An experiment is described in which a constant stress is applied to the surface of an initially quiescent tank of fluid with a uniform density gradient. The development of the turbulent layer by entrainment of the underlying fluid is described and it is found that the entrainment coefficient E, the ratio of the entrainment velocity ue to the friction velocity u* is given in terms of the depth D of the mixed layer and the density jump δρ across the entrainment interface by the relation \[ E = \frac{u_e}{U_{*}} = 2.5\frac{\rho_0u^2_{*}}{g\delta\rho D}. \] The rate of increase of potential energy of the stratified fluid was found to be proportional to the rate of dissipation of kinetic energy per unit area in the turbulent layer. The form of these results is consistent with those found by Turner with an agitation tank, but the parameters used here allow direct application to entrainment in the ocean.

We report on the temperature dependence of electrical resistivity, Seebeck coefficient and Hall coefficient of the Fe 2 VAl 1-y Si y alloys with Si compositions y＝0 0.20. While the Heusler type Fe 2 VAl ( y＝0) exhibits a semiconductor like resistivity behavior, a slight substitution of Si for Al causes a sharp decrease in the low temperature resistivity and a large enhancement in the Seebeck coefficient. Substantial enhancements for the Seebeck coefficient are in reasonable accord with changes in the Hall coefficient and can be explained on the basis of the electronic structure, where the Fermi level shifts slightly from the center of the pseudogap due to the substitution of Si. In particular, the Si substitution of y＝0.10 leads to a large power factor of 5.4×10 -3 W/m K 2 at room temperature, which is comparable to that of conventional thermoelectric materials.

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