• 한국자동차공학회논문집
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• 제15권6호
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• pp.137-143
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• 2007

An object of this study is to understand the application characteristics in accordance with changes of EGR rate, applying BD20 reformed by ultrasonic energy irradiation to common-rail diesel engine. BD containing about 10% oxygen has attracted attention due to soaring crude oil prices and environmental pollution. This oxygen decreases soot by promoting combustion, but it also increases NOx. To make up for this problem, an EGR system is applied so that NOx might be decreased. In that case, engine power is lowered and exhaust gas is raised. However, the reformed fuel by ultrasonic energy irradiation is changed physically and chemically, promotes combustion, and thus solves such a problem. As the results of the experimemt, we could identify the optimum EGR rate by investigating the engine performance and the characteristics of exhaust materials in accordance with the EGR rate after ultrasonic energy irradiation to BD20 and applying it to common-rail diesel engine. The optimum EGR rate that can satisfy both engine performance and characteristics of exhaust materials was in the range of 15%.

• 자원리싸이클링
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• 제19권3호
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• pp.16-23
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• 2010

최근 고유가 시대로 접어들면서 연탄의 사용량이 급격하게 증가하고 있어 이때 발생되는 연탄재의 친환경적인 순화자원화 기술개발이 필요하게 되었다. 연탄재에는 가연성분인 미연탄소와 고온열적특성이 우수한 뮬라이트 성분이 다량 함유되어 있어 소성 에코벽돌의 원료로 적합하다고 판단된다. 이 연구의 목적은 연탄재에 함유되어 있는 미연탄소가 소성 에코벽돌의 특성에 어떠한 영향을 미치는 가를 파악하는데 있었다. 미연탄소 함량 10.5 wt%인 연탄재 50 wt%와 폐유리 50 wt%의 배합비율로 제조한 에코벽돌을 $950^{\circ}C$로 소성한 시험체의 압축강도는 소성 점토벽돌 국내규격(KS L 4201)의 1종 규격에 해당하였다. 특히, 미연탄소 함량이 1.0 wt%인 연탄재의 배합비율을 70 wt%까지 증가시켜 제조한 소성 에코벽돌 시험체의 압축강도는 소성 점토벽돌 1종 규격에 해당하였다.

• 한국해양공학회지
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• 제28권1호
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• pp.20-27
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• 2014

In view of the importance of material reduction and rational structural design due to the rapid increase in oil and steel prices, an optimized structural hybrid design system for the doubler plate of a ship's hull structure was developed. A direct design process by a structural designer was added to this developed optimized system to increase the design efficiency and provide a way of directly inserting a designer's decisions into the design system process. As the first step of the doubler design system development, the design formulas used in doubler design system were introduced. Based on the introduction of influence coefficients $K_{t_c}$ $K_{t_d}$, $K_{b_d}$ and $K_{a_d}$ according to the variations in the doubler length, breadth, doubler thickness, and average corrosion thickness of the main plate, the design formulas for an equivalent plate thickness were developed, and a hybrid design system using these formulas was suggested for the slender doubler plate of a ship structure subjected to a longitudinal in-plane compression load. By using this developed design system, a more rational doubler plate design can be expected considering the efficient reinforcement of the plate members of ship structures. Additionally, a more detailed structural analysis through local strength evaluations will be performed to verify the efficiency of the optimum structural design for the doubler plate.

• 한국전자통신학회논문지
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• 제11권4호
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• pp.411-420
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• 2016

석탄과 석유를 대신할 새로운 대체 에너지의 연구 및 개발은 지난 수년간 계속해서 연구되고 있다. 최근엔 유한 에너지 가격 상승으로 인하여 무공해 신재생 에너지의 관심이 증가하고 있다. 특히 기존에 활발히 연구되고 상용화된 신재생 에너지 분야 중 태양에너지는 태양광 에너지에 주된 연구가 이루어져 있다. 그러나 태양광 에너지의 효율성은 이미 포화상태에 도달하였다. 이에 본 논문에서는 태양광이 아닌 태양열 에너지를 활용할 수 있는 태양광 추적형 파라볼릭 집열장치를 제안한다. 제안하는 태양열 집열장치는 효과적으로 태양열을 집열하기 위하여 파라볼릭 형태로 제안하고, 계절 및 시기에 따른 태양의 위치변화를 감지할 수 있도록 5축 센서 방식의 태양광 추적형 트래킹 기술을 결합한 태양열 집열장치의 프로토타입을 제안한다. 또한 집열장치의 효율적인 관리를 위하여 관리자 인터페이스를 설계 및 구현한다.

• 조명전기설비학회논문지
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• 제24권2호
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• pp.77-85
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• 2010

최근, LCD(Liquid Crystal Display) 산업에서 클린룸의 규모가 커짐에 따라 Stocker 시스템의 사이즈가 커지고 길이가 장거리화 되고 있다. 이에 제조업체는 생산수율을 높이기 위해 Stocker 시스템의 전체 택타임을 줄이기 위한 방안으로 Stocker 시스템의 속도 증가와 고유가 시대에 여러 장비들에 대한 에너지 절약을 통한 공장 운영비용이 최소화되도록 요구하고 있다. 따라서 본 논문은 차세대 Stocker 시스템의 에너지 절감과 이송 속도증가에 따른 고효율 비접촉 전원시스템(CPS, Contactless Power Supply)의 최적설계를 제안하고, 에너지 절감을 위한 비접촉 전원시스템의 시제품을 제작하여 부하인 크레인의 여러 운전 패턴에 따른 비접촉 전원시스템의 실증시험과 입/출력 특성, 효율 개선에 따른 최적화로 개발된 비접촉 전원 시스템의 에너지 절감 효과에 대하여 서술하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권7호
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• pp.814-820
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• 2014

문명의 발전과 도시화, 산업화를 통하여 인류는 의식주의 해결뿐 아니라 더 낳은 생활환경을 추구하였다. 그 결과 냉동 및 공조 분야의 연구와 개발이 활발히 진행되어 왔다. 하지만 인류는 21세기에 들어 상승하는 고유가와 환경문제를 더 이상 간과할 수 없게 되었다. 그 대안으로, 해수의 열원을 이용한 열펌프의 개발이 진행되었다. 본 논문에서는 2010년의 해수와 대기의 온도를 분석하여 열펌프의 국내적용을 위한 성능평가 시뮬레이션을 HYSYS 프로그램을 이용하여 전수식과 전공기식에 적용하였다. 그 결과, 총 평균 성능계수는 전수식에서 3.37 그리고 전공기식에서 3.48을 기록하였다. 이와 같은 결과로 해수열원을 이용한 열펌프 시스템이 국내사용에 적합함을 알 수 있었다.

• 수산해양기술연구
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• 제47권4호
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• pp.435-442
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• 2011

In an attempt to respond to the increase in international oil prices and reduce operating expenses, ship remodeling was carried out on a 740ton class tuna purse seiner. To strengthen the competitiveness of the fisheries industry by improving vessel performance, a bulbous bow was newly equipped. The slipway and rudder area were also lengthened and enlarged with the propeller and main engine remained unchanged. To reduce the hull resistance, a circle type bulbous bow was attached on the hull behind bow thruster and thus the cost for exchanging electrical equipment for bow thruster was reduced. The new rudder area was expanded 15% more than the old one within the extent that the existing mechanical control part and rudder stock were not changed. To prevent fishing net damage and stabilize wake field, slipway was lengthened to the optimal position. All of the new design of remodeling parts went through the model tests in towing tank and CWC. Besides resistance test, all of necessary model test results were delivered for hydrodynamic character for the modified ship. The maneuvering simulation to verify that the remodeled ship satisfies the IMO rules was performed in both zigzag and turning tests. The estimated resistance with new bulbous bow and lengthened stern was reduced by 4.8% in the 2-dimensional analysis and 17.4% in the 3-dimensional analysis in comparison of conventional ship. The average reduction of resistance was estimated about 10%. Maneuvering character of modified hull form was found to satisfy all regulations under IMO. The remodeling of tuna purse seiner can not only improve fishing performance but also contribute to reduction of operating cost by saving energy for the fisheries industry.

• 한국대기환경학회지
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• 제28권6호
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• pp.656-665
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• 2012

Recently, yearly production of SRF (Solid Recovered Fuel) as an alternative fuel has been rapidly increasing because of the limited waste disposal, rise in oil prices and reduction of greenhouse gas emission. However, SRF using facilities are excluded from the National Air Pollutant Emission Estimation because SRF using facilities are not yet included among the SCC (Source Classification Code). The purpose of this research was to estimate the emission and emission factor of SRF using facilities' PM and $NO_x$, in order to investigate whether or not they are included in the National Air Pollutant Emission Estimation. The emission factors of SRF using facilities' PM and $NO_x$ are calculated as 0.216 kg/ton, and 3.970 kg/ton, and the emission was estimated based on the yearly total SRF usage of 2011. The results above was 18.7% for PM and 12.8% for $NO_x$ emissions from combustion facility (SCC2) in manufacturing industry combustion (SCC1) of CAPSS. If CAPSS estimate the emission by adding SCC on unlisted SRF in case of Boiler (SCC3) fuel, both PM and $NO_x$'s emissions would increase by 15.8% and 11.3% compare to the emissions for the existing combustion facility. As a result, emissions caused by SRF should be considered when calculating the National Air Pollutant Emission Estimation. In addition, further researches to develop emission factor and improve subdivided SCC should be done in the future, for the accurate and reliable estimation of National Emission.

• 대한조선학회논문집
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• 제51권4호
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• pp.334-341
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• 2014

Due to the rise of international oil prices, with the continued increase of vessel operating costs, profitability has gradually deteriorated in the some case of South Korea ferry shipping. Therefore, it is necessary to improve the resistance performance of passenger ship. Goose neck bulb can be one of the methods to improve the resistance performance of passenger ship. Goose neck bulb has been applied to passenger ships operated in Europe and large cruise line. But there is no application example in the passenger ship to be operated on a regular basis in the sea near Korea. It is needed to provide reference data that can be applied efficiently goose neck bulb on the medium-sized passenger ships. This study, intended for the medium-sized passenger ship operated short international routes, presents the design of the hull form that goose neck bulb has been applied. And the resistance performance of the designed hull confirmed by numerical simulation. The numerical simulation is performed while changing the local shape of the goose neck depending on the bulb parameters. This study finds bulb parameters and their range that can affect the resistance performance. Thus, it is possible to provide a foundation to develop the optimal design technique and regression analysis on the resistance performance and goose neck bulb.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.24-24
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• 2018

Degraded plantation forests are increasing because of unfavorable forestry conditions prevailing in Japan, including falling timber prices, increasing operational costs, and aging and declining forestry workforce. To remedy this situation, appropriate management strategy is required. This study introduces the challenges of Odai Town, Mie Prefecture that employed a new management strategy by evaluating site suitability for conifer forests and that proposes a new forest management regime of planting deciduous trees in unsuitable sites. The site suitability for conifer forests was evaluated from two aspects: the natural site conditions and the relationship among site conditions, growth, and damage by Anaglyptus subfasciatus Pic. in Cryptomeria japonica D. Don and Chamaecyparis obtusa Sieb. Et Zucc. forests. By analyzing the relationship among site conditions, growth, and insect damage based on field data obtained in plantation forests, growth evaluation and insect damage evaluation maps were developed. Based on the natural forest investigation, natural site condition maps for C. japonica and C. obtusa were established. Furthermore, by integrating these evaluation maps with the forest road maps showing the accessibility to the forest, the forest management regime for the whole plantation area of Odai Town was established. The forest management regime map indicates the sites suitable for forestry: suitable for long-rotation, short-rotation, and potential sites for short-rotation. The sites unsuitable for forestry were considered to be more suitable for broadleaved forests. Clear-cutting was conducted in a small area and different seral stage saplings (approximately 20 deciduous tree species) suitable to the site conditions were planted in an area of $80-120m^2$ protected by deer-fences. This might establish a forest composed of many species with a multilayer vertical forest structure in a short period. The planted saplings were distributed neither randomly nor uniformly to reflect the natural distribution of trees in the forest. A challenge to develop new products using the deciduous trees has started, such as wood chips for preparing smoked food, essential oil, and deodorizer. As these challenges have just begun, their effects on enhancing sustainable resource management are still being monitored. Even with the challenges, this regime can be of high value as a management strategy to remedy the situation of expansion of degraded forests in Japan.