• 한국산학기술학회논문지
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• 제14권8호
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• pp.4028-4032
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• 2013

폐타이어 재활용을 위한 열분해 공법으로 발생하는 열분해 카본블랙의 재활용 방안이 필요하다. 아스팔트 바인더의 소성변형 특성을 개선하기 위하여 페타이어 열분해 공법의 부산물인 카본블랙을 이용하였다. 원아스팔트에 열분해 카본블랙 0%, 5%, 10%, 15% 및 20%를 혼합하였고, 연화점, 침입도시험, 회전점도계 및 동적전단유동기시험을 시행하였다. 열분해 카본블랙을 혼합한 아스팔트 바인더의 연화점은 증가하였고, 인화점은 기준값을 만족하였다. 135도에서의 회전점도값은 증가하였고, 소성변형에 대한 저항성이 개선되는 것으로 나타났다.

• 대한기계학회논문집
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• 제18권10호
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• pp.2706-2711
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• 1994

In this work, an experimental type of torque converter has been constructed and its characteristics have been evaluated by adapting an electrorheological fluid(ERF) as an operating medium. The device was designed by using the equations which were proposed by Carlson et al. The correlation between the rheological behaviour of an ERF and mechanical parameters of the clutch has been investigated. The torque generated by an ERF in this device is sum of one due to the yield strength by polarizing dispersed particles in dielectric oil and one due to the viscous drag. The experimental results are presented in terms of torque and current density as a function of rotational speed at various electric field strength applied. Experimental results showed that the measured torque was rapidly increased with the increase of the electric field, generally being proportional to the rotational speed of the motor. The measured current was shown to be increased with the increased electric field. Also, the current was decreased with the increase of increased with the increased electric field. Also, the current was decreased with the increase of the rotational speed of the motor and reached plateau region after f = 5 Hz.

• 한국태양에너지학회 논문집
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• 제32권4호
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• pp.9-16
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• 2012

Nanofluids using Carbon Nanotubes have a excellent thermal characteristic. In this study, for increasing the efficiency of solar collector, the thermal conductivity and viscosity of Ethanol-Oxidized Multi-walled Carbon Nanofluids were measured. Nanofluids were manufactured by ultra-sonic dispersing Oxidized Multi-walled Carbon Nanotubes(OMWCNTs) in ethanol at the rates of 0.0005 ~ 0.1 vol%. The thermal conductivity and viscosity of manufactured nanofluids were measured at the low temperature($10^{\circ}C$), the room temperature($25^{\circ}C$) and the high temperature($70^{\circ}C$). For measuring thermal conductivity and viscosity, we used transient hot-wire method and rotational digital viscometer, respectively. As a result, under given temperature conditions, thermal conductivity of the 0.1 vol% nanofluids improved 33.74% ($10^{\circ}C$), 33.14% ($25^{\circ}C$) and 32.36% ($70^{\circ}C$), and its viscosity increased by 37.93% ($10^{\circ}C$), 31.92% ($25^{\circ}C$) and 29.42% ($70^{\circ}C$) than the base fluids.

• Tribology and Lubricants
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• 제19권1호
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• pp.15-20
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• 2003

The purpose of the paper is to investigate the effects of design parameters on the noise of a rotor- bearing system supported in oil lubricated journal bearings. Effects of radial clearance and width of the bearing, lubricant viscosity and mass eccentricity of the rotor are also examined. Numerical results of the parametric studies are summarized through graph for the A-weighted sound pressure level of the bearing with respect to the rotational speed of the rotor. Results show that the sound pressure level of the bearing is markedly influenced by the mass eccentricity of the rotor and the radial clearance and the width of the bearing. The high viscosity of the lubricant slightly decreases the noise of the bearing, but its effect is relatively very low at high speed. The results of the paper could be an aid in the low noise design of rotor-bearing system supported in oil lubricated journal bearings.

• Tribology and Lubricants
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• 제3권1호
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• pp.26-30
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• 1987

두개의 Flat washer사이에 세개의 강구를 같은 거리로 놓고 아래의 Flat을 회전시킬때 고점성의 폴리부틴이 금속접촉에 미치는 영향을 조사하였다. 금속접촉은 EHD油膜두께(h), 표면밀도($\sigma$)의 비에 관계되며 Hertz 압력에서 윤활유의 점성-압력계수는 유막에 영향을 주며 따라서 h/$\sigma$에 영향을 줌을 알았다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.337-339
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• 2008

Recently, Note PCs have being widely used due to their features such as good mobility and low power consumption. In order to ensure the current market position, further improvement is required. Especially, the lower operating voltage is essential for the long operating time of Note PCs. For the achievement of lower operating voltage, possible contributions from LC materials side are to lower the viscosity and to increase the dielectric constant without sacrificing the reliability. In order to achieve lower driving voltage, new LC mixtures have been developed, optimizing theirs physical properties.

• 반도체디스플레이기술학회지
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• 제12권3호
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• pp.1-6
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• 2013

In many technical fields including electronics and display manufacturing processes, properties of coating liquids could be greatly enhanced by adding nanopowders and it requires efficient mixing techniques to achieve uniform dispersion of nanoparticles in liquids. This paper presents the three-dimensional CFD simulations on the flowfields of a highly viscous liquid in the large scale industrial mixer of impeller type. The effects of several important design and operation parameters such as impeller geometry, rotational speed, and degree of liquid viscosity are investigated to appreciate the mixing performance by examining the computational results for flow pattern of rotationally stirred liquid of high viscosity in the mixer.

• 한국환경과학회지
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• 제5권1호
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• pp.35-41
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• 1996

For studying of coagulation and sedimentation in estuarine clay, we obtained several flow curves with various concentrations of sea water by using Coutte type rotational rheometer. The initial shear stress on high concentration of sea water was observed big, but after this, its value is decreasing with increasing shear rate. The maximum pick of shear stress is decreasing with the decreasing of concentration of sea water The trend is same totally above for viscosity. The sedimentation times with the concentration of sea water vary in $\infty$ ~ 5 minutes. The zeta potential is changed dramatically between 114 and 118 concentration of sea water. That is consistent with the sedimentation graph. From these results, the phenomena of coagulation and sedimentation can be explained with viscoelastic terms on structual formation among particles by the changes of surface potential affected from contacting sea water to dispersed particles.

• 한국식품영양과학회지
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• 제28권3호
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• pp.554-558
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• 1999

Flow properties of traditional kochujang at various fermentation times(0~12 weeks) were determined with rotational cylindrical(RC) and serrated plate plate(PP) viscometer. Magnitudes of consistency index(K) of power law model and Cassson parameters(yield stress and viscosity) measured by PP viscometer were higher than those using RC viscometer. All kochujang samples during fermentation were much shear thinning with values of flow behavior index(n) as low as 0.2~0.34. K value and Casson yield stress measured by PP viscometer had good correlations(r=0.94; r=0.91) with fermentation time. No significant changes in flow model parameters measured by RC viscometer were observed for kochu jang during fermentation. Magnitudes of flow model parameters measured by PP viscometer more closely correlated with fermantation times of kochujang than did RC viscometer.

• 한국식품저장유통학회지
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• 제8권1호
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• pp.102-108
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• 2001

자색고구마 색소 농축액의 유동특성을 원뿔형 회전점도계를 사용하여 가용성 고형분의 농도 25-65% 및 온도 20-6$0^{\circ}C$의 범위에서 조사하였다. 자색고구마 색소 농축액은 뉴톤성유체의 특성을 나타냈다. 자색고구마 색소 농축액의 점도의 온도에 대한 영향은 Arrhenius 식을 따랐으며, 활성화에너지는 14.23-43.00 kJ/mol로서 농도가 증가함에 따라 직선적으로 증가하였다. 자색고구마 색소 농축액의 점도와 온도 및 농도에 대한 관계를 조사한 바, 일정한 온도에서 용액의 점도는 농도가 증가함에 따라 지수함수적으로 증가하였으며, 그 증가 정도는 온도가 낮을수록 증가하였다.