Engineering Commons^™

Improved Structural Monitoring With Acoustic Emission Pattern Recognition, David W. Prine, Theodore Hopwood Ii

Kentucky Transportation Center Research Report

A unique acoustic emission monitoring system originally developed for inprocess weld monitoring has been used to monitor fatigue crack growth in a highway bridge during normal traffic loading. The system was able to clearly and reliably detect the presence of fatigue cracks that were adjacent to a row of bolts. The results of the brief experiment show that the signal processing used in this AE system may allow drastic improvements in the ability of acoustic emission to reliably detect propagating bridge flaws under adverse conditions.

The Development Of A Computer Aided Design Program For Constant Group Delay Monolithic Crystal Filters, Michael A. Robitaille

Retrospective Theses and Dissertations

A computer program, which realizes monolithic crystal filters with constant group delay, is developed. This program analyzes and synthesizes a class of transfer functions developed by J.D. Rhodes called equidistant linear phase transfer functions. Using cascade synthesis, the program calculates the values of the inductor and capacitors of the ladder sections which realizes these functions. The ladder sections are implemented using monolithic crystal filters.

Development Of A Portable Retroreflectometer, Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

There is a need for a portable retroreflectometer which can perform reflectivity measurements in the field . This could eliminate the need for subjective ratings or taking samples of materials from the field to test in the laboratory. This report describes the development of a portable retroflectometer (PRR).

A PRR was built with the objective of approximating the angles of incidence and divergence used in the ESNA Reflex-Photometer (ESNA). Tests showed a good relationship between readings taken with the PRR and ESNA. The recommendation was made that the PRR is suitable for use as a means of measuring reflectivity in …

An Evaluation Of The 8051 Microcontroller, George C. Schafner

Retrospective Theses and Dissertations

With the increasing availability and use of 16-bit microprocessors, the 16-bit data bus and is becoming more prevalent. However, many peripheral devices such as printers and tape/disk drives still require an 8-bit data bus for their interface. This paper will explain how an Intel 8051 microcontroller may be used to interface a 16-bit data bus to a peripheral requiring an 8-bit data bus. A FIFO is used to buffer data from a 16-bit processor so that efficient use of processing time is maintained. The 8051 is used to control the peripheral and data transfer.

The Photovoltaic Cell: History, Operation, Current Technology, Marc L. Luksetich

Graduate Research Papers

Historically, practical applications of solar cells were of single crystal silicon material (Rauschenbach, 1980). In the mid 1970s, the U.S. Government actively began to subsidize solar cell development and use (Maycock & Stirewalt, 1981). This funding provided a major contribution for expanded research, development, and markets. Consequently, manufacturing and final-product costs have been reduced with a corresponding increase in solar cell efficiency (Merrigan, 1982). The main objective of this study was to analyze literature from photovoltaic cell manufacturers regarding their current production methods, materials, and uses, and to report the findings.

Shear Characteristics Of Motor Oils Conforming To The American Petroleum Institute's 1981 Engine Service Classification, D. Joseph Clausen

Graduate Research Papers

The problem was to determine if shear (slipperiness) characteristics differ between various SF motor oils. Oils tested met SAE (Society of Automotive Engineers) lOw-40 viscosity requirements, and API (American Petroleum Institute) engine service classification requirements for 1981 SF quality motor oils.

Four basic types of oil were tested: (a) mineral; (b) synthetic; (c) friction modified; and (d) extended drain. A gravity powered device was designed and used as a testing apparatus to measure force needed to pull a weight across a lubricated surface.

Findings indicated that friction modified oils (Pennzoil P-Z-L and Arcographite) were the most slippery. Other oils tested, …

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.

Motivation And The First Line Supervisor: A Survey Of Techniques And Applications, Raymond H. Rannfeldt

Graduate Research Papers

Do first line supervisors differ in their beliefs concerning motivation or in the techniques they employ to motivate their personnel as a function of age, time in service with a company and/or time as a supervisor?

Application Of The Method Of Lines For Solutions Of The Navier-Stokes Equations Using A Nonuniform Grid Distribution, Jamshid Samareh Abolhassani

Mechanical & Aerospace Engineering Theses & Dissertations

The feasibility of the method of lines is investigated for solutions of physical problems requiring nonuniform grid distributions. To attain this, it was also necessary to investigate the stiffness characteristics of the pertinent equations. For specific applications, the governing equations considered are those for viscous, incompressible, two-dimensional and axisymmetric flows. These equations are transform­ ed from the physical domain having a variable mesh to a computational domain with a uniform mesh. The two governing partial differential equations are the vorticity and stream function equations. The method of lines is used to solve the vorticity equation and the successive over relaxation …

Effect Of Transducer Size On The Statistical Properties Of A Simulated Turbulent Wall Pressure Field, Mehdi R. Khorrami

Mechanical & Aerospace Engineering Theses & Dissertations

The root mean square pressure was calculated with synthetically generated pressure signals for transducers of different size. The transducer diameters were in the range of 0.02 < _s*of 12,250. The lower limit of the diameter simulated here was much smaller than diameters reported previously by other workers. Calculated root mean square pressure levels developed in the present work were in good agreement with the measured experimental data.

In order to check the simulated pressure signals, the power spectrum and two point correlation were calculated as well. The power spectra obtained with the smaller transducers were higher in energy level at …

Viscous Modeling And Computation Of Leading-And Trailing-Edge Vortex Cores Of Delta Wings, Balakrishnan Lakshmanan

Mechanical & Aerospace Engineering Theses & Dissertations

A Finite-Difference method is presented for calculating steady quasi-axisymmetric flow of an incompressible fluid at large Reynolds number. Approximations of the boundary-layer type are employed to reduce the Navier-Stokes equations to a pair of non-linear parabolic equations. Along with the governing equations, initial conditions are specified at some upstream cross section and boundary conditions are specified at the axis of symmetry and on the outer bounding surface.

The governing equations are replaced by a set of quasilinear finite-difference equations. The solution is obtained by a marching technique, which proceeds step-by-step in the axial direction. At each axial station, an iterative …

Large Amplitude Free Flexural Vibrations Of Laminated Composite Plates Of Arbitrary Shape, Mo-How Shen

Mechanical & Aerospace Engineering Theses & Dissertations

A finite element formulation is presented for analyzing large amplitude free flexural vibrations of symmetrically laminated composite plates of arbitrary shape. Linear and nonlinear fundamental frequencies are determined from the analysis. The laminates are made of multiple generally or specially orthotropic layers and symmetrically disposed about the middle surface, hence there is no coupling between bending and extension. Linearized stiffness equations of motion governing large amplitude oscillations of laminates, linear element stiffness matrix, quasi-linear geometrical element stiffness matrix, and solution procedures are presented. The linearized geometrical stiffness matrix for a 18 degrees-of-freedom high precision triangular anisotropic plate element is evaluated …

On The Space Shuttle Wing Thermal-Structural Analysis, Kumar Krishna Tamma

Mechanical & Aerospace Engineering Theses & Dissertations

A finite element approach for efficient thermal-structural analysis of structures with thermal protection systems (TPS) is described. The approach is applied to Space Shuttle wing structure configurations subjected to reentry heating. New two and three-dimensional finite elements are developed to model heat transfer in the TPS and supporting structure. A typical TPS/Structural element predicts transient nonlinear temperature variations through the TPS thickness and detailed structural temperatures at the TPS/Structure interface. The accuracy of the TPS/Structure approach in two and three-dimensions is evaluated by comparisons with the conventional approach for various configurations of the wing structure. The results indicate that the …

Transient Two Dimensional Ground-Water Flow: A Comparison Of Computed And Analytical Results, Robert Jan Fennema

Civil & Environmental Engineering Theses & Dissertations

The exact analytical solution of the transient-flow equation is compared with the finite difference solution. The finite difference program, written by the author, uses an iterative alternating direction implicit procedure to solve the linearized partial differential equation. A second order accurate central difference method is employed to solve the equation in two dimensions.

Variable cell spacing to divide the physical domain, a weighting factor and a time acceleration function were used to investigate rate of convergence and accuracy of the numerical solution. The exact integral solution to the one-dimensional form of the flow equation i n radial coordinates is used …

Evaluating The Effects Of Alum With Polyelectrolyte Coagulant Aids In Treatment Of Low Turbidity Waters, Kenneth John Stockwell

Civil & Environmental Engineering Theses & Dissertations

Potable water sources usually require treatment for removal of suspended organic and inorganic particles. Conventional treatment processes incorporate chemical coagulants for removal of these suspended particles. Alum is a widely used coagulant that can provide adequate removals of turbidity. However, high alum dosages are required for treatment of low turbidity waters producing a voluminous sludge that is difficult to dewater.

Recent Federal regulations have limited disposal options for chemical sludges. This has prompted a reevaluation of coagulants and their dosages with the goal of reducing the amount of sludge produced and improving the sludge handling characteristics necessary for ultimate disposal. …

Biomass Gasifier Combustor, Frederick A. Payne, Ira J. Ross

Biosystems and Agricultural Engineering Faculty Patents

The present invention is directed to a biomass gasifier combustor which operates by gasification and combustion of the biomass to produce a clean effluent gas which can be used directly for grain drying or other applications where thermal energy is required. This biomass gasifier combustor burns crop residue clean enough so that the combustion gases can be used directly for grain drying without the need for a heat exchanger to isolate the combustion gases from the drying air. The biomass gasifier combustor includes a screw feeder tube having a screw feeder disposed therein. The screw feeder forces the biomass into …

Interstate Gas Pipeline Ratemaking And Contract Implications, Henry E. Brown

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

61 pages.

Contains references.

Contains 7 attachments.

Creditors’ Rights Involved In The Production And Sale Of Natural Gas, William M. Schultz

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

101 pages (includes forms).

Contains 6 attachments.

Section 311 And 312 Of The Natural Gas Policy Act Of 1978 And Hinshaw Pipelines, Lauren Eaton

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

5 pages.

Drafting And Interpreting Sensitive Gas Purchase Contract Provisions, William D. Watson

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

8 pages.

Off-System Sales: Will They Ever Return?, Paul F. O'Konski

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

5 pages.

Off-System Sales – Will They Ever Return? (The Interstate Side), Robert C. Mchugh

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

27 pages (includes illustrations).

Contains 2 pages of references.

Contains 1 attachment.

The Natural Gas Industry In Transition, Ruth A. Maurer

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

10 pages (includes illustrations).

Legislative Prospects For Wellhead Pricing Of Natural Gas, Richard G. Morgan

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

162 pages.

Contains 16 attachments.

Contractual And Other Considerations Affecting Producers, Pipelines And Distributors During Current Period Of Market Demand Constraints [Outline], Michael J. Manning

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

6 pages.

Agenda: Natural Gas Symposium: Contract Solutions For The Future Of Regulatory Environment, University Of Colorado Boulder. Natural Resources Law Center, University Of Houston. Law Center

Natural Gas Symposium: Contract Solutions for the Future of Regulatory Environment (March 24-25)

Contents:

The natural gas industry in transition / Ruth A. Maurer -- Legislative prospects for wellhead pricing of natural gas / Richard G. Morgan -- Off-system sales : will they ever return? : the interstate side / Robert C. McHugh -- Off-system sales : will they ever return? / Paul F. O'Konski -- Contractual and other considerations affecting producers, pipelines and distributors during current period of market demand constraints / Michael J. Manning -- Section 311 and 312 of the Natural Gas Policy Act of 1978 and Hinshaw pipelines / Lauren Eaton -- Drafting and interpreting sensitive gas purchase contract …

Gasification Of Densified Sludge And Wastepaper In A Downdraft Packed-Bed Gasifier, George Tchobanoglous, Nelson W. Sorbo, Samuel A. Vigil

Civil and Environmental Engineering

The co-disposal of densified sludge and wastepaper in a co-current flow packed bed gasifier represents new application of the thermal gasification process. Advantages of this technology include lower costs than other incineration or pyrolysis technologies, simple construction and operation, and the ability to use a variety of fuels including agricultural wastes and other biomass materials in addition to densified sludge and wastepaper.

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 …

Hydraulic Analysis Of Surcharged Storm Sewer Systems, Don J. Wood, Gregory C. Heitzman

KWRRI Research Reports

Surcharge in a storm sewer system is the condition in which an entire sewer section is submerged and the pipe is flowing full under pressure. Flow in a surcharged storm sewer is essentially slowly varying unsteady pipe flow and methods for analyzing this type of flow are investigated. In this report the governing equations for unsteady fluid flow in pressurized storm sewers are presented. From these governing equations three numerical models are developed using various assumptions and simplifications. These flow models are applied to several example storm sewer systems under surcharge conditions. Plots of hydraulic grade and flow throughout the …