물 유거(Run-off)에 따른 토양유실량을 자동정량하고자 ISCO 6712 수질환경 종합측정장치를 이용하여 토양유실량 추정장치를 고안하였고, 이 장치를 통해 실시간으로 유실되는 토양량을 추정할 수 있었다. 토양유실량 추정장치는 ISCO 6712 장치에 수위계(ISCO 730), 우량계(ISCO 674) 그리고 흙탕물을 받는 저수조 내에 층위 별로 흙탕물을 자동으로 채취할 수 있는 시설을 추가하였다. 1 × 5 m2 크기, 경사 15 %의 라이시미터(lysimeter) 내 석비레(Saprolite) 토양에 옥수수를 심어 실험한 결과 2017년 1회 강우량 161.3 ㎜의 강우사상에서는 실측 토양유실량의 85.1%, 82.6 ㎜ 강우사상에서는 101.7 %의 토양량을 추정하였다.

PURPOSES : It is well known that low temperature cracking is one of the most serious distresses on asphalt pavement, especially for northern U.S. (including Alaska), Canada and the northern part of south Korea. The risk of thermal cracking can be numerically measured by estimating thermal stress of a given asphalt mixture. This thermal stress can be computed by low temperature creep testing. Currently, in-direct tensile (IDT) mixture creep test mentioned in AASHTO specification is used for measuring low temperature creep properties of a given asphalt mixture. However, IDT requires the use of expensive testing equipment for performing the sophisticated analysis process, however, very few laboratories utilize this equipment. In this paper, a new and simple performance test (SPT) method: bending beam rheometer (BBR) mixture creep testing equipment is introduced, and the estimated experimental results were compared with those of conventional IDT tests. METHODS: Three different asphalt mixtures containing reclaimed asphalt pavement (RAP) and roofing shingles were prepared in the Korea Expressway Corporation (KEC) research laboratory. Using the BBR and IDT, the low temperature creep stiffness data were measured and subsequently computed. Using a simple power-law function, the creep stiffness data were converted into relaxation modulus, and subsequently compared. Finally, thermal stress results were computed from relaxation modulus master curve using Gaussian quadrature approach with condierations of 24 Gauss number. RESULTS: In the case of the conventional asphalt mixture, similar trends were observed when the relaxation modulus and thermal stress results were compared. In the case of RAP and Shingle added mixtures, relatively different computation results were obtained. It can be estimated that different experimental surroundings and specimen sizes affected the results. CONCLUSIONS: It can be said that the BBR mixture creep test can be a more viable approach for measuring low temperature properties of asphalt mixture compared to expensive and complex IDT testing methods. However, more extensive research and analysis are required to further verify the feasibility of the BBR mixture creep test.

Abstract1It takes lots of time and labor if a worker have to measure the water quality at a certain but designated time every day in an un-automated aqua farm. In addition, if the equipment is soaked in the sea water consistently, it will be contaminated by diverse floating matters and barnacles, and it often becomes mal-functional within 2~3 months. Therefore, we need to develop a system with which the sensed data could be checked in real time and operated automatically, while preventing the contamination of the sensor, a crucial component for water quality measuring equipment, as much as possible, and increasing the replacement cycle. We have developed a non-cleaning water quality measuring equipment and its software which are used in the fishery household of offshore aqua farms. By providing the workers with a mobile application which has a function of monitoring the water quality in real time, they can check the situation directly without going to the fishery household.

PURPOSES : The purpose of this study is development of automatic equipment to measure the road water-reservoir which can be one of factors for road traffic safety inspection and its application to safety analysis. METHODS : The scopes of this study are the examination of the riskiness and location of road water-reservoir through literature review, development of appropriate sensor and automatic equipment to survey the road water-reservoir and evaluation of field application. RESULTS: The laser lighting and IR camera were selected to develop the equipment. It was found from the field calibration that there is a high correlation between rutting and road water-reservoir and road water-reservoir caused by rutting can be correctly calculated. About 20.2km of national highway were inspected for case study and field application. It was found from correlation of traffic incident that 2.08km of the latent length for water-reservoir which is related to 12 traffic incidents were analyzed. CONCLUSIONS : This technique can be utilized evaluation method for road condition such as road water-reservoir for conventional evaluation system such as road traffic safety assessment and safety analysis and it can be use to new evaluation system to apply various road condition and traffic condition.

본 논문에서는 OSL 도트 선량계의 교정인자, 흡수선량 선형성, 피크전압 선형성, 각도 변화에 의한 흡수선량 변화를 측정하고 분석했다. 의료용 X 선발생 장치를 사용하여 조사에 노출 선량 보정 계수, 흡수선량 선형성, 피크 전압 선형성은 모두 IEC-62387-1 (2007) 기준을 만족하였다. 기준 방사선 노출과 관련하여 0도, 30도 및 60도에서 선량계 방향에 대한 기준은 -29 % (± 30 °) 및 + 67 % (± 60 °)이었다. 30도에서 측정 된 값은 기준보다 -8 % 낮고 60도에서 기준보다 -18 % 낮게 나타났다. 그러므로 OSL 도트 선량계 사용 시 방향에 따른 영향을 보정하여야 한다.