Use of X-ray Tomography for the Experimental Verification of a Mathematical Model for the Recovery of Cu and Cd in a Flow-By Porous Electrode Reactor.

In this work a mathematical model for a flow-by electrochemical reactor operating galvanostatically for the Cu and Cd electrodeposition and hydrogen evolution reaction (HER) has been proposed. X-ray computed tomography was used to measure experimental metallic distributions. Good agreement was found between the experimental measurements and model predictions for conversion, current efficiencies, electrode potential and metallic deposit distributions. Differences were observed between experimental results and model predictions and were attributed to a change in Cd electrodeposition and HER kinetics.

A potential environment for lasing below 15 nm initiated by exploding wire in water

Proximity wall stabilized, fast (>4 × 1011 A/s), high current (>40 kA) discharges are capable to create long, dense, hot, stable, non-equilibrium plasma column, suitable e.g., for radiation amplification or even for lasing in extreme ultraviolet and soft X-ray region. Exploding wire in water resembles a metal-vapor-filled capillary with liquid, ever fresh wall (without any metallic deposit). Modeling of wire explosion (inclusive melting and boiling phase transitions, thermal diffusion, and variable conductivity) by the originally skinned driving current is described. Modeling results are compared with measurement of the discharge current and with side-on and end-on monitoring of H-alpha line emission. Analysis of H-alpha line profile is used for diagnostic of water-vapor layer around the wire. The differences between model and reality are attributed to the fact that the pressure dependence of material constants was neglected in the first approximation.

I. On electrostriction

If the bulb of an ordinary thermometer be coated chemically with silver, and then electrically with a metallic deposit, the mercury will traverse some portion of the scale, and finally take up a definite posi­tion, independently of temperature. To this phenomenon I have given the name electrostriction . Of the metals hitherto worked with, copper, silver, iron, and nickel constrict the bulb; zinc and cadmium distend it. The general conditions under which the experiments were made were as follow:—A thermometer coated with silver by immersion in a solution of ammoniacal argentic tartrate was placed vertically near a bare ther­mometer at one side of a depositing cell; the anode stood at a distance of 11 centimetres. The bulbs of the thermometers were about their own depth below the surface of the electrolyte; the covered one was turned half round at every comparison. The source of electricity was a pint Daniell’s cell, having a porous diaphragm, and the circuit included a galvanoscope. Observations were made at definite intervals of time, imme­diately after stirring the liquid; and the difference between the two scales, after suitable reduction, was registered as electrostrictive effect. The temperature was in all cases the unrestricted temperature of the labo­ratory.