Muhammad Zikra

Analysis of directional wave spectra in shallow water areas using video image data

In this study, a technique for analyzing directional wave spectra in shallow water areas using video image sequences is presented. The video image was obtained and collected by a single digital video camera. The technique was based on time series of the pixel brightness on video images. The pixel can be treated as a fixed instruments through use of the rectification process. The extended maximum likelihood method and the Bayesian directional method were used to estimate directional wave spectra using two different configurations of arrays from pixel brightness on video images. The study examined video image data at HORS pier on Hasaki Beach, Japan. The results indicate that video image data could be used to estimate surface wave spectra in very shallow water areas.

Development of Eco-friendly Aquaculture Design for Lobster Cultivation in Indonesia

Lobster products are important for the economy in fishing community. Climate change will lead a threat to lobster productivity. Therefore, a solution offered is to cultivate certain lobsters, especially those with high economic value by using Aquaculture. This research aims to develop a small-scale aquaculture for the cultivation of lobsters with bamboo as primary material, which is environmentally friendly and inexpensive. The proposed design of lobster aquaculture in this research adapt lobster habitat in its nature. Therefore, it uses the artificial reef as a shelter for lobster. The main structure of the lobster cage uses bamboo and the floater use HDPE (High-density polyethylene) barrels. The result of aquaculture motion analysis using numerical model has been validated by experimental test in Flume Tank. The differences result of heave RAO (Response Amplitude Operator) motion between numerical model and experimental test is 0.05 m. The results of this validation analysis show that it is reasonable agreement.

Dynamic Modeling System for Analysis Smelter Development Plan in National Baluran Park, Situbondo

This Studies in several countries, the waste from the nickel smelter cause adverse effects on the environment, which indirectly affect the economy condition. Plan development of Nickel smelter which is directly adjacent to the national park Baluran in Situbondo quite disturbing some people. National park has a beach about 48 km long with a stretch of coral reef 5-10 meters out to sea into creating high productivity in these waters, especially various types of reef fish such as grouper. The highest numbers of catches are in district Banyuputih where the glaze was located 1734.65 tons in 2011, followed by the District Besuki with catches of 964.20 tons. In general activities in the nickel smelting are result some waste such as heavy metals such as Cu, Fe, Zn, Mn, waste heat from cooling water and wastewater canal SO2. Heavy metals and waste heatare potential adverse impact on the coral reefs, fish capture fisheries and the other marine commodities. While waste SO2 causes acid rain damage potential plant of agriculture, fisheries not only in the park but it could be damaging crops in the National Park that have an effect on the scenery, the number of visitors, and reduce operating revenues derived from the national park. We use the concept of gaming between actors to estimate the associated policy goal of this smelter. As for observing the behavior of the system over the next 10-30 years used the dynamics modeling system with 3 scenarios. Optimist scenario(there is Green smelter), excisting scenario(Condition without smelter) and pessimist scenario(there is non green smelter).

Seasonally Variation of Significant Wave Height for 25 Year Period Based on JMA/MRI-AGCM3.2 Wind Climate Data

The global ocean wave climate has long been of interest to the ocean engineering community because of the need for accurate operational wave data for applications such as vessel design, design of offshore and coastal structures or naval operations. Recently, there has been a major interest in wave climate changes as a result of global warming. Therefore, studies on predicting the effect of global warming on ocean wave climate are required. The objectives of this study are to analyze the accuracy and variability of global significant wave height hindcast for the 25 year period 1979-2003. This study describes the 25 year global significant wave height simulation derived from the Japan Meteorology Agency/Meteorology Research Institute (JMA/MRI)-AGCM3.2 wind climate data. The wind climate data were input into ocean wave model WAM with a global grid of spacing 1o in latitude by 1o in longitude. In situ wind and wave data sets from National Data Buoy Center (NDBC)-National Oceanic and Atmospheric Administration (NOAA) database were used to evaluate the hindcast accuracy. The validation showed good agreement both wind and waves data. The wave hindcast analysis show that the seasonal variability of significant wave height in the Northern Hemisphere is greater than in the Southern Hemisphere. Meanwhile, most of the equatorial regions are in calm condition all year.

Preliminary Assessment of Wave Energy Potential around Indonesia Sea

A preliminary assessment of the available wave energy around Indonesia is presented. The computations have been conducted by using the wave data collected during 35 years period from 1980 to 2014 from European Centre for Medium-Range Weather Forecasts (ECMWF). Location situated in the south of Java Sea has the most promising location for wave power potential, with the highest energy resource available in the month of January to December. The yearly mean wave power is maximum at the Java sea can reach 22 kW/m.

Anchor Strength Analysis for Mooring of a Floating Breakwater in Senoro Field, Central Sulawesi

This paper will describe complete investigations of the analysis anchor strength for mooring of a floating breakwater in Senoro Field. The terminal has berthing facilities located in a water depth about 30 meters, with the wave height of 2.7 meters that made difficult for tanker to berth properly. The requirement for berthing ships must have minimum wave heights of 0.7 meters to 1.5 meters as a requirement [1]. Considering the previously mentioned, a floating breakwater has suggested for reducing wave height. The purpose of this final project is to determine the tension mooring line and anchor pile strength to withstand all possible working loads. Response amplitude operator (RAO) of floating breakwater is used to find the structure characteristic as a response due to wave action. Based on the study, wire rope mooring was chosen due to its safety factor passed API RP 2SK standard, such as the biggest tension is 1389,68 kN on line 1 and the smallest is 1157,72 kN on line 8. Calculate anchor pile strength with three types: spun piles, spun square piles, and triangular piles. Anchor pile could be installed depending on three main factors, uplift capacity, bearing capacity and pile in compression. Based on the analysis, uplift capacity result for pile F is 1960.1 kN, while uplift load result is 1958.47 kN, and pile in compression result is 4155 kN while allowable compression result is 5532 kN. For pile G, uplift capacity result is 1960.7 kN, while uplift load result is 1958.47 kN, and pile in compression result is 4599 kN, while allowable compression result is 7189 kN.

Investigation of Risk Based Decision Making for Mobile Mooring System

This paper briefly presents the investigation of risk based decision making for mobile mooring system. This paper used bow tie analysis to analyze the risk of mobile mooring failure. Bow tie analysis consists of FTA (Fault Tree Analysis) on left part and ETA (Event Tree Analysis) on the right part. FTA is useful to determine the potential causes from critical top event until the undesired events are obtained. ETA (Event Tree Analysis) is helpful to define the possible consequence by relating an initiating event to various consequence models. The investigation consists of determining the critical hazards of mooring system failure through investigating the root causes, the consequences, and the frequency index.

DESIGN AND MODELING PILE BREAKWATER for LNG JETTY AT SENORO FIELD, CENTRAL SULAWESI

Senoro Gas Development Project is one part of a joint project between Pertamina and Medco E&P in the field of oil and gas exploration, located in Central Sulawesi, Indonesia. Senoro gas field built a jetty as berthing facility with length around 500 m from the shore. Based on the survey results showed that significant wave height is 2.7 m height at jetty area, while the requirement for vessel berthing larger than 50.000DWT is 0.7 to 1.5 m. Therefore, pile breakwater was planning to build in Senoro jetty area to protect and to reduce the wave height. From bathymetry data shows that the water depth in front of the jetty is between 20-30m. In this case, breakwater conventional or rubble mound type will not be effective for this depth. Thus, pile breakwater is one of the solutions as protection structures for protecting the jetty area from wave attack. The objective of this study is to modeling the performance of pile breakwater to reduce wave height with numerical model. For this study, analysis of the performance of the breakwater is done with numerical model of computational fluid dynamic analysis. The results indicated that pile breakwater was able to reduce the wave height for safety berthing requirement.