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Bulletin of the Polish Academy of Sciences Technical Sciences

Bulletin of the Polish Academy of Sciences Technical Sciences

Description

The Bulletin of the Polish Academy of Sciences Technical Sciences has been published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences since the establishment of PAS in 1952. The journal is peer-reviewed and issued in electronic format. It aims to publish original, high-quality papers from multidisciplinary engineering sciences, with preferred topics including:

  • Artificial and Computational Intelligence,
  • Biomedical Engineering and Biotechnology,
  • Civil Engineering,
  • Control, Informatics and Robotics,
  • Electronics, Telecommunication and Optoelectronics,
  • Mechanical and Aeronautical Engineering, Thermodynamics,
  • Material Science and Nanotechnology,
  • Power Systems and Power Electronics.

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Journal Metrics:
JCR Impact Factor 2024: 1.1
5 Year Impact Factor 2023: 1.0
CiteScore 2024: 2.7
SCImago Journal Rank (SJR) 2023: 0.271
Source Normalized Impact per Paper (SNIP) 2023: 0.517
Ministry of Education and Science: 100 points

Abbreviated title: Bull. Pol. Acad. Sci. Tech. Sci.
ISSN
ISSN 2300-1917

Editorial Board 2023-2025

Editor-in-Chief:

A. Rogalski, Military University of Technology

Honorary (Past) Editor-in Chief:

T. Kaczorek, Warsaw University of Technology

M.P. Kaźmierkowski, Warsaw University of Technology

Deputy Editor-in-Chief:

B. Błachowski, Institute of Fundamental Technological Research PAN

M. Mrozowski, Gdansk University of Technology

Board of Topical Co-editors:

Artificial and Computational Intelligence

B. Sawicki and T. Leś, Warsaw University of Technology

Biomedical Engineering and Biotechnology

P. Ładyżyński, Institute of Biocybernetics and Biomedical Engineering PAN

Civil Engineering

L. Czarnecki, Building Research Institute, ITB, Warsaw

Ł. Sadowski, Wroclaw University of Science and Technology

Control, Robotics and Informatics

J. Klamka and A. Babiarz, Silesian Technical University

J. Stefanowski, Poznan University of Technology

Electronics, Telecommunication and Optoelectronics

M. Mrozowski and P. Kryszkiewicz, Gdansk University of Technology

Mechanical and Aeronautical Engineering, Thermodynamics

B. Błachowski, Institute of Fundamental Technological Research PAN

G. Zboiński, Institute of Fluid-Flow Machinery PAN and University of Warmia and Mazury in Olsztyn

Materials Science and Nanotechnology

B. Major and P. Czaja, Institute of Metallurgy and Materials Science PAN

Power Systems and Power Electronics

J. Rąbkowski and M. Jasiński, Warsaw University of Technology

International Editorial Advisory Board

R. Asthana, University of Wisconsin-Stout, Menomonie, USA

Xu Binshi, China Association of Plant Engineering, Beijing, P.R. China

F. Blaabjerg, Aalborg University, Denmark

C. Cecati, University of L’Aquila, Italy

A. Cichocki, RIKEN Institute, Tokyo, Japan

M. David, National Polytechnique de Toulouse, France

R. Ebner, Materials Centre Leoben, Leoben, Austria

E. Fornasini, University of Padova, Padova, Italy

L.G. Franquelo, University of Sevilla, Spain

M. Gad-el-Hak, Virginia Commonwealth University, Richmond, USA

M. Giersig, Free University of Berlin, Germany

D. van Gemert, Catholic University Leuven, KU Leuven, Belgium

L. Keviczky, Hungarian Academy of Sciences, Budapest, Hungary

V. Kučera, Czech Technical University in Prague, Prague, Czech Republic

R. Kennel, Technical University Munich, Germany

T.A. Kowalewski, Institute of Fundamental Technological Research PAN

E. Levi, Liverpool John Moore University, UK

G. Maier, Technical University of Milan, Milan, Italy

K.F. Man, City University of Hong Kong,

R. Maniewski, Institute of Biocybernetics and Biomedical Engineering PAN

H.A. Mang, Austrian Academy of Sciences, Vienna, Austria

H. Mihashi, Tohoku University, Aoba-ku, Sendai, Japan

S. Mindess, University of British Columbia, Vancouver, Canada

D.A. Mlynski, University of Karlsruhe, Karlsruhe, Germany

A.S. Nowak, University of Michigan, Ann Arbor, USA

K. Ohnishi, Keio University, Yokohama, Japan

A. Öberg, Linköping University, Linköping, Sweden

W. Pedrycz, University of Alberta, Canada

M. Razeghi, Northwestern University, Evanston, USA

J. Rodriguez, University of Andres Bello, Santiago, Chile

J.V. Sloten, Catholic University Leuven, Leuven, Belgium

B.M. Wilamowski, University of Auburn, Alabama, USA

A.L. Yarin, University of Illinois at Chicago, USA

Du Xiangwan, Chinese Academy of Engineering, China

J. Żurada, Department of Computer Engineering, University of Louisville, USA

Editorial Office:

Pałac Kultury i Nauki

Wydział IV Nauk Technicznych PAN

Pl. Defilad 1

PL 00-901 Warszawa

Managing Editor:

Renata Podraza, e-mail: Renata.Podraza@pan.pl

Finance:

Katarzyna Łasak, e-mail: Katarzyna.Lasak@pan.pl

The Bulletin of the Polish Academy of Sciences Technical Sciences is an open access journal with all content available with no charge in full text version.


The journal content is available under the licencse CC BY 4.0 https://creativecommons.org/licenses/by/4.0/.

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Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access

1 Data structure better than labels? Unsupervised heuristics for SVM hyperparameter estimation
Michał Cholewa , Michał Romaszewski , Przemysław Głomb
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e155891 | DOI: 10.24425/bpasts.2025.155891
Keywords: SVM classification parameters selection unsupervised
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Abstract

Classification is one of the main areas of pattern recognition research, and within it, Support Vector Machine (SVM) is one of the most popular methods outside of the field of deep learning – and a de facto reference for many Machine Learning approaches. Its performance is determined by parameter selection, which is usually achieved by a time-consuming grid search cross-validation procedure (GSCV). That method, however, relies on the availability and quality of labelled examples and thus, when those are limited, can be hindered. To address this problem, several unsupervised heuristics exist that utilise the characteristics of the dataset to select parameters, rather than relying on class label information. While an order of magnitude faster, they are scarcely used under the assumption that their results are significantly worse than those of grid search. To challenge that assumption, we have surveyed several heuristics for SVM parameter selection and tested them against GSCV on over 30 standard classification datasets. The results demonstrate their high accuracy, with performance in terms of statistical significance comparable to GSCV, opening up an avenue for reliable label-free model defaults in resource-constrained settings e.g., edge devices or rapid prototyping.
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Authors and Affiliations

Michał Cholewa
Michał Romaszewski
ORCID: ORCID
Przemysław Głomb
2 Towards sustainable wireless rechargeable sensor networks: a federated multi-agent reinforcement learning approach for cooperative wireless charging
C.N. Vanitha , P. Anusuya
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e155897 | DOI: 10.24425/bpasts.2025.155897
Keywords: wireless sensor networks wireless charging federated reinforcement learning multi-agent reinforcement learning energy efficiency
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Abstract

Wireless rechargeable sensor networks (WRSNs) face persistent energy limitations due to the finite battery capacity of sensor nodes, which can compromise network reliability in remote or dynamic environments. To address these challenges, this paper proposes a novel federated multi-agent reinforcement learning (FedRL-MARL) framework for adaptive and cooperative energy replenishment using multiple mobile wireless chargers (MWCs). Unlike traditional centralized approaches, FedRL-MARL leverages decentralized policy learning, enabling each MWC to train on local observations while contributing to a globally aggregated model through federated updates. The problem is formulated as a Markov decision process (MDP), allowing agents to make intelligent charging and routing decisions in real time, even in the presence of obstacles and changing node demands. Simulation results demonstrate that the proposed method improves network lifetime by up to 16%, enhances energy efficiency by over 9%, and significantly reduces communication overhead when compared to state-of-the-art approaches. This research sets a strong direction for scalable, decentralized energy replenishment in next-generation sensor networks. It lays the groundwork for resilient, efficient power management across diverse applications such as smart cities, environmental sensing and autonomous IoT deployments.
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Authors and Affiliations

C.N. Vanitha
1
ORCID: ORCID
P. Anusuya
1
ORCID: ORCID
  1. Department of Information Technology, Karpagam College of Engineering, Coimbatore, India
3 Development of low-emission photocatalytic cement composites with co-ground TiO2-fly ash and TiO2-calcium carbonate systems
Agnieszka Ślosarczyk , Izabela Klapiszewska , Patryk Jędrzejak , Marta Thomas , Łukasz Klapiszewski
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e155898 | DOI: 10.24425/bpasts.2025.155898
Keywords: low-emission composites titanium dioxide calcium carbonate fly ash photocatalytic activity
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Abstract

This study presents an innovative method for producing low-emission cement composites with photocatalytic properties by partially replacing Portland cement with fly ash, ground granulated blast furnace slag, and calcium carbonate. Novel ground systems combining fly ash-TiO2 or calcium carbonate-TiO2 were synthesized via high-energy ball milling to enhance dispersion and minimize TiO2 agglomeration. The modified composites exhibited improved hydration kinetics, including reduced setting times and up to 50% lower cumulative hydration heat. Mechanical tests confirmed comparable or superior compressive and flexural strengths as compared with the reference materials. All TiO2-containing composites showed UV-induced photocatalytic activity, with anatase-based systems yielding the best results. Carbon footprint analysis confirmed the environmental benefits, particularly in reducing CO2 emissions. These findingssupport the development of multifunctional, sustainable cementitious materials for eco-efficient construction.
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Authors and Affiliations

Agnieszka Ślosarczyk
1
Izabela Klapiszewska
1
Patryk Jędrzejak
1
Marta Thomas
1
Łukasz Klapiszewski
1 2 3
ORCID: ORCID
  1. Institute of Building Engineering, Faculty of Civil and Transport Engineering, Poznan University of Technology, PL-60965 Poznan, Poland
  2. Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, PL-60965 Poznan, Poland
  3. Interdisciplinary Centre for Ecotechnology, Poznan University of Technology, PL-60965 Poznan, Poland
4 High-Performance Control of Permanent Magnet Synchronous Motor using a Finite-Time Sliding Mode Observer and Super-Twisting Algorithm
Jing Nie , Yong Li , Gang Li
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e155896 | DOI: 10.24425/bpasts.2025.155896
Keywords: permanent magnet synchronous motor (PMSM) super-twisting sliding mode controller (STSM) finite time sliding mode observer (FTSMO) perturbation resistance
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Abstract

To enhance the tracking performance of the permanent magnet synchronous motor (PMSM) drive system in the face of changing operating conditions, such as variations in internal parameters and external load disturbances, this study proposed a new composite control strategy that combines the super-twisting sliding mode controller (STSM) with the finite-time sliding mode observer (FTSMO). The proposed methodology synergistically integrates the enhanced tracking precision and robust disturbance rejection properties inherent to the Second-order Tracking-Sliding Mode (STSM) controller with an innovative Finite-Time Sliding Mode Observer (FTSMO), thereby achieving significant improvements in system state estimation accuracy. The stability of the closed-loop PMSM drive system under the STSM+FTSMO framework is thoroughly analyzed and established using Lyapunov theory. The proposed composite control strategy’s effectiveness is confirmed through both simulations and experimental outcomes. These findings illustrate that the proposed approach significantly surpasses conventional control methods, especially in managing external disturbances within the PMSM system. Significant enhancements are evident in start-up response, robustness against load variations, convergence speed, and steady-state performance.
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Authors and Affiliations

Jing Nie
Yong Li
Gang Li
5 Experimental performance analysis of an AMR controlled by a hybrid MPC-PID method
Murat Orkan Celik , Murat Koseoglu , Furkan Nur Deniz
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e156764 | DOI: 10.24425/bpasts.2025.156764
Keywords: ROS2 AMR MPC-PID system identification
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Abstract

Recent advances in decision-making algorithms used in mobile robotics require more advanced and adaptive control strategies. Model predictive control (MPC) is one of the prominent strategies to manage diverse kinds of complex dynamic systems. Despite their widespread adoption in industrial robotics owing to their structural simplicity and ease of implementation, proportional-integral-derivative (PID) controllers exhibit notable limitations in effectively addressing process variations and system constraints, particularly those arising from mechanical constraints on joint positions and velocities. As autonomous mobile robots (AMRs) have been increasingly deployed in various and demanding applications, the need for more advanced control algorithms has become critical. In this study, a novel hybrid control framework integrating MPC and PID strategies is proposed and experimentally validated on a real-world differential drive robot, aiming to enhance tracking accuracy and overall operational performance. The system model of the TurtleBot3 robot is identified using the System Identification Toolbox and validated through extensive motion tests on the real robot by using Robot Operating System 2. The proposed control scheme combines the predictive capabilities of MPC with the reactive nature of PID to facilitate improved management of system constraints, aiming to improve the performance of AMR in controlling both linear and angular velocities. Experimental results show that the hybrid MPC-PID controller exhibits better performance by reducing tracking errors while maintaining reliability and robustness characteristics over a conventional PID controller. These results demonstrate that the hybrid MPC-PID approach provides a more effective solution for dynamic control tasks in mobile robotic systems, particularly in scenarios requiring high accuracy and reliability.
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Authors and Affiliations

Murat Orkan Celik
1
ORCID: ORCID
Murat Koseoglu
2
ORCID: ORCID
Furkan Nur Deniz
2
ORCID: ORCID
  1. Department of Electrical and Electronics Engineering, Institute of Science, Inonu University, Malatya, Türkiye
  2. Department of Electrical and Electronics Engineering, Faculty of Engineering, Inonu University, Malatya, Türkiye
6 Synergistic effect of additives on reducing asphalt binder aging
Mateusz Marek Iwański , Małgorzata Durlej , Karolina Janus
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e156767 | DOI: 10.24425/bpasts.2025.156767
Keywords: Warm Mix Asphalt (WMA) ageing inhibitors sustainable pavements bio-based additives rheological properties aging process
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Abstract

As an organic material, asphalt binder undergoes a aging process, the intensity of which depends on the stage of its technological use. The binder is exposed to high temperatures, which cause its oxidation. The viscoelastic properties of the binder deteriorate. Research is being conducted to limit the effects of asphalt aging. One of the directions is individually dosed chemical additives to be used in the binder. In the article, a combination of synthetic wax (SWLC) and tall oil amidopolyamine (TOA) was used for the first time in the binder, in concentrations of 1.0%, 1.5%, 2.0% and 2.5% and in the amounts of 0.0%, 0.2%, 0.4% and 0.6% by weight in relation to asphalt. The function of these additives is to act as aging inhibitors and to improve the basic properties of the binder. The resulting binders containing combinations of SWLC and TOA were then subjected to short-term and long-term aging. The effects of aging on penetration at 25◦C, softening point and dynamic viscosity were analyzed, and their aging indices were determined. The penetration index and plasticity range of the modified asphalt were also determined. A synergistic effect of SWLC and TOA was observed at the recommended amounts of 2.0% and 0.4% relative to the asphalt, which ensured a favorable change in the analyzed binder parameters. The results obtained are therefore of significant importance for road engineering practice in the design and construction of durable and sustainable road pavements and the possibility of using this type of binder in the environmentally friendly Warm Mix Asphalt technology.
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Authors and Affiliations

Mateusz Marek Iwański
1
ORCID: ORCID
Małgorzata Durlej
1
ORCID: ORCID
Karolina Janus
1
ORCID: ORCID
  1. Kielce University of Technology, Faculty of Civil Engineering and Architecture, Al. Tysi ˛aclecia P.P. 7, 25-314 Kielce, Poland
7 Evaluating geometric quality and accuracy of 3D building models: a concept of 3D model evaluation method
Przemysław Klapa
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e156770 | DOI: 10.24425/bpasts.2025.156770
Keywords: 3D modelling model quality evaluation solid model mesh model parametric modeling
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Abstract

Evaluation of 3D building model quality is central to civil engineering, geodesy, architecture and the construction industry as it facilitates the assessment of the model’s accuracy, completeness and interoperability. The article presents a concept of a versatile method for evaluating the quality of 3D building models, the 3D model evaluation method. It can compare models regardless of their data sources, modelling techniques, visualization and file format. The method covers key quality aspects such as completeness, which reflects the degree to which object components are represented; accuracy, which concerns geometric and positioning integrity; and interoperability, which includes the model’s compliance with standards, editability and reusability. The author investigated a range of 3D modelling approaches, including mesh, solid and parametric models derived from a variety of data sources. The proposed evaluation method is founded on analyzing model attribute values for selected criteria followed by visualization of these values on a radar chart. The model quality index, normalized to [0; 1], quantifies the 3D model quality. The results demonstrate the method’s effectiveness for 3D model evaluation regarding both geometric and non-geometric aspects. The method can be applied in GIS, BIM, spatial analyses, civil engineering and environmental engineering. It provides a single pipeline for classifying and comparing different types of models. The 3D model evaluation method provides a universal, structured and practical basis for comparing 3D models across sources and techniques, ensuring result comparability and consistent quality reporting.
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Authors and Affiliations

Przemysław Klapa
1
ORCID: ORCID
  1. Department of Geodesy, University of Agriculture in Krakow, al. Mickiewicza 21, 31-120 Krakow, Poland
8 An approximate analytical solution of the gear meshing problem based on MSM using DynPy Python library
Krzysztof Twardoch , Krzysztof Kaczmarzyk , Grzegorz Długopolski , Bogumił Chiliński
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e155895 | DOI: 10.24425/bpasts.2025.155895
Keywords: gear meshing parametric vibrations Time-Varying Mesh Stiffness (TVMS) Multiple Scales Method (MSM) analytical modeling numerical simulation drive system gear dynamics
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Abstract

The paper presents the mathematical and numerical analysis of a 1-DOF (one-degree-of-freedom) dynamic model of the helical gear with Time-Varying Mesh Stiffness (TVMS). The article aims to determine an analytical solution for the presented model using a proprietary computational environment and to verify the results with numerical simulations and other solutions available in the literature. The paper presents the determination of a 2-DOF (two-degree-of-freedom) dynamic model and its reduction to a 1-DOF model. The concept of the created environment, the applied libraries, and the application basics are discussed. Based on the work effects, an analytical solution using the Multiple Scales Method (MSM) was found and positively verified. The article presents the convergence of the obtained results and the added value as an analytical solution. This confirms the effectiveness of the novelty approach, which provides a framework that bridges the gap between directly determining a solution and manual calculations. It should be noted that time complexity is especially important for performance computing. Observations suggest significant advantages to using an analytical solution due to its precision and relatively low computational cost. Although obtaining an analytical solution is more time-consuming, it reduces the possibility of errors with numerical methods.
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Authors and Affiliations

Krzysztof Twardoch
ORCID: ORCID
Krzysztof Kaczmarzyk
Grzegorz Długopolski
Bogumił Chiliński
ORCID: ORCID
9 Wave-shaped wire extensometer for linear displacement measurement
Elżbieta Matus
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e155899 | DOI: 10.24425/bpasts.2025.155899
Keywords: extensometer metrology strain gauges
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Abstract

This article presents the concept and the method of operation of an innovative device for the measurement of relative displacements, and a study of its metrological properties. The mechanical system of the proposed measuring instrument is similar to the systems of existing wire displacement transducers. The construction of previously known devices for measuring relative displacements containing a measuring wire (wire strain gauges, wire dilatometers) involves direct attachment of the wire to the anchors of the device, through either additional elastic elements or mechanical transmissions. In this measuring instrument, the elastic sensor element has been replaced with a wavy wire that is attached directly to the anchors of the device. The measuring range of this device is four times as large as that of a wire displacement transducer with a measuring base of the same length. The increased measuring range will enable the use of this equipment for measuring relative displacements of building elements in the range 2–3 mm, with a measurement uncertainty of 0.025%.
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Authors and Affiliations

Elżbieta Matus
1
ORCID: ORCID
  1. Strata Mechanics Research Institute, Polish Academy of Sciences, Poland
10 The effect of the deformation of the face throttle surface on the operation of the balancing disk of a multistage centrifugal pump
Yuliia Tarasevych , Nataliia Sovenko , Kinga Chronowska-Przywara
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e156766 | DOI: 10.24425/bpasts.2025.156766
Keywords: annual throttlle face throttle axial force multistage pump FSI
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Abstract

This paper presents selected results of numerical and analytical analysis of a traditional design of an axial force balancing system in a multistage centrifugal pump. The value of the axial force generated in the face throttle of such a system is directly influenced by the geometry of the throttles: length and height. In the process of operating a multistage pump, the surfaces that form the face throttle are deformed due to high values of pressure or temperature. Changing geometry results in a change in the pressure distribution, and thus in the value of the generated axial force and hydraulic losses. The analytical approach provides a simplified theoretical estimation of disc deflection and force balance, while the numerical simulations capture the detailed pressure distribution and corresponding structural response for different face gap values. The practical value of this research lies in providing a deeper understanding of the relationship between balance disc deformation and axial force. The results enable more accurate selection of disc geometry and face gap value, helping to minimize residual thrust on bearings and hydraulic losses on the automatic balancing device.
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Authors and Affiliations

Yuliia Tarasevych
1
ORCID: ORCID
Nataliia Sovenko
2
ORCID: ORCID
Kinga Chronowska-Przywara
1
ORCID: ORCID
  1. AGH University of Krakow, Kraków, Poland
  2. Sumy State University, Sumy, 40014, Ukraine
11 On compliance minimization by biomimetic regularization method
Michał Nowak , Jan Sokołowski , Antoni Żochowski , Jan Polak
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e155900
Keywords: mechanical design free boundary problem biometric structural optimalization optimality conditions trabecular bone remodeling
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Abstract

The standard approach to mechanical design is based on strength hypotheses. However, the structural optimization methods do not take into account this important condition determining the correctness of the engineering solution. The situation is different in the case of biological systems, where reference to material strength is a basic condition for the formation of functional mechanically loaded systems. The team developed an optimization system modeled on the phenomenon of bone remodeling, based on rigorous theoretical studies in the field of material continuum optimization, where the condition for achieving the optimal solution is the equalization of strain energy density on the structural surface. The new idea presented in this paper is to link this condition with the strength properties of the material. Furthermore the strength hypotheses are expressed in terms of strain energy. The aim of the research presented in this paper is to precisely estimate the relationship between the condition of a constant value of the strain energy density on the structural surface and the material strength, according to yield criteria. The given numerical examples contain a reference to the analytical results and indicate a unique feature of the presented method. The use of the notion of insensitivity zone concept for building the biomimetic structural optimization system allows regularization without focusing on the existence of the Lagrange multiplier correspondence to the volume constraint. The approach presented in the paper can be used by engineers as a method for structural optimization no longer bound to the phenomenon of trabecular bone remodeling. Also discussed is the problem of numerical implementation and the necessary modification of the position and size of the insensitivity zone to ensure that the result is achieved by numerical means. This results requires the development of appropriate heuristics but allows to achieve similar results regardless of the initial configuration. However, the discussion of the use of observations of Nature in mechanical design remains open.
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Authors and Affiliations

Michał Nowak
ORCID: ORCID
Jan Sokołowski
Antoni Żochowski
Jan Polak
12 Predictive Algorithms for Determining Blowing Pressure in a Pipe Organ
Damian T. Węgrzyn , Piotr Wrzeciono , Alicja A. Wieczorkowska
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e156771 | DOI: 10.24425/bpasts.2025.156771
Keywords: pipe organ blowing pressure reconstruction machine learning generative artificial intelligence
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Abstract

The reconstruction of a pipe organ involves determining the blowing pressure. The lack of information about the pressure value significantly prolongs the process of instrument restoration. In addition, it may even result in irreversible damage to the pipes, as the adjustment of the sound parameters that depend on the pressure requires changing the physical structure of the pipes. In this paper, we provide a methodology for determining the blowing pressure in a pipe organ. We also present a formula describing the air pressure in the pipe foot, depending only on the height of the pipe’s cut-up and the fundamental frequency. We apply machine learning to determine the blowing pressure, based on the parameters of only a percentage of pipes. Moreover, we use generative artificial intelligence, which achieves outstanding prediction accuracy. We conclude that the height of the cut-up and the fundamental frequency allow determining the blowing pressure. The more pipes, the higher the accuracy, but even 10% of pipes can be sufficient.
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Authors and Affiliations

Damian T. Węgrzyn
Piotr Wrzeciono
Alicja A. Wieczorkowska
13 Production of environmentally friendly, sustainable insulation material: Fly ash-based geopolymer
Evren Arioz
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e156768 | DOI: 10.24425/bpasts.2025.156768
Keywords: geopolymer fly ash foam thermal conductivity microstructure
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Abstract

Geopolymer foams are sustainable, environmentally friendly, and low-cost materials. In this research, fly ash-based geopolymer foams were synthesized using a mixture of sodium hydroxide, sodium silicate, and hydrogen peroxide as the foaming agent. At a constant 80◦C curing temperature, curing periods were varied to 4, 15, and 24 hours, while hydrogen peroxide ratios were varied to 0.5%, 1%, 1.5%, and 2%. The effects of peroxide amount and curing duration on thermal conductivity, density, compressive strength, and microstructural properties were examined. The densities and thermal conductivity values decreased with increasing curing duration and hydrogen peroxide ratio. The lowest density was recorded as 1070 kg/m3 for the sample prepared with 2% hydrogen peroxide and cured for 24 hours. Conductivity values varied from 0.247 to 0.108 W/m K. The highest compressive strength value obtained was 9.3 MPa. Quartz and mullite were identified as crystalline phases. The hydrogen peroxide content did not significantly affect the crystalline structures. The weight loss decreased as the hydrogen peroxide ratio increased, according to TGA analysis. BET analysis indicated that the pore size distribution shifted to the smaller pore size region as the peroxide concentration increased. SEM analyses showed a reduction in the presence of unreacted fly ash residues in the samples containing 1.5% and 2% hydrogen peroxide. The geopolymer foams produced in this experimental study meet RILEM requirements for structural and insulating concrete materials with respect to thermal conductivity and compressive strength.
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Authors and Affiliations

Evren Arioz
1
ORCID: ORCID
  1. Department of Chemical Engineering, Faculty of Engineering, Eskisehir Technical University, 26555, Turkey
14 Improved snake optimization algorithm for parameter identification based on the genetic algorithm
Baolu Yang , Liangming Wang , Jian Fu
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e156797 | DOI: 10.24425/bpasts.2025.156797
Keywords: projectile aerodynamic parameter identification improved snake optimization algorithm Kalman filtering genetic algorithm integration
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Abstract

To address the issue that traditional snake optimization (SO) algorithms tend to become trapped in local optima when identifying aerodynamic parameters of high-spin projectiles – where complex flight dynamics and measurement noise further complicate the process – this paper proposes an enhanced snake optimization algorithm integrated with genetic algorithm (GA) mechanisms. Specifically, the improved algorithm incorporates GA-based selection and crossover operations into the SO framework, aiming to strengthen global search capability by simulating not only snakes’ natural foraging and combat behaviors but also the evolutionary characteristics of genetic algorithms. For handling noisy trajectory data, Kalman filtering is applied to denoise measured information, laying a reliable foundation for subsequent parameter identification. The method utilizes segmented trajectory data of high-spin projectiles across different speed stages for analysis. Comparative experiments with the traditional SO algorithm and other optimized variants demonstrate that the proposed approach reduces identification errors by 49%, significantly outperforming conventional methods in accuracy. Further validation with full trajectory measured data shows that when the identified aerodynamic parameters are substituted into ballistic equations, the deviation between calculated and actual impact point coordinates is minimal, confirming their effectiveness. Notably, the improved algorithm does not rely on precise initial parameter settings, enhancing its adaptability in practical scenarios. In summary, it provides a robust solution for accurately identifying projectile aerodynamic parameters and holds promises for engineering applications.
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Authors and Affiliations

Baolu Yang
1
ORCID: ORCID
Liangming Wang
1
Jian Fu
1
  1. College of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
15 Aerodynamic Performance Optimization of a Vertical-Axis Wind Turbine Using Blade–Spoke Connection and Pitch Angle via the Taguchi Method
Himmet Erdi Tanürün
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e156796 | DOI: 10.24425/bpasts.2025.156796
Keywords: analysis of variance (ANOVA) computational fluid dynamics (CFD) confirmation test power coefficient (CP) wind energy
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Abstract

In this study, the effect of various parameters on the power coefficient (CP) performance of a vertical axis wind turbine (VAWT) was optimized using the Taguchi method. The optimization was conducted with the Taguchi method, employing three control factors: blade-spoke connection (BSC), turbine blade pitch angle (β) and turbine blade pitch direction (φ). Subsequently, the Analysis of Variance (ANOVA) method was employed to determine the contribution ratio of each control factor. Regression Analysis (RA) was applied to develop an empirical equation predicting the CP of the VAWT, incorporating the control factors. The results indicated an optimal parameter configuration of BSC=0.5c, β=2°, and φ= (-), which maximizes the system's performance. The performance of the optimal model was observed to exceed that of the conventional VAWT (B1) by a 5.82%. Using the ANOVA method, the contribution of parameters on the CP performance of the VAWT was ranked as follows: φ > BSC > β. The φ parameter has the most significant effect at 82.07%, whereas the β parameter with the least effect of 1.17%. Moreover, the predictive accuracy of the developed regression model was validated, yielding R² values of 0.9221 for the training data and 0.9908 for the test data.
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Authors and Affiliations

Himmet Erdi Tanürün
16 Seasonal and Predictive Analysis of Transport Fleet Availability and Reliability Using Long-Term Operational Data
Patrycja Guzanek , Anna Borucka
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e155894 | DOI: 10.24425/bpasts.2025.155894
Keywords: fleet availability reliability modelling seasonal effects predictive maintenance transport logistics regression analysis
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Abstract

This study introduces a novel empirical approach to analyzing seasonal variations in the availability and reliability of a transport vehicle fleet. While previous research has examined fleet reliability, few studies have integrated long-term operational data with complementary technical indicators and statistical modeling of seasonality. Using three key metrics - Fleet Availability Rate (FAR), Mean Time Between Failures (MTBF), and Mean Time to Repair (MTTR) - data from ten distribution vehicles operating over three years (2022–2024) were analyzed to identify recurring seasonal patterns. A linear regression model with seasonal dummy variables was applied to quantify the impact of weather conditions and operational intensity on vehicle availability. The results reveal a clear seasonal cycle: the lowest availability and highest failure rates occur between February and May, while summer and early autumn show near-optimal performance. The model demonstrated statistically significant differences between quarters and indicated a gradual long-term improvement in FAR. This study introduces a novel analytical and predictive framework that combines three reliability indicators with long-term operational data and regression-based seasonal modeling. The approach enables not only the identification of seasonal effects but also the prediction of fleet availability trends to support data-driven maintenance planning. These findings support more accurate forecasting of fleet availability and provide actionable guidance for optimizing maintenance schedules, resource allocation, and downtime risk management in transport operations. Overall, the results demonstrate how integrating operational data with seasonal regression models can improve predictive decision-making and optimize transport fleet reliability.
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Authors and Affiliations

Patrycja Guzanek
Anna Borucka
ORCID: ORCID
17 Decibel Scale Sensitivity in Analyses of Environmental Acoustic Risks
Wojciech Batko , Leszek Radziszewski , Andrzej Bąkowski
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e157065 | DOI: 10.24425/bpasts.2025.157065
Keywords: decibbel scale Weber-Fechner law enviromental pollution modeling
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Abstract

The article presents research on the applicability of the psychoacoustic Weber–Fechner law and its constancy across the entire decibel scale. The authors sought to resolve the stated problem based on an assessment of the sensitivity of the decibel scale. Different results were obtained depending on the rule adopted for estimating this characteristic. In the first case, operations of Euclidean algebra were used. In the second case, operations of decibel algebra derived from the psychoacoustic Weber–Fechner law were applied. It was shown that there is no connection between the decibel scale and the conditions of its perception y humans when modelling the examined relationship using Euclidean algebra operations. An acceptable interpretation of the sensitivity of the decibel scale was obtained when it was estimated using the relations of decibel algebra, whose computational relations are consistent with the conditions of human perception of acoustic disturbances. The obtained research results emphasise the key role of decibel algebra in computational procedures used to identify environmental acoustic hazards. They draw attention to the need for broader verification of existing procedures for controlling environmental acoustic hazards, in which there is currently a dualism in modelling identified acoustic threats.
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Authors and Affiliations

Wojciech Batko
ORCID: ORCID
Leszek Radziszewski
ORCID: ORCID
Andrzej Bąkowski
18 Silane-based injection methods for moisture protection in ceramic bricks
Natalia Szemiot-Jankowska , Anna Hoła
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 1 | e157095 | DOI: 10.24425/bpasts.2025.157095
Keywords: protection against moisture ceramic brick saline-based injection cream injection methods preliminary tests
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Abstract

Proper understanding of the mechanisms that lead to excessive moisture, as well as the development of effective methods for cutting off the flow of moisture to walls, is crucial for maintaining the durability and aesthetics of brick buildings, including historical ones. This issue is important in the context of protecting material cultural heritage and is consistent with the goals of sustainable development. The article presents the results of preliminary tests of the effectiveness of the protection against moisture of ceramic bricks, which was made using an injection method and a silane-based injection cream. Two injection methods were used: pressure and gravity, and the injections were performed in bricks with three levels of moisture: a permissible moisture content (3%), a moderate moisture content (7%), and a high moisture content (11%). The mass moisture content was determined using the gravimetric method, the spread of the injection agent in the brick was examined using the drop method and scanning electron microscopy, and the chemical composition of the bricks and injection cream was analyzed using X-ray fluorescence. The results of the tests showed that in the case of the analyzed samples, the most effective method was gravity injection applied at the permissible moisture content, while the least effective was gravity injection applied at a high moisture content of the bricks. The biggest difference in effectiveness between the injection methods was observed in high moisture content samples, where pressure injection proved to be significantly more effective. Confirmation of the results obtained requires further research.
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Authors and Affiliations

Natalia Szemiot-Jankowska
1
ORCID: ORCID
Anna Hoła
1
  1. Department of Materials Engineering and Construction Processes, Wrocław University of Science and Technology,Wybrzeze Wyspianskiego 27, Wrocław, Poland
19 Compatibility Charts of BRB-VD Combined Systems for RC Frames in Ultra-high Seismic Intensity Zones
Shuwei Lan , Yu Liu , Xiang Lan , Kechuang Wu
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 157319 | DOI: 10.24425/bpasts.2026.157319
Keywords: combined seismic energy dissipation buckling-restrained braces viscous dampers performance-based seismicdesign damper compatibility the K-ξa relationship charts
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Abstract

The combined seismic energy dissipation of BRB and VD in ultra-high seismic zones can exploit their respective advantages, resulting in a hybrid damping solution with superior performance and broad prospects. Although the potential of such combined damping systems in seismic design is widely acknowledged, the absence of a clear methodology for coordinating their distinct mechanisms of stiffness and damping remains a critical obstacle hindering their efficient application. To solve the compatibility problem between these two damping technologies, a series of computational analyses on reinforced concrete frame structures equipped with BRB-VD combined systems in ultra-high seismic zones is carried out. Key parameters, including the nominal lateral stiffness ratio K of BRBs and the additional damping ratio ξa provided by VD, are determined. Furthermore, the K-ξa relationship charts illustrating the compatibility between the two dampers under different seismic design groups in ultrahigh seismic zones are obtained, which can avoid the inconvenience caused by multiple iterations based on the response spectrum design method. Finally, the accuracy and practicability of the K-ξa relation charts for combined seismic energy dissipation design are verified by engineering examples, which provides a convenient manual calculation tool for structural engineers, and offers valuable references for global similar high seismic regions.
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Authors and Affiliations

Shuwei Lan
Yu Liu
Xiang Lan
Kechuang Wu
20 A Hierarchical Process Model Discovery Algorithm for CRS Systems
Andrzej Stroiński , Dariusz Dwornikowski , Anna Kobusińska , Jerzy Brzeziński
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 155043 | DOI: 10.24425/bpasts.2025.155043
Keywords: process mining data discovery process modelling distributed systems CRS systems
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Abstract

An increasing number of distributed systems are currently being developed according to the REST paradigm, supporting a diverse range of services and applications. However, analyzing potential errors and deviations in their operation has become progressively more difficult due to both the scale of processed data and the proliferation of available services. In this context, process mining offers a valuable approach. By analyzing event logs collected from such systems, it is possible to derive process models that represent application behavior in distributed environments. These models support the identification and remediation of errors as well as the optimization of system performance. This article introduces a mechanism for representing process models of Communication Resource Systems (CRS) developed within the RESTparadigm using process algebra. In addition, we propose an algorithm for discovering such models, enabling the identification of both local processes executed within individual services and the interactions that occur between them.
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Authors and Affiliations

Andrzej Stroiński
Dariusz Dwornikowski
Anna Kobusińska
Jerzy Brzeziński
21 Analysis of the Sensor Architecture for a Level 3 Autonomy System in Tracked Military Vehicles
Sebastian Jakubowski , Jakub Wiech
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 157321 | DOI: 10.24425/bpasts.2026.157321
Keywords: sensor architecture autonomous tracked vehicle self-propelled mortar
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Abstract

The article presents an analysis of the sensor system architecture designed for third-level autonomy in full-scale tracked platforms intended for military applications. In particular, it focuses on the use of advanced data fusion, enabling the integration of information from heterogeneous sensors, such as LiDARs, cameras, ToF (Time-of-Flight) sensors, inertial measurement units (IMUs), radars, and vehicle onboard systems. This configuration ensures a high degree of environmental perception accuracy and reliability in decision-making, which is crucial under the dynamic and demanding terrain conditions typical of combat operations. It also enhances situational awareness. Key aspects of designing the sensory system are discussed in detail, including the optimal selection of sensors, their placement on the tracked vehicle, and the implementation of real-time data fusion algorithms. The analysis covers the evaluation of these technologies in terms of environmental mapping accuracy, operational reliability, and adaptability under varying operational conditions. The research results indicate that an appropriate sensor architecture, supported by advanced data processing methods, significantly improves the effectiveness of condition-based autonomous control and the vehicle’s ability to adapt to the specific requirements of combat missions. The conclusions drawn from the study provide valuable guidance in designing modern military vehicles that utilize state-of-the-art sensing technologies and autonomous algorithms.
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Authors and Affiliations

Sebastian Jakubowski
Jakub Wiech
22 Modal Analyses of Non-Uniform Axially Functionally Graded Euler-Bernoulli Beams
Esra Zeynep Sensoy , Tarik Baran
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 157320 | DOI: 10.24425/bpasts.2026.157320
Keywords: Haar wavelet method functionally graded material functionally graded beam non-uniform axially functionally graded beam free vibration analysis
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Abstract

The dynamic response of functionally graded beams is of great importance in modern engineering applications where structural elements often exhibit material inhomogeneity and geometric non-uniformity. This study investigates flexural free vibrations of axially functionally graded Euler-Bernoulli beams with non-uniform cross-sections, where both geometric dimensions and material properties vary along the beam axis. The governing equations of motion were discretized and solved using the Haar wavelet method, which provides an efficient numerical scheme. Four classical boundary conditions; clampedfree, pinned-pinned, clamped-pinned, and clamped-clamped were analyzed to demonstrate the versatility of the approach. The accuracy of the method was verified by comparison with benchmark solutions available in the literature. Extended case studies were then performed for tapered and cone-shaped beams with linearly varying depth or width considering axially functionally graded material. The results demonstrate that variations in axial cross-sectional geometry have a greater impact on natural frequencies and mode shapes than material gradation. This study revisits the Haar wavelet method and extends its application to conditions that were previously unstudied, such as different functionally graded material models in tapered and cone configurations. The validated results are in good agreement with existing literature. Finally, detailed graphs and tables present the results obtained for previously uninvestigated cases.
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Authors and Affiliations

Esra Zeynep Sensoy
Tarik Baran
23 The study on the effect of blade guide strip on aerodynamic performance of horizontal axis wind turbine
Guowen Li , Haotian Song , Xinghui Wu , Xinhua Sun
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 157322 | DOI: 10.24425/bpasts.2026.157322
Keywords: guide strip wind turbine wind tunnel test lift-drag conversion
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Abstract

This paper mainly studies the influence of adhering hidden movable airflow guide strips to the surface of horizontalaxis wind turbine blades on the aerodynamic performance of the blades. The experimental data suggest that the guide strip changes the flow direction of the airflow. A reverse force will be generated in the opposite direction of the airflow outflow, i.e., the blade guide strip's resistance and the airflow's flow distance on the blade surface will be increased. The lift of the blade will be increased with a low starting wind speed and a significant wind energy utilization effect. The research results show that the guide strip structure can increase the lift coefficient of the blade by 9.1% under the condition of a small Angle of attack. When the wind speed reaches 8 m/s, the power coefficient increases by 14.1% and the starting wind speed decreases by 0.5 m/s. However, the negative resistance of the guide strip was increased at high incoming flow speeds. At this time, the guide strip was adopted to level the actuator and placed on the blade's surface. The experimental results show that when the guide strip is retracted, the output power of the wind turbine is the same as that of the prototype blade.Therefore, the guide strip blades with retraction and extension functions enhance the low-speed performance of the wind turbine while maintaining its high-speed performance.
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Authors and Affiliations

Guowen Li
Haotian Song
Xinghui Wu
Xinhua Sun
24 Optimal collision-free Cartesian trajectory planning for a free-floating space robot with non-zero linear and angular momentum
Tomasz Rybus
Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 157323 | DOI: 10.24425/bpasts.2026.157323
Keywords: free floating manipulator optimal trajectory planning obstacle avoidance space robotics
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Abstract

An unmanned chaser satellite equipped with a robotic manipulator can be employed for active debris removal and inorbit servicing missions. It is often assumed that the chaser satellite's control system is switched off during the capture operation performed with the manipulator. However, due to the limited accuracy of the chaser’s control system, which relies on thrusters for the approach phase, it may not be possible to obtain zero relative velocity of the chaser with respect to the target satellite. Moreover, in the tangent capture scenario, the chaser satellite is intentionally accelerated to a specific linear velocity before initiating the capture operation. This paper presents an optimal trajectory planning method applicable to a manipulator mounted on a free-floating satellite with non-zero initial velocity and non-zero but constant linear and angular momentum. The trajectory of the manipulator’s end-effector is parameterized in the Cartesian space using an 8th-order polynomial. The trajectory planning task is formulated as a constrained nonlinear optimization problem and solved using an interior-point algorithm. Constraints include joint position limits and collision avoidance with spherical obstacles. Two objective functions are considered: minimizing the trajectory length and minimizing the attitude changes of the chaser satellite. The proposed approach is validated through numerical simulations conducted using parameters from a prototype of the 7-DoF WMS 1 Lemur space manipulator. Trajectories obtained with the proposed approach are compared to two non-optimal trajectories: a straight-line trajectory and a collision-free trajectory obtained with the Artificial Potential Field method.
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Authors and Affiliations

Tomasz Rybus
ORCID: ORCID

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