Engineering Commons^™

Solution To Eigenvalue Problems Of Antisymmetric Cross-Ply And Antisymmetric Angle-Ply Laminated Plates Using Affine Transformations, Zaffir A. Chaudry

Theses and Dissertations

Using affine transformations and suitably recasting the buckling vibration differential equations, the eigenvalue problem of anti-symmetric cross-ply and antisymmetric angle-ply laminated rectangular plates has been reduced to a function of two strong material constants, the generalized rigidity ratio, whose range is in the closed interval from 0 to 1, and the ratio of principal lamina stiffness. With the reduction in number of constants an exhaustive parameter study of buckling and vibration solution trends, is possible. The buckling coefficients decrease with decreasing value of generalized rigidity ratio for both antisymmetric cross-ply and antisymmetric angle-ply laminates. For a given aspect ratio, and …

Study Of Longitudinal Landing Flying Qualities Evaluation Using Pilot Model Theory, Eric D. Didomenico

Theses and Dissertations

Control Anticipation Parameter (CAP), used in MIL-SPEC-8785C as a longitudinal handling qualities criterion does not adequately distinguish between different flight phases. Recent flight test data from the Landing Approach Higher Order Systems (LAHOS) study further indicate the inadequacy of the second order approximations for higher order longitudinal landing flying qualities. Nine Aircraft that fall within the Level 1 boundary reveal pilot ratings ranging from 1.5 to 10 (Cooper/Harper). These nine aircraft are studied by combining their longitudinal dynamics with pilot modelling to examine a better method of landing flying quality prediction and evaluation. Pilot model theory (cross-over pilot model) is …

Application Of Combined Jointed Media And Discrete Slip Plane Characteristics To Subsidence Predictions, David W. Basinger

Theses and Dissertations

This thesis presents an application of a numerical formulation incorporating the effects of joints, cracks, and fractures to a soil subsidence predictions problem, and the extension of that formulation to combined discrete slip planes and jointed media continua formulations. The results obtained are compared to each other and to a physical centrifuge simulation performed previously on the same problem.

Measurement Of Air Force Fire Department Productivity: An Evaluation Of Efficiency/Effectiveness, Timothy A. Byers, Susanne M. Waylette

Theses and Dissertations

This research was sponsored to develop a method of evaluating the productivity of Air Force Fire Departments. Using the tasks developed by the Fire Department Workshop, input and output measures were defined and used in a new model of efficiency called Constrained Facet Analysis (CFA). The advantage of this methodology over others considered was that it can simultaneously evaluate multiple inputs and multiple outputs using empirical data with no a priori weighting. The results of the analysis provided an efficiency rating for each fire department and information about marginal rates of substitution and marginal rates of productivity for inefficient units …

Planning For The On-Orbit Servicing Of Military Spacecraft, Michael E. Russell, Robert M. Tayloe

Theses and Dissertations

On-orbit spacecraft servicing for military programs is examined. The military community appears to be somewhat reticent to embrace or, in some cases, to even consider on-orbit servicing. The civilian community appears enthusiastic about the potential of on-orbit servicing and the majority of economic studies of civilian missions show servicing strategies to be an attractive alternative to most expendable spacecraft strategies. A model called SATSERV is presented. This model can be used to conduct economic comparisons from an overall standpoint between expendable and servicing strategies. The model is implemented in a microcomputer spreadsheet format for rapid implementation and application along with …

Stochastic Estimation Applied To The Land Speed Of Sound Record Attempt By A Rocket Car, David A. Reinholz

Theses and Dissertations

Optimal linear smoothing theory is applied to the data from the Speed of Sound record attempt of a three-wheeled rocket car on 17 December 1979. A forward-backward estimation method is used which employs a seven state forward-running extended Kalman filter and a Meditch-form backward recursive 'fixed-interval' smoothing algorithm. Data for this analysis is supplied by a longitudinal accelerometer mounted on the vehicle and tracking radar measurements of range, azimuth, and elevation. States of interest include two components of vehicle position and velocity, accelerometer time-correlated error, and radar range and azimuth bias errors. Two iterations of the forward-backward smoothing algorithm provide …

Two-Dimensional Computer Modeling Of Joints And Fractures In Continua, Royd R. Nelson

Theses and Dissertations

This thesis presents a numerical formulation which incorporates the effects of joints, cracks, and fractures into a mathematical mode used to in an existing finite element code. Two separate crack definitions were incorporated, one involving a discrete crack model, and the other a continuum approach defining a new material with regularly spaced joints. Several examples are also presented demonstrating the use of this capability.

Development Of A Computer-Aided Graphics Capability To Display Field Test Data, L. Allen Adams

Theses and Dissertations

This thesis develops an interactive computer-aided graphics package for the display of experimental and field test data. EXPERT was developed to be used in conjunction with MOVIE.BYU and DISSPLA, utilizing a bivariate interpolation scheme to create a full field of data using the "sparse" field data as pivotal points. The usefulness and practicality of the program is demonstrated by graphically displaying the data from the Air Force Weapons Laboratory's CHEAT test.

Development Of A Computer-Aided Analysis Package For Linear Elastic Fracture Mechanics, William E. Warkentin

Theses and Dissertations

This thesis develops an interactive computer-aided analysis package for solving linear elastic fracture mechanics problems. CHILES 2 (an existing finite element fracture mechanics program) was modified to be interactive. The modified program is named CHILES.BYU and is used in conjunction with QMESH.BYU and MOVIE.BYU to form the total software package. An analysis of glass ceramics and glass ceramic/metal interfaces was performed demonstrating the capabilities of the package. This study demonstrates the usefulness of an interactive package of computer programs to allow an engineer to rapidly investigate different crack configurations.

Scrubs.Byu A Two Dimensional Finite Element Package For Continuum Analysis Using Quadratic Isoparametric Elements, Michael Glenn Long

Theses and Dissertations

This thesis develops a two dimensional, axisymmetric finite element package for solving continuum problems including rubbleization subsidence and nonlinear fracture mechanics. This package includes both a user friendly preprocessor, PRESCRUBS.BYU, and a versatile analysis code SCRUBS.BYU. PRESCRUBS.BYU systematically creates the data file necessary to run SCRUBS.BYU. SCRUBS.BYU provides many options of nonlinear static analysis using either linear or quadratic isoparametric finite elements. Sample problems are presented that demonstrate the capabilities of this package.

Microfit : A Gate Level Logic Simulator, Yacoub Abraham Alsaka

Theses and Dissertations

Today, gate logic simulation requires large computer facilities. This thesis demonstrates the ability to implement a gate logic simulator in a limited memory environment, specifically in a microcomputer system which usually has limited memory space; at the same time with a reasonable response time. This will permit the use of gate level simulation as a powerful design tool implemented with limited resources or with a desk-top microcomputer. The thesis discusses the development of the MICROFIT logic simulator. The MICROFIT would be used by the students and implemented on the LSI-11 Microcomputer Systems in the Assembly Language Laboratory at Florida Institute …

A Preliminary Investigation Of Physical-Chemical Treatment Of Slagging Gasifier Aqueous Effluent, Kirk B. Hird

Theses and Dissertations

The feasibility of treating slagging gasifier wastewater by physical-chemical means was studied. Pretreatment and treatment flow schemes were developed by using batch and continuous tests. Results were based mainly on wastewater residual total organic carbon (TOC). A treatment facility was designed and economically evaluated.

It was found that slagging gasifier wastewater is treatable by physical-chemical means using activated carbon and chemical oxidation as the two principal treatment steps. A pretreatment scheme consisting of lime addition, ammonia stripping, and recarbonation-coagu- lation was found to sufficiently purify the raw gasifier liquor so that activated carbon adsorption and chemical oxidation could be applied …

A Study Of A Wind Tunnel Measurement System For Unsteady Pressures Using Pneumatic Transmission Lines, Mohammed Javed Khan

Theses and Dissertations

The application of pneumatic transmission lines theory to a tube-scanning valve system for unsteady pressure measurements in the AFIT 5-foot wind tunnel is investigated. Transfer gains of various tube-scanning valve configurations were experimentally measured and the validity of a theoretical model verified for a frequency range of 20 Hz to 140 Hz. The selected system having a 0.0625-in. ID flexible tube of 84 in. length connected to a scanning valve was installed in the wind tunnel. Unsteady pressures introduced over an 18 percent airfoil at zero angle of attack were measured with this system. Data were collected for 0, 40, …

Computer Graphics: Conversion Of Contour Line Definitions Into Polygonal Element Mosaics, Thomas W. Sederberg

Theses and Dissertations

There has been a disparity between the conventional method of describing topographic surfaces (i.e. contour line definition) and a format of surface description often used in continuous-line computer graphics (i.e. panel definition). The two differ enough that conversion from contours to panels is not a trivial problem. A computer program that performs such a conversion would greatly facilitate continuous tone display of topographical surfaces, or any other surface which is defined by contour lines.

This problem has been addressed by Keppel and alluded to by Fuchs. Keppel's is a highly systematic approach in which he uses graph theory to find …

Sensitivity Of Process Variables On Rigid Polyurethane Foaming, Bruce A. Pugsley

Theses and Dissertations

Inadequate understanding and/or control of the polyurethane rigid foam process normally requires five to ten percent overpack of cavities to obtain correct fill and foam characteristics. This practice of overpacking has resulted in excessive waste and cost.

An Improved Fission Product Pressure Model For Use In The Venus-Ii Disassembly Code, Ray Leland Jensen

Theses and Dissertations

The world's growing need for safe, reliable, and long-term energy sources has intensified the research being conducted in the development of nuclear power. The operation of power reactors is contingent upon the continued availability of the fissile material required to maintain a critic a l reactor. The only naturally occuring fissile material is an isotope of uranium, U-235, which only accounts for 0.76 percent of the uranium that is mined. Due to the relative scarcity of this important fissile material it is estimated the United States' sources of economically recoverable fissile material will be delinquished with in about twenty-five years.^1

Steady-State Fluidics: Computer-Aided Analysis Of Analog Fluidic Circuits By Use Of Experimentally Determined Characteristic Curves, Raymond P. Martin Jr.

Theses and Dissertations

One of the fundamental tasks confronting engineers is the transmission and control of energy. The engineer, faced with this requirement and influenced by details of a specific, situation, his education and experience, and the customer's desires, will probably select a mechanical, electrical, or electro-mechanical system. Often a better choice exists—the use of a fluid power system. Fluid power systems employ pressurized fluids, liquids and/or gases, to transmit and control energy. Hydraulic systems use liquids, usually special oils or treated water. Pneumatic. systems use air or other gases. Both types are versatile and find a wide range of application.

Steady State Fluidics: The Static Matching Of Fluidic Amplifiers And Loads, Frank J. Redd

Theses and Dissertations

"Fluidics" is the title applied to a relatively new technology which is concerned with the control of fluid power and the processing of information through the use of the fluid mechanical properties of the fluid medium itself. The absence of moving parts and the relatively low sensitivity to enviromental conditions suggest the probability that fluidic systems will prove to be faster and more reliable than the mechanically controlled (valves, diaphragms, springs, etc.) fluid systems which they are designed to replace.

Alcohol Assisted Hydrocarbon Fuels: A Comparison Of Exhaust Emissions, Power Output And Fuel Consumption Using Static And Dynamic Engine Test Facilities, Dwight J. Bushnell

Theses and Dissertations

America’s energy crunch— something new for a country that has been used to great affluence. America’s smog— an eye stinging, lung burning situation which the Environmental Protection Agency has "promised" to rectify. These are two outstanding problems that face the engineer and scientist of today. The end of the era of cheap gasoline has brought the beginnings of a quiet revolution to Detroit: an improvement in the efficiency, economy and emission level of the American automobile. Word has penetrated to the automotive engineers that the emissions level, fuel economy and automobile safety are the prime design considerations for the automobile …

Determination Of The Most Economically Feasible Method For High Volume Machining Of A Discharge Port In A Powder-Metal Compressor Cylinder, Perry W. Carter

Theses and Dissertations

The purpose of this study was to ascertain the most economically feasible method for high volume machining of a discharge hole in a power metal compressor cylinder.

Silver Centers Induced In Borate Glasses, Wagdi Youssef Rabbat

Theses and Dissertations

Thesis presented to the Department of Materials Engineering and Physical Sciences.

Thesis (M.A.)--American University in Cairo, 1974.

Faa/Dod Liaison In Management Of The National Aviation System, Ronald S. Brooks, Jerry L. Beatty

Theses and Dissertations

This study describes and analyzes military and FAA liaison efforts which impact on the management of the National Aviation System. It begins with the historical development of the National Airspace System (NAS), The system is evolutionary in nature and most innovations have come from user demands and outside sources, Long term government responsibility to manage the system has been secondary to the operation and maintenance functions, There has been duplication of effort due to poor coordination on developing common goals, The military has been the leader in developing technology that led to improvement of the system.

Transient Convective Heat Transfer In Closed Containers During And After Gas Injection, Jennings Donell Means

Theses and Dissertations

This dissertation presents experimental data correlations for the spatially - averaged convective heat transfer coefficient for thin walled closed containers during and after gas injection. The different modes of heat transfer were identified, and correlations were made for each. Correlations are presented for the injection period, post-top injection, post-bottom injection, post- tangential, post-radial injection, and post-ejection heat transfer for various tank geometries. Of special significance are the very high heat transfer rates that were shown to be present in some cases immediately after injection. Heat transfer rates were shown to be, for a short period, up to almost two orders …

Analysis Of Heat Generation And Temperature In High Speed, High Temperature Bearing Balls, Hans R. Ringger

Theses and Dissertations

This thesis reports an investigation of the generation of heat on, and the prediction of temperature of high-speed, dry-film lubricated, stainless steel bearing balls.

The Design And Analysis Of An Electro-Pneumatic Signal Converter, Richard K. Thornton

Theses and Dissertations

In the field of process control it is desirable to study dynamic characteristics such as frequency response and distortion when determining just how equipment is to be controlled. Pneumatic controllers, transmitters, control valves, etc., all have dynamic behaviors which can be expressed mathematically as transfer functions. Each component plays an important role in determining the entire system behavior. Frequency response is one technique used in developing a component’s transfer function. By driving a device with a sinusoidal signal of fixed amplitude and frequency the output amplitude and phase shift are measured and compared with that of the input. Varying the …

Finite Conductance Element Method Of Conduction Heat Transfer, E. Clark Lemmon

Theses and Dissertations

One of the basic goals in engineering is to formulate models which will provide a means for analytically predicting observed phenomenon. For some time, the partial differential equations describing the steady state and transient conduction of heat within a solid have been available. However, the straight forward use of these equations is often restricted due to the surface geometry of the solid. If the surface geometry is at all irregular, exact solutions will in general not exist. In that case, a solution is sought by some approximate numerical technique. The two techniques most often used are the finite difference method …

An Aerodynamic Investigation Of The Causes Of Overhead Electrical Transmission Line Gallop, Eric Nathan Skousen

Theses and Dissertations

Overhead electrical transmission lines vibrate due to the action of a prevailing wind. These cable vibrations can be classified into two categories— high-frequency and low-frequency. The high-frequency vibrations, "aeolian" vibrations or "singing wires," is a low-amplitude phenomenon. It has been largely controlled with the use of various mechanical dampers [l, 2],

Measurement And Analysis Of Data In Turbulent And Transition Regions Of Two-Phase Flow, Akula Venkatram

Theses and Dissertations

The main aim of the project was to examine the possibility of using the hot wire anemometer to detect particles in a fluid. It was hoped that the presence of the particles would affect the autocorrelation plot and the energy spectrum of the velocities measured in the fluid.

Analysis Of A Microcircuit, Distributed Parameter Network, Which Considers Series Inductance And Shunt Conductance, Arun Jayantilal Shah

Theses and Dissertations

In this work analysis of distributed microcircuit is carried out including effects of series inductance and shunt conductance. General solution for voltage and current are obtained in terms of arbitrary constants which are to be determined by input and output conditions. Terminal voltages and terminal currents are expressed by Indefinite Admittance Matrix and port voltage, and port currents are expressed by Indefinite Impedance Matrix. Illustrative example is solved using indefinite matrix configuration and proper boundary conditions.

A Geographic Study Of Stone Houses In Selected Utah Communities, Barry M. Roth

Theses and Dissertations

This thesis will investigate the spatial location of stone houses and the areal differentiation of several characteristics of stone houses in selected communities. Some differences in cultural and historical factors and in types of building stone, quarries and quarrying techniques will be studied. The thesis will also investigate why stone houses are still in existence and things that owners, residents, and others like and dislike about them.