A mathematical model of the process of thermoelastic deformation and dissipative heating of elastomeric structural elements are assumed . The methods of prediction the longevity of structures based on the use of entropy fracture criteria are proposed. For solving of the link thermoelasticity problem of method of successive approximations is used.

The article presents the methodology for assessing the longevity of hard coal mines. Based on international experts’ assessments, important criteria for determining mine viability have been presented. The results refer to Polish coal mines in the area of the Upper Silesian Coal Basin, however, the methodology itself can be applied to other geological and mining conditions of mines elsewhere.

The results of structural analyses carried out using the MICMAC method for factors related to the mining geo-environment that may determine the longevity of individual hard coal mines are presented. The analyses were based on the results of expert surveys carried out using the Delphi method. The experts participating in the survey came from various countries and had extensive experience related to work or cooperation with hard coal mining. The criterion factors examined were assigned to two systems (groups) for which structural analysis was performed. The first group includes factors related to the level of exploitation hampering, while the second group includes factors related to hard coal quality and the availability of resources. As a result of the analyses the following were determined: the key factors which have the most significant influence on the system, result and goal factors, factors affecting the system and autonomous factors which have little effect on the system.

The obtained results allowed to determine which factors should be taken into account in the process of determining the longevity of a hard coal mine.

The investigation described herein discusses the morpho-anatomical characteristics of xylem parenchyma cells of European ash stems undergoing heartwood formation. The research material comprised of cross and radial sections of wood obtained from stems at breast height of 91-year-old ash trees, half of which had visible ash dieback symptoms. The radial section of the wood samples was stained with acetocarmine to detect nuclei and with I2KI solution to observe starch grains in parenchyma cells, both of radial and axial systems. Additionally, microscopic slides were stained with Alcianblue Safranin-O, and fluorescence microscopy was applied to detect lignified cell walls. The color of sapwood and heartwood distinctly differed – heartwood extracts were detected in approx. 47 rings. Most of the parenchyma cells had nuclei present in both wood zones. Also starch grains were detected in the majority of the tree rings of the researched samples. All of the xylem parenchyma cell walls of axial and radial systems were lignified. The research revealed that lignification, parenchyma cells death and the release of heartwood extracts are processes remote in time and space. Furthermore, parenchyma cell walls lignification did not figure as a sign of the upcoming parenchyma cells death. Based on the current research, ash dieback disease might slightly impact the development paths of parenchyma cells. Compared with scores reported for other trees, European ash parenchyma cells longevity is indeed remarkable.