• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1775-1781
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• 2008

The effects of the type of curing agent on the swelling of the natural rubber(NR) sponge applicable to the self-sealing layer of a helicopter fuel tank were investigated. The curing systems employed were peroxide and mixed ones of sulfur and peroxide. The NR compounds were prepared in a kneader and a roll-mill. The compounds were partially cured in a press at high pressure and subsequently cured fully with expansion in another press at atmospheric pressure. The apparent density of the NR sponge was measured and the cell structure was observed with scanning electron microscopy. The swelling experiments were performed at room temperature using toluene, iso-octane, and an aircraft fuel as a solvent. More rapid volume swelling of the NR sponge cured by peroxide was achieved than cured by sulfur and peroxide with similar amount of curing agent added in rubber compounds. The apparent density and cell structure of the sponge were extremely sensitive to the amount of peroxide, which influences again the swelling behavior of the NR sponge. It is important to control properly two reactions of decomposition of foaming agent and crosslinking of NR in the mold to obtain rapid swelling of the NR sponge on contact of the fuel.

• Resources Recycling
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• v.21 no.6
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• pp.12-22
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• 2012

This study investigated a utilization technology of light burned dolomite. light burned dolomite ($CaMg(CO_3)_2$) generated in furnace (steel manufacturer) is an alternative to quick lime. Using light burned dolomite has an effect on reducing the consumption of fluorite slag MgO concentration in supersaturated solution by prolonging the life of softening effect. Armophous MgO, not containing periclase is formed by firing dolomite under $800^{\circ}C$. It has larger surface area and higher reactivity than periclase, and also shows better expansion effect than quicklime. Due to those effects, therefore, armophous MgO produced from light burned dolomite is used as an alternative expansion agent in mortar. In the experiment, characteristics of light burned dolomite were compared to those of existing expansion agents such as anhydrite and quicklime. Then, each expansion and shrinkage rates were measured over a period of about 3 months in both of 1m Jis mold at labscale and apartment mortar flooring at field scale. In the result, it was observed that light burned dolomite in mortar flooring more compensates for the expansion and shrinkage rates than the existing expansion agents, showing low expansion rate of below 0.05% and also decreases the crack.

• Applied Biological Chemistry
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• v.41 no.7
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• pp.539-544
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• 1998

A study was conducted to investigate the effects of Poria cocos powder on dough rheology and wet noodle quality. Poria cocos powder had considerably lower content of crude protein, crude fat and crude ash than those of wheat flour. Poria cocos powder had also much bigger particle size $(74.62\;{\mu}m)$ and larger surface area $(3884.13\;cm^2/g)$ than those of wheat flour. The peak, final viscosities and setback in amylograph increased with the increase of Poria cocos powder concentration. The water absorption and dough stability in farinograph increased with the increase of Poria cocos powder concentration. With the increase of Poria cocos powder, the L values decreased in wheat flour-Poria cocos powder blend and dough, but increased in wet noodles. The cooked weight and volume of cooked noodles decreased, but the turbidity of soup increased with the increase of Poria cocos powder concentration. The hardness, cohesiveness, chewiness and springiness of cooked noodles had the biggest values at 3% addition of Poria cocos powder, but the values decreased above that concentration. The sensory evaluation of cooked noodles showed that the wet noodles with high quality could be produced by $5{\sim}7%$ addition of Poria cocos powder.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.737-741
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• 2005

In this study, the effect of copper content on the NO removal efficiency by Cu/MCM-41 has been investigated. MCM-41 was prepared by hydrothermal synthesis using a gel mixture of colloidal silica solution and cetyltrimethylammonium. Cu/MCM-41 was manufactured with copper content (5, 10, 20, and 40%) in Cu(II) acetylacetonate. The surface properties of MCM-41 were investigated by using pH, XRD, and FT-IR analyses. $N_2/77K$ adsorption isotherm characteristics, including the specific surface area and micropore volume were studied by BET's equation and Boer's t-plot methods. NO removal efficiency was confirmed by gas chromatography technique. From the experimental results, the MCM-41 was analyzed to have the surface functional groups of Si-OH and Si-O-Si and the characteristic diffraction lines (100), (110), (200), and (210) corresponding to a hexagonal arrangement structure. The copper content supported on MCM-41 appeared to increase the NO removal efficiency in spite of decreasing the specific surface areas or micropore volumes. Consequently, it was found that the copper content in Cu/MCM-41 played an important role in improving the NO removal efficiency, which was mainly attributed to the catalytic reactions.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.179-186
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• 2020

In this study, chitosan/zeolite composites were prepared by using basalt-based zeolite impregnated with aqueous chitosan solution for the adsorptive separation of CO₂. The prepared composites were characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption analysis. In addition, the adsorption equilibrium isotherms for CO₂ and N₂ were measured at 298 K using a volumetric adsorption system, and the results were analyzed by applying adsorption isotherm equations (Langmuir, Freundlich, and Sips) and energy distribution function. It was found that CO₂ adsorption capacities were well correlated with the structural characteristics of chitosan and zeolite, and the ratio of elements [N/C, Al/(Si + Al)] formed on the surface of the composite. Moreover, the CO₂/N₂ adsorption selectivity was calculated under the mixture conditions of 15 V : 85 V, 50 V : 50 V, and 85 V : 15 V using the Langmuir equation and the ideal adsorption solution theory (IAST).

• Korean journal of food and cookery science
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• v.19 no.3
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• pp.354-362
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• 2003

higher. The Hunter color test showed lower L values with higher amounts of added JP to the Jeung-Pyun. In the sensory test. the 7 % added group had the strongest color according to the texture; the highest cohesiveness was shown in the 5 % added group, and the highest springiness was shown by the 3% added group, but none of these showed any significant differences. As for flavor, the more JP added the higher the stale grain flavor and bitterness. In the result of the overall acceptability test, the stale grain flavor of the 5% added group showed the highest values for the favorite texture and flavor. From the results of this experiment, when making stale grain flavored Jeung-Pyun, the 3 and 5% added groups were the optimum concentrations for the observed improvements in the quality. This study was carried out to investigate the possibility of improving the quality characteristics of Jeung-Pyun, by the addition of Paecilomyces japonica powder (JP). Regarding the volume of the Jeung-Pyun fermentation, with respect to the different amounts of JP added, the groups containing JP showed increased volumes, and as for the pH. the group containing 5% showed the lowest value. Regarding the moisture content, the groups containing JP showed lower moisture contents than the control group. Regarding the amino acid content, the control group showed a higher amino acid content than those of the JP containing groups, and contained an even amount of essential amino acids. and Leucine, Phenylalanine and Arginine were especially.

• Korean journal of food and cookery science
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• v.25 no.4
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• pp.467-473
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• 2009

The principal objective of this study was to assess the quality characteristics of Topokki with different amounts of curry powder[0%(CT0), 2%(CT2), 4%(CT4), 6%(CT6) and 8%(CT8)], based on the amount of rice flour. The L values of the uncooked and cooked Topokki decreased significantly with increases in the amount of added curry powder. The a and b values of cooked Topokki increased significantly with increases in the amount of added curry powder. The weight gains(%) of CT0(11.40%), CT2(11.67%) and CT4(10.93%) were significantly higher and the volume increases(%) of CT2(12.53%) and CT4(12.23%) were higher than those of the other samples. Textural properties such as hardness, cohesiveness, springiness and gumminess were also assessed. Our sensory evaluation test demonstrated that the appearance of CT2(4.24), the color of CT2(4.24) and CT4(4.26), the flavor of CT2(4.34) and the overall acceptability of CT2(4.24) and CT4(4.26) were superior to those of the others. CT4, CT6 and CT8 evidenced more profound antimicrobial activities than the others. In conclusion, the addition of $2{\sim}4%$ curry powder to the rice flour proved the most acceptable for the preparation of Topokki with curry powder.

• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.61-68
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• 2007

The purpose of this study was to compare the centering abilities of four root canal instrument systems and the amounts of dentin removed after root canal shaping using them. The mesial canals of twenty extracted mandibular first molars having $10-20^{\circ}$ curvature were scanned using X-ray micro-computed tomography (XMCT)-scanner before root canals were instrumented. They were divided into four groups (n = 10 per group). In Group 1, root canals were instrumented by the step-back technique with stainless steel K-Flexofile after coronal flaring. The remainders were instrumented by the crown-down technique with Profile (Group 2), ProTaper (Group 3) or K3 system (Group 4). All canals were prepared up to size 25 at the end-point of preparation and scanned again. Scanned images were processed to reconstruct three-dimensional images using three-dimensional image software and the changes of total canal volume were measured. Pre-and post-operative cross-sectional images of 1, 3, 5, and 7 mm from the apical foramen were com pared. For each level, centering ratio were calculated using Adobe Photoshop 6.0 and image software program. ProTaper and K3 systems have a tendency to remove more dentin than the other file systems. In all groups, the lowest value of centering ratio at 3 mm level was observed. And except at 3 mm level, ProTaper system made canals less centered than the other systems (p < 0.05).

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1066-1075
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• 2017

This study was carried out to determine the functional works and basic ingredients of Sagoonja-Tang on sponge cake. The experimental groups consisted of 6% mixtures of five (Ed-confirm the number) kinds powders : S1 for Sagoonja-Tang powder, S2 for Panax ginseng, S3 for Poria cocos, Koidz, S4 for Atractylodes macrocephala, and S5 for Glycyrrhiza uralensis Fisch. The volume of sponge cake somewhat decreased after adding the ingredients, and the volume differences in order from highest to lowest, were control>S1>S3>S2>S4>S5. In the microbiological quality test, viable cell counts were high in control groups of sponge cake, and the numbers of viable cell for control sponge cake reached to $9{\times}10^7CFU/g$ on the 7th day of storage, and decreased to $2.5{\times}10^5CFU/g$ on the 10th day of storage. All sponge cakes added with ingredient's powder showed pretty low viable cell counts. Especially, the group S5 showed the lowest counts of $1.2{\times}10^2CFU/g$ on the 7th day of storing. In the texture analyses of sponge cake, All groups showed higher degree of hardness, gumminess and chewiness than SC. The antioxidative activity of the Sagoonja-Tang's ingredients was measured. The POV value measured was S5>S4>S3>S2 >S1>control in order of highest to lowest. In sensory test, the overall acceptability of sponge cake was from highest to lowest S3>SC S2>S1>S5>S4.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.499-503
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• 2008

As the conference result of MEPC in IMO, development of ballast water management system corresponding to newly established ballast water management standard (D2 regulation) of shipping is being made an active progress over the whole world. The ballast water management system should treat particular material of more than $10{\mu}m$ in high capacity of more than 500t per hour in the event of filtration process. Also, it is very difficult to develop a practical management system since a limited element which a narrow space of the ship should be designed in the minimal volume is assumed. Therefore, the study promoted a study on the next generation auto back wash media filter to overcome such a limited element. Also, the study performed pressure and flux measurement test followed by thickness of each filter medium for filtration by each size to grasp a relation between absorption and pressure at the time of vacuum filtration and mechanical analysis and turbidity change observation of filtered water after vacuum filtration.