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Gdańsk University of Technology

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  • Czynniki kształtujące skuteczność outsourcingu w podmiotach leczniczych
    • Piotr Grudowski
    • Mateusz Muchlado
    2023

    Problem badawczy podjęty przez autorów tej książki można więc sformułować następująco: Jakie procesy podlegają outsourcingowi i jakie czynniki decydują o ich skuteczności w szpitalach w Polsce? W konsekwencji celem badawczym przyjętym w niniejszej pracy jest identyfikacja procesów zlecanych na zewnątrz w polskich szpitalach wraz z czynnikami warunkującymi ich skuteczność. Celem utylitarnym jest zaś opracowanie metody umożliwiającej kadrze zarządzającej polskimi szpitalami dobór dostawców oraz ocenę procesów poddanych outsourcingowi. Niniejsza monografia składa się z trzech głównych rozdziałów. W rozdziale 1 omówiono pojęcie outsourcingu oraz wykorzystanie go w zarządzaniu procesami. Opisano też czynniki sprawiające, że organizacje decydują się na zlecanie procesów na zewnątrz, jak również szanse i zagrożenia z tym związane. Przedstawiono charakterystykę podejścia procesowego, a także metody klasyfikacji procesów, których zastosowanie jest niezbędne przy wydzielaniu procesu na zewnątrz. Scharakteryzowano też najczęściej wykorzystywane w praktyce oraz sugerowane w literaturze przedmiotu metody oceny skuteczności procesów. W rozdziale 2 przedstawiono organizacje stanowiące podmiot badań oraz ich charakterystykę w świetle literatury. Zawarto tu również wnioski płynące z przeglądu literatury dotyczącej outsourcingu w podmiotach leczniczych w Polsce i za granicą, które odnoszą się do rodzaju procesów wydzielanych oraz motywów prowadzących do outsourcingu. Opisano uwarunkowania prawne i normatywne wpływające na wybór dostawcy outsourcingowego i ocenę skuteczności procesów poddanych outsourcingowi. W rozdziale 3 przedstawiono zastosowaną przez autorów metodykę badawczą. Zaprezentowano wybrane wyniki badań, które posłużyły do weryfikacji postawionych hipotez, a także do osiągnięcia celu utylitarnego, czyli opracowania metody oceny skuteczności procesów poddanych outsourcingowi. Metoda ta została omówiona w końcowej. części rozdziału. W podsumowaniu przedstawiono ujęte syntetycznie wyniki przeprowadzonych badań, wnioski i rekomendacje, w tym te związane z funkcjonowaniem placówek ochrony zdrowia w warunkach kryzysu i niepewności. Książka adresowana jest przede wszystkim do osób zajmujących się zarządzaniem w sektorze ochrony zdrowia, zarówno praktyków, jak i badaczy tej problematyki. Powinna się też spotkać z zainteresowaniem studentów kierunków związanych z zarządzaniem w usługach publicznych.

  • Data, Information, Knowledge, Wisdom Pyramid Concept Revisited in the Context of Deep Learning
    • Bożena Kostek
    2023

    In this paper, the data, information, knowledge, and wisdom (DIKW) pyramid is revisited in the context of deep learning applied to machine learningbased audio signal processing. A discussion on the DIKW schema is carried out, resulting in a proposal that may supplement the original concept. Parallels between DIWK pertaining to audio processing are presented based on examples of the case studies performed by the author and her collaborators. The studies shown refer to the challenge concerning the notion that classification performed by machine learning (ML) is/or should be better than human-based expertise. Conclusions are also delivered.

  • Data-driven, probabilistic model for attainable speed for ships approaching Gdańsk harbour
    • Jakub Montewka
    • Marcin Życzkowski
    • Filip Zarzycki
    2023

    The growing demand for maritime transportation leads to increased traffic in ports. From this arises the need to observe the consequences of the specific speed ships reach when approaching seaports. However, usually the analyzed cases refer only to the statistical evaluation of the studied phenomenon or to the empirical modelling, ignoring the mutual influence of variables such as ship type, length or weather conditions. In this paper, a different approach to the issue is proposed, which summarizes the most important factors and leads to a probabilistic speed model for manoeuvring ships in the port of Gdańsk. For this purpose, data from the Automatic Identification System were used. This resulted in a dataset with almost 2.5k traffic scenarios. To obtain results from the dataset, three different machine learning algorithms based on Bayesian networks were then applied. The developed models can be used to predict the speed as a function of the given parameters as well as to determine the values of individual parameters for a given speed. In addition, the use of the constructed models allowed the analysis of the strength of mutual influences for two connected nodes or the sensitivity of changes for individual variables. The discussion also raised questions about validation of the algorithms and measures to improve accuracy. The average predictive accuracy of the models of about 75% (depending on the learning algorithm used) achieved at this stage is promising, but further work is expected that can increase the predictive power of the models.

  • Data-Driven Surrogate-Assisted Optimization of Metamaterial-Based Filtenna Using Deep Learning
    • Peyman Mahouti
    • Aysu Belen
    • Ozlem Tari
    • Mehmet Belen
    • Serdal Karahan
    • Sławomir Kozieł
    2023 Full text Electronics

    In this work, a computationally efficient method based on data driven surrogate models is pro-posed for the design optimization procedure of a Frequency Selective Surface (FSS)-based filtering antenna (Filtenna). A Filtenna acts as a as module that simultaneously pre-filters unwanted sig-nals, and enhances the desired signals at the operating frequency. However, due to a typically large number of design variables of FSS unit elements, and their complex interrelations affecting the scattering response, FSS optimization is a challenging task. Herein, a deep-learning-based al-gorithm, Modified-Multi-Layer-Perceptron (M2LP), is developed to render an accurate behavioral model of the unit cell. Subsequently, the M2LP model is applied to optimize FSS elements being parts of the Filtenna under design. The exemplary device operates at 5 GHz to 7 GHz band. The numerical results demonstrate that the presented approach allows for almost 90% reduction of the computational cost of the optimization process as compared to direct EM-driven design. At the same time, physical measurements of the fabricated Filtenna prototype corroborate the relevance of the proposed methodology. One of the important advantages of our technique is that the unit cell model can be re-used to design FSS and Filtenna operating a various operating bands without incurring any extra computational expenses.

  • Dataset Related Experimental Investigation of Chess Position Evaluation Using a Deep Neural Network
    • Dawid Wieczerzak
    • Paweł Czarnul
    2023 Full text

    The idea of training Articial Neural Networks to evaluate chess positions has been widely explored in the last ten years. In this paper we investigated dataset impact on chess position evaluation. We created two datasets with over 1.6 million unique chess positions each. In one of those we also included randomly generated positions resulting from consideration of potentially unpredictable chess moves. Each position was evaluated by the Stockfish engine. Afterwards, we created a multi class evaluation model using Multilayer Perceptron. Solution to the evaluation problem was tested with three different data labeling methods and three different board representations. We show that the accuracy for the model trained for the dataset without randomly generated positions is higher than for the model with such positions, for all data representations and 3, 5 and 11 evaluation classes.

  • Debonding of coin-shaped osseointegrated implants: Coupling of experimental and numerical approaches
    • Yoann Hériveaux
    • Sophie Le Cann
    • Katharina Immel
    • Elsa Vennat
    • Vu-Hieu Nguyen
    • Vladimir Brailovski
    • Patrick Karasinski
    • Roger Sauer
    • Guillaume Haiat
    2023 Journal of the Mechanical Behavior of Biomedical Materials

    While cementless implants are now widely used clinically, implant debonding still occur and is difficult to anticipate. Assessing the biomechanical strength of the bone–implant interface can help improving the understanding of osseointegration phenomena and thus preventing surgical failures. A dedicated and standardized implant model was considered. The samples were tested using a mode III cleavage device to assess the mechanical strength of the bone-implant interface by combining experimental and numerical approaches. Four rough (Sa = 24.5 μm) osseointegrated coin-shaped implants were left in sheep cortical bone during 15 weeks of healing time. Each sample was experimentally rotated at 0.03◦/sec until complete rupture of the interface. The maximum values of the torque were comprised between 0.48 and 0.72 Nm, while a significant increase of the normal force from 7-12 N to 31–43 N was observed during the bone-implant interface debonding, suggesting the generation of bone debris at the bone-implant interface. The experimental results were compared to an isogeometric finite element model describing the adhesion and debonding phenomena through a modified Coulomb’s law, based on a varying friction coefficient to represent the transition from an unbroken to a broken bone-implant interface. A good agreement was found between numerical and experimental torques, with numerical friction coefficients decreasing from 8.93 to 1.23 during the bone-implant interface rupture, which constitutes a validation of this model to simulate the debonding of an osseointegrated bone-implant interface subjected to torsion.

  • Decomposition of the induced magnetism degaussing problem for fast determination of currents in demagnetization coils wrapped outside an object under arbitrary external field conditions
    • Mirosław Wołoszyn
    • Jarosław Tarnawski
    • Joanna Wołoszyn
    2023 Full text JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

    Safe passage of ships in the presence of sea mines can be ensured by limiting or reducing the ship’s magnetic footprint. For vessels with plastic hulls, the main component that requires magnetic damping is the engine. Demagnetization of such an object can be achieved by wrapping it with coils and setting the direct current appropriately. For each specific geographic location, the currents in the coils can be determined iteratively from measurements of the magnetic signature in the cardinal directions. In this paper the magnetic signatures are calculated using decomposition-based approach for each coil and each component of the external field separately. Hence the overall magnetic signature of the object can be reproduced in arbitrary external magnetic field (i.e. anywhere on the Earth). Knowing the influence of each coil, it is possible to formulate the optimization task (signature minimization) and determine the currents. The presented method is verified in FEM software with the use of engine models of both symmetrical and asymmetrical shapes. Since the determination of the currents takes place as a result of solving the optimization problem, the effectiveness of obtaining the results, the speed of convergence and the dependence on initial conditions is under investigation. The effect of the model mesh size on the quality of object signature reduction is also analyzed. The developed method can be used for a real object. In that case acquiring the data then requires the measurements of the object placed inside the Helmholtz coils.

  • Deep eutectic solvents – Ideal solution for clean air or hidden danger?
    • Farooque Janjhi
    • Roberto Castro Munoz
    • Grzegorz Boczkaj
    2023 SEPARATION AND PURIFICATION TECHNOLOGY

    The industrial sector is one of the fastest-growing sources of greenhouse gases, due to its excessive energy consumption to meet the rapidly growing demand for energy-intensive products. The use of deep eutectic solvents (DESs) has been studied extensively in order to cope with these harmful gases, but their usage can be an issue in respect to ecological reasons. Do deep eutectic solvents harm the atmosphere? Yes, these solvents can be harmful if their constituents (HBA and HBD) that are volatile and toxic in nature. A number of scientific reports preset their application without care on cross-contamination of treated media. Herein, we highlight the ecotoxicity behavior of DESs as treatment materials for three major toxic gas treatment methods, including carbon dioxide (CO2) capture, biogas treatment and air purification. Special attention is given to the health consequences of HBDs due to their toxicity and emission outside of the treatment system into the environment. The physicochemical characteristics of DESs are evaluated and addressed in comparison to the benchmark solvents. Emission of DESs can be predicted based on simulation software like COSMO-RS or Molecular Dynamics (MD). Furthermore, we suggest some simple protocols to estimate this issue and thus make aware researchers to think about it when experimenting with DES for different applications.

  • Deep eutectic solvents in analytical sample preconcentration Part B: Solid-phase (micro)extraction
    • Justyna Werner
    • Agnieszka Zgoła-Grześkowiak
    • Julia Płatkiewicz
    • Justyna Płotka-Wasylka
    • Natalia Jatkowska
    • Alina Kalyniukova
    • Serhii Zaruba
    • Vasil Andruch
    2023 MICROCHEMICAL JOURNAL

    One of the key challenges of modern analytical chemistry is the monitoring of trace amounts of contaminants using sensitive and selective instrumental techniques. Due to the variety and complexity of some samples, it is often necessary to properly prepare a sample and to perform a preconcentration of trace amounts of analytes. In line with the principles of Green Analytical Chemistry (GAC), it is important for an analytical procedure to reduce labor and time consumption and to decrease the use of volatile and hazardous solvents. Therefore, solvent-free extraction techniques, such as SPE, μSPE, SPME and their various modifications, which are mainly aimed at increasing their “greenness”, have been very popular for many years. Deep eutectic solvents fit perfectly into GAC principles, which is why they have been used as extractants in liquid-phase microextraction techniques for a long time. This review is a follow-up to our recently published article on the use of deep eutectic solvents (DESs) in liquid-phase microextraction techniques and summarizes the most important applications of DES in solid-phase (micro)extraction techniques.

  • Deep Eutectic Solvents: Properties and Applications in CO2 Separation
    • Iwona Cichowska-Kopczyńska
    • Bartosz Nowosielski
    • Dorota Warmińska
    2023 Full text MOLECULES

    Nowadays, many researchers are focused on finding a solution to the problem of global warming. Carbon dioxide is considered to be responsible for the “greenhouse” effect. The largest global emission of industrial CO2 comes from fossil fuel combustion, which makes power plants the perfect point source targets for immediate CO2 emission reductions. A state-of-the-art method for capturing carbon dioxide is chemical absorption using an aqueous solution of alkanolamines, most frequently a 30% wt. solution of monoethanolamine (MEA). Unfortunately, the usage of alkanolamines has a number of drawbacks, such as the corrosive nature of the reaction environment, the loss of the solvent due to its volatility, and a high energy demand at the regeneration step. These problems have driven the search for alternatives to that method, and deep eutectic solvents (DESs) might be a very good substitute. Many types of DESs have thus far been investigated for efficient CO2 capture, and various hydrogen bond donors and acceptors have been used. Deep eutectic solvents that are capable of absorbing carbon dioxide physically and chemically have been reported. Strategies for further CO2 absorption improvement, such as the addition of water, other co-solvents, or metal salts, have been proposed. Within this review, the physical properties of DESs are presented, and their effects on CO2 absorption capacity are discussed in conjunction with the types of HBAs and HBDs and their molar ratios. The practical issues of using DESs for CO2 separation are also described.

  • Deep-Learning-Based Precise Characterization of Microwave Transistors Using Fully-Automated Regression Surrogates
    • Nurullah Calik
    • Filiz Gunes
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Mehmet Belen
    • Peyman Mahouti
    2023 Full text Scientific Reports

    Accurate models of scattering and noise parameters of transistors are instrumental in facilitating design procedures of microwave devices such as low-noise amplifiers. Yet, data-driven modeling of transistors is a challenging endeavor due to complex relationships between transistor characteristics and its designable parameters, biasing conditions, and frequency. Artificial neural network (ANN)-based methods, including deep learning (DL), have been found suitable for this task by capitalizing on their flexibility and generality. Yet, rendering reliable transistor surrogates is hindered by a number of issues such as the need for finding good match between the input data and the network architecture and hyperparameters (number and sizes of layers, activation functions, data pre-processing methods), possible overtraining, etc. This work proposes a novel methodology, referred to as Fully Adaptive Regression Model (FARM), where all network components and processing functions are automatically determined through Tree Parzen Estimator. Our technique is comprehensively validated using three examples of microwave transistors and demonstrated to offer a competitive edge over the state-of-the-art methods in terms of modeling accuracy and handling the aforementioned issues pertinent to standard ANN-based surrogates.

  • Deformation of an elastic second gradient spherical body under equatorial line density of dead forces
    • Isola dell'Isola
    • Victor Eremeev
    • V Korolenko
    • Yuri Solyaev
    2023 EUROPEAN JOURNAL OF MECHANICS A-SOLIDS

    We consider deformations of an elastic body having initially a spherical shape. Assumed deformation energy depends on the first and second gradient of displacements. We apply an equatorial line density of dead loads, that are forces per unit line length directed in radial direction and applied along the equator of the sphere. We restrict ourselves our analysis to the case of linearized second strain gradient isotropic elasticity (for which the more general energy was determined by Mindlin) with only one characteristic length. Differently to what happens in first gradient continua, i.e. in classic linear elasticity, we show that for the particular class second gradient continua considered here these forces do not determine infinite displacements in the direction of applied dead line forces. Instead, using a series method for the solution of the considered boundary-value problem, we demonstrate that the displacements are finite. So in the deformed configuration there is not the formation of an edge at the material points where the forces are applied. Further investigations are therefore needed for establishing if this elastic-regime edge formation is made possible: (I) either in the case of more general linear elastic constitutive equations or (II) only when large deformations are considered or (III) if non-elastic phenomena are involved.

  • Degradation of bisphenol S – a contaminant of emerging concern - by synergistic ozone and percarbonate based AOP
    • Zahra Askarniya
    • Manoj P Rayaroth
    • Xun Sun
    • Zhaohui Wang
    • Grzegorz Boczkaj
    2023 Full text Water Resources and Industry

    Degradation of bisphenol S was studied using ozone activated by sodium percarbonate and the effectiveness of optimized process was compared with the peroxone process. The influence of several factors including sodium percarbonate concentration, ozone dose, pH, and water matrix were investigated. A synergetic coefficient of 3.84 was achieved for the combination of sodium percarbonate and ozone, confirming the effectiveness of this hybrid process. Scavenging tests revealed, that carbonate radicals, hydroxyl radicals, superoxide radicals, and singlet oxygen contributed to the degradation of bisphenol S. At the same operating condition, degradation effectiveness values of 99% and 81% were obtained by ozone combined with sodium percarbonate and hydrogen peroxide, respectively, demonstrating the superiority of sodium percarbonate over hydrogen peroxide in combination with ozone for the degradation of bisphenol S. Low concentration of inorganic anions had a negligible effect on the degradation, while carbonate ions increased the first-order degradation rate constant by 56%.

  • Degradation of cefadroxil drug by newly designed solar light responsive alcoholic template-based lanthanum ferrite nanoparticles
    • Ammara Nazir
    • Muhammad Imran
    • Farah Kanwal
    • Shoomaila Latif
    • Ayesha Javaid
    • Tak H. Kim
    • Grzegorz Boczkaj
    • Ashwag Shami
    • Hafiz M.N. Iqbal
    2023 ENVIRONMENTAL RESEARCH

    In this work, lanthanum ferrite nanoparticles were synthesized via a simple co-precipitation method. Two different templates, namely sorbitol and mannitol, were used in this synthesis to tune the optical, structural, morphological, and photocatalytic properties of lanthanum ferrite. The synthesized lanthanum ferrite-sorbitol (LFOCo-So) and lanthanum ferrite-mannitol (LFOCo-Mo) were investigated through Ultraviolet–Visible (UV–Vis), X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR), Raman, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), and photoluminescence (PL) techniques to study the effects of the templates on the tunable properties of lanthanum ferrite nanoparticles. The UV–Vis study revealed a remarkably small bandgap (2.09 eV) of LFOCo-So compared to the LFOCo-Mo having a band gap of 2.46 eV. XRD analysis revealed a single-phased structure of LFOCo-So, whereas LFOCo-Mo showed different phases. The calculated crystallite sizes of LFOCo-So and LFOCo-Mo were 22 nm and 39 nm, respectively. FTIR spectroscopy indicated the characteristics of metal-oxygen vibrations of perovskites in both lanthanum ferrite (LFO) nanoparticles, whereas a slight shifting of Raman scattering modes in LFOCo-Mo in contrast to LFOCo-So showed the octahedral distortion of the perovskite by changing the template. SEM micrographs indicated porous particles of lanthanum ferrite with LFOCo-So being more uniformly distributed, and EDX confirmed the stoichiometric ratios of the lanthanum, iron, and oxygen in the fabricated lanthanum ferrite. The high-intensity green emission in the photoluminescence spectrum of LFOCo-So indicated more prominent oxygen vacancies than LFOCo-Mo. The photocatalytic efficiency of synthesized LFOCo-So and LFOCo-Mo was investigated against cefadroxil drug under solar light irradiation. At optimized photocatalytic conditions, LFOCo-So showed higher degradation efficiency of 87% in only 20 min than LFOCo-Mo having photocatalytic activity of 81%. The excellent recyclability of the LFOCo-So reflected that it could be reused without affecting photocatalytic efficiency. These findings showed that sorbitol is a useful template for the lanthanum ferrite particles imparting outstanding features, enabling it to be used as an efficient photocatalyst for environmental remediation.

  • Degradation of Rhodamine dyes by Advanced Oxidation Processes (AOPs) – Focus on cavitation and photocatalysis - A critical review
    • Ashish V. Mohod
    • Malwina Momotko
    • Noor S. Shah
    • Mateusz Marchel
    • Mohammad Imran
    • Lingshuai Kong
    • Grzegorz Boczkaj
    2023 Full text Water Resources and Industry

    This review evaluates selected advanced oxidation processes (AOPs) - cavitation and photocatalysis - successfully used for wastewater treatment towards degradation of Rhodamine (Rh) dyes. Reactor configuration and impact of process parameters and oxidants addition (hydrogen peroxide, ozone, persulfates) on degradation effectiveness along with degradation mechanisms are discussed. Best technologies provide 100% degradation within 10–30 min. Rhodamine B is effectively degraded in highly acidic conditions (pH 2), while Rhodamine 6G requires basic conditions (pH 10). The most effective oxidants were hydrogen peroxide and ozone. Ecological Structure Activity Relationships (ECOSAR) revealed acute toxicities of the intermediates and by-products of the Rh dye.

  • Dehydrogenation in electron-induced dissociative ionization of pyridine molecule
    • Michał Jurkowski
    • Tomasz Wąsowicz
    2023 Romanian Journal of Physics

    The electron-impact dissociative ionization of pyridine has been investigated using mass spectrometry. Thirty-two well-resolved mass peaks have been identified in the cation mass spectra and assigned to the most likely ionic molecular fragments. The new sixteen ionic fragments' appearance energies have been determined, and sixteen others remeasured. The total cross-section for electron-impact ionization of pyridine has been measured at 100 eV. Thorough analysis indicates that at least three peaks' groups in the mass spectra occur via the shake-off dehydrogenation mechanism, i.e., by sequential hydrogen atoms elimination from the pyridine parent cation or its fragmentation products. The nature of this process is deciphered.

  • Dekodowanie kodów iterowanych z użyciem sieci neuronowej
    • Oskar Fiedot
    • Marek Blok
    2023 Full text Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Nadmiarowe kody iterowane są jedną z prostych metod pozyskiwania długich kodów korekcyjnych zapewniających dużą ochronę przed błędami. Jednocześnie, chociaż ich podstawowy iteracyjny dekoder jest prosty koncepcyjnie oraz łatwy w implementacji, to nie jest on rozwiązaniem optymalnym. Poszukując alternatywnych rozwiązań zaproponowano, przedstawioną w pracy, strukturę dekodera tego typu kodów wspomaganą przez sieci neuronowe. Zaproponowane rozwiązanie pozwala na wykrywanie oraz korekcję błędów w odbieranych ciągach.

  • DEM Analyses of Interface Behaviour Between Cohesionless Sand and Rigid Wall of Different Roughness
    • Aleksander Grabowski
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2023

    Artykuł dotyczy trójwymiarowych symulacji numerycznych quasi-statycznego ścinania między niespoistym piaskiem a sztywnymi ścianami w aparacie bezpośredniego ścinania ścian. Chropowatość ścian sztywnych wahała się od gładkiej do bardzo szorstkiej. Na górną ścianę działało stałe ciśnienie normalne. Symulacje numeryczne przeprowadzono metodą elementów dyskretnych (DEM). Ziarna piasku opisywano jako kulki z momentami kontaktowymi lub jako niesymetryczne nieregularne grudki. Zbadano wpływ chropowatości powierzchni na makroskopowe krzywe siła-przemieszczenie oraz na wyniki mikroskopowe na poziomie ziarna. Dla różnych chropowatości ścian obliczono wysokość strefy zlokalizowanej ścinania, rotacje ziaren oraz stosunek między poślizgami i rotacjami ziaren. Zaproponowano dwa różne warunki brzegowe wzdłuż ściany dla kontinuów mikropolarnych, biorąc pod uwagę rotacje i poślizgi ziaren oraz znormalizowaną chropowatość granicy faz. Wyniki DEM pozwalają lepiej zrozumieć zachowanie interfejsu między ciałami ziarnistymi a sztywnymi strukturami.

  • Dependent self-employed individuals: are they different from paid employees?
    • Ondřej Dvouletý
    • Dagmara Nikulin
    2023 Full text Employee Relations

    This study focuses on dependent self-employment, which covers a situation where a person works for the same employer as a typical worker while on a self-employment contractual basis, i.e., without a traditional employment contract and without certain rights granted to "regular" employees. The research exploits the individual-level dataset of 35 European countries extracted from the 2017 edition of the European Labour Force Survey and compares the characteristics of employees and dependent self-employed individuals. Methodologically, the study relies on the estimation of a multivariate logistic regression model. The main hypothesis assuming that dependent self-employed work most often in low-skilled occupations was empirically supported. There was also a non-linear (u-shaped) relationship between the years of accumulated experience (with a turning point at 35 years) and the likelihood of being dependent self-employed. Other results showed that dependent self-employed are less likely to be women, and they are more likely born outside of the countries where they participate in the labour markets. The study contributes to the field by adopting a comparable definition of dependent self-employment and exploiting the recent theoretical support of The Work Precarity Framework. The phenomenon should still be addressed by policymakers and labour office representatives, aiming to protect, primarily, vulnerable lower-skilled workers. The ongoing research should study the longitudinal dimension of dependent self-employment with a focus on motivational aspects.

  • Depolarisation Model for a BAN Indoor Scenario
    • Manuel M. Ferreira
    • Filipe D. Cardoso
    • Sławomir Ambroziak
    • Mariella Särestöniemi
    • Kenan Turbic
    • Luis M. Correia
    2023 Full text

    In this paper, an analysis of depolarisation in Body Area Networks for Body-to-Infrastructure communications based on a measurement campaign in the 5.8 GHz band in an indoor environment is performed. Measurements were made with an offbody antenna transmitting linearly polarised signals and dualpolarised receiving antennas carried by the user on the body. A Normal Distribution with a mean of 2.0 dB and a standard deviation of 4.3 dB is found to be the best fit for modelling crosspolarisation discrimination. The average correlation between the signals received by the orthogonally polarised antennas is below 0.5, showing that polarisation diversity can be used. A model is proposed for the average value of the standard deviation of the cross-polarisation discrimination ratio as a function of the transmitted polarisation, the mobility of users and link dynamics.

  • Der Begriff des Mythos bei Cassirer: zwischen UIdealismus, Ethnologie, politischer Philosophie und allgemeine Kulturphilosophie
    • Andrzej Karalus
    2023

    Der Mythos war eines der bevorzugten Forschungsobjekte Cassirers, denen er zwei Bücher, zahlreiche Artikel und wichtige längere Aufsätze widmete. In diesem Artikel versuche ich Cassirers Mythendeutung kurz zu rekapitulieren, um ihre Position in der Gesamtheit seines philosophischen Systems festzulegen und ihr Erklärungspotenzial zu gewinnen. In erstem Teil handle ich das allgemeine Problem des mythischen Denkens hauptsächlich aufgrund des zweiten Teils der Philosophie der symbolischen Formen ab. Ich möchte hierbei aufzeigen, dass der Mythos als symbolische Form einen Versuch der Vereinheitlichung der theoretischen Impulse des Deutschen Idealismus mit Feststellungen empirisch orientierter Kulturwissenschaften repräsentiert. Im zweiten Teil bespreche ich das Problem des Mythos aus Sicht der politischen Philosophie und im Hinblick auf die Totalitarismus-Debatte. In drittem Teil bespreche ich schließlich die Vorteile und Beschränkungen der Konzeption des totalitären Staates Cassirers und versuche seine Mythenauffassung in seine allgemeine Kulturphilosophie einzupflegen. Ich schlage vor, dass der Schlüssel zur fruchtbarsten Behandlung dieser Thematik vorerst in Das mythischen Denken zu finden ist, nicht in The Myth of the State. Ich weise auch auf die potentiellen Anwendungsbereiche seiner Betrachtungen hin.

  • Design advantages and analysis of a novel five-phase doubly-fed induction generator
    • Roland Ryndzionek
    • Michał Michna
    • Filip Kutt
    • Grzegorz Kostro
    • Krzysztof Blecharz
    2023 Full text COMPEL-THE INTERNATIONAL JOURNAL FOR COMPUTATION AND MATHEMATICS IN ELECTRICAL AND ELECTRONIC ENGINEERING

    Purpose – The purpose of this paper is to provide an analysis of the performance of a new five-phase doubly fed induction generator (DFIG). Design/methodology/approach – This paper presents the results of a research work related to fivephase DFIG framing, including the development of an analytical model, FEM analysis as well as the results of laboratory tests of the prototype. The proposed behavioral level analytical model is based on the winding function approach. The developed DFIG model was used at the design stage to simulate the generator’s no-load and load state. Then, the results of the FEM analysis were shown and compared with the results of laboratory tests of selected DFIG operating states. Findings – The paper provides the results of analytical and FEM simulation and measurement tests of the new five-phase dual-feed induction generator. The use of the MATLAB Simscape modeling language allows for easy and quick implementation of the model. Design assumptions and analytical model-based analysis have been verified using FEM analysis and measurements performed on the prototype. The results of the presented research validate the design process as well as show the fivephase winding design advantage over the three-phase solution regarding the control winding power quality. Research limitations/implications – The main disadvantage of the winding function approach-based model development is the simplification regarding omitting the tangential airgap flux density component. However, this fault only applies to large airgap machines and is insignificant in induction machines. The results of the DFIG analyses were limited to the basic operating states of the generator, i.e. the no-load state, the inductive and resistive load. Practical implications – The novel DFIG with five phase rotor control winding can operate as a regular three-phase machine in an electric power generation system and allows for improved control winding power quality of the proposed electrical energy generation system. This increase in power quality is due to the rotor control windings inverter-based PWM supply voltage, which operates with a wider per-phase supply voltage range than a three-phase system. This phenomenon was quantified using control winding current harmonic analysis.

  • Design and Evaluation of the Compact and Autonomous Energy Subsystem of a Wave Energy Converter
    • Marcin Drzewiecki
    • Jarosław Guziński
    2023 Full text ENERGIES

    This paper presents the results of the design process focused on the development of the energy subsystem (ES) of a wave energy converter (WEC). The ES is an important electrical part that significantly affects the energy reliability and energy efficiency of the entire WEC device. The designed ES was intended for compact WECs powering IoT network devices working in the distributed grid. The developed ES is an electronic circuit consisting of three cooperating subsystems used for energy conversion, energy storage, and energy management. The energy conversion subsystem was implemented as a set of single-phase bridge rectifiers. The energy storage subsystem was a battery-less implementation based on the capacitors. The energy management subsystem was implemented as a supervisory circuit and boost converter assembly. The designed ES was verified using the physical experiment method. The model experiment reflected the operation of the designed ES with a piezoelectric PZT-based WEC. The experimental results showed a 41.5% surplus of the energy supplied by ES over the energy demanded by the considered load at a duty cycle of ca. 6 min—37.2 mJ over 26.3 mJ, respectively. The obtained results have been evaluated and discussed. The results confirmed the designed ES as a convenient solution, which makes a significant contribution to the compact WECs that can be applied among others to a distributed grid of autonomous IoT network devices powered by free and renewable energy of sea waves. Finally, it will also enable sustainable development of mobile and wireless communication in those maritime areas where other forms of renewable energy may not be available.

  • Design and Optimization of a Compact Super-Wideband MIMO Antenna with High Isolation and Gain for 5G Applications
    • Bashar Esmail
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2023 Full text Electronics

    This paper presents a super-wideband multiple-input multiple-output (SWB MIMO) antenna with low profile, low mutual coupling, high gain and compact size for microwave and millimeter wave (mm-wave) fifth-generation (5G) applications. A single antenna is a simple elliptical-square shape with a small physical size of 20 × 20 × 0.787 mm3. The combination of both square and elliptical shapes results in an exceptionally broad impedance bandwidth spanning from 3.4 to 70 GHz. An-tenna dimensions are optimized using the trust-region algorithm to enhance its impedance band-width, and maintain the gain within a predefined limit across the entire band. For that purpose, regularized merit function is defined, which permits to control both the single antenna reflection response and gain. Subsequently, the SWB MIMO system is constructed with four radiators ar-ranged orthogonally. This arrangement results in high isolation, better than 20 dB, over a fre-quency band from 3.4 to 70 GHz band. Further, the system achieves an average gain of approxi-mately 7 dB below 45 GHz and a maximum gain equal to 12 dB for 70 GHz. The system exhibits excellent diversity performance throughout the entire bandwidth, as evidenced by the low enve-lope correlation coefficient (ECC) (<3∙10−3), total active reflection coefficient (TARC) (≤−10 dB), and channel capacity loss (CCL) (<0.3 bit/s/Hz) metrics, as well as high diversity gain (DG) of approxi-mately 10 dB. Experimental validation of the developed SWB MIMO demonstrates a good match-ing between the measurements and simulations.

  • Design and Optimization of Metamaterial-Based 5G Millimeter Wave Antenna for Gain Enhancement
    • Bashar Esmail
    • Sławomir Kozieł
    2023 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS

    In this brief, a low profile, broadband, high-gain antenna array based on optimized metamaterials (MMs) with dual-beam radiation is reported for 5G millimeters wave (mm-wave) applications. The design is a simple bow tie operating at a 5G band of 28 GHz. It consists of two bow ties with substrate integrated waveguide (SIW)-based power splitter. A broad impedance bandwidth of 26.3−29.8 GHz is obtained by appropriately combining the resonances of the bow ties and the SIW. Further, the antenna exhibits symmetrical dual-beam radiation at ±25˚ over a broad bandwidth in the end-fire direction due to the arrangement of the two radiators. A MM array has been etched in the same substrate shared with the antenna to improve the gain performance while preserving compact size. The trust-region (TR) gradient-based algorithm is used to optimize the structure dimensions and to achieve a maximum gain of 12.2 dB at 29 GHz. The developed MM-based antenna is validated experimentally with a good matching between the simulated and measured data. The system features a small size, low profile, high gain, broad bandwidth, and dual-beam in the E-plane, demonstrating its suitability for 5G mm-wave indoor scenarios.

  • Design and Preparation of Magnetically-Oriented Poly(styr-co-MMA)-3MPS Capped Fe(ZnO) Hybrid Microspheres for Ion Exchange Removal of Toxic Pollutants from Wastewater
    • Sahar Fatima
    • Muhammad Imran
    • Farah Kanwal
    • Ayesha Javaid
    • Shoomaila Latif
    • Grzegorz Boczkaj
    2023 Full text Water

    In this work, polymeric microspheres derived from polystyrene-co-methyl methacrylate embedded with magnetic ZnO nanoparticles (poly(styrene-co-MMA)-3MPS-Fe (ZnO)) were synthesized using the suspension polymerization method. The surfaces of polymeric Fe(ZnO) microspheres were improved by functionalization with amino and sulphonate groups. The physicochemical analysis indicated a large number of positively charged (anion exchange) groups (91 mmol/g) on the amine-modified polymeric microsphere (MFZPI) and a large number of negatively charged (cation exchange) groups (90 mmol/g) on the sulphonate-modified polymeric microsphere (SMFZPI)—revealing ambivalent character of obtained sorbent. The characterization of the synthesized compounds using various analytical techniques such as TGA, FTIR, XRD, SEM/EDX, UV-VIS and VSM indicated that synthesized microspheres were thermally stable, semi-crystalline in structure with hollow irregular morphology, optically active in UV region and slightly magnetic in nature. Due to the introduction of groups having ion exchange properties, these modified poly(styrene-co-MMA)-3MPS-Fe(ZnO) microspheres were used for the ion exchange sorptive removal of Cr(III) and fluorescein from aqueous matrix. The equilibrium sorption capacity of Cr(III) was 16.79 mg/g whereas of fluorescein was 12.03 mg/g under optimized conditions. Therefore, SMFZPI was found to be a promising sorbent for both cationic heavy metals and anionic dyes due to the presence of both acidic and basic groups. The mathematical modelling revealed that the sorption phenomenon followed pseudo-second-order kinetics with Freundlich equilibrium isotherm, indicating multilayer chemisorption of the pollutants on the synthesized ion exchange sorbents. This work establishes the utilization of polymeric magnetic ZnO-based ion exchange sorbents to effectively remove harmful toxins from wastewater.

  • Design and Synthesis of NTU-9/C3N4 Photocatalysts: Effects of NTU-9 Content and Composite Preparation Method
    • Damian Makowski
    • Wojciech Lisowski
    • Mateusz Baluk
    • Tomasz Klimczuk
    • Beata Bajorowicz
    • Mateusz Adam Baluk
    2023 Full text Materials

    Hybrid materials based on graphitic carbon nitride (g-C3N4) and NTU-9 metal–organic frameworks (MOF) were designed and prepared via solvothermal synthesis and calcination in air. The as-prepared photocatalysts were subsequently characterized using Brunauer–Emmett–Teller (BET) analysis, UV-Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) emission spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The obtained NTU-9/C3N4 composites showed a greatly improved photocatalytic performance for the degradation of toluene in the gas phase under LED visible-light irradiation (max = 415 nm). The physicochemical properties and photocatalytic activities of the obtained NTU- 9/C3N4 materials were tuned by varying the NTU-9 content (5–15 wt%) and preparation method of the composite materials. For composites prepared by calcination, the photocatalytic activity increased with decreasing NTU-9 content as a result of the formation of TiO2 from the MOFs. The best photocatalytic performance (65% of toluene was photodegraded after 60 min) was achieved by the NTU-9/C3N4 sample prepared via the solvothermal method and containing 15 wt% MOF, which can be attributed to the appropriate amount and stable combination of composite components, efficient charge separation, and enhanced visible-light absorption ability. The photocatalytic mechanisms of the prepared hybrid materials depending on the preparation method are also discussed.

  • Design and synthesis of TiO2/Ti3C2 composites for highly efficient photocatalytic removal of acetaminophen: The relationships between synthesis parameters, physicochemical properties, and photocatalytic activity
    • Anna Grzegórska
    • Agnieszka Gajewicz-Skrętna
    • Grzegorz Trykowski
    • Karol Sikora
    • Anna Zielińska-Jurek
    2023 Full text CATALYSIS TODAY

    In this study, we report the potential of TiO2/Ti3C2 composite fabricated by oxidation of MXene for degradation of persistent organic pollutants. The effect of the synthesis conditions (time, temperature, and reaction environment) on the morphology, physicochemical properties, and photocatalytic activity was investigated. It was found that acetaminophen degradation was positively correlated with TiO2 content in the composite structure. Furthermore, the findings confirmed that the synthesis reaction environment strongly influenced the obtained materials photocatalytic activity. The TiO2/Ti3C2 composite obtained by solvothermal route in the presence of hydrochloric acid and ammonium fluoride exhibited the highest efficiency towards acetaminophen degradation than other composite materials, for which ACT removal reached 92 % within 60 min of irradiation under simulated solar light. The improved photocatalytic performance can be attributed to the presence of anataserutile polymorphs exposing highly active { 0 0 1} and { 1 0 1} facets coupled with MXene. Superoxide anion radicals and hydroxyl radicals played a major role in ACT degradation. Moreover, 3-hydroxyacetaminophen was detected as the first intermediate of ACT degradation, leading quickly to aromatic ring opening and production of aliphatic acids. Overall, this work provides an effective strategy for designing novel and efficient MXene-based photocatalysts for the degradation of emerging contaminants in water systems.

  • Design of an Autonomous IoT Node Powered by a Perovskite-Based Wave Energy Converter
    • Marcin Drzewiecki
    • Jarosław Guziński
    2023 Full text Polish Maritime Research

    This paper presents the results of experimental research focused on wave energy harvesting and its conversion to power Internet of Things (IoT) devices. The harvesting and conversion process was performed using a wave energy converter (WEC) consisting of a lead zirconate titanate piezoelectric ceramic perovskite material and a prototype power electronic circuit. The designed WEC was considered as a power supply for an end node device (END) of an IoT network. The END consisted of a long-range radio module and an electronic paper display. A set of physical experiments were carried out, and the results confirmed that an energy surplus was supplied by WEC compared to the energy consumed by the END. Hence, the proposed scheme was experimentally validated as a convenient solution that could enable the autonomous operation of an IoT device. The use case presented here for the proposed WEC was analysed for selected sea areas on the basis of wave statistics. The novelty of this paper arises from an investigation that confirms that WECs can significantly contribute to the development of wireless and mobile IoT communication powered by freely available sea wave energy.

  • Design of compact self-quintuplexing antenna with high-isolation for penta-band applications
    • Rusan Kumar Barik
    • Sławomir Kozieł
    2023 Full text IEEE Access

    This article presents a novel compact self-quintuplexing antenna architecture based on a substrate-integrated rectangular cavity (SIRC) for pentaband applications. The proposed self-quintuplexing antenna is constructed by employing an SIRC, one Pi-shaped slot (PSS), one T-shaped slot (TSS), and five 50Ω microstrip feedlines. The PSS and TSS are engraved on the top of the SIRC to create five radiating patches, which are excited by five 50Ω feedlines to achieve pentaband operation with self-quintuplexing characteristics. The resonating frequencies can be tuned independently based on the dimension of the radiator without disturbing other bands. A detailed parametric analysis is carried out to provide a suitable frequency tunable range and high isolation. In addition, an equivalent lumped circuit is developed to analyze the proposed self-quintuplexing antenna. To validate the proposed antenna architecture, an SIRC-based self-quintuplexing antenna operating at 2.29, 2.98, 3.65, 4.37, and 5.08 GHz is fabricated and demonstrated. The fabricated antenna offers competitive performance with a compact size of 0.173λ2, pentaband operation, high isolation of 29.31 dB, and a wide frequency tunability range from 2.29 GHz to 6.03 GHz. Furthermore, the fabricated self-quintuplexing antenna exhibits the measured realized gain of 3.59, 4.55, 3.91, 5.70, and 4.92dBi at 2.29, 2.98, 3.64, 4.37, and 5.08 GHz, respectively.

  • Design of Frequency-Reconfigurable Branch-Line Crossover Using Rectangular Dielectric Channels
    • Rusan Kumar Barik
    • Sławomir Kozieł
    • Eirikur Bernhardsson
    2023 Full text IEEE Access

    This paper presents an efficient yet straightforward passive reconfiguration technique to tune the operating frequency of a branch-line crossover (BLCO). The underlying principle is to fill rectangular dielectric channels (RDCs) prepared beforehand with either air or materials of different relative permittivity. Two configurations (one RDC and three RDCs in each arm) of the branch-line crossover are employed to estimate the tunability range of the operating frequency. The introduction of RDCs packed with different materials in the branch lines modifies the effective permittivity of the dielectric medium, resulting in an alteration of the operating frequency. The size and the positions of the RDCs are optimized using full-wave electromagnetic simulations to achieve maximum tunability range while ensuring reasonable bandwidth. A lumped circuit model (LCM) is developed to analyze the working principle of the proposed technique. To validate computational models, two prototypes of the branch-line crossover are realized, fabricated, and experimentally demonstrated. The first BLCO packed with seven RDCs exhibits a frequency tuning range of 15.8%, whereas the second prototype filled with twenty-one RDCs features a tuning range of 36.9%.

  • Design of metamaterials: Preface
    • Anil Misra
    • François Hild
    • Victor Eremeev
    2023 MECHANICS RESEARCH COMMUNICATIONS

    This special issue “Design of metamaterials” collects several papers that have presented theoretical, numerical, and experimental studies of metamaterials.

  • Design of novel highly sensitive sensors for crack detection in metal surfaces: theoretical foundation and experimental validation
    • Zahra Shaterian
    • Ali Karami Horestani
    • Ferran Martin
    • Michał Mrozowski
    2023 Full text Scientific Reports

    The application of different types of microwave resonators for sensing cracks in metallic structures has been subject of many studies. While most studies have been focused on improving the sensitivity of planar crack sensors, the theoretical foundation of the topic has not been treated in much detail. The major objective of this study is to perform an exhaustive study of the principles and theoretical foundations for crack sensing based on planar microwave resonators, especially defective ground structures (DGS) including complementary split ring resonators (CSRRs). The analysis is carried out from the equivalent circuit model as well as the electromagnetic (EM) field perspectives, and guidelines for the design of crack sensors with high sensitivity are developed. Numerical and experimental validation of the provided theoretical analysis is another aim of this article. With this aim, the developed guidelines are used to design a crack sensor based on a single-ring CSRR. It is shown that the sensitivity of the proposed sensor is almost three times higher than the sensitivity of a conventional double-ring CSRR. Moreover, it is demonstrated that folded dumbbell-shape DGS resonators can be used to achieve even higher sensitivities. The CSRR-based crack sensors presented in this study and other studies available in the literature are only sensitive to cracks with a specific orientation. To address this limitation, a modified version of the DGS is proposed to sense cracks with arbitrary orientations at the cost of lower sensitivity. The performance of all the presented sensors is validated through EM simulation, equivalent circuit model extraction, and measurement of the fabricated prototypes.

  • Designing efficient A-D-A1-D-A type fullerene free acceptor molecules with enhanced power conversion efficiency for solar cell applications
    • Malik Muhammad Iqbal Asif
    • Muhammad Arshad
    • Muhammad Yasir Mehboob
    • Muhammad Khan
    • Sanwal Piracha
    2023 SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

    The achievement of highly efficient power conversion efficiency (PCE) is a big concern for non-fullerene organic solar cells (NF-OSCs) because PCE can depend on numerous variables. Here, new five novel acceptor molecules without fullerenes were developed and investigated using DFT (density functional theory) and TD-DFT (time dependent-density functional theory). Compared to the recently synthesized molecule (PZ-dIDTC6), the developed molecules display a narrow optical band gap, exhibiting a red shift in the absorption spectrum. The developed molecules (YM1-YM5) express high mobility of electrons and holes in the active layer of OSCs (organic solar cells). In addition, high open-circuit voltage (Voc) values with maximum charge density shifting are noted in designed molecules. YM1-YM5 is also associated with low binding energy and excitation energy. This work proves that noncovalent conformational locking is favourable for improving PCE devices.

  • Detecting Lombard Speech Using Deep Learning Approach
    • Krzysztof Kąkol
    • Grazina Korvel
    • Gintautas Tamulevicius
    • Bożena Kostek
    2023 Full text SENSORS

    Robust Lombard speech-in-noise detecting is challenging. This study proposes a strategy to detect Lombard speech using a machine learning approach for applications such as public address systems that work in near real time. The paper starts with the background concerning the Lombard effect. Then, assumptions of the work performed for Lombard speech detection are outlined. The framework proposed combines convolutional neural networks (CNNs) and various two-dimensional (2D) speech signal representations. To reduce the computational cost and not resign from the 2D representation-based approach, a strategy for threshold-based averaging of the Lombard effect detection results is introduced. The pseudocode of the averaging process is also included. A series of experiments are performed to determine the most effective network structure and the 2D speech signal representation. Investigations are carried out on German and Polish recordings containing Lombard speech. All 2D signal speech representations are tested with and without augmentation. Augmentation means using the alpha channel to store additional data: gender of the speaker, F0 frequency, and first two MFCCs. The experimental results show that Lombard and neutral speech recordings can clearly be discerned, which is done with high detection accuracy. It is also demonstrated that the proposed speech detection process is capable of working in near real-time. These are the key contributions of this work.

  • Detecting type of hearing loss with different AI classification methods: a performance review
    • Michał Kassjański
    • Marcin Kulawiak
    • Tomasz Przewoźny
    • Dmitry Tretiakow
    • Jagoda Kuryłowicz
    • Andrzej Molisz
    • Krzysztof Koźmiński
    • Aleksandra Kwaśniewska
    • Paulina Mierzwińska-Dolny
    • Miłosz Grono
    2023

    Hearing is one of the most crucial senses for all humans. It allows people to hear and connect with the environment, the people they can meet and the knowledge they need to live their lives to the fullest. Hearing loss can have a detrimental impact on a person's quality of life in a variety of ways, ranging from fewer educational and job opportunities due to impaired communication to social withdrawal in severe situations. Early diagnosis and treatment can prevent most hearing loss. Pure tone audiometry, which measures air and bone conduction hearing thresholds at various frequencies, is widely used to assess hearing loss. A shortage of audiologists might delay diagnosis since they must analyze an audiogram, a graphic representation of pure tone audiometry test results, to determine hearing loss type and treatment. In the presented work, several AI-based models were used to classify audiograms into three types of hearing loss: mixed, conductive, and sensorineural. These models included Logistic Regression, Support Vector Machines, Stochastic Gradient Descent, Decision Trees, RandomForest, Feedforward Neural Network (FNN), Convolutional Neural Network (CNN), Graph Neural Network (GNN), and Recurrent Neural Network (RNN). The models were trained using 4007 audiograms classified by experienced audiologists. The RNN architecture achieved the best classification performance, with an out-of-training accuracy of 94.46\%. Further research will focus on increasing the dataset and enhancing the accuracy of RNN models.

  • Detection of Toxoplasma gondii Infection in Small Ruminants: Old Problems, and Current Solutions
    • Lucyna Holec-Gąsior
    • Karolina Sołowińska
    2023 Full text Animals

    Toxoplasmosis is a parasitic zoonosis of veterinary importance, with implications for public health. Toxoplasma gondii infection causes abortion or congenital disease in small ruminants. Moreover, the consumption of infected meat, cured meat products, or unpasteurized milk and dairy products can facilitate zoonotic transmission. Serological studies conducted in various European countries have shown the high seroprevalence of specific anti-T. gondii antibodies in sheep and goats related to the presence of oocysts in the environment, as well as climatic conditions. This article presents the current status of the detection possibilities for T. gondii infection in small ruminants and their milk. Serological testing is considered the most practical method for diagnosing toxoplasmosis; therefore, many studies have shown that recombinant antigens as single proteins, mixtures of various antigens, or chimeric proteins can be successfully used as an alternative to Toxoplasma lysate antigens (TLA). Several assays based on DNA amplification have been developed as alternative diagnostic methods, which are especially useful when serodiagnosis is not possible, e.g., the detection of intrauterine T. gondii infection when the fetus is not immunocompetent. These techniques employ multicopy sequences highly conserved among different strains of T. gondii in conventional, nested, competitive, and quantitative reverse transcriptase-PCR.

  • Detection of Water on Road Surface with Acoustic Vector Sensor
    • Józef Kotus
    • Grzegorz Szwoch
    2023 Full text SENSORS

    This paper presents a new approach to detecting the presence of water on a road surface, employing an acoustic vector sensor. The proposed method is based on sound intensity analysis in the frequency domain. Acoustic events, representing road vehicles, are detected in the sound intensity signals. The direction of the incoming sound is calculated for the individual spectral components of the intensity signal, and the components not originating from the observed road section are discarded. Next, an estimate of the road surface state is calculated from the sound intensity spectrum, and the wet surface detection is performed by comparing the estimate with a threshold. The proposed method was evaluated using sound recordings made in a real-world scenario, and the algorithm results were compared with data from a reference device. The proposed algorithm achieved 89% precision, recall and F1 score, and it outperforms the traditional approach based on sound pressure analysis. The test results confirm that the proposed method may be used for the detection of water on the road surface with acoustic sensors as an element of a smart city monitoring system.

  • Determinants of the incidence of non-academic staff in European and US HEIs
    • Alessandro Avenali
    • Cinzia Daraio
    • Joanna Wolszczak-Derlacz
    2023 Full text HIGHER EDUCATION

    In this article, we contribute to the scant literature covering quantitative studies on the determinants of the non-academic staff incidence in higher education institutions by analysing how the proportion of non-academic staff is related to key features such as size, prestige, year of foundation and financial structure of universities. We apply nonlinear regression analysis to compare HEIs across Europe and the USA, taking into account time and cross-country heterogeneity of the two balanced panel datasets concerning European and American universities over a period of 6 years (2011–2016 for Europe and 2012–2017 for the USA). Evidence suggests that in both Europe and the USA, public and larger (if sufficiently large) as well as more research-oriented units are characterised by a higher proportion of non-academic staff. In Europe, we observe an inverted U-shaped effect of the share of non-personnel expenditure and the foundation year on the proportion of nonacademic staff, while the proportion of non-academic staff decreases with the share of core and third-party funding. For the USA, we obtain similar findings except that the share of core funding and third-party funding is characterised by a U-shaped effect, and the impact of the share of non-personnel expenditure has no empirical effect on the proportion of nonacademic staff. Additionally, we discover that some factors that contribute to the proportion of non-academic staff may constitute indicators of performance, suggesting the need for further research to extend our knowledge on the complex issue of the role played by non-academic staff in university performance.

  • Determinanty stabilności fiskalnej jednostki samorządu terytorialnego
    • Maria Jastrzębska
    2023

    Celem rozdziału jest omówienie istoty i znaczenia stabilności fiskalnej JST oraz dokonanie klasyfikacji jej determinant w podziale na instytucjonalno- -prawne, ekonomiczno-finansowe, społeczne i naturalne, polityczne i organizacyjne, a także zwrócenie uwagi na te z nich, które szczególnie negatywnie oddziałują na stabilność fiskalną JST (w podziale na niezależne i zależne od JST).

  • Determinanty stabilności fiskalnej jednostki samorządu terytorialnego
    • Maria Jastrzębska
    2023 Full text FINANSE Czasopismo Komitetu Nauk o Finansach PAN

    . Celem rozdziału jest omówienie istoty i znaczenia stabilności fiskalnej JST oraz dokonanie klasyfikacji jej determinant w podziale na instytucjonalno- -prawne, ekonomiczno-finansowe, społeczne i naturalne, polityczne i organizacyjne, a także zwrócenie uwagi na te z nich, które szczególnie negatywnie oddziałują na stabilność fiskalną JST (w podziale na niezależne i zależne od JST)

  • Determination of benzodiazepines and Z-hypnotic drugs in whole blood samples by GC–MS/MS: Method development, validation and application
    • Laura Banaszkiewicz
    • Mateusz Kacper Woźniak
    • Michal Kaliszan
    • Agata Kot-Wasik
    2023 MICROCHEMICAL JOURNAL

    Benzodiazepines (BZDs) and Z-drugs are widely used as anxiolytics, sedative hypnotics, anticonvulsants and muscle relaxants. “Designer benzodiazepines” (DBZDs) are a new psychoactive substance class consisting of benzodiazepine derivatives that are not allowed for medical use and are known for being used recreationally. From a toxicologist standpoint, the huge number of such substances implicate a necessity for developing fast and reliable methods to identify and quantify these substances in biological matrices, especially in blood. In this study, a method based on gas chromatography–tandem mass spectrometry (GC–MS/MS) was developed and validated for the determination of 28 benzodiazepine derivatives and 3 Z- drugs. Liquid–liquid extraction requiring the use of a 0.5 mL sample of whole blood and 1 mL of ethyl acetate was applied. No derivatization was necessary to obtain sensitivity and selectivity. All validation data met the established acceptance criteria in accordance with international forensic toxicology guidelines. The method was linear within the tested range of 1–100 ng/mL, 1–200 ng/mL, 1–250 ng/mL, 5–200 ng/mL and 10–250 ng/mL depending on the analyte. The LOD was in the range of 0.09 to 0.66 ng/mL, while the LOQ was between 1 and 10 ng/mL. The calculated mean accuracy ranged between 85.1% and 114.4% for intraday replicates and between 85.2% and 111.2% for interday replicates. Intraday precision (as CVs) ranged from 0.2% to 12.5%, while interday precision ranged from 2.0% to 14.5%. Recovery was between 83.8% and 111.2%. This study was the first attempt to apply GC–MS/MS for the multianalyte determination of benzodiazepines and Z-drugs without analyte derivatization. The developed method proved to be sensitive, specific, simple and fast. The analysis in MRM mode gives high sensitivity and selectivity. Thus, the presented method can be successfully utilized for clinical and forensic toxicology analysis, for interpretation of results and for the preparation of forensic toxicological opinions for courts of law.

  • Determination of equivalent axle load factors with the use of strain energy of distortion
    • Dawid Ryś
    • Francesco Canestrari
    2023 Full text Road Materials and Pavement Design

    The paper proposes a new method for calculation of equivalent axle load factors based on the analysis of strain energy of distortion induced in road pavements by traffic loads. The main advantage of the method is the more accurate calculation of the effects of multiple axles and super single versus dual tyres. The methodconsiders the location of critical points, at which strain energy of distortion reaches extreme values. When single axles are considered, the function of equivalent axle load factor takes on the form of the well-known power equation with the exponent ranging from 2.7 to 5.3. It was proved that the damaging effect of triple axles on asphalt pavement is several times higher than the damaging effect of three single axles carrying the same load, but at a greater distance to each other. Due to this fact, traffic load may be significantly underestimated in many pavement design methods.

  • Determination of Glycerol, Propylene Glycol, and Nicotine as the Main Components in Refill Liquids for Electronic Cigarettes
    • Paweł Kubica
    2023 Full text MOLECULES

    Refill liquids for electronic cigarettes are an important area of research due to the health safety and quality control of such products. A method was developed for the determination of glycerol, propylene glycol, and nicotine in refill liquids using liquid chromatography, coupled with tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring (MRM) mode with electrospray ionisation (ESI). Sample preparation was based on a simple dilute-and-shoot approach, with recoveries ranging from 96 to 112% with coefficients of variation < 6.4%. Linearity, limits of detection and quantification (LOD, LOQ), repeatability, and accuracy were determined for the proposed method. The proposed sample preparation and the developed chromatographic method using hydrophilic interaction liquid chromatography (HILIC) were successfully applied for the determination of glycerol, propylene glycol, and nicotine in refill liquid samples. For the first time, the developed method using HILIC-MS/MS has been applied for the determination of the main components of refill liquids in a single analysis. The proposed procedure is rapid and straightforward and is suitable for quick determination of glycerol, propylene glycol, and nicotine. The nicotine concentrations corresponded to the labelling of samples (it varied from <LOD—11.24 mg/mL), and the ratios of propylene glycol to glycerol were also determined.

  • Determination of Liquid Detergent Pods as a Potential Microplastic Source
    • Karolina Gwizdała
    • Paweł Szarlej
    • Przemysław Gnatowski
    • Edyta Piłat
    • Maciej Sienkiewicz
    • Justyna Kucińska-Lipka
    2023 Full text Chemistry & Chemical Technology

    Washing pods became a popular way to add detergent to washing machines. Despite the claims about the degradability of the pod film, the sludge in pipes can be observed after the usage of such pods. This study focused on a quantitative and qualitative analysis of washing pod films as a source of microplastic.

  • Determination of t8/5 cooling times for underwater local dry welding of steel
    • Grzegorz Rogalski
    • Aleksandra Świerczyńska
    • Dariusz Fydrych
    2023 MARINE STRUCTURES

    Knowledge of thermal history is the basic condition for studying the structure - properties of welded joints. The determinant of thermal history is the thermal cycle, whose in-situ measurements are still a big challenge. Water as the welding environment complicates this issue even more. The article presents a method to determine an equation for calculating t8/5 cooling times for underwater gas metal arc welding of unalloyed steels using the local dry cavity method. The work uses the contact method of temperature measurements with the use of thermocouples to obtain the temperature changes of the points of welded joints covered by the thermal field. On this basis, the values of the t8/5 cooling times were determined. A regression analysis of the Response Surface Method was used to determine the equation, which resulted in a second-order model with interactions. Statistically significant factors were determined (thickness of welded elements and heat input value) and the model veracity was confirmed as the assumptions of normality and homogeneity of variance (homoscedasticity) of the residuals were met. The t8/5 cooling time values depend on the thickness of the welded elements and heat input value in a nonlinear way. In terms of the test conditions, the cooling times ranged from 3.0 to 7.7 s. The equation allowed for the calculation of t8/5 cooling times during underwater welding of unalloyed steels using the local dry cavity method based on the variability of the experimental conditions with satisfactory accuracy.

  • Determination of the Major By-Products of Citrus hystrix Peel and Their Characteristics in the Context of Utilization in the Industry
    • Martyna Lubinska-Szczygeł
    • Anna Kuczyńska-Łażewska
    • Małgorzata Rutkowska
    • Żaneta Polkowska
    • Elena Katrich
    • Shela Gorinstein
    2023 Full text MOLECULES

    Kaffir lime (Citrus hystrix) is a popular citrus in Southeast Asia. Despite the growing interest in the peel of the fruit, the leaves are the most frequently used part of the fruit. The aim of the study was to determine the main by-products of the peel, such as pectins, minerals, essential oil, and bioactive compounds, and to evaluate the possibility of using them in various branches of industry. In the study of the essential oil obtained by hydrodistillation performed using the TGA chromatography technique (GC-MS), sabinene (31.93%), β-pinene (26%), and limonene (19%) were selected as the most abundant volatile compounds. Nine microelements (Fe, Zn, Cu, Mn, Co, Ni, Cr, Mo, and V), four macroelements (Mg, Ca, K, and Na), and seven ballast substances (Cd, Hg, Pb, Al, V, Sr, and Pt) were also determined using the microwave plasma-atomic emission spectrometry technique (MP-AES). In the case of microelements, iron 32.72 ± 0.39 mg/kg DW (dry weight) had the highest concentration. In the case of macroelements, the calcium content was 9416 ± 34 mg/kg DW. Optimization of the pectin extraction was also performed by selecting citric acid and obtaining a yield of 7.6–17.6% for acid extraction and 9.9–28.2% for ultrasound-assisted extraction (UAE), depending on the temperature used. The obtained pectins were characterized by the degree of methylation, galacturonic acid content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, and DSC (differential scanning calorimetry) analysis. Among bioactive compounds, the contents of polyphenols (22.63 ± 2.12 mg GAE/g DW), flavonoids (2.72 ± 0.25 mg CE/g DW, vitamin C (2.43 ± 0.19 mg Asc), xantoproteins + carotenes (53.8 ± 4.24 ug), anthocyanins (24.8 ± 1.8 mg CGE/kg DW), and chlorophylls A and B (188.5 ± 8.1, 60.4 ± 3.23 µg/g DW) were evaluated. Antioxidant capacity using (cupric ion-reducing antioxidant capacity) CUPRAC and DPPH assays was also provided with the results of 76.98 ± 8.1, and 12.01 ± 1.02 µmol TE/g DW, respectively.

  • Developing Materials for Biodegradable Otolaryngological Stents
    • Marta Razimowicz
    • Przemysław Gnatowski
    • Paweł Szarlej
    • Edyta Piłat
    • Maciej Sienkiewicz
    • Justyna Kucińska-Lipka
    2023 Full text Chemistry & Chemical Technology

    Materials for otolaryngological stents have to be characterized by good tensile strength, wear resistance, biocompatibility, and specific degradation time. This work aimed to synthesize polyurethanes based on various biodegradable polyol blends. Their biodegradability and mechanical properties were tested and compared to commercial BIOFLEX material.

  • Development and application of asphalt binder relaxation test in different dynamic shear rheometers
    • Johannes Büchner
    • Dawid Ryś
    • Stefan Trifunović
    • Michael P. Wistuba
    2023 CONSTRUCTION AND BUILDING MATERIALS

    In this study, a novel relaxation test is proposed to evaluate asphalt binder low temperature properties using a Dynamic Shear Rheometer (DSR) with parallel plates of 4 mm in diameter. Three rheometers from three different manufacturers are used to analyze seven asphalt binders. Different material parameters are derived which are useful to evaluate and discriminate different asphalt binders. Test results of all three instruments from different manufacturers are judged identical. Finally, results are compared to results from low temperature tests using a Bending Beam Rheometer (BBR) and a linear correlation is identified for the characteristic m-value from BBR testing.

  • Development and evaluation of RADA-PDGF2 self-assembling peptide hydrogel for enhanced skin wound healing
    • Milena Deptula
    • Joanna Sawicka
    • Piotr Sass
    • Paweł Sosnowski
    • Przemyslaw Karpowicz
    • Małgorzata Zawrzykraj
    • Anna Wardowska
    • Anna Tymińska
    • Maria Dzierżyńska
    • Zuzanna Pietralik-Molińska
    • Barbara Peplińska
    • Jacek Zielinski
    • Karolina Kondej
    • Maciej Kozak
    • Paweł Sachadyn
    • S. Rodziewicz-Motowidło
    • Michal Pikula
    2023 Full text Frontiers in Pharmacology

    Background: Wound healing complications affect numerous patients each year, creating significant economic and medical challenges. Currently, available methods are not fully effective in the treatment of chronic or complicated wounds; thus, new methods are constantly sought. Our previous studies showed that a peptide designated as PDGF2 derived from PDGF-BB could be a promising drug candidate for wound treatment and that RADA16-I can serve as a release system for bioactive peptides in wound healing. Based on that, in this work, we designed a new self-assembling hydrogel RADA-PDGF2, connecting both peptides by a sequence specific for neutrophil elastase, and evaluated its activity in wound healing. Methods: The physicochemical properties of the designed scaffold were analyzed using transmission electron microscopy, atomic force microscopy, cryoSEM microscopies, and circular dichroism spectroscopy. The enzymatic cleavage was performed using human neutrophil elastase and monitored using high performance liquid chromatography and MS spectroscopic techniques. The aforementioned techniques (HPLC and MS) were also used to assess the stability of the peptide in water and human plasma. The biological activity was analyzed on human skin cells using a colorimetric XTT test, collagen synthesis evaluation, and a migration assay. The biocompatibility was analyzed with LDH cytotoxicity assay and flow cytometric analysis of activation of immune cells. Finally, RADA-PDGF2 activity in wound healing was checked in a mouse dorsal skin injury model. Results: The analysis showed that RADA-PDGF2 can self-assemble, form a hydrogel, and release a bioactive sequence when incubated with human elastase. It shows pro-proliferative and pro-migratory properties and accelerates wound closure in the mouse model compared to RADA16-I. In addition, it is not cytotoxic to human cells and does not show immunogenicity. RADA-PDGF2 seems to be a promising drug candidate for wound management.