• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.39-43
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• 2007

The characteristics of the Baikkimchi sauce made from natural pigments according to the preservation period were explored. For this research, two Baikkimchi sauces were made. One was made of Baikkimchi and only side materials (Sauce I). The other was made of Baikkimchi, side materials and 1.5% of orange paprika powders (Sauce II). There was no significant change in pH and the total acidity. The color showed better stability in the sauce II, the one with the natural pigments. As the preservation period increased, vitamin C content and the viscosity decreased. In addition, the number of lactic acid bacteria became rather reduced. Sevral sensory features were different significantly according to the preservation period, and the one with source II showed better features overally.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.145-159
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• 2004

A mathematical model and its computer solution program were proposed to analyze the motion of contact lenses which are being subject to lid-blinking. The equation was derived by incorporating an acceleration induced lid's force exerting on the contact lens, the viscous damping resistance in the tear layer beneath the lens and the sliding frictional force between the lid and the contact lens surface into the formulation of differential equation describing the vibration. The model predicts the time-dependent displacement from the equilibrium postion during/after the blinking. During the blinking, as the time for the completion of one cycle of blinking decreases the off-the-equilibrium displacement of contact lens increases while the decrease of diameter in the contact cause the opposite effect. It is found that lid pressure exerting on the lens cause an insignificant lens displacement from the equilibrium position. After blinking the frequency of damped oscillation of contact lens decreases as the diameter of lens increases, due to the incresed surface while the reduced blinking time does not cause a significant frequency change. This is because that driving force for the contact lens movement posterior to blinking is the capillary-induced force not the lid force.

• Journal of Conservation Science
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• v.35 no.5
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• pp.480-493
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• 2019

In this study, the method for processing glue and glue-alum sizing from the dancheong ground treatment was evaluated with respect to weather resistance, and its effect on the conservation of dancheong was analyzed. Viscosity and pH of the glue and glue-alum specimen were measured and classified into three categories(none layer, glue layer, and glue-alum layer), which were further classified according to low concentration(four times for 2%) and high concentration(once for 10%). The base layer formation was subsequently classified into three categories based on pigment adoption, namely, Noerok(celadonite), Seokganju(terra rossa), and Jangdan(red lead). The completed specimen was subjected to a changing-environment experiment for evaluating weather resistance and observing the surface. Color variations were analyzed before and after the experiment. The results indicate that glue-alum sizing comprising 5% alum or 7% alum has strong acidity that can affect the life of dancheong, and the high level of 7% alum makes it difficult to create a solid coating layer. After ultraviolet irradiation, the specimen with 7% alum changes its color to yellow. Furthermore, after moisture absorption and drying, cracks can be observed on the entire specimen surface that corroborate the physical change. Additionally, gas-based corrosion causes marginal surface changes. Hence, the formation of a stable coating layer can be achieved by incorporating a low concentration glue solution that is almost neutral, and the application of glue-alum sizing having 2% concentration can aid in the conservation of dancheong.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1148-1156
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• 2009

In order to manufacture noodles using rice flour as its main ingredient, organic acid and thickening agents have been used, and protein, dextrin, and refined salt have added. The rice flour dough that had been baked using organic acids and thickening agent showed the max weight of $2040.00\;g/cm^2$, elasticity value of 139.12%, cohesiveness of 66.05%, chewiness of 1,396.13g, and brittleness of 190,456.12g respectively. The appropriate conditions for manufacturing rice noodle using rice flour were that the rice was to be soaked for 12 hours at temperature of $20{\sim}25^{\circ}C$ and to be milled twice at temperature lower than $35^{\circ}C$. Additionally, the most ideal condition to manufacture noodles was to use the rice flour by combining protein, dextrin and refined salt using 3.88% organic acid blend and 2.82% blend of thickening agents in order to change the rice flour properties

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.29-40
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• 2011

Warm-Mix Asphalt(WMA) technologies have been developed since 15 years ago, which are internationally and domestically concerned with energy-saving and environmental-friendly technologies in public and private sectors of highway engineering. The performance of asphalt mass is traditionally evaluated by the penetration, viscosity, or Superpave tests. This research, however, is focused more on the properties depending on asphalt film thicknesses instead of evaluating asphalt mass behaviors by those tests. For this approach, a new testing protocol and analysis method are described by the bonding properties on each film thickness. This testing method and analysis tool are borrowed from those of DSR Moisture Damage test and applied by using ARES. The analysis results indicate that there is a limit film thickness between $200{\mu}m$ and $400{\mu}m$, which causes significant changes of the properties. In addition, the results show that the property changes of Hot-Mix Asphalt(HMA) and WMA on the limit film thickness are also different. Therefore, it is suggested that the properties on thin film thicknesses between $200{\mu}m$ and $400{\mu}m$ should be considered in order to evaluate WMA properly.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.350-359
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• 2016

We performed fast pyrolysis of empty fruit bunch (EFB) in the range of temperature from $400{\sim}550^{\circ}C$ and 1.3 s of residence time. The effect of temperature on the yields and physicochemical properties of pyrolytic products were also studied. Elemental and component analysis of EFB showed that the large amount of potassium (ca. 8400 ppm) presents in the feedstock. Thermogravimetric analysis suggested that the potassium in the feedstock catalyzed degradation of cellulose. The yield of bio-oil increased with increasing temperature in the range of temperature from $400{\sim}500^{\circ}C$, while that of gas and biochar decreased and showed monotonous change each with increasing temperature. When the EFB was pyrolyzed at $550^{\circ}C$, the yield of bio-oil and char decreased while that of gas increased. Water content of the bio-oils obtained at different temperatures was 20~30% and their total acid number were less than 100 mg KOH/g oil. Viscosity of the bio-oils was 11 cSt (centistoke), and heating value varied from 15 to 17 MJ/kg. Using GC/MS analysis, 27 chemical compounds which were classified into two groups (cellulose-derived and lignin-derived) were identified. Remarkably the concentration of phenol was approximately 25% based on entire chemical compounds.

• Membrane Journal
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• v.25 no.4
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• pp.343-351
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• 2015

In this study, we synthesis polyimide with high gas selectivity using 2,2-bis(3,4-carboxylphenyl) hexafluoropropane, 2,4,6-Trimethyl-1,3-phenylenediamine (DAM) and 4,4-Methylenedianiline (p-MDA), and then the asymmetric membrane was fabricated by non-solvent phase separation method. To confirm the property change of the membrane using different solvent, we measured and compared the viscosity of the polymer solution, cloud point and non-solvent phase separation coefficient. The morphology and gas separation property of membrane prepared by phase separation method was confirmed using Field Emission Scanning Electron Microsope and the single gas permeation measurement apparatus. The single gas ($CH_4$, $N_2$, $O_2$, $CO_2$) permeation property and selectivity value of the membrane prepared with NMP was higher than the membrane prepared with DMAc. We confirmed that the gas selectivity of the membrane increased and the permeation property decreased with increasing of the solvent evaporation time.

• Korea-Australia Rheology Journal
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• v.21 no.1
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• pp.59-69
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• 2009

The prediction of pressure drop for a droplet flow in a confined micro channel is presented using FE-FTM (Finite Element - Front Tracking Method). A single droplet is passing through 5:1:5 contraction - straight narrow channel - expansion flow domain. The pressure drop is investigated especially when the droplet flows in the straight narrow channel. We explore the effects of droplet size, capillary number (Ca), viscosity ratio ($\chi$) between droplet and medium, and fluid elasticity represented by the Oldroyd-B constitutive model on the excess pressure drop (${\Delta}p^+$) against single phase flow. The tightly fitted droplets in the narrow channel are mainly considered in the range of $0.001{\leq}Ca{\leq}1$ and $0.01{\leq}{\chi}{\leq}100$. In Newtonian droplet/Newtonian medium, two characteristic features are observed. First, an approximate relation ${\Delta}p^+{\sim}{\chi}$ observed for ${\chi}{\geq}1$. The excess pressure drop necessary for droplet flow is roughly proportional to $\chi$. Second, ${\Delta}p^+$ seems inversely proportional to Ca, which is represented as ${\Delta}p^+{\sim}Ca^m$ with negative m irrespective of $\chi$. In addition, we observe that the film thickness (${\delta}_f$) between droplet interface and channel wall decreases with decreasing Ca, showing ${\delta}_f{\sim}Ca^n$ Can with positive n independent of $\chi$. Consequently, the excess pressure drop (${\Delta}p^+$) is strongly dependent on the film thickness (${\delta}_f$). The droplets larger than the channel width show enhancement of ${\Delta}p^+$, whereas the smaller droplets show no significant change in ${\Delta}p^+$. Also, the droplet deformation in the narrow channel is affected by the flow history of the contraction flow at the entrance region, but rather surprisingly ${\Delta}p^+$ is not affected by this flow history. Instead, ${\Delta}p^+$ is more dependent on ${\delta}_f$ irrespective of the droplet shape. As for the effect of fluid elasticity, an increase in ${\delta}_f$ induced by the normal stress difference in viscoelastic medium results in a drastic reduction of ${\Delta}p^+$.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.442-449
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• 2017

In this study, a method to inject small amount of activation agent from the outside of the pipeline to the inside wall of the pipe was newly proposed to enhance pumping efficiency of cementitious materials. The activation agent is injected into the slip-layer, which is generally formed in the vicinity of the inside wall of the pipe during pumping cementitous materials. Through the injections, it is expected to decrease viscosity of slip-layer, namely, the friction between the mateirals and the pipe. The proposed method was verified by lab-scale pumping tests with mortars having water to cement ratio of 47%. The tests were performed with two different type of activation agents(superplasticizer and anionic surfactant) and three different amount of the agents(0.14, 0.28, 0.42% of the mortar volume). The compressive strength were measured with and without injecting the activation agent, and the internal pressures of pipeline were measured. When the anionic surfactant was used, there was no change in the compressive strength. As the amount of anionic surfactant increased, the pumping pressure decreased up to 71.4% at the maximum.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.320-328
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• 2014

Biodiesel has very similar physical properties (density, kinematic viscosity) and has even higher cetane number compare with conventional diesel. There are no necessity to change or modify the infra-structure & engine system. It is known that fatty acid methyl ester (FAME) is oxygen-contained components increasing the combustibility, biodegradability and reduced the exhaust harmful gas. These things made the biodiesel more popular as an alternative diesel fuel. But biodiesel's sources are controversial issues about $CO_2$ reduction effect at this time because those mainly come from edible plants such as soy, palm, rapeseed already spent lot of $CO_2$ to cultivate. Whereas micro-algae is focused because they are inedible and has rapid growth rates & high carbon-dioxide adsorption rate per area. In this study, we analyze the each FAME components using $GC{\times}GC$-TOFMS in stead of GC-FID and verify the previous total FAME contents method's applicability through the micro algal biodiesel derived from Dunaliella tertiolecta.