• 한국물환경학회지
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• 제25권5호
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• pp.667-673
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• 2009

This study has carried out to evaluate the performance of single (electrolysis, UV and ultrasonic process) and complex process (Electrolysis+UV, UV+Ultrasonic and Electrolysis+Ultrasonic) for the purpose of disinfection of Escherichia coli in water. The order of disinfection performance for E. coli in single process lie in: Electrolysis ${\fallingdotseq}$ UV >> ultrasonic process. OH radical was not produced in single disinfection process. Among the three kinds of complex process, disinfection performance of the Electrolysis+UV was higher than that of the other process (UV+Ultrasonic and Electrolysis+Ultrasonic). It demonstrated a synergetic effect between the UV and electrolysis. When the use of $Na_2SO_4$ as electrolyte instead of NaCl, current increase or more reaction time was needed for the complete disinfection. The disinfection performance of pre-electrolysis (20 W, 30sec) and post-UV (10 W, 30 sec) was higher than that of the simultaneous electrolysis+UV process at same electric power (30 W, 30 second).

• Korea-Australia Rheology Journal
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• 제20권2호
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• pp.79-88
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• 2008

In this study, we focus on the improvement of the filling efficiency in injection molding by application of ultrasonic vibration. While studies about the filling efficiency of typical filling processes in the injection molding have been widely performed, there have been only few studies about the filling efficiency of an ultrasonic process. The effect of the ultrasonic vibration is an important process condition, which influences the flow characteristics of polymer melt. This new condition even affects well-known injection conditions such as cavity pressure, injection temperature and mold temperature. For this study, we carried out a numerical analysis by appropriate modeling and analysis of the ultrasonic process in the filling process. To verify this numerical analysis, we compared the numerical results with the experimental data. Also, we analyzed the filling process in a thin cavity using this numerical analysis. To understand the flow characteristics of polymer melt in the ultrasonic process, we substituted real and complex vibration conditions with simplified and classified conditions according to the position of vibrating cavity surfaces and the phase difference between two opposing cavity surfaces. We also introduced MFR (melt flow ratio) as a new index to estimate the filling efficiency in the ultrasonic process.

• KSBB Journal
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• 제25권1호
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• pp.33-40
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• 2010

Conventional disinfectants and disinfection method are expensive, hazardous and often require long periods of exposure. Recently, there is growing interest in complex disinfection process as a disinfection technique in medical instruments such as endoscope, hand piece bur to improve the disinfection efficiency and conveniency. The aim of this study was to evaluate the performance of a new complex process for the purpose of disinfection of Escherichia coli in water. Three single process (electrolysis, UV and ultrasonic process) was combined dual and triple disinfection process. The order of disinfection performance for E. coli in dual process lie in: Electrolysis + UV > Electrolysis + Ultrasonic > UV + Ultrasonic process. Disinfection efficiency of E. coli and degradation of N, N-Dimethyl-4-nitrosoaniline (RNO, indicating material of OH radical formation) of dual process was higher than that of the triple process (Electrolysis + UV + Ultrasonic process). In electrolysis + UV process, disinfection tendency was well agreed with RNO degradation tendency.

• 소성∙가공
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• 제11권7호
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• pp.596-600
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• 2002

The ultrasonic bonding method and its feasibility are investigated in this work for joining the micro components and MEMS packaging. The ultrasonic bonding process is analyzed using a lumped mode, and preliminary experiments using the eutectic solder and copper pin were carried out to verify possibility to MEMS packaging. The ultrasonic bonding process appears to be adequate for MEMS packaging by providing localized heating at the selected area. Microscopic behavior of the bond joint through ultrasonic vibration needs further investigation.

• 소성∙가공
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• 제21권2호
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• pp.119-125
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• 2012

The present study addresses a direct patterning process on a plastic film using ultrasonic vibration energy. In this process, a tool horn containing micro-patterns is attached to an ultrasonic power supply, and is used with ultrasonic vibration to replicate micro-patterns on the surface of a plastic film. To improve the replication characteristics of the micro-patterns, the effect of the die shape of the ultrasonic patterning process was investigated with respect to the flow direction control. Finite element analyses were performed to predict the flow characteristics of the polymer with variations in die design parameters. Experiments were conducted using the optimally-designed die, from which it was possible to attain much improved pattern replication.

• Journal of Welding and Joining
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• 제21권5호
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• pp.534-539
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• 2003

An efficient soldering process using the longitudinal ultrasonic vibration is introduced in this work for electronic packaging. The effects of the process parameters such as the ultrasonic frequency, amplitude, dimension of the metal bump and solder are analyzed through a viscoelastic lumped model. The viscoelastic properties of the eutectic solder were measured for calculation and evaluation of heat generation capability of the solder. Experiments were conducted to verify the possibility of the proposed ultrasonic soldering method by inserting the Cu and Au bumps into the solder block. Localized heating due to ultrasonic vibration melts the solder near the metal bump, which demonstrates the applicability of the ultrasonic soldering method to the high-density electronic packaging.

• 한국공작기계학회논문집
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• 제13권2호
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• pp.104-111
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• 2004

Ultrasonic machining is a non-thermal, non-chemical, md non-electorial material removal process, and thus results in minimum modifications in mechanical properties of the brittle material during the process. Also, ultrasonic machining is a non-contact process that utilize ultrasonic vibration to impact a brittle material. In this research characteristics of micro-hole machining for brittle materials by ultrasonic machining(USM) process have been investigated. And the effect of ultrasonic vibration on the machining conditions is analyzed when machining fir non-conductive brittle materials using tungsten carbide tools with a view to improve form and machining accuracy.

• Journal of Welding and Joining
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• 제22권1호
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• pp.65-70
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• 2004

A soldering process with longitudinal ultrasonic is conducted in this work using the Au bump and substrate. Localized heating of the solder is achieved and the stirring action due to the ultrasonic is found to influence the bond strength and microstructure of the eutectic solder The acceptable bonding condition is determined from the tensile strength. Since the multiple bonds can be formed simultaneously with localized heating, the proposed ultrasonic soldering method appears to be applicable to the high-density electronic package.

• 한국기계가공학회지
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• 제13권3호
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• pp.96-102
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• 2014

This study focused on the effects of ultrasonic vibration on a machined surface of Al6061 material in the endmill cutting process. It is known that ultrasonic vibration greatly increases the efficiency of the machining process when cutting or grinding. An ultrasonic vibration table was developed for application to ultrasonic vibration endmill machining experiments.Inthisstudy,the surface roughness and actual depth of the cut measured confirm the effects of ultrasonic vibration. As a result of the experiments, the actual depth of the cut increased during endmill machining when using ultrasonic vibration. The surface roughness was improved with increases in the amplitude of the vibration and the depth of the cut.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1882-1891
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• 2001

The present paper investigated the effect of ultrasonic vibrations on the melting process of a phase-change material (PCM). Furthermore, the present study considered constant heat flux boundary conditions unlike many of the previous researches adopted constant wall temperature conditions. Therefore, in the present study, modified dimensionless parameters such as Ste* and Ra* were used. Also, general relationships between melting with ultrasonic vibrations and melting without ultrasonic vibrations were established during the melting of PCM. Experimental observations show that the effect of ultrasonic vibrations on heat transfer is very important throughout the melting process. The results of the present study reveal that ultrasonic vibrations accompany the effects like agitation, acoustic streaming, cavitation, and oscillating fluid motion. Such effects are a prime mechanism in the overall melting process when ultrasonic vibrations are applied. They enhance the melting process as much as 2.5 tildes, compared with the result of natural melting. Also, energy can be saved by applying ultrasonic vibrations to the natural melting. In addition, various time-wise dimensionless numbers provide conclusive evidence of the important role of ultrasonic vibrations on the melting phenomena.