Mechanical Engineering Commons^™

Enhancement Techniques Of Boiling Heat Transfer, Basim Qasim Ali Al-Sukaini

Doctoral Dissertations and Master's Theses

The aim of this study is to investigate pool boiling performance of water under atmospheric pressure by two techniques. The first method is by adding small amounts of surfactants, and the second way is by using structured surfaces.

The first technique is investigated experimentally with environmentally friendly surfactants. The surfactants chosen for the study are an ionic sodium lauryl sulfate (SLS), nonionic ECOSURF™ EH-14, and nonionic ECOSURF™ SA-9. It is observed that adding a small amount of surfactant alters the water boiling phenomenon significantly. Boiling curves for different concentrations are shifted to the left. The wall temperature drops greatly with …

Development Of A System Architecture For Unmanned Systems Across Multiple Domains, Charles Randall Breingan Jr.

Doctoral Dissertations and Master's Theses

In the unmanned systems industry, there is no common standard for systems components, connections and relations. Such a standard is never likely to exist. Needless to say, a system needs to have the components that are required for the application, however, it is possible to abstract the common functionality out of an individual implementation. This thesis presents a universal unmanned systems architecture that collects all of the common features of an unmanned system and presents them as a set of packages and libraries that can be used in any domain of unmanned system operation. The research and design of the …

Speaker Dependent Voice Recognition With Word-Tense Association And Part-Of-Speech Tagging, Theodore Philip King Ernst

Doctoral Dissertations and Master's Theses

Extensive Research has been conducted on speech recognition and Speaker Recognition over the past few decades. Speaker recognition deals with identifying the speaker from multiple speakers and the ability to filter out the voice of an individual from the background for computational understanding. The more commonly researched method, speech recognition, deals only with computational linguistics. This thesis deals with speaker recognition and natural language processing. The most common speaker recognition systems are Text-Dependent and identify the speaker after a key word/phrase is uttered. This thesis presents Text-Independent Speaker recognition systems that incorporate the collaborative effort and research of noise-filtering, Speech …

Run-Time Hev Engine-Generator Power-Speed Optimization For Fuel Consumption And Emissions Reduction, Chester Paul Rowe Ii

Doctoral Dissertations and Master's Theses

As fuel economy and emissions standards become more stringent, Plug-in Hybrid Electric Vehicles (PHEV) using series architectures are being increasingly explored. Due to the decoupling of the Internal Combustion Engine (ICE) from the road, the primary control challenge in this architecture is the optimization of an ICE control law. A run-time Genset speed controller is presented for use during the charge-sustaining mode in a Series PHEV to find the optimal operating parameters for a conventional diesel engine coupled to an electric generator in terms of minimized fuel consumption and emissions generation. On board vehicle sensors provide real time data to …

Development Of An Exteroceptive Sensor Suite On Unmanned Surface Vessels For Real-Time Classification Of Navigational Markers, Christopher Lloyd Kennedy

Doctoral Dissertations and Master's Theses

This thesis presents the development of an exteroceptive sensor suite for real-time detection and classification of navigational markers on Unmanned Surface Vessels. Three sensors were used to complete this task: a 3D LIDAR and two visible light cameras. First, all LIDAR points were transformed from the sensor’s reference frame to the local frame using a Kalman filter to estimate instantaneous vehicle pose. Next, objects were chosen from the LIDAR data to be classified using either Multivariate Gaussian or Parzen Window Classifiers. Both produce 96% accuracy or better, however, multivariate Gaussian ran considerably faster than the Parzen and was simpler to …

Inverse Volume-Of-Fluid Meshless Method For Efficient Non-Destructive Thermographic Evaluation, Hussein Awad Kurdi Saad

Doctoral Dissertations and Master's Theses

A novel computational tool based in the Localized Radial-basis Function (RBF) Collocation (LRC) Meshless method coupled with a Volume-of-Fluid (VoF) scheme capable of accurately and efficiently solving transient multi-dimensional heat conduction problems in composite and heterogeneous media is formulated and implemented. While the LRC Meshless method lends its inherent advantages of spectral convergence and ease of automation, the VoF scheme allows to effectively and efficiently simulate the location, size, and shape of cavities, voids, inclusions, defects, or de-attachments in the conducting media without the need to regenerate point distributions, boundaries, or interpolation matrices. To this end, the Inverse Geometric problem …

A Cfd Investigation Of The Hydrodynamic Characteristics Of Fluid Flow Through An Impeller And Multi-Objective Design Optimization Of A Centrifugal Pump, Mohammed Khammat Sagban

Doctoral Dissertations and Master's Theses

In this thesis, the first part is conducting an investigation of the hydrodynamic characteristics (pressure and velocity) of fluid flow (water) through an impeller of a centrifugal pump. To illustrate a one-dimensional model is used to identify an impeller of a GDM 10 x 12 HD centrifugal pump using Vista CPD design and BladeGen tool. A three-dimensional model is then built with a commercial software package ANSYS Blade Modeler. The structured mesh of the impeller blade is obtained by using TurboGrid system. The volute of the centrifugal pump is built in ANSYS geometry, and an unstructured mesh is accomplished by …

Modeling Hydrodynamic Stability Of Incline-Liquid Airblast Nozzle For Gas Turbine Combustion, Kevin Matiko

Doctoral Dissertations and Master's Theses

Fuel is a major cost item for civil transport airplanes. Minimizing fuel consumption of these crafts is a stream of economic opportunity and a stage for innovation, competition and exploration. Regardless of the fuel type, bio or crude oil based, the civil transport stakeholders would like to minimize fuel consumption of their airplanes. The mixing of fuel and air is a critical process for optimum combustion in gas turbine engines due to its high influence on the downstream combustion process. The need for minimizing fuel consumption coupled with the requirement for combustion systems to perform well at all flight conditions …

Investigation Of Traditional And Alternate Living Hinge Designs For Fused Deposition Modeling Additive Manufacturing Process, Cassandra Sue Gribbins

Doctoral Dissertations and Master's Theses

A manuscript-style thesis composed of three studies covered the application of living hinge designs in the additive manufacturing process of fused deposition modeling. Initial research included comparing numerical and analytical linear analyses on a traditional living hinge design. The second research consisted of tensile testing for the material properties of the Acrylonitrile Butadiene Styrene (ABS) used in fused deposition modeling (FDM) process by the MakerBot 2X as well as adjusting the traditional design to be printed. The third study explored alternate living hinge designs that utilize the geometric freedom provided by additive manufacturing to more evenly distribute stress across the …

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 …

Early Damage State Criterion From A Fault-Seeded Helicopter Gear Using Acoustic Emission And Neural Networks, Rudy L. Baum

Doctoral Dissertations and Master's Theses

In response to five failures since 2008 of the tail gearbox of multiple models of Sikorsky's H-60 helicopter, acoustic emission (AE) data collected from a rotating gearbox test stand at the Naval Air Station in Patuxtent River, MD, was used to monitor the initiation and propagation of a flaw from an electro-discharge machined (EDM) notch seeded on the face of a gear tooth. A period of testing was considered which spanned ~300,000 seconds or ~83 hours and culminates to a damage state such that a flaw has initiated on both ends of the EDM notch. AE data was analyzed for …

Energy Conservation By Intermittently Recirculating And Aerating An Aquaponics System With An Airlift, Bjorg Magnea Olafs

Doctoral Dissertations and Master's Theses

An airlift device providing aeration and circulation was designed to reduce electrical power requirements for aquaponics by eliminating the need for a water pump. The airlift performed better than predicted and achieved water flow rates of 10 L/min at 25 °C, in comparison to the theoretical design performance 2.65 L/min.

Koi (Cyprinus carpio) and sweet basil (Ocimum basilicum) were cultured for five weeks in two identical aquaponics systems. The system was located indoors and consisted of a fish tank, a sump tank, and a soil-free growth media bed under artificial lighting. The total water volume in each system was 230 …

Design Optimization Of A Composite Wing Box For High-Altitude Long-Endurance Aircraft, Philip T. Arévalo

Doctoral Dissertations and Master's Theses

A design optimization process is developed to define the wing box structure for High-Altitude Long-Endurance Aircraft (HALE). The goal of this study is to determine the best tradeoff between mass and rigidity of a HALE aircraft wing structure. A preliminary composite laminate structural design procedure is described which uses a NASTRAN-based Finite Element Analysis (FEA), and the Hierarchical Evolutionary Engineering Design System (HEEDS) MDO software to define a locus of acceptable, optimized wing box design definitions.

Fundamentals Of Machine Design And Manufacturing: Design Of A Compliant Winding Machine, Gazal Kaur Nagi

Doctoral Dissertations and Master's Theses

A Sparton Electronics Compliant Winding Machine has been redesigned for improved performance. Thorough study of the existing machine identified issues such as the inconsistent diameter and pitch of the compliant wind, outdated equipment, as well as safety and ergonomic issues. A comprehensive methodology for the design of the new machine is presented through using CAD systems and advanced analysis tools, such as Finite Element Analysis, and HEEDS. Resulting, the machine is successfully re-designed to fully control the diameter and the pitch of the product via servo motors and a control panel. The safety and ergonomic issues are effectively resolved by …

Design Of A Lean Manufacturing System For The Production Of Compliant Wind At Sparton Electronics, Arash Sabet-Rasekh

Doctoral Dissertations and Master's Theses

Increased demands in production numbers and higher expectations for product quality in today’s manufacturing industries have led to initiatives to improve processes through lean concepts. This study was conducted to demonstrate how Lean Manufacturing tools and techniques can be used to redesign a production system. The study focuses on the production of the compliant wind at Sparton Electronics. The compliant wind is one of the key components of a sonobuoy and its primary function is to isolate electrical components such as hydrophones from movement of the surface buoy. The goal of the redesign process is to increase production by focusing …

3d Simulation Of The Velodyne Hdl-32e Lidar Integrated With An Autonomous Marine Vehicle, Alecia A. Hurst

Doctoral Dissertations and Master's Theses

A 3D simulator is programmed for modeling the Velodyne HDL-32E LIDAR used on the WAM-V vehicle in the marine environment for obstacle detection. The model takes into account sensor integration, sensor error, and error correction. Theoretical analysis includes consideration of atmospheric refraction, time of flight error, UDP packet and timing, calibration parameter errors, depth spread error, field of view, accuracy, angular resolution, and points per second in the environment. The average distance error shows a variance of a 0.0127 m to 0.8128 m depending on the laser and the distance. Test results produce distance correction equations for each laser beam. …

Free-Piston Stirling Convertor Model Development, Validation, And Analysis For Space Power Systems, Jonathan F. Metscher

Doctoral Dissertations and Master's Theses

The Advanced Stirling Convertor (ASC) is a free-piston Stirling engine coupled with a linear alternator currently being under extended testing at the NASA Glenn Research Center (GRC). Using the Sage 1-D Stirling modeling software, a linear alternator model was developed using two separate methods and integrated with an existing ASC Stirling engine model. One used a simplified transducer method, while the other was developed from first principles. The combined models were tuned and validated against test data and then compared against each other. Both validated models are able to match test data within 7% or better. In addition, a MATLAB …

Modeling And Experimental Investigation Of Parabolic Trough Solar Collector, Mohanad Abdulazeez Abdulraheem Alfellag

Doctoral Dissertations and Master's Theses

In this thesis, a mathematical model is applied to study the performance of a parabolic trough solar collector (PTSC). The proposed model consists of three parts. The first part is a solar radiation model. In this section, the amount of solar radiation incident upon Earth is estimated using equations and relationships between the sun and the Earth. The second part is the optical model. This part has the ability to determine the optical efficiency of PTSC throughout the daytime. The last part is the thermal model. The aim of this section is to estimate the amount of energy collected by …

Decreasing The Power Consumption Of Hybrid Electric Vehicle Architectures, Domenic Leo Barsotti

Doctoral Dissertations and Master's Theses

This paper presents the challenges seen by current automotive manufacturers in their investigation of more fuel efficient vehicles. The two main areas for improvement are aerodynamics and passive cooling of electrical systems. Aerodynamics of an Ahmed body is investigated with a drag reduction system proposed utilizing slot jets at the rear of the bluff body . Two separate systems show a decrease in drag of 16 and 25%. The paper also investigates the use of a phase change material for a hybrid electric vehicles energy storage system cooling. Phase change materials take advantage of the latent heat of fusion to …

Design And Development Of Scalable Solar Powered Water Purification Systems For Developing Nations, Shavin Pinto

Doctoral Dissertations and Master's Theses

This thesis presents the design and development of solar powered water purification systems. The systems were designed to meet specific customer requirements that were established from the experiences gained after the installation of five water purification systems in various Haitian communities. The systems are scalable and are able to supply 10,000-20,000 gallons of clean drinking water per day. The design consists of 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 to 4-7 years before a new filter is …