Engineering Commons^™

Delay Performance Of Cebus And Modified Cebus Schemes, Altaf Hussain

Theses

In this thesis the performance of the CEBUS (Consumer Electronics Bus), a local area network proposed by the Electronics Industries Association for the 'Smart House,' is analyzed under varying network load and traffic patterns that would occur in a typical home environment. Reduced complexity versions of the CEBUS scheme are compared with the standard CEBUS scheme.

It was found from simulation analysis that the delay in the CEBUS network, at a given network bandwidth, is dependent upon the message priority and the traffic pattern in the network. It was also observed that the performance of a modified CEBUS scheme was …

Disc Size Scale-Up In Rotating Biological Contactor System, Chi-Sheng Chang

Theses

Disc size scale-up of prototype and small-scale RBC plants are successfully developed by applying the 114 data sets obtained from 12 RBC plants to the evaluation of percent sBOD remaining. These data analyses are performed by the least square method, therefore, the scale-up factors of the prototype and the small-scale are determined at different hydraulic loading. Furthermore, the relationship between scale-up factor and the disc diameter are established under the given flow rate, the number of stages, and the number of discs. A group of Curves are obtained and can be utilized for the full-scale RBC plant preliminary design. The …

Instrumentation And Control For A Microprocessor-Based Coronary Perfusion System, Daniel L. Priester

Master's Theses (1922-2009) Access restricted to Marquette Campus

No abstract provided.

Study Of Cathodoluminescence In Semiconductors, Mandakini V. Kale

Electrical & Computer Engineering Theses & Dissertations

Cathodoluminescence in Zn doped GaAs and ZnSe, the materials of interest for electron-beam controlled semiconductor switches, has been investigated. A new diagnostic technique, using telescopic setup of lenses, was developed to study the spatially resolved cathodoluminescence. The setup eliminated the light, other than rays from the sample, parallel to the optical axis, resulting in an enhanced spatial resolution. At high e-beam energies, light was detected, from the Zn layer region in the GaAs. It is proposed to be due to the radiative recombination of electron-hole pairs, created by the e-beam. For the polycrystalline ZnSe no light emission was detected. This …

Finite Element Frequency Domain Solution Of Nonlinear Panel Flutter With Temperature Effects And Fatigue Life Analysis, David Yongxiang Xue

Mechanical & Aerospace Engineering Theses & Dissertations

A frequency domain solution method for nonlinear panel flutter with thermal effects using a consistent finite element formulation has been developed. The von Karman nonlinear strain-displacement relation is used to account for large deflections, the quasi-steady first-order piston theory is employed for aerodynamic loading and the quasi-steady thermal stress theory is applied for the thermal stresses with a given change of the temperature distribution, ΔΤ (x, y, z). The equation of motion under a combined thermal-aerodynamic loading can be mathematically separated into two equations and then solved in sequence: (1) thermal-aerodynamic postbuckling and (2) limit-cycle oscillation. The Newton-Raphson iteration technique …

An Experimental Investigation Of Composite Sensors For Crack Length Measurement, Manickam Ramasamy

Mechanical & Aerospace Engineering Theses & Dissertations

Structural defects such as cracks can cause catastrophic failure in engineering components or structures. There are many techniques to measure the crack growth in materials and are commercially available. In this thesis, bondable crack length measurement gages have been investigated and these gages give electrical signal as the output and measure the crack length continuously. Silver paint, nickel powder impregnated epoxy and carbon powder impregnated polymer composite gages are investigated and tests are conducted by resistance measurement method with simple instrumentation and by potential drop method with a constant current output source. Rectangular shape gages have been investigated and as …

Experimental Study Of Transition In A Supersonic Free Shear Layer, Rudolph A. King

Mechanical & Aerospace Engineering Theses & Dissertations

The transition behavior of a free shear layer above a cavity with high and low levels of freestream acoustic disturbances has been investigated at Mach 3.5 in the Supersonic Low-Disturbance Pilot Tunnel located at NASA Langley Research Center. Schlieren photography, mean pitot pressure data, and hot-wire surveys were used to detect transition locations. The transition Reynolds numbers obtained were between Re_Tr = 3.6 x 10⁵ and 5.3 x 10⁵ in good agreement with conventional ("noisy") wind tunnel results. The study indicated that the effects of a decrease in freestream noise on Re_Tr were minimal but, as …

Linearized Dynamics Of Space Structures With Articulated Appendages, Gopichand Koganti

Mechanical & Aerospace Engineering Theses & Dissertations

The inherent difficulties of the conventional spacecraft design, which first considered the optimization with respect to structural variables and then with respect to control variables, have led to the concept of Controls-Structures Interactive Design. The success of the CSI design of Space structures without articulated appendages has prompted the extension of the CSI design to systems with articulated appendages. The presentation is of two parts, the first part deals with the derivations of the equations of motion and the second part deals with the eigenvalue/vector approximations.

Three approaches, namely: the multibody approach, the finite element based approach with hinge joints …

Thermal Characterization Of Carbon Monoxide Oxidation Catalysts Using Thermogravimetric Analysts And Differential Scanning Calorimetry, Rene A. Bartgis

Chemistry & Biochemistry Theses & Dissertations

Catalysts composed of platinum and/or palladium on tin (IV) oxide supports, with and without silica gel, as well as catalysts composed of gold on manganese oxide, have been developed for the recombination of carbon monoxide and oxygen to form carbon dioxide for use in carbon dioxide lasers. A thermogravimetric method and a differential scanning calorimetric method have been developed for the thermal characterization of these catalysts. The mass loss data and the enthalpy changes determined as the catalysts lost water were then related to existing activity data for these catalysts. No relationship was found between the thermal data and the …

Domain Limitations And Interface Requirements For Expert Developed Knowledge Based Systems, Bernard Lee Lewis

Engineering Management & Systems Engineering Theses & Dissertations

The expanded use of graphical, case-based and object oriented techniques in expert systems creation has made it more practical for domain experts to develop their own applications. This thesis focuses on the elements necessary in an expert/developer interface and looks at various forms and techniques that exemplify such an approach. The spreadsheet metaphor is used for an interface or managed set of interfaces that a domain expert can use in building his own expert system or prototype. criteria are established for such interfaces and recent commercial offerings that make expert-created knowledge-bases more practical are reviewed for techniques that qualify. Approaches …

Deconvolution Applications In Arterial Dynamics, Shanthi Ganesan

Theses

This thesis deals with the computation of the Arterial Impulse Response Function by deconvolving aortic pressure and flow signals in time domain. Several methods have been developed in the past to obtain a solution for the convolution integral. These are (1) Transform method, and (2) Numerical Approximation methods : a. Conventional method b. Relaxation methods.

These methods have been applied in the past to the RC network model and it was found to work well. In this thesis, the methods are applied to data from more realistic models and also on data obtained from dogs. The model considered is a …

Radiation From The Cylindrical Dielectric Taper, Tor-Odd Hoydal

Theses

The radiation problem of the cylindrical dielectric taper, excited by the HE₁₁ dominant mode, is studied. A theoretical model and a numerical investigation into the radiation characteristics of such a tapered structure are presented. The model is based upon the combination of the exact modal field solutions for a step profile cylindrical dielectric waveguide, Local Mode Theory, and the Equivalence Principle for the determination of equivalent current densities.

The far-zone radiation field is considered to be the summation of the fields produced by two radiative components in the dielectric rod/conical structure: The "aperture" of the uniform dielectric rod at …

Stability Of Hot Mix Asphalt With Petroleum Contaminated Soils, De-Rong Lobo Huang

Theses

One of the most effective ways of reducing petroleum contaminated soil is to use it in the production of hot mix asphalt. Both asphalt cement and petroleum contaminates have similar chemical properties. Therefore, The contaminates will be locked within the asphalt matrix without potential leaching.

The six different petroleum contaminate soil samples from New Jersey were used in this research. Since those samples have different physical properties (such as moisture content, specific gravity, plastic limit, liquid limit, grain size distribution) and chemical properties( such as concentration of the contaminate, and type of contaminates) the maximum amount of petroleum contaminated soil …

Bio-Mechanics Of The Hip Joint And The Engineering Considerations In The Treatment Of Unstable Intertrochanteric Fractures, Manoj D. Nene

Theses

Numerous previous attempts have been made to determine the magnitude and the direction of forces acting on the hip joint. The mechanism of femoral neck fractures and the frequently occurring failure of its internal fixation has led engineers to analyze the forces involved. An unstable intertrochanteric fracture is one which lacks continuity of the bone cortex on the opposing surfaces of the proximal and digital fragments. A mathematical model is created in this study to examine the 135° and 150° nail plate. The results give an approximate estimation of stresses on the two plates. A 3D finite element model of …

Knowledge Based Designing Of Broadband Coaxial Cable Networks, Tauqir Hameed

Theses

The objective of this research was to build a broadband coaxial cable network. One of the basic requirement of a network is the physical link transmission medium. For the purposes of this research, broadband coaxial cable was chosen as a physical medium of data communication. The approach taken in this research was to divide network design into three main steps. In the first step, the decision on topology of the network was determined. Both Star and Minimum Spanning Tree topologies were used and then the Esau-Williams Algorithm was employed to minimize the cable length. In the second step, various signal …

An Analysis Of Base Level Environmental Organizations, John F. Akers Jr.

Theses and Dissertations

The purpose of this thesis was to try and determine if there was one type of environmental organization which was truly so much more effective than the others that all bases should have it, or if the decision of which type of environmental organization to have should be left entirely to the bases. In addition, I hoped to discover the advantages and disadvantages of each type of organizational structure. I feel that knowing these advantages and disadvantages will greatly aid those individuals making the decisions on environmental organizational structure. In completing this study I turned to the only place the …

An Evaluation Of The Implementation Of Two-Levels Of Maintenance At Strategic Air Command Intercontinental Ballistic Missile Bases, Alan H. Russell

Theses and Dissertations

As a result of the 1979 Defense Management Review, Headquarters, Strategic Air Command has initiated programs of alternative levels of maintenance in order to trim excess costs. This study investigates the suitability of the SAC program which changed selected base-level strategic missile maintenance tasks from three to two-levels of maintenance. Using an opinion oriented questionnaire, this research surveyed a sample of missile maintenance personnel on their perceptions of the SAC program which implemented an alternative to intermediate-level maintenance. Analysis of survey results show respondents tended to believe the SAC program has not added benefit to their mission effectiveness. Other studies …

Life Cycle Costs Of The C-130 Electrical Power System Upgrade, Theodore D. Seymour

Theses and Dissertations

This research investigated the life cycle costs of three alternative electrical power systems for a planned electrical system upgrade to the C-130 transport aircraft. Research identified the contractors as (1) Sundstrand, (2) Westinghouse, and (3) Leland. The literature review included discussions on the C-130, electrical power systems and the proposed alternatives, and the elements of life cycle cost analysis. In the discussion on supportability issues, this research evaluated changes in mission capable rates and the needed fleet size to perform the current mission. In estimating Operating and Support costs, this research used the analogy approach. Analogies were based on expert …

An Investigation Of Project Management Techniques For Scheduling Raaf Depot Level Maintenance, Kerry M. Bayley

Theses and Dissertations

This research investigates scheduling performances of commercial project management software. It is based on difficulties that the Royal Australian Air Force experienced in evaluating microcomputer-based packages in maintenance task scheduling of aircraft undergoing Depot Level Maintenance. A literature review found only one paper quantifying commercial software performances. No standard performance metrics or test data were found. Several packages were evaluated using a common set of 110 single-project resource- constrained networks. The performance measure used was closeness to optimally minimum Total Durations. No package performed best on all problems. On average, the best produced schedules 5.2% longer than optimal, with 95 …

An Analysis Of Measures Used To Evaluate The Air Force Critical Item Program, Robert R. Lee

Theses and Dissertations

The purpose of this study was to evaluate the potential of two measures, percent defects and cycle time, to measure the overall performance of the Air Force Critical Item Program (CIP). The need for such study was generated from the current absence of any measurement system available to evaluate the CIP. This research used these two measures with actual data, evaluated the correlation between aircraft availability and percent defects and cycle time, and analyzed management perceptions addressing the usefulness of these measures for field use. Performance of this analysis resulted in support for these measures by over two thirds of …

Impacts Of Biomonitoring Requirements On Dod Wastewater Treatment Facilities, James R. Brady

Theses and Dissertations

Legislative emphasis on reducing the toxicity of wastewater effluent has resulted in increasingly sophisticated methods of determining toxicity. The purpose of this research project is to assess the impacts on DoD wastewater treatment facilities of one new monitoring method, biomonitoring. Biomonitoring has impacted DoD wastewater treatment facilities, however not to the degree anticipated. For bases that have been impacted, cost of contracting the tests is the primary problem associated with biomonitoring. Many bases have not been impacted because wastewater reuse has negated the need for discharge permits, and the inherent monitoring requirements. Bases subject to biomonitoring should assess water reuse …

A Microcomputer Program For Estimating Production Costs Of Injection Molded Plastic Structures, Kyle F. Byard

Theses and Dissertations

The job of estimating the production costs of injection molded thermoplastic structures requires designers and analysts to produce detailed preliminary drawings and consult machinists with expertise in mold production. Interviews with injection molding experts produced a scale of part complexity and associated range of labor hours for mold production. This scale is incorporated into a cost estimating methodology which allows the analyst to estimate the cost of the structure without the aid of technicians. The resulting cost model for the injection molding process is then programmed into an interactive Pascal computer program for ease of use and documentation.

An Investigation Of The Air Force Risk Model, Thomas R. O'Hara

Theses and Dissertations

This study develops a dependent component cost risk model validation methodology and applies it to the Air Force Risk Model. The validation process consists of ensuring that logically consistent input parameters are acted on properly by the cost risk methodology. users of all dependent component risk models must be concerned with logically consistent input parameters. Two criteria define logical consistency. The first is the correlation matrix consistency and the second is the consistency between pairs of cost distributions. Three validation criteria are defined and used to validate a cost risk model. The first criterion is that the process must maintain …

A Model For Estimating Aircraft Recoverable Spares Annual Costs, Phillip L. Redding

Theses and Dissertations

This thesis covers three objectives: (1) develop a background reference document concerning recoverable spares cost estimating; (2) evaluate a representative sample of existing spares cost models; and (3) use aircraft physical and performance characteristics to develop a model for estimating annual replenishment spares cost. A condemnations cost estimating relationship (CER) was developed first and then both a CER and spreadsheet generated factors which related condemnations to replenishment spares costs were developed. For the condemnations CER, only logarithmic transformations provided statistically acceptable results, and even these models exhibited wide prediction intervals due to large amount of variability in the CER databases …

A Guide For The Consideration Of Composite Material Impacts On Airframe Costs, Jeffrey L. Isom

Theses and Dissertations

This study provides a guide to cost analysts who must consider the impact of composite materials on airframe costs. A literature review was conducted to determine the availability of cost models which incorporate the effect of composites on cost. A number of models are available, but no individual model was found that is applicable for every situation. In order to provide a baseline upon which analysts can compare model results as well as provide guidance in selecting cost drivers, a Delphi survey was conducted. Questionnaire results indicate that composite weight (as a percentage of total weight), composite part complexity, percentage …

Education Necessary For Air Force Software Managers To Use The Ada Programming Language And Software Engineering Effectively, James W. Worley Jr.

Theses and Dissertations

This research investigated the perceived Ada and software engineering education needs of software managers throughout the Air Force and provided recommendations to Air Staff for developing the education. Since the Department of Defense mandated all DOD agencies use the Ada programming language for software development, the education of the personnel who have to support the policy has lagged behind the implementation Ada is not a simple language to use and is only fully effective if used with sound software engineering principles. A survey was given to Air Force mid-level personnel who manage software in some capacity. Of the software personnel …

Inaccurate Data Entry Into The Air Force Maintenance Data Collection System, Jon R. Determan

Theses and Dissertations

This research investigated the data collection environment under the Core Automated Maintenance System (CAMS), a computerized information system used in the Air Force's aircraft maintenance complexes. The research measured maintenance personnel's perception of the nature, extent, and causes of data inaccuracies occurring in the CAMS data collection environment. The nature was differentiated as being either intentional or accidental. Maintenance personnel felt that difficulty in entering information into CAMS accounted for the largest percentage of intentional errors and that insufficient training on CAMS accounted for the largest percentage of accidental errors. A comparison of this research to the results of earlier …

An Exploratory Application Of Neural Networks To The Sortie Generation Forecasting Problem, James M. Dagg

Theses and Dissertations

This exploratory study assesses the accuracy of backpropagation neural networks in predicting sortie generations, given pre-specified levels of air base resources. Single hidden layer networks and two-way interaction regression metamodels were fitted to simulated data previously generated by way of a factional design for ten factors at two levels, and subsequently tested (cross-validated) via an independent testing sample. It was determined that regression metamodels were generally superior in predicting unseen cases, while their network counterparts exhibited far better goodness-of-fit characteristics. The research consistently emphasizes that goodness-of-fit in no way necessarily implies goodness-of-prediction, in that different non-equivalent statistical measures are required …

An Evaluation Of Logistics Support For F-16 Aircraft Owned By Foreign Countries, Paul J. Lyons

Theses and Dissertations

The purpose of this thesis was to examine the logistics support provided by the United States Air Force (USAF) for F-16 aircraft owned by foreign countries. The research drew from historical trends and personal experiences to examine the ability of the U.S. to provide logistics support for F-16 aircraft owned by U.S. allies. The study found that timely, efficient support of FMS customers possessing F-16 aircraft does not appear to be a principal concern of the USAF logistics system. Complexity of processes, untimely responses, and failure to consider customer needs are common failings on the part of the USAF.

Analysis Of Department Of Defense Organic Depot Maintenance Capacity Management And Facility Utilization Factors, Marlies Dewoody

Theses and Dissertations

This study investigated the effects of mandated depot capacity utilization rates on throughput, inventory, and operating expense. The measures of merit analyzed were work in process inventories, leadtime, and throughput. Since the services do not use a common computer system to track/compute capacity data, a computer simulation provided the data used to meet the research objectives. The simulation modeled a serially interdependent system subject to statistical fluctuations. Variability in the system was reduced by reducing the spread around the processing time mean. Buffer inventories were placed in front of each process to protect the process from variability. Constrained systems were …