Geology, Geophysics & Environment

Seismic and rockburst hazards represent significant challenges during the longwall mining of coal seams. One analytical approach to assess the potential for rockburst hazards involves reconstructing the stress conditions within the rock mass. This article reports on the findings from three-dimensional (3D) numerical modeling aimed at examining the distribution of maximum shear stress within the rock mass amid the longwall mining operations of the 703/1 coal seam in a mine situated in the Upper Silesian Coal Basin, Poland which was disrupted by a rockburst incident. On the day of the rockburst, substantial concentrations of maximum shear stress were identified in a thick sandstone layer proximate to the boundary of the overlying 624 coal seam located significantly above the 703/1 coal seam. The calculated maximum shear stress demonstrated an increase of approximately 80% over the values observed in the absence of edge effects. Furthermore, also higher concentration of maximum shear stress was identified within the geologically weaker strata adjacent to the 703/1 coal seam. These observations facilitated the classification of the examined rockburst as a stress-stroke phenomenon. Additionally, the study determined the spectral parameters of the tremor, which possessed an energy of 9.8 × 10$^{7}$ J and triggered the analyzed rockburst. The ratio of the seismic energy of S and P-waves confirmed a shear mechanism in the focus. The scope of inelastic deformation within the focal zone was also quantified. Following the event, the rock mass that had been destressed due to the significant tremor and subsequent rockburst exhibited reduced seismic activity upon the resumption of longwall mining of the 703/1 coal seam.Krakówwersja wydawnicz

Energetyka Rozproszona

Krakówwersja wydawnicz

Biomass & Bioenergy

The management of energy contained in waste is an important research topic. Among many high-energy wastes, pellets are produced from refuse-derived fuels (RDF) and lignocellulosic biomass. This study investigated hightemperature pyrolysis (800 °C) of biomass and RDF pellets. Experiments were conducted in two reactors: i) on a microscale (thermogravimetric analysis) and ii) on a laboratory scale (fixed-bed reactor) to investigate the yields of the products (char, liquid fraction, and gas) and to characterise products toward their further application. The RDF char contained less carbon than the material before pyrolysis. The carbon content of the biomass char was 90%, almost twice that of the raw material. The biomass and RDF chars were chemically and physically activated to increase their specific surface areas. The chemically activated biomass char had a sorption capacity of 156.2 mg/CO2 at 25 °C and 0.1 MPa. The kinetics of CO2 sorption were also examined, and the maximum uptake was observed after 2–3 min. The higher heating value of the liquid phase, including the organic condensed phase, was 28.6 and 25.8 MJ/kg for pyrolysis of biomass and RDF pellets, respectively. The pyrolysis gas composition was analysed separately for the heating and isothermal processes. Due to the high CO, CH4, and H2 contents, the gas from the heating stage was characterised by a much higher heating value.innypostprin

Studia Humanistyczne AGH

The aim of this article is to show that referring to the concept of well-being in a broad sense (not only in terms of physical health, but also in an emotional or social sense) is used in food advertising to encourage consumers to purchase food products. However, referring to the idea of wellbeing in food advertising does not necessarily imply building a ‘positive food culture’, that is, one that supports healthy eating habits (Mingay et al., 2021), as it can also be found in advertisements for sweets or fast food. One of the theoretical references used in the article is the concept of food for wellbeing (Block et al., 2011), which complements the hitherto popular food for health concept.Celem artykułu jest pokazanie, że nawiązanie do pojęcia dobrostanu w szerokim rozumieniu (nie tylko w aspekcie zdrowia fizycznego, ale również w sensie emocjonalnym czy społecznym) wykorzystuje się w reklamach żywności, aby zachęcić konsumentów do nabywania produktów spożywczych. Samo odwoływanie się do idei dobrostanu w reklamie żywności nie oznacza jednak budowania „pozytywnej kultury żywieniowej”, to znaczy takiej, która wspiera zdrowe nawyki żywieniowe (Mingay et al., 2021), ponieważ takie nawiązania można znaleźć również w reklamach słodyczy czy jedzenia typu fast food. Jednym z zastosowanych w artykule odniesień teoretycznych jest koncepcja food for wellbeing (Block et al., 2011), która stanowi uzupełnienie popularnej dotychczas koncepcji food for health.Krakówwersja wydawnicz

Mining - Informatics, Automation and Electrical Engineering

Z uwagi na zmiany klimatyczne coraz częściej poruszane są zagadnienia dotyczące gazów cieplarnianych i ich emisji. Metan, obok dwutlenku węgla, uznawany jest za jeden z najistotniejszych gazów cieplarnianych, którego ograniczenie emisji może przynieść w krótkim czasie zauważalne korzyści dla środowiska. Emisje antropogeniczne stanowią około 60 całkowitej emisji metanu, stąd też to właśnie w tym obszarze najczęściej poszukiwane są rozwiązania ograniczające emisje tego gazu. Przedmiotem opracowania jest system ujęcia metanu w kopalni „Pniówek” należącej do Górnośląskiego Zagłębia Węglowego (południowa Polska) oraz możliwości zagospodarowania tego gazu za pomocą silników trójgeneracyjnych. W artykule omówiono możliwość wykorzystania metanu z kopalń węgla kamiennego w celu ograniczenia jego emisji do atmosfery oraz z uwagi na możliwość jego opłacalnego wykorzystania. Autorzy przedstawiają zastosowanie układu trójgeneracyjnego, w którym metan z kopalni jest spalany w silnikach gazowych i wykorzystywany do produkcji energii elektrycznej, cieplnej i chłodniczej. Pozwala to na zmniejszenie emisji metanu do atmosfery przy jednoczesnym zwiększeniu efektywności wykorzystania węgla. W artykule przedstawiono wyniki badań przeprowadzonych w kopalni węgla kamiennego w Polsce i na tym przykładzie wskazano na ekologiczne i ekonomiczne korzyści wynikające z zastosowania układu trójgeneracyjnego.Krakówwersja wydawnicz

Computer Science

Evolutionary algorithms mimic some elements of the theory of evolution. The survival of individuals and the ability to produce offspring play significant roles in the process of natural evolution. This process is called natural selection. This mechanism is responsible for eliminating weaker members of the population and provides the opportunity for the development of stronger individuals. The evolutionary algorithm, an instance of evolution in the computer environment, also requires a selection method – a computerized version of natural selection. Widely used standard selection methods applied in evolutionary algorithms are usually derived from nature and prefer competition, randomness, and some kind of “fight” among individuals. But the computer environment is quite different from nature. Computer populations of individuals are typically small, making them susceptible to premature convergence towards local extremes. To mitigate this drawback, computer selection methods must incorporate features distinct from those of natural selection. In the computer selection methods randomness, fight, and competition should be controlled or influenced to operate to the desired extent. This work proposes several new methods of individual selection, including various forms of mixed selection, interval selection, and taboo selection. The advantages of incorporating them into the evolutionary algorithm are also demonstrated, using examples based on searching for the maximum ?-clique problem and traditional Traveling Salesman Problem (TSP) in comparison with traditionally considered highly efficient tournament selection, deemed ineffective proportional (roulette) selection, and other classical methods.Krakówwersja wydawnicz

Doskonalenie procesów i produktów w wybranych gałęziach gospodarki

124 str.Krakówmonografi

Geology, Geophysics & Environment

The study analyzes changes in the physico-chemical parameters in a 400 cm2 artificial water reservoir with distilled water, exposed to a 2-week (±2 days) period of atmospheric conditions in Krakow. After nearly 500 days, dry and wet deposition caused a shift from neutral to acidic pH levels (7.30–5.12, averaging 6.22 pH) and an average electric conductivity of 19.5 µS/cm (1.6–143.0 µS/cm). The study investigated chemical and biological pollutants, including pollen and fungal spores. Three distinct air quality periods were identified: (1) characterized by vehicle and combustion-related pollutants (Oct-Jan), (2) a transitional phase with increased biological particles (Feb-May), and (3) dominated by pollen and fungal spores (Jun-Sep). Despite peak air pollution in the warmest months, air temperature showed an inverse relationship with pollutant concentration, possibly due to decreased air humidity. Precipitation positively impacted air quality. The artificial reservoir received a total of 0.7 kg of air pollutants ($723.6 mg/m^{2}$ of surface water table). This corresponds to an annual load of 0.5 kg (551.4 mg) and a daily load of 1.51 mg. The reservoir’s pollutant capture capacity was estimated at 28% ±21% (mean±SD), with a critical value of 12%. The study evaluated Krakow’s surface water reservoirs’ capacity to mitigate air pollution, indicating potential benefits for urban air quality.Krakówwersja wydawnicz

Geology, Geophysics & Environment

Among the many factors determining the quality of river waters, the influence of the hyporheic zone (HZ) is gaining in importance. Watercourses that exist in the higher parts of catchments are relatively steep and shallow, and the topography of their valleys activate hyporheic flow. The main goal of this work is to assess the impact of the HZ on the hydrochemical state of the head watercourse of the Malina in the suburbs of the city of Zgierz with the focus on biogenic compounds. The riverbed of this stream was researched across two distinct stretches: erosive and accumulative, which differ in the conditions for the hyporheic zone’s interaction with the riverbed. The nutrients are delivered to the stream mainly in the erosive stretch and are related to the inflow of nutrient-rich groundwater from the urbanised catchment. The pollutants transported down by the stream are then delivered to the HZ in the accumulative stretch, where nitrates are denitrified and phosphates are deposited with the suspension. Ammonium nitrogen, in turn, is introduced into the stream from the HZ as a result of either the process of ammonification of organic matter deposited in sediments or inflow with polluted groundwater. The results indicate that the winter season is the most important period in shaping the interaction of river waters with the underlying hyporheic zone, in which the causal side of the relationship should be associated with the subchannel environment, and the effects are recorded in the river waters.Krakówwersja wydawnicz

Computer Methods in Materials Science

In weld-based manufacturing processes such as welding and metal deposition additive manufacturing (AM), the weld bead is a direct indicator of manufacturing quality. For example, the geometry of the weld bead was optimized to a net shape which outperformed conventional geometries. Automatic monitoring of weld bead is thus of prime importance for welding process control and quality assurance. This paper develops a general-purpose convolutional neural network (CNN) for pixel-level detection and monitoring of beads, regardless of welding materials, machine, manufacturing conditions, etc. To achieve the generality, we collected a great variety of welding images containing 2677 single-line beads from 231 research articles, followed by pixel-wise hand-annotation. Consequently, the trained CNN can recognize different beads from various backgrounds at a pixel level. Case studies show that compared to the image-level classification in prior research, its pixel-level labeling permits real-time, complete characterization of weld beads (e.g., detailed morphology, discontinuity, spatter, and uniformity) for more informed process control. This research represents a significant step towards developing a truly human-like monitoring system with low-level scene understanding ability and general applicability.Krakówwersja wydawnicz