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        검색결과 35

        4.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        선박용 엔진에서 배출되는 배기가스에는 다량의 수분과 미세먼지를 포함하고 있다. 미세먼지에는 여과성 미세먼지와 배기 배 출 후 액상으로 변화하는 응축성 미세먼지가 포함되어 있으며 배출 전에 걸러지는 고체상 미세먼지보다 응축성 미세먼지가 더 많은 것으 로 보고되고 있다. 본 연구에서는 배기가스의 배기열과 수분을 회수하고 응축성 미세먼지를 제거하기 위한 실험장치를 실험실 내의 가스 보일러 배기가스를 이용하여 테스트 하였다. 배기가스는 1차적으로 냉각방식으로 수분과 응축성 미세먼지가 제거되고 2차적으로 흡수제 방식에 의해 추가적으로 수분이 제거되었다. 상대습도 측정에 의한 배기가스 수분 제거율을 계산하면 1단계 배기냉각 방식으로 73%, 2단 계 흡수제 방식으로 90% 제거되는 것으로 측정되었다. 이 과정에서 응축성 미세먼지는 80~90% 제거되는 것으로 측정되었다. 개발 시스템 에 의해 회수된 열은 공정열로 활용할 수 있으며, 회수된 물은 수처리 과정을 통해 공정수로 활용할 수 있다. 또한 현재 관리 규제가 되고 있지 않지만 미세먼지의 주요 원인인 응축성 미세먼지를 효과적으로 제거할 수 있을 것으로 기대된다.
        4,000원
        6.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the distribution characteristics of particulate matter (PM) in subway platforms were investigated, and the performance of hybrid filter systems was determined through the removal efficiency of PM according to various flow rates and filter structures. The hybrid filter systems were constructed in magnetic systems as (Magnet-Magnet (MM) filters and Magnet-Cascade (MC) filters). PM removal efficiencies of these filters were investigated at a subway platform for three days including weekdays and weekends. The compositions of collected PM were also analyzed. Based on the PM measurement in the subway platforms, it was confirmed that the operation of trains had a significant effect on the increase of PM concentration, and a large number of PMs were less than 1 μm in size. For the MC filter, the removal efficiency of PM1 based on the number of particles was up to 30.5%, demonstrating a relatively high removal efficiency in comparison with the MM filter. In terms of PM10, PM removal efficiencies of the MC filter with respect to the mass concentration and the number of particles were 48.3% and 14.5%, respectively. For the MC filter, it was found that the PM removal efficiency was enhanced with the increase in the flow rate. Moreover, the relatively large particle size PM (i.e., 7.5 μm - 10 μm) denoted a maximum removal efficiency of 97% in terms of the number of particles. All PMs collected by the filter were Fecontaining PMs. As a field experiment using the hybrid filter, the applicability of magnetic particle control technology was approved. Based on this result, it is expected that this study will be used as background research for the development of fine dust control technologies in a subway environment.
        4,000원
        11.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A hybrid mid-story seismic isolation system with a smart damper has been proposed to mitigate seismic responses of tall buildings. Based on previous research, a hybrid mid-story seismic isolation system can provide effective control performance for reduction of seismic responses of tall buildings. Structural design of the hybrid mid-story seismic isolation system is generally performed after completion of structural design of a building structure. This design concept is called as an iterative design which is a general design process for structures and control devices. In the iterative design process, optimal design solution for the structure and control system is changed at each design stage. To solve this problem, the integrated optimal design method for the hybrid mid-story seismic isolation system and building structure was proposed in this study. An existing building with mid-story isolation system, i.e. Shiodome Sumitomo Building, was selected as an example structure for more realistic study. The hybrid mid-story isolation system in this study was composed of MR (magnetorheological) dampers. The stiffnessess and damping coefficients of the example building, maximum capacity of MR damper, and stiffness of isolation bearing were simultaneously optimized. Multi-objective genetic optimization method was employed for the simultaneous optimization of the example structure and the mid-story seismic isolation system. The optimization results show that the simultaneous optimization method can provide better control performance than the passive mid-story isolation system with reduction of structural materials.
        4,000원
        12.
        2018.11 구독 인증기관·개인회원 무료
        In this study, various physical cleaning methods such as physical washing and osmotic backwash, were performed to understand membrane fouling characteristics by employing real secondary wastewater effluent (SWWE). In addition, microfiltration (MF) and ultrafiltration (UF) pretreatments were compared to maximize removal of organic matter and to control membrane fouling efficiently. Organic foulants deposited on the active layer of FO membrane were observed by fouling behavior test. The relationship between concentrations of natural organic matter and membrane fouling was also investigated from the bench-scale FO tests. Finally, by quantitative analysis of correlations between foulants and fouling reversibility with the modified fouling index (MFI), we identified the applicability of MFI in predicting FO intake water fouling potential.
        13.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A base isolation system is widely used to reduce seismic responses of low-rise buildings. This system cannot be effectively applied to high-rise buildings because the initial stiffness of the high-rise building with the base isolation system maintains almost the same as the building without the base isolation system to set the yield shear force of the base isolation system larger than the design wind load. To solve this problem, the mid-story isolation system was proposed and applied to many buildings. The mid-story isolation system has two major objectives; first to reduce peak story drift and second to reduce peak drift of the isolation story. Usually, these two objectives are in conflict. In this study, a hybrid mid-story isolation system for a tall building is proposed. A MR (magnetorheological) damper was used to develop the hybrid mid-story isolation system. An existing building with mid-story isolation system, that is “Shiodome Sumitomo Building” a high rise building having a large atrium in the lower levels, was used for control performance evaluation of the hybrid mid-story isolation system. Fuzzy logic controller and genetic algorithm were used to develop the control algorithm for the hybrid mid-story isolation system. It can be seen from analytical results that the hybrid mid-story isolation system can provide better control performance than the ordinary mid-story isolation system and the design process developed in this study is useful for preliminary design of the hybrid mid-story isolation system for a tall building.
        4,000원
        14.
        2018.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.
        4,000원
        15.
        2017.11 구독 인증기관·개인회원 무료
        Polymer electrolyte membrane (PEM) is one of key elements to determine both electrochemical performances and lifetimes of fuel cell electric vehicles (FCEVs). PEM is exposed to a variety of dynamic stimuli (e.g., temperature, humidity, pressure, fuel gases and so on) under their operation conditions and meets unavoidable mechanical damages derived from unequal pressure difference between anode and cathode feed gases. Even though there have been approaches to evaluate the mechanical strength of PEM materials, most of the trials could provide static information on their mechanical strength. In this study, a pressure-loaded blister hybrid system connected with gas chromatography was developed to disclose the efficacy of the system as an evaluation tool of dynamic PEM strength under realistic FCEV operation conditions.
        16.
        2017.11 구독 인증기관 무료, 개인회원 유료
        Domestic fishing villages' net profit has consistently dropped down in recently, and currently it is down to 16.4%.This paper develop and increase fishing profit as this project will decrease 20% of the operation cost and eventually vitalize the fishing villages' economy. Especially, it could be an alternative solution to the constant requests of WTO (World Trade Organization) and UN ECOSOC (UN Economic and Social Council) to stop cross subsidization of marine products. IMO (International Maritime Organization) is concerned about air pollution caused by carbon dioxide production, and it strongly suggests on decreasing carbon dioxide discharge level. This paper will help protect ocean ecology as it will not only decrease various types of oil usage but also promote alternative technology solution. Also Increase business' profit by selling ocean and other related business parts and factors. Low speed electric car applies high performance level of motor and motor control devices. Among those, about 20% is the original cost of motor and motor control devices. Therefor entering low speed electric car market, parts sales and sales will increase.
        4,800원
        17.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To overcome recent emission regulation, various hybrid systems are being developed. In the E-4WD(electric four wheel drive) system, the engine and transmission drive the front wheel, electric motor and single reduction gear drive the rear wheel. As the gear ratio of the reduction gear set determines the electric motor's operating point, the gear ratio is important to enhancement efficiency of hybrid system. This study is to analyze motor reduction gear ratio's influence on E-4WD hybrid system for optimized efficiency and driving performance. Fuel economy, operating point of power source and hybrid mode are analyzed using simulation developed with dynamic programming method.
        4,000원
        18.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The limitations and problems of the rechargeable battery and short mileage per one electric charging have not been overcome at the electric vehicles. To solve these problems, the hybrid vehicle has been developed by securing the performance of automotive with the conventional internal combustion engine and the environmental benefit. Meanwhile, the electric UTV (utility terrain vehicle) which has this environmental benefit has been widely used for factories, parks, leisure and agricultural areas. In this study, the electric UTV was fabricated and attached the auxiliary power drive systems including the photovoltaic power generation system into this electric vehicle in order to make up the hybrid (motor + photovoltaic) vehicle system. As the range of the hybrid UTV would be extended over 20% than that of the existing golf cart per one electric charging through this successful development, the dynamic stiffness was improved through light-weight body design.
        4,000원
        19.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because of environmental pollution and lack of resources, necessity of energy efficiency improvement and reduction of exhaust gas emission and CO2 have grown in importance. Therefore a lot of studies are conducted for HEV(hybrid electric vehicle) and PHEV(plug-in hybrid electric vehicle). In addition, automobile companies are researching and manufacturing HEV and PHEV. Due to cost and time problem, simulation is preferred than experimental test to find better component size for efficiency improvement. In this research, backward simulation program is developed base on Dynamic Programming. Using this simulation program, fuel economy sensitivities for each parameter are analyzed and compared. Fuel economy is measured for a combined cycle that is calculated from FTP-75 and HWFET cycle. The target parameters are front/rear power train efficiency, drag coefficient, vehicle mass, rolling resistance coefficient, tire radius, center of gravity. The most sensitive parameter is front power train efficiency and second is drag coefficient. Rear power train efficiency, vehicle mass, rolling resistance coefficient are third, forth and fifth. By comparing sensitivities, we can choose a better way to improve fuel economy of HEV.
        4,000원
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