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2001

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Articles 1 - 30 of 158

Full-Text Articles in Mechanical Engineering

Numerical Simulation Of Mechanofusion System For Dry Particle Coating Process, Wenliang Chen Dec 2001

Numerical Simulation Of Mechanofusion System For Dry Particle Coating Process, Wenliang Chen

Dissertations

A numerical simulation of the Meclianofusion device for dry particle coating is carried out using Discrete Element Method (DEM) technique. In dry particle coating, tiny sub-micron guest particles are coated onto larger micron sized host particles by using mechanical forces, which the Mechanofusion device provides. It consists of a rotating cylindrical chamber that contains the powder mixture, a stationary inner piece (which has a cylindrical surface at the end), and a fixed scraper blade, which prevents powder from caking against the chamber wall. The simulation studies are performed on two scales: system scale to investigate the particle-particle and particle system ...


Experimental And Numerical Study Of Flow Characteristics And Segregation In Flow Enhanced Systems, Gregory James Dec 2001

Experimental And Numerical Study Of Flow Characteristics And Segregation In Flow Enhanced Systems, Gregory James

Dissertations

In the study of granular materials, two major topics of importance are powder flow enhancement mechanisms and the flow characterization. This dissertation is involved with both of these topics. With respect to the powder flow enhancement, this study involves investigation of two types of flow enhancement methods. The first flow enhancement method examined is a novel method called the Magnetically Assisted Powder Flow (MAPF) method. In the MAPF, small magnetic particles and powders are placed in a test hopper. A mesh is placed at the bottom of the hopper to hold the magnetic particles while the powder is discharged through ...


Computation And Control Of Flow-Induced Noise Behind A Circular Cylinder Using An Acoustic Analogy Approach, Sirivit Taechajedcadarungsri Dec 2001

Computation And Control Of Flow-Induced Noise Behind A Circular Cylinder Using An Acoustic Analogy Approach, Sirivit Taechajedcadarungsri

Dissertations

The computational aeroacoustics (CAA) research, which focuses on predicting acoustics by means of advanced numerical techniques, has recently gained a great deal of progress. In most applications, the prediction of both the sound source and its far-field propagation is necessary as required by regulations. Recently, powerful computers and reliable algorithms have allowed the prediction of far-field noise through the use of Computational Fluid Dynamics (CFD) data as near-field sound sources. One of the most useful analytical methods, used for the computation of noise, is Lighthill's acoustic analogy. The latter will be used in the present study.

Lighthill's acoustic ...


Horses Damp The Spring In Their Step, Alan M. Wilson, M. Polly Mcguigan, Anne Su, Antonie J. Van Den Bogert Dec 2001

Horses Damp The Spring In Their Step, Alan M. Wilson, M. Polly Mcguigan, Anne Su, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The muscular work of galloping in horses is halved by storing and returning elastic strain energy in spring-like muscle–tendon units1, 2.These make the legs act like a child's pogo stick that is tuned to stretch and recoil at 2.5 strides per second. This mechanism is optimized by unique musculoskeletal adaptations: the digital flexor muscles have extremely short fibres and significant passive properties, whereas the tendons are very long and span several joints3, 4. Length change occurs by a stretching of the spring-like digital flexor tendons rather than through energetically expensive length changes in the ...


Hybrid Transient-Parametric Method And System To Distinguish And Analyze Sources Of Acoustic Emission For Nondestructive Inspection And Structural, Health Monitoring, Yuris Dzenis Dec 2001

Hybrid Transient-Parametric Method And System To Distinguish And Analyze Sources Of Acoustic Emission For Nondestructive Inspection And Structural, Health Monitoring, Yuris Dzenis

Mechanical & Materials Engineering Faculty Publications

A nondestructive evaluation (NDE) technique for inspecting or health monitoring of Structures and/or Specimens by analyzing acoustic emission (AE) signals emitted by the Structures and/or specimens. The method and System ana lyzes acoustic emission (AE) signals emitted by structures and/or Specimens. AE Signals emitted by the Structures and/or Specimens are parametrically filtered as a function of parametric filters corresponding to characteristic waveforms of transient AE classes of predefined AE signals. In para metric analysis, the filtering may be pre- or post-recording. In transient AE analysis, the filtering may be prior to transient recording of the transient ...


Modeling And Control Of Formations Of Nonholonomic Mobile Robots, Jaydev P. Desai, James P. Ostrowski, R. Vijay Kumar Dec 2001

Modeling And Control Of Formations Of Nonholonomic Mobile Robots, Jaydev P. Desai, James P. Ostrowski, R. Vijay Kumar

Departmental Papers (MEAM)

This paper addresses the control of a team of nonholonomic mobile robots navigating in a terrain with obstacles while maintaining a desired formation and changing formations when required, using graph theory.We model the team as a triple, (g, r, H), consisting of a group element g that describes the gross position of the lead robot, a set of shape variables r that describe the relative positions of robots, and a control graph H that describes the behaviors of the robots in the formation. Our framework enables the representation and enumeration of possible control graphs and the coordination of transitions ...


Modeling And Control Of Formations Of Nonholonomic Mobile Robots, Jaydev P. Desai, James P. Ostrowski, Vijay Kumar Dec 2001

Modeling And Control Of Formations Of Nonholonomic Mobile Robots, Jaydev P. Desai, James P. Ostrowski, Vijay Kumar

Departmental Papers (MEAM)

This paper addresses the control of a team of nonholonomic mobile robots navigating in a terrain with obstacles while maintaining a desired formation and changing formations when required, using graph theory.We model the team as a triple, (g, r, H), consisting of a group element that describes the gross position of the lead robot, a set of shape variables g that describe the relative positions of robots, and a control graph H that describes the behaviors of the robots in the formation. Our framework enables the representation and enumeration of possible control graphs and the coordination of transitions between ...


A Theory Of Volumetric Growth For Compressible Elastic Biological Materials, Stephen M. Klisch, Timothy J. Van Dyke, Anne Hoger Dec 2001

A Theory Of Volumetric Growth For Compressible Elastic Biological Materials, Stephen M. Klisch, Timothy J. Van Dyke, Anne Hoger

Mechanical Engineering

A general theory of volumetric growth for compressible elastic materials is presented. The authors derive a complete set of governing equations in the present configuration for an elastic material undergoing a continuous growth process. In particular, they obtain two constitutive restrictions from a work-energy principle. First, the authors show that a growing elastic material behaves as a Green-elastic material. Second, they obtain an expression that relates the stress power due to growth to the rate of energy change due to growth. Then, the governing equations for a small increment of growth are derived from the more general theory. The equations ...


Uwit: Underwater Image Toolbox And Mosaicking In Matlab, R. Eustice, O. Pizarro, C. Roman, H. Singh Nov 2001

Uwit: Underwater Image Toolbox And Mosaicking In Matlab, R. Eustice, O. Pizarro, C. Roman, H. Singh

Christopher N. Roman

No abstract provided.


A Short Summary Of Seabed And Some Data Highlights, H. Singh, R. Eustice, C. Roman, O. Pizarro, N. Mcphee Nov 2001

A Short Summary Of Seabed And Some Data Highlights, H. Singh, R. Eustice, C. Roman, O. Pizarro, N. Mcphee

Christopher N. Roman

No abstract provided.


Modeling, Fabrication, And Optimization Of Niobium Cavities – Phase I: Quarterly Progress Report August 20, 2001 - November 20, 2001, Robert A. Schill Jr., Mohamed Trabia Nov 2001

Modeling, Fabrication, And Optimization Of Niobium Cavities – Phase I: Quarterly Progress Report August 20, 2001 - November 20, 2001, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Multipacting is one of the major loss mechanisms in rf superconductivity cavities for accelerators. This loss mechanism limits the maximum amount of energy/power supported by the cavities. Optimal designs have been identified in others’ studies. In practice, these designs are not easily manufactured. Chemical etching processes used to polish the cavity walls result in a nonuniform surface etch. A nonuniform surface etch will leave some unclean areas with contaminants and micron size particles. These significantly affect mutipacting. Further, a nonuniform etch will leave areas with damaged grain structure, which is not good for superconducting properties. Typically, the depth of ...


Finite-Element Modeling Of Extraordinary Magnetoresistance In Thin Film Semiconductors With Metallic Inclusions, J. Moussa, L. R. Ram-Mohan, John M. Sullivan Jr., T. Zhou, D. R. Hines, S. A. Solin Nov 2001

Finite-Element Modeling Of Extraordinary Magnetoresistance In Thin Film Semiconductors With Metallic Inclusions, J. Moussa, L. R. Ram-Mohan, John M. Sullivan Jr., T. Zhou, D. R. Hines, S. A. Solin

Mechanical Engineering Faculty Publications

Using finite element analysis, the room temperature extraordinary magnetoresistance recently reported for a modified van der Pauw disk of InSb with a concentric embedded Au inhomogeneity has been calculated, using no adjustable parameters, as a function of the applied magnetic field and the size/geometry of the inhomogeneity. The finite element results are nearly identical to exact analytic results and are in excellent agreement with the corresponding experimental measurements. Moreover, several important properties of the composite InSb/Au system such as the field dependence of the current flow and of the potential on the disk periphery have been deduced, It ...


A Study Of Muscle Activation In A Mathematical Model Of The Human Head And Neck, Janet Brelin-Fornari, A. Arabyan Nov 2001

A Study Of Muscle Activation In A Mathematical Model Of The Human Head And Neck, Janet Brelin-Fornari, A. Arabyan

Mechanical Engineering Presentations And Conference Materials

A model of the human head and neck that incorporates active and passive muscles is utilized in the analysis of non-impact loading in high “g” environments. The active muscles have the capability to be activated partially and in different combinations.The model is implemented in MADYMO using lumped parameters and Hill muscles. A comparison of simulation results with experimental data, generated by the Naval Biodynamics Laboratory (NBDL) for neck flexion and rebound, shows excellent agreement for a 15g impulsive load.


Ortho-Planar Linear-Motion Springs, John J. Parise, Larry L. Howell, Spencer P. Magleby Nov 2001

Ortho-Planar Linear-Motion Springs, John J. Parise, Larry L. Howell, Spencer P. Magleby

Faculty Publications

This paper presents an ortho-planar spring design that operates by raising or lowering its platform relative to the base with no rotation. The compact nature of the design, and its non-rotating motion, eliminates the problem of rotation against adjoining surfaces and is less sensitive to variation in assemblies than many current compact springs. Nomenclature is presented to identify different configurations, mathematical equations are provided that accurately model the force-defection relationships, and a pneumatic valve positioner application is demonstrated.


Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh Oct 2001

Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh

Christopher N. Roman

Creating geometrically accurate photomosaics of underwater sites using images collected from an AUV or ROV is a difficult task due to dimensional errors which grow as a function of 3D image distortion and the mosaicking process. Although photomosiacs are accurate locally their utility for accurately representing a large survey area is jeopardized by this error growth. Evaluating the error in a mosaic is the first step in creating globally accurate photomosaics of an unstructured environment with bounded error. Using vehicle navigation data and sensor offsets it is possible to estimate the error present in large area photomosaics independent of the ...


Crash Attenuation System, John D. Reid, John R. Rohde, Dean L. Sicking Oct 2001

Crash Attenuation System, John D. Reid, John R. Rohde, Dean L. Sicking

Mechanical & Materials Engineering Faculty Publications

A crash attenuation system having an impact head, and energy absorption mechanism. The energy absorbing mechanism has a mandrel for rupturing thin-walled tubes in a controlled rupture to absorb impact forces from a colliding vehicle. A frame may be used to mount the system to a truck, trailer, guardrail, median barrier end treatment, or a crash cushion. Stress concentrators may be incorporated into the tubes and the mandrels to selectively control rupturing and energy dissipation.


Oct 2001, Tractor Museum Oct 2001

Oct 2001, Tractor Museum

Museum Planning and Development Documents

Software Program Storage Space Needed 16 new members


Automatic Compact Disc Transfer For Quality Assurance Testing, Ravi P. Ramachandran, John Chen, Linda M. Head, John L. Schmalzel, Hampton C. Gabler Oct 2001

Automatic Compact Disc Transfer For Quality Assurance Testing, Ravi P. Ramachandran, John Chen, Linda M. Head, John L. Schmalzel, Hampton C. Gabler

Mechanical Engineering

The purpose of this project was to design, build and test a low cost prototype that transfers compact discs (CDs) from a spindle to a computer based testing station. This will speed up the CD production/testing interface and eliminate the need for manual operation. Along with a heavy product design technical component, the project included a real life educational experience for the four students who got credit for a one year advanced senior project. Various designs were considered and the optimal design (based on cost and performance) was prototyped.


Fabrication Of 2- And 3-Dimensional Nanostructures, Hong Jiang, Camelia N. Borca, Bo Xu, Brian W. Robertson Oct 2001

Fabrication Of 2- And 3-Dimensional Nanostructures, Hong Jiang, Camelia N. Borca, Bo Xu, Brian W. Robertson

Mechanical & Materials Engineering Faculty Publications

Amongst tools for fabricating periodic and aperiodic nanostructures and nanodevices, electron beam-induced organometallic chemical vapor deposition (E-OMCVD) offers a highly flexible and controllable one-step deposition process. E-OMCVD enables maskless fabrication of nanoscale research and custom structures that have least dimensions near or below 10 nm–a scale at which other methods prove difficult or costly. Using the focused electron beam in a modified HB501 field-emission scanning transmission electron microscope (STEM), pads and wires with uniform thickness and well-defined shapes have been defined and deposited. Although conditions for fabricating the smallest deposits have not yet been optimized, the edge acuity (sharpness ...


The Uiuc Virtual Spectrometer: A Java-Based Collaborative Learning Environment, Michael C. Dorneich, Patricia M. Jones Oct 2001

The Uiuc Virtual Spectrometer: A Java-Based Collaborative Learning Environment, Michael C. Dorneich, Patricia M. Jones

Michael C. Dorneich

The development of the UIUC Virtual Spectrometer (UIUC-VS), an interactive, Java-based simulation and tutoring system, is discussed. The apprenticeship model oflearning is utilized to create a learning environment for the study of a one-dimensional proton nuclear magnetic resonance (NMR) experiment, with the goal of linking theoretical knowledge with practical operational experience. Active, exploratory, apprentice-style learning is supported via modes of operation within the system. Students can flexibly choose to "observe the expert" perform and explain operational steps, or "act as an apprentice" and carry out the steps autonomously. Students can switch between modes at their discretion, giving them control of ...


Phase References And Cell Effects In Photoacoustic Spectroscopy, Roger W. Jones, John F. Mcclelland Oct 2001

Phase References And Cell Effects In Photoacoustic Spectroscopy, Roger W. Jones, John F. Mcclelland

Ames Laboratory Publications

In Fourier transform infrared (FT-IR) photoacoustic spectroscopy, advanced scanning and data-handling techniques have placed increasing emphasis on the phase of the photoacoustic signal. Unfortunately, there is no agreement on the best material to use as a phase reference. We have examined the frequency dependence of the signal from several candidate phase references and found that cell effects dominate the absolute phases and magnitudes observed. The absolute phase is exceptionally fast at low frequencies and exceptionally slow at high frequencies because of the cell effects. Accordingly, details such as sample position must be scrupulously controlled to achieve accurate, reproducible results. Because ...


Ole Miss Engineer 2001 Oct 2001

Ole Miss Engineer 2001

The Ole Miss Engineer

No abstract provided.


Dynamics Of Sulfur Dioxide Absorption In A Raindrop Falling, Wei-Hsin Chen Sep 2001

Dynamics Of Sulfur Dioxide Absorption In A Raindrop Falling, Wei-Hsin Chen

Wei-Hsin Chen

No abstract provided.


Spatial Mechanism Design In Virtual Reality With Networking, John N. Kihonge, Judy M. Vance, Pierre M. Larochelle Sep 2001

Spatial Mechanism Design In Virtual Reality With Networking, John N. Kihonge, Judy M. Vance, Pierre M. Larochelle

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Mechanisms are used in many devices to move a rigid body through a finite sequence of prescribed locations in space. The most commonly used mechanisms are four-bar planar mechanisms that move an object in one plane in space. Spatial mechanisms allow motion in three-dimensions (3D). Spatial 4C mechanisms are two degree of freedom kinematic closed-chains consisting of four rigid links simply connected in series by cylindrical (C) joints. A cylindrical joint is a two degree of freedom joint which allows translation along and rotation about a line in space. This paper describes a synthesis process for the design of 4C ...


The Use Of The Voxmap Pointshell Method Of Collision Detection In Virtual Assembly Methods Planning, Tom C. Johnson, Judy M. Vance Sep 2001

The Use Of The Voxmap Pointshell Method Of Collision Detection In Virtual Assembly Methods Planning, Tom C. Johnson, Judy M. Vance

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Virtual reality (VR) provides the ability to work with digital models in an environment that provides 3 dimensional interaction. This technology can be used to evaluate how humans interact with products before costly physical prototypes are built. One of the advantages of using VR technology in design evaluation is the ability to easily explore many different "what-if" design scenarios. One of the areas of current research in the use of VR is in assembly methods planning. As a result of prior work performed at Iowa State University, it became clear that collision detection is an important component in the development ...


Effectiveness Of Haptic Sensation For The Evaluation Of Virtual Prototypes, Sergei A. Volkov Sep 2001

Effectiveness Of Haptic Sensation For The Evaluation Of Virtual Prototypes, Sergei A. Volkov

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Virtual Reality techniques provide a unique new way to interact with three-dimensional digital objects. Virtual prototyping refers to the use of virtual reality to obtain evaluations of designs while they are still in digital form before physical prototypes are built. While the current state-of-the-art in virtual reality relies mainly on the use of stereo viewing and auditory feedback, commercial haptic devices have recently become available that can be integrated into the virtual environment to provide force feedback to the user. This paper outlines a study that was performed to determine whether the addition of force feedback to the virtual prototyping ...


Dynamic Friction Of Uhmwpe Angular Compliant Bearing For Joint Implants And Machinery, Max Roman Aug 2001

Dynamic Friction Of Uhmwpe Angular Compliant Bearing For Joint Implants And Machinery, Max Roman

Theses

The feasibility of a unique design of orthopedic- joint implant is investigated. The work focuses on the dynamic friction characteristics of a new joint. This unique design can be also useful in machinery involving oscillating motion similar to that of the hip joint during walking. An elastomeric layer bonded behind the rigid acetubular cup can be beneficial in improving the durability of prosthetic implants. Angular compliance offered by the elastomeric layer reduces relative sliding between the surfaces, lowers contact stresses by distributing pressure more evenly, and reduces the possibility of incongruent loading conditions caused by misalignment. The application of a ...


Mechanical Design Of The Heater Used In Near Infrared Filter, Jun Ma Aug 2001

Mechanical Design Of The Heater Used In Near Infrared Filter, Jun Ma

Theses

This thesis presents a design and analytical process in the application of the heater used in a near infrared filter working in Big Bear Solar Observatory, CA. The objective of the project is to achieve the physics parameters for the filter, which will be used in the observation of the solar activity.

The most important part of this design is to keep a relatively fixed temperature inside the oven-like heater. The reason is that optical properties of calcite (kind of filter in telescope) are pretty sensitive to a tiny disturbance on inside temperature. This was the biggest issue in this ...


Buckling Of Composite Conical Shells Under Combined Axial Compression, External Pressure, And Bending, Youngjin Chung Aug 2001

Buckling Of Composite Conical Shells Under Combined Axial Compression, External Pressure, And Bending, Youngjin Chung

Dissertations

Conical shells are extensively used in space crafts, robots, shelters, domes, tanks, and in machinery or devices (e.g. as Belleville washers). Thus, the design of minimum weight, maximum strength, stiffened conical (and cylindrical) shells under combined loads has long been of interest to designers. The objective of this study is to improve the strength of conical shells and reduce the weight of the structure. Buckling of composite conical shells subjected to combined axial loading, external pressure, and bending is investigated using energy and finite element methods. The conical shells have single and multiple layers, different cone angle, length, and ...


Integration Of E-Business Strategy For Multi-Lifecycle Production Systems, Yanchun Luo Aug 2001

Integration Of E-Business Strategy For Multi-Lifecycle Production Systems, Yanchun Luo

Dissertations

Internet use has grown exponentially on the last few years becoming a global communication and business resource. Internet-based business, or e-Business will truly affect every sector of the economy in ways that today we can only imagine. The manufacturing sector will be at the forefront of this change. This doctoral dissertation provides a scientific framework and a set of novel decision support tools for evaluating, modeling, and optimizing the overall performance of e-Business integrated multi-lifecycle production systems. The characteristics of this framework include environmental lifecycle study, environmental performance metrics, hyper-network model of integrated e-supply chain networks, fuzzy multi-objective optimization method ...