Engineering Commons^™

Evaporite Diapirs In The La Popa Basin, Nuevo Leon, Mexico., Robert C. Laudon

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Reconnaissance mapping and stratigraphic work in the La Popa basin of Neuvo Leon, northern Mexico, have revealed two large structural features with cores of gypsum and anhydrite at the surface. These features are interpreted to be the surface expression of evaporite diapirs. Geostatic loading is considered to be the most important mechanism for emplacement of the domes. -from Author

Dynamics Of Twinning In Natural Α-Quartz, Alexander Aning, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

Finite amplitude internal friction experiments in α-quartz are described and interpreted in terms of the theory of nonlinear anelasticity. The theory predicts a linear relationship between the driving force of the excitation and the period of the auto modulation at its onset. This relation is substantiated by experiments performed with a natural α-quartz reed vibrating in flexure at resonance frequencies between 65 and 170 Hz in the temperature range of 162° and 224°C. The data suggests that Dauphiné twinning in α-quartz causes the auto modulation governed by an activation energy of 92 kJ mole. This activation energy characterizes short distance …

Dynamics Of Stress Induced Hydride Formation In Vanadium, Alex Aning, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Oxygen Activity Dependence Of The Electrical Conductivity Of Li‐Doped Cr2o3, R. F. Huang, A. K. Agarwal, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The electrical conductivity of Li‐doped Cr₂O₃ was investigated as a function of PO₂, temperature, and dopant content. Results show that the electrical conductivity remains almost unchanged with decreasing P O₂ in the high‐P O₂ region but decreases rapidly at low P O₂. A second phase was found in samples which contained more than 0.85 mol% Li. The results are explained by a model in which the concentration of charge carriers is dependent on the acceptor dopant and oxygen vacancy concentration. Copyright © 1984, Wiley Blackwell. All rights reserved

Non-Linear Oscillation, Automodulation And Anelasticity, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

The auto modulation observed in the course of internal friction is discussed as a special example of the universal nature of non-linear oscillations. Universal features of non-linear oscillations are the requirement of energy supply or negative damping and the period doubling route to chaos. The negative damping responsible for the auto modulation is described in terms of the soliton model for twinning deformation. © 1984 The Japan Society of Applied Physics.

Electronic Ballast Having Emitter Coupled Transistors And Bias Circuit Between Secondary Winding And The Emitters, Don Cronin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An electronic ballast for energizing fluorescent lamps comprising a converter including a rectifier and a filter for converting an alternating source voltage into a direct current voltage, a network including first and second switching transistors, a tank circuit having a primary winding of a transformer, a secondary winding of the transformer for providing feedback of a portion of the voltage developed across the tank circuits and a bias circuit coupled between the opposite ends of the secondary winding and the emitters of the transistor for alternatively applying bias to the transistors, the network serving to convert a direct current voltage …

Correction To “Two-Dimensional Markov Representations Of Sampled Images”, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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 …

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 …

Thermogravimetric And Electrical Conductivity Studies Of Mg-Doped Lacro₃ And La-Doped Srtio₃, Brian Keith Flandermeyer

Doctoral Dissertations

"Mg-doped LaCrO₃ and La-doped SrTiO₃ are perovskite compounds that display electrical conductivity which is a function of partial pressure of oxygen (po2). It has been proposed that acceptor-doped LaCrO₃ becomes highly resistive at low po2's due to ionic compensation of the acceptor-dopant present by oxygen vacancies. SrTiO₃ has been thought to absorb O₂ into a crystallographic shear structure and exsolve strontium vacancies which can then ionically compensate the La present and give a high resistance at high po2's.

Given these models, relationships between weight loss and conductivity vs. po₂ are developed for both these …

Applications Of Finite And Wave Envelope Element Approximations To Acoustic Radiation From Turbofan Engine Inlets In Flight, A. V. Parrett

Doctoral Dissertations

"The problem of acoustic radiation from turbofan engine inlets in flow has not lent itself fully to analysis by numerical means because of the large domains and high frequencies involved. This project has extended the use of finite elements and wave envelope elements, elements which simulate decay and wavelike behaviour in their interpolation functions, from the no-flow case in which they have been proven, to cases incorporating mean flow. By employing an irrotational mean flow assumption, the acoustics problem has been posed in an axisymmetric formulation in terms of acoustic velocity potential, thus minimising computer solution storage requirements. The wave …

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 …

A Study Of The Permeability Of Clays Subjected To Organic And Inorganic Permeants, Janardanan O. Uppot

Doctoral Dissertations

"Two types of clays, a magnesium montrnorillonite and a kaolinite, were subjected to precise permeability tests in specially designed triaxial permeameters, using organic and inorgani c permeants, to study the changes in permeability due to the reaction between clays and permeants. The organic permeants were an acid (acetic acid), a base (aniline), a neutral polar fluid (methanol), a neutral nonpolar fluid (xylene), as well as EDTA and its sodium salt. The inorganic permeants were aqueous solutions of aluminum, magnesium, sodium, calcium, barium and strontium.

The clay samples were prepared by consolidating from slurry; they were subjected to back-pressure saturation and …

Testing Of Steel Roof Deck Construction, Wei-Wen Yu, Lan-Cheng Pan, S. H. Lin

CCFSS Library (1939 - present)

INTRODUCTION In recent years, insulated steel roof deck construction has been widely used in industrial and commercial buildings. The use of roof assembly consisting of 3-in. deep, 22-gage, steel deck is being considered by Rooftex, Inc. of Houston, Texas, for Class 1-60 and Class 1-90 assemblies. At the request of Rooftex, two types of tests were conducted at the University of Missouri-Rolla in July 1983. These tests, which consisted of physical tests of steel roof decks and uplift pressure tests of insulated steel roof deck construction, were conducted to obtain the"necessary data for the approval of the Factory Mutual Research …

Laterally Unsupported Purlins Subjected To Uplift, Roger A. Laboube

CCFSS Library (1939 - present)

INTRODUCTION A research study, conducted at Cornell University, provided a theoretical method for evaluating the state of stress for both C- and Z- purlins subjected to wind uplift loading. According to the Cornell analytical method, a Z-purlin has more load carrying capability than a similar C-purlin. Although experimental verification was provided, questions were raised, within the Metal Building Industry, regarding the strength of the C-versus the Z-section. The purpose of the work discussed herein was to develop information regarding the behavior of C- and Z-sections having identical cross-section dimensions. A brief description of the test program, along with a comparison …

The Effects Of Certain Impurities And Their Interactions On Zinc Electrowinning, Donald R. Fosnacht, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The effects of germanium, antimony, arsenic, cobalt, glue, and free acid concentration were studied on both commercial and synthetic electrolytes. The effects of a single factor and the combined effects of multiple factors were elucidated. The temperature, zinc concentration, and current density were varied for some of the tests. It was found that the acid content was the most critical factor when impurity levels were at normal plant solution concentrations. The ranges where the effect of the impurity became apparent were: greater than 20 ppb (parts per billion) for antimony; 40 ppb for germanium; 120 ppb for arsenic; and 7 …

Limiting Efficiencies For Multiple Energy-Gap Quantum Devices, Cheng-Hsiao Wu, Richard M. Williams

Electrical and Computer Engineering Faculty Research & Creative Works

We have used a thermodynamic model to calculate theoretical limiting efficiencies for simple and multiple gap solar cells. The limiting efficiency is 26% for a simple solar cell of hydrogenated amorphous silicon, operating at one Sun sensitivity. For a multiple gap cell made from hydrogenated amorphous silicon, together with a second cell, made from a material with lower band gap, it is 38%. The optimum band gap for the second material is 1.0 eV.

Screening Design Test For Cobalt Cementation From Zinc Electrolyte, Mark S. Blaser, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Testing Of Steel Roof Deck Construction, S. Sucharit, Lan-Cheng Pan

CCFSS Library (1939 - present)

No abstract provided.

Design Of Automotive Structural Components Using High Strength Sheet Steels Preliminary Study Of Members Consisting Of Flat And Curved Elements, Wei-Wen Yu, M. Brad Parks

CCFSS Library (1939 - present)

No abstract provided.

Design Of Automotive Structural Components Using High Strength Sheet Steels-Strength Of Beam Webs, Chiravut Santaputra, Wei-Wen Yu

CCFSS Library (1939 - present)

I. INTRODUCTION In February 1981, the "Guide for Preliminary Design of Sheet Steel Automotive Structural Components" was issued by American Iron and Steel Institute (AISI) for assisting automotive structural designers to achieve weight reduction through the efficient utilization of carbon and high strength steels. 1 These design recommendations were based primarily on the 1968 Edition of the AISI "Specification for the Design of Cold-Formed Steel Structural Hembers,,2 but contained the following major differences with regard to the AISI Specification, which was written 'for the design of buildings: 1,4 a. The design expressions presented in the Guide are based on an …

Control Of Oxygen And Carbon Related Crystal Defects In Silicon Processing, P. D. Ownby, P. E. Grayson

Materials Science and Engineering Faculty Research & Creative Works

In the production of silicon articles at an elevated temperature, a stream comprising a controlled mixture of an oxygen-containing first gas and a second gas is admitted to the processing chamber. The first gas is one which partially dissociates under the conditions in the chamber to form both oxygen and the second gas. The second gas is one which is not harmful to silicon at the conditions in the chamber. Substantially equilibrium conditions are established in the chamber so that the dissociation of the first gas to oxygen occurs reversibly. The partial pressure of oxygen (P_O2) is sensed …

Saint-Venant's Principle In Linear Elasticity With Microstructure, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Toupin's version of the Saint-Venant principle in linear elasticity is generalized to the case of linear elasticity with microstructure. That is, it is shown that, for a straight prismatic bar made of an isotropic linear elastic material with microstructure and loaded by a self-equilibrated force system at one end only, the strain energy stored in the portion of the bar which is beyond a distance s from the loaded end decreases exponentially with the distance s. © 1983 Martinus Nijhoff Publishers.

The Influence Of Local Buckling On The Structural Behavior Of Singly-Symmetric Cold-Formed Steel Columns, Gale P. Mulligan, Teoman Peköz

CCFSS Library (1939 - present)

INTRODUCTION Cold-formed steel sections are formed from thin steel sheets, of typical thickness 0.015-0.25 inches, by either production cold roll forming or by specialized press braking. As a result, it is possible to produce economically a variety of cross-sectional shapes, which have high strength-to-weight ratios. Some structural applications include primary and secondary load-carrying framing members, such as columns, purlins and wall studs; and shear diaphragms, such as floor and roof decks and wall panels (Yu [1973]). Their design is governed by the American Iron and Steel Institute (AISI) Specification [1980], which is unique because of its generality, e.g., no specific …

Cold-Formed Steel Design Manual, American Iron And Steel Institute

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

No abstract provided.

Design Of Automotive Structural Components Using High Strength Sheet Steels, Wei-Wen Yu, Chiravut Santaputra, M. Brad Parks

CCFSS Library (1939 - present)

INTRODUCTION In recent years, automobile manufacturers have introduced new lines of lighter vehicles for the purpose of achieving fuel economy. To construct such vehicles, formable and weldable, high strength, sheet steels with yield points ranging up to 140 ksi have been used for parts and structural components. 1.1-1.7 Because various types of newer high strength sheet steels are now available for engineers to reduce car weight and because these steels permit the use of existing production equipment with virtually no change in techniques or production rates, the design criteria for efficient and economical use of these high strength steels in …

Repetitive Load Deformation Of Cohesionless Soil, Rodney Lentz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Energy Storage Capacity Of Reversible Liquid‐Phase Diels Alder Reaction Between Maleic Anhydride And 2‐Methyl Furan, B. G. Sparks, Bruce E. Poling

Chemical and Biochemical Engineering Faculty Research & Creative Works

Calorimetry was used to determine the heat of reaction and equilibrium constant at 318 K for the reaction between maleic anhydride (A) and 2‐methyl furan (B). The values were −60 kJ/gmol and 614 cm3/gmol, respectively. The motivation for this work was to find a single phase‐reacting system that could be used to store solar energy. Thus, the energy storage capacity was calculated for a mixture of A and B, both initially at 7 kmol/m3, in dioxane. The maximum apparent heat capacity of 7.37 J/cm3·K occurred at 334 K. This maximum value is 76% higher than the heat capacity of pure …

Line-Adaptive Hybrid Coding Of Images, Tai On Tam, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Describes Novel Adaptation Strategy for Hybrid Transform/DPCM Image Coders. This Strategy Has Yielded a 2–8 DB Increase in Signal-To-Noise Ratio in the Transmission of a Head and Shoulders Image at Bit Rates of 1–4 Bits Per Pel and One-Dimensional Transform Block Sizes of 2–16. © 1983 IEEE

Improved Wavenumber Resolution For Small Arrays, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The Objective of the Method Described is to Compute the Fourier Transform of a Function of Space and Time with a Significant Improvement in the Resolution of Spatial Frequencies, particularly in the Case of Small Arrays for Which the Size of the Array is on the Order of One Wavelength (Or less). This Improvement is Initially Developed by Considering the Conversion of Spatial Frequency into Temporal Frequency through the Oscillatory Motion of a Single Receiver. a More Practical Scheme is Next Presented in Which the Oscillatory Motion is Created Synthetically by the Appropriate Sequential Sampling of Individual Elements in a …