• Ocean Science Journal
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• v.41 no.4
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• pp.221-226
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• 2006

More attention has been paid to the research on decolorization of dyeing wastewater nowadays. In this study, an investigation into the decolorization of dyeing wastewater was conducted using a combination of coagulant, carboxymethyl chitosan (NOCC) and coagulant aid, polyscrylamide (PAM). The factors influencing the decolorization efficiency, such as pH value, coagulant and the dosages of coagulant, were discussed. The results showed that using PAM as coagulant aid could reach a high decolorization efficiency compared with using NOCC alone. The optimal conditions were pH 2.3, 480 mg/L for NOCC, and 4-8 mg/L for PAM. Under the optimum conditions, the rate of decolorization could achieve 99%, and the removal of chemical oxygen demand (COD) could achieve 90%. In addition, the membrane processes with chitosan/rare-earth-metals could enhance the decolorization rate of Direct Black FF to 94.7%, and Indanthren Red F3B to 98.2%, respectively.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.11a
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• pp.147-156
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• 2005

In developing the ubiquitous computing technology based services (ubiquitous services), evaluating how much value of those services is created or added is very crucial. The efforts to evaluate the ubiquitous services have been progressed in two perspectives - technical perspective and behavioral perspective. Despite its importance, however, the methodologies which integrate both perspectives have been still very rare. Hence, this paper aims perspectives have been still very rare. Hence, this paper aims to propose an integrated ubiquitous service valuation methodology based on the multi-layered approach including technical and behavioral perspectives. To do so, we conducted a case study with currently existing location based service (LBS) such as navigation systems by conducting focus group interview (FGI) and field survey.

• Communications for Statistical Applications and Methods
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• v.31 no.1
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• pp.65-85
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• 2024

The tail probability of a function of a multivariate random variable is not easy to estimate by the crude Monte Carlo simulation. When the occurrence of the function value over a threshold is rare, the accurate estimation of the corresponding probability requires a huge number of samples. When the explicit form of the cumulative distribution function of each component of the variable is known, the inverse transform likelihood ratio method is directly applicable scheme to estimate the tail probability efficiently. The method is a type of the importance sampling and its efficiency depends on the selection of the importance sampling distribution. When the cumulative distribution of the multivariate random variable is represented by a copula and its marginal distributions, we develop an iterative algorithm to find the optimal importance sampling distribution, and show the convergence of the algorithm. The performance of the proposed scheme is compared with the crude Monte Carlo simulation numerically.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1127-1137
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• 2000

Applications of lanthanum ion and crude rare earth chloride to the phosphate wastewater and fluorine wastewater, respectively, as treatment agents were studied. For the investigation of phosphate removal characteristics according to the amount of lanthanum ion, initial phosphate content was decreased by about 50% when molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] was 0.25 and nearly all of phosphate was removed when the molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] to be doubled. The removal of phosphate by $La^{3+}$ appeared to reach equilibrium state rapidly, and it was exothermic reaction since the removed amount of phosphate was diminished somewhat when the reaction temperature was increased. The zeta potential of combined particulate compound of lanthanum ion and phosphate was located for its isoelectric point at pH 5.5 and the turbidity of treated wastewater was found to vary according to the pH in a similar manner as the absolute value of zeta potential of the combined particulate compound did. For the treatment of fluorine wastewater by crude rare earth chloride, the remaining fluorine content after treatment decreased as the dosage of crude rare earth chloride increased. Whereas, the turbidity of treated wastewater and the amount of sludge generated were shown to increase as more crude rare earth chloride was added. The remaining fluorine content and the turbidity of treated wastewater were decreased and the amount of sludge generated was observed to increase according the increase of coagulant dosage under the condition of constant input of crude rare earth chloride.

• Journal of The Geomorphological Association of Korea
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• v.23 no.2
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• pp.15-27
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• 2016

Since restoration of damaged geomorphological sites is almost impossible, it is necessary, to select and conserve geomorphological heritages in a preemptive action. Algific (=producing cold) sites are one of the natural resources which have not been protected well due to the lack of understanding of their value, despite their conservation importance. This research aimed to help people to recognize such geosites' actual value and make them understand the necessity of protecting these sites. Algific areas are valuable by the simple fact that it is a mysterious phenomenon in which the ice forming may happen even in the mid-summer and the environment is always cool. Algific sites deserve geomorphological research in the sense that topographic condition called talus causes this phenomenon. They are also valuable in plant geographic sense because northern rare plants survive isolatedly due to low-temperature environment of these sites. Their cultural-historical value is also high by the fact that they have been connected closely with local residents' lives shown by its nicknames, "natural refrigerator" or "natural air conditioner".

• Food Science of Animal Resources
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• v.32 no.4
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• pp.414-427
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• 2012

Carcass characteristics and meat quality traits as a function of endpoint months of slaughter age (26 vs 32 mon) and chiller ageing (1 vs 10 d) were evaluated for m. longissmus of 26 Hanwoo steers fed with commercial diets including whole crop barley silage. Totally twenty six Hanwoo steers for 6 mon of age that were fed until 26 mon of age constituted the short term-fed group and fed until 32 mon of age constituted long-term fed group. Carcasses were chilled for 24 h and were graded. Strip loin samples were divided into two age groups (1 d and 10 d). Long-term feeding increased carcass weight, rib-eye area, yield grade, marbling score, firmness and quality grade of the meat. The feeding for 32 mon produced tender, juicy meat (p<0.01) with lower cooking loss and higher rating score (p<0.05) than short term feeding, while other quality traits were not influenced by the length of feeding. Intramuscular fat content and oxidative stability (TBARS value) were significantly (p<0.05) higher in beef from long-term feeding however the length of feeding did not alter the fatty acid composition. Chiller aging reduced instrumental tenderness (WBSF value), improved color, sensory tenderness, acceptability and rating of beef. The results of the present study mirrors that Hanwoo steers until 32 mon of age overall improved carcass traits and palatability compared to that for 26 mon. However, from the viewpoints of economical and environmental aspects, cost of the additional feeding for 6 mon for value-adding of eating quality was relatively high and the effects in turn were limited.

• Particle and aerosol research
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• v.12 no.2
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• pp.37-42
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• 2016

$CeO_2$ nanoparticles were prepared by a flame spray pyrolysis from aqueous solution of cerium nitrate. The morphology, structure crystallinity and specific surface area of as-prepared nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brunauer-Emmett-Telle (BET). The $CeO_2$ nanoparticles about 5 nm in diameter showed a cubic fluorite structure and polyhedral morphology. The average particle size increased as the cerium nitrate concentration increased. UV absorption performance of the as-prepared nanoparticles was measured by UV-visible spectroscopy. UV absorption of $CeO_2$ nanoparticles was more effective than that of commercial $TiO_2$ nanoparticles. Effect of dopants such as Ti and Zn to $CeO_2$ nanoparticles on UV absorption properties was also investigated. In case of $Ti/CeO_2$, and $Zn/CeO_2$ nanoparticles, they showed a little higher UV absorption values compared with $CeO_2$ nanoparticles. The as-prepared nanoparticles can be promising materials with high UV absorption value.

• Advances in environmental research
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• v.5 no.2
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• pp.125-140
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• 2016

The paper is focused on the economic analysis of two hydrometallurgical processes for recovery of yttrium and other rare earth elements (REEs) from fluorescent phosphors of spent lamps. The first process includes leaching with sulphuric acid and precipitation of a mixture of oxalates by oxalic acid, the second one includes leaching with sulphuric acid, solvent extraction with D2EHPA, stripping by acid and recovery of yttrium and traces of other rare earths (REs) by precipitation with oxalic acid. In both cases the REEs were recovered as oxides by calcination of the oxalate salts. The economic analysis was estimated considering the real capacity of the HydroWEEE mobile's plant ($420kg\;batch^{-1}$). For the first flow-sheet the cost of recycling comes to $4.0{\euro}kg^{-1}$, while the revenue from the end-product is around $5.40{\euro}kg^{-1}$. The second process is not profitable, as well as the first one, taking into account the composition of the final oxides: the cost of recycling comes to $5.2{\euro}kg^{-1}$, while the revenue from the end-product is around $3.56{\euro}kg^{-1}$. The process becomes profitable if the final RE oxide mixture is sold for nearly $50{\euro}kg^{-1}$, a value rather far from the current market prices but not so unlikely since could be achieved in the incoming years, considering the significant fluctuations of the Res' market.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.485-498
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• 2008

This study was conducted to evaluate effects of dietary rare earth on growth performance, blood immune- related cell population, meat quality and fecal odor emitting gases in finishing pigs. The total of sixty four (Landrace×Yorkshire×Duroc) pigs(65.42±1.16kg in average initial body weight) were used for feeding trial during 10 weeks of experimental period. Dietary treatments included 1) NC(antibiotic free diet), 2) PC (NC diet+6 weeks 44ppm of tylosin/ 4 weeks 22ppm of tylosin) 3) RE1 (NC diet + 100ppm of RE), 4) RE2 (NC diet+200ppm of RE). There were four dietary treatments with four replicate pens per treatment and four pigs per pen. During the overall periods, there were no significant differences in ADG(Average daily gain), ADFI (Average daily feed intake) and gain/feed ratio among treatments(P>0.05). Dry matter and nitrogen digestibility were higher in RE2 treatment group than other groups(P<0.05). Also, energy digestibility was higher in RE2 treatment group than PC and RE1 treatment groups(P<0.05). At the 6th week WBC(white blood cell) was significantly increased(P<0.05) in RE1 treatment group than NC and RE2 treatment groups. L* value of M. logissimus dorsi muscle color was significantly increased(P<0.05) in rare earth supplemented groups compared to NC treatment group(P<0.05). However, a* value was lower in RE1 treatment group than PC treatment group (P<0.05). In fatty acid composition of Intramuscular fat, total MUFA was significantly higher in RE2 treatment group than other groups(P<0.05). Also, total UFA was significantly increased in RE2 treatment group compared with NC and PC treatment groups(P<0.05). In fatty acid composition of back fats, total SFA of rare earth supplemented groups were lower than in PC treatment group(P<0.05). UFA:SFA ratio was significantly higher in rare earth supplemented groups than PC treatment group(P<0.05). In fecal odor emission, NH3 was significantly decreased(P<0.05) in rare earth supplemented groups compared to NC and PC treatment groups. In conclusion, the results of the experiment was affected by rare earth supplementation on digestibilities, meat quality, fatty acid and fecal odor emission gases in finishing pigs.

• Journal of Korean Society of Forest Science
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• v.107 no.2
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• pp.113-125
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• 2018

Subalpine zone is geographically vulnerable to climate change. Forest vegetation in this zone is one of the important basic indicator to observe the influence of climate change. This study was conducting phytosociological community classification and endemic-rare plants investigation based on vulnerable species to climate change at the subalpine zone, Mt. Jiri. Vegetation data were collected by 37 quadrate plots from March to October, 2015. In order to understand the species composition of plant sociological vegetation types and the ecological impacts of species, we analyzed the layer structure of vegetation type using important values. Vegetation type was classified into eight species groups and five vegetation units. The vegetation types can be suggested as an indicator on the change of species composition according to the future climate change. There were 9 taxa endemic plants and 17 taxa rare plants designated by KFS(Korea Forest Service) where 41.2% of them were the northern plant. Endemic-rare plants increased as the altitude of vegetation unit increase. Importance value analysis showed that the mean importance value of Abies koreana was highest of all vegetation units. Based on analysis of each layer, all units except vegetation unit 1 were considered to be in competition with the species such as Quercus mongolica and Acer pseudosieboldianum. The results of this study can be a basic data to understand the new patterns caused by climate change. In addition, it can be a basic indicator of long-term monitoring through vegetation science approach.