Engineering Commons^™

An Experimental Investigation Of Higher Order Mode Suppression In Tem Cells, Shaowei Deng, David Pommerenke, Todd H. Hubing, Dongshik Shin

Electrical and Computer Engineering Faculty Research & Creative Works

Transverse electromagnetic (TEM) cells can be used to evaluate the electric and magnetic fields coupling from integrated circuits (ICs). The propagation and reflection of higher order modes in the cells limits the bandwidth of TEM cells. This paper investigates several methods for suppressing higher order modes in TEM cells in order to extend the applicable frequency range without changing the test topology. Numerical models and measurements of a modified TEM cell demonstrate how higher order mode suppression techniques can extend the useful frequency range of a TEM cell for IC measurements from 1 to 2.5 GHz.

Clustering Of High-Dimensional Gene Expression Data With Feature Filtering Methods And Diffusion Maps, Rui Xu, Steven Damelin, Boaz Nadler, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The importance of gene expression data in cancer diagnosis and treatment by now has been widely recognized by cancer researchers in recent years. However, one of the major challenges in the computational analysis of such data is the curse of dimensionality, due to the overwhelming number of measures of gene expression levels versus the small number of samples. Here, we use a two-step method to reduce the dimension of gene expression data. At first, we extract a subset of genes based on the statistical characteristics of their corresponding gene expression measurements. For further dimensionality reduction, we then apply diffusion maps, …

Multimodal Solution For A Rectangular Waveguide Radiating Into A Multilayered Dielectric Structure And Its Application For Dielectric Property And Thickness Evaluation, Mohammad Tayeb Ahmad Ghasr, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Open-ended rectangular waveguides are widely used for microwave and millimeter wave nondestructive testing applications. Applications have included detecting disbonds and delaminations in multilayered composite structures, thickness evaluation of dielectric sheets and coatings on metal substrates, etc. When inspecting a complex multilayered composite structure, made of generally lossy dielectric layers with arbitrary thicknesses and backing, the dielectric properties of a particular layer within the structure is of particular interest, such being health monitoring of structures such as radomes. The same is also true where one may be interested in the thickness or more importantly thickness variation of a particular layer within …

Knowledge-Based System To Support Site Investigation For Safety Improvement, Andrew P. Tarko, Andrew Kwasniak, Jorge Ramos

JTRP Technical Reports

Specialists in transportation and other areas of engineering are trying to improve road safety. The most difficult part is determining the road features, driver behaviors, and vehicular failures that unduly increase the risk of crash. To help INDOT safety investigation teams, a previous research project developed a prototype Road Safety Investigation Tool (RSIT) for two-way stop-controlled intersections. The research summarized here has evaluated the prototype RSIT and has developed a new version RSIT2 that has incorporated the findings of the evaluation.

The evaluation of the RSIT prototype confirmed usefulness of the proposed methodology. The tool has been applied to two …

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 …

Sources Of End Zone Cracking Of Pretensioned Concrete Girders, Christie J. Hasenkamp, Sameh S. Badie, Christopher Y. Tuan, Maher K. Tadros

Civil Engineering Faculty Proceedings & Presentations

Recent developments of high performance concrete, increasing amounts of prestressing, and increasing use of deep girders have resulted in increasing popularity of precast pretensioned concrete girders in bridge construction. These developments have increasingly contributed to end zone cracking. This paper summarizes the interim results of an ongoing research sponsored by the National Cooperative Highway Research Program (NCHRP) Project 18-14. The objectives of the research are: (1) to establish procedures for the acceptance, repair, or rejection of precast/prestressed concrete girders with longitudinal web cracking, and (2) to prepare a user's manual for the application of these procedures. The results from a …

Bioengineering Cartilage Growth, Maturation, And Form, Gregory M. Williams, Stephen M. Klisch, Robert L. Sah

Mechanical Engineering

Cartilage of articular joints grows and matures to achieve characteristic sizes, forms, and functional properties. Through these processes, the tissue not only serves as a template for bone growth but also yields mature articular cartilage providing joints with a low-friction, wear-resistant bearing material. The study of cartilage growth and maturation is a focus of both cartilage biologists and bioengineers with one goal of trying to create biologic tissue substitutes for the repair of damaged joints. Experimental approaches both in vivo and in vitro are being used to better understand the mechanisms and regulation of growth and maturation processes. This knowledge …

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 …

Methodology For Reverse Supply Chain Design In Consumer Electronics Industry, Santhanam Rajagopalan

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Reverse Logistics (RL), the art and science of moving goods typically from the end consumer towards the upstream end of supply chains, has been the subject of many strategic meetings in organizations today. This is attributed mainly due to the tighter federal environmental legislations on product returns and a hugely untapped potential that has been often overlooked by the managers. Traditionally, enterprises spend most of the improvement initiatives in optimizing its forward supply chain (FSC) performance that aims to delight the end consumer. However, it is not a panacea by itself in the process of continuously satisfying the end customer. …

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.

Proctor Compaction Testing, Joshua Connelly, Wayne Jensen, Paul Harmon

Nebraska Department of Transportation: Research Reports

No abstract provided.

Protocols For Dynamic Spectrum Access, Thomas Royster

All Dissertations

Protocols for modulation selection, initial transmitter power adjustment, modulation and coding adaptation, and transmitter power adaptation are presented. Most adaptive protocols in the literature are for full-duplex communication and they require channel estimation (e.g., using training symbols); however, our protocols are for half-duplex packet radios and they do not require estimation of the channel for adaptation. Instead, our protocols are driven by statistics that can be derived from the receiver's demodulator or decoder. We present the protocols in the context of their application to dynamic spectrum access networks. Our protocols are designed for adaptive radios, of which software-defined radios and …

Anaerobic Biodegradation Of Ethylene Dibromide And 1,2-Dichloroethane In The Presence Of Fuel Hydrocarbons, James Henderson

All Dissertations

Field evidence from underground storage tank (UST) sites where leaded gasoline leaked indicates the lead scavengers 1,2-dibromoethane (ethylene dibromide, or EDB) and 1,2-dichloroethane (1,2-DCA) may be present in groundwater at levels that pose unacceptable risk. These compounds are seldom tested for at UST sites. Although dehalogenation of EDB and 1,2-DCA is known to occur, the effect of fuel hydrocarbons on their biodegradability under anaerobic conditions is poorly understood. Microcosms (2 L glass bottles) were prepared with soil and groundwater from a UST site in Clemson, South Carolina, using samples collected from the source (containing residual fuel) and less contaminated downgradient …

Transitional Flow Between Orifice And Non-Orifice Regimes At A Rectangular Canal Gate, Omar Alminagorta Cabezas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The main objective of this research was to analyze the hydraulic transition between non-orifice and orifice flow regimes at a rectangular sluice gate through the calibration of various discharge equations, and determining the value of a coefficient, which defines the transition between orifice and non-orifice flow conditions. The second objective was to determine whether a single equation could be used to represent the stage-discharge relationship for both free and submerged non-orifice flow through a rectangular sluice gate.

Several hundred data sets were collected in a hydraulic laboratory, each including the measurement of water upstream depth and downstream for five different …

Determining The Flow Characteristics Of A Perfusion Device For Donor Heart Transport, Michael Louis Cobert

Bioengineering Theses - Archive

Current technology has limits organ transport for transplantation to static storage, thereby reducing the reasonable distance of travel. Continuous machine perfusion has been proposed as a viable alternative to improving function and outcome. A series of studies with such a device have been developed to elucidate the method by which optimal results can be achieved. Adult mongrel dog hearts were established in a device that provided continuous perfusion of oxygenated fluid and enabled precise control of flow rate, oxygenation, and fluid temperature. The first series of experiments sought to determine an optimal flow rate for tissue perfusion at one of …

Real-Time Raman Spectroscopy And Wide-Angle X-Ray Diffraction During Single-Layer And Multi-Layer Blown Film Extrusion, Giriprasath Gururajan

All Dissertations

Properties exhibited by blown films are controlled by the microstructure developed during their processing. Therefore, real-time measurement of microstructure during the blown film extrusion can help in better control and optimization of the process needed to obtain desired properties. The objectives of this research were (i) to conduct real-time microstructural measurements during single-layer and multi-layer blown film extrusion of polypropylene (PP) and low-density polyethylene (LDPE) using real-time Raman spectroscopy; (ii) to conduct real-time wide-angle X-ray diffraction (WAXD) during single-layer blown film extrusion of LDPE to obtain crystallinity and orientation values during the process; and (iii) to investigate the effect of …

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 …

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 …

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 …

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) …

Numerical Thermal-Fluid Analysis Of A Liquid Cooled Novel 3-D Electronic Package, Aron Meyer

Mechanical Engineering Undergraduate Honors Theses

The need for smaller and more powerful processors has become more and more important in recent times. This need is nowhere more evident than in the military where the ability to process large amounts of data quickly and accurately can save lives. So the University of Arkansas has been researching a new chip design, the 3-D stack-up thru-silicon via chip. This has several benefits over the traditional chip designs, but comes at the price of having more heat to be dissipated. Due to the need to dissipate up to 20 watts per wafer a liquid cooling system was used with …

Improved Frequency-Domain Channel Estimation For Fast Time-Varying Mimo-Scfde Channels, Y. Rosa Zheng, Jian Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

A frequency-domain channel estimation method is proposed for time-varying multiple-input multiple output (MIMO) single-carrier frequency-domain equalization (SC-FDE). The proposed method uses frequency-domain interpolation to obtain channel frequency responses of data blocks from estimated responses of two adjacent pilot blocks. It takes the channel temporal-spatial correlation into account to achieve minimum mean squared error (MMSE) estimation, thus improving the accuracy and effectiveness in high Doppler scenarios. The simulation results of the bit error rate (BER) performances show that the proposed method works well for fast time-varying channels with Doppler spread as high as 300 Hz while maintaining over 70% data efficiency.

Potential Application Of The Modulated Scatterer Technique To Multilayered Material Evaluation And Health Monitoring, Kristen M. Munoz, Amy K. Perrey, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Modulated scatterer technique (MST) is based on illuminating a small antenna, usually a dipole, loaded with a PIN diode, with an electromagnetic wave. The scattered (or reflected) wave from the probe may then be used to determine dielectric properties of the material in which the probe is located or embedded. The PIN diode is turned "on" and "off" which not only changes the impedance of the probe, but also modulates (with the same rate) the reflection from the probe. A major challenge associated with MST is detecting and distinguishing the desired probe response in the ever-present reflections from surrounding structures …

Using Tem Cell Measurements To Estimate The Maximum Radiation From Pcbs With Cables Due To Magnetic Field Coupling, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

Common-mode currents can be induced on cables attached to printed circuit boards (PCBs) due to electric and magnetic field coupling. This paper describes a technique for using transverse electromagnetic (TEM) cell measurements to obtain an effective common-mode voltage (or magnetic moment) that quantifies the ability of traces and integrated circuits on PCBs to drive common-mode currents onto cables due to magnetic field coupling. This equivalent common-mode voltage can be used to reduce the complexity of full-wave models that calculate the radiated emissions from a system containing the board. It can also be used without full-wave modeling to provide a …

A Variable Partitioning Strategy For The Multirate Method In Power Systems, Jingjia Chen, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

An application of the multirate method to differential and algebraic equations (DAEs) is discussed in this paper. Based on the specific formulation of the power systems algebraic equations, an effective algebraic variable partitioning strategy is developed and implemented. The application of the partitioning strategy to an example power system provides validation of the proposed partitioning strategy in terms of speed-up and accuracy.

Effects Of Natural And Accelerated Weathering On The Performance Of Locally Manufactured Polymer-Modified Bituminous Waterproofing Membranes, Rauda Ali Saeed Al Saadi

Theses

As in most industrial sectors, today there is a growing preoccupation about product quality. Since waterproofing systems are intended to have the longest possible service life, one of the most critical quality features is their aging performance. As a result, the importance of aging tests is steadily growing, especially in the hot-dry climate zones.

Polymer-modified bituminous waterproofing membranes are normally exposed to solar radiation and various weathering conditions when used in residential and commercial buildings. They are attacked and deteriorated to some degree by environmental factors such as heat, radiation, especially ultraviolet, moisture and gases. The weathering (aging) consequences commonly …

Contributions Of Online Visual Feedback To The Learning And Generalization Of Novel Finger Coordination Patterns, Xiaolin Liu, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We explored how people learn new ways to move objects through space using neuromuscular control signals having more degrees of freedom than needed to unambiguously specify object location. Subjects wore an instrumented glove that recorded finger motions. A linear transformation matrix projected joint angle signals (a high-dimensional control vector) onto a two-dimensional cursor position on a video monitor. We assessed how visual information influences learning and generalization of novel finger coordination patterns as subjects practiced using hand gestures to manipulate cursor location. Three groups of test subjects practiced moving a visible cursor between different sets of screen targets. The hand-to-screen …

Electron And Spin Transport In The Presence Of A Complex Absorbing Potential, Fatih Dogan, Wonkee Kim, C. Blois, Frank Marsiglio

Materials Science and Engineering Faculty Research & Creative Works

We examine the impact of a complex absorbing potential on electron transport both in the continuum and on a lattice. This requires the use of non-Hermitian Hamiltonians; the required formalism is briefly outlined. The lattice formulation allows us to study the interesting problem of an electron interacting with a stationary spin and the subsequent time evolution of the electron and spin properties as the electron is absorbed after the initial interaction. Remarkably, the properties of the localized spin are affected “at a distance” by the interaction of the (now entangled) electron with a complex potential.

Estimating Highway Maintenance Work 2008, Ohio Department Of Transportation, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This manual is founded upon a problem index that walks through a number of equations that will estimate the maintenance work required in areas such as bridge deck repair, chip and seal, crack sealing, mowing, road salt application, salt spreader calibration, and many more everyday road maintenance operations. The manual also includes an appendix to help with lengths, areas, volumes, rates, equivalents, and rules.

Optimizing Performance Of Conductive Nanoparticle-Filled Membranes, Alison Chen

Honors Scholar Theses

Conductive membranes were prepared by magnetic alignment of graphite-coated iron nanoparticles (GCINs) in a polyisobutylene (PIB) matrix, which was cast onto an interdigitated surface electrode. Toluene and tetrahydrofuran (THF) were used as solvents for the casting solution. Different molecular weights of PIB and solutions with concentrations ranging from 0.05- to 50-wt% were explored to optimize the mechanical and physical properties of the membrane. The amount of GCINs used in the membranes ranged from 0.1- to 2.5-wt%, and a sonicator was used to disperse the particles in the membrane. Sedimentation and surfactant studies were conducted to investigate the dispersion of GCINs …