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Decision Making in Manufacturing and Services
No full textThis paper presents a new heuristic algorithm for the task of lot sizing and scheduling for identical parallel machines. The new algorithm is based on the rolling-horizon approach and the fix-and-relax decomposition technique. Two variants of the algorithm are finally proposed for solving the problem of lot scheduling with parallel machines where the number of products and machines is greater than that of the machines. A computational experiment has been conducted for a group of 30 data sets. The results showed that the new algorithm efficiently provided good solutions for tasks with large numbers of machines and products.Krakówwersja wydawnicz
Decision Making in Manufacturing and Services
No full textThe main purpose of the research was to determine the possibilities and experimentally verify the benefits of using thermoplastic materials in a cutless plain bearing. The tested bearings were subjected to equal loads and rotational speeds, using water as the lubricant. Analysis showed that they achieved the best vibration damping at lower speeds, between 600 and 1100 RPM. Comparative studies of bearings made of different materials, such as available on the market bearings made of rubber, bearings printed with a 3D printer from PETG, PLA, ABS or Tribo filament materials, revealed differences in their vibration damping ability and operational stability. Conclusions from the study suggest that higher vibration acceleration may increase the radius of the trajectory, which may affect the function and performance of the bearings. The importance of the operational stability of water-lubricated plain bearings cannot be assessed solely on the basis of the RMS of vibration acceleration or trajectory radius. Both of these parameters are crucial from the user’s point of view, especially in the context of various applications such as electric boats.Krakówwersja wydawnicz
Managerial Economics
No full textBibliogr. s. 127-128.Financial integration has been proven to benefit European economies. However, it may obstruct diversification attempts, and so attracts the attention of investors and researchers. The aim of this paper is to analyze changes in spillovers between European markets, the European Index, and the World Index, over a period of two decades (2000-2021), with regard to the level of development. Mature markets have higher spillovers than emerging and frontier ones. The main finding is that non-developed markets' spillover levels in tranquil periods did not substantially increase in the last two decades, despite ongoing integration with developed European markets. However, spillover rises in time of global or regional crisis (e.g. Great Financial Crisis, Eurozone Debt Crisis, COVID-19 pandemic) for all markets, regardless of economic development, which can undermine diversification attempts just when they are most needed. Afterwards, the transmission of shocks falls back to the pre-crisis level, with the exception of the spillover between Eurozone markets and European Index, which remained very high even after the end of the particular crisis.Krakówwersja wydawnicz
Journal of Casting & Materials Engineering
No full textBibliogr. s. 5-7.High Silicon Strengthened Ductile Iron (HSiSDI) with 4.2 wt.% of silicon was produced in Y-blocks with different thicknesses to investigate the effects of the solidification rate on microstructure integrity and tensile mechanical properties. With decreasing solidification rates, the graphite degeneracy with the appearance of chunky graphite became more significant at the highest silicon contents, so chemical ordering and graphite degeneracy seemed to be qualitative explanations of tensile property degradation. However, a deeper analysis of the relationship between solidification rate, microstructure and tensile properties was realized through an innovative approach based on the Matrix Assessment Diagram (MAD), where the parameters of Voce equation resulting from best-fitting the experimental tensile flow curves of a significant number of HSiSDI samples, were plotted. For 3.5 wt.% silicon content, the MAD analysis indicated that the microstructure was sound for any solidification rate, while for 4.5 wt.% the microstructure was sound only for the fastest solidification rates. For 4.2 wt.% silicon content the MAD analysis pointed out that the tensile plastic behaviour and the microstructure integrity was in between the 3.5 and 4.5 wt.% silicon contents, representing a composition threshold where the reliable microstructures were only found with the fastest solidification rates, while considerable variability was found for the slowest ones. Support to the MAD analysis results was given from microstructure observations.Krakówwersja wydawnicz
Energetyka Rozproszona
No full textStrategia energetyki rozproszonej w Polsce do 2040 roku (SER 2040) jest dokumentem tworzonym w ramach oddolnej inicjatywy wynikającej z celów projektu «Rozwój energetyki rozproszonej w klastrach energii (KlastER)» i nawiązuje do założeń Strategii na rzecz Odpowiedzialnego Rozwoju oraz Polityki energetycznej Polski do 2040 r. (PEP 2040). Przygotowany w okresie 2021-2022 dokument proponuje niezbędne w obszarze energetyki rozproszonej (ER) działania, które wspierają realizację PEP 2040 i wyznaczają ramy transformacji energetycznej w Polsce, jednocześnie uwzględniając najnowsze trendy i wydarzenia, które nastąpiły od momentu przyjęcia PEP 2040. Kluczowym elementem i punktem zwrotnym w procesie prac nad Strategią... było opracowanie analizy SWOT dla ER w obszarach ekonomiczno-finansowym, legislacyjno-regulacyjnym, społeczno-kulturowym i techniczno-technologicznym. Prace przeprowadzono pod nadzorem koordynatorów zespołów roboczych Sieci Kompetencji ds. Energetyki Rozproszonej (SKER). Na podstawie efektów analizy przyjęto, że działania wynikające ze Strategii... powinny być realizowane w trzech głównych obszarach, odpowiadających jej poszczególnym celom: regulacyjnym, technicznym i edukacyjnym.The developed Strategy for distributed energy in Poland until 2040 (SER 2040) is a document created as part of a bottom-up initiative resulting from the objectives of the project «Development of distributed energy in energy clusters (KlastER)». In its assumptions, the document refers to the role of distributed energy resulting both from the Strategy for Responsible Development, and in particular from the Polish Energy Policy until 2040. The document prepared in the period 2021-2022 proposes the necessary measures in the field of distributed energy, supporting the implementation of PEP 2040, setting the framework for the energy transformation in Poland, taking into account the latest trends and events that have taken place since the adoption of PEP 2040. A key element and a turning point in the process of works on the Strategy... was the development of a SWOT analysis of distributed energy in the following areas: economic and financial, legislative and regulatory, socio-cultural and technical and technological. The work was carried out under the supervision of the coordinators of the working groups of the Distributed Energy Competence Network (SKER). On this basis, it was assumed that the actions resulting from the Strategy... should be implemented in three main areas corresponding to its individual goals: regulatory, technical and educational.Krakówwersja wydawnicz
Wprowadzenie do algorytmów
No full textNa okładce: «Nowe wydanie».Bibliografia na stronach 1252-1268. Indeks.Wyd. 7 (1 w PWN) - 13 dodr.XIX, [1], 1300 str. : il.Warszawahttps://www.biblos.pk.edu.pl/ST/2021/01/100000331082/100000331082_Cormen_WprowadzenieDoAlgorytmow.pdfpodręcznikwersja wydawnicz
Journal of Casting & Materials Engineering
No full textBibliogr. s. 31-32.Conventional wound material allows bacterial invasions, trauma and discomfort associated with the changing of the dressing material, and the accumulation of body fluid for wounds with high exudate. However, there is a shift from conventional wound dressing materials to polymeric nanofibers due to their high surface area to volume ratio, high porosity, good pore size distribution, which allows for cell adhesion and proliferation. There is an urgent need to synthesis a biodegradable composite that is resistant to bacterial infection. In this study, an electrospun polylactide (PLA) composite suitable for wound dressing, with enhanced antimicrobial and mechanical properties, was produced. The neat PLA, PLA/CH (10 wt.%), PLA/CH (5 wt.%), PLA/CHS (10 wt.%), PLA/CHS (5 wt.%), PLA/CH (2.5 wt.%) /CHS (2.5 wt.%) and PLA/CH (5 wt.%)/CHS (5 wt.%), were electrospun using 0.14 g/ml solution. Results show that crystallinity (67.6%) of neat PLA declined by 3.8% on the addition of 2.5 wt.% chitin/chitosan with improved hydrophilicity of the composite. The tensile strength of neat PLA (0.3 MPa) increased (0.6 MPa) with 2.5 wt.% chitin/chitosan addition. The slight increase in the glass transition temperature from 75°C for neat PLA to 78°C of the composite fibre, showed improved ductility. The fibres showed little beads, hence suitable for wound dressing. The electrospun mats have good water absorption capacity and strong resistance against Staphylococcus aureus. Good performance was attained at 5 wt.% of chitin, chitosan and hybrid reinforcements. Therefore, a PLA/chitin/chitosan composite is recommended as a wound dressing material.Krakówwersja wydawnicz
Applied Surface Science
No full textTransition metal sulfides have received great attention as electrocatalysts for electrochemical sensors and water electrolysis. In the present study, a facile and rapid chemical conversion route was used for the synthesis of partially and fully converted from tube-like CuS. The morphology of the obtained materials was investigated by scanning electron microscopy (SEM) and transition electron microscopy (TEM), revealing that the complex shape of CuS was maintained after the conversion. Information about phase and elemental composition was obtained by X-ray diffraction (XRD), Raman spectroscopy, X-ray fluorescence spectrometry (XRF), and inductively coupled plasma optical emission spectrometry (ICP-OES). The surface composition was analyzed utilizing X-ray photoelectron spectroscopy (XPS). The results indicated that it was possible to precisely control the contribution of each sulfide by varying precursors ratio. Moreover, the conducted experiments enabled to schematically illustrate the junction and propose a conversion mechanism. The electrochemical behavior of the materials was examined using cyclic voltammetry (CV) in the potential range of biomolecules electrooxidation as well as water splitting. Special attention was devoted to reactions occurring on -modified electrodes in alkaline and neutral media. It was found that the formation of subsequent oxides, their reduction, and the recovery of are diffusion-controlled processes.postprin
Energetyka Rozproszona
No full textBibliogr. s. 17-18.Niniejszy artykuł ilustruje zastosowanie metod SWOT i TOWS do analizy wybranych aspektów funkcjonowania rynku energetyki rozproszonej na potrzeby opracowania Strategii rozwoju energetyki rozproszonej w Polsce. Strategia ma wspierać realizację celów przyjętego przez Radę Ministrów w dniu 02.02.2021 r. dokumentu strategicznego Polityka energetyczna Polski 2040, wdrażającego politykę klimatyczno-energetyczną Unii Europejskiej na terenie Polski. Jednym z głównych założeń tej polityki jest osiągnięcie neutralności klimatycznej w UE do 2050 r. Służy temu wprowadzenie mechanizmów regulacyjnych stymulujących osiąganie kolejnych efektów w najbliższych dziesięcioleciach. Realizacja celów klimatyczno-energetycznych UE na 2030 r. jest kluczowa dla transformacji gospodarki energetycznej w niskoemisyjną.This paper illustrates the application of the SWOT and TOWS methods to analyse selected aspects of distributed energy market functioning for the purpose of developing a Strategy for Development of Distributed Energy in Poland. The strategy is to support the implementation of the objectives of the strategic document Energy Policy of Poland 2040 adopted by the Council of Ministers on 02.02.2021, which implements the European Union climate and energy policy in Poland. One of the main assumptions of this policy is to achieve climate neutrality in the EU by 2050. Achievement of the EU climate and energy targets for 2030 is crucial for the energy transition to a low-carbon economy.Krakówwersja wydawnicz