• 한국생산제조학회지
• /
• 제26권2호
• /
• pp.158-165
• /
• 2017

This study investigated spraying factors applicable to stripper usage. Cyclodextrine, as environment-friendly material, was included in the stripper composition. An efficient spray technology was applied for the Photoresist strip. For industrial applications, stripping requires a temperature below $50^{\circ}C$, a strip time within 50 s, and chemically stable activation. Spraying factors were organized considering many conditions-orifice diameter, working pressure (inlet speed), spray distance, and spray angle. For commercial practicability, the flow rate was limited to 3 L/min. The nozzle parameters were nozzle orifice diameter of 1.8-2.2 mm, spray distance of 40-60 mm, and injection speed of 0.7-1.2 m/s. Through the thermal spray movement of the fluid, the thermal boundary layer for a chemical reaction just above the ITO-glass surface and momentum region for sufficient agitation (above 4 m/s) was achieved.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.508-511
• /
• 2004

This study focused on the effect of autonomic microcapsules on the mechanical properties of structural material. Several types of microcapsules with healing agents were manufactured by varying agitation speed of high speed stirrer. The size distribution of microcapsules was measured by a particle size analzer. The epoxy specimens embedded with microcapsules were manufactured and the degree of cure of such epoxy specimen was measured by a differential scanning calorimetry. The tensile modulus and tensile strength in epoxy specimens embedded with microcapsules were evaluated in order to investigate the effects of microcapsules on mechanical properties of structural materials. The configuration of microcapsules and morphology of fracture surfaces for the epoxy specimen were examined by an optical microcope and a scanning electron microscope. According to the results, tensile strength of the epoxy specimen embedded with microcapsules was indicated a little reduction, but tensile modulus was not much affected on microcapsules.

• Journal of Mechanical Science and Technology
• /
• 제17권8호
• /
• pp.1203-1210
• /
• 2003

Emission of ultrasonic vibration to turbulent flow promotes the turbulence generation due to the resonantly oscillating pressure field and thereby induced cavitation. In addition, ultrasonic vibration is well transmitted through water and not dissipated easily so that the micro-bubbles involved in the fluid induce the gaseous cavitation if the bubbles are resonated with the ultrasonic field. In the present study, we found through LDV measurement that the gaseous cavitation induced by ultrasonic vibration to CO$_2$saturated water flow in the rectangular cross-sectioned straight duct enhances turbulence much more than the case of non-ultrasonic or normal ultrasonic conditions without gaseous cavitation. We also found that the fluctuating velocity component induced by emitting the ultrasonic vibration in normal direction of a rectangular channel flow can be redistributed to stream-wise component by the agitation of gaseous cavitation.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2000년도 추계 학술대회논문집
• /
• pp.109-114
• /
• 2000

Mechanical agitation is widely used in industrial process engineering. In the present study, peformed was a numerical simulation on flows in a $45^{\circ}$ Pitched Paddle Type mixer. Through a CFD technique, effects of the position of the impeller on resultant flow pattern was studied. Results of computed torque on impeller to maintain the flow are also compared to the experimental data, and showed good qualitative agreements.

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

• Journal of Mechanical Science and Technology
• /
• 제19권10호
• /
• pp.1902-1909
• /
• 2005

A process for production of ethyl ester for use as biodiesel has been studied. The sodium hydroxide catalyzed transesterification of soybean oil with ethanol was carried out at different molar ratio of alcohol to oil, reaction temperature and catalyst amount for a constant agitation in two hours of reaction time. Central composite design and response surface methodology were used to determine optimum condition for producing biodiesel. It was found that ethanol to oil ratio and catalyst concentration have a positive influence on ester conversion as well as interaction effects between the three factors considered. An empirical model obtained was able to predict conversion as a function of ethanol to oil molar ratio, reaction temperature and catalyst concentration adequately. Optimum condition for soybean ethyl ester production was found to be moderate ethanol to oil ratio (10.5: 1), mild temperature range ($70^{\circ}C$) and high catalyst concentrations ($1.0\%$wt), with corresponding ester conversion of $93.0\%$.

• Parasites, Hosts and Diseases
• /
• 제52권3호
• /
• pp.317-319
• /
• 2014

The oocyst wall is severed by means of mechanical injury or chemical agents. This study reports the percentage of in vitro sporocyst release following mechanical shaking in the presence of varying sizes of glass beads. Glass beads measured 0.5, 1, and 3 mm in diameter and were shaken with the oocysts for different times ranging from 5 sec to 5 min. Approximately 80% of sporocysts were released with 5 min of shaking in the presence of 3 mm glass beads, as well as 30 sec with 0.5 mm beads and 1 mm glass beads. The release of sporocysts of E. tenella was most efficient using 1 mm glass beads and treatment times of 30 sec to 1 min. Therefore, the use of 1 mm glass beads with 30 sec to 1 min of agitation is recommended in order to maximize sporocyst release and recovery and to improve the yield of viable sporozoites for use in biochemical, tissue culture, and immunological applications of coccidia.

• 대한기계학회논문집B
• /
• 제32권5호
• /
• pp.327-334
• /
• 2008

Effects of tube inclination on pool boiling heat transfer have been studied for the saturated water at atmospheric pressure. For the analysis, seven inclination angles varying from the horizontal to the vertical and two tube diameters(25.4 and 30.0 mm) are tested. According to the results, inclination angles result in much change on heat transfer. For the same wall superheat(about $5.3^{\circ}C$) the ratio between two heat fluxes for the $45^{\circ}$ inclined and the vertical has the value of more than five when the tube diameter is 25.4mm. As the inclination angle is increasing from the horizontal to the vertical direction heat transfer is gradually increasing because of the increase in liquid agitation. However the detailed tendency depends on the ratio between the tube length and the diameter.

• 대한기계학회논문집B
• /
• 제36권8호
• /
• pp.775-782
• /
• 2012

수직으로 설치된 하부폐쇄 환상공간 내부의 풀비등 열전달 메카니즘을 알기 위하여 환상공간의 튜브 길이를 0.3m와 0.6m 사이에서 변경하였다. 실험을 위해 0.2m의 가열 길이를 갖는 직경 19.1mm인 스테인리스강 튜브와 대기압 상태 하에 있는 물을 사용하였다. 외부 튜브 길이가 열전달에 미치는 영향을 분명하게 살펴보기 위해 환상공간에 대한 결과를 환상공간이 없는 단일튜브에 대한 결과와 서로 비교하였다. 동일 열유속에서 외부튜브 길이의 증가는 틈새간격이 3.5mm인 경우에는 열전달계수의 증가하지만 틈새간격이 15.5mm인 경우에는 열전달계수가 감소하였다. 이러한 경향의 주된 원인은 액체교란의 차이로서 설명된다.

• 한국표면공학회지
• /
• 제24권4호
• /
• pp.179-186
• /
• 1991

The effects of silicone contents and flow rates(agitation rates) of electrolyte on the formation and mechanical properties of hard anodized film of Al-Si alloy have been studied in 12% H2SO4 + 1% Oxalic acid with varying the silicone contents in the rance of 0 to 11.6% and the flow rates of electrolyte in the range of 0 to 90cm/sec. The film forming voltage required to maintain an equivalent current density significantly increase with the silicone content of Al-Si alloys due to a low conductivity of silicone. Hardness and wear resistance of the anodized film of Al-Si alloys decreases wit increasing the silicone content. The increase in the flow rate of electrolyte has a similar influence on the formation and mechanical properties of anodized film as does the decrease in bath temperature. Hardness of anodized film is rapidly increased with the flow rate being increased from 10cm/sec. It is observed that the increase in the flow rate from 11cm/sec. It is observed that the increase in the flow from 11cm/sec to 48cm/sec is more effective in enhancing the hardness of film than is the decrease in bath temperature from 1$0^{\circ}C$ to $0^{\circ}C$.