Diverse studies are being conducted on sewage sludge treatment and recycling methods, but the demand for a lowcost treatment technology is high because the sewage sludge has an 80% or higher water content and a high energy consumption cost. For this purpose, the waste volume can be reduced and solid fuel can be obtained from the Thermal Hydrolysis Reaction (THR) that consumes a small amount of energy. The experiment was conducted at a reaction temperature of 170-220oC and maintain for 1 hour at the final temperature. According to the Capillary Suction Time (CST) and Time to Filter (TTF) evaluation, the dewater ability was good after the temperature reached 200oC and did not significantly differ at the 200oC and higher reaction temperatures. The heating value of the dehydrated solid product was 3,800-4,200 kcal/kg, and its yield rate decreased from approximately 80% to 60% with the increase in the reaction temperature. To evaluate the efficiency of anaerobic digestion, the water quality of the liquid product was analyzed based on the reaction temperature. At the temperatures of 200oC and higher, the concentration of ammonia, which increases the pH and hinders anaerobic digestion rapidly increased. From the overall evaluation of the dehydrating efficiency, solid fuel quality, and anaerobic digestion efficiency during the thermal hydrolysis of sewage sludge, it is concluded that the optimal operating temperature is 200oC.
Agricultural income is calculated with producer price, output and management cost. This study compared organic farming with conventional one for agricultural income, producer price and output by items. And then it proposed the method of item selection and crop system from a diversification point of view. The coefficient of variation to producer prices in organic farming was 4.7%, and conventional one was 30.3% because organic products have been produced in a system of contract farming with consumers’" cooperative. This result means the price of organic products is stabler than that of conventional price. And agricultural income of organic farming has been generally known more than that of conventional one. However, agricultural gross income of conventional farming was more than that of organic one by 20.3% in 2010. It was caused by output reduction of a few items(fer example; onion, large green onion, potato and young pumpkin) due to freak weather conditions and constant producer price for several years in organic farming. In order to increase agricultural income, appropriate crop selection and system should be introduced to organic farming. A principal crop is the rice plant and 2 subordinate crops are dry crops at bare field and greenhouse respectively. Thus 5 crop systems that agricultural gross income are relatively increased larger among 15 crop systems estimated are rice+ginger+cucumber, rice+ginger+tomato, rice+large green onion+cucumber, rice+sweet potato+cucumber and rice+onion+ cucumber.
In this paper, we propose a cable climbing robot which can climb up and down the cables in the bridges. The robot mechanism consists of three parts: a wheel based driving mechanism, adhesion mechanism, and safe landing mechanism. The wheel based driving mechanism is driven by tooth clutches and motors. The adhesion mechanism plays the role of maintaining adhesion force by a combination of pantograph, ball screw, and springs even when the power is lost. The safe landing mechanism is developed for guaranteeing the safety of the robot during operations on cables. It can make the robot fall down with reduced speed by dissipating the gravitational forces. The robot mechanism is designed and manufactured for validating its effectiveness.
The characteristics of grounds influences on the safety of stone bridge structure. Therefore, this study performs the modelling and analysis considering the formation of soft ground. Also, this study evaluates the structural performance through the design variables according to the characteristics of soft ground.
This paper describes the structural behavior of insulated concrete wall panels with no-bond stress insulation. That panels reinforced with fiber reinforced polymer (FRP) truss shear connector to achieve composite action of inner and outer concrete wythes. Main test variable is bond stress. According to the test result, the shear capacity of increased due to bond stress and reinforced with FRP truss shear connector.
This paper describes the structural behavior of insulated concrete wall panels with EPS insulation. That panels reinforced with Fiber Reinforced Polymer (FRP) truss shear connector to achieve composite action of inner and outer concrete wythes. Main test variables are FRP cross section, width and picth. According to the test result, the shear capacity of increased due to reinforced with FRP truss shear connector. And width 12, 18 mm shear connector need more than 30 mm experiments about reclamation deep.
Mostly, solar panel support structure has been constructed as flat-type structure. But, it is not harmonized with the existing buildings. Therefore, this study presents the curved support structures and performs the structural analysis for the selection of member size. Also, the structural safety is evaluated through joint experiments and finite element analysis.
통합형 화산재해 대응시스템 플랫폼이 가져야할 아키텍처 요건과 각 기관에서 개발된 컴포넌트를 통합 연계할 수 있는 아키텍처 모델을 제시하여 화산재해 의사결정지원 시스템의 근간이 되는 통합형 화산재해 대응 시스템 플랫폼 설계를 통해 의사결정 지원 및 재난대응 표출이 가능하도록 아키텍처 설계할 수 있는 참조모델을 연구하고, 최종시스템 사용자의 사용성 및 편리성을 도모하고 화산재해 연구업무의 환경을 수용할 수 있도록 한다. 화산폭발 전조정보 수집 등 유관기관(기상청, 행정기관 등)과의 자료 공유 및 연계방안 수립을 위해 설계된 통합형 플랫폼의 아키텍처를 소개한다.