Digital Commons Network^™

Study Of Automotive Hydromount Mechanism, Min Lu

Dissertations

The hydromount mechanism is studied. It was determined that the dynamic characteristics of the hydromounts are related to the rubber static stiffness, rubber damping coefficient, volumetric stiffness, and effectiveness of the oscillating fluid in the inertia track. At high frequencies the motion of the fluid in the inertia track diminishes so that its effect is negligible and may be ignored. It is also concluded that the rubber damping has a minimal effect on the hydromount dynamic properties and may be neglected. The maximum loss angle, which corresponds to the maximum damping coefficient of the hydromount, occurs near the inertia track …

A Substructuring Technique With Application To Spot Weld Placement Design, Yang Wang

Mechanical & Aerospace Engineering Theses & Dissertations

It is quite common in the industry to use various interface methods, such as welding, fasteners, bolts, adhesive bonding, etc., to join substructures together. The quality of the assembled structure is directly related to the type of the interface methods used in the manufacturing process. Thus, it is important to include the interface conditions as part of design variables in any design process. To this end, this work develops a reanalysis method that can efficiently analyze structures with variations on the interface conditions. This reanalysis method is based upon a new two-step substructuring technique. The first step performs substructural level …

Spice-Based Heat Transport Model For Non-Intrusive Thermal Diagnostic Applications, Michael Stelzer

Electrical & Computer Engineering Theses & Dissertations

Nondestructive material testing and diagnostics play an important role in reliability analysis, component wear-out testing, life-cycle estimates, and safety inspections. Of the several techniques available for nondestructive inspections, thermal analysis has been chosen to be the focus of this thesis research. An equivalence between the system of equations for the heat flow problem, and the variables of circuit theory suggests that an electrical model can be constructed to represent the actual thermal system. This electrical model is constructed based upon a finite difference discretization of the heat flow equation. Using these associations a basic one-dimensional electrical model has been constructed …

Development And Testing Of A Cfd-Based Optimization System For Axially Symmetric Rocket Nozzles, John-Paul Shebalin

Mechanical & Aerospace Engineering Theses & Dissertations

A software system has been developed to optimize rocket nozzle shapes for maximizing their performance. It has been established in the literature that one can use computer-based optimization with the parabolized Navier-Stokes equations to optimize the dimensions of low Reynolds number rocket nozzles-micronozzles. The Nozzle Optimization System described herein uses the full Navier-Stokes equations to optimize any axially symmetric rocket nozzle for which a converged solution can be obtained.

Four nozzles are optimized using this system-conical and contoured micronozzles and conical and contoured Space Transportation System(STS)-class nozzles. The optimum cone angle (O_cone) for the conical micronozzle was …

Control And Characterization Of Line-Addressable Micromirror Arrays, Harris J. Hall

Theses and Dissertations

This research involved the design and implementation of a complete line-addressable control system for a 32x32 electrostatic piston-actuated micromirror array device. Line addressing reduces the number of control lines from N² to 2N making it possible to design larger arrays and arrays with smaller element sizes. The system utilizes the electromechanical bi-stability of individual elements to bold arbitrary bi-stable phase patterns. The control system applies pulse width modulated (PWM) signals to the rows and columns of the micromirror array. Three modes of operation were conceived and built into the system. The first was the traditional signal scheme which requires …

Bistable Operation Of A Two-Section 1.3-Mm Inas Quantum Dot Laser—Absorption Saturation And The Quantum Confined Stark Effect, Xiaodong Huang, A. Stintz, Hua Li, Audra Rice, G. T. Liu, L.F. Lester, Julian Cheng, K.J. Malloy

Faculty Publications

Room temperature, continuous-wave bistability was observed in oxide-confined, two-section, 1.3- m quantum-dot (QD) lasers with an integrated intracavity quantum-dot saturable absorber. The origin of the hysteresis and bistability were shown to be due to the nonlinear saturation of the QD absorption and the electroabsorption induced by the quantum confined Stark effect.

Effects Of Concentration And Temperature On The Coupled Heat And Mass Transport In Liquid Mixtures, Yaşar Demirel, Stanley I. Sandler

Papers in Thermal Mechanics

Using published experimental data on the thermal conductivity, mutual diffusivity, and heats of transport, the degree of coupling between heat and mass flows has been calculated for binary and ternary nonideal liquid mixtures. The binary mixtures consist of two types: the first is six systems of six-to-eight-carbon straight and branched chain alkanes in chloroform and in carbon tetrachloride; and the second is mixtures of carbon tetrachloride with benzene, toluene, 2-propanone, n-hexane, and 11-octane. The ternary mixture considered is toluene-chlorobenzene-bromobenzene. The published data are available at 35°C, 30°C, and 35°C and ambient pressure. Using the linear nonequilibi-ium thermodynainics (LNET) and the …

Numerical Stimulation Of Stress-Induced Crystallization Of Injection Molded Semicrystalline Thermoplastics, Jianxin Guo

Dissertations

Injection molded semicrystalline plastic products exhibit variable morphology along their thickness directions. The processing conditions have a significant effect on the crystallinity distribution in the final parts. However, because of the lack of sound theoretical models for stress-induced crystallization kinetics in thermoplastics, simulations of the injection molding process of semicrystalline plastics with the consideration of stress-induced crystallization have been scarce.

A stress-induced crystallization model for semicrystalline plastics is proposed based on the theory that stress induced orientation of polymer chains increase the melting temperature of the plastics, and hence, the supercooling which is the driving force for crystallization. By assuming …

Numerical Modeling And Optimization Of Waterjet Based Surface Decontamination, Konstantin Babets

Dissertations

The mission of this study is to investigate the high-pressure waterjet based surface decontamination. Our specific objective is to develop a practical procedure for selection of process conditions at given constraints and available knowledge. This investigation is expected to improve information processing in the course of material decontamination and assist in the implementation of the waterjet decontamination technology into practice. The development of a realistic procedure for processing of a chaotic and non-accurate information constitutes the main accomplishment of this study.

The research involved acquisition of representative information about removal of brittle, elastic and viscous deposits. As a result an …

Electro-Magnetic Control Of Cylinder Wake, Zhihua Chen

Dissertations

The objective of this dissertation is to develop open and closed-loop control algorithms for manipulating wake flows past a solid cylinder in an electrically low-conducting fluid (e.g. seawater). The intent is to avoid both vortex shedding and flow separation from the body. It is desired to reduce the mean drag significantly and prevent the lift from becoming non-zero at all times. This is achieved through the introduction of a Lorentz force in the azimuthal direction generated by an array of permanent magnets and electrodes located on the solid structure. The array of actuators offers the advantage of making the Lorentz …

Kinematic Synthesis Of Adjustable Spatial Four And Five-Bar Mechanisms For Finite And Multiply Separated Positions, Kevin Russell

Dissertations

Although spatial mechanisms are more general in structure than planar mechanisms, their applications are few due to the limited number of practical design tools and the complexity of those available. It is in fact the task of the future to develop effective, but practical design tools for spatial mechanisms.

This research presents several new methods for synthesizing adjustable spatial mechanisms. The first method involves the kinematic synthesis of spatial mechanisms for multiphase motion generation. Using this method, spatial four and five-bar mechanisms can be synthesized to achieve different phases of prescribed rigid body positions. The theory of this approach has …

Numerical Studies Of Newtonian And Viscoelastic Fluids, Felix J. Alcocer

Dissertations

The direct numerical simulation (DNS) approach is used to understand the flow behavior of Newtonian and viscoelastic fluids in porous materials, four-to-one contraction and the flow of a Newtonian fluid past an airfoil.

In simulations the viscoelastic fluid is modeled by the finitely extensible nonlinear elastic (FENE) dumbbell and Oldroyd-B models. The finite element method (FEM) is used to discretize the flow domain. The DNS results show that the permeability of a periodic porous medium depends on the wavelength used for arranging particles in the direction of flow. Specifically, it is shown that for a given particle size and porosity …

Report Of The State Nuclear Safety Advisor Submitted To The Governor And 120th Legislature As Of January 15, 2001, Paula M. Craighead

Maine Collection

Report of the State Nuclear Safety Advisor submitted to the Governor and 120th Legislature As of January 15, 2001

Paula M. Craighead, State Nuclear Safety Advisor, Executive Department, Maine State Planning Office, Augusta, Maine, 2001.

Contents: Introduction and Executive Summary / I. Maine Yankee Decommissioning / II. Portsmouth Naval Shipyard (PNS) / III. Low-Level Radioactive Waste (LLRW) / IV. High Level Radioactive Waste / V. Transport Routes and Safety Response / VI. Shipments / VII. Status of Federal and State Legal and Administrative Proceedings / References and Resources / Glossary

Basic Engineering Science --- A Systems, Accounting, And Modeling Approach, Donald E. Richards

Faculty Publications - Mechanical Engineering

This textbook is based on a different paradigm for organizing an engineering science core --- a systems, accounting and modeling approach --- that emphasizes the common, underlying concepts of engineering science. Although this approach is not new, as most graduate students have been struck by this idea sometime during their graduate education, its use as the organizing principle for an undergraduate curriculum is new. By focusing on the underlying concepts and stressing the similarities between subjects that are often perceived by students (and taught by faculty) as unconnected topics, this approach provides engineering students a foundational framework for recognizing and …

Task Specific Uncertainty In Coordinate Measurement, R. G. Wilhelm, R. Hocken, H. Schwenke

Department of Mechanical and Materials Engineering: Faculty Publications

Task specific uncertainty is the measurement uncertainty associated with the measurement of a specific feature using a specific measurement plan. This paper surveys techniques developed to model and estimate task specific uncertainty for coordinate measuring systems, primarily coordinate measuring machines using contacting probes. Sources of uncertainty are also reviewed.

Languages For Engineering Design: Empirical Constructs For Representing Objects And Articulating Processes, Clive L. Dym, Philip Brey

All HMC Faculty Publications and Research

Design knowledge incorporates knowledge and information about designed objects and their attributes, as well as about methods and means for undertaking the design process. Such design knowledge is articulated in several different representations or languages. This paper presents a typology of the languages of engineering design, emphasizing the representation of designed objects and the articulation and representation of the cognitive processes of design. Design languages include verbal or textual statements, drawings and graphics, formulas, and numbers. Still other design languages follow from computational styles. The languages of design and their computer-based implementations are empirical in origin, since observation reveals that …

Mathematical Modeling For Fabricating A Microstructure With A Pre-Specified Geometry Using Laser -Induced Chemical Vapor Deposition, Chaoyang Zhang

Doctoral Dissertations

Laser-induced chemical vapor deposition (LCVD) is an emerging new technique with many practical applications. To optimize the system for fabricating a microstructure with a pre-specified geometry in pyrolytic LCVD, a three-dimensional mathematical model is developed for predicting temperature distributions and laser dwell times across the substrate scanned by the laser beam. A microstructure is fabricated layer by layer, and for each layer the laser beam moves from one pixel to the next. The complicated correlations among temperature distribution, deposit growth rate, and laser dwell time are investigated. A purely heterogeneous reaction is assumed and any gas-phase transport is ignored.

A …

Meeting The Needs Of Industry: Development Of A Microcontroller Course For Mechanical Engineers, W. G. Culbreth

Mechanical Engineering Faculty Research

No abstract provided.

An Interactive Visual Environment For Scientific Problem Solving, Georg F. Mauer

Mechanical Engineering Faculty Research

No abstract provided.

Modeling, Fabrication, And Optimization Of Niobium Cavities: Phase I, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Niobium cavities are important parts of the integrated NC/SC high-power linacs. Over the years, researchers in several countries have tested various cavity shapes. They concluded that elliptically shaped cells and buffered chemical polishing produce good performance. The objective of the proposed research is to maximize the performance of the niobium cavities through studying multipacting, studying the effect of chemical etching on the surface roughness, and redesigning the cavities.

The US Congress has recently authorized exploring an alternative way to deal with spent nuclear fuel: Accelerator Transmuting of Waste (ATW). In this approach, a particle accelerator produces protons that react with …

Nebraska Summary 354: Agco Dt200 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1790: 9300 T 24 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1797: Case Ih Stx 325/New Holland Tj 325 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1796: Case Ih Stx 275/New Holland Tj 275 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1794: White 8710 Also Agco Allis 9775 (Cummins Engine) Also Agco Dt200, 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 …

Tractor Test 1780a: White 8785, 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 …

Test 1792: Massey Ferguson 2210 Diesel 15-Speed, 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 …

Nebraska Summary 389: Fendt 920 Vario Diesel, 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 …

Nebraska Summary 390: Fendt 924 Vario Diesel, 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 …

Nebraska Summary 391: Fendt 926 Vario Diesel, 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 …