Engineering Commons^™

Cold-Formed Steel Frame And Beam-Column Design, Andrew T. Sarawit, Teoman Peköz

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

A Summary Of L-Header Designs Using The Aisi Header Design Standard, Dean Peyton

CCFSS Library (1939 - present)

No abstract provided.

An Original Method For Computing Complex Non-Premixed Flows In Chemical Equilibrium, Raphael Cioffl

Master's Theses - Daytona Beach

A novel method for computing chemical equilibrium reactions in three-dimensional reacting fluid flows is introduced in this paper. The originality of the method is that continuity equations are solved for the atomic densities rather than for the molecular species densities, as is the case for non-equilibrium flow calculations. The method is suited for applications to mixing flows in rocket engine combustors, where, due to the typical low convective speed, chemical reaction is best modeled as an equilibrium process. Equilibrium formulations usually describe the flow as a perfect, atomically uniform mix between the fuel and the oxidizer. This assumption tends to …

Acuta Enews August 2003, Vol. 32, No. 8

ACUTA Newsletters

In This Issue

Key Words for the Coming Months.................Walter Czerniak, Northern Illinois University

Wi or Wi Not? Taking Wireless to the Max..................... Kevin Tanzillo, Dux Public Relations

New Additions to Telecommunications Relay Service................. Dave Ostrom, Washington State Univ.

DC Update..................... Whitney Johnson, Retired, Northern Michigan Univ.

Board Report................... John Bradley, Rensselaer Polytechnic lnstitute

Welcome New Members

Fdtd Modeling Of Isotropic Dispersive Magnetic Materials, Jing Wu, Marina Koledintseva, James L. Drewniak, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Numerical analysis using the finite-difference time-domain (FDTD) algorithm with a piecewise linear recursive convolution (PLRC) procedure for linear isotropic dispersive magnetic materials is presented. The frequency dependence of susceptibility used for this algorithm is represented in Debye, narrowband Lorentzian, and wideband Lorentzian forms, depending on the ratio of the resonance frequency and the resonance line width. Some numerical examples along with measurements are provided.

Memory Dimm Dc Power Distribution Analysis And Design, Jingkun Mao, Chen Wang, Giuseppe Selli, Bruce Archambeault, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

DC power bus design is critical in meeting signal integrity (SI) and electromagnetic compatibility (EMC) requirements. A suitable modeling tool is beneficial to evaluate power bus design and develop design guidelines. This paper discusses difficulties met in evaluating the power distribution design on a dual inline memory module (DIMM) board, such as a power bus with arbitrary shape, parasitic inductance associated with vias, and so on. Moreover, some solutions are given in this paper. A simple cavity model with a segmentation method was employed to model a power bus with irregular shapes. The partial element equivalent circuit (PEEC) technique was …

Real-Time Dual Heuristic Programming-Based Neurocontroller For A Turbogenerator In A Multimachine Power System, Ganesh K. Venayagamoorthy, Ronald G. Harley, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Based on Dual Heuristic Programming (DHP), a real-time implementation of a neurocontroller for excitation and turbine control of a turbogenerator in a multimachine power system is presented. The feedback variables are completely based on local measurements. Simulation and real-time hardware implementation on a three-machine system demonstrate that the DHP neurocontroller is much more effective than conventional PID controllers, the automatic voltage regulator, power system stabilizer and the governor, for improving dynamic performance and stability under small and large disturbances.

Evaluation Of Working Capacity For Disadvantaged Business Enterprises (Dbe) For Highway Construction In Kentucky, Fy 2004 Update, Brad W. Rister, Raymond F. Werkmeister, Paul E. Toussaint

Kentucky Transportation Center Research Report

The Kentucky Transportation Center gathered the appropriate information, performed a series of computations and analyses, prepared the attached documentation, and makes the following recommendations to the Kentucky Transportation Cabinet for their DBE goal for Federal Fiscal year 2004 (October 1, 2003 - September 30, 2004).

KTC recommends an overall DBE goal of 9.26%, of which 1.931% is anticipated to be satisfied by race/gender neutral prime contracts, and the resultant 7.33% should established as race/gender conscious subcontracts. The overall DBE goal figures stated here addresses an adjustment of 1.326% for the positive historical goal variance observed for the past eight years.

Evaluation Of Non-Nuclear Density Gauges, David L. Allen, David B. Schultz Jr., David Allen Willett

Kentucky Transportation Center Research Report

For the past several decades, density of freshly laid hot mix asphalt (HMA) mats has been measured by contractors, consultants or governmental agencies using nuclear density gauges. However, use of these devices requires the user to maintain an inordinate amount of records on the use of the equipment. These requirements include calibration and recalibration records, certification records of the operators, records on radiation badges, and periodic testing of the operator’s badges for radiation exposure. In addition, there is always the concern about possible accidents with the gauges that might expose the radiation source to the operators or other bystanders. Because …

Lessons Learned System For Kentucky Transportation Projects, Paul M. Goodrum, Mohammed F. Yasin, Donn E. Hancher

Kentucky Transportation Center Research Report

A system of collecting, archiving, and disseminating lessons learned is a critical component of experienced-based processes, such as the design and construction of roadway and bridges. This report examines the development of a centralized, web-based Lessons Learned System for the Kentucky Transportation Cabinet. The research developed a working prototype of a lessons learned system that functions off of centrally located databases making it easier to administer and update. The Lessons Learned System was designed to accept both text and attachments through file uploads while maintaining relationships between these items of information in terms of a lesson learned. The report describes …

The Use And Performance Of Geogrids In Kentucky, Aric Cowne, Richard Reitenour, David L. Allen, R. Clark Graves

Kentucky Transportation Center Research Report

This report will investigate the history and usage of geogrids, a subfamily of geosynthetics, in Kentucky. The American Society for Testing and Materials (ASTM - 1994) has defined a geosynthetic as a planar product manufactured from a polymeric material used with soil, rock, earth, or other geotechnical-related material as an integral part of a civil engineering project, structure, or system. Geogrids, geosynthetics primarily used for reinforcement, are formed by a regular network of tensile elements with apertures of sufficient size to interlock with surrounding fill material. Geogrids are used as reinforcement by adding tensile strength to a soil matrix, thereby …

Sufficient Conditions Used In Admittance Selection For Force-Guided Assembly Of Polygonal Parts, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Admittance control approaches show significant promise in providing reliable force-guided assembly. An important issue in the development of these approaches is the specification of an appropriate admittance control law. This paper identifies procedures for selecting the appropriate admittance to achieve reliable force-guided assembly of planar polyhedral parts for single-point contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations, then the admittance …

Spontaneous Coherent Pulsations In 3.39-M He–Ne Standing-Wave Laser Oscillators, Pitak Chenkosol, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Spontaneous pulsations similar to the type discovered in 3.51-μm Xe laser oscillators were reported several years ago in 3.39-μm He–Ne lasers, but no numerical interpretation of the He–Ne data has been given. The model for the Xe laser instability is adapted here to the He–Ne system, and the results include direct comparisons between theoretical calculations and published experimental data. Good agreement is obtained for the instability threshold, the pulsation frequencies, and many other features; and unmeasured but potentially useful pulsation characteristics are also readily obtained from the model.

2003 Safety Belt Usage Survey In Kentucky, Kenneth R. Agent, Eric R. Green

Kentucky Transportation Center Research Report

The objective of this study was to establish 2003 safety belt and child safety seat usage rates in Kentucky. The 2003 su rvey continues to document the results after enactment of a statewide mandatory safety belt law in 1994 and safety belt enforcement campaign. Data were collect ed at 200 randomly selected sites spread across Kentucky. Data from the individual sites were combined into a statewide percentage considering roadway functional classification, geographic region, and vehicle miles traveled.

The data show that the usage rate in 2003 (65.5 percent) was higher than that in 2002 (62.0 percent). This compared to 61.9 …

Evaluation Of Kentucky’S “Buckle Up Kentucky: It’S The Law & It’S Enforced” Campaign, Kenneth R. Agent, Eric R. Green, Ronald E. Langley

Kentucky Transportation Center Research Report

The objective of this report was to document the results of the “Buckle Up Kentucky: It’s the Law & It’s Enforced” campaign in Kentucky. The campaign involved a combination of earned media, paid media, and enforcement. The earned media started about three weeks prior to Memorial Day 2003 and continued through the enforcement period. The paid media started about two weeks prior to Memorial Day. The enforcement period was a two-week period including the week before and the week of Memorial Day.

The evaluation of the campaign included documenting the activities associated with the program (publicity and enforcement) and evaluating …

Crash Rates At Intersections, Eric R. Green, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objectives of this study were to develop a database of intersections, match traffic crashes to these intersections, calculate crash rates for various types of intersections, and identify intersections with the highest crash rates. A procedure was used to: a) identify intersections, b) assign crashes to these intersections, c) determine entering traffic volume, d) calculate a crash rate for each intersection, and e) calculate a critical rate factor (CRF) for each intersection.

About 7,000 intersections were identified with almost 19,000 crashes related to these intersections for the three-year period of 2000 through 2002. The analysis identified 428 intersections that had …

Anticipating Emi Using Transfer Functions And Signal Integrity Information, Chen Wang, James L. Drewniak, Jim Nadolny

Electrical and Computer Engineering Faculty Research & Creative Works

Discontinuities in a circuit can lead to signal integrity as well as EMI problems. A method, which efficiently combines full-wave tools and circuit simulators, is proposed herein to analyze the coupling at discontinuities. The proposed method may be applied to practical engineering designs.

Anticipating Vehicle-Level Emi Using A Multi-Step Approach, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen

Electrical and Computer Engineering Faculty Research & Creative Works

A multi-step procedure for anticipating vehicle-level EMI is proposed in this paper. This approach uses multi-conductor transmission line (MTL) modeling to calculate current distributions along the cable bundle. A common-mode circuit is extracted from the MTL modeling, and is employed in full-vehicle full-wave modeling to determine radiation and interference. In this paper, mode-dispersion and mode-conversion phenomena are investigated, and the ambiguous definitions of the common-mode voltage and common-mode impedance are discussed.

Impact Of Esd Generator Parameters On Failure Level In Fast Cmos System, Kai Wang, David Pommerenke, Kai Xiao, Ponniah Ilavarasan, Mike Schaffer, Ramachandran Chundru, Jiu Sheng Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Electrostatic discharge (ESD) generators are used for testing the robustness of electronics towards ESD. Most generators are built in accordance with the IEC 61000-4-2 specifications. It is shown that the voltage induced in a small loop correlates with the failure level observed in an ESD failure test on the systems comprising fast CMOS devices, while rise time and current derivative of the discharge current did not correlate well. The electric parameters are compared for typical and modified ESD generators and the effect on the failure level of fast CMOS electronics is investigated. The consequences of aligning an ESD standard with …

Modeling Issues For Full-Wave Numerical Emi Simulation, Michael A. Cracraft, Xiaoning Ye, Chen Wang, Sandeep K. R. Chandra, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

In electromagnetic modeling, agreement between modeling and measurements is a common goal. There are questions that define every model. What is to be modeled? How is it going to be modeled? At what scale is it to be modeled? Through sample results and discussion, this paper addresses some general and some specific elements of model veracity. Through determination, numerical models can certainly be pushed to match any measured results. However, in the end the question that this paper addresses is not necessarily "How good can this model be?" as it is "Is this model good enough?".

Online Identification Of Turbogenerator's Dynamics Using A Neuro-Identifier, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of modern power systems highlights the need for effective system identification techniques for the successful control of power system. This paper proposes a robust continually online trained neuroidentifier to predict the outputs of turbogenerator - terminal voltage and speed deviation. The inputs to the neuro-identifier are the changes of the plant's outputs and plant's inputs. It overcomes the drawback of calculating deviation signals from reference signals for different operating points in previous work. Simulation results show that the neuro-identifier can provide accurate identification under different operating conditions. Furthermore, the neuro-identifier can learn the dynamics of the system …

Fdtd Method Capable Of Attaching Rectangular Domains, Kai Xiao, David Pommerenke, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A finite-difference time-domain (FDTD) method capable of attaching rectangular computational domains is proposed herein. The aim of this approach is to reduce the size of computational domain according to the geometry of the modeled structure so as to reduce the simulation time with keeping precision of the result in an acceptable range. A multigrid algorithm is applied on the attaching interface between two rectangular domains so that different resolution can be achieved in different domains.

Reconstruction Of The Parameters Of Debye And Lorentzian Dispersive Media Using A Genetic Algorithm, Jianmin Zhang, Marina Koledintseva, Giulio Antonini, James L. Drewniak, Konstantin Rozanov, Antonio Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

A method for reconstruction of the parameters of the Debye or Lorentzian dispersive media is proposed. In this method, S-parameters of a simple parallel-plate fixture filled with the dispersive medium are measured and modeled using the transmission line equations, provided a single TEM mode propagating in this parallel-plate waveguide. The genetic algorithm is used for searching the parameters of the dispersive medium by means of minimizing the discrepancy between the measured and modeled S-parameters. The results are verified using the full-wave FDTD modeling technique.

Modeling Of Short-Gap Esd Under Consideration Of Different Discharge Mechanisms, S. Bonisch, Wilifried Kalkner, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Simulation of short gap electrostatic discharge (ESD) in air needs to consider two processes: a surface process and an avalanche process. Two models, a phenomenological approach and a physical approach, considering both discharge processes are proposed for the simulation of short-gap ESD. A new mathematical derivation for the modeling of the surface process is discussed in detail. A new technique to combine surface and avalanche process models is described. Measured and simulated data based on short-gap ESD are provided and compared. Advantages and drawbacks of the proposed models are discussed. Attained results should help to optimize ESD testing.

Quantifying The Effects On Emi And Si Of Source Imbalances In Differential Signaling, Chen Wang, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Imbalances in differential signaling can introduce common-mode components, resulting in signal integrity (SI) problems as well as EMI problems. Three-port mixed-mode S-parameters are employed to quantify the impacts on EMI. The EMI problems caused by delay skew and slew rate skew are investigated.

Evaluation Of The Distribution Of Taguchi's Signal-To-Noise Ratio And The Effectiveness Of The Signal-To-Noise Ratio For Detecting Changes In The Mean And/Or Variance, Jinsuk Lee

Masters Theses

The concept of parameter design developed by Taguchi to achieve robust engineering is widely promoted in industry as a means to design a product whose output is largely immune to noise in the system. Taguchi has used the signal-to-noise (S/N) ratio to summarize measures over the noise factor settings at the parameter design and to allow control of the experiment.

The objectives of this investigation are: 1) to infer distributions of S/N ratios (lower-the-better S/N, higher-the-better S/N, and nominal-the-best SIN), and 2) to determine the effectiveness of the S/N ratio as a means for identifying changes in the mean and …

Elastic Wave Propagation And Scattering In Solids With Uniaxially Aligned Cracks, Liyong Yang, Joseph A. Turner

Nebraska Center for Materials and Nanoscience: Faculty Publications

In this article, elastic wave propagation and scattering in a solid medium permeated by uniaxially aligned penny-shaped microcracks are studied. The crack alignment refers to the case in which the unit normals of all cracks are randomly oriented within a plane of isotropy. The analysis is restricted to the limit of the noninteraction approximation among individual cracks. Explicit expressions for attenuations and wave speeds of the shear horizontal, quasilongitudinal, and quasishear vertical waves are obtained using stochastic wave theory in a generalized dyadic approach. The ensemble average elastic wave response is governed by the Dyson equation, which is solved in …

Modeling Carrier Behavior In Sequential Auction Transportation Markets, Miguel Andres Figliozzi, Hani S. Mahmassani, Patrick Jaillet

Civil and Environmental Engineering Faculty Publications and Presentations

Online markets for transportation services, in the form of Internet sites that dynamically match shipments (shippers? demand) and transportation capacity (carriers? offer) through auction mechanisms are changing the traditional structure of transportation markets. A general framework for the study of carriers? behavior in a sequential auction transportation marketplace is provided. The unique characteristics of these marketplaces and the sources of difficulty in analyzing the behavior of these marketplaces are discussed. Learning and behavior in a sequential Vickrey auction marketplace is analyzed and simulated. Some results and the overall behavioral framework are also discussed.

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics - Phase Three, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The proposed work will combine chemical kinetics and hydrodynamics in target and test-loop lead-bismuth eutectic (LBE) systems to model system corrosion effects. This approach will result in a predicative tool that can be validated with corrosion test data, used to systematically design tests and interpret the results, and provide guidance for optimization in LBE system designs. The task includes two subtasks. The first subtask is to try to develop the necessary predictive tools to be able to predict the levels of oxygen and corrosion products close to the boundary layer through the use of Computational Fluid Dynamics (CFD) modeling. The …

Volumetric Growth Of Thermoelastic Materials And Mixtures, Stephen M. Klisch, Anne Hoger

Mechanical Engineering

The proteoglycan and collagen constituents of cartilage serve distinct mechanical roles. Changes to the mechanical loading conditions during cartilage growth lead to changes in the concentrations of these molecules and, consequently, the mechanical properties. The main aim of this paper is to present a theory that can describe the mechanical aspects of cartilage growth. The model for cartilage growth is based on a general thermomechanical theory for a mixture of an arbitrary number of growing elastic constituents and an inviscid fluid. Our development of a growth mixture theory is accomplished in two steps. First, the thermodynamics of growing elastic materials …