AGH (Akademia Górniczo-Hutnicza) University of Science and Technology: Journals
Not a member yet
2379 research outputs found
Sort by
Współczesne zagadnienia rozwoju elektroenergetyki
Full text linkW artykule przedstawiono wybrane obszary działalności naukowej zespołu badawczego Elektroenergetyka funkcjonującego na Wydziale Elektrotechniki, Automatyki, Informatyki i Inżynierii Biomedycznej AGH, które dotyczą rozwoju elektroenergetyki w kontekście zachodzących procesów transformacji energetycznej i wynikającego z nich rozwoju energetyki rozproszonej. Opisano zagadnienia analizy i modelowania systemów elektroenergetycznych, integracji rozproszonych źródeł wytwórczych z systemem elektroenergetycznym,wspomagania projektowania układów izolacyjnych urządzeń elektroenergetycznych oraz metod diagnostyki układów izolacyjnych w elektroenergetyce. Przedstawiono również model zarządzania dystrybucją energii w sieciach SMART łączący prognozowanie zapotrzebowania, dynamiczne ceny rynkowe oraz warunki pogodowe z optymalizacją pracy magazynu energii i inwertera sieciowego
Optimized lossless audio compression using DCT energy thresholding and machine learning technique
Full text linkIn this paper, a novel lossless audio compression technique has been proposed, utilizing the Discrete Cosine Transform (DCT) coefficient-controlled technique based on energy thresholding, an XOR-based neural network compression model, and a CNN model. Initially, the DCT is applied to the input audio signal to achieve better energy compaction, followed by transforming selected DCT coefficients into a compressed binary stream. Subsequently, this binary stream is passed to two prediction-based optimized models: an XOR model and a CNN model for further compression. The binary stream is first processed by the neural network model for XOR operation, and the resulting output is then fed into a CNN model to reduce data dimensionality and generate compressed audio data. The simulation findings are analyzed using various statistical and robustness measures and compared with existing approaches
Trace elements and rare earth elements in post-mining pit lakes of the Muskau Arch (Poland): AMD-related enrichment and toxicity assessment
Full text linkThis study presents results for trace elements (TEs) and rare earth elements (REEs) in five pit lakes located within the Muskau Arch, one of the largest regions in Central and Eastern Europe affected by acid mine drainage (AMD). Concentrations of TEs (Ag, Al, As, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, Sb, Sc, Se, Th, Tl, U, V, Zn) and REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) were determined using inductively coupled plasma triple quadrupole mass spectrometry (ICP-QQQ-MS). The highest concentrations were recorded for Fe (0.14–156.9 mg/L), which was the dominant TE in all pit lakes except MA1, where Al was dominant. PCA indicated that TEs such as Al, Be, Co, Fe, Li, Mn, Ni, Rb, Sc, Th, and Zn were strongly associated with pit lakes affected by AMD. Two subgroups were identified: (1) Be, Co, Ni, and Zn, which correlated with Al and low pH, and (2) Fe, Mn, Li, Rb, and Th, which correlated with slightly higher pH and anoxic and more reducing conditions. The toxicity analysis of TEs revealed substantial variation among the pit lakes (from extreme to low toxicity) and indicated that the most important TEs contributing to water toxicity were Al, Mn, Zn, and Ba. Total REE concentrations ranged from 0.15 μg/L to 149.3 μg/L, with by far the highest values recorded in MA2, and their concentrations were strongly influenced by pH. The pit lakes generally exhibited LREE (including La to Eu) enrichment, as well as a weaker MREE (including Sm to Dy) enrichment. Positive Gd anomalies were identified at all sampling points. Additionally, positive Eu anomalies were observed in all pit lakes except MA2, which was the most strongly affected by AMD, and positive Tb anomalies were recorded primarily in samples influenced by AMD
Variability factors of 40K radionuclide origin in meteorites
Full text linkThis study confirms the theory of the variability of the origin of radioactive potassium in various meteorite classes, generated from the dynamic nucleosynthesis (primordial) process, and other processes induced by the solar/cosmic-radiation activation or fractionation caused by the impact vaporization mechanism. High-precision radioactive 40K analysis confirms the differences between various types of meteorites. The concentrations of potassium change from 0.50 ±0.02 Bq/kg (NWA 15015, mesosiderite) to 26.2 ±1.2 Bq/kg (Chelyabinsk, LL chondrite) i.e. three orders of magnitude. All radiometric measurements have been made using a low-background gamma spectrometry system. Additionally, a set of common minerals – Fa (fayalite in olivine), Fs (ferrosilite), and Wo (wollastonite in pyroxenes) – was applied (MetBase n.d.). For the radionuclides factor variability, the principal component analysis (PCA) for the chemometric analysis has been applied. Two factors of the 40K variability have been identified, described, and explained. In this study, PCA was applied for the interpretation of the 40K potassium origin sources in 32 meteorite specimens, represent various groups and classes of meteorites.Two significant PCA factors of variability have been identified, PC1 (51.04%) and PC2 (30.68%), assigned as an activation process by cosmic radiation exposure and a nucleosynthesis mechanism (primordial), respectively.Niniejsze badania potwierdzają teorię zmienności pochodzenia radioaktywnego potasu K-40 w różnych klasach meteorytów, generowanego z dynamicznego procesu nukleosyntezy (pierwotnego procesu) i innych procesów indukowanych przez aktywację lub frakcjonowanie. Precyzyjna analiza aktywności izotopu K-40 potwierdza różnice między różnymi typami meteorytów. Stężenia potasu zmieniają się od 0,50±0,02 [Bq/kg] (NWA 15015, mezosyderyt) do 26,2±1,2 [Bq/kg] (Czejabińsk, chondryt LL), tj. o trzy rzędy wielkości. Wszystkie pomiary radiometryczne zostały wykonane przy użyciu systemu niskotłowej spektrometrii promieniowania gamma. Dodatkowo zastosowano zestaw powszechnych minerałów, Fa – fajalit w oliwinie i Fs – ferrosilit, Wo – wollastonit w piroksenach (źródło metbase.org). W tym badaniu zastosowano analizę PCA do interpretacji źródeł pochodzenia potasu 40K w 32 okazach meteorytów, reprezentujących różne grupy i klasy meteorytów. Zidentyfikowano dwa istotne czynniki zmienności PCA, PC1 (51,04%) i PC2 (30,68%), przypisane odpowiednio procesowi aktywacji przez ekspozycję na promieniowanie kosmiczne i mechanizmowi nukleosyntezy
Geothermal water and energy management in Poland - the direction for effective use in the Polish Lowlands
No full textThe article presents the possibility of utilising the available potential of the main geothermal reservoirs in Poland, i.e. the Lower Jurassic and Lower Cretaceous, by using the existing infrastructure in the form of still-operating district heating networks. The suggested solution, therefore integrates the resource side with the infrastructure side. This approach should significantly accelerate the implementation of the proposed solutions, supporting the achievement of the ambitious objectives of Poland’s Energy Policy 2040. Geothermal resources in Poland are characterised by low enthalpy and low temperature. Their temperature is often too low for direct utilisation in systems relying solely on geothermal energy. Existing district heating networks require significantly higher heating medium temperatures during specific periods (when low ambient air temperature is observed). Using existing boilers as peak energy sources while employing geothermal energy as the base load for meeting annual heating demands appears to be an attractive and feasible technical option. Poland, alongside Denmark, Latvia, Finland, Estonia, and Lithuania, is among the countries with the highest density of district heating networks. These networks serve as invaluable infrastructure, reducing the costs associated with geothermal energy extraction. However, this infrastructure is under real threat from the trend towards decentralised energy systems. The liquidation of district heating networks would be irreversible, further exacerbated by the lack of access to clean and alternative energy carriers to replace fossil fuels. It has been demonstrated that, in most analysed cases, the combination of available geothermal resources and district heating infrastructure can successfully contribute to achieving the assumed goals of Poland’s Energy Policy. In the best locations, the share of renewable energy exceeded 80%, with an average of around 50%. The total reduction of CO2 emissions is estimated as 1.16 million tonnes yearly. The article draws attention to the slow but positive change in the electricity mix, in which the share of RES is growing. This trend is extremely beneficial for popularising heat pumps powered by electricity using geothermal resources as a low-temperature energy carrier
“Yizkor”: A Case of Holocaust Memory Activism In a Czech Village
Full text linkThe article explores the construction and preservation of Holocaust memory in the small Czech village of Kosova Hora. The study, based on focus group interviews, reveals how local Holocaust memory is shaped by a unique combination of activism, local history, and communal practices. The article highlights the role of a Jewish couple who, by rescuing and restoring the village synagogue during the Communist era, created a central site for Holocaust remembrance. This act of preservation catalyzed broader local engagement, resulting in a collective effort to remember the Jewish community that once thrived there. The synagogue now serves not only as a cultural and educational center but also as a place for religious commemoration, despite the absence of a local Jewish population. The research concludes that such localized efforts are crucial for sustaining Holocaust memory, showing how minority activism can embed itself within majority memory, even in small and seemingly ordinary communities.The article explores the construction and preservation of Holocaust memory in the small Czech village of Kosova Hora. The study, based on focus group interviews, reveals how local Holocaust memory is shaped by a unique combination of activism, local history, and communal practices. The article highlights the role of a Jewish couple who, by rescuing and restoring the village synagogue during the Communist era, created a central site for Holocaust remembrance. This act of preservation catalyzed broader local engagement, resulting in a collective effort to remember the Jewish community that once thrived there. The synagogue now serves not only as a cultural and educational center but also as a place for religious commemoration, despite the absence of a local Jewish population. The research concludes that such localized efforts are crucial for sustaining Holocaust memory, showing how minority activism can embed itself within majority memory, even in small and seemingly ordinary communities
3-D Microstructure Reconstruction of Tetragonal Zirconia Polycrystalline
Full text linkThe microstructure of a material is fundamental to its properties and behavior under mechanical and thermal loads. Understanding the internal structure of a material and controlling the microstructure at the stage of ceramic materials synthesis are essential for designing materials with desired properties. This study focuses on the three-dimensional reconstruction of the microstructure of yttria-stabilized tetragonal zirconia polycrystalline (TZP). The goal was to create accurate digital models of the microstructure, which could be used for further material analysis.
The study utilized images obtained through scanning electron microscopy (SEM), based on which the basic stereological parameters were determined. The microstructure reconstruction was performed using the Laguerre tessellation method, allowing for the generation of three-dimensional digital models of the microstructure that represent the material\u27s internal structure.
The results confirm that based on the basic stereological parameters obtained from two-dimensional cross-sections, three-dimensional reconstruction of the microstructure of polycrystalline zirconia is possible. This work, therefore, represents a step towards the effective design of ceramic materials with high performance parameters, through the control and optimization of their microstructure
Jaka jest przyszłość energetyki rozproszonej? I Kongres Energetyki Rozproszonej, AGH, Kraków, 25 września 2023 r.
Full text linkW artykule omówiono perspektywę rozwoju energetyki rozproszonej (ER) w aspektach geopolityki, technologii, przemysłu, systemu energetycznego, instytucji oraz europejskich wyzwań. Przedstawiono także znaczenie bezpieczeństwa energetycznego w kontekście geopolitycznym oraz rosnącą rolę ER w zabezpieczaniu dostaw energii. Zwrócono uwagę na techniczne wyzwania związane z generacją niesterowalną, a także na konieczność różnicowania źródeł energii oraz rozwoju technologii. W perspektywie przemysłowej uwypukla się potrzeba utrzymania dotychczasowego potencjału Europy i zlokalizowania procesów przemysłowych na jej terenie. Przeanalizowano również kwestie systemowe, w tym zmiany prawodawstwa oraz sposobu zarządzania systemem energetycznym, a także rozwój lokalnych społeczności energetycznych. W kontekście europejskim istotną rolę odgrywają zmiany w unijnych instytucjach oraz miejsce Polski w procesie transformacji energetycznej (TE). Artykuł podkreśla znaczenie współpracy, innowacji oraz społecznego wsparcia dla rozwijającej się energetyki rozproszonej
Microservices, a Definition Analyzed by ßMACH
Full text linkMicroservices are an answer to various scalability challenges. They enable building large and complex systems by scaling the number of services, and development teams. Microservices allow self-management and agile processes such as Scrum. Nevertheless, a minimal management process should also be defined and documented. Documentation must be easily understandable and applicable to the developing teams to foster efficiency. We propose to use the ßMACH method, a software management guidance. The result is a minimal and systematic description. Based on the definition obtained using ßMACH, we can state that the service and team isolation is essential for a scalable microservice system. In addition, we introduce ßMACH and show how to document a software management process. The documentation is easy to understand by software developers and interesting for software engineers