Browsing by Issue Date, starting with "2023"

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Access status: Open Access ,
Modelowanie tekstury w magnezie i jego stopach podczas procesów przeróbki plastycznej na gorąco
(Wydawnictwa AGH, 2023) Sułkowski, Bartosz
Magnesium alloys are becoming more and more widely used in many applications due to their good mechanical properties and high specific strength. These materials are found to be used in automotive and aviation industries because they reduce vehicles weight, fuel consumption and $CO_{2}$ emissions. At the same time, new fields of application are emerging for the magnesium alloys. For example, they are used in medicine for biodegradable prostheses because of their excellent biocompatibility and adequate corrosion resistance. Another area of the Mg alloys application is in a power industry where they can be used for storage systems of electrical power for fuel cells. Some features of the magnesium alloys limit the scope of their applicability. For example, the anisotropy of mechanical properties limits the plastic processing of these materials. Since magnesium belongs to metals with a hexagonal structure, it is similar to other metals of this type (Zn, Ti, Zr) characterized by a large difference in the values of the critical resolved shear stress for different slip systems. Other examples of the anisotropy include a large difference in diffusion and corrosion rates along specific crystallographic directions. In polycrystalline materials the anisotropy of mechanical properties is even more significant because of the impact on a crystallographic texture of the material. This is especially visible among the magnesium alloys plastically processed, where intense crystallographic texture components are observed. The resulting crystallographic texture reduces the formability of the magnesium alloys and increases the anisotropy of strength and corrosion properties. Mechanisms of the crystallographic texture evolution in the magnesium alloys are still not fully understood and are recently an important subject of research. Knowledge of these mechanisms in hexagonal metals is extremely important due to the need to reduce the strong anisotropy of the mechanical properties. Results of experiments available in the literature provide large amounts of data that allow the formulation of new hypotheses. The hypotheses can be verified using mathematical models and computer simulations allowing even more deep understanding of the phenomena discussed. The monograph presents a new model of the crystallographic texture evolution. The model is based on visco-plastic self-consistent and cellular automaton models. The presented model is a unique approach to the evolution of the crystallographic texture in deformed alloys. It can be successfully used to describe processes occurring in metals during hot plastic processing. The developed model takes into account the values of the critical resolved shear stress for individual slip systems, strengthening parameters and processes of grain nucleation and grain growth. It allows to determine the evolution of the main crystallographic texture components, dislocation density, grain size and their disorientation. Thanks to the presented model it is possible to track continuous and discontinuous dynamic recrystallization. The modeling results were compared with the experimentally obtained data. The use of the presented model will allow for designing new hot deformation schemas of metals with the hexagonal structure by striving to form appropriate components of the crystallographic texture. Moreover, proper selection of the process conditions during plastic processing will reduce the high anisotropy of the mechanical properties of the magnesium alloys.
Access status: Open Access ,
Methodological Aspects of Innovation of Project and Production Businesses
(Wydawnictwa AGH, 2023) Sala, Jolanta; Tańska, Halina
In this chapter the authors present a proposal of selected aspects of methodology for improving individual and team innovation in enterprises. Methodological aspects were reasoned with measurements of the level of innovation by GUS and its causes in Poland. The reasons for the low level of innovation are justified by historical roots, as the seven main points formulated by PTI in 1980, similarly to the 21 postulates of “Solidarity”, accurately reflect the main reasons for Poland’s backwardness in development and, unfortunately, most of them are still valid. These reasons require action on the part of the Polish state, but they should also be used in bottom-up activities of each enterprise after minor interpretation corrections. The chapter focuses on industrial enterprises, because the realities of creativity of engineers and technicians are different from workers in other sectors of the economy. An important determinant of creativity in industrial enterprises with aspirations to design their products and production processes is the set of instruments, in particular CAD/CAM/CAE. Three methodological proposals guarantee a faster and more effective way to creativity and innovativeness of enterprises, although their implementation requires a lot of effort on the part of both employees and their employers. At the same time, they are a prerequisite for acquiring the ability to make strategic innovations in the enterprise. The developed methodological solutions have been tested in practice and constitute an institutional recommendation.
Access status: Open Access ,
Ordovician spatial patterns of climate change inferred from isotope thermometers
(Wydawnictwa AGH, 2023) Ma, Xiao-Li; Fan, Yunxuan
Access status: Open Access ,
Magnetorheological fluids subjected to non-uniform magnetic fields: experimental characterization
(2023) Kubık, Michał; Gołdasz, Janusz; Macháček, Ondřej; Strecker, Zbyněk; Sapiński, Bogdan
Magnetorheological (MR) fluids are suspensions of fine, low-coercivity, high magnetizable particles in a continuous liquid phase. When subjected to magnetic field, the material exhibits a rapid change in the apparent viscosity of several orders of magnitude. This unique capability has been successfully exploited in automotive semi-active suspensions systems or systems for manufacturing high quality optics. In a majority of the existing systems, the rheology of MR fluids is controlled by an external uniform field oriented perpendicularly to the fluid flow direction. In general, it is an inherent feature of MR systems operating in flow, shear or squeeze modes, respectively. There is an experimental evidence that the behavior of MR fluids in the so-called pinch-mode (in which the fluid is subjected to non-uniform magnetic field distributions ) clearly stands out against the remaining three operating modes. With the predecessors, the flow through the channel occurs once a pressure across it exceeds the field-dependent threshold pressure. For comparison, in pinch mode valves the magnetic flux energizes mostly the layers of the materials near the channel walls. The outcome is a change in the channel’s effective diameter achieved solely via material means without changing its geometry. To study the fluid’s unique behavior in the pinch mode, the authors designed a prototype valve assembly and examined several fluid formulations of various particle concentration levels across a wide range of external (velocity, magnetic field density) stimuli in an organized effort to further comprehend the phenomenon. The obtained data indicate that the magnitude of the particular effect does not only depend on the magnitudes of the magnetic stimuli but also on the particle concentration; the smaller the concentration of particles the more pronounced the pitch mode like behavior is. In general, the authors believe that the study may provide guidelines as to the selection of fluid formulations for developing novel valveless actuators utilizing MR fluids operating in pinch mode.
Access status: Open Access ,
The earliest Cretaceous carbonate platform destroyed by volcanism from the Ukrainian/Romanian Carpathians - reconstruction based on microfacies
(Wydawnictwa AGH, 2023) Iwańczuk, Joanna; Krobicki, Michał; Feldman-Olszewska, Anna; Hnyłko, Oleh
Access status: Open Access ,
Artificial neural networks as a tool for supporting a moulding sand control system based on the dependency between selected moulding sand properties
(AGH University Press, 2023) Mrzygłód, Barbara; Jakubski, Jarosław; Opaliński, Andrzej; Regulski, Krzysztof
The article presents the potential for using artificial neural networks to support decisions related to the rebonding of green moulding sand. The basic properties of the moulding sand tested in foundries are discussed, especially compactibility as it gives the most information about the quality of green moulding sand. First, the data that can predict the compactibility value without the need for testing are defined. Next, a method for constructing an artificial neural network is presented and the network model which produced the best results is analysed. Additionally, two applications were designed to allow the investigation results to be searchable by determining the range of values of the moulding sand parameters.
Access status: Open Access ,
On local antimagic total labeling of complete graphs amalgamation
(Wydawnictwa AGH, 2023) Lau, Gee-Choon; Shiu, Wai Chee
Let $G=(V,E)$ be a connected simple graph of order $p$ and size $q$. A graph $G$ is called local antimagic (total) if $G$ admits a local antimagic (total) labeling. A bijection $g:E \to \{1,2,\dots,q\}$ is called a local antimagic labeling of $ if for any two adjacent vertices $u$ and $v$, we have $g^+(u) \ne g^+(v)$, where $g^+(u) = \sum_{e\in E(u)} g(e)$, and $E(u)$ is the set of edges incident to $u$. Similarly, a bijection $f:V(G)\cup E(G)\to \{1,2,\ldots,p+q\}$ is called a local antimagic total labeling of $G$ if for any two adjacent vertices $u$ and $v$, we have $w_{f}(u) \ne w_{f}(v)$, where $w_f(u) = f(u) + \sum_{e\in E(u)} f(e)$. Thus, any local antimagic (total) labeling induces a proper vertex coloring of $G$ if vertex $v$ is assigned the color $g^{+}(v)$ (respectively, $w_{f}(u)$). The local antimagic (total) chromatic number, denoted $\chi_{la}(G)$ (respectively $\chi_{lat}(G)$), is the minimum number of induced colors taken over local antimagic (total) labeling of $G$. In this paper, we determined $\chi_{lat}(G)$ where $G$ is the amalgamation of complete graphs. Consequently, we also obtained the local antimagic (total) chromatic number of the disjoint union of complete graphs, and the join of $K_1$ and amalgamation of complete graphs under various conditions. An application of local antimagic total chromatic number is also given.
Access status: Open Access ,
II Noc Bibliotek w Bibliotece Głównej AGH w Krakowie : wbrew stereotypom
(Akademia Górniczo-Hutnicza, 2023) Forma-Kita, Karolina; Imiołek-Stachura, Karolina
Biblioteka Główna
Access status: Open Access ,
Geological history of the NW Indian Plate Tethyan passive margin in the Salt Range, Pakistan
(Wydawnictwa AGH, 2023) Iqbal, Shahid
Access status: Open Access ,
Nauka – Technika – Technologia : seria wydawnicza AGH. Tom 8
(Wydawnictwa AGH, 2023) Gonet, Andrzej; Ciągała, Joanna; Grzech, Magdalena
Ósmy tom monografii z multidyscyplinarnej serii "Nauka - Technika - Technologia" publikowanej w formule open access. Książka zawiera artykuły dotyczące różnorodnych kierunków badawczych AGH, obejmujące zarówno tradycyjne obszary, takie jak górnictwo i hutnictwo, jak i bardzo nowoczesne obszary IT oraz wszelkie inne specjalności i kierunki prowadzone na Uczelni.
Access status: Open Access ,
Polylactide Used as Filament in 3D Printing – Part 2: TG-DTG, DSC and DRIFT Investigations
(AGH University Press, 2023) Grabowska, Beata; Skowron, Mateusz; Kaczmarska, Karolina
In this second part of the article, we delve deeper into the research area initiated in the first part, focusing on the critical exploration of polylactide (PLA) modification to enhance thermal and mechanical properties in PLA-based materials, building upon the insights obtained from comprehensive structural and thermal analyses utilizing analytical methods such as infrared spectroscopy (FTIR), diffuse reflectance infrared spectroscopy (DRIFT), and thermoanalytical research (DRIFT, TG-DTG). A series of structural and thermal analysis research (TG-DTG, DSC, DRIFT) were performed for samples of polylactide (PLA), which is commonly used in additive technologies as a structural material. In total, four materials were considered, including two containing dyes with different colors, a material made of PLA recyclate and a graphene-modified PLA material. It was noted that PLA material reinforced with graphene phase (GRAFYLON®) retains the best thermal properties (TG-DTG), which results in its wider potential for processing, including further modification and usability in manufacturing vehicle structural elements. Recycled PLA material (ALFA+W) was characterized by a higher melting point (T$_{p}$) by more than 20°C than other samples (DSC analysis), so it can be more useful in the production of structural elements operating and used at elevated temperatures.
Access status: Open Access ,
Zamiast wstępu… Kilka słów o studenckim kole naukowym zarządzanie
(Wydawnictwa AGH, 2023) Styk, Katarzyna
Access status: Open Access ,
Analysis of compressor units – operational issues
(Wydawnictwa AGH, 2023) Kurdziel, Franciszek; Pytel, Krzysztof; Kalwar, Adam; Grzywnowicz, Grzegorz; Zdobytskyi, Andriy
The characteristics of compressor chiller operation for the generation of cooling for the central systems of mine air-conditioning installations are presented. The modes of operation of the units and their use in the final stage of chilled-water cooling are described. The construction of the screw compressor and the compression methods are discussed. The actual use of compressors in the third stage of chilled water generation is analyzed. The free-cooling installation as a solution for supporting chilled-water generation is presented.
Access status: Open Access ,
Kazimierz Wiśniak teatralny i piwniczny : wystawa w Archiwum Nauki PAN i PAU w Krakowie (24 kwietnia - 31 sierpnia 2023)
(Akademia Górniczo-Hutnicza, 2023) Laskosz, Joanna; Sieński, Hieronim
Biblioteka Główna
Access status: Metadata only ,
Przestrzeń (do) uczenia się
(2023) Chrząszcz, Agnieszka
Centrum e-Learningu i Innowacyjnej Dydaktyki
Z nagrania dowiesz się: czym są afordancje, jaki wpływ ma przestrzeń fizyczna na proces uczenia się, o teoriach i badaniach nt. przestrzeni (do) uczenia się, o środkach zaradczych.
Access status: Open Access ,
The business model for access to affordable RE on economic, social, and environmental value - a review
(Wydawnictwa AGH, 2023) Erdiwansyah, Erdiwansyah; Gani, Asri; Mamat, Rizalman; Nizar, Muhammad; Yana, Syaifuddin; Rosdi, S. M.; Zaki, Muhammad; Sardjono, Ratnaningsih Eko
Renewable energy has the potential to power the global economy and effective business models will significantly aid this goal, being among the most critical factors in spurring expansion in the energy industry. This paper reviews articles that discuss business models in the renewable energy sector. Longterm economic, social, and ecological stability is concerned. Previous studies have neglected the environmental sustainability of renewable energy business models, focusing on their technical, social, and economic aspects, primarily for energy access. The business models for solar home and pico systems relied heavily on lowering costs through creative payment plans for customers to be commercially viable. The demand for mini-grids requires end users to launch businesses that can leverage electrification initiatives to be commercially viable. The success of a mini-grid depends on the average consumption and revenue per user. Affordability, unmet energy needs, low electricity demand, lack of financing, unfamiliar business models, and immature markets have impeded energy access in Indonesia. Our analysis revealed that future studies in this field must include environmental sustainability to provide a complete picture for decision-makers. Renewable energy needs in Indonesia can be achieved through the sustainability domain, policy makers can consult this evidence set.
Access status: Open Access ,
Wielowymiarowość przestrzeni w bibliotece naukowej XXI wieku
(Wydawnictwa AGH, 2023) Babik, Wiesław
Biblioteka Główna
Celem artykułu jest identyfikacja, opis i interpretacja różnych przestrzeni, w ramach których funkcjonuje współczesna biblioteka naukowa. Identyfikacji i opisu tych przestrzeni dokonano za pomocą analizy i krytyki piśmiennictwa oraz metodą obserwacji. Ustalono, że współczesna biblioteka akademicka charakteryzuje się różnorodnością przestrzeni, w których funkcjonuje. Przeprowadzone badania i analiza pozwoliły na wieloaspektowe spojrzenie na bibliotekę akademicką i przedstawienie jej w postaci wielowymiarowej struktury. Egzemplifikacji dokonano na przykładzie Biblioteki Głównej Akademii Górniczo-Hutniczej w Krakowie.
Access status: Open Access ,
On graph models in knowledge engineering
(Wydawnictwa AGH, 2023) Ligęza, Antoni; Adrian, Weronika Teresa; Adrian, Marek; Kluza, Krzysztof; Jobczyk, Krystian; Wiśniewski, Piotr; Ślażyński, Mateusz; Jemioło, Paweł; Sepioło, Dominik; Stachura-Terlecka, Bernadetta; Zaremba, Mateusz; Szymkowski, Mateusz; Suchenia, Anna; Potempa, Tomasz
The paper presents selected applications of graph models in knowledge engineering. Starting from the basic definition of a graph as a set of nodes connected by edges, the article presents possible extensions of this concept aimed at increasing the power of expression and the ability to process knowledge. In particular, the work focuses on selected applications of graph models in research areas explored by the members of the KRaKEn research team.
Access status: Open Access ,
Geodynamics of Sibumasu Block in Southern Thailand: Interpretation from Heat Flow Map
(Wydawnictwa AGH, 2023) Kongpet, Panupong; Kanjanapayont, Pitsanupong
Access status: Open Access ,
Nowe podejście do oceny trwałości eksploatacyjnej lin stalowych
(Wydawnictwa AGH, 2023) Olszyna, Grzegorz; Rokita, Tomasz; Tytko, Andrzej
Problematyka przyszłego przewidywania stanu technicznego lin w czasie ich eksploatacji jest bardzo istotnym zagadnieniem związanym z bezpieczeństwem użytkowania i obsługi urządzeń. Liny stalowe jako elementy nośne podlegają procesom degradacji przez różnego rodzaju formy zużycia w procesie eksploatacji. Zmienne obciążenia powodują złożony stan naprężeń w drutach, co przekłada się na różne naprężenia rozciągające, skręcające czy naciski powierzchniowe pomiędzy drutami. Liny również narażone są na trudne warunki pracy, np. środowisko korozyjne, zużycie zmęczeniowe, co prowadzi w konsekwencji do osłabienia ich własności użytkowych. Liny jako elementy odpowiedzialne wymagają dokładnego, a zarazem prostego sposobu prognozowania ich bezawaryjnej pracy w prosty i jednoznaczny sposób. Niniejszy artykuł dotyczy zagadnień nowego podejścia do wyznaczania trwałości zmęczeniowej lin stalowych. Tematyka bezpieczeństwa na temat lin stalowych od wielu lat jest zagadnieniem trudnym i niejednoznacznym do wyznaczenia, nie znając trwałości zmęczeniowej obiektu. W artykule omówiono metody doświadczalne i praktyczne do wyznaczania trwałości zmęczeniowej lin stalowych.