• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.36-36
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• 2012

Drainage water in lowland paddy fields is quantitatively influenced recycle and/or repeated irrigation by irrigation facilities, i.e. pumps, check gates, small reservoirs and so on. In those drainage channels, nutrients accumulation and increasing organic matters are considered to be occurred, and water quality would be degraded not only environmental aspect but irrigation purpose. In general, Total Nitrogen (T-N) is interested water quality index in irrigation water, because high nitrogen concentration sometimes caused decreasing rice production by excess growth and fallen or degrading quality of taste, then, farmers would like to clear water less than 1mg/L of T-N concentration. In drainage channel, it is known that the nitrogen concentration change is influenced by physical, chemical and biological properties, i.e, stream or river bed condition, water temperature, other water quality index, and plant cover condition. In this study, discharge data (velocity and level) in a drainage channel was monitored by an Acoustic Doppler system and water quality was sampled at same time in 2011. So those data was analyzed by multi regression model to realize hydrological and environmental factors to influence with nitrogen concentration. The results showed the difference tendency between irrigation and non-irrigation period, and those influenced factors would be considered in water quality model developing in future.

• 한국응용과학기술학회지
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• 제25권2호
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• pp.130-136
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• 2008

$xTiO_2$-$ySiO_2$ system photocatalysts were developed by sol-gel method based on the change of production parameters, and their structure of crystallization and the specific surface area were measured. Considering the efficiency of the ethanol and phenol degradation using the catalyst, the conclusions were obtained as follows: By means of X-ray analysis of $xTiO_2$-$ySiO_2$ powder that is obtained from Titanium and Silicon alkoxide by sol-gel process, it is shown that crystal structure of anatase type is a dominating structure and, on the other hand, the structure of rutile also partly exists. The increase of $SiO_2$ contents causes the decrease of the degree of crystallization of the gel, whereas the specific surface area preferentially increases. It is shown that more than 90% of ethanol and phenol are degraded when reaction time is about three and an hours, and the maximum degradation rate of ethanol and phenol is shown in $60TiO_2$-$40SiO_2$ catalyst.

• Current Optics and Photonics
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• 제1권1호
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• pp.7-11
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• 2017

In this study, multilayered graphene was easily transferred to the target substrate in one step using thermal release tape. The transmittance of the transferred graphene according to the number of layers was measured using a spectrophotometer. The sheet resistance was measured using a four-point probe system. Graphene formed using this transfer method showed almost the same electrical and optical properties as that formed using the conventional poly (methyl methacrylate) transfer method. This method is suitable for the mass production of graphene because of the short process time and easy large-area transfer. In addition, multilayered graphene can be transferred on various substrates without wetting problem using the one-step dry transfer method. In this work, this easy transfer method was used for dielectric substrates such as glass, paper and polyethylene terephthalate, and a sheet resistance of ~240 ohm/sq was obtained with three-layer graphene. By fabricating organic solar cells, we verified the feasibility of using this method for optoelectronic devices.

• Journal of Animal Science and Technology
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• 제61권3호
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• pp.122-137
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• 2019

Methane, one of the important greenhouse gas, has a higher global warming potential than that of carbon dioxide. Agriculture, especially livestock, is considered as the biggest sector in producing anthropogenic methane. Among livestock, ruminants are the highest emitters of enteric methane. Methanogenesis, a continuous process in the rumen, carried out by archaea either with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to methane or with methylotrophic pathway, which the substrate for methanogenesis is methyl groups. For accurate estimation of methane from ruminants, three methods have been successfully used in various experiments under different environmental conditions such as respiration chamber, sulfur hexafluoride tracer technique, and the automated head-chamber or GreenFeed system. Methane production and emission from ruminants are increasing day by day with an increase of ruminants which help to meet up the nutrient demands of the increasing human population throughout the world. Several mitigation strategies have been taken separately for methane abatement from ruminant productions such as animal intervention, diet selection, dietary feed additives, probiotics, defaunation, supplementation of fats, oils, organic acids, plant secondary metabolites, etc. However, sustainable mitigation strategies are not established yet. A cumulative approach of accurate enteric methane measurement and existing mitigation strategies with more focusing on the biological reduction of methane emission by direct-fed microbials could be the sustainable methane mitigation approaches.

• 분석과학
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• 제8권1호
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• pp.91-99
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• 1995

축산폐기물의 처리에 이용되는 혐기성 및 호기성 소화법은 복잡한 처리기술과 유지관리 및 과다한 처리비용 등의 문제점이 있으며, 재활용법인 퇴비화는 긴 부숙기간, 수분조절제 사용 및 완숙도 판정의 어려움 등의 문제점이 있다. 이와 같은 축산폐기물의 기존 처리법의 문제점을 탈피하고 축산폐기물을 이화학적 및 위생학적으로 안정화시켜 축산폐기물 자체의 환경 부적인 측면인 악취, 기생충 및 병원균, 혐오감 등을 해소하며 처리물을 토양개량제 또는 유기질비료로 이용할 수 있는 축산폐기물의 안정화 처리 및 자원 재활용공정을 연구하였다. 본 논문은 대표적 축산폐기물의 하나인 돈분을 대상으로 안정화 반응조건을 확립하고 처리물의 안정성, 안전성, 위생성 및 비효성 등을 평가하는 목적으로 수행하였다. 연구결과 최적 안정화를 위한 첨가제의 투여량은 고형분 대비 약 30%, 반응시간은 약 5분이며, 건조는 자연건조 후 강제건조가 적합한 것으로 나타났다. 최종 안정화 처리물은 약알칼리성으로서 유기물 함량은 약 50% 내외, 비료성분인 총 질소, 인산 및 칼리의 합은 약 5.3%였다. 또한 안정화 처리시 암모니아, 황화수소 등의 악취물질이 거의 제거되었고, 일반세균과 대장균은 98% 이상, 기생충은 완전 사멸되었다. 따라서 돈분의 안정화 처리물은 토양개량제 또는 유기질비료로 사용될 수 있을 것으로 판단된다.

• 한국미생물·생명공학회지
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• 제37권4호
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• pp.365-370
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• 2009

재구성 지방질의 기질로서 사용될 수 있는 중쇄지방산을 함유한 디글리세리드(DG)를 생산하기 위하여 리파제를 사용하여 중쇄지방산과 모노글리세리드(MG)로부터 DG를 생산하는 유기용매를 사용하지 않는 반응 시스템을 고안하였다. 조사된 리파제 중에 Lipozyme RM IM과 Novozym 435만이 중쇄지방산(carpylic acid, caproic acid, capric acid)과 MG로부터 DG를 효과적으로 생산하였다. 고정화 효소인 Lipozyme RM IM을 사용하여 중쇄지방산인 카프릴산과 MG를 반응시킴으로써 DG 생산을 위하여 molecular sieve 첨가에 의한 반응혼합액 중의 수분 제거, 고정화 효소의 수분함량, 반응온도, MG/카프릴산의 몰비율 등의 생산 조건을 최적화하였다. Molecular sieve를 첨가 하였을 때 약 8%의 DG 함량이 증가되었으며 고정화효소(초기 수분함량: 3.8%(w/w))의 수분을 2.8%(w/w) 이상 감소시킴으로써 44%의 DG를 생산할 수 있었다. 최적의 반응 온도는 $60^{\circ}C$로 확인되었으며 $60^{\circ}C$에서 $25^{\circ}C$로의 온도 변화는 FFA의 함량이 증가하여 DG 생산에 적합하지 아니하였다. 조사된 모든 몰비율에서 반응 24시간 후의 DG의 생산량은 40% 전후로 큰 차이를 나타내지 않았으나 화학양론적인 몰비율 1:1(MG/caprylic acid)에서 가장 많은 DG가 생산되었다. 또한 MG와 카프릴산의 몰비율이 0.3에서 1.8로 높아질수록 반응물 중의 FFA의 함량이 34%에서 13%로 감소하였고 MG 함량은 37%에서 50%로 증가하였다.

• 농촌지도와개발
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• 제16권2호
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• pp.363-384
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• 2009

This study aimed at finding directions for Korean agriculture to establish a new paradigm of sustainable development. Various problematic issues and concerns in the environment necessitate the transformation of Korea's development paradigm from unconditional growth to "Green Growth" through new policies on green value and review of various advanced researches. In this research, the environment-friendly agriculture's problems, particularly in agribusiness were analyzed. Drawing from Michael Porter's Value Chain Analysis, this research developed a value chain model in agriculture that reflects the environment and the present situations. Future directions in the agriculture sector were also discussed. Korea realized food self-sufficiency through the green revolution in the early 1970s. However, a lot of problems have also occurred, including ground and water pollution and the destruction of ecosystems as a result of the overuse of pesticides and chemical fertilizers. In the late 1970s, the growing interest on environment-friendly agriculture led to the introduction of sustainable methods and techniques. Unfortunately however, these were not innovative enough to foster environment-friendly agriculture. Thereafter, the consumers' distrust on agricultural products has worsened and concerns about health have increased. In view of this, the Ministry of Food, Agriculture, Forestry and Fisheries introduced in December 1993 a system of Quality-Certified Products for organic and pesticide-free agri-foods. Although a fundamental step toward the sustainability of the global environment, this system was not enough to promote environment-friendly agriculture. In 2008, Korea's vision is for "Low Carbon Green Growth" to move forward while also coping with climate change. But primary sectors in a typical value chain do not consider the green value of their operations nor look at production from an environmental perspective. In order to attain sustainable development, there is a need to use less resources and energy than what is presently used in Korean agricultural and value production. The typical value chain should be transformed into a "closed-loop" such that the beginning and the end of the chain are linked together. Such structure allows the flow of materials, products and even wastes among participants in the chain in a sustained cycle. This may result in a zero-waste sustainable production without destroying the ecosystem.

• 유기물자원화
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• 제13권3호
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• pp.105-118
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• 2005

본 연구는 현행 음식물류폐기물 통계 체계 문제점 및 개선점 분석을 목적으로 수행되었으며, 4개 지역(고밀도, 중밀도, 중저밀도, 저밀도)을 대상으로 4계절에 걸친 표본조사를 실시하여 배출원별 원단위에 근거한 산출방식으로 해당 지역의 전체 발생량을 추론하였다. 이렇게 산출된 발생량과 현행 통계상에서 제시하고 있는 발생량 간의 차이를 분석하였으며, 이와 함께 112개 지자체를 대상으로 음식물류폐기물 산정 범위 및 방식 분석 등을 통해 국내 음식물류폐기물 통계 체계의 문제점 및 해결방안을 검토 하였다. 112개 지자체를 대상으로 한 설문 조사결과를 보면, 음식물 통계 산출 기준은 크게 5가지로 분류 된다. 대도시 및 중소도시의 경우, 자원화시설 반입량에 근거하는 지자체가 가장 많았으며, 도농지역 및 농어촌도시 일수록 원단위 발생량을 통한 추정에 의해 통계 산출이 이루어지는 것으로 나타났다. 4개 지역의 음식물류폐기물 발생량 표본조사 분석결과는 통계상에서 제시하는 결과와 10%~40% 높은 것으로 조사되었으며, 이는 기존 통계에서는 고려하지 않았던 미분리배출량의 포함이 가장 큰 이유로 판단된다. 또한, 분리배출량에 근거하여 발생량을 산출하는 지역이 원단위발생량을 이용하여 발생량을 단순 추정하는 지역에 비해 표본조사와 통계 자료 간 편차가 더 적은 것으로 조사되었다.

• 상하수도학회지
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• 제29권6호
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• pp.601-608
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• 2015

Pollutants removal efficiency in pretreatment(GAC filter, multi-media filter, disk filter) and RO facilities was investigated for the Jeju Samyang spring water source where raw water intake has been stopped due to sea water intrusion. In addition, preliminary feasibility analysis was conducted between RO and groundwater intake systems. Turbidity removal in 4 different pretreatment processes was less than 25% due to low concentration of turbidity(i.e., less than 0.21 NTU), while multi-media filter is recommended for the pretreatment facility based on the low organic content in raw water as well as cheaper operation and maintenance cost. The average concentration of $Cl^-$ in raw water was 691.4 mg/L, while that of RO permeate was 9.1 mg/L(i.e., removal efficiency was 98.4%). In addition, TDS removal efficiency was 98.1%, which was quite high. The production cost for RO system($Q=4,000m^3/d$) was $362.1won/m^3$ considering installation, operation and maintenance cost for 30 years. While that of groundwater was $262.6won/m^3$ which was low compared to the RO system. However, it is recommended to introduce RO system for Samyang water source rather than new groundwater development because Samyang water source has been discharged to the sea without any usage, while groundwater can be used for other purpose as a sustainable water source.

• 원예과학기술지
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• 제29권3호
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• pp.201-210
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• 2011

This experiment was conducted to investigate physical and chemical characteristics by volume fractions of root media using peatmoss, perlite, and vermiculite, along with effects on the growth of pot chrysanthemums (Dendranthema ${\times}$ grandiflorum 'Vemini') in a C-channel mat irrigation system. To evaluate the physico-chemical properties of 20 root media, the bulk density, particle density, total pore space, pore space, ash content, organic matter, pH, and electrical conductivity were measured and data were analyzed using principal component analysis (PCA). PCA scores revealed that physico-chemical properties changed by the blending of peatmoss, perlite, and vermiculite. The 20 root media were divided into three main groups by hierarchical cluster analysis. At the end of the experiment, the pH and EC of the root media were measured from media divided into four layers. The pH of root media without plants showed a strong linear relationship and the pH of root media with plants increased exponentially. The change of EC in the root medium was indicated as a hyperbolic curve. Plant growth characteristics according to growth in the 20 root media were analyzed by PCA. It was found that the mixing ratios of the root media affected plant growth characteristics. Therefore, mixing ratio is an important factor for pot-plant production in a subirrigation system.