• 한국대기환경학회지
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• 제33권4호
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• pp.393-402
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• 2017

In this study, greenhouse gas (GHG) reductions from bioenergy (biogas, biomass) have been estimated in Korea, 2015. This study for construction of reduction inventories as direct and indirect reduction sources was derived from IPCC 2006 guidelines for national greenhouse gas inventories, guidelines for local government greenhouse inventories published in 2016, also purchased electricity and steam indirect emission factors obtained from KPX, GIR respectively. As a result, the annual GHG reductions were estimated as $1,860,000tonCO_{2eq}$ accounting for 76.8% of direct reduction (scope 1) and 23.2% of indirect reduction (scope 2). Estimation of individual greenhouse gases (GHGs) from biogas appeared that $CO_2$, $CH_4$, $N_2O$ were $90,000tonCO_2$ (5.5%), $55,000tonCH_4$ (94.5%), $0.3tonN_2O$ (0.004%), respectively. In addition, biomass was $250,000tonCO_2$ (107%), $-300tonCH_4$ (-3.2%), $-33tonN_2O$ (-3.9%). For understanding the values of estimation method levels, field data (this study) appeared to be approximately 85.47% compared to installed capacity. In details, biogas and biomass resulting from field data showed to be 76%, 74% compared to installed capacity, respectively. In the comparison of this study and CDM project with GHG reduction unit per year installed capacity, this study showed as 42% level versus CDM project. Scenario analysis of GHG reductions potential from bioenergy was analyzed that generation efficiency, availability and cumulative distribution were significantly effective on reducing GHG.

• Carbon letters
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• 제25권
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• pp.89-94
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• 2018

In this study, we tried to prepare an isotropic spinnable pitch which can be useful to prepare the general purpose carbon fiber through the co-carbonization of biomass tar with ethylene bottom oil under two different preparation methods (atmospheric distillation, pressurized distillation). The results showed that the ethylene bottom oil added co-carbonization was very effective to decrease of the oxygen contents for obtaining a stable spinnable pitch. The pressurized distillation was more effective to reduce the oxygen functional groups of pitches than atmospheric distillation. The obtained spinnable pitch by the pressurized distillation showed higher pitch yield of 42% and lower oxygen content of 9.12% than the spinnable pitch by the atmospheric distillation. The carbon fiber derived from the pressurized distillation spinnable pitch by carbonization at $800^{\circ}C$ for 5 min showed that the higher tensile strength of carbon fiber was increased up to 800 MPa.

• Journal of Korean Society for Atmospheric Environment
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• 제24권E1호
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• pp.32-43
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• 2008

Source samples were collected to construct source profiles for 9 different source types, including soil, road dust, gasoline/diesel-powered vehicles, a municipal incinerator, industrial sources, agricultural/biomass burning, marine aerosol, and a coal-fired power plant. Seasonal profiles for 'Chinese aerosol', aerosols derived from the urban area of China, were reconstructed from seasonal $PM_{2.5}$ compositions reported in Beijing, China. Ambient $PM_{2.5}$ at a receptor site was also measured during each of the four seasons, from April 2001 to February 2002, in Seoul. The Chemical Mass Balance receptor model was applied to quantify source contributions during the study period using the estimated source profiles. Consequently, motor vehicle exhaust (33.0%), in particular 23.9% for diesel-powered vehicles, was the largest contributor affecting the $PM_{2.5}$ levels in Seoul, followed by agricultural/biomass burning (21.5%) and 'Chinese aerosol' (13.1%), indicating contributions from long-range transport. The largest contributors by season were: for spring, 'Chinese aerosol' (31.7%); for summer, motor vehicle exhaust (66.9%); and for fall and winter, agricultural/biomass burning (31.1% and 40.1%, respectively). These results show different seasonal patterns and sources affecting the $PM_{2.5}$ level in Seoul, than those previously reported for other cities in the world.

• Journal of Microbiology and Biotechnology
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• 제23권7호
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• pp.897-904
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• 2013

Seven bacterial isolates (viz., AB05, AB10, AB11, AB12, AB14, AB15, and AB17) were derived from the rhizosphere and evaluated in terms of plant growth-promoting activities and the inhibition of Phytophthora infestans affecting tomatoes in Korea. According to 16S rDNA sequencing, a majority of the isolates are members of Bacillus, and a single isolate belongs to Paenibacillus. All seven isolates inhibited P. infestans by more than 60% in vitro. However, AB15 was the most effective, inhibiting mycelial growth of the pathogen by more than 80% in vitro and suppressing disease by 74% compared with control plants under greenhouse conditions. In a PGPR assay, all of the bacterial isolates were capable of enhancing different growth parameters (shoot/root length, fresh biomass, dry matter, and chlorophyll content) in comparison with non-inoculated control plants. AB17-treated plants in particular showed the highest enhancement in fresh biomass with 18% and 26% increments in the root and shoot biomass, respectively. However, isolate AB10 showed the highest shoot and root growth with 18% and 26% increments, respectively. Moreover, the total chlorophyll content was 14%~19% higher in treated plants.

• 농업과학연구
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• 제47권2호
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• pp.305-313
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• 2020

Root hair development has the potential to increase crop yields and at the same time to decrease fertilizer use, which will be required in the next 30 years to meet the demand for crop-derived commodities in a world with decreasing available natural resources. Root hair defective six (RHD6) encoding a basic helix-loop-helix transcription factor, is associated with root hair differentiation, and its roles are root hair initiation and elongation. Grass plants, rice and Brachypodium have been used as model plants to study the gene function of the root hair defective six like (RSL) subfamily which is orthologous to AtRHD6. The RSL subfamily has an identical gene function with AtRHD6 which is involved with root hair differentiation as well. Plants with longer root hairs within a species should have an improved Pi uptake efficiency; therefore, we would expect that a plant with a high Pi uptake could contribute to increasing the plant yield. We achieved increased root hair length by manipulating the RSL subfamily genes. It is expected that in these transgenic plants, the long root hairs would be sufficient to improve the Pi uptake and hence improve biomass and yield component (tiller, spikelet number, and spikelet weight) of the plant. Here, we demonstrate that Brachypodium transgenic plants overexpressing the BdRSL subfamily genes have an improved biomass and grain yield. The result of this study could be applied to important crop plants like rice.

• Elastomers and Composites
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• 제56권3호
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• pp.136-151
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• 2021

Biomass lignin, a waste produced during the paper and bio-ethanol production process, is a cheap material that is available in large quantities. Thus, the interest in the valorization of biomass lignin has been increasing in industrial and academic areas. Over the years, lignin has been predominantly burnt as fuel to run pulping plants. However, less than 2% of the available lignin has been utilized for producing specialty chemicals, such as dispersants, adhesives, surfactants, and other value-added products. The development of value-added lignin-derived co-products should help make second generation biorefineries and the paper industry more profitable by valorizing lignin. Another possible approach towards value-added applications is using lignin as a component in plastics. However, blending lignin with polymers is not simple because the polarity of lignin molecules results in strong self-interactions. Therefore, achieving in-depth insights on lignin characteristics and structure will help in accelerating the development of lignin-based products. Considering the multipurpose characteristics of lignin for producing value-added products, this review will shed light on the potential applications of lignin and lignin-based derivatives on polymeric composite production. Moreover, the challenges in lignin valorization will be addressed.

• 신재생에너지
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• 제19권4호
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• pp.11-19
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• 2023

Levulinic acid (LA) derived from cellulosic biomass, serves a crucial intermediate that can be used in various chemical conversions. This study focused on optimizing the production of LA using two types of pretreated rice husk (de-ashed and delignificated cellulosic biomass) in a batch reaction system through catalytic conversion with sulfuric acid. To determine the optimal conditions, the conversions of glucose and α-cellulose were examined to compare the effects of pretreatment on the rice husk. The experimental parameters covered a broad spectrum, including temperatures ranging from 140℃ to 200℃, a reaction time was up to 600 minutes, and a substrate to catalyst (acid solution) ratio of 100 g/L. The highest LA yield was 44.8%, achieved from de-ashed rice husk with 3.0 wt.% of sulfuric acid at 180℃ and with a reaction time of 180 minutes. In the case of the delignificated rice husk, a LA yield of 43.6% was obtained with 3.0 wt.% of sulfuric acid at 200℃ and with reaction time of 30 minutes.

• 대한원격탐사학회지
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• 제30권4호
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• pp.417-430
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• 2014

본 연구는 현재 NASA에서 제공되는 operational OMI HCHO 관측 값에서 에러를 발견하여, 월평균 HCHO 자료의 시계열에 4 차 다항식을 피팅함으로써 구한 배경 모수화(parameterization)값을 이용하여 OMI HCHO 자료의 보정을 수행하였다. 보정후의 OMI HCHO는 동태평양과 서태평양 지역에서 -1.48%, 0.65%/year 경향성을 보였으며 이 수치는 GOME(-0.99%, 1.1%/year)과 SCAIMACHY(-0.92%, 0.03%/year)의 경향성과 유사한 결과이며 적절하게 비정상적인 배경 HCHO 농도의 증가가 제거되었음을 나타낸다. 이 자료의 검증과 분석은 EOF와 SVD 통계적 분석 방법을 사용하여 아프리카 지역에서 다양한 위성 관측 값과의 (HCHO, CO, $NO_2$ 그리고 firecount) 시공간 변동성의 일치성을 비교 분석함으로써 수행되었다. 아프리카에서 MOPITT CO, OMI $NO_2$, SCIAMAHCY 그리고 OMI HCHO의 EOF와 SVD 분석 결과는 생태계화재(biomass burning)의 시공간 변동성 분포와 매우 높은 일치성을 보여준다. 그러나 OMI HCHO 관측 값은 화재가 가장 강하게 발생하는 지역의 풍하측에서 최대 값이 보이며, 화재 발생이 가장 높은 1월에 다소 낮은 HCHO 값이 보이는 등 시공간적으로 생태계 화제 분포와 차이를 보인다. 이것의 원인으로 우리는 이 지역의 열대우림의 식물활동(biogenic activity)영향으로는 설명할 수 없고, biomass burning 에어로졸에 의한 잘못된 AMF 계산이 OMI HCHO 산출에 사용됨으로써 발생한 오차라는 것을 밝혔다. AMF와 관련된 오차가 적절하게 보정된다면, 아프리카 지역의 HCHO 시공간 변동성은 생태계 화제의 변동성을 따를 것이라 예상된다. 따라서 본 연구는 통계적 기법이 위성 자료를 평가하는데 매우 효율적인 방법임을 제안한다.

• Ecology and Resilient Infrastructure
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• 제4권3호
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• pp.149-155
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• 2017

버드나무 속 식물은 하천 복원시 사용되는 대표적인 생물재료이고 하천에서 주요 관리대상이 되는 식물이다. 낙동강의 모래하천 하안에서 선버들과 왕버들의 수령에 따른 생장 변화를 파악하기 위하여, 이들의 생물량 추정을 위한 상대생장식을 유도하고 입지 연령에 다른 이들 군집에서 밀도, 줄기 높이, 기저면적 및 생물량을 조사하였다. 선버들은 발아한 후 3년과 왕버들은 6년까지 줄기 밀도가 급격하게 감소하여 자기 솎음이 강하게 일어났다. 두 식물의 줄기 높이는 선버들은 수령 15년에 7.5 m까지 왕버들은 수령 13년에 14 m까지 증가하였다. 또한 지상부 생물량은 생장초기에 급속히 증가하였으며 선버들은 수령 13년에 17 ton DM/ha까지 왕버들은 수령 13년에 1,110 ton DM/ha까지 증가하였다. 한편 본 연구에서 유도된 버드나무 속 식물의 상대생장식을 이용하면 이들 식물의 생물량을 객관적으로 추정할 수 있어서 하천에서 수목 관리하는데 도움이 될 것으로 기대된다.

• 한국환경과학회지
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• 제14권2호
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• pp.251-258
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• 2005

Statistical analysis between operating parameters and effluent quality on advanced wastewater treatment plant was performed. Through factor analysis four factors derived varimax rotation were selected each plant. Four components explained $80\%,\;82\%$ of the total variance of the process, respectively. The components on MLE plant were identified in the following order: 1) HRT increase and BOD load decrease by influent decrease, 2) Biomass, 3) SVI increase by internal return increase, 4) Microbial diversity by SRT increase. On $A_2O$ plant, we defined them as follows: factor 1, high MLSS by return rate increase, HRT increase by influent decrease; factor 2, biomass; factor 3, BOD of influent; factor 4 was relate to DO.