• Transactions of Materials Processing
• /
• v.19 no.6
• /
• pp.363-371
• /
• 2010

In ultrasonic vibration drawing, the drawing forces can be reduced by applying ultrasonically oscillating dies. Ultrasonic vibration drawing has been considered as a means of accommodating high-level drawing processes such as shaped wire, ultrafine wire, and the wire drawing operation in semidry or dry condition. Prior studies were attempted to analyze the mechanism of improved drawing performances, such as reduced drawing force and improved lubrication characteristic. However, researches on design rule for ultrasonic vibration drawing system are not yet carried out. The principal objectives of this work are to design a set of tooling capable to superimpose the oscillations and to observe by experiments the influence of the ultrasonic oscillations on the wire drawing.

• Journal of the korean Society of Automotive Engineers
• /
• v.15 no.3
• /
• pp.47-54
• /
• 1993

This paper describes briefly the effect of ultrasonic fuel supply device on the performance of four stroke cycle gasoline engine. Experiments were carried out to clarify the effect of ultrasonic fuel supply device on the engine output, traveling fuel consumption ratio, exhaust emissions. The results were obtained as follows: 1.Engine output was increased 9-14% in comparison with that of the conventional injector. 2.Travelling fuel consumption ratio was improved 17-29% in comparison with that of the conventional injector. 3. CO, HC exhaust emissions was decreased compared to the value of the conventional injector. 4.Fuel consumption ratio in highway driving test was improved about 10% in comparison with that of the conventional injector.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.76-81
• /
• 2001

Ultrasonic flowmeters have more advantages than the conventional method using pressure-difference. In these reasons, many advanced nations are already selling the commercial model. In RIST, we have been developed ultrasonic gas flow meter for the localization since a project was been contracted with POSCO in 1997. This paper describes a new ultrasonic gas flowmeter. This ultrasonic gas flowmeter is developed for accurate measurement of gases in a harsh environmental conditions. It is especially suited for measuring LDG, COG, BFG gases produced in iron & steel making process. In this study, we had developed the commercial model about the first tested model and applied a completed system to the POSCO gas line. Its performance has already well been proven by extensive field tests for several months in POSCO, iron & steel making company.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.10 no.6
• /
• pp.95-101
• /
• 2001

This work is concerned with construction of the intelligence stress predictor far compression strength evaluation using neural network-ultrasonic waves. The contact pressure in jointed plates was measured by using ultrasonic technique. Neural network is used to evaluate and predict contact pressure from the results of the calibration curves. The organized neural system was leaned with the accuracy of 99%, as a result of learning the ultrasonic echo ratio to the contact pressure measurement between SM45C and STS410 materials. And it could be evaluated and predicted with the accuracy of 90% in the evaluation of ultrasonic echo ratio difference in the same surface roughness and contact pressure, and 85% in the prediction of virtual ultrasonic echo ratio. Thus the proposed stress predictor is very useful for the evaluation and prediction of the contact pressure between SM45C and STS410 materials.

• Tribology and Lubricants
• /
• v.16 no.5
• /
• pp.351-356
• /
• 2000

The feasibility of an ultrasonic technique using a pulse-echo method of normal-incident compressional waves was evaluated for its sensitivity to the worn surface and near surface damage due to wear. Worn surfaces were generated at various oscillation frequency under a given load and amplitude and these surface were in situ monitored using a ultrasonic wave detection system. Analysis of the ultrasonic waves received from the worn surface revealed a close relationship between the surface and near-surface damage and the maximum echo-amplitude of the compressional waves. The ultrasonic technique was successful in assessing the level of severity of the worn surface in real time during the wear process. It is also shown that the wear depth can be easily measured by the calculation of change of the specimen thickness based on the wave speed measured for the specimen medium.

• Transactions of Materials Processing
• /
• v.25 no.6
• /
• pp.373-378
• /
• 2016

Recent researches have reported that the superposition of ultrasonic vibrations in metal forming provides beneficial effects such as the reduction of forming load, flow stress and interfacial friction which improves the surface quality of end products. This paper presents experimental investigations on the effects of ultrasonic vibrations in upsetting tests of aluminum. The ultrasonic exciting system consists of piezoelectric transducer and resonator was designed and constructed to superimpose high frequency oscillation on the forming tools. Ultrasonic vibration-assisted upsetting tests were performed for three vibration modes five amplitudes, and the results were compared with those of conventional upsetting tests. The results showed that the superimposition of ultrasonic vibration reduces the upsetting load, and the load reduction is only dependent on the amplitude of the applied vibration regardless of deformation histories and vibration modes.

• Journal of Advanced Navigation Technology
• /
• v.20 no.4
• /
• pp.298-304
• /
• 2016

In this paper, a wavelet packet transform method is proposed for improving the altitude control performance of quadrotor UAV using an ultrasonic rangefinder. A ground tests are conducted using an ultrasonic rangefinder that is much used for vertical takeoff and landing. An ultrasonic rangefinder suffers from signal's spike due to specular reflectance and acoustic noise. The occurred spikes in short time span need to be analyzed at both sides time and frequency domain. The analyzed spikes of the ultrasonic rangefinder using a wavelet packet transform. Compared with the discrete wavelet transform, the wavelet packet decomposition can obtain more abundant time-frequency localization information, so it is more suitable for analyzing and processing ultrasonic signals spike. Experimental results show that it can effectively remove the spikes of the ultrasonic rangefinder.

• Journal of Energy Engineering
• /
• v.7 no.1
• /
• pp.17-23
• /
• 1998

A simplified experiment was performed to figure out the atomization characteristics of highly viscous liquid of rice-bran oil by applying ultrasonic energy to improve the atomization of spray droplets. A spray system, an ultrasonic system, and three kinds of pintle-type nozzles(pin-edge angle: 5 , 10 , 15 ) were manufactured. To investigate the effects of ultrasonic energy on the atomization of a highly viscous liquid, a phase doppler particle analyzer was used for the measurement and calculation of spray droplets data. Nozzle opening pressures were chosen of 3 levels, i.e, 10, 13, 16 MPa. As a result, it could be concluded that the ultrasonic energy was effective to improve the spray atomization when applied to the fuel by means of 3 different nozzles because of the effects of the liquid fuel cavitation and relaxation between molecules caused by ultrasonic energy. The improvement rate of the spray atomization by the ultrasonic spray atomization by the ultrasonic spray compared with the conventional spray was about 10% increase in the case of pintle type nozzles. With the increase of pin-edge angles the distribution lines by nozzle opening pressures are declined for both conventional and ultrasonic sprays. This means that the increase of the pin-edge angle improves the atomization of sprays.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.11
• /
• pp.1256-1263
• /
• 2012

The present study covers the ultrasonic patterning process to replicate micro-patterns on a polymer substrate. The ultrasonic patterning process uses ultrasonic waves to generate frictional heat between an ultrasonic horn and the polymer substrate, from which the surface region of the polymer substrate is softened sufficiently for the replication of micro-patterns. The ultrasonic patterning process can divided into two categories according to the direction of vibration transmission: direct patterning and indirect patterning. The direct patterning uses a patterned horn, and the ultrasonic vibration is transferred directly from the patterned horn to the substrate. On the contrary, the indirect patterning process uses a plain horn, and the micro-patterns are engraved on a mold that is located below the substrate. Thus, the micro-patterns are replicated as an indirect manner. In this study, these direct and indirect patterning processes are compared in terms of the replication characteristics. Additionally, the possibility of double-side patterning is also discussed in comparison with the conventional single-side patterning process.

• Journal of Fisheries and Marine Sciences Education
• /
• v.19 no.3
• /
• pp.478-490
• /
• 2007

A technology of ultrasonic biotelemetry for tracking fish behavior is investigated. The ultrasonic biotelemetry system is constituted by a transmitter and a receiving system. Because a pinger was mainly used for the transmitter, the capability for pinger to possess was investigated and the efficient usage for pinger was examined. A source pressure level and a frequency were synthetically examined so that pinger could realize small size, a light weight, and a long life time. The receiving system is divided roughly into directional hydrophone systems and acoustic positioning systems by the receiving method. The directional hydrophone system is divided into single beam and multiple beam with the number of hydrophone, and the acoustic positioning systems is divided into LBL (Long Base Line), SBL (Short Base Line), and SSBL (Super Short Base Line) on the basis of base line. The present situation, the merits and demerits, and the principle of each receiving method were investigated in detail, and the efficient usage for each receiving method were examined.