Nondestructive detection of mango pulp weevil (Stemochetus frigidus) using ultrasonic technique

Abstract

Historically, nondestructive testing has been used almost exclusively for detecting macroscopic discontinuities in structures after they have been in service for some time. It has become increasingly evident that it is practical and cost effective to expand the role of nondestructive testing to include all aspects of material production and application.
Ultrasonic techniques play a prominent role in these developments because they afford useful and versatile methods for detecting microscopic and macroscopic discontinuities in solid materials. An ultrasonic wave propagating through a solid body can be used to measure material properties and property alterations throughout the volume of an object. An ultrasonic wave, propagating from a transducer to a test object and back, crosses several interfaces with different acoustic impedances. The mismatch of the acoustic impedances causes a loss of energy due to reflections, which can be very high if air is present in the wave path. This principle of ultrasonic wave propagation makes it useful for nondestructive testing.
Although most practical uses of ultrasonics are applied to solid materials with real crystalline solids and composites, ultrasonic techniques have already been used quite successfully for evaluating internal quality of fruits and vegetables. This study aims to nondestructively detect the presence of mango pulp weevil (Stemochetus frigidus) that continues to infest the mangoes of Palawan.