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  • Experimental comparison of the transition speed of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid
    • G.h.g. van der Meer
    • F. Quinci
    • Wojciech Litwin
    • Michał Wodtke
    • R.a.j. van Ostayen
    2023 Pełny tekst TRIBOLOGY INTERNATIONAL

    A journal bearing test bench is used to find the transition speed between the hydrodynamic and mixed lubrication regimes for a modified magnetorheological (MR) fluid. It is shown that the transition speed of the bearing can be reduced by applying a local magnetic field near minimum film when it is lubricated with the MR fluid, and that this will only marginally increase friction. The lubricating performance of the MR fluid is compared to that of a reference oil, and all experimental results are compared with a Finite Element model based on the Reynolds equation.

  • Experimental Evaluation of ND: YAG Laser Parameters and Sample Preparation Methods for Texturing Thin AISI 316L Steel Samples
    • Ewa Kozłowska
    • Sylwia Grabska-Zielińska
    2023 Pełny tekst Applied Sciences-Basel

    In mechanical and material engineering, the effect of laser texturing depends on many factors besides device specification, primarily the properties of the materials being processed, and, secondly, the preparation of the sample. Laser texturing of thin (<5 mm) samples is mostly performed utilizing short-pulse lasers, but depending on the power of the laser beam, the process can also be performed by using continuous operation lasers. When using a laser beam to modify the surface layer, special attention should be paid to the surface preparation process. Engraving a shiny metal surface can lead to laser beam dispersion and energy loss. Some materials require special preparation and surface darkening in order to be effectively engraved. In the case of engraving, maximizing the efficiency and repeatability of the process is the key to obtaining the desired properties. The aim of the conducted study was to establish satisfying parameters and a sample preparation method for texturing thin AISI 316L samples. Appropriately selected laser parameters added to proper sample preparation. The sanding, etching, and darkening of the surface layer improved the quality of the weld and eliminated problems such as deformation and spark formation that often occur with raw samples during the texturing process.

  • Experimental Investigation of the Performance of an Innovative Implantable Left Ventricular Assist Device—Proof of Concept
    • Krzysztof Tesch
    • Ryszard Jasiński
    • Leszek Dąbrowski
    • Jan Rogowski
    2023 Pełny tekst Applied Sciences-Basel

    This paper presents the results of experimental performance of an innovative left ventricular assist device working on a specially designed test stand. The introduced invention is mainly applied for supporting the heart in patients with end-stage heart failure accompanied by mitral valve regurgitation and pulmonary hypertension. Moreover, the developed device has the form of a flexible balloon forming an intracardiac inert gas-filled working chamber, which is divided into two smaller balloons (valve and ventricular) inflated with gas during use. In addition to supporting the heart, replacing the work of the left ventricle in a permanent manner is also possible. Furthermore, the designed test stand makes it possible to carry out realistic experiments in an environment resembling a human heart. Exemplary pressure measurements for hypotension and hypertension conditions are presented.

  • Experimental Investigations of Forced Convection of Nanofluids in Smooth, Horizontal, Round Tubes: A Review
    • Janusz Cieśliński
    • Przemysław Kozak
    2023 Pełny tekst ENERGIES

    A comprehensive review of published works dealing with experimental studies of forced convection heat transfer of nanofluids is presented. The survey is limited to straight, smooth, and round tubes. Moreover, only mono nanofluids exhibiting Newtonian behaviour are considered. Works on experimental research of forced convection in tubes are presented in a chronological order in the first part of the article. In this part, attention was paid to the influence of nanoparticles on the intensification of heat transfer. Information on the tested nanofluids, the measurement technique used, and the measurement range are presented in tabular form. Correlation equations proposed by individual researchers are also presented. In order to explain the controversy regarding the different influences of nanoparticles on the intensity of heat transfer during forced convection of nanofluids, the second part of the paper presents a comparison of the test results obtained by different researchers for the same nanofluid, possibly under the same thermal and flow conditions. Finally, the main conclusions are discussed.

  • Experimental investigations on the mechanical properties and damage detection of carbon nanotubes modified crumb rubber concrete
    • Suliman Khan
    • Shahzad Ashraf
    • Shehroze Ali
    • Khushal Khan
    2023 Pełny tekst Journal of Building Engineering

    This study presents a modified crumb rubber (MCR) concrete design mix reinforced with multi-walled carbon nanotubes (MWCNTs), mechanical characterization, and cracking monitoring using the acoustic emission (AE) technique. The results showed that the bridging effect of MWCNTs and MCR in the concrete mix mitigated the shortcomings of MWCNT-MCR concrete and improved the flexural and compressive strengths by 18.3% and 26.5%, respectively, at 28 days. The stress-strain behavior of the MWCNT-MCR concrete showed improved ductility (48.12%), axial strain (50.12%), and toughness (27.15%) compared to the reference specimens. The MWCNT–MCR concrete exhibited a mechanical response in three distinct loading phases. Overall, tensile failure (>4000 μs/v and >35 kHz) was observed in the tested specimens through the RA value (ratio of rise time to amplitude of AE waves) and average frequency (AF) distribution. Based on the amplitude distribution of the AE waves, the damping capacity of the MWCNT-MCR concrete was improved by 27.83%, and the fracture mechanism between micro and macro cracks was identified through a b-value approach. Finally, a regression model was established to predict the Ec of MWCNT-MCR concrete and the two-way interaction effect on the mechanical properties of the developed mix design.

  • Experimental review of the performances of protective coatings for interconnects in solid oxide fuel cells
    • Mareddy Jayanth Reddy
    • Bartosz Kamecki
    • Belma Talic
    • Elisa Zanchi
    • Federico Smeacetto
    • John S. Hardy
    • Jung Choi Choi
    • Łukasz Mazur
    • Robert Vaßen
    • Soumendra N. Basu
    • Tomasz Brylewski
    • Jan-Erik Svensson
    • Jan Froitzheim
    2023 Pełny tekst JOURNAL OF POWER SOURCES

    Ferritic stainless steel interconnects are used in solid oxide fuel cells; however, coatings are required to improve their performance. Although several types of coatings have been proposed, they have been scarcely investigated under similar conditions. This study compares the characteristics of uncoated Crofer 22 APU and eight different coatings on Crofer 22 APU for up to 3000 h at 800 ◦C. The coatings were deposited at various research laboratories around the world, and the experiments were performed at Chalmers University of Technology, Sweden. Cross-sections of the samples were analysed using scanning electron microscopy and energy-dispersive x-ray spectroscopy. The (Co,Mn)-based coated steels showed more than 50-fold lower chromium evaporation and at least 3 times thinner Cr2O3 scale thickness compared to uncoated steel. The coated steel samples showed lower area-specific resistance (ASR) values than the uncoated steel after 3000 h of exposure, irrespective of the coating thickness, composition and deposition method.

  • 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst

    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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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.

  • Extractive detoxification of hydrolysates with simultaneous formation of deep eutectic solvents
    • Patrycja Makoś-Chełstowska
    • Edyta Słupek
    • Karolina Kucharska
    • Jacek Gębicki
    2023 Pełny tekst Chemical and Process Engineering : New Frontiers

    The hydrolysis of lignocellulosic biomass results in the production of so-called fermentation inhibitors, which reduce the efficiency of biohydrogen production. To increase the efficiency of hydrogen production, inhibitors should be removed from aqueous hydrolysate solutions before the fermentation process. This paper presents a new approach to the detoxification of hydrolysates with the simultaneous formation of in-situ deep eutectic solvents (DES). In the first stage of the study, inhibitors were identified in the real hydrolysate samples using high-performance liquid chromatography (HPLC). Four monoterpenes were tested for their potential to extract furfural (FF) with simultaneous DES formation. An optimization process of the most important parameters affecting the extraction process and DES formation (Thymol:FF) was conducted using the Central Composite Design (CCD) model. A temperature of 40 ◦C, pH of 7, mHBD : mHYD ratio of 2:1, and time of 50 min were selected as the optimal conditions. These results indicate the high efficiency of FF removal from hydrolysates (92.1–94.6%) in a one-step process. Meanwhile, the structural properties of the formed DES measured by Fourier-transform infrared spectroscopy (FT-IR) and Nuclear magnetic resonance spectroscopy (NMR) differed only slightly from those of the DES composed of pure substances (Furfural and Thymol).

  • Fabrication and Characterization of Green Polyurethane Foams with Enhanced Vibration Damping Capability
    • Paulina Parcheta-Szwindowska
    • Karina Kopczyńska
    • Martyna Kordyzon
    • Janusz Datta
    2023 Pełny tekst ACS Sustainable Chemistry & Engineering

    Over the past decades, there has been an intensive development of the technologies and innovations aimed at increasing the quality of life. This development largely concerns the comfort of use of everyday products that, among others, are products of the automotive, construction, or furniture industries. Considering the increase in the comfort of using products such as cars, houses, and flats, one of the comfort features of their use is the ability to dampen the sounds coming from the outside. Currently, in addition to wood based boards, mineral wool, or glass wool fillings, polyurethane foams are more often used as oundproofing materials. This article describes the method of obtaining selected mechanical and thermal properties in flexible polyurethane foams with the ability to dampen vibrations, which were obtained with the use of raw materials of natural origin. The results of the tests of thermal stability and the vibration damping coefficient confirmed the possibility of using flexible polyurethane foams of natural origin as an alternative to the previously used vibration damping materials in the construction or the automotive industry.

  • Fabrication of wormhole-like YSZ and Ni-YSZ by the novel soft-hard template CTAB/NaCl-assisted route. Suppressing Ni coalescence in SOFC
    • Patryk Błaszczak
    • Agata Ducka
    • Barbara Wolanin
    • Krzysztof Matlak
    • Grzegorz Machowski
    • Marta Prześniak-Welenc
    • Sea-Fue Wang
    • Beata Bochentyn
    • Piotr Jasiński
    2023 Pełny tekst JOURNAL OF THE EUROPEAN CERAMIC SOCIETY

    A novel one-pot synthesis route leading to the formation of a wormhole-like structure was developed for the successful fabrication of porous YSZ and Ni-YSZ systems. This method involved co-precipitation in the presence of the micelle-forming agents CTAB/Pluronic P123 and crystallising NaCl. The obtained skeletons were mechanically stable and presented almost 50% uniform, open porosity without using any additional pore-formers. The fabricated 0.3 M CTAB/NaCl Ni-YSZ showed better long-term electrical stability in hydrogen than a traditional Ni-YSZ cermet. It resulted from the suppression of Ni structural changes throughout the anode scaffold. Moreover, higher electrochemical activity of this novel anode is expected due to the smaller particle sizes of Ni/YSZ, high homogeneity, highly developed TPB, and better interfacial interaction between the Ni and YSZ. Therefore, the novel soft-hard templating method is recognised as a promising route for the fabrication of the YSZ or Ni-YSZ with a highly developed microstructure and improved stability.

  • Facilitating free travel in the Schengen area—A position paper by the European Association for Biometrics
    • Christoph Busch
    • Farzin Deravi
    • Dinusha Frings
    • Els Kindt
    • Ralph Lessmann
    • Alexander Nouak
    • Jean Salomon
    • Mateus Achcar
    • Fernando Alonso-Fernandez
    • Daniel Bachenheimer
    • David Bethell
    • Josef Bigun
    • Matthew Brawley
    • Guido Brockmann
    • Enrique Cabello
    • Patrizio Campisi
    • Aleksandro Cepilovs
    • Miles Clee
    • Mickey Cohen
    • Christian Croll
    • Andrzej Czyżewski
    • Bernadette Dorizzi
    • Martin Drahansky
    • Paweł Drozdowski
    • Fankhauser Catherine
    • Julian Fierrez
    • Marta Gomez-Barrero
    • Georg Hasse
    • Richard Guest
    • Ekaterina Komleva
    • Sebastien Marcel
    • Gianluca Marcialis
    • Laurent Mercier
    • Emilio Mordini
    • Stefance Mouille
    • Pavlina Navratilova
    • Javier Ortega-Garcia
    • Dijana Petrovska
    • Norman Poh
    • Istvan Racz
    • Raghavendra Ramachandra
    • Christian Rathgeb
    • Christophe Remillet
    • Uwe Seidel
    • Luuk Spreeuwers
    • Brage Strand
    • Sirra Toivonen
    • Andreas Uhl
    2023 Pełny tekst IET Biometrics

    Due to migration, terror-threats and the viral pandemic, various EU member states have re-established internal border control or even closed their borders. European Association for Biometrics (EAB), a non-profit organisation, solicited the views of its members on ways which biometric technologies and services may be used to help with re-establishing open borders within the Schengen area while at the same time mitigating any adverse effects. From the responses received, this position paper was composed to identify ideas to re-establish free travel between the member states in the Schengen area. The paper covers the contending needs for security, open borders and fundamental rights as well as legal constraints that any technological solution must consider. A range of specific technologies for direct biometric recognition alongside complementary measures are outlined. The interrelated issues of ethical and societal considerations are also highlighted. Provided a holistic approach is adopted, it may be possible to reach a more optimal trade-off with regards to open borders while maintaining a high-level of security and protection of fundamental rights. European Association for Biometrics and its members can play an important role in fostering a shared understanding of security and mobility challenges and their solutions.

  • Factors affecting low-temperature cracking of asphalt pavements: analysis of field observations using the ordered logistic model
    • Dawid Ryś
    • Mariusz Jaczewski
    • Marek Pszczoła
    • Agnieszka Kamedulska
    • Bartosz Kamedulski
    2023 Pełny tekst International Journal of Pavement Engineering

    Accurate identification of factors that primarily affect the number of low-temperature cracks is crucial for selection of road materials and planning of pavement maintenance. Field investigations of lowtemperature cracks were performed in the years 2014 and 2020 on the same 68 road sections being in service in typical traffic conditions. The collected data were statistically analysed using the ordered logistic regression model. Comparison of the odds ratios which were calculated on the basis of the model enabled ordering of the selected factors from those having the greatest effect on lowtemperature cracking of pavements to those with the least influence: (1) pavement age, (2) type of asphalt concrete, (3) modification of bitumen, (4) climatic zone (on the basis of low performance grade temperature). The odds of a section belonging to the group of cracked sections decreased by half when a polymer-modified bitumen was used in its binder course and asphalt base. Regardless of the considered factors, the odds of a pavement section being classified into the group of heavily cracked sections are comparable. It means that some external factors, including quality of paving works and bitumen chemistry, may prove the most crucial.

  • Factors affecting the conclusion of an arrangement in restructuring proceedings: evidence from Poland
    • Błażej Prusak
    • Ulyana Zaremba
    • Paweł Galiński
    2023 Pełny tekst Ruch Prawniczy, Ekonomiczny i Socjologiczny

    The EU Restructuring Directive (2019/1023) requires Member States to provide a preventive restructuring framework for financially distressed entities that remain viable or are likely to readily restore economic viability. The first step to a successful restructuring is the approval of an arrangement between the debtor and creditors. The main research objective of the article is to identify factors affecting the conclusion of an arrangement in restructuring proceedings. In the process of filtering companies initiating a restructuring procedure, these factors are seen as increasing the probability of concluding an arrangement between debtor and creditors. Moreover, an additional research objective is to construct a turnaround prediction model aimed at assessing the probability of a conclusion of an arrangement in restructuring proceedings. The study covered the companies in Poland for which restructuring proceedings opened between 2016 and 2021 end-ed with the approval of an arrangement, and a similar number of companies that failed to restruc-ture successfully. Binary logistic regression was applied to achieve the aims of this study. The results show that two financial variables affected companies in terms of their chances to conclude the arrangement: the current ratio and return on assets were among the statistically significant indicators and they are characterized by higher values for debtors reaching the arrangement with their creditors. A direct positive relationship was also identified between the company’s lifespan and the outcome of the proceedings. The probability of the conclusion of the arrangement was also affected by the type of industry. Models assessing the probability of completing restructuring proceedings with an arrangement can be useful for insolvency practitioners and financial analysts during viability assessments.

  • FACTORS AFFECTING THE CONCLUSION OF AN ARRANGEMENT IN RESTRUCTURING PROCEEDINGS: EVIDENCE FROM POLAND
    • Błażej Prusak
    • Paweł Galiński
    2023 Pełny tekst

    The EU Restructuring Directive (2019/1023) requires Member States to provide a preventive restructuring framework for financially distressed entities that remain viable or are likely to readily restore economic viability. The first step to a successful restructuring is the approval of an arrangement between the debtor and creditors. The main research objective of the article is to identify factors affecting the conclusion of an arrangement in restructuring proceedings. In the process of filtering companies initiating a restructuring procedure, these factors are seen as increasing the probability of concluding an arrangement between debtor and creditors. Moreover, an additional research objective is to construct a turnaround prediction model aimed at assessing the probability of a conclusion of an arrangement in restructuring proceedings. The study covered the companies in Poland for which restructuring proceedings opened between 2016 and 2021 ended with the approval of an arrangement, and a similar number of companies that failed to restructure successfully. Binary logistic regression was applied to achieve the aims of this study. The results show that two financial variables affected companies in terms of their chances to conclude the arrangement: the current ratio and return on assets were among the statistically significant indicators and they are characterized by higher values for debtors reaching the arrangement with their creditors. A direct positive relationship was also identified between the company's lifespan and the outcome of the proceedings. The probability of the conclusion of the arrangement was also affected by the type of industry. Models assessing the probability of completing restructuring proceedings with an arrangement can be useful for insolvency practitioners and financial analysts during viability assessments.

  • Factors Affecting the Rheological Properties of Foods
    • Robert Tylingo
    2023

    In this chapter, engineering aspects concerning real body mechanics and the impact of respective food ingredients on said properties are presented together. Food is a complex matrix and each of macro and micro ingredients plays its role in the formation of rheologic properties, and minor changes in the basic ingredient structure may affect the change of these properties significantly. Basic analytic techniques are presented for the assessment of rheologic parameters. Furthermore, this chapter includes the evaluation of the impact of selected food ingredients, such as: proteins, saccharides, lipids on the creation of measurable, rheologic parameters of food products and their modification possibilities.

  • Failure characterisation of sandwich beams using integrated acoustic emission and digital image correlation techniques
    • Łukasz Pyrzowski
    • Magdalena Knak
    • Magdalena Rucka
    2023 Pełny tekst COMPOSITE STRUCTURES

    The paper presents the experimental study of the failure behaviour of sandwich beams subjected to bending. The samples examined are sandwich beams made of polyethylene terephthalate foam core and glass fibre-reinforced polymer laminate face sheets. In a series of experiments, it has been proposed to integrate diagnostic techniques with acoustic emission and digital image correlation to accurately track the cracking process on the surface as well as in the entire volume of the beam. The research programme carried out allowed observing various modes of failure in composite specimens. The results obtained showed that the integration of acoustic and optical diagnostic techniques provided complementary results and can be used successfully for failure monitoring in sandwich beams.

  • Fashion and Tourism: Parallel Stories of Two "Dream Marvels".
    • Maria Gravari-Barbas
    • Nadzeya Sabatini
    2023

    Fashion and tourism are two social, cultural, and economic phenomena that have both numerous connections and surprising similarities. These are not new: they have been built and developed since the beginnings of tourism as a modern social phenomenon, emerged in Europe in the context of the industrial revolution. They consolidated in the first decades of the 21st century, in a context where both phenomena have completed their “mass” cycle and are currently seeking alternative ways of expression and development. The chapter analyzes first the common characteristics of these two phenomena, fashion and tourism, as well as the challenges they are facing in the beginning of the 21st century. What can one learn from these proximities? What does the evolution of the practices, policies, and space planning of one phenomenon say about the other?

  • Fashion Games, Fashion in Games and Gamification in Fashion. A First Map
    • Alice Noris
    • Nadzeya Sabatini
    • Lorenzo Cantoni
    2023

    Fashion companies have been using different forms of entertainment such as film and television, sport, music, museums, and photography as inspiration sources and as communication and marketing channels for decades. However, in recent years, they have also started to consider the gaming world. While gaming offers a potential revenue stream from sales of physical and digital clothing, change in it is also the gateway to access new opportunities of the so-called metaverse. Moreover, the development of mixed realities might, in a sense, “democratize” the industry by offering at a lower price the digital version of products that attract customers. Through an analysis of secondary data and the study of three cases, this research aims to understand how fashion companies adopt and adapt digital games to develop their communication and marketing strategies, and how gaming companies exploit fashion to develop their products. The main goal is to analyze from an academic perspective how the gaming industry represents a communication and marketing channel in which creative companies can produce immersive experiences different from those available through other means. Finally, this article provides a map of the relationships between fashion and gaming by proposing three categories: gamification in fashion, fashion games and fashion in games.

  • Fast Algorithms for Identification of Time-Varying Systems with Both Smooth and Discontinuous Parameter Changes
    • Maciej Niedźwiecki
    • Artur Gańcza
    2023 Pełny tekst

    The problem of noncausal identification of a time-varying linear system subject to both smooth and occasional jump-type changes is considered and solved using the preestimation technique combined with the basis function approach to modeling the variability of system parameters. The proposed estimation algorithms yield very good parameter tracking results and are computationally attractive.

  • Fast Calibration-Free Single-Anchor Indoor Localization Based on Limited Number of ESPAR Antenna Radiation Patterns
    • Mateusz Groth
    • Krzysztof Nyka
    • Łukasz Kulas
    2023

    — In this article, we investigate how the calibrationfree single-anchor indoor localization algorithm developed for base stations equipped with electronically steerable parasitic array radiator (ESPAR) antennas can further be improved. By reducing the total number of ESPAR antenna radiation patterns used in localization process, one can significantly reduce the time needed for an object localization. Performed localization measurements involved different placement and number of reference nodes (RNs) used by the calibration-free singleanchor indoor localization algorithm, as well as different possible radiation patterns sets involving 6, 4 or 3 radiation patterns. Test results show that without significant deterioration of the overall accuracy one can easily speed up the algorithm execution time.

  • Fatigue life prediction of notched components under size effect using strain energy reformulated critical distance theory
    • Zhouyang Shuai
    • Shun-Peng Zhu
    • Jin-Chao He
    • Ding Liao
    • José A.F.O. Correia
    • Wojciech Macek
    • Ricardo Branco
    • Qingyuan Wang
    2023 INTERNATIONAL JOURNAL OF FATIGUE

    Notch and size effects show significant impact on the fatigue performance of engineering components, which deserves special attention. In this work, a strain energy reformulated critical distance theory was developed for fatigue life prediction of notched components under size effect. Experimental data of different notched specimens manufactured from GH4169, TC4, TC11 alloys and low carbon steel En3B were used for model validation and comparison. Results indicate the proposed model works better than the Yang’s and the Shen’s models.

  • Fatty acids as molecular carriers in cleavable antifungal conjugates
    • Michał Nowak
    • Andrzej Skwarecki
    • Joanna Pilch
    • Justyna Górska
    • Piotr Szweda
    • Maria Milewska
    • Sławomir Milewski
    2023 Pełny tekst EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY

    Conjugates composed of C2-18 fatty acid (FA) residues as a molecular carrier and 5-fluorocytosine (5-FC) as an active agent, released upon the action of intracellular esterases on the ester bond between FA and “trimethyl lock” intramolecular linker, demonstrate good in vitro activity against human pathogenic yeasts of Candida spp. The minimal inhibitory concentrations (MIC) values for the most active conjugates containing caprylic (C8), capric (C10), lauric (C12), or myristic (C14) acid residues were in the 2–64 μg mL.

  • Fault detection and diagnostics of complex dynamic systems using Gaussian Process Models - nuclear power plant case study
    • Bartosz Puchalski
    2023

    The article examines the use of Gaussian Process Models to simulate the dynamic processes of a Pressurized Water nuclear Reactor for fault detection and diagnostics. The paper illustrates the potential of Gaussian Process Models as a tool for monitoring and predicting various fault conditions in Pressurized Water nuclear Reactor power plants, including reactor coolant flow and temperature variations, deviations from nominal working point or faulty power measurements. The article discusses the characteristics and benefits of Gaussian Process Models and how they can be utilized to improve: the reliability and accuracy of nuclear power plant anomaly detection, fault diagnosis and decision making process in states of emergency. Overall, this paper highlights the capabilities of Gaussian Process Models to enhance the safety, reliability and efficiency of nuclear power plants. The results of this study are expected to provide valuable insights for engineers and researchers in the fields of control engineering and nuclear power.

  • FDTD Method for Electromagnetic Simulations in Media Described by Time-Fractional Constitutive Relations
    • Piotr Pietruszka
    • Tomasz Stefański
    • Jacek Gulgowski
    2023 Pełny tekst Applied Sciences-Basel

    In this paper, the finite-difference time-domain (FDTD) method is derived for electromagnetic simulations in media described by the time-fractional (TF) constitutive relations. TF Maxwell’s equations are derived based on these constitutive relations and the Grünwald–Letnikov definition of a fractional derivative. Then the FDTD algorithm, which includes memory effects and energy dissipation of the considered media, is introduced. Finally, one-dimensional signal propagation in such electromagnetic media is considered. The proposed FDTD method is derived based on a discrete approximation of the Grünwald–Letnikov definition of the fractional derivative and evaluated in a code. The stability condition is derived for the proposed FDTD method based on a numerical dispersion relation. The obtained numerical results are compared with the outcomes of reference frequency-domain simulations, proving the accuracy of the proposed approach. However, high spatial resolution is required in order to obtain accurate results. The developed FDTD method is, unfortunately, computation and memory demanding when compared to the ordinary FDTD algorithm.

  • Feasibility Study of Biohydrogen Production from Acid Cheese Whey via Lactate-Driven Dark Fermentation
    • Brenda Aranda-Jaramillo
    • Elizabeth León-Becerril
    • Oscar Aguilar-Juárez
    • Roberto Castro Munoz
    • Octavio García-Depraect
    2023 Pełny tekst Fermentation

    The high loading of lactic acid bacteria (LAB) present in cheese whey still limits its use as hydrogen feedstock. This study aims to investigate the feasibility of producing hydrogen from acid cheese whey via lactate-driven dark fermentation (LD-DF). Mesophilic batch fermentations were performed with delipidated acid cheese whey at a fixed pH of 5.8 and driven by an acidogenic bacterial culture containing LAB and lactate-oxidizing hydrogen producers (LO-HPB). The results obtained indicated that it is technically feasible to produce hydrogen from undiluted cheese whey through lactate oxidation-mediated fermentation. It was elucidated that the acidogenic fermentation of cheese whey followed a two-step lactate-type fermentation, in which fermentable carbohydrates were first converted into lactate, and then lactate was metabolized into hydrogen with the co-production of butyrate. The hydrogen yield and the maximum volumetric hydrogen production rate achieved were 44.5 ± 2.9 NmL/g-CODfed and 1.9 NL/L-d, respectively. Further microbial community analysis revealed that Lactobacillus, Clostridium, and Klebsiella were the dominant bacterial genera when the hydrogen production rate peaked. It was therefore suggested that the metabolic potential behind the association between LAB and LO-HPB was important in driving the two-step lactate-type fermentation. Overall, the LD-DF can be a strategic hydrogen-producing pathway to be implemented with cheese whey.

  • Federated Learning in Healthcare Industry: Mammography Case Study
    • Krystian Zieliński
    • Natalia Kowalczyk
    • Tomasz Kocejko
    • Magdalena Mazur-Milecka
    • Tomasz Neumann
    • Jacek Rumiński
    2023

    The paper focuses on the role of federated learning in a healthcare environment. The experimental setup involved different healthcare providers, each with their datasets. A comparison was made between training a deep learning model using traditional methods, where all the data is stored in one place, and using federated learning, where the data is distributed among the workers. The experiment aimed to identify possible challenges that could arise when training a model in a federated learning scenario, including the impact of federated learning on the obtained measures for breast density classification and examining the impact of data preprocessing and domain adaptation. The results indicate that using federated learning deep-learning models can be effectively trained on distributed healthcare data, performing similarly to the traditional approach while providing additional benefits such as improved data privacy and security. However, domain adaptation and data heterogeneity must be carefully addressed to achieve optimal performance in federated learning.

  • FEM modelling of screw displacement pile interaction with subsoil
    • Paweł Więcławski
    • Adam Krasiński
    2023 Pełny tekst Archives of Civil Engineering

    Predicting the-settlement characteristics of piles is an important element in the designing of pile foundations. The most reliable method in evaluating pile-soil interaction is the static load test, preferably performed with instrumentation for measuring shaft and pile base resistances. This, however, is a mostly post-implementation test. In the design phase, prediction methods are needed, in which numerical simulations play an increasingly popular role. This article proposes a procedure for numerically modeling the interaction of screw displacement piles with soil using the ZSoil 2D FEM program. The procedure takes into account technological characteristics of this type of pile, such as the process of soil expansion during the screwing-in of the auger and the pressure of concrete mix after pile concreting. They significantly affect the soil stress state, which is a key parameter for the pile load capacity. Geotechnical parameters of the subsoil were adopted from CPTU probing and laboratory tests. Due to the physical complexity, a constitutive soil model "Hardening Soil" (HS) was used in the analyses. The modeling procedure was calibrated on the basis of the static load test results of several instrumented piles, which were carried out as part of the "DPDT-Auger" research project. As a result of these calibrations, generalized recommendations were derived for an entire single pile modeling process with the axisymmetric system of ZSoil program. These can be useful in the reliable FEM prediction of the-characteristics for screw displacement piles for practical engineering purposes.

  • Fe-modified Mn2CuO4 spinel oxides: coatings based on abundant elements for solid oxide cell interconnects
    • Justyna Ignaczak
    • Lunjie Zeng
    • Dario Ferreira Sanchez
    • Małgorzata Makowska
    • Karolina Górnicka
    • Krystian Lankauf
    • Jakub Karczewski
    • Piotr Jasiński
    • Sebastian Molin
    2023 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    The current state of the art steel interconnect coating materials are based on critical raw material - Co-oxide spinels. Replacing Co-oxide spinels with alternative, abundant materials can reduce the dependence on the critical raw materials. Cobalt-free coatings with the general formula Mn2-xCuFexO4, where x = 0, 0.1, 0.3, were electrophoretically deposited on a ferritic stainless-steel support and evaluated. Prior to deposition, the powders were prepared by a soft chemistry process and studied in terms of crystallographic phase analysis, electrical conductivity, thermal expansion, and sinterability behaviour. Coated steel samples were oxidised in an air atmosphere at 750 °C for 3000 h. In parallel, a state-of-the-art MnCo2O4 spinel oxide was tested as a reference. The coatings and oxide scale microstructures of the surfaces and cross-sections were examined by XRD, and SEM-EDX. TEM-EDX, XRF, and micro-XRD were also performed on the cross-section lamellae. The electrical properties of the steel-coating system were evaluated by Area Specific Resistance measurement. The results confirm that Mn–Cu–Fe oxides exhibit higher conductivity and lower TEC than Mn–Co oxide. Based on the obtained results, it might be concluded that the proposed coatings are a promising alternative to coatings that contain cobalt.

  • Fibrillar aggregates in powdered milk
    • Jarosław Wawer
    • Martyna Andrukajtis
    • Jakub Karczewski
    • Anna Zielińska-Jurek
    • Rafał Piątek
    2023 JOURNAL OF DAIRY RESEARCH

    This research paper addresses the hypothesis that powdered milk may contain amyloid fibrils. Amyloids are fibrillar aggregates of proteins. Up to this time, research on the presence of amyloids in food products are scarce. To check the hypothesis we performed thioflavin T fluorescence assay, X-ray powder diffraction, atomic force microscopy and fluorescence microscopy imaging. Our preliminary results show that commercially available milks contain fibrils that have features characteristic to amyloids. The obtained results can be interpreted in two opposite ways. The presence of amyloids could be considered as a hazard due to the fact that food products may induce amyloid related diseases. On the other hand, the presence of amyloids in traditionally consumed foodstuffs could serve as proof that fibrils of food proteins do not pose a threat for consumers.

  • Filter-Hilbert Method for Automatic Correction of Non-Anechoic Antenna Measurements with Embedded Self-Calibration Mechanism
    • Adrian Bekasiewicz
    • Vorya Waladi
    2023 MEASUREMENT

    One of the most important steps in the process of antenna development involves measurements of its prototype. Far-field performance of radiators is normally characterized in strictly controlled environments such as anechoic chambers which can ensure certification-grade accuracy. Unfortunately, they are also characterized by high construction costs which might not be justified for low-budget research and/or teaching-related activities. Alternatively, the radiation characteristics can be obtained in non-anechoic test sites which neglect the expensive components such as shielding and/or absorbing materials. Although the noise from external radiation sources and multi-path interferences renders direct measurements in such conditions useless for drawing conclusions on antenna performance, the quality of responses can be substantially increased using appropriate post-processing. Unfortunately, the existing techniques are difficult to set-up and prone to failure which makes them of limited use for day-to-day measurements. In this work, a correction framework for non-anechoic measurements based on a set of Hilbert filters automatically adapted to propagation conditions within the test-site has been proposed. The presented method has been validated based on three example antennas and a total of 25 experiments covering 15 unique frequencies of interest. A benchmark of the method against the state-of-the-art correction techniques has also been performed.

  • Financial aspects of supporting Ukrainian refugees
    • Krystyna Gomółka
    • Piotr Kasprzak
    2023

    Warfare in Ukraine meant that in 2022 many countries, including Poland and other European, focused mainly on helping refugees from Ukraine and humanitarian transports. The assistance took on various forms - from basic humanitarian support, through in-kind help, financial and military assistance. Poland launched its humanitarian aid in the first days of the conflict. The aid provided by each country varies. It should be noted, however, that in each case it is possible to quantify it economically, i.e. to determine its scope, role and importance, and above all, its economic (financial) dimension. The aim of this article is to present various forms of assistance from European countries, with particular emphasis on Poland. As part of the research, the latest available literature on the subject, industry reports and sometimes press articles were used.