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Number of results: 96
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Abstract

A condition which determines the location of technical infrastructure is an entrepreneur holding the right to use the property for construction purposes. Currently, there are parallel separate legal forms allowing the use of a real property for the purpose of locating transmission lines, i.e. transmission easement (right-of-way) established under the civil law and expropriation by limiting the rights to a property under the administrative law. The aim of the study is to compare these forms conferring the right to use real properties and to analyze the related surveying and legal problems occurring in practice. The research thesis of the article is ascertainment that the current legal provisions for establishing legal titles to a property in order to locate transmission lines need to be amended. The conducted study regarded legal conditions, extent of expropriation and granting right- of-way in the city of Krakow, as well as the problems associated with the ambiguous wording of the legal regulations. Part of the research was devoted to the form of rights to land in order to carry out similar projects in some European countries (France, Czech Republic, Germany, Sweden). The justification for the analysis of these issues is dictated by the scale of practical use of the aforementioned forms of rights to land in order to locate technical infrastructure. Over the period of 2011-2014, 651 agreements were concluded on granting transmission right-of-way for 967 cadastral parcels owned by the city of Krakow, and 105 expropriation decisions were issued, limiting the use of real properties in Krakow.
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Authors and Affiliations

Anna Trembecka
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Abstract

The present article investigates theoretically the refection and transmission through a lossless dielectric slab embedded between two semi−infinite left−handed materials (LHMs) in which the electric permittivity and magnetic permeability are simultaneously negative. The LHM is assumed to be dispersive according to Lorentz as well as Drude medium model. The reflection and transmission coefficients are studied with the angle of incidence, frequency and slab thickness. The effect of the damping frequency is also investigated. It is found that the damping frequency has an insignificant effect on reflected, transmitted and loss powers. Band pass filter is one of the possible applications of the proposed structure.

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Authors and Affiliations

S.A. Taya
D.M. El-Amassi
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Abstract

A verification study of ultrasound transmission numerical simulation results with experiment results is presented in this paper. The work considers a model of a transformer tank which is filled with electro insulating oil. In the experiment, performed under laboratory conditions, an ultrasound wave is generated by a piezoelectric transducer that is fixed in the centre of the tank and measured by another transducer mounted inside the tank at three distances: 10, 20 and 30 cm from the sound source. The transducer is able to measure and generate acoustic waves in the ultrasound frequency band up to 1 MHz. The simulation considers numerical calculation of acoustic pressure distribution inside the tank in which acoustic source emits waves with frequency equal to 100 kHz. Verification analysis has confirmed consistency of the numerically calculated values with the measurement results.

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Authors and Affiliations

Andrzej Cichoń
Daria Wotzka
Tomasz Boczar
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Abstract

There exist some possibilities for simultaneous delivery of laser radiation and ultrasounds of low frequency and high intensity: introducing ultrasound oscillations in the optical fiber by the rigid connection of the fiber to the vibrating element and non-contact influence of the ultrasonic wave on the laser beam. The article presents the results of Matlab simulations and experimental studies of influence of the ultrasonic wave on the laser beam. A role of the air gap, and its influence on laser-ultrasonic transmission in optical fiber was examined. Advantages and disadvantages of both solutions of interaction of ultrasonic and optical waves in, e.g., surgical applications are discussed.

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Authors and Affiliations

Tadeusz Gudra
Sylwia Muc
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Abstract

Over the years laser welding has evolved as a fabrication process capable of overcoming the limitations of conventional joining methodologies. It facilitates the welding of diverse range of materials like metals, non-metals, polymers etc. Laser transmission welding is a technique employed for fabricating intricate shapes/contours in polymers with better precision compared to the other conventional processes. Nylon6, a synthetic semi-crystalline polymer is utilized as an engineering thermoplastic due to its high strength and temperature resistant properties. In the earlier researches, various welding techniques were employed for the fabrication of polymers and metals keeping the laser beam stagnant, and much emphasis was given only to temperature distribution along the different axes and limited attention was given to residual stress analysis. Therefore, in this research work, a three-dimensional time-dependent model using a moving laser beam is used to fabricate unreinforced Nylon6 specimens.

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Authors and Affiliations

Santosh Kumar Gupta
Pradip Kumar Pal
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Abstract

The effect of the power amplifier on speech intelligibility in public address systems is often marginalised – i.e. it is assumed that it does not introduce significant signal distortion. This approach is justified when the linear range of the amplifier is used. The large crest factor of the speech signal and economic considerations mean that the amplifier also works in the non-linear range. In this paper, the effect of power amplifier distortion on the speech transmission index for public address systems (STIPA) is presented. In the first step, this influence was evaluated by measurements for Class AB and D amplifiers. Then, a computer model of the public address system based on the direct STIPA method, taking into account the non-linear properties of the amplifier, was proposed. Using the computer model, the optimum amplifier driving values were determined taking into account the reverberation time and interfering noise.
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Authors and Affiliations

Paweł Dziechciński
1

  1. Department of Acoustics, Multimedia and Signal Processing, Wrocław University of Science and Technology, Wrocław, Poland
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Abstract

In the past few years, overhead copper transmission lines have been replaced by lightweight aluminum transmission lines to minimize the cost and prevent the sagging of heavier copper transmission lines. High strength aluminum alloys are used as the core of the overhead transmission lines because of the low strength of the conductor line. However, alloying copper with aluminum causes a reduction in electrical conductivity due to the solid solution of each component. Therefore, in this study, the authors attempt to study the effect of various Al/Cu ratios (9:1, 7:3, 5:5) to obtain a high strength Al-Cu alloy without a significant loss in its conductivity through powder metallurgy. Low-temperature extrusion of Al/Cu powder was done at 350ºC to minimize the alloying reactions. The as-extruded microstructure was analyzed and various phases (Cu9Al4, CuAl2) were determined. The tensile strength and electrical conductivity of different mixing ratios of Al and Cu powders were studied. The results suggest that the tensile strength of samples is improved considerably while the conductivity falls slightly but lies within the limits of applications.

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Authors and Affiliations

Deokhyun Han
ORCID: ORCID
Geon-Hong Kim
Jaesung Kim
Byungmin Ahn
ORCID: ORCID
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Abstract

This paper explores the influence of linear gear tip relief modification on power transmission efficiency. In real time applications gears experience transmission error (TE) during operation which increases noise and vibration and also results in increased tooth profile deformation during operation of the gear. By providing tip relief profile modification this TE can be decreased. Using MATLAB for computation and ANSYS for the simulation of deformation, stress, strain, life, and factor of safety results for the gear assemblies are obtained. Deformation results are used for the computation change in power transmission efficiency followed by the modal and harmonic analysis of the gears and gear assemblies to determine change in the first mode of natural frequency.

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Authors and Affiliations

Narendiranath Babu Thamba
Abhijeet Mukund Tambare
Krishna Caitanya Ananthanarayanan
Rama Prabha Duraiswamy
Shankar Thangavelu
Raj Kumar Easwara Pillai
Ramalinga Viswanathan Mangalaraja
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Abstract

This paper presents the design of a compact protocol for fixed-latency, high-speed, reliable, serial transmission between simple field-programmable gate arrays (FPGA) devices. Implementation of the project aims to delineate word boundaries, provide randomness to the electromagnetic interference (EMI) generated by the electrical transitions, allow for clock recovery and maintain direct current (DC) balance. An orthogonal concatenated coding scheme is used for correcting transmission errors using modified Bose–Chaudhuri–Hocquenghem (BCH) code capable of correcting all single bit errors and most of the double-adjacent errors. As a result all burst errors of a length up to 31 bits, and some of the longer group errors, are corrected within 256 bits long packet. The efficiency of the proposed solution equals 46.48%, as 119 out of 256 bits are fully available to the user. The design has been implemented and tested on Xilinx Kintex UltraScale+ KCU116 Evaluation Kit with a data rate of 28.2 Gbps. Sample latency analysis has also been performed so that user could easily carry out calculations for different transmission speed. The main advancement of the work is the use of modified BCH(15, 11) code that leads to high error correction capabilities for burst errors and user friendly packet length.

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Authors and Affiliations

Michał Kruszewski
Wojciech Marek Zabołotny
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Abstract

The construction of transmission infrastructure and its functioning imposes the obligation on transmission companies to have a legal title to land. Both in Poland and in Canada, the title particularly results from the established easements subject to registration in public information systems. Due to different historical, social, and economic conditions, the specificity of legal regulations and technical solutions related to the registration of rights to land property is different in both countries. This results from the functioning and the substantive scope of particular systems of information on land property. Such systems are regulated by independent, internal rules of each of the countries. In Poland, easement is subject to registration in the land and mortgage register. In Canada, a federation country, it depends on legal regulations of particular provinces. The research objective of the article is the analysis of the way of registration of easements established for transmission companies in Poland and in Canada in the Ontario and Quebec provinces. The analysis covers the scope of registration of the said right in systems of information on land property. The evaluation of the applied solutions particularly involves pointing out those which to the greatest extent guarantee the safety of land property turnover. The best result is obtained in Canada in the Ontario province.
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Authors and Affiliations

Natalia Sajnóg
Katarzyna Sobolewska-Mikulska
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Abstract

This article presents an efficient method of modelling acoustic phenomena for real-time applications such as computer games. Simplified models of reflections, transmission, and medium attenuation are described along with assessments conducted by a professional sound designer. The article introduces representation of sound phenomena using digital filters for further digital audio processing.
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Authors and Affiliations

Bartłomiej Miga
Bartosz Ziółko
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Abstract

The possibility of acoustic wave propagation in optical waveguides creates new prospects for simultaneous transmission of laser beams and ultrasonic waves. Combined laser-ultrasonic technology could be useful in e.g. surgical treatment. The article presents the results of experimental studies of transmission of ultrasonic wave in optical fibres, the core of which is doped by 7.5% of TiO2, using a sandwich-type transducer. It also presents amplitude characteristics of an ultrasonic signal propagated in the optical fibre. Authors studied the effect which the length of the fibre has on the achieved output signal amplitudes. They presented the relation of the output signal amplitude from a capacitive sensor to the power applied to the sandwich-type transducer. The obtained results were compared with the results produced when using an optical fibre with a core doped by 3% of GeO2, in order to select optical fibre suitable for simultaneous transmission of ultrasonic waves and laser rays.

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Authors and Affiliations

Sylwia Muc
Tadeusz Gudra
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Abstract

The article presents results of our own research regarding acoustic properties of 110 classrooms in five typical primary schools in Warsaw. The target of the research was to assess the classrooms using established criteria. These criteria include the reverberation time and the speech transmission index. The research has shown a large diversity of acoustic properties of classrooms within each of the schools and between the schools, resulting from the classroom equipment and the school building construction. In addition, the assessment has indicated that classrooms in schools researched do not meet the established acoustic criteria (reverberation time and speech transmission index). Because the classroom equipment is different for younger forms (integrated teaching) and for older forms (subject teaching), the results have been analyzed separately for rooms for younger forms (0-III) and for rooms for older forms (IV-VI). Synthetic results prove the advisability of such division. Correlation analysis has been conducted for the speech transmission index STI and reverberation time Tmf, as well as for the speech transmission index STI and the suggested reverberation time Twf defined in a similar manner as Tmf, but in a wider frequency range. The correlation between the speech transmission index STI and Twf is higher than that between the STI index and Tmf. The reverberation time Twf can therefore be used for a more precise assessment of acoustic properties of interiors with regard to verbal communication than Tmf. In addition, the paper presents estimated analysis results of the influence of selected classroom equipment (carpets) on its acoustic properties.

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Authors and Affiliations

Witold Mikulski
Jan Radosz
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Abstract

This paper presents and analyses the results of a simulation of the acoustic field distribution in sectors of a 1024-element ring array, intended for the diagnosis of female breast tissue with the use of ultrasonic tomography. The array was tested for the possibility to equip an ultrasonic tomograph with an additional modality - conventional ultrasonic imaging with the use of individual fragments (sections) of the ring array. To determine the acoustic field for sectors of the ring array with a varying number of activated ultrasonic transducers, a combined sum of all acoustic fields created by each elementary transducer was calculated. By the use of MATLAB software, a unique algorithm was developed, for a numerical determination of the distribution of pressure of an ultrasonic wave on any surface or area of the medium generated by the concave curvilinear structure of rectangular ultrasound transducers with a geometric focus of the beam. The analysis of the obtained results of the acoustic field distribution inside the ultrasonic ring array used in tomography allows to conclude that the optimal number of transducers in a sector enabling to obtain ultrasound images using linear echographic scanning is 32 ≤ n ≤ 128, taking into account that due to an increased temporal resolution of ultrasonic imaging, this number should be as low as possible.

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Authors and Affiliations

Wiktor Staszewski
Tadeusz Gudra
Krzysztof J. Opieliński
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Abstract

Transmission of vibroacoustic energy from an internal combustion engine (ICE) to its surroundings largely depends on how it is mounted, on available transmission paths and on the construction of the vehicle body and/or its surrounding structures. This is especially true in low speed engines in enclosed areas which generate perceptually weak noise, but strong low-frequency waves which energy has a negative impact on human health, comfort and driving safety especially in prolonged exposure to the source. The primary aim of the article was to analyse components of the ICE unit which had a determining impact on the reduction of low-frequency waves. Thus, the structurally transmitted noise from the ICE to its surrounding structure (body of the passenger vehicle) was analysed. The results of the vibroacoustic measurements were compared to modal analysis in order to determine possible resonance sources in the vehicle body and/or for assessing the influence of the vehicles safety gear on the generated vibroacoustic energy transfer into the cabin area of the passenger vehicle. Measurements were made for a passenger vehicle at rest and operating in its most common operational speed as well as for the stationary ICE of a cogenerate unit (CGU). Measurements and FFT analysis were used for the detection of the vibroacoustic energy sound pressure level (noise) and mechanical vibration. Firstly, the low-frequency noise sources were determined and their direct effects on the human body were investigated. Finally, this paper suggests some measures which may contribute to the reduction of undesirable vibroacoustic energy in enclosed areas.
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Authors and Affiliations

Stanislav Žiaran
Ondrej Chlebo
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Abstract

The results of shielding effectiveness (SE) measurements of textile materials containing metal by the free-space transmission technique (FSTT) in the 1-26.5 GHz frequency range are presented in the paper. It is shown that experimental data processing using time-domain gating (TDG) makes it possible to effectively remove diffracted and reflected components from the desired signal. The comparison with the results obtained by other techniques, namely modified FSTT with TDG and coaxial line probe technique (ASTM D4935-99) is given. The comparison shows that the proposed technique gives more reasonable results while the measurement set-up is simpler in realization.

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Authors and Affiliations

Nadezhda Dvurechenskaya
Paweł R. Bajurko
Ryszard J. Zieliński
Yevhen Yashchyshyn
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Abstract

A new configuration of rectifier suiting CMOS technology is presented. The rectifier consists of only two n-channel MOS transistors, two capacitors and two resistors; for this reason it is very favourable in manufacturing in CMOS technology. With these features the rectifier is easy to design and cheap in production. Despite its simplicity, the rectifier has relatively good characteristics, the voltage and power efficiency, and bandwidth greater than 89%, 87%, and 1 GHz, respectively. The performed simulations and measurements of a prototype circuit fully confirmed its correct operation and advantages.

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Authors and Affiliations

Waldemar Jendernalik
Jacek Jakusz
Grzegorz Blakiewicz
Miron Kłosowski
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Abstract

Main aim of this study is to combine the characteristics of the sonic crystal (SC) with acoustic panels and porous materials to improve the sound transmission loss (STL) through the triple-panel structure. SCs cause a bandgap centered around a certain frequency (Bragg’s frequency) due to generation of destructive interference. Initially, an analytical method is developed that extends the previous theory of double-panel structure to predict STL through a triple-panel structure. Finite element (FE) simulations are performed to obtain the STL through the triple-panel, which are validated with the analytical predictions. Various configurations are analyzed using the FE method based on the method of inserting the porous material and SCs between the panels to address the combined effect. STL through the triple-panel structure is compared with that through the double-panel structure having the same total weight and total thickness. It is found that the combined structure of the triple panel and the SC with glass wool as filler gives the best soundproof performance for the same external dimensions. For narrow air gaps, filing with glass wool is more advantageous than inserting one row of SC. In addition, the triple panel combined with a SC has better soundproofing than the two-panel counterparts.

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Authors and Affiliations

Myong-Jin Kim
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Abstract

Sound insulation of the finite double-panel structure (DPS) inserted with a cylindrical shell array is investigated by varying the sound incidence direction to improve its applicability. The effects of the vibro-acoustic characteristics of its constituents on the sound transmission loss (STL) are estimated in one-third octave bands from 20 Hz to 5 kHz for different incidence conditions. It shows that the first acoustic mode in the direction parallel to two panels (longitudinal modes) produces both the sudden variation of sound insulation with frequency and a large dependency on the incidence angle. Mineral wools are placed on two boundaries perpendicular to the panels, and the sound insulation is explored for different thicknesses of the porous materials. An absorbent layer with a certain thickness (more than 30 mm in our work) sufficiently eliminates the longitudinal mode, resulting in the improvement in the sound insulation by more than 15 dB and the decrease of its large variation with incidence direction. STLs with varying shell thicknesses are also assessed. It shows that the natural vibrations of the thin shells can give an enhancement in sound insulation by more than 10 dB in the frequency range of 1600–3700 Hz, corresponding to constructive interference.
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Authors and Affiliations

Song-Hun Kim
1
Myong-Jin Kim
1

  1. Institute of Acoustics, Department of Physics, Kim Il Sung University, Pyongyang, Democratic People’s Republic of Korea
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Abstract

In this paper, a 2D numerical modeling of sound wave propagation in a shallow water medium that acts as a waveguide, are presented. This modeling is based on the method of characteristic which is not constrained by the Courant–Friedrichs–Lewy (CFL) condition. Using this method, the Euler time-dependent equations have been solved under adiabatic conditions inside of a shallow water waveguide which is consists of one homogeneous environment of water over a rigid bed. In this work, the stability and precision of the method of characteristics (MOC) technique for sound wave propagation in a waveguide were illustrated when it was applied with the semi-Lagrange method. The results show a significant advantage of the method of characteristics over the finite difference time domain (FDTD) method.
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Authors and Affiliations

Mohammad Reza Khalilabadi
1

  1. Faculty of Naval Aviation, Malek Ashtar University of Technology, Iran
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Abstract

For the purpose of reducing the impact noise transmission across floating floors in residential buildings, two main sound transmission paths in the floating floor structure are considered: the stud path and the cavity path. The sound transmission of each path is analysed separately: the sound transmission through the cavity and the stud are predicted by statistical energy analysis (SEA). Then, the sound insulation prediction model of the floating floor is established. There is reasonable agreement between the theoretical prediction and measurement, and the results show that a resilient layer with low stiffness can attenuate the sound bridge effect, resulting in higher impact noise insulation. Then, the influences of the floor covering, the resilient layer and the floor plate on the impact sound insulation are investigated to achieve the optimised structure of the floating floor based on the sound insulation.
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Authors and Affiliations

Xianfeng Huang
1 2
Yimin Lu
3
Chen Qu
1
Chenhui Zhu
1

  1. College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China
  2. Guangxi Key Laboratory of Disaster Prevention and Engineering Safety, Guangxi University, Nanning 530004, China
  3. School of Electrical Engineering, Guangxi University, Nanning 530004, China
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Abstract

The problem of reducing noise in transportation is an important research field to prevent accidents and to provide a civilised environment for people. A material that has recently attracted attention in research to reduce noise is acoustic metamaterial, and most of the research projects so far have been limited to the case of static media without flow. We have studied the sound transmission properties of the acoustic metamaterials with turbulent flow to develop the acoustic metamaterials that are used in transportation. In this paper, the effects of geometrical structure, convection, and eddy on sound propagation in the acoustic metamaterials with turbulent flow are investigated, and the relationships between them are analysed. The effects of convection and eddy reduce the resonant strength of the sound transmission loss resulting from the unique geometry of the acoustic metamaterials, but move the resonant frequencies to opposite directions. In addition, when the convective effect and the eddy effect of the airflow, as well as the intrinsic interaction effect generated from the unique geometrical structure of the acoustic metamaterials cannot be ignored, they exhibit competition phenomena with each other, resulting in a widening of the resonance peak. As a result, these three effects cause the shift of the resonance frequency of the sound transmission loss and the widening of the resonance peak. The results of this study show that even in the case of turbulent flow, the metamaterials can be used for transportation by properly controlling its geometric size and shape.
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Authors and Affiliations

Myong Chol Pak
1
Kwang-Il Kim
1
Hak Chol Pak
1
Kwon Ryong Hong
2

  1. Department of Physics, Kim Il Sung University, Taesong District, Pyongyang, Democratic People’s Republic of Korea
  2. Institute of Natural Sciences, Kim Il Sung University, Taesong District, Pyongyang, Democratic People’s Republic of Korea
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Abstract

In this study, the effect of the emergence angle of a source array on acoustic transmission in a typical shallow sea is simulated and analyzed. The formula we derived for the received signal based on the Normal Mode indicates that the signal is determined by the beamform on the modes of all sources and the samplings of all modes at the receiving depth. Two characteristics of the optimal emergence angle (OEA) are obtained and explained utilizing the aforementioned derived formula. The observed distributions of transmission loss (TL) for different sources and receivers are consistent with the obtained characteristics. The results of this study are valuable for the development and design of active sonar detection.

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Authors and Affiliations

Yanyang Lu
Kunde Yang
Hong Liu
Chunlong Huang

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