• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7754-7760
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• 2015

The outer tie rod is one of the part of steering system, the optimization process was executed to find the lightweight design. The inner tie rod was considered in the optimum design of an outer tie rod. it could be closer to the test condition than in the case of considering outer tie rod only. The aluminum forging material was considered as a weight reduction proposal. The target of optimization was the shape of the minimum weight to resist at the load of buckling. RSM and Kriging interpolation method were applied as a optimization method to consider the nonlinear shape optimization problem. Then, 16.3%, 16.6% of weight reduction was obtained from the result comparing with that of the initial model. The results of meta model optimization was compared with that of finite element method. The error values of buckling load estimation were 2.6%, 2.04%. and those of weight estimation were 0.17%, 0.13%. Therefore, it seemed that the result of Kriging model could be obtained closer to optimum value than that of RSM model.

• Applied Microscopy
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• v.30 no.1
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• pp.11-20
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• 2000

The morphological changes in normal and weathering hair shafts of the human scalp were investigated by using the transmission and scanning electron microscopes. The hair shaft composed of cuticular layer, cortex and medula. The surface of normal hairs are smooth and covered by imbricated cuticular scales. The cuticular layer consists of five to seven cuticle cells. These cells, which are flat and thin, measuring about $100{\mu}m$ long and $0.4{\mu}m$ thick, appears intercellular membrane complex in diameter 25 nm. The cortex composed of melanin granules and cornified cells, which multicomponent concentric microfibrils in diameter about 8 nm give rise to macrofibrils in diameter $0.5{\mu}m$ to $0.8{\mu}m$ encased in limiting membrane. The melanin granules are spherical shaped about $0.5{\mu}m$ in size and scattered between macrofibrils. The medulla in the normal hairs are $16{\mu}m$ in diameter centrally region of cortex. Normal hair shafts undergo progressive degenerative changes due to a variety of environmental insults. In the initial weathering process of hair, the cuticular scales became irregularly raised and broken, and then cuticle cells formed cytoplasmic vacuolation, following dissociated intercellular membrane complex, ultimately entirely lost and nuded cortex. Occasionally, transverse fissures were seen at hair shafts indicating that the hairs were deteriorated. Complete removal of the cuticular layer in the heavily damaged cortex portions appeared splitting of the cortical cell into its macrofibrils and scattering of melanin granules.

• Journal of Conservation Science
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• v.31 no.1
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• pp.1-11
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• 2015

Seated Amitabha Triad at Muwisa Temple (Treasure No. 1312) had been known as wooden Buddha statue, but a precise safety inspection revealed that the statue is terracotta Buddha statue made with clay. The clay layer of Amitabha Triad was conserved due to its severe damage. In this study, experiments were conducted to produce the most appropriate filler for the conservation treatment of the seated Amitabha Triad. Mixed clay samples with various ratios were produced and surface hardening state, crack, color change, and shrinkage of the samples during dry process were measured. Loess, fine sand powder, and cotton were used to produce the mixed clay for the filler with six different ratios and then 12 different concentration glues made with glutinous rice glue, Pachymeniopsis Elliptica glue, and animal glue were added as adhesives. Total 72 types of samples were prepared and comparative study was conducted. As a result, when the mixed clay contains 2.5% cotton compared to the weight per cent of loess and fine sand powder and also loess and fine sand in the mixed clay have a 15:1 ratio, the mixed clay had the lowest shrinkage. Animal glue is considered as an appropriate glue since it had small color change, low physical property change and shringkage. Therefore, mixed clay (loess:fine sand=15:1) mixed with 15ml animal glue is likely to be a suitable filler for conservation treatment of the seated amitabha triad at the Muwisa Temple.

• Korean Journal of Community Nutrition
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• v.14 no.6
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• pp.817-830
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• 2009

The purpose of this study was to analysis the sanitary management performance based on HACCP system for school foodservice. This study was carried out from September 2008 until December 2008 and is targeted towards schools' dietitians that work at schools with school foodservice. The regional distribution of this research is as follows; 377 schools in Seoul, 648 schools in Gyeonggido, 160 schools in Kangwondo, 438 schools in Choongchungdo equaling 1,623 schools in total. When school foodservices were put through sanitation management achievement level analysis applied by the HACCP system, results displayed that management of temperature (3.96 points), time (4.08 points), and cross-contamination (4.07 points) were all below the average achievement level. HACCP system's achievement level based on the TQM showed that areas for strategy development, leadership, information and analysis had low achievement levels. Achievement levels for CCP are quality check, delivery/distribution process, sterilization/cleansing of food's contact surface. As a result of multiple regression analysis of the factors that influenced sanitation management achievement level of school foodservice HACCP system; sanitary job standard showed 35.6% and CCP achievement levels showed 26.8% explanatory rate. In particular, Kangwondo's number of foodservice provided to per cook was small. Also, the better the processing management was assessed, the higher the sanitary job standard achievement level became resulting to a explanatory rate of 39.5%. Elementary schools showed a higher explanatory rate of 37.0% than middle and high schools. CCP achievement levels in middle and high schools with self-operated foodservice had a 28.0% variable explanatory rate, which was the highest. The better the drainage system, leadership and assessments turned out to be, the higher the CCP achievement levels became. In summary, to revitalize HACCP system that is based on the TQM, it is considered that proper database of HACCP system for school foodservice's sanitation management be constructed and more emphasis should be put on strategy development to improve customers' satisfactory level. In addition, improvements in achievement levels of time, temperature, and cross-contamination for sanitary job standard and CCP achievement level are essential.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1037-1044
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• 2000

The objective of this study is the preparation of activated carbon for BAC(biological activated carbon). Prepared activated carbon was measured iodine adsorption(mg/g). methylene blue adsorption(mg/g), B.E.T($m^2/g$), PSD(Pore Size Distribution) and 'Picabiol' which in commercial activated carbon for BAC. Activation method for this study was a chemical activation used the phosphoric acid. In the method, two important factors affected activation characterized in preparation were temperature and impregnated phosphoric acid concentration. Activation temperature and impregnated phosphoric acid concentration were changed the $600{\sim}800^{\circ}C$ and 35~50wt% respectively. Activation time was fixed for 3 hour. Optimal activation temperature was $800^{\circ}C$ and impregnated phosphoric acid concentrations was about 50wt%. By the above condition specific surface area, iodine adsorption number and methylene blue adsorption number resulted $1643.3m^2/g$, 1093 mg/g, 445.6 mg/g, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.195-203
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• 2012

In this study, The effects of three different biological activated carbon (BAC) materials (each coal, coconut and wood based activated carbons) and anthracite, empty bed contact time (EBCT) and water temperature on the removal of MK, HHCB and AHTN in BAC filters were investigated. Experiments were conducted at three water temperatures (5, 15 and $25^{\circ}C$) and four EBCTs (5, 10, 15 and 20 min). The results indicated that coal based BAC retained more attached bacterial biomass on the surface of the activated carbon than the other BAC, increasing EBCT or increasing water temperature increased the synthetic musk compounds (SMCs) removal in BAC columns. The kinetic analysis suggested a first-order reaction model for MK, HHCB and AHTN removal at various water temperatures (5, 15 and $25^{\circ}C$). The pseudo-first-order biodegradation rate constants and half-lives were also calculated for MK, HHCB and AHTN removal at 5, 15 and $25^{\circ}C$. The pseudo-first-order biodegradation rate constants and half-lives of MK, HHCB and AHTN ranging from 0.0082 $min^{-1}$ to 0.4452 $min^{-1}$ and from 1.56 min to 84.51 min could be used to assist water utilities in designing and operating BAC filters for SMCs removal.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.3
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• pp.186-192
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• 2009

In this study, The effects of three different activated carbon materials (each coal, coconut and wood based activated carbons), empty bed contact time (EBCT) and water temperature on the removal of pharmaceutical 4 species (oxytetracycline, tetracycline, trimethoprime and caffeine) in BAC filters were investigated. Experiments were conducted at three water temperature (5, 15 and $25^{\circ}C$) and four EBCTs (5, 10, 15 and 20 min). The results indicated that coal based BAC retained more attached bacterial biomass on the surface of the activated carbon than the other BAC, increasing EBCT or increasing water temperature increased the pharmaceutical 4 species removal in BAC columns. In the coal-based BAC columns, removal efficiencies of oxytetracycline and tetracycline were 87~100% and removal efficiencies of trimethoprime and caffeine were 72~99% for EBCT 5~20 min at $25^{\circ}C$. The kinetic analysis suggested a firstorder reaction model for pharmaceutical 4 species removal at various water temperatures (5~$25^{\circ}C$). The pseudo-first-order reaction rate constants and half-lives were also calculated for pharmaceutical 4 species removal at 5~$25^{\circ}C$. The reaction rate and half-lives of pharmaceutical 4 species ranging from 0.0360~0.3954 $min^{-1}$ and 1.75 to 19.25 min various water temperatures and EBCTs, could be used to assist water utilities in designing and operating BAC filters.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.427-434
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• 2009

Indigenous bacterium which shows a tolerance to high metal toxicity was isolated from soil concomitantly contaminated with oil and heavy metals. The characteristics of the bacterium for Pb and Cd biosorption was investigated under the various experimental conditions such as bacterial growth phase, the initial metal concentration, the input biomass amount, temperature and pH. The Langmuir adsorption isotherm modeling was described to know the capacity and intensity of biosorption. The low initial concentration of heavy metals and high biomass has a maximum heavy metal removal efficiency, but biosorption capacity of Pb and Cd has different values. Biosorption efficiency was highest in the end of the microbial growth stage and under pH 5~9 condition, but was less affected by temperature variation of 25~$35^{\circ}C$. The maximum biosorption capacity for Pb and Cd was 62.11 and 192.31 mg/g, respectively and each $R^2$ was calculated as 0.71 and 0.98 by applying Langmuir isothermal adsorption equation. Biosorption for Cd was considered as monomolecular adsorption to single layer on the surface of cells, whereas biosorption for Pb was considered as accumulation process into the cell by the microbial metabolism and precipitation reaction with anion of bacteria.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.243-274
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• 2013

To investigate the research state and characteristics of dinoflagellate cyst along the Korean coastal waters, this work analyzed 45 studies conducted in the Korean coasts and basin, the south of Jeju, East China Sea including some part of the Yellow Sea. It was found that the research on dinoflagellate cyst began in the later half of the 1980s in Korea, and that the research areas focused on eutrophied regions where a red tide occurred or on the seas where coastal development occurred. In other words, no research on the East Sea was found. In terms of research contents, there were various studies on analysis of cyst assemblage, tracking of the changes in marine environment like process of eutrophication, roles as a seed population in occurrence of a red tide, creation of cyst by use of sediment trip and tracking of its changes, morphological changes by the change of pH concentration in the hypoxia zone of eutrophied region, germination of a specific species, and other international-level studies. Species composition and cell density also varied in the Korean coastal waters. However, much research on dinoflagellate cyst in Korea is not systematic, and is fragmentary and individual and hencesuffers from great limitations. The research results so far have focused only on specific regions, and sporadic research had been conducted by specific research groups. Dinoflagellate cyst of surface sediments represents the accumulation index of pelagic environment in the sea and is a useful index to understand the marine environment efficiently. In conclusion, Korea requires organized human resources and collaborative research on dinoflagellate cyst which in turn should be considered as a component of marine ecosystem and as an essential aspect of marine biology.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.763-772
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• 2004

The patterns of fungal growth and fiber digestion under the microscope, and tile productions of fibrolytic enzyme were studied in an in vitro culture with Neocallimastix frontalis SA when either filter paper or rice straw was provided as sole energy source. Under the microscopic observation, active zoospores attachment, sporangium development and complex rhizoidal system were founded on the surface and at the edge of filter paper. After 7 days of incubation, a reduced fiber mass, a decreased fiber cohesion and a weakened fiber structure by fungal digestion were clearly observed. Similar fungal development was observed with rice straw, but fungal growth and digestion took place mostly on the damaged and exposed portion of rice straw. Although there were some differences in absolute concentration and pattern, the concentration of both cellulase and xylanase increased with incubation time with the higher activity being obtained with filter paper. Their differences were large especially after 48 and 96hr of incubation(P< 0.05). The filter paper was more good inducer of cellulolytic and xylanolytic enzymes compared with complex substrate, rice straw. These findings suggest that the filter paper is the better energy source for N frontalis than the complex substrate, and structural disintegration by physical process is able to help rumen fungal growth on the lignified roughage although anaerobic rumen fungi have mechanical and enzymatic functions for fiber digestion.