• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.6-12
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• 2005

Contamination of soils and groundwater by leakage of petroleum compounds from underground storage tanks (USTs) has become great environmental issues. Conventional methods such as soil vapor extraction (SVE) used for the remediation of unsaturated soils contaminated with volatile organic compounds might not be applied for the removal of semi-volatile organic compounds such as diesel fuels and PCBs, which have low volatility and high hydrophobicity. The objective of this study is to develop a hot air injection method to remove semi-volatile compounds. Additionally, operation parameters such as temperature, air flow rate, and water content are evaluated. Experimental results show that diesel ranged organics (DROs) are removed in the order of volatility of organic compounds. As expected, removal efficiency of organics is highly dependent on the temperature. It is considered that more than $90\%$ of organic contaminants whose carbon numbers range between 17 and 22 can be removed efficiently by the hot air injection-extraction method (modified SVE) over the $100^{\circ}C$. It is also found that increased air flow rate resulted in high removal rate of contaminants. However, air flow rate over 40 cc/min is not effective for the operation aspects, due to mass transfer limitation on the volatilization rate of the contaminants. The effect of the water content on the decane removal is minimal, but some components show large dependence on the removal efficiency with increasing water content.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.57-64
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• 1999

The purpose of this study is to establish effective conditions for controlling $CH_4$, $N_2O$ emission from organic Waste / wastewater treatment processes. Continuous and batch experiments were conducted to treat the micro algae from polluted and eutrophicated lakes through the thermophilic oxic process. The microalgae used were mainly Microcystis sp.(collected from eutrophic lake) and Chlorella sp. (cultured in laboratory) Wasted cooking oil was added by aid-heating source. Physico-chemical components of sludges and microalgae were analyzed. In batch experiments, air supply was changed from 50ml/min to 150ml/min. The temperature. water content and drained water were affected by the air flow rate at initial stage. However, there was almost no influence of air flow rate on them in middle and last stages. At air flow rate of 100ml/min, the degradation rate of organic material was higher than that at other air flow rates. $CO_2$ concentration in exhaust was proportional to the strength of aeration, especially at initial stage when degradation was active. $CH_4$ with low concentration was detected only at starting stage when air diffusion was not enough. $N_2O$ production was not affected by variation of air supply. In continuous experiments no matter what the dewatering methods (with PAC and without PAC) and media (wood chip and reed chip) were changed, $N_2O$ was almost not affected by variation of injected air. Result showed that the reed chips using for lake purification could be used as media for thermophilic oxic process in lake and marshes area. $CO_2$ concentration was not so much affected by the change of dewatering methods and media types. $CH_4$ was not detected in the experimental period. So it can be shown that the thermophilic oxic process had been well operated in wide handling conditions regardless of media and dewatering methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.69-75
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• 1974

This experiment was conducted to investigate the influence of different amount of nitrogen and deficiency of soil moisture on yield components of soybean. Soybean were seeded on 1/2000a wagner pot. Deficiency of soil moisture was treated at each growth atage of soybean. 1.In case of deficiencyt of soil moisture at the flowering time in the plot of non-nitrogen(NO D3), the growth duration of soybean was shortened about three to four days. 2. The leaf area was greatly affected by the influence of both treatments till 49days after germinating. 3.The increase of stem height, stem doameter,number of branches and lengeh of the branches came to an end about 70 days after seeding. These growing condition of tje soybean were lowest the plot of No D$_1$,in which the frowth of the soybeans were poor at the early stage. 4.The number of pods was not increased by the increase of fertilizing nitrogenous fertilizer. The number of pods was much decreased by the influence of soil mousture deiciency, and under this condition, the proportion of main stem pods and two or three grain pods was high. 5.The 3rd and 4h nodes and the 10th to 12th nodes from bottom had more pods than the other nodes had, but of the plants had grown well, they had more pods on the 3rd and 4th nodes, but if the plants had grown poorly, they had more pods on the 10th to 12th nodes. 6.The content of protein in the soybean was low at the plit of N。D$_4$which had not heavy weight of 100 grains, and the content of oil in the soybean was low in the plot in which each plant had a small number of grains.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.194-199
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• 2005

The principle of vortex cyclone was applied to enhance the treatment efficiency of waste air streams containing particulate matters, phenol, and others. Adsorption, condensation, and/or coagulation could be induced at low temperature zone formed by Joule-Thomson expansion as the pressurized air and pulverized activated carbon were introduced at the tangential direction into the cyclone system applied with the coaxial funnel tube of vortex cyclone. Easily condensible vapors were adsorbed and/or condensed forcibly on coagulated or condensed materials which were formed as cores for coagulation or condensation by themselves or on pulverized activated carbons. These types of coagulation or condensation rates were rapidly promoted by increase in their diameter. The maximum removal efficiency obtained from this experiment for the removal of carbon dioxide and phenol was about 87.3 and 93.8 percent, respectively. Phenol removal efficiency was increased with the relative humidities and enhanced by pulverized activated carbon added. The Joule-Thomson coefficients were increased with the pressure of air injected in the range of the relative humidities between 10% and 50%. It is believed that the moisture, particulate matters, and the pressure of the process air introduced could control the removal efficiency of VOCs.

• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.5-16
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• 2012

The second scientific antarctic station of South Korea is under construction at Terra Nova Bay located in eastern Antarctica. Ground condition in the Antarctica is frozen in general, but there are seasonal frozen grounds with active layers sporadically. When the active layer is frozen, frost heaving occurs that might cause the differential movement of frozen ground and the failure of structures. Therefore, it is necessary to determine the frost heaving susceptibility of soils at Terra Nova Bay before starting antarctic station construction. This study presents experimental investigation of the frost heaving susceptibility of soil samples with variation of particle sizes and unfrozen water contents. The soil samples were taken from five different locations at Terra Nova Bay and physical properties, unfrozen water content, and frost heaving tests were performed. For the frost heaving tests, soil specimens were frozen with constant freezing temperatures at the top and with drainage at the bottom in order to stimulate the frost heaving. The frost heaving tests provide volume expansion, volumetric strain, and heaving rate which can be used to analyze the relationship between the frost heaving vs. particle size and the frost heaving vs. unfrozen water content. Experimental results show that the more the fine contents exist in soils, the more frost heaving occurs. In addition, the frost heaving depends on unfrozen water content. Experimental data can be used to evaluate the frost heaving susceptibility of soils at the future construction site in the Antarctica.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.25-33
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• 2018

Renewable energy has been of interests in the area of modern alternative fuels. Biogas is produced in waste landfill sites through anaerobic digestion processes, including hydrolysis, acidogenesis, organic acid fermentation (acetogenesis), and methane fermentation (methanogenesis). High contents of fine dust and moisture limited its utilization for direct combustion, town gas and vehicle fuel. Thus, this study proposed a new design for a cooling device using a centrifugal cyclone for simultaneous removal of fine dust and moisture as a pretreatment in the purification processes. A heat exchanger and an ID fan, which are installed inside and outside of the cyclone, in order to cool the humid gas below the freezing point and form a foggy mist. Such an atmosphere enhanced to capture fine dust as recirculating the cold mist flow. The water removal rate was 80.8% at a relative humidity of 95%, and the particle removal efficiency was 98.3% for $2.5{\mu}m$. Simultaneous removal efficiency was 70.8% and 99.6% for particle and moisture respectively.

• Journal of Mushroom
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• v.13 no.3
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• pp.233-236
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• 2015

This report is the result of devising a method for utilizing the device of the load cell to maintain a constant water content of the medium every day to prepare a cultural substrates with the mixer for growing mushrooms bottle cultivation. A load cell was device under the medium mixer. It is developed when the device reaches the weight calculated as amount of substrate bottled and number of the bottle, it is automatically terminated by water injection. In addition, measuring the water content of each medium and the total weight of the medium reaches the target moisture content were calculated by using the program Cheong et al. (2015). Enter the total weight of the medium on the display unit of the load cell, when starting the water supply to reach the weight-based mixing media, the water supply is stopped. This method can improve the convenience by reducing the user's trouble in repeated work medium prepared by automating water supply. The suitable moisture content of the mixed medium for some kind of mushroom can be improved by the composition accuracy. And mycelial culture period, primordial period, mushroom growing period is maintained even of the medium can be produced stably. Therefore, it is possible to achieve a stable management of the mushroom farm according to mushroom quality and quantity stable throughout the year.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.225-231
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• 2001

This study was conducted to find out the optimal aeration rates for minimizing odor emission and for increasing biological activities during composting of livestock manure in the enclosed bench-scale reactor system. It was treated with the mixture of poultry manure and sawdust controlled the initial water content of 60%, then aerated continuously at four different aeration rates (0.1, 0.2, 0.4 and 0.6 L/min/kg dry-solids). The average emitted concentration of ammonia in 0.6 L/min/kg dry-solids during composting reached the level of 40% in comparison with that of 0.2 L/min/kg dry-solids. In cases of sulfur compounds such as hydrogen sulfide, methylmercaptan and ethylmercaptan, their concentrations decreased with increasing aeration rates and the emission time was shortened. But they didn't detect in the treatment of 0.6 L/min/kg dry-solids. The biological activity for composting showed a trend of increasing as aeration rates increased. The treatment of 0.6 L/min/kg dry-solids gave the highest biological activity and the best compost quality.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.401-401
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• 2012

유기발광소자는 유연 소자로의 적용, 자체 발광 등의 장점으로 차세대 디스플레이로서 각광받고 있다. 하지만 유기발광소자는 유기물을 발광층으로 하고 있기 때문에 수분에 취약하다는 단점이 있다. 그래서 봉지 기술(encapsulation)을 필요로 한다. 널리 알려진 방법으로는 유리로 소자를 감싸고 내부에 흡습제를 충진하여 수분 투습을 줄일 수 있다. 하지만 위 기술을 사용할 경우 유기발광소자의 장점인 유연 소자의 적용이 어렵다. 따라서 박막 봉지 기술을 이용하면 보다 얇은 두께의 소자 제작이 가능하고 유연 소자의 적용 역시 가능해진다. 박막 코팅을 이용한 봉지 기술 중 화학적 증착법(Chemical Vapor Deposition, CVD)이나 물리적 증착법(Physical Vapor Deposition, PVD)을 이용하는 방법이 널리 알려져 있지만 원자층 증착법(Atomic Layer Deposition, ALD)을 이용하면 보다 낮은 두께의 치밀한 박막을 제작 할 수 있다. 본 연구는 원자층 증착법을 응용한 분자층 증착법(Molecular Layer Deposition, MLD)을 이용하여 Trimethylaluminum과 Ethylene glycol을 순차적으로 주입함으로써 Alucone 유기 박막을 제작하고 유기발광소자의 봉지 기술로의 적용을 위해 투과 방지막 특성에 관하여 분석했다. 박막 봉지 기술로서 적용하기 위해 제작된 투과 방지막은 원자층 증착법으로 Al2O3무기 박막을 제작하고 분자층 증착법으로 Alucone 박막을 순차적으로 증착하였다. 이를 Ca를 이용하여 전도도를 측정하고, 투습도를 계산하여 투과 방지막 특성을 분석하였다. Alucone 박막은 우수한 투과 방지막 특성을 가지지는 못하지만 적층 구조로 제작함으로써 두 쌍의 Alucone/Al2O3일때, $6.07{\times}10^{-2}g/m^2day$의 투습도를 보여주고 있다. Alucone 박막의 존재는 수분이나 산소의 투과 경로 길이를 늘려줌으로써 Alucone/Al2O3 박막의 투과방지 특성이 향상되는 것으로 사료된다.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.472-481
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• 2000

This experiment used the enclosed bench-scale reactors was conducted to find out optimal aeration rate for reducing the emission of odors and producing the good-quality compost with the mixture of dairy manure and rice straw. The reactors with gas sampler were aerated at four different rates of 0.09, 0.18, 0.90 and $1.79l\;min^{-1}kg^{-1}$dry solids for 574 hours. The oxygen content within composting pile instantly decreased after aeration. Oxygen limitation(below 15%) in the treatments of $0.90l\;min^{-1}kg^{-1}$ and less was exponentially negative relationship with aeration rates and in the range of 35 to 300 hours after aeration. However, the treatment of $1.79l\;min^{-1}kg^{-1}$ didn't show the oxygen limitation. The oxygen consumption rate and the cumulative amount of oxygen consumed by different aeration rates was ranged in $0.80{\sim}1.57O_2g\;h^{-1}\;kg^{-1}VS^{-1}$, $460{\sim}900O_2g\;kg^{-1}VS^{-1}$, respectively, and they were high in the order of 0.90, 1.79, 0.18, $0.09l\;min^{-1}kg^{-1}$. The maximum oxygen consumption rate was estimated in the range of $1.2{\sim}1.3lmin^{-1}kg^{-1}$. The emission concentrations of sulfur compounds such as hydrogen sulfide, sulfur dioxide and methylmercaptan were remarkably high in the initial composting time. Then they were rapidly decreased with the passing of composting time and clearly with increasing aeration rates. Their average concentrations were in the range of 0.03~2.18, 0~0.50, $0.07{\sim}3.38mg\;kg^{-1}$, respectively and high in the order of methylmercaptan, hydrogen sulfide, and sulfur dioxide. Concentrations of sulfur compounds emitted from composting showed exponentially negative relationship at 1% statistically with the oxygen concentration. It was estimated that hydrogen sulfide and methylmercaptan suddenly increased in the level of 5% oxygen concentration and below, that they were little emitted in 15% and over but sulfur dioxide was emitted in the level of 20% oxygen.