Instrumentation for ultrasonic velocity and attenuation measurements in liquids and solids is described. 5 MHz pulse generator is assembled using CMOS integrated circuits (4011, 7414, 74121, and 4010), having pulse width 2 microseconds to 60 microseconds. The wideband receiver is developed using Wideband Low Distortion, High Gain Operational Amplifier (OPA 643). The gain and bandwidth of the re...

The ultrasonic propagation in the water-based magnetic fluid with doubled layered surfactant shell was studied. The measurements were carried out both in the presence as well as in the absence of the external magnetic field. The thickness of the surfactant shell was evaluated by comparing the mean size of magnetic grain extracted from magnetization curve with the mean hydrodynamic diameter obta...

Small vibrations are simultaneously measured at two adjacent points on the aortic wall near the aortic valve by electronically alternating the directions of the ultrasonic beam. The transit delay time of the pulse wave between these two points is determined from two vibration signals obtained by this alternation beam method. The local pulse wave velocity at several millimeters on the aorta is p...

Direct ultrasonic velocity measurements have been made in fresh eollagen threads from mammalian tendon at a frequency of 100 MHz using the scanning laser acoustic microscope. Tendon is of interest since it contains an unusually large amount of collagen, a structural protein thought to be important to the echographic visualizability of normal and pathologic tissues in medical ultrasound. Results...

Ultrasonic impedance has directly been measured for various binary mixtures using a novel experimental technique. The mixtures are dimethyl sulphoxide with benzene, carbon tetrachloride and methanol at 295 K in different mole fraction ratios. The acoustic impedance of binary mixtures thus obtained was found to be in good agreement with those calculated from experimentally measured ultrasonic ve...

The acoustic properties of aqueous solutions of dextran are characterized in the frequency range of 70-400 MHz by the bio-ultrasonic spectroscopy system using an ultrasonic transmission comparison method. The attenuation, velocity, impedance, and density of aqueous dextran solutions, for six molecular weights in the range of 10,400-2,000,000 Da in the concentration range 520% by weight, are rep...