Engineering Commons^™

Status Report On The Antarctic Meteorological Research Centermay 2003 To May 2004, Matthew A. Lazzara, Charles R. Stearns, Linda M. Keller, Jessica A. Staude

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Matthew A. Lazzara, Shelley L. Knuth, Charles R. Stearns, Linda M. Keller, and Jessica A. Staude titled "Status Report on the Antarctic Meteorological Research CenterMay 2003 to May 2004" from June 8, 2004.

Plans For 2004/2005 Mcmurdo Based Operations, John Cassano, Thomas R. Parish

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Joh Cassano and Thomas R. Parish titled "Plans for 2004/2005 Mcmurdo Based Operations" from June 7, 2004.

Excited States Of Silicon Carbide Clusters By Time Dependent Density Functional Theory, John E. Boyd

Theses and Dissertations

Previous AFIT research with density functional theory (DFT) has shown itself to be accurate for small Si_mC_n (m,n ≤ 5) clusters at a fraction of the cost of other quantum mechanical methods, but it is only a ground state theory. Time dependent density functional theory (TDDFT), however, is able to calculate excited states as well. Evaluating the accuracy of these methods with respect to the excited states of these clusters was the focus of this research, specifically with respect to the excitation energies, geometries, and vibrational frequencies. It is shown that for the excited states that can …

Morpheus: Motif Oriented Representations To Purge Hostile Events From Unlabeled Sequences, Guarav Tandon, Debasis Mitra, Philip K. Chan

Electrical Engineering and Computer Science Faculty Publications

Most of the prevalent anomaly detection systems use some training data to build models. These models are then utilized to capture any deviations resulting from possible intrusions. The efficacy of such systems is highly dependent upon a training data set free of attacks. "Clean" or labeled training data is hard to obtain. This paper addresses the very practical issue of refinement of unlabeled data to obtain a clean data set which can then train an online anomaly detection system. Our system, called MORPHEUS, represents a system call sequence using the spatial positions of motifs (subsequences) within the sequence. We also …

Aerodynamic Analysis Of Lattice Grid Fins In Transonic Flow, Karl S. Orthner

Theses and Dissertations

Lattice grid fins have been studied for missile tail control for several years. A lattice grid fin can be described as an unconventional missile control surface comprised of an outer frame supported by an inner lattice grid of lifting surfaces. This unconventional fin design offers favorable lift characteristics at high angle of attack as well as almost zero hinge moments allowing the use of small and light actuators. In addition, they promise good storability for potential tube-launched and internal carriage dispenser-launched applications. The drawback for the lattice grid fins is the high drag and potentially poor radar cross section performance …

Magnetogasdynamic Flow Acceleration In A Scramjet Nozzle, Brian H. Harrington

Theses and Dissertations

The effect of magnetogasdynamic (MGD) interactions on flow acceleration and thrust in a scramjet accelerator/nozzle are examined numerically at a free-stream flight condition of Mach 8. The parameters of conductivity pattern and load factor are varied in both inviscid and viscous flow regimes with the intent of increasing axial force exerted on the flow through a scramjet accelerator. The numerical code solves the Navier-Stokes equations with additional source terms for the MGD forces and energy interactions. An accelerating Lorentz force is applied to the flow resulting from a constant magnetic field and an electric field produced by two continuous side …

The Structure Of The High-Energy Spin Excitations In A High-Transition-Temperature Superconductor, S. M. Hayden, H. A. Mook, Pengcheng Dal, T. G. Perring, F. Doǧan

Materials Science and Engineering Faculty Research & Creative Works

In conventional superconductors, lattice vibrations (phonons) mediate the attraction between electrons that is responsible for superconductivity. The high transition temperatures (high-Tc) of the copper oxide superconductors has led to collective spin excitations being proposed as the mediating excitations in these materials. The mediating excitations must be strongly coupled to the conduction electrons, have energy greater than the pairing energy, and be present at Tc. The most obvious feature in the magnetic excitations of high-Tc superconductors such as YBa 2Cu3O6+x is the so-called 'resonance'. Although the resonance may be strongly coupled to the superconductivity, it is unlikely to be the main …

Detached Eddy Simulation Analysis Of Pak-B Low Pressure Turbine Blade, Kyle Malone

Theses and Dissertations

Two cases were computationally investigated using the detached eddy simulation (DES) turbulence model: an unmodified Pak-B blade and a Pak-B blade with a dimple located at 65% of axial chord. Both cases were created so that they simulated an infinite span with an infinite number of dimples. The cases were run for an inlet Reynolds number of 25,000. The computed results were used to resolve the location of separation and reattachment, visualize the streamlines for the dimpled case, build velocity magnitude contour and vector plots, and map the thickness of the boundary layer. The results were then compared to previous …

Acuta Enews June 2004, Vol. 33, No. 6

ACUTA Newsletters

In This lssue

Make Plans to Attend Annual Conference

From the President............................. Walter L. Czerniak, Northern Illinois University

URGENT: ITFS Spectrum at Risk

Tech Talk........................ Kevin Tanzillo, Dux Public Relations

FCC Releases Study on Telephone Trends

Preconference Seminars Address Timely Topics

DC Update.......................... Whitney Johnson, Retired, Northern Michigan Univ.

Unexpected Dangers in the Plenum................. Frank Bisbee, Communications Planning Corp.

ACUTA Member Sites to See

Board Report......................... Carmine Piscopo, Providence College, ACUTA Secretary/Treasurer

Welcome New Members

Geon: Geophysical Data Add The 3rd Dimension In Geospatial Studies, R. Aldouri, George R. Keller, Ann Q. Gates, J. Rasillo, Leonardo Salayandia, Vladik Kreinovich, John M. Seeley, P. Taylor, S. Holloway

Departmental Technical Reports (CS)

A major trend in GIS is the addition of subsurface information to provide a 3-D perspective on data. Geophysical data provide information about subsurface structures and conditions, but require considerable analysis. The 4-D emphasis with the GEON projects has required the development of many sophisticated tools to allow users to utilize geophysical datasets that will be available on the GEON grid. Our group has created tools that will allow users to search new gravity and magnetic databases of the entire U.S. These tools will extract specific records from an Oracle database, and display the points over a map, grid and …

Computing Higher Central Moments For Interval Data, Vladik Kreinovich, Luc Longpre, Scott Ferson, Lev Ginzburg

Departmental Technical Reports (CS)

Higher central moments are very useful in statistical analysis: the third moment M3 characterizes asymmetry of the corresponding probability distribution, the fourth moment M4 describes the size of the distribution's tails, etc. When we know the exact values x1,...,xn, we can use the known formulas for computing the corresponding sample central moments. In many practical situations, however, we only know intervals [x1],...,[xn] of possible values of xi; in such situations, we want to know the range of possible values of Mm. In this paper, we propose algorithms that compute such ranges.

One-Tap Wideband I/Q Compensation For Zero-If Filters, Peter Kiss, Vladimir I. Prodanov

Electrical Engineering

The I/Q imbalance is one of the performance bottlenecks in transceivers with stringent requirements imposed by applications such as 802.11a. The mismatch between the frequency responses of two analog low-pass filters, used, e.g., for channel selection in zero-IF receivers, makes this I/Q imbalance frequency dependent. Usually, frequency-dependent I/Q mismatch is estimated and corrected by adaptive techniques, which are complex to implement and may converge slowly due to noise. In this work, a simple, delay-based I/Q compensation scheme is proposed based on an extensive statistical analysis. Its digital implementation uses only two coefficients, which are tuned by a one-step two-tone error …

The Influence Of Academic Dishonesty On Ethical Decision- Making In The Workplace: A Study Of Engineering Students, Trevor S. Harding, Donald D. Carpenter, Cynthia J. Finelli, Honor J. Passow

Materials Engineering

According to studies conducted over the past four decades, engineering students self-report high frequencies of academic dishonesty (cheating) while in college. Research on college students in all fields has indicated that such behavior is more common among students who participate in academic dishonesty at the high school level and that it is correlated with other deviant or unethical behaviors, such as petty theft and lying. If, in fact, such correlations do exist, one might hypothesize that there is also a relationship between academic dishonesty in college and deviant or unethical behavior in professional practice. Placing this relationship in the context …

Life Cycle Assessment As A Tool For Green Manufacturing Education, Trevor S. Harding

Materials Engineering

The design and production of engineering products that have a reduced impact on the environment and human health has increasingly become a strategic goal of corporations. Consequently, starting engineers will need to be educated in green design techniques. One method that is particularly attractive to engineers is Life Cycle Assessment (LCA). LCA is an objective approach to evaluating the environmental burden of a product, process or activity by identifying and quantifying material and energy usage and waste outputs at every life stage. LCA involves three steps: identification of scope of analysis, life cycle inventory, and impact analysis. Such an approach …

Does Academic Dishonesty Relate To Unethical Behavior In Professional Practice? An Exploratory Study, Trevor S. Harding, Donald D. Carpenter, Cynthia J. Finelli, Honor J. Passow

Materials Engineering

Previous research indicates that students in engineering self-report cheating in college at higher rates than those in most other disciplines. Prior work also suggests that participation in one deviant behavior is a reasonable predictor of future deviant behavior. This combination of factors leads to a situation where engineering students who frequently participate in academic dishonesty are more likely to make unethical decisions in professional practice. To investigate this scenario, we propose the hypotheses that (1) there are similarities in the decision-making processes used by engineering students when considering whether or not to participate in academic and professional dishonesty, and (2) …

A Recommendation For An Enhanced Fujita Scale (Ef-Scale)

United States Department of Commerce: Staff Publications

Background

National Weather Service (NWS) personnel who are responsible for rating tornadoes have expressed frustrations in applying the Fujita Scale in a consistent and accurate manner. Weak links in a structural system or a slow-moving storm sometimes lead to an overrating of a tornado event. Several technical articles suggest that wind speeds associated with some descriptions of damage are too high. For example, a 260 mph wind speed is not required to completely destroy a well constructed house and blow away the debris. The damage occurs at significantly lower wind speeds. Minor et al. (1977) and Phan and Simiu (2003) …

Crystallization Kinetics Study Of The Glasses In Se–Te System, Fareed Abdul Raheem Al-Gheyath

Theses

The aim of the present work is to study the crystallization kinetics of some chalcogenide glassy alloys in the Selenium-Tellurium system. Four glassy systems have been prepared: Se₈₀Te_20-xSb_x (x= 0, 4, 6, 8, and 10); Se₇₀Te_30-xSb_x (x= 2, 6, 8, and 10); Se₈₀Te_20-xCd_x (x= 2, 4, and 10); and Se₈₀Te_20-xSn_x (x= 2, 4, and 10). The starting materials of (99.999%) purity were weighted according to their atomic percentages and sealed in evacuated silica tubes, under a pressure of about 10 …

Investigation Into The Current Statistical Distribution For Oxide Breakdown Versus The Oxide Thickness Used In Integrated Circuit Manufacture, Eoin James O Driscoll

Theses

A critical aspect of integrated circuit manufacturing is the reliability of the components, in particular the gate oxide of transistors and capacitors. Accelerated stress tests are used for reliability predictions of gate oxides. There are two statistical distributions, which can be applied to stress test failure data, namely the Lognormal or the Weibull distributions. The failure data can fit each distribution equally well. However the use of either distribution will give vastly different lifetime predictions and their correct use is crucial for accurate lifetime prediction. A statistical based test, developed with Monte Carlo data, which is designed to decide if …

Isomer Heat Exchanger Combustor Replacement For A Supersonic Ramjet Powered Vehicle, Jonathan C. Cox

Theses and Dissertations

This study investigated the possibility of utilizing a Triggered Isomer Heat Exchanger (TIHE) within a ramjet engine to power a supersonic Conventional Air Launched Cruise Missile (CALCM). A computational ramjet engine was created using engine analysis software. This model was then run through a simulated cruise missile mission using AEDsys, a mission analysis and engine performance software suite. The replacement of the combustor with a TIHE led to an impressive range increase for the supersonic cruise missile.

Aeroelastic Analysis Of A Joined-Wing Sensorcraft, Jennifer J. Sitz

Theses and Dissertations

This study performed an aeroelastic analysis of a joined-wing SensorCraft. The analysis was completed using an aluminum structural model that was splined to an aerodynamic panel model. The force and pressure distributions were examined for the four aerodynamic panels: aft wing, fore wing, joint, and outboard tip. Both distributions provide the expected results (elliptical distribution), with the exception of the fore wing. The fore wing appears to be affected by interference with the joint. The use of control surfaces for lift and roll was analyzed. Control surfaces were effective throughout most of the flight profile, but may not be usable …

Target Recognition Using Late-Time Returns From Ultra-Wideband, Short-Pulse Radar, Kenneth J. Pascoe

Theses and Dissertations

The goal of this research is to develop algorithms that recognize targets by exploiting properties in the late-time resonance induced by ultra-wide band radar signals. A new variant of the Matrix Pencil Method algorithm is developed that identifies complex resonant frequencies present in the scattered signal. Kalman filters are developed to represent the dynamics of the signals scattered from several target types. The Multiple Model Adaptive Estimation algorithm uses the Kalman filters to recognize targets. The target recognition algorithm is shown to be successful in the presence of noise. The performance of the new algorithms is compared to that of …

Estimating Equatorial F-Region Daytime Vertical E X B Drift Velocities From Ground-Based Magnetometer Measurements In The Philippine Longitude Sector, Shauna M. Kinkela

Theses and Dissertations

Ionospheric disturbances can severely impact Department of Defense (DoD) systems, such as radar. satellite. and navigation technologies. Forecasting disturbances and describing the Earth's ionosphere, in turn, relies upon innovative computer-based models that gather input parameters from ground and space-borne observations and empirical models for ionospheric drivers. Equatorial E x B drift velocities are significant input parameters that go into many ionospheric models, because they help describe vertical plasma motions near the magnetic equator. Previous work by Anderson, et al 2002 has demonstrated the ability to derive Peruvian longitude sector, daytime vertical E x B drifts from ground-based magnetometer data. The …

Comparative Study On The Use Of Coherent Radar-Derived Electric Fields Vs. Statistical Electric Fields For The Initialization Of A High-Latitude Ionospheric Model, Christopher M. Hogue

Theses and Dissertations

The structure and time development of the magnetosphere-ionosphere system have significant impacts on the Air Force and its mission. Specifically, an accurate knowledge of ionospheric plasma densities is important for the operation of many Air Force systems. This research analyzes plasma density structure development through comparing two distinct electric field models. The two models compared here are a commonly used statistical model created by Heppner and Maynard 1987, and a more recently developed model using real-time coherent radar measurements from the SuperDARN radar network. Ionospheric simulations were run using Utah State University s Time-Dependent Ionospheric Model (TDIM) with the two …

Shock Tube Investigation Of Pressure And Ion Sensors Used In Pulse Detonation Engine Research, Robert J. Mcmillan

Theses and Dissertations

Shock tubes utilize a difference in pressures between gases separated by a diaphragm to create a shock wave when the diaphragm ruptures. By using sensors of known spacing, the speed of the wave can be determined. The AFIT 2-inch shock tube was reassembled and tested to ensure proper and safe operation. A high-speed data acquisition system was configured to take data at 2 MS/s. This research showed that the Mach number of the shock waves produced in this shock tube fall within 7% of theoretical values at speeds under Mach 3 and within 9% at higher speeds. The peak velocity …

Extending The Aircraft Availability Model To A Constrained Depot Environment Using Activity-Based Costing And The Theory Of Constraints, Gerardo H. Acosta Voegeli

Theses and Dissertations

The Aircraft Availability Model (AAM) assists managers in the selection of an optimal list of items to repair in order to attain the best aircraft availability rate. The model considers procurement or repair costs for the components as if the costs were unit variable as a price, instead of a repair cost representing a mix of both fixed and variable cost. This research used the AAM in conjunction with Activity Based-Costing (ABC) and The Theory of Constraints (TOC) methodologies to investigate the relationships between price, product mix, Aircraft Availability (AA) and total cost. This approach explicitly recognizes that the Air …

Implementing Institute Of Electrical And Electronics Engineers (Ieee) 802.11 Standard Medium Access Control Protocol For Wireless Local Area Networks (Lans) On A Laboratory Hardware Prototype, Joshua D. Green

Theses and Dissertations

Wireless Local Area Networks (LANs) are extremely convenient, flexible, and easy to deploy. All LANs in which multiple hosts must access the same medium use a Medium Access Control (MAC) protocol to coordinate channel access. The MAC is part of the Data Link Layer of the Open Systems Interconnection (OSI) Reference Model. One MAC protocol in extensive use today is the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. Since IEEE 802.11 devices are so prevalent in today s world, many researcher are exploring modifications and enhancements to the protocol. There are several well developed analytical and simulation models …

Debt Capacity And Debt Limits: A State Road Fund Perspective, Merl Hackbart, Suzanne Perkins Sapp, Yongbeom Hur

Kentucky Transportation Center Research Report

State governments are facing major transportation infrastructure financing challenges as highway or Road Fund revenue growth has slowed and resistance to tax increases has strengthened. As a result, state transportation officials have turned to other financing methods to maintain momentum in meeting highway construction and maintenance needs. Among the financing methods being considered is the expansion of bond or debt financing. Changes in federal legislation that permits states to “pre-obligate” future federal funds, among other considerations, has made debt financing an attractive alternative for the states. As states consider the expanded use of this financing strategy, several financial management questions …

Implementation Of Conductive Concrete Overlay For Bridge Deck Deicing At Roca, Nebraska, Christopher Y. Tuan, Sherif A. Yehia

Civil Engineering Faculty Proceedings & Presentations

Conductive concrete is a relatively new material technology developed to achieve high electrical conductivity and high mechanical strength. In research sponsored by Nebraska Department of Roads, a conductive concrete mix specifically for bridge deck deicing was developed. In this application, a conductive concrete overlay is cast on top of a bridge deck for deicing and anti-icing.

This technology has been successfully implemented in a demonstration project at Roca, about 15 mi south of Lincoln, Nebraska. The Roca Spur Bridge has a 36-m (117-ft) long and 8.5- m (28-ft) wide conductive concrete inlay. Temperature sensors and a microprocessor-based controller system were …

Role Of Curvature Elasticity In Sectorization And Ripple Formation During Melt Crystallization Of Polymer Single Crystals, Rujul Mehta, Wirunya Keawwattana, Andrew L. Guenthner, Thein Kyu

College of Polymer Science and Polymer Engineering

The present article focuses on theoretical elucidation of possible effect of mechanical deformation on spatio-temporal emergence of unusual polymer morphology subjected to quiescent isothermal crystallization conditions. The present theory developed is based on a phase field model consisted of non-conserved time dependent Ginzburg-Landau equation having an asymmetric double well potential in the crystal order parameter signifying metastability for crystallization, coupled with the chain tilt angle involving curvature elasticity and strain recovery potentials. Under quiescent crystallization conditions, the curvature elasticity term is needed to discern the emergence of sectorized single crystals. Upon coupling with the strain recovery potential, the numerical calculation …

Modification Of Statistical Threading In Two-Component Pseudorotaxane Melts Using The Amphiphilic Approach And Variations In The Confinement Geometry, Sagar S. Rane, Wayne L. Mattice, Coleen Pugh

College of Polymer Science and Polymer Engineering

Recently we described a coarse-grained model of poly(ethylene oxide) and then employed that model to study the amount of spontaneous threading of cyclic molecules by linear chains in the melt [C. A. Helfer, G. Xu, W. L. Mattice, and C. Pugh, Macromolecules 36, 10071 (2003)]. Since the amount of statistical threading at equilibrium is small, there is interest in identifying physical changes in the system that will increase the threading. We now use that coarse-grained model to investigate the effect on threading of various hypothetical (but feasible) modifications to the two-component system of macrocycles and linear chains in the melt, …