Engineering Commons^™

Closed-Loop Identification Of Unstable Systems In Time And Frequency Domains, Hyun Chang Lee

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation presents closed-loop identification algorithms of an unstable system in the time and frequency domains. In the time domain, the projection filter, which is a linear transformation which projects (transforms) a finite number of input-output data of a system into its current space, is used to relate the state-space model with a finite difference model. The method developed can take into account the effects of process noise as well as measurement noise and identify open-loop systems with unknown feedback dynamics in the closed-loop operation. Then the recursive relations between Markov parameters and the ARX model are derived to identify …

Development Of A Knowledge-Based System For Generating Process Plans Using Group Technology: A Study For Norfolk Naval Shipyard, William P. Keene Jr.

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to study and analyze the Norfolk Naval Shipyard's manufacturing methods of determining part families and generating part process plans for parts in the machine shop. A knowledge-based decision support system was designed based on knowledge acquired from machinist experts and documented sources of the Norfolk Naval Shipyard. The system interprets specific part information provided by the user, categorizes parts into part families and generates process plans to manufacture the parts. The system was evaluated and tested for parts provided by Norfolk Naval Shipyard.

Component Mode Synthesis-Based Design Methodology For Structural Modification And Synthesis, Venkateshwarlu Maroju

Mechanical & Aerospace Engineering Theses & Dissertations

In this work, structural modification and synthesis techniques based on component mode synthesis are presented. The component mode synthesis method formulates the eigenvalue equation of an entire structure in terms of the vibration characteristics of individual components in the assembly. Through this functional relationship, the individual components are successfully treated as the design entities in the proposed methodology. Unlike conventional design modification techniques that can only treat the properties of the finite elements as the design variables, this technique uses the vibration and static responses of the individual components as the design entities. The sensitivity derivatives of the global responses …

Tractor Test Museum Committee Meeting March 17th, 1995, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Camp Creek Threshers Foundation Funds 1915 Ford tractor restoration

Fiber Optic Detector And Depth Sensor And Method For Doing Same, Lawrence W. Evers, Kenneth J. Jackson

Michigan Tech Patents

A fiber optic sensor for determining the presence and/or measuring the depth of a first substance capable of transmitting light. The fiber optic sensor includes a plurality of light receiving fibers, a plurality of light transmitting fibers surrounding the light receiving fibers and structure for refracting light from the light transmitting fibers at a predetermined angle for total internal reflection of the light from an interface of the first substance with a second substance.

Apparatus For Rotational Motion, Said Shakerin

All Faculty Articles - School of Engineering and Computer Science

No abstract provided.

Wiping Out Tall Weeds, Brad Rayner

Journal of the Department of Agriculture, Western Australia, Series 4

Control of weeds is an on-going battle for farmers, with many weapons becoming increasingly expensive. A refreshing exception to this trend is the blanket wiper, a cheap but effective meens of applying herbicides to taller weeds in pasture. Brad Rayner explains how it works.

Observation Of Laser Ignition And Combustion Of Pulverized Coals, John C. Chen, Masayuki Taniguchi, Kazuyuki Ito

Mechanical Engineering

Direct observation of pulsed-laser ignition and combustion of pulverized coals with a high speed video has been made. A dilute stream of particles was dropped into a laminar, upward-flow wind tunnel with a quartz test section. The gas stream was not preheated. A single pulse from a Nd:YAG laser was focused through the tunnel and ignited several particles. The transparent test section and cool walls allowed for optical detection of the reaction sequence. The ignition and combustion behaviours of amorphous carbon spheres and an anthracite were as expected for heterogeneous ignition and reaction. Surprisingly, the reaction of a high volatile …

Excess Heat Capacity Surfaces For Water-Alkanol Mixtures By The Uniquac Model, Yaşar Demirel, Halime Ö. Paksoy

Papers in Physical Chemistry

Hydroorganic mixtures are industrial solvents that can serve as media to solubilize either water in hydrocarbon or a hydrophobic substance in water. In many cases the solubilizing capability is obtained via a homogeneous complex aqueous mixtures containing an alcohol. Since excess heat capacity C_P^E, is very sensitive to structural changes in mixtures, concentration and temperature dependence of C_P^E have been calculated by using the UNIQUAC model for the mixtures methanol(l)-water(%, ethanol(l)-water(2), and l-propanol(l)-water(2). The temperature-dependent parameters of the model estimated directly from C_P^E data at more than one different isotherm are used in …

Optimization Of Expanded Polypropylene Foam Coring To Improve Bumper Foam Core Energy Absorbing Capability, Gregory Frederick, Gregory A. Kaepp, Conrad M. Kudelko, Peter J. Schuster, Friedrich Domas, Udo G. Haardt, Werner Lenz

Mechanical Engineering

To design a cost, weight, and energy efficient bumper foam energy absorber, it is important to consider optimizing the shape of coring employed in the design of the system. In this paper, a number of foam coring patterns are studied by both empirical and analytical methods. The size and shape of proposed core designs are studied in detail with consideration given to several different densities of expanded polypropylene (EPP) foam. Using the finite element method of structural analysis, it is possible to have an inside look at the stress distribution during deformation of foam structures. An optimization study using the …

Otter: A Testbed Submersible For Robotics Research, Tim Mclain, H H. Wang, R L. Marks, S D. Fleischer, D W. Miles, G A. Sapilewski, S M. Rock, M J. Lee, R C. Burton

Faculty Publications

Untethered, unmanned submersibles (UUSs) have the potential of becoming useful tools in nuclear reactor inspection and repair and waste-site cleanup and survey, in addition to subsea exploration. Classical "hand-in-glove" control methods used currently by tethered, remotely-operated vehicles (ROVs) are unsuitable for UUS systems which have, at best, limited communications. The Stanford Aerospace Robotics Laboratory (ARL) has joined with the Monterey Bay Aquarium Research Institute (MBARI) in a program to develop new methods of controlling UUS systems.

As a part of this effort, a submersible testbed has been built to test and develop new technologies that will make UUSs useful tools …

A Petri-Net Based Methodology For Modeling, Simulation, And Control Of Flexible Manufacturing Systems, Venkatesh Kurapati

Dissertations

Global competition has made it necessary for manufacturers to introduce such advanced technologies as flexible and agile manufacturing, intelligent automation, and computer-integrated manufacturing. However, the application extent of these technologies varies from industry to industry and has met various degrees of success. One critical barrier leading to successful implementation of advanced manufacturing systems is the ever-increasing complexity in their modeling, analysis, simulation, and control. The purpose of this work is to introduce a set of Petri net-based tools and methods to address a variety of problems associated with the design and implementation of flexible manufacturing systems (FMSs). More specifically, this …

Robust Approach To Object Recognition Through Fuzzy Clustering And Hough Transform Based Methods, Tianxiong Fu

Dissertations

Object detection from two dimensional intensity images as well as three dimensional range images is considered. The emphasis is on the robust detection of shapes such as cylinders, spheres, cones, and planar surfaces, typically found in mechanical and manufacturing engineering applications. Based on the analyses of different HT methods, a novel method, called the Fast Randomized Hough Transform (FRHT) is proposed. The key idea of FRHT is to divide the original image into multiple regions and apply random sampling method to map data points in the image space into the parameter space or feature space, then obtain the parameters of …

Statistical And Finite Element Analysis Of The Effects Of Random Input Parameters On The Mechanical Characteristics Of Sheetmetal Forming Processes Using Quadrature Method, Yu Quan

Theses

In this thesis, the computer aided finite element analysis is implemented in the analysis of sheetmetal forming process. To rationalize the experimentation and analysis, the statistical method is introduced to study the variability of sheetmetal deformation process and final shape with respect to the variation of different parameters.

In Chapter 2, the basic characteristics and considerations of deep drawing operation is described with emphasis on the study of geometrical and physical variables of the forming process.

Chapter 3 discussed the three phases which are encountered in the computer aided finite element analysis. As a typical representative of professional finite element …

Design For Quality Manufacturability Analysis Of Missing/Misplaced Parts And Part Interference, Altaf Yusuf Tamboo

Theses

Design for Quality Manufacturability (DFQM) is an approach that addresses the issue of quality manufacturability (QM) - the likelihood that defects will occur during manufacture of a product in a standard plant. The DFQM methodology is based on the premise that defects found in assembled products are often influenced by some features of the design and/or assembly process (influencing factors). These influencing factors cause defects in the presence of certain error catalysts.

One of the influencing factors is geometrical features such as shape and symmetry. A classification scheme for part shape and symmetry is developed. This scheme is summarized in …

Design For Quality Manufacturability Analysis For Common Assembly Process, Suriyanarayanan Ramachandra

Theses

The globalization of market economy has precipitated a dramatic increase in competition necessitating the need for higher quality products at lower cost in shorter time periods. Shorter life cycles and proliferation of products has made companies integrate all the phases of manufacturing to bring about a superior design. Design for Quality Manufacturability (DFQM) provides a technique to invoke manufacturing and assembly considerations while designing a product. The DFQM architecture identifies factors consisting of several variables that are influenced by certain error catalysts to cause one or more specific defects. A methodology is suggested to identify and quantify these error catalysts …

Investigation Of Velocity Distribution Within High Speed Waterjet, Hong Cao

Theses

The aim of this research was to investigate velocity distribution within the water jet at different conditions of jet formation. The water jet (WJ) velocity was measured by the use of Laser Transit Anemometer (LTA) and statistical technique which improved the accuracy of the velocity determination.

The velocities were measured for different diameters of the sapphire nozzle under different water pressures at different axial stand off distances and radial distances across the jet. The experiments performed in this study enabled us to evaluate the effects and conditions of the water jet on the velocity distribution. The acquired results provide information …

Viscoelastic Effects On Parallel Flow Stability, Transition To Turbulence, And Turbulent Flow, Michael Garofalo

Theses

The classical two dimensional theory of stability of parallel flow is extended to viscoelastic fluids. How the elasticity of the fluid affects the point of stability and determines the point of transition to turbulence is analyzed. In addition the magnification of disturbances is elucidated. This study is based on a viscoelastic constitutive equation which has been successful in predicting the experimental trends of various unsteady high shear rate laminar flows. A viscoelastic stability equation which is an extension to the Orr-Sommerfeld equation for a Newtonian fluid is derived and solved for a flow between parallel plates superimposed by a two-dimensional …

Case Study Of Assembly Defects In Manufactured Products, Michael J. Withka

Theses

Design for Quality Manufacturability (DFQM) is a design tool that empowers engineers to create designs that are easily and effectively transformed into manufactured products. The goal of this methodology is to make designers aware of design characteristics that may lead to product defects during the assembly process. Acknowledging the possibility of these defects will enable the designer to institute design modifications early in the design phase. The benefits realized in this approach are a reduction in the number of defects in the finished product, reduced product cycle times, a reduction in monitoring costs and a reduction in time-to-market.

This thesis …

A Systematic Approach To Defense Diversification, Sathappan Venkatachalam

Theses

The decline in defense spending has resulted in defense dependent companies seeking new markets through re-designing existing products, developing new products and restructuring their businesses. Defense diversification is defined as the process of transitioning a defense company's core capabilities (technologies, products, services) into commercial and non-Department of Defense government markets. A combination of site visits and review of the literature on defense diversification demonstrates the need for diversifying companies to adopt a systematic approach.

A concurrent new product development/product redevelopment model is proposed, based on the principles of concurrent engineering. The model consists of an eight phase development cycle and …

Simulation Study Of Particle Tracking System, Prashant B. Patel

Theses

A particle tracking system is being developed in the Particle Technology Laboratory of the Mechanical Engineering Department, at NJIT, In this thesis, an attempt is made to understand the effect of various parameters on the errors in the computed position and orientation of the sphere being tracked. Simulation results for a single transmitter assembly as well as a three transmitter assembly with 6, 9 and 17 antennae are presented. The effects of the level of noise in the voltages on the solution for the single transmitter assembly and three transmitter assembly are discussed. The concept of virtual antenna is introduced …

Use Of Multiple Transmitters For 3-D Non-Intrusive Particle Tracking, Jitesh H. Agrawal

Theses

A method for non-intrusive tracking of a particle in 3-dimensional space, based on processing of signals emitted from a transmitter embedded in the particle, is being developed. This method uses a mathematical model, which predicts the induced signal in receivers present in the vicinity of flowing particle, and supporting numerical techniques. Specific application aspects related to improving the accuracy of this method are presented.

The focus here is the development of flexible software capable of processing information coming from multiple transmitters with known distinct spatial orientation. Implementation aspects of modified existing empirical corrections for improving model-reality agreement, and new techniques …

Development Of An Expert System To Facilitate A Pump Manufacturing/Warehouse Facility, Muhammad Mutahir Ghauri

Theses

The objective of this study is to evaluate the effectiveness of utilizing an expert system technology as it relates to manufacturing. It appears that our industries are still uncertain about this technology. In the first phase of this study, procedure for deployment of this technology is discussed. Secondly a knowledge-based expert system is developed, using a VP-Expert microcomputer shell. The system is made of three modules, inventory module, cost analysis module, and decision making module (for the selection of pumps).

A warehouse was selected for the analysis, which carries the finished product in the form of pumps. The quantities and …

Ultrasonic Detection Of A Plastic Hinge In Bolted Timber Connections, David Pollock, Donald A. Bender, Don E. Bray, James T P Yao

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Connections between structural members are critical elements that typically govern the performance of structural systems; hence, techniques for monitoring the condition of connections are needed to provide early warning of structural damage. Plastic hinge formation in fasteners frequently occurs in timber connections when the yield capacity is exceeded. An innovative pulse echo testing technique was developed for detecting the formation of a plastic hinge in bolted timber connections and estimating the associated magnitude of connection displacement. A shift in overall signal centroid proved to be the best flTedictor of plastic hinge formation, with a coefficient of determination (R2) of 0.9. …

Test 1688: John Deere 8100 Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE

General

Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure.

The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Development Of A Desuperheater Rating Method For Energy Code Calculations, Tim Merrigan

Retrospective Theses and Dissertations

The purpose of this project was to develop a rating method for desuperheater water heaters – heat exchangers that remove superheat from the refrigerant in an air conditioner’s compressor discharge line. The project methodology was to first determine the overall heat transfer coefficient-area product (UA) of the heat exchanger for three basic types of desuperheaters. Both heat transfer analysis and the laboratory performance data indicated that the number of transfer units (NTU) for each heat exchanger was relatively independent of the operating conditions for a properly-charged air conditioner with a single-speed compressor and a desuperheater with a single-speed circulating pump. …

Fuzzy Logic In Restructurable Flight Control Systems, S. N. Balakrishnan, H. S. Ho

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a fuzzy logic controller (FLC) is proposed for restructurable flight control systems. The role of the FLC is to stabilize the aircraft upon a fault occurrence. The FLC derives pitch/roll/yaw controls from a generic knowledge base characterized by 49 if-then rules. A linearized model representative of a modern jet fighter provides the basis for the numerical simulation. Simulated faults include various degrees of surface loss at the right stabilator, combined with reduced ailerons and rudder control power. The FLC accomplishes the stabilization task under test conditions without any knowledge of the system parameters. The numerical results demonstrate …

Intercomparison Between Commercial Condensation Nucleus Counters And An Alternating Temperature Gradient Cloud Chamber, Darryl J. Alofs, C. K. Lutrus, Donald E. Hagen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Three Commercial CNC Counters (TSI Models 3010, 3022A, and 3025A) Are Compared with an Alternating Temperature Gradient Cloud Chamber (ALGR). Electrically Size Classified Aerosols of Sodium Chloride and Silver Are Used. Diffusional Losses within the ALGR Are Much Larger Than for the TSI Instruments: Therefore the ALGR Concentrations Are Corrected for Internal Diffusional Losses, But the TSI Instruments Are Not. the Particle Size Range Tested is 4–90 Nm. for Sodium Chloride, the TSI Concentrations Agreed Fairly Well with the Corrected ALGR at Larger Sizes, and Were Below the Corrected ALGR at Smaller Sizes. the Electrical Aerosol Classifier (EAC) Setting at …

Using Matlab To Illustrate The 'Phenomenon Of Aliasing', Sol Neeman, Ph.D.

Engineering Studies Faculty Publications and Creative Works

The phenomenon of aliasing is important when sampling analog signals. In cases where the signal is bandlimited, one can avoid aliasing by ensuring that the sampling rate is higher than the Nyquist rate . But in cases where the signal is not bandlimited , aliasing is unavoidable if the signal is not filtered before it is sampled. It is then crucial to understand the phenomenon in order to estimate the distortion generated when the signal is reconstructed from its samples. Using the software package MATLAB by MathWorks, Inc ., two examples are presented. The first is a pure sinusoid which …

Nebraska Summary: S195 Caterpillar Challenger 45, 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 …