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2006

Mechanical Engineering

Iowa State University

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Carbon Monoxide Mass Transfer In A Syngas Mixture, Amir Kapic, Samuel T. Jones, Theodore J. Heindel Dec 2006

Carbon Monoxide Mass Transfer In A Syngas Mixture, Amir Kapic, Samuel T. Jones, Theodore J. Heindel

Mechanical Engineering Publications

A myoglobin assay for measuring concentrations of dissolved carbon monoxide (CO) from an artificial synthesis gas blend (20% CO, 18% CO2, 52% N2, and 10% H2) was utilized to determine volumetric CO−water mass-transfer rates in a 0.211-m-diameter stirred-tank reactor (STR). The data are well correlated using the power density and superficial gas velocity, but this correlation is valid only for this STR size. A gas−liquid scale-up model developed for dissolved oxygen mass-transfer rates using air was used to develop a CO−liquid scale-up model for syngas fermentation. The model is applicable in the STR hydrodynamic range associated ...


Dynamics And Structures Of Segregation In A Dense, Vibrating Granular Bed, Jin Sun, Francine Battaglia, Shankar Subramaniam Dec 2006

Dynamics And Structures Of Segregation In A Dense, Vibrating Granular Bed, Jin Sun, Francine Battaglia, Shankar Subramaniam

Mechanical Engineering Publications

We study the rise dynamics of a large particle in a granular bed under vertical vibration using molecular dynamics simulations. Systematic variation of the particle properties and external wall friction in the simulations shows that the large particle rising is very sensitive to external wall friction. The dynamical response of the granular bed with wall friction is shown to include an expansion stage and a compression stage within one cycle. With wall friction, large-scale force networks bearing larger-than-average forces are found in the compression stage. However, without wall friction, large strong force networks do not exist. The distribution of normal ...


High-Resolution, Real-Time Three-Dimensional Shape Measurement, Song Zhang, Peisen S. Huang Dec 2006

High-Resolution, Real-Time Three-Dimensional Shape Measurement, Song Zhang, Peisen S. Huang

Song Zhang

We describe a high-resolution, real-time 3-D shape measurement system based on a digital fringe projection and phase-shifting technique. It utilizes a single-chip digital light processing projector to project computer-generated fringe patterns onto the object, and a high-speed CCD camera synchronized with the projector to acquire the fringe images at a frame rate of 120frames∕s. A color CCD camera is also used to capture images for texture mapping. Based on a three-step phase-shifting technique, each frame of the 3-D shape is reconstructed using three consecutive fringe images. Therefore the 3-D data acquisition speed of the system is 40frames∕s. With ...


Modeling Of The Size Effects On The Behavior Of Metals In Microscale Deformation Processes, Gap-Yong Kim, Jun Ni, Muammer Koc Dec 2006

Modeling Of The Size Effects On The Behavior Of Metals In Microscale Deformation Processes, Gap-Yong Kim, Jun Ni, Muammer Koc

Gap-Yong Kim

For the accurate analysis and design of microforming process, proper modeling of material behavior at the micro/mesoscale is necessary by considering the size effects. Two size effects are known to exist in metallic materials. One is the “grain size” effect, and the other is the “feature/specimen size” effect. This study investigated the feature/specimen size effect and introduced a scaling model which combined both feature/specimen and grain size effects. Predicted size effects were compared with three separate experiments obtained from previous research: a simple compression with a round specimen, a simple tension with a round specimen, and ...


Numerical Simulations Of Gas-Liquid Flow Dynamics In Bubble Columns, Deify Law, Francine Battaglia, Theodore J. Heindel Nov 2006

Numerical Simulations Of Gas-Liquid Flow Dynamics In Bubble Columns, Deify Law, Francine Battaglia, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

There is great potential for using computational fluid dynamics (CFD) as a tool in scale-up and design of bubble columns. Full-scale experimentation in bubble columns is expensive and CFD is an alternative approach to study bubble column hydrodynamics. However, CFD can be computationally intensive as a predictive tool for a full three-dimensional geometry. In this paper, a 0.2 m diameter semi-batch bubble column is numerically simulated and the results are compared to experimental measurements performed by Rampure et al. [1]. The objectives are to examine and determine an appropriate set of numerical parameters and to determine if two-dimensional simulations ...


Modeling Of The Semi-Solid Material Behavior And Analysis Of Micro-/Mesoscale Feature Forming, Gap-Yong Kim, Muammer Koc, Rhet Mayor, Jun Ni Oct 2006

Modeling Of The Semi-Solid Material Behavior And Analysis Of Micro-/Mesoscale Feature Forming, Gap-Yong Kim, Muammer Koc, Rhet Mayor, Jun Ni

Gap-Yong Kim

One of the major challenges in simulation of semi-solid forming is characterizing the complex behavior of a material that consists of both solid and liquid phases. In this study, a material model for an A356 alloy in a semi-solid state has been developed for high solid fractions (>0.6) and implemented into a finite element simulation tool to investigate the micro-/mesoscale feature formation during the forming process. Compared to previous stress models, which are limited to expressing the stress dependency on only the strain rate and the temperature (or the solid fraction), the proposed stress model adds the capability ...


An Experimental Investigation On Semi-Solid Forming Of Micro/Meso-Scale Features, Gap-Yong Kim, Jun Ni, Rhett Mayor, Heesool Kim Oct 2006

An Experimental Investigation On Semi-Solid Forming Of Micro/Meso-Scale Features, Gap-Yong Kim, Jun Ni, Rhett Mayor, Heesool Kim

Gap-Yong Kim

The potentials of semi-solid forming technology have generated much interest regarding its application in micromanufacturing. This study investigates the feasibility of using semi-solid forming technology to produce parts with micro/meso features. An experimental setup has been developed to study the effects of die/punch temperature, initial solid fraction, punch speed, and workpiece shape on the semi-solid forming process. A part has been produced for a microreactor application and has been analyzed with an optical measurement system for feature formation. The results indicated complex interaction among the process parameters and the material flow, which affected the final pin formation. The ...


Phase Field Theory Of Surface- And Size-Induced Microstructures, Valery I. Levitas, D.W. Lee, D. L. Preston Oct 2006

Phase Field Theory Of Surface- And Size-Induced Microstructures, Valery I. Levitas, D.W. Lee, D. L. Preston

Valery I. Levitas

New surface- and size-induced microstructures are found as analytic solutions to a phase field theory of first-order phase transformations. A recently developed exact stability criterion, based on most destabilizing fluctuations, is used to analyze the stability and physical interpretation of each microstructure. Conditions for barrierless surface nucleation, i.e. relationship between surface energy, driving force for the transformation and sample size, are found. If they are met, some of these microstructures are destroyed resulting in the barrierless transformation to alternative phases.


Three-Dimensional Path Planning Of Unmanned Aerial Vehicles Using Particle Swarm Optimization, Jung Leng Foo, Jared S. Knutzon, James H. Oliver, Eliot H. Winer Sep 2006

Three-Dimensional Path Planning Of Unmanned Aerial Vehicles Using Particle Swarm Optimization, Jung Leng Foo, Jared S. Knutzon, James H. Oliver, Eliot H. Winer

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Military operations are turning to more complex and advanced automation technology for minimum risk and maximum efficiency. A critical piece to this strategy is unmanned aerial vehicles (UAVs). UAVs require the intelligence to safely maneuver along a path to an intended target, avoiding obstacles such as other aircrafts or enemy threats. Often automated path planning algorithms are employed to specify targets for a UAV to fly to. To date, path-planning algorithms have been limited to two-dimensional problem formulations. This paper presents a unique three-dimensional path planning problem formulation and solution approach using Particle Swarm Optimization (PSO). The problem formulation was ...


Verve: A General Purpose Open Source Reinforcement Learning Toolkit, Tyler Streeter, James H. Oliver, Adrian Sannier Sep 2006

Verve: A General Purpose Open Source Reinforcement Learning Toolkit, Tyler Streeter, James H. Oliver, Adrian Sannier

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Intelligent agents are becoming increasingly important in our society in applications as diverse as house cleaning robots, computer-controlled opponents in video games, unmanned aerial combat vehicles, entertainment robots, and autonomous explorers in outer space. However, the broader adoption of intelligent agents is often hindered by their limited adaptability to new tasks; when conditions change slightly, agents may quickly become confused. Additionally, a substantial engineering effort is required to design an agent for each new task. This paper presents an adaptable, general purpose intelligent agent toolkit based on reinforcement learning (RL), an approach with strong mathematical foundations and intriguing biological implications ...


Sharp: A System For Haptic Assembly And Realistic Prototyping, Abhishek Seth, Hai-Jun Su, Judy M. Vance Sep 2006

Sharp: A System For Haptic Assembly And Realistic Prototyping, Abhishek Seth, Hai-Jun Su, Judy M. Vance

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Virtual Reality (VR) technology holds promise as a virtual prototyping tool for mechanical assembly; however, several developmental challenges still need to be addressed before virtual prototyping applications can successfully be integrated into the product realization process. This paper describes the development of SHARP (System for Haptic Assembly & Realistic Prototyping), a portable VR interface for virtual assembly. SHARP uses physically-based modeling for simulating realistic part-to-part and hand-to-part interactions in virtual environments. A dual handed haptic interface for realistic part interaction using the PHANToM® haptic devices is presented. The capability of creating subassemblies enhances the application’s ability to handle a wide ...


Object-Centered Engineering: A Methodology For Virtual Engineering, Douglas S. Mccorkle, Kenneth M. Bryden, Daniel A. Ashlock Sep 2006

Object-Centered Engineering: A Methodology For Virtual Engineering, Douglas S. Mccorkle, Kenneth M. Bryden, Daniel A. Ashlock

Mechanical Engineering Conference Presentations, Papers, and Proceedings

In the product realization process, it is not currently possible to go from business case models to the final production system in the virtual design space. Virtual engineering aims to address this problem. Virtual engineering techniques will allow users to track the production of a product or system from birth to death, from the complete business case model to the customer’s feedback on the first production run. To implement a framework that will handle the broad range of information that is necessary to track a product through its complete life cycle, an object-centered approach involving virtual objects is required ...


Novel Method For Structured Light System Calibration, Song Zhang, Peisen S. Huang Aug 2006

Novel Method For Structured Light System Calibration, Song Zhang, Peisen S. Huang

Song Zhang

System calibration, which usually involves complicated and time-consuming procedures, is crucial for any 3-D shape measurement system. In this work, a novel systematic method is proposed for accurate and quick calibration of a 3-D shape measurement system we developed based on a structured light technique. The key concept is to enable the projector to “capture” images like a camera, thus making the calibration of a projector the same as that of a camera. With this new concept, the calibration of structured light systems becomes essentially the same as the calibration of traditional stereovision systems, which is well established. The calibration ...


High-Resolution Real-Time 3d Absolute Coordinates Measurement Using A Fast Three-Step Phase-Shifting Algorithm, Song Zhang, Dale Royer, Shing-Tung Yau Aug 2006

High-Resolution Real-Time 3d Absolute Coordinates Measurement Using A Fast Three-Step Phase-Shifting Algorithm, Song Zhang, Dale Royer, Shing-Tung Yau

Song Zhang

High-resolution, real-time 3-D absolute coordinate measurement is highly important in many fields. This paper presents such a system that measures 3-D absolute geometric shapes and positions at 30 frames per second (fps), with an image resolution of 532 × 500. The system is based on a digital fringe projection and fast three-step phase-shifting method. It utilizes a digital-light-processing (DLP) projector to project color encoded computer generated phase-shifted fringe patterns in grayscale, a high-speed CCD camera synchronized with the projector to capture fringe images at 90 fps. Based on the three-step phase-shifting algorithm, any successive three fringe images can be used to ...


Generic Nonsinusoidal Phase Error Correction For 3d Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau Aug 2006

Generic Nonsinusoidal Phase Error Correction For 3d Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau

Song Zhang

Structured light system using a digital video projector is increasingly used for a 3-D shape measurement because of its digital nature. However, the nonlinear gamma of the projector causes the projected fringe patterns to be non-sinusoidal, which results in phase error therefore shape measurement error. Previous work showed that, by using a small look-up-table (LUT), this type of phase error can be reduced significantly for a three-step phase-shifting algorithm. In this research, we prove that this type of phase error compensation method is not limited to a three-step phase-shifting algorithm. It is generic for any phase-shifting algorithm. The phase error ...


Ginzburg-Landau Theory Of Microstructures: Stability, Transient Dynamics, And Functionally Graded Nanophases, Valery I. Levitas, D. L. Preston, Dong Wook Lee Jul 2006

Ginzburg-Landau Theory Of Microstructures: Stability, Transient Dynamics, And Functionally Graded Nanophases, Valery I. Levitas, D. L. Preston, Dong Wook Lee

Valery I. Levitas

The stability, transient dynamics, and physical interpretation of microstructures obtained from a Ginzburg-Landau theory of first-order phase transformations are studied. The Jacobi condition for stability fails numerically, thus an alternative exact stability criterion, based on critical (most destabilizing) fluctuations, is developed. The degree-of-stability parameter is introduced to quantify the physical stability of long-lived unstable microstructures. For nanofilms, the existence of functionally graded nanophases is demonstrated. Numerical simulations indicate that graded nanophases can be produced by dissolving material from both surfaces of a nanofilm. Stability under finite fluctuations and post-bifurcation microstructure evolution are investigated numerically.


Differentiating Writing Inks Using Direct Analysis In Real Time Mass Spectrometry, Roger W. Jones, Robert B. Cody, John Frederick Mcclelland Jul 2006

Differentiating Writing Inks Using Direct Analysis In Real Time Mass Spectrometry, Roger W. Jones, Robert B. Cody, John Frederick Mcclelland

Ames Laboratory Publications

Writing ink analysis is used in establishing document authenticity and the sources and relative ages of written entries. Most analytical methods require removing samples or visibly altering the document. Nondestructive, in situ analysis of writing inks on paper without visible alteration is possible using mass spectrometry with a new ion source called Direct Analysis in Real Time. Forty-three different black and blue ballpoint, black fluid, and black gel inks were examined. Both dyes and persistent but thermally labile components of the inks contribute to the mass spectra, principally as protonated molecules [M1H]1. Numerous ink components were identified from the ...


Uav Swarm Control: Calculating Digital Pheromone Fields With The Gpu, Bryan Walter, Adrian Sannier, Dirk Reiners, James H. Oliver Jul 2006

Uav Swarm Control: Calculating Digital Pheromone Fields With The Gpu, Bryan Walter, Adrian Sannier, Dirk Reiners, James H. Oliver

Mechanical Engineering Publications

Our future military force will be complex: a highly integrated mix of manned and unmanned units. These unmanned units could function individually or within a swarm. The readiness of future warfighters to work alongside and utilize these new forces depends on the creation of usable interfaces and training simulators. The difficulty is that current unmanned aerial vehicle (UAV) control interfaces require too much operator attention, and common swarm control methods require expensive computational power. This paper begins with a discussion on how to improve upon current user interfaces and then reviews a swarm control method, the digital pheromone field. This ...


Similitude Analysis For Gas-Liquid-Fiber Flows In Cocurrent Bubble Columns, Chengzhi Tang, Theodore J. Heindel Jul 2006

Similitude Analysis For Gas-Liquid-Fiber Flows In Cocurrent Bubble Columns, Chengzhi Tang, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Gas-liquid-fiber systems are different from conventional gas-liquid-solid systems in that the solid material (i.e., fiber) is flexible, has a large aspect ratio, and forms flocs or networks when its mass fraction is above a critical value. With its wide application to the pulp and paper industry, it is important to investigate the hydrodynamics of gas-liquid-fiber systems. In this paper, 19 parameters that influence gas holdup in gas-liquid-fiber bubble columns are critically examined and then a dimensional analysis based on the Buckingham Pi Theorem is used to derive the dimensionless parameters governing gas-liquid-fiber bubble column hydrodynamics. Seven dimensionless parameters that ...


The Effect Of A Modified Downcomer On The Hydrodynamics In An External Loop Airlift Reactor, Samuel T. Jones, Theodore J. Heindel Jul 2006

The Effect Of A Modified Downcomer On The Hydrodynamics In An External Loop Airlift Reactor, Samuel T. Jones, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Gas holdup and superficial liquid velocity in the downcomer and riser are studied for an external loop airlift reactor with an area ratio of 1:16. Two downcomer configurations are investigated consisting of the downcomer open or closed to the atmosphere. Experiments for these two configurations are carried out over a range of superficial gas velocities from UG = 0.5 to 20 cm/s using three aeration plates with open area ratios of 0.62, 0.99 and 2.22%. These results are compared to a bubble column operated with similar operating conditions. Experimental results show that the gas holdup ...


Abstracts, Review Of Progress In Quantitative Nondestructive Evaluation (Portland, Or, July 20–August 4, 2006), Center For Nondestructive Evaluation, Iowa State University Jun 2006

Abstracts, Review Of Progress In Quantitative Nondestructive Evaluation (Portland, Or, July 20–August 4, 2006), Center For Nondestructive Evaluation, Iowa State University

Review of Progress in Quantitative Nondestructive Evaluation

Abstracts of papers presented at the 2006 Review of Progress in Quantitative Nondestructive Evaluation (QNDE) conference held in Portland, Oregon from July 30–August 4, 2006.


Intellectual Property Protection In Collaborative Design Through Lean Information Modeling And Sharing, Yan Wang, Pamela N. Ajoku, José C. Brustoloni, Bart O. Nnaji Jun 2006

Intellectual Property Protection In Collaborative Design Through Lean Information Modeling And Sharing, Yan Wang, Pamela N. Ajoku, José C. Brustoloni, Bart O. Nnaji

Center for e-Design Publications

Establishing efficient, effective, and trustworthy engineering collaboration while protecting intellectual property is vital to maintain organizational competence in today’s global business environment. In this paper, a lean information modeling and sharing framework is described to support engineering data security management in a peer-to-peer collaborative environment. It allows for selective and interoperable data sharing with fine-grained access control at both the server and client sides, thus securing different levels of design information dissemination for intellectual property protection purposes. The considerations of time and value-adding activity with roles, policy delegation relation in a distributed context, and fine-grained control at data set ...


Document-Driven Design For Distributed Cad Services In Service-Oriented Architecture, Yan Wang, Bart O. Nnaji Jun 2006

Document-Driven Design For Distributed Cad Services In Service-Oriented Architecture, Yan Wang, Bart O. Nnaji

Center for e-Design Publications

Current computer-aided design (CAD) systems only support interactive geometry generation, which is not ideal for distributed engineering services in enterprise-to-enterprise collaboration with a generic thin-client service-oriented architecture. This paper proposes a new feature-based modeling mechanism—document-driven design—to enable batch mode geometry construction for distributed CAD systems. A semantic feature model is developed to represent informative and communicative design intent. Feature semantics is explicitly captured as a trinary relation, which provides good extensibility and prevents semantics loss. Data interoperability between domains is enhanced by schema mapping and multiresolution semantics. This mechanism aims to enable asynchronous communication in distributed CAD environments ...


Demonstrating Electromagnetic Noise In An Undergraduate Measurement And Instrumentation Course, David Muff, Theodore J. Heindel, Sriram Sundararajan Jun 2006

Demonstrating Electromagnetic Noise In An Undergraduate Measurement And Instrumentation Course, David Muff, Theodore J. Heindel, Sriram Sundararajan

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Electromagnetic noise (interference) is always present in a measurement system. The desire to minimize noise in your signal of interest can only be accomplished after the noise is properly identified. This paper summarizes a mechanical engineering undergraduate laboratory activity developed for ME 370 – Engineering Measurements and Instrumentation at Iowa State University. The goals of this activity are to (i) develop an understanding of how analog noise enters a measurement system and (ii) investigate several noise reduction methods. Students induce and measure capacitively coupled noise and investigate how the noise is related to noise source frequency and measurement circuit resistance. Methods ...


Updating Mechanical Engineering Measurements And Instrumentation—A Case Study, Theodore J. Heindel Jun 2006

Updating Mechanical Engineering Measurements And Instrumentation—A Case Study, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Measurement and instrumentation is a common course topic in many undergraduate mechanical engineering curricula. This paper summarizes changes to ME 370 – Engineering Measurements and Instrumentation at Iowa State University (ISU), which went through major course revisions from fall 2003 to spring 2005. Modifications to the course include the following: (i) incorporating virtual measurements and instrumentation into the lecture and laboratory, (ii) coupling the lecture and laboratory more closely through an on-line course manual, (iii) providing additional course resources through WebCT to enhance student learning, and (iv) updating and/or developing several new laboratory exercises to demonstrate key course learning objectives ...


Fast Meshless Reanalysis Using Combined Approximations, Preconditioned Conjugate Gradient, And Taylor Series, Kurt A. Chipperfield, Judy M. Vance, Andrew G. Fischer Jun 2006

Fast Meshless Reanalysis Using Combined Approximations, Preconditioned Conjugate Gradient, And Taylor Series, Kurt A. Chipperfield, Judy M. Vance, Andrew G. Fischer

Mechanical Engineering Publications

Multiple design iterations often require repeated stress analyses to be performed as the design is modified slightly. A method is presented that combines the meshless stress analysis method with a reanalysis technique to avoid repeating the time-consuming steps of remeshing and solving for small design changes. An iterative reanalysis method based on the preconditioned conjugate gradient method is introduced and compared to the linear Taylor series, simple iteration, and combined approximations reanalysis methods. The asymptotic running time is presented for each reanalysis method, and accuracy is compared for two example problems: a cantilever beam and a hole-in-plate. Results show the ...


A Web-Based Interface For Complex Design Using A Virtual Engineering Software Framework, Kenneth J. Kopecky, David J. Muth Jr., Douglas S. Mccorkle, Eliot H. Winer, Kenneth M. Bryden May 2006

A Web-Based Interface For Complex Design Using A Virtual Engineering Software Framework, Kenneth J. Kopecky, David J. Muth Jr., Douglas S. Mccorkle, Eliot H. Winer, Kenneth M. Bryden

Mechanical Engineering Conference Presentations, Papers, and Proceedings

VE-Suite is a powerful software framework that allows many complex engineering tasks to be designed, analyzed, and optimized within a comprehensive virtual environment. VESuite is designed to enable the collaboration of engineers across distance and platforms, ranging from immersive Virtual Reality systems to common desktop computers. The purpose of this paper is to describe the development of a web-based interface for VE-Suite. Specific areas covered include the program’s facilities for data storage and retrieval, collaboration methods, and integration with the entire VE-Suite framework. The interface development is presented along with a test case shown within the software framework.


Tailorable, 3d Microfabrication For Photonic Applications: Two-Polymer Microtransfer Molding, Jae-Hwang Lee, Chang-Hwan Kim, Kristen P. Constant, Kai-Ming Ho Mar 2006

Tailorable, 3d Microfabrication For Photonic Applications: Two-Polymer Microtransfer Molding, Jae-Hwang Lee, Chang-Hwan Kim, Kristen P. Constant, Kai-Ming Ho

Materials Science and Engineering Conference Papers, Posters and Presentations

For photonic devices, extending beyond the planar regime to the third dimension can allow a higher degree of integration and novel functionalities for applications such as photonic crystals and integrated optical circuits. Although conventional photolithography can achieve both high quality and structural control, it is still costly and slow for threedimensional (3D) fabrication. Moreover, as diverse functional polymers emerge, there is potential to develop new techniques for quick and economical fabrication of 3D structures. We present a 3D microfabrication technique based on the soft lithographic technique, called two-polymer microtransfer molding (2P-µTM) to accomplish low cost, high structural fidelity and tailorable ...


Development Of A Virtual Environment For Interactive Interrogation Of Computational Mixing Data, Thomas J. Duncan, Judy M. Vance Feb 2006

Development Of A Virtual Environment For Interactive Interrogation Of Computational Mixing Data, Thomas J. Duncan, Judy M. Vance

Mechanical Engineering Publications

Virtual reality (VR) has the potential to enable visualization of complex physical phenomena in their natural spatial scales and significantly improve the product development process. Virtual environments provide a tool for users to interact with three-dimensional models using intuitive methods in their natural spatial scales. This paper presents the implementation details of a virtual environment combining surround-screen virtual reality technology and particle tracing of massless particles to explore the benefits these tools bring to engineers seeking to understand the complex fluid behavior present in mixing processes. The implementation of interaction methods, including volume data selection using a convex hull approach ...


Corrugation And Buckling Defects In Wound Rolls, Jonathan A. Wickert, P.M. Lin Feb 2006

Corrugation And Buckling Defects In Wound Rolls, Jonathan A. Wickert, P.M. Lin

Jonathan A. Wickert

Sheet metal, paper, and polymer webs are often stored and processed as large rolls comprising thousands of layers. Depending on the elastic properties of the web material, the roll's dimensions, the type of core, and the winding tension, the stresses that develop within the roll can be sufficiently high to cause local or gross buckling defects to form. For instance, the cylindrical core onto which the web is wound can collapse, a failure mode that is termed "v-buckling." In other cases, while the core might remain intact, a group of layers interior to the roll can wrinkle into a ...