The paper deals with the application of the extended Kalman filters in the control structure of a two-mass drive system. In the first step only linear extended Kalman filter was used for the estimation of mechanical state variables of the drive including load torque value. The estimation algorithm showed good robustness to mechanical parameters variations. For the system with some parameters changing in the wide range, simultaneous estimation of the state variables and chosen system parameters is required. For this reason the non-linear extended Kalman filter, which estimates simultaneously state variables and mechanical parameters of the two-mass drive system, was developed. Parameters of covariance matrices of used Kalman filters were set using the genetic algorithm. Both proposed estimators were investigated in simulation and experimental tests, in the open-loop operation and in the state-feedback control system of the two-mass system.

The paper deals with the application of the feed-forward and cascade-forward neural networks to mechanical state variable estimation of the drive system with elastic coupling. The learning procedure of neural estimators is described and the influence of the input vector size and neural network structure to the accuracy of state variable estimation is investigated. The quality of state estimation by neural estimators of different types is tested and compared. The simple optimisation procedure is proposed. Optimised neural estimators of the torsional torque and the load machine speed are tested in the open-loop and closed-loop control structure of the drive system with elastic joint, with additional feedbacks from the shaft torque and the difference between the motor and the load speeds. It is shown that torsional vibrations of the two-mass system are damped effectively using the closed-loop control structure with additional feedbacks obtained from the developed neural estimators. The simulation results are confirmed by laboratory experiments.

The article analyses the results of mass survey conducted in the framework of the project of the Volkswagen Foundation “Bi- and multilingualism between intensification of conflict and conflict resolution. Ethno-linguistic conflicts, language politics and contact situations in post-Soviet Ukraine and Russia”. Research’s aim was to understand to what extent the state language policy in the area of mass media and cultural sphere meet the expectations of the citizens of Ukraine. It underlines regionally marked attitude towards the strategy of language policy: the Western part of the country prefers Ukrainian language, South – Russian, and Center and North take intermediate positions.

Methods and results of mass movement measurements on mountain slopes in northwestern Wedel Jarlsberg Land are presented in connection with morphoclimatic zones. Debris movement was investigated using fishing nets while movement of solifluction tonques was studied with series of nails. Marks and lines crosswise the investigated forms were also painted. Creeping of stone belts was measured with a use of tree-nails. Observations of these measuring points after twelve months show usability of employed methods for a record of mass movements.

The research paper presents the results of testing the strength and technological properties of molding sand with gypsum binder, the bonding process proceeded: naturally or conventionally. The tests included mass containing (parts by weight): 78 pbw. Grudzeń-Las quartz sand, 22 pbw. plaster gypsum "Dolina Nidy” and 9 pbw. water. Measurements of compressive strength, shear, tensile and bending as well as permeability and looseness were carried out on standard cylindrical samples kept in the air for 1 - 96 hours or dried at 110 oC for 1 - 8 hours. The results of the analysis were analyzed in connection with the mass structure and construction binding bridges warp grains observed with a scanning microscope (SEM). The influence of drying intensity on the bonding process and related mass properties has been demonstrated, especially from the point of view of the possibility of selection and / or intensification of a specific curing method for use in the production of gypsum binger molds and cores.

Traditional mass balance measurements by stake readings and snow surveying have been conducted annually since 1996 on the Waldemar Glacier (= Waldemarbreen) in northwest Spitsbergen, Svalbard. Several indirect methods were also used for estimating its mass balance. These methods were divided into two major groups: climatological and geodetic. A comparison of the latest map (2000) with that of 1978 and climatological records enable us to calculate the change in the mass balance of Waldemarbreen over 34 years. These methods include air temperature and degree-day (PDD) models. The average mass balance of Waldemarbreen, computed by climatological methods, was -0.42 m a-1 of water equivalent (w.e.) for the period 1970-2004, and -0.51 m w.e. for 1996-2004. These balances were compared with the glaciological balance for the period 1996-2004, -0.53 m w.e.. The mass balance was also computed using geodetic method, giving -0.52 m of w.e. from 1978 to 2000. It is suggested that, from these results, the approach used for Waldemarbreen might be also useful for estimation the mass balances of other small Svalbard glaciers which terminate on land.

Classification of water masses in the area investigated during the 1981 FIBEX Expedition and two winter expeditions at the "H. Arctowski" Station using the method of Empirical Orthogonal Functions (EOF) is presented. Four basic water masses (warm and cold Bellinghausen Sea surface waters, surface Weddell Sea waters, Circumpolar Warm Deep Water (CWDW) and the transitional zone) were observed in the area and a significant dependence of water masses distribution ón depth was found. A strong winter increase in the Weddell Sea waters influence was recorded.

A “rock bridge”, defined as the closest distance between two joints in a rock mass, is an important feature affecting the jointed rock mass strength. Artificial jointed rock specimens with two parallel joint fractures were tested under uniaxial compression and numerical simulations were carried out to study the effects of the inclination of the rock bridge, the dip angle of the joint, rock bridge length, and the length of joints on the strength of the jointed rock mass. Research results show: (1) When the length of the joint fracture, the length of the rock bridge, and the inclination of the rock bridge stay unchanged, the uniaxial compressive strength of the specimen gradually increases as the inclination of the joint fracture increases from 0° to 90°. (2) When the length of the joint fracture, the length of the rock bridge, and the inclination of the joint fracture stay unchanged, the uniaxial compressive strength of the specimen shows variations in trends with the inclination of the rock bridge increasing from 30° to 150° (3). In the case when the joint is angled from the vertical loading direction, when the dip angle of the joint fracture, the inclination of the rock bridge, and the length of the rock bridge stay unchanged, the uniaxial compressive strength of the specimen gradually decreases with an increasing length of joint fracture. When the dip angle of the joint fracture, the inclination of the rock bridge, and the length of the joint fracture stay unchanged, the uniaxial compressive strength of the specimen does not show a clear trend with an increase of the length of the rock bridge.

This paper contains the result of the comparison of photogrammetric records of the state of the front zone of the Werenskiold Glacier over the period 1957-1978. Two 1:5000 maps were compared. The ice volume loss at 20 m altitude intervals (only as far up as 200 m over the sea level) and changes in the ice thickness were analysed with a network of basic squares with a 50 m side in the field, using an Odra 1305 computer. This permitted a map of the altitude changes in the glacier front to be plotted with isolines every 2.5 m. The results of the photogrammetric investigations were compared with ablation observations using ablations stakes. Taking account of the motion of the lobe the total and the mean annual ice volume loss in the front zone of the Werenskiold Glacier was evaluated for the period in question.

In the examined area three types of waters have been recorded: Surface Waters of winter modification, Warm Deep Waters and East Bransfield Strait Waters. Geographical location of Scotia Front is similar to that observed in previous years. The dynamics of waters within the examined area is high. It is reflected not only in physical and chemical parameters but also in the distribution of chlorophyll α. In the Front its total amount in a water column is greater than outside.

A simple empirical study on the orientation, diameter, and extent of radial fractures (long and short) at the vicinity of the face-perpendicular preconditioned boreholes is described. Homogenous and heterogeneous mining faces were considered when studying the orientation of radial fractures, four and five face-perpendicular preconditioning practices were used to investigate the outspread and diameter of radial fractures from one blasted drill hole to another. Long radial fractures were observed to be developed along the direction of the maximum principal stress and short radial fractures were observed to be developed along the direction of the intermediate principal stress in a homogenous mining face. On the other hand, long radial fractures were observed to be developed along the direction of the intermediate principal stress, while short radial fractures were observed to be developed along the direction of the maximum principal stress when the mining faces subjected to heterogeneous rock mass. The diameters of the radial fractures observed were inconsistent and were not nine times the diameter of the original borehole. Furthermore, the extent of radial fractures from one borehole to another was noted to be gradually improved when the additional of preconditioned borehole was in place. This study maintained that the orientation of radial fractures is mostly controlled by the rock properties, however, extend and the diameters of the radial fractures are controlled by rock properties, the effectiveness of the stress wave and gas pressure and brittleness of the rock mass.

Underground mining extraction causes the displacement and changes of stress fields in the surrounding rock mass. The determination of the changes is extremely important when the mining activity takes place in the proximity of post-flotation tailing ponds, which may affect the stability of the tailing dams. The deterministic modeling based on principles of continuum mechanics with the use of numerical methods, e.g. finite element method (FEM) should be used in all problems of predicting rock mass displacements and changes of stress field, particularly in cases of complex geology and complex mining methods. The accuracy of FEM solutions depends mainly on the quality of geomechanical parameters of the geological strata. The parameters, e.g. young modulus of elasticity, may require verification through a comparison with measured surface deformations using geodetic methods. This paper presents application of FEM in predicting effects of underground mining on the surface displacements in the area of the KGHM safety pillar of the tailing pond of the OUOW Żelazny Most. The area has been affected by room and pillar mining with roof bending in the years 2008-2016 and will be further exposed to room-and-pillar extraction with hydraulic filling in the years 2017–2019.

The main energy source in Poland is still hard coal and lignite. The coal combustion process produces large quantities of by-products, e.g. fly ashes, slag furnace and harmful chemical gases (CO2, NOx, sulfur compounds) which enter the atmosphere. Fly ashes, due to their being fine grained (cement-like), chemical and phase compound and reactivity, have also been widely used in various technological solutions e.g. in the production of ordinary cement, hydro-technical cement and the new generation of cements. The adequate amount of fly ashes additive has a positive effect on fresh and hardened cement slurry properties. What is more, it allows for the pro-ecological and economic production of cement mix The exploitation of natural resources is connected with performance mining excavations at different depths. After a certain period of time, those voids break down which, in turn, leads to the slip of upper layers and the so-called landslides forming on the surface. This situation imposes the necessity of basis and sealing rock mass reinforcement. To minimize the risk connected to geotechnical problems on the mining areas, there is a need to use engineering solutions which could improve soil bearing in a universal, economical and efficient way. This leads to the development of new cement slurry recipes used during geoengineering works, especially in the mining areas. Moreover, economic requirements are forcing engineers to use less expensive technical and technological solutions simultaneously maintaining strength properties. An example of such a solution is to use suitable additives to cement slurry which could reduce the total unit cost of the treatment.

Rock excavation is a basic technological operation during tunnelling and drilling roadways in underground mines. Tunnels and roadways in underground mines are driven into a rock mass, which in the particular case of sedimentary rocks, often have a layered structure and complicated tectonics. For this reason, rock strata often have highly differentiated mechanical properties, diverse deposition patterns and varied thicknesses in the cross sections of such headings. In the field of roadheader technology applied to drilling headings, the structure of a rock mass is highly relevant when selecting the appropriate cutting method for the heading face. Decidedly differentiated values of the parameters which describe the mechanical properties of a particular rock layer deposited in the cross section of the drilled tunnel heading will influence the value and character of the load on the cutting system, generated by the cutting process, power demand, efficiency and energy consumption of the cutting process. The article presents a mathematical modelling process for cutting a layered structure rock mass with the transverse head of a boom-type roadheader. The assumption was made that the rock mass being cut consists of a certain number of rock layers with predefined mechanical properties, a specific thickness and deposition pattern. The mathematical model created was executed through a computer programme. It was used for analysing the impact deposition patterns of rock layers with varied mechanical properties, have on the amount of cutting power consumed and load placed on a roadheader cutting system. The article presents an example of the results attained from computer simulations. They indicate that variations in the properties of the rock cut – as cutting heads are moving along the surface of the heading face – may have, apart from multiple other factors, a significant impact on the value of the power consumed by the cutting process.