• Title/Summary/Keyword: Combined water

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Current Status of Refractory Dissolved Organic Carbon in the Nakdong River Basin (낙동강유역 난분해성 용존 유기탄소 배출 현황 분석)

  • Lee, Jeonghoon;Kim, Jungsun;Lee, Jae Kwan;Kang, Limseok;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.28 no.4
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    • pp.538-550
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    • 2012
  • This study suggests a general methodology which is designed for assessing RDOC behavior at the catchment scale by coupling properly a series of steam flow and water quality simulation models and actual monitoring data set. The modified TANK model in which a river routing function is incorporated to the conventional one is applied to simulate the long-term daily stream flow data, and the simulated stream flow data is combined with the 7-parameter log-linear model coupled to the minimum variance unbiased estimator to simulate the long-term daily water quality (BOD, COD and TOC) loads. Finally, the regression analysis between the usually monitored water quality data (BOD, COD and TOC) and RDOC is combined with the simulated water quality data to manifest the spatio-temporal variability of RDOC flux behavior at the Korean TMDL catchment scale.

Performance Characteristics of a Combined Regenerative Ammonia-Water Based Power Generation Cycle Using LNG Cold Energy (LNG 냉열을 이용하는 암모니아-물 복합 재생 동력 사이클의 성능 특성)

  • Kim, Kyounghoon;Oh, Jaehyeong;Jeong, Youngguan
    • Journal of Hydrogen and New Energy
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    • v.24 no.6
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    • pp.510-517
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    • 2013
  • The ammonia-water based power generation cycle utilizing liquefied natural gas (LNG) as its heat sink has attracted much attention, since the ammonia-water cycle has many thermodynamic advantages in conversion of low-grade heat source in the form of sensible energy and LNG has a great cold energy. In this paper, we carry out thermodynamic performance analysis of a combined power generation cycle which is consisted of an ammonia-water regenerative Rankine cycle and LNG power generation cycle. LNG is able to condense the ammonia-water mixture at a very low condensing temperature in a heat exchanger, which leads to an increased power output. Based on the thermodynamic models, the effects of the key parameters such as source temperature, ammonia concentration and turbine inlet pressure on the characteristics of system are throughly investigated. The results show that the thermodynamic performance of the ammonia-water power generation cycle can be improved by the LNG cold energy and there exist an optimum ammonia concentration to reach the maximum system net work production.

Estimation of Discharge Load due to Combined Sewer Overflows in the Management of Total Maximum Daily Loads (수질오염총량관리 관거월류부하 변화에 따른 배출부하량 산정방법)

  • Park, Jun Dae;Oh, Seung Young;Choi, Ok Youn
    • Journal of Korean Society on Water Environment
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    • v.27 no.3
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    • pp.293-299
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    • 2011
  • The quantity of a discharge load can change with changes in rainfall in the area with a combined sewer system (CSS). To evaluate the implementation appropriately in the management of total maximum daily loads (TMDLs), the effects of rainfall changes should be considered in the estimation of the discharge load. The rainfall condition for the estimation of the discharge load in a certain year should be standardized to the same rainfall condition as that of the reference year. However, the calculation process is very complicated with its potential limitations. This study investigated and developed relatively simple methods for estimating the discharge load. Load conversion method (LCM) is designed to convert the discharge load under the current rainfall condition into that of the reference rainfall conditions. Simple rainfall data method (SRDM) is to simplify the estimation process of the discharge load by the simple conversion of rainfall data. These methods were applied to calculate the discharge load and examine the estimation results. From the results of this study the application of these methods may be useful for estimating the discharge load in the TMDL process.

Synergistic Effect of Slightly Acidic Electrolyzed Water and Ultrasound at Mild Heat Temperature in Microbial Reduction and Shelf-Life Extension of Fresh-Cut Bell Pepper

  • Luo, Ke;Oh, Deog-Hwan
    • Journal of Microbiology and Biotechnology
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    • v.25 no.9
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    • pp.1502-1509
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    • 2015
  • The objectives of this study were to evaluate the effect of combined treatments (slightly acidic electrolyzed water (SAEW), ultrasound (US), or mild heat (60℃)) on the growth of Listeria monocytogenes and Salmonella enterica serovar Typhimurium in fresh-cut bell pepper, and the shelf-life and sensory quality (color and texture) were followed during storage at 4℃ and 25℃. An additional 0.65, 1.72, and 2.70 log CFU/g reduction was achieved by heat treatments at 60℃ for 1 min for DW, SAEW, and SAEW+US, respectively. Regardless of the type of pathogen, the combined treatment (SAEW+US+60℃) achieved a significantly (p < 0.05) longer lag time in all treatment groups. This combined treatment also prolonged the shelf-life of bell pepper up to 8 days and 30 h for the storage at 4℃ and 25℃, respectively. There was also no significant difference in the color and hardness of treated (SAEW+US+60℃) bell pepper from that of control during the storage. This new hurdle approach is thus expected to improve the microbial safety of bell peppers during storage and distribution.

An Experimental Study of a Water Type Unglazed PV/Thermal Combined Collector Module (액체식 Unglazed PVT 복합모듈의 성능실험연구)

  • Kim, Jin-Hee;Kang, Jun-Gu;Kim, Jun-Tae
    • 한국태양에너지학회:학술대회논문집
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    • 2008.11a
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    • pp.184-189
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    • 2008
  • The excess heat that is generated from PV modules can be removed and converted into useful thermal energy. A photovoltaic/thermal(PVT) module is a combination of photovoltaic module with a solar thermal collector, forming one device that converts solar radiation into electricity and heat simultaneously In general, two types of PVT can be distinguished: glass-covered PVT module, which produces high-temperature heat but has a slightly lower electrical yield, and uncovered PVT module, which produces relatively low-temperature heat but has a somewhat higher electrical performance. In this paper, the experimental performance of water type unglazed PVT combined module, analyzed. The electrical and thermal performance of the module were measured in outdoor conditions, and the results are analyzed. The results showed that the thermal efficiency of the PVT module was 27.05% average and its PV efficiency was about 11.85% average, both depending on solar radiation, inlet water temperature and ambient temperature.

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An Experimental Study of a Water Type Glazed PV/Thermal Combined Collector Module (액체식 Glazed PVT 복합모듈의 성능실험 연구)

  • Kim, Jin-Hee;Kim, Jun-Tae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.4
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    • pp.260-265
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    • 2008
  • The excess heat that is generated from PV modules can be removed and converted into useful thermal energy. A photovoltaic/thermal (PVT) module is a combination of photovoltaic module with a solar thermal collector, forming one device that converts solar radiation into electricity and heat simultaneously. In general, two types of PVT can be distinguished : glass-covered PVT module, which produces high-temperature heat but has a slightly lower electrical yield, and uncovered PVT module, which produces relatively low-temperature heat but has a somewhat higher electrical performance. In this paper, the experimental performance of water type PVT combined module, glass-covered, analyzed. The electrical and thermal performance of the module were measured in outdoor conditions, and the results are analyzed. The results showed that the thermal efficiency of the PVT module was 27.6% average and its PV efficiency was about 10.0% average, both depending on solar radiation, inlet water temperature and ambient temperature.

Study on Antitumor Activity of Water Extract of Omija(Schizandra chinensis Baillon) (오미자 물추출물의 항종양 활성에 대한 효과)

  • 이정숙;이성우
    • Journal of the East Asian Society of Dietary Life
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    • v.2 no.1
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    • pp.103-107
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    • 1992
  • The antitumor activity of Omija water extract on sarcoma 180 transplanted intraperitoneal administration in ICR mice was investigated. combined treatment with Omija water extract and Cyclophosphamide augmented antivity against the solid form of Sarcoma 180 in ICR mice.

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Fast Analytical Method of PCDD/Fs in Water by Combination of Disk Type Solid Phase Extraction and Column Coupling Chromatography (디스크타입 고상추출장치 및 컬럼커플링을 이용한 물시료의 PCDD/Fs 간이분석법)

  • Choi, Jae-won;Moon, Bu-shik;Kim, Kyoung-sim;Kim, Jung-hee;Kim, Sun-heong;Baek, Kyung-hee
    • Journal of Korean Society on Water Environment
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    • v.22 no.5
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    • pp.879-886
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    • 2006
  • The analytical methods of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) for water sample with extremely low concentration was developed to extract large volume and to improve fast chromatography for clean up. Semi-automated solid phase extraction (SPE) system and column coupling chromatography using elution pump was optimized and applied to each processes of treatment plant. Results of disk type SPE indicated that this system was applicable below 40 L of aqueous sample with a flow rate of 0.08 ~ 0.2 L/min. Average recoveries of SPE using labeled sampling spike of $^{37}Cl$-2,3,7,8-TCDD was 97%. Column coupling method resulted in reduced clean up time, solvent volume, increased average recoveries with constant elution rate. The combined methods were applied to the monitoring of drinking water treatment plant. Limits of detection (LOD) of each process were calculated. For example, LOD of raw and treated water ranged 0.094~0.968 pg/L and 0.028~0.364 pg/L, respectively. Combined methods of extraction and cleanup techniques provided fast analysis of PCDD/Fs with high accuracy and low LODs for water samples.