• KSBB Journal
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• v.5 no.3
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• pp.235-240
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• 1990

A quantitative physiological approach has been employed to estimate the metabolic parameters such as specific uptake rates of nutrients and specific production rate in continuous culture of Pseudomonas elodea for gellan gum production. The estimated values of metabolic parameters are used for process improvement. During the exponential growth phase, the specific growth rate was 0.16hr-1 in batch culture. The gellan gum concentration increased up to 0.7g dry weight/100g broth and the apparent viscosity of the culture broth was about 4,500 cp.(72hrs culture). The ratio of specific uptake rate of carbon to that of nitrogen were found to be optimum at about 3.0mg-carbon/mg-nitro-gen. With the improved medium, the maximum gellan production rate, 0.6g dry weight/1/hr, was obtained at D=0.14 hr-1. The shear stresses of culture broth were fairly well correlated with shear rates by using Casson equation and at highly viscous culture broth, oxygen transfer coefficient was greatly reduced.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.114-122
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• 2010

Hydroxy fatty acids have gained important attentions because of their special properties such as higher viscosity and reactivity compared to non-hydroxy fatty acids. The new bacterial isolate Pseudomonas aeruginosa (PR3) had been well studied to produce mono-, di-, and tri-hydroxy fatty acids from different unsaturated fatty acids. Of those hydroxy fatty acids, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was produced with high yield from oleic acid by P. aeruginosa PR3. Mostly, the substrates used for the production of hydroxy fatty acid by microorganisms were free fatty acids or synthetic lipids. However, it is highly plausible to use vegetable oils containing oleic acid such as olive oil for DOD production by P. aeruginosa PR3. As a first step to address the utilization of olive oil as a substrate for DOD production, we tried to determine the effect of vessel type on DOD production from olive oil by P. aeruginosa PR3. Of two different flask types of normal flask and baffled-flask, baffled-flask was highly effective for DOD production with all the media tested. Maximum increase of productivity by baffled-flask represented 221% with the medium supplemented with whey powder instead of lactose. Results from this study demonstrated that vessel type and medium composition could be both significant factors for DOD production from olive oil by P. aeruginosa PR3.

• Journal of Biosystems Engineering
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• v.25 no.6
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• pp.481-488
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• 2000

This study was initiated in order to find alternative fuel substituting for light oil the most common fuel for heating greenhouse. The tire oil used in this research was produced by pyrolysis process, one of the final products besides steel string and carbon black in which waste tires as a form of chopped pieces broken by shredding machine are heated up to 200~30$0^{\circ}C$ with maximum restraining of oxygen supply. In order to justify light oil equivalent qualities in tire oil combustion characteristics were defined in the way of comparing kinetic viscosities in the wide range of temperature flame sizes and exhaust gas components in the various combustion conditions. We found that kinetic viscosity of tire oil was lower than light oil by 1 to 2 cSt in the temperature range showing better flowing mobility in the fuel line of the burner and no significant difference in flame size between the two oils in the all combustion treatments. However much more NO and SO$_2$ were detected from the exhaust gases of tire oil than light oil combustions. In fact tire oil contains more nitrogen and total sulfur, by 25 times and 40 times respectively than light oil according to the composition analysis. Tolerable limit for SO$_2$discharge amount defined by the national air pollution standards is under 540ppm so tire oil combustion satisfies the requirement though. It is desirable if sulfur and nitrogen filtering process shall be added in the tire oil production line. Except the exhaust gas components all greenhouse heating qualities of tire oil including hot air temperature are very identical to those of light oil.

• Tunnel and Underground Space
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• v.23 no.6
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• pp.470-479
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• 2013

Hydraulic fracturing is used as a method for promoting the fluid flow in the rock and, in the energy field such as geothermal development and the development of sales gas, many studies has been actively conducted. In many cases, hydraulic fracturing is not performed in isotropic rock and especially in the case of sedimentary rocks, hydraulic fracturing is conducted in the transverse isotropic rock. The direction of the crack growth on hydraulic fracturing does not necessarily coincides with the direction of maximum principal stress in the transverse isotropic rock. Therefore, in this study, bonded particle model with hydro-mechanical coupling analysis was adopted for analyzing the characteristics of hydraulic fracturing in transverse isotropic rock. In addition, experiments of hydraulic fracturing were conducted in laboratory-scale to verify the validity of numerical analysis. In this study, the crack growth and crack patterns showed significant differences depending on the viscosity of injection fluid, the angle of bedding plane and the influence of anisotropy. In the case of transverse isotropic model, the shear crack growth due to hydraulic fracturing appeared prominently.

• Journal of Sensor Science and Technology
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• v.16 no.5
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• pp.325-330
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• 2007

For the application to optic devices, wafer level package including spacer with particular thickness according to optical design could be required. In these cases, the uniformity of spacer thickness is important for bonding strength and optical performance. Packaging process has to be performed at low temperature in order to prevent damage to devices fabricated before packaging. And if photosensitive material is used as spacer layer, size and shape of pattern and thickness of spacer can be easily controlled. This paper presents polymer bonding using thick, uniform and patterned spacing layer of SU-8 2100 photoresist for wafer level package. SU-8, negative photoresist, can be coated uniformly by spin coater and it is cured at $95^{\circ}C$ and bonded well near the temperature. It can be bonded to silicon well, patterned with high aspect ratio and easy to form thick layer due to its high viscosity. It is also mechanically strong, chemically resistive and thermally stable. But adhesion of SU-8 to glass is poor, and in the case of forming thick layer, SU-8 layer leans from the perpendicular due to imbalance to gravity. To solve leaning problem, the wafer rotating system was introduced. Imbalance to gravity of thick layer was cancelled out through rotating wafer during curing time. And depositing additional layer of gold onto glass could improve adhesion strength of SU-8 to glass. Conclusively, we established the coating condition for forming patterned SU-8 layer with $400{\mu}m$ of thickness and 3.25 % of uniformity through single coating. Also we improved tensile strength from hundreds kPa to maximum 9.43 MPa through depositing gold layer onto glass substrate.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.952-958
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• 2004

Effects of normal (non-waxy) and waxy millet flours on properties of sponge cake were examined. Total dietary fiber contents of normal and waxy millets were 5.04 and 5.12%, respectively, while that of soft wheat flour was 2.23%. Alkaline water retention capacity value generally increased with addition of normal and waxy millet flours, whereas peak, minimum, and final viscosities decreased. Mixing time and mixing height decreased with addition of millet flour. Lightness of cake crust increased with addition of normal millet flour, whereas it decreased with addition of waxy millet flour, tightness of cake crumb decreased as the amount of normal and waxy millet flours increased. Increasing proportions of normal and waxy millet flours resulted in significantly decreased loaf volume. Replacement of 10% wheat flour by both normal and waxy millet flours did not significantly affect characteristics of sponge cake, but addition of more than 20% millet flour resulted in significant differences in quality characteristics.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.441-446
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• 1988

Alkaline treatment during preparation of anchovy extracts was studied for its changes in some of the physicochemical and sensory qualities. The dried anchovy was blended in 0-0.5N NaOH solutions and then incubated at $60^{\circ}C$ for 6 hours. After extraction the suspensions were neutralized and centrifuged. The results showed that the yields of solids and protein were increased by 3-5 fold of those of water extract as alkaline concentration and treatment time increased. The intrinsic viscosity showed little changes for the extracts prepared with 0-0.2N NaOH solution while the extracts prepared with over 0.3N NaOH resulted a initial small decrease followed by a rapid increase to the maximum point. The changes in color expressed as Hunter 'L', 'a' and 'b' values showed that the L value increased rapidly until 3 hours of treatment followed by a decrease, and 'a' and 'b' values were increased a little. The intensities of odor and taste were markedly increased by 2-3 fold for all of the descriptions investigated where clam-like odor and taste and sea complex odor were particularly significant.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1064-1069
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• 1998

Tetrasodium polyphosphate peroxidate (TPP) increased the farinograph stability, maximum resistance by extensigraph and amylograph peak viscosity of a noodle flour produced from Australian Standard White wheat (protein 8.76%, ash 0.380%) at concentration of $0.2{\sim}0.4%$ based on flour weight. The addition of 0.3% TPP increased the moisture content of Kalguksoo, handmade fresh noodle, by 1.5%. No significant differences however were observed in cooking properties. Sensory evaluation revealed that the color, texture and preference of cooked noodle were significantly better in the presence of TPP. The fresh noodle with 0.3%, TPP delayed the development off-flavor by 7 hr during storage at $20^{\circ}C$ and $25^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.405-409
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• 2003

This study was conducted to evaluate quality characteristics of noodles containing barley flour and ${\beta}$-glucan enriched fraction. Compared to 100% wheat flour, composite flours containing barley flour and ${\beta}$-glucan enriched fraction decreased initial pasting temperature and increased maximum peak viscosity. The noodles containing ${\beta}$-glucan enriched fraction exhibited somewhat darker color and lower values in cooked weight, volume, moisture content, and cooking loss. From the textural properties measured by texture analyzer, the noodles with 30% barley flour and ${\beta}$-glucan enriched fraction were similar to 100% wheat noodle in springiness value and significantly higher in gumminess, hardness, and chewiness. The results of sensory evaluation indicated that barley flour or ${\beta}$-glucan enriched fraction at levels up to 30% could be substituted for wheat flour without seriously depressing noodle quality. Cooking of raw noodle with ${\beta}$-glucan enrichment slightly increased total, insoluble, and soluble ${\beta}$-glucan content.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.498-503
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• 1988

Rice and rice flour were stored at $13^{\circ}C$, room temperature$(17-28^{\circ}C)$ and $38^{\circ}C$ for six months and the changes in physicochemical and organoleptic qualities were investigated to determine the preservability. Fat acidity increased rapidly up to 60 days at room temperature and 45 days at $38^{\circ}C$ and thereafter it increased slowly. At $13^{\circ}C$, it increased constantly and slowly throughout the storage. In the changes of Hunter's color for the rice and rice flour, L-value was decreased, but ${\Delta}\;E-Value$ was increased. In amylograph properties, initial pasting temperature, maximum viscosity and breakdown were all increased. Quality of stored rice was a little superior to rice flour, but there were not significantly different among them.