• The Korean Journal of Malacology
• /
• v.14 no.1
• /
• pp.51-59
• /
• 1998

담수산 이매패류인 참재？, Corbicula leana를 대상으로 크기와 수온별로 카드뮴, 구리 및 수은 등의 중금속에 노출시켜 반수치사농도, 호흡률 및 여수율 등의 생리적 내성에 관하여 알아보았다. 17%C에서 작은 개체rnhr,-LC$^{50}$ 은 수은이 1.63 ppm이었으며, 카드뮴과 구리는 각각 7.45및 8.71 ppm으로서 수은에 비해 상당히 높은 값을 나타내었다. 큰 개체구의 경우는 수은이 2.62ppm이었으며, 카드뮴과 구리가 각각10.15와 10.20 ppm이었다. 22$^{\circ}C$의 경우 작은 개체구의 96 hr-LC$^{50}$ ppm은 카드뮴, 구리 및 수은이 각각 5.94, 7.08및 1.63 ppm이었으며, 큰 개체구에서는 각각 8.29, 8.35, 1.87ppm으로서 두수온구에서 모두 작은 개체구에서 중금속 오염원에 의한 영향이 컸으며, 독성순위는 수은>카드뮴>구리 순이었다. 한편 중금속 오염원에 노출시킨 참재첩의 수온-개체크기별 산소소비율과 여수율은 오염원의 농도증가에 따라 고수온에서 영향을 많이 받았으며, 특히 수은의 경우, 22%C-작은 개체구에서 호흡률이 50.7%, 여수율이 52.15%감소되고 있어 여수율이 보다 크게 영향을 받았다.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.1
• /
• pp.106-113
• /
• 2023

The supply of microbiological risk-free water is essential to keep food safety and public hygiene. And removal, inactivation, and destruction of microorganisms in drinking water are key for ensuring safety in the food industry. Ultraviolet-C (UV-C) irradiation is an attractive method for efficient disinfection of water without generating toxicity and adversely affecting human health. In this study, the disinfection efficiencies of UV-C irradiation on Shigella flexneri (Gram negative) and Listeria monocytogenes (Gram positive) at various concentrations in drinking water were evaluated using a water purifier. Their morphological and physiological characteristics after UV-C irradiation were observed using fluorescence microscopy and flow cytometry combined with live/dead staining. UV-C irradiation (254 nm wavelength, irradiation dose: 40 mJ/cm²) at a water flow velocity of 3.4 L/min showed disinfection ability on both bacteria up to 10⁸ CFU/4 L. And flow cytometric analysis showed different physiological shift between S. flexneri and L. monocytogenes after UV-C irradiation, but no significant shift of morphology in both bacteria. In addition, each bacterium revealed different characteristics with time-course observation after UV-C irradiation: L. monocytogenes dramatically changed its physiological feature and seemed to reach maximum damage at 4 h and then recovered, whereas S. flexneri seemed to gradually die over time. This study revealed that UV-C irradiation of water purifiers is effective in disinfecting microbial contaminants in drinking water and provides basic information on bacterial features/responses after UV-C irradiation.

• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.264-269
• /
• 2000

As a part of the ongoing effort towards commercial application of high-temperature fuel cell power generation systems, we have recently built a pilot-scale molten carbonate fuel cell power plant and tested it. The stack test system is composed of diverse peripheral units such as reformer, pre-heater, water purifier, electrical loader, gas supplier, and recycling systems. The stack itself was made of 40cells of $6000cm^2$ area each. The stack showed an output higher than 25kW power and a reliable performance at atmospheric operation. A pressurized performance was also tested, and it turned out the cell performance increased though a few cells have shown a symptom of gas crossover. The pressurized operation characteristics could be analyzed with numerical computation results of a stack model.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2012.04a
• /
• pp.167-169
• /
• 2012

본 연구는 정수기 화재의 원인 판정을 위한 지식기반을 구축하기 위해서 인위적 착화가 발생했을 때의 연소 확산 패턴을 해석하였다. 실험이 재현되는 동안 외부에서 인위적인 에너지의 공급은 없었으며, 정수기는 정상 작동 상태를 유지시켰다. 인위적 화염으로 착화되어 50[sec] 경과하였을 때까지 불꽃은 외부에서 관측되지 않았다. 그러나 120[sec] 정도 경과되었을 때 일순간 화염은 확산되기 시작하였으며, 부분적인 소락이 발생되는 것이 관측된다. 화염이 180[sec] 동안 진행되었을 때 강제로 진압된 후 연소패턴 분석에서 최초의 착화점을 기준으로 정확한 브이패턴(V-pattern)이 형성되었으며, 외부에서 화염이 공격되었을 때와 확연한 차이가 있음을 알 수 있다. 또한 정수기 후면에 설치된 방열판의 열화 특성 분석에서 화열의 공격방향 판정이 가능한 것을 알 수 있었다.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.687-689
• /
• 2000

Molten Carbonate Fuel Cell (MCFC) with high electrical efficiency and low environmental effect has been developed for the commercial application of power generation fields. Recently we have built a 25 kW molten carbonate fuel cell power generation system and tested it. The MCFC system is composed of diverse peripheral units such as reformer, pre-heater, water purifier. electrical loader, gas supplier, and recycling systems. The stack itself was made of 40 cells of $6.000 cm^2$ area each. The stack showed an output of 28.6 kW power and a reliable performance at atmospheric operation. while in pressurized operation the stack showed an output 25.6 kW lower than the atmospheric operation. The reason of lower performance of pressurized operation was caused from a gas cross over shown in few cells in the stack.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.1
• /
• pp.73-82
• /
• 2002

A small refrigeration system used in a water purifier was tested by employing propane/isobutane (R-290/R-6OOa) mixtures as an alternative refrigerant of R-12. The drop-in tests were performed by varying mass fraction of propane at 0.25, 0.5 and 0.75 with a change of both refrigerant charge amount and capillary tube length in order to find an optimum composition in aspect of performance and reliability of the system. As a result, the mixture of 50% propane-50% isobutane showed the best performance and reliability among them in a small refrigeration system. During steady state operations, both the COP and refrigeration capacity increased by 4% and 9%, respectively, as compared to the baseline R-12 system. In addition, the propane/isobutane (50/50) mixture system yielded advantages in the minimization of modification and redesigning of system components due to very similar saturation tempera- ture and pressure characteristics with R-12.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.429-432
• /
• 2000

본 논문의 정수기는 영동산 일라이트를 필터의 주된 재료로 사용하였다. 구조는 여과필터를 교체하여 사용할 수 있도록 된 정수기의 필터 케이스 및 여과 방법에 관한 것으로써, 보다 상세하게는 필터 케이스가 분리, 결합이 간편한 본체와 마개로 구성되어 있다. 이 본체는 1차 여과부와 2차 여과부로 분리되어 물이 1차 여과부의 상부를 통해 인입되어 2차 여과부의 상부로 연결되도록 되어 있어 동일한 크기 내에서 여과구간이 2배로 길어져 여과 효율이 우수한 동시에 물인입구와 물배출구가 동일한 방향에 위치하여 다수 개의 필터 케이스를 연결할 때 필터 케이스의 간격을 좁힐 수 있어 필터 케이스의 설치면적이 좁다. 본체와 마개의 체결방식은 볼트 체결방식으로 되어 있으며, 마개는 플라스틱 재질이어서 본체에 마개를 단단히 체결하면 누수가 방지되도록 되어있다. 즉, 정수기의 필터하우징 성능과 영동산 일라이트가 가지고 있는 기능성을 이용한 필터를 사용함으로써 정수기에서 요구되어지는 정수능력을 가진 정수기를 개발 보고한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.11a
• /
• pp.1139-1141
• /
• 2011

기존의 산업용 컨트롤러로 많이 사용되는 프로그래머블 로직 컨트롤러(PLC)를 사용할시 고비용과 큰 부피로 인해 정수기를 소형으로 만들기 어렵다. 따라서 본 가정용 정수기는 소형 MCU 사용과 동시에 정수기에 최적화된 PCB를 제작하여 정수기를 소형화 하였다. 재 프로그램 가능한 MCU 채택으로 추후 시스템이 변경되거나, 프로그램에 보완사항이 필요할 경우 손쉽게 업그레이드가 가능하도록 설계하였다.

• Membrane Journal
• /
• v.32 no.2
• /
• pp.126-132
• /
• 2022

Water purifiers have a quite different characteristic in comparison with general membrane water treatment processes in which the running and resting are repeated dozens of times a day. In the case of water purifiers using reverse osmosis membranes, this characteristic makes a phenomenon that the total dissolved solids (TDS) of permeate in water purifiers at the beginning of running shows a higher value than a normal value (TDS reduction is lower than a normal value). It is called "TDS creep". The effects of resting times and feed concentrations on the TDS creep were investigated. The feed flushing, the volume increase in permeate side and the flushing with purified water were applied to reduce TDS creep and the effectiveness were observed. Among these trials, the minimization of concentration between feed and permeate side of reverse osmosis membrane like the flushing with purified water can be an ultimate solution to reduce the TDS creep.

• Journal of the Korean Ceramic Society
• /
• v.53 no.1
• /
• pp.1-6
• /
• 2016

In this year, Koreans have a shortage in agricultural and drinking water due to severe algal blooms generated in major lakes. Waste oyster shells were obtained from temporary storage near the workplace at which oysters were separated from their shells. Heating ($1000^{\circ}C$ for 1 h in air) was employed to convert raw oyster shell powders into calcium oxide powders that reacted efficiently with phosphorus and nitrogen to remove algal blooms from eutrophicated wastewater. As the dispersed amount of heated oyster shell powders was increased, water clarity and visual light penetration were improved. Coagulation, precipitation and carbonation process of the heated oyster shell powders in a water purifier facilitated removal of eutrophication nutrient such as phosphorus and nitrogen, which is both beneficial and economically viable. $CO_2$ implantation by carbonation treatment not only produced thermodynamically stable CaO in oyster shells to derive precipitated calcium carbonate (PCC) but also accelerated algal removal by activation of coagulation and precipitation process. The use of oyster shell powders led to a mean reduction of 97% in total phosphate (T-P), a mean reduction of 91% in total nitrogen (T-N) and a maximum reduction of 51% in chemical oxygen demand (COD), compared with the total pollutant load of raw algal solution. Remarkable water quality improvement of algal removal by heated oyster shell powders and PCC carbonation treatment will allow utilization as water resources to agricultural or industrial use.