Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Theses/Dissertations

University of Arkansas, Fayetteville

Discipline
Keyword
Publication Year
Publication
File Type

Articles 1711 - 1740 of 1741

Full-Text Articles in Engineering

Steganography In Ipv6, Barret Miller Dec 2008

Steganography In Ipv6, Barret Miller

Computer Science and Computer Engineering Undergraduate Honors Theses

Steganography is the process of hiding a secret message within another message such that it is difficult to detect the presence of the secret message. In other words, the existence of the secret message is hidden. A covert channel refers to the actual medium that is used to communicate the information such as a message, image, or file. This honors thesis uses steganography within the source address fields of Internet Protocol Version 6 (IPv6) packets to create a covert channel through which clandestine messages are passed from one party to another. A fully functional computer program was designed and written …

Go to article

A Study Of Switched-Capacitor Filters, Kacie Thomas Dec 2008

A Study Of Switched-Capacitor Filters, Kacie Thomas

Electrical Engineering Undergraduate Honors Theses

This paper presents the basic principles of the switched-capacitor circuit. In order to become more acquainted with the workings and design of filters and switched-capacitor filters specifically, an example filter was designed based on a set of parameters. It was constructed starting in the passive stage, then the active stage and finally the switched-capacitor filter was generated. All of these circuits were also simulated using SwitcherCAD and Saber. Then, a switched-capacitor filter designed by Auburn University was redesigned using the same process as the example circuit. It was also simulated in all three stages. The results from this design are …

Go to article

Key Factors In Tag Recognition For Rfid System, Nachiketa Das Aug 2008

Key Factors In Tag Recognition For Rfid System, Nachiketa Das

Computer Science and Computer Engineering Undergraduate Honors Theses

The research effort described here was a study of factors that affect the efficiency of a Radio Frequency Identification (RFID) system in reading a certain type of commonly used passive RFID tag ('Squiggle' by Alien Technologies). The two sets of experiments conducted under this study focus on two response variables namely: readability and read rate. The factors in focus are distance between antenna and tags, the number and combinations of tags simultaneously read by the system and position of the tags left or right of the center of the antenna. Two separate experimental setups as explained in the following sections …

Go to article

Design Of A Temperature Profiling System For Use In Thermal Processing Of Food Products, Linda Tarantino Aug 2008

Design Of A Temperature Profiling System For Use In Thermal Processing Of Food Products, Linda Tarantino

Biological and Agricultural Engineering Undergraduate Honors Theses

The purpose of this study was to develop a thermal inspection system on a full scale meat and poultry product line. The system must withstand the production and sanitation environments and adapt to the many different products and conditions present on a common product line. By using this device, food processors will be able to measure the internal temperature of the product during its entire cooking process. This will provide certainty to food processors if the product reached the required internal temperature by USDA standards as well as proof of their processes.

Go to article

Microwave Dielectroscopy Of Breast Tissue Phantoms In The 5.8-40 Ghz Range, Binh Tran Aug 2008

Microwave Dielectroscopy Of Breast Tissue Phantoms In The 5.8-40 Ghz Range, Binh Tran

Electrical Engineering Undergraduate Honors Theses

Based on the high contrast in dielectric properties between the low-water-contain sample and the high-water-content one, we can determine whether the tissue sample is cancerous or normal. In order to make the measurement repeatable and convenient, some phantom materials, which have the same dielectric properties of human tissues, have been prepared. These phantom tissues are made from gelatin, water with honey syrup and Sodium Chloride (NaCl). In this project, we are going to measure and compare the dielectric properties of different types of phantom tissues by using focused beam antennas. The purpose of this project is to perform a systematic …

Go to article

Service Oriented Transitive Closure Solution, Jonathan Baran Aug 2008

Service Oriented Transitive Closure Solution, Jonathan Baran

Computer Science and Computer Engineering Undergraduate Honors Theses

The goal of this project is a service based solution that utilizes parallel and distributed processing algorithms to solve the transitive closure problem for a large dataset. A dataset may be view conceptually as a table in a database, with a physical structure representing a file containing a sequence of records and fields. Two records are said to be transitively related if and only if they are directly related due to sharing of one or more specific fields, or a sequence may be made from one record to the other under the condition that all intermediate entries are related the …

Go to article

Kinetics Determination Of Soybean Oil Transesterification In The Design Of A Continuous Biodiesel Production Process, Irwin Jacob, Ed Clausen, Danielle Julie Carrier May 2008

Kinetics Determination Of Soybean Oil Transesterification In The Design Of A Continuous Biodiesel Production Process, Irwin Jacob, Ed Clausen, Danielle Julie Carrier

Biological and Agricultural Engineering Undergraduate Honors Theses

One-step batch transesterification consisting of three stepwise reversible reactions of pure soybean oil with methanol was conducted at two different mixing speeds (600 and 300 rpm) to produce soybean oil fatty acid methyl esters (biodiesel). In both batch reactions, sodium methoxide (1.09 wt% based on soybean oil) was used as the catalyst, the reaction temperature was 60oC, and the methanol-to-oil molar ratio was 6:1. The objectives were to determine and/or investigate: 1) the mechanism and order of the reaction, 2) the reaction rate constants, 3) the effect of changes in mixing intensity on the reaction rate, 4) the comparison of …

Go to article

Location-Based Hashing For Querying And Searching, Felix Ching May 2008

Location-Based Hashing For Querying And Searching, Felix Ching

Computer Science and Computer Engineering Undergraduate Honors Theses

The rapidly growing information technology in modern days demands an efficient searching scheme to search for desired data. Locality Sensitive Hashing (LSH) is a method for searching similar data in a database. LSH achieves high accuracy and precision for locating desired data, but consumes a significant amount of memory and time. Based on LSH, this thesis presents two novel schemes for efficient and accurate data searching: Locality Sensitive Hashing-SmithWaterman (LSH-SmithWaterman) and Secure Min-wise Locality Sensitive Hashing (SMLSH). Both methods dramatically reduce the memory and time consumption and exhibit high accuracy in data searching. Simulation results demonstrate the efficiency of the …

Go to article

Dna Comparison Chip: Circuit Design And Evaluation, Tushar Bajaj May 2008

Dna Comparison Chip: Circuit Design And Evaluation, Tushar Bajaj

Electrical Engineering Undergraduate Honors Theses

The purpose of this project was to: First, design a microchip that is capable of comparing strings of DNA sequences. Second, evaluate the functioning of such a microchip and how it can implemented in various real world applications. Physically, this microchip will act as an attachment to any computer. The computer will send two strings of DNA sequences-one library string and one pattern string-and the chip will output the number of matches that exist between the two strings (at a given position of the pattern string with respect to the library string). The circuit design is based on a 600 …

Go to article

A Timer Module For An 8051 Microcontroller, Troy England May 2008

A Timer Module For An 8051 Microcontroller, Troy England

Electrical Engineering Undergraduate Honors Theses

A timer module for an 8051 Microcontroller is designed from the ground up. It could potentially be integrated into a larger 8051 for use in lunar and Martian missions. It follows through a synchronous digital design flow from HDL code through layout verification. The timer shows functionality at 100MHz with some minor glitches.

Go to article

Measurement Of Absolute Argon Excited State Populations And Electron Energy Distribution Functions In An Ar-A-Si Plasma, Katherine Herring May 2008

Measurement Of Absolute Argon Excited State Populations And Electron Energy Distribution Functions In An Ar-A-Si Plasma, Katherine Herring

Electrical Engineering Undergraduate Honors Theses

Deposition systems utilizing plasma are used for a variety of tasks, including tool coatings and creating thin-film materials. In order to have repeatable results, the internal conditions of a plasma chamber need to be known. This project centered on the use of data from optical emissions and a Langmuir probe from an argon plasma amorphous silicon depositing system. An electron energy distribution function (EEDF) was obtained from manipulation of the Langmuir probe data. This EEDF was then input to an argon collisional-radiative model (CRM) to obtain the electron population of the 4p level of the argon plasma. Through an absolute …

Go to article

Aquatic Bacteria Removal Using Carbon Nanotubes, Suvish Melanta May 2008

Aquatic Bacteria Removal Using Carbon Nanotubes, Suvish Melanta

Biological and Agricultural Engineering Undergraduate Honors Theses

The purpose of this project is to explore the functionality of carbon nanotubes as a bacterial removal method, specifically towards water-borne bacterial pathogens in wastewater by utilizing its unique magnetic and bacteria-binding properties. The general protocol set for this research follows five steps: 1) Preparation of wastewater media, 2) preparation of CNT culture, 3) preparation of reaction mixture with CNTs for bacterial binding, 4) magnetic separation of bacteria-bound-CNT clusters and, 5) assessment of supernatant. The CNTs effectively removed bacterial contaminants in the wastewater (10%, v/v) after the sand filtration process from the Paul R. Noland Wastewater Facility at Fayetteville, Arkansas. …

Go to article

A Study Of Inhomogeneity Effects On Packed High Performance Liquid Chromatography Columns, Tyler House May 2008

A Study Of Inhomogeneity Effects On Packed High Performance Liquid Chromatography Columns, Tyler House

Chemical Engineering Undergraduate Honors Theses

The packing quality of a High Performance Liquid Chromatography column has significant impact on the resulting separations. In practice, problems in a packing occur through normal usage of a column. Resulting chromatograms from inhomogeneities exhibit varying problems such as extreme tailing and double peaks. Early detection of such problems is critical to fixing problems before their effect harms efficiency, but a fully developed theory of how inhomogeneities affect separations does not exist. The purpose of this work was to experimentally characterize HPLC column inhomogeneities and to begin preliminary simulations of HPLC columns with the computer simulation package STAR-CD. To do …

Go to article

Visualization Of An Approach To Data Clustering, Marisabel Guevara May 2008

Visualization Of An Approach To Data Clustering, Marisabel Guevara

Computer Science and Computer Engineering Undergraduate Honors Theses

Using visualization and clustering goals as guidelines, this thesis explores a graphic implementation of a data clustering technique that repositions vertices by applying physical laws of charges and springs to the components of the graph. The resulting visualizations are evidence of the success of the approach as well as of the data sets that lend themselves to a clustering routine. Due to the visual product of the implementation, the algorithm is most useful as an aid in understanding the grouping pattern of a data set. Either for a rapid analysis or to assist in presentation, the visual result of the …

Go to article

Multiuav2 Agent Swarming For Distributed Atr Simulation, Kyle White May 2008

Multiuav2 Agent Swarming For Distributed Atr Simulation, Kyle White

Computer Science and Computer Engineering Undergraduate Honors Theses

Traditional automatic target recognition (ATR) is performed by unmanned aerial vehicles (UAVs) depending on a central control tower to provide the high level organization of the system. The UAVs fly through a region of interest to identify targets and relay all communication through a central control tower. The centralized approach to ATR has limited fault-tolerance, scalability with regards to the number of UAVs, and susceptibility to malicious attacks on the central tower [2]. A swarm-driven alternative [1] is extended with a communication control scheme to address fault-tolerance and scalability while utilizing the higher onboard processing power now available for UAVs …

Go to article

Pitch Correction On The Human Voice, Suzanne Ownbey May 2008

Pitch Correction On The Human Voice, Suzanne Ownbey

Computer Science and Computer Engineering Undergraduate Honors Theses

No abstract provided.

Go to article

Developing Subgrade Inputs For Mechanistic-Empirical Pavement Design, Meagan Berlau May 2008

Developing Subgrade Inputs For Mechanistic-Empirical Pavement Design, Meagan Berlau

Computer Science and Computer Engineering Undergraduate Honors Theses

No abstract provided.

Go to article

Computational Modeling Of Oxidative Stress: An Analysis Of Nad (P)H Effects On Nitric Oxide And Superoxide During Hypertension, Aaron Strobel May 2008

Computational Modeling Of Oxidative Stress: An Analysis Of Nad (P)H Effects On Nitric Oxide And Superoxide During Hypertension, Aaron Strobel

Biological and Agricultural Engineering Undergraduate Honors Theses

Nitric oxide (NO) is inactivated in the human body when exposed to superoxide (O2 -). This reaction forms peroxynitrite (ONOO-). Superoxide is produced in the cardiac system by several different ways, including NAD(P)H oxidase. Superoxide dismutase (SOD) breaks down superoxide into oxygen and hydrogen peroxide. This prevents superoxide from reacting with nitric oxide and allows normal function to take place. Superoxide and peroxynitrite are main contributors to vascular disease in the human body, in particular hypertension. Experiments have shown that there was an increase of superoxide production in spontaneously hypertensive rats (SHR) vs. age-matched Wistar Kyoto rats (WKY) that were …

Go to article

Optical Properties Of Colloidal Core/Shell Nanocrystals, Abhishek Joshi May 2008

Optical Properties Of Colloidal Core/Shell Nanocrystals, Abhishek Joshi

Electrical Engineering Undergraduate Honors Theses

Recently, colloidal core/shell nanocrystals have found use in several applications such as solar cells, light emitting diodes, fluorescent dies, etc. In this thesis, optical properties of colloidal CdSe/ZnS core/shell nanocrystals were studied. The samples were prepared such that the nanocrystals were embedded in a UV curable resin. Once the samples were cured, they were placed in different spectrophotometers to measure the absorbance and the photoluminescence (PL) spectrum. The effect on the absorbance and PL spectra was investigated by using nanocrystal samples of different quantum dot sizes and by changing the temperature of the samples. It was found that the energy …

Go to article

Restart Capabilities Of Hybrid Rocket Motor Utilizing Gaseous Propane And Oxygen Injection System, Joseph Gracy May 2008

Restart Capabilities Of Hybrid Rocket Motor Utilizing Gaseous Propane And Oxygen Injection System, Joseph Gracy

Mechanical Engineering Undergraduate Honors Theses

Hybrid rockets have become an increasingly popular application in professional and amateur rocketry for their outstanding performance and reliability. An issue pressing the marketability and functionality of these rockets is the ability to restart with an exclusive system after primary ignition. Research and development of a system that can be used reliably in either application to achieve restart under various conditions has been made recently using dual injection of GOX and C3H8 using a 200kV ignition system while implementing a polymethylmethacrylate (PMMA) formable polymer as primary fuel. The system used a manual valve arrangement for control. The design features most …

Go to article

Development Of Miniature Hybrid Rockets For Orbital Upkeep And Transfer Applications In Nano/Pico-Satellites, Derek Willingham May 2008

Development Of Miniature Hybrid Rockets For Orbital Upkeep And Transfer Applications In Nano/Pico-Satellites, Derek Willingham

Mechanical Engineering Undergraduate Honors Theses

This research has developed and constructed a successful miniature hybrid rocket test assembly for research into hybrid rocket scaling issues. It is hoped that such systems will find eventual integration into small satellites. The test assembly houses 3" fuel grains and provides an inlet for gaseous oxidizer. Although far from complete, preliminary data were taken with PMMA and GOx and some useful conclusions were drawn that will benefit future research into this topic. Fuel grains with combustion chambers whose diameters range from 1/16" to 3/8" were tested at different flow rates and thrust data gathered. Maximum flow information was gathered …

Go to article

The Effect Of Water Extracted Silibinin On Reactive Oxygen Species (Ros) Production Of Macrophages, Julie Abbott, Sunny Wallace, Ed Clausen, Danielle Carrier May 2008

The Effect Of Water Extracted Silibinin On Reactive Oxygen Species (Ros) Production Of Macrophages, Julie Abbott, Sunny Wallace, Ed Clausen, Danielle Carrier

Biological and Agricultural Engineering Undergraduate Honors Theses

The world is actively looking for technology to produce sustainable liquid fuels to replace our reliance on petroleum-based fuels. Biomass can be converted either through the thermochemical or saccharification platforms into fuels such as ethanol or butanol. In addition to converting the biomass into liquid fuels, valuable phytochemicals can be extracted prior, during, or after the conversion. Extracting useful phytochemicals, as a part of the overall conversion of biomass to fuels, is included in the concept of the biobased biorefinery. However, the key to effectively and economically extract phytochemicals from biomass is the ability to couple the extraction to the …

Go to article

Simulation Of Multicultural Factors In Terrorism Networks, Jared Townsley May 2008

Simulation Of Multicultural Factors In Terrorism Networks, Jared Townsley

Industrial Engineering Undergraduate Honors Theses

As globalization extends its influence to the far corners of the world, rapid developments and changes are taking place economically, socially, and environmentally. Cultural differences between and within organizations have become significant during the past few years as politics and marketplaces expand globally to include multiple nationalities, beliefs, and value systems. Unfortunately, terrorism has also felt the effects of globalization as organizations such as Al-Qaeda seek to expand their influence worldwide. Although a considerable amount of research has been conducted to identify key cultural factors that play major roles within organizations, simulation models that attempt to quantify cultural effects are …

Go to article

A Comparison Of Nondestructive Testing Backcalculation Techniques For Rigid And Flexible Pavements, Trenton Ellis May 2008

A Comparison Of Nondestructive Testing Backcalculation Techniques For Rigid And Flexible Pavements, Trenton Ellis

Civil Engineering Undergraduate Honors Theses

In designing new pavements, engineers rely on many different measures to characterize the average traffic, climate and soil conditions of the region. Of those, soil conditions are the most elusive, but are also the most crucial for designing a pavement of proper thickness and stiffness. This problem is compounded when the design is for an overlay instead of a new pavement. For overlay designs, engineers require a quantitative characterization of the strength of the existing pavement as well as the underlying soil. Especially for new Mechanistic-Empirical design procedures, direct measures and/or estimates of pavement stiffness are essential inputs. A variety …

Go to article

Benefits Of Leed Designs In Arkansas K-12 Schools, Philip Thrift May 2008

Benefits Of Leed Designs In Arkansas K-12 Schools, Philip Thrift

Mechanical Engineering Undergraduate Honors Theses

This paper provides and evaluation of an existing LEED certified sustainable green building for energy-efficiency, environmental impact, economic value, and occupant health. The new Bethel Middle School located in Bryant, Arkansas was the first LEED (Leadership in Energy and Environmental Design) certified public school building in the state. Based on actual building specifications and validated with the first year's utility bills, a simulation model was used to evaluate various design aspects of the school building. The building's baseline energy usage was compared with numerous energy and environmental scenarios. Results include both environmental and economic assessments. Overall, the study found that …

Go to article

Development Of Low Temperature Alpha Alumina Coatings By Ac Magnetron Sputtering, Andrew Cloud May 2008

Development Of Low Temperature Alpha Alumina Coatings By Ac Magnetron Sputtering, Andrew Cloud

Mechanical Engineering Undergraduate Honors Theses

Alpha-phase aluminum oxide thin films were created using an Isoflux ICM-10 dual target inverted cylindrical magnetron sputtering system using mid-frequency AC power supplies. Alpha alumina films were deposited at a magnetron power of 6 kW, 50% oxygen partial pressure by volume, and -35 V DC bias. Film thickness, substrate material, and position and orientation within the deposition chamber were varied. To ensure the deposition conditions are suitable for alloys, the substrate temperature was measured using temperature indicating liquids. The experimental results, supported by Explicit Euler numerical analysis, revealed a steady state temperature of ~480°C at 6kW. Transmission electron microscopy (TEM) …

Go to article

A Review Of Variable Valve Timing Devices, Paul Shelton May 2008

A Review Of Variable Valve Timing Devices, Paul Shelton

Mechanical Engineering Undergraduate Honors Theses

Variable valve timing (VVT) has evolved from simple, manual controlled engine management to automatic, electronic works of engineering. Starting from the need for more power and extending into fuel efficiency and low emissions, VVT has evolved from the constant changing of needs. This paper summarizes various devices used to control the timing of valves from the early 1920s up until 2007.

Go to article

The Development Of Regional Regression Equations For Flood Flow Estimates Of Ungauged Streams In The State Of Arkansas, Stephen Mccall Dec 2007

The Development Of Regional Regression Equations For Flood Flow Estimates Of Ungauged Streams In The State Of Arkansas, Stephen Mccall

Civil Engineering Undergraduate Honors Theses

No abstract provided.

Go to article

Validation Of Adaptive Aeroelastic Finite Element Program For Two Dimensional Flow Past A Suspension Bridge Girder Section Using Unstructured Grids., Shanique Murray Dec 2007

Validation Of Adaptive Aeroelastic Finite Element Program For Two Dimensional Flow Past A Suspension Bridge Girder Section Using Unstructured Grids., Shanique Murray

Civil Engineering Undergraduate Honors Theses

No abstract provided.

Go to article

Atomic Force Microscope Imaging Of Dna And Multi Walled Carbon Nanotubes, Jacob Hohnbaum May 2007

Atomic Force Microscope Imaging Of Dna And Multi Walled Carbon Nanotubes, Jacob Hohnbaum

Mechanical Engineering Undergraduate Honors Theses

The Micro and Nano System Laboratory at the University of Arkansas currently is equipped with an Atomic Force Microscope (AFM). This device can be used to measure objects with resolution on the nanometer scale, but there are a number of technical difficulties in performing scans of carbon nanotubes and DNA. The goal of this research is to successfully perform scans on both carbon nanotubes and DNA and to also establish laboratory processing protocols to re-perform such scans in the future. Previous works performed by other researchers in the laboratory provided basic protocols with which to begin the present research. These …

Go to article

First Prev Next Last