Tom 120 (2023): Zeszyt 1 (January 2023)

This article presents the idea and mathematical model of a pumped storage power plant. PSPS Porąbka Żar was selected as the real object for modelling. Due to the specificity of the operation of an intervention-regulatory and scheduled nature related to the coverage of power demand in the power system, the possibility of different modes of operation was taken into account in the model. PorąbkaŻar power plant is a pearl of hydro-engineering on the global stage. It is the first underground and the second largest pumped storage power plant in Poland. It is located in Międzybrodzie Bialskie, in the Silesian province. The short distance between the upper reservoir of the power station, located on Mt. Żar, and the lower reservoir of the międzybrodzkie lake, the high average head of the power station of 432 m above sea level, create great opportunities for accessibility and interference in the operation of the power station. It is equipped with four reversible Francis turbine sets, which operate simultaneously with a total capacity of 500 MW in the generator mode and 542 MW in the pumping mode. Due to its high potential and short turn-on and turn-off times of the turbine sets, it plays an important role in the national power system. The mathematical model was made in Matlab -Simulink software. An important role in the control process of the facility is played by the forecast of both power demand and contingencies. The forecasting model is equipped with elements of artificial intelligence. In addition, the article shows the possibility of supplementing an operating power plant with hybrid elements. The analysis is supported by commentary and a number of charts.

The article presents simulation results of a developed model of PSP Solina. The model was designed and executed in the Matlab – Simulink interface. A modular approach was used to clearly distinguish characteristic elements of the model. Simulations of the model performance were carried out for a period of 365 days. The results were presented graphically. To simplify, the form of criteria defining on/off moments and defining the turbine/pump turbine operating mode was adopted. All constraints arising from the physical parameters and limitations of the cascade objects as well as those arising from the provisions of the current water management instructions for the Solina-Myczkowce cascade were taken into account. The model is a flexible proposal with which to develop and test decision-making mechanisms in the context of energy generation/consumption in operation. Due to the high potential and short on/off times of the turbine sets, the Solina EW plays an important role in the National Electricity System. An important role in the control process of the facility is played by the forecast of both power demand and contingencies. The analyses are supported by many charts and commentary.

The work presents the concept of a device for the measurement of the one-way speed of light. The minimum parameters of this device have also been determined based on the Special Theory of Ether without transverse contraction. The Special Theory of Ether is a relativistic theory of kinemat-ics with a universal frame of reference in which light propagates and is an alternative explanation for the null result of the Michelson-Morley experiment. An experiment based on the proposed device can be one of the ways to falsify the Special Theory of Relativity and Special Theory of Ether.

This paper presents selected mechanical and tribological properties of DLC coatings (diamond-like carbon coatings) and the results of an applied texture to improve these properties under specific circumstances. It presents the results of the selection of parameters for the laser-texturing process of DLC coatings using a picosecond laser with a wavelength of 343 nm.

Based on the commercial aluminium alloy powder blend (Alumix 431D) metal matrix composites reinforced with particles of SiC as well as TiC were produced by conventional powder metallurgy technology and the effect of the type and amounts of reinforced particles on the selected properties and microstructure of sintered composites were investigated. In particular, the densification behaviour, the wear resistance and the corrosion resistance in 3.5% NaCl solution were identified. It was stated that both the type and the weight fraction of carbide used as particulate reinforcement have a great impact on the properties of aluminium alloy matrix composites. It was shown that the introduction of titanium carbide has a more favourable effect on the properties of sintered Alumix 431D matrix composites in comparison to silicon carbide and the optimum content of TiC in composite is 4 wt. % due to the highest hardness, wear resistance (wear rate of 2.865·10⁻³ mm³/m) and simultaneously the best corrosion resistance (corrosion rate of 0.005 mm/year).

This study attempts to explain why the space in the centre of Katowice is formally called “The Market Square” even though the square itself no longer exists. Some archival documents and existing studies are analysed. The evolution of the market square in Katowice is presented against the background of historical and economic transformations, putting an emphasis on depicting valuable and interesting architecture that was irretrievably lost and replaced with entirely new urban fabric. Moreover, the article aims to show that the region of Upper Silesia does not only constitute industrial plants but also, created by the mixture of cultures and nationalities, other types of architecture, that was irretrievably lost. It was found out that the market is not actually the main square.

A method of creating a constitutive model of layered rocks based on an artificial neural network (ANN) is reported in this work. The ANN gives an implicit constitutive function ∑ⁿ⁺¹=F(∑ⁿ,ΔE ), relating the new state of homogenized stresses ∑ⁿ⁺¹ with the old state ∑ⁿ and with the increment of homogenized strains ΔE. The first step is to repeatedly run a strain- controlled homogenisation on an uni-dimensional finite element model of a periodic cell with elastic-plastic models (Drucker-Prager) of the components. Paths are created in (∑, E) space, from which, a set of patterns is formed to train the ANN. A description of how to prepare this data and a discussion on ANN training issues are presented. Finally, the procedure based on trained ANN is put into a finite-element code (ZSoil.PC) as a user-delivered constitutive function. The approach is verified by comparing the results of the developed model basing on ANN with a direct (single-scale) analysis, which showed acceptable accuracy.

The paper presents an analysis of the operational properties of paint coatings for use in military technology in the field of masking. The assessment of the properties was performed on the basis of measurements of the surface geometric structure and adhesion using the peel method. The measurements of specular gloss, colour in the range of 400-700 nm and reflectance in the range of 350-1200 nm were made in relation to the requirements of the Polish Defence Standard NO-80-A200. Coating systems are characterised by their low roughness and good adhesion. Due to their operational properties, the developed coating systems can be used on armaments and military equipment.