• Journal of Korean Society of Environmental Engineers
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• v.37 no.10
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• pp.583-589
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• 2015

This study was performed to evaluate the feasibility of anaerobic pretreatment for the leachate solubilized from thermal hydrolysis of sewage sludge cake. Overall process for the treatment of sludge cake consists of thermal hydrolysis, crystallization of magnesium, ammonium, and phosphate (MAP) for the leachate and anaerobic digestion of supernatant from MAP crystallization. The experimental evidence showed that the optimum ratio of Mg : P for the struvite crystallization of leachate solubilized from thermal hydrolysis of sludge cake was 1.5 to 1.0 as weight basis at the pH of 9.5. With this operational condition, the removal efficiencies of ammonia nitrogen and phosphorous achieved 50% and 97%, respectively. The mesophilic batch test showed that the ultimate biodegradability of the supernatant from MAP crystallization reached 63% at S/I ratio of 0.5. The readily biodegradable fraction of 90% ($S_1$) of the MAP supernatant BVS (Biodegradable Volatile Solids, $S_0$) degraded with $k_1$ of $0.207day^{-1}$ for the initial 17 days where as the rest slowly biodegradable fraction ($S_2$) of 10% of BVS degraded with $k_2$ of $0.02day^{-1}$ for the rest of the operational period. Semi-Continuously Fed and Mixed Reactor (SCFMR) was chosen as one of the best candidates to treat the MAP supernatant because of its total solids content over 6%. Maximum average biogas production rates reached 0.45 v/v-d and TVS removal efficiency of 37~41% was achieved at an hydraulic retention time (HRT) of 20 days and its corresponding organic loading rate (OLR) of 1.43 g VS/L-d.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.57-62
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• 2008

The application of constructed subsurface-flow wetlands for treatment of wastewater from abandoned mines is being increased. Crushed limestone, oak chips, and mushroom composites are often employed in a bulk form, as the substrates in the bed media. Efficiency of the subsurface-flow treatment system drops with time as the hydraulic conductivity of the wetland soil decreases significantly, presumably due to chemical reactions with the wastewater. The purpose of this study is to investigate the applicability of immobilized beads carrying sulfate reducing bacteria for acid mine drainage treatment system. The ingredients of immobilized beads are organic materials such as mushroom composite and oak chips, limestone powder for a pH buffer, mixed with a modified Coleville Synthetic Brine. It was found that immobilized beads are more efficient than the bulk form for pH recovery, sulfate and heavy metal removal.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.704-711
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• 1994

Lipoxygenase of mackerel gill exhibited the highest reactivity toward eicosapentaenoic acid (EPA) followed by arachidonic acid, linoleic acid. The optimum pH were pH 4.5, 5.0 and 4.8 for EPA, arachidonic acid and linoleic acid, respectively. The enzyme was the most stable at pH 5.5. Optimum temperature was $25^{\circ}C$ for all substrate fatty acids. For linoleic and arachidonic acids the highest thermal stability was observed at $8^{\circ}C$ whereas, for (EPA) at $20^{\circ}C$. Optimum ionic strength was 0.22M, $Sn^{2+}$, vitamin E and catechin completely inhibited the enzyme at the concentration of 1.0mM. Molecular weight of the enzyme was 42,000 dalton.

• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.95-104
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• 2020

In this paper, we propose the real time indoor air quality monitoring and controlling platform on cloud using IoT sensor data such as PM10, PM2.5, CO2, VOCs, temperature, and humidity which has direct or indirect impact to indoor air quality. The system is connected to air ventilator to manage and optimize the indoor air quality. The proposed system has three main parts; First, IoT data collection service to measure, and collect indoor air quality in real time from IoT sensor network, Second, Big data processing pipeline to process and store the collected data on cloud platform and Finally, Big data analysis and visualization service to give real time insight of indoor air quality on mobile and web application. For the implication of the proposed system, IoT sensor kits are installed on three different public day care center where the indoor pollution can cause serious impact to the health and education of growing kids. Analyzed results are visualized on mobile and web application. The impact of ventilation system to indoor air quality is tested statistically and the result shows the proper optimization of indoor air quality.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.21-27
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• 2022

Air purifiers can be placed where the air cleaning is required, making it easy to manage indoor air quality. The position of the air purifier affects the indoor airflow pattern, resulting in different air cleaning efficiency. Many efforts and strategies have been examined through numerical simulations and experiments to find the proper location of the air purifier, but problems still remain due to the various geometrical indoor spaces and arrangements. Herein, we develop an artificial intelligence model to predict the performance of an air purifier depending on the installation location. To obtain the training data, numerical simulations were performed on the different locations of the air purifiers and airflow patterns. The trained artificial intelligence model predicted the air exchange performance depending on the installation location of the air purifier with a prediction accuracy of 92%.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.10a
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• pp.244.2-244
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• 1979

고분자 기질을 분해하는 효소의 고정화 후의 활성 yield을 높히고자 Polysaccharide의 표면에 acrylamide 및 N-hydroxysuccinimidyl acrylate을 graft 공중합 시킴으로써 긴 측쇄에 활성 ester을 가지는 새로운 carrier에 phosphiesterase을 고정화 시켰으며 이 고정화된 phosphodiesterase의 몇가지 성질을 조사하여 본래의 phosphiesterase의 성질과 비교하였다. 1) 이 Carrier에 phosphodiesterase을 직접 고정화시킨 결과 52%가 고정화되었으며 고정화된 효소는 38%의 비활성을 나타내 주었다. 2) phosphodiesterase는 이상과 같이 고정화됨으로써 최적작용 pH는 8.0부근에서 9.0부근으로 최적작용온도는 $50^{\circ}C부근에서$ $60^{\circ}C부근으로$ KM치는 1.11mg에서 2.1mg/ml로 변하였으며 열안정성은 훨씬 증가하여 본래의 phosphodiesterase의 열불활성속도상수가 0.4인데 고정화된 효소는 0.03 이었다. 또 $5^{\circ}C에서$ 수용액상태(pH 8.0 Tris buffer)로 6개월 보관후의 관존 활성은 본래의 효소가 0.2%인데 고정화된 효소는 42%로 높은 치를 나타내주었다.

• Journal of Life Science
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• v.8 no.6
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• pp.627-637
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• 1998

In order to utilize tuna pyloric caeca among fish intestines wasted when treated raw fish in fish processing manufactory, a crude enzyme with high proteolytic activity was extracted and its optimum condition were investigated. An immobilized enzymes also were prepared by adsorption method to enhance thermostability of the crude proteinase. The yield of the crude proteinase was approximately 2.7% on dry basis. The proteolytic activity for casein was 0.54 U/mg protein, for BTEE 1.10 U/mg protein, and for BAEE 2.69 U/mg protein. It was almost similar to that of the commercial trypsin purified. Optimum hydrolysis activity of the crude proteinase was about 80%, as the degree of hydrolysis for casein, at pH 10.0 and 45$^{\circ}C$ for 12 hrs. Also, when the crude proteinase was immobilized on DEAE-Cellulose and chitin, the residual activities remained after 7 days of pre-incubation time were maintained about 90% or more and their thermostabilities were enhanced by about 50%, compared with the native enzyme.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.208-215
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• 2005

This study was accomplished in order to collect fundamental data on microbial roles in recycling process of reed rhizosphere. Sunchon bay, which is considered as one of the marsh and mud environments severely affected by human activities such agriculture and fisheries, was selected as a model place. In our initial efforts, two bacterial consortia were obtained by enrichment culture using PAH mixtures containing anthracene, naphthalene, phenanthrene and pyrene as the sources of carbon and energy, and four pure bacteria capable of rapid degradation of PAH were isolated from them. Four strains designated as SCB1, SCB2, SCB6, and SCB7 revealed by morphological, physiological and molecular analyses were identified as Burkholderia anthina, Alcaligenes sp., Achromobacter xylosoxidans., and Pseudomonas putida, respectively with over $99{\%}$ confidence. Notably, Burkholderia anthina SCB1 and Alcaligenes sp. SCB2 were found to utilize anthracene and pyrene more quickly than naphthalene and phenanthrene, whereas Achromobacter xylosoxidans SCB6 and Pseudomonas putida SCB7 exhibited similar growth and degradation patterns except for pyrene. These facts suggest that the rhizosphere microorganisms capable of PAH degradation might be used to clean up the contamination sites with polycyclic aromatic hydrocarbons.

• Journal of environmental and Sanitary engineering
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• v.19 no.4 s.54
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• pp.76-81
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• 2004

From September 1, 2003 to November 30, 2004, 20 mineral water wells were selected for some area in east Europe and the study on their water quality was analized. It revealed that mineral water contained considerable quantity of magnesium ions which helps the smooth activities of vascular muscles, nervous systems and protects skins from allergic reactions. It also lowers cholesterol level and contains high concentration of calcium ions which is one of the vital components of teeth and bone like phosphorus. Thus it is concluded that it is not qualified as boiler feed water as it has overall high degree of hardness by the presence of four times content of $Mg^{2+}\;and\;Ca^{2+}$.

• Journal of Life Science
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• v.24 no.6
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• pp.694-699
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• 2014

Indigenous microorganisms play decisive roles in biodegradation. In this study, eighty strains of hydrocarbon-degrading microbes were isolated from Incheon Bay. Among them, 12 strains were selected by an oil film collapsing method. The bacterial strain 'Incheon9' was eventually selected based on its relatively higher lipase and emulsification activities, and was identified as Acinetobacter sp. (NCBI accession code: KF54854). The optimum condition for the growth and emulsification activity of Acinetobacter sp. Incheon9 was $20^{\circ}C$, pH 7, and 1% NaCl. The optimum time for the best production of biosurfactant was 72 hrs. The oil degradation ability of Acinetobacter sp. Incheon9 was investigated by measuring the residual oils in the culture medium by gas chromatography (FID). This research provides foundational data for eco-friendly environmental remediation by microorganisms.