Re‐examination of boric acid relaxation with high‐precision spherical resonator Free

The dependence of low‐frequency sound absorption on pH as a function of $B(OH)3$ concentration in 0.725M NaCl was studied with a computer‐controlled high‐precision spherical resonator. For these measurements, a 100‐liter titanium spherical resonator was mode mapped in the frequency range of 2 to 100 kHz when containing distilled water, then 0.1M, and finally 0.725M NaCl solutions. Frequency shifts and decay rates of the radial modes were studied with the NaCl concentrations. Using a solution of boric acid equal in concentration to sea water (4.2 × 10⁻⁴ M) at pH 8.2, in 0.725M NaCl, reliable absorption measurements have been made at frequencies as low as 6 kHz. [Work partially supported by ONR.]