• Journal of agriculture & life science
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• v.45 no.2
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• pp.21-28
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• 2011

Hibiscus cannabinus L is a plant in the Malvaceae family. Kenaf was seeded at June 1st in 2010 and harvested at November 18th and dried and evaluated worth as a bulking agent for livestock composting. Harvested and dried Kenaf was divided into the bast, core and leaf. All materials were grinded by hammer mill and the moisture absorption, moisture evaporation, pH, volume weight and C/N ratio were measured. Kenaf was higher water absorption and evaporation ability than those of sawdust and chaff. The pH values of Kenaf were pH $2.8{\pm}0.01$ - $4.34{\pm}0.02$, which is lower pH value than those of sawdust (pH $5.28{\pm}0.01$) and chaff (pH $6.3{\pm}0.02$). The C/N ratio of Kenaf showed 649 of core, 204 of bast and 70 of leaf, which were lower than sawdust (789.1) but higher than chaff (132). In volume weight test, the materials were divided by particle size of Kenaf, named as group A(${\geq}4cm$), B(${\leq}4cm$, ${\geq}0.25cm$) and C(${\leq}0.25cm$). The volume of weight of group A and B for core, bast and leaf showed similar, but group C showed higher than those of sawdust and chaff. Especially, the volume weight of group C for leaf was 5 times higher than those of sawdust and chaff. This study suggested the possibility of using Kenaf as a bulk agent for composting of livestock manure. This is considered that strengthen the competitiveness of farmers through reducing the cost, prevention of environmental pollution caused by livestock manure and environmentally friendly processing of livestock manure.

• Journal of Korean society of Dental Hygiene
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• v.13 no.2
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• pp.351-360
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• 2013

Objectives : The purpose of this study was to evaluate the effects of tooth bleaching agent contained 15% carbamide peroxide on the color, microhardness and surface roughness of tooth-colored restorative materials by using pH cycling model. Methods : Four types of tooth-colored restorative materials, including a composite resin(Filtek Z350 ; Z350), a flowable composite resin(Filtek P60 : P60), a compomer(Dyract$^{(R)}$ AP ; DY), and a glass-ionomer cement(KetacTM Molar Easymix ; KM). were used in the study. Eighty-eight specimens of each material were fabricated, randomly divided into two groups(n=44): experimental group(15% carbamide peroxide) and control group(distilled water). These groups were then divided into four subgroups(n=11). All groups were bleached 4 hours per day for 14 days using pH cycling model. The authors measured the color, microhardness, and roughness of the specimens before and after bleaching. The data were analyzed with ANOVA and T-test. Results : Z350 and P60 showed a slight color change(${\Delta}E^*$), whereas DY and KM showed significantly color change(p<0.05). Among them, the greatest color change was observed in DY. Percentage microhardness loss(PML) of the distilled water group was 1.8 to 5.1%, and 15% peroxide peroxide group was 5.0 to 25.2%. Microhardness of DY and KM showed a statistically significant decrease(p<0.05). Roughness was increased in all groups after bleaching. Z350 and P60 does not have a significant difference(p>0.05), however DY and KM significantly increased more than the 0.2 ${\mu}m$(p<0.05). Conclusions : The effects of bleaching on restorative materials were material dependent. It is necessary to consider the type of the material before starting the treatment.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.263-268
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• 1995

A screening was performed to isolate exoploysaccharide-producing microorganisms, which synthesized specific exopolysaccharide for the substitutive of commercial polysaccharides, from natural sources. Soil bacterium, one of 378 mucoid isolates, was finally selected as potential producer of polysaccharides which made the culture broth very viscous and thus examined in detail for optimal medium composition. Isolated strain was identified as Xanthomonas sp. EPS- 1 from the results of morphological and biochemical characteristics. The composition of optimal medium for exopolysaccharide production was as follows: 50 g sucrose, 1.5 g peptone, 2 g KH$_{2}$PO$_{4}$, 2 g MgSO$_{4}$, -7H$_{2}$O, 3 g NaCl, 0.05 g CaCO$_{3}$, 0.07 g FeSO$_{4}$-7H$_{2}$O and 0.05 g MnSO$_{4}$-7H$_{2}$O in 1 liter of distilled water. From the experiments of temperature and pH dependence, the optimal conditions for exopolysaccharide biosynthesis seemed to be 30$\circ$C and 8.0, respectively. About 14.9 gram of maximum exopolysaccharide per liter was obtained at the initial pH 8.0, 30$\circ$C and 250 rpm in a flask culture. The exopolysaccharide EPS-1 had such potential as an emulsifying agent and a gelling agent in comparision with commercial exopolysaccharide.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.4
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• pp.499-509
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• 1999

This study was carried out to investigate the effects of wearing disposable diaper with the endothermic agent on thermoregulatory response of infant. Five healthy female infants aged about 5 months were taken as a subject of this experiment. Experimental diapers were six kinds of disposable diaper constructed of nonwoven tissue, fluff pulp, super absorbent polymer, back sheet film, leg elastic, and 0g urea(A) 1g urea(B) , 2g urea(C), 3g urea (D), 4g urea(E) 5g, urea(F) respectively. Urea(98% or over purity) was used as an endothermic agent. Experiment was proceeded while infants were sleeping at 27.5$\pm$0.5$^{\circ}C$, 50$\pm$5% R.H, 0.04m/sec. Each disposable diaper's properties was tested. During the experiment rectal temperature skin temperature of 9 areas temperature inside the disposable diapers were measured, the results were as follows : 1) There was not significant difference among the diapers in absorption capacity retention capacity and rewet(p=0.05). The absorption under load was showed to A, B,

• Journal of Pharmaceutical Investigation
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• v.27 no.1
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• pp.23-27
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• 1997

To investigate the effect of L-arginine as stabilizing agent for omeprazole, the degradation rate constant of omeprazole in aqueous solution was determined at 30, 40 and $50^{\circ}C$ with various ratios of L-arginine to omeprazole. The pH of omeprazole solutions was also determined. As the amount of L-arginine increased, the pH of omeprazole solution also increased, and the solution appeared to be more stable. The omeprazole in aqueous solution could be stabilized by more than 15:1 molar ratio of L-arginine to omeprazole. The stability of omeprazole in commercial products using L-arginine or sodium phosphate dibasic as stabilizing agent was investigated. Among the commercial products, the omeprazole product prepared with L-arginine (molar ratio of L-arginine to omeprazole, 20:1) was most stable.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.210-211
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• 2017

According to KS F 2560, water-reducing agents used when mixing concrete are to undergo quality evaluation testing slump, air contents, setting time, etc., when delivered from the admixture factory to the ready mixed concrete site. Yet in actual acceptance testing this could be substituted by the score report of the admixture company, in which a possibility of low reliability lies. Therefore this study sought to analyze whether by artificially changing the solid content rate of lignin- and naphthalene-based water-reducing agents and using a liquid densimeter evaluate the quality of the admixture. The results showed that the Type B liquid densimeter was most appropriate and 50cc the most appropriate capacity for the mass cylinder. Also, judging from the changes in density and pH according to the changes in solid content rate, it concludes that a rapid appraisal of the quality of lignin- and naphthalene-based water-reducing agents would be possible using a Type B liquid densimeter.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.66-72
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• 2015

This study was conducted to investigate the effects of optical brightening agents (OBA) on the chemical degradation characteristics of paper cellulose during humid heating aging. Three different types of OBAs were applied to a filter paper by dipping it in OBA solutions whose concentrations were controlled to 1% and 2%. The filter papers with an OBA were artificially aged at $80^{\circ}C$ and 65% RH, and the changes in pH of paper and viscosity of cellulose were evaluated. Their functional groups were also analyzed by ATR-FTIR (at-tenuated total reflectance fourier transform infrared spectroscopy). It was found that OBAs influenced the chemical degradation of paper cellulose during humid heating aging. Higher concentration of OBA solutions accelerated the degradation of paper cellulose. Especially, after aging for 12 days, the paper cellulose treated with the tetra-type OBA were the most significantly aged among the three types of OBAs. It was assumed that pH of OBA solutions affected the aging characteristics.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.92-99
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• 2014

The pH sensitive hydrogels composed of N-isopropylacrylamide (NIPA) and acryloyl phenylalanine (APA) were prepared by redox polymerization using N,N'-methylenebisacrylamide (MBA) as a crosslinker. Anti-inflammatory and analgesic agent, Keterolac Tromethamine (KT), was loaded successfully into poly(NIPA-co-APA) copolymeric hydrogels by swelling equilibrium method. To understand the nature of drug in the polymeric matrix, the newly synthesized drug loaded poly(NIPA-co-APA) copolymeric hydrogels were characterized by using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. The scanning electron microscopy (SEM) technique result indicates the spherical smooth surface of the hydrogels. The drug (KT) releasing nature of the poly(NIPA-co-APA) hydrogels was studied in pH 1.2 and 7.4. Effects of drug loading, crosslinking agent, pH and the ionic strength of the external medium on swelling of hydrogels were also investigated.

• Advances in nano research
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• v.7 no.3
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• pp.169-180
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• 2019

Plasmonic effects of gold and platinum alloy nanoparticles (Au-Pt NPs) and their comparison to size was studied. Various factors including ratios of gold and platinum salt, temperature, pH and time of addition of reducing agent were studied for their effect on particle size. The size of gold and platinum alloy nanoparticles increases with increasing concentration of Pt NPs. Temperature dependent synthesis of gold and platinum alloy nanoparticles shows decrease in size at higher temperature while at lower temperature agglomeration occurs. For pH dependent synthesis of Au-Pt nanoparticles, size was found to be increased by increase in pH from 4 to 10. Increasing the time of addition of reducing agent for synthesis of pure and gold-platinum alloy nanoparticles shows gradual increase in size as well as increase in heterogeneity of nanoparticles. The size and elemental analysis of Au-Pt nanoparticles were characterized by UV-Vis spectroscopy, XRD, SEM and EDX techniques.

• Journal of odor and indoor environment
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• v.17 no.4
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• pp.381-388
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• 2018

In this study, various conditions and phenomena that occur in the process of removing odorous VOCs by using electrolyzed oxidant were examined. The formation of hypochlorous acid, which is an oxidant produced by electrolysis, was investigated and the properties of the oxidizing agent used to decompose toluene, xylene, and cyclohexane were investigated. As a result, it was found that the production rate and the final concentration of the oxidizing agent increased with the current density. It was found that the degree of removal varies depending on the property of each pollutant. Interestingly, in the batch experiments in which the pH of the produced oxidant was controlled, it was found that the degree of elimination varied depending on the pH of the substance. These results suggest that the difference in the concentration and distribution of hypochlorous acid (HOCl) and hypochlorite ($OCl^-$) due to the pH change leads to the difference in oxidizing power on the oxidation characteristics of each substance. Styrene and terpineol showed better degradation characteristics than toluene and xylene in odorous VOC removal experiments by spraying electrolytic oxidant using a lab-scale continuous reactor. In conclusion, the removal of odorous VOCs by the electrolytic oxidant can have various applications in that it can oxidize pollutants of various spectra.