• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.94-99
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• 2014

Recently, trends in new transportation system development have been primarily focused on sustainable and ecofriendly mobility solutions. The personal rapid transit (PRT) system has been considered a promising candidate in this category; its competitiveness is being improved through convergence with cutting-edge electric vehicle (EV) technologies. However, battery-powered vehicles pose difficult technical challenges in attempts to achieve reliable and efficient operation. In this study, a design approach for a solar-power assisted PRT system is presented with small-scale demonstrations aimed at circumventing challenges facing its adoption, as well as helping speed the transition to electric-powered ground transportation. From the results, it is expected that flexible photovoltaic (PV) cells will be able to supply 11% of the power required by the service equipment installed in a prototype vehicle. In particular, flexible photovoltaic (PV) cells are advantageous in terms of cost, weight, and design considerations. Most importantly, the cells' flexibility and attach-ability are expected to give them great potential for extended application in various areas.

• Clean Technology
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• v.26 no.2
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• pp.131-136
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• 2020

Biomass bamboo charcoal is utilized as anode for lithium-ion battery in an effort to find an alternative to conventional resources such as cokes and petroleum pitches. The amorphous phase of the bamboo charcoal is partially converted to graphite through a low temperature graphitization process with iron oxide nanoparticle catalyst impregnated into the bamboo charcoal. An optimum catalysis amount for the graphitization is determined based on the characterization results of TEM, Raman spectroscopy, and XRD. It is found that the graphitization occurs surrounding the surface of the catalysis, and large pores are formed after the removal of the catalysis. The formation of the large pores increases the pore volume and, as a result, reduces the surface area of the graphitized bamboo charcoal. The partial graphitization of the pristine bamboo charcoal improves the discharge capacity and coulombic efficiency compared to the pristine counterpart. However, the discharge capacity of the graphitized charcoal at elevated current density is decreased due to the reduced surface area. These results indicate that the size of the catalysis formed in in-situ graphitization is a critical parameter to determine the battery performance and thus should be tuned as small as one of the pristine charcoal to retain the surface area and eventually improve the discharge capacity at high current density.

• Clean Technology
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• v.24 no.1
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• pp.1-8
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• 2018

As the social demands for environmental pollution increase and regulations on the dyeing process wastewater are strengthened, supercritical dyeing process has been attracting attention as an alternative technology to reduce wastewater and energy consumption. In the supercritical dyeing process where carbon dioxide is used as a solvent instead of water as a solvent, there is no wastewater generated. The unfixed dyes can be reused later which makes the process environment-friendly. Also, after dyeing process, dried textiles can be obtained without additional drying process, which makes the process energy efficient. In this article, we have summarized the development of the supercritical dyeing process along with the research in Korea today and compared the principle of supercritical dyeing process with conventional dyeing process. To further explain the principle, studies of the distribution factor and mass transfer of dyes in supercritical carbon dioxide and fibers, as well as solubility between supercritical $CO_2$ and dyes are discussed. The dynamic behavior of dyes in supercritical dyeing apparatus and summary of the supercritical dyeing facilities developed around the world are also discussed. Finally, we suggest the direction of research and development for optimization of supercritical dyeing process and application to synthetic fibers and natural fibers except for polyester.

• Journal of Korean Society of Archives and Records Management
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• v.16 no.2
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• pp.173-183
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• 2016

Fungi are a major cause of cultural and biological degradation in museum storages and archives libraries. In addition, fungi produce toxins and can cause skin allergies. In particular, fungi coming into contact with the skin through the hands of administrators dealing with cultural properties, archives, and books can lead to secondary infections. To prevent this, applying hand sanitizer, which is readily available in the market, is recommended. However, such hand sanitizer can effectively disinfect against bacteria but not fungi. As such, researching for an alternative is required. In this study, we developed a hand sanitizer composed of active ingredients - geranial, cineol, menthol, and Chamaecyparis obtusa - and performed a disinfection test, which targets 10 kinds of species (Alternaria citrimacularis, Alternaria consortialis, Aspergillus niger, Aspergillus versicolor, Cladosporium sphaerospermum, Coniothyrium aleurites, Penicillium brevicompactum, Penicillium corylophilum, Penicillium paneum, and Penicillium polonicum), of fungi investigated in museums and libraries. It was then confirmed to exhibit excellent disinfecting effects. Thus, this hand sanitizer is expected to prevent skin diseases and secondary infections in administrators dealing with cultural properties, archives, and books.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.47-47
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• 2011

국내의 기능성 난연성 섬유 제조기술은 원사 자체에 난연제가 포함된 상태인 난연 PET 원사나, 일반 PET 원단에 후방염 처리한 원단이 사용되기에 난연 방염성능이 만족스럽지 못하고 친환경적이지 못한 실정이다. 오늘날 세계 난연섬유 시장 규모는 10조원에 이르고 있으며 국내에서도 화재에 대한 경각심이 높아지는 추세이므로 기능성을 갖춘 고부가가치 난연소재의 개발이 시급하다. 폴리페닐렌술피드(PPS)는 내열성 및 내화학약품성이 뛰어난 열가소성 고분자로 용융방사가 가능하다. 난연성이 높은 양모섬유 또는 아크릴계 난연섬유, 아라미드 섬유 등은 비용 문제로 범용화에 한계가 있으므로 비교적 저렴한 PPS 섬유가 개발될 경우 범용화를 기대할 수 있다. 현재는 PPS 섬유가 특수한 용도에 주로 사용되고 있으나 우수한 난연 특성을 이용하여 일반 용도로의 사용 및 수요가 급격히 늘어날 것으로 예상되며 우선적으로 인테리어용 원단, 특히 커튼이나 소파용 원단으로 용도 전개가 가능할 것으로 판단하였다. 본 연구에서는 소파용 PPS 원단의 후가공 조건의 선정 및 불소계 발수방오가공을 위한 최적의 조건을 선정하고자 하였다. Padding(wet pick up율 $80{\pm}3%$)-Drying($105^{\circ}C$, 2.5min)-Curing은 시간은 1분으로 고정시킨 후, 온도를 150, 160, 170, 180, 190, $200^{\circ}C$에서 처리하여 Yellowness값을 측정한 결과, 온도가 높아질수록 Yellowness값이 커지는 것으로 미루어 보아 PPS원단은 높은 열에 영향을 받아 황변 현상이 일어나는 것으로 사료된다. 특히 $180^{\circ}C$를 기점으로 값에 큰 변화를 보였으므로 최적의 열처리 온도는 $170^{\circ}C$로 선정하여 이후의 실험을 진행하였다. 또한 큐어링 시간이 황변에 미치는 영향을 분석한 결과 온도에 의한 영향에 비해 적은 편으로 사료되었으나, 1.5min을 기점으로 Yellowess값이 높아졌으므로 최적의 열처리 시간을 1분으로 선정하였다. 최종 가공조건인 $170^{\circ}C$, 1분에서 처리한 시험포는 처리전 원단과 비교하였을 때, ${\Delta}$Yellowness가 2.84 정도로 나타났다. 그 후, PPS 원단에 불소가공제 (TG-991N, 동인텍스켐)의 적정 농도를 선정하기 위해 1~7%까지 농도를 높이며 처리한 결과, 불소가공제의 농도가 높아짐에 따라 황변현상이 나타남을 알 수 있었다. 농도가 높아짐에 따라 Yellowness값은 증가하다가 4% 이후 완만해지는 것을 알 수 있었으므로 IPA/Water Drop test와 발수도시험 (KS K 0590;2008)을 통해 적정 농도를 선정하였다. PPS 원단은 불소가공제의 농도가 높아짐에 따라 발수도가 우수해졌으며, 가공제 농도 3% 처리만으로도 우수한 발수도를 나타내었으나 100% 발수를 위해서는 가공제 농도가 5% 이상 처리되어야 하는 것을 확인할 수 있었다.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.312-331
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• 2019

An offshore waste disposal facility refers to a landfill site for final landfilling of stabilized inorganic solid waste such as land and marine waste incineration materials, and the aim of such a facility is to solve the problem of insufficient waste disposal space on land and create and develop environmentally friendly marine spaces. The purpose of this study is to prepare guidelines for the construction of offshore waste disposal facilities, which reflect the need and importance of paying sufficient heed to environmental considerations from the initial stage of the project, in order to investigate, predict, and assess how such guidelines will affect the marine environment in relation to the construction of offshore waste disposal facilities, with the goal of minimizing the impact on and damage to the environment. For the purpose of this research, guidelines focusing on the construction of offshore waste disposal facilities were derived through an analysis of domestic cases and similar foreign cases and an assessment of their level of compliance with existing EIA guidelines through the operation of a discussion forum. In order to review the EIA report on similar cases in Korea, 17 EIA documents (2005~2016) for dredged soil dumping areas and ash ponds of thermal power plants were analyzed to investigate the status of marine organisms, marine physics, marine water quality, and marine sediment and to understand what types of problems can occur and what improvement measures can be taken. The purpose of these guidelines were to minimize damage to the marine environment by promoting EIA protocols in accordance with scientific and systematic procedures, to reduce the consultation period related to projects, to resolve social conflicts, and to reduce economic costs.

• Journal of Life Science
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• v.28 no.12
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• pp.1501-1506
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• 2018

Edible insects have recently been increasingly promoted as a source of protein. As the number of farms rearing these insect increases, it is important to develop safe and nutritious feed sources to improve their commercial quality. The aim of the current study was to determine the effect of food by-products as feed supplements for the Korean rhinoceros beetle, Allomyrina dichotoma, which has been registered as a general food ingredient in Korea. We compared the effects of waste citrus peel, soybean curd cake, soybean oil meal, and brewers' dried grain on the growth of third instar larvae of A. dichotoma. Groups of larvae were fed with fermented sawdust and nine different combinations of the above by-products and the effects on their growth were measured until pupation. The highest survival rate was with feed supplemented with 10% brewers' dried grain (66.7%, p<0.05), and these larvae were also 26% heavier (p<0.05) than the control group that received no supplementation. In the 10% brewers' dried grain group, the larval period of third instar was shortened by almost 28 days (p<0.01) compared to the control group. Of all the groups, only that which was fed the brewers' dried grain supplement showed more than a 90% pupation rate (p<0.05). Therefore, brewers' dried grain may be useful as a source of feed for A. dichotoma.

• Journal of Korea Water Resources Association
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• v.55 no.7
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• pp.531-543
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• 2022

Integrated water resources management (IWRM) has focused on efficient response to various water related disasters by climate change. In particular, more flexible usage of conventional water resources infrastructures is expected to provide an eco-friendly water management. Multi-purpose dams and water supply dams are well known as water management facilities for securing and supplying water in drought season. Recently, based on the report '2021 multi-purpose use of hydropower dams in Han river', contribution of hydropower dams on water resources management is becoming more significant beyond the traditional role of hydropower generation. In drought conditions, the dams control water supply depending on the pre-defined drought stages. In the case of multi-purpose dams, an operation standard during drought has been already prepared and applied; however, for the hydropower dams, specific standards are not fully prepared yet in South Korea. In this study, a method for calculation of standard water storage and discharge reduction of hydropower dams according to drought stage is newly proposed reflecting the characteristics of hydropower dams. The proposed method was applied to the hydropower dams in Han river, where six hydropower dams are located. A case study of the historical droughts occurred in 2014-2017 demonstrated that the proposed hydropower dam operation rule could improve the water supply stability under severe drought conditions compared to the conventional operations. In the future, the role of hydropower dams for water resources management is expected to become more important, and this study can be widely used for water supply planning such as drought response using hydropower dams.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.969-977
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• 2022

In order to respond to the increase in water disasters due to climate change and urbanization, research on low impact development (LID) techniques and application to cities are expanding. The LID technique is a technology that reduces rainwater runoff in the city, controls various water disasters such as flash floods, etc. in an eco-friendly way, and restores the urban water circulation system to a natural water circulation system. However, quantitative analysis of stormwater runoff reduction through the LID technique is insufficient. Therefore, this study analyzed the ratio of the permeable area required to reduce the surface runoff of rainfall (25 mm/hr, 50 mm/hr, 100 mm/hr) with respect to the impervious watershed area of the old city using the permeable pavement. As a result of the analysis, it was found that a permeable area ratio of 7.14 to 12.63% of the total area was required for 25 mm/hr, 15.79 to 26.97% for 50 mm/hr, and 30 to 55.81% for 100 mm/hr.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.350-356
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• 2011

Environment-friendly agro-materials tend to be preferred to chemical insecticides recently. For this reason, many studies were conducted to develop environment-friendly insecticides containing natural materials. The purpose of this study was to assess ecotoxicity for 5 plant essential oils (Thyme white, Clove bud, Cassia, Lavender, Lemon eucalyptus) expected to prevent from pests and be used for agro-materials. Target species used to assess acute toxicity were aquatic invertebrate (Daphina magna), fish (Oryzias latipes), honeybee (Apis mellifera L.) and earthworm (Eisenia fetida). The EC50 value, toxicological responses of thyme white, clove bud, and cassia to Daphina magna were 2.5, 2.8, and $6.9mg\;L^{-1}$ respectively and these values were moderately toxic according to standard of USEPA. $EC_{50}$ of Lavender and lemon eucalyptus were >$10mg\;L^{-1}$ then they were considered as slightly toxicity. In case of acute toxicity test to fish, $LC_{50}$ of thyme white and cassia were 6.7 and $7.5mg\;L^{-1}$ each other. The other plant essential oils indicated $LC_{50}$ >$10mg\;L^{-1}$. Acute contact and oral toxicity test to Honeybee were conducted. As a result, $LD_{50}$ of all essential oils were >$100{\mu}g$ a.i. $bee^{-1}$ in both of tests. In case of acute toxicity test to earthworm, $LC_{50}$ of thyme white, clove bud, cassia, lavender, and lemon eucalyptus were 149, 230, 743, 234, and $635mg\;kg^{-1}$, respectively. In conclusion, if the safety for earthworm is confirmed, 5 plant essential oils are expected to be use for environment-friendly insecticide materials with low risk against ecosystem and contribute to developing environment-friendly agro-materials.