• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.672-678
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• 2014

In this study, variations of fermentative hydrogen production and microbial community were investigated with different nitrogen concentration of food waste. Optimum hydrogen production rate was acquired at 200 mg/L nitrogen concentration of the food waste. Which was eqivalent to 83.43 mL/g dry biomass/hr. However, bio-hydrogen production was inhibitedly reduced at over 600 mg/L of nitrogen concentration whereas proportional relation between hydrogen production and B/A ratio were not observed. Most dominant specie of the microbial community analyzed was Clostridium sp. throughout PCR-DGGE analysis of 16S rDNA. It revealed that most contributing microorganism producing hydrogen were Enterococcus faecium partial, Klebsiella pneumoniae strain ND6, Enterobacter sp. NCCP-231, and Clostridium algidicarnis strain E107 in this experiment.

• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.197-203
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• 2018

Biochar is the carbon solid produced through the pyrolysis of a biomass from organic sources such as agricultural waste, animal manure, and sludge under limited or anaerobic conditions. Biochar has the effect of reducing greenhouse gases through the carbon sequestration method; additionally, biochar is known to function as a soil amendment. This experiment was conducted to evaluate the application of biochar on the growth characteristics of Chinese cabbage at Chungnam National University in Daejeon, Korea. The Chinese cabbage was grown for 50 days in a glasshouse in pots. A pruning branch was used to produce the bead and pellet forms of biochar through pyrolysis. The biochar was added to the soil at 0, 2, and 5% by weight. The Chinese cabbage with the 2% treatment of the bead form of biochar had the highest fresh weight ($149.43{\pm}15.92g\;plant^{-1}$) which was increased by 10% compared to the control ($136.91{\pm}31.46g\;plant^{-1}$). Moreover, for the 5% treatment of the bead form of biochar ($60.91{\pm}9.82g\;plant^{-1}$), the growth decreased by 57% compared to the control. As the content of the bead form of biochar increased, the shoot dry weight, leaf number, leaf length and lead width that appeared decreased. An increase in the total organic matter, Avail. $P_2O_5$, Ex. cation and EC was observed when the biochar content was increased. Our results support the application of 2% biochar in the bead form for increased growth of Chinese cabbage.

• Ocean and Polar Research
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• v.38 no.3
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• pp.225-234
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• 2016

This project sought to conduct an economic feasibility study regarding the commercial production of bio-hydrogen by the marine hyperthermophilic archaeon, Thermococcus onnurineus NA1 using carbon monoxide-containing industrial off-gas. We carried out the economic evaluation of the bio-hydrogen production process using the raw material of steel mill by-product gas. The process parameter was as follows: $H_2$ production rate was 5.6 L/L/h; the conversion of carbon monoxide was 60.7%. This project established an evaluation criterion for about 10,000 tonne/year. Inflation factors were considered as 3%. The operating costs were recalculated based on prices in 2014. The total investment required for development was covered 30% by capital and 70% by a loan. The operation cost for the 0.5-year test and integration, and the cost for the first three months in the 50% production period were considered as the working capital in the cost estimation. The costs required for the rental of office space, facilities, and other related costs from the construction through to full-scale production periods were considered as continuing expenses. Materials, energy, waste disposal and other charges were considered as the operating cost of the development system. Depreciation, tax, maintenance and repair, insurance, labor, interest rate charges, general and administrative costs, lubrication and miscellaneous expenses were also calculated. The hydrogen price was set at US$ 4.15/kg for the economic evaluation. As a result, the process was considered to be economical with the payback period of 6.3 years, NPV of 18 billion Won and IRR of 26.7%.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.66-70
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• 2017

Radioactive materials are used in medicine, non-destructive testing, and nuclear plants. Source localization is especially important during nuclear decommissioning and decontamination because the actual location of the radioactive source within nuclear waste is often unknown. The coded-aperture imaging technique started with space exploration and moved into X-ray and gamma ray imaging, which have imaging process characteristics similar to each other. In this study, we simulated $21{\times}21$ and $37{\times}37$ coded aperture collimators based on a modified uniformly redundant array (MURA) pattern to make a gamma imaging system that can localize a gamma-ray source. We designed a $21{\times}21$ coded aperture collimator that matches our gamma imaging detector and did feasibility experiments with the coded aperture imaging system. We evaluated the performance of each collimator, from 2 mm to 10 mm thicknesses (at 2 mm intervals) using root mean square error (RMSE) and sensitivity in a simulation. In experimental results, the full width half maximum (FWHM) of the point source was $5.09^{\circ}$ at the center and $4.82^{\circ}$ at the location of the source was $9^{\circ}$. We will continue to improve the decoding algorithm and optimize the collimator for high-energy gamma rays emitted from a nuclear power plant.

• Carbon letters
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• v.3 no.1
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• pp.1-5
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• 2002

The regional bio-wastes available in abundance in India were converted into porous carbon by heat treatment at different temperatures from $650-950^{\circ}C$. The wood retain shapes after pyrolysis though shrinkage occured both in axial and radial directions. The shrinkage in radial direction was found to be more than in axial direction in all woods. The density of woods and chars from these at a given temperature has been found to follow linear relationship. Chars were steam activated at temperature $700-800^{\circ}C$ for different times between 45-240 min. Both the temperature and time of activation with steam has a profound effect on surface area. Chars from softwoods like bagasse and castor oil plant were activated at lower temperature, i.e. $700-750^{\circ}C$ whereas hard wood chars have to be activated at higher temperature around $800^{\circ}C$. The morphology of wood as well as of chars has been studied by SEM. The comparison of the two showed that the nature of porosity in chars depends on precursor morphology, nature and physical state of wood and presence of inorganic compounds in the wood. Hard wood results in cross inter connected pores while softwood leads to fibriller structure. The present studies show that activated carbon with reasonably good surface area (${\sim}1000m^2/gm$) can be prepared from soft wood bio-wastes like bagasse and castor oil plant, while surface area ${\sim}1370m^2/gm$ was achieved from hard wood bio waste of pine wood.

• Journal of Plant Biotechnology
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• v.35 no.1
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• pp.31-39
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• 2008

We analyzed the current research trends of living modified organisms (LMO) by questionnaires in the interest of making biosaftey laws and policies in Korea. We executed a pre-survey at the Crop Functional Genomics 2004 conference and obtained LMO research information from 423 LMO research organizations, including 32 national research institutes, 314 universities, and 77 industries. We found that the total 59 kinds of hosts including 26 kinds of plants, 15 kinds of animals, and 18 kinds of microbes were used for LMO research and E. coli was the most common host. The risk of the most experimental hosts was below a biosafety level of 1 (73.8%) and 2 (25.9%). LMO development use purpose was implemented in various developmental uses: 51.3% in test and research use, 19% in health and medical use, and 12.9% in agriculture use. The experiment product, waste product, and products of host for LMO development were 327.2, 223.6, and 13.5 in number of plants; 280.6, 52.4, and 8.7 in number of animals; and $8.3\;{\times}\;10^{11}CFU$, $7.7\;{\times}\;10^{11}CFU$, and $6.5\;{\times}\;10^{11}CFU$ in microbes in 2004. The survey results about how to possess the LMO were very unreliable, because only 10.6% of the researchers returned the questionnaires. Consequently, we strongly suggest the scientific organizations as well as scientists should have more interests in biosafety of LMO research and an LMO biosafety management system should be developed for Korea's future biotechnology.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.403-410
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• 2007

A field experiment was conducted to investigate effects of application time and rate of biofertilizer alone and in combination with chemical NPK fertilizer on growth, yield and quality of rice. The biofertilizer used composted food waste as substrate and added with effective microorganism. The treatments included recommended NPK fertilizer(RF, $11-5.5-4.8kg\;10a^{-1}$), half recommended NPK fertilizer(HRF, $5.5-2.8-2.4kg\;10a^{-1}$), half recommended NPK fertilizer plus $250kg\;10a^{-1}$ biofertilizer(HRF+Bio 250) and $500kg\;10a^{-1}$ biofertilizer(HRF+Bio 500). The biofertilizer treatments were applied at 0, 5 and 10 days before transplanting(DBT). Grain yield of HRF+Bio 250 at 5 DBT($648.4kg\;10a^{-1}$) was statistically similar to the highest obtained in the RF($654.1kg\;10a^{-1}$). Tiller numbers at HRF plus biofertilizer treatments were already high during the maximum tillering stage, and were similar with that of the RF and higher than that of the HRF during heading stage. Likewise, ripening ratio at HRF plus biofertilizer treatments was similar with that of the RF and higher than that of the HRF. Furthermore, all the biofertilizer treatments improved protein content but reduced the amylose content and palatability compared to treatments with chemical NPK fertilizer alone. Thus, HRF+Bio 250 at 5 DBT can be used to save 50% chemical NPK fertilizer and at the same time obtain an improved rice grain yield and quality.

• Journal of Internet Computing and Services
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• v.15 no.5
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• pp.1-7
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• 2014

WireWireless sensor networks(WSNs) are generally comprised of densely deployed sensor nodes, which causes highly redundant sensor data transmission and energy waste. Many studies have focused on energy saving in WSNs. However, delay problem also should be taken into consideration for mission-critical applications. In this paper, we propose a BISA (Bio-Inspired Scheduling Algorithm) to reduce the energy consumption and delay for WSNs inspired by biological systems. BISA investigates energy-efficient routing path and minimizes the energy consumption and delay using multi-channel for data transmission. Through simulations, we observe that the BISA archives energy efficiency and delay guarantees.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.129-129
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• 2003

본 연구는 음식물 퇴비의 합리적인 시용량을 검증하고, 3년 연용에 의한 토양 변화 및 고추 생육과 수량에 미치는 영향을 평가하고 돈분퇴비를 시용한 대조구와 생육 및 품질 면에서 비교 분석하여 적정한 퇴비 시용량을 설정하기 위하여 실시하였다. 처리구는 1, 2, 3차 연도 모두 동일한 방법으로 무처리구, 대조구(2ton/10a의 돈분퇴비), 음식물 퇴비 2t, 4t, 6t, 8ton/10a을 사용한 처리구 등 6개를 두었으며 3반복, 난괴법을 이용하였다. 음식물 퇴비와 돈분 퇴비의 이화학적 특성을 분석한 결과, 음식물 퇴비의 경우 1차 연도는 유기물과 NaCl 모두 부산물 비료의 공정규격에 적합하였으나, 2차 연도는 유기물이, 3차 연도는 NaCl이 공정규격에 적합하지 않았다. 그리고 돈분 퇴비의 경우 수분함량이 약간의 차이를 보였으나 공정규격을 벗어나지는 않았다. 토양은 음식물 퇴비 시용량이 증가할수록 대부분의 화학적 특성이 증가하였고, 연용에 의해서도 유기물, 치환성양이온, NaCl 등의 양이 증가함을 보여 염류집적이 일어나고 있음을 확인할 수 있었다. 또, 음식물 퇴비 시용량증가에 따라 비중은 낮아지고 공극률이 증가하여 물리성 개선에 도움을 주었으나, 1, 2, 3차 연도를 비교해 보았을 때 큰 차이는 없었다. 고추의 생육과 수량에 있어서도 음식물 퇴비 시용량이 증가할수록 초기 생육이 저조하였으며, 그로 인해 수량이 감소하였다. 또한 3년 연용으로 인한 음식물 퇴비의 축적으로 수량의 감소와 품질 저하를 초래하였다. 음식물 퇴비의 연용에서 2ton/10a 이상의 시용은 수량의 감소를 초래하였다. 이러한 결과로 볼 때 음식물 퇴비를 2ton/10a 이하로 사용하면 큰 무리는 없겠지만 장기 연용은 삼가는 것이 좋을 것이라 판단된다. 따라서 음식물 퇴비를 다른 일반 퇴비 제조의 중간 원료나, 또는 혼합 사용하는 시험을 계속 진행 중에 있다.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.654-661
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• 2017

Recently, a low-impact development (LID) technic such as a wetland has been proposed as a Nature-friendly process for reducing pollutants caused by livestock wastewater. Therefore, the Daphnia magna toxicity was analyzed for livestock wastewater samples, to determine if a wetland system would also be effective in reducing this ecotoxicity. In the present study, acute D. magna toxicity was not significantly dependent on the presence and type of reed, nor type of media. However, when treated with construction wetlands, ecotoxicities decreased as well as TN, TP and COD concentrations. Therefore, it is considered that a construction wetland system with bio reeds and bio-media as well as general reeds would be effective to reduce the ecotoxicity of livestock wastewater. To apply a wetland system as the subsequent treatment process to a livestock waste water treatment facility, it is necessary to perform an integrated evaluation such as treatment efficiency and the ecotoxicity test for various characteristics of livestock wastewater.