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Electromechanics Of An Ocean Current Turbine, VASILEIOS TZELEPIS 2015 University of New Orleans

Electromechanics Of An Ocean Current Turbine, Vasileios Tzelepis

University of New Orleans Theses and Dissertations

The development of a numeric simulation for predicting the performance of an Ocean Current Energy Conversion System is presented in this thesis along with a control system development using a PID controller for the achievement of specified rotational velocity set-points. In the beginning, this numeric model is implemented in MATLAB/Simulink® and it is used to predict the performance of a three phase squirrel single-cage type induction motor/generator in two different cases. The first case is a small 3 meter rotor diameter, 20 kW ocean current turbine with fixed pitch blades, and the second case a 20 meter, 720 ...


Design Of A Solar Tracking System For Improving Solar Photovoltaic Efficiency, Dr. Adel A. Elbaset 2015

Design Of A Solar Tracking System For Improving Solar Photovoltaic Efficiency, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

The aim of this work is to develop a microcontroll
er-based solar tracking system and assess the value of using
single and dual-axis solar trackers as means for improving the
performance of photovoltaic generation systems. Two
experimental test setups were designed, implemented and
used to collect the evaluation results at a site that is located
at 28° N latitude, 31° E longitude. One of the test setups
included a monocrystalline photovoltaic (PV) panel that is fixed
at a reference inclination angle of 28° with respect to the horizon,
and facing due south. Whereas, the other experimental setup
included an identical ...


Reliability/Economic/Ghg Implications Of Grid-Connected Wind Energy System Based On Genetic Algorithm, Dr. Adel A. Elbaset 2015

Reliability/Economic/Ghg Implications Of Grid-Connected Wind Energy System Based On Genetic Algorithm, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

Greenhouse gas, economic, and reliability issues are becoming more important for the emerging wind markets worldwide. With the interconnection of wind energy system into the electric grid, the fluctuating nature of the energy produced has a different effect on the overall system reliability/economic and GHG emissions as well as the fluctuating nature of energy produced by grid. Optimum reliability/economic and pollutant emission are multi-objective problem because reliability is conflicting with annual cost and GHG emissions. The reliability index is analyzed using probabilistic concept in order to find loss of load probability and annual customer damage cost. Therefore, this ...


Design And Implementation Of Microcontroller Based Non-Inverting Dc/Dc Buck-Boost Converter, Hamdi Ali Mohamed 2015

Design And Implementation Of Microcontroller Based Non-Inverting Dc/Dc Buck-Boost Converter, Hamdi Ali Mohamed

Dr. Adel A. Elbaset

This paper design a low cost non-inverting DC/DC buck-boost converter to produce constant output voltage with high reliability and simple control manner. The proposed controller is based on closed loop voltage mode control technique with microcontroller (atmega8) to stabilize the output voltage of DC/DC converter. The microcontroller adjusts the duty cycles of the power switches according to the measured output voltage within limited range of the input voltage of DC/DC converter. The proposed DC/DC converter is simulated on Proteus Suite and experimentally implemented in continuous conduction mode (CCM) with unregulated DC input voltage between 8-25Vand 62 ...


Modeling Of Photovoltaic Module Based On Two-Diode Model, Dr. Adel A. Elbaset 2015

Modeling Of Photovoltaic Module Based On Two-Diode Model, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

Abstract—Modeling of Photovoltaic (PV) system represents
very important goal for design and performance of PV system.
This paper presents a new method based on two-diode model to
estimate seven-parameter of PV module to describe I-V and P-V
characteristic curves at different solar radiations and
temperatures. Newton-Raphson method is used with the aid of
initial values of seven-parameter that are derived from basic
equations of two-diode model and manufacturing datasheet at
standard test conditions (STC) to compute accurate values of
these parameters. The proposed model is validated on two
different PV modules of multi-crystalline and thin-film. I-V and
P-V characteristics ...


The Non Ideality Effect Of Optimizing The P&O Mppt Algorithm For Pv Ac Load Applications, Dr. Adel A. Elbaset 2015

The Non Ideality Effect Of Optimizing The P&O Mppt Algorithm For Pv Ac Load Applications, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

Maximum power point tracking (MPPT) techniques are used in photovoltaic (PV) systems to maximize the PV array output power by tracking continuously the maximum power point (MPP), which depends on panels' temperature and irradiance conditions. The perturb and observe (P&O) MPPT algorithm is the most commonly used method due to its ease of implementation. However, it has some drawbacks such as the oscillation of the operating point around the MPP at steady state, which raises the waste of some amount of available energy. In addition, the P&O algorithm can be confused by rapidly changing atmospheric conditions. In this ...


Optimal Tuning Of Pi Controller Parameters For Three- Phase Ac-Dc-Ac Converter Based On Particle Swarm Algorithm, Dr. Adel A. Elbaset 2015

Optimal Tuning Of Pi Controller Parameters For Three- Phase Ac-Dc-Ac Converter Based On Particle Swarm Algorithm, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

Usually proportional-integral (PI) controller tuning
rules are derived based on linear models of the plant or process,
without taking nonlinearities into account. Hence, the best
control performance cannot be ensured. This paper presents
optimal tuning method based on more accurate nonlinear models
of the three-phase voltage regulator converter. This nonlinear
model is considered as objective function with input arguments of
proportional gain and integral gain, besides its output is the
integral of time multiply squared error (ITSE) of PI controller.
The measure of ITSE error is used to depict the system
performance i.e. the fitness function. Using optimization method ...


Numerical Simulations Of Negative Flexural Responses (Hogging) In Railway Prestressed Concrete Sleepers, Sakdirat Kaewunruen, Tetsuya Ishida, Alex M Remennikov 2015

Numerical Simulations Of Negative Flexural Responses (Hogging) In Railway Prestressed Concrete Sleepers, Sakdirat Kaewunruen, Tetsuya Ishida, Alex M Remennikov

Sakdirat Kaewunruen


By the very nature of ballast, it interacts with concrete sleepers in a special way. Most train-track models do not consider its tensionless characteristics and cannot accurately predict dynamic responses of structural components in railway tracks. This study has taken into account its natural tensionless property in order to investigate reverse bending moment at the mid span of standard-gauge concrete sleepers, which causes some concerns in many countries. It has been reported that the excessive negative bending moment at the mid span results in associated flexural cracks and centre-bound problems in rail freight and heavy haul networks especially in North ...


Dynamic Properties Of Early-Age Micro- And Nano-Engineered Concrete For Compliant Railway Structures, Ratthaphong Meesit, Sakdirat Kaewunruen, Paramita Mondal 2015 University of Birmingham, UK

Dynamic Properties Of Early-Age Micro- And Nano-Engineered Concrete For Compliant Railway Structures, Ratthaphong Meesit, Sakdirat Kaewunruen, Paramita Mondal

Sakdirat Kaewunruen


Cementitious materials modified by micro- and nano-engineered crumb rubber particles are robust and resilient materials capable of mitigating large-strain and large-amplitude vibrations in a dynamic compliant structure such as in railway traffic environments under heavy freight or high speed rail operation. The improvement of fundamental dynamic properties encourages the applications of engineered concrete to railway and civil constructions. Such the improvement has significant potential to mitigate pressing issues in modern railway industry such as rail seat abrasion and impact damages in concrete sleepers, thermal expansion crack of track slabs, and so on. Also indirectly, the utilisation of crumb rubber will ...


Diagnostic Of Flexural Damage On Railway Prestressed Concrete Sleepers Using Dynamic Modal Responses, Sakdirat Kaewunruen, Kaio Jara Faria 2015

Diagnostic Of Flexural Damage On Railway Prestressed Concrete Sleepers Using Dynamic Modal Responses, Sakdirat Kaewunruen, Kaio Jara Faria

Sakdirat Kaewunruen

Flexural damages in railway prestressed concrete sleepers are often hidden from visual inspections during track monitoring and maintenance activities. Often, small cracks can sometimes be generated due to aggressive dynamic actions. These cracks indicate a level of serviceability of the railway sleepers. Severe cracks can impair rail gauge stability due to large rail inclinations. This gauge instability can cause train derailments, especially in curves and transitions where lateral train force incurs coincide with unstable two point contacts between wheel and rail. An attempt to develop a non-destructive diagnostic tool for  structural health of prestressed concrete sleepers in railway tracks using ...


Experimental Investigation And Thermal Modeling On Electro Discharge Drilling Of Pcd, Farnaz Nourbakhsh 2015 University of Nebraska-Lincoln

Experimental Investigation And Thermal Modeling On Electro Discharge Drilling Of Pcd, Farnaz Nourbakhsh

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

This study presents an experimental investigation and finite element simulation of Electro Discharge Drilling (ED-Drilling) of Polycrystalline Diamond (PCD). PCD has many outstanding properties including uniformly high hardness, high wear resistance and strong corrosion which are the main causes of widely using PCD. While PCD has many advantages and an important role in industrial applications, its high level of hardness and wear resistance cause this material to be difficult to form and machine by using traditional machining methods. EDM as a nontraditional machining process is an effective method among other non-traditional methods for PCDs due to its low cost and ...


Failure Simulations At Multiple Length Scales In High Temperature Structural Alloys, Chao Pu 2015 University of Tennessee - Knoxville

Failure Simulations At Multiple Length Scales In High Temperature Structural Alloys, Chao Pu

Doctoral Dissertations

A number of computational methodologies have been developed to investigate the deformation and damage mechanism of various structural materials at different length scale and under extreme loading conditions, and also to provide insights in the development of high-performance materials.

In microscopic material behavior and failure modes, polycrystalline metals of interest include heterogeneous deformation field due to crystalline anisotropy, inter/intra grain or phase and grain boundary interactions. Crystal plasticity model is utilized to simulate microstructure based polycrystalline materials, and micro-deformation information, such as lattice strain evolution, can be captured based on crystal plasticity finite element modeling (CPFEM) in ABAQUS. The ...


Field And Laboratory Study Of The Flàajökull Glacier, Iceland, William Russell Jacobson, Jr. 2015 University of Wisconsin-Milwaukee

Field And Laboratory Study Of The Flàajökull Glacier, Iceland, William Russell Jacobson, Jr.

Theses and Dissertations

The increased surface melting of the outlet glaciers of the Vatnajökull Ice Cap has a profound affect on the dynamics of the ice-bed couple and landform genesis. Soft-bedded glaciers are largely inaccessible, which creates a problem. One challenge is to understand the complex interactions of the glacier bed and its resultant depositional and deformational landform systems. This study investigates an outlet glacier from the Vatnajökull Ice Cap, described herein as the Fláajökull glacier system. To circumvent some of these problems, three separate projects were conducted in this dissertation: (1) magnetic fabric study of effective pressure (difference between the ice-overburden pressure ...


Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett 2015 US Army Corps of Engineers

Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett

Sinkhole Conference 2015

The US Army required construction of a 2,787.1 square meters (30,000 sf) maintenance facility supported on shallow foundations at the Fort Campbell Military Installation. During the subsurface investigation a seven foot air-filled void was encountered in the bedrock within the building footprint. Electrical Resistivity Imaging (ERI) was conducted in an attempt to determine the lateral extent of the encountered void and to establish the general prevalence of karst features at the site. Due to uncertainty in the subsurface conditions, a rock treatment and soil modification program was developed which consisted of a series of targeted exploratory grout ...


Elevated Test Pressure Significantly Reduces Dynamic Accumulation Oxygen Transmission Rate (Astm F3136) Measurement Time For Barrier Packaging Films, Bruce A. Welt 2015 University of Florida

Elevated Test Pressure Significantly Reduces Dynamic Accumulation Oxygen Transmission Rate (Astm F3136) Measurement Time For Barrier Packaging Films, Bruce A. Welt

Journal of Applied Packaging Research

Measurement of gas transmission rates of materials is important for successful package design. The dynamic accumulation (DA) method (ASTM F3136) is becoming increasingly popular for measuring oxygen transmission rate (OTR) due to its simplicity and low cost. However, measurement time increases with barrier properties of materials, limiting measurement throughput. A dynamic accumulation measurement prototype capable of operating up to 1,000 psig was developed in order to accelerate gas transfer by boosting concentration gradients via elevated absolute pressures. Results show that measurement results were independent of test pressure while measurement times were substantially reduced. These results also suggest that gas ...


Electromechanical Coupling Behavior Of Dielectric Elastomer Transducers, Jianyou Zhou 2015 The University of Western Ontario

Electromechanical Coupling Behavior Of Dielectric Elastomer Transducers, Jianyou Zhou

Electronic Thesis and Dissertation Repository

Dielectric elastomer transducers with large deformation, high energy output, light weight and low cost have been drawing great interest from both the research and industry communities, and shown potential for versatile applications in biomimetics, dynamics, robotics and energy harvesting. However, in addition to multiple failure modes such as electrical breakdown, electromechanical instability, loss-of-tension and fatigue, the performance of dielectric elastomer transducers are also strongly influenced by the hyperelastic and viscoelastic properties of the material. Also, the interplay among these material properties and the failure modes is rather difficult to predict. Therefore, in order to provide guidelines for the optimal design ...


Iron Pigments Through The Ages, Fathi Habashi 2015 Laval University, Quebec City, Canada

Iron Pigments Through The Ages, Fathi Habashi

Fathi Habashi

Naturally occurring iron oxides were used since ancient times as ochre yellow and red pigments. It was only in the 18th century that artificially prepared Prussian blue was discovered. This discovery opened up a new field of chemistry - - cyano compounds.


Structure And Optical Properties Of Transition Metal Dichalcogenides (Tmds) – Mx2 (M = Mo, W & X = S, Se) Under High Pressure And High Temperature Conditions, Nirup Reddy Bandaru 2015 University of Nevada, Las Vegas

Structure And Optical Properties Of Transition Metal Dichalcogenides (Tmds) – Mx2 (M = Mo, W & X = S, Se) Under High Pressure And High Temperature Conditions, Nirup Reddy Bandaru

UNLV Theses/Dissertations/Professional Papers/Capstones

Layered structured materials such as transition metal dichalcogenides (TMDs) have gained immense interest in recent times due to their exceptional structural, electrical and optical properties. Recent studies show semiconducting TMDs such as MX2 (M= Mo, W

& X = S, Se) could be used as potential shock absorbing material, which has resulted in extensive studies on structural stability of these materials under the influence of high pressure. Understanding the structural stability of transition metal dichalcogenides (TMDs) such as MoS2, MoSe2, WS2, and WSe2 under high pressure has been very challenging due to contradicting observations and interpretations reported in the past. Hence, the ...


Feasibility Study Of Custom Manufacturing Of Ionic Polymer-~Metal Composite Sensors, Shelby E. Nelson 2015 University of Nevada, Las Vegas

Feasibility Study Of Custom Manufacturing Of Ionic Polymer-~Metal Composite Sensors, Shelby E. Nelson

UNLV Theses/Dissertations/Professional Papers/Capstones

The ability to create an ion exchange membrane with any shape or thickness through custom manufacturing techniques is highly desirable in ionic polymer-metal composite (IPMC) research. This is caused by the poor selection and limited availability of certain thicknesses of commercial ion exchange membranes. The objective of this study is to determine the feasibility of manufacturing custom ion exchange membranes for IPMC sensors. The manufacturing methods used in this study are extrusion, injection molding, and hot pressing. A commercial membrane from Golden Energy Fuel Cells (GEFC) is used as a comparison. After the membranes are fabricated, certain properties of the ...


Effect Of Surface Omniphobicity On Drying By Forced Convection, Madani A. Khan, Jeffrey Alston, Andrew Guenthner 2015 The City College of New York

Effect Of Surface Omniphobicity On Drying By Forced Convection, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR (STEM Teacher and Researcher) Program Posters

Low energy surfaces can strongly repel both oil and water. Recently these surfaces have been fabricated on various substrates including fabric, aluminum, stainless steel and many other materials. In this experiment we explore the use of low energy surface deposition on aluminum alloy, stainless steel and silicon substrates, to enhance the drying rate of liquids removed from the surface by forced convection. We control surface roughness by substrate abrasion and by the growth of Al2O3 nanograss to enhance liquid repellence by use of a hierarchical texture. Liquid repellence of the substrates is measured by contact angles of ...


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