• 한국자동차공학회논문집
• /
• 제19권3호
• /
• pp.130-137
• /
• 2011

Experimental investigations are conducted to figure out the feasibility of $Al_2O_3$ nanofluids as the alternative coolant for car engine. For the purpose, the thermal conductivities and viscosities of water/commercial coolant based $Al_2O_3$ nanofluids with 0.3, 1.0, 2.0 and 3.0 vol. % at temperatures ranging from $25^{\circ}C$ to $35^{\circ}C$ are measured. Thermal conductivities are measured using the transient hot-wire method and also viscosities are measured by Brookfield LVDV-III rheometer. Based on the results, it is shown that thermal conductivity of $Al_2O_3$ nanofluids with 3.0 vol. % is increased about 11% at $35^{\circ}C$ and the increment of viscosity approaches to 84% at shear rate of 600(1/s) and 80% at shear rate of 960(1/s) in the same temperature. with fundamental data for the thermal conductivity and viscosity of the nanofluids, the feasibility of $Al_2O_3$ nanofluids as the alternative coolant for car engine are discussed.

• 한국분말재료학회지
• /
• 제27권6호
• /
• pp.484-489
• /
• 2020

In this study, acoustic and viscosity data are collected in real time during the ball milling process and analyzed for correlation. After fast Fourier transformation (FFT) of the acoustic data, changes in the signals are observed as a function of the milling time. To analyze this quantitatively, the frequency band is divided into 1 kHz ranges to obtain an integral value. The integrated values in the 2-3 kHz range of the frequency band decrease linearly, confirming that they have a high correlation with changes in viscosity. The experiment is repeated four times to ensure the reproducibility of the data. The results of this study show that it is possible to estimate changes in slurry properties, such as viscosity and particle size, during the ball milling process using an acoustic signal.

• 대한화학회지
• /
• 제54권1호
• /
• pp.71-76
• /
• 2010

298.15~318.15 K 온도에서 디지탈 진동 U-tube densimeter 와 Ubbelohde 모세관 점성계을 사용하여 2-브로모프로판/메탄올 이성분 혼합물의 밀도와 점성도를 측정하였다. 온도와 농도에 대한 밀도와 점성도 상호 의존 관계를 조사하였다. 이성분 혼합물의 여분 몰부피와 여분 점성도를 실험으로 얻어진 밀도와 점성돌로부터 계산하여 구하였다. 모델이 실험치와 잘부합됨을 발견하였다.

• 한국식생활문화학회지
• /
• 제28권3호
• /
• pp.312-319
• /
• 2013

This study investigated the quality of noodles containing different amounts of Lagocephalus lunaris powder (LLP). Noodles were prepared at ratios of 0, 1, 3, 5 and 7% LLP based on flour weight, after which cooking quality, mechanical texture properties, and viscosity were measured, and a sensory evaluation was performed. The gelatinization points of the composite LLP-wheat flours were shown to increase. Additionally, measurement of the viscosity at 95, viscosity at 95 after 15 minutes, and the maximum viscosity values decreased, as the LLP content increased. As increasing amounts of LLP were added, the L and a values decreased, whereas the b value increased and the color values, weight, and volume of cooked noodle increased, as did the turbidity of the soup. Finally the LLP additive increased hardness and decreased adhesiveness, cohesiveness and springiness. Sensory evaluation showed that high quality cooked noodle could be produced by inclusion of 5% LLP.

• 한국식품조리과학회지
• /
• 제22권2호
• /
• pp.173-180
• /
• 2006

This study evaluated the quality characteristics of dried noodles made of wheat flour with different concentrations of Dioscorea japonica flour. Cooking quality, mechanical texture properties and viscosity were measured, and sensory evaluation was performed with the prepared noodles. Water binding capacity, solubility and swelling power of the composite Dioscorea japonica flour-wheat flours were higher than those of pure wheat flour. Gelatinization points of the composite Dioscorea japonica flour-wheat flours were increased and initial viscosity at $95^{\circ}C$, viscosity at $95^{\circ}C$ after 15 minutes and maximum viscosity of these composites were decreased, with increasing Dioscorea japonica flour content, as measured by amylograph. With increasing Dioscorea japonica flour content, L and b values were decreased, but a value was increased, for the color values, while weight and volume of the cooked noodles and turbidity of the soup were increased. For the textural characteristics, the addition of Dioscorea japonica flour increased the hardness and decreased the adhesiveness, cohesiveness and springiness. Overall, the noodles made with 10% Dioscorea japonica flour were preferred more than the other noodles, as tested by sensory evaluation.

• 한국주조공학회지
• /
• 제30권6호
• /
• pp.241-246
• /
• 2010

The viscosity of foam metal is necessary to get the pores, but it is difficult to manufacture net-shape foam, because the fluidity decreases by increasing viscosity. In this study, the A356 alloy which has good fluidity and less defect was selected and fabricated to foam metal. To understand about effect of thickening agent on foaming and mechanical properties, quantity of thickening agent was changed. The pore size, porosity and distribution of foam metal were measured by i-solution program. And compression test were performed by UTM. In case of 3.0wt% Ca in thickening agent, it is found that most of foam consist of homogeneous shape, and the growth height had the highest value of 204 mm in the all fabricated foams. The porosity was 93% and compressive strength was 3.1 MPa. In the microstructure, the $Al_2Si_2Ca$ intermetallic compound and Ti were observed. The vickers hardness value rose with increasing viscosity value.

• 한국분무공학회지
• /
• 제16권3호
• /
• pp.140-145
• /
• 2011

Gelled propellants are non-Newtonian fluids in which the viscosity is a function of the shear rate, and they have a high dynamic shear viscosity which depends on the amount of gelling agent contents. The present study has focused on the breakup process, wave development of ligament and liquid sheets formed by impinging jets with various gelling agent contents. The breakup process of like-on-like doublet impinging jets are experimentally characterized using non-Newtonian liquids. The spray shape with elliptical pattern is distributed in a perpendicular direction to the momentum vectors of the jets. Gelled propellant simulants with high viscosity jets are more stable and produce less pronounced surface waves than low viscosity jets. Gelled propellant simulants from like-on-like doublet impinging jets have the spray shape of closed rim patterns at low pressure. As the injection pressure increased, rimless patterns which were composed of ligament sheets and small droplets emerged due to the effect of the aerodynamic action.

• E2M - 전기 전자와 첨단 소재
• /
• 제8권5호
• /
• pp.587-593
• /
• 1995

Silicone oils used insulating substances exhibit the both of organic and inorganic properties, and it has many superior characteristics such as the high thermal resistance and low thermal oxidation level when compared to other insulation oils. In order to investigate the dielectric loss due to the increase of viscosity, silicone oils of viscosity 1, 2, 5[cSt] had been chosen as the specimen and experiment has been performed in the temperature range of -70[.deg. C] - 65[.deg. C] and frequency range of 30 - 1*10$\^$5/[Hz]. As a result, the linear decrease of loss at low frequency region in high temperature was due to the influence of applying frequency, whereas the increase of loss at high frequency region was contributed by electrode's resistance. And increasing viscosity, the activation energy increased from 3.77[kcal/mole] to 7.21[kcal/mole]. The dipole moment of specimen was become clear 1.48 - 2.26[debyel in high temperature region(5 - 65[.deg. C]) and 1.05 - 1.80[debye] in low temperature region (-70 - -25[.deg. C])respectively.

• 설비공학논문집
• /
• 제19권8호
• /
• pp.593-598
• /
• 2007

The present study has dealt with the measuring method of ice slurry viscosity using falling sphere viscometer. The experimental apparatus was composed by test section and high-speed video system. And the spheres used in this study were alumina and glass. The main parameters were ice packing factor (IPF) and falling velocity of sphere so the acquired results were discussed for these parameters. The viscosity of ice slurry was calculated by using measured falling velocity and moving distance at instantaneous time and the Stokes hypothesis was used for this calculation. It was clarified that possible measuring range was $IPF\;=\;0.06{\sim}0.14$ of this type of measuring device and measuring method. In addition, it was clarified that the viscosity of ice slurry increased to increase of ice packing factor (IPF) of ice slurry.

• 한국식품영양학회지
• /
• 제12권3호
• /
• pp.252-257
• /
• 1999

In an attempt to evaluate the effects of calcium on paste or gelatinization properties by amylograph and mixing properties by farinograph of wheat flour and on viscosity property cooking quality textural and sensory properties of Ramyon were examined. The contents of calcium used were from 1.0% to 3.0% based on flour weight. The viscosity property of wheat flour with calcium was increased the initial past-ing temperature but the amylograph peak viscosity were decreased in vice versa. The farinograph absorp-tion stability and breakdown were increased by calcium. The shear extrusion force and hardness of Ram-yon manufactured with calcium were shown much higher value than those of control. At cooking quality examination of Ramyon manufactured with calcium weight of cooked Ramyon was increased by volume was decreased. Extraction amounts of Ramyon manufactured with calcium during cooking were much smaller than those of control. These changes will provided many advantages in the preparation of Ram-yon. The I2 reaction value of Ramyon manufactured with calcium and control were shown to almost same values. Sensory properties of cooked Ramyon which was manufactured with calcium showed quite acceptable. Based on the cooking and sensory evaluation test addition of 0.3% calcim to wheat flour may be suitable for processing Ramyon.