Digital Commons Network^™

Cw Laser Oscillations And Tuning Characteristics Of Neodymium-Doped Lithium Niobate Crystals, Laird D. Schearer, Michèle Leduc, J. Zachorowski

Physics Faculty Research & Creative Works

We have obtained over 250 mW of CW laser emission at 1084 nm from a neodymium-doped single crystal of lithium niobate when the rod was end pumped by 1 W from a Kr⁺ laser at 752 nm, Thresholds of less than 30 mW are obtained with a weak output coupler, rising to 220 mW with a 25 percent transmitting output mirror. The laser could be tuned over 3 nm around the peak at 1084.4 nm with a thirl, uncoated etalon in the cavity. Copyright © 1987 by The Institute of Electrical and Electronics Engineers, Inc.

Structural Behavior Of Members Consisting Of Flat And Curved Elements, M. Brad Parks

Doctoral Dissertations

"Local buckling of stiffened and unstiffened curved elements has been investigated both experimentally and analytically. Stiffened curved elements are supported on all four edges while unstiffened curved elements are supported along three edges with one longitudinal edge free.

A series of stub column, beam, and shear tests have been performed for sections containing curved elements. The tested specimens were formed from sheet steels with yield strengths ranging from 27 to 88 ksi. The radius-to-thickness, R/t, values of the curved elements varied from 12 to 438 whereas the arc length-to-thickness, bit, ratios ranged from 23 to 218.

As a result of …

Intensional Reasoning About Knowledge, Oliver B. Popov

Doctoral Dissertations

"As demands and ambitions increase in Artificial Intelligence, the need for formal systems that facilitate a study and a simulation of a machine cognition has become an inevitability. This paper explores and developes the foundations of a formal system for propositional reasoning about knowledge. The semantics of every meaningful expression in the system is fully determined by its intension, the set of complexes in which the expression is confirmed. The knowledge system is based on three zeroth-order theories of epistemic reasoning for consciousness, knowledge and entailed knowledge. The results presented in the paper determine the soundness and the completeness of …

A Mössbauer Effect Study Of The Structural And Magnetic Properties Of Y₂(Fe₁₋ₓalₓ)₁₄B, Ying-Chang Yang, Dwayne E. Tharp, Gary J. Long, Oran Allan Pringle, William Joseph James

Chemistry Faculty Research & Creative Works

The crystallographic and magnetic properties of Y₂(Fe₁₋ₓAlₓ)₁₄B, where x equals 0.00, 0.02, 0.04, 0.06, and 0.08, have been investigated by Mössbauer spectroscopy and magnetic measurements at room temperature and 85 K. Magnetic anisotropy and magnetization changes with aluminum substitution indicate that, because of size, the aluminum preferentially occupies the j₂ site over the remaining five crystallographically nonequivalent iron sites. This preferential occupation has been confirmed by Mössbauer spectral studies, which indicate that the compositional variation of the hyperfine field for each site is related to the number of near-neighbor aluminum atoms for the site. This compositional variation is helpful in …

Modeling And Analysis Of Biospecific Adsorption In A Finite Bath, B. H. Arve, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A general model is presented and used to predict the dynamic behavior of the adsorption and wash stages of bio specific adsorption (affinity chromatography) in a finite bath. The model accounts for film and diffusional mass transfer resistances as well as for the rates of interaction between adsorbates and ligands. The model is applicable to single and multicomponent bio specific as well as nonspecific adsorption, and the adsorbates may be monovalent or multivalent. The predictions of the model are compared with the experimental data of the adsorption of β‐galactosidase onto immobilized anti‐β‐galactosidase. The results of bio specific adsorption of bivalent …

Development Of Design Criteria For Ferritic Stainless Steel Cold-Formed Structural Members And Connections, Pieter Van Der Merwe

Doctoral Dissertations

"This dissertation describes the development of the basic criteria needed for the design of structural members cold-formed from certain ferritic stainless steels. The Allowable Stress Design method as well as the Load and Resistance Factor Design method receive attention. The ferritic stainless steels under consideration are: Types AISI 409 and 430 as well as a modified Type 409 steel, designated 3CR12 steel, developed and produced by the speciality steel producing company, Middelburg Steel and Alloys in South Africa.

The mechanical properties needed for structural design are established. It is shown through an experimental study that the design provisions for the …

A.R.M.S., Arbitrary Robot Modeling System, William Richard Gerlt

Masters Theses

“This paper deals with the mathematical modeling of robot arms. Modeling robot arms includes finding a suitable way to describe a robot, turning the description into a mathematical system, and using the system to find a set of equations which can be used to control the robot.

One of the problems associated with robot modeling is that it involves a great deal of mathematics. When the process is done by hand, the large volume of mathematics makes the process very time consuming and prone to errors. These problems are part of the motivation for automating the modeling of robots.

ARMS …

A Petrographic Investigation Of The Rhythmically Bedded Upper Fayetteville Formation (Mississippian) In Northern Arkansas, Edith Ann Starbuck

Masters Theses

"The upper Mississippian Fayetteville Formation in northern Arkansas is primarily a calcareous black shale, but in some localities the upper one third to one half of the formation is made up of alternating black shales and limestones. Comparable lithologies have been suggested by some (Hallam, Ricken, Kent, and Sujkowski) to have been created by the diagenetic segregation of carbonate from calcareous shale.

Petrographic thin section analysis reveals that the lowest limestone beds of the rhythmic upper Fayetteville are made up almost entirely of microspar and all fossil material is recrystallized, even to the point of obliteration in some cases. The …

The Force On A Lattice Defect In An Elastic Body, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

It is shown that the force on a lattice defect in an elastic body is, like the force on a disclination in a nematic liquid crystal, a real force which, for equilibrium, must be balanced by an external force applied to the closed surface enclosing the defect. © 1987 Martinus Nijhoff Publishers.

Effect Of Material Parameters On The Initiation And Growth Of Adiabatic Shear Bands, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The thermomechanical problem involving simple shearing of a finite slab made of an isotropic and viscoplastic material is studied with the objective of finding the effect of the strain hardening parameter, strain-rate hardening parameters, thermal softening coefficient and thermal conductivity on the initiation and growth of adiabatic shear bands. The body is placed in a hard loading device, i.e., the velocity is prescribed at its top and bottom surfaces. A shear band is presumed to have formed if the addition of a perturbation in the temperature at the onset of plastic flow results in a localization of the shear strain. …

Calculation Of Mass Transfer Coefficients In Metal Deposition Using Electrochemical Tracer Techniques, Thomas J. O'Keefe, J. S. Cuzmar, S. F. Chen

Materials Science and Engineering Faculty Research & Creative Works

A modification of the tracer technique of Ettel has been developed for determining mass-transfer coefficients in electrolytes for both electrowinning and electrorefining systems. The method involves the direct measurement of the limiting current density of a more noble tracer ion at low concentration by cyclic voltammetry techniques in an electrolyte of choice. A Ag+tracer in acid copper sulfate is used as the example. Additional tests were made by code positing the tracer with copper to compare the results of the two methods. The effect of copper ion concentration and temperature on the electrochemical and transport properties of the solution were …

Contribution Of Transfer Ionization To Total Electron Capture From A Helium Target, J. A. Tanis, M. W. Clark, R. Price, Ronald E. Olson

Physics Faculty Research & Creative Works

The contribution of transfer ionization (TI) to total electron capture has been measured for O^q+ ions (q=5, 6, 7, and 8) colliding with helium at energies from 0.5 to 1.5 MeV/u. These measurements, along with other published results, suggest a maximum TI contribution to total capture of 0.15q0.5 at E (in keV /u)q0.5100 The results demonstrate that the failure to account for transfer ionization in total single-charge-transfer cross sections may lead to large discrepancies between experiment and theory. © 1987 The American Physical Society.

Oxidation Kinetics Of Polycrystalline Lacro3, Chikung J. Yu, Don M. Sparlin, Harlan U. Anderson

Physics Faculty Research & Creative Works

The oxidation kinetics of polycrystalline LaCrO3 were determined by measuring the time and temperature dependence of the weight and conductivity change of reduced samples. A region of fast diffusion followed by a smaller, slower diffusion "tail" was observed in the thermogravimetric measurements. This observation can be interpreted as the rapid diffusion along the grain boundaries and subsequent diffusion into the body of the grain. The absence of the "tail" in the conductivity measurements is due to the high hole mobility along the boundaries. Copyright © 1987, Wiley Blackwell. All rights reserved.

Ionization And Charge Exchange In Multiply-Charged-Ion-Helium Collisions At Intermediate Energies, M. L. Mckenzie, Ronald E. Olson

Physics Faculty Research & Creative Works

A Bohr classical model for He is applied to multiply charged ions colliding with He at intermediate energies. Reactions studied are single-electron capture, single and double ionization, and electron-capture ionization for projectile charge states q=1+ to 100+, and the energy range E=1-5 MeV/amu. The dominant electron-removal collision process is single ionization. For the higher-charge-state ions, single-charge exchange is found to be primarily due to transfer ionization, a two-electron process where one electron is ionized and the other is captured by the projectile. For low-charge states, the single- and double-ionization cross sections are close to the expected q² and q …

Computer-Aided Testing Of Electrical Machines: Software Development, Max Darwin Anderson, Steven A. Hauk, Robert Laramore, Hardy J. Pottinger

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Computer-Aided Testing Of Electrical Machines: Software Development, Max Darwin Anderson, Steven A. Hauk, Robert Laramore, Hardy J. Pottinger

Electrical and Computer Engineering Faculty Research & Creative Works

Computer-aided test stations have been developed for research, experimentation, and testing of electric motors and generators. Data acquisition and control of the machines and drives are provided through a computer and its interfaces. Machines are connected to the computer through transducers for data acquisition, and power electronic drives for machine control. General software was written to enable the monitoring of all transducers continuously on the CRT screen while giving the user manual control of the machines and drives. Specialized software was written for automatic control of the induction, dc, and synchronous machines for specific experiments on each type of machine. …

Current That Kills., Burns E. Hegler

Electrical and Computer Engineering Faculty Research & Creative Works

The authors point out the hazards associated with electricity. Several methods for preventing or coping with inadvertent shocks are described.

Naming Of Rolla, Missouri, Gerald Leonard Cohen

Arts, Languages and Philosophy Faculty Research & Creative Works

No abstract provided.

Характеристика Лексико-Семантической Группы Слов, Обозначающих Звуки, В Русском Языке, В Сопоставлении С Французским Языком - 1987, Irina V. Ivliyeva

Arts, Languages and Philosophy Faculty Research & Creative Works

No abstract provided.

Interaction Of Calcium With Hema/Maa Copolymers., Michael R. Van De Mark, N. D. Lian, M. Brandon, E. C. Eckstein

Chemistry Faculty Research & Creative Works

Polymeric materials based upon 2-hydroxyethyl methacrylate (HEMA) have been extensively used, especially in biomedical applications. Several reports have appeared in the literature during the past 20 years regarding the behavior of these materials upon exposure to body fluids. The results of these studies have ranged from good biocompatibility to calcification. The presence of methacrylic acid (MAA), in HEMA-based copolymers gives rise to a swelling transition at pH 7. The present study relates the swollen volume of HEMA/MAA gels to the concentrations of calcium salts at a pH where the MAA is ionized, as would occur for implanted gels. This swollen …

Lamellar Liquid Crystal And Other Phases In The System Sodium Dodecyl Sulfate, Hexylamine, Water, And Heptane, Jiafu Fang, Raymond L. Venable

Chemistry Faculty Research & Creative Works

Phase equilibria have been studied for the system composed of sodium dodecyl sulfate, hexylamine, heptane, and water. Greatest emphasis has been placed on the lamellar liquid crystal region and X-ray diffraction measurements. Equations are developed or modified to allow determination of the degree of penetration of water into the amphiphilic double layer as a function of water or amphiphile concentration. It is found that the interfacial area occupied by the polar or ionic head groups of amphiphiles increases with increasing water content. © 1987 Academic Press, Inc. All rights reserved.

Fourier Transform Nmr Self-Diffusion Studies Of A Nonaqueous Microemulsion System, K. P. Das, A. Ceglie, B. Lindman, Stig Friberg

Chemistry Faculty Research & Creative Works

Self-diffusion coefficients of the components of the microemulsion system glycerol/hexanol/sodium dodecyl sulfate (SDS) were determined in the presence and absence of an oil, p-xylene, and the results were compared with those from corresponding aqueous systems (i.e., glycerol replaced by water). In the aqueous system, the water in the hexanol rich isotropic liquid showed a diffusion coefficient less than 10% of that of free water, while that of hexanol was roughly 80% of that of free hexanol; such restricted motion of the water is consistent with the presence of water as discrete droplets. Partial substitution of p-xylene for hexanol did not …

Conductivity Study Of The Microemulsion System Sodium Dodecyl Sulfate-Hexylamine-Heptane-Water, Jiafu Fang, Raymond L. Venable

Chemistry Faculty Research & Creative Works

Conductivity measurements on this system are interpreted in terms of the percolation and effective medium theories. From this interpretation, the ratio of hexylamine to sodium dodecyl sulfate in the microemulsion droplet surfaces can be deduced. Following that determination, it is possible to obtain approximate values for the radius of the water pools and the number and surface area of droplets per unit volume of the microemulsion system. © 1987.

Surfactants And The Stratum Corneum Lipids, Stig E. Friberg, Lisa Goldsmith, Hamdan Suhaimi, Linda D. Rhein

Chemistry Faculty Research & Creative Works

A simplified mixture of model stratum corneum lipids was mixed with different surfactants to make a preliminary estimation of the influence of surfactants on the stratum corneum lipid structure. The results revealed differences between cationic and anionic surfactants and between anionic surfactants with different structures. © 1998.

Critical Phenomena In Nonaqueous Microemulsions, Stig Friberg, Yuh Chirn Liang

Chemistry Faculty Research & Creative Works

The pseudo ternary phase diagrams of the four-component system glycerol, sodium dodecyl sulfate, hexanol and decane with the weight ratio of hexanol to decane equal to 100/0, 90/10, 75/25, 50/50, and 25/75 were determined at 30°C. The systems gave only isotropic solutions and no liquid crystalline phases. The nonaqueous regions corresponding to the W/O microemulsion region in aqueous systems suggested critical behavior as demonstrated by the convergence of tie lines and by light scattering intensity which gave a pronounced maximum at the point of converging tie lines. This maximum was transferred to higher glycerol/hexanol ratios with added surfactant and to …

Estimation Approach To Locating Buried Geological Interfaces, A. Omar, A. Addeeb, C. Slivinsky, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The objective of the estimation work described in this paper is to improve algorithms for reconstructing the geometric configuration of acoustic reflecting surfaces. The conventional migration method of locating these surfaces is reviewed. A recent imaging condition which is closely related to the boundary condition at the geological interface is then described. This later procedure results in two outputs. One can be used to reconstruct the shape of the unknown acoustic reflector, while the second output estimates the acoustic wavespeed on the transmission side of the boundary. When noise is present in the reflected signal, the performance of the method …

Soil-Shrinkage Induced Structural Failure, David Newton Richardson, Richard Wesley Stephenson, Daniel Molloy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Paper Describes an Investigation into the Causes of Structural Damage to a Retirement Home and the Subsequent Rehabilitation Project. the Investigation Revealed that the Damage Was Caused by Shrinkage of the Soils Beneath the Structure's Foundation as a Result of Dry Weather, Shrinkage-Prone Characteristics of the soils, Deviation from the Original Design, and Poor Construction Techniques. the Structure Was Subsequently Underpinned to Rock using the Inclined Drilled Pier Method. Interaction between Design and Construction Professionals is Also Presented. © ASCE.

Interobserver Reliability In The Interpretation Of Computed Tomographic Scans Of Stroke Patients, David Shinar, Cynthia R. Gross, Daniel B. Hier, Louis R. Caplan, Jay P. Mohr, Thomas R. Price, Philip A. Wolf, Carlos S. Kase, Irene G. Fishman, Joshua A. Barwick, Selma C. Kunitz

Chemistry Faculty Research & Creative Works

Interobserver Reliability in Interpretation of Computed Tomographic Images Was Studied by Six Senior Neurologists Who Independently Evaluated on a Standardized Stroke Data Bank Form the Brain Lesions of 17 Patients. the Results Analyzed with K Statistics Yielded Moderate to Substantial Agreement on Most Items of Interest Including the Stroke Pathology and Anatomy. in General, the Levels of Agreement Were as High as Previously Reported for the Diagnosis of the Mechanism of the Stroke, and Much Higher Than on Many Stroke History Items and Items of Neurologic Examination. Excellent Agreement Was Obtained for the Detection of Infarcts and Intracerebral Hemorrhage, and …

Fluidized-Bed Gasifier Engine System Using Rice Hulls, Luis Cruz Baja

Masters Theses

"The operation of a fluidized-bed gasifier using rice hulls and a spark-ignition, internal combustion (IC) engine on product gas at the optimum reactor conditions and on gasoline produced generator loads of 6.7 KWe and 10.5 KWe at average speeds of 1740 RPM and 1785 RPM and thermal efficiencies of 12.7% and 13.8%, respectively. The diesel engine operation on dual diesel fuel oil (DFO) product gas and 100% DFO generated 8.0 KWe and 8.3 KWe at 1416 RPM and 1552 RPM and thermal efficiencies of 10.2% and 20.2% respectively. The gasoline engine could be run on 100% product gas while the …

The Synthesis And Characterization Of Polycarbonates Based On 1,1'-Dihydroxyethyl-2,2'-Biimidazole, Judith J. Garces

Masters Theses

"The synthesis of polycarbonates formed by the reaction of 1,1'-dihydroxyethyl-2,2'-biimidazole and diphenyl or diethyl carbonates was investigated and the products formed were characterized. The molecular weights of the polymers were dependent on catalyst, ratio of starting materials, nature of carbonate (aromatic or aliphatic) and method of polymerization. Isolated polymers exhibit a linear structure. They have no well-defined melting points (melting pt. range of 280- 330⁰C) indicating low degree of crystallization, and undergo less than 9% decomposition below 200⁰C"--Abstract, page ii.