In both fixed and rotary wing aircraft, the move toward lighter structures has resulted in an increase in structural vibration and interior noise. Porous materials have been proposed as acoustic absorbers to reduce this noise. This paper discusses the development of equipment at the NASA Glenn Research Center for characterizing the acoustic performance of porous materials: a flow resistance apparatus to measure the pressure drop across a specimen of porous material, and a standing wave tube that uses a pair of stationary microphones to measure the normal incidence acoustic impedance of a porous material specimen. Specific attention is paid to making this equipment as flexible as possible in terms of specimen sizes need for testing to accommodate the small or irregular sizes often produced during the development phase of a new material. In addition, due to the unknown performance of newly developed material, safety features are included on the flow resistance apparatus to contain test specimens that shed particles or catastrophically fail during testing. Results of measurements on aircraft fiberglass are presented to verify the correct performance of the equipment.
{"title":"Development of Instrumentation for the Measurement of the Performance of Acoustic Absorbers","authors":"J. C. Johnston, M. Kuczmarski, Garth Olszko","doi":"10.4236/OJA.2015.54014","DOIUrl":"https://doi.org/10.4236/OJA.2015.54014","url":null,"abstract":"In both fixed and rotary wing aircraft, the move toward lighter structures has resulted in an increase in structural vibration and interior noise. Porous materials have been proposed as acoustic absorbers to reduce this noise. This paper discusses the development of equipment at the NASA Glenn Research Center for characterizing the acoustic performance of porous materials: a flow resistance apparatus to measure the pressure drop across a specimen of porous material, and a standing wave tube that uses a pair of stationary microphones to measure the normal incidence acoustic impedance of a porous material specimen. Specific attention is paid to making this equipment as flexible as possible in terms of specimen sizes need for testing to accommodate the small or irregular sizes often produced during the development phase of a new material. In addition, due to the unknown performance of newly developed material, safety features are included on the flow resistance apparatus to contain test specimens that shed particles or catastrophically fail during testing. Results of measurements on aircraft fiberglass are presented to verify the correct performance of the equipment.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"172-192"},"PeriodicalIF":0.0,"publicationDate":"2015-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70558085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problem of diffraction of a plane acoustic wave by a finite soft (rigid) cone is investigated. This one is formulated as a mixed boundary value problem for the three-dimensional Helmholtz equation with Dirichlet (Neumann) boundary condition on the cone surface. The diffracted field is sought as expansion of unknown velocity potential in series of eigenfunctions for each region of the existence of sound pressure. The solution of the problem then is reduced to the infinite set of linear algebraic equations (ISLAE) of the first kind by means of mode matching technique and orthogonality properties of the Legendre functions. The main part of asymptotic of ISLAE matrix element determined for large indexes identifies the convolution type operator amenable to explicit inversion. This analytical treatment allows one to transform the initial diffraction problem into the ISLAE of the second kind that can be readily solved by the reduction method with desired accuracy depending on a number of truncation. All these determine the analytical regularization method for solution of wave diffraction problems for conical scatterers. The boundary transition to soft (rigid) disc is considered. The directivity factors, scattering cross sections, and far-field diffraction patterns are investigated in both soft and rigid cases whereas the main attention in the near-field is focused on the rigid case. The numerically obtained results are compared with those known for the disc.
{"title":"Diffraction of a Plane Acoustic Wave from a Finite Soft (Rigid) Cone in Axial Irradiation","authors":"D. Kuryliak, Z. Nazarchuk, Victor Lysechko","doi":"10.4236/OJA.2015.54015","DOIUrl":"https://doi.org/10.4236/OJA.2015.54015","url":null,"abstract":"The problem of diffraction of a plane acoustic wave by a finite soft (rigid) cone is investigated. This one is formulated as a mixed boundary value problem for the three-dimensional Helmholtz equation with Dirichlet (Neumann) boundary condition on the cone surface. The diffracted field is sought as expansion of unknown velocity potential in series of eigenfunctions for each region of the existence of sound pressure. The solution of the problem then is reduced to the infinite set of linear algebraic equations (ISLAE) of the first kind by means of mode matching technique and orthogonality properties of the Legendre functions. The main part of asymptotic of ISLAE matrix element determined for large indexes identifies the convolution type operator amenable to explicit inversion. This analytical treatment allows one to transform the initial diffraction problem into the ISLAE of the second kind that can be readily solved by the reduction method with desired accuracy depending on a number of truncation. All these determine the analytical regularization method for solution of wave diffraction problems for conical scatterers. The boundary transition to soft (rigid) disc is considered. The directivity factors, scattering cross sections, and far-field diffraction patterns are investigated in both soft and rigid cases whereas the main attention in the near-field is focused on the rigid case. The numerically obtained results are compared with those known for the disc.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"193-206"},"PeriodicalIF":0.0,"publicationDate":"2015-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70558184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. F. Cordeiro, A. Montagnoli, Maysa Tibério Ubrig, M. H. Menezes, D. Tsuji
Aim: The aim is to compare the vocal fold vibration seen during lip and tongue trills with that seen during phonation of the sustained vowel /e/, in terms of the periodicity of the EGG waveform and the amplitude of the EGG signal, in professional voice users. Study design: This was a quasi-experimental study. Methods: We used electroglottography (EGG) to compare the vocal fold vibration seen during tongue and lip trills with that seen during phonation of the sustained vowel /e/, in terms of the EGG waveform periodicity and signal amplitude, in 10 classically trained, professional singers. The participants produced the sustained vowel /e/ and performed tongue and lip trills at the same frequency and intensity. The periodicity of the waveform and the amplitude of the signal were visually analyzed by three blinded, experienced readers. To confirm the visual analysis results, we measured the jitter and shimmer of the signal and the frequency of variation in vocal fold vibration during the trill exercises. Results: The EGG waveform was classified as periodic for the sustained vowel phonation task and as quasi-periodic for the trill exercises, the vibration pattern repeating at approximately 24 Hz. Conclusion: The vibration of the vocal folds was modified according to the supraglottic movement in trills exercises.
{"title":"Comparison of Tongue and Lip Trills with Phonation of the Sustained Vowel /ε/ Regarding the Periodicity of the Electroglottographic Waveform and the Amplitude of the Electroglottographic Signal","authors":"G. F. Cordeiro, A. Montagnoli, Maysa Tibério Ubrig, M. H. Menezes, D. Tsuji","doi":"10.4236/OJA.2015.54018","DOIUrl":"https://doi.org/10.4236/OJA.2015.54018","url":null,"abstract":"Aim: The aim is to compare the vocal fold vibration seen during lip and tongue trills with that seen during phonation of the sustained vowel /e/, in terms of the periodicity of the EGG waveform and the amplitude of the EGG signal, in professional voice users. Study design: This was a quasi-experimental study. Methods: We used electroglottography (EGG) to compare the vocal fold vibration seen during tongue and lip trills with that seen during phonation of the sustained vowel /e/, in terms of the EGG waveform periodicity and signal amplitude, in 10 classically trained, professional singers. The participants produced the sustained vowel /e/ and performed tongue and lip trills at the same frequency and intensity. The periodicity of the waveform and the amplitude of the signal were visually analyzed by three blinded, experienced readers. To confirm the visual analysis results, we measured the jitter and shimmer of the signal and the frequency of variation in vocal fold vibration during the trill exercises. Results: The EGG waveform was classified as periodic for the sustained vowel phonation task and as quasi-periodic for the trill exercises, the vibration pattern repeating at approximately 24 Hz. Conclusion: The vibration of the vocal folds was modified according to the supraglottic movement in trills exercises.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"226-238"},"PeriodicalIF":0.0,"publicationDate":"2015-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70557810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we want to make a new type linear piezoelectric motor by mode shape coating or effective electrode surface coating. The mode shape is derived from the mechanical boundary conditions of the linear piezoelectric motor. We only have access to the first three modes of formas, the effective electrode surface coating basis, as well as with the linear piezoelectric motor of normal shape do comparison. Next, we will inspect their gain or axial velocity through theoretical analysis, simulation and experiment. According to the results of the theoretical analysis, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much larger than the linear piezoelectric motors of normal shape. However, according to the results of simulation and experiments, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much greater than the linear piezoelectric motors of normal shape, which is about 1.2 to 1.4 times. The linear piezoelectric motor of mode shape 3 has the fastest axial velocity, which is about -48 mm/s and 48 mm/s under conditions of 180 Vp-p driving voltage, 21.2 kHz driving frequency (the third vibration modal), 25 gw loading and the position of loading or mass at x = 5 mm & 45 mm respectively. And its axial velocity is about 1.4 times the linear piezoelectric motor of normal shape under the same conditions. Overall, the mode shape coating helps to enhance the gain or axial velocity of the linear piezoelectric motor.
{"title":"A Study on the Linear Piezoelectric Motor of Mode Shape","authors":"J. Jou","doi":"10.4236/OJA.2015.54013","DOIUrl":"https://doi.org/10.4236/OJA.2015.54013","url":null,"abstract":"In this paper, we want to make a new type linear piezoelectric motor by mode shape coating or effective electrode surface coating. The mode shape is derived from the mechanical boundary conditions of the linear piezoelectric motor. We only have access to the first three modes of formas, the effective electrode surface coating basis, as well as with the linear piezoelectric motor of normal shape do comparison. Next, we will inspect their gain or axial velocity through theoretical analysis, simulation and experiment. According to the results of the theoretical analysis, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much larger than the linear piezoelectric motors of normal shape. However, according to the results of simulation and experiments, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much greater than the linear piezoelectric motors of normal shape, which is about 1.2 to 1.4 times. The linear piezoelectric motor of mode shape 3 has the fastest axial velocity, which is about -48 mm/s and 48 mm/s under conditions of 180 Vp-p driving voltage, 21.2 kHz driving frequency (the third vibration modal), 25 gw loading and the position of loading or mass at x = 5 mm & 45 mm respectively. And its axial velocity is about 1.4 times the linear piezoelectric motor of normal shape under the same conditions. Overall, the mode shape coating helps to enhance the gain or axial velocity of the linear piezoelectric motor.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"153-171"},"PeriodicalIF":0.0,"publicationDate":"2015-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70558068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Room Acoustic Rendering Equation introduced in [1] formalizes a variety of room acoustics modeling algorithms. One key concept in the equation is the Acoustic Bidirectional Reflectance Distribution Function (A-BRDF) which is the term that models sound reflections. In this paper, we present a method to compute analytically the A-BRDF in cases with diffuse reflections parametrized by random variables. As an example, analytical A-BRDFs are obtained for the Vector Based Scattering Model, and are validated against numerical Monte Carlo experiments. The analytical computation of A-BRDFs can be added to a standard acoustic ray tracing engine to obtain valuable data from each ray collision thus reducing significantly the computational cost of generating impulse responses.
{"title":"Analytical Computation of Acoustic Bidirectional Reflectance Distribution Functions","authors":"J. Durany, T. Mateos, A. Garriga","doi":"10.4236/OJA.2015.54016","DOIUrl":"https://doi.org/10.4236/OJA.2015.54016","url":null,"abstract":"The Room Acoustic Rendering Equation introduced in [1] formalizes a variety of room acoustics modeling algorithms. One key concept in the equation is the Acoustic Bidirectional Reflectance Distribution Function (A-BRDF) which is the term that models sound reflections. In this paper, we present a method to compute analytically the A-BRDF in cases with diffuse reflections parametrized by random variables. As an example, analytical A-BRDFs are obtained for the Vector Based Scattering Model, and are validated against numerical Monte Carlo experiments. The analytical computation of A-BRDFs can be added to a standard acoustic ray tracing engine to obtain valuable data from each ray collision thus reducing significantly the computational cost of generating impulse responses.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"207-217"},"PeriodicalIF":0.0,"publicationDate":"2015-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70557744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we report the diameter dependent ultrasonic characterization of wurtzite structured InAs semiconductor nanowires at the room temperature. In this work, we have calculated the non-linear higher order elastic constants of InAs nanowires validating the interaction potential model. The ultrasonic attenuation and velocity in the nanowires are determined using the elastic constants for different diameters of the nanowires. Where possible, the results are compared with the experiments. Finally, we have established the correlation between the size dependent thermal conductivity and the ultrasonic attenuation of the nanowires.
{"title":"Diameter Dependent Ultrasonic Characterization of InAs Semiconductor Nanowires","authors":"M. Gupta, P. K. Dhawan, S. Verma, R. Yadav","doi":"10.4236/OJA.2015.54017","DOIUrl":"https://doi.org/10.4236/OJA.2015.54017","url":null,"abstract":"In this paper, we report the diameter dependent ultrasonic characterization of wurtzite structured InAs semiconductor nanowires at the room temperature. In this work, we have calculated the non-linear higher order elastic constants of InAs nanowires validating the interaction potential model. The ultrasonic attenuation and velocity in the nanowires are determined using the elastic constants for different diameters of the nanowires. Where possible, the results are compared with the experiments. Finally, we have established the correlation between the size dependent thermal conductivity and the ultrasonic attenuation of the nanowires.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"218-225"},"PeriodicalIF":0.0,"publicationDate":"2015-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70557756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-09-18DOI: 10.12677/OJAV.2015.33003
李元首, 陈宝, 张雪, 周国成, 谭啸, 姜涛
在飞机飞行噪声测量技术中，基于麦克风阵列的运动声源定位技术是飞行噪声测量的核心技术。本文利用对消声室内移测架携带的不同速度的运动声源进行定位分析，利用自研程序处理采集数据获得噪声源实际位置，通过结果对比分析，验证了运动声源定位的可行性，为飞机飞行噪声源定位奠定了基础。 In aircraft flight noise measurement technology, moving sound source localization based on mi-crophone array is the key technology of flight noise measurement. In this paper, the acoustic sources of different velocity in the acoustic chamber are analyzed. The actual position of noise source is obtained by using the program. Through comparison and analysis, the feasibility of moving sound source location is verified, which lays the foundation for the aircraft flight noise source location.
在飞机飞行噪声测量技术中，基于麦克风阵列的运动声源定位技术是飞行噪声测量的核心技术。本文利用对消声室内移测架携带的不同速度的运动声源进行定位分析，利用自研程序处理采集数据获得噪声源实际位置，通过结果对比分析，验证了运动声源定位的可行性，为飞机飞行噪声源定位奠定了基础。 In aircraft flight noise measurement technology, moving sound source localization based on mi-crophone array is the key technology of flight noise measurement. In this paper, the acoustic sources of different velocity in the acoustic chamber are analyzed. The actual position of noise source is obtained by using the program. Through comparison and analysis, the feasibility of moving sound source location is verified, which lays the foundation for the aircraft flight noise source location.
{"title":"消声室内运动声源定位研究 Study of Moving Sound Source Localization Array in Anechoic Room","authors":"李元首, 陈宝, 张雪, 周国成, 谭啸, 姜涛","doi":"10.12677/OJAV.2015.33003","DOIUrl":"https://doi.org/10.12677/OJAV.2015.33003","url":null,"abstract":"在飞机飞行噪声测量技术中，基于麦克风阵列的运动声源定位技术是飞行噪声测量的核心技术。本文利用对消声室内移测架携带的不同速度的运动声源进行定位分析，利用自研程序处理采集数据获得噪声源实际位置，通过结果对比分析，验证了运动声源定位的可行性，为飞机飞行噪声源定位奠定了基础。 In aircraft flight noise measurement technology, moving sound source localization based on mi-crophone array is the key technology of flight noise measurement. In this paper, the acoustic sources of different velocity in the acoustic chamber are analyzed. The actual position of noise source is obtained by using the program. Through comparison and analysis, the feasibility of moving sound source location is verified, which lays the foundation for the aircraft flight noise source location.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"03 1","pages":"17-22"},"PeriodicalIF":0.0,"publicationDate":"2015-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66177680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-09-18DOI: 10.12677/OJAV.2015.33004
冯媛媛, 徐彦彦, 倪赟, 吴亮
本文应用统计物理相变理论研究了局域化条件对宏观经济代理人基模型系统的振动动力学行为和相变现象的影响。通过数值模拟“MARK I型”的代理人基模型，分析了宏观经济系统的相变现象。文章引入了局域化条件来限制节点之间相互作用的范围并分析了由此产生的相变点位置的改变。我们进一步研究了不同策略调整的敏感系数的影响并分析了这些敏感系数的调整和局域化条件的耦合关系。本文从物理相变和同步的角度为驱动经济系统向好提供了一定的参考。 The fluctuations and phase transition phenomena in the macroeconomic agent-based model are investigated by using phase transition theory in statistical physics. Numerical simulations are performed on the MARK I agent-based model and typical discontinuous phase transitions are found. Localization conditions are introduced in the model so that the interactions between agents are limited geographically and the critical points in the phase transitions are analyzed. Moreover, the influence of the different values of price and production sensitivity parameters are studied as well as the coupling relations with the localization conditions. Our results may be potentially useful in providing a clue to improve the economic conditions from the viewpoint of phase transitions and synchronization in physics.
本文应用统计物理相变理论研究了局域化条件对宏观经济代理人基模型系统的振动动力学行为和相变现象的影响。通过数值模拟“MARK I型”的代理人基模型，分析了宏观经济系统的相变现象。文章引入了局域化条件来限制节点之间相互作用的范围并分析了由此产生的相变点位置的改变。我们进一步研究了不同策略调整的敏感系数的影响并分析了这些敏感系数的调整和局域化条件的耦合关系。本文从物理相变和同步的角度为驱动经济系统向好提供了一定的参考。 The fluctuations and phase transition phenomena in the macroeconomic agent-based model are investigated by using phase transition theory in statistical physics. Numerical simulations are performed on the MARK I agent-based model and typical discontinuous phase transitions are found. Localization conditions are introduced in the model so that the interactions between agents are limited geographically and the critical points in the phase transitions are analyzed. Moreover, the influence of the different values of price and production sensitivity parameters are studied as well as the coupling relations with the localization conditions. Our results may be potentially useful in providing a clue to improve the economic conditions from the viewpoint of phase transitions and synchronization in physics.
{"title":"局域化条件下宏观经济代理人基模型的相变 Phase Transition of the Localized Macroeconomic Agent-Based Model","authors":"冯媛媛, 徐彦彦, 倪赟, 吴亮","doi":"10.12677/OJAV.2015.33004","DOIUrl":"https://doi.org/10.12677/OJAV.2015.33004","url":null,"abstract":"本文应用统计物理相变理论研究了局域化条件对宏观经济代理人基模型系统的振动动力学行为和相变现象的影响。通过数值模拟“MARK I型”的代理人基模型，分析了宏观经济系统的相变现象。文章引入了局域化条件来限制节点之间相互作用的范围并分析了由此产生的相变点位置的改变。我们进一步研究了不同策略调整的敏感系数的影响并分析了这些敏感系数的调整和局域化条件的耦合关系。本文从物理相变和同步的角度为驱动经济系统向好提供了一定的参考。 The fluctuations and phase transition phenomena in the macroeconomic agent-based model are investigated by using phase transition theory in statistical physics. Numerical simulations are performed on the MARK I agent-based model and typical discontinuous phase transitions are found. Localization conditions are introduced in the model so that the interactions between agents are limited geographically and the critical points in the phase transitions are analyzed. Moreover, the influence of the different values of price and production sensitivity parameters are studied as well as the coupling relations with the localization conditions. Our results may be potentially useful in providing a clue to improve the economic conditions from the viewpoint of phase transitions and synchronization in physics.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"03 1","pages":"23-29"},"PeriodicalIF":0.0,"publicationDate":"2015-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66177729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This comparative study acquaints the reader with some properties of the eighth and tenth new shear-horizontal surface acoustic waves (SH-SAWs) propagating along the free surface of the magnetoelectroelastic (6 mm) medium. These new nondispersive SH-SAWs cannot exist when the electromagnetic constant α is equal to zero. The piezoelectromagnetic SH bulk acoustic wave and the surface Bleustein-Gulyaev-Melkumyan (BGM) wave are also chosen for comparison. The main problem of this report is the demonstration of the fact that the new waves can propagate slower than the BGM wave. This problem can be very important due to the fact that among the other known SH-SAWs the BGM wave can propagate significantly slower than the corresponding SH bulk acoustic wave. Two new SH-SAWs are analytically and graphically studied in dependence on the electromagnetic constant α. For the graphical study, two (6 mm) composites are used: BaTiO3– CoFe2O4 and PZT-5H–Terfenol-D. For the second composite it is solidly demonstrated that for small values of α, the eighth new SH-SAW cannot exist and its velocity starts with zero at some small threshold value of α rapidly reaching the BGM-wave velocity. This means that a weak magnetoelectric effect can dramatically slow down the speed of either new SH-SAW. As a result, the studied new SH-SAWs can be suitable for creation of new technical devices to sense the magnetoelectric effect. For the analytical study, extreme and inflexion points were evaluated in the velocities’ dependencies on the value of the electromagnetic constant α.
{"title":"Dramatic Influence of the Magnetoelectric Effect on the Existence of the New SH-SAWs Propagating in Magnetoelectroelastic Composites","authors":"A. Zakharenko","doi":"10.4236/OJA.2015.53007","DOIUrl":"https://doi.org/10.4236/OJA.2015.53007","url":null,"abstract":"This comparative study acquaints the reader with some properties of the eighth and tenth new shear-horizontal surface acoustic waves (SH-SAWs) propagating along the free surface of the magnetoelectroelastic (6 mm) medium. These new nondispersive SH-SAWs cannot exist when the electromagnetic constant α is equal to zero. The piezoelectromagnetic SH bulk acoustic wave and the surface Bleustein-Gulyaev-Melkumyan (BGM) wave are also chosen for comparison. The main problem of this report is the demonstration of the fact that the new waves can propagate slower than the BGM wave. This problem can be very important due to the fact that among the other known SH-SAWs the BGM wave can propagate significantly slower than the corresponding SH bulk acoustic wave. Two new SH-SAWs are analytically and graphically studied in dependence on the electromagnetic constant α. For the graphical study, two (6 mm) composites are used: BaTiO3– CoFe2O4 and PZT-5H–Terfenol-D. For the second composite it is solidly demonstrated that for small values of α, the eighth new SH-SAW cannot exist and its velocity starts with zero at some small threshold value of α rapidly reaching the BGM-wave velocity. This means that a weak magnetoelectric effect can dramatically slow down the speed of either new SH-SAW. As a result, the studied new SH-SAWs can be suitable for creation of new technical devices to sense the magnetoelectric effect. For the analytical study, extreme and inflexion points were evaluated in the velocities’ dependencies on the value of the electromagnetic constant α.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"73-87"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70557869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is shown that the estimation of nonlinear distortions in the various circuits based on the measurement of the ratio of the dispersion and correlation functions does not depend on the level of additive noise acting on the input (or output) of nonlinear circuit. The proposed theoretical method is confirmed by experimental measurements.
{"title":"The Dispersion Method for Estimating Non-Linearity of Electro-Acoustic Systems in the Presence of Additive Noise","authors":"V. Svet","doi":"10.4236/OJA.2015.53008","DOIUrl":"https://doi.org/10.4236/OJA.2015.53008","url":null,"abstract":"It is shown that the estimation of nonlinear distortions in the various circuits based on the measurement of the ratio of the dispersion and correlation functions does not depend on the level of additive noise acting on the input (or output) of nonlinear circuit. The proposed theoretical method is confirmed by experimental measurements.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"88-94"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70557917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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