• 제목/요약/키워드: Primary air

검색결과 875건 처리시간 0.033초

대형 도시폐기물 소각로의 연소특성을 파악하기 위한 수치 해석적 연구 (The Study of Numerical Simulation for Investigation of Combustion Characteristics in Municipal Waste Incinerator)

  • 전영남;엄태인;송형운
    • Korean Chemical Engineering Research
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    • 제40권6호
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    • pp.757-762
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    • 2002
  • 도시 폐기물의 효율적인 처리방법중의 하나인 소각은 폐기물을 감량화시키고 폐열도 이용할 수 있어 점차 증가하고 있다. 본 연구는 3차원 수치모델을 개발하여 대형 도시폐기물 소각로인 상무소각로에 연소특성과 최적의 운전조건을 파악하기 위하여 적용하였다. 아울러 개발된 3차원 수치모델을 실제 운전시와 동일한 조건으로 수치해석하여 얻어진 온도와 실측치 온도를 비교하여 모델의 적용성을 검증하였다. 본 모델을 적용하여 상무소각로의 소각시에 로내 연소특성을 파악한 결과 1차 공기가 충분하지 못하여 후연소영역에 불완전 연소생성물의 발생이 높지만 주화염대에서 2차 연소되어 불완전 연소생성물이 낮게 배출되고 연소효율이 좋은 특성을 가진다.

천연 해조장 생태계 서비스 및 편익지표에 관한 탐색적 연구 (An Exploratory Study on the Ecosystem Service and Benefit Indicators of Natural Seaweed Beds)

  • 강석규
    • 수산경영론집
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    • 제47권3호
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    • pp.53-69
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    • 2016
  • The purpose of this study is to explore the ecosystem service and benefit indicators of natural seaweed beds. Ecosystems of natural seaweed beds provide a wide range of services and benefits to human society including provisioning services, regulating services, supporting services, and cultural services. Indicators for each of the ecosystem services are chosen by marine plants ecologists and as follows. Ecosystem indicators of natural seaweed beds for provisioning services are well-being food(amount of seaweed harvested/amount of fish landed, fish biomass, area of natural seaweed beds, the number of species, contribution to the second production), raw materials(amount of biomass by breed, amount of aquaculture feed), genetic resources(amount of genetic material extracted, amount of genetic material contained by age and habitat), and medicinal resources(amount of medicinal material extracted). Ecosystem indicators of natural seaweed beds for regulating services are air purification(amount of fine dust/NOx or $SO_2$ captured), climate regulation(amount of $CO_2$ sequestered), waste treatment(amount of N, P stored, biochemical degradation capacity COD), and costal erosion prevention(length and change of natural coast line, amount of sediment prevented). Ecosystem indicators of natural seaweed beds for supporting services are lifecycle and maintenance(primary production, contribution to the second production) and gene pool protection(amount of compositional factors in ecosystem, introduced species). Ecosystem indicators of natural seaweed beds for cultural services are recreation and tourism(the number of visits of an area) and information for cognitive development(amount of time spent in education, research and individual learning about ecosystem of natural seaweed beds).

제품안전유공기관 평가지표개발에 관한 연구 (A Study on the Development of Evaluation Indicators for Product Safety and Air Supply Agencies)

  • 굴누라
    • 벤처혁신연구
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    • 제2권1호
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    • pp.23-31
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    • 2019
  • 본 연구의 주요 목표는 업계에서 제품 안전에 기여하는 조직을 평가하고 선정하기 위한 적절한 지표를 개발하는 것이다. 제품 안전 지표는 제품 안전 활동 및 시스템의 순서에 입력, 프로세스 및 출력을 포함하며, 그 지표들은 측정 가능하고 측정 불가능한 지수의 측면에서 제안된다. 세부 지표는 제품 안전 관리, 제품 안전을 위한 노력, 제품 안전성능 등 3가지 부분으로 구성된다. 이 지표들은 시스템 및 제품 안전의 관리 능력의 차이로 인해 기업 규모(대, 중, 소)별로 항목별로 구분된다. 지표를 합리적으로 얻기 위해 산업분야의 전문가 의견과 VOC를 검토한다. 그리고 직급과 수준(간부 대 노동자)에 따라 구분한다. 지표의 항목은 20개, 점수는 200개로 어느 경우든 동일하다. 지표들은 그의 산업에서 제품 안전의 발전에 기여하는 인력을 선택하는데 유용한 도구로 사용할 수 있다.

An Experimental Study of Water Vapor Pressure Change by Ambient Temperature at the Interface between Concrete and Fluid-Applied Membrane Layer

  • Ko, Jin-Soo;Kim, Byung-Yun;Park, Sung-Woo;Lee, Mun-Hwan;Lee, Sung-Bok
    • International Journal of Concrete Structures and Materials
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    • 제3권1호
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    • pp.15-23
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    • 2009
  • Over about 30% of problems in construction is related to water-leaking, and the loss from this problem can incur as much as three times the cost of initial construction. Thus, water vapor pressure is known to be the primary cause of defective waterproofing. Accordingly, the theories on the relationship between water pressure and temperature as well as damp-proofing volume of concrete and the change in vapor pressure volume were reviewed and analyzed in this study by making test samples after spraying a dampness remover and applying waterproofing materials to the prepared test specimens. The result of measuring water vapor pressure with the surface temperature of the waterproofing (fluid-applied membrane) layer at the experimental temperature setting of about $10^{\circ}C$, which is the annual average temperature of Seoul, indicated that (1) the temperature of the fluid-applied membrane elevated to about $40^{\circ}C$, and the water vapor pressure generated from the fluid-applied membrane was about 0.03 N/mm 2 when the surface temperature of the waterproofing layer was raised to about $80^{\circ}C$. (2) when the temperature of the fluid-applied membrane of the waterproofing layer was raised from $30^{\circ}C$ to $35^{\circ}C$, water vapor pressure of about 0.01 N/mm 2 was generated, and (3) when a thermal source was applied to the fluid-applied membrane (waterproofing) layer, the temperature increased from $35^{\circ}C$ to $40^{\circ}C$, and approximately $0.005\;N/mm^2$ of water vapor pressure was generated.

Bottom Ash 굵은골재 혼입에 따른 콘크리트의 강도특성에 관한 실험적 연구 (An Experimental Study on Strength Properties of Concrete using Bottom Ash Coarse Aggregate)

  • 장영일;박승범;이준;이병재;민정욱
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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    • pp.489-492
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    • 2008
  • 본 연구에서는 공공 및 민간의 전력수요가 증가함에 따라 화력발전소에서 다량으로 발생하고 있는 석탄재의 약 10${\sim}$15%정도를 차지하는 Bottom Ash를 유효재활용하기 위하여 Bottom Ash 굵은골재 혼입에 따른 콘크리트의 기초적 물성 및 강도특성을 분석하였다. 그 결과, Bottom Ash 굵은골재의 혼입률이 증가할수록 슬럼프는 감소하는 경향을 나타내었으며, 혼입하지 않은 경우에 비하여 약 4.5${\sim}$54.2%정도 감소하였다. 이에 비하여 공기량은 Bottom Ash 굵은골재를 혼입함에 따라 거의 영향이 없고 그 차이는 미소한 것으로 나타났다. 블리딩의 경우는 슬럼프의 경향과 유사하였으며 Bottom Ash 굵은골재의 혼입률이 증가함에 따라 초기의 블리딩이 현저하게 감소하였다. 또한, 압축강도는 Bottom Ash 굵은골재의 혼입률이 증가할수록 감소하였으며 혼입률 40%까지는 혼입하지 않은 경우에 비하여 약 1.1${\sim}$5.3%정도 감소하였고, 혼입률 60% 이상에서 급격히 감소하여 압축강도는 Plain의 약 85.2${\sim}$87.7%정도 발현하였다. 따라서, 콘크리트용 굵은골재로서 Bottom Ash 굵은골재를 대량으로 활용하기 위해서는 강도향상의 보강요소를 사용하는 것이 검토되어야 할 것으로 판단된다.

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스포츠쟈켓용 나일론/면 교직물의 설계조건에 따른 역학적 특성과 태 (Effect of Fabric Design Condition on the Mechanical Properties and Handle of Nylon/Cotton Union Fabrics for Sport Jacket)

  • 권오경;송민규
    • 한국의류산업학회지
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    • 제5권3호
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    • pp.267-272
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    • 2003
  • Tactel(Nylon66) union fabrics were woven with the specification of 70d/34f nylon as warp for sport wear jacket. Weft yarn has three types; 100% cotton yarn, nylon core-spun yarn and nylon-polyurethane covering yarn as weft. Fabric structers were plain, twill and satin weave structure with the air jet loom. The mechanical properties of 8 fabrics were measured with KES-F and primary Hand Values and Total Hand Values were calculated. The results of the study were as follows: 1) There was little difference among LTs of N/CM fabric groups. RT of the fabrics with CM100's was bigger than that of fabrics with CM80's, resulting that the fabrics with CM100's have better formability. In terms of weaving structure, twill fabrics have shape deformation. 2) In comparison of RTs with weft yarn type, RT of N-PU covering yarn was the highest, followed by Nylon core-spun yarn and cotton yarn. Thus, the fabric with N-PU covering yarn has better stability of shape deformation. 3) Stretch yarn could express an excellent silhouette formation and twill and satin structures were better structure to make curvature on human form. 4) 2HG/G value of nylon core-spun fabrics was larger than that of N/C fabrics, but the silhouette formation of N/C fabrics was excellent. 5) The RC of N/PU was the highest, followed by N/P, and N/CM. 6) Koski of N/PU fabrics was the highest, Numeri of N/PU and N/Co-I were relatively higher than the others. THVs of N/CM-IV and N/CO-II were lower than the others, resulting that, twill structure was better than plain structure for a sport wear uses.

고에너지 방사선치료에서 차폐물 경계부위의 선량분포에 관한 고찰 (A Study on the dosimetry in boundary of shielding block in high energy irradiation)

  • 김명세;김성규;신세원
    • Journal of Yeungnam Medical Science
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    • 제7권2호
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    • pp.115-120
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    • 1990
  • 18MeV 선형가속기와 코발트 원격치료기를 사용하여 방사선 조사면적 내에 차폐물이 있는 경우, 차폐물에 의한 산란선이 선량분포에 미치는 영향에 관하여 고찰하여 다음과 같은 결과를 얻었다. 1. 차폐물이 이루는 각이 예각일수록 산란선의 효과는 더 크게 나타났다. 2. 차폐물의 넓이가 좁을수록 산란선의 효과는 더 크게 나타났다. 3. 조사면적에 따른 출력특성은 선형적이지만, 차폐물에 의한 출력특성은 조사면적에 대하여 선형가속기는 거의 무관하게 나타났으며, 코발트 원격치료기는 기울기가 적은 선형성을 나타내었다.

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300 MW 급 유동층보일러에서 적정 층 물질량 산정 (Allowable Amount of Bed Inventory in a 300 MW Class Circulating Fluidized Bed Boiler)

  • 김우용;유호선
    • 플랜트 저널
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    • 제14권2호
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    • pp.33-38
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    • 2018
  • 본 연구에서는 순환유동층보일러의 베드가 과열되어 층 물질의 소결이 발생하고 노 내 유동물질에 의해 보일러튜브가 마모 되는 것을 최소화하기 위하여, 노 하부 베드의 층 물질량 조정을 통한 베드 온도 변화를 실험적으로 연구하였다. 실험은 300MW급 순환유동층보일러인 여수화력 2호기를 대상으로 하였으며 터빈출력, 석탄소비량, 공기량 등을 고정한 상태에서 층 물질 양을 감소시켜 베드 압력을 설계값 4.5KPa에서 2.5KPa까지 감소시켰다. 결론적으로 층 물질 양을 적정하게 줄이면 베드 온도가 저하 되나, 지속적으로 저하되지 않는 것을 확인 하였으며, 베드 압력 3.0KPa, 즉 베드 물질량 110 톤을 변곡점으로 하여 베드 온도는 상승하기 시작하였다. 층 물질량이 충분히 많은 상태에서, 층 물질량이 감소되면 베드 온도는 저하되며, 층 물질량이 적정량 보다 적으면 노 내 유동물질의 순환량 감소로 베드 온도는 상승함을 알 수 있었다. 또한 유동층보일러에서 베드 온도 변화는 단순히 층 물질의 양 뿐만 아니라, 보일러 용량 및 연료의 성상 등에 따라 변화 추이가 매우 다양하게 나타난다는 것을 알 수 있었다.

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양호교사의 역할인식과 일반교사 및 학생의 역할기대에 관한 일 연구 (A Study on Correlation between Role Perception Role Expectation of School Health Nurses, Teachers and Students in Urban Area)

  • 장광자
    • 대한간호학회지
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    • 제4권2호
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    • pp.107-120
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    • 1974
  • Healthy second generation is considered the wealth of the nation. Recant statistical data revealers that student population: primary through university, is 25% of population. Despite the fact that health education is one of the three most valued educational aims of Ministry of Education, students, teachers and parents seem reluctant to its value. In this contort, influences of school health nurses on this aspect of education can not bi disregarded This study is designed to investigate the status and working condition of school health nurses and analyse the correlation between role perception and role expectation of school health nursers. teachers and students. Prior to main study. pilot interviews with 10 of each group according to check-list are performed. Data for main study is collected through check-list from September 10 to October 10. 1973 from 100 of each group. All responses of questionnaire item are categories into 4 aspects; health education, environmental sanitation qualification of school health nurses and social aspect of school. Results of study are as follows; 1. Differences on role perception of school health nurses and role expectation of teachers is revealed-non-significant by .05〈P〈.10 level. while between students is shown significant difference by P〈.005 level, in health education role of school hearth nurses. 2. The environmental sanitation category of school health nurses role: non-significant difference is revealed between teachers and school health nurses by. 05〈P〈.10 level, and significant difference-is revealed by P〈.05 level. 3. Difference in value orientation of school health nurses' personal quality; students and teachers differ with school health nurses by P〈.025 1eve1. 4. Social aspect of school in the community aspect: non-significant differences are revealed by.05〈P〈.10 level between air three groups. Conclusions: 1. Role perception of school health nurses is most closely correlated with their role expectation. Some individual differences are noted between items, and aspects. 2. Role perception of school health nurses is more closely correlated than that of with role expectation of teachers than that of students. Some individual differences are noted between items, and aspects. 3. Consensus of role of school health nurses between each group is relatively Low: student is the lowest group. teacher the second, and school health nurses the highest.

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겨울철 광주지역 $PM_{2.5}$의 화학적 특성 조사 (Investigation of Chemical Characteristics of $PM_{2.5}$ during Winter in Gwangju)

  • 고재민;배민석;박승식
    • 한국입자에어로졸학회지
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    • 제9권2호
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    • pp.89-102
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    • 2013
  • 24-hr $PM_{2.5}$ samples were collected from January 19 through February 27, 2009 at an urban site of Gwangju and analyzed to determine the concentrations of organic and elemental carbon(OC and EC), water-soluble OC(WSOC), eight ionic species($Na^+$, $NH^{4+}$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$), and 22 elemental species. Haze phenomena was observed during approximately 29%(10 times) of the whole sampling period(35 days), resulting in highly elevated concentrations of $PM_{2.5}$ and its chemical components. An Asian dust event was also observed, during which $PM_{2.5}$ concentration was 64.5 ${\mu}g/m^2$. Crustal materials during Asian dust event contributed 26.6% to the $PM_{2.5}$, while lowest contribution(5.1%) was from the haze events. OC/EC and WSOC/OC ratios were found to be higher during haze days than during other sampling days, reflecting an enhanced secondary organic aerosol production under the haze conditions. For an Asian dust event, enhanced concentrations of OC and secondary inorganic components were also found, suggesting the further atmospheric processing of precursor gases during transport of air mass to the sampling site. Correlations among WSOC, EC, ${NO_3}^-$, ${SO_4}^{2-}$, and primary and secondary OC fractions, which were predicted from EC tracer method, suggests that the observed WSOC could be formed from similar formation processes as those of secondary organic aerosol, ${NO_3}^-$ and ${SO_4}^{2-}$. Results from principal component analysis indicate also that the observed WSOC was strongly associated with formation routes of the secondary organic and inorganic aerosols.