• 한국항해항만학회지
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• 제44권6호
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• pp.488-493
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• 2020

본 연구에서는 IMO에서 권장하는 수준의 선박배출 오염물질 처리시스템을 확보하기위해 항만국 의무이행 요건 중 선박배출 폐기물 수용시설의 국내 운영실태를 파악하고 해외 선진 사례를 조사하여 III CODE를 중심으로 IMO 회원국감사내용을 분석하였다. IMO는 항만에 입항하는 선박이 배출하는 오염물질을 적절하게 처리하기 위해 항만오염물질저장시설의 설치 및 운영을 권고하고 있으며 IMO 회원국 감사 시 항만국 이행실태파악을 위해 오염물질저장시설 등록 및 운영현황을 확인하고 있다. 특히 최근 환경규제로 인해 선박에 추가로 탑재된 스크러버 등과 같은 기자재에서 배출되는 스크러버 세정수를 처리하기 위한 추가적인 시설을 요하기 때문에 각 항만별로 주요 입항선박의 선종에 따라 배출되는 폐기물을 수용할 수 있는 오염물질저장시설의 구축이 필요하다. 현재 우리나라 선박배출 폐기물은 항만으로부터 육상 폐기물처리장까지 이동시켜주는 역할밖에 수행되고 있지 않으며 항만에서 배출되는 폐기물의 양과 성상에 대해서도 항만별로 모니터링하고 있지 않고 있어 항만배출 폐기물의 특성에 따른 오염물질저장시설의 적정배치가 어려운 실정이다. 따라서 본 연구에서는 현재 유창청소업의 수거실적을 모니터링 하는 방법을 개선하여 항만별로 오염물질 배출현황 및 특성에 대해 파악할 수 있도록 하고 동시에 오염물질저장시설의 적절한 배치를 통해 IMO가 권고하고 있는 '선박에서 배출되는 오염물질의 적정처리'가 가능하여 입항선박에 원활한 서비스를 제공하도록 시스템화 한다면 향후 국제해사기구의 회원국감사 대응에 있어 유리할 것으로 판단된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1203-1208
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• 2007

In the past decades, complain about ground vibration and noise induced by pile driving has been quickly increased. Because of that, auger drilled piling methods have frequently used specially in urban area. However, the present auger drilled piling methods induce inevitable ground disturbance as well as a certain degree of vibration and noise due to the final hammering. For these reasons, a new auger drilled piling method is required to be developed. This paper introduces PDT(Pulse Discharge Technology) piling method and presents the characteristics of bearing capacity. The PDT piling method is to install in-situ piles using electric power so called Pulse. The pile installed by PDT appears to be able to develop shaft and end bearing capacity efficiently. This paper introduces PDT(Pulse Discharge Technology) piling method, which is the 512nd new construction technology. The PDT piling method is to install in-situ piles using electrical power so called Pulse power. The pulse power is physical value that indicates the energy change per unit time(dE/dt). Since the pulse power is to push ground, using the pulse power is enable a hole to be expanded as well as the ground to be improved by compaction. Therefore, The pile installed by PDT appears to be able to develop shaft and end bearing capacity efficiently. In this study, couples of pile loading tests were carried out to figure out whether or not the PDT piling method is applicable to constructions like rail road facility. As a result, it was concluded that the PDT piling technique meet the requirements for such a rail road related construction.

• 한국태양에너지학회 논문집
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• 제29권2호
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• pp.1-7
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• 2009

Use of the PV(photovoltaic) generation system is increased in such areas as remote mountain places or islands at which electrical energy is not serviced. The stand alone PV system is required the power storage products such as battery, fly wheel and super capacitor. Several lead storage batteries are connected in series to get high voltages. The life of lead storage battery is shortened when over charge or over discharge takes place. So, it is needed to control batteries not to be overcharged or be discharged deeply. Voltage of each battery was ignored in former control methods in which overall voltage was used to control charge or discharge battery. In this study, the charging and discharging voltage variations of sealed lead storage batteries with l2V/l.2A were investigated step by step experiments. The results of the test show that one should consider and specify the state of each battery to prevent overcharge or deep discharge. With the basis of the experiments, we designed a monitoring unit to monitor battery voltages simultaneously using micro-controller. The unit measures voltage of 20 batteries simultaneously and displays data on the color LCD monitor with curved line graph. It also sends data to PC using the RS232C communication port. The designed unit was adapted to stand alone PV system with 1kW capacity and lead storage batteries are connected to the PV generation system. The number of lead storage batteries was 10 in series and 12V/250Ah each. Resistive load with 3kW was used for discharging.

• 한국농공학회논문집
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• 제56권5호
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• pp.67-75
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• 2014

In this study, the large-scale hydraulic model test was performed to investigate the hydraulic characteristics for development of the non-power soil cleaning and keeping system at the dike gate. The outlet height, outflow number, outflow discharge, and outflow cycle were compared and analyzed. The non-power soil cleaning and keeping system was most effective at 11.2 mm in the outlet height. And then the mean outflow cycle was 1.09 sec, and the mean outflow discharge was $0.00164m^3/s$. The total outflow number increased gradually as the water level of a water tank increased, and the outlet height decreased. As a level of water tank decreased, the mean outflow cycle was lengthened, and the unit outflow discharge increased. This result showed this system was most effective. To remove the silty clay deposited in facilities, the methods of excavation, dredging, high pressure washing, etc have been applied to the tidal facilities such as land reclamation, a small size fishing port, and a harbor for maintenance. However, this is extremely cost-ineffective, whereas the non-power soil cleaning and keeping system will bring about an enormously positive economic effect. In addition, when the non-power soil cleaning and keeping system is applied to the dike gate of land reclamation, a thorough examination of the local tidal data and the careful system planning are required to prevent the disaster damage caused by flooding.

• 한국항해항만학회지
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• 제28권3호
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• pp.259-268
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• 2004

지난 몇 년 동안, 해안지역에서 산업의 발달과 인구증가로 인해서 육지에서 방출되는 오폐수의 정화 처리 방법이 중요한 문제점으로 지적되고 있다. 처리방법으로는, 1차 처리 또는 2차 처리된 것을 수중 방류관을 통해 해안이나 심해 또는, 그 중간지점에서 방출되는데, 오폐수가 방출되면 주변의 해수를 연행하여 플룸, 제트 또는 부양성 제트의 형태로 해수면까지 상승하면서 많이 희석된다. 본 연구는 해양환경관리 및 오폐수 처리에 관한 의사결정과정에서 중요한 해양방류관 설계를 다룬다. Cormix 모델에 조위의 변화와 계절변화에 의한 몇가지 요소를 고려하여 방류수의 궤적과 희석을 다룬다. 본 연구는 방류수의 효과석인 관리를 위한 기본 데이터와 일반배치에 매우 유용하게 활용될 것이다.

• 한국해양학회지:바다
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• 제4권2호
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• pp.93-100
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• 1999

금강 하구역의 해수면 변화에 미치는 하구언 수문 작동의 영향을 알아보기 위하여 군산 내항과 외항의 조석자료를 분석하여 비조석 해수면, 평균해수면 및 주요분조의 조화상수를 구하였다. 비조석 및 평균해수면은 하구언 수문 작동이후 내항과 외항에서 낮아졌고 특히 내항에서 급격한 비조석 해수면의 하강을 보였다. 이러한 비조석 해수면의 감소로 내항과 외항사이의 평균해수면 구배가 변화되었으며 이는 주로 하구언으로부터 담수유출량이 감소하여 발생한 것으로 해석되었다. $M_2$와 $S_2$ 분조의 진폭은 내항에서 수분작용 후 급격히 증가하였고, 위상은 다소 감소하였다. $O_1$과 $K_1$ 분조의 위상과 진폭은 변화가 미약하였다 이러한 반일주조 진폭의 큰 변화는 입사파와 하구언에서 반사된 파의 중첩에 의한 것으로 해석된다.

• 한국항해항만학회지
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• 제41권4호
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• pp.243-250
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• 2017

항만은 단순히 화물을 적재하고 하역하는 것뿐만 아니라 전 세계적 생산 네트워크 및 복잡한 공급망 내에서 중요한 역할을 하는 허브로 발전해 왔다. 항만은 지역적 수준에서 국가적 수준에 이르기까지 다양한 부가가치 생산 및 고용 창출에 기여하고 있으며, 이러한 점은 항만 및 항만 이해관계자에게 중요한 이슈가 되고 있다. 본 연구는 회귀모델을 활용하여 부가가치 및 고용수치에 대한 정보가 미비한 이탈리아 내 항만 17곳의 부가가치 및 고용효과를 분석하는 것이 목적이다. 이탈리아 항만 시스템 개선의 측면에서, 본 연구는 해당 항만들의 효과와 지역경제 내에서의 역할을 측정할 수 있는 도구를 개발하여 해당 항만의 정책 입안자들이 활용할 수 있도록 하였다. 본 연구에서는 모든 이탈리아 항만들이 지역 경제에 간접적 효과보다는 직접적 효과에 더 영향을 받는 것으로 조사되었으며, 대형 항만에서는 더 큰 사회경제적 효과가 발생하는 것으로 분석되었다.

• 동력기계공학회지
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• 제12권2호
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• pp.62-70
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• 2008

The paper made a description of the method for numerical analysis and modeling of a proportional pressure control valve by bondgraph. The valve is a three port pressure regulator valve, consists of two subsystems; a proportional solenoid and a spool assembly. A purpose of this study is to analysis the dynamic characteristics of the valve using bondgraph method and to verified results that each of parameters has an effect on modeling. It considered the effect which the presence of solenoid, flow coefficient and non-linearity of resistance causes in the valve modeling. In particular, it is analyzed the effect that the solenoid interacted with modeling results and characteristics of the nonlinear resistance through orifice on the supply and discharge side of valve. Thus this paper described method to present nonlinear characteristics by bondgraph modeling method, so that we could know easily result that each parameters has an effect on the modeling.

• 대한산업공학회지
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• 제35권1호
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• pp.58-72
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• 2009

The main activities of container terminals are to load container freights to vessels, discharge them from vessels, and store them in the storage yard. Container terminals make many operational plans to execute these functions effectively. If the plans do not consider enough the loads of related resources, they may have low actualities. This study discusses the optimal yard planning model which considers various resources, such as the storage yard, yard cranes, internal vehicles, and travel lanes, in container terminals. The model determines the groups and amounts of containers which are stored in each storage block by using the resource profile. The yard planning problem is represented to the multi-commodity minimal cost flow problem and is formulated to the linear programming model. In order to explain the application of the mathematical model, the numerical examples are presented. Additionally, the relationship between the average load ratio and the relocation ratio is discussed.

• Tribology and Lubricants
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• 제20권4호
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• pp.209-217
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• 2004

Lubrication characteristics between a cylinder block and a valve plate for high speed bent-axis type hydraulic pump play an important role in volumetric efficiency and durability of pump. In this paper, a finite element method is presented for the computation of the pressure distribution between a cylinder block and a valve plate for high speed bent-axis type hydraulic pump. Also, a Runge-Kutta method is applied to simulate the cylinder block dynamics of three-degrees of freedom motion. From the results of computation, we can draw two major conclusions. One is related to the fluid film characteristics between a cylinder block and a valve plate and the other is related to the average leakage that is determined by the pressure gradient and the clearance near the discharge port. The numerical results of cylinder block dynamics were compared with the experimental results using eddy-current type gap sensors those are fixed at a pump housing.