• Journal of Energy Engineering
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• v.28 no.2
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• pp.18-35
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• 2019

The Korea District Heating Corporation operates a gas engine generator with a capacity of $4500m^3 /day$ of biogas generated from the sewage treatment plant of the Nanji Water Recycling Center and 1,500 kW. However, the actual operation experience of the biogas power plant is insufficient, and due to lack of accumulated technology and know-how, frequent breakdown and stoppage of the gas engine causes a lot of economic loss. Therefore, it is necessary to prepare technical fundamental measures for stable operation of the power plant In this study, a series of process problems of the gas engine plant using the biogas generated in the sewage treatment plant of the Nanji Water Recovery Center were identified and the optimization of the actual operation was made by minimizing the problems in each step. In order to purify the gas, which is the main cause of the failure stop, the conditions for establishing the quality standard of the adsorption capacity of the activated carbon were established through the analysis of the components and the adsorption test for the active carbon being used at present. In addition, the system was applied to actual operation by applying standards for replacement cycle of activated carbon to minimize impurities, strengthening measurement period of hydrogen sulfide, localization of activated carbon, and strengthening and improving the operation standards of the plant. As a result, the operating performance of gas engine # 1 was increased by 530% and the operation of the second engine was increased by 250%. In addition, improvement of vent line equipment has reduced work process and increased normal operation time and operation rate. In terms of economic efficiency, it also showed a sales increase of KRW 77,000 / year. By applying the strengthening and improvement measures of operating standards, it is possible to reduce the stoppage of the biogas plant, increase the utilization rate, It is judged to be an operational plan.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.65-71
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• 2024

The feather-sexing method is widely used commercially for chick sex identification. However, for feather-sexing to be industrially practical, the early-feathering (EF) and late-feathering (LF) genes must existed within the foundation stock, a suitable feather-sexing lines must be established, and the accuracy of sex identification by feather-sexing must be ensured. Therefore, this study introduces the method of constructing the Korean native chickens (KNC) feather-sexing lines using EF and LF genes and evaluates the effectiveness of feather sex determination on commercial chicks produced from the constructed KNC lines. The results showed that both EF and LF chickens existed within the foundation stock, with the frequency of LF genes ranging from 0 to 0.205. In feather-sexing line establishment, the paternal strain of the grandparent stock (GPS) was fixed as EF (kk) for both sexes, while the maternal strain was composed of males with LF homozygotes (Z^KZ^K) and females with EF (Z^kW). Thus, in the parent stock (PS), male breeder had EF (Z^kZ^k) and female breeder had LF (Z^KW), resulting in chicks produced from their crosses having LF (Z^KZ^k) for males and EF (Z^kW) for females, allowing sex determination based on feather development. Additionally, to evaluate the effectiveness of feather-sexing for the produced commercial chicks, a study was conducted on 1,000 samples of the produced chicks to investigate the concordance between vent-sexing and feather-sexing, showing a matching rate of 93.1%.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.80-88
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• 2020

With the issuance of one-week fine dust emergency reduction measures in March 2019, the public's anxiety about fine dust is increasingly growing. In order to assess the application of air purifying plant-based bio-filters to public facilities, this study presented a method for measuring pollutant reduction effects by creating an indoor environment for continuous discharge of particle pollutants and conducted basic studies to verify whether indoor air quality has improved through the system. In this study conducted in a lecture room in spring, the background concentration was created by using mosquito repellent incense as a pollutant one hour before monitoring. Then, according to the schedule, the fine dust reduction capacity was monitored by irrigating for two hours and venting air for one hour. PM₁₀, PM_2.5, and temperature & humidity sensors were installed two meters front of the bio-filters, and velocity probes were installed at the center of the three air vents to conduct time-series monitoring. The average face velocity of three air vents set up in the bio-filter was 0.38±0.16 m/s. Total air-conditioning air volume was calculated at 776.89±320.16㎥/h by applying an air vent area of 0.29m×0.65m after deducing damper area. With the system in operation, average temperature and average relative humidity were maintained at 21.5-22.3℃, and 63.79-73.6%, respectively, which indicates that it satisfies temperature and humidity range of various conditions of preceding studies. When the effects of raising relatively humidity rapidly by operating system's air-conditioning function are used efficiently, it would be possible to reduce indoor fine dust and maintain appropriate relative humidity seasonally. Concentration of fine dust increased the same in all cycles before operating the bio-filter system. After operating the system, in cycle 1 blast section (C-1, β=-3.83, β=-2.45), particulate matters (PM₁₀) were lowered by up to 28.8% or 560.3㎍/㎥ and fine particulate matters (PM_2.5) were reduced by up to 28.0% or 350.0㎍/㎥. Then, the concentration of find dust (PM₁₀, PM_2.5) was reduced by up to 32.6% or 647.0㎍/㎥ and 32.4% or 401.3㎍/㎥ respectively through reduction in cycle 2 blast section (C-2, β=-5.50, β=-3.30) and up to 30.8% or 732.7㎍/㎥ and 31.0% or 459.3㎍/㎥ respectively through reduction in cycle 3 blast section (C-3, β=5.48, β=-3.51). By referring to standards and regulations related to the installation of vegetation bio-filters in public facilities, this study provided plans on how to set up objective performance evaluation environment. By doing so, it was possible to create monitoring infrastructure more objective than a regular lecture room environment and secure relatively reliable data.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.791-797
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• 2007

We studied the inhibitory effect of solvent fractions from doenjang on mutagenicity using Salmonella typhimurium TA100 in Ames test. We also investigated the effect of solvent fractions from doenjang on the growth of tumor cells and the production of interleukin-2 (IL-2). The treatment of dichlorormethane and ethylacetate fractions (2.5 mg/assay) from doenjang to Ames test system inhibited aflatoxin B$_1$ (AFB$_1$) induced mutagenicity by 96% and 97%, respectively, and showed a higher antimutagenic effect than other solvent fractions. In case of N-methyl-N'-nitro-N-nitrosoguamidine (MNNG) induced mutagenicity, the ethylacetate fraction showed the highest inhibitory effect (by 75%) among the other sol-vent fractions, although the inhibitory effect was not stronger compared to AFB$_1$ induced mutagenicity. The treatment of dichloromethane and ethylacetate fractions markedly inhibited the growth of Yac-1 (by 80% and 94%, respectively) and sacroma-180 cancer cells (by 60% and 96%, respectively) after 4 days of incubation at 37${\circ}$C. To elucidate the immunological mechanism of antitumor activity of doenjang, spleen cells of Balb/c mouse were exposed to the dichloromethane and ethyl-acetate fractions for 24 hours at 37${\circ}$C . The culture supernatants following the treatment of djchloromethane and ethylacetate factions to spleen cells increased the production of IL-2. These results indicated that the anticarcinogenic effect of doenjang was mediated by the production of IL-2.