Acoustical Driving Forces (ADF), induced by propagating waves in a homogeneous and inhomogeneous lossy fluid (suspension), are determined and compared depending on the concentration of suspended particles. Using integral equations of the scattering theory, the single particle (inclusion) ADF was calculated as the integral of the flux of the momentum density tensor components over the heterogeneity surface. The possibility of negative ADF was indicated. Originally derived, the total ADF acting on inclusions only, stochastically distributed in ambient fluid, was determined as a function of its concentration. The formula for the relative increase in ADF, resulting from increased concentration was derived. Numerical ADF calculations are presented. In experiments the streaming velocities in a blood-mimicking starch suspension (2 μm radius) in water and Bracco BR14 contrast agent (SF6 gas capsules, 1 μm radius) were measured as the function of different inclusions concentration. The source of the streaming and ADF was a plane 2 mm diameter 20 MHz ultrasonic transducer. Velocity was estimated from the averaged Doppler spectrum obtained from originally developed pulsed Doppler flowmeter. Numerical calculations of the theoretically derived formula showed very good agreement with the experimental results.

The paper is concerned with one of the internal forces driving the progress of lyrical discourse. Its nature consists in that initially, some linguistic and/or cognitive deviation appears in the poem, and next the author undertakes a series of attempts at its adjustment or mitigation. More often than not these attempts are increasingly successful, but at some later point they, for various reasons, stop to be rewarding. This tends to happen either at the end of the text, where the most important truth is prototypically discovered, or immediately before the final fragment. In both cases, the completion of the relevant ‘adjustment’ theme plays a significant compositional role. Discussed at some length are the implications of our analysis for the theory of discourse relations. The bulk of the instances under examination are drawn from O. Mandelstam’s verse.