Engineering Commons^™

Phonon And Magnetic Neutron Scattering At 41 Mev In Yba2cu3o7, Hung Fai Fong, Bernard Keimer, Pw Anderson, D. Reznik, Fatih Dogan, Ilhan A. Aksay

Materials Science and Engineering Faculty Research & Creative Works

We report inelastic neutron scattering measurements at excitation energies ħ⁢w∼41 meV in YBa₂Cu₃O₇. We separate magnetic and phonon contributions to the scattering cross section by a detailed analysis of the momentum dependence of the scattered intensity. The previously reported broad peak around q = (π/a,π/a) in the normal state can be entirely accounted for by a phonon which primarily involves vibrations of the in-plane oxygen. Magnetic scattering centered around 41 meV and q = (π/a,π/a) appears in the superconducting state only. Theoretical implications of …

Toward Determining Minimal/Optimal Transportation Department Resource Requirements: An Examination Of State Privatization Trends Among Selected States, Douglas J. Olberding

Kentucky Transportation Center Research Report

The purpose of this project was to conduct a preliminary analysis of employment and privatization trends in state transportation departments. This project involved a review of recent literature on public sector privatization efforts, an analysis of all state transportation departments in order to locate a sample of states with transportation system characteristics similar to those of Kentucky, and a survey of the sample states· to determine privatization trends in the functional areas of administration, maintenance, design, engineering, enforcement and safety, and construction.

The study finds that among transportation departments in the 14 sample states, average annual increases in private sector …

Pixel-Registered Image Fusion, Rufus H. Cofer, Samuel Peter Kozaitis

Electrical Engineering and Computer Science Faculty Publications

One of the highest potential uses of image fusion is that of recognition of critical targets. The continuing image fusion question then is how to make optimal use of the often disparate forms of encountered image detail during fusion. Toward this end, many techniques have been advanced for fusion to a single viewable image. Fewer techniques have been suggested toward fusion with the goal of directly improving target detection or recognition. Based upon emerging trends in pixel accurate registration of images, we show the theoretical foundations required to optimally fuse target imagery for recognition. Results obtained can be applied to …

Seasonal Hidden Markov Models For Stochastic Time Series With Periodically Varying Characteristics, Arthur M. Lewis

Dissertations and Theses

Novel seasonal hidden Markov models (SHMMs) for stochastic time series with periodically varying characteristics are developed. Nonlinear interactions among SHMM parameters prevent the use of the forward-backward algorithms which are usually used to fit hidden Markov models to a data sequence. Instead, Powell's direction set method for optimizing a function is repeatedly applied to adjust SHMM parameters to fit a data sequence. SHMMs are applied to a set of meteorological data consisting of 9 years of daily rain gauge readings from four sites. The fitted models capture both the annual patterns and the short term persistence of rainfall patterns across …

Acuta Enews July 1995, Vol. 24, No. 7

ACUTA Newsletters

In This Issue

Board report

President's message

Wiring today for tomorrow

Card technology

DC at a glance

From ACUTA Headquarters

Santa Clara Magazine, Volume 37 Number 3, Summer 1995, Santa Clara University

Santa Clara Magazine

6 - GARBAGE IN: GOODS OUT Lee Hornberger ' 69, associate professor of mechanical engineering, has only one word to say to you: plastics. By Maureen Mclnaney '85

10 - SCU 101 More than a hundred (count 'em) things every student shou ld do before graduating from Santa Clara.

16 - CHIAPAS: ROOTS OF A REBELLION Members of the SCU community bear witness to an indigenous struggle. By Trina Kleist '80 Photographs by Charles Barry

22 - PRESENTING PARADISE A modern translation with commentary helps readers scale the heights of Dante's heaven. By James Torrens, S.J.

24 - HAVE BALL, …

Impulse, Stacie Johnson, Cathy Nelson, Cindy Price, Jennifer Widman

Impulse (Jerome J. Lohr College of Engineering Publication)

Features:
[Page 2-4] College of Engineering impact felt throughout the state
[Page 5] Welding binds SDSU with community, industry
[Page 6] Engineering students create moving sign
[Page 7] Galipeau devises new humidity sensor
[Page 7] Alumnus heads engineering building project
[Page 8] South Dakota’s space involvement highlighted at Space Day
[Page 9] Grad students coordinate Space Grant Consortium balloon project
[Page 10] Andrawis, Flippin spend summer researching at NASA
[Page 11] Landscape architect wins summer faculty fellowship at EROS
[Page 12-13] NASA funds undergraduate research assistantships
[Page 14] Volga student assists ACE Camp
Departments:
Faculty:
[Page 15] Engineering professor Ritchie …

Acuta Enews July 1995, Vol. 24, No. 7

ACUTA Newsletters

In This Issue

Board report

Presidents message

Wiring today for tomorrow

Card technology

DC at a glance

From ACUTA Headquarters

A Direct Synthesis Method For The Conceptual Design Of Transport Aircraft, Pierre Andre Fruytier

Master's Theses - Daytona Beach

The problem of synthesizing a transport aircraft at the conceptual design level is considered. A direct sizing algorithm that does not require iteration is developed. Such direct synthesis methods can be used as important building blocks in an aircraft optimization process. New statistical equations based on current aircraft are derived for approximating the widths and lengths of the cabin and fuselage. A more accurate static thrust over gross weight, which is based on the equations of motion specified by the FAR part 25 climb requirements, is presented. A cruise at constant altitude with optional step-climb is taken into account. The …

Non-Linear Analysis Of Composite Beams With Web Opening, Ahemd Abdel-Baset Hassanein

Archived Theses and Dissertations

No abstract provided.

Generalized Beam Matrices: Gaussian Beam Propagation In Misaligned Complex Optical Systems, Anthony A. Tovar, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

A novel 3 × 3 transfer-matrix method is developed to propagate off-axis Gaussian beams in astigmatic optical systems that may include tilted, displaced, or curved optical elements. Unlike in a previous generalized ray matrix formalism, optical elements that possess gain or loss such as Gaussian apertures, complex lenslike media, and amplifiers are included; and a new beam transformation is found. In addition, a novel exponential variable-reflectivity mirror, which displaces a Gaussian beam without changing its spot size, and a complex prismlike medium are introduced.

The Dependence Of The Time-Asymptotic Structure Of 3-D Vortex Breakdown On Boundary And Initial Conditions, Jeffrey C. Tromp

Theses and Dissertations

The three-dimensional, compressible Navier-Stokes equations are solved numerically to simulate vortex breakdown in tubes. Time integration is performed with an implicit Beam-Warming algorithm, which uses fourth-order compact operators to discretize spatial derivatives. Initial conditions are obtained by solving the steady, compressible, and axisymmetric form of the Navier-Stokes equations using Newton's method. Stability of the axisymmetric initial conditions is assessed through 3-D time integration. Unique axisymmetric solutions at a Reynolds number of 250 lose stability to 3-D disturbances at a critical value of vortex strength, resulting in 3-D and time-periodic flow. Axisymmetric solutions at a Reynolds number of 1000 contain regions …

Stormwater Drainage Manual 1995, Christopher B. Burke, Thomas T. Burke

Indiana Local Technical Assistance Program (LTAP) Publications

This manual is a comprehensive catalog of procedures, design methods and criteria, and general background information which will enable the designer to quickly learn or review the basic principles of storm drainage design. Subjects included are the precipitation and hydrological cycle, runoff and its estimation, open channels, flow in gutters and inlets, stormwater storage, storm sewer system design, and computer applications for computing watershed runoff. Included in the appendices are basics of statistical analysis, fundamentals of hydraulics, a list of regulatory agencies and governmental bodies which may have jurisdiction over drainage projects, and TR-20 and TR-55 blank forms.

Studies Of Mixing Processes In Gases And Effects On Combustion And Stability, Frank Paul Kozusko Jr.

Mathematics & Statistics Theses & Dissertations

Three physical models of laminar mixing of initially separated gases are studied. Two models study the effects of the mixing dynamics on the chemical reactions between the gases. The third model studies the structure and stability of a laminar mixing layer in a binary gas. The three models are:

1. Two ideal and incompressible gases representing fuel and oxidizer are initially at rest and separated across an infinite linear interface in a two dimensional system. Combustion, expected as the gases mix, will lead to a rapid rise in temperature in a localized area, i.e. ignition. The mixing of the gases …

On The Reuse Of Bolts Which Have Been Torqued To Yield, Dal B. Lee, Joseph Foyos, Martin L. Smith, Omar S. Es-Said, Otto Kossuth

Mechanical Engineering Faculty Works

Bolts are torqued to yield in automotive engines to fasten aluminum alloy cylinder heads to cast iron cylinder blocks. This tightening method provides a reliable, even, and controllable clamping force that prevents warping of the soft cylinder head and ensures a leak-tight joint. It has one drawback: Since the bolts yield during engine assembly, they work harden even as their ultimate strength decreases. Upon reuse, yield stress more closely approaches ultimate strength. Fastener geometry and mechanical properties, now changed, supply changed joint-clamping force. For reasons such as these. Ford Motor Company recommends that bolts torqued to yield be replaced each …

Tolerance Theory Of Periodic Surfaces, James A. Godsey

Theses and Dissertations

Two formulations for the far field statistical average power pattern of a strip grating with errors in strip and slit width are presented. The first formulation utilizes the Born approximation in which the unknown aperture fields are replaced by the incident fields. The second formulation utilizes an approximation which satisfies the edge condition. Approximations for the scattered fields are first derived using PEC surface equivalence for a TEz polarized plane wave incident upon a strip grating consisting of an infinite PEC screen cut by a number of infinitely long slits. Babinet's principle is then used to obtain approximations for the …

Ohmic Contact To Ion Implanted Gallium Arsenide Antimonide For Application To Indium Aluminum Arsenide-Gallium Arsenide Antimonide Heterostructure Insulated-Gate Field Effect Transistors, Kenneth G. Merkel Ii

Theses and Dissertations

The p-channel In_0.52Al_0.48As-GaAs_1-xSb_x heterostructure insulated-gate field effect transistor (p-HIGFET) is a candidate for complementary integrated circuits due to superior cutoff characteristics and low gate leakage current. Advancement of the In_0.52Al_0.48As-GaAs_1-xSb_x p-HIGFET requires improved source-drain design. Five main tasks were accomplished to achieve this goal. First, thermal limits of the In_0.52Al_0.48As-GaAs_0.51Sb_0.49 HIGFET were investigated. Second, the temperature dependence of band gap and impurity energies were determined for beryllium doped In_0.52Al_0.48. Third, high acceptor concentrations were obtained …

Comparison Of System Identification Techniques For The Dexterous Orbital Servicing System (Doss), Allan Terrence Morris

Electrical & Computer Engineering Theses & Dissertations

The major contribution of system identification is the development of analytical models of a system. Many identification techniques can adequately describe the input and output map. One of the challenges of these techniques is to correctly infer from the measured data the characteristics of the individual, contributing components producing a more accurate system model.

In this thesis linear, dynamic, multivariable state-space models for three joints of the Dexterous Orbital Servicing System (DOSS) are identified. DOSS is a representative space station manipulator at the NASA Langley Research Center. The dynamic models of the manipulator will first be estimated by applying nonparametric …

Ballast Size For Safe Working Conditions In Railroad Yards And Terminals In Kentucky, Jerry G. Rose

Kentucky Transportation Center Research Report

During the 1994 Regular Session of the House of Representatives of the General Assembly of the Commonwealth of Kentucky, House Resolution No. 58 was introduced by Representative J. Dorsey Ridley on Monday, February 28. It basically directed the Transportation Cabinet "to identify the more appropriate grade of rock used as surface material in railroad beds and walkways" and that "any remedy proposed... be reported to the Legislative Research Commission no later than August 1, 1995." A copy of the Resolution is contained in Appendix A.

The issue was forwarded to the Transportation Cabinet and subsequently to the Kentucky Transportation Center …

Precision Total Pressure Measurements Of Propyne With Propane, Propene, And Propadiene, Edward A. Kyser, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

Experimental total pressure measurements of propyne mixed with propane, propene, and propadiene are presented for five isotherms from 253 to 353 K. Thermodynamically consistent vapor compositions and saturated phase densities are calculated using a cubic equation of state with three isothermal pure component parameters and two binary mixture parameters. The precision vapor—liquid equilibrium cell and experimental procedure which are particularly useful for measurements involving close boiling light hydrocarbons are described, and the experimental and modeled results are presented. © 1995, American Chemical Society. All rights reserved.

Liquid Crystal-On-Silicon Implementation Of The Partial Pixel Three-Dimensional Display Architecture, M. W. Jones, Gregory P. Nordin, M. Friends, S. T. Kowel, J. H. Kulick, R. G. Lindquist, P. J. Nasiatka

Faculty Publications

We report the implementation of a liquid crystal-on-silicon, three-dimensional 13-D2 diffractive display based on the partial pixel architecture. The display generates multiple stereoscopic images that are perceived as a static 3-D scene with one-dimensional motion parallax in a manner that is functionally equivalent to a holographic stereogram. The images are created with diffraction gratings formed in a thin liquid crystal layer by fringing electric fields from transparent indium tin oxide interdigitated electrodes. The electrodes are controlled by an external drive signal that permits the 3-D scene to be turned on and off. The display has a contrast ratio of 5.8, …

Nonlinear Transient Thermal Analysis By The Force-Derivative Method, Narayani V. Balakrishnan

Mechanical & Aerospace Engineering Theses & Dissertations

The force-derivative method (FDM) represents a series of higher-order modal methods which offer an increasingly improved approximation of the higher modes neglected in the basic mode-displacement method (MDM). The FDM includes additional terms which involve the forcing function and derivatives of the forcing function with respect to time. The mode-acceleration method (MAM), extensively used in structural analysis, is a first-order form of the FDM which includes only one correction term that depends on the forcing function itself. The success of the FDM in many structural dynamic applications has prompted its application for solving transient thermal problems. The superior convergence of …

Dynamic Unstructured Method For Prescribed And Aerodynamically Determined Relative Moving Boundary Problems, Kamakhya Prasad Singh

Mechanical & Aerospace Engineering Theses & Dissertations

A new methodology is developed to simulate unsteady flows about prescribed and aerodynamically determined moving boundary problems. The method couples the fluid dynamics and rigid-body dynamics equations to capture the time-dependent interference between stationary and moving boundaries. The unsteady, compressible, inviscid (Euler) equations are solved on dynamic, unstructured grids by an explicit, finite-volume, upwind method. For efficiency, the grid adaptation is performed within a window around the moving object. The Eulerian equations of the rigid-body dynamics are solved by a Runge-Kutta method in a non-inertial frame of reference. The two-dimensional flow solver is validated by computing the flow past a …

Numerical Investigation Of Shock-Induced Combustion Past Blunt Projectiles, Jagjit K. Ahuja

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical study is conducted to simulate shock-induced combustion in premixed hydrogen-air mixtures at various free-stream conditions and parameters. Two-dimensional axisymmetric, reacting viscous flow over blunt projectiles is computed to study shock-induced combustion at Mach 5.11 and Mach 6.46 in hydrogen-air mixture. A seven-species, seven reactions finite rate hydrogen-air chemical reaction mechanism is used combined with a finite-difference, shock-fitting method to solve the complete set of Navier-Stokes and species conservation equations. In this approach, the bow shock represents a boundary of the computational domain and is treated as a discontinuity across which Rankine-Hugoniot conditions are applied. All interior details of …

Fault Tolerant Pipelined Adaptive Systems, Bhasker Reddy Allam

Electrical & Computer Engineering Theses & Dissertations

A fault tolerant pipelined architecture for high sampling rate adaptive filters is presented in this thesis. The architecture is based on the computational requirements of delayed LMS and lattice adaptive 61ters. It offers robust performance in the presence of single hardware faults, and software faults resulting from numerical instability. Two different architectures are proposed. One allows a graceful degradation in system performance in the event of a fault, and the other uses a module replacement strategy to recover from faults without decreasing performance. Analysis of the steady state error increase due to filter reconfiguration is presented. The reliability of the …

Fault Tolerance In Critical Real-Time Systems, Balaji Tirukarneswaran

Electrical & Computer Engineering Theses & Dissertations

Critical real-time applications require work to be completed before a predefined deadline, else the consequences may be catastrophic. The anticipation of faults in such systems necessitates the need for fault tolerance. Fault tolerance can be achieved in many different ways. A real-time system designer may impose restrictions on any of the system performance measures such as the latency, throughput and number of processors, depending on the type of application. In this work, several different fault tolerant strategies for any given DFG (Data Flow Graph) are discussed. DFG models are developed using the strategies and the resulting worst case performances a.re …

Multiresolution Binary Optical Correlator Using The Wavelet Transform, Samuel Peter Kozaitis

Electrical Engineering and Computer Science Faculty Publications

We used morphological filters to approximate wavelet scaling functions for multiresolution processing of an image. Because some spatial light modulators (SLMs) can only display binary data, wavelet processing of binary images is inhibited. Therefore, we considered an alternative way - morphological processing - to generate a wavelet representation that consists entirely of binary elements. The effects of these filters are dependent on the input signal and cannot be generalized. Therefore, we used a statistical approach to approximate the scaling functions or various wavelets using morphological filters. ©2005 Copyright SPIE - The International Society for Optical Engineering.

Circulation Measurements About A Rapidly Pitching Airfoil Using An Ultrasonic System, F. J. Weber, Jr., William W. Durgin, H. Johari

Office of the Provost Scholarship

An ultrasonic system was developed to measure the circulation about a sinusoidally pitching NACA 4418 airfoil. The system consisted of two opposing ultrasonic ranging modules arranged such that the differences between the sound propagation times in opposite directions could be related to the instantaneous circulation. For the stationary airfoil, the measured lift coefficient was within 5% of the tabulated data while the observed stall angle was 2° less than the tabulated value. Measured hysteresis loops verified the applicability of the ultrasonic system to the dynamic stall problem. Measured maximum lift coefficients increased linearly with reduced frequency up to a value …

Development Of A Graduate Integrated Waste Management Course Using The Case Study Approach, Samuel A. Vigil

Civil and Environmental Engineering

Solid waste management is an integral part of the environmental engineering profession. At California Polytechnic State University (Cal Poly), solid waste management is taught as a required course in an undergraduate environmental engineering curriculum. The undergraduate course is described in Reference 1. This paper discusses the development of a graduate level integrated waste management course entitled "Resource and Energy Recovery from Waste", which uses a case study approach. The course focuses on resource and energy recovery technologies including composting, unit operations of resource recovery, recycling, and thermal waste conversion including combustion and gasification. The bioconversion of wastes in landfills and …

Field Commissioning Of A Daylight-Dimming Lighting System, Florida Solar Energy Center, David Floyd

FSEC Energy Research Center®

An Elementary School cafeteria in Florida was commissioned with a fluorescent lighting system that dims in response to available daylight. The lighting system's performance and commissioning aspects were evaluated through real time measurement of lighting and air conditioning power, work plane illumination, and interior/exterior site conditions. The new system produced a 27% reduction in lighting power due to dimming. Lower than expected dimming system performance was observed prior to effective commissioning. Difficulties encountered are discussed as well as recommendations for performance improvements.