• The Korean Journal of Food And Nutrition
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• v.29 no.2
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• pp.186-199
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• 2016

The purpose of this study was to determine the optimal composite recipe of rice muffins with 3 concentrations of Spergularia marina L. Griseb, sugar and grape seed oil, using central composite design. In addition, the mixing condition of rice muffins was optimized by subjecting it to sensory evaluation and mechanical and physicochemical analysis using response surface methodology (RSM). In regard to its antioxidant effects, Spergularia marina L. Griseb had a total phenol and flavonoid contents and DPPH free radical scavenging activity of 17.03 mg/g, 5.13 mg/g and 17.21%, respectively. The results of mechanical and physicochemical analysis showed significant values for lightness, redness, yellowness, hardness, springiness, chewiness, gumminess, cohesiveness, height, volume, weight, specific volume, loss rate, pH, moisture, sweetness and saltiness (p<0.05), and the results of sensory evaluation showed significant values for color, flavor, taste, softness, appearance and overall quality (p<0.05). As results, optimal sensory ratio was found to be 6.69 g of Spergularia marina L. Griseb, 41.89 g of sugar and 30.48 g of grape seed oil.

• The KSFM Journal of Fluid Machinery
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• v.10 no.6
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• pp.17-23
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• 2007

In the present work, flow analysis has been performed in the steam turbine bypass control valve (single-path type) for two different cases i.e., case with steam only and case with both steam and water. The numerical analysis is performed by solving three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations. The shear stress transport (SST) model and $k-{\varepsilon}$ model are used to each different case as turbulence closure. Symmetry condition is applied at the mid plane of the valve while adiabatic condition is used at the outer wall of the cage. Grid independency test is performed to find the optimal number of grid points. The pressure and temperature distributions on the outer wall of the cage are analyzed. The mass flow rate at maximum plug opening condition is compared with the designed mass flow rate. The numerical analysis of multiphase mixing flow(liquid and vapor) is also performed to inspect liquid-vapor volume fraction of bypass valve. The result of volume fraction is useful to estimate both the safety and confidence of valve design.

• Fibers and Polymers
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• v.3 no.4
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• pp.159-168
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• 2002

Polyurethane foams were produced by using a homogenizer as a mixing equipment. Effects of stirring speed on the foam structure were investigated with SEM observations. Variation of the bubble size, density of the foam, compressive strength, and thermal conductivity were studied. A hybrid foam consisting of polyurethane foam and commercial polystyrene foam is produced. Mechanical and thermal properties of the hybrid foam were compared with those of pure polyurethane foam. Advancement of flow front during mold filling was observed by using a digital camcorder. Four types of mold geometry were used for mold filling experiments. Flow during mold filling was analyzed by using a two-dimensional control volume finite element method. Variation of foam density with respect to time was experimentally measured. Creeping flow, uniform density, uniform conversion, and uniform temperature were assumed for the numerical simulation. It was assumed for the numerical analysis that the cavity has thin planar geometry and the viscosity is constant. The theoretical predictions were compared with the experimental results and showed good agreement.

• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.167-172
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• 2006

Submicron colloidal silica coated with ceria were prepared by mixing of silica and nano ceria particles and modified by hydrothermal reaction. The polishing efficiency of the ceria coated silica slurry was tested over oxide film on silicon wafer. By changing the polishing pressure in the range of $140{\sim}420g/cm^2$ with the ceria coated silica slurries in $100{\sim}300nm$, rates, WIWNU and friction force were measured. The removal rate was in the order of 200, 100, and 300 nm size silica coated with ceria. It was known that the smaller particle size gives the higher removal rate with higher contact area in Cu slurry. In the case of oxide film, the indentation volume as well as contact area gives effect on the removal rate depending on the size of abrasives. The indentation volume increase with the size of abrasive particles, which results to higher removal rate. The highest removal rate in 200 nm silica core coated with ceria is discussed as proper combination of indentation and contact area effect.

• Journal of Radiation Protection and Research
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• v.45 no.3
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• pp.142-146
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• 2020

Background: Tritium (³H) analysis in groundwater was difficult because of its low activity. Therefore, the electrolytic enrichment method was used. To improve the detection limit and for performing simple analysis, a high-volume counting vial with the available liquid scintillation counter (LSC) was investigated. Further, it was compared with a conventional 20-mL counting vial. Materials and Methods: The LSC with the electrolytic enrichment method was used ³H analysis in groundwater. A high-volume 145-mL counting vial was compared with a conventional 20-mL counting vial to determine the counting characteristics of different LSCs. Results and Discussion: When a Quantulus LSC was used, the counting window between channels 35 and 250 was used. The background count was approximately 1.86 cpm, and the counting efficiency increased from 8% to 40% depending on the mixing ratio of the volume of sample and cocktail solution. For LSC-LB7, the optimum counting window was between 1 and 4.9 keV, which was selected by the factory (Hitachi Aloka Medical Ltd., Japan) by considering quenching using a standard external gamma source. The background count of LSC-LB7 was approximately 3.60 ± 0.29 cpm when the 145-mL vial was used and 2.22 ± 0.17 cpm when the 20-mL vial was used. The minimum detectable activity (MDA) of the 20-mL vial was greater for LSC-LB7 than for Quantulus. The MDA with the 145-mL vial was improved to 0.3 Bq/L when compared with the value of 1.6 Bq/L for the 20-mL vial. Conclusion: The counting efficiency when using the 145-mL vial was 27%, whereas it was 18% when using the 20-mL vial. This difference can be attributed to the vial volume. The figure of merit (FOM) of the 145-mL vial was four times greater than that of the 20-mL vial because the volume of the former vial is approximately seven times greater than that of the latter. Further, the MDA for ³H decreased from 1.6 to 0.3 Bq/L. The counting efficiency and FOM of LSC-LB7 was slightly less than those of Quantulus when the 20-mL vial was used. The background counting rate of the Quantulus was lower than that of the LSC-LB7.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.156-162
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• 2017

Recently, researches on High-Volume Fly ash Cement(HVFC), which is replacing high portion of cement to fly ash, have been actively conducted to reduce $CO_2$ formation. Though HVFC has various advantages, low strength development in early ages is pointed out as the biggest problem in the application of fly ash. In order to overcome such limitations, this study investigated the hydration and compressive strength characteristics of HVFC paste depending on the fly ash content with the mixing ratio varying from 0 to 80 %. Experimental results show that the HVFC paste with low water-binder ratio can overcome the limitation of low compressive strength at early ages. Also, from the result of heat flow delay, 50 % of fly ash weight ratio was the critical point of the filler effect.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.109-116
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• 2014

The flexural behavior test of UHPC segmental box girder which has 160 MPa compressive strength and 15.4 m length was carried out. The effect of steel fibers in combination with reinforcing bars on improving the ductile performance of UHPC box girder was evaluated by comparing the flexural behavior of the UHPC segmental box girders made by the two kinds of mixing portion. The test variables are volume fraction of steel fibers and the arrangement of reinforcing bars. The behavior of UHPC box girder BF2 composed of 1% volume fraction of steel fibers and longitudinal reinforcing bars in web and upper flange with stirrup showed the similar ductile behavior with the girder BF1 composed of 2% volume fraction without stirrup in elastic stress region. But BF1 had the better stiffness and showed the more ductile behavior in inelastic stress region. Segmental interfaces of UHPC box girder have not any crack and slide until the final flexural collapse load.

• The Korean Journal of Food And Nutrition
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• v.19 no.4
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• pp.381-391
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• 2006

The rheological properties of dough made the substitution of wheat flour(composite flour) at the levels of 0%, 5%, 10% and 15% soymilk residue flour, with addition of vital wheat gluten at the levels of 3, 6 and 9% were investigated. And nutrition contents of soymilk residue flour were analyzed. The results were as follows; Principal components of soymilk residue flour were 22.0% crude protein, 13.2% crude lipid, 54.3% carbohydrate, 27.2% dietary fiber and $220{\mu}g/g$ isoflavones. Free amino acid component of soymilk residue were L-glutamic acid, L-leucine, L-lysine, L-valine, L-phenylalanine, L-isoleucine, L-threonine, L-methionine and L-cystine. Total dietary fiber content of bread with soymilk residue and wheat flour were 5% soymilk residue; 3.50%, 10% soymilk residues; 4.65%, 15% soymilk residues; 5.96%, and wheat flour bread: 2.1% respectively Mixing water absorption capacity was increased by increasing amounts of added soymilk residue and vital wheat gluten. Dough development time was increased by increasing amounts of added soymilk residues, while decreased by increasing amounts of vital wheat gluten. The dough volume of composite flour with 5%, 10% and 15% soymilk residue flour were the smaller than wheat flour dough. But the dough volume was increased by added vital wheat gluten, and the composite flour with 5% soymilk residue flour and 9% vital wheat gluten was better than the others. This study proved that the dough volume of composite flour with 5% soymilk residue flour and 9% vital wheat gluten was better than the others. On the other hand, the soymilk residue flour contains dietary fiber, isoflavone, protein, lipid and carbohydrate. Therefore the soymilk residue flour will be very useful as food material.

• Preventive Nutrition and Food Science
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• v.11 no.3
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• pp.243-252
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• 2006

White salted noodles and pan bread were prepared from Korean wheats with 1Dx2.2+1Dy12 subunits in high molecular weight glutenin subunits (HMW-GS) to evaluate the suitability for end-use products through the comparison with US wheats with various classes and commercial wheat flours. Korean wheat flours with 1Dx2.2+1Dy12 subunits showed higher SDS sedimentation volume than US wheat flours with similar protein content. Compared to wheat flours with similar protein content and SDS sedimentation volume, water absorption percent of Korean wheat flours using a mixograph was higher than that of US wheat flours, but similar to commercial wheat flours. Mixograph mixing time was similar to hard wheat flours and commercial noodle flours. Optimum water absorption percent of noodle dough from Korean wheat flours was higher than that of US wheat flours. Noodle sheets from Korean wheat flours with 1Dx2.2+ 1Dy12 subunits showed lower L values, higher a values and similar b values compared to commercial noodle flours. Hardness of cooked noodles from Korean wheat flours 1Dx2.2+1Dy12 subunits correlated positively with protein content, NIRS hardness, mixograph water absorption and gluten yield of flours. Korean wheat flours with 1Dx2.2+1Dy12 subunits showed lower loaf volume and harder crumb firmness than hard wheat flours and commercial bread wheat flours in spite of similar protein quantity and quality to hard wheat flours.

• Food Engineering Progress
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• v.14 no.3
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• pp.222-228
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• 2010

Effect of baking on the physicochemical and sensory properties was investigated using a model system of sponge cakes incorporated with Ecklonia cava powder as a value-added food ingredient. Ecklonia cava powder was incorporated into cake batter at 5 levels (0%, 2%, 4%, 6%, and 8%, w/w) by replacing equivalent amount of wheat flour. After appropriate mixing, sponge cakes were baked at ${185^{\circ}C}$ for 20 min in an oven. The baked cakes were cooled to room temperature for 1 hr prior to all measurements. The specific gravity of batter increased gradually with increase in Ecklonia cava powder content. The specific volume of sponge cakes tended to decrease while baking loss increased. Volume of the cakes decreased with higher amount of Ecklonia cava powder in the formulation as indicated by the decrease in the volume index. Sponge cakes became darker and firmer with increase in Ecklonia cava powder content (p<0.05). Color, seaweeds smell, and taste were distinctively classified by the sensory analyses (p<0.05). Finally, correlation analysis indicated that level of Ecklonia cava powder incorporation was well-correlated with all the physicochemical and sensory properties studied except for $a^{*}$-value and sensory firmness (p<0.05, p<0.01 or p<0.001).