Browsing by Issue Date, starting with "2018"

Now showing 1 - 20 of 361

Access status: Open Access ,
Lease as form of municipal land management - case study
(Wydawnictwa AGH, 2018) Trojanek, Maria
This paper presents information about different forms of land management, especially land leasing. Land lease transactions in Poznan, one of Poland's regional cities, have been analyzed. The research has shown that, in Poland, long-term leases have been used in a very limited (partial) scope so far. Most often, lease agreements are concluded for up to three years with the possibility of extension, although the law provides for the possibility of concluding contracts for longer periods. During the years of 1996-2014, the city of Poznan concluded only 18 long-term lease agreements, which is caused by the dominant form of managing public lands - perpetual usufruct.
Access status: Open Access ,
Innowacyjne rozwiązania maszyn górniczych opracowane w Katedrze Maszyn Górniczych, Przeróbczych i Transportowych Akademii Górniczo-Hutniczej
(Wydawnictwa AGH, 2018) Krauze, Krzysztof; Kotwica, Krzysztof
Eksploatacja surowców mineralnych metodami podziemnymi staje się coraz trudniejsza ze względu na warunki górniczo-geologiczne, w jakich te surowce zalegają. Wiąże się to z głębokością zalegania i miąższością eksploatowanych pokładów, trudniej urabialnymi skałami oraz warunkami klimatycznymi. Drążenie wyrobisk udostępniających i przygotowawczych, a także prowadzenie eksploatacji w takich warunkach wymaga specjalnie do tego opracowanych i wykonanych maszyn. W Katedrze Maszyn Górniczych, Przeróbczych i Transportowych AGH w Krakowie w ostatnich latach opracowano szereg innowacyjnych rozwiązań, które mogą być zastosowane do maszyn i urządzeń pracujących w ciężkich warunkach górniczo-geologicznych. W niniejszym artykule przedstawiono wybrane rozwiązania: głowicę z narzędziami dyskowymi niesymetrycznymi o złożonej trajektorii ruchu dla kombajnów chodnikowych, tymczasową, zmechanizowaną i kroczącą obudowę chodnikową, unikalny kompleks ścianowy dla niskich pokładów z kombajnem węglowym jednoorganowym oraz innowacyjny układ urabiania i odstawy do mechanicznego drążenia szybów z wykorzystaniem kombajnów szybowych.
Access status: Open Access ,
Emission of pollutants into the air during exploration of coalbed methane
(Wydawnictwa AGH, 2018) Łukańko, Łukasz; Macuda, Jan
Coalbed methane is usually utilized by gas well drilled from the surface. In order to increase the coefficient of methane exploration from coal seams, in a horizontal section of the well, hydraulic fracturing operations are applied. Drilling process and hydraulic fracturing operations involve emission of pollutants to the air from the fuel combustion process. In the case of drilling operations fuel is used to generate electric power, which drives the drilling device and its components, while during hydraulic fracturing to drive high-pressure pump engines.
Access status: Open Access ,
An efficient approach for view selection for data warehouse using tree mining and evolutionary computation
(Wydawnictwa AGH, 2018) Thakare, Atul; Deshpande, Parag
The selection of a proper set of views to materialize plays an important role in database performance. There are many methods of view selection that use different techniques and frameworks to select an efficient set of views for materialization. In this paper, we present a new efficient scalable method for view selection under the given storage constraints using a tree mining approach and evolutionary optimization. The tree mining algorithm is designed to determine the exact frequency of (sub)queries in the historical SQL dataset. The Query Cost model achieves the objective of maximizing the performance benefits from the final view set that is derived from the frequent view set given by the tree mining algorithm. The performance benefit of a query is defined as a function of query frequency, query creation cost, and query maintenance cost. The experimental results show that the proposed method is successful in recommending a solution that is fairly close to an optimal solution.
Access status: Open Access ,
Urabianie cienkich pokładów węgla kamiennego metodami powierzchniowo-podziemnymi
(Wydawnictwa AGH, 2018) Bołoz, Łukasz
Złoża węgla kamiennego zalegające płytko w postaci pokładów można eksploatować metodami powierzchniowo-podziemnymi. Są to metody charakteryzujące się eksploatacją złoża z powierzchni, jednak sam proces urabiania odbywa się pod ziemią. Duże zróżnicowanie warunków górniczo-geologicznych było przyczyną powstania wielu metod i systemów eksploatacji oraz maszyn, stosowanych czasami jedynie lokalnie w różnych zakątkach świata. Przedstawiono stosowane na świecie metody powierzchniowo-podziemne. Zwrócono uwagę na nietypowe i rzadko stosowane metody oraz maszyny, które z różnych względów nie występują w Polsce. Omówiono maszyny urabiające, pracujące w metodach highwall mining, auger mining, a także punch longwall mining wraz z ich odmianami i typami.
Access status: Open Access ,
Profesor Tadeusz Haupt : tablice – pamięć wiecznie żywa
(Akademia Górniczo-Hutnicza, 2018) Sieński, Hieronim
Biblioteka Główna
Access status: Open Access ,
Comparative analysis of heating, ventilation and electricity costs on the example of residential building in the near zero-energy standard
(Wydawnictwa AGH, 2018) Krajewska, Małgorzata; Szopińska, Kinga
This article deals with an analysis of the operating costs of a building designed in the »near zero-energy« standard, with various technological solutions for heating and ventilation supported by a photovoltaic system (three technological variants). Following the analysis, a technological variant using an economic criterion based on the minimization of annual operating costs was selected.
Access status: Open Access ,
Positive thinking – a universal cure for modern-day diseases?
(Wydawnictwa AGH, 2018) Butmanowicz-Dębicka, Iwona
In this article, I analyse features of positive thinking which have made this ideological trend come to be a perceived as a panacea for the whole spectrum of shortcomings felt by many modern people and, in their conviction, are blocking their ability to succeed and enjoy life. Most therapies and self-improvement techniques offered are now deeply embedded in modern reality and, irrespective of their intellectual level, proven results or magical atmosphere, are highly popular. Therefore, we should ask why this has happened, i.e. what do individual positive thinking schools actually offer? In this article I present concepts which lead to answer this question.
Access status: Open Access ,
Innovative mining machinery solutions developed at Department of Mining, Dressing, and Transport Machines, AGH University of Science and Technology
(Wydawnictwa AGH, 2018) Krauze, Krzysztof; Kotwica, Krzysztof
The exploitation of mineral resources with underground mining methods is becoming more and more difficult due to the mining and geological conditions in which these resources are present. This is related to the depth of retention and thickness of the exploited deposits (seams), more cohesive and durable rocks, and climatic conditions. The excavation of access and preparatory roadways as well as exploitation under such conditions require specially designed and manufactured machines. In recent years in the Department of Mining, Dressing, and Transport Machine at AGH University of Science and Technology in Krakow, a number of innovative solutions of machines and devices have been developed that can be used to work under difficult mining and geological conditions. This article presents selected solutions of these machines and devices - a mining head for a roadheader with asymmetrical disc tools with a complex motion trajectory, a temporary, mechanized, and walking roadway support, a unique longwall complex with a single-cutting head shearer used for thin coal seam exploitation, and an innovative mining and hauling system for mechanical shaft drilling using a shaft shearer.
Access status: Open Access ,
Badania sprawności ładowania frezującym organem ślimakowym przy nachyleniu podłużnym wyrobiska ścianowego
(Wydawnictwa AGH, 2018) Wydro, Tomasz
W artykule przedstawiono realizacje oraz wyniki badań sprawności ładowania frezującymi organami ślimakowymi w funkcji nachylenia wyrobiska ścianowego. Badania zostały przeprowadzone przy różnych kątach nachylenia podłużnego wyrobiska ścianowego w zakresie od 0° do 9° po wzniosie. W warunkach rzeczywistych rozdzielenie dwóch podstawowych procesów, jakie zachodzą podczas pracy kombajnu ścianowego, czyli frezowania i ładowania nie jest możliwe, w związku z tym badania zostały przeprowadzone w warunkach laboratoryjnych w Katedrze Maszyn Górniczych, Przeróbczych i Transportowych Akademii Górniczo-Hutniczej w Krakowie. Badania wykonano na specjalnym stanowisku pozwalającym na skokową zmianę nachylenia podłużnego i poprzecznego wyrobiska ścianowego. Na podstawie ich wyników stwierdzono, że nachylenie wyrobiska ścianowego wpływa na sprawność ładowania, co oznacza, że wraz ze wzrostem kąta nachylenia podłużnego opory ładowania rosną, a sprawność ładowania maleje.
Access status: Open Access ,
Kraków był pierwszy... : w stulecie odzyskania niepodległości
(Akademia Górniczo-Hutnicza, 2018) Sieński, Hieronim
Biblioteka Główna
Access status: Open Access ,
Analiza naprężeń i odkształceń zębów tnących koparki wielonaczyniowej w trakcie pracy z wykorzystaniem metody elementów skończonych (MES)
(Wydawnictwa AGH, 2018) Kertész Brînaş, Ildiko; Rebedea, Narcis Ionel; Oltean, Ilie Luciano
W przypadku koparek wielonaczyniowych na proces urabiania mają wpływ siły przeciwstawne elementów roboczych i narzędzi urabiających. Siły te determinują wybór maszyn i ich parametrów oraz metody działania [1, 2]. Badania nad przyczynami awarii części mechanicznych pokazują, że systemy urabiania i ładowania powodują najwięcej awarii, około 32 wszystkich odnotowanych awarii mechanicznych [3]. W niniejszej pracy będziemy używać metody elementów skończonych (MES) do analizy odkształceń i naprężeń działających na ząb tnący, zamocowany na kole czerpakowym koparek wielonaczyniowych. W tym celu wykorzystano oprogramowanie SolidWorks® - zarówno jako narzędzie CAD do projektowania zęba, jak i do modelowania oraz symulacji zjawisk.
Access status: Open Access ,
Descriptive representation about transformation of company by using current technologies and tools for analytical processing and evaluation of diverse data
(Wydawnictwa AGH, 2018) Koman, Gabriel; Holubčík, Martin|Kubina, Milan
Companies are currently producing and processing larger and larger amounts of data that they were not able to effectively process and subsequently use in the management of company processes in the past. There are several technologies and tools for the analytical processing and evaluation of diverse data, such as the Big Data technology. The Industry 4.0 concept (which is closely linked with the IoT) will bring an enormous growth of produced data into the company sphere. The information value of such data can significantly affect managing and decision-making processes in a company. Here, we can see a synergy between man and technology where each influences the other. The purpose of this paper is to support the following statement: in the present business environment, we are facing the transformation of a company that, for efficient management and decision-making, needs: a) to capture and process all available data, b) to implement new tools into strategic decisions, and c) to integrate data through a single system. This article describes the possibilities of deploying the efficient use of new technologies (Big Data, Industry 4.0, and IoT) in management.
Access status: Open Access ,
Rozprawy online
(Akademia Górniczo-Hutnicza, 2018) Chwastek, Agata
Biblioteka Główna
Access status: Open Access ,
Machine learning models for predicting patients survival after liver transplantation
(Wydawnictwa AGH, 2018) Jarmulski, Wojciech; Wieczorkowska, Alicja; Trzaska, Mariusz; Ciszek, Michał; Paczek, Leszek
In our work, we have built models predicting whether a patient will lose an organ after a liver transplant within a specified time horizon. We have used the observations of bilirubin and creatinine in the whole first year after the transplantation to derive predictors, capturing not only their static value but also their variability. Our models indeed have a predictive power that proves the value of incorporating variability of biochemical measurements, and it is the first contribution of our paper. As the second contribution we have identified that full-complexity models such as random forests and gradient boosting lack sufficient interpretability despite having the best predictive power, which is important in medicine. We have found that generalized additive models (GAM) provide the desired interpretability, and their predictive power is closer to the predictions of full-complexity models than to the predictions of simple linear models.
Access status: Open Access ,
Non-invasive analysis and visualization of objects from FSW AlSi9Mg/2017A aluminum alloy joints
(Wydawnictwa AGH, 2018) Wójcicka, Anna; Mroczka, Krzysztof; Kowalski, Marcin
Friction stir welding (FSW) technology allows for the welding of materials that differ in their chemical compositions, microstructures, and properties. When selecting the parameters, it is necessary to analyze the structure of a weld and eliminate the defects. The use of X-ray microtomography creates the possibility of precise imaging of a joint structure - especially when it contains defects (voids). The tests were carried out on an FSW joint made with both 2017A and AlSi9Mg aluminum alloys. The macrostructure was cross-sectional, and a defect was found in the middle part of the joint and on the advancing side. We used a conventional method of observation light microscopy. Then, an analysis was performed using X-ray microtomography, which revealed the shape of the defect in 3D. Individual cross-sections were extracted, which enabled us to measure the geometric quantities. A dependence was found for the shape of the defect on the welding parameters and the variability of its construction. The usefulness of this advanced material imaging technology for the analysis of FSW welds has been confirmed.
Access status: Open Access ,
Theoretical and practical aspects of estimation of forced sale value
(Wydawnictwa AGH, 2018) Šabeka, Vladimir Leonidovič
This paper deals with the key categories used in the procedure of estimating the forced sale value of an object. We consider the different criteria and provide methodological recommendations on the classification of various objects of civil rights as objects of valuation. Materials of expert assessments and empirical observations are presented. A practice-oriented model for estimating liquidation value is proposed.
Access status: Open Access ,
The content and composition of organic matter in bottom sediments of the Rybnik reservoir - preliminary studies
(Wydawnictwa AGH, 2018) Baran, Agnieszka; Mierzwa-Hersztek, Monika; Gondek, Krzysztof; Szara, Magdalena; Tarnawski, Marek
Organic matter has important influences on the fate of environmental pollution in water dam reservoirs. The aim of the studies was to assess content of organic matter fractions in Rybnik reservoir bottom sediments, and to determine their influence on the content of heavy metals and PAHs. In three sediment samples, the content of C organic (Corg), C extracted (Cex), C humic acid (Cha), C fulvic acid (Cfa) and C non-hydrolyzed (Cnh), buffer capacity, and content of heavy metals and PAHs was analyzed. We found the highest content of Corg, Cex, Cha, Cfa and Cnh in sample 3 (the outlet, near the dam), while the lowest content was found in sample 2 (middle). The fraction of Cnh was dominant in sediment sample 3 (outlet, near dam) and 1 (inlet), whereas the fraction of Cha dominated in sample 2 (middle). Rybnik bottom sediments are characterized by their high buffer capacities (samples 3, 1) shaped among others by the high content of organic matter. The high organic matter content in samples 3 (outlet) and 1 (inlet) and also high total contents of heavy metals and PAHs in these sediments demonstrate that these pollutants have a strong affinity for organic matter in the sediments. Moreover, the highest mobility of metals, from sample 2 (middle), is connected with the low content of organic matter substances and the low buffer capacities of sediments.
Access status: Open Access ,
Small-gain theorem for a class of abstract parabolic systems
(Wydawnictwa AGH, 2018) Grabowski, Piotr
We consider a class of abstract control system of parabolic type with observation which the state, input and output spaces are Hilbert spaces. The state space operator is assumed to generate a linear exponentially stable analytic semigroup. An observation and control action are allowed to be described by unbounded operators. It is assumed that the observation operator is admissible but the control operator may be not. Such a system is controlled in a feedback loop by a controller with static characteristic being a globally Lipschitz map from the space of outputs into the space of controls. Our main interest is to obtain a perturbation theorem of the small-gain-type which guarantees that null equilibrium of the closed-loop system will be globally asymptotically stable in Lyapunov's sense.
Access status: Open Access ,
Microstructural characterization and mechanical behavior of copper matrix composites reinforced by B4C and sea shell powder
(AGH University of Science and Technology Press, 2018) Sankar, Mathiazhagan; Pushpanathan, D. Peter; Myszka, Dawid; Devaneyan, Pradeep S.
This paper investigates the microstructural and mechanical properties of copper metal matrix composites reinforced with B$_{4}$C and crushed sea shell particles (fabricated using powder metallurgy). In powder form, copper is widely used in structural applications. Copper also possesses very good electrical and thermal conductivity, ductility, and corrosion resistance. B$_{4}$C is the third-hardest-known material that also possesses excellent toughness and wear resistance. Sea shells are readily available along coastal areas. Therefore, an attempt has been made in this work to investigate the feasibility of its utilization in powder metallurgy. Two batches of samples were prepared. In the first batch, the percentage of boron carbide and copper powder were varied, and seashell powder was not included. In the second batch, the percentages of B$_{4}$C, copper, and sea shell powder were varied in order to assess the change effected by the sea shell material. The sintered samples of both batches were subjected to microstructural characterization to ascertain the homogeneous distribution of the reinforcements. The microhardness and wear resistance of all of the fabricated samples were assessed. The results confirmed that the inclusion of 2% sea shell powder (by weight) with 10% boron carbide improved the wear resistance and hardness of the composite.