• Transactions of the Korean hydrogen and new energy society
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• v.18 no.2
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• pp.151-156
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• 2007

Solar cell and nanofiltration membrane were utilized in a system of enzymatic hydrogen production through light-sensitized photoanode, which resembles photoelectrochemical(PEC) configuration. Solar cell uses no additional light energy to increase energy for electrons to reduce protons and for holes to oxidize water to oxygen, and nanofiltration membrane replaces a salt bridge successfully with increased ion transport capability. With this system configuration, optimized amount of enzyme(10.98 unit), and an anodized tubular $TiO_2$ electrode($5^{\circ}C$/1 hr in 0.5 wt% HF-$650^{\circ}C$/5 hr) hydrogen evolved at a rate of ca. $43\;{\mu}mol/(cm^2{\times}hr)$ in a cathodic compartment and oxygen generated at a rate of ca. $20\;{\mu}mol/(cm^2{\times}hr)$ in an anodic compartment. The stoichiometric evolution of gases indicated that water was splitted in the system.

• International Journal of Air-Conditioning and Refrigeration
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• v.12 no.1
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• pp.30-36
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• 2004

The present study investigates the fire suppression characteristics using a water mist fire suppression system. Numerical simulations of fire suppression with water mist are performed with considering the interaction of fire plume and water spray. The predicted temperature fields of smoke layer are compared with those of measured data. Numerical results agree with the experimental results within $10^{\circ}C$ in the case without water mist. In the case of fire suppression with water mist, numerical results do not predict well for temperature field in the gradual cooling region after water mist injection. But the predicted results of initial fire suppression are in good agreement with those of measured data. The reason for the discrepancy between predicted and measured data is due to the poor combustion modeling during the injection of water mist. More elaborate models for numerical simulation are required for better predictions of the fire suppression characteristics using water mist.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.261-267
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• 2003

The present study investigates the fire suppression characteristics using a water mist fire suppression system. Numerical simulations of fire suppression with water mist are performed with considering the interaction of fire plume and water droplet, droplet evaporation, and combustion of pool fire. The predicted temperature fields of smoke layer are compared with that of measured data. Numerical results agree with the experimental results within 5$^{\circ}C$ in the case without water mist In the case of fire suppression with water mist, numerical results dose not predict well lot temperature field in the gradual cooling region after water mist injection. But the predicted results of initial fire suppression are in good agreement with that of measured data. The reason of the discrepancy between predicted and measured data is due to the variation of turning rate during the injection of water mist. The effect of burning rate on the fire suppression is left as future study.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.7
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• pp.269-274
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• 2016

This paper aims to suggest the water curtain installation guideline for prevention of fire spread. The water curtain systems play a role in preventing fire spread which is caused by fire flames and radiation heat release from a fire source. The radiation attenuation ratio is affected by the water droplet size, vertical distance from the nozzle and flow rate. This study suggests the water curtain installation guideline as follows : (1) Investigation of a reference store array (2) Calculation of the number of drencher heads (3) Review of the relationship between droplet size and attenuation factor depending on the height of the drencher head (4) Review of a drencher head array and spray overlapping. The reference traditional market in which a fire compartment is installed using a water curtain can be predicted to have a radiation attenuation ratio of 50%.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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• pp.338-347
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• 2005

Horizontal-Flow Roughing Filtration (HRF) is one of altemative pretreatment methods e.g. prior to Slow Sand Filtration (SSF). However, some of its limitations are that the effluent quality drops drastically at higher turbidity (>200 NTU) and at higher filtration rate (>1 m/h). To overcome these drawbacks, we suggested Direct Horizontal-Flow Roughing Filtration (DHRF), which is a modified system of Horizontal-Flow Roughing (HRF) by addition of low dose of coagulant prior to filtration. In this study to optimize the DHRF configuration, a conceptual and mathematical model for the coarse compartment has been developed in analogy with multi-plate settlers. Data from simple column settling test can be used in the model to predict the filter performance. Furthermore, the model developed herein has been validated by successive experiments carried out. The conventional column settling test has been found to be an handy and useful to predict the performance of DHRF for different raw water characteristics (e.g. coagulated or uncoagulated water, different presence of organic matter, etc.) and different inital process conditions (e.g. coagulant dose, mixing time and intensity, etc.). An optimum filter design for the coarse compartment (grain size 20mm) has been found to be of 3 m/h filtration rate with filter length of 4-4.5 m.

• Journal of Radiation Protection and Research
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• v.8 no.2
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• pp.8-14
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• 1983

The doses to Korean adult by a single and chronic intake of tritiated water are determined using a three compartment model, which describes the retention of tritium radionuclide in body water and in bound organic form in the body. The results show that the total dose of a single intake, using retention half-time for the three-compartment of 9, 30, and 450 days, is 17.64 mrads ($176.4{\mu}Gy$) per 1mCi/kg ($3.7{\times}10^7Bq/kg$) intake, 97% of which is due to tritium in body water and 3% to bound tritium in tissue. In the chronic intake of 1mCi/day($3.7{\times}10^7Bq/day$) tritiated water, the total dose is 85.5 mrad/day(0.855mGy/day). Furthermore, in this study (MPC) a and (MPC)w values of tritium for Korean man are calculated by using the modified formula originated from ICRP Publication-2. From the results, we found that the (MPC) a, w values of ICRP underestimated approximately 50%, the (MPC)a, w values of Korean man must be elevated as high as approximately 50% than that of ICRP.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.3
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• pp.367-373
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• 2003

The present study investigates the fire suppression characteristics using a water mist fire suppression system. The fire extinguishing times are measured for various fire sources, fuel types, and different total flooding rates of water mist. Pool fire with hydrocabon fuel is successfully extinguished within a minute under the operating conditions of the water mist system. Two different regimes of the smoke layer cooling are observed, such as rapid and slow cooling processes. The regimes are divided by threshold time which is calculated with auto-correlation function. The threshold time for the initial cooling decreases with increasing water flow-rates and fire sources. These initial cooling effects play an important role in preventing the occurance of flashover fire by the initial fire suppression.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.169-175
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• 2009

Microbial fuel cell (MFC) is a device to produce a electricity from the oxidation of organic materials using microorganism. Recently many researchers have been studying MFC which is focused as regeneration energy source. Previews studies have focused every each factor that influence the production of electric power. However they didn't study a lot about the correlation among the factors. In order to improve the MFC, we analysed the factors which influencing the generation of electric power of MFC. Also, we made a new compartment to verify the correlations among the factors efficiently. Based on the result obtained from the experiments in the laboratory, we analysed the factors and we suggested a new concept of waste water treatment system to produce electrical energy during the treatment of waste water.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.127-131
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• 1999

Anaerobically grown cells of an Fe(III)-reducing bacterium, Shewanella putrefaciens IR-l, were electrochemically active with an apparent reduction potential of about 0.15 V against a saturated calomel electrode in the cyclic voltammetry. The bacterium did not grow fermentatively on lactate, but grew in an anode compartment of a three-electrode electrochemical cell using lactate as an electron donor and the electrode as the electron acceptor. This property was shared by a large number of Fe(III)-reducing bacterial isolates. This is the first observation of a direct electrochemical reaction by an intact bacterial cell, which is believed to be possible due to the electron carrier(s) located at the cell surface involved in the reduction of the natural water insoluble electron acceptor, Fe(III).

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.132-133
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• 2005

A study to evaluate the fire extinguishing performance of the water mist system inside simulated machinery spaces according to IMO MSC/Circ.668 was performed. Fire tests were conducted inside a compartment having a area 100$m^2$(10m${\times}$10m) with a ceiling height of 10m and door opening of 2m${\times}$2m in size. Test fuels were used heptane, diesel, wood crib and mineral oil. Water mist nozzles were installed downward at ceiling and horizontally at bilge area. All fires in the test were extinguished within 15minutes of system activation and there was no reignition or fire spread.