The paper presents the results of investigations on resistance structures based on graphite oxide (GRO) and graphene oxide (rGO). The subject matter of the investigations was thaw the sensitivity of the tested structures was affected by hydrogen, nitrogen dioxide and carbon dioxide. The experiments were performed at a temperature range from 30 °C to 150 °C in two carrier gases: nitrogen and synthetic air. The measurements were also aimed at characterization of the graphite oxide and graphene oxide. In our measurements we used (among others) techniques such as: Atomic Force Microscopy (AFM); Scanning Electron Microscopy (SEM); Raman Spectroscopy (RS); Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Microscopy (XPS). The data resulting from the characterizations of graphite oxide and graphene oxide have made it possible to interpret the obtained results from the point of view of physicochemical changes occurring in these structures.

Conducting proficiency tests with large numbers of participants are not a problem because the ISO standard 13528:2015 describes many indicators that allow for proper assessment. However, there are proficiency testing (PT) schemes that involve only few participants. In such situations, the same difficulties exist for the selection of proper indicators and the criteria for assessing the participants' achievements. The Institute for Chemical Processing of Coal in Zabrze, Poland organised a round of PT of the determination of gypsum parameters. The results from six participants from Polish research entities and independent laboratories and methodology for the organisation this PT are presented. The performance evaluation criteria were determined using participants results due to the inability to use the metrologically valid procedure. The performance of the participants was evaluated using z′ and zeta scores.

The growing demand for the reduction of anthropogenic CO₂ emissions has stimulated the development of CO₂ capture methods. One of the best capture methods comprises the calcium looping process, which incorporates calcium-based sorbents during the calcination and carbonation cycles. Czatkowice limestone may be considered to be a prospective chemical sorbent for the calcium looping process because of its formation characteristics. This paper addresses the thermogravimetric studies conducted under varying conditions of temperature and various concentrations of CO₂ during the carbonation cycles. Moreover, a kinetic analysis of the carbonation stage was performed for the calcined sample at varying temperatures. The kinetic parameters for calcination and diffusion were determined. In addition, there was an increase in the concentration of CO₂ with an increased carbonation conversion. The research results demonstrate that in further cycles of carbonation/calcination, the calcium sorbent reaches a higher rate of carbonation conversion with increased levels of CO₂.