• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.3
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• pp.279-284
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• 2008

The firmness of fruit is one of the most important quality factors and is highly correlated to the elastic modulus. In this study, the ultrasonic transmission method was applied to evaluate the elastic modulus of the apple. In order to transmit and receive the ultrasonic wave through the whole apple, the ultrasonic measurement setup consisted of ultrasonic pulser, two specially fabricated ultrasonic transducers for fruit and digital storage oscilloscope. Ultrasonic parameters such as ultrasonic wave velocity, apparent attenuation, and peak frequencies were analyzed. The elastic modulus of apple was measured by using compression test apparatus. The correlations between ultrasonic parameters and elastic modulus were analyzed. A multiple linear regression model describing the relationship between elastic modulus and ultrasonic parameters was proposed.

• Journal of Biosystems Engineering
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• v.28 no.3
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• pp.239-244
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• 2003

The potential use of ultrasonic technique for firmness measurement of apples was evaluated. Mechanical properties(bioyield deformation, bioyield strength, rupture deformation, ultimate strength, and elastic modulus) and ultrasonic parameters (ultrasonic velocity, attenuation coefficient and the first peak frequency) of the apple flesh during the storage time were measured and analyzed. Ultrasonic parameters were determined from the measurement of ultrasonic wave transmission through the apple flesh specimen. Mechanical properties were obtained by universal testing machine. The bioyield strength, rupture strength, elastic modulus, ultrasonic velocity, and the first peak frequency of the apple flesh decreased with the storage time. The bioyield deformation, rupture deformation, and ultrasonic attenuation coefficient increased with the storage time. The correlation analysis between ultrasonic parameters and mechanical properties and the storage time was performed. The high correlations were found between the storage time and the ultrasonic parameters, and these relationships seem to be useful for determining the firmness of the apple flesh.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.5
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• pp.239-245
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• 2022

The purpose of this study is to evaluate the degree of microstructural change of materials using ultrasonic nonlinear parameters. For microstructure change, isothermal heat-treated ferritic 2.25Cr steel and low-cycle fatigue-damage copper alloy were prepared. The variation in ultrasonic nonlinearity was analyzed and evaluated through changes in hardness, ductile-brittle transition temperature, electron microscopy, and X-ray diffraction tests. Ultrasonic nonlinearity of 2.25Cr steel increased rapidly during the first 1,000 hours of deterioration and then gradually increased thereafter. The variation in non-linear parameters was shown to be coarsening of carbides and an increase in the volume fraction of stable M6C carbides during heat treatment. Due to the low-cycle fatigue deformation of oxygen-free copper, the dislocation that causes lattice deformation developed in the material, distorting the propagating ultrasonic waves, and causing an increase in the ultrasonic nonlinear parameters.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.3
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• pp.270-279
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• 2003

Parametric studies have been conducted into the variability of the factors affecting the ultrasonic testing applied to weldments. The influence of ultrasonic equipment, transducer parameters, test technique, job parameters, defect type and characteristics on reliability far defect detection and sizing was investigated by experimentation. The investigation was able to build up substantial bank of information on the reliability of manual ultrasonic method for testing weldments. The major findings of the study separate into two parts, one dealing with correlation between ultrasonic techniques, equipment and defect parameters and inspection performance effectiveness and other with human factors. Defect detection abilities are dependent on the training, experience and proficiency of the UT operators, the equipment used, the effectiveness of procedures and techniques.

• Journal of Biosystems Engineering
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• v.37 no.5
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• pp.319-326
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• 2012

Purpose: Cheese texture is an important sensory attribute mainly considered for consumers' acceptance. The feasibility of nondestructive measurements of cheese texture was explored using non-contact ultrasonic sensors. Methods: A novel non-contact air instability compensation ultrasonic technique was used for five varieties of hard cheeses to measure ultrasonic parameters, such as velocity and attenuation coefficient. Five texture properties, such as fracturability, hardness, springiness, cohesiveness, and chewiness were assessed by a texture profile analysis (TPA) and correlated with the ultrasonic parameters. Results: Texture properties of five varieties of hard cheese were estimated using ultrasonic parameters with regression analysis models. The most effective model predicted the fracturability, hardness, springiness, and chewiness, with the determination coefficients of 0.946 (RMSE = 21.82 N), 0.944 (RMSE = 63.46 N), 0.797 (RMSE = 0.06 ratio), and 0.833 (RMSE = 17.49 N), respectively. Conclusions: This study demonstrated that the non-contact air instability compensation ultrasonic sensing technique can be an effective tool for rapid and non-destructive determination of cheese texture.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.232-238
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• 2005

In this study the four classes of the thermally aged 1Cr-1Mo-0.25V specimens were prepared using an artificially accelerated aging method. Ultrasonic tests were performed to get the correlation with fracture toughness. The modified theoretical Vary's equation, considering nonlinear response due to material degradation, was proposed for the correlations between ultrasonic parameters and fracture toughness. Experimental results indicate that ultrasonic attenuation coefficient, velocity and nonlinear parameters produce the correlations with fracture toughness and yield strength.

• Journal of Mechanical Science and Technology
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• v.19 no.2
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• pp.487-495
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• 2005

Mechanical properties of in-service facilities are required to evaluate the integrity of power plants and chemical plants. Non-destructive technique can be used to evaluate the mechanical properties. To investigate the mechanical properties using ultrasonic technique, the four classes of thermally aged specimens were prepared using an artificially accelerated aging method. Ultrasonic tests, tensile tests, fracture toughness tests, and hardness tests were performed for the specimens. Then the mechanical properties were compared with ultrasonic parameters such as attenuation and non-linear parameter. From the investigation, we confirm that the ultrasonic parameter can be used to evaluate the mechanical properties.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1070-1077
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• 2011

This paper is studied on the influence of machining conditions on weldability obtained by ultrasonic machining. The weldability estimation of dissimilar Ni-Cu sheets with the optimization of one-wavelength horn is confirmed by the use of ultrasonic machining. The optimal welding condition with tensile test by setting the ultrasonic machining parameters is suggested and the weldability is estimated by SEM observation and EDX-ray analysis. Experimental studies are worked with the measure of tensile strength and the analysis of SEM photograph after the ultrasonic machining of workpiece. Machining parameters of machining time, pressure, and amplitude are also applied to this paper.

• The Journal of the Acoustical Society of Korea
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• v.15 no.1
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• pp.10-16
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• 1996

Ultrasonic motor is a motor driven by the stator via frictional contact forces generated from ultrasonic vibration of piezoelectric elements. In order to control the ultrasonic motor, it is essential to measure accurately the motor characteristics with respect to driving parameters such as frequency, voltage, phase difference and duty ratio of the driving signals. In this paper, a PC-interfaced evaluation device is developed, and the characteristic curves of the fabricated ultrasonic motor are measured with those parameters. All driving parameters are processed digitally. The developed evaluation device can facilitate charateristics measurements effectively, and provide a base for digital control of the ultrasonic motor.

• Geomechanics and Engineering
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• v.13 no.3
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• pp.371-384
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• 2017

Physical and mechanical properties of rocks are of interest in many fields, including materials science, petrophysics, geophysics and geotechnical engineering. Uniaxial compressive strength UCS is one of the key mechanical properties, while density and porosity are important physical parameters for the characterization of rocks. The economic interest of carbonate rocks is very important in chemical or biological procedures and in the field of construction. Carbonate rocks exploitation depends on their quality and their physical, chemical and geotechnical characteristics. A fast, economic and reliable technique would be an evolutionary advance in the exploration of carbonate rocks. This paper discusses the ability of ultrasonic wave velocity to evaluate some mechanical and physical parameters within carbonate rocks (collected from different regions within Tunisia). The ultrasonic technique was used to establish empirical correlations allowing the estimation of UCS values, the density and the porosity of carbonate rocks. The results illustrated the behavior of ultrasonic pulse velocity as a function of the applied stress. The main output of the work is the confirmation that ultrasonic velocity can be effectively used as a simple and economical non-destructive method for a preliminary prediction of mechanical behavior and physical properties of rocks.