Mechanical Engineering Commons^™

Evaluation And Forecast Of Energy Consumption In Different Sectors Of The United States Using Artificial Neural Networks, Arash Kialashaki

Theses and Dissertations

The United States is a country which consumes a vast amount of energy. In order to keep the development of the United States sustainable (diverse and productive over the time) energy planning should be carried out comprehensively and precisely. This dissertation presents a specific mathematical modeling approach towards energy demand modeling of the United States and forecast future energy demand. To generate more detailed and accurate results, this dissertation investigates the energy demand of each sector separately using the analysis of trend for unique set of independent parameters which affect the energy demand in that sector.

In solving a forecast …

Design And Model Of The Frame For Hagrid (Hybrid Array Of Gamma Ray Detectors), Santiago Munoz

Masters Theses

Transfer reactions in inverse kinematics have provided critical information in the study of exotic nuclei. However, transfer reactions with charged particles suffer from poor resolution. The measurement of gamma-rays offers several advantages: they provide not only good resolution in measurements but also other information about the nuclei like lifetimes of unstable states. The combination of these two methods would be the ideal situation to gather information about nuclear structure.

HAGRiD, which stands for The Hybrid Array of Gamma Ray Detectors, is a LaBr3(Ce) [lanthanum bromide crystal with a cerium activator] scintillation array to measure gamma rays from transfer reactions and …

Analysis And Optimization Of The Scheffler Solar Concentrator, Simone Alberti

Master's Theses

The Scheffler reflector is a new solar concentrator design which maintains a fixed focus while only having a single axis tracking mechanism. This design makes the construction and operation of high temperature solar concentrators accessible to developing nations. In this project, I wrote computer simulation codes to better understand the dynamics and the effect of deformation or deviations from ideal conditions in order to define necessary manufacturing and operational tolerances. These tools and knowledge drove the prototyping of new reflector concepts by myself and other students on my team. A fiberglass prototype was able to drive the cost of a …

Mitigation Of Moving Shocks In An Expanding Duct, Veraun Chipman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Inviscid flow theory governs the bulk motion of a gas at some distance away from the walls (i.e. outside the boundary layer). That is to say, there are no viscous forces in the bulk flow, which is modeled using the Euler equations. The Euler equations are simply the Navier-Stokes equations with zero viscosity terms. An ideal inviscid fluid, when brought into contact with a surface or wall, would naturally slip right past it since the fluid has no viscosity. In real life, however, a thin boundary layer forms between the wall or surface and the bulk flow. Shock wave boundary …

The Development Of A Laminated Copolyester Electric Guitar, Addison S. Karnes

Electronic Theses and Dissertations

This thesis is an investigation of the fabrication and assembly methodologies employed in the development of a proof-of-principle prototype electric guitar composed of laminated copolyester. The objective of the project was to develop the processes and procedures to create an optimized physical and visual bond between layers to minimize vibratory dissipation, thus maximizing sustain. A high speed CNC router, abrasive waterjet, laser engraver-cutter, as well as various manual fabrication and assembly methods were investigated in the construction of the guitar prototypes. The lamination processes explored include low-temperature, heat-assisted pressure bonding, solvent and chemical welding, and contact adhesives. The project concluded …

Designing A Biomimetic Testing Platform For Actuators In A Series-Elastic Co-Contraction System, Ryan Tyler Schroeder

UNLV Theses, Dissertations, Professional Papers, and Capstones

Actuators determine the performance of robotic systems at the most intimate of levels. As a result, much work has been done to assess the performance of different actuator systems. However, biomimetics has not previously been utilized as a pretext for tuning a series elastic actuator system with the purpose of designing an empirical testing platform. Thus, an artificial muscle tendon system has been developed in order to assess the performance of two distinct actuator types: (1) direct current electromagnetic motors and (2) ultrasonic rotary piezoelectric motors. Because the design of the system takes advantage of biomimetic operating principles such as …

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …

Dropwise Condensation Dynamics In Humid Air, Julian Eduardo Castillo Chaco

Open Access Theses

Dropwise condensation of atmospheric water vapor is important in multiple practical engineering applications. The roles of environmental factors and surface morphology/chemistry on the condensation dynamics need to be better understood to enable efficient water-harvesting, dehumidication, and other psychrometric processes. Systems and surfaces that promote faster condensation rates and self-shedding of condensate droplets could lead to improved mass transfer rates and higher water yields in harvesting applications. The thesis presents the design and construction of an experimental facility that allows visualization of the condensation process as a function of relative humidity. Dropwise condensation experiments are performed on a vertically oriented, hydrophobic …

Waste Heat Recovery Options In A Large Gas-Turbine Combined Power Plant, Ularee Upathumchard

Open Access Theses

This study focuses on power plant heat loss and how to utilize the waste heat in energy recovery systems in order to increase the overall power plant efficiency. The case study of this research is a 700-MW natural gas combined cycle power plant, located in a suburban area of Thailand. An analysis of the heat loss of the combustion process, power generation process, lubrication system, and cooling system has been conducted to evaluate waste heat recovery options. The design of the waste heat recovery options depends to the amount of heat loss from each system and its temperature. Feasible waste …

Algebraic Level Sets For Cad/Cae Integration And Moving Boundary Problems, Kritika Upreti

Open Access Dissertations

Boundary representation (B-rep) of CAD models obtained from solid modeling kernels are commonly used in design, and analysis applications outside the CAD systems. Boolean operations between interacting B-rep CAD models as well as analysis of such multi-body systems are fundamental operations on B-rep geometries in CAD/CAE applications. However, the boundary representation of B-rep solids is, in general, not a suitable representation for analysis operations which lead to CAD/CAE integration challenges due to the need for conversion from B-rep to volumetric approximations. The major challenges include intermediate mesh generation step, capturing CAD features and associated behavior exactly and recurring point containment …

High Voltage Rear Electric Drivetrain Design For A Parallelthrough-The-Road Plug-In Hybrid Electric Vehicle, Adam Garrett Fogarty

Open Access Theses

Purdue University was selected as one of 15 universities to participate in a three year Advanced Vehicle Technology Competition (AVTC) called EcoCar2: Plugging Into the Future. The vehicle built by the Purdue team was a Parallel-Through-The-Road Plug-in Hybrid Electric Vehicle (PTTR PHEV). The vehicle utilized a B20 diesel powertrain to power the front wheels, as well as a custom electric drivetrain to power the rear wheels. Using this vehicle during the final year of the competition, the team was successful in placing 4th overall as well as 2nd in the category of Well-To-Wheel (WTW) Greenhouse Gas Emissions. A stock 2013 …

Indoor Acoustic Mapping And Geolocation, Thomas Shyy

Open Access Theses

The Global Positioning System (GPS) is widely used in navigations of flights, vehicles and travelers nowadays. However, the signals are not always available and there are some cases where the receptions of the GPS signal can be lost because of the presence of urban canyons, buildings, tunnels and forests. Another down side for the GPS is that indoor positioning can be really difficult because of the greater signal interference from the indoor.

On the other hand, the concept of echolocation has also been used for positioning purposes. Echolocation offers a promising approach to improve the quality of life of people …

A Method To Develop Neck Injury Criteria To Aid Design And Test Of Escape Systems Incorporating Helmet Mounted Displays, Jeffrey C. Parr

Theses and Dissertations

HMDs are becoming common human-machine interface equipment in manned military flight, but introducing this equipment into the overall aircraft escape system poses new and significant system design, development, and test concerns. Although HMDs add capabilities, which improve operator performance, the increased capability is often accompanied by increased head supported mass. The increased mass can amplify the risk of pilot neck injury during ejection when compared to lighter legacy helmets. Currently no adequate USAF neck injury criteria exist to effectively guide the requirements, design, and test of escape systems for pilots with HMDs. This research effort presents a novel method to …

Creasing Instability Of Hydrogels And Elastomers, Dayong Chen

Doctoral Dissertations

CREASING INSTABILITY OF HYDROGELS AND ELASTOMERS MAY 2014 DAYONG CHEN, B.S., TIANJIN UNIVERISTY M.S., TIANJIN UNIVERSITY M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Ryan C. Hayward Soft polymers placed under compressive stress can undergo an elastic creasing instability in which sharp folds spontaneously form on the free surfaces. This process may play an important role in contexts as diverse as brain morphogenesis, failure of tires, and electrical breakdown of soft polymer actuators. While the creasing instability has been used for collotype printing since as early as the 1850s, the scientific appreciation of this instability …

Investigation Of Concurrent Energy Harvesting From Ambient Vibrations And Wind, Amin Bibo

All Dissertations

In recent years, many new concepts for micro-power generation have been introduced to harness wasted energy from the environment and maintain low-power electronics including wireless sensors, data transmitters, controllers, and medical implants. Generally, such systems aim to provide a cheap and compact alternative energy source for applications where battery charging or replacement is expensive, time consuming, and/or cumbersome. Within the vast field of micro-power generation, utilizing the piezoelectric effect to generate an electric potential in response to mechanical stimuli has recently flourished as a major thrust area. Based on the nature of the ambient excitation, piezoelectric energy harvesters are divided …

Development And Applications Of The Expanded Equivalent Fluid Method, Bharath Kumar Kandula

Dissertations

Ocean acoustics is the study of sound in the oceans. Electromagnetic waves attenuate rapidly in the water medium. Sound is the best means to transmit information underwater. Computational numerical simulations play an important role in ocean acoustics. Simulations of acoustic propagation in the oceans are challenging due to the complexities involved in the ocean environment. Different methods have been developed to simulate underwater sound propagation. The Parabolic-Equation (PE) method is the best choice in several ocean acoustic problems. In shallow water acoustic experiments, sound loses some of its energy when it interacts with the bottom. An equivalent fluid technique was …

Development Of A Black-Box Transient Thermal Model For Residential Buildings, Andrew Cross

UNLV Theses, Dissertations, Professional Papers, and Capstones

Heavily populated metropolitan areas located in cooling-dominated climates, as are found in the Desert Southwest, pose a challenge to electrical utilities that service these areas. During the late afternoons of the summer months, residents of these metropolitan areas require larger than normal amounts of power to run their homes' air conditioning systems, at significant expense to the utilities. In the study reported here, interior temperature and power consumption data, accumulated over the course of a year and a half from seven houses within a Las Vegas neighborhood, are used to develop a predictive black-box statistical model for residential thermal transience. …

The Prediction Of Airborne And Structure-Borne Noise Potential For A Tire, Nicholas Sakamoto

Open Access Theses

Tire/pavement interaction noise is a major component of both exterior pass-by noise and vehicle interior noise. The current testing methods for ranking tires from loud to quiet require expensive equipment, multiple tires, and/or long experimental set-up and run times. If a laboratory based off-vehicle test could be used to identify the airborne and structure-borne potential of a tire from its dynamic characteristics, a relative ranking of a large group of tires could be performed at relatively modest expense. This would provide a smaller sample set of tires for follow-up testing and thus save expense for automobile OEMs. The focus of …

Study Of A Generalized Empirical Model For Predicting Pressure Drop For Internal Flows, Tejas Anup Pant

Open Access Theses

A generalized empirical model for estimating the pressure drop across a channel for a given massflow rate is studied through computational fluid dynamics (CFD) simulations. It is observed that for developing laminar and turbulent flow through channels and pipes of arbitrary cross-section, the variation in the pressure drop between any two points in the flow direction with massflow rate can be well approximated by a second degree expression in massflow rate which is referred to as the empirical model in this study. In the first part of this study, a correlation between the pressure gradient and the massflow rate is …

Experimental Study Of Unsteady Heat Release In An Unstable Single Element Lean Direct Injection (Ldi) Gas Turbine Combustor, Varun S. Lakshmanan

Open Access Theses

In an effort to curb emissions from gas turbine engines, many low emission engine concepts have been developed. Among the most promising of these is the LDI (Lean Direct Injection). These systems operate at relatively low equivalence ratios close to blowout and are prone to instabilities. Combustion instabilities can reduce the life of the combustor by causing large pressure fluctuations and enhanced heat release to the walls of the combustor and reduce the efficiency of the engines. The understanding of combustion instabilities is vital to the implementation of such systems. Combustion instabilities are studied in an self-excited single element gas …

A Novel Microgrid Demand-Side Management System For Manufacturing Facilities, Terance Jerome Harper

Open Access Theses

Thirty-one percent of annual energy consumption in the United States occurs within the industrial sector, where manufacturing processes account for the largest amount of energy consumption and carbon emissions. For this reason, energy efficiency in manufacturing facilities is increasingly important for reducing operating costs and improving profits. Using microgrids to generate local sustainable power should reduce energy consumption from the main utility grid along with energy costs and carbon emissions. Also, microgrids have the potential to serve as reliable energy generators in international locations where the utility grid is often unstable.

For this research, a manufacturing process that had approximately …

High Temperature Flooded Expansion For Solar Thermal Power Generation, Nelson Alexander James

Open Access Theses

Even though solar power usage has seen rapid growth over the past decade, fossil fuel generation sources are still generally a less expensive means of producing power. The Liquid-Flooded Ericsson Cycle (LFEC) was investigated as a high efficiency power cycle for reducing the cost of concentrated solar power (CSP) plants and helping to address this cost disparity. High temperature flooded expansion was identified as one of the main challenges in regards to utilizing the LFEC as a power cycle. Thermodynamic models were developed to help assess the performance of the LFEC and a load stand was constructed to test a …

Aerodynamic Study Of Forces Due To Wind Velocity And Angle Of Attack On Parabolic Solar Troughs, Brian Northshield

Doctoral Dissertations and Master's Theses

Scant literature exists of the atmospheric effects on parabolic solar troughs. The technology is relatively new, so supporting studies by consequence are as well.

This study examines the effects of wind at various speeds, with various angles of attack on parabolic solar troughs. This begins by picking up on previous study, corroborating previously found data, then introduces new angles of attack. The model includes the presence of the solar tube where other studies omit.

The purpose of this study is to build a data set which is useful for structural consideration. During the course of this study, it was found …

Meshless Mechanics And Point-Based Visualization Methods For Surgical Simulations, Rifat Aras

Computational Modeling & Simulation Engineering Theses & Dissertations

Computer-based modeling and simulation practices have become an integral part of the medical education field. For surgical simulation applications, realistic constitutive modeling of soft tissue is considered to be one of the most challenging aspects of the problem, because biomechanical soft-tissue models need to reflect the correct elastic response, have to be efficient in order to run at interactive simulation rates, and be able to support operations such as cuts and sutures.

Mesh-based solutions, where the connections between the individual degrees of freedom (DoF) are defined explicitly, have been the traditional choice to approach these problems. However, when the problem …

Lightweight Uav Launcher, Ben Miller, Christian Valoria, Corinne Warnock, Jake Coutlee

Mechanical Engineering

This report discusses the design, construction, and testing of a lightweight, portable UAV launcher. There is a current need for a small team of soldiers to launch a US Marine Tier II UAV in a remote location without transport. Research was conducted into existing UAV launcher designs and the pros and cons of each were recorded. This research served as a basis for concept generation during the initial design development stage. It was required that the design weigh less than 110 lbs, occupy a smaller volume than 48" x 24" 18" in its collapsed state, be portable by a single …

Looking For Small Changes In Heat Capacity Using A Differential Scanning Calorimeter, Will Linthicum

Honors Theses

One of the major difficulties in development of renewable energy is the lack of an adequate and economical means of energy storage. In the case of concentrated solar power a large mass of thermal fluid is required to store a reasonable amount of energy. This is primarily because the fluids tend to have a low specific heat capacity. Formulating composites of these fluids can enhance their specific heat capacity and avails opportunities to make concentrated solar power more attractive. In most cases, the specific heat capacity of composite materials is a weighted average of the individual component heat capacities. This, …

Wetting, Superhydrophobicity, And Icephobicity In Biomimetic Composite Materials, Vahid Hejazi

Theses and Dissertations

Recent developments in nano- and bio-technology require new materials. Among these new classes of materials which have emerged in the recent years are biomimetic materials, which mimic structure and properties of materials found in living nature. There are a large number of biological objects including bacteria, animals and plants with properties of interest for engineers. Among these properties is the ability of the lotus leaf and other natural materials to repel water, which has inspired researchers to prepare similar surfaces. The Lotus effect involving roughness-induced superhydrophobicity is a way to design nonwetting, self-cleaning, omniphobic, icephobic, and antifouling surfaces. The range …

Design Of A Custom Software Application To Monitor And Communicate Cnc Machining Process Information To Aid In Chatter Identification, Valerie Pezzullo

All Theses

In any manufacturing environment, it is important to be able to monitor the Computer Numerical Control (CNC) machining process so that high quality parts can be produced in the least amount of time in order to be profitable. This involves acquiring the proper parameters needed from the machine's controller, which can prove to be difficult with proprietary machine tools that tend to limit access to the internal data collected by the controller. This closed approach to controller design also means that many technological advances that have recently become prevalent in society are not being adopted in the manufacturing industry, preventing …

Study Of Water Transport Phenomena On Cathode Of Pemfcs Using Monte Carlo Simulation, Karn Soontrapa

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation deals with the development of a three-dimensional computational model of water transport phenomena in the cathode catalyst layer (CCL) of PEMFCs. The catalyst layer in the numerical simulation was developed using the optimized sphere packing algorithm. The optimization technique named the adaptive random search technique (ARSET) was employed in this packing algorithm. The ARSET algorithm will generate the initial location of spheres and allow them to move in the random direction with the variable moving distance, randomly selected from the sampling range, based on the Lennard-jones potential of the current and new configuration. The solid fraction values obtained …

Ionic Copolymers For Alkaline Anion Exchange Membrane Fuel Cells (Aaemfcs), Tsung-Han Tsai

Doctoral Dissertations

The advantages of alkaline anion exchange membrane fuel cells (AAEMFCs) over proton exchange membrane fuel cells is the motivation for this dissertation. The objectives of this dissertation were to develop durable membranes with high anion conductivity and an understanding of the ion conductivity relationship with morphology. The research results presented in this dissertation focuses on developing different architectures of ionic copolymers including diblock copolymers and random copolymers for AAEMFCs. A novel, and stable cobaltocenium cation, was incorporated into polymer for stable AAEM. Because of its 18 electron closed valence-shell configuration, the cobaltocenium cation is promising for use in AAEMFC. Two …