KEYWORDS: Ultrasonics, Mathematical modeling, Ultrasonography, Receivers, Temperature metrology, Acoustics, Process control, Wave propagation, Signal processing, Signal attenuation
The aim of the research is to improve the technical parameters of ultrasonic meters by using the phenomenon of resonance and standing wave. The basis of the resonance method is the using standing acoustic waves arising in the medium due to the interference of the incident and reflected acoustic waves. The paper proposes a mathematical model of the ultrasonic resonance method for measuring parameters of liquid and gaseous media, which can be used for measuring control of parameters such as density, temperature, thickness, flow velocity, and others. To test the adequacy of the proposed model of ultrasonic wave propagation, its computer simulation and experimental studies were carried out. The air was chosen as the test medium (temperature 20° С, velocity 343m/s, atmospheric pressure 1atm). The time diagrams of the signal at the receiver for a distance of 34.3mm, when the resonance condition was satisfied, and for a distance of 34.73mm, when the ant resonance condition was satisfied, were modeled according to the proposed mathematical model. The dependence of the amplitude of the signal at the receiver is given for signal frequencies of 170–20kHz with a transmitter-to-receiver distance of 35.85mm and a sound speed of 340.8m/s. The simulation results confirm the adequacy of the purposed mathematical model. This allows proposing a new class of self-oscillating ultrasonic methods for measuring and control of medium parameters. The block diagram and the principle of operation of the auto-oscillating ultrasound meters for measuring the thickness, and gas temperature of test objects are described.
The paper proposes a new method for calculating the weight coefficients of an artificial neural network in the systems of technical diagnostics of hydro aggregates, in which it is proposed to use the coefficients of correlation between vibration signals in spatially distributed points of a hydro aggregate. A mathematical model and algorithm for calculation of weight coefficients of an artificial neural network are developed. The expediency of use of wavelet transformation of time realizations of a vibration signal is shown, as a result of which the received vibration signal is divided into amplitude-frequency-time spectrum, which leads to increase its informativeness. Experimentally confirmed the presence of strong inter-correlation links between spatially distributed points of the hydro aggregate and their dependence on the nature and place of application of disturbing forces. The dependence of the correlation coefficients on the load of the hydro aggregate and the water pressure in the reservoir is established. The obtained results can be considered as an experimental confirmation of the expediency of using the proposed method for calculating the weight coefficients of an artificial neural network.
The paper studies radiomeasuring device with a frequency output signal based on a pyroelectric primary converter. The frequency converter of optical radiation is designed using a bipolar transistor structure with a negative differential resistance and a pyroelectric sensitive element. A dynamic mathematical model of the frequency radiomeasuring converter has been developed which enables to determine the value of voltage or current at any point in the circuit at any particular time under the action of optical radiation in the region of infrared light. Analytical expressions for the transfer function and the sensitivity equation have been obtained. The sensitivity of the developed device is 20 kHz/μW/cm2.
Proposed is a new noncontact method for measurement of axial displacement of electric machine’s rotor in real-time mode and developed is the structural pattern of measurement procedure to implement this.
A tool has been proposed that allows rapid analysis to measure relative humidity during experimental research on the decomposition of municipal solid wastes for the development of highly efficient garbage trucks as the main link in the structure of machines for the collection and primary processing of municipal solid wastes. The structural scheme of the device for measuring relative humidity is given. A block diagram of the microcontroller control program algorithm for measuring relative humidity has been developed. The main characteristics of the proposed device are given. Calibration and experimental tests to measure the relative humidity of municipal solid wastes were conducted. As a result of the experimental studies presented in the work, the reliability of the measured parameter is confirmed.
The article presents the mechatronic hydraulic drive circuit, designed in Vinnytsia National Technical University. For the mechatronic hydraulic drive a linear mathematical model is developed. The influence of the mechatronic hydraulic drive parameters on static, dynamic and energy characteristics is investigated. Optimization parameters and their variation ranges are determined. In the process of parametric optimization such combination of parameters has been found, which provides optimal values of the mechatronic hydraulic drive characteristics.
KEYWORDS: Mechanics, Magnetism, Transformers, Sensors, Ferromagnetics, Chemical species, Transducers, Mathematical modeling, Magnetic sensors, Control systems
Developed was a new method of control of mechanic rigidity in assemblies of hydropower units that allows a real-time control of technological process, and proposed was the design for a primary measuring transducer of mechanic intensity as a component of the control method proposed, with its transformation equations obtained.
In the paper is suggested new noncontact method of temperature measurement based on the phenomenon of the
luminophor temperature decreasing, is developed the construction of the primary measurement transformer, that
implements suggested method, and got its transformation equation.
The paper proposes a method of conversion additive and multiplicative errors, mathematical models are obtained by a Taylor expansion of the transformation equations used measuring instruments in the instrumental component of the measurement uncertainty.
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