Microacoustic Interferometer Using 30-Mc Pulses

Abstract

In the described instrument ten-microsecond, 30-Mc carrier pulses reflected from a resonant layer allow a theoretical precision of 0.1 percent in making velocity determinations while using less than 0.1 cc of test liquid. By the same technique, ultrasonic absorption can be measured in highly dissipative liquids using layers about 0.1 mm thick. Water velocities observed at 30 Mc are presented along with values by others in the range of 0° to 93°C. V = 1554−0.0305(68.4−T)2 is proposed as the best empirical parabola to accommodate the available data, and an additional cubic correction formula is suggested.

Aqueous chemistry and thermodynamic modelling of CaO–SiO2–H2O gels

“…The free energy of formation of amorphous SiO, has been adjusted with respect to that given in ref. 20 in order to account for the relative observed solubilities of amorphous SiO, and ~ 2 3 The resulting database was then found to give acceptable agreement with experimental data for the solubility of amorphous SiO, as a function of pH and the solubility of portlandite. For example the pH and [Call for portlandite in water at 25 "C were calculated to be 12.41 and 0.0225 respectively, whereas the corresponding measured values are 12.45 and 0.0203.…”

“…Their existence has been reported in Victorian cements about 136 years old,' in ancient cements about 2 000 years old,2 and in natural formations estimated to be about 60 million years old. 3 The general term 'C-S-H gel' covers a class of solids which vary widely in composition and crystallinity. Some are relatively well defined in terms of structure and composition such as the C-S-H(1) and C-S-H(I1) gels studied by Taylor and cow o r k e r ~.…”

A Study of Speed of Sound in Water

“…The study of sound speed in water becomes still more important due to fact that it exhibits a maximum near 76 0 C. Some empirical relations [1][2][3][4] are available in literature to study the speed of sound in water as a function of temperature but no model or theory is available so far. Though, a model [5][6] is available to study the pressure dependence of speed of sound in liquids.…”