This article outlines the rationale and relevance of the theme of its relevance in a real production. A brief description of the object of research , as well as the causes of the defects of the object. Later in the article describes the methods used to conduct the study , describes the applicable non-destructive and destructive methods . Describes the results obtained in the course of work , methods of mathematical processing , obtained correlations . The graphs dependencies. Next, a method developed that allows for quality control.
Keywords: granite, nondestructive testing, destructive testing, careers, ultrasound, natural frequency, correlations
With the growing fleet's increasingly acute problem arises safety and reliability their exploitation as a result of this increase in productivity and accuracy of their technical diagnostics. Urgent task to further improve diagnosis for vehicles is to develop new methods and algorithms highlight the dominant component of the information in relation to a wide class of vehicles. The methods joint time-frequency and wavelet analysis. To isolate the dominant component of the information proposed to use the method of wavelet decomposition. Using vibro acoustic registration nodes vehicles funds allowed to receive signals carrying information about the defects of individual units of vehicles. The proposed decoding algorithms signals have high reliability, allow technical inspection, subsequent monitoring of the technical state of the vehicle. Using vibroacoustic registration of vehicles allowed nodes receive signals carry-ing information about the defects of individual units of vehicles. The proposed decoding algorithms signals have high reliability, allow technical inspection, subsequent monitoring of the technical state of the vehicle.
Keywords: vehicle, vibroacoustic diagnostics, dominant information, time-frequency analysis, wavelet analysis
Vocal speech is a random process. Taking into account the fact that the main characteristics of a singing voice vary with time, in the article vocal speech is studied as an acoustic nonstationary random process. To describe this process we should calculate one of its informative parameters – the autocorrelation function. The findings show that there are some differences between the autocorrelation functions for professional and nonprofessional singers. This helps to make a quantitative assessment of a singer’s professionalism which, alongside with a vocal teacher’s subjective assessment, can present an objective view on a singer’s voice and provide a good basis for optimization of academic voice training. Moreover a teacher does not have to be technically educated because this quantitative assessment is presented in diagrams which are quite easy to assess visually. It is especially important to consider when we use the given voice assessing method in music schools, colleges and universities.
Keywords: Vocal speech, acoustic signal, nonstationary random process, autocorrelation function, the maximum autocorrelation interval, quantitative assessment
Calculation of acoustical pressure in the main water pipeline filled with water is in-process carried out, at affecting of cavitation processes. Calculation is lead by means of interactive system MatLab
Keywords: Acoustics, pressure, extending, wave, the main water pipeline, cavitation
Relationships and dependences between parameters of an ultrasonic pulse and water tube structure are in-process observed
Keywords: ultrasound, monitoring, structure, extending, water supply systems
Features of sampling of the piezoceramic transducer for the arrangement of structural monitoring of water supply systems are in-process observed and calculations of basic performances of the sensing transducer (material PZT-5A) are led
Keywords: piezoceramic transducer, ultrasound, monitoring, structure, extending, water supply systems
The device for energy takeoff in water systems on a bottom piezoceramic a device entrained in a water stream is in-process observed. The water stream, contacting with piezoceramic a device, calls it oscillations and potential emersion on plates.
Keywords: piezoceramic a device, piezooscillator, monitoring, structure, a water stream, water supply systems
The intelligence system of monitoring of technological parameters of the water pipeline is in-process observed, allowing to lead an estimate of reliability of water supply systems and optimisation of plots of repair
Keywords: Intelligence system, monitoring, structure, technological parameters, the water pipeline, reliability, repair
An analysis of new methods and means for a mesurement of parameters of piezoelectric ceramic elements and materials is carried out. These methods and means are based on a digital principle of the construction of devices. An impuls with a linear frequncy modulation therein is used as an signal for exciting. Results of experimental studies on this subject are represented for discussion.
Keywords: piezo ceramic element, piezo, methods and means of measurement, digital signal processing
A voice activity detector (VAD) is a device, which analyses a speech signal and generates the signal corresponding to the period containing only noise. In the present work is offered VAD, which increases the probability of correct detection the presence or absence of human speech.
The correct detection begins with SNR 7-10 dB. The quality of derived speech signal remains the same.
Keywords: voice activity detection, voice activity detector, VAD, silent interval detection, speech, speech signals
The technique of space-time processing of acoustic signals with the use a convolution algorithm the purpose of application of which is the spatial positioning of the virtual soun sourse (auralization) is com=nsidered in this article. Also the reverberation chatacteristics of a modeled acoustic environment are take into consideration.
Keywords: auralization, HRTF, artificial reverb, room simulation, convolution algorithm, impulse response convolution, impulse response synthesis, dynamic convolution, complex filtering
An estimate of the frequency discretization interval was obtained in solving diagnostic problems of a piezoceramic element by means of different methods based on measuring the active component of conductivity in a number of discrete points. This allows avoiding precision loss and, at the same time, reducing the number of measurements and computational operations.
Keywords: Piesoceramic element, Q-factor, active component of conductivity
We study the problems in the propagation of acoustic waves of a sound range near the boundaries of media. The features of the wave processes occurring at the water-air interface, due to the influence of inhomogeneous waves. Considered in detail the properties and parameters of an inhomogeneous plane wave. The mathematical calculations of the transmission coefficients L.M. Brekhovskikh for spherical and cylindrical waves through this boundary, allowing to take into account the contribution of inhomogeneous components. It is shown that than the frequency of radiation of a source is lower and the closer it is located to water-air interface, the acoustic transparency of this border is higher. Study of the dependence of the transmission coefficient of the water-air interface at low frequencies can have important consequences in a number of fundamental and applied problems. Increase the transparency of the interface requires a reassessment of the feasibility of acoustic communication from water in the air, the detection of underwater sources without dipping into the water and acoustic monitoring of the physical processes occurring in the water.
Keywords: Inhomogeneous plane wave, water-air interface, transmission coefficient, wavelength, spherical wave, acoustic impedance.
A hybrid reverberation algorithm is offered in this article. This algorithm is using both a convolution section in which a convolution with an inmpulse response of a real acoustic room is being implied and a mathematical reverb model. Also an algorithm for generating impulse responses of optional rooms is also offered in the following article. The algorithm efficiency calculation is specified in the article. Thia reverberation algorithm is a part of a bigger complez auralization algorithm where it is being used coherently with an HRTF-based algorithm in order to simulate a real acoustic environment
Keywords: artificial reverb, room simulation, convolution algorithm, impulse response convolution, impulse response synthesis, dynamic convolution, complex filtering
Assesses the performance of common and new methods for determining the parameters of piezoelectric elements using hardware and software developed by means of LabView.
Keywords: control of piezoceramic elements, methods for determining the parameters, LabView, production, productivity.
Solution for high-speed video transmission in hydroacoustic channel by amplitude modulation with orthogonal subcarriers is specified. Results of method experimental check are presented. Discussed method is doppler-tolerant and can be realized in many common DSPs.
Keywords: hydroacousitcs, video transmission, amplitude modulation
Is considered non-stationary axisymmetric problem for fine round bimorph plate under the action of the top end surface of the normal stresses, being an arbitrary function of radial coordi-nates and time. On the basis of the theory of Tymoshenko by the method of finite integral transformations built a a new solution for the electroelasticity system stepwise variable thickness and stiffness. The obtained relations allow to investigate the stress-strain state and the potential difference between external electrodes bimorph elements.
Keywords: task reverse piezoelectric effect, thin bimorph plate, axially symmetric dynamic load
The article gets application multi-element piezoelectric transducers for ultrasonic high-speed flaw detection on railway tracks. The processing algorithm of echo-signals from multi-element piezoelectric transducers was offered to get additional information about defect location to apply solution considering risk level more validly and to increase crack detection probability. The obtained algorithm was realized as software package. A set of experiments was completed for fourth-elements inclined piezoelectric transducer on a standard pattern for various positions to verify the processing algorithm. The experiment has shown that the echo-signals behavior allows to use the obtained algorithm for multi-element transducers at the high-speed flaw detection. Also it has emerged that the echo-signal shape at one element of piezoelectric transducer strongly depends on refracting prism geometry and relation position elements on prism.
Keywords: multielement piezoelectric transducers; ultrasonic methods; echo-signal; high-speed flaw detection
Now nanotechnologies are one of perspective methods of diagnostics in medical practice. Nanoparticles can be used as contrast agents for medical ultrasonic introscopy due to their adhesion to tumor cells and bacteria. The mathematical model of the laser excitation of acoustic signals in a liquid medium with the presence of the nanotubes was developed and numerically studied. Increasing of the level of photo acoustic signal was shown.
Keywords: Opt acoustic effect, nanotubes, and model
This paper discusses the problem of controlling the characteristics of sonar multibeam receiver antennas. Hydro acoustic means, such as side-scan sonar, profiler, sonar, multibeam sonar, are used extensively for remote determination of the parameters of media for environmental management. In the article the technique of controlling the phase-frequency characteristics of the receiving antennas multibeam echoes sounders. The study method allows the measurement of the phase-frequency characteristics of antennas in a hydro acoustic tank which size is less than length of a near field of the reception aerial.
Keywords: Conservancy, multibeam echo-sounder, seabed research, underwater acoustic
In operation the case of distribution of an ultrasonic wave in a water pipe located in the dense ground and subject to activity of radial pressure of a ground is viewed.
Keywords: acoustics, monitoring, ground, distribution, wave, water pipe
The description of electrodynamic model of the receiver of ultrasonic radiation on the basis of a piezoelectric is presented. Modelling was conducted with use of a method of electrodynamic analogies. The given method allows to apply an accessible arsenal of computational methods of electric circuits as analogues of the composite dynamic systems which class systems of monitoring of waterpipes concern.
Keywords: acoustics, the control, piezoelectric transducer, the water pipeline.
In operation the case when the cylindrical pipe is not completely filled by water is viewed, the ultrasonic radiator is located on a shell of a water pipe. It is shown, that for the given case, it is expedient to view the symmetrical and assymetric modes of distribution of an ultrasonic wave.
Keywords: acoustics, emitter, wave, water pipe
At the organization of system of monitoring of water supply systems, the important problem is definition of resistant to work of the sender and the receiver of an acoustical wave executed on the basis of piezoelectric transducers.
Keywords: acoustics, the control, piezoelectric transducer, the water pipeline.
In operation the case when the radiant of an acoustic signal is in a composite cylindrical pipe is viewed. It is shown, that at transition of a pipe of one diameter in a pipe of other diameter, it is expedient to apply modal representation of an acoustic wave to each site of a pipe.
Keywords: acoustics, the control, diameter, waterpipe