• Journal of Environmental Science International
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• v.8 no.2
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• pp.189-195
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• 1999

Determining factors and temporal & spatial characteristics of COD(Chemical Oxygen Demand) at the sea surface in Jinhae bay have been examined by using seasonal data, taken at twenty six stations over the whole bay during 1989~1994 by NERDA. The data have been analyzed in terms of long term means, anomalously large values. Jinhae bay is divided into three regions based on the time mean : mouth of Jinhae bay, inner sea of Masan bay, western sea of Jinhae bay called region 1,2 and 3, respectively. The horizontal distribution of the long term mean of COD at each station is similar to those of nitrogen and phosphorus. Characteristics of whole mean variation in the year shows high range of variation in region 2. It was appear to decreases every year in whole trend. Factors determining seasonal variation in whole COD mean are relative to salinity and nutrient, affected by precipitation in summer. Spatial variation shows high range of fluctuation in region 2 compare to other region. Factors determining of spatial variation of COD was appear to nutrient, affected by pollutant load of land area and bottom sediment. The long term mean of COD at each station is closely related with thats of nutrients. The correlation coefficient between COD and nitrogen, phosphate phosphorus was found to be high as 0.75, 0.78, respectively. Anomalously large COD was observed 14 times at 6 stations. These stations are located in inner sea of Masan bay(Region 2) and Songjeong bay(Region 1). The seasonal frequency of the observed anomalous COD is large in April, and other seasons are much the same.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1369-1382
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• 2007

To find proper water quality management strategy for oxygen consumption organic matters in Jinhae bay, the physical process and net supply/decomposition in terms of COD was estimated by three-dimensional eco-hydrodynamic modeling. The estimation results of physical process in terms of COD showed that transportation of COD was dominant in loading area from land to sea, while accumulation of COD was dominant in $middle{\sim}bottom$ level. In case of surface level, the net supply rate of COD was $0{\sim}60\;mg/m^2/day$. The net decomposition rate of COD was $0{\sim}-0.05\;mg/m^2/day$($-5{\sim}-10$ m, in depth) to 2 level, and $-0.05{\sim}-0.20\;mg/m^2/day(10m{\sim})$ to bottom level. These results indicate that the biological decomposition and physical accumulation of COD are occurred for the most part of Jinhae Bay bottom. The variation of net supply or net decomposition rate of COD as reducing land based input loading is also remarkable. Therefore, it is important to consider both allochthonous and autochthonous oxygen demanding organic matters to improve the water quality of Jinhae Bay.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.179-188
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• 2011

Steel structures have been allowed to have fatigue damage tolerance in fact. If it would be assessed whether fatigue crack is growing or not and How fast fatigue crack is propagating, we should make a rational decision on methods and a period of reinforcement in the maintenance. In this study, fatigue crack growth tests on two kinds of through-thickness cracked steel plates and a out-of-plane gusset welded joint were conducted to evaluate fatigue crack growth rate using the COD(Crack Opening Displacement), and COD measurement using strain gauges was examined to offer a practical method. As a result, we proposed a reasonable assessing method for fatigue crack growth rate using the COD and it was experimentally proved practical to estimate the COD through measuring strains.

• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.28-37
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• 2009

The diet of Pacific cod (Gadus macrocephalus) in the East Sea, Yellow Sea and Jinhae Bay was studied by analysis of stomach contents. In total, 518 individuals ranging from 15.5 to 77.0 cm standard length SL were analyzed. Prey organisms of the Pacific cod in the East Sea consistedof Caridea, Cephalopoda and Pisces, whereas In the Yellow Sea, the main food items of Pacific cod were similar to those of East Sea Pacific cod except for Cephalopoda. Interestingly, the stomach contents of Pacific cod in Jinhae Bay is mainly Pisces, which is in contrast to those of the two different coastal areas, the East Sea and the Yellow Sea. Although various species of food were eaten by smaller Pacific cod, both Caridea and Pisces were mainly taken by larger Pacific cod. Consequently, the diet of Pacific cod within acertain size is mainly influenced by prey abundance and prey-size spectrum in its habitat. Higher stomach emptiness of Pacific cod in Jinhae Bay might indicate that fully matured Pacific cod temporally stop feeding during their spawning period.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.139-146
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• 1998

The characteristics of color and COD removal for dyeing-wastewater using electrochemical reaction were investigated. >From the result, the removal efficiency of color and COD were increased with increase of temperature, decrease of electrode distance, increase of electrolyte concentration and increase of potential and these were obtained above 99%, above 75% within 30 min, individually. Cause of higher COD removal efficiency, it is more suitable that dyeing-wastewater is treated by electrolytic treatment prior to biological treatment. It is concluded that the electrolytic treatment of dyeing-wastewater can be used as the effective and economical method in practical treatment.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2047-2058
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• 2000

The effects of operating parameters on performance of upflow anaerobic sludge blanket(UASB). anaerobic filter(AF), and two-stage anaerobic sludge bed filter (ASBF) bioreactors in treating swine wastewater were evaluated by operating the lab-scale bioreactors upto hydraulic retention time(HRT) of 1 day and organic loading rate (OLR) of $5.1kg-COD/m^3{\cdot}d$ for 200 days. Swine wastewaters of which characteristics were affected by types of hog raising and seasons contained high concentrations of COD, SS, and ammonia. Inoculation of the bioreactors with waste sludge from anaerobic treatment facility of local municipal wastewater treatment plant was effective in developing biomass in the bioreactors. Acclimation period of the bioreactors with swine wastewaters required approximately 40 days, but that for AF and two-stage ASBF, which were filled with media, was faster than VASB. The bioreactors showed high and stable COD removal efficiency of 77~91% at influent T-N concentrations of 370~800mg/L but low and unstable COD removal efficiency of 24~94% at influent T-N concentrations of 760~1,310mg/L. It is essential to remove ammonia prior to anaerobic treatment since the concentrations of ammonia in swine wastewaters showed toxic effects to methanogenic bacteria. The bioreactors were effective in treating swine wastewaters with COD removal efficiency of 78.9~81.5% and biogas generation rate of $0.39{\sim}0.59m^3/kg-COD_r$ at OLR of $1.1{\sim}2.2kg-COD/m^3{\cdot}d$: however, an increase of OLR by reducing HRT and increasing influent COD caused decrease of COD removal efficiency. The extent of decrease in COD removal efficiency was higher in UASB than AF and two-stage ASBF. AF and two-stage ASBF anaerobic bioreactors were effective in treating varing characteristics of swine wastewaters since they showed high and stable COD removal efficiency at high OLR due to effective retention of biomass by media and staging.

• Economic and Environmental Geology
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• v.35 no.1
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• pp.43-54
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• 2002

The Chonju and Samchun streams are palling though Chonju City and several contamination sources are located along these streams. The Samchun stream joins the Chonju stream in the Gosapyeong waste disposal site and the Chonju stream finally joint to the Mankyeong River. The Chonju and Samchun streams are now contaminated with BOD, COD, T-N and T-P and the amounts of each contamination are increasing from upper stream to downstream. At the downstream the amounts of COD. T-N.T-P are several times higher than fifth grade of water quality thor lacustrine. Sewage from Chonju provides BOD, COD,T-N and T-P into the Chonju and Samchun streams and Chonju Waste Water Treatment Plant il a main source of COD, T-N and T-P contamination. Gosapyeong waste disposal site may be the source of BOD and COD contamination. T-N is higher than fifth grade of water quality for lacustrine at the upper stream indicationg that the rivers are contaminated with T-N before inflowing into Chonju by agricultural activity. The Chonju stream asffects the contamination of the Mankyeong river with BOD. COD, T-N,T-P. Other branch steams of the Mankyeong river also affects the contamination of the Mankyeong river by BOD, COD, T-N and T-P, Among the branch streams, the Ikasn stream is a main contamination source. Amounts of concentrations inflowing from the Chonju and Sanchun Streams on Aug. 1999 are calculated by using yeasured flow rate find concentrations of contaminants The result are as fikkiws; 1) the amounts of influent from the Gosan Stream are 0.49, 0.86, 1.61 and 0.01 ton/day for BOD, COD, T-N and T-P, respectively, 2) compared to the amounts of influent from the Gosan Stream, BOD, COD,T-N,T-P supplied from the Chonju river are higher by about 5, 7, 7. 36 times, respectively, and those supplied from the Iksan stream are higher by about 13, 10, 10, 147 times, respectively.

• Imaging Science in Dentistry
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• v.37 no.4
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• pp.185-189
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• 2007

Purpose: This study was intended to estimate the prevalence of cemento-osseous dysplasia (COD) in the Korean population and to assess the clinical and radiographic characteristics of this condition. Materials and Methods: Panoramic radiographs from 10,646 patients (4,982 males and 5,664 females, age range from 6 to 91 years) were reviewed for evidence of COD. Their demographics, clinical characteristics, and radiographic features were retrospectively assessed. Results: Of 10,646 panoramic radiographs, 33 radiographs (0.31 %) exhibited evidence of COD. The prevalence of COD increased to over 1 % in women over 40-years old. Of these 33 patients, 16 had florid cemento-osseous dysplasia (FCOD) and 17 had focal COD. Due to the multiplicity of FCOD, a total of 63 COD lesions were assessed. These lesions were most common in the mandibular molar area. Most of the COD lesions examined (61.9%) were less than 10 mm and the majority (82.5%) showed radiopacity. Conclusion : COD has a predilection for the mandibular molar area of middle-aged and older women.

• Journal of Sensor Science and Technology
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• v.23 no.4
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• pp.272-277
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• 2014

At present, the index of chemical oxygen demand (COD) is widely used as an indicator of organic water pollution with biochemical oxygen demand (BOD). But, traditional COD measurement method are not only with various chemical reagents exhausted, but also long time consumed, the operation procedure and the modification are much professional. This paper reported a novel COD measurement system using double-beam and multiple wavelength analysis UV-VIS spectrometries. It consists of pulsed xenon lamp, two-way optical fiber, optical switch, spectrometer and main processor. Proposed COD measurement system obtains any spectral information of water sample (KHP standard sample and two river water and wastewater) and reference sample (distilled water) in the range of 200~520 nm, corresponding to the COD concentration from 0 to 300 mg/L through calculating the UV absorbance. The system show improved precision and can work continuously fast at time interval about 25 seconds.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.119-125
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• 2004

Sugar beet stillages were used as a substrate for the production of single cell protein by a thermotolerant yeast Candida rugosa. 3 Stillage substrates were nutritionally optimized for the better production of yeast biomass and for the reduction of COD. The addition of Phosphorus(P) was required for all stillages, but Nitrogen(N) only when the residual sugar remained. The addition of P increased the biomass production to 23-61%. The addition of N increased the biomass production only a little, but when added together with P increased to 90%. The COD decreased to 26-46% when P was added, but decreased to 85% when P was added together with N.