Marine Systems and Technologies

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作者: Danang Cahyagi, Raja Oloan Saut Gurning
摘要: Fishermen poverty is multi-dimensional problems. Since the fishermen income always under regional minimum wage. Inversely with position of Indonesia that become the world third largest in fishing production. At the same time, Indonesian fisheries are under threat due to degradation of marine ecosystem and overfishing. Therefore, enhancing the massive production is not a solution to solve all problems. The main purpose of this paper is collecting the view of researchers related to the causes and solutions as poverty alleviation. The poverty alleviations can be started with improvement in fish catching and processing, transparent and environmental friendly, increasing fishermen’s ability, and good management of assets.
作者: Zainul Hidayah, Daniel M. Rosyid, Haryo Dwito Armono
摘要: Coastal area has a strategic value for the development of national economy and improving people's welfare. However, coastal area is also extremely vulnerable to environmental damage and destruction. Therefore, the need of sustainable management with regard to the dimension of ecological, economic, social and institutional is important. This research is aimed to overview the current condition of coastal area in the Madura strait and to formulate coastal management strategies in term of sustainable development. Multi Dimensional Scaling (MDS) method was used in this research. Five dimensions (ecology, economy, social, technology and institution) were measured. The results showed that in general, coastal management of Madura Strait was less to moderately sustainable. It means that coastal management of the area has given enough contribution for the community; however the condition of the environment should be supervised closely to provide continuous benefit for future economics of the region.
作者: Mila Tartiarini, Udisubakti Ciptomulyono
摘要: Waste water result from operating activities of Grati Combined Cycled Power Plant (CCPP) is significant amount and has potentially to be reutilized. A recycling unit as the pilot project has been applied in Grati CCPP PT Indonesia Power UP Perak Grati for capacity 4 tons/hour of service water product. Development plant of Grati CCPP up to year 2018 will produce more amounts of waste water, and potentially increase the pollution load in the unit area.Considering the use of alternative development for unit recycled waste water effluent from the Waste Water Treatment Plant (WWTP) has implications to the environmental and cost aspects, therefore a proper assessment to decide the alternative is needed. Proposed method of Life Cycle Assessment (LCA) is to measure the impact to the environment. And the Cost Benefit Analysis (CBA) is to measure the economic criteria. To integrate the results of the two methods, it is used and calculated by using Hierarcy Analytical Process (AHP).The result of the study about the environmental impact and economic analysis, the development of the recycling unit is required to process all waste water produced by power plants. Focus group by experts in power plant operation using AHP is based on the results of SimaPro 7.0 and CBA. The most beneficial result is with a single score of 0.2314 Pt / 1 ton of water service, the payback period of 2.5 years, 37.5% IRR and NPV US$ 88,577.23 and the MMF-RO unit for total capacity of 14 tons/hour has become the most alternative of development.
作者: Sapto P. Kertorahardjo, Harold Vincent, Putranta H. Duta
摘要: Most of the artificial reefs that have been developed in the world are the concrete structure. Regarding economical and practical consideration of artificial reefs, Indonesian government - Ministry of Marine Affairs and Fisheries - has proposed a new material to make an artificial habitats including artificial reefs made from polypropylene plastics (PP). However, diminishing approximately 80% of the weight structure compare to concrete structure has created new challenges to maintain the underwater structure with similar function. Moreover, the use of less weight material for artificial reefs structure will have impact on the structure responses.The structure responses due to sea bottom current and tidal stream velocity have been evaluated at several conditions. Dynamic pressure calculation was applied gradually as external load from a simple part to whole complex structure. Stresses and strains occur at some nodes as the structure critical area, within the same time frame, displacement of its elements describe physical characteristic response. Boundary conditions was encastred the sinker- bottom structure (U1 = U2 = U3 = UR1 = UR2 = UR3 = 0). In conclusion, for input of sea bottom current velocity u = 0.2 m/s the results for maximum stress are below the material’s yield stress hence its elasticity is relatively adequate to prevent permanent deformation. The result also showed some critical part of the structure that has high value on stress should be consider as the current velocity increase. Moreover increasing input and frontal area will significantly affect the drag force which will add load on the structure.
作者: Aries Sulisetyono, Lalu Muhammad Jaelani, Eddy Setyo
摘要: Poteran is a small island as part of Sumenep Madura Indonesia where it has the natural resorces to be developed into a sustainable small island. Increasing the local economy based on fisheries sector has a high potential to be developed. In small fisheries industry, the electrical energy is necessary needed, so that the marine power plant technology is relevant to be employed in this island. This paper describe the concept design of current power technology which is suitable to be implemented in the island consider to the enviromental sea condition. Potential current energy captured is identified based on the measurement of current speed for the short period of time at the coastal area of island. Futhermore, the turbine design of current power technology is introduced as well as the design of floating platform.
作者: Sony Junianto, Rudi Walujo Prastianto, Mukhtasor
摘要: Ocean renewable energy research has been progressing well. Supporting structures are needed to convert energy from the sea. This paper discusses the response of the floating structure for ocean renewable energy conversion system by providing a simple design of floating structure. Due to its function, the system is limited for the pitching motion. By using the Lagrange formula, the equation of motion of the system can be obtained. In the analysis, there are three variations of wave period to determine the response of floating structure motion. The result shows the trend where the larger wave periods induce larger intersection angle (larger response) of the structure. The floating structure configuration for the ocean energy converter should be determined in such a way that have the most stable motion-response in any condition. The stability of floating structure will affect the current forces in the rotated turbine. It needs a specific design to hold the stability of floating structure.
作者: Murdjito, Maria Putri Rosari, Eko Budi Djatmiko
摘要: Evaluation is carried out on the operability of a 87,900 ton Sevan Stabilized Platform (SSP) functioned as an FPSO in the hypothetical operational site of Masela Block. This is to observe the critical conditions when side-by-side (SBS) offloading is performed between the SSP and a 35,000 DWT shuttle tanker. The first stage of analysis conducted on the moored SSP as a single floating body indicates the capability to withstand a 100-year wave, designated by the significant height of 8.0 m. Largest motions are experienced when SSP contains 75% load capacity, resulting in the mooring tension range from 2,000 kN up to 7,000 kN, portraying ample safety factors of 2.0 up to 3.0. The second stage of analysis is conducted for execution of SBS offloading from SSP to shuttle tanker, positioned in a 3.3 m distance. Observation is made when SSP is loaded with 100%, 83%, and 75% capacities correlated to the shuttle tanker loading of 10%, 60%, and 90% capacities. This reveals critical conditions arise when the wave exceeds 2.0 m in height, or the operability level of some 88.5%. Safer operation and higher operability level could be achieved by increasing the distance of SSP and shuttle tanker.
作者: Fahmy Ardhiansyah, Aries Sulisetyono, Wasis Dwi Aryawan
摘要: This paper presents the heading analysis study of weathervaning turret moored unit. Design wave heading is to be in accordance with the operational conditions for the sea states contributing the most to the long term value of the dominant load effect. From the heading analysis over each of the sea states contained in the time-series, the mean heading of the floating structure can be obtained.The objective of this study is to assess heading analysis outcome as function of heading probability occurrences of weathervaning turret moored floating units and to identify dominance environment load component act to the system.In order to achieve the above objective, the numerical model has been developed. The model is generate a vessel model by describing the capability to weathervane. It will be performed with MOSES software packages and numerical tools, both in the time-domain and frequency-domain.The heading analysis results indicates that the most affected external forces is dedicated by wind, it is seen the relative heading between wind and vessel heading is quite small (<10degree) with large occurrence probability (up to 60%). The proposed double static approach method to solve heading analysis has been investigated by comparing to former approach which is found a good result agreement between them.
作者: Mukhtasor, Sony Junianto, Rudi Walujo Prastianto
摘要: Offshore engineering rules have been important part in supporting industrial development of tidal current energy conversion (TCEC) systems. The rules have been considered as guidelines for design of fixed type of TCEC systems, particularly those provided by European Marine Energy Centre (EMEC). However, for floating type of TCEC system, this is not the case. In fact, floating systems have a potential application for particular area of interests, for example in the area with strong currents at the seawater surface or in that with minimal infrastructure for installation support. In future, floating TCEC systems might be installed at the offshore area, even though the current application is commonly at the nearshore. Therefore, it may be beneficial to adopt relevant aspects of the offshore engineering rules for the floating structure design to support TCEC systems. This paper identifies elemental rules which may be suitable for application in the design of this type of floating structure. It includes choice of configurations, dynamic response analysis, material selection, mooring-water depth analyses and removal. This work is an important part of the whole big effort in supporting the development of ocean renewable energy industries.