Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2018 ( 5 )

2017 ( 7 )

2016 ( 3 )

2015 ( 11 )

Custom range...

Search Results: 1 - 10 of 408 matches for " Riichi Murayama "
All listed articles are free for downloading (OA Articles)
Page 1 /408
Display every page Item
Non-Contact Stress Measurement during Tensile Testing Using an Emat for SH0-Plate Wave and Lamb Wave  [PDF]
Riichi Murayama
Journal of Sensor Technology (JST) , 2011, DOI: 10.4236/jst.2011.13009
Abstract: The stress on a test specimen during tensile testing is generally measured by a strain gauge. This method has some problems in that it would influence the measurement conditions of the tensile test and can evaluate only the position at which the strain gauge is attached. The acoustoelastic method is proposed as a method replacing the strain gauge method. However, an ultrasonic sensor with a piezoelectric oscillator requires a coupling medium to inject an ultrasonic wave into a solid material. This condition, due to the error factor of the stress measurement, makes it difficult for the ultrasonic sensor to move on the specimen. We then tried to develop a non-contact stress measurement system during tensile testing using an electromagnetic acoustic transducer (EMAT) with an SH0-plate wave and S0-Lamb wave. The EMAT can measure the propagation time in which the ultrasonic wave travels between a receiver and a transmitter without a coupling medium during the tensile testing and can move easily. The interval between the transmitter and the receiver is 10mm and can be moved along the parallel direction or the vertical direction of the tensile load. The transit time was measured by a cross-correlation method and converted into the stress on the test specimen using the acoustoelastic method. We confirmed that the stress measurement using an SH0-plate wave was superior to that with an S0-Lamb wave.
A New Guide Wave Inspection System Using Three Polarized Transverse Wave EMATs without Any Couplant  [PDF]
Riichi Murayama
Journal of Sensor Technology (JST) , 2016, DOI: 10.4236/jst.2016.64009
Abstract: A guide wave is provided with the characteristic of long range propagation in the axis direction of a pipe, so it is possible to detect many defects over a large pipe area at once. At present, there is a technique to generate a guide wave using a piezoelectric element (PZT). However, the transverse wave-transducer using PZT needs to require a high viscosity couplant because the transverse wave cannot travel into typical liquid like water or oil. A guide wave inspection system that uses an electromagnetic ultrasonic transducer (EMAT) which does not require any couplant has then been developed to solve this trouble. First, a guide wave into a pipe, L, T and F-mode, can be transmitted and received by a polarized shear horizontal transverse wave propagating to the thickness direction when the vibration direction has been adjusted to the best direction. At next stage, the three EMATs for L, T and F-mode with different polarized vibration directions were piled up to improve the performance at the same position under the permanent magnet to inspect the pipe at the same condition. Next, the system with the EMATs can be confirmed to be able to detect three guide wave modes signal with enough intensity. Finally, the detection performance using the test pipes with any artificial defects has been done by the developed pipe inspection system, and any drilled holes and any notches can be detected. It is indicated that the developed system could be useful in real industrial field.
Analysis of Land Subsidence Using the HES  [PDF]
Witsarut Sriratana, Riichi Murayama
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2012, DOI: 10.4236/jemaa.2012.47043
Abstract: This study presents a methodology for analysis of the industrial machine alignment in the production line. The level of land subsidence in the area of the industrial machine location was assessed by adopting Hall Effect Sensor (HES). A computer was used for real-time data collecting and displaying the angle of subsidence over operational period. The measurement module consists of two flat-curve permanent magnets mounted parallelly and the magnetic poles which were placed in position that can be generating the magnetic tension force. The center between two permanent magnets was the sensor namely HES placed perpendicularly to the magnetic fluxes. The permanent magnets were the moving parts which can be displaced depending on the inclined angle of land subsidence. Analysis of the relationship between the incline angle of the measurement module and the output voltage from the HES was considered from the function of subsidence angle and magnetic density on X-axis and perpendicular angle (Y-axis) with the resolution of 100 mV per degree. There were two ranges of measurement according to the angle resolution, –20 to 20 degree at 1 degree of resolution per step and –6 to 6 degree at 0.01 degree of resolution per step.
Elimination of Oil Residual inside the Copper Pipe Using Ladder Technique  [PDF]
Witsarut Sriratana, Riichi Murayama
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.51002

This study presents the methodology to eliminate oil residual in copper pipe due to rolling process for manufacturing coil used in air conditioner. The pressure caused by Nitrogen flow rate was applied starting from 0, 5, 10, and 15 bar, respectively which was depending on time delay and pipe length. The developed system was divided into 2 modules: Parallel pressure ladder module (PPLM) [1] and Serial pressure ladder module (SPLM) which were experimented with 2 sizes of copper pipe: diameter 7.29 mm, thickness 0.25 mm, and length 10 km, and diameter 8 mm, thickness 0.25 mm, and length 10 km. From experiment, it can be noted that PPLM would perform better in elimination of oil residual compared to SPLM. About 97.44% (0.04 mg/m) and 97.59% (0.05 mg/m) of oil residual can be respectively eliminated from diameter 7.29 mm pipe and diameter 8 mm pipe which exceeded the standard allowance of 30% or 0.1 mg/m. Moreover, the cost of Nitrogen can be reduced by 6.25% per month.

Measurement of the Lubricant Properties Using Hall Effect Sensor: A Study on Contamination and Viscosity  [PDF]
Witsarut Sriratana, Riichi Murayama
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.54051

This study proposes the development of contamination measurement for industrial machines based on magnetic field method. A permanent magnet was used to generate the 0.17 T magnetic fields and Hall Effect sensor was applied to measure the contamination level of metal particles in industrial machine lubricant during operation time and to predict the replacement period if the lubricant condition does not meet the standard (NAS 1638). Contamination level of metal particles was directly related to the output voltage of Hall Effect sensor. When there was any movement of metal particles to the permanent magnet, the measured result was then transferred to a computer for analysis. This methodology could be applied to experiment the conditions of used lubricant for assessing the contamination and the metal particle remaining in the tank or inside the pipe of the machine as well as the conditions of car lubricant and other lubricants used in industrial processes.

Study of an Omnidirectional Guide Wave Sensor Using an EMAT  [PDF]
Riichi Murayama, Kazuki Iwaya
Journal of Sensor Technology (JST) , 2017, DOI: 10.4236/jst.2017.72002
Abstract: Nondestructive inspection of structures is important for ensuring the safety of the social infrastructure. Among them, the ultrasonic inspection method plays a role as a major technology. However, when examining a huge structure, the inspection time tends to be very long. Therefore, a system for transmitting and receiving ultrasonic waves in all directions from the ultrasonic sensor has been constructed. Several types of ultrasonic sensors using this concept have already been devised, but since the ultrasonic energy is dispersed in all directions, there is a problem that a sufficient detection performance cannot be ensured, especially when the thickness of the material to be inspected becomes thick. Therefore, we developed a highly sensitive omnidirectional ultrasonic sensor utilizing the resonance phenomenon of the ultrasonic wave propa-gating in the thickness direction. The omnidirectional ultrasonic system also consists of an electromagnetic ultrasonic transducer (EMAT) using a circular magnet. It is possible to inspect the plate thickness from 0.3 mm to 10 mm and the inspection range of the diameter of 300 mm around the sensor by the developed system. It is indicated that the developed system allows the high-speed inspection of huge structures.
A Pipe Inspection Using a Circumferential SH-Mode Plate Wave Generated in a Pipe by an Electromagnetic Acoustic Transducer (EMAT)  [PDF]
Riichi Murayama, Hideo Nishino
World Journal of Engineering and Technology (WJET) , 2018, DOI: 10.4236/wjet.2018.63043
Abstract: Inspection of a pipeline is essential for the safe use of such facilities. A trial sensor using an electromagnetic acoustic transducer (EMAT), which can generate the SH-mode plate wave propagating in the circumferential direction, has been developed to realize this objective. It consists of a circulating electromagnetic induction coil around the pipe and many permanent magnets arranged on the surface of the pipe in the circumferential direction. It is postulated that the intensity of the SH-mode plate wave propagating in the circumferential direction is dependent on any defects in the circumferential direction. A resonance method was then utilized to obtain a stronger received signal. As a result, it was confirmed that the resonance status can be detected. The relationship between the signal intensity and the pipe thickness was then evaluated. It was confirmed that the wall thickness of about 20% can be detected under a static condition. Finally, a moving test has been executed by using an axially traveling device manufactured by trial. The test pipes with different sizes of drilled holes were prepared. The change in the received signal intensity according to different sizes of the drilled holes was successfully detected.
Application of the HES in Angular Analysis  [PDF]
Witsarut Sriratana, Riichi Murayama, Lerdlekha Tanachaikhan
Journal of Sensor Technology (JST) , 2012, DOI: 10.4236/jst.2012.22013
Abstract: This study presents an analysis of the relationship of angles and trigonometric functions by applying Hall Effect Sensor (HES). Electromagnetic density of 4.624 mT can be generated from the Helmholtz coil. Angle of shaft which was installed at the center of the Helmholtz coil perpendicularly to horizontal plane was considered as reference and can be rotated. In this study, an experiment for measuring the angle of shaft declination on X-axis was carried on. Ranges of measurement were related to the angle resolution between –15 to 15 degree with 1 step degree interval from perpendicular angle (Y-axis). Analysis of the relationship between shaft declination and electromagnetic field was performed using HES device which was installed on the top of shaft and perpendicularly to reference electromagnetic field [1,2]. The angle declining from the origin which was normal to magnetic field can be determined by measuring the relationship between Hall voltage and magnetic field. Normally, electromagnetic field is nonuniform and varied by point in Helmholtz coil radius. Shaft angles on X-axis were measured for assessing the repeatability of system developed. Five values of results were measured repeatedly at the same input. It can be observed that the system developed can provide the results with the best accuracy and reliability of 95%.
Synthesis and Analysis of PZT Using Impedance Method of Reactance Estimation  [PDF]
Witsarut Sriratana, Riichi Murayama, Lerdlekha Tanachaikhan
Advances in Materials Physics and Chemistry (AMPC) , 2013, DOI: 10.4236/ampc.2013.31010
Abstract: This study presents an analysis of equivalent circuit namely Butterworth Van Dyke (BVD) [1,2] by using impedance method to stimulate Zirconate Titanate (Piezoelectric ceramic) which is initially synthesized from Lead Oxide (PbO), Zirconium Dioxide (ZrO2) and Titanium Dioxide (TiO2) and vibrated in thickness mode. The reactance was estimated in the frequency range lower than the resonance frequency and then compared to the impedance obtained from measurement using impedance analysis machine model HP4192A and HP4194 [3]. The results from HP4194 were analyzed for BVD parameters: Motional resistance (R1), Inductor (L1), Capacitor (C1), and Capacitor corresponds to the electrostatic capacitance (Co). Another accuracy analysis was compared by the calculation results using the method of IEEE 176-1987 [4] to the
Study of Material Evaluation Probe Using a Longitudinal Wave and a Transverse Wave  [PDF]
Riichi Murayama, Makiko Kobayashi, Cheng-Kuei Jen
Journal of Sensor Technology (JST) , 2013, DOI: 10.4236/jst.2013.32005
Abstract: Transmitting a longitudinal wave and a traverse wave into a composite material in a molten state has been studied in the online control of the composite material which cannot be evaluated by a conventional ultrasonic sensor as a final analysis, using the difference in the propagation characteristics of both modes. It is especially expected that measurement of the physical quantity which was not able to be conventionally measured can be performed by carrying out coincidence measurement of the ultrasonic wave in both modes. Therefore, in this research study, an ultrasonic probe, which can simultaneously transmit and receive a longitudinal wave and a traverse wave has been developed using an electromagnetic acoustic transducer (EMAT) because it has the advantage of measuring high temperature samples. In this study, two methods have been compared. The 1st method uses a traverse wave EMAT that travels in a vertical direction and a bar wave by which the low order mode is equivalent to longitudinal wave vibration. The other method is to carry out the mode conversion of the traverse wave by a traverse wave-EMAT. The longitudinal converted from the transverse wave are spread in the axis direction. As the experimental results of both optimizations of the drive conditions, it has been confirmed that the 2nd mode conversion method was promising. This paper reports about the trial process and the experimental results.
Page 1 /408
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.