Electrical devices comprised of nanoscopic wires are described, along with methods of their manufacture and use. The positive collector layer is set to have a low dose amount and set shallow so that a low injection efficiency emitter structure is realized. The controller controls a gas volume input to the glue conduit. Each of the location features is processed with at least one classifier from an ensemble of classifiers. Condensed water created at the evaporator is discharged and fed to a sensor, which determines a parameter of the condensed water, and which, from a change or a certain value of the measured parameter, draws a conclusion regarding a change of the state of the air filter.