Digital Commons Network^™

“A Hybrid Method For Selecting Scheduling Schemes In A Manufacturing Environment, Panagiotis Martinis

Masters Theses

Scheduling is defined as the allocation of resources, machinery or people, to accomplish specific tasks over a certain time-slot. Scheduling is one of the most important functions within an industrial system. Throughout a successful scheduling policy, the utilization of resources is optimized and goods are produced on time to meet demand, the basic elements that contribute to the welfare of the business. Simultaneously, scheduling has always been one of the most difficult and challenging tasks given the dynamic nature of the industrial environment. Under certain circumstances, it is often required revision of existing schedules. The action of revising existing schedules …

Design Of A Wide-Swing Cascode Beta Multiplier Current Reference, Bradley David Miser

Masters Theses

This thesis presents a study of the design of a wide-swing, cascode β multiplier current reference to be used as a biasing circuit. The current reference has been fabricated in a 0.5mm CMOS technology. First, a review of wide-swing cascode current mirrors and current-source self-biasing is covered. Then, the process of designing a current reference that is both wide-swing and has high output resistance is presented. Simulation and measurement results from the current reference are detailed. Improvements upon the current reference are also suggested.

A Simulation Based Approach For Determining Maintenance Strategies, Vasanth Murthi

Masters Theses

Manufacturing organizations are continuously in the mode of identifying and implementing mechanisms to achieve a competitive edge. To this point manufacturers have recognized the critical role of equipment in the productivity of manufacturing operations. With the current trend of manufacturers attempting to lean out their production processes, primary and auxiliary equipment have become even more important to manufacturers as measured by productivity, quality, delivery, and cost metrics. As a result of the focus on lean manufacturing, maintenance management has found a new vigor and purpose to increase equipment capacity and capability. However, the most proactive maintenance strategy is not always …

Performance Of Bit Error Rate And Power Spectral Density Of Ultra Wideband With Time Hopping Sequences., Joseph Martin Peek

Masters Theses

This thesis focuses on several modulation methods for an ultra wideband (UWB) signal. These methods are pulse position modulation (PPM), binary phase shift keying (BPSK), on/off key shifting (OOK), and pulse amplitude modulation (PAM). In addition, time hopping is considered for these modulation schemes, where the capacity per time frame of time hopping PPM is studied using different spreading ratios. This thesis proves that with the addition of time hopping to all types of modulated UWB signals, the performance of power spectral density improves in all aspects, despite the increase of data per time frame. Note that despite the increase …

Modeling Of Corrugated Graphite Foam Heat Exchangers, Timothy Henry Norton Jr.

Masters Theses

A new manufacturing process was recently developed by the Oak Ridge National Laboratory for the production of graphite foam. The high thermal conductivity and heat transfer area of the foam make it desirable for thermal management applications such as compact heat exchangers. The heat transfer capabilities of the foam are especially useful in internal forced convection applications. However, due to the very low permeability of graphite foam, pressure-drop is very high compared to other porous media, and pressuredrop reduction schemes are necessary to ensure its practical application. Pressure-drop reduction can be achieved through the strategic machining of graphite foam into …

Parameter Study On Topology Optimization Of Constrained Layer Damping Treatments, Rohan Vinay Pai

Masters Theses

This study investigates the optimal topology of a constrained layer damping treatment involving viscoelastic materials under a static load for different boundary conditions in order to maximize the damping loss factor for the first vibrating mode of the base structure. Different parameter studies are carried out for the two boundary conditions and conclusions are drawn based on the loss factor results and the novel topologies that emerge from these optimization results. The novel topologies are then used to interpret shapes that are more reasonable to manufacture. Tremendous improvement in the loss factor (up to 1250%) is obtained by topology optimization …

An Analysis Of Liquid Aluminum Sulfate (Alum) Use In Broiler Production Houses To Control In-House Ammonia (Nh3) Concentrations And Naturally-Occurring Salmonella And Campylobacter; The Development Of An Nh3 Emission Factor For A Typical Tennessee Broiler House., Kenneth A. Armstrong

Masters Theses

No abstract provided.

Stream Water Quality Modeling In The Great Smoky Mountains National Park., Thomas Wayne Barnett

Masters Theses

The purpose of this study was to examine water quality in the acid-impacted Great Smoky Mountains National Park (GRSM). Water samples have been collected roughly quarterly at ninety sampling sites throughout the Park. These samples were analyzed for pH, acid neutralizing capacity (ANC), conductivity, major cations, and major anions. This thesis utilizes data from samples collected from October, 1993 to November, 2002.

The trout fisheries of the GRSM are considered some of the best in the eastern United States. However, fisheries biologists at the GRSM believe that some of the streams that once supported trout populations twenty or thirty years …

Comparison Of Microbial Cell Densities And Treatment Performance In Nitrifying Activated Sludge Reactors, Janalyn Rae Brown

Masters Theses

A thorough understanding of microbial dynamics in activated sludge treatment is currently unrealized due, in part, to quantitative techniques that rely on culture-dependent methods. The bias inherent with cultivation techniques may result in isolates that do not necessarily represent those dominant in the system evaluated. In situ analysis of microorganisms functioning in wastewater reactors will provide a greater understanding of how particular groups of organisms, such as nitrifiers, are impacted by system fluctuations. This information is vital for improved process design and control. The overall goal of this research was to investigate the use of the real-time polymerase chain reaction …

A Preliminary Study Of The Effects Of Exposure To A One Atmosphere Uniform Glow Discharge Plasma (Oaugdptm) On The Surface Energy And Strength Of Meltblown And Nanofiber Fabrics, Weiwei Chen

Masters Theses

Electrohydrodynamic (EHD) methods have recently been developed to electrospin nano-scale non-woven webs and to improve their properties by exposure to the One Atmosphere Uniform Glow Discharge Plasma (OAUGDPä), as a collaborative effort by the UT Plasma Sciences Laboratory and the UT Textiles and Nonwovens Development Center (TANDEC).

Nanofiber webs are made by the electrospinning (ES) process, which uses the electrostatic force to spin fibers from a polymer solution or melt. Digitized SEM images show that the fiber diameters range from 10 nm to several microns. Such nanofiber fabrics have a significantly higher tensile strength than meltblown (MB) webs of the …

The Effects Of Temperature And Solids Retention Time On Activated Sludge Treatment Performance, Jack Mcclendon Carley

Masters Theses

A bench-scale treatment system with external clarifier was used to determine the effects of solids retention time (SRT) and temperature on treatment performance while simulating the full scale activated sludge process. Four bench-scale reactors, operating at SRTs of 20, 10, 5 and 2 days, were fed settled municipal wastewater collected after primary clarification from the Kuwahee wastewater treatment plant in Knoxville, TN. Three operational temperatures were investigated during this study, 22oC, 12oC and 7oC. The order and duration of operation at each temperature was first 22oC for 61 days, next 7oC for 47 days and lastly 12oC for 105 days. …

Analysis And Design Of A Gear Shifting Mechanism For Transmission Based Actuators, Kalyana Bhargava Ganti

Masters Theses

The fundamental idea of Transmission Based Actuators (TBA) is to incorporate a multi-speed transmission to spread a servomotor’s torque speed characteristics across a wider output speed range. TBA uses multi-speed transmissions such that heavy, high-torque motors can be traded for high-speed, reduced mass motor-transmission combinations. TBA design consists of a D.C. Brushless motor, discrete gear transmission and a fixed reduction. Of these, the fundamental to the proof of principle of TBA is the design of the discrete gear transmission.

Basically the DVT is a three-speed gearbox consisting of 3 sets of epicyclic gears. Every planetary gear set is a two-degree …

Generic Transportation Model Applied To Catalytic Steam Gasification Of Poultry Litter And To Rotary Kiln Incineration Of Shredded Tires, Jennifer Fuller English

Masters Theses

Many environmental issues are related to the disposal of both poultry litter and used tires. In an effort to provide a more environmentally friendly alternative to disposal of these substances, work has been done previously at UTSI in the areas of catalytic steam gasification of poultry litter and rotary kiln incineration of shredded tires. The scope of this research is to develop a transportation model that can be used for either of these processes. The model will be used to determine their economic feasibility under changing conditions including traveling distance, feed rate, and price fluctuations in the sales price of …

Modernization Of The United States Naval Test Pilot School's Helicopter Fleet - Replacement Of The Th-6b And The Oh-58c With The Bell 407 Helicopter, Steven R. Girard

Masters Theses

The United States Naval Test Pilot School (USNTPS) experienced a helicopter mishap on 05 August 2001. The USNTPS Commanding Officer believed that this mishap occurred in large part due to the extremely high workload being placed onto both the school’s students and instructors. As a result of this belief, the USNTPS Commanding Officer ordered his staff to implement the following three orders:

1. Immediately reduce syllabus exercises by 10%.
2. Begin to revamp each syllabus in order to reduce the student workload by 25%.
3. Review syllabus aircraft requirements and recommend one aircraft that can be eliminated from the syllabus inventory without degradation …

Theoretical And Experimental Study Of Degradation Monitoring Of Steam Generators And Heat Exchangers, Xuedong Huang

Masters Theses

The objective of this research is focused on the modeling, analysis, and experimental study of steam generator and heat exchanger degradation monitoring and fault diagnosis. Experimental and analytical studies of tube fouling are performed and the system-level degradations are monitored using data-driven modeling of heat exchanger measurements. Initially, a comprehensive literature study was made on the steam generator and heat exchanger degradation types and mechanisms, including fouling and corrosion.

Based on the mass balance, energy balance, and momentum balance and the moving-boundary method, a multi-node SIMULINK model of a U-tube steam generator (UTSG) has been developed so as to simulate …

Process - Structure – Property Relationships Of Electrospun Nano Fibers, Sudhakar Jagannathan

Masters Theses

Electrospinning is a process by which fibers with diameters as small as 15 nanometers are produced when a polymer solution is accelerated from a capillary towards a grounded target by an electric field. An investigation on the electrospinning process and the effect of its process variables on orientation, crystallinity, microstructure and mechanical properties of the fibers produced are made. Nylon 6, nylon 66 fibers and their blends from a solution of formic acid were produced on a stationary copper target as well as on a metal disc rotating at discrete variable speeds. The solution concentration of the polymers, distance of …

Limestone Contactors As A Corrosion Control Technology For Small Public Water Systems: An Educational Module For Drinking Water Professionals, Azarina Mohd Jalil

Masters Theses

This thesis includes a review of literature of the limestone contactors technology for small water systems and discusses the process and methodology involved in developing the educational module on limestone contactors. It includes most of the narrative texts presented in the module. Both this thesis and the module are intended to be used as an educational tool by small public water system operators, owners, regulators, and engineers of limestone contactors as a corrosion control method to meet the lead and copper action level stated in the U.S. EPA’s Lead and Copper Rule. This module includes the description of the processes …

Effect Of Loading Frequency On Intervertebral Disc Cells., Kristen Nicole Loveless

Masters Theses

Cells of the intervertebral disc have a limited capacity for matrix repair and may contribute to the onset and progression of degenerative disc changes. Disc degeneration contributes to declining nutrition, loss of viable cells, cell senescence, post-translational modification of matrix proteins, accumulation of degraded matrix molecules, and fatigue failure of the matrix. During daily activities intervertebral discs are exposed to oscillatory hydrostatic loads. It is known that dynamic loads with critical frequencies close to that of the human spine resonant frequency (4-8 Hz) have a destructive effect on disc tissue properties. Whether this destructive effect is purely mechanical due to …

Modeling Of Circulation Zone And Shear Layers In Coaxial Injectors, Clayton Andrew White

Masters Theses

Gaseous/gaseous hydrogen oxygen shear coaxial injectors were modeled to investigate grid parameters affecting solution and to determine if a steady state solution might exist if only one circulation zone was present. The General Equation Mesh Solver (GEMS), which implements the Reynolds Averaged Navier-Stokes equations with the k-ω turbulence model, was used to conduct the study. The Gambit grid generator was used to construct computational grids. Different grids were compared in a search for the optimum configuration while residual levels were monitored in search of a steady state solution.

Virtual And Augmented Reality Simulation Of Chattanooga Creek, Sirisha Vadlamudi

Masters Theses

Virtual reality involves reproducing all the details of a physical object or environment that has to be simulated in virtual space. Augmented reality is the mixing of computer-generated information with the user’s view of the real world. Augmented reality is an alternative for virtual reality. This thesis presents the interactive virtual reality simulation and augmented reality simulation of Chattanooga Creek in Chattanooga, TN. The augmented reality part involves implementation of the basic concept of augmenting the virtual graphics to the real world.

A Study Of The Temperature Correction Methods For Reciprocating Engine Flight Testing Under Non Standard Conditions, Juan Carlos Valer

Masters Theses

Federal Aviation Regulations require aircraft reciprocating engines to comply with temperature limits under pre-defined hot-day conditions. When the test is conducted on other than those conditions, the Regulations provide equations to convert the temperature registered into values considered to be corresponding to a hot-day scenario.

It is known by the flight test community that those equations over compensate for flying in non-hot day conditions. As a consequence of that, an aircraft that could be certified under hot day conditions may not be certifiable in a colder atmosphere.

This thesis confirmed that the Piper Saratoga complies with the regulations on cooling …

Silicon-On-Insulator Power Management Integrated Circuit For Thin-Film Solid-State Lithium-Ion Micro-Batteries, Jeremy Ross Jackson

Masters Theses

This thesis presents the design and implementation of a power management integrated circuit (IC) that is capable of both current and voltage charging thin-film, solid-state, lithium-ion micro-batteries. The power management system has been fabricated using a single-poly, 0.35-ìm, partially-depleted, silicon-on-insulator process (PD-SOI). The system contains a temperature stable current charger (current generator and a 4-bit current-mode DAC), a regulated voltage supply (voltage amplifier), and a voltage monitoring circuit (2-bit flash ADC). Experimental results of the first version of the power management system show proper functionality was obtained. The current charger produced a 2% worst-case variation in output current over the …

Investigation Of Compound Micro Cantilever For Imaging And Identifying Micro/Nano Particulates, Ramanathan Narayanan

Masters Theses

Atomic Force Microscopes (AFM) are typically used to image surfaces along with small particulates that may be deposited on the surface. Surface imaging can be made down to the atomic level but usually it is conducted at the nano and micro scales. It is highly desirable to identify the constituency of particulates on the surface and if possible determine the chemical and physical identity of particulates. The objective of the research presented in this thesis is to establish the feasibility of using dual micro cantilevers to determine the physical constituency of nano particles deposited to the micro surface. The goal …

Silicon Carbide Gto Thyristor Loss Model For Hvdc Application, Madhu Sudhan Chinthavali

Masters Theses

With the increase in use of power electronics in transmission and distribution applications there is a growing demand for cost effective and highly efficient converters. Most of the utility applications have power electronics integrated in the system to improve the efficiency and functionality of the existing system. The development of semiconductor devices is vital for the growth of power electronic systems. Modern technologies like voltage source converter (VSC) based HVDC transmission has been made possible with the advent of power semiconductor devices like IGBT and GTO thyristor with their high power handling capability. Various material limitations of silicon power semiconductor …

Instrumented Self-Propelled Sprayer To Determine Dynamic Boom Effects On Droplet Application Uniformity, Hong Young Jeon

Masters Theses

A self-propelled sprayer with a 27-m boom was instrumented to measure inadvertent boom movement and acceleration during field operation to quantity application uniformity. The instrumentation system was developed to monitor boom end heights, accelerations, and sprayer longitudinal position along a track. Acceleration measures included longitudinal (x), vertical (y), and transverse (z) components at the sprayer vehicle rear, boom center, and at each boom end. A PC-based data acquisition system polled sensors at 2.5 kHz. Software-implemented, 2^nd-order Butterworth band pass (0.1 to 15 Hz) filtering of raw data reduced signal noise. Y-accelerations at the boom center ranged from 1.5 …

A Design Study Of A Proposed Four-Seat, Amateur-Built Airplane, D. Andrew Moore

Masters Theses

An airplane configuration suitable for construction by an amateur builder without the need for complex factory fixtures and tooling has been developed. The proposed high-wing configuration is intended to carry a 600 LB payload of up to 4 passengers arranged in 2 rows of side-by-side accommodations at a design cruise speed of 145 kts. It has been shown that the cantilevered wing components of the low-wing, 2-seat Mustang II kit airplane are ideally suited for the proposed airplane when properly matched with strut braced inboard wing panels. The structural implications of optimally sized ailerons on the baseline Mustang II wing …

Approaches For Matlab Applications Acceleration Using High Performance Reconfigurable Computers, Saumil Girish Merchant

Masters Theses

A lot of raw computing power is needed in many scientific computing applications and simulations. MATLAB®† is one of the popular choices as a language for technical computing. Presented here are approaches for MATLAB based applications acceleration using High Performance Reconfigurable Computing (HPRC) machines. Typically, these are a cluster of Von Neumann architecture based systems with none or more FPGA reconfigurable boards. As a case study, an Image Correlation Algorithm has been ported on this architecture platform. As a second case study, the recursive training process in an Artificial Neural Network (ANN) to realize an optimum network has been accelerated, …

Proposed Ifr Air Ambulance Coverage For Middle And East Tennessee, James Christopher Mills

Masters Theses

Rural areas do not receive the same emergency medical services as metropolitan and suburban areas due to their remote locations. In the event of a life-threatening medical emergency, citizens in rural areas cannot be transported to a level-one trauma center within the critical Golden Hour. The Golden Hour is the hour during which the mortality rate can be reduced by 50% if a patient can reach a trauma center. The inability of helicopter EMS operations to fly in poor weather lessens a patient’s chances for surviving a medical emergency. Helicopter air ambulance operations enable hospitals to provide comparable service to …

Development And Verification Of Parameterized Digital Signal Processing Macros For Microelectronic Systems, Adam Robert Miller

Masters Theses

Digital system design is a broad field that is growing every day. As technology grows, the complexity of systems grows also, which leads to longer design times. A Design-for-reuse policy can decrease design time by building flexibility into designs as they are created. By creating parameterized macros, they are more likely to be reused. Verifying the capabilities of macros is also important, and testing should be incorporated into each step of the design process. In this thesis, designing parameterized macros is discussed, with a Complex Fast Fourier Transform presented as an example of a complex algorithm, and three different Rounder …

A Conceptual Design Of A General Aviation Hands-On-Throttle And Stick (Hotas) System., Mark N. Callender

Masters Theses

In this project the concept of Hands-on-Throttle and Stick (HOTAS) was applied to a general aviation (GA) aircraft. HOTAS had seen limited use in GA aircraft, but nothing that would compare to its use in military or commercial aircraft. The purpose of incorporating HOTAS was to give the pilot the ability to quickly and efficiently operate specific functions of the aircraft’s avionics units without having to remove his/her hands from the stick (or control wheel) or throttle. This project followed the systems engineering approach to accomplish the conceptual design of the GA HOTAS system. Two representative GA aircraft were chosen …