Alexander Kolin

Theory of Electromagnetophoresis. I. Magnetohydrodynamic Forces Experienced by Spherical and Symmetrically Oriented Cylindrical Particles

This paper is the first of a series dealing with the theory of the electromagnetokinetic effect. This effect consists of the exertion of a force upon a body submerged in a fluid which is traversed by an electric current and a transverse magnetic field. In this communication the conditions for equilibrium of an homogeneous fluid are established and forces upon particles suspended in the fluid are determined. The computations are carried out for spherical bodies and long cylindrical bodies oriented parallel to the magnetic field, to the electric current, and to the exerted force. It is shown that the effect could be observed with suspended particles which differ from the surrounding fluid in the value of their electrical conductivity or dielectric constant, and/or their magnetic permeability.

Electromagnetic Velometry. II. Elimination of the Effects of Induced Currents in Explorations of the Velocity Distribution in Axially Symmetrical Flow

The distribution of electrical potential in a conduit carrying an axially symmetrical flow through an homogeneous magnetic field, which is perpendicular to the flow, is analyzed. It is shown that it is possible to eliminate the difficulties arising from induced currents in electromagnetic determinations of the velocity distribution by measuring the potential gradient ∂ψ/∂y (y being ⊥H and ⊥v) along a diameter bisecting the angle between the H axis and the Y axis. The knowledge of the distribution of (∂ψ/∂y)45° at a known discharge through the conduit determines the velocity distribution v=f(r).

A Method for Adjustment of the Zero Setting of an Electromagnetic Flow Meter without Interruption of Flow

The paper describes a means of establishing the reference point of zero velocity for a flow meter scale without stopping the flow. This is accomplished by introducing two auxiliary electrodes which are disposed so that the voltage picked up by them is independent of the rate of flow. The method of adjustment minimizes artifacts caused by movement of the blood vessel in the magnetic field.

Calcium Oxytetracycline Complexes.∗ New Apparatus for Frog Heart Method of Estimation of Calcium Ion Concentration

Summary Calcium complexes of oxytetracycline were analyzed by the use of the frog heart method with an improved apparatus employing a vertical shutter, photoelectric transducer, bridge circuit, and recording system. This method was readily applicable to complex biologic solutions and produced results comparable to those in the preceding article obtained by spectrophotometry on pure solutions. The log K of the 1:1 calcium oxy-tetracycline complex was 3.04, compared with 3.19 for the 1:1 complex of citric acid and calcium.

Thermal convection in a uniformly heated fluid between vertical parallel plates

In methods of continuous‐flow‐deviation electrophoresis, a basic element of the apparatus is a conductive fluid sheet sandwiched between two closely spaced parallel vertical plates which are maintained at a constant temperature while the fluid is uniformly heated by an electric current flowing parallel to the plates. A horizontal temperature gradient is established with a maximum temperature in the midplane of the fluid sheet. The velocity distribution of the resulting thermal convection is calculated in two steps: (1) in the general case for plates whose separation is negligible compared to their lateral dimensions, and (2) for the physical conditions encountered in fluid‐sheet electrophoresis which justify the approximations that the effect of viscosity variations is negligible and that the density is a linear function of temperature. The resulting expression for the velocity distribution is a fourth‐order polynomial in z (distance of a point from the midplane between the plates). The function has three...