• 대한기계학회논문집A
• /
• 제33권11호
• /
• pp.1274-1278
• /
• 2009

Fracture characteristics for plate and dome shapes of glass filled ceramics using shock tube were carried out. Glass filled ceramics have been considered as a promising candidate material for the dome port cover of air breathing engine. This part of the air breathing engine has an important role as separated membrane between combustion and external air, and needs the frangible characteristics that the particles of fractured glass filled ceramics should not affect the internal components of combustion. The objectives of this study are to evaluate the fracture pressures for various thicknesses and diameters of shock impact area. Also fracture phenomena of separated membrane using a shock tube compare with analytical method. The experimental apparatus consists of a driver, a driven section and a dump tank. The used material is glass filled ceramic made from Corning company. Specimens have the thickness of 3, 4.5 and 6mm. It is expected that the results obtained from this study can be used in the basic data for the dome port cover design of an air breathing engine.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.338-343
• /
• 2008

Fracture characteristics of plates and dome shapes for machinable glass ceramics using compressed shock wave. Machinable glass ceramics have been considered as a promising candidate material for the dome port cover of air breathing engine. This part of the air breathing engine has an important role separating solid and liquid fuel, and needs the frangible characteristics whereby the fracture of a part should not affect the internal components of combustion. The objective of this study are to evaluate the fracture pressure and phenomena of separated membrane using a shock tunnel. The experimental apparatus consists of driver, a driven section and a dump tank. The used material is machinable glass ceramic from Corning company. Specimens are used 3, 4.5 and 6mm thickness with plates and dome shapes. It is expected that the results obtained from this study can be used in the basic data for the dome port cover design of an air breathing engine.

• 한국분무공학회지
• /
• 제16권3호
• /
• pp.146-151
• /
• 2011

LPG(Liquified Petroleum Gas) fuel for vehicles has lots of advantages such as low emission level, cheaper fuel cost and enough infrastructure. Therefore it arouses interest as an alternative engine to reduce emission of diesel engines. Especially MPI(Multi Point Injection) type LPLi(Liquid Phase LPG injection) system could have overcome the disadvantages of mixer types such as low engine performance, decreased charging efficiency and cold starting difficulty. However ice formation on the nozzle tip and intake port due to the freezing of moisture around the components is often observed in LPLi systems. This icing phenomenon is the direct cause of unstable engine combustion, resulting in engine emissions. Therefore in this research, a spray visualization test for LPG injection was carried out to obtain the basic information of an LPLi injector, then the effects of butane and propane mixing rates on ice formation at the intake port and nozzle tip was investigated. As a result, the icing characteristics of them showed contrary results according to the mixing rates.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 추계학술대회 논문집(제1권)
• /
• pp.175-180
• /
• 2006

본 연구는 제주도 서측 해역의 현지 파랑관측 자료를 기초로 해양파의 비선형 특성을 조사한 것으로서, 실제 해역에서의 Freak wave 예보의 토대를 마련하기 위한 기초 연구이다. 관측된 파랑자료의 비선형 특성을 조사하기 위해 파형의 상하 비대칭성, 전후비대칭성, 빈도 분포의 첨예도, 파랑 스펙트럼의 대역폭 파라미터 등을 추출하고 이를 자료를 유의파고, 최대파고 등의 파랑 특성치들과의 상관관계를 분석하였다.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
• /
• pp.297-301
• /
• 2006

There are more than thirty continuously recording GPS stations (CORS) have been set up at different geological sites and distributed throughout a 140 km by 140 km area in southern Taiwan beginning since 2000, and the amount of the CORS are still under increasing in this area which is recognized the suture zone between the Philippe sea plate and Eurasia plate. From the year 2000 to the end of 2005, we analyze the daily solutions to obtain the average station velocities before and after the Chengkung earthquake which occurred near eastern Taiwan at 04:38 UTC on 10 December 2003. After considering the effects of the coseismic and postseismic displacements, the difference of the horizontal components reaches 13 mm/year of the average station velocity happened in the east side of the Central Range. To the vertical component, all of the stations are risen which located in the Coastal Range, and the largest difference approaches 20mm/year.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
• /
• pp.329-334
• /
• 2006

Rail clamps are mechanical components installed to fix the container crane to its bottoms from wind blast or slip. Rail clamps should be designed to survive the harsh wind loading condition. In this study, the jaw structure that is one part of wedge-typed rail clamp is optimized, considering strength under the severe wind loading condition. According to the classification of structural optimization, the structural optimization of a jaw belongs to shape optimization. In the conventional structural optimization methods, they have difficulties in defining complex shape design variables and preventing mesh distortions. To overcome the difficulties, the metamodel using kriging interpolation method is introduced, replacing true response by approximate one. This research presents the shape optimization of a jaw using iterative kriging interpolation models and simulated annealing algorithm. The new kriging models are iteratively constructed by refining the former kriging models. This process is continued until the convergence criteria are satisfied. The optimum results obtained by the suggested method are compared with those obtained by the DOE (design of experiments) and VT (variation technology) methods built in ANSYS WORKBENCH.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
• /
• pp.71-76
• /
• 2006

With the rapid development of spatial infrastructure in US, Europe, Japan, China and India, there is no doubt that the next generation Global Navigation Satellite System (GNSS) will improve the integrity, accuracy, reliability and availability of the position solution. GNSS is becoming an essential element of personal, commercial and public infrastructure and consequently part of our daily lives. However, the applicability of GPS in supporting a range of location-sensitive applications such as location based services in an urban environment is severely curtailed by the interference of the 3D urban settings. To characterize and gain in-depth understanding of such interferences and to be able to provide location-based optimization alternatives, a high-fidelity 3D urban model of Melbourne CBD built with ArcGIS and large scale high-resolution spatial data sets is used in this study to support a comprehensive simulation of current and future GNSS signal performance, in terms of signal continuity, availability, strength, geometry, positioning accuracy and reliability based on a number of scenarios. The design, structure and major components of the simulator are outlined. Useful time-stamped spatial patterns of the signal performance over the experimental urban area have been revealed which are valuable for supporting location based services applications, such as emergency responses, the optimization of wireless communication infrastructures and vehicle navigation services.

• 한국항해항만학회지
• /
• 제48권2호
• /
• pp.125-136
• /
• 2024

This research presents an innovative integrated ethanol solid oxide fuel cell (SOFC) system designed for applications in marine vessels. The system incorporates an exhaust gas heat recovery mechanism. The high-temperature exhaust gas produced by the SOFC is efficiently recovered through a sequential process involving a gas turbine (GT), a regenerative system, steam Rankine cycles, and a waste heat boiler (WHB). A comprehensive thermodynamic analysis of this integrated SOFC-GT-SRC-WHB system was performed. A simulation of this proposed system was conducted using Aspen Hysys V12.1, and a genetic algorithm was employed to optimize the system parameters. Thermodynamic equations based on the first and second laws of thermodynamics were utilized to assess the system's performance. Additionally, the exergy destruction within the crucial system components was examined. The system is projected to achieve an energy efficiency of 58.44% and an exergy efficiency of 29.43%. Notably, the integrated high-temperature exhaust gas recovery systems contribute significantly, generating 1129.1 kW, which accounts for 22.9% of the total power generated. Furthermore, the waste heat boiler was designed to produce 900.8 kg/h of superheated vapor at 170 ℃ and 405 kP a, serving various onboard ship purposes, such as heating fuel oil and accommodations for seafarers and equipment.

• 한국항해항만학회지
• /
• 제36권7호
• /
• pp.585-590
• /
• 2012

On the basis of the potentials for the growth of local economy and the result of investigation of the ocean space development status, an ocean resort complex was proposed at the small harbor with a parallel beach in the east coast of Korea. As the development plan needs to reclaim the noticeable amount of coastal water area together with the applied shore facilities, it is necessary to analyze their impacts. Here, it was intended to analyze the coastal environment change such as water circulation and bottom change because of the development plan. A horizontal two-dimensional numerical model was applied to represent the combined impact of wind waves and tidal currents to sediment transport in that coastal region. Based on the result of 30 days tidal current simulations considering major four tidal components of $M_2$,$S_2$,$K_1$ and $O_1$ for the upper and lower boundaries and wind field data, bottom change was discussed. Flow velocities were not changed much at outer breakwater of Yangpo harbor. Bottom was eroded by maximum 1.7m after construction but some locations such as lee side of outer breakwater and some islets near the entrance shows isolated accretions. Although it needs more field observations for bottom change in the period of construction, the numerical calculation shows that there exist small impacts near the entrance area and coastal boundaries because of the development.

• 대한교통학회지
• /
• 제26권4호
• /
• pp.275-285
• /
• 2008

"물류산업"은 장래 우리나라의 새로운 성장산업의 하나로 인식되고 있다. 그간 우리나라는 중국화물의 환적거점으로 기능을 하였으나, 최근 중국 자체항만의 성장으로 대형선단이 중국으로 이동하고 있다. 결과적으로 한국의 물류중심의 입지가 위기를 맞고 있다. 이러한 시점에서 물류혁신과 국제경쟁력 강화를 위해 새로운 전략이 필요하게 되었고, 본 연구에서는 "부가가치물류클러스터"를 새로운 전략으로 제안하고 있다. 특히 본 연구는 한국의 입지적 산업적 장점을 극대화할 수 있는 한국형 부가가치물류클러스터를 제안하고 있다. 추가적으로 한국 항만이 동북아 물류거점으로 성장할 수 있도록 한국형 부가가치물류클러스터 모형이 제안되었다. 클러스터 구성요소, 물류산업과 타 산업 간의 연관성 분석과 같은 다양한 분석과정이 한국형 부가가치물류클러스터 모형을 개발하기 위해 단계별로 시행되었다. 또한 한국형 부가가치물류클러스터 모형을 물동량 감소로 최근 위기를 맞고 있는 광양항에 적용하였다.