• 제목/요약/키워드: water supplying method

검색결과 69건 처리시간 0.035초

관수방식에 따른 숙주나물의 생장과 품온 변화 (Growth of Mungbean Sprouts and Commodity Temperature as Affected by Water Supplying Methods)

  • 강진호;류영섭;윤수영;전승호;전병삼
    • 한국작물학회지
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    • 제49권6호
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    • pp.487-490
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    • 2004
  • 두채생산에서 관수는 상면살수 방식과 하면담수 방식으로 대별된다. 본 연구는 관수방식에 따른 숙주나물의 생산과 상품성에 관한 정보를 제공하고자 중록1호를 공시재료로 상면살수와 하면담수 방식으로 대별되는 관수방식의 차이가 숙주나 물의 생장, 형태, 색도, 전단력과 재배용기내의 온도변화를 조사하고자 실시되었으며, 그 결과를 요약하면 다음과 같다. 1. 품질과 밀접히 관련된 세근은 하면담수 방법으로 재배할 경우 전혀 형성되지 않았던 반면, 상면살수 방법으로 재배할 경우 일부 개체에서 발생되는 것으로 조사되었다. 2. 하배축은 상면살수 방식에서, 뿌리는 하면담수 방식에서 길었으나, 하배축과 뿌리 길이를 합한 전체길이와 하배축 중간 및 자엽 바로 아래의 직경은 관수방법간에 차이가 없었다. 3. 개체당 전체건물중은 관수방법간에 차이가 없었던 반면, 전체생체중은 하면담수 방식보다 상면살수 방식에서 많았다. 이러한 차이는 주로 하배축 생체중의 차이에 기인되는 것으로 나타났다. 4. 두 관수방법 모두 재배중 플라스틱통 및 재배기내의 온도가 상승되었으나, 상면살수 방식에 이용되는 플라스틱 재배 통 내의 온도 상승이 큰 것으로 측정되었다. 이러한 온도 상승이 하면담수 방식보다 상면살수 방식에서 하배축 및 개체당 전체 생체중을 증가시킨 원인으로 해석되었다.

유막 코팅 노즐의 유동특성에 관한 CFD해석 (CFD Analysis on Flow Characteristics of Oil Film Coating Nozzle)

  • 정세훈;안승일;신병록
    • 한국유체기계학회 논문집
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    • 제11권5호
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    • pp.50-56
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    • 2008
  • Metal cutting operations involve generation of heat due to friction between the tool and the pieces. This heat needs to be carried away otherwise it creates white spots. To reduce this abnormal heat cutting fluid is used. Cutting fluid also has an important role in the lubrication of the cutting edges of machine tools and the pieces they are shaping, and in sluicing away the resulting swarf. As a cutting fluid, water is a great conductor of heat but is not stable at high temperatures, so to improve stability an emulsion type mixed fluid with water and oil is often used. It is pumped over the cutting site of cutting machines as a state of atomized water droplet coated with oil by using jet. In this paper, to develop cutting fluid supplying nozzle to obtain ultra thin oil film for coating water droplet, a numerical analysis of three dimensional mixed fluid Jet through multi-stage nozzle was carried out by using a finite volume method. Jet flow characteristics such as nozzle exit velocity, development of mixing region, re-entrance and jet intensity were analyzed. Detailed mixing process of fluids such as air, water and oil in the nozzle were also investigated. It is easy to understand complex flow pattern in multi-stage nozzle. Important flow Information for advance design of cutting fluid supplying nozzle was drawn.

단지계획지구 홍수저류지의 하천유지유량 공급방안 연구 (A Feasibility Study on Supplying Stream Minimum Flow Using Detention Storage in Developing Planned District)

  • 노재경;박현구
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2005년도 학술발표회 논문집
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    • pp.1219-1223
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    • 2005
  • This study was accomplished to confirm the possibility of supplying stream minimum flow from detention storage which was determined to reduce peak flows of flood within developing planned district. The results analyzed was summarized as follows; Firstly, Sin-gil district situated in Ansan city was selected, of which watershed area has $0.56km^2$. And detention storage was determined to $5,370m^3$ from analyzing flood volume by the SCS unit hydrograph method. Secondly, using Visual Basic ver 6.0, a detention storage water balance model was developed, in which simulation was based on conditioning storage inflow and outflow according to streamflow volume or rate state. And streamflow was simulated using the DAWAST model. Thirdly, detention operation scenarios were consisted of the combinations with inflow referencing streamflow of 5mm/day, 10mm/day and outflow referencing streamflow of 1mm/day, 2mm/day. The developed detention storage water balance model was operated to simulate daily water storages of detention sized on flood by scenarios. Stream minimum flows were able to be supplied during 209 days to 237 days per a year, total volume of stream minimum flows supplied for this period was analyzed to reach 27 to $55\% of yearly streamflow volume. If inflow criteria of streamflows to detention was considered to be established on a theoretical condition, it is expected to supply stream minimum flows of 20 to $30\% of yearly streamflow from stream to detention. Also to maximize function of supplying urban stream minimum flow from detention storages, sewage waters within developing planned district have to be treated and entered to detention inflow together with streamflows to enrich function of detention planned to reduce flood volumes.

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호우발생시 저수지 유입 부유사농도의 변화특성 연구 (A Study on the Variation of Suspended Sediment Concentration in the Reservoir due to a Rainstorm)

  • 장수형;박무종;윤용남
    • 한국수자원학회논문집
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    • 제37권1호
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    • pp.43-54
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    • 2004
  • 본 연구의 목적은 호우시에 저수지로 유입되는 토사유출량을 산정하고 저수지내 부유사 농도의 변화특성을 분석하여 저수지의 정량적 관리를 위한 자료를 제안하기 위한 것이다. 연구는 탐진댐에 적용되었으며 강우유출관계는 Huff의 강우분포와 Clark의 유역추적법을 사용하였으며, 저수지 추적은 Puls방법을 이용하였다. 토사유출량의 산정은 범양토양손실공식을 분포형 개념을 이용 단일호우에 대해 적용하여, 적정 빈도에 대해서도 적용가능하도록 하였다. 또한, 저수지내에서의 부유사 농도는 2차원 수리모형인 RMA-4를 이용하였다. 연구 수행결과 호우발생시 저수지에서의 취수가능기간에 대한 계산이 가능하며, 이를 이용하여 재현기간 및 강우량에 따른 여러 측면에서 용수공급에 따른 일정 수질 유지를 위한 자료를 제시하였다. 이는 강우시 저수지 수질관리를 위한 기초자료로 사용 가능하다.

An Improved Method for Monitoring of Soil Moisture Using NOAA-AVHRR Data

  • Fu, June;Pang, Zhiguo;Xiao, Qianguang
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.195-197
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    • 2003
  • Soil moisture is a crucial variable in research works of hydrology, meteorology and plant sciences. Adequate soil moisture is essential for plant growth; excesses and deficits of soil moisture must be considered in agricultural practices. There are already several remote sensing methods used for monitoring soil moisture, such as thermal inertia, vegetation water-supplying index, crop water stress index and multi-factor regression. In this paper, an improved method has been discussed which is based on the thermal inertia. We analyzed the problems of monitoring soil moisture using satellites at first, and then put forward an simplified method which directly uses land surface temperature differences to measure soil moisture. Also we have taken the influence of vegetation into account, and import NDVI into the model. The method was used in the study of soil moisture in Heilongjiang Province, China, and we draw the conclusion by the experiments that the model can evidently increase the precision of monitoring soil moisture.

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대구경 관로의 배수시간 산정을 위한 수치해석 기법 (A Numerical Method to Calculate Drainage Time in Large Transmission Pipelines Filter)

  • 신병호;최두용;정관수
    • 상하수도학회지
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    • 제31권6호
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    • pp.511-519
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    • 2017
  • Multi-regional water supply system, which installed for supplying multiple water demands, is characterized by large-sized, long-distance, tree-type layout. This system is vulnerable to long-standing service interruption when a pipe breaks is occurred. In this study, a numerical method is proposed to calculate drainage time that directly affects time of service interruption. To begin with, governing equations are formulated to embed the delayed drainage effect by the friction loss, and to resolve complicated connection of pipelines, which are derived from the continuity and energy equations. The nonlinear hydraulic equations are solved by using explicit time integration method and the Newton-Raphson method. The developed model is verified by comparing the result with analytical solution. Furthermore, the model's applicability is validated by the examples of pipelines in serial, in parallel, and complex layout. Finally, the model is utilized to suggest an appropriate actions to reduce the deviation of draining time in the C transmission line of the B multi-regional water supply system.

Growth and yield responses of rice varieties to various soil water deficit conditions under different soil types

  • Kikuta, Mayumi;Samejima, Hiroaki;Magoti, Rahab;Kimani, John M.;Yamauchi, Akira;Makihara, Daigo
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.322-322
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    • 2017
  • To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

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정수처리공정의 THMs 생성과 농도변화에 관한 연구 (A Study on Formation and Concentration of Trihalomethanes in Water Treatment Process)

  • 조덕희;안승구
    • 한국환경보건학회지
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    • 제23권2호
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    • pp.28-34
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    • 1997
  • This study was carried out to investigate the effects of prechlorination and algae growth on THMs generation. The sample water obtained from Paldang Dam which is a main source of raw water for the Seoul metropolitan area. THMs concentration in the sample water was investigated in water treatment process prechlorifiation, chemical coagulation, and sand filtration. And also, THMs concentration were analyzed in the water which cultured algae in laboratory. The results were as follows 1. The THMs concentration produced by prechlorination unit process were increased in control (not purified) but decreased in process of purification. 2. The THMs concertration can reduce by increasing the number of cleaning filters. 3. The main precursor in raw water for the THMs generation was supplied by algae growth. So as to reduce the THMs concentration in water supplying system, it is the best method to manage algae growth in water body of Paldang reservoir.

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의사 결정지원 모형에 의한 태양에너지 이용시스템의 경제성 고찰 (Economic Analysis on Solar Energy System with Decision Support Models)

  • 최인수;조덕기;최영희
    • 태양에너지
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    • 제10권1호
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    • pp.63-79
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    • 1990
  • 태양열 주택 및 급탕의 보급 정책은 민수용 에너지의 절감 또는 대체의 의미에서 그 필요성 및 당위성을 인정받고 있으나, 다른 대체에너지와 마찬가지로 태양열 이용시스템의 경제성이 가상 문제가 되고 있는 실정이다. 본 연구에서는 태양열 주택 및 급탕의 경제성을 상세히 분석함으로써 실질적인 보급정책 자료를 제공하며, 실수요자를 위한 계몽근거를 마련하고자 한다. 본 연구에서는 태양열 이용시스템의 경제성을 정확히 수행하기 위한 의사결정지원 시스템(decision support system)을 확립시켰으며, 이에 따른 태양열 이용시스템의 열적성능 해석과 동시에 경제성 분석은 시행오차(trial & error)하에 수행할 수 있도록 각종전산 프로그램을 개발하였다. 태양열 주택 및 급탕의 열적성능 해석은 모의실험을 통하여 기상 조건과의 상관관계를 도출하고 태양열 이용시스템의 추가비용 및 연료가 이용을 현재가 (present worth) 개념으로 적응하여 산출하고, 순익분기 해석법 (break-even point analysis method) 및 수명가 산정법(life-cycle cost analysis method)으로 경제성 분식을 중점적으로 수행하였다.

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A Study on the Internal Structure of Heumgyeonggaknu

  • Kim, Sang Hyuk;Lee, Yong Sam;Lee, Min Soo;Ham, Sun Young
    • Journal of Astronomy and Space Sciences
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    • 제30권2호
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    • pp.113-121
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    • 2013
  • Heumgyeonggaknu is a water-hammering type automatic water clock which was made by Jang Yeong-Sil in 1438. The water clock that is located in Heumgyeonggaknu consists of Suho which is equipped with 2-stage overflow. Constant water wheel power is generated by supplying a fixed amount of water of Suho to Sususang, and this power is transferred to each floor at the same time. The 1st floor rotation wheel of Gasan consists of the operation structure which has the shape of umbrella ribs. The 2nd floor rotation wheel is made so that the 12 hour signal, Gyeong-Jeom signal, and Jujeon constitute a systematic configuration. The 3rd floor rotation wheel is made so that the signal and rotation of Ongnyeo and four gods can be accomplished. Based on the above conceptual design, this paper analyzed the internal signal generation and power transmission of Heumgyeonggaknu.