• Title/Summary/Keyword: Air contents

검색결과 1,428건 처리시간 0.029초

유지계 PC감수제의 고형분율 변화에 따른 시멘트 모르타르의 기초적 특성 분석 (Analysis of Fundamental Properties of Cement Mortar with Change of Solid Contents of PC Type Maintenance System Water Reducing Agent)

  • 김민상;이재진;현승용;문병룡;한민철;한천구
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2017년도 추계 학술논문 발표대회
    • /
    • pp.145-146
    • /
    • 2017
  • This research aimed to analyze the fundamental properties of cement mortar accompanying the change of the solid contents of the maintenance type PC water reducing agent. As a result of the experiment, it was found that the properties of fresh mortar show a tendency to decrease as the solid contents decreases in the case of flow and air contents, and the decrease width with time is small. It was found that the compressive strength of the hardened mortar has almost no difference due to the change of the solid fraction.

  • PDF

PTFE함량에 따른 아연공기전지의 Cathode 특성연구 (Effects of PTFE Contents on Characteristics of Cathode for Zn Air Batteries)

  • 김지훈;엄승욱;문성인;윤문수;김주용;육경창;박정후
    • 전기화학회지
    • /
    • 제6권3호
    • /
    • pp.203-207
    • /
    • 2003
  • 아연공기전지는 공기중의 산소를 사용하므로 cathode의 재활용이 가능하다는 장점이 있으며 아연의 이론용량이 820(mAh/g)로 상당히 높다 또한 아연공기전지는 저율방전에서 방전말기까지 아주 평탄한 방전전압을 유지한다. 그러나, 고율방전에서는 방전전압이 낮아지고 에너지가 감소하며 cathode에 포함되어 있는 PTF도의 함량에 따라 저항 및 기공율에 많은 변화를 보이고 있다. 이에 본 연구에서는 전지의 에너지, 방전용량, 방전전압, DC저항, GSM, ASTM에 의한 기공율 측정을 통해 cathode내의 PTFE함량이 아연공기전지에 미치는 영향을 연구하였다. 그 결과 결합제의 함량이 감소할수록 전지의 특성이 향상되었으며 $15wt\%$일 때 가장 우수한 전지특성을 얻을 수 있었다.

초 . 중 . 고등학교 교과서의 환경관련 내용분석연구 (An Analysis on the Contents of the Environmental Health in the Primary, Middle and High School Textbooks)

  • 남철현;류장근;최연정;황연자
    • 한국환경보건학회지
    • /
    • 제20권4호
    • /
    • pp.98-117
    • /
    • 1994
  • To provide data for the contents regarding environmental health (environmental hygiene, environmental pollution) in the textbooks of primary, middle and high schools, a total of 243 textbooks was analysed for two months from May, to July 31, 1993. Among the total 52844.50 pages, 1.65% was related to the environmental health, which account for 870.00 pages. In the textbooks by school level, the rate of the contents regarding environmental health in primary school was 1.63% (148.75 pages). that of middle school was 1.96% (243.25 pages) and that of high school was 1.53% (478.00 pages). The area of environmental hygiene was 0.24% (129.25 pages) and that of environmental pollution was 1.40% (740.75 pages) which is slightly high. In the field of environmental hygiene, the rate of the contents in the middle school textbooks was 0.53% which was the higher than that of the primary and high school textbooks. The rate of environmental pollution area was not significantly different by school level but the number of the pages was the higher at the high school than that of the primary and middle schools, which account for 428.8 pages. The contents related by the areas were as follows: 1. Contents related to environmental hygiene 1) Among environemtnal hygiene contents, the rate of housing sanitation was the highest as 0.14% (73.00 pages), that of air environment was 0.06% (33.00 pages) and that of water supply sanitation was 0.03% (17.25 pages). The portion of air environment was 5.00 pages in the primary school textbooks and that of housing sanitation at the middle and high schools was each 35.0 pages, 35.50 pages, which was the more than that of other fields. By school year, there was no contents related at the 1st and 2nd grades but were 4.75 pages at the 4th grade which were the more than those of other grades. At the 5th grade, water supply sanitation part was found but not air environment. Housing sanitation was found at the 3rd, 5th grades and insect or rodent control was at the 3rd, 4th, 5th, 6th grades. 2) In the middle school textbooks related to environmental health, 41.0 pages were included in the textbooks of pysical education, the highest number. The next was 19.5 pages in home economics, 2.8 pages in social studies and 3.00 pages in others. The contents of air environment were found in the textbooks of physical education and science, those of water supply and housing sanitation were in home economics and physical education and those of insect control were found 0.5 pages in home economics only. 3) In the high school textbooks, the highest number was 27.8 pages of home economics and the next was 11.5 pages of others, 7.8 pages of physical education, 2.0 pages of science and 0.3 pages of social studies. Air environment parts were included in the textbooks of science, physical education and home economics and water sanitation was in home economics, physical education and others. Housing sanitation was showed in home economics and social studies, on the other side the contents of insect or rodent control was found in home economics and physical education. 4) By the subjects related to environmental hygiene in the primary, middle and high school textbooks, 51.0 pages of home economics were the highest portion. It was also revealed that 49.5 pages of physical education, 14.5 pages of others, 13.5 pages of science and 0.8 pages of social studies were included. The number of 33.0 pages of air environment portion was distributed into 9.75 pages of science, 19.0 pages of physical education and 4.25 pages of others. Among 17.3 pages of water sanitation, 3.5 pages of home economics, 11.3 pages of physical education and 2.5 pages of others were included. Housing sanitation portions were 73.0 pages, which were distributed into 46.5 pages of home economics, 0.5 pages of social studies, 18.3 pages of physical education and 7.8 pages of others. 5) The number of photo, figure, illustration and table related in the primary school textbooks was 31. Among them, the number of photos was 21, that of figures or illustrations was 9 and that of table was 1. The number of 63 in the middle school textbooks was classified into 3 photos, 32 figures or illustrations and 28 tables. At the high school, the number of 56 was included 2 photos, 41 figures or illustrations and 13 tables.2. Contents related to environmental pollution 1) In the field of environmental pollution, the rate of water pollution was 0.39% (203.3 pages), that of air pollution was 0.31% (161.5 pages) that of soil pollution was 0.1% (57.3 pages), that of refuse disposal was 0.08% (40.3 pages) and others was 0.5% (278.5 pages) by school level, the rate of water pollution in the primary, middle and high schools was each 40.5, 48.0, 118.8 pages and that of air pollution was each 20.8, 38.3, 102.5 pages. 2) Environmental pollution areas were not inserted in the textbooks at the 1st grade of the primary school but foqnd 5.5 pages at the 2nd grade, 30.5 pages at the 4th grade, 36.3 pages at the 5th grade and a,9.5 pages at the 6th grade. Water pollution was included from the 2nd grade, air pollution and refuse disposal from the 3rd grade and soil pollution from the 5th grade. 3) In the middle school textbooks, environmental pollution was distributed into 90.25 pages of science, 42.8. pages of physical education, 20.5 pages of social studies, 19.5 pages of others and 4.0 pages of home economics. At the high school, the contents were found 191.3 pages in science, 119.3 pages in others, 88.5 pages in social studies, 28.5 pages in physical education and 1.3 pages in home economics. 4) By subjects of the primary, middle and high schools, the portion of environmental pollution was classified into 322.2 pages of science, 195.0 pages of social studies, 138.8 pages of others, 76.3 pages of physical education and 8.5 pages of home economics. Air and soil pollution parts were not found in the subjects of home economics. 5) The number of photo, figure or illustration and table related in the primary school textbooks was 218. Among them, the number of photos was 61, that of figures or illustrations was 149 and that of tables was 8. At the middike school, the number of 153 was distributed into 99 photos, 34 figures or illustrations and 20 tables. The number of 129 found in the high school textbooks was included 129 photos, 73 figures or illustrations and 100 tables.

  • PDF

베트남 저품위 비산재의 미연탄소 함량 저감 연구 (Study on Reduction Unburned Carbon Contents in Low Quality Fly Ash from Vietnam)

  • 김기석;이재원;이동원;민경남
    • 자원리싸이클링
    • /
    • 제29권2호
    • /
    • pp.37-47
    • /
    • 2020
  • 베트남은 화력발전을 중심으로 한 발전용량 확보 계획을 추진 중이며, 석탄화력발전소로부터 배출되는 석탄재의 대량처리 방안 확보가 시급한 실정이다. 이 연구는 베트남에서 발생하는 석탄재 중 미연탄소 함량이 높아 재활용이 어려운 저품위 비산재의 미연탄소 함량을 국제 비산재 활용기준인 6% 미만으로 낮추는 것을 목표로 하였다. 저품위 비산재를 배출하는 발전소의 비산재 품질을 조사한 결과, 비산재의 미연탄소 함량은 5.3~23.6%로 미연탄소 함량이 높고 불규칙하였다. 공기분급과 정전선별을 적용하여 비산재를 처리한 결과, 미연탄소 함량 9.8%까지는 분급 단일공정으로, 23.6%까지의 비산재는 분급과 정전선별로 구성된 복합공정으로 미연탄소 함량을 6% 미만으로 감소시킬 수 있었다.

침엽수(針葉樹) 제재(製材)의 4계절별(季節別) 천연건조(天然乾燥) 과정(過程)의 비교(比較) (Comparison of Air-Drying Process in Four Seasons for Some Softwood Lumbers)

  • 정희석;이남호;이준호;권주용
    • Journal of the Korean Wood Science and Technology
    • /
    • 제25권1호
    • /
    • pp.28-36
    • /
    • 1997
  • Several thick board and dimension lumbers of Japanese larch(Larix leptolepis), Dahurian larch(Larix gmelini) and radiata pine(Pinus radiata) air-dried in four different seasons to compare air-drying process. Patterns of air-drying curves were influenced by climatological conditions and limber thickness. The initial drying rates of summer were the highest, followed those of fall, spring and winter. The drying times to equilibrium moisture contents for four seasons were nearly the same except for winter. However, the drying time for winter required twice more time than the other seasons. The drying time of dimension lumbers required 1.3 times more than boards. The final moisture contents were lowest during spring, highest during winter and similar between summer and fall.

  • PDF

대기오염(大氣汚染) 지역의 해송엽내(海松葉內) 수용성(水溶性) 황(黃), 불소(弗素), WAX, 엽록소(葉綠素) 함량(含量) 및 엽(葉) 생장(生長)의 변화와 생물지표성(生物指標性) (Contents of Sulfur, Fluorine, Wax and Chlorophyll in Needle Tissue and Needle Growth of Pinus thunbergii as Bioindicators of Air Pollution)

  • 김준선;김용환;이한열
    • 한국산림과학회지
    • /
    • 제82권4호
    • /
    • pp.347-353
    • /
    • 1993
  • 여천공업단지(麗川工業團地)에서 배출되는 대기오염물질(大氣汚染物質)이 해송(海松)의 생육에 미치는 영향을 구명하기 위하여 3개 지역에서 해송엽내(海松葉內) 오염물질(汚染物質), 엽록소(葉綠素) 및 wax함량과 침엽(針葉)의 생장량을 1991년 7월 초에서 10월 초까지 4주마다 조사하였다. 수용성(水溶性) 황(黃)과 불소(弗素)는 채취시기에 관계없이 오염원(汚染源)에 가까운 지역일수록 높았으며 수용성(水溶性) 황(黃)은 7월 초에서 10월 초까지 큰 변동이 없었으나 불소(弗素)는 지속적으로 증가하였다. 엽록소함량(葉綠素含量)은 대기오염(大氣汚染)이 경미한 지역에서는 대조지역(對照地域)과 큰 차이를 보이지 않았으나 대기오염(大氣汚染)이 심한 지역에서는 급격히 감소하였고 침엽(針葉)의 wax함량은 오염도(汚染度)가 높을수록 점차 감소하였다. 침엽(針葉)의 생장은 7월 초까지는 각 조사기간에 차이가 없었으나 시간이 흐를수록 오염지역내 해송(海松) 엽(葉)의 생장(生長)은 둔화되었다. 따라서 해송엽내(海松葉內) 수용성(水溶性) 황(黃) 및 불소함량(弗素含量)의 증가와 wax함량의 감소는 여천지역의 대기오염(大氣汚染)에 의한 것으로 생육중반 이후에는 대기오염(大氣汚染)에 대한 생물지표(生物指標)로 이용될 수 있는 것으로 판단되었다. 엽록소함량(葉綠素含量)의 감소는 오염(汚染)이 심한 지역에서 비교적 이른 시기에 생물지표성(生物指標性)을 보이는 것으로 생각되었다. 한편 침엽(針葉)의 왜소화(矮小化)는 장기간의 대기오염(大氣汚染)에 의한 영향으로 생육기 후반부에 나타나기 때문에 초기에 침엽(針葉)의 길이만으로 대기오염(大氣汚染)을 파악하는 것은 적절하지 못하였다.

  • PDF

냉풍건조 곶감과 천일건조 곶감의 이화학적 품질특성 (Physicochemical Characteristics of Cold-Air Dried Persimmons and Traditional Dried Persimmons)

  • 이수원;문혜경;이원영;김종국
    • 한국식품저장유통학회지
    • /
    • 제18권4호
    • /
    • pp.481-487
    • /
    • 2011
  • 본 연구는 냉풍건조 곶감과 천일건조 곶감의 이화학적 품질특성을 조사하였다. 반건시 및 건시 모두 수분함량과 수분활성도에 있어서 냉풍건조 곶감이 가장 낮은 값을 나타내었다. 조단백질은 유의적인 차이가 나타났으나, 조지방은 유의적인 차이가 나타나지 않았다. 조회분과 가용성무질소물 함량은 냉풍건조 곶감에서 다소 높게 나타났다. 꽂감의 가용성 고형물 함량은 반건시의 경우 냉풍건조 반건시, 건시가 각각 40.12 $^{\circ}Brix$, 52.29 $^{\circ}Brix$로 가장 높은 값을 나타내었다. 곶감의 색도는 L값(lightness), a값(redness) 및 b값(yellowness)에서는 냉풍건조 곶감이 전통곶감에 비해 상대적으로 색에 있어서는 낮은 값을 보여주어 어두운 색을 나타내었다. 조직감을 측정한 결과 반건시의 경우 조직감에 있어서 3개 시료구에서 유의적인 차이가 거의 없었으나, 건시의 경우 냉풍건조 곶감의 수분이 상대적으로 적어 hardness, gumminess, chewiness의 값이 상대적으로 다소 높게 나타났다. 유리당은 6개 시료구 모두 fructose와 glucose만 검출되었으며 유리 아마노산은 17종 함유되어 있었고, aspartic acid, glutamic acid 및 alanine 순으로 그 함량이 많았다. 냉풍건조 곶감이 천일건조에 의해 생산되는 전통 곶감보다 위생적이며 건조조건을 자유롭게 조절할 수 있기 때문에 건조기간을 획기적으로 단축할 수 있으며 균일한 품질의 우수한 곶감생산을 할 수 있을 것으로 생각된다.

단위수량 변화에 따른 혼화제 종류 및 첨가량별 콘크리트의 특성 분석 (An Analysis of Concrete Characteristics by Admixing Agent and Additive Contents According to the Change of Unit-Water)

  • 류현기;우종권;조명근
    • 한국건축시공학회지
    • /
    • 제7권4호
    • /
    • pp.139-144
    • /
    • 2007
  • The purpose of this study is to analyze concrete characteristics by admixing agent and additive contents according to the change of unit-water to identify its effect on compressive strength. First of all, as for flesh concrete, overall unit-water showed a tendency to decrease as component inclusion rate of admixing agent was increased. In addition, air content showed a tendency to increase by increasing WR, WB, NP series admixing agent contents, on the other hand, the change of air content was gentle by around $1.5{\pm}0.5%$ for S, T, M series agents. Bulk density showed an inverse proportion to the change of air content. As for hardened concrete, expression rate of 3-day age compressive strength was generally decreased for S, T, WR, WB, NP, M series admixing agent component. Also, expression rate of 7-day age compressive strength showed an excellent record for S, M series agents, and expression rate of 28-day age compressive strength showed a tendency to increase more than plain on the whole.

불포화토의 거동예측을 위한 구성식 개발(I) -불포화토의 거동특성 연구- (Development of Constitutive Model for the Prediction of Behaviour of Unsaturated Soil(I) -Study of Characteristics of Unsaturated Soil-)

  • 송창섭;장병욱
    • 한국농공학회지
    • /
    • 제36권4호
    • /
    • pp.87-94
    • /
    • 1994
  • The aim of the work descrihed in this paper is to study a characteristics of an unsaturated soil for the different matric suctions. To this end, a series of suction controlled isotropic and triaxial compression tests is conducted on silty sands. Matric suction is controlled by the axis translation technique using high air entry ceramic disk. Total volume change, air and water volume changes are measured by the device made for the experiment. The specimens are compacted using a half of Proctor compaction energy and with the water contents of 5% drier than the optimum moisture contents. Isotropic compression and triaxial compression tests are conducted on the specimen at each equilibrium state of matric suction. From test results, volume changes and deviator stresses are analyzed at each state and their relationships are formulated.

  • PDF

Particle Size Distribution of Heavy Metals in the Urban Air of Seoul, Korea

  • Sohn, Dong-Hun;Heo, Moon-Young;Kang, Choon-Won
    • Archives of Pharmacal Research
    • /
    • 제12권3호
    • /
    • pp.214-218
    • /
    • 1989
  • Atmospheric particulate matters (A. P. M. ) were collected on quartz-fiber filters from March 1985 to May 1986, using the Andersen high-volume air sampler and contents of six heavy metals (Fe, Mn, Cu, Zn, Pb Ni) in the A. P. M. were determined by atomic absorption spectrophotometry. These heavy metals were divided into the three groups with respect to their particle size distribution. Fe and Mn were mainly associated with coarse particles (diameter > 2.0 $\mu$m), but Pb and Ni were related fine particles (diameter < 2.0 $\mu$m). Cu and Zn had mized size distributions in both of them. In the seasonal variation of heavy metals, the contents of Fe and Mn in spring and Ni and Pb in winter were higher than any other season. There were high mutual correlation between Fe and Mn coarse particles, and between Pb and Ni in fine particles.

  • PDF