Optimization Of Shape And Control Of Linear And Nonlinear Wave Energy Converters,
2020
Michigan Technological University
Optimization Of Shape And Control Of Linear And Nonlinear Wave Energy Converters, Jiajun Song
Dissertations, Master's Theses and Master's Reports
In this dissertation, we address the optimal control and shape optimization of Wave Energy Converters. The wave energy converters considered in this study are the single-body heaving wave energy converters, and the two-body heaving wave energy converters. Different types of wave energy converters are modeled mathematically, and different optimal controls are developed for them. The concept of shape optimization is introduced in this dissertation; the goal is to leverage nonlinear hydrodynamic forces which are dependent on the buoy shape. In this dissertation, shape optimization is carried out and its impact on energy extraction is investigated. In all the studies conducted …
Development Of Horizontal Axis Hydrokinetic Turbine Using Experimental And Numerical Approaches,
2020
Missouri University of Science and Technology
Development Of Horizontal Axis Hydrokinetic Turbine Using Experimental And Numerical Approaches, Abdulaziz Abutunis
Doctoral Dissertations
“Hydrokinetic energy conversion systems (HECSs) are emerging as viable solutions for harnessing the kinetic energy in river streams and tidal currents due to their low operating head and flexible mobility. This study is focused on the experimental and numerical aspects of developing an axial HECS for applications with low head ranges and limited operational space. In Part I, blade element momentum (BEM) and neural network (NN) models were developed and coupled to overcome the BEM’s inherent convergence issues which hinder the blade design process. The NNs were also used as a multivariate interpolation tool to estimate the blade hydrodynamic characteristics …
Fft Phase Shift Of Water Wave Analysis,
2019
Ph.D., National Taiwan Ocean University, Taiwan, R.O.C
Fft Phase Shift Of Water Wave Analysis, Chu-Kuan Lin, Shih-Yu Hsu, Jaw-Guei Lin
Journal of Marine Science and Technology–Taiwan
The fast Fourier transform (FFT) has been accepted as a tool for signal processing. This study conducted a series of numerical experiments using Matlab. By conducting FFT analysis on designated wave trains, the FFT results revealed that an extra phase shift of ��ሺ2�� ��⁄ ሻ , with N representing the number of data points for an i-th wave component, was implicitly added to the analyzed phases during the analysis. When extra phase shifts were subtracted from the analyzed phases of each component, signals could be completely reconstructed in the time domain with an acceptable difference. This study tested component and …
A New Synthesized Microalloys Steel Ods Of High Amplitude Ultrasonically Irradiation,
2019
PSTBM-BATAN, Puspiptek Serpong Area, Tangerang Selatan 15314, Indonesia
A New Synthesized Microalloys Steel Ods Of High Amplitude Ultrasonically Irradiation, Marzuki Silalahi, Hanif Abdurrahman Wicaksana, Ferhat Aziz, Syahfandi Ahda, Mohamad Riza Iskandar
Makara Journal of Technology
Micropowders of oxide-dispersion-strengthened (ODS) steel have been synthesized using the ultrasonic irradiation method with variations in amplitude. The ultrasonic irradiation process is performed for 50 h at a frequency of 20 kHz with 40%, 50%, and 60% amplitudes in toluene solution. The formation of Fe-Cr microalloys in the preparation of Fe- 15Cr-0.5Y2O3 powder was analyzed using SEM-EDS, X-ray diffraction (XRD), and TEM-EDS. The percentage of Fe- Cr phase mass fraction of ODS steel micropowder formed during ultrasonic irradiation with 40%:50%:60% amplitude was 12.2%:34.1%:22.1%, with 25.67:77.02:38.51 nm crystallite size. The crystallite size at 50% amplitude was the largest, and the diffusion …
Comprehensive Inspection On The Experimental Ferritic Stainless Steel By Means Of Transmission Electron Microscopy And Neutron Diffraction Techniques,
2019
Science and Technology of Advanced Materials, National Nuclear Energy Agency (BATAN), South Tangerang 15314, Indonesia
Comprehensive Inspection On The Experimental Ferritic Stainless Steel By Means Of Transmission Electron Microscopy And Neutron Diffraction Techniques, Parikin Parikin, Mohammad Dani, Riza Iskandar, Aziz Khan Jahja, Andon Insani, Joachim Mayer
Makara Journal of Technology
The field of physical metallurgy is one of the primary beacons that guide alloy developments for multipurpose materials such as the in-core structure materials for pressure vessel components and heat exchangers. The surface microstructure of new ferritic steel with significant local constituent materials was characterized by high resolution powder neutron diffractometer (HRPD) and transmission electron microscope (TEM), combined with the energy dispersive X-ray spectroscopy (EDX). The alloy contains73% Fe, 24% Cr, 2% Si, 0.8% Mn, and 0.1% Ni, in %wt. The charge materials were melted by the casting techniques. The neutron diffractograms obtained shows five dominant diffraction peaks at (110), …
Study On Antibacterial Of Chitosan/Hydroxyapatite Doped Magnesium Composite As A Material For Bone Graft Applications,
2019
Material and Metallurgical Engineering, Institut Teknologi Kalimantan, Balikpapan 76127, Indonesia
Study On Antibacterial Of Chitosan/Hydroxyapatite Doped Magnesium Composite As A Material For Bone Graft Applications, Andromeda Dwi Laksono, Teodoro A. Amatosa, Jr., Hilda Pebrianti Octaviana Sitorus, Wentika Putri Kusuma Asih, Sulistijono Sulistijono
Makara Journal of Technology
Hydroxyapatite (HAp) is one of the constituent minerals of bone and teeth, that has been widely used for synthesizing bone graft. Due to the limitation on properties of the hydroxyapatite, it is doping with Magnesium (HAp-Mg). The addition of Chitosan (Chi) was expected to improve the antibacterial properties of HAp-Mg. The present research aims to study the influence of Chitosan with 0, 5, 15, and 25 wt% addition on biocompatibility properties of Chi/HAp-Mg composite. HAp-Mg was synthesized using the sol-gel method; meanwhile, Chi/HAp-Mg composite was manufactured by mixing Chitosan in acetic acid, and HAp-Mg was added into the mixture. The …
Evaluation Of Primal-Dual Splitting Algorithm For Mri Reconstruction Using Spatio-Temporal Structure Tensor And L1-2 Norm,
2019
Department of Electrical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia
Evaluation Of Primal-Dual Splitting Algorithm For Mri Reconstruction Using Spatio-Temporal Structure Tensor And L1-2 Norm, Mia Rizkinia, Masahiro Okuda
Makara Journal of Technology
Magnetic resonance imaging (MRI) is an essential medical imaging technique which is widely used for medical research and diagnosis. Dynamic MRI provides the observed object visualization through time and results in a spatiotemporal signal. The image sequences often contain redundant information in both spatial and temporal domains. To utilize this characteristic, we propose a spatio-temporal reconstruction approach based on compressive sensing theory. We apply spatio-temporal structure tensor using nuclear norm, in addition to the wavelet sparsity regularization. The spatio-temporal structure tensor is a matrix that consists of gradient components of the MRI data w.r.t the spatial and temporal domains. For …
Influence Of Nh4f In Dextran Based Biopolymer Electrolytes: Conductivity And Electrical Analysis,
2019
Institute for Advanced Studies, University of Malaya, Kuala Lumpur 50603, Malaysia
Influence Of Nh4f In Dextran Based Biopolymer Electrolytes: Conductivity And Electrical Analysis, Muhamad Hafiz Hamsan, Mohd Fakhrul Zamani Kadir, Shujahadeen Bakar Aziz, Muhammad Amirul Solihin Azha, Saifful Kamaluddin Muzakir
Makara Journal of Technology
Dextran polymer host was doped with different concentrations of ammonium fluoride (NH4F) via casting technique. In this present work, dextran-NH4F film has been employed to investigate the ionic conductivity using electrochemical impedance spectroscopy from 50 to 5 MHz. The highest room temperature conductivity is achieved at (2.33 ± 0.76) × 10-3 S cm-1 with 40 wt.% NH4F. The electrolyte is found to obey Arrhenius rule at high temperature with activation energy of 0.21 eV. Dielectric analysis has been performed to obtain better understanding on the conductivity pattern. The dielectric parameters e.g. ɛreal, ɛimag, Mreal, and Mimag have been tested as …
Acute Toxicitystudy Of Choline Based Ionic Liquids Towards Danio Rerio Fish And The Aggregation Behavior Of Their Binary Mixtures,
2019
Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak 32610, Malaysia
Acute Toxicitystudy Of Choline Based Ionic Liquids Towards Danio Rerio Fish And The Aggregation Behavior Of Their Binary Mixtures, Mansoor Ul Hassan Shah, Nasruddin Nasruddin, Suzana Bt Yusup, Muhammad Moniruzzaman
Makara Journal of Technology
Marine oil spills are effectively controlled by chemical dispersants. However, the toxicity associated with it reduce its employment in marine environment. To overcome this limitation, the acute toxicity of choline based ionic liquids was evaluated as a potential low toxic variant for oil spill remediation. Further, the aggregation behavior of the individual as well as their binary mixtures was also evaluated by employing tensiometry technique. The half-lethal concentration, LC50on zebrafish (Danio rerio) of three choline based ionic liquids showed that the studied ionic liquids (ILs) fall in the range of “practically nontoxic” ( 100-1000 mg L-1).Various micellar properties showed that …
Neutron Diffraction Study Of Multiferroic 0.6nife2o4/0.4batio3 Composite,
2019
Centre for Science and Technology of Advance Materials-BATAN, Puspiptek, Serpong 15314, Indonesia
Neutron Diffraction Study Of Multiferroic 0.6nife2o4/0.4batio3 Composite, Engkir Sukirman, Yosef Sarwanto, Syahfandi Ahda, Andon Insani
Makara Journal of Technology
Neutron diffraction study on the 0.6NiFe2O4/0.4BaTiO3 multiferroic composite has been carried out. The 0.6NiFe2O4/0.4BaTiO3 multiferroic composites have been synthesized by solid reaction method. In this study, 20 g of BaTiO3 (BTO) and 20 g of NiFe2O4 (NFO) compounds were prepared from the powder raw materials of BaO3 and TiO2 for BTO, and NiO and Fe2O3 for NFO. Furthermore, both BTO and NFO were each crushed for 5 hours using High Energy Milling (HEM). Then the BTO and NFO were calcined in the furnace at 950 °C/5 hours and 900 °C/5 hours, respectively. Both NFO and BTO precursors were manually mixed …
Integration Of Inboard Propulsion In Shock Mitigating Membrane Hull Technology,
2019
Florida Institute of Technology
Integration Of Inboard Propulsion In Shock Mitigating Membrane Hull Technology, Korrey Rotkiske
Theses and Dissertations
Membrane Hull Technology is a strength based marine vessel design concept that seeks to utilize the in-plane properties of fiber reinforced composites to generate a lighter weight vessel with inherent shock mitigation benefits. MHT has been applied on several Naval crafts yet the design features of inboard propulsion systems have not been addressed. Inboard propulsion systems are a very common form of propulsion used in many types of marine vessels especially larger vessels. This thesis seeks to overcome the inboard engine mounting challenges of MHT which limits use of this technology in the marine industry. The fundamental design elements of …
Numerical Simulations Of Comprehensive Hydrodynamic Performance Of Darpa Suboff Submarine,
2019
Florida Institute of Technology
Numerical Simulations Of Comprehensive Hydrodynamic Performance Of Darpa Suboff Submarine, Kenshiro Takahashi
Theses and Dissertations
A numerical study of the DARPA SUBOFF model using computational fluid dynamics (CFD) has been presented for developing a CFD application procedure to compute the hydrodynamic performance of underwater vehicles, including submarines. Several configurations, such as bare hull, fairwater, sterns, and/or ringwing-appended hulls, were examined for the straight-ahead, steady translation and turning, and self-propelled conditions. A systematic study was conducted to ensure an adequate computational domain expansion and reasonable prism layer mesh properties for solutions independent of the parameters. The hydrodynamic forces exerted on the hull and the appendages were verified and validated in accordance with a published methodology under …
Deficiencies In The Physics Of Existing Operational Wave And Surge Models,
2019
University of North Florida, Jacksonville, FL
Deficiencies In The Physics Of Existing Operational Wave And Surge Models, D. T. Resio
Ocean Waves Workshop
No abstract provided.
A New Real-Time Ocean Observing Station On Ship Shoal On Louisiana Shelf,
2019
Wave, Coastal Studies Institute, Department of Oceanography and Coastal Sciences, College of Coast and Environment, Louisiana State University, Baton Rouge, LA
A New Real-Time Ocean Observing Station On Ship Shoal On Louisiana Shelf, Chunyan Li, Peter Luo, Brian Milan, Wei Huang
Ocean Waves Workshop
One of the major challenges that we are facing in the northern Gulf of Mexico coastal area is the need of a better and reliable offshore met-ocean real time data collection system that supports the mission of Bureau of Ocean Energy Management (BOEM) and other federal and local agencies for coastal management, protection, and restoration, especially along the Louisiana coast. This area has a suite of environmental problems that require the acquisition of real time data for immediate assessment or model-based assessment and predictions that rely on this kind of data. One such system providing this kind of data is …
Update In Us Navy Global Wave Model Forecasting,
2019
Naval Research Laboratory, Stennis Space Center, MS
Update In Us Navy Global Wave Model Forecasting, J. D. Dykes, W. E. Rogers, D. Wang
Ocean Waves Workshop
No abstract provided.
Ocean Waves Workshop 2019 Session 2 Notes,
2019
Integral Consulting Inc., Santa Cruz, CA
Ocean Waves Workshop 2019 Session 2 Notes, Kaus Raghukumar, Sam Mcwilliams
Ocean Waves Workshop
No abstract provided.
Directional Spectrum Measurements By The Spotter: A New Developed Wave Buoy,
2019
Integral Consulting Inc., Santa Cruz, CA
Directional Spectrum Measurements By The Spotter: A New Developed Wave Buoy, Kaus Raghukumar, Grace Chang, Frank Spada, Tim Jannsen
Ocean Waves Workshop
The Spotter is an accurate, low-cost, easily deployable and robust solar powered wave buoy recently developed by Sofar Technologies (formerly Spoondrift). Spotter reduces costs and complexity of surface wave and current measurements, which can be useful for academic, military, and commercial research into surface wave and wave-driven dynamics. We performed a series of validation tests and research experiments with the Spoondrift Spotter. The low-cost and compact Spotter makes it easy to deploy arrays of wave buoys which was previously not feasible (or cost prohibitive) with traditional wave buoys. A well-designed array can provide a direct measurement of the directional wave …
Innovations In Metocean Sensors,
2019
Sofar Ocean Technologies, San Francisco, CA
Innovations In Metocean Sensors, Pieter Smit, T. T. Janssen
Ocean Waves Workshop
Real-time observations are critical to understand, predict and estimate the impact of extreme weather events such as extratropical hurricanes and storms. Remote sensing, moored wave buoys and advances in predictive models have greatly advanced understanding and predictive capability of extreme ocean weather. However, due to cost and complexity of traditional moored buoys, in-situ networks are typically sparse and often close to shore and not well suited to drive predictive models over meaningful geophysical scales. Here we will discuss ongoing efforts to extend the capability of the Sofar Spotter to measure marine boundary layer dynamics. With the advancement to more portable …
Ndbc Ocean Wave Observation System Update,
2019
National Oceanic and Atmospheric Administration, National Data Buoy Center, Stennis Space Center, MS
Ndbc Ocean Wave Observation System Update, Rodney Riley, Randy Stewart, Steven Dinapoli
Ocean Waves Workshop
The U.S. National Oceanic and Atmospheric Administration’s (NOAA) National Data Buoy Center (NDBC) is modifying its ocean wave observation system due to parts obsolescence. The modified system is named Ocean Wave Linux (OWL). OWL will replace the NDBC’s older and now obsolete Digital Directional Wave Module (DDWM). Once OWL completes operational verification, the DDWM will be phased out of the NDBC’s operational weather buoy network.
Pressure Effect On An Ocean-Based Humidification-Dehumidification Desalination Process,
2019
The University of Texas Rio Grande Valley
Pressure Effect On An Ocean-Based Humidification-Dehumidification Desalination Process, Yingchen Yang
Mechanical Engineering Faculty Publications
A new humidification-dehumidification (HDH) desalination process is proposed and analyzed. Being ocean based, the process does not produce any brine. It is largely powered jointly by solar energy, wind energy, and various types of ocean energies in a nearly natural way. A vacuum pump is employed to drive the air circulation throughout the HDH process. It is the only unit that consumes electricity. The HDH process is analyzed under various conditions, including using a low pressure (as low as to 0.2 atm) for humidification and the ambient pressure for dehumidification, running the entire HDH process around a low pressure (as …
