• Environmental Engineering Research
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• 제12권4호
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• pp.157-175
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• 2007

The membrane biofilm reactor (MBfR) creates a natural partnership of a membrane and biofilm, because a gas-transfer membrane delivers a gaseous substrate to the biofilm that grows on the membrane's outer wall. $O_2$-based MBfRs (called membrane aerated biofilm reactors, or MABRs) have existed for much longer than $H_2$-based MBfRs, but the $O_2$-based MBfR is a versatile platform for reducing oxidized contaminants in many water-treatment settings: drinking water, ground water, wastewater, and agricultural drainage. Extensive bench-scale experimentation has proven that the $H_2$-based MBfR can reduce many oxidized contaminant to harmless or easily removed forms: e.g., ${NO_3}^-$ to $N_2$, ${ClO_4}^-$ to $H_2O$ and $Cl^-$, ${SeO_4}^{2-}$ to $Se^0$, and trichloroethene (TCE) to ethene and $Cl^-$. The MBfR has been tested at the pilot scale for ${NO_3}^-$ and ${ClO_4}^-$ and is now entering field-testing for many of the oxidized contaminants alone or in mixtures. For the MBfR to attain its full promise, several issues must be addressed by bench and field research: understanding interactions with mixtures of oxidized contaminants, treating waters with a high TDS concentration, developing modules that can be used in situ to augment pre-denitrification of wastewater, and keeping the capital costs low.

• 한국수자원학회논문집
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• 제34권6호
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• pp.725-733
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• 2001

본 연구에서는 모형배수지를 이용하여 유출량의 변동여부와 도류벽의 설치여부에 따른 유출수의 잔류염소농도의 변화를 추적하였다. 모형배수지의 실험결과를 고찰해 보면, 유출량을 변동시킨 경우에 있어서 도류벽이 없을 때와 도류벽이 2개 있을 때, 유출수의 평균 잔류염소농도의 차이가 유출량을 일정하게 유지한 경우에 비하여 줄어 들었다. 이는 유출량 변동의 영향에 의한 것으로 유출량의 변동이 심한 배수지에 있어서는 유출량의 변동이 심하지 않은 정수지에서 보다는 도류벽 설치의 효과가 작은 것으로 판단된다.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1373-1383
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• 2001

The desulfurization characteristics of anthracite in a bench scale pressurized fluidized bed combustor are investigated. The coal used in the experiment is domestic anthracite from Kangwon Taeback area. The desulphurization experiment is performed with limestone from Chungbuk Danyang. The pressure of the combustor is maintained at 6 atm, and the combustion temperatures are 850, 900, and 950$\^{C}$. The superficial gas velocities are 0.9, 1.1, and 1.3 m/s. The excess air ratio is varied from 5 to 35%. The Ca/S mole ratios are 0.5, 1.5, 2.5 and 4.5 mole. All experiments are executed at 2m bed height. Consequently, SO$_2$ concentration in the flue gas is increased with incresing bed temperature and superficial gas velocity. However SO$_2$ concentration is decreased with incresing excess air ratio and Ca/S mole ratio.

• 멤브레인
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• 제12권3호
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• pp.151-157
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• 2002

본 연구는 하수를 공업용수로 재이용하기 위한 분리막 시스템 적용에 관한 연구이다. 정밀여과와 역삼투시스템으로 구성된 bench scale 실험장치를 이용하여 하수처리장 현장에서 실험을 수행한 결과, 정밀여과 시스템은 이온성분은 제거할 수 없었으나 SS를 70% 이상 처리할 수 있어 처리수는 직접냉각수로 재이용이 가능하였다. 그리고 역삼투 시스템은 SS는 물론 이온성분도 95% 이상 제거할 수 있어 처리수는 간접냉각수 및 제품세척수로 사용이 가능하였다. $100 m^3$/일 용량의 pilot Plant를 제작하기 위해서는 정밀여과 모듈은 20개, 역삼투 모듈은 12개가 필요하였다.

• 자원리싸이클링
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• 제12권2호
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• pp.36-44
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• 2003

전구용 필라멘트 제조 공정에서 발생되는 Mo함유 폐산 내에 암모니아 가스를 취입하여 유가금속인 Mo를 암모늄테트라몰리브데이트($_3$.2NH$4MoO_3$.$H_2$O) 형태로 침전 회수하고, 여과 후 발생되는 중화 여액을 활용하기 위한 연구를 수행하였다. 암모니아 중화법을 이용한 Mo 회수공정에 있어 다양한 공정 변수들에 의한 제품의 회수율, 순도, 입도 등 특성을 평가하였으며, 그 결과로부터 Mo 염의 회수율 99.5% 이상, 순도 99.5% 이상을 확보하기 위한 최적 조업조건을 도출하였다. Bench 및 Pilot규모의 실험을 통하여 상업화 가능성을 확인하였으며, 폐산의 중화반응 후 발생된 여액은 엽면시비용 액상 복합비료의 원료로 사용 가능함을 확인하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권3호
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• pp.82-93
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• 2014

A starch ball was devised to conveniently supply carbon source to indigenous microorganisms and to enhance biotransformation of explosive compounds(TNT and RDX) in the sediments of settling basins installed in military shooting ranges. To identify optimum dose/sediment ratio for degradation of explosives in the basin, a series of bench scale settling basin experiments were performed for 30 days while monitoring supernatant pH, DO, concentrations of nitrite, nitrate, sulfate, explosive compounds, and acute toxicity measured by bacterial luminescence. Addition of starch ball induced changes in oxidation conditions from oxic to anoxic in the benthic zone of the basin, which resulted in subsequent reductive degradation of both TNT and RDX in the liquid and solid phase of basin. However, fermentation products of excess starch, acetic acid and formic acid, caused acute toxicity in the liquid phase. The optimum ratio of starch ball/sediment for explosive compounds degradation by inducing changes in bio-geochemical environments without increase in acute toxicity, was found to be 0.009~0.017.

• 수산경영론집
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• 제41권3호
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• pp.129-151
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• 2010

This study is to analyze the efficiency of Korean fishing ports using DEA. First, the study calculated the efficiency scores based on a CCR-BCC framework and hence technical, pure technical, and scale efficiency scores are seperated for the 38 fishing ports under study. The Average of technical, pure technical, and scale efficiency are turned out to be 0.6834, 0.8582, and 0.7774 respectively. The 15 fishing ports are fully efficient under the constant returns to scale while 21 fishing ports under the variable returns to scale. Second, the super efficiency scores are also calculated under the radial model without the consideration of slacks. The highest score is turned out to be 4.4984 for the P16 fishing port with the average score of 0.9652 for the entire fishing ports. Nevertheless, P16 fishing port has showed up only once as a reference set. On the other hand, P34 fishing port has showed up 11 times as a reference set, which scored the second highest score of 2.9815. Finally the super efficiency scores are calculated under the non-radial model with the explicit consideration of slacks. Now the P34 fishing port scored the highest score of 2.3424 with even 15 times referred to a bench-mark. Therefore the importance of P34 fishing port is emphasized once again on the field of bench-marking for the efficiency of fishing ports. When the targets for the input factors to improve the efficiency of each DMU are calculated the area of fishing port needs the most adjustment to be reduced for 40.36% on the average, while the cosignment sales area does the least adjustment for 13.70%.

• Tribology and Lubricants
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• 제18권4호
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• pp.305-311
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• 2002

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. A braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two types of brake with different sizes in stop and hold braking modes. Plasma spray coating technique was also used to coat the discs with ceramic powder. During the test four commercial brake pads were coupled with discs. Ceramic coated discs showed good stability in friction coefficient at high speed and high energy braking conditions. But they caused large wear loss of pad mass compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc. it showed fluctuating friction coefficient at high speed but small wear loss of pad mass compared with ceramic coated discs.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.97-107
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• 1998

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. Braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two sizes of brake discs in stop and hold braking modes. And Plasma spray coating technique was used to coat ceramic powder on the discs. In the test four commercial brake pads were coupled with discs. Ceramic coated discs had shown good stability in friction coefficient at high speed and high energy braking conditions. But they caused large pad mass wear loss compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc, it had shown fluctuating friction coefficient at high speed but a fittie pad mass wear loss compared with ceramic coated discs.

• 한국정밀공학회지
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• 제24권6호
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• pp.138-145
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• 2007

Among various rapid prototyping processes, stereo-lithography process which can manufacture transparent prototype is known to be the greatest in the form & dimensional accuracy and surface roughness. In this paper, bench mark tests of 4 stereo-lithography-type rapid prototyping apparatus were carried out using transparent materials. The test includes measurement of mechanical properties, form accuracy, building speed and manufacturing cost. It was observed that ViperPRO of 3D systems is advantageous in the mechanical properties and building speed, RM600011 of CMET in sub-milli scale form accuracy and manufacturing cost, and relatively economical Eden500V of Objet is great in tensile strength at room temperature.