• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.42-45
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• 2008

It has been reported that FRP (fiber reinforced plastic) can be recycled by separating into layers instead of crushing into powder. F-fiber obtained from roving layer separated from FRP, has bigger tensile strength than the bundle of glass fibers of which FRP was made (more than 90%). SEM image of F-fiber shows the presence of some resin. Under the proposition of usage of F-fiber in the concrete material, tensile strength is examined after soaking in a basic solution (NaOH+KOH). The reaction mechanism of strength loss may be considered as an attack of hydroxide ion ($OH^-$) on a chemical bond of Si-O-Si of glass fiber. The simulation graph of the strength loss data implies certain reaction mechanism. While in the early stage kinetically controlled reaction results in a fast drop of tensile strength, after 30 days dispersion rate of hydroxide ion plays a major role in strength loss. This result is similar to the one for the AR glass. An extrapolation of the graph would make an assumption about the lift time of F-fiber possible.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.159-163
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• 2002

A single phase perovskite relaxor ferroelectric PMN-PT-BT was prepared by a single calcination and the modified mixed oxide process. It was accomplished by ball-milling PbO, $Nb_2O_5,\;Ti(OC_3H_7)_4,\;BaCO_3,\;and\;Mg(NO_3)_2$ instead of MgO, removing the solvent, and then followed by calcination at 900$^{\circ}C$ for 2h. The specimen sintered at 1100$^{\circ}C$/2h showed the sintered density of 7.83 g/$cm^3$, room temperature dielectric constant of 22000, and dielectric loss of 2.5%. Addition of 1.0 mole% (0.3 wt%) of Ag as $AgNO_3$ and followed by calcination at 550$^{\circ}C$/2h lowered the sintering temperature to 900$^{\circ}C$. It still showed the sintered density of 7.88 g/$cm^3$, room temperature dielectric constant of 20000 and dielectric loss of 2.4%.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.438-445
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• 2002

In this study, the glass frit of $PbO-TiO-2-SiO_2-BaO-ZnO-Al_2O-3-CaO-B_2O_3-Bi_2O_3-MgO$ system was manufactured. The glass was melted at $1,400{\circ}C$, quenched and attrition-milled. The glass frit powder was pressed and fired for 2h at the range of $750~1,000{\circ}C$. The crystallization of glass frit began at about $750{\circ}$ and at low temperature, the main crystal phases were hexagonal celsian($BaAl_2Si_2O_8$) and alumina. As the firing temperature increased, the crystal phases of monoclinic celsian, zinc aluminate, zinc silicate, calcium titanium silicate and titania appeared. And the increase of firing temperature led to transformation of hexagonal celsian to monoclinic. The only glass frit containing 15wt% PbO had the crystal phase of solid solution of $PbTiO_3-CaTiO_3$. At the frequency of 1 MHz, the dielectric constant of glass frit crystallized was in the range of 11~16 and the dielectric loss less than 0.020. But the glass frit containing 15wt% PbO had the dielectric constant of 17~26 and loss of 0.010~0.015 because of crystal phase of solid solution of $PbTiO_3-CaTiO_3$.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.71-83
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• 2014

This study carried out an experiment in order to compare thermal characteristics after collecting dust generated in the process of disposing of waste tire, plywood flour in the process of manufacturing plywood, salicylic acid dust in the process of manufacturing functional soap, and dust in the process of manufacturing wheat powder, which has potential fire and explosion hazard. According to the results of experiment, the analysis showed that all samples subject to the experiment were in the condition where heat flux decreased and temperature decreased as the quantity of added talc was increased. This shows that decomposition rate decreased, and hazard decreased. However, in all of samples subject to the experiment, as heating rate increased, endothermic onset temperature moved to the low-temperature part, and the amount of absorbed heat was largely increased. This showed that the decomposition hazard of sample increased as heating rate increased, according to the analysis. Besides, TGA experiment results showed that thermal stability was secured because total weight loss decreased as the amount of talc was increased for all samples subject to the experiment regarding the ratio of weight loss. It is expected that the continuous research and supplementation of dust explosion mechanism in the future will contribute to the establishment of measures for the effective dust explosion prevention.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.42-45
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• 2003

A Trichoderma sp. SO-571 producing cellulase was isolated from soil, and a pilot-scale cultivation and separation of cellulase were conducted. The cellulase activity was about 14.5 unit/ml after 112 hr of cultivation in a 301 fermenter containing 3.0% cellulose, 4.0% soybean powder, 3.0% wheat bran, 0.5% ($NH_4$)$_2$$SO_4$0.2% urea, 1.0% CSL, 0.5% $KH_2$PO$_4$, and 0.2% Tween 80. The cellulase was purified over 4.6 folds in three steps with 47.86% yield. The optimum pH of cellulase was pH 5.0 and optimum temperature was $60^{\circ}C$. To investigate the effect of the cellulase-treated cellulosic fabric, the weight loss was compared. The weight loss of denim treated with cellulase from Trichoderma sp.SO-571 was 2.9% and that with Celluclast 1.5L was 2.2%. In tencel treatement with enzyme, cellulase showed 0.7% higer weight loss than that with Celluclast 1.5L.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.1
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• pp.25-33
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• 2016

The study was performed to investigate the effects of whey protein-rich meal substitute added with vitamins, minerals, and lactobacillus powder probiotics on weight loss, body fat, and body composition in 24 female volunteers for 4 weeks. Whey protein-rich meal substitute was consumed with low-fat, high calcium milk (1% fat, 260 mg/200 mL) twice a day. Subjects submitted 3-day diet records and a life-style questionnaire before the study. During the study, subjects were required to turn in a diet record every day and consume the meal substitute formula in the metabolic ward at C university for 4 weeks. Anthropometric measurements were carried out weekly by Inbody 7.0. The dietary intake and anthropometric data were analyzed to compare changes before and after the study by paired t-test with SPSS version 23.0. The subjects were mostly early 20's and either overweight or obese and highly motivated to lose weight. Most of the subjects consumed three meals per day regularly and spent mostly 10~15 minutes for a meal. Their caloric intake was relatively low and decreased from 1,360 kcal at week 0 to 1,100 kcal after 4 weeks. However, total protein intake increased while carbohydrate and fat intakes decreased (p<0.05) after the trial. Nine vitamin intakes after the study improved compared to those before the study (p<0.05). After the study, subjects showed lower body weight (-1.8 kg), body fat (-0.94 kg), percent body fat (-0.86%), as well as waist circumference (-4.52 cm), hip circumference (-0.44 cm), waist hip ratio (-0.05), and triceps skinfold thickness (-2.39 mm) compared to those at week 0 (p<0.05). Muscle mass tended to be less compared to week 0, although there was no significant differences between weeks 0 and 4. In conclusion, diet trial with whey protein-rich meal substitute induced weight loss and positively changed body fat parameters and body composition.

• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.135-146
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• 1983

This study is to investigate the properties of domestic fly ash for utilization as data in regard to fly ash which is by-product of domestic coal powder plants and the possibility of utilization as insulation material of domestic fly ash. Composition refractoriness size distribution density contents of hollow particles and crystalline phase were examined as the properties of domestic fly ash. As to the fired test pieces of fly ash by itself that varied contents of hollow particles with four kinds and of the fly ash-clay-saw dust system linear shrinkage bulk density app. porosity compressive strength thermal conductivity and structures were investigated for the possibility of utilization as an insulation material. The results are as follows : 1. The properties of the fly ash I) The constituent particle of the fly ash is spherical and it contains not a few hollow particles (floats by water 0.30-0.50 floats by $ZnCl_2$ aq.(SpG=1.71) 6.97-16.72%). ii) The chemical compositions of fly ash are $SiO_243.9-54.1%$ , $Al_2O_321.0-30.7%$ Ig loss is 7.4-24.1% and the principal of Ig loss is unburned carbon. iii) Fly ash was not suitable to use for mortar and concrete mixture because Ig. loss value is higher than 5% 2. Utilization as insulation material I) The test pieces of original fly ash floats by water floats by ZnCl2 aq(SpG=1.71) p, p t by ZnCl2 aq.(SpG=1.71) that were fired at 110$0^{\circ}C$ represented 0.11-0.18 kcal/mh$^{\circ}$ C as thermal conductivity value. ii) The test pieces which (76.5-85.5) wt% fly ash-(8.5, 9.5) wt% clay-(5.0-15.0) wt% saw dust system(68.0-72.0) wt% fly ash -(17.0-18.0)wt% clay-(10.0-15.0) wt% saw dust system and 59.5 wt% fly ash-25.5 wt% clay-15.0wt% saw dust system were fired at 110$0^{\circ}C$ the thermal conductivity was less than 0.1Kcal/mh$^{\circ}$ C. iii) In view of thermal conductivity and economic aspect insulation materials which added saw dust as blowing agent and clay as inorganic binder are better than that of fly ash as it is or separated hollow fly ash particles. iv) When the saw dust contents increased in the (59.5-90.0) wt% saw dust system and when amount of clay de-creased and firing temperature decreased under the condition of equal addition of saw dust app. porosity increased but bulk density compressive strength and thermal conductivity decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.7
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• pp.914-920
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• 2008

In this study, hard roll breads were prepared with 3, 6, 9, 12, and 15% of concentrated sweet pumpkin powder (CSPP). The samples and a control were then compared in terms of quality characteristics, including pH, total titratable acidity, fermentation power of dough expansion, specific volume, baking loss, moisture content, color, textural characteristics, external and internal surface appearances, and sensory qualities of bread in order to determine the optimal ratio of CSPP in the formulation. As CSPP content increased, pH of dough, specific volume, baking loss, and lightness of bread decreased, while total titratable acidity of dough, pH, total titratable acidity, moisture content, and redness of bread increased. Fermentation power of dough expansion increased as incubation time increased. The CSPP samples had significantly higher yellowness, hardness, cohesiveness, gumminess, chewiness, and resilience than the control group. Adhesiveness was the highest at the 12% substitution level, while the lowest at the 6% level. Springiness increased with increasing CSPP content. In the sensory evaluation, as CSPP content increased, scores for color and consistency of crumb decreased, while scores for aroma of sweet pumpkin, sweetness, and delicious taste increased. Density of crumb pore were maximal with the 12% CSPP substitution. The CSPP samples had significantly higher uniformity of crumb pore and springiness of crumb than the control group. However, mouth-feel and overall acceptability showed the reverse effect, obtaining fairly good scores. In conclusion, the results indicate that substituting $6{\sim}9%$ CSPP to hard roll bread is optimal, providing good physiological properties as well as reasonably high overall acceptability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.1071-1076
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• 2016

The feasibility of incorporating aronia powder (AP) as a value-added food ingredient into convenient food products was investigated using cookie as a model system. AP was incorporated into cookies at amounts of 0, 1, 2, 3, and 4% (w/w) based on total weight of wheat flour. The pH level of cookie dough decreased significantly with increasing levels of AP (P<0.05), whereas moisture content and density were not directly affected by levels of AP incorporation. The spread ratio increased significantly upon addition of AP; however, it was not significantly affected by level of AP incorporation. The loss rate of cookies decreased significantly with increasing levels of AP (P<0.05). In terms of color, lightness and yellowness decreased while redness increased significantly (P<0.05) with increasing levels of AP. Use of AP significantly decreased hardness of cookies (P<0.05), but no significant differences were found between control and 1% sample, 1% and 2% sample, 2% and 3% sample, and 3% and 4% sample (P>0.05). 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities were significantly elevated by AP addition, and they increased significantly as AP concentration increased in the formulation (P<0.05). Correlation analysis indicated that acceptances of color and chewiness were negatively correlated well with the level of AP incorporation, density and moisture content of cookie dough, and cookie redness, whereas they were positively correlated with pH of cookie dough, loss rate, and hardness (P<0.01 or P<0.05). Finally, consumer acceptance test indicated that the highest levels of AP incorporation (4%) had an adverse effect on general consumer preferences. In contrast, cookies with moderate levels of AP (2%) are recommended based on overall scores to take advantage of the antioxidant properties of AP without sacrificing consumer acceptability.

• Journal of Life Science
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• v.23 no.3
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• pp.432-442
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• 2013

In this study, we examined the biological activity and synergistic effects of an extract powder of 1% and 3%, each fresh (FGP) and black garlic (BGP) in streptozotocin-induced diabetic rats. Blood glucose content was significantly lower in FGP and BGP groups than control group. Glycosylated Hb was significantly higher in streptozotocin induced diabetic control group than normal group, but significantly lower in FGP and BGP groups. Total cholesterol content of the FGP and BGP groups were lower than control group, but not shown the significant difference between garlic fed groups. HDL-cholesterol concentrations of the FGP and BGP fed groups were significantly higher than control group, except of 1% BGP group. LDL and VLDL-cholesterol contents were significantly lower in 3% FGP group, and the same tendency atherogenic index and cardiac risk factor. GOT, GPT, and ${\gamma}$-GTP activity of serum were lower in FGP and BGP fed groups than control group. Glycogen contents in liver significantly higher than control group, and has not significantly difference between normal group. TBARS content was no significantly difference in the liver and serum, but in the kidney, 3% FPG and BGP fed groups were significantly lower than other experimental group. DPPH radical scavenging activity of liver has not significant difference among experimental groups, but activity was higher garlic extract powder fed groups in serum and kidney. These results indicate that dietary supplements of fresh and black garlic extract powder was contributed to lower of blood glucose, loss prevention of glycogen in liver and improve of lipid metabolism.