• Culinary science and hospitality research
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• v.18 no.3
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• pp.227-238
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• 2012

This study was carried out to evaluate the effect of ${\beta}$-glucan on rheological properties of flour dough and quality characteristics of white pan bread. Flour dough and white pan bread fortified with ${\beta}$-glucans at levels of 0%, 3%, 6% and 9% w/w. Farinograph and amylograph were analysed for the rheological properties. Loaf volume and specific loaf volume, moisture content, texture and sensory evaluation were also analysed for the quality characteristics. In the farinograph test, water absorption and dough development time of doughs increased with increasing ${\beta}$-glucan content. Especially, water absorption of dough fortified with 9% of ${\beta}$-glucan showed 13% higher than the control. However, the addition of ${\beta}$-glucan to the dough decreased stability. There were no significant differences on gelatinization temperature and maximum viscosity temperature regardless of ${\beta}$-glucan contents, but maximum viscosity increased with increasing ${\beta}$-glucan contents. Loaf volume and specific loaf volume of white pan bread decreased slightly with increasing ${\beta}$-glucan contents. Moisture content showed higher value in tests than that of the control, and the one added with 6% revealed highest moisture content. In terms of texture analysis, the one added with 6% of ${\beta}$-glucan revealed softer than the others. There were no differences between the groups added with 3% and with 6% on sensory evaluation, but the one added with 9% obtained lowest scores. As a result of this study, 6% of ${\beta}$-glucan is considered the resonable level to prepare healthy white pan bread. ${\beta}$-glucan can also be used when making cake and cookies.

• The Journal of Engineering Geology
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• v.34 no.1
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• pp.137-146
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• 2024

The pertinent Korean Industrial Standard (KS F) requires that rocks dried at 105 ± 5℃ be taken out of the oven into air and weighed on a scale. However, when rocks are exposed to air after the drying process, they absorb moisture, meaning that their weight will increase. In this study, eight cubic samples of Hwangdeung granite of different sizes were used to measure and compare the dry weight. The dry singularity weight measured in air was smaller than that measured in the drying oven. The difference in dry weight showed a positive correlation with sample size. Conversely, the difference in dry weight per unit weight of rock showed a negative correlation with sample size. The weight of a rock sample exposed to air is determined by the magnitude of the influence of convection currents occurring around the heated rock and the influence of moisture absorption in air. A singularity occurs when the magnitudes of these two effects are equal. The larger the rock sample, the longer the time taken for the singularity to occur, the greater the weight loss of the sample, and the longer the time taken for the sample to return to the initially measured weight on account of the greater moisture absorption for larger samples than smaller samples. In the future, research into the singularity and dry weights measured inside the drying oven will help to identify and address the limitations of the current KS F testing regulations.

• Journal of Korean Dental Science
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• v.16 no.1
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• pp.74-79
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• 2023

Purpose: Cention N (Ivoclar Vivadent) was a recently introduced alkasite-based restorative material that was expected to replace amalgam and glass ionomer cement. This material was an esthetic restoration with adequate mechanical strength and release of fluoride and calcium. The purpose of this study was to measure the water sorption and water solubility of Cention N and evaluate its long-term durability compared to other esthetic restorations (Resin-Modified Glass Ionomer cement [RMGIC], Giomer, Composite Resin). Materials and Methods: Twenty specimens each of Cention N (CN), Resin Modified-Glass Ionomer Cement (FJ), Giomer (BF), and Composite Resin (FZ) were made. After each specimen was completely dried in a desiccator for 24 hours using a vacuum pressure pump, the specimen was weighed (m1). After that, the specimen was immersed in distilled water at 37℃ for 7 days, stored in a drying oven, and weighed (m2). After drying completely for 24 hours in a desiccator, the specimen was weighed (m3) to calculate the water absorption and water solubility using Formulas 1 and 2. The measured values were statistically processed and analyzed using SPSS, and the significance level was set at 0.05. Result: When measuring water sorption, FJ (122.61 ㎍/mm³) showed significantly higher water sorption than CN (35.42 ㎍/mm³) (P<0.05). There was no significant difference between FZ (18.03 ㎍/mm³) and BF (14.76 ㎍/mm³) (P=0.930). When measuring water solubility, CN (6.65 ㎍/mm³) showed significantly higher water solubility than FJ (1.47 ㎍/mm³) (P<0.05). Conclusion: Cention N had lower water sorption than RMGIC, but higher water solubility, indicating that it is more vulnerable to moisture and has lessened long-term durability.

• Elastomers and Composites
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• v.55 no.1
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• pp.51-58
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• 2020

In this study, the thermal oxidation of raw natural rubber (NR) was investigated under controlled conditions by optical image and fourier transform infrared (FT-IR) analysis. The thermal oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at 80℃ under low humidity conditions to completely exclude moisture and restrict light oxidation. Images of the thin film of raw NR were obtained before and after thermal oxidation. FT-IR absorption spectra were measured in the transmission mode at different thermal exposure times. The thermal oxidation of NR was examined by the changes in the absorption peaks at 3449, 1736, 1447, 1377, 1242, 1072, and 833 cm^-1, which corresponded to a hydroxyl group (-OH), a carbonyl group (-C=O) from an aldehyde and a ketone, a methylene group (-CH₂-), a methyl group (-CH₃), a carbon-oxygen single bond (-C-O) from an epoxide, a carbon-oxygen bond (-C-O) from an ether, an alcohol, a peroxide, or a cyclic peroxide, and a cis-methine group (cis-CCH₃=CH-), respectively. In the initial stage of thermal oxidation, two different types of free radicals were produced quickly and randomly by the homolytic cleavage of a double bond and allylic hydrogen abstraction. Aldehydes and ketones were formed from chain scissions of the double bonds and alcohols were produced from allylic hydrogen abstraction at the methylene or methyl groups. Two reactions seemed to proceed competitively with each other. At a later stage, oxidative crosslinks seemed to dominate through the combination of free radicals such as an allyl radical (CH=CHCH₂·), alkoxy radical (RO·), and peroxy radical (ROO·) and the reaction of a hydroperoxide (-ROOH) with a double bond. The image obtained after thermal oxidation showed hardening without cracks. Based on these observations, a plausible two-step mechanism was suggested for chain hardening caused by the thermal oxidation.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.31-33
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• 2008

The study related that Red Phosphorus is surface coated by Al(OH)$_3$ using the proportion 1:1, 1:3, 1:5 respectively, and then take the coated red phosphorus as the core material, at the same time, use Melamine-Formaldehyde resin as the capsule materials for microcapsule processing. According to the TG analysis, the coated red phosphorus with the proportion 1:3 has the tiptop temperature of thermal decomposition, it reaches 376.20^{\circ}C$$. The same to the ratio of burning incomplete carbon it reaches 26.5%. The lowest moisture absorption ratio of the red phosphorus that used coated red phosphorus for microcapsule processing can reach 0.5% with the condition that thermal decomposition temperature decline 3.6%.

• Geotechnical Engineering
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• v.2 no.1
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• pp.7-14
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• 1986

The structure of the collapsible soils, such as decomposed granite soil and loess, were examined by the odeometer test, SEM & XES analysis and static & cyclic triaxial test, and hove this structure have influences upon the collapsible behaviour under static and cyclic load was investigated. The study results obtained are as follows; 1. The macropores space of decomposed granite soil (rd=1.50g/cm3) and loess (rd=1.43g/cm3) used in this test were well developed, and showed the behaviour of collapsible soil. 2. Collapsible soil has high resistance on the strain under natural moisture content, however, the resistance on the strain was sharply decreased by the absorption and increasing load since its special structure was destructed. 3. Under the static load, the strain of collapsible soil was high by the viscous flow of the cyclic bonds with time lapse, but Infer the cyclic load, the strain of collapsible soil was low since the tinge needed to destruct the bonding force of clay was not enough. 4. The understanding about the cyclic behaviour of collapsible soil may be helpful to predict the elastic & residual strain of the foundations by the earthquake together with the damage by the additional failure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.182-183
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• 2019

In this study, the optimization of mixing proportion of press-forming board with blast furnace slag, pearlite and bottom ash was investigated using the response surface methodology. Ten Mixing proportions of specimens were designed by the response surface design, and then flexural failure load, moisture content and water absorption of specimens were measured. As a result of the reaction surface analysis based on the experimental results, it was possible to derive the optimal mixing proportion with the satisfaction of 93%.

• Advances in concrete construction
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• v.4 no.4
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• pp.243-261
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• 2016

This research study focuses on utilizing sandstone which is overburden waste rock in coal mines to use in concrete as a replacement of fine aggregate. Physical properties of sandstone like water absorption, moisture content, fineness modulus etc., were found to be similar to conventional fine aggregate. Scanning Electron Microscope (SEM) analysis was carried out for analysing elemental composition of sandstone. There was no sulphur content in sandstone which is a good sign to carry the replacement. Fine aggregate was replaced with sandstone at 25%, 50%, 75% and 100% by volume and moulds of concrete cubes and cylinders were prepared. Compressive strength of concrete cubes was tested after 3, 7 and 28 days and split tensile & flexural strength was determined after 28 days. The strength was found to be increasing marginally with increase in sandstone content. Fine aggregate that was replaced by 100% sandstone gave highest strength among all the replacements for the compressive, split tensile and flexural strengths. Though increase in strength was marginal, still sandstone can be an effective replacement for sand in order to save the natural resource and utilize the waste sandstone.

• Journal of the Korean Society of Combustion
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• v.18 no.4
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• pp.1-11
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• 2013

The oxy-fuel combustion is $CO_2$ capture technology that uses mixture of pure $O_2$ and recirculated exhaust as oxidizer. Currently some Oxy-fuel power plants demonstration project is underway in worldwide. Meanwhile research project for converting 125 MWe Young-Dong power plant to 100 MWe oxy-fuel power plants is progress. In this paper, 1 D process analytical approach was applied for conducting process design and operating parameters sensitivity analysis for oxy-fuel combustion of Young-Dong power plant. As a result, appropriate gas recirculation rates was 74.3% that in order to maintain normal rating superheater, reheater steam temperature and boiler heat transfer patterns. And boiler efficiency 85.0%, CPU inlet $CO_2$ mole concentration 71.34% was predicted for retrofitted boiler. The oxygen concentration in the secondary recycle gas is predicted as 27.1%. Meanwhile the oxygen concentration 22.4% and moisture concentration 5.3% predicted for primary recycle gas. As the primary and secondary gas recirculation increases, then heat absorption of the reheater is tends to increases whereas superheater side is decreased, and also the efficiency is tends to decrease, according to results of sensitivity analysis for operating parameters. In addition, the ambient air ingression have a tendency to lead to decline of efficiency for boiler as well as decline of $CO_2$ purity of CPU inlet.

• The Korean Journal of Food And Nutrition
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• v.35 no.1
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• pp.16-33
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• 2022

The quality characteristics and antioxidant activity of Tteokbokkidduk alone or supplemented with 3%, 6%, 9%, and 12% wheat bran powder were assessed, to increase use of the wheat bran by-product of wheat milling. The moisture content, pH, and starch elution of Tteokbokkidduk increased with increasing wheat bran powder, while the water absorption rate did not. The L color value decreased and the a and b values increased with increasing wheat bran powder. Scanning electron microscopy of Tteokbokkidduk prepared with 0% and 3% wheat bran powder revealed uniform pore size distribution. In terms of texture profile analysis, hardness and chewiness increased, while cohesiveness decreased with increased content of wheat bran powder. Acceptance was highest for samples with 6% wheat bran powder. Quantitative description analysis (QDA) revealed increased brownness, roughness, nutty, bitterness, astringency, savory character, and hardness, and decreased adhesiveness, springiness, and chewiness with increased wheat bran powder. Principal component analysis (PCA) revealed highest overall acceptance of samples prepared with 6% wheat bran powder, reflecting the relatively low values of detrimental sensory characteristics. Antioxidant activities of Tteokbokkidduk increased as wheat bran powder content increased. The addition of 6% wheat bran powder resulted in excellent Tteokbokki in terms of acceptance, quality, and antioxidant activity.