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Number of results: 5
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Abstract

Featured with a higher velocity, increased power handling capability, and better aging behavior, surface transverse wave (STW) shows more promising prospects than Rayleigh wave nowadays in various sensing applications. The need to design, optimize, and fabricate the related devices motivates the development of modeling and simulation. For this reason, a three-dimensional (3D) finite element (FE) simulation of STW on quartz, considering the crystal cut angle and the electrode effects, is presented in this study. Firstly, we investigated the effects of quartz’s cut angle on the generated waves. Here, the polarized displacements were analyzed to distinguish the wave modes. Secondly, the investigations of the electrode effects on the polarized displacement, phase velocity, and electromechanical coupling factor ( K2) were carried out, for which different material and thickness configurations for the electrodes were considered. Thirdly, to examine the excitation conditions of the generated waves, the admittance responses were inspected. The results showed that not only the crystal cut angle but also the density and the acoustic impedance of the interdigital transducer (IDT) material have a strong influence on the excited waves. This article is the first to analyze STWs considering quartz’s cut angle and electrode effect through a 3D FE model. It could provide a helpful and easy way to design, optimize, and fabricate the related surface acoustic wave devices.
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Authors and Affiliations

Chao Jiang
1 2 3
Xiaoli Cao
1 2
Feng Yang
1 2 3
Zejun Liu
1

  1. School of Computer Science and Information Engineering, Chongqing Technology and Business University, Chongqing, China
  2. Chongqing Key Laboratory of Intelligent Perception and Blockchain Technology, Chongqing Technology and Business University, Chongqing, China
  3. Chongqing Engineering Laboratory for Detection, Control and Integrated System, Chongqing Technology and Business University, Chongqing, China
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Abstract

It is essential for oceanographers to study the effects of marine phenomena such as currents, surface mixed layer, eddies, internal waves, and other ocean features on acoustic propagation, as most marine measurement equipment operates on this basis, like sonar. The eddy impact on acoustic transmission in the marine environment is very significant because changes in temperature and salinity disrupt the sound speed due to the presence of eddy, thus the acoustic propagation in the sea. Although cold eddies are in the Persian Gulf widely, one eddy is selected to study their impacts on acoustic propagation because they have similar properties in terms of temperature and salinity. In this research, after identifying eddies in the Persian Gulf automatically, the effect of a cold eddy on acoustic propagation was investigated at different depths using the BELLHOP model. Most eddies are cyclonic with 5–10 km of radius based on algorithm outputs. Studies on the lifespan of eddies showed that the occurrence of cyclonic eddies with a lifespan of more than three days is more than anticyclonic ones. Examination of the eddy effect on acoustic propagation showed that the transmission loss (TL) during the progress of the acoustic wave across the eddy increases with increasing the depth of the sound source. Also, the presence of cold eddy compared to the conditions it does not exist increases the transmission loss. The study of three-dimensional acoustic propagation also confirmed the obtained results in two-dimensional mode and clearly showed the role of cold eddy in increasing the TL.
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Authors and Affiliations

Omid Mahpeykar
1
Amir Ashtari Larki
1
Mohammad Akbari Nasab
2

  1. Department of Physical Oceanography, Faculty of Marine Science and Oceanography, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran
  2. Department of Marine Physics, Faculty of Marine and Oceanic Sciences, University of Mazandaran, Babolsar, Iran
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Abstract

More than 6 billion square metres of new buildings are built each year. This is about 1.2 million buildings. If we translate these figures into carbon footprint (CF) generated during the construction, it will be approximately 3.7 billion tons of carbon dioxide. The contractors all over the world – also in Poland – decide to calculate the carbon footprint for various reasons, but mostly they are compelled to do so by the market. The analysis of costs and emissions of greenhouse gases for individual phases of the construction system allows implementing solutions and preventing a negative impact on the environment without increasing the construction costs. The share of each phase in the amount of produced carbon for construction and use of the building depends mainly on the used materials and applied design solutions. Hence, the materials and solutions with lesser carbon footprint should be used. It can be achieved by using natural materials or materials which do not need much energy to be produced. The author will attempt to outline this idea and present examples of integrated analysis of costs and amount of carbon footprint during the building lifecycle.
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Authors and Affiliations

Krzysztof Zima
1
ORCID: ORCID

  1. DSc., PhD., Eng., Prof. CUT, Cracow University of Technology, Faculty of Civil Engineering, ul. Warszawska 24, 31-155 Krakow, Poland
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Abstract

Most of sound sources are complex vibroacoustic objects consist of numerous elements. Some coupled vibrating plates of different shapes and sizes can be easily found in urban environments. The main aim of this study is to determine the sound radiation of coupled plates system of practical importance. The investigated vibroacoustic system consist of a thin circular plate coupled with a thick flat baffle with a circular hole. The circular plate has been mounted to the baffle’s hole using screws and two steel rings. The measurement setup was located inside a semi-anechoic chamber to assure the free field conditions. It was necessary to take into account the whole system surface to obtain the radiation efficiency based on the Hashimoto’s method. Such an approach can be troublesome and time-consuming. Therefore, the criterion has been proposed which allows the vibration velocity measurements and calculations to be performed only for the thin plate’s area. An alternative approach has been proposed based on the classical Rayleigh integral formula. Its advantage is a simpler implementation in a computer code. The obtained results have been compared with the theoretical results obtained for the elastically supported circular plate. A good agreement has been obtained at low frequencies.

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Authors and Affiliations

Wojciech P. Rdzanek
Krzysztof Szmela
Wojciech Żyłka
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Abstract

The paper gives an introduction to nanostructuring techniques used for industrial fabrication of bulk nanocrystalline metals – basic

materials utilized in shaping nanoscale structures. Nanostructured metals, called nanometals, can be produced by severe plastic deformation (SPD). We give an expert coverage of current achievements in all important SPD methods and present future industry developments and research directions including both batch and continuous processes. In the laboratories of both WUT and UOS we have developed industry standard equipment and machinery for nanometals processing. Utilizing the latest examples from our research, we provide a concise introduction to the field of mass production of nanometals for nanotechnology.

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Authors and Affiliations

L. Olejnik
A. Rosochowski

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