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Gdańsk University of Technology

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Publications from the year 2021

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  • Evaluation of suspended rail vehicle movement parameters
    • Mateusz Kuczyk
    • Piotr Jędrzejewski
    • Paweł Załuski
    2021 Full text Pojazdy Szynowe

    Niniejsza publikacja została poświęcona ocenie parametrów ruchowych koncepcyjnego pojazdu kolei podwieszanej, którą dokonano w oparciu o jego charakterystykę trakcyjną oraz możliwości dynamiczne. W pierwszej kolejności skrótowo opisano konstrukcję proponowanego pojazdu wraz z wyszczególnieniem najważniejszych założeń projektowych. Następnie skupiono się na metodyce oraz samym wykreśleniu charakterystyki trakcyjnej pojazdu, jak również przebiegu jego przyspieszenia w funkcji prędkości. Na koniec poddano ocenie układ hamulcowy poprzez wyznaczenie średniego opóźnienia hamowania w zależności od jego rodzaju. Artykuł ten powstał na podstawie pracy dyplomowej pt. „Koncepcja wagonu silnikowego kolei podwieszanej”, na wydziale Mechanicznym Politechniki Gdańskiej.

  • Evaluation of Temperature Influence on Electrochemical Processes Occurring in a Lithium-Ion Supercapacitor with the Use of Dynamic Electrochemical Impedance Spectroscopy
    • Michał Mielniczek
    • Ewa Janicka
    • Łukasz Gaweł
    • Kazimierz Darowicki
    2021 Full text ENERGIES

    In order to obtain the full impedance characteristics of a lithium-ion capacitor as a function of temperature, the authors proposed the use of dynamic electrochemical impedance spectroscopy. Impedance tests were carried out under wide range of dynamic temperature changes for lithium-ion supercapacitors. Significant differences in electrochemical processes were observed as a result of working temperature. Moreover, the quality of fitting of the equivalent circuits most frequently used in impedance analysis of lithium-ion capacitors was discussed. The proposed methodology allows for a comprehensive characterization of the performance of these devices and provides key information for their optimization in wide range of operations.

  • Evaluation of the Macro- and Micro-Economic Factors Affecting the Financial Energy of Households
    • Tomasz Korol
    2021 Full text ENERGIES

    This paper is an evaluation of the common macro-economic, micro-economic, and social factors affecting households’ financial situations. Moreover, the author’s objective was to develop a fuzzy logic model for forecasting fluctuations in the number of nonperforming consumer loans in a country using the example of Poland. This study represents one of the first attempts in the global literature to develop such a forecasting model based on macro-economic factors. The findings confirm the usefulness of the proposed innovative approach to forecasting the volume of household insolvencies in a country.

  • Evaluation of the Possibility of Identifying a Complex Polygonal Tram Track Layout Using Multiple Satellite Measurements
    • Andrzej Wilk
    • Cezary Specht
    • Władysław Koc
    • Krzysztof Karwowski
    • Jacek Skibicki
    • Jacek Szmagliński
    • Piotr Chrostowski
    • Paweł Dąbrowski
    • Mariusz Specht
    • Marek Zienkiewicz
    • Sławomir Judek
    • Marcin Skóra
    • Sławomir Grulkowski
    2021

    We present the main assumptions about the algorithmization of the analysis of measurement data recorded in mobile satellite measurements. The research team from the Gda´nsk University of Technology and the Maritime University in Gdynia, as part of a research project conducted in cooperation with PKP PLK (Polish Railway Infrastructure Manager), developed algorithms supporting the identification and assessment of track axis layout. This article presents selected issues concerning the identification of a tramway line’s axis system. For this purpose, the supporting algorithm was developed and measurement data recorded using Global Navigation Satellite System (GNSS) techniques was evaluated and analyzed. The discussed algorithm identifies main track directions from multi-device data and repeated position recordings. In order to observe the influence of crucial factors, the investigated route was carefully selected. The chosen tramway track was characterized by its location in various field conditions and a diversified and complex geometric layout. The analysis of the obtained results was focused on the assessment of the signal’s dispersion and repeatability using residuals in relation to the estimated track’s direction. The presented methodology is intended to support railway infrastructure management processes, mainly in planning and maintenance through an efficient inventory of the infrastructure in service.

  • Evaluation of the potential of Microwave Plasma–Atomic Emission Spectrometry for trace elements leaching assessment from the concrete matrix with sewage sludge ash additives
    • Alicja Saczuk
    • Paulina Augustyniak
    • Elżbieta Haustein
    • Bartłomiej Cieślik
    2021

    The management of ash generated during the thermal utilization of sewage sludge is a significant environmental problem requiring an effective technological solution. One alternative way to dispose of sewage sludge is to bind it in concrete as a substitute for part of the aggregate. The properties of the C-S-H phase enable effective immobilization of harmful substances that sewage sludge contains. The amount of individual compounds and elements is variable and fully dependent on the characteristics of the wastewater flowing into the sewage sludge treatment plant. The research investigated the effect of the addition of sewage sludge as a replacement for part of the sand, on the fresh concrete mix and the characteristics of the hardened concrete. The behavior of heavy metals were subjected to observation using microwave plasma–atomic emission spectrometer in three environments, such as nitric acid (pH ≈ 3), artificial ground-water and seawater solutions. The validity of using advanced spectroscopic methods, such as mentioned microwave plasma–ato-mic emission spectrometer, for improving the assessment of the danger of using waste materials in modern building materials was considered.

  • Eventual Convergence of the Reputation-Based Algorithm in IoT Sensor Networks
    • Jacek Lebiedź
    • Piotr Cofta
    • Cezary Orłowski
    2021 Full text SENSORS

    Uncertainty in dense heterogeneous IoT sensor networks can be decreased by applying reputation-inspired algorithms, such as the EWMA (Exponentially Weighted Moving Average) algorithm, which is widely used in social networks. Despite its popularity, the eventual convergence of this algorithm for the purpose of IoT networks has not been widely studied, and results of simulations are often taken in lieu of the more rigorous proof. Therefore the question remains, whether under stable conditions, in realistic situations found in IoT networks, this algorithm indeed converges. This paper demonstrates proof of the eventual convergence of the EWMA algorithm. The proof consists of two steps: it models the sensor network as the UOG (Uniform Opinion Graph) that enables the analytical approach to the problem, and then offers the mathematical proof of eventual convergence, using formalizations identified in the previous step. The paper demonstrates that the EWMA algorithm converges under all realistic conditions.

  • Evolution of Edges and Porosity of Urban Blue Spaces: A Case Study of Gdańsk
    • Justyna Breś
    • Karolina Krośnicka
    2021 Full text Urban Planning

    Current waterfront studies focus mainly on a land-based perspective, failing to include the water side. Water is, however, not just a resource for port and industrial purposes and an edge to the waterfront; it is also a feature of the waterfront and the complex relation between water and city. Thus, the article suggests that water-land edges need to be re-contextualised, taking into consideration also their shape, functionality, and evolution over time. This article therefore introduces the concept of urban blue spaces, that is, spaces that include at least one land-water edge, such as a shoreline or river edge. The types and character of these edges define the porosity of urban blue spaces: Spaces with easy connections, such as boulevards or parks, are highly porous, while fenced areas have low porosity. The research first analyses the existing literature on the spatial and functional characteristics of the land-water edge in port cities, and explores existing typologies of urban blue spaces. The results of this investigation are used to examine the most iconic urban blue space of Gdańsk, the Motława river, over the last 1000 years. The case study shows that the porosity of the Gdańsk urban blue space has been increasing over time, in line with its spatial and functional development from an undeveloped riverbank to a ‘gated’ port and industry area, to urban living spaces today. The article thus presents the whole breadth of urban blue spaces through the case study of the Motława river urban blue space. The spatial evolution of the urban blue space is depicted through the transformation of its land-water edge—from a natural sloping edge to the dominance of vertical edged structures or ones overhanging the surface of the water, to the emergence of spatially ‘blurred’ sloping, slanted, terraced, and floating structures, partially independent of the riverbank. The transformation of the structure of the Motława urban blue space edges increased its complexity over time, from a single-edge structure to a double and multiple-edged one.

  • Evolutionary benefits of personality traits when facing workplace bullying
    • Anna Maria Dåderman
    • Beata Basińska
    2021 Full text PERSONALITY AND INDIVIDUAL DIFFERENCES

    Facing workplace bullying negatively affects physical and mental health, and consequently quality of life and well-being. Personality traits that can help an individual survive and reproduce entail more benefits than costs. Building on two evolutionary theories, Life History Theory and Costly Signaling Theory, this study aims to provide novel insights into how and why personality traits are associated with facing workplace bullying and health-related quality of life. A heterogeneous group of 324 employees in Sweden provided data on workplace bullying, perceived health-related quality of life, and personality traits, controlling for sex and age. We found that openness (HEXACO model) and Machiavellianism (Dark Triad model) served as moderators. Employees with high values of these traits experienced significantly less affected health-related quality of life when facing workplace bullying. Our results indicate evolutionary origins of the personality traits openness and Machiavellianism. A new finding is that possessing, exhibiting, and maintaining traits reflecting a more creative and competitive interpersonal style increases an employee’s ability to survive aversive environments.

  • Examination of selected failure criteria with asymmetric shear stresses in the collapse analysis of laminated shells
    • Jacek Chróścielewski
    • Agnieszka Sabik
    • Bartosz Sobczyk
    • Wojciech Witkowski
    2021 COMPOSITE STRUCTURES

    The paper is concerned with failure analysis of composite shells performed with the usage of the nonlinear 6‐parameter shell theory with drilling rotation degree of freedom. This special theory embodies naturally unlim-ited translations and rotations and is suitable for analysis of irregular shells for instance with various, partic-ularly orthogonal, intersections. The presence of the drilling rotation is inherently accompanied withasymmetry of in‐plane shear stresses and strains which must be taken into account in the composite failure cri-teria. In the paper in general two failure measures are applied: Hashin criterion and Tsai‐Wu criterion whichare appropriately modified to accommodate the stress asymmetry. It is shown, that depending on the used fail-ure criterion, it is possible to obtain slightly different damage zones and values of thefirst ply failure and ulti-mate load. These values are compared with those obtained experimentally.

  • Examination of Spectral Properties of Medicinal Plant Leaves Grown in Different Lighting Conditions Based on Mint Cultivation
    • Mateusz Feldzensztajn
    • Paweł Wierzba
    • Adam Mazikowski
    2021 Full text SENSORS

    Cultivation in controlled environmental conditions can provide good quality medicinal herbs with consistent properties. A sensing system that can determine the contents of medicinal substances in plants using spectral characteristics of leaves would be a valuable tool. Viability of such sensing approach for mint had to be confirmed experimentally, as no data correlating contents of medicinal substances with spectral characteristics of leaves are available, to the best of authors’ knowledge. In the first stage, presented in this paper, the influence of lighting on mint (Mentha rotundifolia) grown on a small hydroponic plantation was studied. Spectral characteristics of leaves were recorded by a spectrophotometer and colorimetric analysis was used to investigate the relationship between these characteristics and the spectrum of lighting. Dry mass yield was measured to test its dependence on the lighting. Dependence of chromaticity of leaves on the spectrum of light used in the cultivation was confirmed. Averaged spectra of leaves are distinguishable using a spectrophotometer and—in most cases—by a human observer. A partial correlation is observed between dry mass yield and the spectrum of lighting. Obtained results justify further research into the correlation between lighting and the contents of biological substances in medicinal plants using spectral characteristics of leaves.

  • Examining Statistical Methods in Forecasting Financial Energy of Households in Poland and Taiwan
    • Tomasz Korol
    2021 Full text ENERGIES

    This paper examines the usefulness of statistical methods in forecasting the financial energy of households. The study’s objective is to create the innovative ratios that combine both financial and demographic information of households and implement them in the forecasting models. To conduct this objective, six forecasting models are developed using three different methods—discriminant analysis, logit analysis, and decision trees separately for households in Poland and Taiwan. Such a research approach will answer the question whether the implementation of constructed ratios can increase effectiveness of the forecasting model and its’ versatility between different economic regions. The research relies on four samples of households—two learning samples and two testing samples (one for each country) consisting of 2400 households from both countries. This study is one of the first attempts in the literature globally to develop forecasting models based on ratios constructed with a combination of two different types of variables—one financial with one demographic variable. Findings confirm the high usability of the proposed innovative approach for forecasting the financial energy of households by taking into account a wide spectrum of diagnostic variables representing the financial strength of consumers.

  • Exergy and Energy Analyses of Microwave Dryer for Cantaloupe Slice and Prediction of Thermodynamic Parameters Using ANN and ANFIS Algorithms
    • Safoura Zadhossein
    • Yousef Abbaspour-Gilandeh
    • Mohammad Kaveh
    • Mariusz Szymanek
    • Esmail Khalife
    • Olusegun D. Samuel
    • Milad Amiri
    • Jacek Dziwulski
    2021 Full text ENERGIES

    The study targeted towards drying of cantaloupe slices with various thicknesses in a microwave dryer. The experiments were carried out at three microwave powers of 180, 360, and 540 W and three thicknesses of 2, 4, and 6 mm for cantaloupe drying, and the weight variations were determined. Artificial neural networks (ANN) and adaptive neuro-fuzzy inference systems (ANFIS) were exploited to investigate energy and exergy indices of cantaloupe drying using various afore-mentioned input parameters. The results indicated that a rise in microwave power and a decline in sample thickness can significantly decrease the specific energy consumption (SEC), energy loss, exergy loss, and improvement potential (probability level of 5%). The mean SEC, energy efficiency, energy loss, thermal efficiency, dryer efficiency, exergy efficiency, exergy loss, improvement potential, and sustainability index ranged in 10.48–25.92 MJ/kg water, 16.11–47.24%, 2.65–11.24 MJ/kg water, 7.02–36.46%, 12.36–42.70%, 11.25–38.89%, 3–12.2 MJ/kg water, 1.88–10.83 MJ/kg water, and 1.12–1.63, respectively. Based on the results, the use of higher microwave powers for drying thinner samples can improve the thermodynamic performance of the process. The ANFIS model offers a more accurate forecast of energy and exergy indices of cantaloupe drying compare to ANN model.

  • Existence of Two Periodic Solutions to General Anisotropic Euler-Lagrange Equations
    • Magdalena Chmara
    2021 Full text TAIWANESE JOURNAL OF MATHEMATICS

    Abstract. This paper is concerned with the following Euler-Lagrange system d/dtLv(t,u(t), ̇u(t)) =Lx(t,u(t), ̇u(t)) for a.e.t∈[−T,T], u(−T) =u(T), Lv(−T,u(−T), ̇u(−T)) =Lv(T,u(T), ̇u(T)), where Lagrangian is given by L=F(t,x,v) +V(t,x) +〈f(t),x〉, growth conditions aredetermined by an anisotropic G-function and some geometric conditions at infinity.We consider two cases: with and without forcing termf. Using a general version ofthe mountain pass theorem and Ekeland’s variational principle we prove the existenceof at least two nontrivial periodic solutions in an anisotropic Orlicz-Sobolev space.

  • Expedited Acquisition of Database Designs for Reduced-Cost Performance-Driven Modeling and Rapid Dimension Scaling of Antenna Structures
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2021 Full text IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    Fast replacement models have been playing an increasing role in high-frequency electronics, including the design of antenna structures. Their role is to improve computational efficiency of the procedures that normally entail large numbers of expensive full-wave electromagnetic (EM) simulations, e.g., parametric optimization or uncertainty quantification. Recently introduced performance-driven modeling methods, such as the nested kriging framework, alleviate some of the common difficulties pertinent to conventional modeling methods. These include the curse of dimensionality but also the need for rendering models to be valid for broad ranges of antenna parameters and operating conditions, as dictated by the design utility of the surrogates. The keystone of performance-driven methods is an appropriate confinement of the model domain so that the training data is only acquired in the regions containing high-quality designs. Identification of such regions is realized using a set of so-called reference designs pre-optimized for selected ensembles of performance requirements. The CPU cost of generating the reference points may be considerable and compromise the savings obtained by operating in a constrained domain. In this paper, a technique for automated, reliable and low-cost acquisition of the reference designs is proposed. Our methodology involves inverse sensitivities, iterative correction procedures, and accelerated feature-based gradient search with sparse Jacobian updates. It is validated using three microstrip antenna examples and demonstrated as an efficient tool for lowering the cost of building surrogate models within the nested kriging framework. The intended use of our approach is expedited construction of database designs for constrained modeling frameworks, construction of inverse surrogates as well as procedures for rapid re-design and dimension scaling of antenna structures.

  • Expedited Trust-Region-Based Design Closure of Antennas by Variable-Resolution EM Simulations
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Leifur Leifsson
    2021

    The observed growth in the complexity of modern antenna topologies fostered a widespread employment of numerical optimization methods as the primary tools for final adjustment of the system parameters. This is mainly caused by insufficiency of traditional design closure approaches, largely based on parameter sweeping. Reliable evaluation of complex antenna structures requires full-wave electromagnetic (EM) analysis. Yet, EM-driven parametric optimization is, more often than not, extremely costly, especially when global search is involved, e.g., performed with population-based metaheuristic algorithms. Over the years, numerous methods of lowering these expenditures have been proposed. Among these, the methods exploiting variable-fidelity simulations started gaining certain popularity. Still, such frameworks are predominantly restricted to two levels of fidelity, referred to as coarse and fine models. This paper introduces a reduced-cost trust-region gradient-based algorithm involving variable-resolution simulations, in which the fidelity of EM analysis is selected from a continuous spectrum of admissible levels. The algorithm is launched with the coarsest discretization level of the antenna under design. As the optimization process converges, for reliability reasons, the model fidelity is increased to reach the highest level at the final stage. The proposed algorithm allows for a significant reduction of the computational cost (up to sixty percent with respect to the reference trust-region algorithm) without compromising the design quality, which is corroborated by thorough numerical experiments involving four broadband antenna structures.

  • Experience marketing in the service of the “secular religion” of big tech
    • Jan Kreft
    • Monika Boguszewicz-kreft
    2021 Full text

    The article proposes an interpretation of the meaning of experience marketing as a tool in the process of sacralisation of products, and in a broader context – the so-called secular religion accompanying some contemporary big tech organizations. The article is of theoretical nature and the authors have intended to explain how big tech corporations, in line with the concept of experience marketing (digital platforms, in particular), reinterpret their role in relations with users. The aim of the article is to inspire research on the experience marketing in the digital ecosystem in the context of the sacralisation of an organization, its goals, leaders, employees and products. The article has adopted hermeneutics as providing an appropriate theoretical framework for analysis.

  • Experience-Based Product Inspection Planning for Industry 4.0
    • Muhammad Ahmed
    • Farhat Majeed
    • Cesar Sanin
    • Edward Szczerbicki
    2021 Full text CYBERNETICS AND SYSTEMS

    In this paper we describe how our Smart Virtual Product Development (SVPD) system can be used to enhance product inspection planning. The SVPD system is comprised of three main modules, these being the design knowledge management (DKM) module, the manufacturing capability and process planning (MCAPP) module, and the product inspection planning (PIP) module. Experiential knowledge relating to formal decisional events is collected, stored and used by the system in the form of set of experiences (SOEs). Here we discuss the working mechanism of the PIP module and show how experiential knowledge relating to the inspection of products that have features and functions in common can be used to enhance product inspection planning during early stages of product development. Our discussion commences with an introduction to fundamental concepts and a general system overview. We then describe the development of our SVPD system’s PIP module, and a case study we undertook for validation purposes. Results of the case study show that our system is capable of supporting product inspection planning in smart manufacturing, and thus has a vital role to play in Industry 4.0.

  • Experimental analysis of the behaviour of different types of joints in the steel structure model subjected to earthquake loading
    • Tomasz Jaroszewski
    • Tomasz Falborski
    • Robert Jankowski
    2021 Full text Journal of Physics : Conference Series

    The present paper reports the results of the experimental study performed to investigate the behaviour of two different types of joints (destroyed and welded ones) in the model of the steel structure under seismic excitations. The structure was subjected to three earthquakes, namely Kobe, Loma Prieta and Northridge, using the shaking table investigation. The results obtained from the study indicate that there is a significant difference between the behaviour of destroyed joints and welded ones. It was concluded that the destroyed joints experience higher acceleration than the welded joints during different earthquakes.

  • Experimental and Computational Fluid Dynamics Studies on Straight and U-Bend Double Tube Heat Exchangers with Active and Passive Enhancement Methods
    • Rafał Andrzejczyk
    • Tomasz Muszyński
    • Przemysław Kozak
    2021 HEAT TRANSFER ENGINEERING

    In this work, the authors wanted to demonstrate the possibility to increase the heat transfer efficiency by using simple wire coil inserts to create turbulent flow in the boundary layer as well as air blowing into the annulus of the pipe. Experimental investigations were carried out for four heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend double tube, U-tube with turbulator, plain double tube and U-bend double tube working with two-phase flow conditions (air-water mixture). For these geometries, the values of pressure drop and heat flux were determined. The comparison of heat transfer efficiency was performed based on NTU-e method. The computational fluid dynamics (CFD) technique was also employed to investigate the influence of coiled wire inserts and air bubbly injection at heat transfer, pressure drops and overall efficiency in double tube heatexchangers. For this purpose, six configurations of heat exchangers were meshed and simulated at various flow conditions by using the CFD package Autodesk CFD 2016 (Students & Educators version).

  • Experimental and Numerical Investigation of Tensile and Flexural Behavior of Nanoclay Wood-Plastic Composite
    • M. E. Golmakani
    • Tomasz Wiczenbach
    • Mohammad Malikan
    • Seyed M. Mahoori
    • Victor Eremeev
    2021 Full text Materials

    In this study, the effect of wood powder and nanoclay particle content on composites’ mechanical behavior made with polyethylene matrix has been investigated. The wood flour as a reinforcer made of wood powder was at levels of 30, 40, and 50 wt.%, and additional reinforcement with nanoclay at 0, 1, 3, and 5 wt.%. Furthermore, to make a composite matrix, high-density polyethylene was used at levels of 70, 60, and 50% by weight. Wood-plastic composite (WPC) specimens were manufactured in injection molding. After preparing the specimens, tensile and bending tests were performed on samples. The mechanical properties such as tensile and flexural strength and flexural modulus were measured. Results showed that nanoclay particle content increases flexural modulus, flexural strength, modulus of elasticity, and tensile strength. The experimental test results show that Young’s moduli increased with the volume of wood flour. The biggest modulus of elasticity was achieved in the samples having 50 wt.% of wood powder. Furthermore, the highest value of tensile strength was achieved at the level of 30 wt.%. The highest flexural strength was for the sample containing 50% wood powder by weight. Additionally, a numerical model was made utilizing the Abaqus software using the finite element method (FEM). Comparing the numerical and experimental results, it was found that they are compatible in the linear-elastic and plastic state of the material. There are no crucial differences between experiment and FEM.