scholarly journals A Virtual Instrument for Measuring the Piezoelectric Coefficients of a Thin Disc in Radial Resonant Mode

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4107
Author(s):  
Francisco Javier Jiménez ◽  
Amador M. González ◽  
Lorena Pardo ◽  
Manuel Vázquez-Rodríguez ◽  
Pilar Ochoa ◽  
...  
Keyword(s):  
Virtual Instrument ◽  
Iterative Procedure ◽  
Scientific Literature ◽  
Piezoelectric Materials ◽  
Ferroelectric Ceramic ◽  
Resonant Mode ◽  
Radial Mode ◽  
Frequency Range ◽  
Electrical Admittance

In this paper, we describe and present a Virtual Instrument, a tool that allows the determination of the electromechanical, dielectric, and elastic coefficients in polarised ferroelectric ceramic discs (piezoceramics) in the linear range, including all of the losses when the piezoceramics are vibrating in radial mode. There is no evidence in the recent scientific literature of any automatic system conceived and implemented as a Virtual Instrument based on an iterative algorithm issued as an alternative to solve the limitations of the ANSI IEEE 176 standard for the characterisation of piezoelectric coefficients of thin discs in resonant mode. The characterisation of these coefficients is needed for the design of ultrasonic sensors and generators. In 1995, two of the authors of this work, together with other authors, published an iterative procedure that allowed for the automatic determination of the complex constants for lossy piezoelectric materials in radial mode. As described in this work, the procedures involved in using a Virtual Instrument have been improved: the response time for the characterisation of a piezoelectric sample is shorter (approximately 5 s); the accuracy in measurement and, therefore, in the estimates of the coefficients has been increased; the calculation speed has been increased; an intuitive, simple, and friendly user interface has been designed, and tools have been provided for exporting and inspecting the measured and processed data. No Virtual Instrument has been found in the recent scientific literature that has improved on the iterative procedure designed in 1995. This Virtual Instrument is based on the measurement of a unique magnitude, the electrical admittance (Y = G + iB) in the frequency range of interest. After measuring the electrical admittance, estimates of the set of piezoelectric coefficients of the device are obtained. The programming language used in the construction of the Virtual Instrument is LabVIEW 2019®.

Effectiveness of a Modified Version of Airflow Therapy

1982 ◽  
Vol 47 (2) ◽  
pp. 160-164
Author(s):  
Glenn L. Falkowski ◽  
Arthur M. Guilford ◽  
Jack Sandler
Keyword(s):  
Success Rate ◽  
Scientific Literature ◽  
Future Research ◽  
Relative Importance ◽  
Differential Effectiveness ◽  
History Of ◽  
One Year ◽  
Main Components

Utilizing airflow therapy, Schwartz (1976) has claimed an 89% success rate with stutterers following treatment and an 83% success rate at one year follow-up. Such claims have yet to be documented in the scientific literature. The purposes of this study were: (a) to investigate the effectiveness of a modified version of airflow therapy; (b) to examine the relative importance of its two main components—passive airflow and elongation of the first vowel spoken. The speech of two adult male stutterers with a lengthy history of stuttering, was assessed with spontaneous speaking and reading tasks. Results indicated marked improvement in both subjects' speech on the reading task was maintained at follow-up 10 weeks later. For spontaneous speech, results were generally weaker and less durable. Effects of the two treatment components were cumulative and did not allow determination of any differential effectiveness between components. Implications of these findings were considered and directions for future research discussed.

Research of the Wood’s Alloy Crystallization Process Using the Acoustic Method

2021 ◽  
Vol 410 ◽  
pp. 855-861
Author(s):  
Aleksandr Yu. Yaroslavkin ◽  
Eugene A. Tyurin ◽  
Darya A. Melnikova
Keyword(s):  
Speed Of Sound ◽  
Crystallization Process ◽  
Ultrasonic Method ◽  
Single Pulse ◽  
Acoustic Method ◽  
The State ◽  
Sound Signal ◽  
Frequency Range ◽  
Wood’S Alloy

The article examines the process of crystallization of Wood alloy using the ultrasonic method. The dependence of the determination of the speed of sound in three aggregate states of the alloy (liquid, solid, transition (liquid-solid)) was derived. The relation-ship with the amplitude values of the sound signal, a single pulse in determining the speed of sound, as well as in determining the state of the alloy is carried out. The data obtained allow us to analyze the state of the alloy and the measurement time and the specified frequency range directly in the process of crystallization.

Method of Testing of Sound Absorption Properties of Materials Intended for Ultrasonic Noise Protection

2013 ◽  
Vol 38 (2) ◽  
pp. 191-195 ◽  
Author(s):  
Dariusz Pleban
Keyword(s):  
Sound Absorption ◽  
Free Field ◽  
Tone Burst ◽  
Mineral Wool ◽  
Frequency Range ◽  
Absorption Properties ◽  
Open Cell Foam ◽  
Properties Of Materials ◽  
Cell Foam

Abstract Efficient ultrasonic noise reduction by using enclosures requires the knowledge of absorbing properties of materials in the frequency range above 4 kHz. However, standardized methods enable determination of absorption coefficients of materials in the frequency range up to 4 kHz. For this reason, it is proposed to carry out measurements of the sound absorption properties of materials in the free field by means of a tone-burst technique in the frequency range from 4 kHz to 40 kHz at angles of incidence varying from 0° to 60°. The absorption coefficient of a material is calculated from the reflection coefficient obtained by reflecting a tone-burst from both a perfectly reflecting panel and a combination of this panel and the sample of the tested material. The tests results show that mineral wool and polyurethane open-cell foam possess very good absorbing properties in this frequency range.

Determination of Electric and Magnetic Properties of Commercial LTCC Soft Ferrite Material

2011 ◽  
Vol 8 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nelu Blaž ◽  
Andrea Marić ◽  
Goran Radosavljević ◽  
Nebojša Mitrović ◽  
Ibrahim Atassi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Frequency Range ◽  
Dispersion Parameters ◽  
Simple Method ◽  
Component Design ◽  
Microwave Engineering ◽  
Characterization Procedure

This paper offers an effective, accurate, and simple method for permittivity and permeability determination of an LTCC (low temperature cofired ceramic) ferrite sample. The presented research can be of importance in the fields of ferrite component design and application, as well as for RF and microwave engineering. The characterization sample is a stack of LTCC tapes forming a toroid. Commercially available ferrite tape ESL 40012 was used and standard LTCC processing was applied for the sample fabrication. For the first time, the electrical properties of a ferrite toroid sample of ESL 40012 LTCC ferrite tape is presented at various frequencies. The electrical properties of LTCC ferrite materials, permittivity and specific resistivity, are shown in a frequency range from 10 kHz to 1 MHz using the capacitive method. The hysteresis properties of this material are also determined. B-H hysteresis loops were measured applying a maximum excitation of 2 kA/m and frequencies of 50 Hz, 500 Hz, and 1000 Hz. Permeability is determined in the frequency range from 10 kHz to 1 GHz and a characterization procedure is divided in two segments, for low and high frequencies. Low frequency measurements (from 10 kHz to 1 MHz) are performed using LCZ meter and discrete turns of wire, while a short coaxial sample holder and vector network analyzer were used for the higher frequency range (from 300 kHz to 1 GHz). In addition, another important factor required for the practical design of devices is presented, the temperature variation of the permeability dispersion parameters.

Silicon Pillars as Resonators in an Acoustical Metamaterial

2014 ◽  
Author(s):  
Bernard Bonello ◽  
Rémi Marchal ◽  
Rayisa Moiseyenko ◽  
Yan Pennec ◽  
Bahram Djafari-Rouhani ◽  
...  
Keyword(s):  
Thin Plate ◽  
Lamb Waves ◽  
Mass Density ◽  
Resonant Mode ◽  
Ultrasonic Technique ◽  
Frequency Range ◽  
Negative Mass ◽  
Laser Ultrasonic ◽  
Compressional Mode ◽  
Bending Modes

We have investigated the propagation of Lamb waves in structures made of either an isolated resonant pillar or a set of pillars arranged in a line on a thin plate. The resonators as well as the plate are made of silicon. FEM computations show that two bending modes and one compressional mode are unambiguously identified in the frequency range of interest (0–10 MHz). We used a laser ultrasonic technique to map both the amplitude and the phase of the normal displacements on top of the pillars and at the surface of the sample. When the frequency is tuned to a resonant mode, either compressional or bending, the pillars vibrate 180° out-of-phase with respect to the Lamb waves, resulting in a negative modulus or negative mass density respectively.

scholarly journals STUDY OF PROCESSES OF PRESSURE AND IMPULSE FREQUENCY INFLUENCE ON PENETRATION OF LIQUIDS IN THE SAND SAMPLES

2016 ◽  
pp. 120-125
Author(s):  
M. Ya. Habibullin ◽  
R. R. Shangareyev
Keyword(s):  
Experimental Data ◽  
Oil Recovery ◽  
Pressure Fluctuations ◽  
Experimental Studies ◽  
Regression Equations ◽  
Linear Variation ◽  
Frequency Range ◽  
Impulse Frequency ◽  
Overburden Pressure

The article deals with the issues related to the hydrocarbon reservoirs oil recovery enhancement. It describes the bench laboratory experimental studies. The results obtained during determination of fluid leakage through the rock samples and the amount of absorption of pressure fluctuations at various regime parameters are presented. Using the experimental data the regression analysis was performed on the basis of which the qualitative correlations between factorial and resultant features were identified. Using the regression equations the graphic relations were constructed. It was found that with increasing the oscillation frequency of the fluid the amount of fluid passing through the sample of porous medium increased, with the highest value of q reached at the frequency range of 600 ... 1000 Hz. With increase in the oscillations penetration depth the absorption of the amplitude of the pressure fluctuations corresponds to the linear decrease, and with the overburden pressure increase the linear variation of absorption is distorted.

scholarly journals Raja yoga within the system of religious-ethical philosophy Of M. V. Lodyzhensky

2020 ◽  
pp. 64-90
Author(s):  
Oleg Viktorovich Solopov
Keyword(s):  
Critical Review ◽  
Scientific Literature ◽  
Critical Assessment ◽  
Special Role ◽  
The Novel ◽  
Ethical Philosophy ◽  
Knowledge Ontology ◽  
Comprehensive Study

This article is dedicated to examination of the characteristics of the doctrine of Raja yoga in interpretation Of M. V. Lodyzhensky. The goal consists in the analysis and reconstruction of the system of Raja yoga within the religious-ethical philosophy of the thinker. In the course of this research, the author resolves a number of problems: examines the system of primary elements of religious-ethical philosophy of M. V. Lodyzhensky; analyzes the sources that affected the formation of views of the philosopher upon Raja yoga; reveals main characteristics of the system of Raja yoga within Lodyzhensky’s philosophy; determines the peculiarities of religious-mystical practice of Raja yoga in the philosophy of M. V. Lodyzhensky; defines the role of Raja-yoga within the system of religious-ethical philosophy of the thinker. The novelty lies in determination of the novel in comparison to the existing in scientific literature categories of M. V. Lodyzhensky’s philosophy and their analysis in the context of system of fundamental sections of philosophical knowledge (ontology, theology, anthropology, epistemology, axiology, ethics); as well as in comprehensive study of the system of Raja yoga in interpretation Of M. V. Lodyzhensky and determination of its role within the structure of his philosophy. It is established that the “core” of the system of religious-ethical philosophy of M. V. Lodyzhensky is the ethics develop ethics and axiology of Hesychasm developed by him. It is proven that the system of metaphysical categories and ideas of the thinker is of synthetic nature and leans on various cultural trends and traditions. The article demonstrates that special role within the system of Lodyzhensky’s philosophy is played by the apologetics of Hesychasm that implies critical review of the non-Christian mystical practices, among which is the examination of Raja yoga. The author underlines the uniqueness of interpretation of Raja yoga in the philosophy M. V. Lodyzhensky, as well as provides critical assessment to his interpretation of the system of Raja yoga.

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