Practical Use of Measuring the Deflection of Roof Layers in the Assessment of the Stability of Mining Excavations in the Polish Copper Ore Mine “Polkowice-Sieroszowice”

The paper presents the results of long-term continuous measurements of the deflection of the roof layers in the underground copper mine Polkowice-Sieroszowice, Poland belonging to KGHM Polska Miedź S.A. The measurements were performed with the use of the inclinometric method consisting of continuous registration of changes in the angle of inclination of the roof strata. The measurements were carried out using an inclinometer sensor fixed to the end of a rockbolt in the roof. Measurements presented in the article were made in various regions of the underground mine. The monitoring covered: The exploitation front, machinery chamber and the region of the experimental longwall mining of copper ore. The obtained results proved the usefulness of the developed method in the process of the evaluation of the stability of mining excavations. The sensors were highly sensitive and performed the measurements in a simple way; highly accurate and reliable results were obtained.

Formation and development of the Ukrainian network of meteor radio observations

During the decade of research, the Research Institute “Mykolaiv Astronomical Observatory” (RI “MAO”) developed hardware and software for monitoring, extracting, and calculating the parameters of meteor phenomena using the forward scattering by meteor ionized trail of the signals of over-the-horizon FM-stations broadcasted in the frequency range of 88—108 MHz. This allowed creating a network of observations of meteor phenomena in the radio range, which consists of six stations located in Mykolaiv (three stations), Rivne, Lviv, and Hlukhiv. The stations have identical hardware and software. Yagi-Uda antennas with six or eight horizontal vibrators and SDR receivers based at RTR2832U microchip are used to receive radio signals. The station software performs continuous registration and analysis of received radio signals at the output of quadrature detectors of the receivers, automatic detection of moments of appearances of meteor reflections, formation, and sending by e-mail daily reports on detected meteor phenomena. Equipment setup and current monitoring of stations operations are carried out by the RI «MAO» using remote access to station computers via the Internet. Monthly reports on the number of meteor events recorded by each station are posted on the site of Radio Meteor Observation Bulletin (RMOB). The article presents the results, obtained by the network in 2017—2019, confirming a correspondence of daily variations in the number of meteors registered by network stations, to the known dependence (observation of meteors in the apex and antapex), as well as a correspondence between the expected characteristics (in time and intensity) of three meteor showers (Perseids, Geminids and Quadrantids) and that had been obtained by the network. Recommendations are also given in the article for additional research aimed at achieving the main goal, namely, expanding information about meteor phenomena, including the estimating of kinematic parameters (velocities, radiants) of meteoroids and their relationship with potentially hazardous asteroids.

DEVELOPMENT OF AN APPROACH FOR ASSESSING THE HARDNESS OF COATINGS WITH DYNAMIC INDENTATION

The article discusses the features of the method for assessing the hardness of coating materials based on the dynamic indentation approach, the essence of which is the continuous registration of the process of contact interaction of the indenter with the material under study. According to the research results, a regression dependence was obtained in the form of a polynomial of the second degree, which makes it possible to assess the hardness of a galvanic nickel coating.

Curve registration

This article deals with curve registration, which refers to methods for aligning prominent features in a set of curves by transforming their abscissa variables. It first illustrates the concepts of amplitude and phase variation schematically and with real data before defining the time-warping functions and their functional inverse. It then describes the decomposition of total mean squared variation into separate amplitude and phase components, along with an R2 measure of the proportion of functional variation due to phase in a sample of curves. It also considers landmark registration, novel ways of defining curve features, continuous registration, and methods based on structured models for amplitude and phase variation combined with more statistically oriented fitting methods such as maximum likelihood or Bayesian estimation. The article concludes with a brief survey of software resources for registration.

The Effect of a Hydrocarbon Fragment in a Molecule on Depressant Activity of Resins

The effect of resins on solidification of paraffin solutions has been studied by vibration viscosimetry. This technique was used for studies of coagulating liquids, since the sample structure is less affected by mechanical oscillations compared to traditional rotary and linear shears. The installation developed for studies of thermo-induced phase transitions and the measurement procedure are described. The viscosimetric technique allows continuous registration of rheological properties with changing temperature, and has proved to be quite sensitive to small amounts of resins in model paraffin solutions. Measurements have been performed for resins extracted from methane-naphtene crudes of various West Siberia oil deposits. Dependencies of viscosity on temperature have been measured and are presented below for various concentrations of resins (up to 3 %) in paraffin solutions. It is demonstrated that increase of resin concentration results in a shift of the inflexion point on the viscosity-temperature curve to lower temperatures. A positive correlation has been found between depressant activity and average dimensions of aliphatic fragments of the resin molecu.