Applied sciences

Bulletin of the Polish Academy of Sciences Technical Sciences

Content

Bulletin of the Polish Academy of Sciences Technical Sciences | 2026 | 74 | 3

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Abstract

In this paper, we utilize matrix transformations and inequalities to derive a novel upper bound and two lower bounds to solve the unified algebraic Lyapunov matrix equation (UALE). We then review existing bounds for the UALE and compare them with our new bounds, highlighting that our upper bound is the least restrictive among current results. The restrictions of our newly established lower bound are either weaker than the existing lower bounds or consistent with them. Our upper and lower bounds demonstrate increased accuracy over existing results through some numerical examples. As an application to linear systems, we illustrate how our upper bound can be employed to analyze the robust stability of the unified system based on the delta operator. Finally, we validate the effectiveness and superiority of our results through a series of numerical examples.
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Authors and Affiliations

Yan Xu
1
Jianzhou Liu
1
ORCID: ORCID

  1. School of Mathematics and Computational Science & Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education,Xiangtan University, Xiangtan, Hunan, 411105, PR China
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Abstract

Fast convergence is one of the core pursuit goals of modern high-performance control systems. This article investigates the fast convergence control problem of Markov jump systems. In order to ensure the feasibility of the fast convergence controller design method, the Lyapunov-Krasovskii functional is constructed based on Lyapunov stability theory in the derivation process of the algorithm. Based on a time-varying proportional function, a distributed control algorithm is designed and the fast convergence controller design method is proposed for the considered systems. The variation of controller gain with time is discussed in sections, and the boundary of controller output is given to make the designed controller more practical for real-world engineering applications. Finally, two simulation examples are given to demonstrate the effectiveness of the proposed method in this paper.
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Authors and Affiliations

Bo Li
1
ORCID: ORCID
Junjie Zhao
1
Xuejing Ren
2

  1. School of Electrical and Information Engineering, Jiangsu University of Technology, 1801 Zhongwu Road, Changzhou, Jiangsu, China
  2. School of Science, Changzhou Institute of Technology, 666 Liaohe Road, Changzhou, Jiangsu, China
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Abstract

The paper presents results of an investigation into a gas-delayed blowback operation firearm system. A recently developed experimental stand was used to this end. In this article, the results are subjected to statistical analysis using design of experiments methods, including response surface methodology (RSM). This analysis facilitates the determination of the significance and nature of parameters such as distance of the gas port from the breech end of the barrel, diameter of the gas port, mass of the recoiling assembly, diameter of the gas piston rod and length of the gas chamber that influence the operation of such systems. The results of the research can be used to validate a mathematical model of a weapon operating on this principle and serve as the starting point for the optimization process of this type of design.
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Authors and Affiliations

Dawid Goździk
1
ORCID: ORCID
Mateusz Morawski
1
ORCID: ORCID
Ryszard Woźniak
1
ORCID: ORCID
Mirosław Zahor
1
ORCID: ORCID
Radosław Trębiński
1
ORCID: ORCID

  1. Military University of Technology, Faculty of Mechatronics, Armament and Aerospace, ul. Kaliskiego 2, 00-908 Warsaw, Poland
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Abstract

This study proposes a method for estimating vehicle load using sinusoidal steering excitation and analysis of dynamic responses: lateral velocity (LV), roll velocity (RV) and yaw velocity (YV). The approach enables reliable discrimination between unloaded (W1) and loaded (W2) vehicle states under real driving conditions. Lateral velocity increases with vehicle speed and exhibits higher magnitudes for the loaded state, particularly within the 0.5–1.5 Hz range. Phase responses for W2 show stronger negative shifts and earlier transitions, indicating increased dynamic delay, which makes LV a useful supplementary indicator, especially at medium speeds. Roll velocity (RV) is identified as the most sensitive and repeatable response, and serves as the primary diagnostic variable. The largest differences between loading states occur within the 0.9–1.3 Hz range, where W2 responses exhibit higher amplitudes and a shift toward lower frequencies, directly reflecting increased vehicle mass. Above 2 Hz, system damping increases and load-related differences diminish. Yaw velocity (YV) shows amplitudes 1–3 dB higher for W2 within the 0.6–1.6 Hz range, together with phase shifts, but its sensitivity is lower than that of RV, classifying it as a supplementary indicator. Unlike methods based on complex identification algorithms or high-frequency measurements, this study adopts a simplified linear single-degree-of-freedom (1-DoF) oscillator model. Defined road-test conditions, including speeds of 45–56 km/h and excitation near 1.0 Hz, ensure dominance of a single dynamic mode. The method is computationally efficient and cost-effective, although its linear formulation may limit accuracy under strongly nonlinear dynamics or varying road conditions.
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Authors and Affiliations

Tomasz Pusty
1
ORCID: ORCID
Marcin Mieteń
1
Włodzimierz Kupicz
1

  1. The Military Institute of Armoured and Automotive Technology, 05-070 Sulejówek k. Warszawy, Poland
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Abstract

In this article, the influence of processing conditions, dopant type and poling temperature on the microstructure and piezoelectric
behavior of lead-free K0.5Bi0.5TiO3 (KBT) ceramics is presented. Base KBT samples and those doped with Sr, Ca and Mn were synthesized via a solid-state reaction route, and examined with respect to their structural characteristics and electromechanical response. Particular emphasis was placed on elevated-temperature poling and its interaction with grain morphology and defect chemistry. SEM observations were used to identify dopant-dependent microstructural variations, while measurements of the d33 coefficient provided insight into how these factors influence efficiency of the poling process. The study demonstrates the importance of jointly optimizing synthesis parameters, dopant selection and poling conditions when tailoring the functional properties of KBT-based piezoelectric ceramics.
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Authors and Affiliations

Piotr Rakus
1
ORCID: ORCID
Jarosław Jędryka
1
ORCID: ORCID
Piotr Czaja
2
ORCID: ORCID
Katarzyna Osińska
3

  1. Faculty of Electrical Engineering, Czestochowa University of Technology, Armii Krajowej 17, PL-42-201, Cz˛estochowa, Poland
  2. Institute of Technology, University of the National Education Commission, Krakow, Poland
  3. Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, Poland
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Abstract

Non-coding RNAs regulate diverse aspects of development, homeostasis, and disease. Among them, YRNA–derived small RNAs (s-RNYs) have attracted clinical interest as potential biomarkers due to their high abundance across human tissues, body fluids, and tumors. Despite major advances in understanding atherogenesis, the overall picture remains incomplete, limiting therapeutic progress. To address this gap, we built a systems model of atherogenesis using classical Petri nets, integrating recent insights of s-RNY functions in monocytes and macrophages alongside oxidative stress, inflammatory signaling, and key atherogenic pathways. Using t-invariant analysis, in silico knockouts, and dynamic simulations, we found that dual-target strategies, such as suppression of oxidative stress combined with inhibition of either (1) toll-like receptor 7 (TLR7), (2) s-RNYs, or (3) the pro-inflammatory cytokine interleukin-6 (IL-6), attenuate lesion progression. These findings support multipathway combination therapy as a promising direction to more effective treatment of atherosclerosis.
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Authors and Affiliations

Adam Trzebiatowski
1
ORCID: ORCID
Agnieszka Rybarczyk
1 2
ORCID: ORCID

  1. Faculty of Electrical Engineering, Gdynia Maritime University, 81-225 Gdynia, Poland
  2. Institute of Computing Science, Poznan University of Technology, 60-965 Poznan, Poland

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Articles submitted by December 31st, 2024: existing fee: 1500 PLN (and mandatory over-length charges of 230 PLN per page)
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