Publications Repository - Gdańsk University of Technology

Page settings

polski
Publications Repository
Gdańsk University of Technology

Show publications from the year

Publications from the year 2023

Show all
  • Experimental study and numerical simulation of the dynamic penetration into dry clay
    • Victor Eremeev
    • V Balandin
    • Vl Balandin
    • Anatoly Bragov
    • Alexander Konstantinov
    • Leonid Igumnov
    2023 Full text CONTINUUM MECHANICS AND THERMODYNAMICS

    Tests of dry clay were carried out in a uniaxial stress state using the experimental setup which implements the split Hopkinson pressure bar method. Based on the results of these experiments, the compressive strength of clay was determined as an important element of S.S. Grigoryan’s model of the soil medium. In addition, the parameters of this model are determined from the results of experiments using the modified Kolsky method with a sample enclosed in a rigid cage. To verify the model of the soil medium, special experiments were carried out on the penetration of striker with conical tips into dry clay in a reversed settings. Using this identified model in the LS-Dyna software package, numerical simulation of penetration into clay was carried out under conditions similar to those carried out the reversed experiments. Comparison of the results of physical and numerical experiments showed their satisfactory agreement at a dry friction coefficient of 0.5.

  • Experimental study of flow boiling pressure drop and heat transfer of R1233zd(E) at moderate and high saturation temperatures
    • Michał Pysz
    • Stanisław Głuch
    • Dariusz Mikielewicz
    2023 Full text INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

    The paper presents the results of experimental study of flow boiling of R1233zd(E) in minichannel at moderate and high saturation temperatures. The heat transfer coefficient and pressure drop were measured for flow boiling in a stainless steel tube with 2 mm inside diameter and a length of 300 mm. Experiment has been conducted for saturation temperatures ranging from 83 to 145 °C which corresponds to values of reduced pressures ranging from 0.2 to 0.7. Three different heat fluxes were analyzed, namely 20, 30 and 45 kW/m2 and mass velocities ranged from 200 to 1000 kg/m2s. The effects of reduced pressure, mass velocity, heat flux, vapor quality and flow regime were analyzed. At low reduced pressures (pr≤ 0.3) heat transfer is driven by convective boiling mostly with nucleate boiling having effect only in the case of low mass velocities. Heat transfer in this case increases with mass velocity and vapor quality and is independent of heat flux. For reduced pressures of 0.4 and 0.5 both nucleate and convective boiling are present, however the nucleate boiling starts to be more dominant here, especially for low mass velocities and high heat fluxes. For low mass velocities and/or higher heat fluxes the heat transfer decrease or is independent of vapor quality, whereas for higher mass fluxes and/or lower heat fluxes it is initially independent of vapor quality and starts to increase close to the transition from intermittent to annular flow. At the range of high reduced pressures (pr ≥ 0.6) nucleate boiling is the dominant heat transfer mechanism. Experimental results were compared with some well-known two-phase flow correlations.

  • Experimental Study of Flow Rate in Hydraulic Satellite Motor with the Rotating Case at a Low Constant Rotational Speed
    • Paweł Śliwiński
    • Piotr Patrosz
    • Marcin Bąk
    • Michał Stosiak
    • Kamil Urbanowicz
    • Šarūnas Šukevičius
    2023

    In this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of the curvature, satellites and in the commutation unit gaps were determined. The test results also allowed to evaluate the correct operation of the commutation unit and the compensation unit of axial clearances of the curvature and satellites in the working mechanism of the motor.

  • Experimental Study of Polish Sausage Drying Kinetics and Contraction by Image Data Analysis
    • Blanka Jakubowska
    2023 Full text Acta Universitatis Cibiniensis - Series E: Food Technology

    The goal of this paper has been to add an experimental data set for drying a meat product and provide a comparison with well-established thin-layer drying models. This article presented experimental investigations on the convective drying of Polish sausage slices at a temperature of 40°C. Slices have been in the thickness of 3 to 8mm. Measurements of mass loss and size change were performed. The data have been presented in the form of standard drying kinetics. Additionally, the estimation of the diffusion coefficient according to the simplified graphical approach is made. Based on the best-fit approach the coefficients for typical semiempirical correlations for MR (moisture ratio) estimation have been calculated and presented.

  • Experimental study on earthquake-induced pounding between steel structures
    • Barbara Sołtysik
    • Robert Jankowski
    2023 ce/papers

    Pounding between adjacent structures has been repeatedly observed during major earthquakes. The phenomenon may cause some local damage at the points of interactions, it may also lead to substantial destruction, permanent deformations or total collapse of colliding structures. The effects of earthquake-induced structural pounding have been studied for more than three decades now. However, most of the studies concerned masonry as well as reinforced concrete structures and investigations on steel structures are very limited. The aim of the present paper is to show the results of the shaking table experimental investigation focused on earthquake-induced pounding between three models of steel structures in a row. The models were constructed out of four steel columns made from rectangular box section with additional steel skew bracings so as to prevent transverse and torsional vibrations. To obtain different dynamic characteristics of the models, additional plates were added at the top of each tower. Two configurations were investigated. In the first one, two plates were mounted on the external structures and only one plate at the top of the middle tower. In the second configuration, only one plate was mounted at the top of external towers and two plates on the middle structure. Firstly, the free vibration tests were conducted. Then, the steel towers with different in-between gap sizes were tested under different earthquakes. The results of the study confirm that interactions between insufficiently separated steel structures may significantly influence the structural behaviour during earthquakes. In most of the cases, pounding has resulted in the increase in the peak responses. In some cases, however, it has played a positive role leading to the decrease in the structural response under seismic excitation. Anyway, even if the response is reduced, interactions should be prevented at the design stage of steel structures since they may result in considerable damage at the points of impacts.

  • Experimental study on the effect of selected sterilization methods on mechanical properties of polylactide FFF specimens
    • Angela Andrzejewska
    2023 Full text RAPID PROTOTYPING JOURNAL

    Purpose: Biodegradable polymers are widely used in personalized medical devices or scaffolds for tissue engineering. The manufacturing process should be finished with sterilization procedure. However, it is not clear how the different sterilization methods have an impact on the mechanical strength of the three-dimensional (3D)-printed parts, such as bone models or personalized mechanical devices. This paper aims to present the results of mechanical testing of polylactide-based bone models before and after sterilization. Design/methodology/approach: Polylactide specimens prepared in fused filament fabrication technology were sterilized with different sterilization methods: ultraviolet (UV) and ethylene oxide. Mechanical properties were determined by testing tensile strength, Young’s modulus and toughness. Findings: The tensile strength of material after sterilization was significantly higher after ethylene oxide sterilization compared to the UV sterilization, but in both sterilization methods, the specimens characterized lower tensile strength and Young’s modulus when compared to the control. In comparison of toughness results, there was no statistically significant differences. The findings are particularly significant in the perspective of using individual implants, bone grafts and dental guides. Originality/value: Although fused filament fabrication (FFF) 3D printing devices equipped with UV light sterilization options are available, experimental results of the effect of selected sterilization methods on the mechanical strength of additively manufactured parts have not been described. This paper completes the present state of the art on the problem of sterilization of FFF parts from biodegradable materials.

  • Experimental ultimate strength assessment of stiffened plates subjected to marine immersed corrosion
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    • Jakub Kowalski
    2023 Full text APPLIED OCEAN RESEARCH

    This study experimentally analyses the impact of marine immersed corrosion degradation on the compressive strength of the stiffened plates where the lower degradation levels were considered. The corrosion degradation test was accelerated by controlling the natural corrosion environmental factors, avoiding applying an electric current. Different groups of corrosion degradation levels and initial plate thicknesses were investigated. The specimens were subjected to a compressive load via a universal testing machine. The estimated force-displacement relationships and lateral displacements as a function of the degree of degradation were analysed. Several analyses and discussions showed that considering only the mean value of the corrosion thickness loss, it is insufficient to evaluate the stiffened plates' ultimate strength correctly, and the type of corrosion degradation needs to be accounted for appropriately.

  • Experimental Verification of the CFD Model of the Squeeze Film Lifting Effect
    • Bartosz Bastian
    • Rafał Gawarkiewicz
    • Michał Wasilczuk
    • Michał Wodtke
    2023 Full text Applied Sciences-Basel

    Abstract: The presented study shows the results of the research into the squeeze film levitation phenomena. The system introduced in the investigation is composed of a vibrating surface, air squeeze film, and the surface of the body freely suspended over the film. The use of the CFD (Computational Fluid Dynamics) model used in the system allows us to determine the steady state, periodic behavior of the air film (described by Navier–Stokes, continuity equations, and ideal gas law), and the lifted object dynamics. The model allows us to determine multiple factors, among others, mean film thickness and pressure distribution inside the fluid film. The influence of factors, such as vibration amplitude, frequency, and load on the lifting conditions, was presented. A series of calculations show the levitations height in the range of 5.61 up to 58.12 microns, obtained for masses of samples between 5–20 g, vibration frequency of 5–25 kHz, and the motions amplitude of 0.5–1.5 m. A series of CFD multivariable calculations for a standing wave inducer were not previously published. The CFD model was validated with the use of experiments on a specially developed test rig. The authors experimentally obtained the height of levitation up to 200 microns.

  • Explainable machine learning for diffraction patterns
    • Shahid Nawaz
    • Vahid Rahmani
    • David Pennicard
    • Shabarish Pala Ramakantha Setty
    • Barbara Klaudel
    • Heinz Graafsma
    2023 Full text Journal of Applied Crystallography

    Serial crystallography experiments at X-ray free-electron laser facilities produce massive amounts of data but only a fraction of these data are useful for downstream analysis. Thus, it is essential to differentiate between acceptable and unacceptable data, generally known as ‘hit’ and ‘miss’, respectively. Image classification methods from artificial intelligence, or more specifically convolutional neural networks (CNNs), classify the data into hit and miss categories in order to achieve data reduction. The quantitative performance established in previous work indicates that CNNs successfully classify serial crystallography data into desired categories [Ke, Brewster, Yu, Ushizima, Yang & Sauter (2018). J. Synchrotron Rad. 25, 655–670], but no qualitative evidence on the internal workings of these networks has been provided. For example, there are no visualization methods that highlight the features contributing to a specific prediction while classifying data in serial crystallography experiments. Therefore, existing deep learning methods, including CNNs classifying serial crystallography data, are like a ‘black box’. To this end, presented here is a qualitative study to unpack the internal workings of CNNs with the aim of visualizing information in the fundamental blocks of a standard network with serial crystallography data. The region(s) or part(s) of an image that mostly contribute to a hit or miss prediction are visualized.

  • Exploring Stock Traders’ Cognitive Biases: Research Design and Simulator Framework
    • Maciej Tkacz
    • Józef Żurada
    • Paweł Weichbroth
    2023

    Cognitive bias is a phenomenon that has been extensively studied in stock trading and many other fields. This paper presents a framework for a Mobile Stock Trading Simulator (MSTS) that facilitates automatic investment in stocks with minimal human influence, by investigating the behavioral patterns and cognitive errors of stock market investors. The paper aims to determine whether investors’ investment strategies can be improved by detecting investment threats and reducing investment errors based on investors’ transaction histories. To accomplish this, we built a stock exchange simulator and implemented a decision tree to classify cognitive biases into one of six categories. By incorporating the behavioral patterns and cognitive biases of stock market investors into the MSTS's architecture, and by implementing a decision tree and stock exchange simulator, we can minimize the impact of human influence on automatic investments.

  • Exploring synergistic effects in physical-chemical activation of Acorus calamus for water treatment solutions
    • Beata Barczak
    • Justyna Łuczak
    • Paweł Kazimierski
    • Ewa Klugmann-Radziemska
    • Gartzen Lopez
    • Katarzyna Januszewicz
    2023 JOURNAL OF ENVIRONMENTAL MANAGEMENT

    The research proposed a novel method of obtaining sorption material from readily available Acorus calamus bio- mass through a combination of physical and chemical activation processes. The material with the highest specific surface area (1652 m2 g−1) was obtained by physical activation with CO2, followed by chemical activation with KOH. Reversing the order of activation methods resulted in a lower specific surface area (1014 m2 g−1) of the car- bon sample. Chemical activation produced activated carbon with a surface area of 1066 m2 g−1-, while physical activation produced 390 m2 g−1. This confirms the synergistic effect of combining the two activation methods for biocarbon. It was observed that physical activation with CO2 generates a diverse range of pores, including meso- and macropores, while chemical activation induces the formation of micropores. In contrast, reversing the order of these processes leads to the degradation of the porous structure. The application of physical-chemical activa- tion with synergistic effects represents a significant advancement in producing high-quality activated biocarbon for various applications, such as wastewater treatment and energy storage. The combination of the two activa- tion methods resulted in a synergistic effect, leading to the production of carbon material of higher quality. Addi- tionally, the diversified pore sizes will enable the sorption of various pollutants in the aquatic environment and air pollutants, where gas particles are much smaller.

  • Exploring the influence of personal factors on physiological responses to mental imagery in sport
    • Dagmara Budnik-Przybylska
    • Paweł Syty
    • Maria Kaźmierczak
    • Marta Łabuda
    • Łukasz Doliński
    • Adrian Kastrau
    • Patryk Jasik
    • Jacek Przybylski
    • Selenia di Fronso
    • Maurizio Bertollo
    2023 Full text Scientific Reports

    Imagery is a well-known technique in mental training which improves performance efficiency and influences physiological arousal. One of the biomarkers indicating the amount of physiological arousal is skin conductance level (SCL). The aim of our study is to understand how individual differences in personality (e.g. neuroticism), general imagery and situational sport anxiety are linked to arousal measuring with SCL in situational imagery. Thirty participants aged between 14 and 42 years (M = 22.93; SD = 5.24), with sport experience ranging between 2 and 20 years (M = 10.15; SD = 4.75), took part in our study. Participants listened to each previously recorded script and then were asked to imagine the scene for a minute. During the task SCL was monitored using the Biofeedback Expert 2000. Machine learning predictive models based on artificial neural networks have been trained for prediction of physiological response, as a function of selected psychological tests. We found an association among neuroticism, prestart anxiety, and general tendency to use imagery with SCL. From a practical point of view our results may help athletes, coaches, and psychologists to be more aware of the role of individual differences in sport.

  • Exploring the interfacial effects at the ETL/perovskite boundary in the semitransparent perovskite solar cells
    • Jędrzej Szmytkowski
    • Yulia Galagan
    • Damian Głowienka
    2023 Full text SOLAR ENERGY

    The recent focus has been made on the perovskite solar cells (PSCs) with an inverted configuration, where substantial improvements have been already achieved. However, the p–i–n structure needs a buffer layer for most of the configurations to modify the work-function of a deposited electrode. Additionally and very importantly, such a layer can also serve as a protective film that improves a stability of solar cells. Here, we study the semitransparent inverted PSCs, which have been prepared with the SnO2 buffer layer deposited by a spin-coating method. The main goal was to understand the dominant loss mechanisms in the operation of PSCs. Four photovoltaic parameters (an open-circuit voltage, a short-circuit current, a fill factor and a power conversion efficiency) were measured for a wide range of the light intensity. Their analysis allowed us to identify the transportation and recombination effects using an electrical modeling based on the drift–diffusion model. In addition, it has been concluded that the solution processed PCBM layer might not fully cover the perovskite film. As a consequence, the band-bending effect can occur at the PCBM/perovskite interface, where PCBM plays a role of the Electron Transport Layer (ETL). Therefore, we theoretically investigated the influence of this interface phenomenon on four photovoltaic parameters and the ideality factor simulated as a function of the ETL interface defect density. The increasing of the ideality factor to a high value (above 4) observed for the band-bending level around 300 eV indicates inhomogeneity of the interface. The results of this study should help to better understand the dominant electrical losses in the semitransparent inverted PSCs with a buffer layer which should further help to improve the performance of such devices.

  • Exploring the landscape of automatic cerebral microbleed detection: A comprehensive review of algorithms, current trends, and future challenges
    • Maria Ferlin
    • Zuzanna Klawikowska
    • Michał Grochowski
    • Małgorzata Grzywińska
    • Edyta Szurowska
    2023 Full text EXPERT SYSTEMS WITH APPLICATIONS

    This paper provides the first review to date which gathers, describes, and assesses, to the best of our knowledge, all available publications on automating cerebral microbleed (CMB) detection. It provides insights into the current state of the art and highlights the challenges and opportunities in this topic. By incorporating the best practices identified in this review, we established guidelines for the development of CMB detection systems. We are confident that these guidelines can serve as a foundation for further research. CMB detection is a crucial but challenging task that can be laborious for radiologists. With the increasing popularity of magnetic resonance imaging (MRI), the ability to detect CMBs has improved, but there is still a need to automate this process to enhance its efficiency and accuracy. A high prevalence of CMBs is closely associated with cognitive dysfunction, diabetes, hypertension, an increased risk of stroke, and intracerebral hemorrhage. It is alarming to note that strokes, Alzheimer’s disease, and Diabetes mellitus have secured their position as the second, seventh, and ninth most common causes of death worldwide, respectively. Moreover, CMBs are sometimes found in association with other pathologies and indicate a range of pathological processes in the cerebral vessels. Thus, it is essential to enhance the quality of diagnostics to facilitate prompt identification and treatment of these potentially life-threatening conditions. In this paper, we aimed to systematize the existing knowledge and best practices in automatic CMB detection, from fundamental information about CMBs and MRI image data, through employed datasets and CMB detection and verification algorithms, to methods of result evaluation. This can serve as a starting point for future research and the development of a CMB detection system that is practically applicable in medicine, leading to enhanced patient treatment outcomes.

  • Exploring the Prevalence of Anti-patterns in the Application of Scrum in Software Development Organizations
    • Michał Wróbel
    • Dorota Przała
    • Paweł Weichbroth
    2023 Full text

    The paper presents a survey-based study that aimed to determine the prevalence of anti-patterns in the Scrum software development methodology. A total of 35 anti-patterns were selected from the literature review, and 42 respondents indicated whether they had encountered each anti-pattern in their organizations. The study found that``Unfinished Tasks'' was the most prevalent anti-pattern, highlighting the importance of proper planning and task management within sprints. Additionally, several other common anti-patterns were identified, including daily scrums being extended beyond the recommended time, user stories not being fully refined, and the sprint goal not being defined at the sprint planning meeting. The findings of this study provide valuable insights into the current state of Scrum methodology in software development organizations and highlight areas where there is room for improvement.

  • Exploring the relationship between investment choices, cognitive abilities risk attitudes and financial literacy
    • Muhammad Mushafiq
    2023 Journal of Economic and Administrative Sciences

    Purpose The main purpose of this study is to investigate the investment choices' relationship with cognitive abilities, risk aversion, risky investment intentions, subjective financial literacy and objective financial literacy. Design/methodology/approach To examine the relationship, two investment choices were given to 256 subjects from Pakistan. Questionnaire had total 20 questions for measuring five variables. To review this nexus, discriminant analysis was used as to explore the depth of the nexus that is the ability of the variables to predict the investment choices. Findings This study establishes the findings that Investment choices are guided by risk aversion, risky investment intentions, financial literacy (subjective and objective) and cognitive abilities. The risk aversion has negative relation to investment choices and other variables depict positive relationship to with investment choices. Practical implications This study provides a new and useful understanding into the existing literature on investment choices. The results are significant as the cognitive abilities show a positive contribution to the investment choices. This is point of significance as the portfolio managers and advisors would get help in regards of advising investments as they are aware what factors impact the investment choices. Originality/value This study is novel in its nature to evaluate investment choices using the cognitive ability alongside risk attitudes and financial literacy.

  • Exploring the Usability and User Experience of Social Media Apps through a Text Mining Approach
    • Anna Baj-Rogowska
    • Marcin Sikorski
    2023 Full text Engineering Management in Production and Services

    This study aims to evaluate the applicability of a text mining approach for extracting UUX-related issues from a dataset of user comments and not to evaluate the Instagram (IG) app. This study analyses textual data mined from reviews in English written by IG mobile application users. The article’s authors used text mining (based on the LDA algorithm) to identify the main UUX-related topics. Next, they mapped the identified topics with known theoretical constructs to place them in their nomological network relevant to the usability (the 5Es framework by Quesenbery) and UX (the Honeycomb model by Morville). Finally, to expand the study with an emotional diagnosis, sentiment analysis was performed on two levels: (i) for each recognised topic, and (ii) for the full dataset to uncover general insights into users’ emotions within all reviews. The case study of the IG app confirms the usefulness of user feedback data for software development and points out that the review data have the potential for the early detection of frustration and negative feelings introduced during the use of the application. Conducting conventional UUX evaluations with users is problematic since they are remotely located, and the user-generated content of a social app undergoes continuous and frequent changes. Thus, the consecutive stages of the proposed methodology, based on text mining algorithms, constitute a proposed framework for examining the user-perceived quality projection of applications from user feedback, and they are the main contribution of this article. The used approach can be valuable for helping developers, designers and researchers to reveal user problems and fulfil user satisfaction regarding UUX aspects for specific software features.

  • Export diversification and dependence on natural resources
    • Zuzanna Helena Zarach
    • Aleksandra Parteka
    2023 ECONOMIC MODELLING

    Low export diversification is a risk-augmenting factor for many countries dependent on natural resources. The literature tends to focus on the growth effects of resource dependence (‘resource curse’ debate) while not much is known on how it affects the variety of non-resource exports. To quantify this effect we decompose the relative Theil index using product-level export data from 160 countries over the time period 1996–2018. We reveal that most (above 70%) of low export diversification level is driven by the limited variety of products other than natural resources. At the same time, natural resource dependence (in particular on fossil fuels) correlates negatively with the diversification of the non-resource portion of the export basket, in particular of technologically advanced products. Econometric estimates with interaction terms and case studies of countries that managed to escape the resource trap show that institutional quality determines the ability of resource exporters to diversify.

  • Exposure scenario and risk assessment of infants and newborns to bisphenols and their derivatives from diapers
    • Aneta Chabowska
    • Natalia Jatkowska
    • Paweł Kubica
    • Justyna Płotka-Wasylka
    2023 Full text ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

    Newborns and infants are more sensitive to harmful compounds such as bisphenols and their derivatives because of their not fully developed detoxification mechanism. Exposure to these substances can lead to developmental problems and health consequences in adulthood. Since disposable baby diapers are used from the first days of life and remain in contact with the baby skin, it seems important to monitor the levels of endocrine disrupting chemicals (EDCs) in such products. Ultrasound assisted solvent microextraction of porous membrane-packed solid sample (UASE-PMSS) was used in sample preparation. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was used at determination step. Bisphenol A was quantified with the highest frequency at 81 % of samples tested, ranging from 5.0 to 520 ng/g. BADGE⋅2HCl was also quantified in high concentrations (from 6.8 to 530 ng/g), but was found in only 15 % of the tested samples. The daily exposure dose (DED) of bisphenols was calculated. In addition health risk assessment was conducted using previous (4 μg/kg BW) and actual (0.2 ng/kg BW) values of tolerable daily intake (TDI) of bisphenol A recommended by European Food Safety Authority (EFSA).

  • Extraction and Analysis of Bisphenols and Their Derivatives in Infant and Toddler Ready-to-feed Meals by Ultrasound-assisted Membrane Extraction Followed by LC MS/MS
    • Natalia Jatkowska
    • Paweł Kubica
    2023 Full text JOURNAL OF FOOD COMPOSITION AND ANALYSIS

    This research developed an ultrasound-assisted membrane extraction coupled with liquid chromatography-tandem mass spectrometry method for the determination of nineteen bisphenols and their derivatives in infant and toddler ready-to-feed meals. The calibration curves for all analytes were linear in the tested range, and the limit of detection and limit of quantitation were in the range 0.27 to 0.79 ng/g and 0.80 to 2.4 ng/g, respectively. The recovery values were in the range of 76 to 138%. This method was successfully applied to determine the content of bisphenols in 56 real samples of ready-to-eat meals for infants and toddlers. All of the analytes were quantified in at least one sample in the range of 1.0-371.9 ng/g. Mean exposures to bisphenols were estimated to be 9.01-769.49 ng/kg bw/day for both female and male babies. The health risk assessment revealed hazard quotient < 1, indicating that consumption of ready-to-eat meals is unlikely to pose any health risks to babies, even at the highest concentrations found in this study.