• The Korean Journal of Mycology
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• v.46 no.4
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• pp.393-403
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• 2018

Bio-aerosols transported by the air have been considered as the major source of dispersal agents that contaminate agricultural products. Unseen fungal spores are known sources of bio-aerosols that harm mushroom and human health during mushroom cultivation. This study was conducted to obtain basic data on the concentration and species distribution of fungi present in the indoor air of oak mushroom cultivation houses in Korea. In 2015 and 2016, we sampled and analyzed indoor airborne fungal spores 21 times from 13 oak mushroom cultivation farms located in six different provinces. The concentration of airborne fungi ranged from $1.30{\times}10^2$ to $1.59{\times}10^4cfu/m^3$. Surprisingly, in 20 sampling cases, the fungal concentration exceeded $500cfu/m^3$, which is recommended as the indoor air quality standard by the Ministry of Environment, Korea. A total of 450 fungi were isolated and identified to belong to 33 genera and 46 species. Among the identified fungi, human pathogens (4 genera and 4 species) and plant pathogens (10 genera and 13 species) were present. In addition, Trichoderma harzianum, Trichoderma atroviride, and Trichoderma longibrachiatum, which are detrimental species that affect mushroom health, were found 17 out of 21 sampling times. Our results provide evidence that indoor air quality should be improved for better management of mushroom cultivation houses.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.107-119
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• 2013

바이오매스 가스화는 세계적인 증가 추세에 있는 에너지 수요를 충족할 수 있는 기술 중의 하나이다. 바이오매스 가스화를 통해서 농업 폐기물 등 다양한 바이오매스 자원을 에너지로 전환할 수 있고 $CO_2$ 배출량 또한 줄일 수 있다. 본 연구에서는 COMSOL$^{(R)}$ 3.4 소프트웨어를 이용하여 바이오매스 원료와 운전 조건에 따른 가스화 효율 및 합성가스 조성의 변화를 분석하였다. 원료와 구동조건을 최적화하기 위해 가스화 모델을 세우고 원료와 구동조건을 달리하여 합성가스의 성분을 분석 및 예측하였다. 이 모델은 물리적인 실험을 통해 알고 있는 조건을 통해서 합성가스 성분을 시간에 따라 예측할 수 있다. 모델을 이용하여 함수비 5~30 %, 공기중 산소함량 5~50 %, 공기공급 유량 5~45 L/min, 온도 973~1273 K의 조건에서 합성가스의 성분을 예측한 결과 실제 실험 결과와 일치하는 것을 알 수 있다. 모델링 결과 양질의 합성가스를 생산하려면 원료의 회분함량이 적어야 하고 수소 함량이 높은 합성가스를 생산하려면 반응 온도가 높게 유지되고 원료의 함수비가 높아야 한다. 가스화장치의 온도를 높이면 합성가스의 성분 중 CO의 함량이 많아지고, CO의 함량이 많아지면 가스의 발열량이 높아지는 것을 알 수 있다. 또한 CO의 농도가 높고 발열량이 높은 합성가스를 생산하기 위해서는 ER값은 작아야 한다.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.324-337
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• 1990

To assess the effectiveness of the interventions in working environment and personal hygiene for the occupational exposure to the lead, 156 workers (116 exposed subjects and 40 controls) of a newly established battery factory were examined for their blood lead concentration (Pb-B) in every 3 months up to 18 months. Air lead concentration (Pb-A) of the workplaces was also checked for 3 times in 6 months interval from August 1987. Environmental intervention included the local exhaust ventilation and vacuum cleaning of the floor. Intervention of the personal hygiene included the daily change of clothes, compulsory shower after work and hand washing before meal, prohibition of cigarette smoking and food consumption at the work site and wearing mask. Mean Pb-B of the controls was $21.97{\pm}3.36{\mu}g/dl$ at the preemployment examination and slightly increased to $22.75{\pm}3.38{\mu}g/dl$ after 6 months. Mean Pb-B of the workers who were employed before the factory was in operation (Group A) was $20.49{\pm}3.84{\mu}g/dl$ on employment and it was increased to $23.90{\pm}5.30{\mu}g/dl$ after 3 months (p<0.01). Pb-B was increased to $28.84{\pm}5.76{\mu}g/dl$ 6 months after the employment which was 1 month after the initiation of intervention program. It did not increase thereafter and ranged between $26.83{\mu}g/dl\;and\;28.28{\mu}g/dl$ in the subsequent 4 tests. Mean Pb-B of the workers who were employed after the factory had been in operation but before the intervention program was initiated (Group B) was $16.58{\pm}4/53{\mu}g/dl$ before the exposure and it was increased to $28.82{\pm}5.66{\mu}g/dl$(P<0.01) in 3 months later (1 month after the intervention). The values of subsequent 4 tests remained between 26.46 and $28.54{\mu}g/dl$. Mean Pb-B of the workers who were employed after intervention program had been started (Group C) was $19.45{\pm}3.44{\mu}g/dl$ at the preemployment examination and gradually increased to $22.70{\pm}4.55{\mu}g/dl$ after 3 months(P<0.01), $23.68{\pm}4.18{\mu}g/dl$ after 6 months, and $24.42{\pm}3.60{\mu}g/dl$ after 9 months. Work stations were classified into 4 parts according to Pb-A. The Pb-A of part I, the highest areas, were $0.365mg/m^3$, and after the intervention the levels were decreased to $0.216mg/m^3\;and\;0.208mg/m^3$ in follow-up tests. The Pb-A of part II was decreased from $0.232mg/m^3\;to\;0.148mg/m^3,\;and\;0.120mg/m^3$ after the intervention. Pb-A of part III and W was tested only after intervention and the Pb-A of part III were $0.124mg/m^3$ in Jannuary 1988 and $0.081mg/m^3$ in August 1988. The Pb-A of part IV not stationed at one place but moving around, was $0.110mg/m^3$ in August 1988. There was no consistent relationship between Pb-B and Pb-A. Pb-B of the group A and B workers in the part of the highest Pb-A were lower than those of the workers in the parts of lower Pb-A. Pb-B of the workers in the part of the lowest Pb-A incerased more rapidly. Pb-B of group C workers was the highest in part I and the lowest in part IV. These findings suggest that Pb-B is more valid method than Pb-A for monitoring the health of lead workers and intervention in personal hygiene is more effective than environmental intervention.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2003.05a
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• pp.111-114
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• 2003

산소는 인간의 신체 및 정신 활동에 필수적인 물질이며, 특히 뇌 기능에 중요한 역할을 수행한다. 본 연구에서는 일반 공기 중의 산소 농도(21%) 환경에 비해 외부에서 고 농도(30%)의 산소 공급이 인지 능력 중 특히 공간 지각 능력에 어떠한 변화를 유발하는지 관찰하고자 한다. 8명의 남자 대학생(평균 23.5세)을 본 연구의 실험 참여자로 선정하였다. 21%와 30% 산소 농도를 각각 8L/min의 양으로 일정하게 공급할 수 있는 장치를 개발하여, 마스크를 통하여 실험 참여자에게 전달하였다. 공간 지각 능력 측정으로 위해 각각 20문항을 포함하는 두 개의 문제지를 제작하였고, 과제 수행 결과로부터 정답률과 평균 반응 시간을 산출하였다. 평균 정답률은 21%와 30% 산소 농도에서 각각 50.63 $\pm$ 8.63과 62.50 $\pm$ 9.64 이었고, 두 농도간의 통계적 유의차가 발생하였다. 평균 반응 시간의 21%와 30% 산소 농도에서 각각 6.60 $\pm$ 0.77〔sec〕이었고, 두 농도간의 통계적 유의차가 발생하지 않았다. 본 연구 결과로부터 외부에서의 고농도의 산소 공급이 공간 지각 능력 증가에 긍정적인 영향을 미친다는 결론을 도출할 수 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.254-257
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• 2017

As a part of the development of aircraft gas turbines, combustion performance tests have been conducted in the single combustor sector. The effects of change in the amount of air supplied to the main combustion zone to the performance of the combustor, such as a pollutant emission, a liner temperature distribution and an exit temperature patterns, were studied. Emissions of CO and NOx increased with the main air-ratio and exit temperature pattern was improved. When changing the pattern of the dilution holes, it was shown that the temperature patterns on the exit plane of the combustor and the surface of liner changed depending on the main flame structure and mixing with diluent air. These observations will be applied to combustor liner designs to improve combustor durability and emissions reduction performance.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.245-246
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• 2002

일반적으로 대기 중 환경기준을 제어하기 위해서는 각 배출원에서 발생되는 오염물질의 배출강도를 정량적으로 평가 할 필요가 있다. 최근 들어, 휘발성 유기화합물질의 환경학적 중요성이 밝혀지면서 이 물질에 대한 대기 중 농도분포는 어떤 양상을 보이며 이에 영향을 미치는 각 배출원에서 비산배출(fugitive emission)되는 VOCs 종류와 농도에 대한 조사가 필요하게 되었다. VOCs 배출원은 모든 국가가 유사하겠으나 배출원별 VOCs의 배출기여도는 각국의 경제 및 산업구조의 특성에 따라 달라질 수 있다. (중략)

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.11a
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• pp.39-40
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• 2004

초등학교에서의 실내공기 중 미생물 농도를 측정하여 본 결과 수업시간에 비하여 쉬는 시간에 아이들의 활동도에 따른 bacteria의 농도가 2.07배 증가하였고 유의성이 있는 것으로 나타났다. 에어컨을 가동 후 15분에서 미생물 농도가 최대가 되었으며, 이때의 농도가 2시간동안 가동하였을 때의 농도에 비해 12.29배 높게 나타났다. 이러한 에어컨 오염은 에어컨 내부 오염원에 의한 원인인 것으로 사료된다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.381-382
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• 2001

Bioaerosol은 인공적으로 생성되거나, 혹은 자연적으로 발생하는 생물학적 기원(biological origin)을 가진 물질로 정의한다. 실내공기 중에서 이러한 Bioaerosol 발생의 중요한 원인으로는 실외에서 유입되는 경우와 건물의 HVAC 시스템에 의한 경우, 실내에 거주하고 있는 사람이나 동물에 의한 경우가 대표적이다. 특히 이 세 가지 오염원 중에서 실내 거주자와 동물이 가장 중요한 역할을 하는 것으로 보고되고 있다(Pastuszka 등, 2000). (중략)

• Membrane Journal
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• v.30 no.3
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• pp.173-180
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• 2020

As the demand for fossil fuels continues to increase worldwide, carbon dioxide (CO₂) concentration in the air has increased over the centuries. The way to reduce CO₂ emissions to the atmosphere, carbon capture and sequestration (CCS) technology have been developed that can be applied to power plants and factories, which are primary emission sources. According to the climate change mitigation policy, direct air capture (DAC) in air, referred to as "negative emission" technology, has a low CO₂ concentration of 0.04%, so it is focused on adsorbent research, unlike conventional CCS technology. In the DAC field, chemical adsorbents using CO₂ absorption, solid absorbents, amine-functionalized materials, and ion exchange resins have been studied. Since the absorbent-based technology requires a high-temperature heat treatment process according to the absorbent regeneration, the membrane-based CO₂ capture system has a great potential Membrane-based system is also expected for indoor CO₂ ventilation systems and immediate CO₂ supply to smart farming systems. CO₂ capture efficiency should be improved through efficient process design and material performance improvement.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.317-324
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• 2014

Environmental tobacco smoke (ETS) samples were collected separately in mainstream and side-stream smoke using a self-designed smoking machine, and a total 40 of PM2.5 was collected with low volume air sampler at indoor environments with and without ETS in Daejeon, Korea. About 20 trace elements including toxic metals like As, Cr, Mn, Se, V, and Zn were determined in PM2.5 and ETS samples by instrumental neutron activation analysis (INAA). It is found that the emission factors of K, Cl, Na, and Al were much higher than those of toxic elements for both mainstream and side-stream smoke. The average concentration of PM2.5 was enriched by 1.5 times at smoking area ($58.7{\pm}18.1{\mu}g/m^3$) than at smoking free area ($38.6{\pm}12.7{\mu}g/m^3$). The concentration ratio of each element between smoking and smoking free area were ranged from 1.1 to 6.0 except Cu (1.0); especially, Ce (6.0), La (5.2), K (2.3), and Co (2.0) showed higher ratio, which suggests that the ETS is one of the possible increasing factors of PM2.5 and elemental concentration at indoor environment.