• Tunnel and Underground Space
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• v.25 no.5
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• pp.435-449
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• 2015

Physical and microstructural properties of Pungchon and Maggol limestone were investigated quantitatively during 50 cycles of artificial freezing and thawing test. There were decrease in dry weight and P,S-wave velocity, and increase in absorption rate in both rock types. Porosity, pore volume, equivalent diameter, throat thickness and pore orientation were analyzed using X-ray computed tomography images. Porosity increased, and initiation and expansion of pores were investigated as weathering progresses. Physical and microstructural variation in Maggol limestone was larger than that of Pungchon limestone because Maggol limestone has more pores and microcracks at initial state. As this study analyzes physical and microstructural properties of rock specimens comprehensively, it can be applied to further rock weathering study and can be used as fundamental data of construction and resource development in cold regions.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.1
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• pp.55-62
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• 2016

As interest in health has recently increased, many researchers have investigated the utilization of functional foods by confectioneries and bakeries. However, research on loaf bread containing beets has not been conducted. To investigate the optimal ratio of beet in loaf bread containing beet powder, characteristics of loaf bread according to 2%(B2), 4%(B4), and 6%(B6) beet powder per wheat flour were examined. The experimental results were as follows. Fermentation rate was reduced as content of beet powder increased compared with the control, whereas pH levels of dough and loaf bread significantly increased as content of beet powder increased. As content of beet powder increased, volume of loaf bread decreased, whereas specific volume increased. There was no significant difference in volume of loaf bread between the samples. As far as color changes are concerned, as content of beet powder increased, L value decreased, whereas a and b values increased with significant differences between the samples. Characteristics were examined by sensory evaluation of loaf bread containing beet powder. Color of inner texture and peel color of loaf bread significantly increased as content of beet powder increased. Size of air pores was largest in B4, and there was no significant difference in the uniformity of loaf bread between the control and experiment groups. As content of beet powder increased, rigidity of bread was reduced. Control showed the highest elasticity, whereas moisture level was highest in B2 with no significant differences between the samples. The flavor of beet was stronger as content of beet powder increased. In the preference test, B4 showed the highest preference scores for texture, flavor, taste, and overall likeness but not appearance. The experimental results showed that B4 among all control and experimental groups had the most suitable baking characteristics and an optimum content of beet powder. Therefore, B4 can be considered as the most appropriate for making loaf bread containing 4% beet powder in terms of physical and sensory characteristics. This is a new product that satisfies overall sensory preferences and has improved functionality.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.4
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• pp.635-640
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• 2009

In this study, muffins were made with the addition of 0%, 3%, 6% and 9% of Chungkukjang powder and, the quality characteristics, such as volume, height, appearance, chromaticity and moisture contents, were measured using SEM (Scanning Electronic Microscope) measurement, texture tests and sensory tests. In the regards to volume, as the added amount of added Chungkukjang increased, the volume also increased. There was no significant difference in the height and moisture content of the muffins at the different Chungkukjang powder concentrations. Using SEM, it was shown that as the amount of added Chungkukjang increased, the gluten content decreased, which in turn caused the formation of thick cell membranes and rough pores and reduced gluten composition capacity. Luminosity L value in Chungkukjang muffin decreased as the amount of added Chungkukjang powder increased. There was significant difference in the red chromaticity a value and yellow chromaticity b value among the samples (p<0.05). The results of the texture test showed that the hardness of the Chungkukjang muffin decreased as the amount of added Chungkukjang increased. In addition, as the amount of added Chungkukjang increased, the adhesiveness decreased. There was no significant difference in springing, chewiness and gumminess among the samples. There was a significant difference in the cohesiveness among all other samples in cohesiveness (p<0.05). The results of the sensory test showed that the wave form of the Chungkukjang muffin decreased as the amount of added Chungkukjang increased. The pore of the muffin increased as the amount of added Chungkukjang increased. The color quality of the muffin decreased as the amount of added Chungkukjang increased. In terms of overall acceptability, 6% Chungkukjang was shown to result in the highest preference level.

• Journal of the Korean Society of Food Culture
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• v.33 no.6
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• pp.588-596
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• 2018

In this study, dry-milled rice flour from different varieties (Samgwang, Boranchan, Hanareum, Dasan, Hangaru) and different particle sizes were used to manufacture Jeung-pyun and the quality characteristics were analyzed. The Jeung-pyun produced from Samgwang, Dasan and Hangaru milled rice flour showed highly dense pores. The Jeung-pyun produced from Hanareum only showed a significant difference according to the particle size. Samgwang, Boranchan and Dasan varieties with a particle size of 150 m showed a significant decrease in volume (p<0.05). Samgwang showed the lowest pH at all particle sizes (p<0.05). The sweetness of Samgwang varieties was the highest at $3.27-3.63^{\circ}Brix$ (p<0.05). The hardness of Jeung-pyun increased with increasing particle size (p<0.05). The highest acceptance of Jeung-pyun in terms of volume and bitter taste was observed with Hanareum at a particle size of 50 m. When the particle size was 50 m, the overall acceptance was highest for Jeung-pyun made from Samgwang followed by Hanareum. The acceptance of all the sensory characteristics was high when the particle size of rice flour was 50 m. When the appearance of Jeung-pyun was measured, Samgwang showed a dense structure and low hardness. Hanareum showed an increasing volume and springiness. Overall Samgwang and Hanareum were found to be the most suitable varieties for the production of Jeung-pyun.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.259-264
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• 2002

In this study, sintering properties of Artificial Lightweight aggregates(ALAs) prepared from coal ash as a function of sintering temperature (900$^{\circ}$C, 1000$^{\circ}$C, 1100$^{\circ}$C) and time (2min, 5min, 10min) when limestone added as lightweight mineral was investigated. Increasing the sintering temperature resulted simultaneously from a decline of quartz mineral as well as growth of mullite mineral. Addition of limestone to ALAs newly formed sintered minerals such as clinoptilolite and plagioclase. Sintering effect of ALAs prepared from coal ash and limestone was more affected by a sintering temperature than time. As sintering temperature and time increae, transition of macropore to micropore and formation of closed pores were happened, consequently shrank the total pore volume of ALAs. The surface of ALAs sintered at 1000$^{\circ}$C for 5min was nearly not detected open pores due toe amalgamation effect of molten slag layer but homogeneous distributions of closed pores with micro-scale were examined in cross sectional area ALAs. Sintering temperature and time which present the most adequate state, in the preparation of ALAs, are corresponded to 1000$^{\circ}$C and 5min, respectively.

• Food Science and Preservation
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• v.30 no.4
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• pp.630-641
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• 2023

The quality characteristics of muffins with different types of rice flour, such as soft flour (CON), soft rice flour (SRF), floury rice flour (FRF), and rice flour (RF) were assessed by using Image J program, which includes their particle size analysis, moisture content, pH, color, specific volume, baking loss rate, texture. (D[4, 3]) is weighted mean diameter, which is directly obtained in particle size measurements showed large values in the order of rice flour, floury rice flour, soft rice flour, and soft flour. The moisture content was high in the CON and SRF groups with small particle sizes. There was no significant difference in pH, L and b value. The a value was significantly low only in the RF group with large particle size. The smaller the particle size, the higher the specific volume and baking loss rate. Image J showed that the number of pores decreased when fewer smaller particles were the powder, but the pores were larger. Among the rice flours, the SRF group, excluding the CON group, scored high in all the acceptability elements. The results from this study can be used as basic data that can contribute to research on various rice-processed foods.

• Earthquakes and Structures
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• v.15 no.4
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• pp.369-382
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• 2018

A free vibration analysis and wave propagation of functionally graded porous beams has been presented in this work using a high order hyperbolic shear deformation theory. Unlike other conventional shear deformation theories, a new displacement field that introduces indeterminate integral variables has been used to minimize the number of unknowns. The constituent materials of the beam are assumed gradually variable along the direction of height according to a simple power law distribution in terms of the volume fractions of the constituents. The variation of the pores in the direction of the thickness influences the mechanical properties. It is therefore necessary to predict the effect of porosity on vibratory behavior and wave velocity of FG beams in this study. A new function of the porosity factor has been developed. Hamilton's principle is used for the development of wave propagation equations in the functionally graded beam. The analytical dispersion relationship of the FG beam is obtained by solving an eigenvalue problem. Illustrative numerical examples are given to show the effects of volume fraction distributions, beam height, wave number, and porosity on free vibration and wave propagation in a functionally graded beam.

• Journal of Pharmaceutical Investigation
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• v.26 no.4
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• pp.281-289
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• 1996

In our previous work, we have studied the effect of lactose and sodium alginate (SA) on the rate of release of 5-fluorouracil (5-FU) from ethylene-vinyl acetate (EVA) matrix. These hydrophilic additives promoted the rate of 5-FU release and the increase in rate was larger when SA was used. Both additives showed better ability to increase the rate than 5-FU itself. In this paper, we extended our study to another hydrophilic additive, Carbopol 940 (CP). Compared to SA or lactose, CP increased the rate of 5-FU release markedly. Release rate increased as the loading amount and the pH of the release medium increased. After release experiment, matrix volume increased up to 15 times of that before release experiment, depending on the amount of CP dispersed in the matrix and the pH of the release medium. On the other hand, the volume of the matrix containing lactose or SA decreased. The weight changes of the dry matrix before and after release experiment imply that CP is not released out of the matrix, to the contrary of lactose and SA. Scanning electron microscope study clearly showed that large cavities and pores are generated on the surface and the inside of the matrix. These results indicate that the mechanism by which CP increases the release rate is quite different from that of monomeric additives such as lactose or SA.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.414-423
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• 2006

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925, Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower and the motion of grout is also a function of formation permeability. Viscosity of grout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this thesis, characteristics of new cement grout material that is developed recently is studied: injectable volume of new grout material is tested in two different sizes of sands, and the method to calculate injectable volume of grout is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to be an exponential function of time. And lumped parameter $\theta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressure.

• Computers and Concrete
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• v.1 no.4
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• pp.389-400
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• 2004

The examinations carried out have confirmed a relationship existing between the character of fracture surfaces and the composition and structure of (basalt and gravel) concretes. For both concretes investigated, a very good correlation was obtained between the profile line development factor, $R_L$, and the fracture surface development factor, $R_S$. With the increase in the $R_L$ parameter, the fracture surface development factor $R_S$ also increased. Agreement between the proposed relationship of $R_S=f(R_L)$ and the proposal given by Coster and Chermant (1983) was obtained. Stereological examinations carried out along with fractographic examinations made it possible to obtain a statistical model for the determination of $R_L$ (or $R_S$) based on the volume of air voids in concrete, $V_{air}$, the specific surface of air pores, $S_V_{air}$ the specific surface of coarse aggregate, $S_{Vagg.}$, and the volume of mortar, $V_m$. An effect of coarse aggregate type on the obtained values of the profile line development factor, $R_L$, as well as on the relationship $R_S=f(R_L)$ was observed. The increment in the fracture surface development factor $R_S$ with increasing $R_L$ parameter was larger in basalt concretes than in gravel concretes, which was a consequence of the level of complexity of fractures formed, resulting chiefly from the shape of coarse aggregate grains.