Engineering Commons^™

Nebraska Summary: S279 Massey Ferguson 4253, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Modeling The Dielectric Response And Relaxation Spectra Of Relaxor Ferroelectrics, Huh Tswen Lin, David C. Van Aken, Wayne Huebner

Materials Science and Engineering Faculty Research & Creative Works

A multi-Debye relaxation model that is based upon the Boltzmann superposition principle has been used to determine the frequency-dispersion behavior of Pb (Mg_1/3-Nb_2/3)O₃ (PMN) and Pb_0.88La_0.08 (Zr_0.65Ti_0.35) O₃ (PLZT 8/65/35) relaxor ferroelectrics. For PMN, relaxation times on the order of seconds contribute to the dispersive character of the dielectric properties. A defect-relaxation mechanism that involves Mg cation hopping in a structure that is composed of interpenetrating 〈111〉 chains of ordered Pb (Mg_1/2Nb_1/2) O₃ is proposed for PMN. Motion of the Mg cations …

Test 1762: White 6510 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Nuclear Fuel Pellet Inspection Using Artificial Neural Networks, Shahla Keyvan, Xiaolong Song, Mark Kelly

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Nuclear fuel must be of high quality before being placed into service in a reactor. Fuel vendors currently use manual inspection for quality control of fabricated nuclear fuel pellets. In order to reduce workers' exposure to radiation and increase the inspection accuracy and speed, the feasibility of automation of fuel pellet inspection using artificial neural networks (ANNs) is studied in this paper. Three kinds of neural network architectures are examined for evaluation of the ANN performance in proper classification of good versus bad pellets. Two supervised neural networks, back-propagation and fuzzy ARTMAP, and one unsupervised neural network called ART2-A are …

The Hygrothermal Response And Physical Aging Of Polymer Matrix Textile Composites, Natalie L. Dixon

Masters Theses

"Woven graphite/epoxy composite laminate is one type of composite currently being investigated for use in aircraft engine components. However, polymers tend to become brittle with age, especially when exposed to elevated temperature. It is necessary to understand the physical changes in a material during the aging process in order to predict the long-term behavior.

In addition to aging, materials used in aircraft will be exposed to a wide variety of temperatures and relative humidity levels. Variations in temperature and moisture content affect both the physical and the mechanical properties of composites.

Experimental methods are described for hygrothermal testing of a …

The Dynamics Of Rotor With Rubbing, Jerzy T. Sawicki, Joe Padovan, Rabih Al-Khatib

Mechanical Engineering Faculty Publications

This paper presents the description of some phenomena associated with dynamic behavior of rotors interacting with stationary components. Numerical simulations show rotor vibration spectrum rich in subharmonic, quasi-periodic, and chaotic vibrations. The nonlinear calculation techniques are applied to demonstrate the changes of the vibration patterns for different operating conditions. Some conclusions are discussed with regard to unique characteristics of rub-induced rotor response, initial conditions, as well as appropriate ranges of system parameters. Of special interest are the changes in the apparent nonlinearity of the system dynamics as rubs are induced at different rotor speeds. In particular, starting with 2nd order …

Analysis Of A Lithium/Thionyl Chloride Battery Under Moderate-Rate Discharge, Mukul Jain, Ganesan Nagasubramanian, Rudolph G. Jungst, John W. Weidner

Faculty Publications

A one-dimensional mathematical model of a spirally wound lithium/thionyl chloride primary battery is developed and used for parameter estimation and design studies. The model formulation is based on the fundamental conservation laws using porous electrode theory and concentrated solution theory. The model is used to estimate the transference number, the diffusion coefficient, and the kinetic parameters for the reactions at the anode and the cathode as a function of temperature. These parameters are obtained by fitting the simulated capacity and average cell voltage to experimental data over a wide range of temperatures (–55 to 49°C) and discharge loads (10-250 ). …

A Compensated Acoustic Actuator For Systems With Strong Dynamic Pressure Coupling, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

This study improves the performance of a previously developed acoustic actuator in the presence of an acoustic duct system with strong pressure coupling. The speaker dynamics and the acoustic duct dynamics are first modeled separately. The two systems are then coupled, and the resulting system is modeled. A velocity sensor is developed and used in feedback compensation. The resulting speaker system has minimal magnitude and phase variation over a 20–200 Hz bandwidth. These conclusions are verified through experimental results.

Implementation And Performance Study Of Image Data Hiding/Watermarking Schemes, Arkadiusz Edward Komenda

Theses

Two data hiding / watermarking techniques for grayscale and color images are presented. One of them is DCT based, another uses DFT to embed data. Both methods were implemented in software utilizing C/C++. The complete listings of these programs are included. A comprehensive reliability analysis was performed on both schemes, subjecting watermarked images to JPEG, SPIRT and MPEG-2 compressions. In addition, the pictures were examined by exposing them to common signal processing operations such as image resizing, rotation, histogram equalization and stretching, random, uniform and Gaussian noise addition, brightness and contrast variations, gamma correction, image sharpening and softening, edge enhancement, …

Hypersonic Drag And Heat Transfer Reduction Using A Forward Facing Jet, Benjamin Meyer, Harlan F. Nelson, David W. Riggins

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A two-dimensional numerical study of the effects of a forward-facing jet located at the stagnation point of a blunt body on wave drag, heat transfer, and skin friction drag is presented for Mach 6.5 flow at 30 km altitude. The full Navier-Stokes equations are used with variable viscosity and thermal conductivity. It is shown that upstream injection can significantly modify the flow field. If the jet conditions are chosen properly, large reductions in drag and heat transfer can be obtained resulting in possible increases in the volumetric efficiency and static stability of aircraft and reductions in heating protection requirements for …

A New Reflection Free Boundary In Uniform Flow Using Mapped Infinite Wave Envelope Elements, Walter Eversman, Indranil Danda Roy

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Variable order mapped infinite wave envelope elements are developed for finite element modeling of acoustic radiation in a uniformly moving medium. These elements can be used outside of the near field as a non-reflecting boundary condition for computations on an infinite domain in which a radiating body is immersed in a moving medium. Mapped infinite wave envelope elements provide a boundary condition equivalent to stiffness, mass, and damping matrices appended to the inner mesh. A demonstration of the characteristics of the mapped infinite wave envelope elements is given in the context of acoustic radiation from a turbofan inlet for which …

A New Technique For Estimating Confidence Intervals On Dea Efficiency Estimates, Janice Forrester, Timothy R. Anderson

Engineering and Technology Management Faculty Publications and Presentations

A new approach to chance constrained DEA is described and experimental results are given for calculating a confidence band for the estimated production function. This allows an interval containing the most likely production function, to be specified with a predetermined level of confidence.

Using Data Envelopment Analysis For Evaluating Alternative Software Development Process Configurations, Timothy R. Anderson, Peter K. Ghavami

Engineering and Technology Management Faculty Publications and Presentations

Summary form only given as follows. The goal of achieving better software depends on improvements in software development processes. This paper provides a nonparametric, quantitative methodology for evaluating alternative software development process configurations as a tool for process improvement. The methodology uses data envelopment analysis (DEA) for comparing the impact of varying degrees of software inspection on project schedule, cost and quality. Since every phase of the development process can be inspected at varying levels, a large number of process combinations become possible. Thus a manager's job to compare and select an efficient process configuration can become tedious. This is …

A Comparison Of Efficiency Measurement Using Data Envelopment Analysis And Regression In The Utility Industry, Janice Forrester, Timothy R. Anderson

Engineering and Technology Management Faculty Publications and Presentations

It is the intent of this paper to discuss the theoretical differences between the manner in which regression and data envelopment analysis (DEA) separate variation into that which is caused by noise and that caused by inefficiency. It examines the empirical results of independent studies, one that used regression and one that used DEA. The studies were performed one year apart by independent teams using the same data and responding to the same questions. Both studies focus on monitoring the efficiency of the electric utility providers in light of deregulation

Excitation Of The High-Q-Factor Whispering Gallery Modes In The Hemispherical Dielectric Resonator With The Cylinder Shield, Sergey Kharkovsky, V. V. Kutuzov, A. E. Kogut

Electrical and Computer Engineering Faculty Research & Creative Works

A hollow metal cylinder with a semicircle in the base is used as the shield of a hemispherical dielectric resonator with whispering gallery (WG) modes. It is shown that the spectrum of the WG modes of this resonator is clearer than the spectrum of a similar resonator with a hemispherical shield. It is determined that the high-Q-factor WG modes are excited in the proposed resonator by the coupling slot on the mirror. Their fields are localized in the dielectric. The frequency dependence of the Q-factor value is measured. A good conformity of this experimental dependence with the analytic dependence is …

Hardware-Software Co-Verification In An Undergraduate Laboratory, Hardy J. Pottinger, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

Skills in hardware-software co-design are quickly becoming critical to product development in high-technology computer industries. Systems-on-silicon typically include a considerable amount of software as well as custom hardware and are increasingly difficult to develop using traditional techniques. To satisfy a growing demand in industry, students in electrical Engineering; computer Engineering; and computer science should be introduced to concepts of hardware-software co-design at the undergraduate level. This paper examines a new laboratory at the University of Missouri-Rolla in which students in Electrical and Computer Engineering are exposed to modern system design concepts through the use of hardware-software co-simulation. Key tools used …

Predictive Head Tracking For Virtual Reality, Donald C. Wunsch, Emad W. Saad, T. P. Caudell

Electrical and Computer Engineering Faculty Research & Creative Works

In virtual reality (VR), head movement is tracked through inertial and optical sensors. Computation and communication times result in delays between measurements and updating of the new frame in the head mounted display(HMD). These delays result in problems, including motion sickness. We use recurrent and time delay neural networks to predict the head location and use it to calculate the new frame. A predictability analysis is used in designing the prediction system

Double-Talk Robust Fast Converging Algorithms For Network Echo Cancellation, T. Gansler, Steven L. Grant, J. Benesty, M. M. Sondhi

Electrical and Computer Engineering Faculty Research & Creative Works

Echo cancelers which cover longer impulse responses (greater than or equal to 64 ms) are desirable. Long responses create a need for more rapidly converging algorithms in order to meet the specifications for network echo cancelers devised by the ITU (International Telecommunication Union). In general, faster convergence implies a higher sensitivity to near-end disturbances, especially "double-talk". Recently, a fast converging algorithm called proportionate NLMS (normalized least mean squares) algorithm (PNLMS) has been proposed. This algorithm exploits the sparseness of the echo path. In this paper we propose a method for making the PNLMS algorithm more robust against double-talk. The slower …

Efficient Training Techniques For Classification With Vast Input Space, Donald C. Wunsch, Emad W. Saad, J. J. Choi, J. L. Vian

Electrical and Computer Engineering Faculty Research & Creative Works

Strategies to efficiently train a neural network for an aerospace problem with a large multidimensional input space are developed and demonstrated. The neural network provides classification for over 100,000,000 data points. A query-based strategy is used that initiates training using a small input set, and then augments the set in multiple stages to include important data around the network decision boundary. Neural network inversion and oracle query are used to generate the additional data, jitter is added to the query data to improve the results, and an extended Kalman filter algorithm is used for training. A causality index is discussed …

Implementation Of An Adaptive Neural Network Identifier For Effective Control Of Turbogenerators, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes an on-line identification technique for modelling a turbogenerator system. The dynamics of a single turbogenerator infinite bus system are modelled using an adaptive artificial neural network identifier (AANNI) based on continual online training (COT). This paper goes further to show that multilayered perceptrons with deviation signals as inputs and outputs trained using the standard backpropagation algorithm retain past learned information despite COT. Simulation and practical results are presented.

Integrating Power Engineering Topics And Applications In Non-Power Courses, S. Legowski, Badrul H. Chowdhury, J. J. Cupal, R. G. Jacquot, B. J. W. Pierre, A. H. M. S. Ula, B. M. Wilamowski

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates integrating power engineering material over the breadth of an electrical engineering curriculum. Electrical engineering curricula have a large number of required courses and many subareas for students to study. By introducing power concepts in a variety of courses, students may be motivated to take additional courses in the power area and are better prepared for the diverse background which will be required of them as practising power engineers. The important interrelationships between subareas of electrical engineering are better understood by students when cross discipline applications are discussed. This paper describes the introduction of power concepts and applications …

Reproduction Of Spectrum Envelope Of Microwave Wideband Noise And Detection A Narrowband Signal In It, Marina Koledintseva, Alexander A. Kitaytsev, V. A. Konkin

Electrical and Computer Engineering Faculty Research & Creative Works

A method of adequate visual microwave wide-band intense noise envelope reproduction in wide frequency range (several octaves), power parameters measurement and detection of a narrow-band signal with unknown frequency and power against a background of noise is presented. It is based on application of nonheterodyne gyromagnetic converter, operating in two regimes: resonance detection and cross-multiplication. Operation of the two-channel measurer of spectrum power density combining the mentioned functions is discussed

Speaker Identification Using A Combination Of Different Parameters As Feature Inputs To An Artificial Neural Network Classifier, Viresh Moonasar, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a technique using artificial neural networks (ANNs) for speaker identification that results in a better success rate compared to other techniques. The technique used in this paper uses both power spectral densities (PSDs) and linear prediction coefficients (LPCs) as feature inputs to a self organizing feature map to achieve a better identification performance. Results for speaker identification with different methods are presented and compared.

A Continually Online Trained Artificial Neural Network Identifier For A Turbogenerator, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of modern power systems highlights the need for advanced modelling techniques for effective control of power systems. This paper presents results of simulation and practical studies carried out on identifying the dynamics of a single turbogenerator connected to an infinite bus through a short transmission line, using a continually online trained (COT) artificial neural network (ANN).

A Robust Artificial Neural Network Controller For A Turbogenerator When Line Configuration Changes, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a robust controller for a turbogenerator. The robust controller is an artificial neural network (ANN) that is trained offline on a family of ANN models of the turbogenerator. This ANN controller augments/replaces the traditional automatic voltage controller (AVR) and the turbine governor of the generator. Simulation results are presented to show that the ANN controller is robust when the transmission line configuration changes.

Application Of Composite Gyromagnetic Materials For Absorbing Radiation Produced By Microwave Oven, Marina Koledintseva, Alexander A. Kitaytsev, V. A. Konkin, V. P. Cheparin, Andrey A. Shinkov

Electrical and Computer Engineering Faculty Research & Creative Works

Composite gyromagnetic radioabsorbing material (RAM) on the basis of polycrystalline hexagonal ferrites is elaborated for the suppression of unwanted radiation produced by microwave ovens (MWO). Results of laboratory investigation of this material application in the MWO having a magnetron source of microwave radiation are represented.

Environmental Performance Analysis Of Solid Freedom Fabrication Processes, Yanchun Luo, Zhiming Ji, Ming-Chuan Leu, R. J. Caudill

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a method for analyzing the environmental performance of solid freeform fabrication (SFF) processes. In this method, each process is divided into life phases. Environmental effects of every process phase are then analyzed and evaluated based on the environmental and resource management data. These effects are combined to obtain the environmental performance of the process. The analysis of the environmental performance of SFF processes considers the characteristics of SFF technology, includes material, energy consumption, processes wastes, and disposal. Case studies for three typical SFF processes: stereolithography (SL); selective laser sintering (SLS); and fused deposition modeling (FDM) are presented …

Frequency Domain Robustness Analysis Of Hopfield And Modified Hopfield Neural Networks, Jie Shen, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A variant of Hopfield neural network, called the modified Hopfield network, is formulated in this study. This class of networks consists of parallel recurrent networks which have variable dimensions that can be changed to fit the problem under consideration. It has a structure to implement an inverse transformation that is essential for embedding optimal control gain sequences. Equilibrium solutions of this network are discussed. The robustness of this network and the classical Hopfield network are carried out in the frequency domain using describing functions

Stability Analysis Of Nonlinear Machining Force Controllers, Robert G. Landers, Yen-Wen Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Model parameters vary significantly during a normal operation, thus, adaptive techniques have predominately been used. However, model-based techniques that carefully account for changes in the force process have again been examined due to the reduced complexity afforded by such techniques. In this paper, the effect of model parameter variations on the closed-loop stability for two model-based force controllers is examined. It was found that the stability boundary in the process parameter space can be exactly determined for force control systems designed for static force processes. For force control systems designed for first-order force processes, it was found that the stability …

Functional Interdependence And Product Similarity Based On Customer Needs, Daniel A. Mcadams, Robert B. Stone, Kristin L. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, related product functions are determined for a group of approximately 70 consumer products. Using customer need data, a new matrix approach is introduced to identify these relationships. Techniques are then created for determining product similarity. These techniques are clarified and validated through three case studies, including beverage brewers and material-removal products. The results of these case studies are argued to have significant impact on design-by-analogy procedures, benchmarking methods, mass customization strategies and modular design. The paper concludes with a discussion of applications and related procedures for product development.