• 한국환경과학회지
• /
• 제1권1호
• /
• pp.47-51
• /
• 1992

수중에 존재하는 휘발성 유기화합물은 샤워를 하는동안 공기로 방출되고 공기농도는 샤워 변수에 따라 달라지는데, 이는 휘발성 유기화합물의 호기농도의 변화를 야기 시킨다. 본 연구에서는 샤워를 하는 동안 공기중의 클로로포픔 노출에 영향을 미치는 주요한 샤워변수(물온다 및 노출시간)를 클로로포픔 호기농도를 측정하여 검토 하였다. 크롤로포름 호기농도는 물의 온도와 노출 시간이 증가함에 따라 증가 하였다. 가장 큰 클로로포름 호기농도 차이를 나타내는 두개의 흡기 노출 조건은 미지근한 물을 이용한 5분 동안의 노출과 더운 물을 이용한 15분 동안의 노출이었다. 클로로포름 호기농도는 후자의 노출후에 전자의 경우보다 거의 3배 정도 높았다. 주요 샤워변수와 수중농도로 조정된 호기농도 사이의 수학모델은 0.0001의 확률에서의 데이타와 훌륭한 일치되는 결과를 나타내었다.

• 상하수도학회지
• /
• 제18권5호
• /
• pp.638-648
• /
• 2004

In many drinking water treatment plants, chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of haloacetic acid (HAAs). In this study, headspace solid-phase microextraction (HS-SPME) was studied as a possible alternative to liquid-liquid extraction for the analysis of HAAs in drinking water. The method involves direct derivatization of the acids to their methyl esters without methyl tert-butyl ether (MTBE) extraction, followed by HS-SPME with a $2cm-50/30{\mu}m$ divinylbenzene/carboxen/polydimethylsiloxane fiber. The effects of experimental parameters such as selection of SPME fiber, the volume of sulphuric acid and methanol, derivatization temperature and time, the addition of salts, extraction temperature and time, and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The $2cm-50/30{\mu}m$-divinylbenzene/carboxen/polydimethylsiloxane fiber, sulphuric acid of 1ml, methanol of 3ml, derivatization temperature of $50^{\circ}C$ derivatization time of 2hrs, sodium chloride salt of 10g, extraction time of 30 minutes, extraction temperature of $20^{\circ}C$ and desorption time of 1 minute at $260^{\circ}C$ were selected as the optimal experimental conditions for the analysis of HAAs. The linearities ($r^2$), relative standard deviations (%RSD) and limits of detection (LOD) for HAAs were 0.9978~0.9991, 1.1~9.8% and $0.05{\sim}0.2{\mu}g/l$, respectively.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.319-322
• /
• 1999

Land surface hydrological conditions have been considered to play an important role in the global and regional climate variability. Especially, snow, soil moisture, surface temperature, vegetation and rain are the key parameters which should be observed in the global scale. In this paper, new algorithms for these land surface hydrological parameters have been developed by introducing frequency and polarization dependencies of these parameters in the microwave radiative-transfer equations. The algorithms were applied to the TRMM Microwave Radiometer. (TMI) and validated by using the ground data obtained in the Tibetan Plateau. The estimated snow, soil moisture, surface temperature, water content of vegetation and rain patterns corresponded reasonably to the observed ones.

• 대한설비공학회지:설비저널
• /
• 제14권4호
• /
• pp.285-292
• /
• 1985

A computer program for thermal design analysis has been developed to predict the performance of an absorption heat transformer. The effects of temperature boost, cooling water temperature and effectiveness of components on the performance were investigated. Not only the detailed thermodynamic states such as temperatures, concentration of the solution, and mass flow rate at each point of the process but also the heat transfer rate in each component could be easily determined with given input parameters. The system's coefficient of performance (COP) was seen to increase with increased effectiveness of components, decreased temperature boost of hot water, and decreased cooling water temperature. Even though the COP increases with increased effectiveness of the components, the variation in the COP is not substantial above certain values of the effectiveness. A reference design point can be selected on this basis.

• 설비공학논문집
• /
• 제17권6호
• /
• pp.521-528
• /
• 2005

This study has been conducted to investigate the potential energy reserve amount of river water as energy resource with useful temperature difference. Since the river water temperature is one of the primary parameters deciding the potential amount of river water energy reserve amount, the climate change effects on it are critically important. In this study, the heat exchange processes and the inter-relationship between the air temperature and river water temperature have been theoretically analyzed. Based on the present study, the potential energy reserve of river water is calculated to amount to 192,000 Tcal/year. Among this, it is estimated that approximately 2,000 Tcal/year can be directly utilized for heat pump energy sources.

• 한국환경과학회지
• /
• 제16권5호
• /
• pp.623-632
• /
• 2007

The objective of this study is analysis of Andong-Dam lake water quality with water quality model. Model parameters of the WASP applied to Lake Andong-Dam were estimated. The methodology is based on grouping water quality constituents and relevant parameters and successively estimating parameters by a trial-and-error procedure. Water qualify system for modeling consisted of BOD, DO, T-N, T-P. The results of water quality modelling using WASP. T-N was maximum affected by K71C(Organic nitrogen mineralization rate) parameter. T-P was maximum affected by K83C(Dissolved organic phosphorus mineralization) parameter, and It did not show a difference almost from the parameter of others and it omitted. BOD was maximum affected by Temperature parameter, it was visible of the reaction due to the KDC(Deoxygenation rate) in afterwords, and it did not show a difference from the parameter of others and it omitted. DO was maximum affect by Temperature parameter, and It did not show a difference almost from the parameter of others and it omitted. The parameter which it presumes from the this study uses a water quality modeling and Actual value and the result with which it compares, error rate the parameter presumption which is appropriate with 1% interior and exterior is investigated, It will reach and it uses and it will be able to apply to the suitable parameter in water quality modelling of the objective area which can be feeded by it becomes.

• 설비공학논문집
• /
• 제18권1호
• /
• pp.31-37
• /
• 2006

The present study has been experimentally investigated the effect of geometric and operating parameters on the two-phase flow distribution of refrigerants in a horizontal T-junction. The operating parameters were the kind of refrigerants (R-22, R- l34a, and R-410A), saturated temperature, and the inlet mass flux and quality. The geometric parameters were the tube diameter and the tube diameter ratio. The measured data of refrigerants were compared with the values predicted using the models developed by several researchers for air/water or steani/water two-phase flow. Among the operating parameters, the inlet Quality was the most sensitive to the mass flow rate ratio. Between the geometric parameters, the tube diameter ratio was more sensitive than tube diameter.

• 동력기계공학회지
• /
• 제15권2호
• /
• pp.25-30
• /
• 2011

A fresh water generation system is designed for converting brackish water or seawater into fresh water. In this paper fresh water generation by distillation process that evaporates feed water and subsequently condenses vapor as evaporation product to get fresh water was studied and city water was employed as feed water. The system uses the ejector to create a vacuum, under which liquid can be evaporated at lower temperature than it at normal or atmospheric condition, hence less energy consumption. The effect of various operating conditions i.e. temperature of feed water and different orifice diameters were studied experimentally to investigate the characteristic of the system. It was found that these parameters have significant effect in the performance of fresh water generation system with low pressure evaporation.

• 한국어병학회지
• /
• 제34권2호
• /
• pp.213-224
• /
• 2021

본 연구는 수온 15, 20 및 25℃에서 조피볼락(Sebastes schlegeli)을 점진적인 저산소 조건에 노출시켜 호흡 대사율이 표준대사율(SMR) 이하로 감소하는 산소포화도, S_crit를 평가하고, 수온별 S_crit 에 4시간 노출 후 혈액 성상의 변화를 조사하기 위하여 실시하였다. 수온 15, 20, 25℃에서 normoxic SMR은 각각 116.5±5.5, 188.6±4.2 및 237.4±6.8 mg O₂/kg/hr이었고, 호흡계수(Q₁₀)는 15-20℃ 구간에서는 2.62, 20-25℃에서는 1.58, 그리고 전 수온 범위의 15-25℃에서는 2.04였다. 수온 15, 20 및 25℃에서 S_crit는 각각 22.1±1.2, 30.6±1.5 및 41.9±1.4 %였다. 수온별 S_crit에 4시간 노출 후 혈액 Ht와 Hb 및 혈장 cortisol, glucose, 전해질(Na⁺, K⁺, Cl^-)과 삼투질 농도는 모든 수온에서 normoxic water의 대조구에 비하여 유의하게 높았다. 수온 15, 20, 25℃의 normoxic water에서는 Ht, Hb 및 혈장 glucose 농도는 15℃에 비하여 20℃와 25℃에서, 혈장 cortisol, 전해질 및 삼투질 농도는 25℃에서 유의하게 높았다. 수온별 S_crit의 저산소에 노출된 조피볼락은 수온이 높을수록 저산소에 의한 어체의 생리적 스트레스는 가중되는 것으로 나타났다.

• Fisheries and Aquatic Sciences
• /
• 제24권7호
• /
• pp.243-259
• /
• 2021

The spatial and temporal behaviors and fluctuations of the cold water that appeared in the South East Sea and the East Sea coast from 2016 to 2017 were investigated. The water temperature drop was large in the east coast from April to June and the southeast coast from July to September, and the temperature drop period was longer in the southeast coast. The water temperature fluctuated sensitively to the wind direction, and it gradually decreased in the southwest wind but rose as if jumping in the northeast wind. Wind stress and surface water temperature had an inverse correlation, which was larger in Bukhang-Idukseo, and decreased toward the north of Guryongpo. The cold water appeared mainly in Geojedo-Pohang after 1 to 2 days when the southwest wind was strong, but when the wind became weak, it shrank to the Idukseo (Ulgi-Gampo) and extended into the open sea in a tongue shape. Cold water was distributed only in Samcheok-Toseong in mid-May, Idukseo-Guryongpo and Hupo-Jukbyeon-Samcheok from late May to mid-July, and Bukhang-Idukseo in August-September. The intensity of cold water was greatest in mid-August, and the center of cold water descended from the east coast to the southeast coast from spring to summer. The water temperature fluctuation was dominant at the periods of 1 d and 7-21 d. In wavelet spectrum analysis of water temperature and wind, wind speed increase-water temperature decrease showed phase difference of 12 h in 2 d, 18 h in 3 d, 1.5 d in 4-8 d, and 2-3 d in 8-24 d period. The correlation between the two parameters was large in Geojedo and Namhang, Bukhang-Idukseo, Guryongpo-Jukbyeon, and Samcheok-Toseong. Monitoring stations with high correlation in all periods were generally parallel to the monsoon direction.