Engineering Commons^™

How Can We Best Manage Freeway Congestion?, Robert Bertini, Christopher Monsere

TREC Project Briefs

Researchers from Portland State University evaluate Oregon’s Implementation of System-Wide Adaptive Ramp Metering (SWARM).

An Object-Oriented Approach For Modeling And Simulation Of Crack Growth In Cyclically Loaded Structures, D. Cojocaru, Anette M. Karlsson

Mechanical Engineering Faculty Publications

We present an object-oriented modeling frame for simulating crack propagation due to cyclic loadings. Central to the approach is that the crack propagates when a user-defined propagation criterion is fulfilled, i.e., the crack propagation rate is not prescribed but predicted. The approach utilizes the commercial finite element software package ABAQUS and its associated Python based scripting interface. The crack propagation is simulated by a generalized node release technique. If the propagation criteria are satisfied in the end of a cycle, the crack is allowed to propagate. The incremental crack growth is inferred from an iterative investigation of the propagation criteria. …

Hydrodynamic Loading Of Microcantilevers Oscillating Near Rigid Walls, Ryan C. Tung, Jana Anirban, Arvind Raman

Birck and NCN Publications

The vibrations of microcantilevers in atomic force microscopes (AFMs) or radio frequency (RF) switches are strongly influenced by the viscous hydrodynamics of the surrounding fluid in the vicinity of a rigid wall. While prior efforts to model this hydrodynamic loading have focused on squeeze film damping effects at high Knudsen and squeeze numbers, the regimes of low Knudsen and squeeze numbers are also very important for which squeeze film models need to be discarded in favor of unsteady Stokes hydrodynamics. We extend the work of Green and Sader [Phys Fluids 17, 073102 (2005); J. Appl. Phys. 98, 114913 (2005)] and …

Theoretical Determination Of Subcritical Sequent Depths For Complete And Incomplete Hydraulic Jumps In Closed Conduits Of Any Shape, Nathan John Lowe

Theses and Dissertations

In order to predict hydraulic jump characteristics for channel design, the jump height may be determined by calculating the subcritical sequent depth from momentum theory. In closed conduits, however, outlet submergence may fill the conduit entirely before the expected sequent depth is reached. This is called an incomplete or pressure jump (as opposed to a complete or free-surface jump), because pressure flow conditions prevail downstream. Since the momentum equation involves terms for the top width, area, and centroid of flow, the subcritical sequent depth is a function of the conduit shape in addition to the upstream depth and Froude number. …

Operations-Oriented Performance Measures For Freeway Management Systems: Final Report, Robert E. Brydia, Stephen P. Mattingly, Melanie L. Sattler, Auttawit Upayokin

Civil Engineering Faculty Publications - Archive

This report describes the second and final year activities of the project titled “Using Operations-Oriented Performance Measures to Support Freeway Management Systems.” Work activities included developing a prototype system architecture for testing the use of performance measures in real-time. Outputs from this effort included operator’s screens, a prototype database, and a concept of operations for using the real-time measures. Additional work showcased the application of a multi-criterion screening approach to the selection of competing performance measures.

Modeling, Analysis And Control Of Flexible Solid-State Hysteretic Actuators, Kushan Vora

All Theses

A distributed parameters modeling and control framework for flexible solid-state hysteretic actuator is presented in this work. For the simplicity of analysis, the actuator dynamic behavior is decoupled and treated separately from the hysteresis nonlinearity. To include the effects of widely-used flexural mechanisms, a mass-spring-damper boundary condition is considered for system. Moreover, the effect of electromechanical actuation is included as a concentrate force at the boundary. The problem is then divided into two parts: first part deals with free motion analysis of system in order to obtain eigenvalues and eigenfunctions using the expansion theorem and a standard eigenvalue problem procedure. …

Investigation Of The Merging Of Two Axisymmetric Turbulent Jets, Jeffrey Smith

All Theses

A study was done to determine the converging distance of two axisymmetric turbulent jets and to compare the experimental results with the Reichardt hypothesis. This experiment consisted of measuring the velocity profiles of the two jets and manipulating the momentum ratio between the jets. Through testing, it was determined that the Reichardt hypothesis while efficient, over predicts the converging distance of the jets by up to 25% in some cases.
An Acoustic Doppler Velocimeter (ADV) was used to take measurements across the path of the jets and monitored the velocity and the turbulent kinetic energy. After observing the velocity profiles, …

An Investigation On Spot-Weld Modeling Complexity For Crash Simulation, Srinivasan Vimalanathan

All Theses

In order to design car body structures which are safe during crash, modern automotive manufacturers perform both full-scale experimental crash tests and computer simulation of vehicle crash events using commercially available Finite Element Analysis (FEA) packages such as ABAQUS or LS-DYNA. Use of crash simulations significantly reduces the number of real time crash experiments needed and reduces the time required for design changes. However, in order to capture accurately crash behavior during high-speed impact, a large amount of detailed FEA modeling features such as number and types of elements, mesh element size, number of components, different types of connectors, material …

Synthesis And Characterization Of Macromolecular Layers Grafted To Polymer Surfaces, Oleksandr Burtovyy

All Dissertations

The composition and behavior of surfaces and interfaces play a pivotal role in dictating the overall efficiency of the majority of polymeric materials and devices. Surface properties of the materials can be altered using surface modification techniques. It is necessary to highlight that successful methods of surface modification should affect only the upper layer of the polymer material without changing bulk properties. The processes must introduce new functionalities to the surface, optimize surface roughness, lubrication, hydrophobicity, hydrophilicity, adhesion, conductivity, and/or biocompatibility.
Research presented in this dissertation is dedicated to the synthesis, characterization, and application of thin macromolecular layers anchored to …

Design For Manufacturing (Dfm) Methodology To Implement Friction Stir Welding (Fsw) For Automobile Chassis Fabrication, Harish Bagaitkar, Venkat Allada

Engineering Management and Systems Engineering Faculty Research & Creative Works

The manufacturing functional feasibility of implementing Friction Stir Welding (FSW) for automobile chassis fabrication is discussed using a case study. in the case study, the Design for Manufacturing (DFM) principles are applied to manufacture an aluminum automobile chassis. Various DFM issues are addressed while proposing the FSW technique as an alternative to laser welding and metal inert gas welding techniques. DFM guidelines involving joint design change, component geometries, and component elimination are discussed in this paper. by making appropriate changes in the component geometries and joint designs and eliminating some components, more than 50% of the joints in the example …

Comparing Component Functional Template Modeling Experimental Results In An Undergraduate Level Engineering Design Course, Daniel Abbott, Katie Grantham Lough

Engineering Management and Systems Engineering Faculty Research & Creative Works

Component functional templates are a foundational tool, for the functional modeling method, that novice users can implement to develop functional modeling skills and produce better results by not requiring the modeler to have extensive background knowledge in the method. the templates provide common function layouts of ordinary electromechanical components that are based on historic data collected from design information on a wide range of consumer products. a previous experiment has been performed on a sophomore level design class to assess the change in quality between functional modeling results with and without the use of component functional templates. to address further …

Xftsp: A Tool For Time Series Prediction By Means Of Fuzzy Inference Systems, Federico Montesino, Amaury Lendasse, Ángel Barriga

Engineering Management and Systems Engineering Faculty Research & Creative Works

A New Software Tool for Time Series Prediction by Means of Fuzzy Inference Systems is Reported. This Tool, Named XFTSP, implements a Novel Methodology for Time Series Prediction based on Methods for Automatic Fuzzy Systems Identification and Supervised Learning Combined with Statistical Methods for Nonparametric Residual Variance Estimation. XFTSP is Designed as a Tool Integrated in the Xfuzzy Development Environment for Fuzzy Systems. Experiments Carried Out on a Number of Time Series Benchmarks Show the Advantages of XFTSP in Terms of Both Accuracy and Computational Requirements as Compared Against Least-Squared Support Vector Machines, an Established Technique in the Field of …

Fully Evolvable Optimal Neurofuzzy Controller Using Adaptive Critic Designs, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

A near-optimal neurofuzzy external controller is designed in this paper for a static compensator (STATCOM) in a multimachine power system. The controller provides an auxiliary reference signal for the STATCOM in such a way that it improves the damping of the rotor speed deviations of its neighboring generators. A zero-order Takagi-Sugeno fuzzy rule base constitutes the core of the controller. A heuristic dynamic programming (HDP) based approach is used to further train the controller and enable it to provide nonlinear near-optimal control at different operating conditions of the power system. Based on the connectionist systems theory, the parameters of the …

Time-Domain Receiver Design For Mimo Underwater Acoustic Communications, Jun Tao, Yahong Rosa Zheng, Chengshan Xiao, T. C. Yang, Wen Bin Yang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we propose a time-domain receiver design scheme for high data rate single carrier multiple-input, multiple-output (MIMO) underwater acoustic communications. in this scheme, each received packet is artificially partitioned into blocks for processing. the MIMO channel is initially estimated using training blocks at the front of transmitted packets from all transducers. with the estimated MIMO channel, one data block following the training blocks is equalized. the phase rotation in the equalized data block is compensated by a group-wise phase correction operation, before symbol detection. the newly detected data block along with K - 1 previous data (or pilot) …

Distribution System Operation And Planning In The Presence Of Distributed Generation Technology, Gavin W. Jones, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Distributed generation (DG) is becoming an increasingly attractive multi-faceted paradigm in the field of power distribution as economic and environmental factors drive new technologies to be more efficient and less polluting than their earlier counterparts. an attempt is made to examine and compare three types of DG: diesel generators, microturbines, and small wind turbines within the structure of a distribution system. the DG types are compared in both steady-state and transient operation to determine which type is suitable for a particular application. Steady-state operation is examined under heavy loading conditions and each DG type is compared on the basis of …

Optimizing Micro-Grid Operations In The Presence Of Wind Generation, Nikhil K. Ardeshna, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Conceptually, a micro-grid can operate in parallel with the main grid system to support the grid voltage or as an isolated system to support customers isolated from the grid. in islanding operations, the micro-grid can continue to supply power to the customers thereby increasing the reliability of the power system. in a micro-grid with a significant percentage of wind power, a reactive power source would be needed to keep the wind power generating in islanded mode. the problem of load following is investigated in this situation. in addition, the use of Static Synchronous Compensator (STATCOM) and battery energy storage system …

Antibacterial Coatings For Medical Devices Based On Glass Polyalkenoate Cement Chemistry, A. Coughlan, D. Boyd, C. W.I. Douglas, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

A biofilm is an accumulation of micro-organisms and their extracellular products forming a structured community on a surface. Biofilm formation on medical devices has severe health consequences as bacteria growing in this lifestyle are tolerant to both host defense mechanisms and antibiotic therapies. However, silver and zinc ions inhibit the attachment and proliferation of immature biofilms. The objective of this study is to evaluate whether it is possible to produce silver and zinc-containing glass polyalkenoate cement (GPC) coatings for medical devices that have antibacterial activity and which may therefore inhibit biofilm formation on a material surface. Two silver and zinc-containing …

Simulation Of Nanostructured Electrodes For Polymer Electrolyte Membrane Fuel Cells, Sanjeev M. Rao, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Aligned carbon nanotubes (CNTs) with Pt uniformly deposited on them are being considered in fabricating the catalyst layer of polymer electrolyte membrane (PEM) fuel cell electrodes. When coated with a proton conducting polymer (e.g., Nafion) on the Pt/CNTs, each Pt/CNT acts as a nanoelectrode and a collection of such nanoelectrodes constitutes the proposed nanostructured electrodes. Computer modeling was performed for the cathode side, in which both multicomponent and Knudsen diffusion were taken into account. the effect of the nanoelectrode lengths was also studied with catalyst layer thicknesses of 2, 4, 6, and 10 μm. It was observed that shorter lengths …

Multiple Radar Data Merging In Hydro-Nexrad, Witold F. Krajewski, Bong Chul Seo, Anton Kruger, Piotr Domaszczynski, Gabriele Villarini, James A. Smith

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Hydro-NEXRAD merging algorithms include two options: (1) data-based merging; and (2) product-based merging. Data-based merging algorithm takes volume scan reflectivity data from all radars involved through preprocessing algorithm that performs volume data quality control, interpolates data to synchronize temporal scale between individual radars, and finally combines data onto a common geographic grid. Reflectivity values for a given location are assigned by a weighting function with respect to the distance from the radar. This single reflectivity field is then converted to rainfall amounts using a user-requested standard approach. In product-based merging algorithm reflectivity data from multiple radars are all converted …

Translating Terms Of The Functional Basis Into Biologically Meaningful Keywords, Hyunmin Cheong, L. H. Shu, Robert B. Stone, Daniel A. Mcadams

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Biology has long been recognized as an excellent source of analogies and stimuli for engineering design. Previous work focused on the systematic identification of relevant biological analogies by searching for instances of functional keywords in biological information in natural language format. This past work revealed that engineering keywords couldn't always be used to identify the most relevant biological analogies, as the vocabularies between biology and engineering are sufficiently distinct. Therefore, a method of identifying biologically meaningful keywords that correspond to engineering keywords was developed. Here, we apply and refine this method by generating biologically meaningful keywords for the terms of …

Secure Virtual Backbone-Based Power Management For Ad Hoc Networks, Hung Yuan Hsu, Ali R. Hurson

Electrical and Computer Engineering Faculty Research & Creative Works

Power saving is a critical issue in wireless ad hoc networks. Many of the existing energy efficient routing protocols utilize the power management feature provided by MAC layer (e.g., IEEE 802.11 PSM). the rationale behind these protocols is to power down (put in sleep) the redundant nodes that do not involve in the packets routing. to keep a low end-to-end latency and preserve the routing fidelity, a group of nodes are selected to constitute a virtual backbone throughout the network. the backbone nodes do not sleep all the time serving for the packets routing while the rest of nodes turn …

Analysis And Design Of Interleaving Multiphase Dc-To-Dc Converter With Input Lc Filter, Kevin Thomas Delrosso

Master's Theses

The future of microprocessors is unknown. Over the past 40 years, their historical trend has been for adopting smaller and more powerful designs that drive the world that we live in today. The state of the microprocessor business today faces a crossroad, wishing to continue on the historical trend of doubling the number of transistors on a chip every 18 months (Moore’s Law) but also facing the realistic task of needing to power these sophisticated devices. With the low voltages and high currents that are required for these microprocessors to operate, it poses a difficult task for the future designers …

Bioflocculation For Control Of Wastewater Pond Microalgae, Daniel Thomas Frost

Master's Theses

Investigates several hypotheses regarding the use of bioflocculation as a harvesting method for wastewater pond microalgae. Research performed on pilot-scale high rate ponds (HRPs) on the California Central Coast.

Comparison Of Electrically Mediated And Liposome-Complexed Plasmid Dna Delivery To The Skin, Loree C. Heller, Mark J. Jaroszeski, Domenico Coppola, Richard Heller

Bioelectrics Publications

BACKGROUND: Electroporation is an established technique for enhancing plasmid delivery to many tissues in vivo, including the skin. We have previously demonstrated efficient delivery of plasmid DNA to the skin utilizing a custom-built four-plate electrode. The experiments described here further evaluate cutaneous plasmid delivery using in vivo electroporation. Plasmid expression levels are compared to those after liposome mediated delivery.

METHODS: Enhanced electrically-mediated delivery, and less extensively, liposome complexed delivery, of a plasmid encoding the reporter luciferase was tested in rodent skin. Expression kinetics and tissue damage were explored as well as testing in a second rodent model.

RESULTS: Experiments …

Modular Multi-Stage Axial Compressor Design, Christopher S. Hemerly

Master's Theses - Daytona Beach

Increasingly, companies are becoming more interested in reducing cost. Recent studies indicate that up to 80% of the Lifecycle costs (LCC) has been embedded in the engine's DNA at the end of the development and design phase. One concept to aid in the cost reduction is the modular design of expensive and development-intensive components, such as multi-stage axial compressors. It is the objective of this approach to utilize a "core" module in all the compressors, thus maximizing commonality and minimizing all relevant development, design, manufacture, procurement, and service costs; these reductions in cost are projected to increase affordability by five-fold. …

"G" And "H" Control Charts And Risk Analysis In The Banking Industry, James L. Bossert

All-Inclusive List of Electronic Theses and Dissertations

This research investigates the utilization of a new control chart in the Banking industry to minimize financial risk. There are processes in the banking industry that do not lend themselves to traditional control chart applications. These processes tend to be high volume. High volume meaning over a million transactions a day and a requirement for high levels of accuracy characterize these processes. The research has looked at these processes and applied the "g" control charts to determine if they provide timely feedback to the banking industry. The value of this research will give the banking industry an opportunity to react …

Modeling Fluid Structure Interaction Over A Flexible Fin Attached To A Naca0012 Airfoil, Srinivasa Ravindra Pantula

Dissertations

Flow separation control is of importance to the performance of air vehicles. Generally, it is desired to postpone separation such that the overall drag is reduced, stall is delayed, lift is enhanced, and pressure recovery is improved. This work explores a new concept of post-stall flow control for airfoils and wings by using a thin flexible fin attached on the upper surface of an airfoil to passively manipulate flow structures in the fully separated flows for drag reduction and lift enhancement. The flow induced oscillations combined with the shape deformations change the overall pressure distribution on the fin, which in …

Atomistic-Based Finite Element Simulation Of Carbon Nanotubes, Yang Yang

Dissertations

Since first found in the form of multi-walled carbon nanotubes (MWNTs) by Iijima(1991), carbon nanotube (CNT) for its outstanding and unique properties have gained overwhelming attentions from across the spectrum of the science and engineering fields. CNTs are structurally perfect, small size, low density, high stiffness, high strength (Qian et al., 2002), and their electronic properties depend on the particular distortion as well as the initial tube diameter and chirality, ranging from narrow-gap or moderate-gap semiconducting to metallic (Pantano et al., 2004b), which can be utilized in nanoscale sensors and devices. These appealing characteristics provide strong drives for the possible …

Flexography Printing Of Silver Based Conductive Inks On Packaging Substrates, Ramesh Chandra Kattumenu

Dissertations

Printing technologies for the production of flexible electronics have gained much interest due to its potential as a means to reduce the complexity and costs of present technology. High volume printing techniques like flexography are of great importance in order to produce rolls of flexible electronics printed directly on paper substrates. The proposed research will be focused on RFID components being in-line printed using flexography printing as the manufacturing platform. The properties of substrates and inks and printing process parameters are evaluated to study their effect on printed traces and RFID antenna. It was found in the study that properties …

A Device For Noninvasive Assessment Of Vascular Impairment Risk In The Lower Extremity, Michael J. Hoffmann, Paul E. Knudson, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

The repeatability and resolution of the clinical gold standard of vascular assessment, the ankle-brachial index (ABI), was compared to that of a new device that dynamically assesses tissue perfusion during external loading utilizing laser Doppler flowmetry. Eight subjects of varying levels of vascular impairment were tested in successive weeks using two different sites on the subject's posterior calf. These new measures included the perfusion decrease as well as the unloading delay during cyclic loading. Some new dynamic tissue perfusion measures demonstrated comparable levels of reproducibility with the ABI (e.g., 10%-20%). Only the unloading delay showed potentially enhanced resolution over ABI …