Acta Polytechnica is a scientific journal published by CTU in Prague. The main title, Acta Polytechnica, is accompanied by the subtitle Journal of Advanced Engineering, which defines the scope of the journal more precisely - Acta Polytechnica covers a wide spectrum of engineering topics, physics and mathematics.    Our aim is to be a high-quality multi-disciplinary journal publishing the results of basic research and also applied research. We place emphasis on the quality of all published papers. The journal should also serve as a bridge between basic research in natural sciences and applied research in all technical disciplines.    The innovative research results published by young researchers or by postdoctoral fellows, and also the high-quality papers by researchers from the international scientific community, reflect the good position of CTU in the World University Rankings.    We hope that you will ﬁnd our journal interesting, and that it will serve as a valuable source of scientiﬁc information.

Acta Polytechnica is a scientific journal published by the Czech Technical University in Prague. The main title, Acta Polytechnica, is accompanied by the subtitle Journal of Advanced Engineering, which more precisely defines the scope of the journal. Acta Polytechnica covers a wide range of engineering topics, physics, and mathematics. Our aim is to be a high-quality multidisciplinary journal publishing the results of both basic and applied research. We place a strong emphasis on the quality of all published papers. The journal also serves as a bridge between basic research in the natural sciences and applied research across all technical disciplines. The innovative research results published by young researchers or postdoctoral fellows, along with high-quality papers from the international scientific community, reflect the strong position of the Czech Technical University in the World University Rankings. We hope you find our journal interesting and that it serves as a valuable source of scientific information.

《Acta Polytechnica》是由布拉格捷克科技大学出版的科学期刊。期刊的主标题为《Acta Polytechnica》，副标题为《先进工程期刊》，更精确地定义了期刊的范围。该期刊涵盖广泛的工程主题、物理学和数学。我们的目标是成为一个高质量的多学科期刊，发表基础研究和应用研究的成果。我们强调所有发表论文的质量。期刊还应作为自然科学基础研究与所有技术学科应用研究之间的桥梁。由年轻研究人员或博士后发表的创新研究成果，以及来自国际科学界的高质量论文，反映了捷克科技大学在世界大学排名中的良好地位。我们希望您会发现我们的期刊有趣，并且它将成为您获取科学信息的宝贵来源。

Acta Polytechnica

Underwater environment is still an attractive area to explore and exploit by human beings. However, underwater characteristics limit communications due to harsh channel conditions, and efficient channel codes are essential to deploy. This study presents an underwater system based on protograph low-density parity check (P-LDPC) codes and orthogonal frequency division multiplexing (OFDM) for image transmission. The system proves a successful reconstruction of P-LDPC coded images with different levels of comparison. The performance of the proposed system is evaluated using nine objective measures such as bit error rate (BER) and peak signal to noise ratio (PSNR). Firstly, the proposed system performance is evaluated with different block lengths of P-LDPC code. Then, the implemented system shows a coding gain of approximately 1.75 dB for applying P-LDPC when compared to polar with cyclic redundancy check at 0.0001 BER. Additionally, image subjective assessment is obtained to demonstrate how the P-LDPC outweighs polar and turbo product codes in terms of estimated image quality. Lastly, further investigation is performed to study the effect of varying fast Fourier transform (FFT) size and cyclic prefix (CP) length on image reserved quality. The results show that the received image is better reconstructed for larger FFT sizes since that produce longer CP and symbol duration, and that in turn helps the system to combat the multipath fading introduced by the underwater channel.

Aymen M. Al-Kadhimi

Ammar E. Abdelkareem

Charalampos C. Tsimenidis

P-LDPC coded image transmission with OFDM over underwater acoustic channel

基于P-LDPC编码和OFDM的水声信道图像传输

Nonlinear Fractional Volterra integral equations (FVIEs) of the first kind present challenges due to their intricate nature, combining fractional calculus and integral equations. In this research paper, we introduce a novel method for solving such equations using Leibniz integral rules. Our study focuses on a thorough analysis and application of the proposed algorithm to solve fractional Volterra integral equations. By using Leibniz integral rules, we offer a fresh perspective on handling these equations, shedding light on their fundamental properties and behaviours. As a result of this study, we anticipate contributing distinctively to the broader development of analytical tools and techniques. By bridging the gap between fractional calculus and integral equations, our approach not only offers a valuable computational methodology but also paves the way for new insights into the application domains in which such equations arise.

Mohammed Abdulshareef Hussein

Hassan Kamil Jassim

A novel approach to nonlinear fractional volterra integral equations

非线性分数阶Volterra积分方程的新方法

The paper presents the results of the modelling and study of the cutting process in the cut-in phase during the machining of external gears by the power skiving. The studies were carried out on the basis of the previously developed graphical model of the cut layers and the model of the cutting force as a function of the chip cross-sectional area, the shear strength limit of the workpiece material, and the intensity of plastic deformation during cutting. The regularities of the cutting force in the cut-in phase of gear machining are shown for successive tool revolutions in four passes with a gradual increase in the depth of cut. It is shown that the peak values of the cutting force at the contact between the front face of the cutter and the face plane are two times higher than under the conditions of steady stationary cutting in a preformed gap. At the same time, the amplitude of the cutting force and its average value over the cut-in passes are 1.7–3.7 times and 1.2–1.5 times higher, respectively, than the corresponding values of these parameters for steady state cutting. It is these peak jumps in the cutting force that limit the maximum depth of the cut, number of passes, and axial feed. Based on the data obtained, recommendations were developed to modify the traditional gear cutting scheme in power skiving. It is proposed to use short tool strokes with a low cutting depth along the length of the cut-in path and, after forming a gap in this area, to cut at a full depth to the full height of the gear rim. The possibility of a significant reduction of gear machining time using the proposed scheme of technological operation is demonstrated.

Ihor Hrytsai

Andrii Slipchuk

Study of non-stationary cutting processes in power skiving

功率滚削中非平稳切削过程的研究

This study investigates the impact of sheet metal thickness and strain generated on a cold forging process. A cold forging die was manufactured based on a numerically modelled product design that considered stress concentration die profiles. Experiments involved cold forging various sheet metals (lead, brass, aluminium, and steel) with thicknesses ranging from 2mm to 6mm to assess their influence on the thickness and strain. An assumption was formulated using Solidworks to determine the appropriate sheet metal thickness based on the material type. This assumption, based on volume considerations, showed practical applicability for selecting sheet metals with thicknesses close to those designed in the numerical modelling. The results revealed that softer materials, such as lead and aluminium, closely approximated the design thickness, particularly in the central region of the die profile, with error deviations of 1.14 % and 4.36 %, respectively. In contrast, harder materials demonstrated larger deviations from the design, with minimum errors of 4.94 % for brass and 5.73 % for steel. All sheet metals underwent compressive strain in the central region of the die profile due to the stamping operation. This work demonstrates a practical approach for selecting sheet metals based on material and thickness considerations, providing insights into the behaviour of different materials during the cold forging process.

Samya A. Nazal

Mohamed A. Nasser

Muammel M. Hanon

Hani A. Ameen

Investigation of the impact of product thickness and strain on cold forging processes

产品厚度与应变对冷锻工艺影响的调查研究

This paper presents a continuous severe plastic deformation (SPD) process for sheet metal called Dual Rolls Equal Channel Extrusion (DRECE) is introduced. The DRECE process achieves maximum sheet metal deformation by combining bending deformation with channel-angular shear deformation. The evolution of the microstructure and mechanical properties of the CuZn37 alloy has been experimentally investigated as a function of the number of repeated DRECE passes. The DRECE process was repeated up to four times at room temperature. As the number of passes increased, the character of the microstructure was gradually strongly deformed by intensive shear deformation. The microhardness and tensile properties changed significantly as a function of the number of repeated passes.

Martin Pastrňák

Radek Čada

Tomáš Pektor

Stanislav Rusz

František Tatíček

Jarosław Mizera

Marie Pastrňáková

Drece method for continuous severe plastic deformation of CuZn37 sheets

CuZn37板材连续严重塑性变形的双辊法

Composite materials including sandwich panels can offer a number of advantages such as excellent strength to mass ratio or stiffness to mass ratio. Sandwich panels can find their application in many industrial sectors where the mass and mechanical properties are critical. Despite these and many other advantages, the use of sandwich panels is associated with many problems, which stem from their structural composition (weak core with high shear stiffness connecting two skins with high in plane stiffness). This composition can cause problems in joining the sandwich panels to each other and to other parts by means of mechanical joints. To solve these problems, there exist many accessories such as inserts. The main objective of this paper is to present the development, manufacturing, and testing of plastic inserts for sandwich panels made by Fused Deposition Modelling 3D printing technology.

Abbreviation	Acta Polytech.
Journal Impact	0.60
Quartiles(Global)	ENGINEERING, MULTIDISCIPLINARY(Q3)

ISSN	1210-2709, 1805-2363
h-index	20

Publication Information	Publisher: Czech Technical University in Prague，Publishing cycle: ，Journal Type: journal，Open Access Journals: Yes
Basic data	Year of publication: 2011，Proportion of original research papers: 100.00%，Self Citation Rate:16.70%， Gold OA Rate: 97.74%
Average review cycle	网友分享经验：24 Weeks

Acta Polytechnica

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P-LDPC coded image transmission with OFDM over underwater acoustic channel

A novel approach to nonlinear fractional volterra integral equations

Study of non-stationary cutting processes in power skiving

Investigation of the impact of product thickness and strain on cold forging processes

Drece method for continuous severe plastic deformation of CuZn37 sheets

The application of 3D printing technology in the design of sandwich panels

A novel approach to nonlinear fractional volterra integral equations

Study of non-stationary cutting processes in power skiving

Investigation of the impact of product thickness and strain on cold forging processes

Drece method for continuous severe plastic deformation of CuZn37 sheets