• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.985-994
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• 2018

Bio-heavy oil for power generation is a product made by mixing animal fat, vegetable oil and fatty acid methyl ester or its residues and is being used as steam heavy fuel(B-C) for power generation in Korea. However, if the fuel supply system of the fuel pump, the flow pump, the injector, etc., which is transferred to the boiler of the generator due to the composition of the raw material of the bio-heavy oi, causes abrasive wear, it can cause serious damage. Therefore, this study evaluates the fuel characteristics and lubricity properties of various raw materials of bio-heavy oil for power generation, and suggests fuel composition of biofuel for power generation to reduce frictional wear of generator. The average value of lubricity (HFRR abrasion) for bio-heavy oil feedstocks for power generation is $137{\mu}m$, and it varies from $60{\mu}m$ to $214{\mu}m$ depending on the raw materials. The order of lubricity is Oleo pitch> BD pitch> CNSL> Animal fat> RBDPO> PAO> Dark oil> Food waste oil. The average lubricity for the five bio-heavy oil samples is $151{\mu}m$ and the distribution is $101{\mu}m$ to $185{\mu}m$. The order of lubricity is Fuel 1> Fuel 3> Fuel 4> Fuel 2> Fuel 5. Bio-heavy oil samples (average $151{\mu}m$) show lower lubricity than heavy oil C ($128{\mu}m$). It is believed that bio-heavy oil for power generation is composed of fatty acid material, which is lower in paraffin and aromatics content than heavy oil(B-C) and has a low viscosity and high acid value, resulting in inhibition of the formation of lubricating film by acidic component. Therefore, in order to reduce friction and abrasion, it is expected to increase the lubrication of fuel when it contains more than 60% Oleo pitch and BD pitch as raw materials of bio-heavy oil for power generation.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.549-557
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• 2006

The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.

• Korean journal of food and cookery science
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• v.25 no.2
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• pp.252-259
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• 2009

Ergosterol is the significant component of the cell wall of fungi. Its presence is regarded as evidence of fungi contamination in grain and other foods. Many studies on ergosterol detection have been carried out using chemical methods, but those methods required complicated pre-treatments and long analysis times. In this study, an amperometric biosensor was developed for fast and precise ergosterol detection. The biosensor system used the electron transfer of hydrogen peroxide produced from the reaction of ergosterol with cholesterol oxidase. The biosensor system consisted of a peristaltic pump, a syringe loading sample injector, an enzyme reactor, a fabricated flow-through cell containing a working electrode, a reference electrode and a counter electrode, and a potentiostat/recorder. The working electrode was prepared by coating modified multi-wall carbon nanotube (MWNT) on glassy carbon electrode. The $MWNT-NH_2$ coated glassy carbon electrode linearly responded to hydrogen peroxide in the range of $1{\times}10^{-5}{\sim}8{\times}10^{-5}$ M with a detection limit of $10^{-7}$ M in the basic performance test. The currents produced from the ergosterol biosensor showed the linearity in a range from $1.0{\times}10^{-6}$ M to $1.0{\times}10^{-5}$ M ergosterol.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.543-547
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• 2015

The cooling process referred to as Tempcore has been applied to produce a high-strength rebar. Excellent rebar with strength and weldability can be manufactured from mild steel without the addition of alloying elements by using the Tempcore process. However, there are limitations to evaluating the effect of various chemical compositions and cooling conditions within a site facility. In this study, we developed an apparatus to simulate the Tempcore process and obtained microstructures with a hardened surface layer, an intermediate region and a soft inner core. The experimental apparatus has been equipped with a cooler set that is the same as the site facility and consists of a pump line that supplies pressure of 12-13 bar and flow rate of up to $50m^3/h$. In accordance with the simulation result of steel grade SD400 that requires more than 400 MPa of yield strength, both the hardened area ratio and the hardness with respect to each cooling depth were found to agree well with the product.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.798-807
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• 2008

Due to economic impairment derived from metal corrosion of pumping station installed around coastal area, it was needed for related cause-effect to be investigated for understanding practical corrosion behavior and providing proper control. This research was thus carried out to determine whether the microbe can influence on metal corrosion along with its control in the laboratory. For this study, groundwater was sampled from the underground pump station(i.e. I Gas Station) where corrosion was observed. Microbial diversity on the samples were then obtained by 16S rDNA methods. From this, microbial populations showing corrosion behaviors against metals were reported as Leptothrix sp.(Iron oxidizing) and Desulfovibrio sp.(Sulfur reducing) Iron oxidizing bacteria were dominantly participating in the corrosion of iron, while sulfate reducing bacteria were more preferably producing precipitate of iron. In case of galvanized steel and stainless steel, iron oxidizing bacteria not only enhanced the corrosion, but also generated its scale of precipitate. Sulfate reducing bacteria had zinc steel corroded greater extent than that of iron oxidizing bacteria. In the inactivation test, chlorine or UV exposure could efficiently control bacterial growth. However as the inactivation intensity being increased beyond a threshold level, corrosion rate was unlikely escalated due to augmented chemical effect. It is decided that microbial corrosion could be differently taken place depending upon type of microbes or materials, although they were highly correlated. It could be efficiently retarded by given disinfection practices.

• Journal of Biomedical Engineering Research
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• v.38 no.2
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• pp.62-73
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• 2017

To identify a solution for the restricted availability of healthy lungs and the high risk of immune rejections following organ transplantation, tissue engineering techniques for culturing lungs have been studied by many research groups. The most promising method for culturing lungs is the utilization of a bio-scaffold that was prepared using harvested organs from human donors or other animals by removing their original cells. In this study, a pulsatile perfusion pump was used to alleviate the cell removal effect with the high fluid-dynamic power of the perfusion stream during the decellularization process, while other conventional studies focused on chemical methods to identify efficient detergents. The purpose of this study was to analyze the developed device by using energy equivalent pressure (EEP), which is an indicator of pulsatility, to understand the characteristics of pulsatile energy transmitted according to the load size by using the artificial model and compare it with the measured EEP. The pulsatility of the device can be estimated with the concept of fluid-dynamic energy during a particular constant time period or fluid-dynamic power represented as EEP and EEP increment. Because the measured EEP of perfusion flow during decellularization can be changed by the amount of fluid leakage and the degree of clogging in the capillary vessels, EEP should be measured to determine whether the decellularization is progressing without problems. The decrement of EEP caused by the high perfusion resistance was observed from some experimental results that were obtained with artificial models. EEP can be used to monitor the decellularization process after analyzing the varying EEP according to the amount of load. It was confirmed that the EEP was maintained at a high level in the experiment using the harvested lungs from 12-13-week-old rats. In addition, it was confirmed that the cell removal time was faster than when continuous perfusion was performed. In this study, pulsatile power delivered to the lungs was measured to monitor the process of cell removal, and it serve as the evidence for efficient decellularization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.355-362
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• 2016

The pipe material is selected according to the physical and chemical properties of the fluid flowing within it. Because the fluid used in fire extinguish systems is water, the various foreign substances dissolved in it cause scale to form on the pipe wall and accelerate the corrosion and aging of the pipe itself. This results in an increase in the friction loss and eventually degrades the efficiency of the pump. The use of CPVC (Chlorinated Poly-Vinyl Chloride) pipes was confirmed to reduce the friction loss compared to conventional steel pipes in the design and construction stages. The friction loss was found to be 76.64MPa with a C-value of 120 for the steel pipe and 50.72 MPa with a C-value of 150 for the CPVC pipe in an actual apartment construction environment. It was confirmed that the friction loss was improved by about 34% when using the CPVC pipe. When the steel and CPVC pipes were employed in the construction, the construction costs were 1,585,158 and 931,842 won, respectively. Therefore, it was shown that the construction cost was reduced by about 41%. We investigated the safety of the fire extinguishing system and the improvement in the economic performance due to the reduction in the total installed capacity by studying practical applications in the field.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.139-152
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• 1985

본 NEWASA 지역의 접수관정관개 개발에 따른 정제성분석 연구는 IBRD-EDI와 INDIA RESERVE BANK의 College of Banking이 공동주최한 Trainers Trining for Rural Finance (1985. 1.19-3.1)의 일환으로 1985. 2. 14-19 까지 NEWASA BLOCK에 대한 정수정관개의 경제적 효율성을 평가하기 위하여 농가조사를 실시하였고, 그 분석결과를 정리한 것으로 농지는 넓으나 농업용수가 부족한 본 지역은 빈곤과 저생산성 농촌잠재 실업을 특징으로 하고 있다. 농촌소득의 제고와 농촌실업의 고용확대는 전 인구의 80% 이상이 농민인 본지역뿐만 아니라 선언도 경제개발의 중심과제이다. 호당 6 acres 규모의 관개가 가능한 Dug-well Irrigation Development는 연평균 강우량이 650m/m에 불과한 인도의 Plateau 지역에서는 농촌빈곤과 실업문제의 해결, 토지 이용율제고를 통한 토지생산성 향상등 농촌경제개발의 중심과제로서 인도정부가 추진하는 핵심적인 농업정책이다. 본 지역의 농가호당 평균 소유농지연적은 8.67 acres(3.5ha)로써 모두가 Rainfed farming으로 현재 본 지역의 관개율은 17.5%에 불과하다. 농작물은 Jowar라고 하는 내한성 작물이 재배되며, 관개 조건하에서는 Jowar, Wheat, Sugarcane이 재배된다. With and Without Dug-Well Irrigation 조건하에서 각 작물별 ha당 생산성을 보면 Jowar는 0.86 ton/ha에서 2.22 ton/ha으로 증산되고 Wheat는 2.96 ton/ha, Sugarcane는 98.8 ton/ha이 생산된다. 한편 Dug-well Irrigation 전후의 농가소득의 변화를 보면 시행전의 4,275Rs가 되어 4배의 농가소득이 증가된다. 이와 같은 농업소득을 획득하기 위해서는 Dug-well에 대한 Initial Investment로서 33,400Rs(2,137,600원)이 투자되어야 하는데 종류별 융자 기간을 보면 Dug-well 15년(95%융자) Pump Set 9년(95%융자), Woriking capital 1년이며 인도의 Union Bank에서 융자하고 있다. 결론적으로 이러한 Dug-well Irrigation Development에 따른 IRR는 Before Financing시에는 29%이며 After Financing 시에는 24%이고 B/C ratio는 두경우에 있어 1.89, 1.24를 각각 나타냈다. 따라서, 본 사업은 재무적인 측면 즉 농가소득증대와 농촌고용증대 및 토지이용면에서 타당성이 크며 Dug-well Irrigation은 인도의 농업성장 및 경제개발의 관건으로 생각된다. 한국의 수리개발 기술 및 농업기술(Bio-chemical, Mechanical & Hydrological Technology)이 이전된다면 보다 괄목할 만한 농업발전이 이룩될 것을 생각된다.

• Journal of Environmental Health Sciences
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• v.41 no.4
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• pp.241-248
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• 2015

Objectives: This study was conducted to provide scientific and effective information on phytoncides, which are associated with forest healing, and to activate recreational forests. Methods: The target sites were natural recreation forests, a forest park and an arboretum, and the control sites were three urban parks. The samples were collected at a volume of 6.0 L and a flow rate of 0.1 L/min for one hour using a low volume pump and the solid adsorbent sampling method. The phytoncide compounds adsorbed in the Tenax TA tube were analyzed by a automatic heat desorption unit and GC-MS. Results: By type of recreational forest, the annual concentrations of phytoncide (monoterpene) for the forest park showed the highest concentration with $1.450{\mu}g/m^3$, while those for the arboretum showed the lowest concentration at $0.892{\mu}g/m^3$, and thus the concentration of the forest park was approximately 1.6 times higher than the arboretum. The season showing the highest concentration of phytoncides was summer (June) and the forest park was the highest among the recreational forests. The concentrations of major components for phytoncide showed in descending order: ${\alpha}-pinene$, ${\beta}-pinene$, camphene, 3-carene and limonene. The seasonal concentration of ${\alpha}-pinene$, camphene and ${\beta}-pinene$ by type of recreational forest increased in April, which is characterized by low temperature and humidity, and the seasonal concentration of camphene decreased with higher humidity. The meteorological factors which had the high correlation with the concentration of total terpene were temperature and humidity. $CO_2$ and $O_2$ showed an inverse correlation. Conclusion: The major components of phytoncide were ${\alpha}-pinene$, ${\beta}-pinene$, camphene, 3-carene and limonene in descending order of concentration. Further and systematic study on the chemical nature of individual phytoncides, and on the effect of phytoncides on humans needs to be performed.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1109-1116
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• 2002

This study analyzed concentrations of volatile organic compounds (VOCs) produced from incineration of papers at $600^{\circ}C$. The papers used in this study included A4 papers (new, printed with ink-jet, printed with carbon), newspapers (printed with bean oil, printed with a general newspaper ink), packaging box, document envelope, single-use paper cup, and cosmetic tissue. Papers were heated from room temperature upto $600^{\circ}C$ providing air inside of the electric furnace and then they were oxidized for 80 minutes at $600^{\circ}C$ maintaining the same air supply. VOCs emitted from the incineration process were sampled using an air sampling pump and bags for 160 minutes and then the components and concentrations of the VOCs were analyzed by a CC-MS. The most prominent chemical structure of the Vous identified from incineration of the papers was furans and then furans were followed by aromatics and aliphatic alkenes. About 40% of the identified VOCs contained double bonds, which have relatively a high ozone (ground level) formation potential, within their molecular structure. Also, some cancer suspecting compounds like benzene, dichlorormethane and chloroform were identified.