• 제목/요약/키워드: Relative temperature

검색결과 3,812건 처리시간 0.034초

Greenhouse environment analysis -Distributions and Variations of Temperature , Relative humidity Illumination , Carbon dioxide and Wind Velocity-

  • Kim, Y.B;Park, J.C.;Song, H.K.;Paek, Y.
    • 한국농업기계학회:학술대회논문집
    • /
    • 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
    • /
    • pp.478-486
    • /
    • 1993
  • For satisfactory greenhouse culture, environmental factors must be kept in proper conditions. Therefore, it is important to know relations between environmental conditions and greenhouse systems. In this study, the environment variations and distributions in different types of greenhouses were measured and analyzed. The elements of environment analyzed were temperature , relative humidity, illumination, carbon dioxide and wind velocity. The analyzed greenhouse types were three different types. One of them, A type, was propagation model type by government and the other one, B type, was multiple continuous arches type which was made by farmers himself. The last one, C type, was single arch type which has no environment control system without manual temperature keeping method. The results of this study can be used for reasonable greenhouse environments managements and control.

  • PDF

산림토양에서의 Phenanthrene, Pyrene, Benzo(a)pyrene의 휘발 속도: 토양온도와 대기습도의 영향

  • 이신향;김현숙;이동수
    • 한국지하수토양환경학회:학술대회논문집
    • /
    • 한국지하수토양환경학회 2001년도 추계학술발표회
    • /
    • pp.99-102
    • /
    • 2001
  • The soil-to-air fluxes of three PAHs(Phenanthrene, Pyrene, Benzo(a)pyrene) from a laboratory contaminated forest soil were investigated in experimental microcosms. The effects of soil temperature(45$^{\circ}C$, $25^{\circ}C$, 5$^{\circ}C$) and relative humidity(0%, 100%) were investigated according to existence of the humic layer(O layer) over the mineral layer(A layer). Volatilization flux experiments were carried out for a period of 96 hrs. The resulting PAHs volatilization fluxes from the different conditions were quantified and compared. In the mineral layer, highest volatilization flux among the individual PAHs was Phenanthrene >Pyrene> Benzo(a)pyrene on the conditions of 45 $^{\circ}C$, RH=100%. In the humic layer over the mineral layer, maximum volatilization flux was Phenanthrene on the condition of 45$^{\circ}C$, RH=0%. Results from flux experiments showed that volatilization fluxes of PAHs were dependent on soil temperature. Existance of humic layer over the mineral layer delayed transportation to the air of especially heaveir molecular PAHs. But, if humic layer is contained water sufficiently, it is possible that volatilization fluxes are enhanced by water convective flux according to variation of soil temperature and air relative humidity.

  • PDF

Spatial Interpolation of Meteorologic Variables in Vietnam using the Kriging Method

  • Nguyen, Xuan Thanh;Nguyen, Ba Tung;Do, Khac Phong;Bui, Quang Hung;Nguyen, Thi Nhat Thanh;Vuong, Van Quynh;Le, Thanh Ha
    • Journal of Information Processing Systems
    • /
    • 제11권1호
    • /
    • pp.134-147
    • /
    • 2015
  • This paper presents the applications of Kriging spatial interpolation methods for meteorologic variables, including temperature and relative humidity, in regions of Vietnam. Three types of interpolation methods are used, which are as follows: Ordinary Kriging, Universal Kriging, and Universal Kriging plus Digital Elevation model correction. The input meteorologic data was collected from 98 ground weather stations throughout Vietnam and the outputs were interpolated temperature and relative humidity gridded fields, along with their error maps. The experimental results showed that Universal Kriging plus the digital elevation model correction method outperformed the two other methods when applied to temperature. The interpolation effectiveness of Ordinary Kriging and Universal Kriging were almost the same when applied to both temperature and relative humidity.

벼 및 현미의 평형함수율/평형상대습도 (EMC/ERH of Rough Rice and Brown Rice)

  • 최병민
    • Journal of Biosystems Engineering
    • /
    • 제30권2호
    • /
    • pp.95-101
    • /
    • 2005
  • Adsorption and desorption experiments were carried out on rough rice and brown rice (Nampyung) at 5, 15, 25, 35, $45^{\circ}C$ for moisture contents between 8.7 and $25\%$ (db). The method employed was to measure the equilibrium relative humidity (ERH) of air in contact with the grain under static conditions, using an electronic hygrometer The effects of temperature and moisture contents were investigated, and the measured values were fitted to the modified Henderson, the modified Chung-Pfost, the modified Halsey and the modified Oswin model. The ERHs of rough rice and brown rice decreased with an decrease in moisture content and temperature, and the effects of temperature was no significant at moisture content of $25\%$ (db). Equilibrium moisture content (EMC) of brown rice was higher than rough rice at same temperature and relative humidity. Desorption EMC is higher than the adsorption, but there is no significant difference between desorption and adsorption EMC in moisture content near $25\%$ (db) at rough rice and near 9, 21 and $25\%$ (db) at brown rice. The modified Oswin model was the best in describing the adsorption EMC and the modified Chung-Pfost model was the best in describing the adsorption ERH of rough rice. The modified Oswin model was the best in describing the adsorption EMC/ERH of brown rice. The modified Chung-Pfost model was the best in describing the desorption EMC/ERH of rough rice and brown rice.

기후요소가 온열질환자수에 미치는 영향 (The Effects of Climate Elements on Heat-related Illness in South Korea)

  • 정다은;임숙향;김도우;이우섭
    • 한국기후변화학회지
    • /
    • 제7권2호
    • /
    • pp.205-215
    • /
    • 2016
  • The relationship between the climate and the number of heat-related patients in South Korea was analysed in this study. The number of the patients was 1,612 during the summer 2011 to 2015 according to the Heat-related Illness (HRI) surveillance system. The coefficient of determination between the number of the patients and the daily maximum temperature was higher than that between the number of them and the other elements: the daily mean/minimum temperature and relative humidity. The thresholds of daily maximum and minimum temperature in metropolitan cities (MC) were higher than those in regions except for MC (RMC). The higher the maximum and minimum temperature became, the more frequently the heat-related illness rate was observed. The regional difference of this rate was that the rate in RMC was higher than that in MC. Prolonged heat wave and tropical night tended to cause more patients, which continued for 20 days and 31 days of maximum values, respectively. On the other hand, the relative humidity was not proportional to the number of the patients which was rather decreasing at over 70% of relative humidity.

Thermodynamics of Small Electron-Bound Water Clusters

  • Lee, Sik;Lee, Han-Myoung
    • Bulletin of the Korean Chemical Society
    • /
    • 제24권6호
    • /
    • pp.802-804
    • /
    • 2003
  • The relative stabilities of weak binding clusters are sensitive to temperature due to the entropy effect. Thus, here we report significant changes in relative stabilities between two low-energy electron-water trimer structures and those between three low-energy electron-water pentamer structures, as the temperature increases. The trimer and pentamer show structural changes around 200 K.

유리표면에 진공증착된 금박막의 전기전도도의 습도 의존성 (Humidity Dependence of Electrical Conductivity of Vacuum Evaporated Au Films on Glass)

  • 이동영;박현수
    • 한국세라믹학회지
    • /
    • 제24권6호
    • /
    • pp.572-578
    • /
    • 1987
  • The vacuum evaporated Au films on soda-lime glasses were measured by the electrical conductivity with the variation of the annealing time, relative humidity, and temperature. Au films structures were observed by scanning Electron Microscope and X-ray Diffractometer. As the annealing time and temperature increased, the electrical conductivity was increased due to the migration or annihilation of defects, but the electrical conductivity was decreased as with the relative humidity increased. Au films by XRD and SEM examination showed the negligible effect of chemical reactions.

  • PDF

폴리이미드 박막을 이용한 집적화 습도센서 (An Integrated Humidity Sensor Based on Thin Polyimide Films)

  • 안광호;민남기
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1994년도 하계학술대회 논문집 C
    • /
    • pp.1388-1390
    • /
    • 1994
  • A polyimide-based capacitive humidity sensor has been designed and fabricated using silicon integrated-circuit technology, and its performance measured. The sensor showed excellent linearity, low temperature coefficient, and low hysteresis over a wide range of relative humidity and temperature. The signal conditioning circuits for detecting relative humidity and converting it to voltage have been developed based on a charge redistribution between capacitors using switched -capacitors.

  • PDF

시설원예용 제습기 개발 (Development of Dehumidifier for Protected Horticulture)

  • 연광석;강금춘;강연구;유영선;김영중;백이
    • Journal of Biosystems Engineering
    • /
    • 제30권2호
    • /
    • pp.110-113
    • /
    • 2005
  • Relative humidity of air In the greenhouse has to be maintained at 70 to 80 percents to provide a better growth condition of crops. To control relative humidity of air in the greenhouse, a dehumidifier functioning by refrigeration cycle was designed and manufactured in this study. And, results of its performance test in the greenhouse site were reported. The developed dehumidifier has separated condenser and evaporator in the heat exchanger part in order to increase dehumidifying capacity at a low temperature condition. When the conditions of incoming air into the dehumidifier were temperature of $15\~25^{\circ}C$ and relative humidity of $0\~95\%$, quantity of condensed water per hour, ie, dehumidification rate was $4.7\~7.0\;kg/hr$. Relative humidity difference was not greater than 5 percents at various locations in the greenhouse due to proper distributing of dehumidified air through vinyl duct. Thermal energy output from the developed dehumidifier was about 8,5000 kcal/hr that was 7 percents of maximum greenhouse heating load of 10 a.

내부 온습도 측정을 통한 초기재령의 콘크리트 내부 습도 및 수화열 변화 특성 분석 (Experimental Investigation on Variation of Internal Relative Humidity and Temperature due to Hydration of Concrete at Early Age)

  • 홍성기;박철우;박성재;강태성;김희성
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
    • /
    • pp.741-744
    • /
    • 2008
  • 콘크리트 구조물의 품질관리를 위해 양생초기 내부 수화열 분석 및 습도 거동에 대한 정확한 측정 및 분석은 구조물의 내구성 및 장기공용성의 향상을 위하여 필수적이라 할 수 있다. 특히 최근에는 대형 콘크리트 구조물 및 고성능 콘크리트 시공사례가 증가함에 따라 이러한 초기 온습도 거동에 대한 중요성이 증가하고 있는 실정이다. (2005 정진훈) 일반적으로 콘크리트 초기 재령시 수화반응에 의한 수화열은 내적 및 외적 구속을 받고 있는 콘크리트 구조체에 대하여 온도응력을 발생시켜 양생 초기 균열 및 지속적인 인장응력 영향을 가지게 한다. 또한 대기 온도 및 습도 그리고 콘크리트 양생환경에 의한 급속한 표면 및 내부습도 변화는 콘크리트 건조수축을 유발하며 온도응력과 더불어 초기 콘크리트 구조물에 피해를 좋지 않은 영향을 미쳐 내구성 및 장기공용성을 저하시킨다.최근 이러한 초기 거동의 분석의 중요성 인식되면서 초기 거동에 대한 많은 연구가 이루어져왔다. 하지만 수화열 분석에 비하여 수분분포 및 거동 분석에 대한 연구는 계측의 어려움으로 인하여 매우 미비한 실정이다. 또한 내부 습도를 직접적이며 정확하게 측정하기보다는 대기 습도 및 표면습도에 의한 내부습도 변화를 예측하는 연구가 진행되었었다. 본 연구에서는 콘크리트 초기 재령시 내부의 수화열에 의한 온도 분포 거동과 수화반응 및 건조에 의한 수분 분포 거동을 동시에 직접적으로 측정할 수 있는 편리하고 신뢰성 있는 측정 기법을 제시하고 그에 따른 콘크리트 구조물의 온습도 거동을 측정 분석하는데 있다.

  • PDF