOUSTIC IMPEDANCE  Defined by the ratio of acoustic pressure and particle velocity  Z =  c GasTemperature [ o C] Mass Density [kg/m 3 ] Wave Velocity [m/s] Acoustic Impedance [Rayls] Air01,293331,5428 Air201,21343415 O2O2 01,43317,2512 CO 2 01,98258532 H2H2 00,091269,5114 Steam1000,6404,8242 Wave velocity and acoustic impedance in gases

4. LiquidTemperature [ o C] Mass Density [kg/m 3 Velocity [m/s] Acoustic Impedance [MRayls] Water2099814811,48 Water13102615001,54 Alcohol2079011500,91 Oil2095015401,46 Mercury2013600145019,72 Glyserin20126019802,50 Wave velocity and acoustic impedance in liquids

5. SolidVelocity [ o C] Mass Density [kg/m 3 Acoustic Impedance [MRayls] Rubber110024002,64 Plastic118026703,15 Copper8900500044,5 Steel7800585045,63 Aluminum2700630017,01 Concrete260031008,06 Wood45035001,58 Wave velocity and acoustic impedance in solids

6. REFLECTION AND TRANSMISSION PiPi PrPr PtPt First medium Z 1 Z 2 Second medium R = Reflection factor T = Transmission factor

7.  R = Power reflection coefficient  T = Power reflection coefficient Acoustic Intensity :

8. PiPi PrPr PtPt First medium Z 1 Z 2 Second Medium x ii rr tt REFRACTION Critical angle :

9.  D N Fraunhofer zoneFresnel zone WAVE RADIATION N = Near field length D = Transducer diameter = Wave length

10. ATTENUATION x IoIo I I o = Initial intensity I = Intensity after propagation  = Coefficient of attenuation