Mechanical Engineering Commons^™

Design Of A Thermal Management System For An Oxy-Methane Direct Power Extraction Combustor, Jad Gerges Aboud

Open Access Theses & Dissertations

The overarching goal of this Thesis is to present the design of a thermal management system for an oxy-methane direct power extraction combustor. The design is initiated by performing a 2D analysis on the combustor geometry and then using these results in a 3D model. This is done by using results for heat transfer coefficient and temperatures found from the 2D simulation and importing these to the 3D model. The approach used here couples the combustion process, heat transfer through the chamber wall, and fluid flow behaviors in order to observe the thermal characteristics of the combustor during operation. This …

Structural, Dielectric, And Ferroelectric Characterization Of Lead-Free Calcium-Cerium Co-Doped Batio3 Ceramics, Juan Alberto Duran

Open Access Theses & Dissertations

Structure, morphology, and regulation of the dielectric properties via close-composition intervals is demonstrated for variable-cerium, constant-calcium co-doped barium titanate (Ba0.80Ca0.20CeyTi1-yO3; y=0.0-0.25; referred to BCCT). The effect of variable Ce-content on the structure and dielectric properties of BCCT is investigated. X-ray diffraction spectra confirms the studied samples are mainly in BT tetragonal phase with a small secondary phase detected as CaTiO3 in BCCT for y = 0.20 and 0.25. However, the lattice parameter reduction was evident with increasing Ce-content. Composition-driven dielectric constant leap (4,000-5,500) was observed from intrinsic BCT to BCCT for (y = 0.0-0.04). The temperature dependent dielectric constant showed …

Design And Experimental Investigation Of An Oxy-Fuel Combustion System For Magnetohydrodynamic Power Extraction, Manuel Johannes Hernandez

Open Access Theses & Dissertations

A general consensus in the scientific and research community is the need to restrict carbon emissions in energy systems. Therefore, extensive research efforts are underway to develop the next generation of energy systems. In the field of power generation, researchers are actively investigating novel methods to produce electricity in a cleaner, efficient form. Recently, Oxy-Combustion for magnetohydrodynamic power extraction has generated significant interest, since the idea was proposed as a method for clean power generation in coal and natural gas power plants. Oxy-combustion technologies have been proposed to provide high enthalpy, electrically conductive flows for direct conversion of electricity. Direct …

Design And Performance Evaluations Of A Lo2/Methane Reaction Control Engine, Aaron Johnson

Open Access Theses & Dissertations

Liquid oxygen (LOX) and liquid methane (LCH4) are a propellant combination viewed as a potential enabling technology for spacecraft propulsion. Reasons why LOX/LCH4 is being used as an alternative propellant source include: it is less toxic than other propellants, it has the possibility to be harvested on extraterrestrial soil, LCH4 has a higher energy density than liquid hydrogen (LH2; commonly used on vehicle main engines), and LOX/LCH4 has comparable performance to other well-known propellant combinations. Through the continued partnership between the National Aeronautics and Space Administration (NASA) and the University of Texas at El Paso (UTEP) a LOX/LCH4 reaction control …

Modeling And Testing Of Functional Materials For Energy System Applications, Hasanul Karim

Open Access Theses & Dissertations

Energy efficiency is one of the key concerns addressing the problem of global warming. Numerous research has been going on in order to improve the efficiency of energy conversion systems to reduce the polluted emission in the atmosphere. One of the approach is monitoring and maintaining the critical parameters of operation such as temperature to ensure the desired reactions, however, the harsh environment present in these systems makes the use of current temperature sensing solutions such very challenging to implement. Wireless temperature sensors are getting increasing attention as a potential solution, however, the need of energy storage devices such as …

Development And Testing Of Oxygen/Methane Torch Igniter Technologies For Propulsion Systems, Luis Eduardo Sanchez

Open Access Theses & Dissertations

The development and testing of an oxygen/methane torch ignition system as well as the evaluation process of the system are presented with the purpose of characterizing the properties and performance of methane as a fuel in a propulsion system. The experimental approach to this Dissertation entails the development and testing of a swirl torch igniter under conditions that may be seen when feeding propellant from the main storage tanks: combinations of gaseous and liquid oxygen and methane. The experimental goal of this Dissertation is to display the range of operability of the igniter technology presented leading to stable and consistent …

Mechanically Activated Combustion Synthesis Of Molybdenum Borosilicides For Ultrahigh-Temperature Structural Applications, Alan Alberto Esparza Hernandez

Open Access Theses & Dissertations

The desire to improve the efficiency of power generation gas-turbines has led to a relentless quest for new, ultrahigh-temperature structural materials to replace the current nickel-based superalloys. These materials have reached the maximum allowable operating temperature determined by the melting temperature of these alloys, which is about 1150 °C. These materials could be replaced by molybdenum silicides and borosilicides based on Mo5SiB 2 (T2) phase due to their high melting point and mechanical properties. A major challenge, however, is to simultaneously achieve high oxidation resistance and acceptable mechanical properties at elevated temperatures. One novel approach to improve these properties is …

Physics Based Modeling Of Guided Waves For Detection And Characterization Of Structural Damage In Nde And Shm, Banibrata Poddar

Theses and Dissertations

Guided waves based damage detection techniques are popular for their ease of generation and detection along with their ability to travel long distances. Accurate and efficient modeling is a key for successful implementation of guided waves for NDE/SHM. However, efficient prediction of scattering from various damage is challenging due to the complex nature of these guided waves.

This dissertation presents as physics based efficient and accurate modeling techniques to predict ultrasonic wave propagation and their interaction with various damage. Detection and characterization of damage in structures can typically be divided into two categories, active and passive. This research is aimed …

Determination Of Rejected Landing Roll Runway Point-Of-No-Return And Go-Around In Transport Category Airplanes, Nihad E. Daidzic, Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

The decelerate-accelerate-takeoff maneuver in transport category airplanes has been discussed. Mathematical model based on total energy conservation has been used to calculate the rejected landing point-of-no-return on a runway which will still enable the airplane to safely execute go-around and achieve regulatory screen heights and takeoff safety speeds. After this point has been exceeded or below the point-of-no-return speed no go-around should ever be considered. Landing long and fast and/or decelerating on slippery runways may very well result in an overrun which could be prevented if the go-around is attempted before reaching this critical runway point. The point-of-no-return on the …

On The Degradation Of Lubricating Grease, Asghar Rezasoltani

LSU Doctoral Dissertations

A comprehensive literature review on physical and chemical degradation monitoring and life estimation models for lubricating greases is presented in chapter one. Degradation mechanisms for lubricating grease are categorized and described, and an extensive survey of the available empirical and analytical grease life estimation models including degradation monitoring standards and methods are presented. In chapter two, irreversible thermodynamic theory is employed to study the mechanical degradation of lubricating grease. A correlation between the mechanical degradation and entropy generation is established and the results are verified experimentally using a rheometer, a journal bearing test rig, and a modified grease worker machine. …

Smart Tail-Light System, Julia Wood, Donald G. Haiss

Williams Honors College, Honors Research Projects

According to the National Highway Traffic Safety Administration (NHTSA) Safety Vehicle Research, 29% of all vehicle accidents are rear end collisions. Many are a result of failure to respond to a slowing or stopped vehicle. [1] The purposed LED rear lighting system will incorporate attention getting techniques to increase vehicle visibility to other drivers. Due to the small size and stature of the 2015 human powered vehicle called Joey, it will be out of the ordinary when traveling on roadways. “Three in four (72%) bicyclists who rode after dark said they tried to do something to make themselves more visible.” …

Cogeneration System Comparison For The Akron Water Treatment Plant, Devin J. Pearcy, Madison R. Morgan

Williams Honors College, Honors Research Projects

Cogeneration is a process of electrical power generation that simultaneously harnesses the heat produced from that electrical generation and uses it to supply heat to a space. The Akron Water Plant was identified as potentially benefitting from this technology for two main reasons. First, they have a large and relatively constant electrical load. Second, they have ownership of a significant amount of natural gas wells at the site.

This report analyzes the economic feasibility of installing a cogeneration plant at the Akron Water Plant (AWP). Data was collected for the plant and its operations, including electricity bills, gas bills, plant …

Design Of Surface Texture For The Enhancement Of Tribological Performance, Cong Shen

LSU Doctoral Dissertations

Surface texturing is a method of surface modification that fabricates micro patterns on the contacting surfaces to improve the tribological performance in sliding, lubricated system. It is found that the geometric design of textures has a significant influence on the performance of textured surfaces. Some important geometric parameters, such as the area ratio and the depth-over-diameter ratio, have been identified for textures in the form of circular dimples. The current study aims to improve the friction reduction effect of surface texturing by using textures with novel designs. Some new factors considered in the design of textures are: internal structure and …

Design And Commissioning Of A Community Scale Solar Powered Membrane-Based Water Purification System In Haiti, Shavin Pinto, Yung Wong, Kyle Fennesy, Yan Tang, Marc Compere

Publications

This paper presents the design and commissioning of a solar powered water purification system at the Ryan Epps Home for Children (REHC) in Michaud, Haiti. This system supplies clean drinking water to the 200 children who live and go to school at REHC and also to the community in the form of a micro-business. This micro-business is the mechanism for income generation for sustainable system operation. The purifier uses a three stage filtration system with a disc-type sediment filter, a 0.1 micron ultrafiltration membrane, and an ultraviolet light for disinfection. The backwash cycle extends the life of the ultrafiltration membrane …

Fatigue Properties Of Magnetorheological Elastomers And The Design Of Interfacial Layers To Improve Fatigue Life., Yanfen Zhou

Doctoral

The primary aim of this PhD programme was to understand the fatigue behaviour of magnetorheological elastomers (MREs) and provide a reliable fatigue life predictor for this class of materials. To realise this aim required the study of the dynamic behaviour of MREs using the equi-biaxial bubble inflation test method. Isotropic and anisotropic MREs were fabricated from silicone rubber (SR) filled with soft carbonyl iron (CI) particles. The equi-biaxial fatigue behaviour of these samples was determined using a bubble inflation method. Wohler (S-N) curves for both isotropic and anisotropic MREs were produced by subjecting the compounds to cycling over a range …

Creating Rigid Foldability To Enable Mobility Of Origami-Inspired Mechanisms, Alden Yellowhorse, Larry L. Howell

Faculty Publications

Rigidly foldable origami crease patterns can be translated into corresponding rigid mechanisms with at least one degree of freedom. However, origami crease patterns of interest for engineering applications are not always rigidly foldable, and designers trying to adapt a crease pattern may be confronted with the need to add more mobility to their design. This paper presents design guidelines for making alterations to a crease pattern to make it rigidly foldable. Adding creases, removing panels and splitting creases are presented as potential alterations for increasing mobility, and approaches for determining the position and number of alterations are discussed. This paper …

Integration Of Advanced Stiffness-Reduction Techniques Demonstrated In A 3d-Printable Joint, Larry L. Howell, Ezekiel G. Merriam, Kyler A. Tolman

Faculty Publications

his work details the integration of three distinct methods for altering the stiffness of compliant joints: lattice flexures, compound joints, and static balancing. The methodology for applying these strategies is discussed in detail. Lattice flexures are a flexure modification that leads to low motion-direction bending stiffness. Compound joints improve a compliant joint’s load-carrying ability and off-axis stiffness. Static balancing in this case is achieved through the addition of an auxiliary energy storage device. To statically balance a compound lattice-flexured cross-axis flexural pivot, the load-dependent stiffness behavior of a cross-axis flexural pivot (CAFP) with two lattice flexure types is determined. A …

Low-Velocity Impact To High-Temperature Low-Sag Overhead Conductors, Daniel Halka Waters

Electronic Theses and Dissertations

High-Temperature Low-Sag (HTLS) conductors, such as Aluminum Conductor Composite Core (ACCC), improve infrastructure to support the delivery of power to meet the nation's increasing demand for electricity. Their response to low-velocity impacts during transportation, installation or in service, however, has not been addressed in the past. Therefore, this study investigates both experimentally and numerically mechanical effects associated with transverse low-velocity impacts on energy dissipation by the conductors subjected to either free or constrained end conditions and large axial tensile loads. Impact experiments were conducted using a newly designed and manufactured testing apparatus. The experimental work was strongly supported by non-linear …

Landing Zone Determination For Autonomous Rotorcraft In Surveillance Applications, Timothy Mclain, Gary J. Ellingson, Justin Mackay

Faculty Publications

This paper presents an approach for finding possible landing sites for a rotorcraft from an inertially referenced point-cloud model of the environment. To identify potential landing sites that are suitably flat and level, a grid-based random sample consensus algorithm separates the terrain map into discrete areas for plane-fitting analysis. Landing sites are selected that satisfy constraints on flatness and levelness while optimizing the surveillance target’s visibility. Flight test results are presented from a small multirotor aircraft flying over a scale-model cityscape. Results from real-time landing-site experiments are presented and discussed.

Modeling Social, Economic, Technical & Environmental Components In An Energy System, Ange-Lionel Toba, Mamadou Seck

Engineering Management & Systems Engineering Faculty Publications

Energy system models have become the main supporting tool for energy policy. Modern challenges in energy policy require energy systems models that integrate technical, environmental and societal aspects of the energy systems. In this paper, we introduce a conceptual model for an energy system model that specifies the relationships between social, technical, environmental, and economic aspects of an energy system. This conceptual model presented in the IDEF0 language will serve as a basis for a computational energy systems model. © 2016 The Authors.

Equi-Biaxial Fatigue Testing Of Epm Utilising Bubble Inflation, Mark Johnson, Niall Murphy, Ray Ekins, John Hanley, Stephen Jerrams

Articles

This paper describes an equi-biaxial tension fatigue test system which utilises the bubble inflation method to subject elastomers to equi-biaxial fatigue loading between user-defined limits of pressure, volume, stretch ratio or stress. The test system integrates a hydraulic inflation system, a high speed vision system and a control system. The high-speed vision system allows the stretch ratio and stress acting on the test specimen to be evaluated in real-time during testing. This in turn allows either stretch ratio or stress to be used as a direct control limit. In this research, constant maximum engineering stress control tests have been carried …

Computational Tracking Of Shear-Mediated Platelet Interactions With Von Willebrand Factor, Adam Ralph, Martin Somers, Jonathan Cowman, Bruno Voisin, Emma Hogan, Hannah Dunne, Eimear Dunne, Barry Byrne, Nigel Kent, Antonio J. Ricco, Dermot Kenny, Simon Wong

Articles

The imaging of shear-mediated dynamic platelet behavior interacting with surface-immobilized von Willebrand factor (vWF) has tremendous potential in characterizing changes in platelet function for clinical diagnostics purposes. However, the imaging output, a series of images representing platelets adhering and rolling on the surface, poses unique, non-trivial challenges for software algorithms that reconstruct the positional trajectories of platelets. We report on an algorithm that tracks platelets using the output of such flow run experiments, taking into account common artifacts encountered by previously-published methods, and we derive seven key metrics of platelet dynamics that can be used to characterize platelet function. Extensive …

Experimental And Numerical Investigation Of Aerodynamic Performance For Vertical-Axis Wind Turbine Models With Various Blade Designs, Travis E. Salyers

College of Graduate Studies: Theses & Dissertations

The demand for wind energy as a renewable source is rising substantially. A growing interest exists in utilizing potential energy conversion applications in areas with less powerful and less consistent wind conditions. In these areas, vertical-axis wind turbines (VAWTs) possess several advantages over the conventional horizontal-axis type. Savonius turbines are drag-based rotors which operate due to a pressure difference between the advancing and retreating blades. These turbines are simpler in design, less expensive to install, non-dependent of wind direction, and more efficient in lower wind speeds. In the present study, six different rotor designs with equal swept areas are analyzed …

Scalability Of Microscale Fractal-Like Branching Channel Networks, James R. Miller Iii

Honors College Theses

Fractal-like branching channel networks have been shown to offer the advantages of reduced pumping power and lower maximum wall temperatures when employed in the design of microscale heat sinks. Unfortunately, previous literature has been limited to microscale flow networks. In this paper, a microscale flow network will be scaled up to result in a mesoscale flow network and a macroscale flow network. In order to compare the pressure drop across the flow networks of varying scales the results will be nondimensionalized in the form of the Euler number. For a laminar inlet Reynolds number the microscale, mesoscale, and macroscale fractal-like …

Project Oasis: Optimizing Aquaponic Systems To Improve Sustainability, Siddharth Nigam, Paige Balcom

Honors Theses and Capstones

Started in Fall 2015, Project OASIS (Optimizing Aquaponic Systems to Improve Sustainability) is an interdisciplinary capstone project with the goal of designing a sustainable and affordable small-scale aquaponic system for use in developing nations to tackle the problems of malnutrition and food insecurity. Aquaponics is a symbiotic relationship between fish and vegetables growing together in a recirculating system. The project’s goals were to minimize energy consumption and construction costs while using universally available materials. The computational fluid dynamics (CFD) software OpenFOAM was used to create transient and steady-state models of fish tanks to visualize velocity profiles, streamlines, and particle movement. …

Solar Photovoltaic System Control Topology Investigation For Power Source Mismatch, Lynette O'Callaghan

Conference papers

An investigation into solar photovoltaic (PV) system control topology selection, when partial shade is anticipated in the solar array, is presented. As available area is maximised in Building Integrated PV (BIPV) systems, shading is an inevitable consequence. The presence of partial shading in a PV array leads to multiple power peaks in the power-voltage curve, due to bypass diode sections being triggered, and an increase in module mismatch losses in the array. A building energy design software, Integrated Environmental Solutions, is used to determine the shadowed area on PV modules throughout the year, incorporating the PV system location and geometrical …

Investigation Of Humidity And Temperature Response Of A Silica Gel Coated Microfiber Coupler, Yuliya Semenova, Gerald Farrell, Dejun Liu

Conference Papers

The humidity and temperature responses of a microfiber coupler (MFC) coated with silica gel are investigated. Two MFC structures with different waist diameters of 2.5 and 3.5 μm were fabricated by fusing and tapering two single-mode fibers using a microheater brushing technique. The influences of the coating thickness and tapered waist diameter on the sensing performance are analyzed. For the proposed sensor with a waist diameter of 2.5 μm and 8-layers thick coating, the change in the relative humidity (RH) results in an exponential blueshift with a maximum sensitivity of 1.6 nm/% RH in the range from 70 to 86% …

The Relationship Of Corporate Financial Performance And Innovation Among Manufacturing Industries, Charlaine T. Chong, Samantha R. Chua, Ma. Catrina S. Dy, Antonio Miguel E. Villavicencio

Angelo King Institute for Economic and Business Studies (AKI)

Innovation is becoming a critical determinant of the survival and advancement of firms. Despite this realization, there is a dearth of literature that tackles the subject matter and its specific role in corporate settings remains vague. Using corporate data on East and Southeast Asian manufacturing firms from 2008 to 2013, this study aims to identify the impact of corporate financial performance on research and development (R&D) expenditure as a measure of innovation. On the whole, the researchers utilized random effects (REM) and fixed effects (FEM) models to establish the relationship between R&D and corporate performance. The researchers, then, identified the …

Effect Of Powder Particle Size On The Fabrication Of Ti-6al-4v Using Laser Metal Deposition From Elemental Powder Mixture, Xueyang Chen, Lei Yan, Wei Li, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct LMD (laser metal deposition) was used to fabricate thin-wall Ti-6Al-4V using the powder mixture of Ti-6 wt.%Al-4 wt.%V. SEM (scanning electron microscopy), OM (optical microscopy) and EDS (energy dispersive spectroscopy) were employed to examine the chemical composition and microstructure of the as-deposited sections. Vickers hardness tests were then applied to characterize the mechanical properties of the deposit samples which were fabricated using pre-mixed elemental powders. The EDS line scans indicated that the chemical composition of the samples was homogenous across the deposit. After significant analysis, some differences were observed among two sets of deposit samples which varied in the …

Aerodynamic And Modal Analyses Of Small Scale Horizontal Axis Wind Turbine With Various Numbers Of Blade Design, Emile Maroha

College of Graduate Studies: Theses & Dissertations

With the global energy demand rising to unprecedented numbers, the need for alternative energy sources is ever prevalent. Wind energy is the most alternative renewable sources today due to its year-round availability and pollution-free nature. Horizontal Axis Wind Turbines (HAWT) are the most popular because of their higher efficiency. The aerodynamic characteristics and vibration of small scale HAWT with various numbers of blade design have been investigated in this numerical study in order to improve its performance. SolidWorks was used for designing CAD models, and ANSYS software was used to study the dynamic flow around the turbine as well as …