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        검색결과 21

        2.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the capacity of renewable power generation facilities rapidly increases, the variability of electric power system and gas turbine power generation is also increasing. Therefore, problems may occur that require urgent repair while the gas turbine rotor is stopped. When the gas turbine rotor turning is stopped and then restarted, if the turning period is not appropriate, severe vibration may occur due to rotor bending. As a result of the experiment, it was confirmed that normal operation is possible when the gap data measured at the start of rotor turning after maintenance work is similar to the existing value. And the vibration value at the start of rotor turning was lower as the rotor temperature was lower or the stop period was shorter.
        4,000원
        3.
        2023.05 구독 인증기관·개인회원 무료
        A plasma torch is a kind of equipment that utilizes an electric arc to dissociate a gas and transfer an electric energy to the gas to generate very high temperature flame. KHNP-CRI has been developed the Plasma Torch Melter (PTM) to reduce radioactive waste disposal volumes and drop the radiation level of wastes. As you guess, there is required condition for proper start-up operation like current, voltage, plasma gas flow, cooling water flow, temperature in melter and so on. Thus, the optimum start-up operation condition of plasma torch will be estimated experimentally in this paper.
        4.
        2023.05 구독 인증기관·개인회원 무료
        As if the wet storage of Spent Nuclear Fuel (SNF) becomes saturated, a transition from wet storage to dry storage could be required. The first process for dry storage is to move SNF from the wet storage into a canister for dry storage, and secondly perform a drying process to remove the moisture in the canister to prevent a potential impact such as deterioration of cladding or corrosion of the interior material. Nuclear Regulatory Commission (NRC) accepts the conditions describing the adequate dryness state that remain below the pressure of 3 Torr for 30 minutes in the drying process. That is, the most pressure of water vapor that may exist inside the canister is 3 Torr. If it is maintained below 3 Torr, it can be determined that the dryness criterion is satisfied. Based on this, relative humidity and dew point trends can be identified. Relative Humidity (RH) is calculated by dividing the vapor pressure by the saturated vapor pressure. Here, if the vapor pressure is fixed at 3 Torr, which is the dryness criterion value, the relative humidity has a value according to the saturated vapor pressure. Saturated vapor pressure is a value that varies with temperature, so relative humidity varies with temperature. On the other hand, the dew point temperature has a value according to the water vapor pressure. Therefore, when the internal temperature of the canister is 120°C and the water vapor pressure is 3 Torr, the relative humidity is 0.2% and the dew point temperature is -4.4°C. We will confirm the suitability of the dryness criterion through the drying tests, and secure a technology that can measure and evaluate the amount of moisture remaining inside the canister.
        6.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, it is conducted to understand the heating performance and compressor operation characteristics according to 7 indoor unit combinations and 3 setting temperatures of the inverter multi-heat pump under heating standard temperature conditions. Heating capacity, COP and compressor frequency are investigated using the multi-calorimeter. The indoor unit combinations are simultaneous operation(A+B+C), partial operation(A+C, A+B, B+C) and independent operation(A, B, C), and the setting temperature is 20, 21, and 30°C. Since the increase in the setting temperature increases the compress frequency, the heating capacity increases, but COP decreases due to the increase in power consumption. The frequency increases as the indoor unit combination capacity increases, and decreases as the setting temperature decreases in the steady state.
        4,000원
        9.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Coupling is commonly used as a mechanical fastener to connect the turbine housing and the bearing housing in a turbocharger assembly. The finite element analysis was used to predict the structural behaviors of the coupling system, which could be caused by the bolt clamping force in the assembly process and the thermal deformation during turbocharger operation. The back plate is used to prevent gas leakage from the turbine housing to the bearing housing while the fixed pin is inserted to set the reference position between the two parts. Thus, in order to predict the mechanical behaviors of the coupling system numerically, the temperature distributions were calculated by heat transfer analysis based on the rated speed of the diesel engine. As a result of analyzing the structural characteristics of the turbocharger, the contact pressure of the back plate was influenced by thermal deformations whereas the bending deformation of the fixed pin was affected by the thermal deformation and the pin position.
        4,000원
        10.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Warpage of injection molded product is caused by non-uniform shrinkage and residual stress. A method of removing uneven molding shrinkage and residual stress is to remove the defective factor to Uniform cooling of products. Warpages for part designs have been investigated in this study according to the injection molding conditions for amorphous ABS and crystalline PP by the rapid cooling and heating system. Experimental results showed that the crystalline resin was more warped than amorphous resin, Warpages have been observed in the regions of the part, near gate region and flow direction region.
        4,000원
        11.
        2016.11 구독 인증기관 무료, 개인회원 유료
        When weapon system is designed and developed, a reliability is one of important factors to determine the development goal. The reliability analysis of the weapon system and equipment is based on MIL Specification, MIL-HDBK-217F and MIL-HDBK-338B. And the weapon system is operated on various environments by operating concept of the military using the weapon system. This study, at first, present failure rate by PSA comparing with failure rates by PCM, the different reliability analysis method, for same CCA(Circuit Card Assembly). And the study present change of reliability analysis results for CCA on various operation environment condition..
        4,000원
        12.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The adsorption/desorption characteristics of toluene vapors filled with activated carbon(AC) were studied. Adsorption performance of AC was investigated according to flow rate, moisture content, and other factors. The breakthrough time was shortened as the flow rate and moisture content increased. The AC loaded with toluene was regenerated by programmed heating and pressure. AC was regenerated well, as the conditions of heating temperature(80oC) and pressure(100 torr) were appropriate. Toluene is more easily removed at low temperature than through thermal desorption methods. The test of AC regeneration was carried out three times.
        4,000원
        13.
        2009.11 구독 인증기관 무료, 개인회원 유료
        This study presented a model of enterprise that operates an integrated system, and studied about an integrated element of ISO 9001:2000 and ISO 14001:2004 standard. In addition to this, it grasped what the obstacle elements are in use of an integrated system, and analyzed the effect in use of an integrated system through the survey on 58 enterprises that operate an integrated system, From the result of this study, we have known that the obstacle elements in operation of an integrated system are in lack of understanding of process, in lack of execution ability of system, in unfamiliarity of system and lack of willingness of the executives.
        5,400원
        14.
        1999.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기존의 정수처리 공정인 응집 침전 과정을 대체하여 분리막을 이용한 상수처리 시스템의 개발을 목적으로한다. 따라서 4가지 형태의 정수처리 공정과 분리막의 분획 분자량을 변화시켰을 때 막 투과수의 변화와 안정적이며 높은 투과수를 얻기 위해 필요한 운전 조건의 최적화를 실험하였다 실험결과 한외여과막이 정밀여과막보다 막 투과수 감소경향이 완만했으며 초기 투과수 회복율은 더 높았다. 수질 분석의 결과 한회여과막이 정밀 여과막보다 우수하였지만 전처리에 의한 차이는 나지 않았다. 운전 조건에 따른 flux 는 온도, 선속도가 높을수록 압력이 낮을수록 flux 감소율이 적은 경향을 나타내었다.
        4,000원
        15.
        1997.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Well-balanced meal is very important in its quantity and quality. Especially on the quantity field it becomes difficult for a foodservice operation to decide proper portion for individuals uniformly. These study was focused to setting up a proper portion by each food service operation. The results obtained were: 1. Individual consumption size from dormitory food service of college: cooked rice 282 g, soups 161 g, pot stewes 162 g, stir fries 53 g, stews 32 g, kimchies 47 g, fresh and boiled salads 43 g, one course dishies 477 g, pan broiles 44 g, meunieres 124 g. Individual consumption size from industry foodservice (white collar worker): cooked rices 228 g, soups 205 g, pot stewes 251 g, stir fries 20 g, stewes 76 g, kimchies 57 g, fresh and boiled salads 36 g, one course dishies 423 g, pan broiles 63 g, meunieres 38 g. 2. Proper portion of meal based on a statistical data is as follows: at college foodservice - cooked rices 280~290 g, soups 155~170 g, pot stewes 170 g, stir fries 60 g, stewes 35 g, kimchies 40~60 g, fresh and boiled salads 50 g, one course dishies 480 g, pan broiles 50 g, meunieres 130 g and at industry foodservice (white collar worker) - cooked rices 220~250 g, soups 210 g, pot stewes 250 g, stir fries 20 g, stewes 80 g, kimchies 60 g, fresh and boiled salads 40 g, one course dishies 430 g, pan broiles 70 g, meunieres 40 g.
        4,000원
        16.
        2017.05 서비스 종료(열람 제한)
        현재 국내에서 발생하는 음폐수의 해양투기 금지 및 음식물류 폐기물의 에너지화 정책에 따른 유기성 폐기물 육상처리의 일환으로 혐기소화를 통한 바이오가스화 시설이 지속적으로 설치 및 운영되고 있다. 그중에서도 음식물쓰레기는 처리 단가가 높고, 바이오가스 회수 잠재력 또한 높아 바이오가스화 시설의 경제성을 높여줄 유용한 폐자원으로 여겨지고 있다. 하지만 국내 발생 음식물쓰레기의 평균 고형물함량(TS)이 18~20% 수준으로 혐기소화를 통한 바이오가스화 이전에 전처리가 필수적이며, 단순 파쇄/선별을 통한 물리적 전처리만으로는 충분한 가용화가 어려운 부분이 있다. 이러한 유기성폐자원의 가용화를 위한 전처리 방법에는 가수분해/산발효를 통한 생물학적 처리, 산, 알칼리, 오존 등을 통한 화학적 처리, 초음파, 열, 압축 등에 의한 물리적 처리 등이 있는데 본 연구에서는 물리적 처리방법 중 하나인 열가수분해를 통한 음식물쓰레기의 가용화효율을 분석하였다. 이를 위해 1차로 물리적 파쇄/선별 처리한 음식물쓰레기에 대해 다양한 운전 조건(온도, 압력 변화)으로 열가수분해를 실시하여 각 운전조건별 음식물쓰레기 성상변화를 분석함으로써 음식물쓰레기 열가수분해를 위한 최적 운전조건을 도출하고자 하였다.
        17.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to draw implications and critical success factors by surveying and analysing practice cases of green care in south Korea. To achieve the object of this study, many valuable cases were checked through preceding researches and internet informations. Case study targets were divided into side-work farmer type, professional farmer type, and Institution directed type, and then case study surveys were performed by each type. Every case has the natural environment in common, and tries to satisfy users’s demands and to give the opportunity to communicate. Especially, the strong motivation, mind, and entrepreneurship of operators are very important factors for green care. If the development of government supporting policies and related education programs are accompanied with lots of potential such as Korean oriental medicine, rural tourism village, and sixth industry project, it will be possible to introduce and manage green care successfully.
        18.
        2013.04 KCI 등재 서비스 종료(열람 제한)
        This work presents an experimental study of the influence of lifting velocity on cake formation during filtration. For design of hot gas cleanup system using ceramic filter reactor, the most important consideration is coating conditions of sorbent in filter surface (for example : lifting velocity, coating weight of sorbent, pulsing interval and removal effect for dechlorination and desulfurization). We studied the optimum operation condition as paticle size and lifting velocity using a ceramic filter reactor at 550oC. Based on the results obtained during cold and hot test, optimum lifting velocity in a ceramic filter reactor was selected 0.68 m/s. Also, the removal behaviour of the ceramic filter during filtration was studied using differential pressure. Optimum removal efficiency for dechlorination and desulfurization accomplished at differential pressure condition over 74 mmH2O.
        19.
        2010.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서 하역크레인을 장착하여 모선과 연안항만간 컨테이너를 단거리 운송하는 것으로 새로운 개념의 해상운송시스템인 모바일하버를 소개하였다. 초대형 컨테이너선박이 직접 연안항만에 접이안하는 대신에 모바일하버가 해안에서 일정거리 이격되어 모선이 정박하기에 수심여건이 양호한 작업장까지만 이동한다. 따라서, 모바일하버의 적용을 위한 국내 무역항의 해안환경, 기술적 조건 및 한계에 대한 조사는 필연적 과정이다. 모바일하버의 접근성을 파악하기 위하여 환경조건, 화물하역처리능력, 해상교통량 및 교통류를 해상교통시뮬레이션 및 가상항로표지시스템의 툴을 사용하여 분석하였다. 수집한 정보의 분석과 적용서의 평가를 통해 최적수준의 남해안 및 동해안 무역항에 대한 모바일하버 정박장은 (1) 기상 및 해상자연환경조건면에서 마산항, 울산항, 부산신항의 순으로, (2) 해상교통 및 수역시설여건의 조건에서는 목포, 부산신항, 동해묵호항의 순으로, (3) 화물처리의 현장능력 및 지역무역항의 운영실태분석으로는 부산권, 여수광양권, 목포권으로 나타났다. 본 연구를 통해 최적의 항만 및 작업장 선정을 위한 기준을 제시하였으며, 모바일하버가 현장에 적용되기 위해서는 초대형선박과 모바일하버의 접안 및 화물작업이 이루어지는 해역에서 해상교통안전을 확보하기 위한 선박자동식별시스템 등 가상항행보조시설이 도입되어야 할 것으로 본다.
        20.
        2004.12 KCI 등재 서비스 종료(열람 제한)
        다양한 내부경계를 포함하는 폐합형 하천수계에 대한 부정류 계산모형을 개발하였다. 계산모형은 폐합형 수계모형으로서, 계산기법으로는 Preissmann의 4점 음해법과 폐합형 double sweep 알고리즘에 근거한 모형을 사용하였다. 또한 댐 및 수중보 등의 수공구조물에서 발생할 수 있는 월류흐름, 오리피스형 흐름 등에 대한 모의가 가능하도록 하고, Auto ROM에 의한 댐에서의 홍수조절 방안을 내부경계 조건으로 포함하여 홍수시 운영조건에 대한 모의가
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