Applied sciences

Bulletin of the Polish Academy of Sciences Technical Sciences

Description

The Bulletin of the Polish Academy of Sciences Technical Sciences is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred:

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 2023:	1.2
5 Year Impact Factor 2022:	1.1
CiteScore 2023:	2.8
SCImago Journal Rank (SJR) 2023:	0.282
Source Normalized Impact per Paper (SNIP) 2023:	0.573
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

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

Biomedical Engineering and Biotechnology

D. Pijanowska, 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 A. Lamęcki, 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 Enhancing Mobile Eye-Tracking in Extreme Urban Lighting Conditions

Marta Rusnak , Zofia Koszewicz , Franciszek Hackemer , Izabela Garaszczuk , Andrew T. Duchowski , Rafał Karnicki

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e152709 | DOI: 10.24425/bpasts.2024.152709

Keywords: outdoor eye-tracking smart city data quality calibration sunlight

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Abstract

One of the methods for understanding residents' needs and socially improving urban spaces in terms of transportation, safety, landscape protection, and managing tourist traffic load is eye-tracking (ET). Researchers using mobile ET for outdoor studies face significant challenges, particularly due to sunlight affecting data quality. Existing solutions often overlook participant comfort. This article introduces a novel accessory designed for extreme lighting conditions, such as bright days, sunsets, and snowy or water-filled environments. The goal is to eliminate disruptions caused by uncontrolled sunlight on participants' eyes and enables studies in urban environments. A custom sun shield, designed for ETs based on spectacle frames, prioritizes both physical and psychological comfort. The lightweight shield is easy to install, minimally restricts the field of view, and does not interfere with eye-tracking components. It is cost-effective and suitable for DIY 3D printing. Control studies and field research confirmed its effectiveness, with feedback from over 100 users improving the final design. The shield enhances eye-tracking research credibility in sunny conditions, supports efficient calibration, and improves participant recruitment and well-being. Jakość danych znacząco wzrosła co obrazuje porównanie danych dotyczących sposobu detekcji źrenicy. Thanks to this solution, it will be possible to conduct research aimed at better understanding the behavior of city users, while ensuring their comfort and safety. It will also be possible to conduct research within the framework of so-called living labs. Importantly, studies show that the approach to designing subsequent mobile ETs based on IR should undergo significant modification.

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Authors and Affiliations

Marta Rusnak

Zofia Koszewicz

Franciszek Hackemer

Izabela Garaszczuk

Andrew T. Duchowski

Rafał Karnicki

2 Slip Compensation Technique In Five-Phase Induction Motors Drive System

Krzysztof Blecharz , Roland Ryndzionek , Paul Gondran , Imad Merzouk

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153223 | DOI: 10.24425/bpasts.2025.153223

Keywords: five-phase induction motor multi-phase motor open-loop control slip compensation scalar control

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Abstract

The article presents a slip compensation method for traditional scalar (V/f) control of a five-phase induction motor. The proposed control method uses the possibility of injecting the third harmonic of voltage to increase the motor’s electromagnetic torque. The solution is characterized by both the simplicity of scalar control and improved speed control efficiency. The paper presents the PLECS simulation results and describes the laboratory tests that were conducted. The several scenarios were performed with dedicated and self developed algorithm in a laboratory stand using a 5-phase induction motor.

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Authors and Affiliations

Krzysztof Blecharz

e-mail:

ORCID:

Roland Ryndzionek

e-mail:

ORCID:

Paul Gondran

Imad Merzouk

3 Experimental Studies on Reducing Permanent Magnet Losses Through Segmentation in a Fractional Slot PMSM Motor with High Power Density

Tomasz Wolnik , Tomasz Jarek , Jan Mikoś , Vitezslav Styskala

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153225 | DOI: 10.24425/bpasts.2025.153225

Keywords: eddy-current losses segmentation of permanent magnets high power density motors

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Authors and Affiliations

Tomasz Wolnik

e-mail:

ORCID:

Tomasz Jarek

e-mail:

ORCID:

Jan Mikoś

Vitezslav Styskala

4 Multilevel voltage source inverter with coupled reactors using coarsely quantized pulse amplitude modulation

Krzysztof Jakub Szwarc , Artur Cichowski , Paweł Szczepankowski , Janusz Nieznański , Ryszard Strzelecki

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | 153227 | DOI: 10.24425/bpasts.2025.153227

Keywords: multi-level inverter pulse amplitude modulation coupled reactors multi-pulse voltage source inverter

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Abstract

The paper discusses a multilevel voltage source inverter with coupled reactors (MVSI-CR). The output voltage is generated using the novel coarsely quantized pulse amplitude modulation (CQ-PAM). The AC voltage synthesis is realized by selecting and applying an appropriate collection of voltage vectors from the space-vector diagram. Integrating classical two-level inverters allows achieving modularity of the solution. The main advantage of the proposed approach is a very low switching-to-fundamental frequency ratio and a multistep quasisinusoidal output voltage. The paper includes a theoretical analysis, simulations, and laboratory test results.

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Authors and Affiliations

Krzysztof Jakub Szwarc

Artur Cichowski

e-mail:

ORCID:

Paweł Szczepankowski

e-mail:

ORCID:

Janusz Nieznański

Ryszard Strzelecki

e-mail:

ORCID:

5 Study on Properties of Multipole Switched Reluctance Motor Designed for Multichannel Operation – Single Channel Operation Analysis

Mariusz Korkosz , Piotr Bogusz , Jan Prokop , Piotr Zasowski

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153428 | DOI: 10.24425/bpasts.2025.153428

Keywords: multi-channel spectrogram switched reluctance motor critical drive increased redundancy drive single channel operation

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Abstract

The following paper deals with the multipole design of the switched reluctance motor (SRM). The design is intended to facilitate the four-channel operation of the motor. Due to multipole design of the rotor and multichannel operation abilities, there are numerous possible configurations for powering the poles in each phase. Analysis of selected such configurations was carried out, including multichannel (MC) operating conditions (e.g. single-channel operation (SCO)). A mathematical model of three-phase MC SRM is presented. The static electromagnetic torque characteristics were obtained together with the self- and mutual inductance characteristics. Selected laboratory test results are presented in the paper.

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Authors and Affiliations

Mariusz Korkosz

e-mail:

ORCID:

Piotr Bogusz

Jan Prokop

Piotr Zasowski

6 Analysis of the impact of the method of manufacturing the rotor on the parameters of an ACIPM machine

Mariusz Korkosz , Adrian Młot , Elżbieta Sztajmec , Karol Ryłło

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153433 | DOI: 10.24425/bpasts.2025.153433

Keywords: anisotropy cogging torque IPM motor electrical steel sheet torque ripple reduction

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Abstract

This article presents the technological problem related to the production of rotor with internal permanent magnet. Most often, the magnetic circuits of such rotors used in alternating current synchronous motors (AC IPM) are made of isotropic magnetic sheets. At this point, it should be noted that it is often not taken into account that each isotropic magnetic sheet exhibitssome anisotropy. This significantly affects the operational parameters of the brushless permanent magnet (PM) motor such as a cogging torque, electromagnetic torque ripples and an increase in induced voltage harmonics. To illustrate how important it is to properly design the rotor core, two rotors of the IPM motor were analysed in this work. In the first rotor solution, the minimisation of the anisotropy of the magnetic sheet was not taken into account, and the skew of the magnets was not used. In the second case of the IPM motor, the problem of anisotropy of the rotor magnetic circuit was minimised and an additional skew of the PMs was used. The obtained measurements and calculations of selected useful parameters of both rotor designs were compared with each other. Importantly, the conclusions and comments are extremely important for designers, assemblers and manufacturers of electrical machine components.

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Authors and Affiliations

Mariusz Korkosz

e-mail:

ORCID:

Adrian Młot

e-mail:

ORCID:

Elżbieta Sztajmec

Karol Ryłło

7 Modeling the responsive structures under external forces using an evolutionary algorithm

Szymon Jankowski , Waldemar Bober

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153432 | DOI: 10.24425/bpasts.2025.153432

Keywords: responsive architecture for urban planning shape changing structures morphing urban structures smart city structures evolutionary algorithm structure behavior modeling

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Abstract

The design of responsive structures has evolved significantly, establishing itself as an interdisciplinary field characterized by a fully customized ideation process. To streamline and unify this process, a novel method for modeling the behavior of rod-like responsive structures using an evolutionary algorithm is introduced. The proposed mathematical framework leverages key geometric and physic parameters to control the generative process, enabling adaptability and fluidity in form development. By employing an evolutionary algorithm, the method offers an alternative to conventional rigid and repetitive morphing models, providing flexibility and innovation in responsive design outcomes. The developed model supports independent learning and fosters originality in solutions at both architectural and urban scales. Moreover, the presented methodology serves as the foundation upon which the authors developed the model, enabling its application across a wide spectrum of responsive structures for users. This paper addresses challenges in spatial modeling, behavioral algorithms, and the implementation of responsive architecture, presenting the author’s innovative model for rod-like responsive structures alongside performance analysis. The methodology demonstrates promising results in terms of adaptability and efficiency, with potential for further refinement to enhance speed and output quality. Research also describes challenges and risks for further development of responsive models implementation.

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Authors and Affiliations

Szymon Jankowski

Waldemar Bober

8 Three-Axis Forces and Torque Sensor

Paweł Młotek , Piotr Mynarek , Marcin Kowol

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153437 | DOI: 10.24425/bpasts.2025.153437

Keywords: three-axis force and torque sensor optical measurement of force and torque STM microcontroller structural analysis

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Abstract

This paper describes research on a prototype of a multi-axis force and torque sensor dedicated to the support system of a telescopic camera crane arm. Based on studies conducted on an actual telescopic camera crane arm., the requirements that the sensor must meet to enable precise control of the drives in two working axes of the telescopic camera crane arm were defined. In the developed sensor, a method for measuring forces and torques using an optical displacement sensor was proposed. A simplified sensor prototype was made to verify the assumptions, and measurement tests were carried out. Additionally, the paper presents a CAD model of the sensor using an elastic pin, based on which a numerical model was developed, and calculations of displacements and mechanical stresses were performed.

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Authors and Affiliations

Paweł Młotek

Piotr Mynarek

Marcin Kowol

e-mail:

ORCID:

9 Bending behaviour of thin-walled perforated channel beams with modified cross sectional shape – Part 2: analytical calculations and FEM

Paweł Jasion , Aleksandra M. Pawlak , Piotr Paczos , Michał Plust , Marcin Rodak

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153435 | DOI: 10.24425/bpasts.2025.153435

Keywords: thin-walled channel beams web perforations four-point bending structural stability bucklinganalysis

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Abstract

This article is the second part of a comprehensive research program investigating the structural performance of thinwalled channels with modified cross-sectional geometries. The study involved testing six beams, three of which featured perforated webs, while the other three had flat, solid webs. The beams were subjected to four-point bending tests to evaluate their load-bearing capacity. The first part of the research presented the results of experimental tests and finite strip analysis. This article will focus on finite element analyses and analytical calculations conducted in accordance with Eurocode 3 guidelines and the principle of minimizing potential energy. The study provides several significant contributions: it integrates experimental, numerical, and theoretical methods to deliver a thorough evaluation of beam performance. The finite element method (FEM) simulations offer precise modeling of complex stress and strain states, while analytical calculations supply a solid theoretical foundation for interpreting structural behavior. The research demonstrates that web perforation, while reducing critical and maximum forces, also results in considerable weight savings, enhancing material efficiency. Additionally, the division of the research into two articles ensures clarity and accessibility, with this second part dedicated to detailed FEM and analytical results, thereby facilitating both academic understanding and practical engineering applications.

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Authors and Affiliations

Paweł Jasion

e-mail:

ORCID:

Aleksandra M. Pawlak

e-mail:

ORCID:

Piotr Paczos

e-mail:

ORCID:

Michał Plust

e-mail:

ORCID:

Marcin Rodak

10 Study and Design of a Coaxial Magnetic Gear with a High Torque Density in Telescopic Camera Cranes

Piotr Warmuzek , Janusz Kołodziej , Marcin Kowol

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154203 | DOI: 10.24425/bpasts.2025.154203

Keywords: telescopic camera cranes magnetic gear magnetic torque torque ripple radial forces

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Abstract

Magnetic gears are slowly becoming a natural alternative to mechanical gears. Providing contactless, frictionless, and low-noise torque conversion, they are finding applications in renewable energy sources and electric vehicles, among others. This paper presents a comprehensive theoretical analysis with numerical calculations of a magnetic gear (MG) design for novel applications in telescopic camera cranes. Based on numerical simulations of selected MG variants, a potential transducer configuration was chosen that would meet the requirements of the drive transmission system - supporting the movement of the telescopic camera crane arm.

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Authors and Affiliations

Piotr Warmuzek

Janusz Kołodziej

e-mail:

ORCID:

Marcin Kowol

e-mail:

ORCID:

11 Numerical Simulation of Transient Start-up Characteristics in Pump-Driven Two-Phase Flow Systems

Nianyong Zhou , Jing Li , Jixiang Liu , Kaiming Liu , Feifei Wang , Lianghui Liu

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154202 | DOI: 10.24425/bpasts.2025.154202

Keywords: pump two-phase flow heat transfer evaporative cold plate startup characteristic

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Abstract

The pump-driven two-phase flow system is widely used in electronic cooling due to its high heat transfer efficiency and stable temperature control. However, transient startup behaviors, crucial for reliability in dynamic thermal environments, remain poorly understood. This study addresses this gap by developing a simulation model using AMESim software with R134a as the working fluid, investigating the effects of heat load, pump speed, and cooling water temperature on startup dynamics. Results reveal three distinct startup types: Type I rising startup, Type II rising startup, and Type I falling startup. As the heat load increases from 2 kW to 5 kW, the system transitions from Type I to Type II, with the cold plate wall temperature decreasing by up to 27%. At 2 kW and 5 kW, the system exhibits Type I upward and Type II upward startup behaviors, respectively. Type II startup demonstrates reduced overshoot, enabling a quicker approach to quasi-steady state. At 2 kW, the system exhibits both single-phase and two-phase heat transfer, with the latter lowering the temperature by 2.26℃. Excessive subcooling can induce temperature oscillations within the evaporator. At a pump speed of 200 r/min, Type I upward startup is observed; however, increased speeds result in wall temperature overshoot. Furthermore, raising the cooling medium temperature from 10℃ to 40℃ elevates the evaporator wall temperature by 51.67%. By integrating quantitative metrics for overshoot, response time, and subcooling effects, this work provides actionable insights for optimizing pump-driven two-phase systems in high-heat-flux electronic cooling applications.

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Authors and Affiliations

Nianyong Zhou

e-mail:

ORCID:

Jing Li

Jixiang Liu

Kaiming Liu

Feifei Wang

Lianghui Liu

12 Numerical simulation method of fork-flow condenser and the influence of fin structure characteristics

Kaiming Liu , Nianyong Zhou , Lianghui Liu , Benshi Han , Jing Li , Guanghua Tang , Jixiang Liu , Feifei Wang

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154273 | DOI: 10.24425/bpasts.2025.154273

Keywords: condenser multiphase flow priodic iteration numerical simulation heat transfer characteristics

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Abstract

Many researchers have investigated numerical simulation methods for two-phase flow in condensers. Still, challenges persist due to these models' large size, complex structure, and multiphase flow fields. To address these issues, this paper employs a periodic iterative numerical simulation approach for ultra-long condensers, validating the method through experiments and advancing the numerical simulation technology for such models. The study emphasises the impact of structural changes on the refrigerant and air sides. Results indicate that the most minor error occurs when the number of iterations in the two-phase zone does not exceed three. Increasing the total number of refrigerant channels from 10 to 18 enhances heat transfer by 17.7% and condensation capacity by 10.6%. However, further increases in channel numbers lead to a significant rise in pressure drop, deteriorating heat transfer performance. The heat transfer and condensation capacity improve with the height-to-width ratio of the refrigerant channel, reaching optimal performance when the ratio is close to 1. Additionally, increasing the aspect ratio on the air side will improve the heat transfer and condensation rate of the condenser. However, when the aspect ratio reaches 4.53, further increases will lead to a decrease in the heat transfer coefficient and an increase in pressure drop.

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Authors and Affiliations

Kaiming Liu

Nianyong Zhou

e-mail:

ORCID:

Lianghui Liu

Benshi Han

Jing Li

Guanghua Tang

Jixiang Liu

Feifei Wang

13 Signed Networks with Laplacian Feedback: Observability and Minimal Sensor Problem

Vijayakumar S. Muni , Kallu Vetty Muhammed Rafeek , Gudala Janardhana Reddy , Deena Sunil Sharanappa

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154061 | DOI: 10.24425/bpasts.2025.154061

Keywords: multi-agent systems observability signed graph

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Abstract

In many multi-agent networks that evolve according to specific dynamical rules, our direct access is often limited to only a small subset of agents, known as “sensors.” The remaining agents in the network, whose states are entirely inaccessible, are referred to as “actuators.” If it is possible to retrieve the complete states of the actuators from the knowledge of the sensors’ states, the network is said to be “sensor– actuator observable”; otherwise, it is deemed unobservable. This research explores the analysis of sensor–actuator observability property (i.e., observable or unobservable) in networks where agent communications encompass both cooperation and competition (i.e., signed networks). It is assumed that the network’s agents continuously update their states within R under the Laplacian protocol. We simplify the Kalman’s and the PBH rank criteria for evaluating sensor–actuator observability property into several verifiable algebraic tests, emphasizing the significance of the system matrices’ spectral properties. This property is also examined from the perspective of the network’s graph topology. Sensor– actuator observability property is significantly influenced by the nature of agent communications and is often differs between signed and unsigned networks. However, we demonstrate that for a structurally balanced signed network, with specific set of sensors, it’s sensor–actuator observability property aligns with that of its unsigned variant. We present a formula utilizing Laplacian spectral information to determine the minimum number of sensors for an ensured sensor–actuator observable network. Applying the formula to path and cycle networks, it is found that paths are observable with one sensor, and cycles require two for observability.

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Authors and Affiliations

Vijayakumar S. Muni

Kallu Vetty Muhammed Rafeek

Gudala Janardhana Reddy

Deena Sunil Sharanappa

14 A flying start method for sensorless induction machine-based electric drives

Daniel Wachowiak

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154206 | DOI: 10.24425/bpasts.2025.154206

Keywords: induction machine flying start speed observer sensorless drive DC injection

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Abstract

This paper presents an analysis of a proposed flying start method for sensorless electric drives based on an induction machine. The method introduces two stages. In the first stage, the rotor speed is estimated using the step response of the machine, which enables coarse estimation of the speed and direction of rotation, helping to reduce the initial slip. The second stage introduces an intermediate control system to facilitate the machine restart and assist the speed observer in converging. Simulation and experimental studies demonstrate that the method successfully restarts the machine with unknown initial rotor speed without exceeding the nominal current. The auxiliary control system fully excites a 5.5 kW machine within 300 ms during the flying start, after which it is possible to transition to the target control system.

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Authors and Affiliations

Daniel Wachowiak

e-mail:

ORCID:

15 Processing and analysis of trolleybus traction data using LINQ technology

Andrzej Wilk , Mikołaj Bartłomiejczyk , Jacek Skibicki , Leszek Jarzębowicz , Dariusz R. Karkosinski , Łukasz Hupka , Jan Hupka , Paweł Kaczmarek , Natalia Karkosinska-Brzozowska

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154144 | DOI: 10.24425/bpasts.2025.154144

Keywords: trolleybuses traction batteries exploatation and maintaining

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Abstract

The paper presents the processing and analysis of the recorded trolleybus data using the LINQ (Language Integrated Query) software technology. The trolleybus data acquisition system collects a huge amount of electromechanical data in real time during the vehicle operation. These data are used for the analysis in post-processing mode. In this paper, the data processing has been performed to assess the technical condition of trolleybus batteries. Selected standard query operators of the LINQ technology have been implemented in the Windows Presentation Foundation (WPF) application to process the data and to determine the charge and energy stored in the battery. The LINQ technology has been proven to be useful for analysing large amounts of data recorded from trolleybuses.

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Authors and Affiliations

Andrzej Wilk

e-mail:

ORCID:

Mikołaj Bartłomiejczyk

Jacek Skibicki

Leszek Jarzębowicz

Dariusz R. Karkosinski

Łukasz Hupka

Jan Hupka

Paweł Kaczmarek

Natalia Karkosinska-Brzozowska

16 A Markov Chain Model to Determine Optimal Maintenance Policy for Production Process

Mohammad Saber Fallah Nezhad , Mohammad Hossein Kargar Shouroki , Shahaboddin Kharazami

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154065 | DOI: 10.24425/bpasts.2025.154065

Keywords: discrete-time Markov chain maintenance policy optimum policy cost minimization

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Abstract

This paper considers an operating machine with deteriorating performance over time. Initially, functioning at 100% of its nominal capacity, the machine fails after a stochastic period, reducing its capacity to a proportion of the nominal level. In this degraded capacity state, three maintenance and repair policy options are available for evaluation. By modeling the system as a discrete-time Markov chain and analyzing the probability transition matrix between the system states, the costs associated with the loss of production, part replacement, and ongoing operation in each state can be quantified. The objective function representing the average cost per unit time of production is calculated to determine the optimal maintenance policy. Different policies are modeled by Markov chain and the average cost of each policy are obtained. The results demonstrate the applicability of the proposed methodology to evaluating different policies.

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Authors and Affiliations

Mohammad Saber Fallah Nezhad

Mohammad Hossein Kargar Shouroki

Shahaboddin Kharazami

17 EMF Signature Analysis in a Marine-Type Brushless Synchronous Generator for Online Fault Detection

Filip Kutt , Michał Michna , Grzegorz Kostro

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154207 | DOI: 10.24425/bpasts.2025.154207

Keywords: generator maintenance diagnostic marine ship

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Authors and Affiliations

Filip Kutt

e-mail:

ORCID:

Michał Michna

e-mail:

ORCID:

Grzegorz Kostro

e-mail:

ORCID:

18 Strain-controlled uniaxial fatigue of an AA2519 aluminum alloy sheet

Łukasz Pejkowski , Maciej Kotyk

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154271 | DOI: 10.24425/bpasts.2025.154271

Keywords: AA2519 aluminum alloy sheet metal fatigue life

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Abstract

This study provides a comprehensive investigationŁ of the uniaxial, strain-controlled fatigue behavior of an AA2519 aluminum-copper alloy. The alloy was characterized in the as-fabricated state. Three orientations relative to the rolling direction were used to determine the mechanical properties. The quasistatic strength and cyclic stress‒strain response of the AA2519 aluminum alloy for the examined cases were similar regardless of the rolling direction, although slight differences between them were noticeable. Similarly, the fatigue life was not strongly affected by the specimen orientation. The investigation also included fractographic analysis of the fracture surfaces, revealing differences between strain amplitude levels and specimen orientations. The experimental results obtained provide a good basis for engineering applications of the analyzed AA2519 alloy and offer a solid foundation for further research into the effect of heat treatment on the fatigue strength of the investigated alloy.

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Authors and Affiliations

Łukasz Pejkowski

Maciej Kotyk

19 Tribological properties of plasma sprayed NiAlAg-Ta-Cr₂O₃ composite lubrication coatings from room temperature to 750 C

Chengqi Yan , Xiaopeng Miao , Zhuying Jia , Fei Zhao , Yong Zhang

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154275 | DOI: 10.24425/bpasts.2025.154275

Keywords: lubricating coatings plasma spraying silver tantalate wide temperature range

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Abstract

With the rapid advances in science and technology, the core parts and techniques in tribo-systems rely on the solidlubricating materials at wide-temperature range for durability, especially for designing and producing materials with low friction coefficient and high wear resistance over a wide temperature ranges. In this paper, a series of NiAl-Ag-Ta-Cr₂O₃ composite coatings with different contents of Ta and Ag were deposited by plasma spraying, their tribological properties at RT-750 C under dry sliding conditions were investigated by a ball-on-disk tribometer. The friction products and compositions of worn surface at different temperature were investigated. The deposited NiAl-Ag-Ta-Cr₂O₃ composite coatings exhibited excellent wear resistance at RT (10^-7 mm³ /N m), while the friction coefficients lower than 0.5 at RT to 750 C. The contents of Ta and Ag decided mechanical properties of coatings, and greatly affected the tribological properties by creating an tribo-film (lubricant film and glaze layer). NiAl-10Ag-5Ta-20Cr₂O₃ coating shows better tribological properties over all temperature, while the wear rate reduces to 5 58×10^-6 mm³ /N m at 750 C and the friction coefficient reduces to 0.21 at 600 C. The excellent lubrication and wear resistance of composite coatings at high temperatures are mainly attributed to the Ag acted as lubrication phase, and the top surface of wear track was covered with a smooth glaze layer, which consisted of Ag, Ta₂O₅, Cr₂O₃ and AgTaO₃. In addition, the lubrication mechanism of silver tantalate was also briefly discussed.

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Authors and Affiliations

Chengqi Yan

Xiaopeng Miao

Zhuying Jia

Fei Zhao

Yong Zhang

20 Feasibility Study on In-Situ Heat Injection of Tongchuan Oil Shale and Tar-Rich Coal Based on TG-DTG

Heping Yan , Xiurong Wu , Qiang Li , Yinghui Fang , Qingfeng Bu

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154274 | DOI: 10.24425/bpasts.2025.154274

Keywords: in-situ conversion tongchuan oil shale TG-DTG pyrolysis characteristic

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Abstract

In-situ thermal injection is an effective development method for low-value unconventional resources. The non-isothermal pyrolysis characteristics of Tongchuan oil shale and tar-rich coal were investigated by TG-DTG extrapolation. In addition, the pyrolyzed shale oil was analyzed. It results shows that the pyrolysis of oil shale and tar-rich coal can be divided into three stages. The pyrolysis temperature intervals of the both can be consistent. Compared with the oil shale, ignition temperature of the mixed decreased by 2.3% and burnout temperature increased by 1.4%. The pyrolysis index increased by 40.3%, the pyrolysis stability increased by 66.7%, and the content of oxygenated compounds increased by 552.4%. The conversion of oxygenated compounds to phenolic compounds was inhibited at the 20°C/min heating rate. In the air, the excessively fast heating rate caused the tar to condense earlier and coking on the sample surface. The pyrolysis index of the mixed decreased from 3.2 to 1.8 times, while the pyrolysis stability increased by 6.7 times, respectively. The introduction of excessive oxygenated groups by the air increased the content of oxygenated compounds in the mixed by 485.44%. while the aromatic hydrocarbons decreased by 17.97%. It can be seen that the co-pyrolysis of oil shale and tar-rich coal can improve the ignition characteristics of oil shale. The co-pyrolysis of oil shale and tar-rich coal not only conforms to the distribution characteristics of the both, but also greatly cooperates with the topical chemical reaction method.

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Authors and Affiliations

Heping Yan

Xiurong Wu

Qiang Li

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Yinghui Fang

Qingfeng Bu

21 Energy Efficiency of Supercapacitors in Hybrid Energy Storage Systems

Mirosław Lewandowski , Marek Orzydłowski , Tadeusz Maciołek

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e153841 | DOI: 10.24425/bpasts.2025.153841

Keywords: supercapacitor storage system energy loss fractional calculus impedance model

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Abstract

The supercapacitor supports the main energy source of the hybrid electrical energy storage system. In short periods, it supplies additional energy or absorbs braking energy. The article deals with energy losses in supercapacitors used in such a pulsed mode of operation. Commonly used first-order RC capacitor impedance models are not a good basis for accurate calculation results of energy losses in supercapacitors. The article presents fractional-order supercapacitor impedance models based on the Cole-Cole relaxation equation. The following part presents the results of measurements of energy losses in real supercapacitors in comparison with simulation calculations using both of the above-mentioned supercapacitor impedance models. The article also discusses the problem of using the equivalent series resistance (ESR) values in RC impedance models, called AC ESR and DC ESR, specified by different supercapacitor manufacturers. It shows that the simulation results using the presented fractional impedance model are the closest to reality. The use of the other discussed models leads to even a several-fold underestimation of energy losses in supercapacitors used in electric energy storage systems.

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Authors and Affiliations

Mirosław Lewandowski

Marek Orzydłowski

Tadeusz Maciołek

22 Flower Pollination Algorithm Optimization Applied for Lyapunov-based Fuzzy Logic Speed Controller of a Complex Drive System

Grzegorz Kaczmarczyk , Radosław Stanisławski , Łukasz Knypiński , Danton Diego Ferreira , Marcin Kamiński

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154205 | DOI: 10.24425/bpasts.2025.154205

Keywords: flower pollination algorithm fuzzy logic controller two-mass system electric drives

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Abstract

With the current trends in manipulator design, plentiful examples of machines with flexible links and joints can be instantiated. Lighter construction that allows bending and torsion offers multitude of advantages, such as lower energy consumption and better operation safety when collision is possible in the working environment. However, precise control of applications with such mechanical constructions is very challenging. The state variables might be affected by torsional vibrations, and identification of controller parameters is more difficult, which makes the controller tuning complicated. Therefore, this work focuses on tackling the issues related to speed control of electric drives with sophisticated, and elastic couplings. The robustness against parameter uncertainty is provided through the use of a fuzzy logic system. The speed controller design process incorporates the selection of the rule base, designation of membership functions, as well as controller gain optimization using a nature-inspired technique - the Flower Pollination Algorithm (FPA). Increased damping of torsional vibrations, as well as decreased sensitivity to inertia changes is expected compared to other conventional control solutions, such as PI control. In this study both numerical and experimental studies are conducted.

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Authors and Affiliations

Grzegorz Kaczmarczyk

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Radosław Stanisławski

Łukasz Knypiński

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Danton Diego Ferreira

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ORCID:

Marcin Kamiński

23 Integrating AI-Driven DeepFake Generation with IoT Surveillance Systems: A Structured Framework for Synthetic Media Creation

Revathi Lavanya Baggam , Vatsavayi Valli Kumari

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154066 | DOI: 10.24425/bpasts.2025.154066

Keywords: artificial intelligence machine learning deep learning

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Abstract

The convergence of artificial intelligence (AI) and Internet of Things (IoT) technologies has revolutionized surveillance systems, enabling the collection and analysis of vast amounts of visual data. In this context, the emergence of Deep-Fake technology presents both opportunities and challenges for enhancing surveillance capabilities. This paper proposes a structured framework for integrating AI-driven DeepFake generation with IoT surveillance systems, aiming to create synthetic media for diverse applications such as training, testing, and augmenting surveillance datasets. The framework encompasses data acquisition, pre-processing, model training, and deployment stages, leveraging deep learning techniques to synthesize hyper-realistic images and videos. Key components include the utilization of convolutional neural networks (CNNs) for feature extraction, generative adversarial networks (GANs) for realistic media synthesis, and IoT sensors for realtime data collection. Ethical considerations regarding privacy, consent, and data security are carefully addressed throughout the framework. Experimental validation demonstrates the effectiveness of the proposed approach in generating synthetic media that closely resemble real-world surveillance footage. Overall, this framework represents a significant step towards leveraging AI-driven DeepFake technology to enhance thecapabilities of IoT surveillance systems while ensuring ethical and responsible deployment in practice. Subsequently, we employ a Deep Q Learning process for continuous updating and results processing within the structured framework.

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Authors and Affiliations

Revathi Lavanya Baggam

Vatsavayi Valli Kumari

24 Transient Analysis of Electrodynamic Forces in Low-voltage Compact Busbar

Michał Szulborski , Sebastian Łapczyński , Łukasz Kolimas , P Berowski , M. Owsiński

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154204 | DOI: 10.24425/bpasts.2025.154204

Keywords: electrodyamic forces transient analysis experimental tests FEA busbars

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Abstract

The paper concerns the effects of electrodynamic forces that act on the current paths of the industrial low-voltage busbar. This work is composed of experimental and simulation sections. In the experimental section, the short circuit tests were presented and the occurrence of electrodynamic forces has been shown visibly. The formation of electrodynamic forces in the current circuits of electrical energy distribution systems is related to the flow of high currents, mostly short circuit currents. To highlight those phenomena the detailed specification of parameters during tests was displayed. In the simulation section, the physical phenomenon of electrodynamic forces is captured by employing a detailed real-scale model of a commercial busbar. Therefore, the authors proposed the employment of FEA (Finite Element Analysis) to obtain values of electrodynamic forces acting on the current paths by executing the detailed 3D coupled simulation. The analysis of the results and aftermath effects of their interactions brought interesting conclusions that concerned the operation of such power distribution circuits under shortcircuit conditions.

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Authors and Affiliations

Michał Szulborski

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Sebastian Łapczyński

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Łukasz Kolimas

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P Berowski

M. Owsiński

25 Kronecker product-based solvers for higherorder finite element method Navier-Stokes simulations

Tomasz Służalec , Marcin Łoś , Mateusz Dobija , Maciej Paszynski

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154276 | DOI: 10.24425/bpasts.2025.154276

Keywords: partial differential equations finite element method Navier-Stokes equations variational splitting Petrov-Galerkin method Kronecker product solver

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Abstract

Transient time-dependent problems solved with higher-order finite element methods and time integration schemes sometimes encounter instabilities in time steps due to varying model parameters. This problem is commonly illustrated on a transient cavity flow modeled with Navier-Stokes equations, where for large Reynolds number, finite element discretizations Bu = f become unstable. The instability comes from the discrete inf-sup condition not fulfilled by the Galerkin method. To stabilize time steps, we employ a Petrov-Galerkin method B^T Wx = W^Tf with optimal test functions. However, this method commonly has two disadvantages. First, having a larger test space fixed, wemust compute the matrix of coefficients of the optimal test functions W on the fly, which requires solving a system of linear equations GW = B with proper Gram matrix G each time step for varying model parameters. Second, the matrix of coefficients of optimal test functions is dense, and thus, the cost of multiplying it to other matrices B^TW (which is needed) is high. To overcome these problems, we explore the Kronecker product structure of the matrix of coefficients of the optimal test functions G as well as of the matrices B resulting from the variational splitting of the time-integration scheme. Our solver can be successfully applied to the high Reynolds number Navier-Stokes equations.

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Authors and Affiliations

Tomasz Służalec

Marcin Łoś

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Mateusz Dobija

Maciej Paszynski

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26 Design and Implementation of Non-circular Gears Based on Target Transmission Ratio

Weizhen SONG , Yong HE

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154227 | DOI: 10.24425/bpasts.2025.154277

Keywords: non-circular gear target transmission ratio kinematic analysis tooth profile extraction equal arc length algorithm

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Abstract

Addressing the complexities inherent in current specific non-circular gear design, including the extensive computational demands involved in solving tooth profile feature points and the lack of a rigorous design and verification process, this study proposes a design method grounded in gear meshing theory. Specifically, the method focuses on achieving the target transmission ratio for non-circular gear. First, the pitch curve equation for the non-circular gear is computed. Secondly, an equal arc length algorithm is proposed to determine the polar diameter rotation angle corresponding to the same arc length per turn, generating a non-circular gear envelope diagram using the equal arc length enveloping method. Subsequently, an edge extraction algorithm is presented to obtain the tooth profile feature data. After obtaining tooth profile feature data, the 3D model of non-circular gears are generated. Then, the gear pair is virtually assembled, and the meshing process is analyzed using a motion simulation method. The results show that the tooth profile meshes well, and the angular velocity curve of the driven wheel is consistent with the target transmission ratio. Finally, the processed non-circular gear was inspected, and the results indicated that the error between produced non-circular gear and the theoretical tooth profile was within a reasonable range. This confirms the accuracy of the proposed method and provides a rigorous design and verification process for non-circular gears, which is beneficial for further analysis in manufacturing and other tasks. This method not only significantly reduces computation time but also simplifies the process of extracting tooth profile feature points, ensuring extraction accuracy.

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Authors and Affiliations

Weizhen SONG

Yong HE

27 Static analysis of a two-layer beam with a flexible interlayer connection

Katarzyna Misiurek , Monika Podwórna , Piotr Ruta , Olga Szyłko-Bigus , Rafał Idzikowski

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154278 | DOI: 10.24425/bpasts.2025.154278

Keywords: two-layer beam interlayer slip static analysis

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Abstract

The aim of this research is to develop an algorithm that allows for the analysis of the influence of interlayer connections on the static response of double-layer beams. Multilayer beams, due to the fact that their construction uses the advantages of different materials, are widely used in the construction industry. The critical element of these types of structures is the connection between layers. The stiffness of this connection can significantly affect the static response of the system, and therefore its strength. The Euler-Bernoulli model was used to describe the double-layer beams. In the paper, the compliance of normal displacements in multilayer and double-layer beams was considered based on the research of other authors. It was also assumed that the tangential interactions at the connection of layers were tangential forces that are proportional to the relative tangential displacement (slip) of these layers. This general approach eliminates the need for a broader analysis of the connection (its description and structure) with regards to the applied "connector" between the layers. Using equilibrium equations and the adopted assumptions, a system of displacement equations was derived. This system is formed by three coupled second- and fourth-order differential equations, the exact solution of which is a non-trivial mathematical problem. This system was solved using the finite sine and cosine Fourier transform. Although the algorithm presented in the paper was used to solve a specific set of equations that describe a simply supported beam, the formulas derived in the paper allow for solving beams with other support schemes. The Fourier transformation method, after appropriate modifications (changing the boundary conditions and, in some cases, changing the sine to cosine transformation and vice versa), can be used to solve beams that have other support conditions. In order to verify the correctness and effectiveness of the described method, two numerical examples were solved. In the first one, the influence of the variable value of the tangential stiffness of the connection on the values and distribution of internal forces (including the influence on the values of normal stresses) was analyzed. In the second example, calculations were performed for an example taken from literature, and the obtained results were compared with the results obtained by other authors. The analyzed examples confirmed the significant influence of the tangential stiffness of the layer connection on the static response of the system. Furthermore, they confirmed the correctness and high accuracy of the method that was used to solve the problem.

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Authors and Affiliations

Katarzyna Misiurek

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Monika Podwórna

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ORCID:

Piotr Ruta

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ORCID:

Olga Szyłko-Bigus

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ORCID:

Rafał Idzikowski

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28 Dynamics Analysis on Cavitation Flow Field of Centrifugal Pumps using Modal Order Reduction

Yancheng Zhang , Lei Zhang , Cong Wang , Tengjiao Sun , Z. Li , Dezhi Jiang

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154280 | DOI: 10.24425/bpasts.2025.154280

Keywords: centrifugal pump cavitation flow field modal, analysis dynamic modal decomposition

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Abstract

Throughout the operational lifecycle of centrifugal pumps, cavitation is an omnipresent phenomenon that frequently leads to cavitation erosion and a decline in hydraulic heads, leading to mechanical failures and substantial damages to the pump assembly. Although the cavitation phenomenon has been widely studied in existing literature, it is still a challenging task for reliable flow dynamics analysis of the centrifugal pumps using the modal order reduction technique. In this study, the modal decomposition and reconstruction of the flow field of a centrifugal pump with considering the cavitation are carried out. The dynamic modal decomposition (DMD) based on the singular value decomposition (SVD) is employed to explore the dynamic behavior of the cavitation flow field by reducing the modal order of the flow field. Then, the modal characteristics of the pump flow field are systematically analyzed. The results demonstrate that the DMD method can improve the accuracy of the order reduction model and reduce the modal reconstruction error, the reconstruction error loss is less than 5%, and the calculation efficiency is significantly enhanced to analyze the pump cavitation flow field. In addition, through comparing the calculation data between the finite element simulation and the DMD reconstructed flow field, it indicates the potential application of the DMD method in investigating the degradation of the flow field due to cavitation, which provides new perspective and solid technique support for centrifugal pump cavitation analysis.

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Authors and Affiliations

Yancheng Zhang

Lei Zhang

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ORCID:

Cong Wang

Tengjiao Sun

Z. Li

Dezhi Jiang

29 The Fractional, Multi Order, Reduced Model of the One Dimensional Heat Transfer Process

Krzysztof Oprzędkiewicz

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154282 | DOI: 10.24425/bpasts.2025.154282

Keywords: multi order fractional system heat transfer process multi order fractional state equation stability controllability observability

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Abstract

In the paper a new, fractional, reduced, multi order model of a one dimensional heat transfer process is addressed. The proposed model is the generalization of state space models using single fractional order. The use of various orders for each mode of state equation allows to better describe a behaviour of a thermal system. In addition, the analysis of controllability and observability allows to reduce the dimension of the model without loss of its accuracy. Such a model has not been proposed yet. Theoretical considerations are validated using experimental data obtained from the real laboratory system. Results of analysis supported by experiments show that the use of variouos orders together with eliminating of non controllable and non observable modes of the model allows to obtain the accurate and relatively low order model.

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Krzysztof Oprzędkiewicz

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30 On optimising the solution for evaluation of scientific quality in Polish higher education system using a 2D cutting problem representation

Dariusz Horla

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154283 | DOI: 10.24425/bpasts.2025.154283

Keywords: evaluation of scientific quality higher education 2D cutting optimalisation

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Abstract

This paper discusses the problem of optimising the solution to find the possibly best estimate of the value of C1 criterion in the evaluation process of scientific quality in higher education in Poland, which has been exercised by its author during the evaluation of Polish universities in 2022 as a vice dean for scientific evaluation and teaching quality at his faculty. The second edition of evaluation in Poland is expected to start in 2026 again, making this task an interesting problem, again. On the basis of the approach described in the paper, it was possible to ensure continuous monitoring and estimation of the effectiveness of the publication policy to make decisions along the way. An adopted strategy used a simple formulation of the problem, allowing one to obtain the close-to-optimal solution in a matter of seconds, in comparison with a tedious computational campaign to adopt, when presenting the precise value for C1 criterion, actually disabling not only the on-demand monitoring capacity, but also making alteration of the result in a close to online manner virtually impossible. The paper actually deploys a 2D cutting problem in strip tasks solver to mimic the steps to be taken to pursue with the scientific evaluation process.

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Dariusz Horla

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31 Estimation of CO₂emissions from vehicles using machine learning and multi-model investigation

Mükerrem Sinem Mungan , Orhan Arpa

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154287 | DOI: 10.24425/bpasts.2025.154287

Keywords: CO2 emissions machine learning CatBoostRegressor regression analysis environmental sustainability

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Abstract

This study presents a comprehensive analysis of the prediction of carbon dioxide emissions from vehicles using machine learning based regression models. Linear Regression, Lasso Regression, K-Nearest Neighbor Regression, Random Forest and CatBoostRegressor algorithms are systematically evaluated using a dataset of vehicle specifications and emissions data. Hyper-parameter optimization was performed using a grid search method and the performance of the models was measured using Mean Squared Error, Root Mean Squared Error, Mean Absolute Error and R-Squared metrics. CatBoostRegressor stood out for its high predictive accuracy, while Random Forest and K-Nearest Neighbor models also produced notable results, while linear models failed to model complex data relationships. Correlation analysis showed that engine displacement, number of cylinders and fuel consumption were strongly correlated (0.92-0.99) with carbon dioxide emissions. Comparison with the literature showed that the study was characterized by its multi-model approach, rigorous data pre-processing and systematic optimization. However, the geographical limitation of the dataset and the lack of dynamic variables such as driving conditions limit its generalizability. In the future, Explainable Artificial Intelligence methods and larger datasets may overcome these limitations. By highlighting the applicability of CatBoostRegressor, this study strengthens the contribution of machine learning to environmental sustainability policy and provides a methodological innovation to the literature.

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Authors and Affiliations

Mükerrem Sinem Mungan

Orhan Arpa

32 Usability of microstructural investigations of concrete-like composites; aggressive factors monitoring

Filip Chyliński , Lech Czarnecki , Thomas Mathia

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154284 | DOI: 10.24425/bpasts.2025.154284

Keywords: microstructure concrete like composites SEM concrete corrosion usability function

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Abstract

The microstructure of a material is a key factor in determining its properties and durability. This article highlights key findings from microstructural investigations of concrete-like composites, focusing on their practical applicability. A usability function and trends of its classification are proposed in order to demonstrate the potential of various microscopic techniques in addressing research questions within the field of building materials. In this part of the analysis, various investigations have focused on aggressive factors that affect the microstructures and might cause corrosion of concrete-like composites. The findings of this study highlight that the impact of corrosive agents on Portland cement composites cannot be comprehensively assessed without a detailed investigation of their microstructure. This underscores the pivotal role of microscopic techniques in the evaluation of concrete-based materials.. Furthermore, the significant progress is expected in the near future as image analysis becomes increasingly supported by Artificial Intelligence.

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Filip Chyliński

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Lech Czarnecki

Thomas Mathia

33 Pile-base resistance formation in natural-scale field conditions

Paweł Siemaszko

Bulletin of the Polish Academy of Sciences Technical Sciences | Early Access | e154720 | DOI: 10.24425/bpasts.2025.154720

Keywords: static load test pile base resistance load-settlement curve pile-bearing capacity

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Abstract

Field testing is the most relevant method for verifying pile foundation design calculations. The ultimate static load test allows the pile load to reach the maximum bearing capacity; however, the high cost of this method limits its use. The theory presented in this paper is based on static load test results performed in a specifically designed chamber that closely resembles natural soil conditions and pile dimensions. This study utilizes the Meyer–Kowalow theory and past works of the author on this topic to streamline the design process and reduce costs without compromising safety and reliability. It was concluded that the relationship between the toe and skin of the pile remained constant, and this was depicted using graphs showing the results under field conditions. This conclusion will be verified in future research by the author using more static load test results. The primary focus of this study was to develop a method for estimating pile-toe bearing capacities, which represents the most complex measurement method to solve. The previous works of the author focused on developing the calculus required to estimate the pile-skin bearing capacity, which was the first step in describing the pile–soil interaction. This study focused on verifying a mathematical model describing pile-toe behavior and calculations based on this model. This study provides practical equations for estimating pile-toe and skin resistance, which can improve the design process when using the proposed method.

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Authors and Affiliations

Paweł Siemaszko

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