Nauki Techniczne

Bulletin of the Polish Academy of Sciences Technical Sciences

Opis

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 | 2023 | 71 | 5

1 Contents 5/2023

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5

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2 Eigenvalues assignment in descriptor linear systems by state and its derivative feedbacks

Tadeusz Kaczorek

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e145765 | DOI: 10.24425/bpasts.2023.145765

Słowa kluczowe: eigenvalue assignment descriptor linear system state derivative feedback

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Abstrakt

The eigenvalues assignment problems for descriptor linear systems with state and its derivative feedbacks are considered herein. Necessary and sufficient conditions for the existence of solutions to the problems are established. The Euler and Tustin approximations of the continuous-time systems are analyzed. Procedures for computation of the feedbacks are given and illustrated by numerical examples.

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Autorzy i Afiliacje

Tadeusz Kaczorek

e-mail: t.kaczorek@pb.edu.pl

ORCID:

Bialystok University of Technology, Faculty of Electrical Engineering, Wiejska 45D, 15-351 Bialystok, Poland

3 Robust hybrid synchronization control of chaotic 3-cell CNN with uncertain parameters using smooth super twisting algorithm

Nazam Siddique , Fazal ur Rehman , Uzair Raoof , Shahid Iqbal , Muhammad Rashad

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e146474 | DOI: 10.24425/bpasts.2023.146474

Słowa kluczowe: hybrid synchronization cellular neural network sliding mode control smooth super twisting algorithm Lyapunov stability theory

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Abstrakt

This paper presents the control design framework for the hybrid synchronization (HS) and parameter identification of the 3-Cell Cellular Neural Network. The cellular neural network (CNN) of this kind has increasing practical importance but due to its strong chaotic behavior and the presence of uncertain parameters make it difficult to design a smooth control framework. Sliding mode control (SMC) is very helpful for this kind of environment where the systems are nonlinear and have uncertain parameters and bounded disturbances. However, conventional SMC offers a dangerous chattering phenomenon, which is not acceptable in this scenario. To get chattering-free control, smooth higher-order SMC formulated on the smooth super twisting algorithm (SSTA) is proposed in this article. The stability of the sliding surface is ensured by the Lyapunov stability theory. The convergence of the error system to zero yields hybrid synchronization and the unknown parameters are computed adaptively. Finally, the results of the proposed control technique are compared with the adaptive integral sliding mode control (AISMC). Numerical simulation results validate the performance of the proposed algorithm.

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Autorzy i Afiliacje

Nazam Siddique

e-mail:

ORCID:

Fazal ur Rehman

Uzair Raoof

Shahid Iqbal

Muhammad Rashad

University of Gujrat, Gujrat, Pakistan
Capital University of Science and Technology, Islamabad, Pakistan
University of Lahore, Lahore, Pakistan

4 Robust estimation based nonlinear higher order sliding mode control strategies for PMSG-WECS

Awais Nazir , Safdar Abbas Khan , Malak Adnan Khan , Zaheer Alam , Imran Khan , Muhammad Irfan , Saifur Rehman , Grzegorz Nowakowski

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e147063 | DOI: 10.24425/bpasts.2023.147063

Słowa kluczowe: WECS robust control MPPT back-stepping SMC super-twisting algorithm (STA) high gain observer ANN function fitting

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Abstrakt

The wind energy conversion systems (WECS) suffer from an intermittent nature of source (wind) and the resulting disparity between power generation and electricity demand. Thus, WECS are required to be operated at maximum power point (MPP). This research paper addresses a sophisticated MPP tracking (MPPT) strategy to ensure optimum (maximum) power out of the WECS despite environmental (wind) variations. This study considers a WECS (fixed pitch, 3KW, variable speed) coupled with a permanent magnet synchronous generator (PMSG) and proposes three sliding mode control (SMC) based MPPT schemes, a conventional first order SMC (FOSMC), an integral back-stepping-based SMC (IBSMC) and a super-twisting reachability-based SMC, for maximizing the power output. However, the efficacy of MPPT/control schemes rely on availability of system parameters especially, uncertain/nonlinear dynamics and aerodynamic terms, which are not commonly accessible in practice. As a remedy, an off-line artificial function-fitting neural network (ANN) based on Levenberg-Marquardt algorithm is employed to enhance the performance and robustness of MPPT/control scheme by effectively imitating the uncertain/nonlinear drift terms in the control input pathways. Furthermore, the speed and missing derivative of a generator shaft are determined using a high-gain observer (HGO). Finally, a comparison is made among the stated strategies subjected to stochastic and deterministic wind speed profiles. Extensive MATLAB/Simulink simulations assess the effectiveness of the suggested approaches.

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Autorzy i Afiliacje

Awais Nazir

Safdar Abbas Khan

Malak Adnan Khan

Zaheer Alam

Imran Khan

Muhammad Irfan

e-mail:

ORCID:

Saifur Rehman

Grzegorz Nowakowski

e-mail:

ORCID:

Department of Electrical Engineering, National University of Science and Technology, Pakistan
Department of Electronics Engineering, University of Engineering and Technology Peshawar, Abbottabad campus, Pakistan
Department of Electrical and Computer Engineering, COMSATS University Islamabad, Abbottabad Campus, Pakistan
Department of Electrical, Electronics and Computer Systems, College of Engineering and Technology, University of Sargodha, Pakistan
Electrical Engineering Department, College of Engineering, Najran University, Saudi Arabia
Faculty of Electrical and Computer Engineering, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland

5 Multi–server loss queueing system with random volume customers, non–identical servers and a limited sectorized memory buffer

Marcin Ziółkowski

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e146764 | DOI: 10.24425/bpasts.2023.146764

Słowa kluczowe: multi–server queueing system with heterogeneous servers queueing systems with random volume customers sectorized memory buffer loss probability Stieltjes convolution

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Abstrakt

In the present paper, the model of multi–server queueing system with random volume customers, non–identical (heterogeneous) servers and a sectorized memory buffer has been investigated. In such system, the arriving customers deliver some portions of information of a different type which means that they are additionally characterized by some random volume vector. This multidimensional information is stored in some specific sectors of a limited memory buffer until customer ends his service. In analyzed model, the arrival flow is assumed to be Poissonian, customers’ service times are independent of their volume vectors and exponentially distributed but the service parameters may be different for every server. Obtained results include general formulae for the steady–state number of customers distribution and loss probability. Special cases analysis and some numerical computations are attached as well.

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Autorzy i Afiliacje

Marcin Ziółkowski

e-mail:

ORCID:

Institute of Information Technology, Warsaw University of Life Sciences – SGGW, Poland

6 Model predictive ship trajectory tracking system based on line of sight method

Anna Miller

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e145763 | DOI: 10.24425/bpasts.2023.145763

Słowa kluczowe: model predictive control MPC ship control autonomous ship trajectory tracking line of sight LOS

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Abstrakt

Maritime Autonomous Surface Ships (MASS) perfectly fit into the future vision of merchant fleet. MASS autonomous navigation system combines automatic trajectory tracking and supervisor safe trajectory generation subsystems. Automatic trajectory tracking method, using line-of-sight (LOS) reference course generation algorithm, is combined with model predictive control (MPC). Algorithm for MASS trajectory tracking, including cooperation with the dynamic system of safe trajectory generation is described. It allows for better ship control with steady state cross-track error limitation to the ship hull breadth and limited overshoot after turns. In real MASS ships path is defined as set of straight line segments, so transition between trajectory sections when passing waypoint is unavoidable. In the proposed control algorithm LOS trajectory reference course is mapped to the rotational speed reference value, which is dynamically constrained in MPC controller due to dynamically changing reference trajectory in real MASS system. Also maneuver path advance dependent on the path tangential angle difference, to ensure trajectory tracking for turns from 0 to 90 degrees, without overshoot is used. All results were obtained with the use of training ship in real–time conditions.

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Autorzy i Afiliacje

Anna Miller

e-mail:

ORCID:

Gdynia Maritime University, ul. Morska 81-87, 81-225 Gdynia, Poland

7 A study on microbial self-healing concrete using expanded perlite

Usama Bin Amjad , Muhammad Shahid Siddique , Taha Shahid , Ahmed Iftikhar , Saleh M. Alogla , Jawad Ahmad

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e146475 | DOI: 10.24425/bpasts.2023.146475

Słowa kluczowe: concrete self-healing bacteria expanded perlite crack detection

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Abstrakt

The increasing concern for the safety and sustainability of structures is calling for the development of smart self-healing materials and preventive repair methods. This research is carried out to investigate the extent of self-healing in normal-strength concrete by using Sporosarcina aquimarina – NCCP-2716 immobilized in expanded perlite (EP) as the carrier. The efficacy of crack-healing was also tested using two alternative self-healing techniques, i.e. expanded perlite (EP) concrete and direct introduction of bacteria in concrete. A bacterial solution was embedded in EP and calcium lactate pentahydrate was added as the nutrient. Experiments revealed that specimens containing EP-immobilized bacteria had the most effective crack-healing. After 28 days of healing, the values of completely healed crack widths were up to 0.78 mm, which is higher than the 0.5 mm value for specimens with the direct addition of bacteria. The specimen showed a significant self-healing phenomenon caused by substantial calcite precipitation by bacteria. The induced cracks were observed to be repaired autonomously by the calcite produced by the bacteria without any adverse effect on strength. The results of this research could provide a scientific foundation for the use of expanded perlite as a novel microbe carrier and Sporosarcina aquimarina as a potential microbe in bacteria-based self-healing concrete.

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Autorzy i Afiliacje

Usama Bin Amjad

Muhammad Shahid Siddique

Taha Shahid

Ahmed Iftikhar

Saleh M. Alogla

Jawad Ahmad

Department of Civil Engineering, Military College of Engineering, Risalpur, sub-campus of National University of Sciences and Technology,Islamabad, Pakistan
Principal Scientific Officer / Program Leader at Pakistan Agricultural Research Council Islamabad, Pakistan
Department of Civil Engineering, College of Engineering, Qassim University, Buraydah 51452, Saudi Arabia

8 Maintaining technical readiness in the context of military exploitation systems

Anna Borucka

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e146619 | DOI: 10.24425/bpasts.2023.146619

Słowa kluczowe: readiness reliability safety technical objects preventive maintenance strategy renewal process

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Abstrakt

Readiness and reliability is a special attribute of rescue systems (army, police, fire service), where performance at the highest level is more important than economic efficiency. For this reason, special attention is given to the process of renewal of technical objects. In such systems, a preventive strategy is most often used. Though this is a safe model, it does not always take into account the specifics of the use of a technical object. Moreover, in some situations, it forces the end of life of a device that could still continue to operate as intended. The article analyzes precisely such technical objects, removed from operation after just 10 years of use. It was shown that such approach is not justified and that modern management strategies must be implemented also in relation to machinery and equipment operating in rescue systems. The most important achievements of the article are the use of reliability analysis methods in the systems where it is not common, and the indication of the benefits of such analysis. It has been shown that knowing the characteristics of reliability, you can consciously control each process and make decisions in this regard based on the technical condition of the facility and not on instructions. In the case under study, this would make it possible to undermine the decision to withdraw the analyzed objects from operation.

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Autorzy i Afiliacje

Anna Borucka

e-mail:

ORCID:

Military University of Technology, Warsaw, Poland

9 Analysis of the influence of the geometric features of the filler on the thermal properties and structure of the composites in the polypropylene matrix

Przemysław Postawa , Bartłomiej Jeż , Sylwester Norwiński , Aleksandra Kalwik

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e147064 | DOI: 10.24425/bpasts.2023.147064

Słowa kluczowe: polypropylene-based composites mechanical properties thermal properties fillers

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Abstrakt

The article presents the results of research on polymer composites based on polypropylene filled with various fillers. The physical and thermal properties of the composites are the result of the used polymer matrix as well as the properties and geometric features of the used filler. The geometric shape of the filler is particularly important in the processing of plastics in which the flow is forced, and high shearing tension occurs, which determines the high macromolecular orientation and specific arrangement of the filler particles. Thermal analysis (STA) was used in the research and photographs were taken using a scanning electron microscope (SEM) of fractures of polymer composites. The following fillers were used: talc, fibreglass, glass beads, and a halogen-free nitrogen-phosphorus flame retardant. The test material was obtained by extrusion. Shapes for strength tests, which were subjected to scanning microscopy tests after a static tensile test, were obtained by injection. The carried-out tests allowed us to determine the influence of the type and shape of individual fillers on structural changes in the structure of polypropylene composites and the degree of sample weight loss in a specific temperature range, depending on the used filler.

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Autorzy i Afiliacje

Przemysław Postawa

Bartłomiej Jeż

e-mail:

ORCID:

Sylwester Norwiński

Aleksandra Kalwik

Department of Technology and Automation, Faculty of Mechanical Engineering and Computer Science, Czestochowa University of Technology,Al. Armii Krajowej 19c, 42-200 Czestochowa, Poland

10 Mechanical properties and Mullins effect in rubber reinforced by montmorillonite

Anita Białkowska , Małgorzata Przybyłek , Marta Sola-Wdowska , Milan Masař , Mohamed Bakar

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e147059 | DOI: 10.24425/bpasts.2023.147059

Słowa kluczowe: rubber nanocomposites physical properties Mullins effect morphology

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Abstrakt

The present work investigated the properties of rubber vulcanizates containing different nanoparticles (Cloisite 20A and Cloisite Na+) and prepared using different sonication amplitudes. The results showed that a maximum improvement in tensile strength of more than 60% over the reference sample was obtained by the nanocomposites containing 2 wt.% Cloisite 20A and 1 wt.% Cloisite Na+ and mixed with a maximum amplitude of 270 µm. The modulus at 300% elongation increased by approximately 18% and 25% with the addition of 2 wt.% Cloisite 20A and 3 wt.% Cloisite Na+, respectively. The shape retention coefficient of rubber samples was not significantly affected by the mixing amplitude, while the values of the softness measured at the highest amplitude (270 µm) were higher compared to those of mixtures homogenized with lower amplitudes. The loading-unloading and loading-reloading processes showed similar trends for all tested nanocomposites. However, they increased with increasing levels of sample stretching but were not significantly affected by filler content at a given elongation. More energy was dissipated during the loading-unloading process than during the loading-reloading. SEM micrographs of rubber samples before and after cycling loading showed rough, stratified, and elongated morphologies. XRD results showed that elastomeric chains were intercalated in the MMT nanosheets, confirming the improvement of mechanical properties. The difference between the hydrophilic pristine nanoclay (Cloisite Na+) and organomodified MMT (Cloisite 20A) was also highlighted, while the peaks of the stretched rubber samples were smaller, regardless of the rubber composition, due most probably to the decrease of interlayer spacing.

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Autorzy i Afiliacje

Anita Białkowska

Małgorzata Przybyłek

Marta Sola-Wdowska

Milan Masař

Mohamed Bakar

e-mail:

ORCID:

University of Technology and Humanities in Radom, Faculty of Chemical Engineering and Commodity Science, Poland
Tomaš Bata University in Zlin, Centre of Polymer Systems, Czech Republic

11 Influence of plunger motion profile of high pressure die casting on the casting porosity and solidification rate

Katarzyna Żak , Rafał Dańko , Paweł L. Żak , Wojcich Kowalczyk

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | DOI: 10.24425/bpasts.2023.147339

Słowa kluczowe: high-pressure die casting computer simulation cooling rate numerical methods aluminium alloy

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Abstrakt

The high pressure die casting (HPDC) is a technique that allows us to produce parts for various sectors of industry. It has a great application in such sectors as automotive, energy, medicine, as the HPDC allows us to produce parts very fast and very cheaply. The HPDC casting quality depends on many parameters. The parameters among others, are cast alloy alloy metallurgy, filling system design, casting technology elements geometry and orientation, as well as, machine operation settings. In the article, different plunger motion schemes of the HPDC machine were taken into account. Analyses lead to learning about plunger motion influence on the casting porosity and solidification process run. Numerical experiments were run with the use of MAGMASoft® simulation software. Experiments were performed for industrial casting of water pump for automotive. Main parameter taken into account was maximal velocity of the plunger in the second phase. The analysis covered porosity distribution, feeding time through the gate, temperature field during whole process, solidification time. Cooling curves of the casting in chosen points were also analysed. Obtained results allow us to formulate conclusions that connect plunger motion scheme, gate solidification time and the casting wall thickness on the solidification rate and porosity of the casting.

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Autorzy i Afiliacje

Katarzyna Żak

e-mail:

ORCID:

Rafał Dańko

e-mail:

ORCID:

Paweł L. Żak

e-mail:

ORCID:

Wojcich Kowalczyk

AGH University of Krakow, Faculty of Foundry Engineering, al. Mickiewicza 30, 30-059 Kraków, Poland
Frech Poland Sp. z o.o., Przedmos´c, Główna 8, 46-320 Praszka, Poland

12 Application of high-speed camera measurements for determination of energy losses generated in a vibrating belt of CVT transmission

Waldemar Łatas , Adam Kot

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e146238 | DOI: 10.24425/bpasts.2023.146238

Słowa kluczowe: continuously variable transmission moving beam vibrations high-speed camera power losses

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Abstrakt

The paper presents a proposition of the theoretical-experimental method of determination of power losses in the transversely vibrating rubber V-belt of continuously variable transmission. The article comprises the results of experimental tests conducted on a special test stand with a complete scooter drivetrain powered by a small two-stroke internal combustion engine. Such a configuration allows ensuring real CVT working conditions. A high-speed camera was used for the contactless measurement of belt vibrations and time-lapse image analysis was performed in dedicated software. An axially moving Euler–Bernoulli beam was assumed as the mathematical model. Longitudinal vibrations and nonlinear effects were omitted. Additionally, it was assumed that the belt material behaves according to the Kelvin–Voigt rheological model. Analysis of the damped free vibrations of the cantilever beam, made of the belt segment, allowed to determine the equivalent bending damping coefficient. The CVT power losses, due to bending in the rubber transmission belt, were obtained for the fixed working conditions after numerical calculations. The proposed methodology is a new approach in this research area, which allows to obtain results impossible to achieve with other measurement methods.

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Autorzy i Afiliacje

Waldemar Łatas

e-mail:

ORCID:

Adam Kot

e-mail:

ORCID:

Department of Applied Mechanics and Biomechanics, Faculty of Mechanical Engineering, Cracow University of Technology, Poland
Department of Automotive Vehicles, Faculty of Mechanical Engineering, Cracow University of Technology, Poland

13 Comparison of main geometric characteristics of deformed sphere and standard spheroid

Vasyl Kovalchuk , Ivaïlo M. Mladenov

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e147058 | DOI: 10.24425/bpasts.2023.147058

Słowa kluczowe: deformed sphere standard spheroid sphericity index tipping (bifurcation) point for geodesics elliptic integrals and functions

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Abstrakt

In the paper we compare the geometric descriptions of the deformed sphere (i.e., the so-called λ-sphere) and the standard spheroid (namely, World Geodetic System 1984’s reference ellipsoid of revolution). Among the main geometric characteristics of those two surfaces of revolution embedded into the three-dimensional Euclidean space we consider the semi-major (equatorial) and semi-minor (polar) axes, quartermeridian length, surface area, volume, sphericity index, and tipping (bifurcation) point for geodesics. Next, the RMS (Root Mean Square) error is defined as the square-rooted arithmetic mean of the squared relative errors for the individual pairs of the discussed six main geometric characteristics. As a result of the process of minimization of the RMS error, we have obtained the proposition of the optimized value of the deformation parameter of the λ-sphere, for which we have calculated the absolute and relative errors for the individual pairs of the discussed main geometric characteristics of λ-sphere and standard spheroid (the relative errors are of the order of 10−6 – 10−9). Among others, it turns out that the value of the,sup> ^{flattening factor of the spheroid is quite a good approximation for the corresponding value of the deformation parameter of the λ-sphere (the relative error is of the order of 10−4).}

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Autorzy i Afiliacje

Vasyl Kovalchuk

e-mail:

ORCID:

Ivaïlo M. Mladenov

2 3

e-mail:

ORCID:

Institute of Fundamental Technological Research, Polish Academy of Sciences, Pawinskiego 5B, 02-106 Warsaw, Poland
Institute of Mechanics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 4, 1113 Sofia, Bulgaria
Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Tsarigradsko Chaussee 72, 1784 Sofia, Bulgaria

14 Time-slot based architecture for power beam-assisted relay techniques in CR-WSNs with transceiver hardware inadequacies

Mushtaq Muhammad Umer , Hong Jiang , Qiuyun Zhang , Liu ManLu , Muhammad Owais

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 5 | e146620 | DOI: 10.24425/bpasts.2023.146620

Słowa kluczowe: cognitive radio WSNs energy harvesting DF relaying relay selection schemes in WSNs hardware inadequacy in WSNs

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Abstrakt

Over the past two decades, numerous research projects have concentrated on cognitive radio wireless sensor networks (CR-WSNs) and their benefits. To tackle the problem of energy and spectrum shortfall in CR-WSNs, this research proposes an underpinning decode-&-forward (DF) relaying technique. Using the suggested time-slot architecture (TSA), this technique harvests energy from a multi-antenna power beam (PB) and delivers source information to the target utilizing energy-constrained secondary source and relay nodes. The study considers three proposed relay selection schemes: enhanced hybrid partial relay selection (E-HPRS), conventional opportunistic relay selection (C-ORS), and leading opportunistic relay selection (L-ORS). We present evidence for the sustainability of the suggested methods by examining the outage probability (OP) and throughput (TPT) under multiple primary users (PUs). These systems leverage time switching (TS) receiver design to increase end-to-end performance while taking into account the maximum interference constraint and transceiver hardware inadequacies. In order to assess the efficacy of the proposed methods, we derive the exact and asymptotic closed-form equations for OP and TPT & develop an understanding to learn how they affect the overall performance all across the Rayleigh fading channel. The results show that OP of the L-ORS protocol is 16% better than C-ORS and 75% better than E-HPRS in terms of transmitting SNR. The OP of L-ORS is 30% better than C-ORS and 55% better than E-HPRS in terms of hardware inadequacies at the destination. The L-ORS technique outperforms C-ORS and E-HPRS in terms of TPT by 4% and 11%, respectively.

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Autorzy i Afiliacje

Mushtaq Muhammad Umer

1 2

e-mail:

ORCID:

Hong Jiang

Qiuyun Zhang

e-mail:

ORCID:

Liu ManLu

e-mail:

ORCID:

Muhammad Owais

e-mail:

ORCID:

School of Information Engineering, Southwest University of Science & Technology (SWUST) Mianyang, 621010, P.R. China
Department of Software Engineering, Mirpur University of Science & Technology (MUST), Mirpur, Azad Jammu & Kashmir, Pakistan