• 공업화학
• /
• 제28권2호
• /
• pp.133-140
• /
• 2017

방사성 폐기물에 대한 우려가 증대됨에 따라 생물정화 기술에 대한 관심이 고조되고 있다. 병원과 원자력발전 등에서 발생되는 많은 양의 방사성 폐기물이 환경에 직접 노출됨에 따라, 이를 정화하기 위한 다양한 물리화학적 기술이 보고되고 있다. 하지만, 이러한 방법은 고비용 및 고위험성 과정이 수반되기 때문에 미생물을 이용한 친환경적 생물정화 기술이 요구되고 있다. 최근, 고방사선 노출 등과 같은 극한환경에서 서식할 수 있는 방사선저항성 미생물에 대한 연구가 많이 보고되고 있으며, 이를 이용한 방사성 폐기물 정화에 대한 연구적 관심이 높아지고 있다. 데이노코쿠스 라디오두란스는 대표적인 방사선저항성 미생물로써 높은 방사선에 저항성을 갖는 특성으로 인해 방사성 폐기물 등의 유해물질 정화에 이용될 수 있다. 본 총설에서는 데이노코쿠스 라디오두란스의 방사선내성과 관련한 일반적 기작에 대해 소개하고, 방사성 폐기물의 생물정화 활용 가능성에 대해 논의한다.

• 터널과지하공간
• /
• 제21권3호
• /
• pp.225-234
• /
• 2011

본 연구에서는 암반에서의 열 전달과 관련된 열-역학적 거동을 평가하기 위한 현장 히터시험을 국내 최초로 실시하였다. 현장시험을 위해 현장조건과 시험 목적에 부합하는 시추공 히터시험을 설계하고 히터장치, 관측용 센서, 데이터로깅 시스템의 설치가 이루어졌다. 시험 구간에서의 노출면 조사를 통해 고경사 절리가 우세하게 분포함을 알 수 있었으며 암석코아에 대한 실험실 실험을 통해 히터시험구간에서의 주요 열, 역학적 암반 물성을 결정하였다. 암반의 온도분포 변화를 통해 암반 내에 존재하는 절리의 영향과 터널 벽면으로의 열손실을 파악할 수 있었으며 히터온도가 $90^{\circ}C$로 유지되는 경우, 히터공에서 0.3 m 떨어진 암반의 온도는 최대 $40^{\circ}C$까지 상승함을 알 수 있었다.

• Journal of Biosystems Engineering
• /
• 제19권4호
• /
• pp.358-368
• /
• 1994

Major factors in reducing the stacking strength of corrugated fiberboard boxes in cold storage or transport conditions are high relative humidity, causing elevated moisture absorption by the boxes. The bottom boxes in a stack will deform to the critical deflection causing agricultural products damage there, and eventually additional deflection will cause box collapse and finally toppling of the stack. The study was conducted to determine the water absorption characteristics and the compressive strength of the corrugated fiberboard boxes being widely used in packaging agricultural products in Korea. The sample boxes for the study were selected from the regular slotted containers (RSC) types, and one was the box used in apple packaging (Box A), another one was the box used in pear packaging (Box B). The corrugated shipping containers were made from a large portion of recycled fibers in Korea, and comparing with Box B, Box A was fabricated from fiberboard which contained more percentage of old corrugated containers (OCC) imported from foreign countries than domestic waste paper. The results obtained from the study were summarized as follows ; 1. Equilibrium moisture content (EMC) of the sample boxes was established after about 20 hours, and the EMC by absorption was lower than that by desorption. The EMC increased with the increasing of relative humidity and with the decreasing of temperature, and the rate of increasing was much higher above the relative humidity of 50%. 2. The maximum compressive strength of Box A was about 100 kgf greater than that of Box B on the same enviromental conditions. The strength of the sample boxes decreased rapidly with the increasing of relative humidity. The effect of relative humidity on the strength was a little higher than that of temperature. 3. As the applied load was progressively increased and a level was reached, the vertical side panels ($L{\times}D$) deflected laterally inwards or outwards. The panels deflected laterally inwards at higher relative humidity. 4. The maximum compressive deflection ratio and the critical deflection ratio of the sample boxes were increased linearly with the increasing of relative hunidity, but trends for its ratios showed inconsistant response to temperature.

• 화약ㆍ발파
• /
• 제27권1호
• /
• pp.21-31
• /
• 2009

터널의 굴착이나 응력 재분포에 의해 터널 주변에는 암반 손상대(EDZ) 구간이 발생하게 되며, 이는 암반의 역학적 수리적 물성변화를 초래하여 추가적인 균열발생 및 지하수의 주요 공급로 역할을 하게 된다. 본 연구에서는 방사성폐기물 처분연구시설(KURT)을 대상으로 현장실험을 통해 암반변형계수를 측정하였고, 이를 바탕으로 손상대 영역을 세분화하여 FLAC2D를 이용한 전산해석을 실시하였다. 실험결과 KURT 주변에는 측정지점에 따라 0.6~1.8m의 손상영역이 발생하였으며, 손상대 구간의 변형계수 값은 주변 암반 변형계수의 약 40%에 해당하였다. 암반손상대로 인해 KURT 내 터널변위는 약 65%의 추가변위가 발생하였고, 최대 주응력은 58% 감소되었음을 확인하였다. 또한 손상대 영역의 고려로 인해 터널의 좌 우측 하단부에 발생되었던 소성 영역이 터널의 천정 및 바닥부근으로 확대되는 경향을 보였다.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• 제17권3호
• /
• pp.178-185
• /
• 2014

Purpose: The use of dietary supplements (DS) has increased in most nations. We investigated the amount of DS intake in the Korean population by analyzing a national survey, to support the preparation of a national institutional strategy regarding DS intake and marketing. Methods: The data of the fifth Korea National Health and Nutrition Examination Survey (a year between 2010 and 2012) were investigated, analyzing the rate of DS intake, and the characteristics of the intake group and non-intake group in Korean preschool children. Results: The intake rate of DS was 49.0-54.2% (1,313,874-1,491,240) and 19.6-30.3% (250,603-421,922) in children from 1 to 6 years old and in those less than 1 year, respectively, from 2010 to 2012. The highest intake rate was observed in the age group of five. The mean age was significantly higher in the DS intake group than in the non-intake group. Intake of essential nutrients, minerals, and vitamins were also higher in the DS intake group. The level of family income was significantly associated with the intake rate (p<0.001). In children less than 1 year, probiotics accounted for the highest intake of DS. Conclusion: Korean preschool children have high consumption of DS. Therefore, problems may arise from the waste of money purchasing unnecessary DS, and from the overuse of DS in preschoolers who do not require DS intake. We hope these results can be used to produce an appropriate national institutional strategy regarding DS intake and marketing.

• 터널과지하공간
• /
• 제18권3호
• /
• pp.219-225
• /
• 2008

고준위폐기물처분장의 설계 및 장기 성능평가를 위한 입력자료를 확보하기 위해, 한국원자력연구원 지하처분연구시설 부지에서 실시된 경사시추에서 얻은 암석 코어를 이용하여 화강암의 열전도도를 측정하였다. 측정을 위한 시료는 다양한 지표면으로부터의 심도에서 채취되었으며, 건조 조건과 물로 포화된 조건에서 열전도도가 측정되었다. 건조 조건에서 화강암의 열전도도는 공극률이 증가함에 따라 감소하였으며, 2.1 W/mK에서 3.1 W/mK 사이의 범위에 있었다. 동일 암석 코어에서 얻은 화강암 시료에 대해 포화 조건에서 측정된 화강암의 열전도도는 건조 조건에서 특정된 값보다 큰 값을 나타내어 2.9 W/mK에서 3.6 W/mK 사이의 범위에 있었다. 조사부지 내 화강암의 열전도도에 대한 이방성의 영향은 작은 것으로 나타났다.

• 환경위생공학
• /
• 제24권2호
• /
• pp.17-30
• /
• 2009

In Iksan city, there have been a lot of complaints caused by offensive odor from residents living near the public environmental infrastructures and the Iksan industrial complex. To solve these problems, it is important to know the present condition of odor pollution level in these areas, the emission characteristics of malodorous gases in temporal and spatial variations in addition to meteorological components, and the facilities of major sources emitting malodorous compounds. The objectives of this study is to make the odor monitoring network for 20 people who lived and worked in areas where the environmental infrastructures and the Iksan industrial complex are located and their neighboring areas for six months from June 1st to October 31st in 2008 in Iksan and to monitor the temporal and regional frequency and characteristics of odor intensity using direct olfactory methods. As a result of odor monitoring, the highest frequency of sensed odor per month and 20 people for six months was found to be 107 in July, followed by 84 in September, 80 in August, 54 in June, 38 in October, respectively. Odor intensity trend showed a regional trend in the decreasing order of Dongsan-dong, Busong-dong, and Palbong-dong. Odor was widely perceived from night through next morning and considered as the sense of excreta, chemicals, sewage, compost, waste, etc. When high odor intensity was sensed, there were constant meteorological characteristics: relative humidity was 80~90%, wind speed was less than 0.5~1 m/sec, and main wind directions were from the east, the southeast, and the south.

• 디지털산업정보학회논문지
• /
• 제14권3호
• /
• pp.45-53
• /
• 2018

The Personal Information Protection Act has been revised continuously since its establishment, and as a way to secure stability properly, the guidelines as well as enforcement ordinances and regulations have been changed, too. It seems that people's recognition and awareness of private information have already evolved to a certain level that is regarded to be fairly high. However, no one can exactly imagine how much ripple effect scrapping discarded paper regarded simply as waste material which is often and easily practiced in our everyday lives exerts and how many socially significant events it may arouse in our lives. Private information is produced, operated, preserved, utilized, distributed within the frame of law unidentified, and then discarded with a particular purpose. While going through a series of processes, each piece of that private information comes to be reproduced melting a lot of information. It is used and also changed beneficially sometimes to richen our lives or as basic material for welfare. Meanwhile, its importance is decided by its weight or mass and then often gets discarded after all. It means that the process of disuse is being done in a way to arouse the possibility of invasion of personal rights and also the second and third and also more exposure of private information. Therefore, approaching the meaning of automation politically, this study aims to suggest how to secure stability in the process of discarding private information in terms of logical automation.

• 한국전자거래학회지
• /
• 제17권2호
• /
• pp.149-163
• /
• 2012

물류 시스템은 다양한 프로세스에 걸친 한정된 자원들의 작업을 통해 고객에게 서비스를 제공한다. 이와 같은 복잡한 환경에서 높은 서비스 수준을 유지하기 위해서는 프로세스 진행 상황에 대한 실시간 모니터링과 그를 통한 성과 달성도의 지속적인 관리가 필수적으로 요구된다. 본 연구에서는 컨테이너 터미널을 대상으로 선박 물류 프로세스의 서비스 완료시간을 예측하는 방법론을 제시한다. 이를 위해 먼저 선박에서 컨테이너를 싣고 내리는 프로세스에 영향을 미치는 요인을 파악한다. 그리고, 확인된 요인들 중 영향 정도를 직접적으로 측정하기 어려운 것에 대해 정량적인 값을 추정하는 방안을 개발한다. 서비스 완료 시간에 대한 실시간 예측은 의사결정 나무를 사용한다. 과거 프로세스 진행 이력을 바탕으로 의사결정 나무를 학습시킨 후, 특정 시점에서 실시간 요인의 상태를 이용하여 서비스 완료시간을 예측한다. 컨테이너 터미널 시뮬레이션 모형을 활용하여 본 연구에서 제시하는 방법론을 검증하였다.

• Nuclear Engineering and Technology
• /
• 제40권7호
• /
• pp.593-606
• /
• 2008

In this study, data on radionuclide migration and retardation processes in the engineered and natural barriers of High-Level Radioactive Waste (HLW) repository have been reviewed and compiled for use in the performance assessment of a HLW disposal system in Korea. The status of the database on radionuclide migration and retardation that is being developed in Korea is investigated and summarized in this study. The solubilities of major actinides such as D, Th, Am, Np, and Pu both in Korean bentonite porewater and in deep Korean groundwater are calculated by using the geochemical code PHREEQC (Ver. 2.0) based on the KAERI-TDB(Korea Atomic Energy Research Institute-Thermochemical Database), which is under development. Databases for the diffusion coefficients ($D^b_e$ values) and distribution coefficients ($K^b_d$ values) of some radionuclides in the compacted Korean Ca-bentonite are developed based upon domestic experimental results. Databases for the rock matrix diffusion coefficients ($D^r_e$ values) and distribution coefficients ($K^r_d$ values) of some radionuclides for Korean granite rock and deep groundwater are also developed based upon domestic experimental results. Finally, data related to colloids such as the characteristics of natural groundwater colloids and the pseudo-colloid formation constants ($K_{pc}$ values) are provided for the consideration of colloid effects in the performance assessment.