Digital Commons Network^™

Comparison Of 3-, 5-, And 6-Phase Machines For Automotive Charging Applications, B. Zhang, Hua Bai, Walter Eversman, Ronald J. Krefta, Duane J. Buening, Steven Pekarek, Gregory R. Holbrook

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, the performance of a 5-phase claw-pole machine/converter system is compared with those of 3-phase and 6-phase systems of the same volume. It is shown that the acoustic output of the 5-phase machine compares favorably with that of the 6-phase machine and is much lower than that of the 3-phase machine over a majority of the operating range. In addition, the output current produced by the 5-phase machine Is, in general, 6-8% higher than those of the 3-phase and 6-phase machines. These results suggest that for maximizing power density while minimizing cost and acoustic noise, 5-phase machines provide …

A Single-Element Tuning Fork Piezoelectric Linear Actuator, J. Satonobu, K. Nakamura, S. Ueha, Daniel S. Stutts, James R. Friend

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper describes the design of a piezoelectric tuning-fork, dual-mode motor. The motor uses a single multilayer piezoelectric element in combination with tuning fork and shearing motion to form an actuator using a single drive signal. Finite-element analysis was used in the design of the motor, and the process is described along with the selection of the device's materials and its performance. Swaging was used to mount the multilayer piezoelectric element within the stator. Prototypes of the 25-mm long bidirectional actuator achieved a maximum linear no-load speed of 16.5 cm/s, a maximum linear force of 1.86 N, and maximum efficiency …

Approximate Dynamic Programming Based Optimal Neurocontrol Synthesis Of A Chemical Reactor Process Using Proper Orthogonal Decomposition, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The concept of approximate dynamic programming and adaptive critic neural network based optimal controller is extended in this study to include systems governed by partial differential equations. An optimal controller is synthesized for a dispersion type tubular chemical reactor, which is governed by two coupled nonlinear partial differential equations. It consists of three steps: First, empirical basis functions are designed using the "Proper Orthogonal Decomposition" technique and a low-order lumped parameter system to represent the infinite-dimensional system is obtained by carrying out a Galerkin projection. Second, approximate dynamic programming technique is applied in a discrete time framework, followed by the …

Hierarchical Optimal Control Of A Turning Process - Linearization Approach, Anand Dasgupta, B. Pandurangan, Robert G. Landers, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Machining process control technologies are currently not well integrated into machine tool controllers and, thus, servomechanism dynamics are often ignored when designing and implementing process controllers. In this paper, a hierarchical controller is developed that simultaneously regulates the servomechanism positions and cutting forces in a lathing operation. The force process and servomechanism system are separated into high and low levels, respectively, in the hierarchy. The high level goal is to maintain a constant cutting force to maximize productivity while not violating a spindle power constraint. This goal is systematically propagated to the lower level and combined with the low level …

From Realism To Minimalism And Back Again: A Comparison Of Anton Chekhov And Raymond Carver, Olga Olegovna Cherchesova

Dissertations and Theses @ UNI

This thesis involves a comparison of two short story writers: Anton Chekhov and Raymond Carver. Anton Chekhov has been acknowledged as one of the most significant influences upon the American literature; in particular, he had a strong personal and professional influence on Raymond Carver. Examination of these authors' works traces the tradition of literary inheritance and the development of the short story genre itself in the twentieth century. This thesis explores the survival of Chekhovian narrative tradition in American postmodern short story as epitomized in the work of Raymond Carver.

Breaking The Stereotypes: Influences And Characteristics Of Academically Talented Women, Joy Leigh Daggs

Dissertations and Theses @ UNI

I was in fifth grade when I heard the word "gifted" for the first time. I had little idea what it meant, but once I was identified that way, my life as a student began to change. I was suddenly expected to perform at my highest level with very little room for error. I learned about the expectations of my performance from my peers, teachers, and parents. They sent me very clear messages about how I was to perform as an academically talented woman. My experience has shaped my research interest for this thesis. In this thesis, I will explore …

Modeling Fracture In Laminated Automotive Glazing Impacted By Spherical Featureless Headform, Lokeswarappa R. Dharani, S. R. Mettu, S. Zhao, S. D. Barbat, L. Chai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laminated glass consisting of two soda lime glass plies adhered by a polyvinyl butyral interlayer (PVB) is used for automotive glazing. This paper describes the application of a dynamic, nonlinear finite element method to investigate the failure modes of a laminated glass subjected to low-velocity impact with a spherical head form. Crack type, crack location and crack initiation time are evaluated using the maximum principal stress and J-integral criterion. Failure occurred due to flexural stresses and not bearing stresses. the first crack always initiated at the center of the outer impacted ply and PVB interface, and later on the exterior …

Multidimensional, Time-Accurate Cfd Simulation Of Adsorption/Desorption In A Carbon Canister, Xingyan Bai, Kakkattukuzhy M. Isaac, D. Klein, R. Banerjee, J. Edson, W. Breig, L. Oliver

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Computational fluid dynamics simulations of fixed-bed adiabatic adsorption/desorption processes are presented in this paper. Linear driving force model is used for heat and mass transfer rates. a two-dimensional cylindrical canister and three-dimensional automotive production canister geometry are used to study the adsorption/desorption processes of carbon dioxide in helium carrier gas on Norit B4 activated carbon. the two-dimensional results compare well with the results of Hwang et al. [1]. Computational results as breakthrough curve, adsorption amount and temperature profiles are provided. Results show that non-adiabatic model should be used to fully utilize the activated carbon bed capacity prior to breakthrough. Copyright …

Enhancement Of Output Electric Power In Switched Reluctance Generators, S. Dixon, Babak Fahimi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a new switching strategy to increase overall productivity for a switched reluctance generator (SRG). This paper presents the idea of using an intermediate freewheeling mode to boost the magnetizing current without taking additional energy from the DC link. Once the optimal motional back-EMF is established, then both switches will be turned off. Although during the freewheeling process no electricity is generated, by proper timing of each region an overall enhancement in productivity of the SRG is achieved. to demonstrate the practicality of the proposed technique, simulation results are provided. These simulations take into account the switching losses …

Million City Traveling Salesman Problem Solution By Divide And Conquer Clustering With Adaptive Resonance Neural Networks, Samuel A. Mulder, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The Traveling Salesman Problem (TSP) is a very hard optimization problem in the field of operations research. It has been shown to be NP-complete and is an often-used benchmark for new optimization techniques. One of the main challenges with this problem is that standard, non-AI heuristic approaches such as the Lin-Kernighan algorithm (LK) and the chained LK variant are currently very effective and in wide use for the common fully connected, Euclidean variant that is considered here. This paper presents an algorithm that uses adaptive resonance theory (ART) in combination with a variation of the Lin-Kernighan local optimization algorithm to …

Optimization Of An Automotive Generator Using Evolutionary Programming, A. Koenig, J. Williams, Steven Pekarek

Electrical and Computer Engineering Faculty Research & Creative Works

One of the primary design requirements of automotive generation systems is maximizing power density subject to the constraint of minimizing overall system cost. However, with progress made in reduction of automotive drive train noise, the torque ripple of the generator has been found to be a dominant noise source under idle conditions at high electrical load. Thus, an added design constraint is the minimization of torque ripple produced by the machine. in order to meet these objectives, numerical tools have been developed to automate the design process. a primary tool is an evolutionary algorithm that has been integrated within a …

Welcome To The Special Issue: The Best Of The Best, Donald C. Wunsch, Mike Hasselmo, De Liang Wang, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

The Implementation Of Behavior Management Strategies In An Elementary School Setting, Leary B. Adams Jr.

Abraham S. Fischler College of Education ETD Archive

Action research methods were used to examine the effects of behavior management strategies on the rate of discipline referrals at Twin Lakes Elementary School, an inner-city elementary school in Nevada. A review of archival records revealed that during the 3-year period from 1997 through 2002, the number of discipline referrals at Twin Lakes Elementary School increased from 73 to 170 referrals while enrollment showed no significant increase.

Some possible causes of the large number of discipline referrals were identified as: (a) inconsistencies in the referral process, (b) lack of support for teachers experiencing difficulty with student misbehavior, (c) lack of …

A Question Of Sanity: Women And In/Sanity In Bessie Head’S A Question Of Power And Sylvia Plath’S The Bell Jar, Amanda Lynn Graeber

Dissertations and Theses @ UNI

The use of female mental illness in fiction has previously been characterized as a subversive act. Theorists such as Juliet Mitchell, Susan Gubar, and Sandra Gilbert have advocated the use of madness as a way of protesting patriarchal systems and language. Female madness in many cases has been viewed not only as a conscious choice, but as an option that is preferable to sanity. In their view, mental illness is an embodiment of a woman's rejection of the patriarchal order. I would suggest that mental illness is actually about powerlessness. The madwoman is placed in a space outside of normal …

Parents, Educators, Law Enforcement, And Participation In Delinquent Behavior: Gender Socialization And Views Of Life Changes, Jolie Marie Imler

Dissertations and Theses @ UNI

The task of the proposed research is to determine the extent parents, educators, law enforcement, and participation in delinquent behavior influence responses of youth toward their hopefulness for the future and likelihood of attending college and whether the relationships differ by gender. Using gender socialization, social capital, and labeling theories as theoretical backgrounds, it is anticipated that contradictory socialization patterns, gendered access to social capital, and labels influence the resources and responses of female juveniles when considering hopefulness for the future and the likelihood of attending college. The proposed study will use secondary data comprised of youth either adjudicated delinquent …

A Graduate Piano Recital, Jennifer Iverson

Dissertations and Theses @ UNI

Jennifer Iverson, pianist, presented a graduate recital at 6:00 p.m. on Friday, April 18, 2003 in Davis Hall at the Gallagher-Bluedorn Performing Arts Center on the University of Northern Iowa campus. The recital was given in partial fulfillment of the requirements of the Master of Music degree in Piano Performance and Pedagogy. The program included works by Ludwig van Beethoven, Franz Schubert, Maurice Ravel, Lili Boulanger, and Arnold Schonberg. The following paragraphs provide commentary on the programmed pieces.

High Precision Wavelength Measurements Of Qed-Sensitive Forbidden Transitions In Highly Charged Argon Ions, I. Draganić, J. R. Crespo López-Urrutia, Robert D. Dubois, S. Fritzsche, V. M. Shabaev, R. Soria Orts, I. I. Tupitsyn, Y. Zou, J. Ullrich

Physics Faculty Research & Creative Works

We present the results of an experimental study of magnetic dipole ([Formula presented]) transitions in highly charged argon ions (ArX, ArXI, ArXIV, ArXV) in the visible spectral range using an electron beam ion trap. their wavelengths were determined with, for highly charged ions, unprecedented accuracy up to the sub-ppm level and compared with theoretical calculations. the QED contributions, calculated in this Letter, are found to be 4 orders of magnitude larger than the experimental error and are absolutely indispensable to bring theory and experiment to a good agreement. This method shows great potential for the study of QED effects in …

Postcollisional Decay In Ne Multiple Ionization By H2+ Ions In Breakup Collisions, M. M. Sant'anna, H. Luna, Antonio C. Santos, C. Mcgrath, M. B. Shah, E. G. Cavalcanti, G. M. Sigaud, E. C. Montenegro

Physics Faculty Research & Creative Works

We measured the Ne^q+ charge-state yield distribution for Ne atoms multiply ionized by 1-MeV/amu H₂⁺ in coincidence with the final state of the projectile, for both breakup and Non breakup channels. Measurements with 1-MeV H⁺ projectiles were also performed. While the H₂⁺ Non breakup channel produces results similar to equal-velocity proton or electron projectiles, the breakup channels lead to a charge-state yield distribution very close to the known Ne 2s^-1 post collisional decay distribution, measured through photoionization [T. A. Carlson, W. E. Hunt, and M. O. Krause, Phys. Rev. 151, 41 (1966)]. This …

Target Z Dependence And Additivity Of Cross Sections For Electron Loss By 6-Mev/Amu [Formula Presented] Projectiles, R. L. Watson, Yong Peng, V. Horvat, G. J. Kim, Ronald E. Olson

Physics Faculty Research & Creative Works

The dependence of electron loss by 6-MeV/amu Xe¹⁸⁺ on target atomic number was investigated by measuring single-collision cross sections for loss of one to eight electrons in targets of the noble gases He, Ne, Ar, Kr, and Xe. the total-electron-loss cross sections were found to increase linearly with target atomic number, but an abrupt slope change was observed to occur between Ne and Kr. Calculated total-loss cross sections obtained using the n-body classical trajectory Monte Carlo method were in good agreement with the measurements. the dependence of the individual cross sections on the number of electrons lost was reasonably …

The Effects Of Music Paired With Story Book Reading On Kindergarten And First Grade Children’S Comprehension Of Narrative Text, Karen Kay Fatka

Dissertations and Theses @ UNI

The purpose of this study was to investigate the effects of music paired with story book reading on young children's comprehension of narrative text. More specifically, children's abilities to verbally retell stories, answer questions regarding explicit text based story facts, and attention levels were compared when stories were orally read or presented through audio-recorded sung versions of each story. Thirty kindergarten and first grade students who exhibited a speech and/or language impairment, had a history of a speech and/or language impairment, or were at-risk for reading difficulties participated in the study. Subjects were identified through a local university speech and …

Detecting And Representing Relevant Web Deltas In Whoweda, Sanjay Kumar Madria, Wee Keong Ng, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

In this paper, we present a mechanism for detecting and representing changes, given the old and new versions of a set of interlinked Web documents, retrieved in response to a user''s query. In particular, we show how to detect and represent Web deltas, i.e., changes in the Web documents that are relevant to a user''s query in the context of our Web warehousing system called WHOWEDA (Warehouse of Web Data). In WHOWEDA, Web information is materialized views stored in Web tables in the form of Web tuples. These Web tuples, represented as directed graphs, can be manipulated using a set …

Combining Evolving Neural Network Classifiers Using Bagging, Sunghwan Sohn, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

The performance of the neural network classifier significantly depends on its architecture and generalization. It is usual to find the proper architecture by trial and error. This is time consuming and may not always find the optimal network. For this reason, we apply genetic algorithms to the automatic generation of neural networks. Many researchers have provided that combining multiple classifiers improves generalization. One of the most effective combining methods is bagging. In bagging, training sets are selected by resampling from the original training set and classifiers trained with these sets are combined by voting. We implement the bagging technique into …

Cooperative Cleaning For Distributed Autonomous Robot Systems Using Fuzzy Cognitive Maps, H. Subramanian, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Cooperative Autonomous Cleaning is a simple challenge that can be implemented with the help of Fuzzy Cognitive Maps (FCM) by simulating the actual thinking process of the human. The human mind organizes its thoughts in priorities and this feature could be exploited well if a priori knowledge of the system exists. This technique has been attempted here for a DARS.

Web Personalization Using Neuro-Fuzzy Clustering Algorithms, Kartik Menon, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Different users have different needs from the same web page and hence it is necessary to develop a system which understands the needs and demands of the users. Web server logs have abundant information about the nature of users accessing it. In this paper we discussed how to mine these web server logs for a given period of time using unsupervised and competitive learning algorithm like Kohonen''s self organizing maps (SOM) and interpreting those results using Unified distance Matrix (U-matrix). These algorithms help us in efficiently clustering users based on similar web access patterns and each cluster having users with …

An Intelligent Early Warning System For Software Quality Improvement And Project Management, Xiaoqing Frank Liu, Gautam Kane, Monu Bambroo

Computer Science Faculty Research & Creative Works

One of the main reasons behind unfruitful software development projects is that it is often too late to correct the problems by the time they are detected. It clearly indicates the need for early warning about the potential risks. In this paper, we discuss an intelligent software early warning system based on fuzzy logic using an integrated set of software metrics. It helps to assess risks associated with being behind schedule, over budget, and poor quality in software development and maintenance from multiple perspectives. It handles incomplete, inaccurate, and imprecise information, and resolve conflicts in an uncertain environment in its …

Sequence Dependent Mobility Of Short Oligonucleotides In Free-Solution Electrophoresis, James D. Sterling, Eve F. Fabrizio, Ali Nadim

Business and Information Technology Faculty Research & Creative Works

No abstract provided.

Query-Based Learning For Aerospace Applications, Donald C. Wunsch, Emad W. Saad, J. J. Choi, J. L. Vian

Electrical and Computer Engineering Faculty Research & Creative Works

Models of real-world applications often include a large number of parameters with a wide dynamic range, which contributes to the difficulties of neural network training. Creating the training data set for such applications becomes costly, if not impossible. In order to overcome the challenge, one can employ an active learning technique known as query-based learning (QBL) to add performance-critical data to the training set during the learning phase, thereby efficiently improving the overall learning/generalization. The performance-critical data can be obtained using an inverse mapping called network inversion (discrete network inversion and continuous network inversion) followed by oracle query. This paper …

Smart Bridges With Fiber-Optic Sensors, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

This article describes an approach to bridge improvements that uses smart structures, introduces key technologies for health monitoring systems based on fiber optics and gives an overview of two instrumented bridges. A sensing system in one application monitors general performance and health of the structure, while the system in a second application interrogates the behavior of a major structural repair.

Statistical Simulation Models For Rayleigh And Rician Fading, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu

Electrical and Computer Engineering Faculty Research & Creative Works

New simulation models are proposed for Rayleigh and Rician fading channels. First, the statistical properties of Clarke's fading model with a finite number of sinusoids are analyzed. An improved Clarke's model is then proposed for the simulation of Rayleigh fading channels. Based on this improved Rayleigh fading model, a novel simulation model is proposed for Rician fading channels. The new Rician fading model employs a zero-mean stochastic sinusoid as the specular (line-of-sight) component, in contrast to all existing Rician fading simulators that utilize a non-zero mean deterministic specular component. The statistical properties of the proposed Rician fading model are analyzed …

The Development Of A Closed-Form Expression For The Input Impedance Of Power-Return Plane Structures, Minjia Xu, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

In multilayer printed circuit boards, the noise on the power bus is influenced by the impedance between the power and ground planes. Power-bus noise estimates require an accurate estimate of the power-bus input impedance. This paper develops a closed-form estimate of the input impedance for circular power-return plane structures. When the structure is lossy (e.g., boards employing embedded capacitance or densely populated boards), the energy reflected from the board edge does not significantly affect the input impedance. In general, the expressions developed here for circular structures can be used to estimate the impedance of lossy power-return plane structures of any …