Engineering Commons^™

Droplet Evaporation And Deformations In An Amplitude Modulated Ultrasonic Field, Nihad E. Daidzic, Rene Stadler, Adrian Melling

Aviation Department Publications

The aim of the report presented is the measurements of droplet oscillations.

Geometric Stiffness Effects On Data Recovery Of An Idealized Mast/Blanket Model, Paul A. Bosela, D. R. Ludwiczak

Civil and Environmental Engineering Faculty Publications

The photovoltaic arrays for the international space station consist of a pre-tensioned blanket of solar collectors and a deployable mast. NASA uses the MSC/NASTRAN finite element program for modeling the dynamic response of the structure due to various loading conditions, such as plume impingement during shuttle docking. This finite element program uses the updated stiffness matrix (elastic plus geometric, or initial stress stiffness matrix) in determining the natural frequencies and mode shapes, as well as the dynamic response, of a pre-loaded structure. However, during the data recovery phase, when the moment and shear at the supports, and internal stresses are …

Grain-Boundary Structure Effects On Intergranular Stress Corrosion Cracking Of Alloy X-750, Brent L. Adams, Ted Olsen, N. Panayotou, Y. Pan

Faculty Publications

This work was supported by the Department of Energy under Grant No. DE-FG02-88ER 45355. TO was supported by the National Science Foundation during her 1993-94 stay at the Institute for Advanced Studies (Princeton) under grant DMS-9304580. The authors wish to acknowledge helpful discussion with Carol Nichols, John Hack, Gino Palumbo, Karl Aust, and Gary Was. It is well known that the properties and behavior of grain boundaries are strongly affected by local chemistry and atomic structure. This paper focuses on the mesoscale description of grain boundary structure (i.e. the five crystallographic degrees of freedom) and correlations with intergranular stress corrosion …

United States Patent: System And Method For Compensating Polarization-Dependent Sensitivity Of Dispersive Optics In A Rotating Analyzer Ellipsometer System, Blaine D. Johs, Shakil A. Pittal, Steven E. Green, John A. Woollam, David W. Doerr, Reed A. Christenson

Department of Electrical and Computer Engineering: Faculty Publications

An ellipsometer system which includes a pivotal dispersive optics positioned to receive polychromatic light from an analyzer thereof, without further focusing after reflection from a substrate system, is presented. In addition, a stationary compensator, positioned between an analyzer and the dispersive optics, which serves to reduce detector element polarization dependent sensitivity to light entering thereto after it interacts with the dispersive optics, is disclosed. The use of a light fiber to carry light from a source thereof, to a polarization state generator, is also disclosed. The method of the present invention can include application of mathematical correction factors to, for …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 4, April 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Determination Of Iron Colloid Size Distribution In The Presence Of Suspended Cells: Application To Iron Deposition Onto A Biofilm Surface, Waihung Lo, Yarrow M. Nelson, Leonard W. Lion, Michael L. Shuler, William C. Ghiorse

Civil and Environmental Engineering

Transport and deposition of colloidal Fe, Mn and Al oxides play key roles in the cycling of toxic transition metals in aquatic environments because these colloids strongly bind transition metals. Further, attachment of biological cells and biofilm growth on surfaces can indirectly affect toxic metal distribution by influencing the deposition of colloidal oxides to surfaces. To elucidate the mechanisms governing these processes, deposition of colloidal oxides onto surfaces must be evaluated in the presence of suspended and adherent bacterial cells. Both particle size and concentration are expected to influence deposition. An experimental protocol was developed to determine the size distribution …

The Airline Quality Rating 1996, Brent D. Bowen, Dean Headley, Uno Aviation Institute

Faculty Books and Monographs

UNOAI Report 96-4

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline performance on combined multiple factors important to consumers. Development history and calculation details for the AQR rating system are detailed in The Airline Quality Rating issued in April, 1991, by the National Institute for Aviation Research at Wichita State University. This current report, Airline Quality Rating 1996, contains monthly Airline Quality Rating scores for 1995. Additional copies are available by contacting Wichita State University or the University of Nebraska at Omaha.

The Airline Quality Rating 1996, contains …

18th Conference On Senior Engineering Design Projects, College Of Engineering And Applied Sciences

Senior Engineering Design Conference

The 18th Conference on Senior Engineering Design Projects was held on April 9, 1996 at the College of Engineering and applied Sciences on the Parkview Campus of Western Michigan University. The college sponsors the conference to showcase the work of its graduating seniors, who are required to complete a capstone project that puts into practice what they have learned. Many of the projects are sponsored by business and industry.

Santa Clara Magazine, Volume 38 Number 2, Spring 1996, Santa Clara University

Santa Clara Magazine

10 - IT CHANGED MY LIFE Reflecting on 30 years of the Santa Clara Communiry Action Program, former SCCAP directors recount what participating in the organization meant to them.

14 - ATTICUS An excerpt from the recent novel by SCU's new Gerard Manley Hopkins, S.)., Professor in Arts and Humanities. By Ron Hansen M.A. '95

22 - LOST IN CYBERSPACE Universities debate Internet addiction among students: Should we stop them before rhey surf again? By Jeff Brazil '85

28 - THE GRAPES OF WRATH: PART II Professor of Modern Languages Francisco Jimenez '66 remembers his childhood as a migrant laborer, …

Implementation Of Alf Results To Designing Flexible Pavements In Louisiana, Ludfi Djakfar

Doctoral Dissertations

The Louisiana Transportation Research Center (LTRC) recently conducted a research effort using the Accelerated Loading Facility (ALF). The objective of the research was to evaluate a limited number of alternative base materials and construction techniques envisioned to provide a significant reduction in the occurrence of shrinkage and reflected block cracking in the cement-stabilized bases. Nine test sections were constructed for this research, using the same wearing course material but having different thicknesses of crushed stone and soil cement bases and subbases. The soil cement base is the most commonly used base material in Louisiana, whereas crushed stone is a preferred …

The Effect Of Wet End Operations On Sizing Loss In Alkaline Papers, Suresh B. Cherukuri

Masters Theses

Changes in wet end of alkaline papermaking affect the size development as well as sizing loss. These changes include pH, alkalinity and type of filler used. Precipitated and ground varieties of carbonate fillers and the alkalinity associated with · them are believed to be the causes for the gradual sizing loss in alkaline papers due the accelerated hydrolysis reaction of sizing chemicals at higher alkalinity.

Precipitated and ground calcium carbonate fillers are used as fillers and compared to non carbonate filler such as kaolin clay for their response to size development and sizing loss at lower and higher alkalinity ranges …

A Nonparametric Wet/Dry Spell Model For Resampling Daily Precipitation, Upmanu L. Lall, Balaji Rajagopalan, David G. Tarboton

Civil and Environmental Engineering Faculty Publications

A nonparametric wet/dry spell model is developed for resampling daily precipitation at a site. The model considers alternating sequences of wet and dry days in a given season of the year. All marginal, joint, and conditional probability densities of interest (e.g., dry spell length, wet spell length, precipitation amount, and wet spell length given prior to dry spell length) are estimated nonparametrically using at-site data and kernel probability density estimators. Procedures for the disaggregation of wet spell precipitation into daily precipitation and for the generation of synthetic sequences are proffered. An application of the model for generating synthetic precipitation traces …

A Comparison Of Two Geo-Centric Attitude Indicators As Aids To Unusual Attitude Recovery: Pictorial Vs. Symbolic Displays, Christopher Cohoes

Master's Theses - Daytona Beach

Aircraft require high cognitive quality aircraft attitude information. Evidence will be presented on aircrew decision-making performance on an unusual attitude recovery task using three different types of attitude displays. Results indicated that among a sample of low-flight time student pilots attending Embry-Riddle Aeronautical University, mean reaction times were significantly faster and error rates significantly lower using an outside-in pictorial display than with either an outside-in symbolic display or an attitude gyro. This is attributed to the pictorial display being a more intuitive display by providing a more natural or realistic representation of aircraft orientation than the other two displays. The …

Evaluation Of A Display With Both Quickened And Status Information For Control Of A Second Order System, Matthew J. Neal

Master's Theses - Daytona Beach

Quickened displays have a severe limitation in that they do not give any indication of status information, and therefore no indication of actual error. It was hypothesized in this study that a display with both quickened and status information would enable the operator to make more effective control responses than either a status alone display, or a quickened alone display.

A horizontal axis pursuit tracking task was developed and controlled by eighteen participants with three display types: (1) a status alone display; (2) a quickened alone display; and (3) a status and quickened combined display.

The primary hypothesis was only …

Acuta Enews April 1996, Vol. 25, No. 4

ACUTA Newsletters

In This Issue

From the President

Pasadena Community College

Port by Every Pillow at WCU

Multi-Media at Sewanee

DC at a Glance

From ACUTA Headquarters

Convection During Thermally Unstable Solidification Of Pb-Sn In A Magnetic Field, Hui Song, Surendra N. Tewari, H. C. Degroh Iii

Chemical & Biomedical Engineering Faculty Publications

Convection and macrosegregation in directionally solidified hypoeutectic Pb-38 wt pct Sn and hypereutectic Pb-64.5 wt pct Sn have been examined during upward and downward growth. Temperature fluctuations are observed along the length of the melt column during downward growth. With increasing Rayleigh number, these fluctuations change from none, to cyclic, to time periodic having multiple harmonics, and finally to random. At the higher convective driving force of 350 K temperature inversion, the transverse magnetic field decreased convective levels, strong random temperature fluctuations (flows) becoming smaller and periodic. The maximum field of 0.45 T was unable to completely eliminate convection. For …

Bulletin - Spring, 1996, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A seventeen page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.

Using An Evolutionary Strategy To Solve Frequency Allocation Problems, Min Chen

Masters Theses

Frequency allocation problem (F AP) is to assign radio frequencies to a number of stations subject to a number of constraints, so that the minimum interference is suffered. FAP is NP-complete. In order to solve FAPs, there are interference constraints to be satisfied. There are two constraints of FAP which were the focus of this study: (1) co-channel interference, (2) adjacent channel interference.

Evolutionary Strategies (ESs) are very efficient optimization algorithms based upon the principles of adaptive selection found in nature. In this study, a (μ,A)ES algorithm was implemented to solve instances of FAP.

This thesis has demonstrated that …

The Design, Fabrication, And Evaluation Of A Low-Speed, Low-Turbulence, Anechoic Wind Tunnel, Brian J. Kaplan

Master's Theses - Daytona Beach

In order to provide a means for testing noise reduction techniques in propellers and fans, a low-speed, low-turbulence, anechoic wind tunnel was designed, fabricated and evaluated at Embry-Riddle Aeronautical University.

This open circuit wind tunnel was designed using several other existing wind tunnels as a guide and incorporated an open jet test section. The tunnel, which was built almost entirely out of wood and fiberglass, is powered by a 15 hp centrifugal fan.

Tufts of yarn, a pitot-static tube, and a hot film anemoter were used to determine the flow characteristics in the test section of this wind tunnel. From …

Non-Markovian Brownian Motion In A Viscoelastic Fluid, V. S. Volkov, Arkadii I. Leonov

College of Polymer Science and Polymer Engineering

A theory of non-Markovian translational Brownian motion in a Maxwell fluid is developed. A universal kinetic equation for the joint probability distribution of position, velocity, and acceleration of a Brownian particle is derived directly from the extended dynamic equations for the system. Unlike the extended Fokker-Planck equation which corresponds to Mori-Kubo generalized Langevin equation and provides only with calculations of one-time moments, the universal kinetic equation obtained gives complete statistical description of the process. In particular, an exact generalized Fokker-Planck equation in the velocity space valid for any time instant is derived for the free non-Markovian Brownian motion. It shows …

Time Dependence Of Tip Morphology During Cellular Dendritic Arrayed Growth, Hui Song, Surendra N. Tewari

Chemical & Biomedical Engineering Faculty Publications

Succinonitrile-1.9 wt pct acetone has been directionally solidified in 0.7 X 0.7-cm-square cross section pyrex ampoules in order to observe the cell/dendrite tip morphologies, not influenced by the ''wall effects,'' which are present during growth in the generally used thin (about 200 mu m) crucibles. The tips do not maintain a steady-state shape, as is generally assumed. Instead, they fluctuate within a shape envelope. The extent of fluctuation increases with decreasing growth speed, as the micro structure changes from the dendritic to cellular. The influence of natural convection has been examined by comparing these morphologies with those grown, without convection, …

Analysis Of Homogeneous Combustion In Monolithic Structures, Hendrik J. Viljoen

Papers in Chemical Reactions

An analytical method is used to solve the problem of homogeneous combustion in a monolith. The solid phase acts as burner support. Heat is conducted much more effectively in the solid phase and preheating of the gas is more effective. The flame temperature exceeds the adiabatic value. Solutions are presented for different velocities and feed concentrations.

An Investigation Of Learning Curves And Their Use In Simulation, Jennie H. Lommel

Theses and Dissertations

In 1995, the C-17 Factory Simulation Model (FSM) was developed to enable analysts to address 'what-if' questions about the resources required to build future aircraft, and is based on learning curve models that are used to both portray and simulate future aircraft production. In this thesis, we examine and develop alternate learning curve models that also utilize a small amount of initial production data to portray the relationship between the number of aircraft built and the resources required to build them. The goal is to identify a model which not only provides a good fit and forecast based on a …

Development Of A Simple, Analytical Method To Optimize Machining Cycles For Non-Cnc Gear Hobbing Machines, Steven M. Klabunde

Graduate Research Papers

The purpose of this research project was to develop a simple, analytical method for the optimization of hobbing cycles on non-CNC gear hobbing machines. Such a method would allow manufacturers to optimize hobbing cycle times, reduce part costs, and improve productivity. There have been many advances in gear cutting tool technology. Because of these advances, the capabilities of modern cutting tools are beyond the capabilities of non-CNC machines designed more than fifteen years ago. The majority of the machines used today in gear manufacturing are of this vintage. The cycles on these machine tools are machine-limited, which is much more …

An Enhanced Signal Processing Strategy For Fetal Heart Rate Detection, Charles Brewton

Electrical & Computer Engineering Theses & Dissertations

The goal of the research was to improve the signal processing strategy for an acoustic fetal heart rate monitor. The theory, implementation, and testing of several possible signal processing strategies for fetal heart rate detection are presented. The enhanced signal processing strategy implemented is discussed and justified with off-line Matlab simulations and real-time experiments. A FIR matched filter was used as a preprocessor to increase the SNR of the acoustic fetal heart signal. The Teager energy operator and autocorrelation, used in the previous version of the monitor, were combined with a matched filter. Linear prediction and quadratic energy detection were …

Frequency Response Enhancement Of A Flow Sensor Using Diamond Thin Films Synthesized By Plasma Cvd, John Curren Hagwood

Electrical & Computer Engineering Theses & Dissertations

Theoretical modeling conducted previously in our Microelectronics Laboratory has shown that a layer of diamond film inserted between a metal film and a substrate will enhance the frequency response of a conventional thin film flow sensor. This thesis involved fabricating and testing a conventional thin film sensor of nickel on quartz (Ni/Q) and a diamond enhanced sensor (Ni/D/Q) for comparative frequency response analysis to validate the theory. Diamond films were grown onto quartz substrates using a microwave plasma enhanced chemical vapor deposition process. Conditions were established to synthesize continuous diamond films on quartz substrates. These films were characterized by scanning …

Adaptive Integration Of Audio And Visual Information Using Discrete And Semi-Continuous Hidden Markov Models In Audiovisual Automatic Speech Recognition, Qin Su

Electrical & Computer Engineering Theses & Dissertations

An audiovisual semi-continuous hidden Markov model (HMM)-based Automatic Speech Recognition (ASR) system and an improved method of integrating audio and visual information in an audiovisual discrete HMM-based ASR system are investigated.

In the audiovisual discrete HMM, an adaptive integration formulation is employed, which incorporates the integration into the HMM at a pre-categorical stage. A visual weighting parameter is determined automatically, which allows the relative contribution of audio and visual information to be adjusted adaptively. Using an adaptive weight, the accuracy increased by 13% compared to the same model with no adaptive weight.

The semi-continuous HMM is a class of models …

Variable Step Size Lms Adaptive Filters With Delayed Coefficient Updating, Guixian Xu

Electrical & Computer Engineering Theses & Dissertations

A new approach to delayed LMS adaptive filtering is presented, which uses a variable step size for coefficient updating to increase convergence speed and improve tracking characteristics. The new algorithm, called delayed variable step size LMS (DVLMS), is explained, analyzed, and simulated to experimentally determine performance characteristics. Three different strategies for adjusting the step size are examined, and their performance is compared. Also, simulation results are presented to show that the proposed DVLMS systems provide faster convergence and lower mis-adjustment than previously proposed DLMS systems.

An Approach For Multidisciplinary Design Optimization, Robert V. Krueger

Mechanical & Aerospace Engineering Theses & Dissertations

Multidisciplinary Design Optimization (MDO) is an optimization technique that allows complex designs to be improved by managing conflicting goals in such a fashion so as to improve the overall design. This thesis presents a nonhierarchic MDO formulation and gives a general explanation of how it is to be applied to various appropriate problems. In addition, this thesis evaluates the viability of this MDO technique by applying it to two distinct, multidisciplinary problems that have been used as examples in other literature. The first example problem is a combined aerodynamic/structural problem and the second example is an alkylation process problem. First, …

Exact Solutions For Orthogonal And Non-Orthogonal Magnetohydrodynamic Stagnation-Point Flow, Shahrooz Moosavizadeh

Mathematics & Statistics Theses & Dissertations

The viscous plane flow of an electrically conducting fluid towards an infinite wall is solved in the presence of a magnetic field which is aligned with the flow far from the wall. The problem has two dimensionless parameters-- ε, the magnetic Prandtl number, and β, the square of the ratio of Alfven velocity to fluid velocity far from the wall. The problem has a similarity solution which reduces the governing equations to a system of coupled ordinary differential equations which can be solved numerically. For extreme values of ε, both large and small, singular perturbation techniques are used to derive …