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Gdańsk University of Technology

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Publications from the year 2020

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  • Spirala 2 (wg Ulama) z cyklu No Quick Response
    • Krzysztof Wróblewski
    2020

    Spirala 2 (wg Stanisława Ulama) Obraz odnosi się do modelu matematycznego nazywanego Spiralą Ulama, który polega na okrężnym zapisie w polu kwadratu liczb naturalnych od 1 do nieskończoności. Taki zapis uwidacznia szczególne wzory, które powstają z położenia liczb pierwszych (niepodzielnych). Liczby pierwsze tworzą ciągi mniej lub bardziej regularne w układzie diagonalnym, poziomym i pionowym. W obrazie Spirala 2 wykorzystany został zestaw liczb od 1 do 1600. Położenia liczb pierwszych są malowane czernią i bielą, natomiast położenie pozostałych liczb kolorami podstawowymi i pochodnymi w różnej tonacji. Kolory "wędrują" progresywnie za liczbami po kształcie spirali. Sekwencyjny rytm przerywany jest położeniem liczby pierwszej. W wyniku tego zabiegu samorzutnie powstają grupy różnych form i kolorów, przy czym żadna z nich nie jest dominująca w całości układu. Poszczególne kształty są tylko cząstkami większej całości. W spirali Ulama podobnie jak w ciągu Fibonacciego występuje rodzaj harmonijnej jedności. Krzysztof Wróblewski

  • Społeczna odpowiedzialność biznesu w branży odzieżowej - perspektywa polskiego konsumenta
    • Ewa Marjańska
    • Piotr Grudowski
    • Anna Wendt
    • Mateusz Muchlado
    2020 Problemy Jakości

    Przesunięcie produkcji do krajów dotkniętych ubóstwem towarzyszy podejściu kładącemu nacisk na szybkie odpowiedzialność i tanie udostępnianie trendów modowych konsumentom oraz systemowi wytwarzania opartemu na popycie biznesu, w przemyśle odzieżowym. W artykule zwrócono uwagę na: świadomość, postawy, zachowania etyczne oraz zrównoważony sposób postrzegania jakości produktów „fast fashion” w perspektywie społecznej odpowiedzialności. Na rozwój, podstawie metody CAWI i PAPI przeprowadzono badanie polskich konsumentów deklarujących zachowania przemysł odzieżowy, nabywcze związane z „fast fashion”. Badania wykazały, że działania związane ze społeczną odpowiedzialnością fast fashion biznesu w branży odzieżowej są istotne dla klientów, jednak cena jest najważniejszym czynnikiem przy podejmowaniu decyzji o zakupie. Ocena świadomości konsumentów w zakresie CSR może posłużyć do ukierunkowania przyszłych działań edukacyjnych w tym obszarze, zwłaszcza w dobie przyspieszonej konsumpcji i celów zrównoważonego rozwoju. Wyniki badań mogą też być przesłanką do określenia kierunku działań związanych z CSR dla sprzedawców „fast fashion”.

  • Społeczna odpowiedzialność biznesu w kontekście strategii wybranych spółek posiadających istotne znaczenie dla gospodarki
    • Sebastian Skuza
    • Anna Modzelewska
    • Malwina Popiołek
    • Marta Szeluga-Romańska
    2020

    Przedmiotem badań jest analiza sposobów realizacji strategii społecznej odpowiedzialności biznesu przez przez wybrane spółki z udziałem Skarbu Państwa.

  • Stability analysis of interconnected discrete-time fractional-order LTI state-space systems
    • Łukasz Grzymkowski
    • Damian Trofimowicz
    • Tomasz Stefański
    2020 Full text International Journal of Applied Mathematics and Computer Science

    In this paper, a stability analysis of interconnected discrete-time fractional-order (FO) linear time-invariant (LTI) state-space systems is presented. A new system is formed by interconnecting given FO systems using cascade, feedback, parallel interconnections. The stability requirement for such a system is that all zeros of a non-polynomial characteristic equation must be within the unit circle on the complex z-plane. The obtained theoretical results lead to a numerical test for stability evaluation of interconnected FO systems. It is based on modern root-finding techniques on the complex plane employing triangulation of the unit circle and Cauchy’s argument principle. The developed numerical test is simple, intuitive and can be applied to a variety of systems. Furthermore, because it evaluates the function related to the characteristic equation on the complex plane, it does not require computation of state-matrix eigenvalues. The obtained numerical results confirm the efficiency of the developed test for the stability analysis of interconnected discrete-time FO LTI state-space systems.

  • Stability analysis of nanobeams in hygrothermal environment based on a nonlocal strain gradient Timoshenko beam model under nonlinear thermal field
    • Subrat Kumar Jena
    • S. Chakraverty
    • Mohammad Malikan
    2020 Full text Journal of Machinery Manufacture and Reliability

    This article is dedicated to analyzing the buckling behavior of nanobeam subjected to hygrothermal environments based on the principle of the Timoshenko beam theory. The hygroscopic environment has been considered as a linear stress field model, while the thermal environment is assumed to be a nonlinear stress field based on the Murnaghan model. The size-dependent effect of the nanobeam is captured by the nonlocal strain gradient theory (NSGT), and the governing equations of the proposed model have been derived by implementing a variational principle. The critical buckling loads have been calculated for the hinged–hinged boundary condition by incorporating the Navier approach and considering other elasticity theories such as classical elasticity theory, Eringen nonlocal elasticity theory, and strain gradient theory along with the NSGT. The present model is also validated with the pre-existing model in exceptional cases. Further, a parametric investigation has been performed to report the influence of various scaling parameters like hygroscopic environment, thermal environment, length-to-diameter ratio, small scale parameter, and length scale parameter on critical buckling loads by considering both the linear and nonlinear temperature distributions.

  • Stabilizing lactate production through repeated batch fermentation of food waste and waste activated sludge
    • Xianbao Xu
    • Wenjuan Zhang
    • Xia Gu
    • Zhichao Guo
    • Jian Song
    • Daan Zhu
    • Yanbiao Liu
    • Yanan Liu
    • Gang Xue
    • Xiang Li
    • Jacek Mąkinia
    2020 BIORESOURCE TECHNOLOGY

    Bio-valorization of organic waste streams, such as food waste and waste activated sludge, to lactic acid (LA) has recently drawn much attention. It offers an opportunity for resource recovery, alleviates environmental issues and potentially turns a profit. In this study, both stable and high LA yield (0.72 ± 0.15 g/g total chemical oxygen demand) and productivity rate (0.53 g/L•h) were obtained through repeated batch fermentation. Moreover, stable solubilization and increase in the critical hydrolase activities were achieved. Depletions of ammonia and phosphorus were correlated with the LA production. The relative abundance of the key LA bacteria genera (i.e., Alkaliphilus, Dysgonomonas, Enterococcus and Bifidobacterium) stabilized in the repeated batch reactor at a higher level (44.5 ± 2.53%) in comparison with the batch reactor (26.2 ± 4.74%). This work show a practical way for the sustainable valorization of organic wastes to LA by applying the repeated batch mode during biological treatment.

  • Standardy Profesjonalnego Public Relations
    • Jacek Barlik
    • Ewa Hope
    • Jerzy Olędzki
    • Krystyna Wojcik
    2020

    " Standardy przedstawiają wartości i pryncypia uzasadniające konieczność dokonywania odpowiednich wyborów. Public relations ma godzić interesy zleceniodawców, przedstawicieli mediów i różnych grup społeczeństwa, a przy tym pozostawać w zgodzie z normami etycznymi i odwoływać się do takich wartości jak szacunek, godność, rzetelność, uczciwość, prawda, wiarygodność, niezależność, lojalność i zaufanie. Opracowanie "Standardów profesjonalnego Public Relations" zostało przygotowane przez społeczny zespół ekspertów - autorzy dokumentu, w przekonaniu, że profesjonalizm i etyka są ze sobą nierozerwalnie połączone -zwłaszcza w dziedzinach, które - jak PR, wpływają na kondycję społeczeństwa."

  • Stanowisko laboratoryjne do badania procesów wibroakustycznych w rejonie głowicy cylindrowej silnika z zapłonem samoczynnym - wyniki badań pilotażowych
    • Jacek Rudnicki
    2020 Full text Journal of Polish CIMEEAC

    W artykule przedstawiono założenia oraz ich praktyczną realizację w odniesieniu do stanowiska laboratoryjnego przeznaczonego do badania procesów wibroakustycznych w rejonie głowicy silnika z zapłonem samoczynnym. Podstawowym założeniem podczas realizacji tego projektu było stworzenie możliwości dydaktycznych oraz naukowo – badawczych w zakresie obserwacji i rejestracji procesów drganiowych w rejonie głowicy cylindrowej silnika z zapłonem samoczynnym podczas pracy układu rozrządu napędzane go ze źródła zewnętrznego. Umożliwia to wyselekcjonowanie prawie „czystej” postaci tych procesów, pochodzących wyłącznie od pracy układu rozrządu bez zakłóceń spowodowanych pracą innych przekładni i mechanizmów w rzeczywistym silniku oraz zjawisk gazodynamicznych związanych ze spalaniem. Fakt ten pozwala na rejestrację wartości wybranych wskaźników opisujących drgania tego węzła konstrukcyjnego silnika, odpowiednie opracowanie powstałych zapisów i ich ewentualne wykorzystanie we wnioskowaniu diagnostycznym np. w zakresie oceny faz rozrządu. Innym sposobem wykorzystania tak uzyskanych wyników jest możliwość wykorzystania tych zapisów do filtracji wyników uzyskanych na obiekcie rzeczywistym czyli funkcjonującym silniku.

  • Stanowisko wizualizacji zdarzeń w systemie STRADAR – realizacja i funkcje dla operatora
    • Bartosz Czaplewski
    • Sylwester Kaczmarek
    • Jacek Litka
    2020 Full text Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    It is crucial for the Border Guard to be equipped with a communication-teleinformatic infrastructure designed to support them in efficient realization of their operational tasks. STRADAR – a system which results are presented in this paper – is such an infrastructure. It is a distributed solution for the maritime division of the border guard. The system, with the use of a network of sensors located in both stationary and mobile points collects, archives and processes information and multimedia data, which can be made available to the staff on their demand. STRADAR consists of a number of functional elements. The paper includes a detailed description of one of them. This element being Event Visualization Post EVP, which utilizes multidisplay set up in the Centrum, to display multimedia presentation of information and data for both archival and current situations.

  • Static and Dynamic Mechanical Properties of 3D Printed ABS as a Function of Raster Angle
    • Mateusz Galeja
    • Aleksander Hejna
    • Paulina Kosmela
    • Arkadiusz Kulawik
    2020 Full text Materials

    Due to the rapid growth of 3D printing popularity, including fused deposition modeling (FDM), as one of the most common technologies, the proper understanding of the process and influence of its parameters on resulting products is crucial for its development. One of the most crucial parameters of FDM printing is the raster angle and mutual arrangement of the following filament layers. Presented research work aims to evaluate different raster angles (45°, 55°, 55’°, 60° and 90°) on the static, as well as rarely investigated, dynamic mechanical properties of 3D printed acrylonitrile butadiene styrene (ABS) materials. Configuration named 55’° was based on the optimal winding angle in filament-wound pipes, which provides them exceptional mechanical performance and durability. Also in the case of 3D printed samples, it resulted in the best impact strength, comparing to other raster angles, despite relatively weaker tensile performance. Interestingly, all 3D printed samples showed surprisingly high values of impact strength considering their calculated brittleness, which provides new insights into understanding the mechanical performance of 3D printed structures. Simultaneously, it proves that, despite extensive research works related to FDM technology, there is still a lot of investigation required for a proper understanding of this process.

  • Step on It Bringing Fullwave Finite-Element Microwave Filter Design up to Speed
    • Łukasz Balewski
    • Grzegorz Fotyga
    • Adam Lamęcki
    • Michał Mrozowski
    • Martyna Mul
    • Piotr Sypek
    • Damian Szypulski
    2020 Full text IEEE MICROWAVE MAGAZINE

    There are many steps in the design of a microwave filter: mathematically describing the filter characteristics, representing the circuit as a network of lumped elements or as a coupling matrix, implementing the distributed elements, finding the initial dimensions of the physical structure, and carrying out numerical tuning using electromagnetic (EM) simulators. The whole process is painstaking and time-consuming, and it requires a great deal of engineering expertise. Microwave filters are extremely complex geometric structures, and their simple circuits are often quite hard to represent. Moreover, manufacturing them is costly: to be sure that the hardware resulting from the design will meet the performance goals, rigorous computer tools are used to determine the physical dimensions and evaluate all of the adjustments at the final stage. This last stage is particularly challenging, and advanced computational techniques are required.

  • Storage electric multiple units on partially electrified suburban railway lines
    • Aleksander Jakubowski
    • Natalia Karkosińska-Brzozowska
    • Krzysztof Karwowski
    • Andrzej Wilk
    2020 Full text Przegląd Elektrotechniczny

    The paper presents possible environmental, energy and economical gains implied by replacing conventional traction vehicles with independent powered electric multiple units (IPEMU) on partially electrified suburban railways. IPEMUs can operate in two modes of power supply – using overhead catenary or onboard battery storage. Appropriate computer simulations were carried out in the Matlab program, indicating the parameters of storage electric multiple units.

  • Strategic Flexibility as a Mediator in Relationship between Managerial Decisions and Organizational Learning: Ambidexterity Perspective
    • Monika Stelmaszczyk
    • Agata Pierścieniak
    2020 Full text European Research Studies Journal

    Purpose: The purpose of the article is to determine strategic flexibility in the relationship between managerial decisions and organizational learning. The analyses are conducted in the ambidexterity convection. Design/Methodology/Approach: The study was conducted at a textile company. The company is a leader in the textile recycling industry in Poland. Empirical data were collected using the PAPI technique. The survey questionnaire was addressed to all 138 company managers. The response rate was 57%. Linear regression analyses were performed to test the research hypotheses. The significance of indirect effects was checked using the bootstrap method. Findings: Our findings show that as the ambidexterity oriented managerial decisions increases, the organizational learning ambidexterity increases. This relationship mediates strategic flexibility through variable flexibility resources and flexibility coordination. In fact, we have indicated the effect of double mediation. This means that there is a relationship between the independent variable and the dependent variable because of interacting resource flexibility and coordination flexibility. Practical Implications: Our study shows that managerial decisions in the company will become more conducive for improving current ideas and introducing new ideas, including ways of their implementation if the enterprise undertakes the proposed steps. They include the acquisition of resources, to develop practical skills, to care in maintaining relatively low costs and shortening task execution duration, to be able to switch to alternative uses of resources. Originality/Value: The value of our research is gaining new knowledge about strategic flexibility. Arguing its necessity for the existence of relationships between managerial decisions and organizational learning, using the ambidexterity convention, improves the knowledge regarding the identity of this category of flexibility.

  • Stratification of nano-pigments in anti-corrosive coatings by means of magnetic field
    • Andrzej Miszczyk
    • Kazimierz Darowicki
    2020 Full text PROGRESS IN ORGANIC COATINGS

    The concept of self-stratification of coatings, although attractive, causes difficulties in its practical use, especially when pigments are added to the resins. An alternative way of obtaining a multilayer structure in a single step was presented. Using the inhomogeneous magnetic field and magnetically active components of the coating, the possibility of vertically graded differentiation of the one layer properties has been verified. For this purpose, the magnetic properties of nickel ferrite (NiFe2O4) nano-particles and magnetic field for their transport in a wet coating were used. It has been shown that it is possible to use the magnetic field to transport magnetic ferrite, used as active anticorrosive pigments, near the coating/substrate interface, in the initially homogeneous wet paint layer, during film formation. These results prove that magnetic ferrite pigments can be magnetically manipulated in liquid coating layer applied on the substrate. Using the impedance spectroscopy technique, it was possible to detect stratification by analyzing complex capacity diagrams. As a result of impedance tests, better anti-corrosive properties of the system hardened in the presence of the magnetic field were demonstrated.

  • Stream Reasoning to Improve Decision-Making in Cognitive Systems
    • Caterine Silva de Oliveira
    • Franco Giustozzi
    • Cecilia Zanni-Merk
    • Cesar Sanin
    • Edward Szczerbicki
    2020 Full text CYBERNETICS AND SYSTEMS

    ABSTRACT Cognitive Vision Systems have gained a lot of interest from industry and academia recently, due to their potential to revolutionize human life as they are designed to work under complex scenes, adapting to a range of unforeseen situations, changing accordingly to new scenarios and exhibiting prospective behavior. The combination of these properties aims to mimic the human capabilities and create more intelligent and efficient environments. Contextual information plays an important role when the objective is to reason such as humans do, as it can make the difference between achieving a weak, generalized set of outputs and a clear, target and confident understanding of a given situation. Nevertheless, dealing with contextual information still remains a challenge in cognitive systems applications due to the complexity of reasoning about it in real time in a flexible but yet efficient way. In this paper, we enrich a cognitive system with contextual information coming from different sensors and propose the use of stream reasoning to integrate/process all these data in real time, and provide a better understanding of the situation in analysis, therefore improving decision-making. The proposed approach has been applied to a Cognitive Vision System for Hazard Control (CVP-HC) which is based on Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA) and has been designed to ensure that workers remain safe and compliant with Health and Safety policy for use of Personal Protective Equipment (PPE).

  • Stress Monitoring System for Individuals with Autism Spectrum Disorders
    • Michał Tomczak
    • Marek Wójcikowski
    • Bogdan Pankiewicz
    • Jacek Łubiński
    • Jakub Majchrowicz
    • Daria Majchrowicz
    • Anna Walasiewicz
    • Tomasz Kiliński
    • Małgorzata Szczerska
    2020 Full text IEEE Access

    In this article, a stress monitoring system tailored for individuals with Autism Spectrum Disorders (ASD) and developed for the educational institution is presented. People with ASD face problems with effective stress management due to their high self-perceived levels of stress, poor ability to cope with it, and dificulties with the accurate detection of the source of stress. Consistently, being able to measure stress appears to be highly vital for this specifc group. The design and construction of the measuring system are introduced. The stress monitoring system including autonomic wearable device (wristband), both the electronics and mechanical part, as well as the software application for data analysis are shown. The wearable device includes sensors for measuring heart rate, skin resistance, temperature and movement. A dedicated software application allows for generating reports to evaluate therapeutic effects. The complex stress monitoring system has been tested in an educational institution. It can provide signifcant support in the stress management of people with ASD and become a meaningful assistance in the therapy of neurodiverse individuals.

  • Stress-driven nonlocal elasticity for nonlinear vibration characteristics of carbon/boron-nitride hetero-nanotube subject to magneto-thermal environment
    • Hamid M. Sedighi
    • Mohammad Malikan
    2020 Full text PHYSICA SCRIPTA

    Stress-driven nonlocal theory of elasticity, in its differential form, is applied to investigate the nonlinear vibrational characteristics of a hetero-nanotube in magneto-thermal environment with the help of finite element method. In order to more precisely deal with the dynamic behavior of size-dependent nanotubes, a two-node beam element with six degrees-of freedom including the nodal values of the deflection, slope and curvature is introduced. In comparison with the conventional beam element, the vector of nodal displacement for the proposed element has one additional component indicating the nodal curvature to comply with the stress-driven nonlocal beam model. The nonlinear term associated with the von Kármán strain is included in the governing equation of motion and it is assumed that the nanotube structure is exposed to temperature changes and surrounded by a magnetic field. The obtained results endorsing the amplitude-dependence of the nonlinear frequencies are justified compared to those reported in the literature and a detailed study is conducted to explore the effect of different parameters on the vibrational behavior of the considered nano-hetero-structure.

  • Striking elements - A lifebelt or a fad? Searching for an effective way of adapting abandoned churches.
    • Agnieszka Szuta
    • Jakub Szczepański
    2020 Full text Frontiers of Architectural Research

    Are avant-garde elements added to historical objects as a temporary fashion to fulfill the aspirations of designers or an attempt to draw attention to themselves? It may be the exact opposite, and this type of controversial project is the best lifebelt for such monuments. This article explores issues related to external avant-garde elements added to adapted churches and their influence on the efficiency of such adaptation projects. Gothic churches located in the north of Europe that have changed their religious function, entirely or in part, were considered. This work examined former churches in Maastricht, namely, the Minorite Church, the Church of the Kruisheren Monastery, the Dominican Church, as well as Polish churches located in Gda nsk, including St. John’s Church and St. Catherine’s Church. This article attempted to identify the factors that contribute to the successful adaptation of former churches and the benefits and drawbacks of adopting avant-garde design solutions. Results of this study might provide valuable inspiration for other churches that are losing worshippers. This study was conducted on the basis of a wide range of literature, statistical data, logical reasoning, and comparative methods. Observations from selected edifices were checked for their correlation over time. This study also included in situ investigations.

  • Structural and catalytic properties of ceria layers doped with transition metals for SOFCs fueled by biogas
    • Bartosz Hołówko
    • Patryk Błaszczak
    • Mikołaj Chlipała
    • Maria Gazda
    • Sea-Fue Wang
    • Piotr Jasiński
    • Beata Bochentyn
    2020 Full text INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    The aim of this paper was to investigate an influence of the nanocrystalline Ce0.8A0.2O2-δ (A = Mn, Fe, Co, Ni, Cu) materials on the direct internal reforming of biogas in SOFC. Structural analysis of fabricated compounds has been done. An in-situ analysis of a composition of outlet gases from operating SOFC was performed using FTIR spectroscopy with simultaneous electrical tests. It was found out, that type of dopant strongly affects biogas reforming process. The differences in absolute values of current density resulted mostly from a microstructure and probably phase composition of a deposited layers. Fuel cells with Ce0.8Co0.2O2-δ and Ce0.8Ni0.2O2-δ additional layers presented the highest drop of current density after switching from hydrogen to biogas, but simultaneously they were the most stable in time. Additional chemical analysis revealed that steam reforming and methane pyrolysis might be dominating reactions while working in biogas atmosphere.

  • Structural and Temporal Topic Models of Feedbacks on Service Quality – A Path to Theory Development?
    • Ojo Adegboyega
    • Nina Rizun
    2020

    There is growing interest in applying computational methods in analysing large amount of data without sacrificing rigour in Information Systems research. In this paper, we demonstrate how the use of structural and temporal topic modelling can be employed to produce insights of both theoretical and practical importance from the analysis of textual comments on the quality of services in hospitals. As a first step, we revealed the thematic structures in the comments as topics which were aligned with the SERVQUAL dimensions. Following this, we established the temporal precedence among SERVQUAL factors based on the evolution of the topics over time. Theoretically, our findings are consistent with the emerging consensus on the nature of SERVQUAL dimensions from extant quantitative research and offer new propositions on the relationships among these dimensions. From the practice perspective, we produced quantified measures of factors associated with healthcare service experience