Engineering Commons^™

Investigation Of Damage Mechanisms In A Cross-Ply Metal Matrix Composite Under Thermo-Mechanical Loading, Joel J. Schubbe

Theses and Dissertations

Metal matrix composites (MMCs) are rapidly becoming strong candidates for high temperature and high stiffness structural applications such as the Advanced Tactical Fighter (ATF). This study systematically investigated the failure modes and associated damage in a cross-ply, [0/90]_2s SCS6/Ti-15-3 metal matrix composite under in-phase and out-of-phase thermomechanic fatigue. Initiation and progression of fatigue damage were recorded and correlated to changes in Young's Modulus of the composite material. Experimental results show an internal stabilization of reaction zone size but degradation and separation from constituent materials under extended cyclic thermal loading. Critical to damage were transverse cracks initiating in the 90° …

Evaluation Of Geocomposite Pavement Panel Drains Installed In A Sand Backfill Under Revised Installation Specification, L. John Fleckenstein, David L. Allen

Kentucky Transportation Center Research Report

Prior to 1989, highway edge drains were backfilled with the existing trench material and dynamically compacted with a tamping shoe. The net result was damage to the inner core of the edge drain.

In response to these problems the installation specification was revised in 1989 to insure the integrity of the drainage system. The revised method of installation consisted of moving the panel to the shoulder side of the trench and then flushing a sand slurry into the trench for backfill. Flushing the sand eliminates the need for mechanical compaction.

Since 1989, two projects have been completed using the revised …

Evaluation Of Flexible Delineator Posts, Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

The objective of this study was to install a small number of lightweight metal u-channel posts with a round delineator and a small number of commonly used flexible posts and evaluate their performance. Three types of flexible posts were installed. They included two posts manufactured by Carsonite and one manufactured by Safe-Hit.

The results of the limited field tests does not support widespread use of flexible posts. Substantial durability problems were encountered with the flexible posts. Future use of flexible posts should be limited to potential high-hit areas such as gores at urban interchanges. While the durability of the metal …

Performance Evaluations Of Crushed Sandstone Aggregates In Bituminous Bases (Data Appendix To Report Ktc-90-26), David Q. Hunsucker, R. Clark Graves

Kentucky Transportation Center Research Report

The principal objective of the research effort was to develop historical performance data for bituminous sandstone pavements and bituminous limestone pavements relative to visual distress, pavement rutting characteristics, and structural condition using deflection measurements. Data relative to Road Rater deflections, pavement rutting, condition ratings based on subjective visual surveys and objective data such as skid resistance and rideability, were collected and analyzed during the course of the study and reported herein for the routes investigated.

It was concluded, based upon information gained during the evaluation period and presented in this report, that pavements constructed with bituminous sandstone bases do not …

Performance Evaluations Of Crushed Sandstone Aggregates In Bituminous Bases, David Q. Hunsucker, R. Clark Graves

Kentucky Transportation Center Research Report

The principal objective of the research effort was to develop historical performance data for bituminous sandstone pavements and bituminous limestone pavements relative to visual distress, pavement rutting characteristics, and structural condition using deflection measurements. Data relative to Road Rater deflections, pavement rutting, condition ratings based on subjective visual surveys and objective data such as skid resistance and rideability, were collected and analyzed during the course of the study and reported herein for the routes investigated.

It was concluded, based upon information gained during the evaluation period and presented in this report, that pavements constructed with bituminous sandstone bases do not …

Irish Building Services News

Building Services Engineering

No abstract provided.

Digital Signal Processing Schemes For Fiber Optic Rotation Rate Sensor Scale Factor Linearization, David T. Dembinski

Masters Theses

This study examined and evaluated several scale factor linearization techniques for a fiber optic rotation rate sensor (FORS). The process of scale factor linearization retrieves rotation rate from an FORS signal. Open and closed loop digital signal processing schemes are evaluated on dynamic range, accuracy, and cost.

The results of these experiments show that open loop schemes require few components but have an inherently low dynamic range of operation. Extending the dynamic range of an open loop system is expensive in additional components. Closed loop systems require more initial components, but have a considerably superior dynamic range. It was concluded …

An Ergonomic Study Of Meat Processing Operations, Edgar Delgado

Masters Theses

In this study, physical stresses imposed on the different parts of the musculoskeletal system were assessed using a subjective ratings of perceived discomfort (RPD) scale in the meat industry. The effects of a microbreak system on the perceived discomfort of employees were studied. In addition, a comparison of human physical capacities (i.e., anthropometric, strength, and endurance measures) for Caucasian-American and Hispanic-Mexican employees in the meat industry was performed. These measures were also compared against those of employees engaged in manual material handling tasks. Twenty-eight employees participated in the study.

Based on this study, it can be concluded that: (a) RPD …

Quantization Noise Characteristics Resulting From Gaussian, Negative- Exponential, And Sinusoidal Random Input Signals, Van N. Osborne

Theses and Dissertations

The purpose of this study was to investigate the trade-off between the number of quantization levels and the resulting noise characteristics for three classes of commonly occurring input signals, namely, those signals possessing Gaussian, negative-exponential and random sinusoidal distributions. This study derived expressions for the mean-squared error, output spectrum and error spectrum by expanding the nonlinear quantization function into a summation of orthogonal polynomials matched to the corresponding input signal distribution. Once accomplished, orthogonality properties were applied to provide usable expressions. A set of three Fortran 77 programs were developed- each of which applied to one of the studied input …

Effect Of Riblets On Pressure Recovery In A Straight-Walled Diffuser, Michael K. Reagan

Theses and Dissertations

The objective of this thesis was to investigate the effect of riblets on the pressure recovery in a straight-walled diffuser. Previous work has shown that riblets were effective in reducing the viscous drag over surfaces subjected to a turbulent boundary layer. More recently, riblets were shown to delay the flow separation within a subsonic, straight-walled diffuser by as much as 200%. The purpose of this investigation was to determine the effect on the pressure distribution within a diffuser that has had the flow separation point favorably altered by the application of riblets. Investigation results revealed that riblets not only delayed …

Sql/Nf Translator For The Triton Nested Relational Database System, Craig W. Schnepf

Theses and Dissertations

The problem addressed in this thesis concerns the design and implementation of a high level data base query language translator based on the nested relational data model. The objective of the model is to increase the performance of the relational model by modeling real-world objects in the problem domain into nested relations. The translator is designed within the EXODUS extensible architectural framework for building application-specific database systems. The SQL/NF query language used for the nested relational model is an extension of the popular relational model query language SQL. The query language is translated into a nested relational algebra (Colby algebra) …

Evaluation Of An Interdigitated Gate Electrode Field-Effect Transistor For Detecting Organophosphorus Compounds, Charles P. Brothers Jr.

Theses and Dissertations

This study used integrated circuit microsensors to detect organophosphorus compounds. Chemically-sensitive thin films, copper phthalocyanine, DFPase, succinyl chloride, succinylcholine chloride, 2- naphthol(B), and L-histidine dihydrochloride,were deposited on interdigitated gate electrode (IGE) structures, with an average thickness of 2000A. Thin film electrical performance characteristics were measured for several parameters, including: DC resistance, AC impedance, time-domain, and spectral responses from 10 Hz to 1 MHz. Each microsensor contained nine IGEs; each IGE possessed an in situ field-effect transistor amplifier. After purging each sensor with filtered air, it was exposed to one or two of the following gases: diisopropyl fluorophosphate (DFP), diisopropyl methylphosphonate, …

Investigation Of Fatigue Damage Mechanisms In A Metal Matrix Composite Under Elevated Temperature, Barry D. Portner

Theses and Dissertations

This study investigated the fatigue damage initiation and progression in SCS-6/Ti-15-3 under an environment of fatigue loading at isothermal temperature. This program included two parts. First, an 808 Ultimate Tensile Strength system was set up to accommodate testing at two frequencies of 2.0 and 0.0208 cps at a constant temperature of 427° C. Second, at intervals during the load cycle process, the test specimens were characterized by establishing damage parameters based on changing modulus of elasticity, average strain, strain range, and ultimate tensile strength. Damage progression was documented in the form of failure of the fiber-matrix interface, matrix cracking, fiber …

Characterization Of Sige/Si Heterostructures Formed By Ge+ And C+ Implantation, Akira Fukami, Ken-Ichi Shoji, Takahiro Nagano, Cary Y. Yang

Electrical and Computer Engineering

Formation of SiGe/Si heterostructures by germanium ion implantation was investigated. A germanium‐implanted layer was grown epitaxially in the solid phase by thermal annealing. Two kinds of crystalline defects were observed. One is a misfit dislocation, and the other is a residual dislocation caused by ion bombardment. The p‐n junction formed in the SiGe layer has a leakage current three orders of magnitude larger than that of a pure Si p‐n junction fabricated with an identical process except for the Ge+ implantation. Carbon doping in the SiGe layer improves its crystalline quality and the junction characteristics.

Radon Pressure Differential Project; Phase Ii Infiltration, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing has been done on 50 central Florida homes to assess and characterize house infiltration rates in new (age five years or less) Florida homes. These 50 were drawn randomly from a sample of 70 homes which had been previously tested to determine house airtightness, air distribution system leakage, and pressure differentials. The 50 homes had an average airtightness of 7.31 air changes per hour at 50 Pascals (ACH50). Significant leaks were found in the ductwork in a majority of homes tested, both on the supply and return sides of the air handler. When the air distribution system was sealed …

Radon Pressure Differential Project, Phase I, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing has been done on 70 central Florida homes to assess and characterize pressure differentials in new (age five years or less) Florida homes. Blower door testing was done to determine house airtightness and air distribution system leakage. The 70 homes had an average airtightness of 7.23 air changes per hour at 50 Pascals (ACH50). Significant leaks were found in the ductwork in a majority of homes tested, both on the supply and return sides of the air handler. When the air distribution system was sealed off, house ACH50 decreased to 6.42, indicating that 11.2% of the house leak area …

Appendix: List Of Participants [1990], Kentucky Transportation Center

Kentucky's Annual Forum on Transportation

No abstract provided.

Wrap-Up Luncheon [1990], Milo D. Bryant

Kentucky's Annual Forum on Transportation

No abstract provided.

Recruitment And Retention Of Transportation Professionals And Civil Engineers, O. Gilbert Newman

Kentucky's Annual Forum on Transportation

No abstract provided.

Kentucky Aviation And Economic Development, Michael Flack

Kentucky's Annual Forum on Transportation

No abstract provided.

Passenger Transit, Brenda Rice

Kentucky's Annual Forum on Transportation

No abstract provided.

Waterways Transportation, Dick Cirre

Kentucky's Annual Forum on Transportation

No abstract provided.

Kentucky's Transportation Needs For Economic Development, David E. Smith

Kentucky's Annual Forum on Transportation

No abstract provided.

General Session [1990], Eugene R. Mccormick

Kentucky's Annual Forum on Transportation

No abstract provided.

Segment Streaming For Efficient Pipelined Televisualization, Fengmin Gong

All Computer Science and Engineering Research

The importance of scientific visualization for both science and engineering endeavors has been well recognized. Televisualization becomes necessary because of the physical distribution of data, computation resources, and users involved in the visualization process. However, televisualization poses a number of challenges to the designers of communication protocols. A pipelined televisualization (PTV) model is proposed for efficient implementation of a class of visualization applications. Central to the proposed research is the development of a segment of streaming IPC (interprocess communication) mechanism in support of efficient pipelining across very high speed internetworks. This requires exploration of special issues arising from extending a …

Decomposition Of Measured Contours Into Geometric Features For Dimensional Inspection, Devaraj Rajkumar

Dissertations and Theses

Image processing systems used in Vision Assisted Dimensional Inspection usually output a set of boundary pixels representing the part edges. This boundary information must be divided into several subsets representing the various edges of the actual object, so that comparisons with the nominal part can be made.

The purpose of this project is to devise a method to divide the set of pixels obtained from the image processing system into subsets of pixels. Each of these subsets represent an edge in the contour of the actual object. This method must also detect transition points between the adjacent features. This project …

Automated Pavement Distress Surveys, John Hunt

Kentucky's Annual Forum on Transportation

No abstract provided.

Fast Track Concrete Paving, John Mcchord

Kentucky's Annual Forum on Transportation

No abstract provided.

Advantage I-75 Project, Jerry Lentz

Kentucky's Annual Forum on Transportation

No abstract provided.

Asphalt Materials, T. Scott Shuler

Kentucky's Annual Forum on Transportation

No abstract provided.