Acoustic transmission techniques in the development of porosity and osteoporosis measurement systems

A review of the current methods for testing for osteoporosis has been carried out, followed by porosity, to evaluate their strengths and weaknesses, and show how a new low-cost testing method could benefit the early onset detection of osteoporosis. The method has then been derived from a review of stress wave testing methods, which are primarily used to detect damage to trees or structures, measuring differences in the speed of sound transmission through impulse or impact, as well as the resonant frequency of the sample (among other properties). Measurement methods are described that can be used to detect a change in the speed of sound transmission caused by changes to porosity within a wooden dowel sample. A shaker and force transducer were first used to generate and measure a force applied transversally (perpendicular to the surface) to a solid sample, the transmitted wave was then captured by measuring acceleration on the surface of sample a set distance away from the impulse. Results showed that when the porosity was increased by drilling, the speed of sound was reduced. Attachment via a screw meant that this method would be destructive to the sample, and so the shaker was replaced by an impact hammer. A National Instruments LabView system has been used to acquire the signals using a USB oscilloscope, reliably calculate the speed of sound transmission, and save the data to file. Results for measurements taken with the impact hammer showed that an increase in porosity causes a reduction to the speed of sound transmission, with an average change of -19.12±5.68m/s per 1% increase in the porosity of a pine wood sample, and a t-stat p-value of