• 대한환경공학회지
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• 제35권9호
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• pp.666-674
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• 2013

담수생태계에서 갈수기가 지속되면 다양한 물리적 장애가 발생한다. 이 시기는 어류의 생태 유지용수가 부족하여, 이동이 일어남에 따라 새로운 피난처 및 서식처가 요구된다. 이러한 문제를 해결하기 위해 본 연구에서는 실증규모의 실험시설을 구축하였으며, 수위변화와 어류 피난처의 관계를 분석하였다. ADP (artificial deep pool)는 본 연구에서 제안된 인공적인 깊은 웅덩이이다. 본 시설을 실증규모의 test-bed 실험구에 적용하여 모니터링 한 결과, 수위변화에 따른 어류 개체수는 실험연못의 수심 0.5 m에서 가장 높게 나타났다. 하지만 ADP에서는 낮은 외부 수위 조건(<0.3 m)에서 단위면적당 어류 개체수가 증가하였고, 실험구의 총 어류 군집을 보존하는데 기여하였다. 또한, ADP 내부의 수온과 DO는 외부보다 낮게 조성되었지만, 어류는 지속적으로 서식하였다. 이 결과와 관련하여, ADP 내부는 WCS, OS, SS, TS 등이 높은 효율적인 정수생태계임을 나타내었다. 더욱이, ADP 내부의 종풍부도는 Acheilognathus koreensis (A. koreensis), Carassius carassius (C. carassius)와 같은 WCS가 높은 비율로 측정되었다. 결국, 수위가 낮게 형성되는 동안 어류는 서식환경의 교란에 의해 수심이 깊은 곳으로 피난하였고, 본 연구 결과를 종합하여 볼 때, ADP는 정수생태계에 적합한 어류 피난 및 서식처로 활용이 가능함을 시사하였다.

• Journal of Biosystems Engineering
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• 제1권1호
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• pp.55-55
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• 1976

An experimental work was conducted to develop an optimum operating system of various hay drying systems ; sun-drying with long hay, sun-drying after chopping, sun-drying after crushing, heated air drying after chopping using batch-type dryer and heated air drying after crushing using tunnel-type dryer. Seombody having 60 cm long and initial moisture content of approximately 79 % in wet basis was used for the experiment. The criteria selected for determining the optimum operating condition were the drying performance rate, the production cost and quality of dried matter of each drying systems. The result of this study are summarized as follows : 1. Drying characteristics of leaves of long stem hay, chopped seombody and crushed one were obtained by maintaining the oven temperature at 70 degrees centigrade. The required drying times for various samples to approximately 15% moisture content in wet basis were about 50 min .for leaves ; 160 min. for crushed hay ; 250 min. for chopped hay ; 340min. for ling hay and more than 360 min .for stems. The drying time of crushed hay was required about 50 % of that for the uncrushed long hay. Such a significant difference of drying of time between the leaf and long stem may indicate that an effective drying of seombody may not be achieved unless any kind of special process treatment for the whole hay is undertaken. 2. In each individual drying system, the following conclusions were drawn: a. After 8 days sun-drying on concrete floor under good days with average tempe?rature at $256{\circ}C$ and relative humidity at 55% at 2 P.M., the moisture content of long hay was still above 25 5'~ and the leaf loss during drying caused by wind and rough handling was more than 50 ~G. b. It was possible to dry the chopped seombody by sun-drying down to about 10 % moisture content within 5 days, however, a stock of heat and discolouration phenomena were observed during the drying, which may be due to the increased deposit-density by chopping, resulting in lowering the quality of the dried product. c. Sun-drying for the crushed material by hay-conditioner was required about 4 days to reduce the moisture content to about 10 %, keeping the quality of dried product at good grade. o. The optimum deposit-depth of the chopped seombody in the batch-type dryer used was about 28cm with about 42kg/hr of drying performance rate. However, it was necessary to overturn the materials between the upper and lower layers in order to obtain a good quality of dried product. d. The drying performance rate by the tunnel-type drier was highest among those of drying systems tested, giving the rate of approximately 400kg/day. 3. On reviewing the individual drying system for seombody, it was possible to draw conclusion that the best system was tunnel drying with the crushed seombody as far as the performance rate was concerned. However, the methods gives the highest operational cost. The system for the lowest operational cost with good quality of dried product was the sun-drying with the crushed material. Accordingly, it may be recommended that the system of sun-drying for the crushed seombody may be the most feasible system presently applicable to farm-level operation.

• Journal of Biosystems Engineering
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• 제1권1호
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• pp.56-63
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• 1976

An experimental work was conducted to develop an optimum operating system of various hay drying systems ; sun-drying with long hay, sun-drying after chopping, sun-drying after crushing, heated air drying after chopping using batch-type dryer and heated air drying after crushing using tunnel-type dryer. Seombody having 60 cm long and initial moisture content of approximately 79 % in wet basis was used for the experiment. The criteria selected for determining the optimum operating condition were the drying performance rate, the production cost and quality of dried matter of each drying systems. The result of this study are summarized as follows : 1. Drying characteristics of leaves of long stem hay, chopped seombody and crushed one were obtained by maintaining the oven temperature at 70 degrees centigrade. The required drying times for various samples to approximately 15% moisture content in wet basis were about 50 min .for leaves ; 160 min. for crushed hay ; 250 min. for chopped hay ; 340min. for ling hay and more than 360 min .for stems. The drying time of crushed hay was required about 50 % of that for the uncrushed long hay. Such a significant difference of drying of time between the leaf and long stem may indicate that an effective drying of seombody may not be achieved unless any kind of special process treatment for the whole hay is undertaken. 2. In each individual drying system, the following conclusions were drawn: a. After 8 days sun-drying on concrete floor under good days with average tempe\ulcornerrature at $256{\circ}C$ and relative humidity at 55% at 2 P.M., the moisture content of long hay was still above 25 5'~ and the leaf loss during drying caused by wind and rough handling was more than 50 ~G. b. It was possible to dry the chopped seombody by sun-drying down to about 10 % moisture content within 5 days, however, a stock of heat and discolouration phenomena were observed during the drying, which may be due to the increased deposit-density by chopping, resulting in lowering the quality of the dried product. c. Sun-drying for the crushed material by hay-conditioner was required about 4 days to reduce the moisture content to about 10 %, keeping the quality of dried product at good grade. o. The optimum deposit-depth of the chopped seombody in the batch-type dryer used was about 28cm with about 42kg/hr of drying performance rate. However, it was necessary to overturn the materials between the upper and lower layers in order to obtain a good quality of dried product. d. The drying performance rate by the tunnel-type drier was highest among those of drying systems tested, giving the rate of approximately 400kg/day. 3. On reviewing the individual drying system for seombody, it was possible to draw conclusion that the best system was tunnel drying with the crushed seombody as far as the performance rate was concerned. However, the methods gives the highest operational cost. The system for the lowest operational cost with good quality of dried product was the sun-drying with the crushed material. Accordingly, it may be recommended that the system of sun-drying for the crushed seombody may be the most feasible system presently applicable to farm-level operation.

• 한국구조물진단유지관리공학회 논문집
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• 제22권4호
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• pp.10-18
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• 2018

본 연구는 시멘트 모르타르속에 매입된 철근주위가 건조될 때 불안정한 전류분포의 영향을 측정하고, 교류 임피던스 특성변화에 대한 영향을 고찰하는 것을 목적으로 한다. 건조과정중 철근의 전기화학적 반응을 측정하기 위해, 두 개의 철근이 매입된 3개의 시멘트 모르타르가 실험을 위해 준비되었다. 주요 변수는 20mm 모르타르 두께를 동일하게 가지도록 하여, 두 철근사이의 간격이 10, 20과 30mm가 되도록 하였다. 해양환경에서 콘크리트 구조물속의 철근 부식속도를 가정하기 위해서, 3개의 모르타르 시험체는 15 사이클의 침지-건조환경(해수에서 24시간 침지와 48시간 실온 건조)에 노출되었다. 부식전위의 변화는 건조중에 용존산소의 확산속도 증가로 인해 귀한 방향으로 이동하는 것이 관찰되었다. 침지-건조환경에서 교류 임피던스는 100kHz에서 1mHz까지 측정되었다. 철근과 모르타르사이의 계면상태를 설명하기 위해 이론적 모델이 제안되었으며, 그것은 용액저항, 전하이동저항과 CPE로 구성된 등가회로를 사용하였다. 철근의 부식이 진행됨에 따라, 저주파수 영역에서 확산 임피던스가 나타났다. 침지-건조 환경중 건조과정에서 이송차가 $45^{\circ}$에 가까워지는 현상으로써 전류분포가 불균일해지는 경향을 보였다.

• Nuclear Engineering and Technology
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• 제46권4호
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• pp.547-556
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• 2014

Korea expects a shortage in storage capacity for spent fuels at reactor sites. Therefore, a need for more metal and/or concrete casks for storage systems is anticipated for either the reactor site or away from the reactor for interim storage. For the purpose of interim storage and transportation, a dual purpose metal cask that can load 21 spent fuel assemblies is being developed by Korea Radioactive Waste Management Corporation (KRMC) in Korea. At first the gamma and neutron flux for the design basis fuel were determined assuming in-core environment (the temperature, pressure, etc. of the moderator, boron, cladding, $UO_2$ pellets) in which the design basis fuel is loaded, as input data. The evaluation simulated burnup up to 45,000 MWD/MTU and decay during ten years of cooling using the SAS2H/OGIGEN-S module of the SCALE5.1 system. The results from the source term evaluation were used as input data for the final shielding evaluation utilizing the MCNP Code, which yielded the effective dose rate. The design of the cask is based on the safety requirements for normal storage conditions under 10 CFR Part 72. A radiation shielding analysis of the metal storage cask optimized for loading 21 design basis fuels was performed for two cases; one for a single cask and the other for a $2{\times}10$ cask array. For the single cask, dose rates at the external surface of the metal cask, 1m and 2m away from the cask surface, were evaluated. For the $2{\times}10$ cask array, dose rates at the center point of the array and at the center of the casks' height were evaluated. The results of the shielding analysis for the single cask show that dose rates were considerably higher at the lower side (from the bottom of the cask to the bottom of the neutron shielding) of the cask, at over 2mSv/hr at the external surface of the cask. However, this is not considered to be a significant issue since additional shielding will be installed at the storage facility. The shielding analysis results for the $2{\times}10$ cask array showed exponential decrease with distance off the sources. The controlled area boundary was calculated to be approximately 280m from the array, with a dose rate of 25mrem/yr. Actual dose rates within the controlled area boundary will be lower than 25mrem/yr, due to the decay of radioactivity of spent fuel in storage.

• 한국식품저장유통학회지
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• 제10권4호
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• pp.441-446
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• 2003

시설채소산물을 습도조절이 가능한 원적외선 방사체 저장고(5$^{\circ}C$ 또는 1$0^{\circ}C$의 온도와 90%의 상대습도)에 저장한 결과 채소류의 선도유지기간이 연장되는 것을 확인하였고, 중량손실율은 원적외선 방사체 저장고에 저장한 채소류가 중량손실율이 대조구에 비하여 낮게 나타났다. 따라서 습도조절이 가능한 원적외선 방사체 저장고에 채소류를 저장함으로서 채소류의 수분손실을 방지할 수 있음을 확인할 수 있었으며, 일정기간동안 원적외선 방사체 저장고에 저장함으로써 ascorbic acid함량의 감소를 대조구에 비하여 낮은 비율로 억제할 수 있었다. 총균수의 경우 채소류 시험구에서 원적외선 방사체 저장고에서 저장할수록 오염미생물의 총균수가 낮게 나타났다. 표면색도의 경우, a값은 모든 시험구에서 감소하였으며 원적외선 방사체 시험구에 비하여 대조구 저장시료의 표면색도가 청색도를 증가시키는 변화를 관찰할 수있었고, b값은 시료간에 유의성 있는 차이없이 다소 증가하는 것으로 나타났다. 부패율은 수분 함유율이 높은 채소류 일수록 원적외선 방사체 저장시설을 이용하는 경우, 부패율을 낮게 유지할 수 있었다. pH의 변화는 채소류를 저장하는 기간이 증가할수록 pH는 더 낮아졌고, 대조구에 비해 원적외선 방사체 저장고의 시험구의 pH는 변화율은 적었다. 따라서, 원적외선 방사에 저장시설내에 오이, 호박 및 방울토마토와 같은 채소류를 저온고습도상에서 저장할 경우, 채소류의 품질변화를 최소화 할 수 있어 갓 수확한 채소류의 선도유지기간을 연장할 수 있는 저장법이 될 수 있음을 확인하였다.

• 한국건설관리학회논문집
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• 제7권4호
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• pp.137-145
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• 2006

건설공사에 있어서 작업불가능일수 산정은 정확한 공사기간을 예측하는데 있어 매우 중요한 요소이다. 하지만 기후요소는 예측의 불확실성을 지니고 있어 정확한 공기산정을 어렵게 한다. 또한 기존의 작업불가능일수 산정에 관한 연구는 대부분 철근콘크리트공사를 대상으로 하고 있어, 철근콘크리트의 작업불가능 기준을 철골공사에 적용할 경우에는 많은 오차가 생기게 된다. 본 연구에서는 문헌조사 및 현장 조사 등을 통해 기후요소를 고려한 철골공사의 작업불가능 기준을 설정하고, 이를 서울지역의 15년간 기상데이터에 적용시켜 1년간의 철골공사 총 작업불가능일수를 산정하였다. 철공공사에 영향을 미치는 기후요인으로는 기온, 바람, 강설, 강우 등이 선정되었으며, 철공공사 여러 공종 중 옥외에서 수행되며 철공공사 공기에 많은 비중을 차지하는 철골 설치작업을 대상으로 각 기후요소들이 미치는 영향을 분석하였다. 본 연구에서의 분석결과, 서울지역에서 기후요소로 인해 철골설치 작업불가능일이 연간 총 58일로 산정되었으며, 각 월별 작업불가능일수가 제시되었다. 본 연구의 결과는 다른 지역의 기상데이터를 적용할 경우 타 지역에서의 철골공사 작업불가능일 산정에도 활용될 수 있을 것이며, 이러한 작업불가능일의 산정은 철골공사의 보다 정확한 공기산정과 최적의 착공시기 결정에 도움이 될 것이다.

• 한국세라믹학회지
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• 제20권2호
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• pp.135-146
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• 1983

This study is to investigate the properties of domestic fly ash for utilization as data in regard to fly ash which is by-product of domestic coal powder plants and the possibility of utilization as insulation material of domestic fly ash. Composition refractoriness size distribution density contents of hollow particles and crystalline phase were examined as the properties of domestic fly ash. As to the fired test pieces of fly ash by itself that varied contents of hollow particles with four kinds and of the fly ash-clay-saw dust system linear shrinkage bulk density app. porosity compressive strength thermal conductivity and structures were investigated for the possibility of utilization as an insulation material. The results are as follows : 1. The properties of the fly ash I) The constituent particle of the fly ash is spherical and it contains not a few hollow particles (floats by water 0.30-0.50 floats by $ZnCl_2$ aq.(SpG=1.71) 6.97-16.72%). ii) The chemical compositions of fly ash are $SiO_243.9-54.1%$ , $Al_2O_321.0-30.7%$ Ig loss is 7.4-24.1% and the principal of Ig loss is unburned carbon. iii) Fly ash was not suitable to use for mortar and concrete mixture because Ig. loss value is higher than 5% 2. Utilization as insulation material I) The test pieces of original fly ash floats by water floats by ZnCl2 aq(SpG=1.71) p, p t by ZnCl2 aq.(SpG=1.71) that were fired at 110$0^{\circ}C$ represented 0.11-0.18 kcal/mh$^{\circ}$ C as thermal conductivity value. ii) The test pieces which (76.5-85.5) wt% fly ash-(8.5, 9.5) wt% clay-(5.0-15.0) wt% saw dust system(68.0-72.0) wt% fly ash -(17.0-18.0)wt% clay-(10.0-15.0) wt% saw dust system and 59.5 wt% fly ash-25.5 wt% clay-15.0wt% saw dust system were fired at 110$0^{\circ}C$ the thermal conductivity was less than 0.1Kcal/mh$^{\circ}$ C. iii) In view of thermal conductivity and economic aspect insulation materials which added saw dust as blowing agent and clay as inorganic binder are better than that of fly ash as it is or separated hollow fly ash particles. iv) When the saw dust contents increased in the (59.5-90.0) wt% saw dust system and when amount of clay de-creased and firing temperature decreased under the condition of equal addition of saw dust app. porosity increased but bulk density compressive strength and thermal conductivity decreased.

• 대한약침학회지
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• 제18권1호
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• pp.63-71
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• 2015

Objectives: This study was carried out to analyze the single-dose toxicity of Eun-Bi San pharmacopuncture injected into the muscle of Sprague-Dawley (SD) rats. Methods: All experiments were performed at Biotoxtech, an institution certified to conduct non-clinical studies under the Good Laboratory Practice (GLP) regulations. Six week old SD rats reared by ORIENTBIO were chosen for this pilot study. The reason SD rats were chosen is that they have been widely used in safety tests in the field of medicine, so the results can be easily compared with many other databases. The Eun-Bi San pharmacopuncture was made in a clean room at the Korean Pharmacopuncture Institute (KPI, K-GMP). The constituents of the Eun-Bi San pharmacopuncture are Angelicae gigantis radix, Strychni semen and Glycyrrhizae radix. These were extracted at low temperature and low pressure in an aseptic room at the KPI. Doses of Eun-Bi San pharmacopuncture, 0.25, 0.5 and 1.0 mL, were administered to the experimental groups, and a dose of normal saline solution, 1.0 mL, was administered to the control group. This study was performed under the approval of the Institutional Animal Ethics Committee of Biotoxtech Co., Ltd. Results: No deaths or abnormalities occurred in any of the four groups. No significant changes in weight, hematological parameters or clinical chemistry between the control group and the experimental groups were observed. To determine if abnormalities existed in any organs and tissues, we used microscopy to examine representative histological sections of each specified organ; the results showed no significant differences in any of the organs or tissues. Conclusion: The results of this study suggest that treatment with Eun-Bi San pharmacopuncture is relatively safe and that its clinical use may be beneficial. Further evaluations and studies on this subject will be needed to provide more concrete evidence in support of these conclusions.

• 대한환경공학회지
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• 제34권9호
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• pp.623-629
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• 2012

본 연구는 집수면으로 사용되는 지붕재질에 따라 집수되는 빗물의 수질을 평가하고, 지붕면에서 지의류/이끼의 존재여부에 따른 수질변화를 관찰하였다. 실험은 5가지 다른 재질의 재료[나무, 나무(이끼 서식), 콘크리트, 초벌기와, 슬레이트]로 설치된 지붕면에서 수행되었다. 각 지붕면에서의 빗물수질을 관찰한 결과, 초벌기와 지붕으로부터 집수된 빗물이 이용에 가장 적합한 재료로 나타났다. 이는 초벌기와 재질 특성에 따른 표면 온도의 상승과 자외선에 의한 살균효과 때문인 것으로 판단된다. 이끼류가 포함된 나무지붕과 일반 나무 지붕에서 집수된 빗물의 수질을 비교한 결과 이끼는 TOC, nitrate, sulfate 및 phosphate 농도에 영향을 미치는 것으로 관측되었다. 그리고 슬레이트 지붕으로부터 유출된 빗물 내 석면의 농도는 평균 0.002개/$cm^3$로 검출되었으며 이러한 결과는 환경부 다중이용시설기준 및 노동부 사무실 기준인 0.01개/$cm^3$ 규정을 만족한 것으로 나타났다.