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Gdańsk University of Technology

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Publications from the year 2025

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  • Polymer-Enhanced Active Layer Crystallization in Low-Temperature Carbon-Based Perovskite Solar Cells
    • Shih-Han Huang
    • Yu-Hsiang Chen
    • Hou-Chin Cha
    • Damian Głowienka
    • Ming-Chung Wu
    • Yu-Ching Huang
    2025 ENERGY & FUELS

    High-efficiency perovskite solar cells (PSCs) are emerging as a promising next-generation, low-cost, photovoltaic technology. A key advantage of PSCs is their compatibility with diverse manufacturing techniques, enabling the pursuit of low-cost, stable PSCs. Carbon electrodes, known for their scalability, chemical inertness, and ease of processing through screen printing, have recently seen the development of low-temperature carbon electrodes with high conductivity for use in PSCs. However, optimizing low-temperature carbon-based PSCs (LTC-PSCs), particularly improving the interface between the perovskite and carbon electrodes, remains a significant challenge. In this study, poly(3-hexylthiophene-2,5-diyl) (P3HT) was employed as an additive and a hole-transporting layer (HTL) in LTC-PSCs with low-temperature screen-printing carbon electrodes. The incorporation of P3HT in antisolvent improved the perovskite/carbon interface, reducing the defect density of the perovskite layer. This resulted in a significant average power conversion efficiency (PCE) improvement of 11%. The LTC-PSCs achieved a PCE of 10.90% and demonstrated exceptional stability, retaining 90% of initial PCE after 1200 h under ambient air. This research highlights the potential of LTC-PSCs as low-cost strategies for the commercialization of PSCs.

  • Pomiary termowizyjne temperatury w operacjach maszynowego docierania powierzchni płaskich
    • Adam Barylski
    2025 Dozór Techniczny

    W artykule przedstawiono problematykę oraz wyniki badań nagrzewania się elementów układu obróbkowego docierarki jednotarczowej do płaszczyzn o standardowej kinematyce. Badano wpływ podstawowych warunków obróbki na temperaturę docieranych materiałów oraz zmiany temperatury głównych elementów obrabiarki. W badaniach wykorzystano kamerę termowizyjną. Wyniki pomiarów mogą być przydatne m.in. do określenia przerw między cyklami obróbki poszczególnych partii elementów, w przypadku kiedy w konstrukcji docierarki nie występuje wymuszone wodne chłodzenie tarczy docierającej. W artykule przedstawiono problematykę oraz wyniki badań nagrzewania się elementów układu obróbkowego docierarki jednotarczowej do płaszczyzn o standardowej kinematyce. Badano wpływ podstawowych warunków obróbki na temperaturę docieranych materiałów oraz zmiany temperatury głównych elementów obrabiarki. W badaniach wykorzystano kamerę termowizyjną. Wyniki pomiarów mogą być przydatne m.in. do określenia przerw między cyklami obróbki poszczególnych partii elementów, w przypadku kiedy w konstrukcji docierarki nie występuje wymuszone wodne chłodzenie tarczy docierającej. W artykule przedstawiono problematykę oraz wyniki badań nagrzewania się elementów układu obróbkowego docierarki jednotarczowej do płaszczyzn o standardowej kinematyce. Badano wpływ podstawowych warunków obróbki na temperaturę docieranych materiałów oraz zmiany temperatury głównych elementów obrabiarki. W badaniach wykorzystano kamerę termowizyjną. Wyniki pomiarów mogą być przydatne m.in. do określenia przerw między cyklami obróbki poszczególnych partii elementów, w przypadku kiedy w konstrukcji docierarki nie występuje wymuszone wodne chłodzenie tarczy docierającej. W artykule przedstawiono problematykę oraz wyniki badań nagrzewania się elementów układu obróbkowego docierarki jednotarczowej do płaszczyzn o standardowej kinematyce. Badano wpływ podstawowych warunków obróbki na temperaturę docieranych materiałów oraz zmiany temperatury głównych elementów obrabiarki. W badaniach wykorzystano kamerę termowizyjną. Wyniki pomiarów mogą być przydatne m.in. do określenia przerw między cyklami obróbki poszczególnych partii elementów, w przypadku kiedy w konstrukcji docierarki nie występuje wymuszone wodne chłodzenie tarczy docierającej.

  • Porous Deep Eutectic Solvents–Unfulfilled Dream or the Next Breakthrough in Scientific Innovation?
    • Marcin Wysokowski
    • Patrycja Makoś-Chełstowska
    • Alina Brzęczek‐Szafran
    • Aleksandra Sikora
    • Adam Gorczyński
    • Teofil Jesionowski
    2025 Advanced Science

    Porous deep eutectic solvents (PDES) are capturing the imagination of scientists, promising a revolutionary leap in material science. These innovative materials, blending the versatility of deep eutectic solvents (DES) with the intricate architectures of porous structures, offer an exciting array of applications—from green chemistry and catalysis to energy storage and environmental remediation. However, the journey from laboratory curiosity to industrial application is fraught with challenges. This perspective article analyzes the realm of PDES, scrutinizing the cutting-edge advancements and the challenges that lie ahead. By exploring their synthesis, unique properties, and diverse application potential, the critical question is asked: are PDES an unfulfilled dream or the next big breakthrough in scientific innovation? A comprehensive analysis reveals a “landscape” ripe with opportunity, suggesting that with targeted research and development, PDES can indeed become a cornerstone technology, driving progress across multiple scientific domains.

  • Power Transmission for Millimeter-Wave Indoor/Outdoor Wearable IoT Devices Using Grounded Coplanar Waveguide-Fed On-Body Antenna
    • Fuad Erman
    • Sławomir Kozieł
    • Alhareth Zyoud
    • Leifur Leifsson
    • Ullah Ubaid
    • Shaker Alkaraki
    2025 Full text IEEE Access

    This paper presents for the first-time evaluation of wireless power transmission (WPT) for sustainable low-powered Internet of Things (IoT) devices in realistic indoor/outdoor scenarios using empirical propagation models at 28 GHz. The used empirical propagation models have shown that using an on-body 9×9 mm-wave rectenna array based on a proposed mm-wave antenna is able to charge IoT devices at a distance of 57 m for line-of-sight (LOS) indoor temporal environment, and at a distance of 10 m for LOS outdoor tropical propagation model using a base station with 53 dBm transmission power. Furthermore, the mm-wave on-body 9×9 rectenna array occupies an area equal to that of a single UHF rectenna, while collecting 17-fold more power. In addition, the article discusses the design and experimental results of a single-element on-body mm-wave antenna used to design the 9×9 rectenna array. The proposed mm-wave antenna is a single-layer low-profile structure. Furthermore, the antenna has a stable gain of over 9.5 dBi and a wide beamwidth. The on-body antenna structure consists of rectangular multi-slot patch fed by a 50 Ω grounded coplanar waveguide (GCPW) line. Employing the multi-slot configuration results in a wearable antenna’s impedance bandwidth of 3.73 GHz. The peak measured gain of the antenna is 10.5 for chest/arm-mounted case in the operating 28 GHz N257 5G band. The antenna’s radiation pattern forms a wide off-body forward direction beam. A prototype of the proposed antenna is fabricated and validated experimentally for both cases on a human volunteer arm/chest and in the free space. The size of the proposed structure is small and can collect power with high efficiency due to the short wavelength of millimeter wave (mm-wave) in contrast to UHF antennas.

  • Predicting a passenger ship's response during evasive maneuvers using Bayesian Learning
    • Mateusz Gil
    • Jakub Montewka
    • Przemysław Krata
    2025 Full text RELIABILITY ENGINEERING & SYSTEM SAFETY

    The rapidly advancing automation of the maritime industry – for instance, through onboard Decision Support Systems (DSS) – can facilitate the introduction of advanced solutions supporting the process of collision avoidance at sea. Nevertheless, relevant solutions that aim to correctly predict a ship's behavior in irregular waves are only available to a limited extent by omitting the impact of wave stochastics on resulting evasive maneuvers. This is mainly due to the complexity of the phenomena, the existing couplings therein, and the time inefficacy in resolving the problem through real-time simulations. Therefore, this paper attempts to fill this knowledge gap by presenting a probabilistic, data-driven meta-model trained using an extensive set of 6DOF numerical simulations of vessel motions in irregular waves. For this purpose, machine learning adopting causal probabilistic modeling with Bayesian Belief Network (BBN) was employed. The latter offers two-way reasoning in the presence of uncertainty and provides insight into the meta-model's outcome. This, in turn, helps estimate a set of safety-critical parameters for a large passenger ship performing an evasive maneuver. This set comprises a huge quantity of ship turning circle parameters as well as the hull's rotational motions and resulting lateral accelerations, all simulated multiple times to consider the stochastic realization of the waves. The proposed meta-model can be used to assist watchkeeping officers’ decisions or raise their awareness concerning the possible consequences of evasive maneuvers performed. The achieved accuracy of the meta-model's prediction lies within a range from 81% to 98%, which makes it suitable for this purpose.

  • Predicting creep failure life in adhesive-bonded single-lap joints using machine learning
    • Faizullah Jan
    • Marcin Kujawa
    • Piotr Paczos
    • Victor Eremeyev
    2025 Full text Scientific Reports

    Accurately predicting the creep failure life of adhesive joints, particularly single-lap adhesive joints (SLAJs), remains still a significant challenge, requiring substantial time and resources and the ability to predict the duration of creep failure in SLAJs is critical to ensuring structural integrity and reducing the failure of creep-prone adhesive joints. In this study, machine learning (ML) was used to identify the critical features that ultimately influence the durability of SLAJs due to creep. These key features were determined through correlation analysis and sequential feature selection. Multiple ML algorithms were employed to analyze complex relationships among key features and predict creep failure life. Finally, the results of the analysis highlight the importance of features such as SLAJ creep strain, adhesive tensile strength (UTS), SLAJ creep stress, adhesive surface area (A), and Young’s modulus (E). Of the ML models tested, the random forest (RF) model was the most effective in predicting creep failure life. Moreover, the accuracy of the predictions made by the proposed ML model, using original code written in Python, has been verified in experimental tests. All datasets generated and analyzed during the current study, along with the code, are available in the repository accompanying the paper.

  • Probiotic potential of Bacillus Isolates from Polish Bee Pollen and Bee Bread
    • Karolina Pełka
    • Ahmer Hafeez
    • Randy Worobo
    • Piotr Szweda
    2025 Full text Probiotics and Antimicrobial Proteins

    The main goal of this study was the evaluation of the probiotic potential of 10 Bacillus spp. strains isolated from 5 bee bread and 3 bee pollen samples. The antagonistic interaction with Staphylococcus aureus and Escherichia coli was a primary criterion for the preliminary selection of the isolates. Three out of ten strains—PY2.3 (isolated from pollen), BP20.15 and BB10.1 (both isolated from bee bread)—were found to be possible probiotic strains. All these strains are safe for humans (exhibiting  -hemolytic activity) and meet all essential requirements for probiotics in terms of viability in the presence of bile salts and acid conditions, hydrophobicity, auto-aggregation, and co-aggregation with the cells of important human pathogenic bacteria. They also assimilate more than 30% of cholesterol after 24 h of incubation. These three isolates are resistant to penicillin but sensitive (or exhibit moderate resistance) to the other nine antibiotics tested herein. On the basis of whole-genome sequencing, BP20.15 and BB10.1 were classified as B. subtilis and PY2.3 as B. velezensis. Moreover, genomic analyses revealed that all these isolates are potential producers of different antimicrobial compounds, including bacteriocins and secondary metabolites. The outcomes of this study have proven that some of the Bacillus strains isolated from bee pollen or bee bread are potential probiotics.

  • Progress in devulcanization of waste tire rubber: Upcycling towards a circular economy
    • Zaheer ul Haq
    • Teng Ren
    • Xinyan Yue
    • Krzysztof Formela
    • Denis Rodrigue
    • Xavier Colom
    • Tony McNally
    • Dong Dawei
    • Yong Zhang
    • Shifeng Wang
    2025 Express Polymer Letters

    As a complex composite material, tire rubber has always presented significant environmental and waste management concerns due to its non-biodegradability and accumulation in landfills. The devulcanization of tire rubber has emerged as a historical challenge in the field of sustainable rubber engineering since Goodyear invented cross-linking in 1839. This review provides a comprehensive analysis of waste tire recycling processes, focusing on the sources, legislation, management strategies, and utilization across different regions. It explores the multifaceted challenges of devulcanizing rubber, with a specific focus on transitioning from ground tire rubber to the concept of multi-decrosslinking: sulfur bridge breakage, rubber chain depolymerization and micro-nano sized core-shell carbon black. Ideal devulcanization has restricted the release of reinforcing fillers, resulting in devulcanized rubber mainly containing dozens of micron particles, which hinder the wide usage of devulcanized rubber. This review comprehensively assesses the current state-of-the-art techniques for tire rubber devulcanization, including physical, chemical and biological methods. It explores the intricacies of ground tire rubber as a starting material, structural evolution of ground tire rubber during the devulcanization process and the associated challenges in achieving efficient devulcanization while retaining desirable mechanical properties. Furthermore, through an in-depth analysis of recent advancements, limitations and prospects, this paper offers a complete understanding of the challenges faced in tire rubber devulcanization. Considering the technical and environmental aspects of these processes, this work contributes to multi-decrosslinking, the ongoing discourse on sustainable materials development and circular economy initiatives, which pave the way for future innovations in the field of rubber recycling.

  • Proyecto Valija, Cala Vila, Ajuntament de Lliria, P/ Major 1 , 46160 Lliria, Valencia Espana
    • Dominika Krechowicz
    2025

    Projekt "Walizka", koncepcja: prof. dr hab. Zbigniew Szot Uniwersytet Artystyczny w Poznaniu, Wydział Malarstwa i Rysunku. W projekcie wzięło udział 48 artystów z Polski oraz z Czech, Niemiec, Gruzji, Japonii. Koncepcja projektu dotyczy szeroko pojętego tematu podróży. W obecnych czasach zagrożenia COVID-19 słowo „podróż” zaczyna nabierać zupełnie innego znaczenia. Żyjąc i tworząc w izolacji od wielu miesięcy, została stworzona wspólnie autonomiczna kolekcja prac, dedykowanych tylko tej walizce, która teraz jest wysyłana w podróż. Prace i walizka stanowią nierozłączną całość. Koncepcją projektu jest zaprezentowanie prac w wybranych miejscach oraz pozostawienie swojego znaku na wieku walizki. Wystawa Proyecto Valija została zaprezentowana w Cala Vila, Ajuntament de Lliria, P/ Major 1, 46160 Lliria, Valencia w Hiszpanii. Termin realizacji: 03.02.2025 do 09.02.2025

  • Pulsed GTAW joint of P92 steel and Inconel 625: microstructure and mechanical properties
    • Sachin Sirohi
    • Amit Kumar
    • Manohar Singh
    • Dariusz Fydrych
    • Chandan Pandey
    2025 Archives of Civil and Mechanical Engineering

    In the present work, the relationship between microstructure and mechanical properties has been investigated for the dissimilar welded joint of P92 steel and Inconel 625, fabricated using the pulsed current gas tungsten arc welding (GTAW) process. Microstructural investigation revealed that the pulsed current resulted in fner equiaxed dendrites in the bulk weld metal, while columnar dendrites were observed in the weld metal near the interface. A more uniform distribution of the fne secondary phases was observed in FESEM study. The EDS study of the inter-dendritic areas showed alloying element segregation throughout the weld metal, with higher density near the interface. This segregation led to the formation of secondary phases, specifcally MC-type carbides (NbC, TiC), which was confrmed by the EDS analysis. The characterization of the interface between P92 steel and ERNiCrMo-3 fller weld revealed the presence of a fller-defcient zone, marked by features such as islands, peninsulas, and unmixed zones. Elemental difusion and segregation of Nb, Mo, and Ti at the interface were also confrmed through EDS analysis. Tensile testing demonstrated acceptable tensile properties of the welded joint at room temperature, with a tensile strength of 764±8 MPa and elongation of 33±1%, with the sample failing from the P92 base metal. Signifcant hardness variations were observed along the welded joint, with the most notable changes occurring in the P92 heat-afected zone (HAZ). A maximum hardness of 420 HV was recorded in the coarse-grained HAZ of P92, while the inter-critical HAZ of P92 showed a minimum hardness of 215 HV. In addition, considerable hardness variation was noted within the weld metal, corresponding to each welding pass as well as across the transverse direction of the welded joint. The maximum and minimum hardness values in the weld metal were 261±9 and 239±13 HV, corresponding to the center and capping passes, respectively, with an average hardness of 250 HV. The Charpy toughness test also indicated acceptable results, with an impact energy value of 176±8.5 J. The study also provides a detailed discussion on the relationship between microstructure and mechanical properties, highlighting how microstructural features infuence the mechanical performance of the welded joint.

  • Quality Evaluation of Small Features Fabricated by Fused Filament Fabrication Method
    • Dawid Zieliński
    • Mariusz Deja
    • Rui Zhu
    2025 Full text Materials

    The purpose of this research was to evaluate the quality of small features fabricated by the fused filament fabrication (FFF) method. The samples containing circular and square cross-sections through holes with different dimensions, lengths, and orientation angles were printed from ABS (acrylonitrile butadiene styrene) filament. The adopted optical inspection method allowed us to conduct observations of individual features and their measurements. The image processing software was used to determine the accuracy of the dimensions and shape of different cross-sections. Feret’s diameters were used for the evaluation of shape accuracy by comparing them with theoretical dimensions assumed in a 3DCADmodel. Considering the relationship between the real and theoretical dimensions of different features, general empirical equations for predicting the equivalent dimensions were developed. The proposed method of the quality evaluation of small features can be easily implemented and widely applied to other features, especially internal holes with different cross-sections made using various additive manufacturing methods.

  • Quality of Consumed Energy as a Key Element in the Development of Processes of Energy Transformation in the European Union Countries
    • Beata Bieszk-Stolorz
    • Krzysztof Dmytrów
    • Michał Pietrzak
    2025 ENERGIES

    The process of energy transformation is one of the crucial elements of the process of improvement of the quality of consumed energy. The aim of the research is to assess the European Union countries in terms of the quality of their consumed energy and the speed of adaptation of this aspect of the energy transformation process. We assess the quality of consumed energy by means of the synthetic measure obtained by means of the dynamic version of the COmplex PRoportional ASsessment (COPRAS) method. We compare the countries with the dynamics of the energy transformation process by means of the dynamic time warping method and the hierarchical clustering. Obtained results indicate the best countries with respect to the quality of consumed energy were Malta, Austria, and Germany, and the worst ones—Poland, Czechia, and Slovakia. The process of energy transformation was evolving in the right direction—the quality of consumed energy increased. This increase was the fastest in Malta, Luxembourg, and Poland. The direction for future research is extending the set of variables to also consider other aspects of the energy transformation.

  • Quasilinear elliptic problem in anisotropic Orlicz–Sobolev space on unbounded domain
    • Karol Wroński
    2025 ANNALI DI MATEMATICA PURA ED APPLICATA

    We study a quasilinear elliptic problem $-\text{div} (\nabla \Phi(\nabla u))+V(x)N'(u)=f(u)$ with anisotropic convex function $\Phi$ on the whole $\R^n$. To prove existence of a nontrivial weak solution we use the mountain pass theorem for a functional defined on anisotropic Orlicz-Sobolev space $\WLPhispace(\R^n)$. As the domain is unbounded we need to use Lions type lemma formulated for Young functions. Our assumptions broaden the class of considered functions $\Phi$ so our result generalizes earlier analogous results proved in isotropic setting.

  • RAGN-R: A multi-subject ensemble machine-learning method for estimating mechanical properties of advanced structural materials
    • Farzin Kazemi
    • A. Ӧzyüksel Çiftçioğlu
    • Torkan Shafighfard
    • Neda Asgarkhani
    • Robert Jankowski
    2025 COMPUTERS & STRUCTURES

    The utilization of advanced structural materials, such as preplaced aggregate concrete (PAC), fiber-reinforced concrete (FRC), and FRC beams has revolutionized the field of civil engineering. These materials exhibit enhanced mechanical properties compared to traditional construction materials, offering engineers unprecedented opportunities to optimize the design, construction, and performance of structures and infrastructures. This formal description elucidates the inherent mechanical properties of PAC, FRC, and FRC beams, explores their diverse applications in civil engineering projects. This research aims to propose a surrogate multi-subject ensemble machine-learning (ML) method (named RAGN-R) for estimating mechanical properties of aforementioned advanced materials. The proposed learning approach, RAGN-R, integrates Random forest, Adaptive boosting, and GradieNt boosting techniques, employing a Ridge regression framework for stacking the ensemble. For this purpose, three experimental dataset have been prepared to determine the capability of RAGN-R and the results of the study have been compared with six well-known ML models. It is noteworthy that the proposed RAGN-R has the ability of self-optimizing the hyperparameters, which facilitate the adoptability of the model with engineering problems. Moreover, three datasets have been investigated to show the ability of the RAGN-R for diverse problems. Different performance evaluation metrics have been conducted to present results and compare ML models, which confirms the highest performance of RAGN-R (i.e., 97.7% accuracy) in handling complex relationships and improving overall prediction accuracy.

  • Ranking the rankers. An analysis of science-wide author databases of standardised citation indicators
    • Marta Kuc-Czarnecka
    • Andrea Saltelli,
    2025 SCIENTOMETRICS

    In this paper, we investigate the properties of the science-wide author databases’ stand- ardised citation indicators produced since 2015 by a team of researchers led by John P. A. Ioannidis. Based on data from Scopus, the researchers published close to 200,000 of the most-cited authors across all scientific fields and ranked them using a composite indica- tor that includes six citation metrics (total citations; Hirsch h-index; coauthorship-adjusted Schreiber hm-index; the number of citations to papers as a single author; the number of citations to papers as a single or first author; and the number of citations to papers as a sin- gle, first, or last author). We look at the quality of these new rankings to suggest improve- ments. Specifically, we try to correct for correlation among variables and the deviation between the purported weights of the variables, as declared by the developers, and the effective weights based on the theory of global sensitivity analysis. We aim to ascertain if our modified measure is an improvement over the existing one by addressing the issue of redundant data due to correlated variables. Lacking a ground truth based on a ‘true’ ranking possibly supported by independent data, we content ourselves for the purpose of the present analysis with benchmarking against a best practice. Given that most practition- ers have reservations against linear aggregation approaches (Munda, Social multi-criteria evaluation for a sustainable economy, Springer, Berlin, 2008; Balinski & Laraki, Major- ity judgment: Measuring, ranking, and electing, Mass, 2011; Arrow, Social choice and individual values, Martino Fine Books, Eastford, 2012 [1951]), while those based on the method of Condorcet are considered by many as a good practice (Munda, Social multi-cri- teria evaluation for a sustainable economy, Springer, Berlin, 2008; Roy, Multicriteria meth- odology for decision aiding, Springer, Cham, 1996), we entrust of defence of our modified ranking on a pairwise comparison between linear aggregation and Condorcet

  • RCS Enhancement of Millimeter Wave LTCC Van Atta Arrays With 3-D Printed Lenses for Chipless RFID Applications
    • Kamil Trzebiatowski
    • Weronika Kalista
    • Łukasz Kulas
    • Krzysztof Nyka
    2025 Full text IEEE Antennas and Wireless Propagation Letters

    In this paper, we present a new method to enhance the radar- cross section (RCS) of Van Atta arrays which can be used in chipless radio-frequency identification tags operating in millimeter wave frequency bands. Small planar Low-Temperature Co-fired Ceramic (LTCC) Van Atta arrays, that are durable and can operate in harsh environments, are combined with 3-D printed lenses to increase or modify the shape of their RCS by up to 10 dB. The lenses are uniform in one direction to maintain a wide RCS angular range of the underlying Van Atta arrays. They are manufactured using affordable 3-D printing stereolithography (SLA) process using high-performance resin. The resulting manufactured and measured Van Atta retrodirective arrays integrated with lenses exhibit measured RCS levels up to -28 dBsm at 24 GHz frequency. Moreover, the proposed approach allows LTCC Van Atta tags to be easily modified and reused by exchanging their lenses to adapt them to a new application. To the best of the authors' knowledge, this is the first time an experimental evaluation of lenses combined with Van Atta arrays has been presented. This novel technique can also be integrated with other RCS enhancement methods to further increase RCS levels.

  • Replica road pavements for rolling resistance measurements
    • Jerzy Ejsmont
    • Grzegorz Ronowski
    • Sławomir Sommer
    • Wojciech Owczarzak
    • Truls Berge
    2025 Road Materials and Pavement Design

    Due to the need to strictly control the measurements, tire manufacturers strive to conduct most of the tests indoors. This allows them to perform them regardless of weather conditions, all the yearlong. Currently, a lot of research concerns the rolling resistance of tires. These include both development activities and mandatory measurements related to the granting of environmental labels. Unfortunately, standardized tests are conducted on smooth steel drums, which has a very negative impact on the representativeness of the results. To improve the representativeness, it is necessary to ensure realistic conditions of interaction between the tire and the road by guaranteeing that the texture of the roadwheel facility drum is as close as possible to the texture of the actual road pavement. The article presents in details the technologies for making replicas of road pavements that allow for realistic conditions of interaction between the tire and the road.

  • Resonant and nonresonant excitation of waves in a planar magnetosonic flow
    • Anna Perelomova
    2025 CONTRIBUTIONS TO PLASMA PHYSICS

    Forced propagation of perturbations in a magnetosonic wave are considered. The driving force may be caused by stimulated Mandelstam–Brillouin scattering of optic waves or by intense magnetosonic exciter. Some heating-cooling function which takes into account radiative cooling and unspecified heating is taken into consideration, as well as nonlinearity of a medium. Both these factors make the excitation particular. The analytical and numerical evaluations reveal that forced oscillations differ essentially from the free propagation and depend on a number of dimensionless parameters such as the ratio of speed of exciter to the eigen speed of excited wave, the ratio of speed of an excited wave to its eigen speed, and the dimensionless magnitude of an exciter. Forced excitation is resonant if speed of an exciter coincides with the eigen speed of excited wave but may give rise to the excited perturbations with the speed different from the eigen one. The preliminary evaluations may be helpful for the controlled excitation of perturbations in natural and laboratory plasma systems and indication of the parameters of an exciter.

  • Responsive and proactive market orientation and hospital financial performance: The mediating effect of service program innovativeness
    • Dariusz Dąbrowski
    • Wioletta Kukier
    • Anna Tybińkowska
    2025 Journal of Entrepreneurship, Management and Innovation

    PURPOSE: The study aims to investigate the direct and indirect relationships among market orientation, service program innovativeness, and the financial performance of hospitals. Two types of market orientation – responsive and proactive – were considered, along with two dimensions of service program innovativeness: meaningfulness and novelty. METHODOLOGY: T he study gathered data through a survey conducted on a random sample of 204 Polish hospitals. Structural equation modeling was used to analyze the data, test a conceptual model designed as a parallel two-mediator model, and validate the hypotheses. FINDINGS: The work revealed both direct and indirect effects. In terms of direct effects, the study found that implementing a responsive market orientation positively influences the meaningfulness of a hospital’s service program but has no impact on its novelty. Conversely, the implementation of a proactive market orientation has a positive influence on both the meaningfulness and novelty of the program. Furthermore, the meaningfulness and novelty of the program contribute positively to the hospital’s f inancial performance. In terms of indirect effects, the study identified mediation phenomena: a responsive market orientation positively affects a hospital’s financial performance through the meaningfulness of the service program, while a proactive market orientation enhances financial performance through the novelty of the program. IMPLICATIONS: The study contributes to the current understanding, confirming the positive impact of a proactive market orientation on innovations within the organization while contradicting the view that a responsive market orientation supports these innovations. Additionally, the results support the idea that innovations within the organization have a positive impact on its outcomes. The study also reveals specific mechanisms that influence market orientation on organizational outcomes, indicating that a responsive orientation affects a service provider’s outcomes through the meaningfulness of its service program, while a proactive orientation influences outcomes through the novelty of the program.

  • Restrained differential of a graph
    • Abel Cabrera-Martinez
    • Magda Dettlaff
    • Magdalena Lemańska
    • Juan Alberto Rodriguez-Velazquez
    2025 Full text Discussiones Mathematicae Graph Theory

    Given a graph $G=(V(G), E(G))$ and a vertex $v\in V(G)$, the {open neighbourhood} of $v$ is defined to be $N(v)=\{u\in V(G) :\, uv\in E(G)\}$. The {external neighbourhood} of a set $S\subseteq V(G)$ is defined as $S_e=\left(\cup_{v\in S}N(v)\right)\setminus S$, while the \emph{restrained external neighbourhood} of $S$ is defined as $S_r=\{v\in S_e : N(v)\cap S_e\neq \varnothing\}$. The restrained differential of a graph $G$ is defined as $\partial_r(G)=\max \{|S_r|-|S|:\, S\subseteq V(G)\}.$ In this paper, we introduce the study of the restrained differential of a graph. We show that this novel parameter is perfectly integrated into the theory of domination in graphs. We prove a Gallai-type theorem which shows that the theory of restrained differentials can be applied to develop the theory of restrained Roman domination, and we also show that the problem of finding the restrained differential of a graph is NP-hard. The relationships between the restrained differential of a graph and other types of differentials are also studied. Finally, we obtain several bounds on the restrained differential of a graph and we discuss the tightness of these bounds.