The influence of higher harmonics in electric circuits on the accuracy of current and voltage measurements in the context of the correct operation of energy protection Maintaining the movement of technological lines requires precision in the range of the most accurate measurements of parameters related to the direct use of power devices. In this context, it is important to use appropriate measuring instruments, and hence - appropriate selection of the accuracy class of the instrument and precise determination of measurement errors. Based on calculations and laboratory measurements, the authors of the article analyze measurement errors resulting from the occurrence of higher harmonics in electrical circuits.
Overview of technologies for obtaining methane from pristine coal seams - in the Polish context The article describes technologies for methane exploitation from virgin coal seams, including permeability stimulation methods and deposit availability models, against the background of the GZW geological structure and the conditions of deposit engineering of gas release from coal. It also presents the results of their current use in Poland. The article describes technologies for methane exploitation from virgin coal seams, including permeability stimulation methods and deposit availability models, against the background of the GZW geological structure and the conditions of deposit engineering for the release of gases from coal. It also presents the results of their current use in Poland.
Measurement methods for the evaluation of the threat of seismic shocks in underground mines The article discusses currently applied measurement methods for assessing the threat of seismic shocks in underground mines. The special usefulness of the so-called "invasive" methods in which the measurement system is located within the shock-absorbing zones (floor layers). A common discriminant of the interpretation results of these measurements are the volume changes of the rock mass and the structure of the rock center. Most shocks occur after the anomalous growth of the volume of the roof rock mass. The pre-shaking high energy deformation process of the rock mass takes a few dozen days and occurs on a relatively large surface / volume.Thus, the aforementioned spatio-temporal frames of this process create favorable conditions for its monitoring from a further distance, provided that properly selected and sensitive measurement methods are used.
Safety of working platforms The article concerns the safety of working platforms.Platforms of this type are used for various works performed both at heights and in mining shafts are always a threat to the safety of people staying on them.Proper design of these facilities and the development of rules for their correct operation is a key aspect of their safety.The article was created on the basis of an expert report to determine the causes of the accident of a work platform, as a result of which four employees serving the platform died.
Polish spa and healing raw materials in a market economy