Digital Commons Network^™

Excitation Of The Whispering-Gallery-Modes At The Shielded Hemispherical Dielectric Resonator, Sergey Kharkovsky, V. V. Kutuzov, A. E. Kogut, V. A. Solodovnik

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Microwave Filtering Of Unwanted Oscillations On Base Of Hexagonal Ferrite Composite Thick Films, Marina Koledintseva, Alexander A. Kitaytsev, Andrey A. Shinkov

Electrical and Computer Engineering Faculty Research & Creative Works

The paper is aimed at the design of waveguide filters of lower frequencies using composite thick films (CTF) made of high-anisotropy polycrystalline hexagonal ferrite powders. Theoretical and experimental results describing the possibility of forming the desired frequency characteristic of the filters are presented

Millimeter Wave Signals Detection By Means Of Monocrystal Hexagonal Ferrite Ellipsoid, Marina Koledintseva, Alexander A. Kitaytsev

Electrical and Computer Engineering Faculty Research & Creative Works

Stable nonlinear resonance effects (SNLREs) have been already studied in crystallographically "isotropic" ferrogarnet ferrite resonators (FR), employed as microwave detectors in the frequency range of 300 MHz to 30 GHz. Application of prospective hexagonal monocrystal ferrites with large field of crystallographic magnetic anisotropy leads to the possibility of a gyromagnetic converter (GC) design for mm waveband (from 30 to 200 GHz) without massive external magnets. This paper deals with the analysis of a more general case with taking into account both crystallographic and form anisotropy as well as the arbitrary orientation of the main crystallographic axis with respect to the …

Deuterium Nmr Of Adsorbed Poly(Methyl Acrylate)-D₃, Frank D. Blum, Wuu-Yung Lin

Chemistry Faculty Research & Creative Works

The dynamics of polymers at interfaces are important in a variety of applications, especially where those applications depend on the mechanical or surface properties. Unfortunately, the surface properties of interfacial species like polymers used in composites are not easily measured macroscopically. Microscopic techniques, especially spectroscopic ones, have been successful. In our laboratory we have been successful in applying NMPR to determine the behavior of absorbed polymers. NMR has several advantages for this kind of study, the principal ones being that it can be used on opaque materials, different nuclei can be used as probes, and interfacial material can sometimes be …

Structural And Magnetic Properties Of Rsr₂Fe₃O₉ (R=La, Y, Pr, And Gd), I. Felner, I. Nowik, A. Mehta, Rajvir Singh, William B. Yelon, V. P. S. Awana, S. X. Dou, Satish K. Malik, A. V. Narlikar

Chemistry Faculty Research & Creative Works

No abstract provided.

Designing Power Bus Decoupling For Cmos Devices, S. Radu, Richard E. Dubroff, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

The adequacy of the DC power bus decoupling for CMOS devices can be determined if the effective board decoupling capacitance, the CMOS load capacitance, the CMOS power dissipation capacitance, the switching time, and the allowable bus noise voltage are known. A simple method is presented for estimating the effective decoupling capacitance. The load and power dissipation capacitance values are shown analytically and experimentally to be closely related to the transient current. The transient current and switching time are used to estimate the transient noise voltage on the power bus

Biological Fixed-Film Systems, Mark W. Fitch, Natalie Pearson, Gene Richards, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Natural Treatment And On-Site Processes, Kevin D. White, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Making Concrete Less Abstract, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

CE 3 13 is a second level properties of concrete lecture course. In an effort to make it appear less abstract to the students, over the course of several semesters several learning strategies were tried, including journaling, muddiest point, entering the academy, role playing, bookends-on-a-lecture, and hands-on lab projects. Most recently, an emphasis on short writing-to-learn papers, a problems-based stance, and an integrated lab project was used. Student evaluations indicated that the lab projects and the increased writing was of significant benefit in promotion of learning.

The Evolution Of Chiral Stationary Phases For Liquid Chromatography, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The development of effective chiral stationary phases (CSPs) and separation strategies for the liquid chromatographic (LC) resolution of enantiomers has been beneficial to many scientific disciplines. Over the last decade the number and type of CSPs has expanded tremendously. Not only have new classes of chiral selectors been introduced, but also many of the first CSPs have been changed and/or improved. The second or third generation of a CSP often can be different from the original. This can be confusing and intimidating to someone just entering the area of LC enantiomeric separations. Fortunately, all CSPs can be categorized in one …

Kurt Mislow Honorary Issue Of Chirality, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

No abstract provided.

Pressure Induced Reversal Of The Volume Expansion Caused By Interstitial Nitrogen In Nd2fe17n3, G. K. Marasinghe, William Joseph James, P. C. Ezekwenna, H. Luo, W. B. Yelon, Y. Zhao, R. B. Von Dreele, M. Ellouze, Ph L'Héritier

Chemistry Faculty Research & Creative Works

Crystallographic properties of Nd2Fe17N3 have been investigated using powder neutron diffraction techniques at pressures up to 7.3 GPa. With increasing pressure, the unit cell volume of Nd 2Fe17N3 decreases almost linearly at a rate of 6.1 Å3/GPa without undergoing a phase transformation or expelling the interstitial nitrogen atoms. The observed rate of contraction corresponds to a bulk modulus of 1.4x1011 N/m2 for Nd2Fe17N3. The unit cell volume of Nd 2Fe17N3 at 7.3 GPa is approximately equal to that of Nd2Fe17 at atmospheric pressure. Even though the unit cell of Nd2Fe17 expands anisotropically due to nitrogenation, contraction of the Nd2Fe17N3 unit …

An Improved Method For Incorporating Magnetic Saturation In The Q-D Synchronous Machine Model, Keith Corzine, Brian T. Kuhn, S. D. Sudhoff, H. J. Hegner

Electrical and Computer Engineering Faculty Research & Creative Works

An improved technique for incorporating saturation into the q-d axis model (Park''s model) of a synchronous machine is proposed. By choosing magnetizing flux linkage as a state variable, iterative procedures required by traditional methods are avoided. The saturation function is represented by an arctangent function which has some distinct advantages over polynomial representations and look-up tables. In particular, the parameters of the proposed function all have physical significance and the proposed function is defined over an infinite range of flux linkage. The model is verified for steady-state and transient conditions using a laboratory synchronous machine-rectifier system similar to those commonly …

Dc Link Stabilized Field Oriented Control Of Electric Propulsion Systems, Keith Corzine, S. D. Sudhoff, Steven F. Glover, H. J. Hegner, H. N. Robey

Electrical and Computer Engineering Faculty Research & Creative Works

Induction motor based electric propulsion systems can be used in a wide variety of applications including locomotives, hybrid electric vehicles, and ships. Field oriented control of these drives is attractive since it allows the torque to be tightly and nearly instantaneously controlled. However, such systems can be prone to negative impedance instability of the DC link. This paper examines this type of instability and sets forth a readily implemented albeit nonlinear control strategy to mitigate this potential problem.

Rose Ausländer (1901-1988): Austria-Hungary/Germany, Kathrin M. Bower

Languages, Literatures, and Cultures Faculty Publications

Rose Ausländer was born Rosalie Beatrice Scherzer on 11 May 1901 into a German-speaking Jewish family. She spent her childhood in Czernowitz, the capital of Bukovina, a province of the Austro-Hungarian Empire. After World War I, Bukovina was incorporated into Romania, and at the end of World War II was annexed by the Soviet Union. Rosalie Scherzer studied literature and philosophy at the university in Czernowitz but never completed a degree, largely because of the family's poverty after her father's death in 1920. To help alleviate this economic situation, she emigrated to the United States in 1921 with lgnaz Ausländer. …

Methods Of Preparing Three-Dimensional, Macroscopic Assemblages Of Carbon Fibrils And The Products Obtained Thereby, Hyperion Catalysis International, Inc., Howard Tennent, Robert W. Hausslein, Nicholas Leventis, David Moy

Chemistry Faculty Research & Creative Works

A method of making randomly oriented carbons fibrils having a cylindrical constant diameter with c-axes perpendicular to their cylindrical axis, which are free of pyrolytically deposited carbon, with a diameter of between 3.5 and 70 nanometers, by dispersing carbon fibrils in a medium and separating them from the medium, by filtration or evaporation to form a porous mat or sheet.

Substroke Matching By Segmenting And Merging For Online Korean Cursive Character Recognition, Chang-Soo Kim, Kang Ryoung Park, Byung Hwan Jun, Jaihie Kim

Electrical and Computer Engineering Faculty Research & Creative Works

The Korean character is composed of several alphabets in two-dimensional formation and the total number of Korean characters exceeds eleven thousand. Therefore, the previous approaches to Korean cursive characters pay most of their attention to segmenting a character into alphabets accurately. However, it is difficult because the boundaries of alphabets are not apparent in most cases. We propose an alphabet-based method without assuming accurate alphabet segmentation. In the proposed method, a cursive character is segmented into substrokes by a set of segmenting conditions. Then it is matched with the reference substrokes generated from alphabet models and ligatures by segmenting and …

The General Approximation Theorem, Donald C. Wunsch, Alexander N. Gorban

Electrical and Computer Engineering Faculty Research & Creative Works

A general approximation theorem is proved. It uniformly envelopes both the classical Stone theorem and approximation of functions of several variables by means of superpositions and linear combinations of functions of one variable. This theorem is interpreted as a statement on universal approximating possibilities ("approximating omnipotence") of arbitrary nonlinearity. For the neural networks, our result states that the function of neuron activation must be nonlinear, and nothing else

Genetic Algorithm Development For Multiobjective Optimization Of Structures, Franklin Y. Cheng, Dan Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Genetic algorithms (GAs) have the characteristic of maintaing a population of solutions and can search in a parallel manner for many nondominated solutions. These features coincide with the requirement of seeking a Pareto optimal set in a multiobjective (multicriteria, vector) optimization problem. The retionale for multiobjective optimization via GAs is that at each generation, the fitness of each individual is defined according to its nondominated property. Because nondominated individuals are assigned the highest fitness values, the convergence of a population will go th the nondominated zone: the Pareto optimal set. Based on this concept, a Pareto, GA, whose goal is …

Contribution Of Externally Bonded Frp To Shear Capacity Of Rc Flexural Members, Ahmed Khalifa, William J. Gold, Antonio Nanni, M. I. Abdel Aziz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fiber reinforced polymer (FRP) materials are continuing to show great promise for use in strengthening reinforced concrete structures. These materials are an excellent option for use as external reinforcing because of their light weight, resistance to corrosion, and high strength. Externally bonded FRP sheets have been used to increase moment capacity of flexural members and to improve confinement in compression members. Investigations into the use of externally bonded FRP sheets for shear strengthening have also been conducted and have been shown to be viable. The objectives of this study were to review the current research on shear strengthening with FRP …

The Structural Behavior Of Homogeneous And Hybrid Stub Columns Under Dynamic Loading Conditions, Chi Ling Pan, Wei Wen Yu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

It has been recognized that the mechanical properties of sheet steels and the structural strength of cold-formed steel members can be influenced by strain rate. For studying the local and postbuckling behavior of the stiffened and unstiffened compression elements under dynamic loading condition, 97 stub columns which were assembled from the same material have been tested under different strain rates. In order to study the structural behavior of hybrid cold-formed stub columns, a total of 144 specimens were investigated. In addition, 52 drop silo tests of stub columns were conducted at General Motors Corporation (GM). The results showed that the …

Optimizing Multiagent, Multi-Injected Swell Modifier, Marshall B. Addison, Thomas M. Petry

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Interactions of expansive clay soils with transportation facilities have caused billions of dollars of damage. In the process of determining agents and methodologies to overcome expansive clay behavior, multiple injections of chemical agents into the subgrade to modify clay behavior are most promising. A study was conducted to optimize a potassium-rich solution of four parts. The modifying solution has been injected into expansive clay subgrades with success since the early 1970s. A laboratory methodology was developed to inject specimens multiple times and to conduct swell tests. Screening tests were conducted to evaluate linear effects that each of the four constituents …

Hybrid Control Of Seismic Structures With Optimal Placement Of Control Devices, Franklin Y. Cheng, Hongping Jiang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A theoretical study is carried out for optimal controller placement and effectiveness of a hybrid seismic response control system comprising a viscous fluid damper and a servovalve-controlled hydraulic actuator. A stochastic seismic response of controlled structures is first investigated with nonorthogonal damping and stiffness; then a statistical method for optimal placement of control devices on seismic-resistant structures is developed. With such placement, a hybrid system can achieve greater performance in that much less control force is required to reduce structural seismic response to a given level. This study also shows the hybrid system is superior to both active and passive …

Visual Form Of Alzheimer's Disease And Its Response To Anticholinesterase Therapy, Stacey Warren, Daniel B. Hier, Dan Pavel

Chemistry Faculty Research & Creative Works

In a 60-Year-Old Woman with the Visual Variant of Alzheimer's Disease, Single Photon Emission Computed Tomography Abnormalities Were Most Marked in the Parieto-Occipital Regions of the Brain. after Treatment with Donepezil, Improvement is Noted on Neuropsychological Testing and on Brain SPECT, Including Increased Perfusion (Metabolism) in the Occipital Lobes.

Recent Research And Developments In Cold-Formed Steel Framing, Roger A. Laboube, Wei Wen Yu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Recent research studies at the University of Missouri-Rolla (UMR) have focused on developing a better understanding of the behavior of cold-formed steel members and truss assemblies. This research was initiated by the more widespread use of cold-formed steel in the residential construction market, and the need to provide structurally reliable, as well as highly economical design solutions. Steel trusses are commonly assembled using C-shaped sections and self-drilling screws. Based on UMR findings, appropriate design recommendations have been proposed for the web and chord members of a truss. Also of concern is the introduction of large holes in the webs of …

Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord L. Gale, Jerry L. Pitt

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The toxicity of common compounds of lead, cadmium and zinc was evaluated in waters similar to that found in the world's largest lead producing area in Missouri. Static, acute toxicity tests were performed using fathead minnows (Pimephales promelas) and water fleas (Daphnia magna) respectively. Test organisms were subjected to varying amounts of sulfide, carbonate, chloride and sulfate salts of lead, zinc and cadmium mixed in hard, alkaline waters typical to this region. Median lethal concentrations were calculated using nominal versus measured metal concentrations. Measured metal concentrations included four different metal fractionation (extraction/filtration) techniques at different pH levels which included "dissolved", …

Improving The Jar Slake, Slake Index, And Slake Durability Tests For Shales, Paul M. Santi

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This study proposes modifications to three shale durability tests to improve reproducibility, reduce the level of effort required, and better correlate the test to actual slaking characteristics. Modifications to the jar slake test reduced test variability by one-third, offering a substantial improvement in consistency, with only a slight loss in the ability of the test to predict slake durability. Analysis showed that slake index test error could be reduced or at least pinpointed by testing groups of samples, rather than single samples. Furthermore, the wet-sieving procedure should be more carefully defined. Analysis of correlations between single- and multiple-cycle slake durability …

Perceptions Of Writing In A Community College Composition Course, Rebecca Ann Kamm

Dissertations and Theses @ UNI

The purpose of this study was to investigate community college students' and their teacher's perceptions about writing in a beginning composition course. This study explored student and teacher views about composition, possible tensions about ways writing is defined, and ways to resolve tension. Specifically, this study addressed the following questions:

1. How do my perceptions as a writing instructor in a beginning community college composition course compare with my students' perceptions?
2. How do my students and I understand real and perceived consequences that arise from various views about writing?
3. How could my students and I mediate or resolve various views about …

A Case Study Of One Iowa Public School Superintendent's Evaluation Process, Gail Vanous Moon

Dissertations and Theses @ UNI

The purpose of this exploratory case study was to identify and describe one Iowa public school district's superintendent performance evaluation process. This study explored the perceptions of one superintendent and one school board of directors in regard to the purposes, criteria, sources of information, and general effectiveness of their superintendent performance evaluation process.

The study was conducted in an urban K-12 public school district in northeastern Iowa. Factors considered in the selection of the school district included: size, location, demographics, as well as the willingness of the participants ta have their voices heard through the researcher. Also, the district was …

Making Meaning From International Educational Experiences: Transforming Inner Landscapes, Sami Lyn Story

Dissertations and Theses @ UNI

This qualitative study sought to gain a more complete understanding of the transformative potential of international educational experiences for US college students. The stories of seven traditionally aged students were evaluated to discern possible commonalties across the diverse experiences. These themes were framed as a cyclical process of departures, passages, and arrivals with special attention given to how students constructed meaning from their intercultural encounters. Factors such as the need to understand, affiliate, and create experiences appeared to be influential along with expectations of host cultures, definitions of family, and time spent in dialectical thought. Students who spent more time …