• 한국물환경학회지
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• 제31권3호
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• pp.235-240
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• 2015

To evaluate the unit load generation and discharge, pig cage test was conducted. Feed intake, drink amount, and urine generation increased growth stage (heavy weight) of the pig more great. However, the sum of the urine and manure did not show a significant difference in the growth stages of pigs. Because of the limit of the experiment, e.g., research period, high pigpen temperature, breed-related stress and etc., it could not be derived the results of the four seasons. Therefore, in order to generalize the results, the feed intakes were calibrated using a NRC (National Research and nutritional requirements of pigs from the Commission) standards. The finalized unit load generation and generation amounts of manure and urine were estimated at BOD 104.1 g/head/d, T-N 21.2 g/head/d, T-P 4.9 g/head/d, manure 0.96 L/d, urine 1.66 L/d with consideration of revised feed intake. Compare to the former research results of MOE (Ministry of Environment, 1999) and NIAS (National Institute of Animal Science, 2008), the generation amounts of manure and urine were similar to the NIAS's values. In case of unit load generation, BOD and T-N were almost similar in all of them. However, the T-P unit load generation of MOE was more difference, e.g., 2.5 times high, compare to this study.

• Mass Spectrometry Letters
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• 제8권3호
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• pp.59-64
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• 2017

In clinical diagnosis, it's well known that the abnormal level of uric acid (UA) in human body is implicated in diverse human diseases, for instance, chronic heart failure, gouty arthritis, diabetes, and so on. As a primary method, an isotope dilution mass spectrometry (IDMS) has been used to obtain the accurate quantity of UA in blood or serum and also develop the certificated reference material (CRM) so as to provide a SI-traceability to clinical laboratories. Due to the low solubility of UA in water, an ammonium hydroxide ($NH_4OH$) has been considered as a promising solvent to increase the solubility of UA that enables the preparation of both UA and its isotope standard solution for next IDMS-based absolute quantification. But, because of using this $NH_4OH$ solvent, it gives rise to the unwanted degradation of UA. In this study, we sought to optimize condition for the stability of UA in $NH_4OH$ solution by varying the mole ratios of UA to $NH_4OH$, followed by ID-LC-MRM analysis. In addition, we also inspected minutely the effect of the storage temperatures. Additionally, we also performed the quantitative analysis of UA in the KRISS serum certificated reference material (CRM, 111-01-02A) with diverse mixing ratios of UA to $NH_4OH$ and then compared those values to its certification value. Based on our experiments, adjusting the mole ratio of 1/2 ($UA/NH_4OH$) with the storage temperature of $-20^{\circ}C$ is an effective way to secure both the solubility and stability of UA in $NH_4OH$ solution for next IDMS-based quantification of UA in serum.

• 한국농공학회지
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• 제40권3호
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• pp.83-92
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• 1998

Field experiment was performed from August 1996 to January 1998 to examine the applicability of constructed wetland system for wastewater treatment in rural area. The pilot plant was installed in Kon-Kuk University and the school building septic tank effluent was used as an influent to the treatment basin. Hydraulic loading rate was about 0.1 6$0.16^3/m^2$ day and theoretical detention time in the system was 1.38 days. The treatment basin was composed of sand and reed. The influent DO concentration was low and many cases close to zero, but effluent concentration was higher than the influent which implies that oxygen was supplied naturally. The average concentration of influent BOD was 126mg/L, and with average removal rate of 69 % the average effluent concentration was 4Omg/L which satisfied the effluent water quality standard for the system of interest. The average influent concentration of COD was 2Olmg/L and average effluent concentration was 75mg/L with average removal rate of 60%. The performance of BOD and COD tends to deteriorate in the low temperature, and appropriate action needs to be taken during the cold winter time for stable operation. The average influent concentration of SS was 5Omg/L, and effluent was 1 1mg/L with average removal rate of 76% which satisfied the effluent water quality standard for the system of interest. The results for the regulated components, SOD and SS, from the experiment showed that constructed wetland system can meet the effluent water quality standards. The average influent concentration of total phosphorus was 25.6mg/L and average effluent concentration was 7.8mg/L with average removal rate of 63%. Not like the performance of the above components, average nitrogen removal rate was only 11.2% which is not satisfactory. Although, nitrogen is not regulated at this moment, it can cause many environmental problems including eutrophication. Therefore, nitrogen removal efficiency should be improved for actual application. From the result of the field experiment, constructed wetland system was thought to be an appropriate alternative for wastewater treatment in rural area.

• 한국농공학회지
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• 제42권4호
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• pp.96-105
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the performance of constructed wetland system for wastewater treatment in rural area. The constructed wetland system was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the treatment basin. The treatment basin was composed of sand bed with planted reed. From August 1996 to June 1998 the hydraulic loading rate was fixed with about 15.63cm/day and theoretical detention time was 1.38 days, and from July 1998 to December 1999 the hydraulic loading rate was about 6.25cm/day and theoretical detention time was 3.5days. It worked continuously even during winter time, and the sewage flowed without freezing even when average daily air temperature was below -1$0^{\circ}C$. Average removal rate of BOD , COD, and SS was about 70%, T-P removal rate was about 50.8% , and T-N removal rate was 23.9%. The reason for poor T-N removal might be due to high influent concentration and short retention times. At the later years BOD and COD removal rates were increased , and SS and T-P removal rates did not change significantly , but T-N removal rates were decreased. The effluent of the wetland system often effluent water quality standards for sewage treatment plant, therefore, further treatment would be required if the effluent need to be discharged to the public water. Wetland system involves relatively large land area and could be suitable for rural area. Therefore, utilization of reclaimed sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage in rural area.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.52-57
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• 2005

The increasing automobiles continue to cause air-pollution problem s worse than ever. In fact, many automobile research are involved in how to reduce exhaust emissions effectively specially in $NO_X$ and PM to comply with stringent emission standards, Euro V. This research emphasized on the development of continuous regeneration DPF technology which was one of promising removing technology of particulate matters because of its comparability and high applicability. In addition, this research discussed on some design points of view through correlation study by com paring the experimental data with computational results by the introduction of commercial codes such as CFD-ACE+ and KIVA-3V. The numerical simulation on the performance of continuous regeneration DPF apparatus and corresponding emission characteristics has been predicted well enough and verified with experimental results. The pressure and average temperatures are decreased to about 2.6% and 1.4% respectively under a full engine load condition mainly due to back pressures raised by diesel particulate filter. Pressure, temperature and heat releasing rates tend to decrease specially at higher engine load, but they are not affected at lower engine load regions.

• 한국항공우주학회지
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• 제35권3호
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• pp.253-259
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• 2007

다양하게 개발되고 있는 무인항공기 탑재 시스템의 신뢰도 확보를 위해 규격화된 설계와 적절한 환경시험 방법이 적용되어야 한다. 국내에서 개발되고 있는 무인항공기용 탑재 시스템은 다양한 기능을 구현할 수 있는 충분한 능력을 갖고 있다. 하지만, 대부분의 시스템은 상호 호환성이 없고, 환경에 대한 적응성도 보장되어 있지 않다. 본 논문에서는 유인항공기에 사용되는 ATR(Air Transport Rack) 규격을 설명하고 이를 바탕으로 무인항공기에 적용 가능한 탑재시스템의 ATR 규격을 제시하였다. 특히 COTS(Commercial off-the-shelf) 부품을 사용한 설계 방법을 제시하였다. 시스템이 전자/기계적 환경과 기상 환경에 적응 가능하도록 하기 위해 다양한 설계 방법을 적용하였다. 미국의 군사표준서(Military Standard)를 참고하여 실험실 단위에서 수행할 수 있는 시험 방법을 계획하고, 기준을 정하여 시험을 수행하였다.

• 한국광학회지
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• 제15권5호
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• pp.443-448
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• 2004

국제단위계 중의 하나인 칸델라 눈금을 두 개의 광도계를 사용하여 실현하였다. 광도계의 분광감응도는 광출력을 전기출력으로 치환하여 측정하는 극저온 절대복사계에 소급하여 측정하였다. 광도계 외부에 설치된 정밀 개구는 다이아몬드 회전가공기로 가공하였으며 그 면적은 불확도 0.05%(k = 1) 이내로 측정하였다. 이 광도계를 사용하여 광도 벤치 위에서 1 kW FEL 전구로 칸델라 단위를 실현할 때 불확도를 분광감응도, 감응도의 공간 균일도, 개구 면적, FEL 전구의 색온도와 위치 재현성을 고려하여 평가한 결과 0.25%(k = 1)를 얻었다. 실현한 눈금의 유효성을 확인하기 위하여 미국 NIST의 눈금과 비교한 결과 0.1% 이내에서 일치하였다.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.116-125
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• 2018

Modified 9Cr-1Mo ferritic steel is a preferred material for steam generators in nuclear power plants for their creep strength and good corrosion resistance. Austenitic stainless steels, such as type 316LN, are used in the high temperature segments such as reactor pressure vessels and primary piping systems. So, the dissimilar joints between these materials are inevitable. In this investigation, dissimilar joints were fabricated by the Shielded Metal Arc Welding (SMAW) process with Inconel 82/182 filler metals. The notch tensile properties and Charpy V-notch impact toughness properties of various regions of dissimilar metal weld joints (DMWJs) were evaluated as per the standards. The microhardness distribution across the DMWJs was recorded. Microstructural features of different regions were characterized by optical and scanning electron microscopy. Inhomogeneous notch tensile properties were observed across the DMWJs. Impact toughness values of various regions of the DMWJs were slightly higher than the prescribed value. Formation of a carbon-enriched hard zone at the interface between the ferritic steel and the buttering material enhanced the notch tensile properties of the heat-affected-zone (HAZ) of P91. The complex microstructure developed at the interfaces of the DMWJs was the reason for inhomogeneous mechanical properties.

• Corrosion Science and Technology
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• 제7권1호
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• pp.16-21
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• 2008

A non-phosphorous program employing an alkyl epoxy carboxylate (AEC) has been successfully applied to petrochemical and other large industrial open recirculating cooling water systems. AEC is a patented non-phosphorous calcium carbonate scale inhibitor that has demonstrated better scale inhibition abilities than traditional organic phosphonates. In addition to its antiscalant properties, AEC inhibits carbon steel corrosion when used at high dosages. AEC can be combined with zinc to form a non-phosphorous program with very low levels of phosphate to provide an environmentally acceptable program. In actual applications, the total phosphate developed in the cooling system from cycling the makeup is below 1 ppm as $PO_4$. This level has complied with the highest standards of wastewater discharge limitations. The performance of two AEC/Zinc applications is reviewed. In both cases excellent corrosion and scale control were achieved with AEC/Zinc programs. One case history details the performance with a low hardness water (100 ppm calcium, as $CaCO_3$) operating at 8-10 cycles of concentration. The corrosive nature of the water and the long retention time of the system stressed both the corrosion and scale control capabilities of the program. The second case history demonstrates the performance of the program with a moderate hardness water (400-600 ppm calcium, as $CaCO_3$), but under harsh conditions of high temperature and low flow. The AEC/zinc combination has been found to be highly effective in controlling the corrosion of ferrous metals. AEC can provide good corrosion inhibition at high concentrations, while zinc is known to be an excellent cathodic inhibitor. The combination of the two inhibitors not only provides a synergistic blend that is effective over a wide range of operating conditions, but also is environmentally friendly.

• 한국화재소방학회논문지
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• 제28권2호
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• pp.14-19
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• 2014

현재 국내의 침윤소화약제 기술기준은 표면장력에 대한 기준만 존재하여 이를 통한 약제의 성능평가는 어려운 실정이다. 따라서 침윤소화약제의 성능평가 기법을 제시하기 위해 축소모형 실험 장치를 통한 최적화된 성능평가 방법을 제시하고자 한다. 본 연구는 해외 기준인 NFPA 18의 실험과 자체 제작된 축소모형 실험 장치를 이용한 실험의 결과 비교분석을 통해 자체 제작 축소모형 실험 장치실험 결과의 타당성을 규명하고자 한다. 목화솜을 대상으로 침투성능만을 평가하는 NFPA 18 실험과 목분을 대상으로 침투성능과 소화성능을 모두 평가하는 축소모형 실험을 비교분석한 결과 NFPA 18의 실험과 자체 제작 축소모형 실험에서 모두 소화용수의 침투성에 관한 변별력을 확인할 수 있었다. 또한 자체 제작 축소모형 실험에서는 T/C를 통한 내부온도 측정을 통해 보다 명확한 변별력을 나타냄을 확인하였다.