Ocean Engineering Commons^™

Fuzzy Statistical Refinement For The Forecasting Of Tenders For Roadway Construction, Jeng-Wen Lin, Cheng-Wu Chen, Ting-Chang Hsu

Journal of Marine Science and Technology

Due to market competition, construction companies often place low bids when tenders are invited for domestic public construction projects. Over-competition can lead to vicious price wars to win a tender, which can in turn seriously affect the quality of construction. This study aims to establish an accurate Taiwan based model for the forecasting of the tendered price for roadway construction. This model is designed to assist the public sector to determine what would be a reasonable reserve price or award price. In order to ensure accurate predictions, a data classification system is established using fuzzy set theory. For each category …

Design Of Planning Level Ship Product Model For Ship Initial Design, Sungchul Shin, Soon-Sup Lee, Jong-Kap Lee, Kyung-Ho Lee

Journal of Marine Science and Technology

This paper introduces a design of planning level ship product model (called SPPM hereinafter) based on ISO 10303 Standard for The Exchange of Product Model data (STEP). For the design of this model, the information modeling methodologies such as Integration Definition (IDEF) methods and Unified Modeling Language (UML) were reviewed, and a hybrid method was established. By using this method, ship initial design process was analyzed, and STEP-based information model and class libraries for SPPM were defined. For the data structure of this model, the shipbuilding Application Protocols (AP215, AP216 and Ship Common Model) of STEP were investigated and utilized …

Absorber Geometry Optimization For A New Wave Energy Converter, Rachel A. Durren

Masters Theses

Alternative energy technologies are on the forefront of research due to the rising costs of oil and natural gas. One relatively under development source of energy is ocean waves. In order to make the use of ocean waves economically viable, the amount of energy absorbed by wave energy converters (WEC) must be optimized. The research within presents a new conceptual design, "Aqua Fly", for a WEC with emphasis on maximizing the amount of energy absorbed. The energy absorption component of the "Aqua Fly" was isolated and a small scale 2-D study of energy absorption. First, the amount of energy in …

The Optimal Control Of A Flexible Hull Robotic Undersea Vehicle Propelled By An Oscillating Foil, David Barrett, Mark Grosenbaugh, Michael Triantafyllou

David Barrett

Determining the optimal swimming motion for a flexible hull robotic undersea vehicle propelled by an oscillating foil is an acutely complex problem involving the vehicle's body kinematics and the hydrodynamics of the surrounding water. The overall intractability of the hydrodynamics of a flexible body precludes a purely analytical solution. The immense size of the experimental variable space prevents a purely empirical one. In order to overcome both difficulties, we have developed a self-optimizing motion controller based on a genetic algorithm. This controller effectively uses evolutionary principles to exponentially optimize swimming performance.

Re-Evaluation Of Resistance Prediction For High-Speed Round Bilge Hull Forms, Jae Won

Theses and Dissertations

Predicting the resistance of a high-speed monohull has been of interest to Naval Architects for several decades. Even though considerable amount of research has been carried out in this area, there remains a degree of uncertainty in the accurate resistance prediction in the early design stage. This research thesis attempts to investigate a method for enhancing the accuracy of resistance prediction methods for high-speed round-bilge monohull form vessels for a wide range of volumetric Froude numbers (Fn). While a number of systematic series are in existence, their data are either not readily available or scattered in various internal reports and …

Numerical Modeling Of Lifting Flows In The Presence Of A Free Surface, Leonardo R. Carmona Vasquez

University of New Orleans Theses and Dissertations

This thesis work started as an attempt to create a computational tool to model hydrodynamics problems involving lifting flows. The method employed to solve the problem is potential flow theory.

Despite the fast evolution of computers and the latest developments in Navier-Stokes solvers, such as the Ranse methods; potential flow theory offers the possibility to create or use existing computational tools, which allow us modeling hydrodynamics problems in a simpler manner. Navier-Stokes solver can be very expensive from the computational point of view, and require a high level of expertise in order to achieve reliable models.

Based on the above, …

Correlation Of Shear Strength Between Longitudial And Transverse Specimens, Erasto A. Fernandez

University of New Orleans Theses and Dissertations

In this thesis, new methods for shear strength are proposed and backed up through extensive experimentation, ABAQUS models and data analysis of Titanium welds of three different alloys. The results are compared with those obtained by using the procedure outlined by AWS B4 for calculating Shear Strength in the transverse and longitudinal directions; this equation is widely used by the American Welding Society (AWS) and all those in search of more efficient designs involving welding.

It is a well-documented issue that the equation provided by AWS yields a large discrepancy between the values for shear strength of longitudinal and transverse …

Constructing The Comprehensive Subsurface Structure Of Lanyang Plain, Chih-Hao Hsu, Sao-Jeng Chao, Shuh-Gi Chern, Howard Hwang

Journal of Marine Science and Technology

This study presents an integral approach to construct a comprehensive subsurface structure of Lanyang Plain. It is well known that geophysicists and engineers use different techniques to investigate the subsurface structure, and each of these techniques has its own advantages. Therefore, in this study, the excellent results from these two fields are selected and combined to provide a comprehensive profile of the subsurface structure of Lanyang Plain. In this study, the subsurface information on nine recording stations and digital boundary lines of Lanyang Plain based on the digital geologic map published by the Central Geological Survey are utilized to create …

Slamming Induced Dynamic Response Of A Floating Structure, Mohammad Ali Lotfollahi-Yaghin1, Mehdi Rastgar, Hamid Ahmadi

Journal of Marine Science and Technology

Study of the slamming phenomenon is one of the most important branches of the floating structure dynamics. Experimental study of the floating structure dynamics can be very expensive because it requires a long wave flume and a moving model. Hence, numerical methods are considered to be very useful and efficient tools for modeling and dynamic analysis of floating structures. In the present paper, slamming induced impulsive loads are investigated firstly. Afterwards, dynamic response of a barge under the slamming excitation is studied, and the natural frequencies and mode shapes are determined, using the FE software package, ANSYS. Critical cross sections …

Age, Gender, And Muscle Strength: A Study Based On Indonesian Samples, Henny Henny, Hardianto Iridiastadi, Iftikar Zahedi Sutalaksana

Makara Journal of Technology

Age and gender have been commonly used as a main criterion in accepting a job aplicant, but it is usually not clear how these affect job performance. While a number of recent studies have been done that describe the relationships between age, gender, and participants capacity (e.g., muscle strength), the results have been inconclusive. In Indonesia, in particular, such issues have been rarely investigated, and it is still important to study the issue since the relationships between these factors are population-specific. This study aimed at describing the relationships between age and muscle strength among workers for both genders. Ninety-six male …

Fuel Saving Strategy In Spark Ignition Engine Using Fuzzy Logic Engine Torque Control, Aris Triwiyatno, Sumardi Sumardi

Makara Journal of Technology

In the case of injection gasoline engine, or better known as spark ignition engines, an effort to improve engine performance as well as to reduce fuel consumption is a fairly complex problem. Generally, engine performance improvement efforts will lead to increase in fuel consumption. However, this problem can be solved by implementing engine torque control based on intelligent regulation such as the fuzzy logic inference system. In this study, fuzzy logic engine torque regulation is used to control the throttle position entered by the driver to achieve optimal engine torque. An engine torque vs. throttle position and engine speed mapping …

Circularly Polarized Microstrip Array Antenna For Ground Segment In Quasi-Zenith Satellite System, Fitri Yuli Zulkifli, Eko Tjipto Rahardjo

Makara Journal of Technology

In satellite communication system, antenna plays an important role. Therefore, the antenna must meet some requirements, such as high gain, circular polarization, and good directivity. In this paper, a four element linear array triangular patch microstrip antenna with cross slot is designed to be used for Quasi-Zenith satellite system. A simulation study as well as experimental study was carried out. The simulation showed that the 3 dB axial ratio bandwidth of 87 MHz (2.569-2.656 GHz) is achieved while the measured results showed 96 MHz (2.556-2.652 GHz). The linear array of 4 element antenna has a gain of 13.73 dB and …

Corrosion Rate Of Carbon Steel For Flowline And Pipeline As Transmission Pipe In Natural Gas Production With Co2 Content, Andi Rustandi, Muhammad Adyutatama, Enriko Fadly, Norman Subekti

Makara Journal of Technology

The purpose of this research is to investigate the corrosion rate of carbon steel as flowline and pipeline in natural gas production with CO2 content. The influence of variety of conditions that represent the actual conditions in practice such as CO2 partial pressure and solution composition, particularly NaCl percentage were performed. Research conducted by polarization test and simulation methods using PREDICTTM software. The result of this research is used to illustrate the level of corrosion rate of typical carbon steel i.e. API 5L X-52 occurred in natural gas pipelines due to the effect of dissolved CO2. From the experiments obtained …

Optimizing Fermentation Medium To Produce Cyclosporin A Using Response Surface Methodology, Rofiq Sunaryanto

Makara Journal of Technology

Response surface methodology (RSM) is a three factorial model which illustrates the relationship between one or more independent variables. RSM can be used to optimize the fermentation medium for the production of Cyclosporin A from the isolate Tolypocladium inflatum. The optimal point of the response surface area is predicted by using a seconddegree polynomial model and applying the statistic model obtained from the central composite design (CCD). The results of optimizing the fermentation medium for Cyclopsorin using the three independent variables of glucose, casein, and KH2PO4 show that all three of the independent variables affect the production of Cyclosporin A. …

Evaluation Of Universitas Indonesia’S Recharge Pond Performance And Potential Utilization For Raw Water Source, Nyoman Suwartha, Resky Agaslian Pramadin

Makara Journal of Technology

Evaluasi Kinerja Waduk Resapan UI dan Potensi Pemanfaatannya sebagai Sumber Air Baku. Waduk resapan Universitas Indonesia (UI) telah dibangun sejak 5 tahun yang lalu. Namun kegiatan monitoring dan evaluasinya sangat minim dilakukan. Tujuan dari studi ini adalah untuk mengetahui laju resapan, dan untuk mengevaluasi kondisi kuantitas dan kualitas air waduk resapan selama musim kemarau dan penghujan. Pengukuran kedalaman muka air, intensitas curah hujan dan penguapan dilakukan untuk menentukan ketersediaan air, laju resapan, dan imbangan air waduk. Sejumlah air permukaan diambil dari waduk resapan dan sungai di tiga titik sampling untuk mengetahui kondisi kualitas air eksisting. Hasil studi menunjukkan tidak ada …

Concurrent Engineering Of Tolerance Synthesis And Process Selection For Products With Multiple Quality Characteristcs Considering Process Capability, Mohamad Imron Mustajib

Makara Journal of Technology

The existences of variances that are very difficult to be removed from manufacturing processes provide significance of tolerance to the product quality characteristics target of customer functional requirement. Furthermore, quality loss incurred due to deviation of quality characteristics of the target with a specified tolerance. This article discusses the development of concurrent engineering optimization model of tolerance design and manufacturing process selection on product with multiple quality characteristics by minimizing total costs in the system, namely total manufacturing cost and quality loss cost as functions of tolerance, also rework and scrap costs. The considered multiple quality characteristics have interrelated tolerance …

Modification Of Flow Structure Over A Van Model By Suction Flow Control To Reduce Aerodynamics Drag, Harinaldi Harinaldi, Budiarso Budiarso, Warjito Warjito, Engkos Achmad Kosasih, Rustan Tarakka, Sabar Pangihutan Simanungkalit, I Gusti Made Fredy Lay Teryanto

Makara Journal of Technology

Automobile aerodynamic studies are typically undertaken to improve safety and increase fuel efficiency as well as to find new innovation in automobile technology to deal with the problem of energy crisis and global warming. Some car companies have the objective to develop control solutions that enable to reduce the aerodynamic drag of vehicle and significant modification progress is still possible by reducing the mass, rolling friction or aerodynamic drag. Some flow control method provides the possibility to modify the flow separation to reduce the development of the swirling structures around the vehicle. In this study, a family van is modeled …

Effect Of Methanol Induction And Incubation Time On Expression Of Human Erythropoietin In Methylotropic Yeast Pichia Pastoris, Adi Santoso, Neng Herawati, Yana Rubiana

Makara Journal of Technology

Erythropoietin (EPO) is a glycoprotein hormone consists of 165 amino acids and has molecular mass of 30,400 Daltons. The large quantities of these hormone required to satisfy clinical demand are currently met by recombinant expression in mammalian cell, namely chinese hamster ovary (CHO). Pichia pastoris has become popular yeast based protein production systems to substitute mammalian expression systems. P. pastoris is capable to use methanol as sole carbon and energy source. In this study, recombinant human EPO (rhEPO) protein obtained by expressing the hEPO gene in methylotropic yeast P. pastoris, strain X33. The present work was carried out to study …

An Agri-Food Supply Chain Model To Enhance The Business Skills Of Small-Scale Farmers Using Corporate Social Responsibility, Wahyudi Sutopo, Muh. Hisjam, Yuniaristanto Yuniaristanto

Makara Journal of Technology

In general, small-scale vegetable farmers experience problems in improving the safety and quality of vegetables for supplying high-class consumers in modern retailers. Farmer Group and/or Cooperative (FGC) should be able to assist its members to meet the relevant provisions of modern retail on product specifications, delivery terms, and internal business requirements. This study proposed an agri-food supply chain (ASC) model that involves the corporate social responsibility (CSR) activities to enhance the business skills of the FGC as supplier of modern retailer. Multi-objective optimization programming is developed to determine the amount and timing of supply, level of farmers training skills, quality …

Pineapple Liquid Waste As Nata De Pina Raw Material, Agus Sutanto

Makara Journal of Technology

This research aims to study the quantity, quality, ecological and economic feasibility of nata de pina production (NP) from pineapple liquid waste (PLW). The design of the study employs complete random design (CRD) with three treatments: PLW without nutrients addition (A), PLW nutrients addition (B), and PLW stored for six months with nutrients addition (C). The nata de pina’s production factors measured were weight, thickness, fiber content, color, brightness, and residual waste. The highest weight was reached in treatment B (899 grams), followed by treatment A (616.4 grams), and C (477.8 grams). The thickness of NP of the height and …