• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.44-51
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• 2003

By blending of various low boiling point oxygenated agents to lower grade fuels, significant improvements were simultaneously obtained in smoke, CO, PM, SOF and BSEC. Especially, our trends were remarkably obtained by retarding injection timing, by decreasing boiling point and increasing blending contents of additives in case of oxygenated agents rather than non-oxygenated agents. Also, it was revealed that when 20vo1.% DMM added to high viscosity fuels and injection timing was retarded, NOx-smoke trade off relationship was much better than that of ordinary diesel fuel. Thus, lower grade fuels with high viscosity could be expected to be used efficiently and cleanly in diesel operation by blending low boiling point oxygenates.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.12
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• pp.847-851
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• 2014

The characteristics of dielectric constant and $tan{\delta}$ of low viscosity silicone oils with changing degree of polymerization were investigated. The result shows dipole loss mechanism at low temperature range. The dielectric loss in the range of low frequencies are predominantly of ionic nature with temperature increase. The peak of dielectric loss is the detrapping of the electrons which is were trapped in the localized level of the silicone oils at the frequency of 30 kHz. The increase of ionic conduction is attributed to the presence of ionizable oxidation products and their increased dissociation feature. The activation energy ${\Delta}H$ and dipole moment ${\mu}_d$ were increased whit increasing degree of polymerization.

• Journal of the Korean Ceramic Society
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• v.43 no.3 s.286
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• pp.148-151
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• 2006

In order to examine the process parameters for the vitrification of Low and Intermediate Level radioactive Waste (LILW) generated from nuclear power plants, measurements of several melt properties was performed for four selected glasses containing simulated waste. Electrical conductivity and viscosity were determined at temperatures ranging from 1123 to $1673^{\circ}C$. The temperature dependences of both properties in the molten state showed a similar behavior in which their values decrease as the temperature increases. The values of the electrical conductivity and viscosity at a temperature of 1423K adopted in an induction cold crucible melter process were $0.27{\sim}0.42$ S/cm and $9.8{\sim}42$ dPas, respectively.

• Journal of computational fluids engineering
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• v.14 no.1
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• pp.78-85
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• 2009

A combined theoretical and numerical study is conducted to design a slit nozzle for large-area liquid coating. The objectives are to guarantee the uniformity in the injected flow and to provide the capability of explicit control of flow rate. The woking fluid is a dilute aqueous solution containing single-walled carbon nanotubes and its low viscosity and the presence of dispersed materials pose technical hurdles. A theoretical analysis leads to a guideline for the geometric design of a slit nozzle. The CFD-based numerical experiment is employed as a verification tool. A new flow passage unit, connected to the nozzle chamber, is proposed to permit the control of flow rate by using the commodity pressurizer. The numerical results confirm the feasibility of this idea. The optimal geometry of internal structure of the nozzle has been searched for numerically and the related issues are discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.733-738
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• 2008

Due to environmental concerns $CO_2$ has been reintroduced as a potential candidate to replace HFCs in refrigeration systems. Oils are always required in a vapor-compression cycle, and thus it is necessary to precisely estimate the thermodynamic mixture properties of $CO_2$-lubricant oil. In the present study, the density and the viscosity of the mixture was calculated by the Redlich and Kwong type EoS and the modified Peng and Robinson type viscosity EoS, respectively. The viscosity model was based on the similarity between P-v-T and T-$\mu$-P relationships. The predicted results were compared with the experimental data of Pens ado et al. whose test conditions were 100$\sim$650 bar of pressure and 303 K$\sim$353 K of temperature with the $CO_2$-POEs mixtures under 92.2 wt.% and 83.3 wt.% of $CO_2$ concentration. The mean deviations of the mixture density were 7.93% and 8.32% for 92.2 wt.% and 83.3 wt.% of $CO_2$ concentration, respectively. Concerning the viscosity, the mean deviations were 4% and 10% for 92.2 wt.% and 83.3 wt.% of $CO_2$ concentration under the Pensado et al.'s test conditions.

• Journal of Nutrition and Health
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• v.26 no.6
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• pp.793-803
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• 1993

This study was designed to measure viscosity, osmolality and in vitro flow rates via nasogastric tubes for 6 types of commercially available and 9 hospital-blenderized enteral solutions and to examine the effect of viscosity and osmolaility of enteral formula on the flow rates in gravity drip administration. Each solution was infused through 18, 16, 14, 12 French sizes of silicone rubber tube. Flow rates were measured six times at $25^{\circ}C$ using formula bags and drip sets hung at a uniform height on a intravenous drip stand with tube uniformly positioned in collecting container. Viscosity ranged widely from 16.0 to 195.5 cps with mean, 64.61$\pm$64.42 for hospital-blenderized formula while mean viscosity of commercial formula was 7.60$\pm$4.84 cps. Mean osmolality of commercial formula and hospital-blenderized formula were 370$\pm$100.80, 540.33$\pm$89.37 mOsm/kg respectively. There was negative relationship between viscosity of formula and flow rates through tubes but no significant relationship between flow rates and osmolalty. Some of hospital-blenderized formula was too viscous to be infused througth tube with gravity drip administration and the recipe of formula requires to be modiifed. On the other hand, commercial formula with the low viscosity flows too rapidly with large bore size tubes. Smaller size of tube must be selected for hyperosmolar solution to decrease possible side effects associated with tube feeding. Two kinds of regression equations for flow rates obtained according to viscosity and tube sizes were also presented for the purpose of practical uses. In conclusion, this study emphasizes that viscosity of fomula, osmolality, patient's tolerance and comfort, caloric density should be considered in the selection of tubes for gravify drip administration.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.2
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• pp.145-155
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• 2004

From the cooking data, Japanese rice showed higher water uptake but lower expansion volume, pH and iodine blue value than those of Korean rice. Japanese rice had higher maximum viscosity, breakdown viscosity and pasting temperature but lower final viscosity and setback viscosity than those of Korean rice by RVA analysis. Japanese rice had higher LC (low compression) hardness, U stickiness and HC (high compression) stickiness, LC balance and HC balance, but had lower HC hardness and thickness in the tensipresser data. Also Japanese rice had higher stickiness and balance, and lower hardness from the texturometer analysis. Japanese rice showed higher a cooked taste score than that of the Satake cooked taste machine. The various mean values of Japanese rice after cooking showed better cooking characteristics than the Korean rice. These results might be caused because Japanese rice had a little lower amylose and protein content, but higher tat acidity content.

• Transactions of Materials Processing
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• v.11 no.4
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• pp.349-354
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• 2002

In order to find the effect of lubricant viscosity, sheet surface roughness, tool geometry, and forming speed on the frictional characteristics in sheet metal forming, a sheet metal friction tester was designed and manufactured and friction test of various sheet were performed. Friction test results showed that as the lubricant viscosity becomes lower, the friction coefficient is higher. When surface roughness is extremely low or high, the friction coefficient is relatively high. The result also show that as the punch radius and punch speed becomes bigger, the friction coefficient is smaller. Using experimental results, the mathematical expression between friction coefficient and lubricant viscosity, surface roughness, punch comer radius, or punch speed is also described.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.2
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• pp.23-36
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• 2004

The surface tension method has been possible only for the low viscosity materials. However, the inks for the off-set lithography and intaglio should have high viscosity and high tack. In this paper, we propose the elongation method to estimate the surface tension of high viscosity printing inks. The elongation method could be more useful to estimate the surface tension and shown in this research, it is possible to calculate the surface tension of high viscoxity ink without diluting the sample.

• Proceedings of the KWS Conference
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• 2000.10a
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• pp.256-259
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• 2000

High viscosity mixing powder is a very useful material for laser cladding. This material has a high viscosity so that it can be sticked to substrate. Therefore, Laser cladding can be performed on a curved or slope surface. Laser cladding can be easily performed with the material instead of wire that is difficult to be manufactured in some case. In this experiment, it was used a high viscosity mixing powder which consists of a high temperature flux and a bronze powder. And AC2B alloy material was used as a substrate. Flux prevents the clad layer from being oxidized and increases bonding property between substrate and cladding material. It makes possible to laser cladding at low level energy.