Study On Theories And Experiments Of Milk Quality Ultrasonic Measurement

Ultrasonic measurement technology, a green measurement technology has already not only applied successfully in some fields getting a world spotlight accomplishment such as life medical science ,disease diagnosing, petrochemical industry , food , environmental monitoring, material analyse, but also in the field of liquid components analyse. Ultrasonic measurement technology has prominent advantages and well development prospect in milk quality measurement, however, it hasn't satisfied production need of milk quality measurement so far. Main cause lies in the study deficiency for"milk acoustics", including the effect mechanism between ultrasonic and milk and the research of ultrasonic transmission in milk. The dissertation studied effect mechanism and measurement influencing factors of milk quality ultrasonic measurement adopting theoretical analysis and experiment research, built the acoustics model according with the actual effect process between ultrasonic and milk, resolved the theory difficult problem of milk quality ultrasonic measurement. Studied effect mechanism of milk measurement by reason of temperature change, analysed characteristic resolving temperature effect methods, brought forward the"temperature dynamic measurement principle", and studied specifically its modeling methods, resolved the application choke point of milk quality ultrasonic measurement. Concrete content is included:1) Deduced the ultrasonic sound velocity model transmitting in multiplicative liquid milk starting off three fundamental equations that ultrasonic transmitts in ideal liquid, given out the milk absorbability attenuation model to ultrasonic on the basis of Stokes absorbability theory , Kirchhoff theory and milk characteristic. The milk dispersion attenuation model was deduced from classics dispersion model, opened out the ultrasonic transmission characteristic in milk and effect mechanism between ultrasonic and milk. studied the characteristic of fattiness and protein with experiments, and validated the validity of sound velocity model and attenuation model.2) Analysed the temperature problem which is the pivotal influence factors of milk ultrasonic measurement by the numbers. Studied the mechanism because of temperature change, and confirmed its effect degree with experiments, educed that the effect to milk sound velocity and attenuation coefficient with temperature change 0.1℃corresponds to fat percentage thickness changing 0.1% or protein thickness changing 0.15% ,therefore, the temperature controlling or measurement accuracy need overtop 0.1℃in order that measurement absolute error of fat and protein is smaller than 0.1% and 0.15%, brought forward the"temperature dynamic measurement principle"in order to reduce the temperature effect to ultrasonic measurement.3) Chemistry metrology method was applied to the modeling method of milk components measurement ,partial least square linear regression arithmetic was used to establish associated model arithmetic of ultrasonic parameters, temperature and milk components. Brought forward three methods of establishing temperature calibration model in order to improve model forecasting accuracy and reduce temperature effect. Educed the best modeling method with experiments contrast research that modeling with sound velocity and attenuation coefficient, part temperature calibration method. It gets the highest forecasting precision modeling with this method, can satisfy the need of industry actual measurement.