Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based capacitive humidity sensors, as well as of modelling the behaviour of that type of sensor. A logarithmic functional relationship between the relative humidity and the change of sensor output value at low humidity is suggested.

In order to work out a procedure of diminishing the amount of heavy metals, barium and strontium in wastes, laboratory wastes were collected and investigated. The analysis revealed that mercury and silver are present only in the precipitate, as well as about 213 amount of lead, bismuth and cobalt. Other elements occur mainly in solution. It was also found that there was no justification for the separate segregation of particular analytical groups of elements, especially in the cases where it is difficult to enforce requirement of collecting wastes in proper containers. Solid wastes were divided into two groups: I - containing mercury and 2 - without mercury content. Metals were eliminated in the form of sulphides and hydroxides by their precipitation with sodium sulphide, flocculation, sedimentation and dehydration. Solutions left after metals separation meet requirements for wastes, which can be disposed of the sewage system.

Is this article simulation of statistical measurements is performed on the basis of which the analysis of the standard deviation of the obtained results is carried out. It is shown that the standard deviation is minimum and independent from measurement duration while an object is in the state of equilibrium. For objects in a stationary non-equilibrium state the standard deviation depends on the duration measurements and the parameters of the state. The influence of these factors on the standard deviation is assessed with equation which includes the relaxation time. The value of the relaxation time is determined by approximating the energy spectrum of the studied signals. The analysis of energy spectra showed that the spectrum of white noise is inherent in objects in equilibrium; the flicker component of the spectrum occurs when the state of the object deviates from equilibrium.

A procedure has been proposed for proceeding with homogeneous chemicals being technical products or reagents stored in unlabelled packages, in order to classify these substances to particular categories of wastes. A series of simple tests belonging to a classical analysis of chemical compounds, complemented with instrumental methods in needed cases has been proposed. The requirements have been established for equipment and necessary qualification of personnel in a laboratory in which identification is to be carried out. Attention has been drawn to risk accompanying this procedure and necessary precautions, which should be undertaken, especially due to possible explosive, inflammable and toxic properties of these substances. The worked out procedure was verified in tests and applied during cleaning the central chemical storage rooms.