• Membrane and Water Treatment
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• 제2권1호
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• pp.1-24
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• 2011

The deficiency of clean water is a major global concern because all the living creatures rely on the drinkable water for survival. On top of this, abundant of clean water supply is also necessary for household, metropolitan inhabitants, industry, and agriculture. Among many purification processes, advances in low-energy membrane separation technology appear to be the most effective solution for water crisis because membranes have been widely recognized as one of the most direct and feasible approaches for clean water production. The aim of this article is to give an overview of (1) two new emerging membrane technologies for water reuse and desalination by forward osmosis (FO) and membrane distillation (MD), and (2) the molecular engineering and development of highly permeable hollow fiber membranes, with polyvinylidene fluoride (PVDF) and polybenzimidazole (PBI) as the main focuses for the aforementioned applications in National University of Singapore (NUS). This article presents the main results of membrane module design, separation performance, membrane characteristics, chemical modification and spinning conditions to produce novel hollow fiber membranes for FO and MD applications. As two potential solutions, MD and FO may be synergistically combined to form a hybrid system as a sustainable alternative technology for fresh water production.

• 한국물환경학회지
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• 제33권3호
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• pp.359-369
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• 2017

Water distribution systems supply drinking water to consumers' taps. Internal corrosion of metallic pipe used in drinking water distribution systems has reduced water quality and led to increased levels of toxic heavy metals such as lead, copper and nickel. These problems have been experienced to varying degrees by water utilities in many countries. North America has successfully managed and controlled pipe corrosion and corrosive water in water distribution system based on various policies, regulations and rules. Practical and engineering guidelines for evaluation of pipe corrosion and determination of treatment options are also provided to assist drinking water supplies. In addition, the corrosion mechanism in water distribution systems, such as the complex effects of physical and chemical parameters on the corrosion pipes has been improved to accurately predict corrosion rates of metallic pipes in actual water distribution systems. This paper reviews various regulations, policy statement, and treatment produces on controlling corrosion in drinking water distribution systems in US and Canada and then offers suggestion for management of corrosive water and pipe corrosion in drinking water distribution system in Korea.

• 한국수소및신에너지학회논문집
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• 제27권5호
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• pp.571-580
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• 2016

In this paper, performance of the gas turbine combined cycle(GTCC) using pre-combustion carbon capture technology was comparatively analysed. Steam reforming and autothermal reforming were used. In the latter, two different methods were adopted to supply oxygen for the reforming process. One is to extract air form gas turbine compressor (air blowing) and the other is to supply oxygen directly from air separation unit ($O_2$ blowing). To separate $CO_2$ from the reformed gas, the chemical absorption system using MEA solution was used. The net cycle efficiency of the system adopting $O_2$ blown autothermal reforming was higher than the other two systems. The system using air blown autothermal reforming exhibited the largest net cycle power output. In addition to the performance analysis, the influence of fuel reforming and carbon capture on the operating condition of the gas turbine and the necessity of turbine re-design were investigated.

• 대한환경공학회지
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• 제36권8호
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• pp.579-587
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• 2014

수계에서 검출되는 미량유해물질의 빈도와 종류가 다양해지고 있다. 따라서 정수처리시스템에서 고려되어야 할 부분으로 거론되고 있으며 제거공정과 처리효율에 대한 연구가 활발하게 진행되고 있다. 본 연구에서는 고도처리공정과 나노여과공정을 이용한 제거효율을 평가하였다. 나노여과공정의 경우 물질의 물리화학적 특성에 따라 제거율이 상이하게 나타났다. 물질의 분획분자량이 제거율이 가장 큰 영향을 미치는 것으로 확인되었다. 또한, 원수의 pH보다 높은 pKa 값을 갖거나 Log Kow 값이 2 이하인 물질의 제거효율이 감소되었다. 고도처리공정 중 산화공정에서는 대상물질의 분자량이 클수록 그리고 소수성을 띌수록 산화반응에 의한 제거효율이 감소되었다. 흡착공정에서는 산화되지 않은 대부분의 물질이 제거되었으며 $H_2O_2$에 의하여 산화가 더 잘 진행될수록 흡착반응이 향상되었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.561-564
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• 2007

FCEV uses electric energy which generated from the reaction between Hydrogen and Oxygen in fuel cell stack as driving force. As fossil fuels are exhausted, fuel cell is regarded as a potent substitute for next generation energy source, and thus, most of car-makers make every efforts to develop fuel cell electric vehicle (FCEV). In addition, fuel cell is also beneficial in aspect of environment, because only clean water is produced during chemical reaction process instead of harmful exhausted gas. Generally, Hydrogen is supplied from high-pressured fuel tank, and air blower (or compressor) supply Oxygen by pressurizing ambient air. Air blower which is driven by high speed motor consumes about $7{\sim}8$ % of energy generated from fuel cell stack. Therefore, the efficiency of an air blower is directly linked with the performance of FCEV. This study will present the development process of an air blower and its consisting parts respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1837-1839
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• 2003

Recently deep interests have been paid on the effective generation of ozone, which has been widely used for water treatment, deoderization, color removal and chemical processing of exhausted smoke. The silent discharge reaction has been proposed as the most effective in the many ozone generation methods by electric discharge, because silent discharge excel others in the condition of high ozone generation yield and low power consumption. In this paper, ozone water generated system measure with silent discharge characteristics and pulsed power supply.

• 한국농공학회논문집
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• 제64권5호
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• pp.1-8
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• 2022

Hydrogen can be produced by gasification of biomass and other combustible fuels. Depending on oxydant agents, syngas or producer gas compositions become quite different. Since biomass has limited amount of hydrogen including moisture in it, the hydrogen concentration in the syngas is about 15% when air is supplied for oxidant agent. Experiments were conducted to investigate the channges in hydrogen concentrations in syngas with different oxidant agent conditions, fuel conditions, and external heat supply. Allothermal reaction resulted in higher concentrations of hydrogen with the supply of steam over air, reaching over 60%. Hydrogen is produced by water-gas and water-gas shift reactions. These reactions are endothermic and require enough heat. Autothermal reaction occurred in the downdraft gasifier used in the experiment did not provide enough heat in the reactions for hydrogen production. Steam seems a more desirable oxidant agent in producing the syngas with higher concentrations of hydrogen from biomass gasifications since nitrogen is included in syngas when air is used.

• 한국산업보건학회지
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• 제21권1호
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• pp.40-48
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• 2011

This study was intended to resolve problems caused by different classification criteria and management methods of carcinogenicity, which have made industrial safety & health institutions and business employers difficult to execute projects or to carry out occupational safety and health related works, and have affected how civic groups perceive carcinogens. The content of this study contained the comparison of management and categorization standards for carcinogens between Korea and other countries as well as the current carcinogenicity-related information supply status of each professional institution. Furthermore, this research examined the current state of supplying information on carcinogenicity among major institutional information supply according to the categorization standard for carcinogens by UN GHS, Ministry of Employment and Labor in Korea(KMoEL), and GHS MSDS provided by Korea Occupational Safety & Health Agency(KOSHA). Now, professional agency provide 927 kinds of IARC, 237 kinds of NTP, 351 kinds of ACGIH and 1,006 kinds of EU ECHA information on carcinogenic agents. KMoEL provides carcinogenicity-related information of 58 chemical agents in accordance with the category of carcinogens guided by ACGIH. KOSHA offers 13,232 kinds of GHS MSDS information including 2,484 carcinogenic substances. Therefore, carcinogenicity-related information of chemical substances, which are not available on the existing GHS MSDS DB, should be updated for the future reference.

• 한국환경과학회지
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• 제14권9호
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• pp.835-842
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• 2005

The three-dimensional eco-hydrodynamic model was applied to estimate the physical process in terms of COD (chemical oxygen demand) and net supply(or decomposition) rate of COD in Kamak Bay to find proper management plan for oxygen demanding organic matters. The estimation results of the physical process in terms of COD showed that transportation of COD is dominant in surface level while accumulation of COD is dominant in bottom level. In the case of surface level, the net supply rate of COD was 0 -0.50 mg/m2/day. The net decomposition rate of COD was 0 -0.04 mg/m2/day in middle level(3 -6m) and 0.05 -0.1 5 mg/m2/day in bottom level(6m -bottom). These results indicates that the biological decomposition and physical accumulation of COD are occurred predominantly at the northern part of bottom level. Therefore, it is important to consider both allochthonous and autochthonous oxygen demanding organic matters in the region.

• 한국환경보건학회지
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• 제9권1호
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• pp.77-84
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• 1983

A study was carried out to find drinking water qualities of 56 simple piped water supply systems and 37 water pumps in Chun Sung Conutry, Kang Won Province from 1st July to 30th August 1981. 1. The results of all kinds of water test are found to be safe at only one out of fifty six samples of simple piped water supply system at two out of thirty-seven samples of water pump and unsafe at the others. 2. In general Count of Bacteria test, twelve (21.4%) out of fifty six samples of the simple piped water are found to be safe for the legitimate standard of safty water, and five (13.5%) out of thirty=seven samples of pump water. 3. Escherichia coli group is negative at seven (12.5%) out of fifty-six samples of simple piped water, and eight (21.6%) out of thirty-seven samples of pump water. 4. The results of the physical and chemical examination of drinking water specimen are found to be safe at twelve out of fifty-six samples of simple piped water and at twenty-eight out of thirty-seven samples of pump water.