Land Side Research Articles

Control system for offshore wind power generation system with DFIG and VSC-based HVDC transmission

This paper proposes a fundamental and efficient control technique for introducing VSC (voltage source converter)based HVDC (high voltage direct current) transmission into a large-scale offshore wind power generation system with DFIGs (doubly-fed induction generators). The electric power from the offshore wind turbine DFIG is considerably fluctuating and unstable, and needs to be transmitted from offshore to the on-land major AC system generally accompanied with long distance cable transmission. From these points of view, VSC-based HVDC transmission is considered to be an efficient choice. In this paper, control systems for the AC/DC converter at the offshore side and the DC/AC inverter at the land side are proposed and presented in details. These controls aim at mitigating the impact of wind power fluctuation on the on-land AC system, while securing the stable operation of the HVDC circuit. Furthermore, by proper control applied to the converter, voltage and frequency of the offshore AC system at the wind power plant side is stabilized so as to facilitate the stable operation of DFIGs, which is modeled by a self-excitation type with HVDC link circuit in this study. Digital simulation studies were conducted and the results have verified the effectiveness of the proposed systems.

Experimental Study on Corrosion Characteristics of CO2 Pipeline for Offshore Transport and Geological Storage

Among the technologies, CCS (Carbon dioxide capture and storage) technology is assumed and arising as crucial technology for reducing anthropogenic carbon dioxide and bridging to hydrogen economy. CCS technology includes carbon dioxide capture on the large point source, transport of captured carbon dioxide stream and storage of carbon into safe geological formations. Among the CCS processes, capture side is developing with many demonstration projects, focusing on the efficiency improvement of wet and dry absorbents, material improvement for membrane, construction cost down, etc. But in transport side, the technology is in the initial stage. In Korea, site surveys are mainly focused and operated on the offshore saline aquifers in the east sea of Korea and rather few surveys are processed in the on land side. For the offshore carbon dioxide geological storage, there are two options for transportation, using pipeline or ship. To utilize the offshore pipeline it is possible to use high chrome steel alloy to response to seawater corrosion, though the cost for construction might take huge budget for installation mainly cause of material cost. Otherwise, we considered it might be possible to apply the anti-corrosion coating outside of the carbon steel pipeline to mitigate seawater corrosion and to reduce the cost, so to secure steady and robust operation of offshore carbon dioxide transportation with little concern of corrosion issue. In this study, we investigated the possibility of using carbon steel pipeline with internal phosphate coating and external thermal spray coating as candidate for the offshore carbon dioxide transportation pipeline material. The base material for this study is carbon steel. The pipe internal corrosion test was conducted with fluids of CO2 mixture with additives of water and SO2 gas, and the external corrosion was carried out with 3.5%w NaCl solution. In the case of internal corrosion, all the specimens resulted in corroded surface with rust covered when SO2 was injected over 175 ppmv. In the case of external corrosion, zinc thermal spray with epoxy coating showed that more epoxy sealer is remained than aluminum thermal spray coating. The test result will be used to figure out economically efficient and safe candidate pipeline material.

Land-Sea Interactions in Punta China (Baja California, México): Addressing Anthropic and Natural Disturbances in a Retrospective Context

In extensive SCUBA-diving surveys of kelp forests along 350 km of the Baja California peninsula coastline from the US-Mexico borderline to Sacramento Reef, benthic species richness has been satisfactorily explained by environmental structural features such as bottom rugosity. However, values at Punta China embayment (PCE) departed significantly from the model whereas the adja- cent Santo Tomas cove (STC) did not. In addition, in August 20, 2011, visibility was under 1 m at PCE and over 10 m at STC; these conditions presumably reflect the influence of the limestone ex- traction industry located on land. In order to investigate the case allowing for temporal compari- sons, we set a regional research scenario similar to a 1993 pioneer study, comprising PCE and two contrasting sites (STC to the North, and San Jose embayment, SJE, to the South). Land and sea side were addressed separately, and a 1950-2012 time-span period was set in order to perform the analysis of retrospective data. Our results suggest that the current scenario results from the com- bined influence of a local, anthropic and chronic land-based disturbance represented by the pro- gressive expansion of limestone extraction industry, and the episodic influence of a natural, large scale and acute disturbance represented by the 1982-83 and 1997-98 El Nino events. The influ- ence of both driving forces, however, is not necessarily equally distributed in space, yielding a re- gional mosaic of natural and social conditions. Our results confirm and expand previous know- ledge in the area, and may contribute to future basic and applied research. * Corresponding author.

ECONOMIES OF SCALE AND SCOPE OF AIRPORTS – A CRITICAL SURVEY

The question whether airports are natural monopolies has increasingly become an issue in studies on regulation, deregulation and privatization of airports. In particular it was questioned whether airports have market power at all and if this is due to economies of scale and scope. This paper provides an overview of studies on economies of scale and scope. It critically evaluates the method of data gathering during the studies and the resulting information uncovers some drawbacks of the studies and the data gathering process. It reaches the conclusion that the most studies on economies of scale are problematic in regard to the definition of “output”, the treatment of capital and the exclusion of land side activities. Economies of scope have only been researched in the most recent studies. The study illustrates that the non-aviation business should be considered in more detail.

Scaling Characteristics of Developing Sea Breezes Simulated in a Water Tank

Sea-breeze circulations in a stably stratified environment have been simulated in a water tank. The floor of the tank was divided into two halves representing land and sea; the land side was heated from the bottom of the tank, and the sea side was insulated by an underlying sponge slab. The temperature profiles over both land and sea sides, the land–sea temperature difference, and the horizontal temperature distributions were measured. Particle tracking velocimetry was applied to obtain the two-dimensional velocity field orthogonal to the coastline. It was shown that the overall flow consists of a closed circulation caused by the horizontal temperature difference between land and sea, and a strong updraft occurring at the sea-breeze front. The dimensionless governing parameters are calculated from the measurements and used to characterize the developing sea breezes. The analysis confirms the scaling laws for sea-breeze velocity and depth. The results indicate that the scaling characteristics of the sea-breeze translation speed during the developing period are different to those during the following maintaining period. A criterion for the onset of the sea breeze is proposed based on these results.

Water and suspended sediment division at a stratified tidal junction

Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper presents observations of water, salt and sediment transports in three channels that connect at a stratified tidal junction. Flow variation in one channel was found to lag behind flow variation in a connected channel by more than 1 h, which is largely attributed to channel length differences from the junction to the sea. The water columns in the three channels were periodically stratified during spring tide, whereas the salinity structure represented a salt wedge during neap tide. Salinity differences between the three channels were substantial. The channels contain water bodies of different salinity and act largely independently. Flow velocities in the upper and lower layers differed substantially. Flow in the lower layer was generally in the direction of acceleration produced by the baroclinic pressure gradient. Interestingly, baroclinic pressure gradients were sometimes directed landward, indicating the presence of saltier water at the land side of the estuary. In sharp channel bends close to the junction, secondary flow was strongest at the highest axial flow velocity during spring tide. In one channel bend, these circulations steered the suspended sediment toward the inner bend, which affected the suspended sediment division.

Internal sedimentary architecture and coastal dynamics as revealed by ground penetrating radar, Kachchh coast, western India

The coastline constitutes a very sensitive geomorphic domain which is constantly subjected to dynamic coastal processes and stores vital information regarding past sea level fluctuations. A ground-penetrating radar (GPR) survey was carried out along the northern coast of the Gulf of Kachchh which is one of the largest macrotidal inlets of the Arabian Sea, Western India. Our studies have delineated several radar surfaces and radar facies which reflect the internal architecture and sediment body geometry, which can be related to the processes acting along this coastline. Various radar facies, namely, beach ridge (Br), washover (Wo), coastal dune (Cd), swale (Sw), berm plain (Bp), and sandsheet facies (Ss) have been identified. The GPR studies successfully documented the subsurface presence of ancient beach ridge system towards the sea, and the coastal dunes towards the land side. The results are suggestive of signatures of changes in sea level and the coastline being prone to high energy events in the recent past. The GPR has been found to be an important non-invasive geophysical tool in the study of past coastal dynamics.

Enhancing social capital for sustainable coastal development: Is satoumi the answer?

Social capital constitutes the cultural component of modern societies. Building social capital has typically been seen as a task for ‘second generation’ economic reform, but unlike economic policies and institutions, social capital is not created or shaped by public policy but is inherited throughout local communities successive generations. Enhancing social capital therefore is about promoting local knowledge deeply rooted into local communities' practices on land and at sea. In Japan, the culturally specific interaction of humans with nature has led to the emergence of specific socio-ecosystems called ‘satoyama’ on the land side and ‘satoumi’ on the coast and sea side. Here, characteristics of related local knowledge include information about consumed products like wild edible plants or seaweeds, and learning by doing practices like traditional rice cultivation or sea ranching. This knowledge has been developed over centuries and has been handed down from generation to generation. There are actually other types of satoyama and satoumi which have been flourishing around the world though the latter (satoumi) probably has no equivalent in other countries' coastal areas because of the unique Japanese fishing rights system. First largely ignored as a social capital, satoumi has emerged as a new concept only a few years ago. In the frame of the recently adopted national ocean policy such a social capital, like it may be found in other countries, should not be ignored when addressing integrated coastal zone management processes and tools for the sake of sustainable coastal development in Japan and elsewhere in the world.

제내 비탈끝 배수공을 이용한 제방의 침투조절에 관한 연구

하천 제방은 홍수 시 유수를 원활하게 소통시키고 제내지를 보호하기 위해 하천을 따라 축조한 시설이다. 하지만 이러한 제방도 침투로 인해 제내지측 사면에 포화표면이 지속적으로 발생하게 되면, 제방은 파괴될 수 있다. 제체 침투에 의해 발생되는 침윤선은 적절한 배수 체계를 이용하여 강하될 수 있다. 본 연구의 목적은 제내지 비탈 끝에 설치되는 배수공을 통한 침투조절의 효과를 제시하고, 각기 다른 형상을 하고 있는 미국의 공병단과 일본의 국토개발기술연구센터에서 제시한 배수공의 효과를 비교, 검토하는데 있다. 이를 위해 배수공의 포함 여부에 따른 제방 침투에 관한 모형실험을 수행하였다. 축조된 제방 모형의 규격은 둑마루폭 0.5m, 하부폭 2.6m, 사면경사 1 : 2, 제방 높이 0.55m이고, 제외지측 수위는 0.5m이다. 미 공병단의 배수공은 삼각형이고 일본의 국토개발기술연구센터의 배수공은 사각형이며, 각각의 배수공 폭은 0.4m로 설치하였다. 배수공을 포함하지 않은 제방 모형에서는 침투에 의해 제내지측 사면에 포화표면이 발생하였으나, 미 공병단과 일본의 국토개발기술연구센터에서 제시한 배수공을 포함한 제방에서는 모두 포화표면이 발생하지 않았다. 이러한 모형실험의 결과는 SEEP/W를 통한 수치모의 모형의 보정과 검증에 활용되었다. 그리고 배수공의 폭을 5 cm씩 줄여가며 수치모의를 수행해 본 결과, 일본의 국토개발기술연구센터식 배수공이 미국의 공병단식 배수공에 비해 다소 안정한 것으로 분석되었다. 또한, 일본의 국토개발기술연구센터식 배수공은 시공이 쉬운 장점이 있다. 본 연구의 결과는 향후 배수공을 이용한 제방의 침투조절 계획에 활용될 수 있을 것으로 전망된다. The levee is the facility which is constructed along with river for the protection of landside and for passage of water when there is a flood. When the seepage is exposed to the atmosphere on the landside surface of levee, it may eventually lead to levee failure. The seepage water may be removed from the landside surface by a properly designed drainage system. The purpose of the study is to show seepage control effect of a pervious toe drain, and to compare two drainage methods of a pervious toe drain. One is the pervious toe drain suggested by U.S. Army Corps of Engineers (USACE) and the other is that suggested by Japan Institute of Construction Engineering (JICE). The levee model constructed has the following dimension: the base width is 2.6 m; the crest width is 0.4 m; the side slope 1 : 2. The water depth in the riverside is 0.5 m. The shape of the toe drain by USACE is triangular. The shape of the toe drain by JICE is rectangular. They were installed with the base length of 0.4 m. The levee model without the toe drain showed saturation surface on the land side in the experiment but not with the toe drain. The experiment results was applied to a numerical analysis model using SEEP/W to calibrate and verify. The numerical analysis results for 35 cm and 30 cm drain width showed that the drain by JICE is a little bit safer than the drain by USACE. It is also easier to construct the toe drain by JICE. The results in the study would be applied to plan the seepage control for a levee with pervious toe drain.

Kajian Keamanan Bandara Sultan Mahmud Badaruddin II-Palembang

An airport security from unlawful recruitment must start from the(acceptance) airport security personnel with the support of airport security equipment, as well as its security systems and procedures. Supervision of an airport security needs to be done since the area is not a public area where everyone is free to exit and enter without having to show identity card (Airport PAS), as well as passenger ticket. Furthermore, more stringent security controls imposed on the land side area airports (land side) up into the air side.

Evaluasi Fasilitas Sisi Darat Bandara Sultan Thaha Jambi Sebagai Bandar Udara Internasional

Sultan Taha Syarifuddin Airport is an airport located in the province of Jambi. This airport began in April 2007 is managed by PT. Angkasa Pura II, which was previously managed by the Department of Transportation Jambi Province. PT.Angkasa Pura II (Persero) as the steering Airport, Jambi Sultan Taha Sultan Taha Airport development plan to be an international airport on 2012. Currently there are 5 air transport company which is every day in flight Sultan Taha Airport. Based on Forecast result (forecasting), the movement of aircraft on 2011 at 7.24%, 5.73% in 2012 and in 2013 5.429%. The number of passengers in 2011 rose 15.14% in 2012 rose 7.64% in 2013 rose 7.09%. While number of the cargo on 2011 rose 3%, 3% in 2012 and 2013, 3%. The analysis result of land side facilities at Sultan Taha Airport Jambi at departure are for the development of 274.31 m2 space. Need development of space for the arrivalare of 248 m2. Area of 134 m2 is adequate toilet but the toilet really badly because there are only 4 pieces of toilets currently available. Baggage claim area was not sufficient anymore the addition of 37.88 m2. Hall of arrival to the development of 311.51 m2. While fhe obstacles / problems related to building new terminal facilities of international standard can be implemented that is not related assets owned by DGCA is not handed over / transferred to PT.Angkasa Pura II (Persero) and there is still the official residence owned by DGCA.

English

This paper developed a risk-based modelling approach to enhance safety in the region around the airport that could be affected by an aircraft accident during the landing phase. Special attention was given to the following aspects: A strategic approach to improve airport safety, which includes the use of failure and hazard analysis techniques and fast time simulation modelling, and safety of land side operations. This analytical approach determined the area affected by different probabilities of accident occurrence (frequency of occurrence of a defined hazard). The mathematical model presented in this paper takes into consideration items determined to be important to understanding the risk of an aircraft crash into certain facility. The probabilistic approach to risk assessment was based on magnitude function that would be determined with reference to a number of aircraft operations/flights; crash probabilities; aircraft characteristics; facility characteristics; crash impact and facility damage. The final product of this research was a quantitative tool that can be utilized both in airport planning and in Safety Management System (SMS) implementation. Key words: Safety management system, aircraft landing, risk assessment modelling.

시공 중 수중터널 벌크헤드에 작용하는 충격쇄파압 - 수치해석 및 수리모형실험 -

충격쇄파압은 권파성 파랑이 구조물 전면에 갑자기 충돌할 때 발생하며 접촉면에서 공기포켓의 생성여부에 따라 충격쇄파압의 작용특성이 달라진다. 수괴의 직접적인 충돌에 따른 Wagner형은 접촉면에서 단일 압력 첨두치를 보이는 반면, Bagnold형은 공기포켓의 진동에 의하여 비접촉면에서도 압력의 첨두치를 보이는 특성이 있다. 본 연구에서는 시공 중의 수중터널 벌크헤드의 배면(육측면)에 발생하는 충격쇄파압을 고찰하였다. Navier-Stokes 방정식을 직접 푸는 수치해석을 적용하여 벌크헤드 인근에 발생하는 쇄파를 모의한 결과, 벌크헤드의 배면에서 강한 Bagnold형 충격쇄파압이 발생함을 확인하였다. 본 충격쇄파압의 존재는 동일 조건에 대하여 수행한 수리모형실험에 의해서도 확인되었으며, 실험결과와 수치해석결과가 대체적으로 유사한 성향을 보임을 확인하였다. The breaking wave pressure occurs when a plunging breaker instantaneously impinges on structural surface, and appears differently depending on whether or not to form air pockets at the instant of contact. The Wagner type normally forms a single pressure peak at the contact spot due to the direct collision of water volume to the structure whereas in the Bagnold type the time lagged oscillation of the air pocket causes pressure peaks even at areas away from the spot. In the present study, the Bagnold's impact pressure is numerically and experimentally investigated for the bulkhead of an underwater tunnel under construction which is subjected to nearby breaking waves. A numerical solver of Navier-Stokes equations was applied to reproduce the breaking waves near a bulkhead, and the results showed the Bagnold's impact pressure occurring on the back (land side) face of the bulkhead. The existence of the impact pressure was also verified by a hydraulic model testing, and it was found that the experimental results well conformed to their numerical counterparts.

외해 가두리 양식장용 먹이공급시스템

The depleting fishes resource and water pollution in coast has a decisive effect on the fish farm and fisheries. For solving these problems the fish farms are moving to the offshore. The fish farms in offshore have to design the strong mechanism as compared with cost`s fish farm, and operate by the remote feeding system and monitoring system for safety and management.. This paper describes a remote feeding system for fish farms in offshore. The amount of feed is depending on temperature and fish weight. The fish farm temperature is changed extremely in offshore than on land side. This paper described that the feed amount is calculated automatically according to temperature and fish weight, and the remote feed system. The performance of remote feed system is tested with model.

Kemampuan Bandara Sultan Hasanuddin Makassar Menghadapi Pengoperasian Pesawat Udara Super Jumbo A-380

Aviation technologi develops increasingly sophisticated marked by producing of super jumbo aircraft Airbus A-380. This aircraft has four engines made by Rolls-Trent Royce-90 is capable to provide 36.280 Kg of thrust or four turbo-fan engine Alliance HP 7200 with 37 003 Kg of frust with passenger capacity up to 850 passengers. In the world, aviation business world today around 15 airlines have ordered the aircraft (total 154 order), such as Emirates, Lufthansa, Qantas, Singapore Airlines, dan Malaysia Airlines.In order to anticipate the development of aviation technologi, Idonesian government have to prepare airport in Indonesia that could be landed by super jumbo aircraft Airbus A-380. For the case, it needs to conduct the study on the readiness of Sultan Hasanuddin Airport in Makasar for the operation Of the super jumbo aircraft Airbus A-380. The evaluation of readiness for area, air side and land side facilities including the support facilities that might be developed to accommodate the aircraft Airbus A-380.

Spontaneous Discrimination of Polycyclic Aromatic Hydrocarbon (PAH) Enantiomers on a Metal Surface

Surface control: Vacuum deposition of a planarized PAH (C60H30) on a Pt(111) surface induces chirality caused by the different landing side of the molecule, as shown by in situ STM images. The surface determines the landing side of individual molecules, which present different structural geometries that are shifted by about 35° (see figure). Large-scale calculations explain the atomistic mechanism of the process.

Hydrodynamic factors affecting the persistence of the Exxon Valdez oil in a shallow bedrock beach

We report a field study and numerical modeling of multicomponent flow in a tidal gravel beach in Knight Island, Prince William Sound, Alaska, where oil from the 1989 Exxon Valdez oil spill persisted. Field measurements of water table, salinity, and tracer (lithium) concentration were obtained for around a week during the summer of 2008. The numerical model MARUN was used to simulate the field observations. On the basis of field experiments and numerical simulations, the beach was identified to have a two‐layered hydraulic structure: a high‐permeability surface layer underlain by a low‐permeability lower layer. The hydraulic conductivity was found to be 5 × 10−2 m s−1 for the surface layer and 7 × 10−6 m s−1 for the lower layer. The simulations reproduced the observed water table, salinity, and lithium concentrations accurately. The small flow entering the beach from the land side resulted in a beach water table dropping below the interface of the two layers. This seems to be the major reason for the presence of oil in the lower layer. The exchange flow between the beach and the sea due to tidal influence was ∼2.12 m3 d−1 m−1. The patterns of inflow and outflow rates showed that the maximum seawater‐groundwater exchange occurred in the middle to high intertidal zone, which explains the persistence of oil in the lower intertidal zone. To explore bioremediation of the beach with nutrient amendment, a numerical simulation of nutrient application on the beach surface was conducted, where the applied nutrient concentration was 5,000 mg L−1. The results showed that the nutrient concentration remaining in oiled areas after a week was larger than 50 mg L−1, which is larger than that needed for maximum microbial growth (2–10 mg L−1). This implies that the bioremediation via nutrient application on the beach surface could be adopted if nutrients were the only limiting factor.

Evaluasi Pelayanan Penumpang Bandara Mutiara Palu

The airport is an for aviation services, where in variety of good facilities for service to the aircraft as well as for passanger service. Air transport passenger service at airport from time to time require upgrading the performance of services, both from land and air side services. Which became problems as Palu Mutiara airport if the airport is already providing service accordance with the standard of service (level of sercvice). and how the airport in activities of air transport services with limited passenger terminal condition, especially during busy (peak season).

Kajian Lalu Lintas Angkutan Udara Penumpang dan Kargo di Bandara Internasional Soekarno-Hatta

Forecasting is needed in the planning and designing process structure and infrastructure of airport such as air side facilities, supporting facilities. land side facilities, and even the road network from and to the airport. Airport development is on air traffic forecasting. By using a quantitative model with exponential smoothing and the regression model (causal) will be obtained traffic forecats of air transport passengers and cargo at Soekarno-Hatta Internasional Airport. The results of the study showed that growth prediction of air transport in 2010 for 8.75% and the growth of air cargo decreased by -2.17%

A Grey-Based Taguchi Approach for Characterization of Erosive Wear Phenomenon of Glass–Polyester Fly Ash Filled Composites

Fly ash is a solid waste generated in huge quantities from coal fired thermal power stations during the combustion of coal. In India, less than half of this is used as a raw material for concrete manufacturing and construction; the remaining is directly dumped on land side as land fill or simply piled up. Only a small fraction of it is used in development of high valued product. Due to environmental regulations, new ways of utilizing fly ash are being explored in order to safeguard the environment and provide useful ways for its utilization and disposal. With its richness in various metal oxides, it has tremendous potential to be utilized as a filler material in polymer composites. These days glass reinforced polyester composites find widespread application in erosive environment due to several advantages like high wear resistance, strength-to-weight ratio, and low cost. The cost of the composites can be further brought down using cheaper filler materials. To this end, this work uses fly ash in composite making and thereby suggests a new way of better utility of this industrial waste. It includes the processing, characterization and study of the erosion behavior of a class of such fly ash filled polyester-glass fiber composites. The engineering application of composites demands that it should have high wear resistance, low density and high tensile strength. In order to assess the behavior of composites satisfying multiple performance measures, a grey-based Taguchi approach has been adopted. After thorough analysis of factors, optimal factor settings have been suggested to improve multiple responses viz., erosive wear rate, density, flexural strength and tensile strength. This technique eliminates the need for repeated experiments; thus saves time and material. The systematic experimentation leads to determination of significant process parameters and material variables that predominantly influence the multiple responses.