نتایج جستجو برای: ultrasonic parameters
تعداد نتایج: 604637 فیلتر نتایج به سال:
The patterns of ultrasonic backscattered echoes represent valuable information pertaining to the geometric shape, size, and orientation of the reflectors as well as the microstructure of the propagation path. Accurate estimation of the ultrasonic echo pattern is essential in determining the object or propagation path properties. This paper proposes a parameter estimation method for ultrasonic e...
Practical aspects of design and application radio frequency (RF) transformers in an ultrasonic system excitation channel are analysed. Design steps are discussed for those willing to design their own transformer an for excitation channel. Investigation has been carried out on what generator parameters can be obtained if instead of a purely active output stage the impedance matching RF transform...
Currently available non-invasive clinical methods for diagnosing osteoporosis are mainly associated with ionizing radiation. Ultrasonic assessment of bone disease is a more recent technology. A theoretical explanation for the relationship between ultrasonic parameters and bone structure is necessary. Thus, two types of bone samples of perspex (HAP) and perspex-glass beads were produced. Ea...
ultrasonic machining (usm) is a mechanical material removal process used to erode holes and cavities in hard or brittle work pieces by using shaped tools, high-frequency and an abrasive slurry. this paper addresses the concept and development of an expert system (es) for hard and brittle material, such as glass, quartz, diamond, carbides, semi conducting materials, ceramic and graphite which ca...
The subsurface defect in the wheel tread caused from Rolling Stock Fatigue (RCF) has become more danger in high speed railway. The conventional UT and phased array UT have deficiency to find the subsurface defect from the tread surface because of limitation of ultrasonic near field. In this paper, the subsurface defect is studied by simulation and experimental results with ultrasonic technique....
In the present paper, we have synthesized the NiO nanoparticles with chemical route. Further, the uniform suspensions of NiO nanoparticles in ethylene glycol of different concentrations have been prepared. Samples were characterized with Acoustical Particle Sizer (APS-100) for the frequency dependent ultrasonic attenuation in the respective samples; subsequently the particle size determination ...
Ultrasonic scanning experiments were conducted for detecting defects in wood pallet parts using rolling transducers. The characterization of defects is important for sorting and grading pallet parts, as well as for manufacturing quality and durable pallets. This paper reports the scanning results for stringers and deckboards – the two main components of pallet for red oak and yellow-poplar spec...
One of the great challenges in the processing of materials using Equal Channel Angular Pressing (ECAP) is the high forming forces required to produce large shear deformation in the material. Researchers show that the friction forces between the die and the sample constitute a great part of the total forming forces. Recently, ultrasonic vibrations are successfully implemented into the ECAP proce...
One of the new clinical techniques to assess the lower body parameters is the wearable ultrasonic sensors. The device which can measure the static and dynamic balance abilities in sport and clinical setting by the traveled signals of ultrasonic transmitter and receiver between two feet was developed and validated. The new device consisted of a pressure gauge and a digital centimeter indicator a...
The ultrasonic attenuation is evaluated at 300 K along [100], [110], and [111] directions for the characterization of bcc metal Ta. The size of the metal is considered in nanorange. Ultrasonic velocity, Grüneisen parameter and acoustic coupling constant that depend on second and third order elastic constants are calculated for determination of ultrasonic attenuation coefficient. Second and thir...
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