Engineering Commons^™

Use Of Critical Chain Scheduling To Increase Aircraft Availability, Daniel D. Mattioda

Theses and Dissertations

This study addresses the operation and support cost differences between the TUAF C-130E & C-130B, and the USAF C-130J aircraft. The TUAF C-130s have been being used for more than 30 years and changing world situations give armed forces different roles, and Turkey participates in all peacekeeping missions that are assigned by NATO (North Atlantic Treaty Organization) and the United Nations. While performing these roles, the importance of air mobility and the importance of reliability became widely appreciated. Moreover, the coming retiring age of the existing C-130s in the TUAF forced the TUAF to look for ways to improve its …

An Evaluation Of The Hazard Prediction And Assessment Capability (Hpac) Software's Ability To Model The Chornobyl Accident, Dirk E. Plante

Theses and Dissertations

A parameter study was conducted for a space nuclear reactor radiation shield. The focus of this research was to explore alternatives to current radiation shield designs to reduce the mass while maintaining the same shielding performance. MCNP4C was used to determine the parameters necessary to build an optimum shield. A design known as the split scatter shield offered some potential for reductions in shield mass. In theory, less material is required for this type of shield, which uses thin shield sections to scatter radiation away from the dose plane. The parameters for this shield design are the shield geometry, number …

A Multiple Ant Colony Metaheuristic For The Air Refueling Tanker Assignment Problem, Ronjon Annaballi

Theses and Dissertations

The performance of the Nuclear Facility (NFAC) incident module in modeling a nuclear reactor accident is evaluated. Fallout predictions are compared with air concentration measurements of I-131 in Europe over a five-day period. Two categories of source term specifications are used: NFAC-generated source terms based on plant conditions and accident severity, and user-defined source terms based on specifying the release of I-131. The Atmospheric Transport Model Evaluation Study report source term provided the needed detailed release information. The Air Force Combat Climatology Center provided weather data covering Europe during the release's 11-day duration. For the NFAC-generated source terms as few …

An Examination Of Latency And Degradation Issues In Unmanned Combat Aerial Vehicle Environments, Shane A. Dougherty

Theses and Dissertations

Since the multidimensional knapsack problems are NP-hard problems, the exact solutions of knapsack problems often need excessive computing time and storage space. Thus, heuristic approaches are more practical for multidimensional knapsack problems as problems get large. This thesis presents the results of an empirical study of the performance of heuristic solution procedures based on the coefficients correlation structures and constraint slackness settings. In this thesis, the three representative greedy heuristics, Toyoda, Senju and Toyoda, and Loulou and Michaelides methods, are studied. The purpose of this thesis is to explore which heuristic of the three representative greedy heuristics perform best under …

Removal Of Antibiotics From Surface And Distilled Water In Conventional Water Treatment Processes, Craig D. Adams, Yang Wang, K. Loftin, M. Meyer

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Conventional drinking water treatment processes were evaluated under typical water treatment plant conditions to determine their effectiveness in the removal of seven common antibiotics: carbadox, sulfachlorpyridazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfathiazole, and trimethoprim. Experiments were conducted using synthetic solutions prepared by spiking both distilled/ deionized water and Missouri River water with the studied compounds. Sorption on Calgon WPH powdered activated carbon, reverse osmosis, and oxidation with chlorine and ozone under typical plant conditions were all shown to be effective in removing the studied antibiotics. Conversely, coagulation/flocculation/sedimentation with alum and iron salts, excess lime/soda ash softening, ultraviolet irradiation at disinfection dosages, and …

Safety Implications From Design Exceptions, Kenneth R. Agent, Jerry G. Pigman, Nikiforos Stamatiadis

Kentucky Transportation Center Research Report

The objectives of this study were to: a) summarize past design exceptions to document their frequency and reason for their use and b) determine if any adverse safety implications can be related to adopting design policies and practices related to design exceptions.

The design exception file maintained by the Kentucky Transportation Cabinet was obtained with data obtained relating to the types of project, exceptions requested, and the reasons for the various exceptions. A site visit was made to a large number of the locations where the project was built with the requested design exception. Available crash data were obtained at …

The Cost Of Construction Delays And Traffic Control For Life-Cycle Cost Analysis Of Pavements, Brad Rister, Clark Graves

Kentucky Transportation Center Research Report

The objective of this report is to provide the Kentucky Transportation Cabinet a reliable approach to quantifying/calculating “Road User Cost”--often referred to as total user delay costs. To meet this objective, this re port is divided into three main sections. The first section summarizes the reviews of three relatively new computer programs that can be used to help quantify delayed traffic incurred by the presence of a work zone. From this review, one program was selected based on it’s user friendliness and ability to define both quantity of delayed traffic and queue length. The second section compares actual field data …

Compaction At The Longitudinal Construction Joint In Asphalt Pavements (Kyspr-00-208), L. John Fleckenstein, David L. Allen, David B. Schultz Jr.

Kentucky Transportation Center Research Report

The objectives of this study were to evaluate the level of compaction at the construction joint in HMA pavements on new and existing projects; to determine the level of water infiltration and segregation at the joint and its effect on joint performance; to determine the most promising joint construction methods around the nation and worldwide by reviewing specifications, experiences, and construction practices for joint construction and the prevention of joint segregation; to develop specifications and construction methods to ensure the level of density necessary at the joint for proper performance; and to review special paving equipment (attachments) for improving densification …

Evaluation Of High Traffic Crash Corridors, Eric R. Green, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objectives of this study were to: a) determine a procedure to use to identify corridors in each highway district for which a detailed analysis of crash data should be conducted (with resulting increased law enforcement activities, education programs and engineering improvement s); b) develop a procedure to use to analyze the crash data and recommend countermeasures; and c) conduct a case study analysis for one selected corridor.

A method which could be used to select high crash corridors, by highway district, was developed. The procedure involved: obtaining a list of rout es in each district which traveled through more …

A 3-D Finite Element Structural Model Of An Instrumental Rigid Pavement (I-265 Gene Snyder Freeway, Louisville, Kentucky), Kamyar C. Mahboub, David L. Allen, Yinhui Liu

Kentucky Transportation Center Research Report

Field data that were generated from a section of concrete pavement on Gene Snyder Freeway (I-265), Louisville, Kentucky, were closely examined. An important conclusion of the field data examination was that the response produced by environmental load was more significant than traffic load and static load. To predict the mechanical behavior of the rigid pavement, a finite element model was developed for the project using the ANSYS program. The parametric study of the FEA model showed that the stiffness of subbase and subgrade had the most important effect on the mechanical response of the rigid pavement. On the basis of …

The Proceedings Of The Nasa Aerospace Technology Symposium 2002, Brent D. Bowen, Mary M. Fink, Michaela M. Schaaf, Uno Aviation Institute

Faculty Books and Monographs

UNOAI Report 02-4

A Simple Dynamics Experiment Based On Acoustic Emission, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper describes a simple experiment well suited for an undergraduate course in mechanical measurements and/or dynamics, in which physical information is extracted from an acoustic emission signature. In the experiment, a ping–pong ball is dropped onto a hard table surface and the audio signal resulting from the ball–table impacts is recorded. The times between successive bounces, or “flight times”, are used to determine the height of the initial drop and the coefficient of restitution of the impact. The experiment prompts questions about modeling the dynamics of a simple impact problem, including the use of the coefficient of restitution and …

Review Of: Eat Your Genes: How Genetically Modified Food Is Entering Our Diet (Stephen Nottingham Ed.), Natalie Duval

RISK: Health, Safety & Environment (1990-2002)

Review of the book: "Eat Your Genes: How Genetically Modified Food Is Entering Our Diet," by Stephen Nottingham, (St. Martin's Press 1999). Introduction, Glossary, Bibliography, Index. ISBN 1-85649-578-7 [212 pp. $17.95. Softbound, St. Martin's Press, Inc., New York, NY 10010].

Friction Of Wheat: Grain-On-Grain And On Corrugated Steel, Marek Molenda, Jozef Horabik, I. Joe Ross, Michael D. Montross

Biosystems and Agricultural Engineering Faculty Publications

Coefficients of friction of wheat for grain–on–grain and on galvanized corrugated steel sheet were investigated using a modified direct shear apparatus. Tests were conducted under a normal pressure of 20.7 kPa using soft red winter wheat at a moisture content of 11.2% (w.b.) and an uncompressed bulk density of 740 kg/m³. Three consolidation procedures and three methods of deposition of grain in the test chamber were used. Test results of grain–on–grain friction showed that consolidation procedure markedly influenced the force–displacement relationship, while its influence on the coefficients of friction were small. Shearing to peak strength as a consolidation …

2002 Directory Of Indiana State, County, City And Town Officials Responsible For Road And Street Work, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Directory

Contact information for agency officials and employees responsible for Indiana’s local road infrastructure.

Bs News

Building Services Engineering

No abstract provided.

Top Bar Effects In Prestressed Concrete Piles, Baolin Wan, Michael F. Petrou, Kent A. Harries, Aly A. Hussein

Civil and Environmental Engineering Faculty Research and Publications

The top bar effect in reinforced concrete is a widely recognized phenomenon. Currently, the ACI Building Code prescribes a 30% increase in the development length of top cast reinforcing bars. No such provision is required for strands in prestressed concrete members. In this paper, the top bar effect for prestressing strands is introduced. Parameters affecting top bar phenomena in prestressed concrete piles are identified, and strategies for reducing this effect are presented. Finally, for the first time, the application of a top bar effect factor for prestressed concrete development length calculations, similar to the one applied in reinforced concrete structural …

Supporting The Development And External Review Of Course Portfolios, Paul Savory, Dan Bernstein, John Comer, Jennifer Robinson

Department of Industrial and Management Systems Engineering: Faculty Publications

This presentation introduces the Peer Review of Teaching project for the University of Nebraska-Lincoln. The faculty fellowship program is described and the process by which faculty create course portfolios is explained. How portfolios are used for formative and summative assessment are discussed.

Thermodynamics And Bioenergetics, Yaşar Demirel, Stanley I. Sandler

Papers in Thermal Mechanics

Bioenergetics is concerned with the energy conservation and conversion processes in a living cell, particularly in the inner membrane of the mitochondrion. This review summarizes the role of thermodynamics in understanding the coupling between the chemical reactions and the transport of substances in bioenergetics. Thermodynamics has the advantages of identifying possible pathways, providing a measure of the efficiency of energy conversion, and of the coupling between various processes without requiring a detailed knowledge of the underlying mechanisms. In the last five decades, various new approaches in thermodynamics, non-equilibrium thermodynamics and network thermodynamics have been developed to understand the transport and …

Investigation Of Cooperative Behavior In Autonomous Wide Search Munitions, Robert E. Dunkel Iii

Theses and Dissertations

The purpose of this research is to investigate the effectiveness of wide-area search munitions in various scenarios using different cooperative behavior algorithms. The general scenario involves multiple autonomous munitions searching for an unknown number of targets of different priority in unknown locations. Three cooperative behavior algorithms are used in each scenario: no cooperation, cooperative attack only, and cooperative classification and attack. In the cooperative cases, the munitions allocate tasks on-line as a group, using linear programming techniques to determine the optimum allocation. Each munition provides inputs to the task allocation routine in the form of probabilities of successfully being able …

Analysis Of Air Force Contingency Contracting Training Needs, Peter S. Lasch

Theses and Dissertations

This research examines the Air Force training needs of contingency contracting officers (CCOs). The study utilized the deductive approach to research. A survey instrument captured the data for the study. The survey captured input from CCOs with deployment experience and each of the Air Force components and MAJCOMs. Series 1 of the survey polls CCOs with deployment experience to determine the training CCOs require based on their personal experiences. Series 2 surveys the component and MAJCOM level supervisors to determine their perception of the training that should be required for CCOs. Comparing the two series will identify any differences in …

Performance Evaluation Of Hyperbolic Position Location Technique In Cellular Wireless Networks, Hakan Senturk

Theses and Dissertations

This study addresses the wireless geolocation problem that has been an attractive subject for the last few years after Federal Communications Commission (FCC) mandate for wireless service providers to locate emergency 911 users with a high degree of accuracy -within a radius of 125 meters, 67 percent of the time by October 2001. There are a number of different geolocation technologies that have been proposed. These include, Assisted GPS (A-GPS), network-based technologies such as Enhanced Observed Time Difference (E-OTD), Time Difference of Arrival (TDOA), Angle of Arrival (AOA), and Cell of Origin (COO). This research focuses on network based techniques, …

Performance Tradeoff Study Of A Gps-Aided Ins For A Rocket Trajectory, Muhittin Istanbulluoglu

Theses and Dissertations

The Turkish Air Force (TuAF) has started a project to launch a satellite using only Turkish resources. Primary motivation behind this research is to assist TuAF's project by keeping up with these innovations in the navigational arena. The basic challenge in navigation system design is to decide which navigation system (or systems) and implementation techniques will be used, depending on accuracy requirements. The two primary navigation systems that will be integrated in this research are the Inertial Navigation System (INS), and the Global Positioning System (GPS). The Kalman filter algorithm is used to integrate INS and GPS. The rocket (Atlas …

Measurements Of Neutron Induced Surface And Bulk Defects In 4h Silicon Carbide, Kent T. Jones

Theses and Dissertations

Epitaxial n-type 4H-silicon carbide (SiC) is irradiated with 2 MeV protons to evaluate the dislocation damage effects on the optical and electrical characteristics of the material. The optical properties of the material are investigated using temperature-dependant photoluminescence (PL) and the effects of proton irradiation on the electrical properties are evaluated using current-voltage measurements and constant-voltage deep level transient spectroscopy (CV-DLTS). Subsequent high-temperature thermal annealing and recovery of the irradiated material is investigated over the temperature range of 900-1500°C. Proton-induced irradiation damage is apparent in the 4H-SiC material, affecting both the optical and electrical characteristics of the devices. The radiative behavior …

Third Quarter Report, Covering January Through March 2002, John Farley

Transmutation Sciences Materials (TRP)

Progress from June 2001-November 2001 was presented at the winter meeting of the American Nuclear Society in Reno (November 12-15, 2001), and incorporated into a refereed conference proceeding. A copy of the refereed conference proceeding has been provided to Tony Hechanova. In brief, the paper described the new program to examine the corrosive effects of lead-bismuth eutectic (LBE) on steels. We employed various types of surface studies (Scanning Electron Microscope [SEM], and X-ray Photoelectron Spectrometry [XPS]) to examine steel samples that had been exposed to LBE for various lengths of time at various temperatures. The goal is to understand the …

Computational Aerodynamic Analysis Of The Flow Field About A Hypervelocity Test Sled, Andrew J. Lofthouse

Theses and Dissertations

The flow field about the nose section of a hypervelocity test sled is computed using computational fluid dynamics. The numerical model of the test sled corresponds to the Nike O/U narrow gage sled used in the upgrade program at the High Speed Test Track facility, Holloman Air Force Base, New Mexico. The high temperatures and pressures resulting from the aerodynamic heating and loading affect the sled structure and the performance of the vehicle. The sled transitions from an air environment to a helium environment at a speed of approximately 3,300 feet per second (Mach 3 in air, Mach 1.02 in …

Alternative Pulse Detonation Engine Ignition System Investigation Through Detonation Splitting, August J. Rolling

Theses and Dissertations

A Pulse Detonation Engine (PDE) combusts fuel air mixtures through a form of combustion: detonation. Recent PDE research has focused on designing working subsystems. This investigation continued this trend by examining ignition system alternatives. Existing designs required spark plugs in each separate thrust tube to ignite premixed reactants. A single thrust tube could require the spark plug to fire hundreds of times per second for long durations. The goal was to minimize hardware and increase reliability by limiting the number of ignition sources. This research used a continuously propagating detonation wave as both a thrust mechanism and an ignition system …

Suppression Of Pilot-Induced Oscillation (Pio), Donald A. Johnson

Theses and Dissertations

Closed loop instability caused by excess phase lag induced by actuator rate limiting has been suspected in many pilot-induced oscillations (PIOs) and oscillatory departures from controlled flight. As part of the joint AFIT/TPS program, a longitudinal pilot command notch filter activated by a real-time oscillation verifier (ROVER) algorithm was developed to eliminate the PIO source for any developing, severe PIO. Closed loop computer simulations were conducted to prepare for the flight test. The HAVE ROVER flight test project was flown using the NF-16D Variable Stability In-flight Simulator Test Aircraft (VISTA). A programmable heads-up display (HUD) was used to generate a …

The Combined Effects Of Freestream Turbulence, Pressure Gradients, And Surface Roughness On Turbine Aerodynamics, Christine P. Ellering

Theses and Dissertations

This work used scaled facsimiles of real turbine blade surfaces to characterize correlations between turbine blade roughness, freestream turbulence, pressure gradients and skin friction (Cf). Addition of roughness caused Cf to increase: up to 300% for the roughest surface. Addition of freestream turbulence resulted in 125% increase for the same surface. The combined effects showed increases up to 380%. Although decreasing roughness, freestream turbulence, and Reynolds number resulted in less dramatic results, it was concluded that the Cf increases due to combined effects were consistently higher than their corresponding sum of the parts. The combined effects of roughness and pressure …

Examination Of Contact Width On Fretting Fatigue, Russell S. Magaziner

Theses and Dissertations

The primary goal of this study was to find the effects on the fretting fatigue life when systematically holding the fretting fatigue variables, peak contact pressure, maximum/minimum nominal bulk stress, and the ratio of shear traction to pressure force constant while varying the contact semi-width through changes in pad radius and normal load. Experimental tests were performed on a test setup capable of independent pad displacement. Analytical and finite element simulations of the different experimental tests were performed. The local mechanistic parameters were inspected. Five different critical plane based fatigue predictive parameters lacked effectiveness in predicting changes in life with …