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악취 발생 저감을 위한 양돈 사육 시설 개선에 따른 비용 편익 분석
김기연,김현태,고한종 경상국립대학교 농업생명과학연구원 2019 농업생명과학연구 Vol.53 No.6
This study was conducted to provide a reliable objectivity for the current government policy that open swine house is changed to enclosed swine house by cost benefit analysis. The cost of the open swine house and enclosed swine house was divided into installation and operation and then estimated based on related literature data and field survey results. The benefit was estimated by applying the Delphi survey method to livestock environmental experts. Based on the results obtained from this study, regardless of pig farm scale, both the open and enclosed swine houses were estimated to have a benefit/cost ratio (B/C ratio) of over 1, which resulted in economic benefits from pig production. It was, however, estimated that the B/C ratio of enclosed swine house in the small, medium and large scale of pig farms was relatively higher than that of open swine house. In conclusion, it is recommended that existing open swine houses be changed to enclosed swine houses in order to effectively manage pig odor as well as economic advantages in terms of legal authorization. Especially, in case of the large pig farm where the B/C ratio is the highest, it is reasonable to immediately move the existing open swine house to the enclosed swine house. 본 연구의 목적은 악취 발생 저감을 위해 국내에서 최근 권고되는 밀폐(무창)형 돈사와 기존 개방형 돈사의 비용 편익을 분석하여 이러한 추진 방향의 객관적 타당성을 확보하는 데 있다. 두 돈사 유형의 비용은 설치비와 운용비로 구분한 후 관련 문헌 자료와 현장 조사 결과를 근거로 추정하였고, 편익은 축산 환경 전문가들을 대상으로 한 델파이 설문 조사 기법 적용을 통해 추정하였다. 비용 편익 분석 결과, 양돈규모에 상관없이 개방형과 밀폐형 돈사 모두 편익/비용 비율이 1 초과로 추정되어 돼지 생산에 따른 경제적 이익이 창출되는 것으로 분석되었다. 하지만 소규모, 중규모, 대규모 양돈 농가 모두 밀폐(무창)형 돈사의 편익/비용 비율(B/C ratio)이 개방형 돈사보다 상대적으로 모두 높은 것으로 추정되었다. 결론적으로 기존 양돈 농가들의 인·허가 시 경제성 우위 측면뿐만 아니라 축산 악취의 효율적 관리를 위해서도개방형 돈사를 밀폐(무창)형 돈사로 변경하도록 권고해야 하며, 특히 편익/비용 비율이 상대적으로 가장높은 수치를 보인 대규모 농가인 경우 이를 이행 조치하는 것이 합리적이라 판단된다.
서울시 일부 지하철역 내 부유 진균, 입자상 물질, 이산화탄소의 분포 양상
김기연,박재범,김치년,이경종,Kim, Ki-Youn,Park, Jae-Beom,Kim, Chi-Nyon,Lee, Kyung-Jong 대한예방의학회 2006 Journal of Preventive Medicine and Public Health Vol.39 No.4
Objectives: The aims of this study were to examine the level of airborne fungi and environmental factors in Seoul metropolitan subway stations and to provide fundamental data to protect the health of subway workers and passengers. Methods: The field survey was performed from November in 2004 to February in 2005. A total 22 subway stations located at Seoul subway lines 1-4 were randomly selected. The measurement points were subway workers' activity areas (station office, bedroom, ticket office and driver's seat) and the passengers' activity areas (station precincts, inside train and platform). Air sampling for collecting airborne fungi was carried out using a one-stage cascade impactor. The PM and CO2 were measured using an electronic direct recorder and detecting tube, respectively. Results: In the activity areas of the subway workers and passengers, the mean concentrations of airborne fungi were relatively higher in the workers' bedroom and station precinct whereas the concentration of particulate matter, $PM_{10}\;and\;PM_{2.5}$, were relatively higher in the platform, inside the train and driver's seat than in the other activity areas. There was no significant difference in the concentration of airborne fungi between the underground and ground activity areas of the subway. The mean $PM_{10}\;and\;PM_{2.5}$ concentration in the platform located at underground was significantly higher than that of the ground (p<0.05). Conclusions: The levels of airborne fungi in the Seoul subway line 1-4 were not serious enough to cause respiratory disease in subway workers and passengers. This indicates that there is little correlation between airborne fungi and particulate matter.
Direct observation of asymmetric magnetization reversal in Fe/Cr/Fe thin films
김기연,신성철,유천열,김동현 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
We report our experimental nding showing that there exists an asymmetric magnetization reversal behavior along the direction normal to the easy axis in Fe/Cr/Fe thin lms. Interestingly enough, the magnetoresistance and the Kerr hysteresis loops are found to be quite asymmetric between the decreasing- and the increasing-eld branches of the loop in the applied-eld direction normal to the easy axis whereas they are found to be symmetric in the direction parallel to the easy axis. To clarify the microscopic details of the asymmetric magnetization reversal, we use a magneto-optical microscope magnetometer to carry out a direct time-resolved observation of the domain evolution patterns at each switching eld. The magnetization reversal is revealed to take place with a fast, abrupt, simple 180-degree domain-wall conguration at the switching eld in the increasing-eld branch while it is found to take place with an irregular and complex conguration at the switching eld in the decreasing-eld branch.
1P-40 Polyol에 따른 Waterborne polyurethane dispersion(WPUD)의 물성 변화
김기연,신승한,박희웅 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1
Solvent-based polyurethane은 우수한 성능을 가졌지만, 유기용매의 휘발 등으로 인한 환경오염 문제 때문에 유해성 논란이 계속 되어 waterborne polyurethane dispersion으로 대체되고 있는 추세이다. WPUD는 합성 시 낮은 volatile organic compound 함량을 가져 환경 친화적이라는 장점이 있어 환경문제를 개선시킬 수 있으나, 기존의 solvent-based PU에 비해 내수성과 여러 물성이 떨어지는 단점이 있다. 이를 개선시키기 위해서 다른 hard segment를 첨가하였다. Ionomer인 Dimethylolpropionic acid(DMPA)를 기반으로 한 WPUD를 Polytetramethylenetherglycol(PTMG), Polycarprolactone(PCL) 등의 polyol을 사용하여 합성하였다. Polyol effect를 관찰하기 위해 polyol의 종류와 분자량을 변화시켜 합성하였고 이에 따른 film의 인장강도와 연신율을 UTM을 통해 확인하였다. GPC, Particle size analysis(PSA) 등을 측정하여 분자량과 입자 크기를 관찰하였고, 상온에서 건조시킨 film의 건조거동을 평가하였다.
김기연,Kim, Gi-Yeon 한국건강관리협회 1985 건강소식 Vol.9 No.8
불타는 태양은 우리와 함께하고 여름의 낭만이 우리를 손짓하지만 여름의 낭만이 우리를 손짓하지만 여름을 맞이한 피부는 높은 기온과 강한 자외선으로 피지 분비가 많아지고 피부내 자연보습성분인 NMF와 수분이 감소되어, 피부는 거칠어 집니다.