Abstract: The extent of fouling of a spiral wound membrane module such as used in water treatment plants can be monitored using one or more sensors disposed between wraps of the membrane. The sensors, including electrodes, can communicate signals to a two-part computing device. A first part is located inside the pressure vessel in which the membrane module is disposed. The first part provides input signals and power to the sensors and receives sensor signals. A second part is located on the outside of the pressure vessel and communicates power to the first part via inductive coupling. The second part wirelessly receives the sensor signals from the first part and processes the signals to determine the extent of fouling of the membrane module.

Abstract: A method of and device for ascertaining elastic and di-electric properties f the diaphragm of individual living cells of living beings or of the diaphragms of such living cells in a physiological liquid in suspension or of such living cells in an association in the form of a layer. One or more of such cells or one or more layers of such cells is or are introduced into a physiological liquid which has a temperature of between 0.degree. and 40.degree. C and which is electrically conductive and forms an electrolyte solution. The cell, cells or layer of cells are located between two electrodes in such a way that the flow lines of an electric field provided between the two electrodes penetrate the diaphragm of the cell, cells or layer of cells introduced into the electrolyte solution. Thereupon a succession of voltage pulses with a constant pulse duration of from 1 .mu.