Digital Commons Network^™

Web Crippling Of High Strength Cold-Formed Steel Beams, Chiravut Santaputra

Doctoral Dissertations

"The structural behavior of high strength cold-formed steel beams subjected primarily to web crippling was investigated analytically and experimentally. In this study hat sections and I-beams, formed from five different types of high strength sheet steels commonly used in the automobile industry, were investigated under various loading conditions. The yield strengths of these sheet steels vary from 58 to 165 ksi.

In addition to the test data gathered in this phase of study, the experimental results obtained from the beam tests conducted at Inland Steel Company and Ford Motor Company were carefully evaluated. The evaluation indicated that the present available …

The Modeling And Analysis Of Multi-Component, Multivalent Biospecific Adsorption, Bo Henrik Arve

Doctoral Dissertations

"A general model is presented and used to predict the dynamic behavior of the adsorption, wash, and elution stages of biospecific adsorption (affinity chromatography) in finite bath and column operations. The model accounts for film and pore diffusional mass transfer resistances and the rates of interaction between adsorbates and ligands. For column operations the effect of axial dispersion in the flowing fluid stream is included. The model is applicable to single and multi-component biospecific as well as non-specific adsorption, and the adsorbates may be monovalent or multivalent. In the elution stage both non-selective and selective elution of monovalent adsorbates is …

Hydrodynamic Characteristics And Coal Combustion Modeling Of A High Velocity Fluidized Bed (Solids Friction Factor, Two Phase Flow, Pressure Profile, Fast), Ronald Wayne Breault

Doctoral Dissertations

A Loop Fluidized Bed (LFB) based on the fast fluidization concept is a novel method for effective solid-gas contact and can play an important role in coal combustion. It can be operated under pressure making it eminently suited for the production of high temperature gas from coal for operating gas turbines for power generation. The LFB can operate over a wide range of gas flow rates and coal can be introduced at various points without excessive pressure drops. Further, it is possible to capture higher amounts of sulfur dioxide due to the use of fine dolomite or limestone particles. This …

Risk And Uncertainty (Utility, Decision), Paul Snow

Doctoral Dissertations

The conventional theory of decision making under risk relies on axioms that reflect assumptions about people's subjective attitudes towards wealth. The assumptions are unverifiable, and the axioms are too restrictive. They forbid some decision rules that a plausibly rational decision maker ("DM") could find useful.

A new method, at once less restrictive and less dependent upon subjective assumptions, motivates expected utility techniques by assuming that a DM wishes to place an upper limit on the probability of ruin. All bounded-above, increasing functions defined over a suitable domain can serve as utility functions.

Now, DM can evaluate lotteries according to their …

Effects Of Field-Dependence/Independence And Sex On Patterns Of Achievement And Grading In A First-Semester Calculus Course (Cognitive Style, Remedial Mathematics, Grading Bias, Appraisal, College), Timothy John Kelly

Doctoral Dissertations

The purpose of this study was twofold: first, to investigate effects of field-dependence/independence (f-d/i), sex, and different types of audiovisual remedial instruction on mathematics achievement (Experiment I); second to investigate the effects of student and grader cognitive style (f-d/i) and sex on calculus test grades (Experiment II).

One hundred fifty first-semester calculus students, identified by an algebra/trigonometry pretest as requiring trigonometry remediation, served as subjects for Experiment I. As measures of f-d/i, the Group Embedded Figures Test (GEFT) and The Miniaturized Rod and Frame Test (MRFT) were administered to the subjects, who were apportioned into six experimental groups, representing three …

An Analysis Of Mill Sound Levels To Aid In The Control And Understanding Of The Grinding Process, Scott Douglas Morrison

Doctoral Dissertations

“An experimental study has been made to evaluate the relationships between grinding parameters and the directional sound levels emitted from the collision of the grinding media with the mill wall for a laboratory batch ball mill.

Discrete frequency and single frequency band sound pressure level measurements were performed to investigate the changes in sound levels with grind time. It was demonstrated that the reduction in sound levels with grind time observed for a narrow sized feed can be used to indicate optimum breakage rates, overall time-based particle size distribution, and ore character.

The relationships established with the discrete frequency and …

Corrosion In Magnesium And A Magnesium Alloy (Az91c) As Modified By Ion Implantation, Sanay Akavipat

Doctoral Dissertations

"Magnesium and a magnesium alloy (AZ9 1C) have been ion implanted over a range of ion s energies (50 to 150 keV) and doses (1 x 10¹⁶ to 2 x 10¹⁷ ions/cm²) to modify the corrosion properties of the metals. The corrosion tests were done by anodic polarization in chloride -free and chloride containing aqueous solutions of a borated-boric acid with a pH of 9.3. Anodic polarization measurements showed that some implantations could greatly reduce the corrosion current densities at all impressed voltages and also increased slightly the pitting potential, which indicated the onset of the …

Dissolution Of Multi-Component Systems, Robin Ashley Murphy

Doctoral Dissertations

"The validity of ideal barrier layer diffusion kinetics was examined in the NaCl/KCl - glycerol and Al₂O₃-CaO-Al₂O₃-SiO₂/slag corrosion systems. Single crystals and dense polycrystalline plates of pure NaCl or KCl exhibit steady-state corrosion rates within 10%, of calculated theoretical values, while dense mixtures of the two salts corrode at rates higher than either pure material. The results are compared to the grooving phenomena of NaCl/KCl bicrystals.

Polycrystalline Al₂O₃ is shown to corrode at the same rate as single crystal sapphire at 1400°C in CaO-SiO₂-Al_{2 …}

Numerical Simulation Of Mixing Processes In Two-Dimensional Channel Flows, Milan Karel Straka

Doctoral Dissertations

"Recently, considerable interest has arisen in the numerical simulation of laminar and turbulent transport phenomena. More knowledge in this field is needed to improve predictions of heat and mass transfer processes in a variety of technical fields.

In this work a new computationally efficient transport model is developed. It consists of partially parabolized time-dependent equations of motion, continuity, and concentration of nonconservative species. Pertinent equations are solved numerically for both laminar and turbulent flow.

Results of calculations of laminar flow in the entry region of a parallel-plate channel agree well with the work of other authors. For turbulent flows, the …

Measurement Of The Far Infrared Optical Properties Of Steel, Aluminum, Evaporated Iron, And Teflon Fep, Raymond E. Paul

Doctoral Dissertations

"The optical properties of low-carbon shim steel, aluminum foil, and Teflon FEP have been measured in the 20 cm^-1 to 70 cm^-1 range. In particular, measurements of surface impedance for aluminum and low-carbon steel were used to calculate the imaginary part of the dielectric constant (&_{m, 2}). The resulting values of &_{m, 2} were of order 10⁶ for aluminum, and 10⁵ for steel. The imaginary part of the dielectric constant for metals is several times greater in magnitude than the real part in the frequency range of this experiment. Calculations of &_{m, …}

Optical Properties Of Natural Minerals In The Far-Infrared, Larry Lavern Long

Doctoral Dissertations

"The reflectivity of natural mineral powders were measured in the far infrared. The complex indices of refraction were then determined by Kramers-Kronig analysis or dispersive analysis. The samples were constructed by pressing the powdered sample into a 13 mm diameter pellet. A few of the samples that were measured were kaolin, illite, and montmorillonite, clay samples that could not be obtained in large single crystals. For calcite and gypsum crystals a comparison between the single crystal measurements and powder measurements was done to determine the effect of sample preparation on the measured spectra"-- Abstract, p. ii

A Parallel Branch And Bound Algorithm For Integer Linear Programming Models, Rochelle L. Boehning

Doctoral Dissertations

"A parallel branch and bound algorithm is developed for use with MIMD computers to study the efficiency of parallel processors on general integer linear programming problems. The Haldi and IBM test problems and a System Design model are used in the implementation of the algorithm. Initially the algorithm solves the Haldi and IBM test problems on a single processor computer which simulates a multiple processor computer. The algorithm is then implemented on the Denelcor HEP multiprocessor using two of the IBM problems to compare the results of the simulation to the results using an MIMD computer. Finally the algorithm is …

Kinetics And Reactor Design In The Pyrolysis Of Tar Sands, Charles Arthur Lechner

Doctoral Dissertations

"Data from the thermal decomposition of bitumen from Utah tar sands was obtained and analysed with both isothermal and non-isothermal chemical reaction models. The use of a power rate law to describe the complex kinetics of pyrolysis gave agreement with the experimental data that was approximate, but adequate for design purposes. The results indicated a reaction rate that was second order in bitumen content, with an activation energy of about 17 to 20 kcal/gmol.

Data for the boiling point distribution of the products was consistent with a change of mechanism from vaporization to pyrolysis as the samples are heated. Higher …

Electrochemical Evaluation Of Zinc Electrolyte, Rajesh Kumar Singh

Doctoral Dissertations

"The polarization characteristics of acidified zinc sulfate electrolyte with varying solution chemistries were examined by cyclic voltammetry. An attempt was made to correlate the polarization results with the morphological and current efficiency data in order to develop a better understanding of the more fundamental aspects of impurity and additive behavior during the zinc electrodeposition process.

A statistical screening design program was conducted to determine the effects of certain operating parameters on the nucleation potential of zinc from sulfate electrolyte. The variables studied included: solution temperature, H₂SO₄ and Zn concentration, and scan rate. The solution temperature was found to be the …

Predicting Potential Ascospore Dose Of Venturia Inaequalis (Cke) Wint In Commercial Apple Orchards Of New Hampshire (Modeling, Epidemiology, Disease Management), David Mark Gadoury

Doctoral Dissertations

A theoretical model (Prot. Ecol. 5:103-125) was the framework of a study of factors affecting the number of Venturia inaequalis ascospores per m('2) orchard floor per season (PAD) in New Hampshire apple orchards. PAD was calculated as the product of scab lesions per m('2) leaf tissue at leaf fall, pseudothecia per lesion, asci per pseudothecium, the proportion of the orchard floor covered by leaf litter at bud break, and ascospores per ascus. Disease incidence and the proportion of lesions that formed mature ascocarps were strongly correlated; lesion fertility was directly proportional to disease incidence at leaf fall. Most lesions from …

Covariance Structural Models For Mathematics Achievement And Participation: An Investigation Of Sex Differences At The Level Of College Calculus Using Factorial Modeling, Thomas Patrick Dick

Doctoral Dissertations

The purpose of this study was to develop covariance structural models that would explain, in terms of orthogonal latent variables, the correlations observed among mathematics achievement and participation measures and related cognitive and affective variables. A random sample of college calculus students (N = 268; 124 females and 144 males) was administered: (1) a battery of cognitive tests, including measures of spatial-visual ability, field independence/field dependence, and logical reasoning; and (2) a battery of affective scales, including measures of attitude toward mathematics, confidence, perceived usefulness of mathematics, effectance motivation, and locus of control. Measures of previous academic achievement and participation …

Some Problems In Bayesian Inference In A Nonclassical Setting (Operational Statistics, Betting Rates, Coherence), Carolyn Margaret Magness

Doctoral Dissertations

The Bayesian inference strategy is studied within the framework of operational statistics (generalized sample spaces). Conditions necessary and sufficient for consistency and strict consistency of a complete betting rate assignment are derived. A constructive proof is given of the existence of a unique second-order probability which induces a given consistent and countably additive complete betting rate assignment. Continuity of the Bayesian inference strategy is investigated. Asymptotic properties of the Bayesian inference strategy are examined both at the level of betting rates and at the level of second-order probabilities.

Statistical Methods For Analysis Of Cancer Chemoprevention Experiments, Stephen Michael Kokoska

Doctoral Dissertations

The experimental systems studied in this dissertation are designed to investigate the effect of diet on incidence rates of cancer. These investigations involve the chemical induction of tumors in experimental animals in order to test the chemopreventative effects of various substances. Both tumor number and rate of tumor development are important in evaluating the effects of a chemopreventative agent. This is made difficult, when multiple tumors occur, by the confounding of the number of induced tumors and their time of detection. This confounding occurs because experiments are terminated before all induced tumors have been detected. Fewer tumors observed in one …

Estimation Of United States Import Demand And Export Supply In A Multi-Input Multi-Output Model, Using Human Capital And R & D As Factors Of Production (Research, Development), Evangelos Nikolaou Charos

Doctoral Dissertations

Traditionally the estimation of the import and export functions has been done by specifying either linear or loglinear functions of some income and relative price variables then using, usually, ordinary least squares technique. This procedure is subject to a wide range of criticisms due to its lack of theoretical foundation and because of its implicit assumptions. In this thesis import and export functions will be derived within a more general theoretical framework first introduced by Samuelson and investigated empirically by Foley and Sidrauski in their treatment of the production side of the economy. This more general framework was also used …

Unsteady-State Cylindrical, Spherical And Linear Flow In Porous Media, Allan Jeffrey Anthony Joseph

Doctoral Dissertations

"The general problem of unsteady flow phenomena in porous media as considered in this investigation. Emphasis was placed upon the short-term flow characteristics within cylindrical, spherical and linear reservoir geometries, and practical analysis methods were developed for each problem. Additionally, nonlinear unsteady flow behavior in infinite reservoirs was considered. Each solution obtained could optionally be implemented by hand or computer, and several FORTRAN subprograms were also presented.

At present, the only way to analyze pressure transient data prior to the development of the "semi log straight line" is by type curve matching techniques. However, this study indicated that a reliable …

Using Prisms To Excite Leaky Waves Or To Launch Surface Electromagnetic Waves, Gerald Kent Sirotiak

Doctoral Dissertations

"The ability of prisms to couple incident VEM radiation from a laser beam into leaky waves or to launch surface electromagnetic waves has been investigated. We have set out to discover wheth~r or not a single prism placed above an air-metal interface can be used to couple light from a laser beam into leaky electromagnetic waves. We have then attempted to relate the single prism technique to tb.e double prism technique for launching surface waves. We have also compared the coupling into a single interface to that into a waveguide.

We have found that prisms are unable to couple incident …

The Modeling And Control Of Freeze Dryers, Martin James Millman

Doctoral Dissertations

"Two models of the freeze drying process were constructed and used to study various operational policies in order to determine the policy that would provide the shortest drying times.

The sublimation model which accounts only for the removal of frozen water, is found to predict shorter times for the free water removal phase than the sorption-sublimation model which properly accounts for the removal of frozen and bound water.

This study shows that the policy which produces the shortest free water removal phase, also produces the shortest overall drying time. This policy, predicted by both models, holds the chamber pressure at …

Angular Differential Cross Sections For The Excitation Of 1¹S Helium To The 2¹S And 2¹P States By 25- To 100-Kev Proton Impact, Thomas Jay Kvale

Doctoral Dissertations

"Angular differential cross sections for the proton impact excitation of ground state helium (1¹S) to the 2¹S and 2¹P states have been measured for the first time in the energy range 25- to 100-keV using the energy-loss technique. The present data have been numerically summed over the 2¹Sand 2¹P states to produce differential cross sections for excitation to the composite n=2 state and are in excellent agreement with previous experimental measurements of that process. Total cross sections have been obtained by numerically integrating the present data over scattering angle. and …

Fixed Bed Sorption With Recycle, John Thomas Casey

Doctoral Dissertations

"A mathematical model that describes single and multicomponent recycle-sorption systems is constructed. The model accounts for the generation of species by chemical reactions occurring in a single perfectly mixed tank, in the bulk fluid of the sorbent bed, and in the pores of the adsorbent particles.

Results are shown for single zeroth, first and second order reversible reactions as well as a network consisting of two first or second order reactions which may occur in series or parallel. For systems in which a single reaction occurs, both linear and non-linear equilibrium adsorption isotherms are considered. If multiple reactions occur, then …

The Theoretical Genesis Of Capital Using A Commodity Theory Of Value, Spencer Jay Pack

Doctoral Dissertations

The purpose of this dissertation is to show that the basic framework of Marx's analysis of capitalism is sufficiently independent of the labor theory of value to survive the replacement of the labor theory of value with a Sraffian-based commodity theory of value. It addresses a problem posed by such economists as Joan Robinson and Ian Steedman. They criticize the labor theory value from a Sraffian perspective. They argue that economists should use a basically Marxian framework when analyzing capitalism, but not use the labor theory of value. The question then arises as to what remains of Marx's work when …

Effects Of Rotary Inertia And Shear Deformation On Extensional Vibrations Of Continuous Circular Curved Beams, Mohamed El-Said Said Issa

Doctoral Dissertations

This dissertation is devoted to the dynamic analysis of continuous circular curved beams. The dynamic stiffness matrix is derived for the determination of natural frequencies of continuous curved beams undergoing in-plane vibrations. The formulation of stiffness matrix may be widely applied to problems with various consideration of Bernoulli-Euler Theory, Rayleigh Theory and Timoshenko Theory. Using this formulation for dynamic loading, the fixed-end moment, shear and thrusts for concentrated and distributed loads have been derived. Two continuous circular curved beams subjected to free and forced vibrations are given to illustrate the application of the proposed method and to show the effects …

Digital Analysis Of Pulse Code Modulated Signals In Telecommunications Channels, Edmund Littlefield Chase

Doctoral Dissertations

In this dissertation the techniques required to test pulse code modulated telecommunications channels are developed using the fast Fourier transform. The techniques are then applied through the design and assembly of the corresponding hardware. Windowing of data to improve spectral estimation is discussed as well as the conditions where special test signals may be synthesized to preclude the need for windowing. Conjugate-periodic functions encountered in prime radix transforms are defined and their fast transform techniques are developed.

Comedy: The Uncertain Terrain Of John Hawkes, Peter M. Johnson

Doctoral Dissertations

This dissertation examines the nature and function of John Hawkes' comic method. Although most critics acknowledge that Hawkes writes comedy, very few of them agree on the moral nature of this comedy. Chapter I examines these differing responses to Hawkes' work and offers an alternative way of evaluating his humor, based on his own and other critics' comments on comedy. This chapter also suggests that our responses to Hawkes' humor occur on an uncertain terrain where two or more, sometimes opposite, reactions to a text clash, forcing us into continuous moments of indecision.

Chapter II deals with Hawkes' first novel, …

Homogeneous Nucleation Of Nonane In Argon Using An Expansion Cloud Chamber, Gregg Wesley Adams

Doctoral Dissertations

"The homogeneous nucleation rate of nonane has been measured using an expansion cloud chamber. Data were obtained for pre-expansion temperatures of 45°C, 35°C, 25°C, 15°C, 5°C, and -5°C. The measured nucleation rate ranges from 10² to 10⁵ drops/cm³ -sec over a temperature range of 216 K to 270 K. The data set is sufficiently extensive to provide a detailed test for nucleation theories applied to nonane. The measured rates are compared with the "classical" nucleation theory and with a modified classical theory using the replacement factor of Reiss, Katz and Cohen (RKC). It is found that neither …

Theoretical Studies Of Water On Substrates, Sergio M. Terrazas

Doctoral Dissertations

"Model interaction potentials for H₂O on a basal f)-silver iodide substrate containing two types of defects, a potassium impurity and a four atomic layer ledge, are used to calculate optimal binding energy contours for the adsorbed H₂O molecule. (J. Phys. Chern. 84, 1473(1980)). The model substrate with the potassium impurity appears to increase the optimal binding energy at the preferred adsorption sites to 23 kcal/rnol -- a value approximately 40 % larger than the maximal binding energy sites on the defect-free model silver-exposed basal plane of AgI. The impurity also distorts the hexagonal symmetry of the …