Engineering Commons^™

A Shock Tube Study Of Aerodynamic Heating Of Gaps In A Cylinder Subjected To Supersonic Cross Flow, Douglas D. High

Theses and Dissertations

The effects of localized aerodynamic heating in cylinder expansion gaps positioned in cross flow were investigated in a shock tube. For this study, Mach number and Reynolds number were varied from 1.04 to 1.38 and 5 x 105 to 9 x 105, respectively. The cylinder was instrumented with quick response time thermocouples positioned on the surface of the cylinder, the wall of the gap, and the gap floor. Gap aspect ratios varied from 1.23 to 3.69. Pressure gauges were used to measure wave shock speeds, pressure ratios, and transient pressure conditions. Surface temperatures were measured and converted to heat fluxes …

Resonance Capture In Unbalanced Dual-Spin Spacecraft, Raymond Tsui

Theses and Dissertations

This study examines the spinup dynamics of dual-spin spacecraft having an imbalanced rotor. Of particular interest is a phenomenon called 'resonance capture' during which the spinup motor torque induces uncontrolled growth of nutation. A captured spacecraft tumbles end-over-end, while an escaped spacecraft experiences little nutation growth. The conditions which lead to both state are analyzed. A set of criteria based on the spacecraft's kinetic energy at the of spinup is used to determine whether or not it has been captured. To calculate the final energies against which these criteria are compared, a set of nondimensional equations of motion are numerically …

Direct Reduced Order Mixed H2/H∞ Control For The Short Take-Off And Landing-Maneuver Technology Demonstrator (Stol-Mtd), William C. Reigelsperger Jr.

Theses and Dissertations

One of the conclusions from the STOL/MTD program was the need for a multivariable method of designing controllers of low order. This research investigated that problem by studying reduced order mixed H₂/H_∞ control theory applied to the STOL Landing configuration which employs both thrust vectoring and the use of a canard. Model matching techniques were used to obtain responses that met handling qualities criteria and reduced pilot workload by decoupling pitch rate and velocity commands. The time responses were found through nonlinear simulation and showed that the full order designs did match the ideal models very well …

A Handling Qualities Investigation Of Conventional, Rate Command- Attitude Hold, And Attitude Command-Attitude Hold Response-Types In The Probe And Drogue Air Refueling Task, Michael J. Taschner

Theses and Dissertations

This investigation examines the suitability of conventional, rate command/attitude hold (RCAH), and attitude command attitude hold (ACAH) response-types for the probe and drogue air refueling task. Data from a 1974 Calspan handling qualities investigation involving conventional response-types in the probe and drogue air refueling task were analyzed using the Bandwidth and STI Dropback criterions. Flight control laws were developed to achieve twelve superaugmented and two conventional configurations. The NT-33A analog variable stability system was used to simulate a relaxed static stability fighter and the NT-33A programmable digital flight control computer simulated the desired response-types. The handling qualities of the fourteen …

Engineered Vs. Traditional: A Comparison Of Wood Beams, Richard Humphrey

Honors Capstone Projects and Theses

No abstract provided.

Reaction Kinetics Analyses Of Amine-Cured Epoxies: First Shell Substitution Effects, Hossein Noureddini, C Q. Zhang, Delmar C. Timm

Papers in Reaction Kinetics

Kinetic reaction theory was used to model first shell substitution effects for several amine-cured epoxy resins, subject to the constraint of intermolecular reactions. Moment analysis will allow numerical simulations to be extended beyond the gel point. Functionalities for several chemical moieties were correlated as a function of conversion. Simulations also incorporated population density distribution dynamics. Analyses of several oligomers clearly demonstrated the dependency of oligomeric weight fractions on first shell substitution effects and conversion. The ratio of rate constants for reactions of secondary amino hydrogens relative to reactions of primary amino hydrogens ranged from 0.5 to 1.2 for the resins …

Follow-Up Inspection Of Premature Cracking On The National Turnpike, Jefferson County, L. John Fleckenstein, David L. Allen

Kentucky Transportation Center Research Report

This report discusses the investigation of the premature cracking that has been occurring on the National Turnpike, Jefferson County since 1989. A report was issued in 1990, KTC-90-5. This report documents performance to date. A detailed distress survey was performed evaluating each slab throughout the project site.

The distress survey indicates that substantial pavement cracking has occurred since the last visual inspection in 1990.

An intense maintenance program is recommended.

Bs News

Building Services Engineering

No abstract provided.

An Analysis Of The Effects Of Modeling Brigade Templates In Camex, Douglas A. Hersh

Theses and Dissertations

This thesis effort modeled brigade-sized templates within the CAMEX model, and determined the effects of those templates on the direct fire attrition methodology. The model simulated combat between a U.S. brigade from a mechanized or armored division and a Soviet-style motorized rifle regiment. Three different scenarios were used to simulate combat between the forces. The scenarios included a movement to contact, an attack, and a deliberate defense. Each scenario was run using the battalion-sized templates and again with the brigade-sized templates. The results revealed that use of the model with brigade-sized templates will demonstrate similar results to those obtained using …

The Prediction Of Pilot Opinion Ratings Using Optimal And Sub-Optimal Pilot Models, Craig R. Edkins

Theses and Dissertations

This study details the development of a sub-optimal pilot model that blended the classical and optimal pilot model approaches in an attempt to achieve the advantages of each. This model used a numerical solution to the linear quadratic Gaussian problem to find the pilot gain, lead, and lag values that minimized a performance index consisting of task error and control usage. This development was conducted in four phases. First, an optimal pilot model developed by Systems Technology, Incorporated, was analyzed in detail. This analysis included a step-by-step example problem to clarify the model's logic and an in-depth sensitivity analysis of …

Apparatus And Method Of High-Pressure Waterjet Assisted Cooling/Lubrication In Machining, Radovan Kovacevic

Mechanical Engineering Faculty Patents

An apparatus for high-pressure waterjet assisted machining includes a drive motor, spindle and rotary cutting tool with cutting inserts. The apparatus further includes a high-pressure intensifier pump providing cutting fluid at a pressure greater than 50,000 psi. A cutting fluid conduit system in the rotary cutting tool includes a main flow channel, a distribution manifold, a plurality of radially extending feed channels and a plurality of cooperating nozzles for delivering fluid behind the cutting inserts. The cutting fluid then passes through one or more apertures in the inserts into an interface defined by the inserts of the cutting tool and …

Morphological Composite Materials Formed From Different Precursors, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A method of producing a multiphase polymer is disclosed whereby the phases have the same chemical structure but have different morphological states and thus different properties. This is achieved by forming a mixture of precursors of the polymer, at least one of the precursors having a reaction rate higher than the other precursor or precursors in the mixture. The precursor having the highest reaction rate is then converted to obtain a composite of a polymer and the precursors that are not polymerized. This mixture might also be formed by mixing a soluble polymer with its precursor. The polymer/precursor composite is …

Draft Of Articles Of Incorporation For Friends Of The Tractor Test Museum, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

No abstract provided.

Pc Software For Optimizing Groundwater Contaminant Plume Capture And Containment, Richard C. Peralta, Herminio H. Suguino, Alaa H. Aly

Civil and Environmental Engineering Faculty Publications

Simulation/optimization (S/0) models can be used to speed the process of computing desirable groundwater pumping strategies for plume management. They make the process of computing optimal strategies fairly straightforward and can help minimize the labor and cost of groundwater contaminant cleanup.

Laser Resonators Using Tiered Fresnel Mirrors, Bruce Dale Ulrich

Dissertations and Theses

A reflective Tiered Fresnel Zone Plate, herein called a Tiered Fresnel Mirror TFM, with a focal length on the order of a meter is studied for use as the mirror(s) in a Fabry-Perot interferometer type of laser. The relative phase transition within the individual zones (ideally smooth from zero to pi) is stair-stepped or tiered in the longitudinal direction of the mirror. Within an individual zone the step height is constrained to a constant whereas the width of the tiers are monotonically decreased when traversing radially outward so that the overall profile follows the ideal smooth curve. The effectiveness of …

Ultrafast Dynamics In Field-Enhanced Saturate Absorbers, J. R. Karin, R. J. Helkey, Dennis J. Derickson, R. Nagarajan, D. S. Allin, J. E. Bowers, R. L. Thornton

Electrical Engineering

Absorption recovery dynamics of GaAs/AlGaAs field-enhanced waveguide saturable absorbers are studied by pump-probe differential transmission measurements. We compare the response of bulk and single quantum well absorbers at different reverse bias levels and pump powers, and find an ultrafast transient in the response, followed by a slower rise before the final recovery. The absorption fully recovers after a few picoseconds, which is an important result for mode-locked lasers.

Museum Committee Meeting February 1994, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Master's student Tour of Museum

Ccfss Technical Bulletin February 1994, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 10, Number 2, February 1994, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Acuta Enews February 1994, Vol. 23, No. 2

ACUTA Newsletters

In This Issue

Board report

Presidents message

What's right...what's wrong? States to develop telecommunications modernization plans

21st century technology

A Finite Capacity Queue With Markovian Arrivals And Two Servers With Group Services, Srinivas Chakravarthy, Attahiru S. Alfa

Industrial & Manufacturing Engineering Publications

In this paper we consider a finite capacity queuing system in which arrivals are governed by a Markovian arrival process. The system is attended by two exponential servers, who offer services in groups of varying sizes. The service rates may depend on the number of customers in service. Using Markov theory, we study this finite capacity queuing model in detail by obtaining numerically stable expressions for (a) the steady-state queue length densities at arrivals and at arbitrary time points; (b) the Laplace-Stieltjes transform of the stationary waiting time distribution of an admitted customer at points of arrivals. The stationary waiting …

Minutes Friends Of Tractor Test Museum Feb. 1994, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Articles of Incorporation Museum Inventory Roof Protection

Capacity Of Automated Highway Systems: Effect Of Platooning And Barriers, H.-S. Jacob Tsao, Randolph Hall, Bruce Hongola

Faculty Publications

The concept of Automated Highway Systems (AHS) is based on the belief that an appropriate integration of control and communication technologies placed on the vehicle and on the highway can lead to a large improvement in capacity and safety without requiring a significant amount of additional highway right-of-way. Stemming from this belief are various conceptual scenarios for vehicle/highway automation.An AHS consists of two major components: vehicle/highway automation technology and highway operating strategy. In this paper, we study the capacity of key AHS operating scenarios.

Classification Using Set-Valued Kalman Filtering And Levi's Decision Theory, T.K. Moon, Scott E. Budge

Electrical and Computer Engineering Faculty Publications

We consider the problem of using Levi's expected epistemic decision theory for classification when the hypotheses are of different informational values, conditioned on convex sets obtained from a set-valued Kalman filter. The background of epistemic utility decision theory with convex probabilities is outlined and a brief introduction to set-valued estimation is given. The decision theory is applied to a classifier in a multiple-target tracking scenario. A new probability density, appropriate for classification using the ratio of intensities, is introduced.

Epistemic Decision Theory Applied To Multiple-Target Tracking, T. K. Moon, Scott E. Budge, W. C. Stirling, J. B. Thompson

Electrical and Computer Engineering Faculty Publications

A decision philosophy that seeks the avoidance of error by trading off belief of truth and value of information is applied to the problem of recognizing tracks from multiple targets (MTT). A successful MTT methodology should be robust in that its performance degrades gracefully as the conditions of the collection become less favorable to optimal operation. By stressing the avoidance, rather than the explicit minimization, of error, the authors obtain a decision rule for trajectory-data association that does not require the resolution of all conflicting hypotheses when the database does not contain sufficient information to do so reliably. This rule, …

Formation Of Plasma Polymer Thin Films Containing Reactive Metal Chelate Sites, J. M. Skelly, Nicholas C. Morosoff, V. T. Stannett, A. L. Crumbliss

Chemical and Biochemical Engineering Faculty Research & Creative Works

We report here the successful incorporation of chemically active Co2+ and Ni2+ centers into plasma polymer thin films. Metal center incorporation was accomplished by simultaneous plasma polymerization of sublimed Co2+ or Ni2+ complexes with gaseous "comonomers" or Ar. The metal complexes include N,N′-bis(salicylidene)-1,2-phenylenediaminecobalt(II) (CoSalophen), N,N′-bis(salicylidene)ethylenediaminecobalt(II) (CoSalen), N,N′-bis(3-fluorosalicylidene)ethylenediaminecobalt(II) (CoFluomine), meso-tetraphenylporphyrinatocobalt(II) (CoTPP), meso-tetraphenylporphine (TPP), and meso-tetraphenylporphyrinatonickel(II) (NiTPP). Modification to the metal complex structure was observed by IR and UV-vis spectroscopies. IR spectra of plasma polymer films containing the Schiff's base complexes, prepared using Ar as a carrier gas, contained a band at 2190 cm−1, which can be attributed to nitrile group formation, …

Epistemic Decision Theory Applied To Multiple-Target Tracking, Wynn C. Stirling, T. K. Moon, S. E. Budge, J. B. Thompson

Faculty Publications

A decision philosophy that seeks the avoidance of error by trading off belief of truth and value of information is applied to the problem of recognizing tracks from multiple targets (MTT). A successful MTT methodology should be robust in that its performance degrades gracefully as the conditions of the collection become less favorable to optimal operation. By stressing the avoidance, rather than the explicit minimization, of error, the authors obtain a decision rule for trajectory-data association that does not require the resolution of all conflicting hypotheses when the database does not contain sufficient information to do so reliably. This rule, …

Electromagnetic Characteristics Of Superquadric Wire Loop Antennas, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

The analysis of antenna configurations in the form of a generalized superquadric loop, which includes circular, elliptical and rectangular loop geometries, is presented in this paper. Use of a Galerkin form of the moment method with piecewise sinusoidal subsectional basis and testing functions provides rapid numerical convergence and accurate representation of the antenna current. A convenient parametric representation for the superquadric curve is developed to allow a subsectional formulation using curved wire segments, rather than the commonly employed piecewise linear segments, to construct the geometry. Both magnetic frill and delta gap source models are implemented to allow a detailed study …

Inhomogeneous Anisotropic Percolation: Two-Dimensional Numerical Threshold Analysis, Yuris A. Dzenis, S. P. Joshi

Department of Engineering Mechanics: Faculty Publications

Monte Carlo simulations of percolation on a square lattice with anisotropic inhomogeneous probability distribution are reported. Finite-size scaling is used for data analysis. As inhomogeneity increases, the critical probability decreases; whereas the correlation-length exponent remains, within computation errors, the same as in classical two-dimensional percolation.

Barge Impact Loads For The Maysville Bridge, Michael W. Whitney, Issam E. Harik, James J. Griffin, David L. Allen

Kentucky Transportation Center Research Report

This report provides the barge equivalent static load distribution data needed to apply method II of vessel impact design for the Maysville, Kentucky bridge over the Ohio River. The information provided in this report is in accordance with the AASHTO Guide Specification and Commentary for Vessel Collision Design of Highway Bridges.

A computer program was written to process the database and calculate the probability based length, width., and capacity for each barge category. Additionally, a second computer program was written to calculate the probability based number of barges in a flotilla column and row, and subsequently categorize that flotilla based …