Density of Heavy Water
THE density of heavy water was accurately determiner oy Stokland, Ronaess and Tronstad1 rature range 10–27°. Measurements fed to 50° by Chang and Chien2, and later by Wirtz3. Recently, we have further extended the measurement up to the boiling point of heavy water.
Ionization of strong electrolytes. IX. Proton magnetic resonance in the ternary system HNO3-DNO3-H2O-D2O
Nuclear magnetic resonance (NMR) was previously established as a reliable method for the determination of the degree of dissociation. The proton magnetic resonance shift has been measured in the full range of the ternary system HNO3—DNO3—H2O—D2O. The two nitric acids are about equally strong at 32°C, but at 0° deuteronitric acid is weaker, at 63° stronger than HNO3.
Velocity moments in alongshore bottom stress parameterizations
The time-averaged alongshore bottom stress is an important component of nearshore circulation models. In a widely accepted formulation the bottom stress is proportional to , the time average of the product of the instantaneous velocity magnitude |u→| and the instantaneous alongshore velocity component υ. Both mean and fluctuating (owing to random, directionally spread waves) velocities contribute to . Direct estimation of requires a more detailed specification of the velocity field than is usually available, so the term is parameterized. Here direct estimates of based on time series of near-bottom currents observed between the shoreline and 8-m water depth are used to test the accuracy of parameterizations. Common parameterizations that are linear in the mean alongshore current significantly underestimate for moderately strong alongshore currents, resulting in overestimation of a drag coefficient determined by fitting modeled (with a linearized bottom stress) to observed alongshore currents. A parameterization based on a joint-Gaussian velocity field with the observed velocity statistics gives excellent overall agreement with the directly estimated and allows analytic investigation of the statistical properties of the velocity field that govern . Except for the weakest flows, depends strongly on the mean alongshore current and the total velocity variance but depends only weakly on the mean wave angle, wave directional spread, and mean cross-shore current. Several other nonlinear parameterizations of are shown to be more accurate than the linear parameterizations and are adequate for many modeling purposes.