• Journal of the Korean Society of Combustion
• /
• v.14 no.4
• /
• pp.17-24
• /
• 2009

Reburning is one of the most useful technologies for reducing nitric oxide in economically and technically. The reburning process was demonstrated as an effective NOx reduction method through injection of a secondary hydrocarbon fuel. An experimental study has been conducted to evaluate the effect of biomass reburning on NOx and CO formation in a light oil flamed combustion furnace. Reburning tests on NOx reduction of air-carried rice husk powder as the reburn fuel and light oil as the main fuel were performed in flames stabilized by a co-flow swirl and fuel staged burner, which was mounted at the front of the furnace. The results included flue gas emissions and temperature distribution in the furnace for several kinds of experimental conditions. It was observed clearly that NOx concentrations in the exhaust have considerably decreased due to effect of biomass reburning. The maximum NOx reduction rate was 42% when the reburn fuel fraction was 0.18. The CO emissions were kept under 42 ppmv in all experimental tests. And this paper makes clear that in order to decrease NOx concentration in the exhaust when the biomass reburning system is adapted, the control of some factors such as reburn fuel fraction and reburn zone fraction is very important.

• The KSFM Journal of Fluid Machinery
• /
• v.17 no.1
• /
• pp.12-21
• /
• 2014

An organic Rankine cycle was analyzed to work at the optimal operating point when the heat source is fluctuated. R245fa was adopted as a working fluid, and an axial-type turbine as expander on the cycle was designed to convert the heat energy to the electricity since the turbo-type expander works at off-design points better than the positive displacement-type expander. A supersonic nozzle was designed to increase the spouting velocity because a higher spouting velocity can produce more output power. They were designed by the method of characteristics for the operating fluid of R245fa. Three different cases, such as various spouting velocities, various inlet total temperatures, and various nozzle numbers, were studied. From these results, an optimal operating cycle can be designed with the organic Rankine cycle when the available heat source as renewable energy is low-grade temperature and fluctuated.

• Journal of Fisheries and Marine Sciences Education
• /
• v.16 no.1
• /
• pp.1-10
• /
• 2004

The department of education developed editing data of fisheries and shipping high school subject in 1987. But as change to informational society, the new term and predicate were built on a textbook of fisheries and shipping that was not in the past. Terms came into being in this way, it was used indiscreetly by spending a different expression on a textbook. In this study based on currently subject of fisheries and shipping high school 36books, examined an elementary school junior high school and a definition related term in order to solve these problems. Specialist on each field selected term and the predicate which is objective and proper. Especially field of fisheries and shipping uses a japanese term as it is. So there are a lot of the terms that is hard for students. Using these terms yet, the term that meaning delivery is uncertain and hard expression is going to carry out role to convert to a clear and easy term through this study.

• Journal of Fisheries and Marine Sciences Education
• /
• v.24 no.6
• /
• pp.872-883
• /
• 2012

Generally the determination of turning basin for vessels of entering & sailing in the berth has been considered in the design standard of harbor construction rules of the port. In this regard, the turning basin has been determined by the max size of entering vessel of the berth/port. But the size of turning basin may considered the ship's maneuvering ability, operator's skillful power, mooring equipments of the berth, arrangement of the fairway and the environment condition of weather & seas around the designated port area. So this paper suggested the optimum size of turning basin after studying the harbour design rules of the advanced marine countries and using by maneuvering simulator for turning basin size and also evaluated the design standard of harbor construction rules and minimum size of turning basin against ship's length at the Gangjung civil/naval port of Jeju Island.

• Journal of ILASS-Korea
• /
• v.17 no.3
• /
• pp.121-127
• /
• 2012

The study is to investigate the mixing stability, fuel properties, and macroscopic spray characteristics of diesel-gasoline blended fuels in a common-rail injection system of a diesel engine. The test fuels were mixed diesel with gasoline fuel, which were based volume fraction of gasoline from 0 to 100% in 20% intervals. In order to analyze the blended effect of gasoline to diesel fuel, the properties of test fuels such as density, viscosity, and surface tension were measured. In addition, the spray behavior characteristics were studied by investigating the spray tip penetration and spray angle using a spray images through a spray visualization system. It was revealed that the density, kinematic viscosity and surface tension of diesel-gasoline blending fuels were decreased with the increase of gasoline fuel. The injection quantity of test fuels were almost similar level at short energizing duration condition. On the other hand, the increase of energizing duration shows the decrease of injection quantity compared to short energizing duration. The test blending fuels have similar growth in Spray tip penetration and Spray cone angle.

• JOURNAL OF ELECTRICAL WORLD
• /
• s.268
• /
• pp.73-78
• /
• 1999

지구환경문제를 비롯하여 빌딩을 둘러싼 상황을 시시각각 변화하고 있다. 빌딩관리 시스템에 요구되는 니즈도 설비의 감시제어에서 효율적인 빌딩 운영관리에 대한 기여, 고신뢰 및 컴퓨터 네트웨크기술의 유효활용으로 변화를 보이고 있다. 미쓰비시전기의 ''MELBAS-AD''시리즈는 연 마루면적 1만$m^2$이상의 빌딩에 적합한 통합 빌딩관리 시스템으로 다음의 특징을 갖고 있으며 빌딩운영 관리와의 융합을 도모하고 있다. (1)철저한 분산처리, 2중화, 하드웨어의 고신뢰화, 독자적인 통신처리에 의한 고속화$\cdot$고신뢰화 (2)전기$\cdot$공조설비 등의 감시제어는 물론 방재$\cdot$방범$\cdot$승강기 설비의 감시제어를 통합. 또 복수 거점관리에 대응 (3)설비정보$\cdot$운전실적 정보의 일원적 관리, 설비보전 스케줄관리 지원에 의한 보전관리기능의강화 (4)미쓰비시전기 독자적인 열원 수요예측과 최적운전계획 알고리즘에 의한 에너지 관리기능의 강화 (5)화상의 디지털화, 화상처리에 의한 멀티미디어응용 감시기능의 강화 (6)브라우저를 사용한 그룸관리 및 원격에너지관리 등 인트라넷 응용기능의 강화 (7)퍼스컴이나 EWS와 전용 컨트롤러의 기기 내용연수 차이를 흡수하는 버전프리(Version free) 컨셉트 한편, 앞으로의 계획으로는 $\cdot$설비 인터페이스의 표준화와 고도화$\cdot$설비 데이터의 Seamless화 를 실시해 나갈 예정이다.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.27 no.4
• /
• pp.43-50
• /
• 1990

For constructing the steel structures of ship and automobiles etc, thin plate welding has been extensively used in recent years. However. the welding of plate produces welding deformation and residual stress which sometimes extremely harm to the safty of structure in the course of construction and operation. Therefore, in order to accurately prediet the welding deformation and residual stress, it is important to exactly analyze the distribution of temperature during welding in thin plate and take into account the moving effect of the heat source. In this paper, two dimensional unstationary heat conduction problemes of thin plate are formulated using an isoparametric finite element. After the development of the computer program, this method is applied to some specimens, and the analyzed results are compared with the experimental ones to confirm the usefulness of this method.

• Korean Journal of Clinical Pharmacy
• /
• v.24 no.2
• /
• pp.144-153
• /
• 2014

Purpose: This study aimed to investigate the correlation between the health behaviors and the aggression in Korean high school students. Methods: This was a cross-sectional study conducted with a survey of 2,676 high school students. Aggression was measured in four categories (physical aggression, verbal aggression, anger and hostility) using the Aggression Questionnaire, a modified hostility inventory by Buss and Perry. Result: Univariate analysis showed that sex, smoking, alcohol, caffeine, pain pills and gastrointestinal drugs were significantly associated with aggression scores. Boys scored higher than girls in terms of physical and verbal aggression. With respect to the habit of self-medication, students who took pain pills in the last 30 days revealed higher scores in all four aggressive constructs. From multivariate analysis, it was found that alcohol, caffeine, smoking, pain pills, sex and gastrointestinal drugs were independently associated with total aggression score in the order of importance. Alcohol and caffeine, among these factors, had strong correlation with all aggressive characteristics. Conclusion: This study identified a consistent association between the aggression of the students and health behavioral factors, but causal relationship remains to be proven.

• Journal of Ocean Engineering and Technology
• /
• v.21 no.1 s.74
• /
• pp.64-68
• /
• 2007

Recently, there has been considerable research in the field of application of Laser-Arc hybrid welding for superstructures, such as ship-structures, transport vehicles etc. However, the study on heat distribution and welding residual stress of hybrid weld by numerical simulation leaves much to be desired. Therefore, in this study, an optimized welding condition and numerical simulation for hybrid welding, using previous numerical analysis to calculate the heat source for hybrid welding, has been analyzed. For this purpose, fundamental welding phenomena of the hybrid process, using Laser and, is investigated. In order to calculate temperature and residual stress distribution in hybrid welds, a finite element heat source model is developed on the basis of experimental results and characteristics of temperature. Residual stress distribution in hybrid welds are understood from the result of simulation, and compared with the experimental values.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.1214-1223
• /
• 2009

In this study, a composite behavior of stone columns reinforced in soft ground, Sabkha, have been evaluated by a series of field measurements and numerical analysis. Field loading tests were performed to verify the effect of the composite ground reinforced by stone columns in Kayan, Saudi. The settlement measured in the field test was compared with the settlement calculated by the Priebe method and the numerical analysis using ABAQUS. It is found that the settlement estimated using the Priebe method significantly overestimated the settlement measured in the field test. In addition, it is confirmed that consideration of confinement effect exerted by surrounding stone columns in a numerical simulation is indispensable to estimate the settlement of composite ground.