• 제목/요약/키워드: Lead in air

검색결과 621건 처리시간 0.024초

중등학교 교실의 이산화탄소(CO2) 관리를 위한 지능형 창호개폐 작동 프로세스 (Intelligent and Responsive Window Opening-Closing Operation Process for Carbon Dioxide(CO2) Management of Secondary School Classroom)

  • 최윤영;이현수
    • 교육시설 논문지
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    • 제25권4호
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    • pp.19-30
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    • 2018
  • The school classroom is a common living place where students spend 7 to 14 hours a day to prepare for their careers. Therefore, if the ventilation of the classroom is not properly performed, it may lead to the deterioration of learning ability due to the unclear air. The concentration of carbon dioxide in the classroom is reported to be high, and the increase in carbon dioxide concentration has a negative effect on the learner's academic performance. In this context, the purpose of this study is to propose a methodology for intelligent and responsive window opening-closing operation process that can reduce the concentration of $CO_2$ in the classroom in order to build a support space that can create an effective teaching-learning environment for adolescents. The specific objectives are as follows. First of all, we define the concept of window opening-closing operation. Secondly, twe develop the operation process of window opening-closing. Thirdly, we develop an algorithm for real-time window opening and closing (process) (Window Opening-Closing Operation Process). Finally, we verify the intelligent responsive window opening-closing operation process through developing examples of window opening-closing operation process using the parametric design program. This study is a preliminary study to develop algorithms necessary for window opening-closing operation. Based on the first-order algorithm, We simulated window opening-closing operations according to a hypothetical scenario. As a result, This study can show that the window is open and close depending on the $CO_2$ concentration, but the $CO_2$ concentration in the room is higher than outdoors. Consequentially, we suggest that it is necessary to develop an algorithm to supplement these results because window is often not working when the temperature difference between indoor and outdoor in winter is large.

Er,Cr:YSGG 레이저를 조사한 임플란트 표면의 주사전자현미경적 연구 (SCANNING ELECTRON MICROSCOPIC STUDY OF IMPLANT SURFACE AFTER Er,Cr:YSGG LASER IRRADIATION)

  • 조필귀;민승기;권경환;김영조
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제28권5호
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    • pp.454-469
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    • 2006
  • Today, there is considerable evidence to support a cause-effect relationship between microbial colonization and the pathogenesis of implant failures. The presence of bacteria on implant surfaces may result in an inflammation of the peri-implant mucosa, and, if left untreated, it may lead to a progressive destruction of alveolar bone supporting the implant, which has been named as peri-impantitis. Several maintenance regimens and treatment strategies for failing implants have been suggested. Recently, in addition to these conventional tools, the use of different laser systems has also been proposed for treatment of peri-implant infections. As lasers can perform excellent tissue ablation with high bactericidal and detoxification effects, they are expected to be one of the most promising new technical modalities for treatment of failing implants. It is introduced that Er,Cr:YSGG laser, operating at 2780nm, ablates tissue by a hydrokinetic process that prevents temperature rise. We studied the change of the titanium implant surface under scanning electron microscopy after using Er,Cr:YSGG laser at various energies, irradiation time. In this study, Er,Cr:YSGG laser irradiation of implant fixture showed different effects according to implant surface. Er,Cr:YSGG laser in TPS surface with RBM not alter the implant surface under power setting of 4 Watt(W) and irradiation time of 30sec. But in TPS surface with $Ca_3P$ coating alter above power setting of 2W and irradiation time of 10sec. TPS surface with RBM showed microfracture in 4W, 30sec and TPS surface with $Ca_3P$ coating showed destruction of fine crystalline structure, melting in excess of 2W, 10sec. We concluded that proper power setting, air, water of each implant surface must be investigated and implant surface must be irradiated under the damaged extent.

항행안전시설 안전문화에 대한 안전성숙도가 운영성과에 미치는 영향에 관한 연구 (A Study on the Effect of Safety Maturity on Operational Performance of Navigational Aids Facilities Safety Culture)

  • 이영길;김기웅;박성식
    • 한국항행학회논문지
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    • 제25권5호
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    • pp.327-335
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    • 2021
  • 항행안전시설은 유선통신, 무선통신, 인공위성, 불빛, 색채 또는 전파를 이용하여 항공기의 항행을 돕기 위한 시설로 악기상 상태에서도 항공기가 안전하게 운항할 수 있도록 각종 정보를 제공하는 시설이다. 항행안전시설은 항공기 운항의 모든 과정에서 이용되는 시설이며, 동 시설에 문제가 발생하는 경우 항공기 운항의 지연, 결항 발생 및 대형 항공사고로 이어져 막대한 인명과 재산피해를 불러올 수 있다. 항행안전시설 관리운영에 있어 안전문화에 대한 안전성숙도에 따라 여러 가지 성과를 가져오게 될 것이다. 본 연구의 목적은 항행안전시설의 관리 운영에 있어 안전문화에 대한 안전성숙도가 조직원 성과, 고객 성과 및 사회적 성과 등의 운영성과에 미치는 영향을 조사하는 것이다. 구조 방정식 모델을 이용하여 분석 결과를 제시하였으며, 그 의미는 결론에 제시하였다.

건조방법에 따른 고춧가루의 품질특성 (Effects of Drying Methods on Quality of Red Pepper Powder)

  • 임용래;경예나;정헌상;김혜영;황인국;유선미;이준수
    • 한국식품영양과학회지
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    • 제41권9호
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    • pp.1315-1319
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    • 2012
  • 본 연구에서는 건조방법에 따른 고춧가루의 품질 변화를 비교하기 위하여 한 가지 품종의 고추를 PE House 건조, 열풍건조, 원적외선 방법을 이용하여 건조한 다음, 건조조건별로 고춧가루의 수분함량 변화, pH, ASTA value 및 capsaicinoids와 vitamin C의 함량을 조사하였다. 건조 후 고춧가루의 수분함량은 12.05~14.01% 함유한 것으로 나타났으며, pH는 건조 전 생고추인 4.93보다 다소 높은 5.00~5.54를 나타내었다. 고춧가루의 매운맛을 나타내는 총 capsaicinoids의 capsaicinoids의 함량은 PE House 건조에서 224.40 mg/100 g으로 가장 높게 나타났으며, 열풍 $70^{\circ}C$ 건조에서 191.87 mg/100g으로 가장 낮게 나타났다. 하지만 건조방법에 따른 capsaicinoids 함량이 유의적 차이를 보이지 않았기 때문에, 매운맛 함량의 변화는 큰 차이를 나타내지 않았다. 고춧가루의 대표적 항산화제인 vitamin C 함량은 다른 건조방법 및 조건에 비해 PE House, 열풍 $60^{\circ}C$과 원적외선 $60^{\circ}C$에서 596.60~648.31 mg/100 g으로 높은 수준의 함량을 나타내었다. 소비자가 고춧가루를 선택하는데 중요한 요소로 작용하는 ASTA value는 126.68~156.77로 건조방법 및 조건에 따른 유의적 차이를 나타내지 않았다. 따라서 고추의 건조방법 및 조건을 낮은 온도 조건에서의 열풍, 원적외선 건조방법으로 결정한다면 고춧가루의 vitamin C의 손실을 최소화하고 PE House 건조에 비해 신속하며 오염을 예방하는 고품질의 고춧가루 제품을 생산할 수 있을 것으로 생각된다.

영농형 태양광 시설 하부 논에서의 농업환경 관측 및 시설 외부 환경과의 비교 (Agro-Environmental Observation in a Rice Paddy under an Agrivoltaic System: Comparison with the Environment outside the System)

  • 강민석;손승원;박주한;김종호;최성원;조성식
    • 한국농림기상학회지
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    • 제23권3호
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    • pp.141-148
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    • 2021
  • 솔라 쉐어링이라고도 불리는 영농형 태양광은 작물의 광포화점 이상의 태양광을 솔라 패널을 이용한 발전에 활용하는 개념으로, 잉여 태양광 차단에 따른 지면에 입사하는 태양복사 에너지의 감소로 인한 증발산량 감소와 함께 지면 냉각 효과로 메탄 배출량도 줄이는 효과를 가져올 수 있어 기후 스마트 농업을 구현할 수 있는 기술로 기대되고 있다. 본 연구에서는 파주 영농형 태양광 시설 하부 및 외부 논에 상/하향 장/단파 복사, 기온, 습도, 지온, 수온, 풍향, 풍속 등을 관측하는 자동기상관측장비를 설치하여 시설 하부와 외부의 농업환경을 관측하고 비교함으로써, 영농형 태양광이 농가에 태양광 발전을 통한 부가적인 수입을 안기면서 재배 시 발생하는 물 소비와 메탄 배출을 줄이는 기후 스마트 농업 실현에 적합한지 그 가능성을 확인해 보았다. 관측 기간 동안 영농형 태양광 시설 하부의 평균 일사량은 노지 일사량의 약 70% 정도였으며, 영농형 태양광 시설 하부 논과 노지 논에서 기온의 차이는 거의 없었지만 지온과 수온은 명확한 차이가 확인되었다. 실제로 이러한 환경의 차이가 물 소비량 및 온실가스 배출량 감소로 이어지는지 플럭스 실측을 통한 확인이 요구된다.

후두에 발생한 파종성 황색종 1예 (A Case of Xanthoma Disseminatum with Laryngeal Involvement)

  • 박진수;이용우;이상혁;진성민
    • 대한후두음성언어의학회지
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    • 제26권1호
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    • pp.58-62
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    • 2015
  • Xanthoma disseminatum (XD) is a benign, non-Langerhans cell histiocytosis characterized by disseminated xanthomatous lesions with face, flexures, and mucosa. Most of XD develops in mucocutaneous lesions including skin, oral cavity and pharynx, however laryngeal involvement is uncommon. While the natural course of XD is usually benign and often self-limiting, but XD develop in critical anatomical locations may result in morbidity and mortality. Localized mucous lesions in oropharynx and larynx lead to dysphagia, dyspnea and air way obstruction. The diagnosis of XD was based on clinical, histological and immunohistochemical findings. The treatment is complex and non-consensual. Local treatment with cryotherapy, radiotherapy, surgery, and carbon dioxide lasers have been attempted with various results. Systemic medication with peroxisome proliferator-activated gamma receptors, statins, fenofibrate, chlorodeoxyadenosine, cyclophosphamide, doxycycline, and cyclosporine have also been reported, but none have proven particularly successful. A 59-year-old man presented with respiratory symptoms because of laryngeal involvement of XD. We had to remove the obstructive lesion for relieving the symptoms. We experienced XD in Larynx that was rare in otorhinolaryngology. So we report this case with review of literatures.

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도로 침하에 따른 아스팔트 파손에 대한 연구 (A case study for the asphalt damage with the subsidence)

  • 강인원;조상훈;심철우;김동철
    • 대한안전경영과학회지
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    • 제14권3호
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    • pp.175-181
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    • 2012
  • This example was able to focus on the long usage of the pavement that it was merely through the oxidation of the asphalt pavement which it could contact with on the road in the industrial housing complex and correlation regulation of the asphalt subsidence with the load in basic Infra of the configuration. The problem in conjunction with the subsidence (transformation) was interpreted as a problem of the subsidence of each pavement layer to lead the subsidence of the road or the transformation to packaging side asphalt pavement, but the traffic number of times of the heavy vehicle highlights for main problems with the road where is concentrated. In the case of general asphalt paving, it thinks it exposes light, and to study a general phenomenon for the asphalt transformation and a cause for a pavement construction method and the property of material used for pavement and a complement method by the case study at this time of the compound with the heavy vehicle traffic that it can become clear that small success transformation occurs at a point in time when 1-2 years more pass, and a fatigue rift occurs by ultraviolet rays, the oxidation with the contact with the air afterwards, and described beginning to use by the above.

우드칩을 연료로 하는 열병합발전소의 회분 퇴적 및 설비 고장 원인 분석 (Investigating the Cause of Ash Deposition and Equipment Failure in Wood Chip-Fueled Cogeneration Plant)

  • 송민지;김우철;김희산;김정구;이수열
    • Corrosion Science and Technology
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    • 제22권3호
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    • pp.187-192
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    • 2023
  • The use of biomass is increasing as a response to the convention on climate change. In Korea, a method applied to replace fossil fuels is using wood chips in a cogeneration plant. To remove air pollutants generated by burning wood chips, a selective denitrification facility (Selective catalytic reduction, SCR) is installed downstream. However, problems such as ash deposition and descaling of the equipment surface have been reported. The cause is thought to be unreacted ammonia slip caused by ammonia ions injected into the reducing agent and metal corrosion caused by an acidic environment. Element analysis confirmed that ash contained alkali metals and sulfur that could cause catalyst poisoning, leading to an increase in the size of ash particle and deposition. Measurement of the size of ash deposited inside the facility confirmed that the size of ash deposited on the catalyst was approximately three times larger than the size of generally formed ash. Therefore, it was concluded that a reduction in pore area of the catalyst by ash deposition on the surface of the catalyst could lead to a problem of increasing differential pressure in a denitrification facility.

수영장에서 소독제 분말 가스 폭발에 의한 흡입화상 2례 (Two Cases of Inhalation Injury Caused by An Explosion of Two Different Chemical Disinfectants(Sodium Dichloroiso Cyanurate & Calcium Hypochlorite) in a Swimming Pool)

  • 이수진;박은영;김미란;이건희;김광남
    • Clinical and Experimental Pediatrics
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    • 제46권2호
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    • pp.198-202
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    • 2003
  • 국내 소아에서는 아직 화학 물질 흡입화상에 대한 보고가 없는 상태로 저자들은 수영장 창고에서 수영장 물의 살균, 소독제인 이염화이소시안산 나트륨과 차아염소산 칼슘을 잘못 혼합하던 중 발생한 소독제 분말 가스 폭발 반응에 노출되어 급격한 호흡 곤란증이 있었던 증례 2례를 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

Flux-gradient similarity theory 적용에 따른 태화산 산림지표 토양NO플럭스 분석 (Practical Use of Flux Gradient Similarity Theory for Forest Soil NO Flux at Mt. Taewha)

  • 김득수
    • 한국대기환경학회지
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    • 제30권6호
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    • pp.531-537
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    • 2014
  • Terrestrial vegetation has been known as a main source of biogenic volatile organic compounds (BVOCs). Isoprene and monoterpene among the BVOCs are most abundant species emitted by forests, and have a significant impact on atmospheric chemistry. Abundancy of these species could lead to an increase or decrease in the production of natural tropospheric ozone in forests, depending on the nitric oxide (NO) concentration. Soil is the most significant source of natural NO. Understanding of NO emission from forest soil could be critical in evaluation of air quality in the forest area. Flux-gradient similarity theory (FGST) was applied for practical use to estimate forest soil NO emission at Mt. Taewha where is available micro-meteorological data near surface monitoring from flux tower. NO fluxes calculated by FGST were compared to flux results by flow-through dynamic chamber (FDC) measurement. Surface NO emission trends were shown between two different techniques, however their magnitudes were found to be different. NO emissions measured from FDC technique were relatively higher than those from theoretical results. Daily mean NO emissions resulted from FGST during Aug. 13, 14 and 15 were $0.28{\pm}8.45$, $2.17{\pm}15.55$, and $-3.18{\pm}13.65{\mu}gm^{-2}hr^{-1}$, respectively, while results from FDC were $2.26{\pm}1.44$, $5.11{\pm}3.85$, and $2.23{\pm}6.45{\mu}gm^{-2}hr^{-1}$. Trends of daily means were shown in similar pattern, which NO emissions were increasing during late afternoon ($r^2$=0.04). These emission trends could be because soil temperature and moisture influence importantly soil microbiology.