Engineering Commons^™

Effects Of Polishing Shot-Peened Surfaces On Fretting Fatigue Behavior Of Ti-6al-4v, Kasey S. Scheel

Theses and Dissertations

The research of this thesis was done to investigate the effects of polishing a shot-peened specimen of Ti-6Al-4V on the fretting fatigue life of that specimen. The shot-peening process, though one of the most beneficial techniques in prolonging fretting fatigue life, creates a textured surface that may lead to problems on the micro level. This research was done in an attempt to further improve the peening process by examining the effects of another surface treatment to be used in conjunction, surface polishing. The rough peened surface may contain abrupt changes in surface geometry that act as stress risers, which are …

An Investigation Of The Effects Of Boundary Avoidance On Pilot Tracking, Randy D. Warren

Theses and Dissertations

Pilot-Involved Oscillations (PIOs) remain a significant issue in the design, testing and operations of aerospace vehicles. Traditional methods for predicting, describing, and analyzing these events have provided the community with improved methods for minimizing the occurrences of PIOs. However, these events continue to occur over a wide range of aerospace vehicle types and over a wide range of pilot acumen. The introduction of boundary avoidance tracking (BAT) by Mr. William Gray in 2004 added a missing piece to the PIO puzzle. This theory presented that PIOs may result from increasing pilot gain resulting not from maintaining a specified condition, but …

Site Investigation Of Bridges Along I-24 In Western Kentucky, Wael Zatar, Issam E. Harik, Peng Yuan

Kentucky Transportation Center Research Report

Determination of the seismic risk of the I-24 bridges requires evaluating the current condition of all individual elements of the bridges. All bridges along the I-24 were visually inspected, pictured, and the records were stored in a database. Data of the visual inspection and the pictures were combined to form the completed site inspection forms of the I-24 bridges. Main visually observed deficiencies of the bridge elements were pointed out. The site inspection forms of all bridges on/over the I-24 in western Kentucky are used together with the bridge inventory to obtain different statistical figures regarding the characteristics of the …

Detailed Seismic Evaluation Of Bridges Along I-24 In Western Kentucky, Ching Chiaw Choo, Issam E. Harik, Peng Yuan

Kentucky Transportation Center Research Report

This report presents a seismic rating system and a detailed evaluation procedure for selected highway bridges on/over I-24 in Western Kentucky near the New Madrid Seismic Zone (NMSZ). The rating system, based upon structural vulnerability, seismic and geotechnical hazards, and socioeconomic factors, was used to rank 127 (82 on and 45 over I-24) bridges on/over I-24. A total of 14 bridges were selected and subsequently evaluated using a capacity/demand ratio method outlined in the Seismic Retrofitting Manual for Highway Bridges by the Federal Highway Administration. The focus was on four bridge components; namely the expansion joints, bearings, columns, and footings. …

Outsourcing In Ireland: A Literature Review And Survey Perspective To Construct An Outsourcing Roadmap, Aoife O'Riordan, Edward Sweeney

Conference papers

This paper investigates what is happening in Ireland at the moment regards outsourcing. It looks into the literature review and the survey conducted. The research took place over a period of two years, initially as a literature review, and then the survey was conducted through the mediums of e-mail and the postal service. The survey analysis found that Ireland was the most likely place for Irish companies to outsource to, and that nearly 40 percent of the companies that have been surveyed have started on their latest outsourcing initiative since 2004. This indicates that outsourcing is still important on the …

Seismic Evaluation Of The Cumberland River Bridges On I-24 In Western Kentucky, Wael A. Zatar, Wei-Xin Ren, Issam E. Harik

Kentucky Transportation Center Research Report

The main objective of this study is to assess the structural integrity of the I-24 parallel bridges at the Cumberland River crossing in western Kentucky. Due to its importance, the bridge is evaluated for the 250-year event and the maximum credible 500-year event. The scope of the work included: 1) Field testing of the main bridge; 2) Finite element modeling and calibration; 3) Time-history seismic response analysis for the main spans; and 4) Seismic evaluation for both the main and the approach spans. The seismic analysis for the 250-year event indicates that the main spans of the bridge can resist …

Seismic Evaluation Of The Tennessee River Bridges On I-24 In Western Kentucky, Tong Zhao, Wei-Xin Ren, Issam E. Harik, Jin-Dong Hu

Kentucky Transportation Center Research Report

This report presents the seismic evaluation of the approaches and parallel bridges on I-24 crossing the Tennessee River between Marshall and Livingston counties in Western Kentucky. The main bridges are steel tied-arch bridges. The bridges are situated within the influence of the New Madrid Seismic Zone. The seismic evaluation program consisted of field testing, 3-dimensional finite element modeling and seismic response analysis. The dynamic properties of the main bridges are determined through field testing, and are used to calibrate the finite element models. The finite element model is then subjected to time histories of the 250-year and 500-year earthquake events. …

Preliminary Seismic Evaluation And Ranking Of Bridges Along I-24 In Western Kentucky, Wael Zatar, Issam E. Harik, Peng Yuan, Ching Chiaw Choo

Kentucky Transportation Center Research Report

This study represents one of the Seismic Evaluation of I-24 Bridges investigative series. The focus is on preliminary seismic evaluation and ranking of bridges according to their seismic vulnerability. Bridges along I-24 are considered in this investigation. The ranking will assist in identifying and prioritizing bridges for secondary evaluation, retrofit measure, or other course of action. The rating system described herein is based on a methodology provided by the FHWA Retrofitting Manual for highway bridges. One hundred and twenty seven (127) highway bridges were evaluated and rated in this process for projected 50-year and 250-year seismic events. The Tennessee River …

Post Earthquake Investigation Field Manual For The State Of Kentucky, Ann G. Sardo, Thomas E. Sardo, Issam E. Harik

Kentucky Transportation Center Research Report

The rapid assessment of a bridge structure’s safety and functionality is an essential component to restoring vital lifeline routes after a major earthquake. Appropriate posting categories are used to assure the safety of the traveling public. The objective of this manual is to provide a rapid and efficient method of inspecting bridge structures after an earthquake. The primary users of this manual are intended to be the initial Kentucky Transportation Cabinet personnel who will initially reach the bridge sites. It is recognized that such first-line personnel will possess a variety of backgrounds and, therefore, a systematic method of evaluating the …

Seismic Evaluation Of I-24 Bridges And Embankments In Western Kentucky–Summary Report, Wael A. Zatar, Issam E. Harik, Ching Chiaw Choo

Kentucky Transportation Center Research Report

I-24 is considered as one of the high priority and emergency routes in the region. Hence, it is essential that I-24 remains functional and operational after an earthquake event. The objective of this study is to perform seismic evaluation and risk assessment of bridges and embankments along I-24 in western Kentucky. The assessment assists identifying and prioritizing bridges that are susceptible to failure.

The study aims at evaluating the seismic risk for 127 bridges, of which 82 bridges lies on I-24 and 45 bridges cross over I-24. This report is the first (1st) in a series of seven reports for …

Jecp—A Java Electron Crystallography Project, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

JECP stands for a java electron crystallography project that includes a series of practical java stand-alone programs for electron diffraction/microscopy and crystallography applications. The aim of the JECP project is twofold, i) as teaching tools to show students the principles of electron diffraction/microscopy and crystallography, ii) as research tools to analyze experimental results. Although there are commercial and public domain computer programs available that allow a user to simulate electron diffraction patterns or processing HREM images, there are always situations when we need to perform operations that are not a feature of any of the existing programs. The programs in …

The Doe Consortium For Research On Enhancing Carbon Sequestration In Terrestial Ecosystems: Fy 2007-2011 Five Year Science Plan, U.S. Department Of Energy

United States Department of Energy: Publications

The DOE Consortium for Research on Enhancing Carbon Sequestration in Terrestrial Ecosystems (CSiTE) conducts multi-scale research to acquire basic knowledge for underpinning the implementation of soil carbon (C) sequestration in an environmentally acceptable and economically feasible manner. Research is based on the premise that identifying and understanding the basic mechanisms controlling sequestration across managed and unmanaged ecosystems are fundamental to developing approaches for enhancing C capture and long-term storage. The goal is to discover and characterize links among physical, chemical, and biological processes controlling soil C dynamics and storage at a mechanistic level to facilitate the enhancement of C storage …

The Effect Of Plate Rotation On The Stiffness Of Femoral Liss: A Mechanical Study, Afshin Khalafi, Shane Curtiss, Scott Hazelwood, Philip Wolinsky

Biomedical Engineering

Objective: Malposition of the femoral Less Invasive Stabilization System (LISS) plate may alter its biomechanical behavior. This study compares the mechanical stability of ‘‘correctly’’ affixed LISS plates matching the slope of the lateral femoral condyle to ‘‘incorrectly’’ placed LISS plates fixed in external rotation relative to the distal femur.

Methods: A fracture gap model was created to simulate a comminuted supracondylar femur fracture (AO/OTA33-A3). Fixation was achieved using two different plate positions: the LISS plate was either placed ‘‘correctly’’ by internally rotating the plate to match the slope of the lateral femoral condyle, or ‘‘incorrectly’’ by externally rotating the plate …

Analysis Of The Double-Tiered Three-Battery Switched Capacitor Battery Balancing System, Andrew Baughman, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

The auto industry is progressing towards hybrid and fully electric vehicles in their future car models. These vehicles need a power plant that is reliable during the lifetime of the car. Battery and ultra-capacitor capacity imbalances stemming from manufacturing and ensuing driving environment and operational usage affect voltage levels, which must adhere to strict limits to ensure the safety of the driver. A double-tiered capacitive shuttling technique is applied to an idealized three-battery system simulation in order to balance the voltages. Parameters in the system are varied and their effects on the system determined. Results are compared to a single-tiered …

A General Purpose Framework For Wireless Sensor Network Applications, Ayman Z. Faza, Sahra Sedigh

Electrical and Computer Engineering Faculty Research & Creative Works

Wireless sensor networks are becoming a basis for a rapidly increasing range of applications. Habitat, flood, and wildfire monitoring are interesting examples of such applications. Each application has different requirements in terms of node functionalities, network size, complexity and cost; therefore, it is worthwhile time investment to design and implement a general purpose framework for wireless sensor networks that would be adaptable to any monitoring application of interest with a minimum amount of effort. In this manuscript, we propose a basic structure for such a framework and highlight a number of challenges anticipated during the course of this doctoral research.

An Autonomous And Adaptable Wireless Device For Flood Monitoring, Valerio Plessi, Filippo Bastianini, Sahra Sedigh

Electrical and Computer Engineering Faculty Research & Creative Works

Wireless devices can be used to monitor and record a broad range of phenomena. Their advantages include ease of installation and maintenance and considerable reduction in wiring costs. The addition of battery power and radio communication to such wireless devices can result in a completely The operating environment of monitoring systems is often hostile, due to temperature fluctuations, humidity, electromagnetic noise, and other interfering phenomena. The system should be able to adapt to changing conditions to maintain dependability in its operations This paper presents the case study of adapting a flood detection device to the environmental threat of submersion.

Trustworthy Computing Needs, Ann K. Miller

Electrical and Computer Engineering Faculty Research & Creative Works

The very label "critical infrastructure" implies that such systems are important. They are. Within the US alone, there are approximately 28,600 networked Federal Deposit Insurance Corporation (FDIC) institutions, 2 million miles of oil/gas pipelines, 2,800 power plants with 300,000 production sites, 104 nuclear power plants, 80,000 dams, 60,000 chemical plants, 87,000 food processing plants, and 1,600 water treatment plants. And, this is just part of our national infrastructure. Add to this telecommunications and other "everyday" utilities and the scope is enormous. Most of these systems, alone, would qualify as a network-centric system; that is, a system of systems (SoS) whose …

Obtaining Mode Mixity For A Bimaterial Interface Crack Using The Virtual Crack Closure Technique, A. Agrawal, Anette M. Karlsson

Mechanical Engineering Faculty Publications

We review, unify and extend work pertaining to evaluating mode mixity of interfacial fracture utilizing the virtual crack closure technique (VCCT). From the VCCT, components of the strain energy release rate (SERR) are obtained using the forces and displacements near the crack tip corresponding to the opening and sliding contributions. Unfortunately, these components depend on the crack extension size, Δ, used in the VCCT. It follows that a mode mixity based upon these components also will depend on the crack extension size. However, the components of the strain energy release rate can be used for determining the complex stress intensity …

Using System-On-A-Programmable-Chip Technology To Design Embedded Systems, Tyson S. Hall, James O. Hamblen

Faculty Works

This paper describes the tools, techniques, and devices used to design embedded products with system–on-a-chip (SoC) type solutions using a large Field Programmable Gate Array (FPGA) with an internal processor core. This new FPGA-based approach is called system-on-a-programmable-chip (SoPC ). The performance tradeoffs present in SoPC systems is compared to more traditional design approaches. Commercial devices, processor cores, and CAD tool flows are described.

The issues in SoPC hardware/software design tradeoffs are examined and three example SoPC designs are presented as case studies.

Design Of Piezoresistive Mems Force And Displacement Sensors, Tyler Lane Waterfall

Theses and Dissertations

MEMS (MicroElectroMechanical Systems) sensors are used in acceleration, flow, pressure and force sensing applications on the micro and macro levels. Much research has focused on improving sensor precision, range, reliability, and ease of manufacture and operation. One exciting possibility for improving the capability of micro sensors lies in exploiting the piezoresistive properties of silicon, the material of choice in many MEMS fabrication processes. Piezoresistivity—the change of electrical resistance due to an applied strain—is a valuable material property of silicon due to its potential for high signal output and on-chip and feedback-control possibilities. However, successful design of piezoresistive micro sensors requires …

Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Some Of Its Properties: The Case Of Surgical Simplex® P, S. Madigan, Mark R. Towler, G. Lewis

Chemical and Biochemical Engineering Faculty Research & Creative Works

Influence of two changes in the composition of a self-curing acrylic bone cement on some of its properties are discussed. Acrylic bone cements are widely used in orthopedic surgery for the fixation of joint prosthesis and in vertebroplasty and kyphoplasty for the stabilization and augmentation of fractured vertebrae. The cement's curing process is the result of a free-radical polymerization of a mixture of poly (methyl 1 methacrylate) [PMMA] containing powder and a liquid monomer that has methyl methacrylate (MMA) in it. It is initiated by the decomposition of benzoyl peroxide (BPO) in the powder, activated by a tertiary amine in …

The Influence Of Ultrasonic Setting On Fluoride Release From Glass Polyalkenoate Cements, N. Rushe, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The effects of ultrasonic setting on fluoride release from glass polyalkenoate cements (GPC) were investigated. Cements based on two different aluminosilicate glasses that contained silica, alumina, phosphate, and strontia were used for the experiment. A series of GPCs were examined to show that increased release F^- ion occurs, regardless of GPC composition. The results show that there is a greater release of fluoride from the ultrasonically set samples than those set chemically, regardless of the chemical composition. The snap set caused by the ultrasound is likely to be due to a combination of cavitation, improved mixing of the constituents, …

Calcium And Zinc Ion Release From Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Mark R. Towler, S. Kenny, D. Boyd, T. Pembroke, M. Buggy, A. Guida, R. G. Hill

Chemical and Biochemical Engineering Faculty Research & Creative Works

Calcium and zinc ion release from hydroxyapatite-zinc oxide-poly (acrylic acid) (HAZnO-PAA) composite cements into deionised water was investigated as a function of HA content, PAA concentration, PAA molecular weight and maturation time. At any given maturation time, zinc ion release was constant until the HA content was at the maximum loading (60 wt%) resulting in the cement matrix breaking up, allowing exacerbated ion release. The calcium ion release increased with increased HA content in the composite until the maximum loading where the release drops off. Up to this point, the release of both ionic species was proportional to square root …

Flow Regime Identification In A Bubble Column Based On Both Statistical And Chaotic Parameters Applied To Computed Tomography Data, Stoyan Nedeltchev, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Kolmogorov Entropy (KE) Algorithm Was Applied Successfully to Single Source Γ-Ray Computed Tomography (CT) Data Measured in a 0.162 M ID Bubble Column Equipped with a Perforated Plate Distributor (163 Holes · Ø 1.32 Mm). Dried Air Was Used as the Gas Phase and Therminol LT (ΡL = 886 Kg M-3, ΜL = 0.88 · 10-3 Pa S, Σ = 17 · 10-3 N M-1) Was Used as a Liquid Phase. Three Different Pressures, P, of 0.1, 0.4, and 1.0 MPa Were Examined. at Each Pressure the Superficial Gas Velocity, UG, Was Increased Stepwise by Steps of 0.01 Ms-1 …

Electrowetting Droplet Microfluidics On A Single Planar Surface, Christopher G. Cooney, Chao Yi Chen, Michael R. Emerling, Ali Nadim, James D. Sterling

Business and Information Technology Faculty Research & Creative Works

Electrowetting refers to an electrostatically induced reduction in the contact angle of an electrically conductive liquid droplet on a surface. Most designs ground the droplet by either sandwiching the droplet with a grounding plate on top or by inserting a wire into the droplet. Washizu and others have developed systems capable of generating droplet motion without a top plate while allowing the droplet potential to float. In contrast to these designs, we demonstrate an electrowetting system in which the droplet can be electrically grounded from below using thin conductive lines on top of the dielectric layer. This alternative method of …

Dynamic Maximum Power Point Tracking Of Photovoltaic Arrays Using Ripple Correlation Control, Trishan Esram, Jonathan W. Kimball, Philip T. Krein, Patrick L. Chapman, Pallab Midya

Electrical and Computer Engineering Faculty Research & Creative Works

A dynamically rapid method used for tracking the maximum power point of photovoltaic arrays, known as ripple correlation control, is presented and verified against experiment. The technique takes advantage of the signal ripple, which is automatically present in power converters. The ripple is interpreted as a perturbation from which a gradient ascent optimization can be realized. The technique converges asymptotically at maximum speed to the maximum power point without the benefit of any array parameters or measurements. The technique has simple circuit implementations.

New Double Input Dc-Dc Converters For Automotive Applications, Krishna P. Yalamanchili, Mehdi Ferdowsi, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

The energy storage unit is one of the most important subsystems in the structure of hybrid electric vehicles since it directly impacts the performance, fuel economy, cost, and weight of the vehicle. New structures for the energy storage unit, which utilize both batteries and ultracapacitors, are widely under investigation. In order to fully utilize the advantages of each energy storage device, employment of multi-input power converters is inevitable. In this paper, two new double input converters are introduced. Their different operating modes are analyzed and their voltage transfer ratios are derived. Simulation results are used to verify the expected operational …

2006 Model Highway County Ordinances, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This report is intended to provide model ordinances for common situations for county highway departments and local street departments in Indiana where no current sample or model ordinance is readily available. Information to prepare model ordinances was collected from other Indiana counties and municipalities. Some of the model ordinances were created at the request of local highway and street departments.

The purpose of this report was not to duplicate regulations already in place such as where state governments cover issues such road signage, or traffic control, but to provide references for situations that have no other regulation or where specific …

A New Class Of Miniature Embedded Inverted-F Antennas (Ifas) For 2.4 Ghz Wlan Application, Mohammed Z. Azad, Mohammod Ali

Faculty Publications

A new class of miniature printed embedded inverted-F antennas are proposed for operation in the 2.4-2.485 GHz wireless local-area network band. One of the proposed antennas on FR4 substrate (dielectric constant = 4.4) measures 9.2 mm by 4.1 mm and has a bandwidth of 3.5%. The peak gain of this antenna is 1.4 dBi. An overall size reduction of 70% is achieved compared to a conventional inverted-F antenna. Effects of dielectric loss tangent and material conductivity on the bandwidth and efficiency of these antennas are also investigated. Finally, two embedded antenna elements are analyzed to demonstrate the feasibility for a …

The 1.6-Kv Algan/Gan Hfets, N. Tipirneni, Alexei Koudymov, V. Adivarahan, Jinwei Yang, Grigory Simin, Asif Khan

Faculty Publications

The breakdown voltages in unpassivated nonfield-plated AlGan/GaN HFETs on sapphire substrates were studied. These studies reveal that the breakdown is limited by the surface flashover rather than by the AlGan/GaN channel. after elimination of the surface flashover in air, the breakdown voltage scaled linearly with the gate-drain spacing reaching 1.6 kV at 20 mu m. The corresponding static ON-resistance was as low as 3.4 m Omega(.)cm(2). This translates to a power device figure-of-merit V-BR(2)/R-ON = 7.5 x 10(8) V-2 . n(-1) cm(-2), which, to date, is among the best reported values for an AlGan/GaN HFET.