• Archives of design research
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• v.18 no.3 s.61
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• pp.219-222
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• 2005

This study is for the design developement of wall mount air purification device used for pleasant and clean resident environment. As more people have the high standard of living, they are interested in the air quality of indoor environment, since it is believed its relationship with human health. Now the social demand of air purifier is increasing. Its market is growing and there are various design products in the market. However, dominant current products are floor-based standing type, it needs much spaces to install for the air inhalation and exhaust. Therefore, this product provides the space-saved design. Its concept comes from existing wall mount type air conditioners. The effect of wall decoration is another merit of this proposal. It has an easy filtering change and cleaning system and a simple operation of multiple functions. This product also has the perfect-matched slim design that is consist of natural curves with rectangle for any indoor spaces.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.874-882
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• 2019

In this study, the gasification characteristics of four types of unused woody biomass and one waste wood in a lab-scale bubbling fluidized bed gasifier (Diameter: 0.11 m, Height: 0.42 m) were investigated. Effect of equivalence ratio (ER) of 0.15-0.3 and gas velocity of $2.5-5U_0/U_{mf}$ are determined at the constant temperature of $800^{\circ}C$ and fuel feeding rate of 1 kg/h. The silica sand particle having an average particle size of $287{\mu}m$ and olivine with an average particle size of $500{\mu}m$ were used as the bed material, respectively. The average product gas composition of samples is as follows; $H_2$ 3-4 vol.%, CO 15-16 vol.%, $CH_4$ 4 vol.% and $CO_2$ 18-19 vol.% with a lower heating value (LHV) of $1193-1301kcal/Nm^3$ and higher heating value (HHV) of $1262-1377kcal/Nm^3$. In addition, it was found that olivine reduced most of C2 components and increased $H_2$ content compared to silica sand, resulting in cracking reaction of tar. The non-condensable tar decreases by 72% ($1.24{\rightarrow}0.35g/Nm^3$) and the condensable tar decreases by 27% ($4.4{\rightarrow}3.2g/Nm^3$).

• Clean Technology
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• v.4 no.2
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• pp.23-31
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• 1998

Photo-sensitized oxidation of benzene in aqueous solution was conducted with persulfate, nitrate, nitrite, sulfate and chloride as sensitizers.In the photo-sensitized oxidation of benzene persulfate, nitrate and nitrite could act as sensitizers, while no detectable effects could be observed with sulfate and chloride. With increasing nitrite concentration the photo-sensitized oxidation of benzene ran through a maximum value and decreased thereafter with increasing nitrite concentration. A build-up of nitrite ions seemed to scavenge hydroxyl radicals. When nitrite was present with other ions, nitrite inhibited the photo-sensitized oxidation of benzene. Phenol and biphenyl were identified as intermediate.

• Clean Technology
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• v.16 no.1
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• pp.64-70
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• 2010

In this study, we suggest the application of the divided-wall column (DWC) to the existing trichlorosilane(TCS) purification process in the commercial polysilicon manufacturing process. Using Aspen HYSYS V7.1, an extensive simulation study was carried out for the analysis of the energy consumptions and capital cost for the conventional sequential distillation configuration and the DWC for producing a given purity and yield of trichlorosilane. As a result, it is shown that the DWC saves the separation energy by 61% and the equipment cost by 58% compared with the conventional distillation process.

• Clean Technology
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• v.16 no.4
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• pp.254-257
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• 2010

[ $Mg(OH)_2$ ]slurry was prepared by using natural mineral brucite exploited from Liaoning province in China, and its de-SOx efficiency was examined. The effect of difference in particle size distribution of brucite and activation by hydrothermal treatment were investigated. The de-$SO_2$ efficiency of a finely-milled brucite sample below 1000 mesh with narrow particle size distribution was higher than that of the sample below 80 mesh. On the other hand, the de-$SO_2$ efficiency of brucite sample below 80 meshes was significantly improved by the hydrothermal treatment at 363 K tor 3 h.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.89-96
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• 2011

The objective of this study is to evaluate reduction efficiency of various air purifiers on airborne microorganism causing air infected animal disease according to sample collection method. Collection efficiencies of MS2 virus and Pseudomonas fluorescens by biosampler was significantly higher than those by button sampler (p<0.05). Regardless of types of air purifier and sample collection method, temporal reduction efficiencies of MS2 virus and P. fluorescens compared to initial background concentration were >50% and >45% on 5 minutes, >70% and >50% on 15 minutes, >80% and >70% on 30 minutes and >90% and >75% on 60 minutes after operating air purifier, respectively. The air purifier of ionizer type showed the highest reduction efficiency on MS2 virus followed by air purifier of electronic precipitation, water filter and dry filter while the reduction efficiency of air purifier on P. fluorescens was highest in the electronic precipitation type followed by ionizer type, dry filter type and water filter type (p<0.05). Based on the results obtained from this study, temporal reduction efficiency of air purifier on MS2 virus was relatively higher than P. fluorescens.

• Clean Technology
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• v.30 no.2
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• pp.71-93
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• 2024

Recently, the establishment of a hydrogen-based economy and the utilization of low-carbon energy sources, particularly for shipping and power generation, have been in high demand in order to achieve carbon neutrality by 2050. In particular, ammonia is gaining renewed attention because it is capable of serving as a key facilitator for high-efficiency green hydrogen storage and transportation and it is also capable of serving as a low-carbon energy source. Although ammonia can be synthesized through the Haber-Bosch process, the high energy consumption and carbon emissions associated with this process result in minimal carbon reduction. To address the critical drawbacks of the traditional Haber-Bosch process, various thermochemical synthesis methods have been developed recently, allowing for the synthesis of ammonia with lower carbon emissions and a higher energy efficiency. Research is also progressing in the development of high-performance catalyst materials that are capable of demonstrating sufficient ammonia synthesis performance under milder process conditions compared to conventional methods. Additionally, a variety of different processes such as chemical-looping ammonia synthesis, plasma synthesis, and mechanochemical synthesis are being applied diversely. This review aims to provide a detailed overview of the emerging ammonia synthesis technologies that have been developed to effectively store green hydrogen for future applications.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.139-142
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• 2001

서울시 대도시 지하수의 수리지구화학 및 오염 특성을 토지 이용 특성(청정지역, 주거지역, 농업지역, 교통혼잡지역, 공단지역)과 관련하여 고찰함으로써 대도시 지하수 수질의 효율적 관리에 활용하기 위한 3개년 모니터링 연구를 수행하고 있다. 본 논문에서는 현재까지의 연구 결과를 요약하여 소개한다. 총용존고체 함량(TDS)은 지하수 수질 특성 파악에 손쉽고 효과적으로 활용할 수 있는 파라미터임이 확인되며, 청정지역, 주거지역, 농업지역, 교통혼잡지역, 공단지역의 순으로 증가하는 경향이 뚜렷하다. 따라서, 서울 도시 지하수 수질은 일차적으로 부근의 도시화 특성과 밀접한 상관성을 가짐을 확인하였다. 한편, 청정지역의 수질 특성 자료를 제시하여 지하수 오염도 평가의 기준(배경 수질) 자료로 활용토록 하였다. 서울 동부 지역 암반 지하수의 수질 특성을 보면, 강북, 노원, 도봉 등 중랑천 상류 지역의 지하수가 동대문, 성동, 송파구 등 하류쪽의 지하수에 비해 낮은 TDS 함량을 갖는 경향이 있다. 서부 지역 지하수는 동부 지역에 비해 높은 TDS 값을 보이며, 공단부지 면적이 큰 영등포, 금천, 구로구 일대 및 종로, 중구 등 교통혼잡지역 등에서 매우 높은 TDS 함량을 나타내었다. 결국, 서울시 지하수의 TDS 함량은 수-암 반응보다는 인위적인 오염원에 의해 크게 지배되는 것으로 판단된다.

• Fire Science and Engineering
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• v.33 no.3
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• pp.51-55
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• 2019

To prevent ozone depletion caused by CFCs, the replacement of Halon with clean agents has been developed in the fire protection field along with refrigerants, detergents, and foaming agents. The alternatives for Halon 1211 have been developed in the portable fire extinguisher area and HCFC-123 is used widely as a clean fire extinguishing agent. The type of expellant gas is important because their own vapor pressure is low. In this study, HCFC-123, HCFC-124, HFC-125, and Novec-1230 were selected as fire extinguishing agents and CO₂, which is expected to improve the fire extinguishing ability, was chosen as the expellant gas. For each agent, experiments changing the agent and CO₂ amount were carried out and HCFC-123 showed a good result, as expected. The extinguisher, HCFC-123 of 1.5 kg, showed the same ability to suppress a class A and B fire as the extinguisher, HCFC-123 of 2.5 kg, which is currently sold on the market. According to this result, the expellant gas has a subsidiary fire extinguish effect. This can reduce the amount of HCFC fire extinguishing agent, which is categorized in the phase-out alternatives, and is a more eco-friendly and economical fire extinguisher than the previous one. This study can also help solve the problems of CO₂ fire extinguishers for class B and C fires, and can be used to extinguish electric and electron facilities fire, which contains large amounts of class A fire combustibles.

• 월간 기계설비
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• s.163
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• pp.85-109
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• 2004

가스난방기인 GHP의 인기가 급부상하면서 1995년 선을 보인 후 GHP시장이 올 한해 보급대수만 3천5백대에 달할 것이라는 소식이며 이는 지난해보다도 3배이상 늘어난 수치이다. GHP가 각광을 받는 것은 청정연료인 가스를 사용하고 우수한 냉$\cdot$난방효과를 얻을 수 있는 데다 기기 수명이 길고 유지보수가 간단하게 이루어지는 등 장점이 많다는 점에서다. 또한 친환경적이라는 측면에서 매우 긍정적이며 여름철 전력난 해소에도 기여한다는 점에서 국가경제에도 매우 크다고 할 수 있다.