Ultrasonic Measurement Method Research Articles

Ultrasonic methods and their implementation for evaluating porous materials

In this article application of direct and indirect ultrasonic methods for evaluating and measuring porous materials are reviewed. Ultrasonic waves, due to their physical properties and wide frequency range can successfully be applied when evaluating the porosity of materials. Ultrasonic methods have many advantages when comparing them with other, non-acoustic measurement methods, which are also briefly reviewed in this article. We examine application of the proposed acoustic echolocation method when evaluating porous materials directly and indirectly. The possibilities to apply Lamb waves for evaluation of porous structures are also examined. The application of ultrasonic echolocation measurement method to evaluate porous structures indirectly is presented in depth, along with the process description and various possible implementations. The basic principle along with advantages and shortcomings of such methods are explained. Physical-mechanical properties of porous materials are also described, along with mathematical equations, which are necessary for their theoretical analysis. The ability to determine porosity of various materials is necessary to insure the quality of the final product. We also present a working real-world system, which implements an indirect ultrasonic porosity evaluation method. For indirect porosity determination, we use a very accurate ultrasonic echolocation-based distance meter. Block diagram for such unit is presented. The most important component in the acoustic porosity evaluation system is the electro-acoustic transducer. We describe the most suitable transducers for use in this case, along with acoustic antennas constructed using such transducers. Antennas, designed for measurements in air, consist of transducers vibrating in a flexural mode, which give the best possibility to match acoustic impedances between air and the transducer. Specific type of transducers for acoustic antennas is described, along with their schematic diagrams. The necessary expressions for calculating radiations patterns are also supplied. Schematic diagrams of actual antennas, along with their directivity patterns are presented. A method for eliminating peripheral radiation of these antennas is also described.http://dx.doi.org/10.5755/j01.u.66.4.1021

Application of ultrasonic measurement method for investigation of green ceramic tiles

High quality requirements are established for ceramic tiles manufacturing, because they must be weather-resistant, durable, in general, hard, wear and corrosion resistant and also can withstand high stresses at elevated temperatures. One of the possible control methods of the manufactured tiles quality is ultrasonic method based on measurement of ultrasonic wave propagation speed. However, measurements of ultrasonic wave velocity in green ceramic tiles with an uneven surface are difficult. Therefore attention must be directed to the individual measurement problems of this method, which are the following: uneven surface of the inspected tile; necessity of a dry acoustic contact, non-uniform elastic properties of the tested tile.http://dx.doi.org/10.5755/j01.u.66.4.1023

Research On The Performance Of The Ultrasonic Measurement System Of The Tree Canopy Volume

Abstract Variable-rate spraying technology can change the application rate by the target information. And the tree canopy volume was a very important target information. An ultrasonic measurement method of canopy volume was presented, and an ultrasonic measurement system of canopy volume was developed. The average of Wheaton and Albrigo manual measurement values was defined as the manual measurement values in this paper.150 peach trees having different canopy volumes were selected to as the experimental objects. Experiment results indicated that the ultrasonic measurement system had high stability (R2=0.968, Std. Error of the Estimate was 0.061719), the manual measurement method had high stability(R2=0.973, Std. Error of the Estimate was 0.060214), and the manual measurement values and the ultrasonic measurement values were in a good agreement(R2=0.968, Std. Error of the Estimate was 0.065314), that is the ultrasonic measurement system had high precision.

Biofuel ethanol adulteration detection using an ultrasonic measurement method

Hydrous ethanol is a worldwide used biofuel. According to Brazilian regulations, the concentration of ethanol in hydrous ethanol can be accepted at a maximum concentration of 93.8% and a minimum of 92.6% by mass. The aim of this study is to identify the possible changes in hydrous ethanol fuel using ultrasonic attenuation and propagation velocity. The experiments were performed in the Laboratory of Ultrasound of the Brazilian National Institute of Metrology (Inmetro). The experiments and uncertainties in the methodology were evaluated according to the Guide to the Expression of Uncertainty in Measurement, JCGM 100:2008. The test samples used in this study were mixtures of ethanol and water with ethanol concentrations varying from 89.84% to 93.71% by mass; and a commercial fuel ethanol bought from a local distributor. The correlation coefficient between ethanol concentrations and ultrasonic propagation velocity was 0.99 (in modulus), and the maximum combined uncertainty was 0.60ms−1. Considering attenuation, the correlation coefficient was 0.97, and the maximum combined uncertainty was 0.085dBcm−1. However, its signal is not stable resulting an unreliable parameter. Within the tested concentration range, the highest concentration that is statistically different (p<0.002, α=5%) from 92.60% is 92.25%, considering propagation velocity as parameter. To validate the methodology, a commercial ethanol fuel was tested using the proposed method as well as the gas chromatography analytical method (gold standard). Result was statistically identical for propagation velocity when compared to the gold standard.

Ultrasonic monitoring of lubricating conditions of hydrodynamic bearing

The performance of a hydrodynamic bearing is illustrated by the lubricating conditions which transfer from ones to another when working condition is changed. The thickness of lubricant film is the key parameter of lubricating conditions. The lubricating conditions of hydrodynamic bearing can be monitored by the measured film thickness and the relationship between them. For thin lubricant film layers less than ultrasonic wavelength, the spring model method is applied to measure the film thickness. The proportion of the ultrasound reflected from film layer, depended on the film stiffness, is determined and then can be readily converted to the film thickness. For the thicker films ranging from several microns to tens microns, ultrasonic resonance method was employed. An adaptive measurement algorithm is presented to automatically choice appropriate ultrasonic measurement method according to the different lubricating stage. All the range of lubricant film thickness of a hydrodynamic bearing can then be measured by the automatic selection of spring model and resonance methods. Simulation device of lubricant film layers with PZT positioning stage is designed to verify the accuracy of the adaptive measurement algorithm. Hydrodynamic bearing experimental setup is used to generate varies of lubricating condition by changing the shaft speed, radial direction loading force, and lubricant temperature. The lubricating condition of hydrodynamic bearing is then evaluated according to the measured lubricant film thickness and the working conditions.

Research on High-Accuracy Low-Power Ultrasonic Flow Measurement and Instrument

In order to solve the problem of low accuracy and high power consumption, A new ultrasonic flow measurement method was proposed in this paper. With this method, the influence of the delay-time in the circuit was eliminated,the temperature of fluid was compensated automaticly and the accuracy of the flow measurement was improved. The ultrasonic flow-meter was designed with the micro-power timing chips TDC-GP2 and MSP430F435, which reduced the power consumption effectively. The experimental results showed that the accuracy of the ultrasonic flow-meter was 1.5% and the average operating current was lower than 35uA.

Applying ultrasonic echolocation-based measurement method to increase the accuracy of leveling instruments

Current mechanical, laser and electronic leveling instruments are sometimes not accurate enough to be used for determining either vertical or horizontal level for level-critical applications. By using an ultrasonic echolocation-based distance meter it is possible to design very accurate leveling instruments for a wide range of applications. This article overviews the accuracy of current leveling instruments and compares it with the achievable accuracy of the proposed leveling devices. Level determination of horizontal and vertical surfaces using mechanical devices is explained. By combining the ultrasonic distance determination method with the mechanical level determination methods, very precise leveling instruments can potentially be created. Some exemplary designs of such leveling instruments are presented. In addition, basic operating principles of an ultrasonic echolocation-based distance measurement device are presented, along with sources of measurement errors of such devices. Solutions for eliminating measurement errors are discussed. Since accuracy is the top priority, we suggest creating an isolated operating environment for acoustic measurements. A practical example of using a leveling device with implemented ultrasonic measurement method is presented along with measurement results.http://dx.doi.org/10.5755/j01.u.66.1.261

Calorimetric method for measuring high ultrasonic power using water as a heating material

The present study shows the calorimetric method for measuring high ultrasonic power using water as the heating material. In recent years, at the National Metrology Institute of Japan (NMIJ), an ultrasonic power primary standard of from 1 mW to 15 W has been established by the radiation force balance (RFB) method. Conventionally, the RFB method is widely used for ultrasonic power measurement, but this method is not suitable for very high power measurement due to thermal damages to the absorbing targets. High power ultrasonic standards, however, are being required by medical HITU measurements and in the sonochemistry industry. In order to meet these requirements, we have started to develop an ultrasonic power standard between 15 W and 200 W. Our final goal is an ultrasonic power standard of up to 500 W. The calorimetric method is an alternative ultrasonic power measurement method to the RFB method. We have adopted this method and use water as the heating material. Water has excellent features as a standard material, because the physical properties of water are well known. In the present study, we present an experimental system and the results for an ultrasonic power standard of up to 100 W. The measured ultrasonic power agreed well with the NMIJ primary standard up to 25 W.

A broadband spectroscopy method for ultrasonic wave velocity measurement under high pressure

A broadband spectroscopy method is proposed to measure the ultrasonic wave phase velocity of Z-cut quartz under high pressure up to 4.7 GPa. The sample is in a hydrostatic circumstance under high pressure, and we can get longitudinal wave and shear wave signals simultaneously in our work. By fast Fourier transform of received signals, the spectrum and phase of the received signals could be obtained. After unwrapping the phase of the received signals, the travel time of ultrasonic wave in the sample could be obtained, and the ultrasonic wave phase velocity could also be resolved after data processing. The elastic constant of measurement under high pressure is also compared with previous studies. This broadband spectroscopy method is a valid method to get ultrasonic wave travel parameters, and it could be applied for elasticity study of materials under high pressure.

Effect of strain hardening and strain softening on welding distortion and residual stress of A7N01-T4 aluminum alloy by simulation analysis

The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress, plastic strain and welding distortion of A7N01-T4 aluminum alloy was studied by finite simulation method. The simulation results show that the weld seam undergoes strain hardening in the temperature range of 180–250 °C, however, it exhibits strain softening at temperature above 250 °C during welding heating and cooling process. As a result, the strain hardening and strain softening effects counteract each other, introducing slightly influence on the welding residual stress, residual plastic strain and distortion. The welding longitudinal residual stress was determined by ultrasonic stress measurement method for the flat plates of A7N01-T4 aluminum alloy. The simulation results are well accordant with test ones.

Intra-Observer Variability of Longitudinal Displacement and Intramural Shear Strain Measurements of the Arterial Wall Using Ultrasound Noninvasively in vivo

Using a recently developed high-resolution noninvasive ultrasonic method, we recently demonstrated that the intima-media complex of the common carotid artery show a bidirectional multiphasic longitudinal displacement of the same magnitude as the diameter change during the cardiac cycle. The longitudinal movement of the adventitial region was smaller, thus, we identified shear strain and, thus, shear stress, within the arterial wall. The aim of this study was to evaluate the intra-observer variability of measurement of the longitudinal displacement of the intima-media complex and the intramural shear strain of the common carotid artery in vivo using the new ultrasonic method. The evaluation was carried out by comparing two consecutive measurements on the common carotid artery of 20 healthy human subjects. According to the method of Bland Altman, we show that the systematic and random differences for the different phases of movement are acceptable in comparison to the measured displacement and no significant differences between the two measurements could be detected ( p > 0.05 for all measured parameters). The coefficient of variation (CV) for measurement of the different phases of movement was ≤16%, including short-term physiologic variations. The higher variability in the measurement of the intramural shear strain (CV = 24%) has several explanations, which are discussed. In conclusion, this study shows that the present first ultrasonic method for high-resolution measurement of the longitudinal movement of the arterial wall is reliable and satisfactory for the further research of the longitudinal movement of the arterial wall in vivo. Further studies on the longitudinal movement of the arterial wall are important for developing an improved understanding of the physiology and the pathophysiology of the cardiovascular system. (E-mail: magnus.cinthio@elmat.lth.se)

Ultrasonic Attenuation Measurement Method for Characterization of Clay Particles Mass Fraction in Dilute Suspension.

Article Ultrasonic Attenuation Measurement Method for Characterization of Clay Particles Mass Fraction in Dilute Suspension. was published on December 1, 2009 in the journal High Temperature Materials and Processes (volume 28, issue 6).

The two coupling fluids method for ultrasonic velocity measurement. Application to biological tissues

Measuring the ultrasonic velocity in soft materials, especially in biological tissues, is never easy. One of the main issues is that the thickness of the sample under test is badly defined. From the time-of-flight measurement method, uncertainties in the thickness induce important uncertainties in experimental results. This implies that the ultrasonic velocity is often a poor criterion when it could be a good one. This paper introduces a new method to measure the ultrasonic velocity in soft materials without knowing the sample thickness The main idea of this method is to use two different coupling media to make two relative time-of-flight measurements. The comparison of these two measurements gives the ultrasonic velocity in the sample under test. Furthermore, this comparison can give the local thickness of the sample. The uncertainty calculations show that the effect on the thickness is drastically reduced by using this new ultrasound method. This method is validated on a reference sample (silicone). Before conclusion, some experimental results obtained with mouse skin samples are presented.

Influence of sulfuric acid bath on morphological structure and mechanical properties of poly(p‐phenylene‐1,3,4‐oxadiazole) fibers

AbstractPoly(p‐phenylene‐1,3,4‐oxadiazoles) (p‐PODs) spinning solution was prepared by one‐step polycondensation, and p‐POD fibers were obtained by wet spinning method using dilute sulfuric acid as coagulation bath. The morphology and mechanical properties of p‐POD fibers under different coagulating conditions, such as bath concentration and temperature, were qualitatively and quantitatively studied by microscopes, ultrasonic orientation measurement, WAXD, and other traditional methods. The microscopic observation indicated that the p‐POD fibers were of three‐layer structure which consisted of outer skin, inner skin, and the core. The skin‐core structure and surface feature of the fibers were greatly affected by the coagulating conditions. At the same time, the results of WAXD and ultrasonic orientation measurement demonstrated that the crystallinity and orientation of the fibers also varied with the change of bath conditions. The tests of mechanical properties showed that the tensile strength, elongation at break, and maximum draw ratio of the p‐POD fibers were determined by their solid‐phase structures, which were largely influenced by coagulation conditions. According to the structure analysis and the mechanical tests, the optimal coagulation parameters were chosen to obtain p‐POD fibers with denser and more regular structure and better mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

A new measurement method for ultrasonic surface roughness measurements

This study proposes the application of Doppler-based ultrasonic method to surface roughness measurements. The fabricated prototype measures the slope of the under-test surface at small holes to evaluate the roughing parameters and this makes for more precise measurement. The device comprises an ultrasonic transmitter emits sound pulses that travel across to the under-test surface. The reflected wave is separated into many weak sounds, a few of which are received by the receiver. The Doppler effect caused the frequency of the received wave to be shifted with respect to the surface roughness at the reflecting point. The relationship between the Doppler shift and the roughing slope is mathematically analyzed. Compared to the transit-time based techniques, the dependency of the sensor on the sound speed in air is decreased by a factor of 2 and therefore a more precise measurement is achieved. The fabrication of a prototype device and experimental verification of the analytical results are reported.

Viscosity measurement of Newtonian liquids using the complex reflection coefficient

This work presents the implementation of the ultrasonic shear reflectance method for viscosity measurement of Newtonian liquids using wave mode conversion from longitudinal to shear waves and vice versa. The method is based on the measurement of the complex reflection coefficient (magnitude and phase) at a solid-liquid interface. The implemented measurement cell is composed of an ultrasonic transducer, a water buffer, an aluminum prism, a PMMA buffer rod, and a sample chamber. Viscosity measurements were made in the range from 1 to 3.5 MHz for olive oil and for automotive oils (SAE 40, 90, and 250) at 15 and 22.5 degrees C, respectively. Moreover, olive oil and corn oil measurements were conducted in the range from 15 to 30 degrees C at 3.5 and 2.25 MHz, respectively. The ultrasonic measurements, in the case of the less viscous liquids, agree with the results provided by a rotational viscometer, showing Newtonian behavior. In the case of the more viscous liquids, a significant difference was obtained, showing a clear non-Newtonian behavior that cannot be described by the Kelvin-Voigt model.

Application of Air-Coupled Ultrasonic Techniques Using Carbon/Carbon Composites

Carbon/carbon(C/C) composite materials have obvious advantages over conventional materials, which consist of carbon fibers embedded in a carbon matrix. It’s low density, high thermal conductivity and excellent mechanical properties at elevated temperatures make it an ideal material for aerospace applications especially aircraft brake disks. Because of permeation of coupling medium such as water, it is desirable to perform contact-less nondestructive evaluation to assess material properties and part homogeneity. In this work, a C/C composite material was characterized with non-contact and contact ultrasonic methods using automated acquisition scanner. . Due to the acoustic impedance mismatch found between most materials and air, a major limitation for air-coupled transducers, through-transmission mode was performed. Especially ultrasonic images and velocities for C/C composite disk brake were measured and found to be consistent to some degree with the non-contact and contact ultrasonic measurement methods. 400 kHz frequency through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the inhomogeneity in material property. Non-contact measured results were compared with those obtained by the motorized system using contact drycoupling ultrasonics and through transmission method in immersion. Results using a proposed peak-delay measurement non-contact method corresponded well to the ultrasonic velocities of the contact pulse overlap method.

Two coupling media method for ultrasonic velocity measurement in biological tissues

Measuring the ultrasonic velocity in soft materials, especially in biological tissues, is never easy. One of the main problems is that the thickness of the sample in test is badly defined. From time-of-flight measurement method uncertainties in the thickness induce important uncertainties in experimental results. This causes that the ultrasonic velocity is often a poor criteria whereas it could be a good one. This paper brings a new method to measure the ultrasonic velocity in soft materials without knowing the sample thickness The main idea of this method is to use two different coupling media for making two relative time-of-flight measurements. The comparison of these two measurements gives the ultrasonic velocity in the sample in test. Furthermore, this comparison can give the local sample thickness of the sample. The uncertainty calculi show up that the effect on the thickness uncertainties is drastically reduced by using this new ultrasound method. This method is validated on reference samples, in silicon. Before concluding, some experimental results obtained with mouse skin samples are presented.

Air-coupled non-contact mechanical property determination of drug tablets

A non-contact/non-destructive technique for determining the mechanical properties of coated drug tablets is presented. In the current measurement approach, air-coupled excitation and laser interferometric detection are utilized and their effectiveness in characterizing the mechanical properties of a drug tablet by examining its vibrational resonance frequencies is demonstrated. The drug tablet is vibrated via an acoustic field of an air-coupled transducer in a frequency range sufficiently high to excite its several vibrational modes (harmonics). The tablet surface vibrational responses at measurement points are acquired by a laser vibrometer in a non-contact manner. An iterative computational procedure based on the finite element method is developed to extract the mechanical properties of the coated tablet from a subset of its measured resonance frequencies. The mechanical properties measured by this technique are compared to those obtained by a standard contact ultrasonic measurement method and a good agreement is found. Sensitivities of the resonance frequencies to the changes in the tablet mechanical properties are also obtained and discussed. The presented non-destructive technique requires no physical contact with the tablet and operates in the microsecond time-scale. Therefore, it could be employed for rapid monitoring and characterization applications.

Die sonographische Bestimmung des Humerusretrotorsionswinkels

In patients with habitual dislocation of the shoulder and post-fracture malrotation the measurement of humeral torsion is important in preoperative diagnostics. An easy method of ultrasonic measurement of humeral torsion is proposed. The correlation with anthropometric, radiological and CT-measurement is good, what could be shown in 20 macerated humeri. In 111 patients with normal glenohumeral joints the average of humeral retrotorsion was 61 degrees. 86% had a torsion between 40 and 80 degrees.