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2009

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Articles 31 - 60 of 120

Full-Text Articles in Engineering Science and Materials

On Controlled Linear Diffusions With Delay In A Model Of Optimal Advertising Under Uncertainty With Memory Effects, Fausto Gozzi, Carlo Marinelli, Sergei Savin Aug 2009

On Controlled Linear Diffusions With Delay In A Model Of Optimal Advertising Under Uncertainty With Memory Effects, Fausto Gozzi, Carlo Marinelli, Sergei Savin

Operations, Information and Decisions Papers

We consider a class of dynamic advertising problems under uncertainty in the presence of carryover and distributed forgetting effects, generalizing the classical model of Nerlove and Arrow (Economica 29:129–142, 1962). In particular, we allow the dynamics of the product goodwill to depend on its past values, as well as previous advertising levels. Building on previous work (Gozzi and Marinelli in Lect. Notes Pure Appl. Math., vol. 245, pp. 133–148, 2006), the optimal advertising model is formulated as an infinite-dimensional stochastic control problem. We obtain (partial) regularity as well as approximation results for the corresponding value function. Under ...


The Effects Of Combined Compression And Aging On The Properties Of Glassy Polycarbonate, Kyle W. Strabala Aug 2009

The Effects Of Combined Compression And Aging On The Properties Of Glassy Polycarbonate, Kyle W. Strabala

Engineering Mechanics Dissertations & Theses

Physical aging and plastic flow are known to cause changes in the properties of glassy polycarbonate (PC). Although the individual effects of physical aging and plastic flow have been studied, the combined mechanical and thermal effects have yet to be evaluated for PC at large plastic strains. This work is the first characterization of the combined effects in PC of large plastic flow followed by thermal (physical) aging. To conduct this study, samples were prepared with different extents of plastic compressive strain, up to approximately 50% engineering strain, followed by thermal aging up to 135 °C, with various aging times ...


Flame Retardant Mattress Pads, Manjeshwar Ganeshaq Kamath Aug 2009

Flame Retardant Mattress Pads, Manjeshwar Ganeshaq Kamath

Doctoral Dissertations

Focus of this research is on developing cotton-based nonwoven mattress pads with flame retardant (FR) properties by blending cotton with other commercially available fibers, binders, and followed by chemical treatments; offering a cost-effective recipe to meet the upcoming flammability standards. Furthermore this research explores the opportunities taking advantage of possible synergistic effects to achieve maximum performance.

Recent changes in the flammability regulations require improvements in the flame resistance of cotton-containing consumer goods such as upholstered furniture, mattresses, and pillows. Cotton, synthetic fibers, fabrics, and foam are the basic constituents of these goods that are often the first to be engulfed ...


Development And Integration Of Geometric And Optimization Algorithms For Packing And Layout Design, Santosh Tiwari Aug 2009

Development And Integration Of Geometric And Optimization Algorithms For Packing And Layout Design, Santosh Tiwari

All Dissertations

The research work presented in this dissertation focuses on the development and application of optimization and geometric algorithms to packing and layout optimization problems. As part of this research work, a compact packing algorithm, a physically-based shape morphing algorithm, and a general purpose constrained multi-objective optimization algorithm are proposed. The compact packing algorithm is designed to pack three-dimensional free-form objects with full rotational freedom inside an arbitrary enclosure such that the packing efficiency is maximized. The proposed compact packing algorithm can handle objects with holes or cavities and its performance does not degrade significantly with the increase in the complexity ...


Survey Of Concurrent Engineering Environments And The Application Of Best Practices Towards The Development Of A Multiple Industry, Multiple Domain Environment, Jonathan Osborn Aug 2009

Survey Of Concurrent Engineering Environments And The Application Of Best Practices Towards The Development Of A Multiple Industry, Multiple Domain Environment, Jonathan Osborn

All Theses

This thesis investigates the best practices of fifteen existing Concurrent Engineering Environments (CEE). A CEE is defined as any environment, from physical to virtual, designed to facilitate concurrent engineering with multiple domain experts real time. All existing environments surveyed have been focused on the aerospace industry showing significant reductions in design time and cost. I have identified hardware, software, and peopleware as three major classifications as well as sixteen subcategories with which to compare the different CEEs. The success in reducing time and cost of designs seen in the aerospace industry with the introduction of CEEs can and should be ...


Dynamic Finite Element Simulation Of Ultrasonic Consolidation, Daniel Mccullough Aug 2009

Dynamic Finite Element Simulation Of Ultrasonic Consolidation, Daniel Mccullough

All Theses

Ultrasonic Consolidation (UC) is a promising solid state rapid manufacturing process that provides the ability to create functional, multilayered, and often geometrically complex parts. This thesis seeks to address one of the primary obstacles faced when using the process, namely the apparent build height limit encountered when using UC to construct high aspect ratio specimens. A fully transient, three dimensional Finite Element model is created to study the dynamic behavior of an ultrasonically consolidated part during the UC process. The model is used to find the cause of bond failure at the build height limit and a potential way to ...


Characterization And Enhancement Of Sensing Properties Of Piezoelectric Materials With Applications To Vibration Suppression, Siddharth Aphale Aug 2009

Characterization And Enhancement Of Sensing Properties Of Piezoelectric Materials With Applications To Vibration Suppression, Siddharth Aphale

All Theses

This thesis undertakes the study of piezoelectric properties of polymer-based fabric and film sensors. An enhancement in piezoelectric properties of such sensors, as noted through earlier work, is observed with increasing weight ratios of nanomaterials dispersed in the polymer matrix. A comprehensive mathematical model using cantilever beams is developed to analyze this enhancement both qualitatively and quantitatively. An experimental setup is also developed to implement the proposed real time signal processing necessary to collect required data towards the characterization. In order to distinguish piezoelectric materials from other materials, study of the frequency response of developed fabric sensors to periodic chirp ...


Development Of A Rigid Ring Tire Model And Comparison Among Various Tire Models For Ride Comfort Simulations, Norm Frey Aug 2009

Development Of A Rigid Ring Tire Model And Comparison Among Various Tire Models For Ride Comfort Simulations, Norm Frey

All Theses

One vehicle subassembly that is of great importance to automobile manufacturers for tuning final vehicle performance is the pneumatic tire. Pneumatic tires present themselves as unique tuning tools as they 1) are the sole link between the roadway surface and the integrated vehicle suspension, chassis and steering systems, and 2) provide a wide range of tunability over many vehicle performances, including handling (steering feel as well as chassis dynamics), traction (braking, driving, and cornering), and ride comfort (roadway isolation). Therefore the vehicle manufacturing industry continues to research and refine various aspects of tire modeling to improve up-front integrated tire/vehicle ...


Use Of Orthogonal Arrays For Efficient Evaluation Of Geometric Designs For Reducing Vibration Of A Non-Pneumatic Wheel During High-Speed Rolling, William Rutherford Aug 2009

Use Of Orthogonal Arrays For Efficient Evaluation Of Geometric Designs For Reducing Vibration Of A Non-Pneumatic Wheel During High-Speed Rolling, William Rutherford

All Theses

During high speed rolling of a non-pneumatic wheel, vibration may be produced by the interaction of collapsible spokes with a shear deformable ring as they enter the contact region, buckle and then snap back into a state of tension. In the present work, a 2D planar finite element model with geometric nonlinearity and explicit time-stepping is used to simulate rolling of the non-pneumatic wheel. Vibration characteristics are measured from the FFT frequency spectrum of the time-signals of perpendicular distance of marker nodes from the virtual plane of the spoke, thickness change in the ring between spokes, and ground reaction forces ...


Predictive Energy Management In Smart Vehicles: Exploiting Traffic And Traffic Signal Preview For Fuel Saving, Behrang Asadi Aug 2009

Predictive Energy Management In Smart Vehicles: Exploiting Traffic And Traffic Signal Preview For Fuel Saving, Behrang Asadi

All Theses

This master thesis proposes methods for improving fuel economy and emissions of vehicles via use of future information of state of traffic lights, traffic flow, and deterministic traffic flow models.
The first part of this thesis proposes use of upcoming traffic signal information
within the vehicle's adaptive cruise control system to reduce idle time at stop lights and lower fuel use. To achieve this goal an optimization-based control algorithm is formulated for each equipped vehicle that uses short range radar and traffic signal information predictively to schedule an optimum velocity trajectory for the vehicle. The objectives are timely arrival ...


On The Modeling Of Energy Harvesters And Analysis Of Their Response Under Time-Varying Frequency Excitations, Thiago Seuaciuc-Osorio Aug 2009

On The Modeling Of Energy Harvesters And Analysis Of Their Response Under Time-Varying Frequency Excitations, Thiago Seuaciuc-Osorio

All Theses

Energy harvesting is a process by which otherwise wasted ambient energy can be captured and transformed into a useful form. Historical examples of this concept include windmills, sailing ships, and waterwheels. Modern technologies and current energy needs have brought this same concept to a smaller scale wherein small wireless devices with minute energy consumption can be operated autonomously. Today, many critical electronic devices, such as health-monitoring sensors, pace makers, spinal stimulators, electric pain relievers, etc. require minimal amounts of power to function, which permits utilizing energy from their environment to power them. By exploiting the ability of active materials and ...


High Resolution X-Ray Tomography Of Fiber Reinforced Polymeric Composites, Stephen Andrew Young Aug 2009

High Resolution X-Ray Tomography Of Fiber Reinforced Polymeric Composites, Stephen Andrew Young

Masters Theses

A high resolution x-ray tomography system was used to study chopped fiber polymeric composites made of polypropylene resin, nickel coated carbon fiber and Eglass fiber. Procedures are developed to obtain micro-structured features of importance. In-situ tensile testing system was developed and integrated into the existing hardware for tomography equipment to study the evolution of damage and micro-structural features as a function of mechanical stress. High resolution x-ray tomographic images of glass fiber were collected and viewed on a micron scale. The radiographs were reconstructed to visualize the fiber content of the samples in three dimensional volume. In addition, glass fiber ...


Abstracts, Review Of Progress In Quantitative Nondestructive Evaluation (Kingston, Ri, July 26–31, 2009), Center For Nondestructive Evaluation, Iowa State University Jul 2009

Abstracts, Review Of Progress In Quantitative Nondestructive Evaluation (Kingston, Ri, July 26–31, 2009), Center For Nondestructive Evaluation, Iowa State University

Review of Progress in Quantitative Nondestructive Evaluation

Abstracts of papers presented at the 2009 Review of Progress in Quantitative Nondestructive Evaluation (QNDE) conference held in Kingston, Rhode Island from July 26–31, 2009.


A Review On Load Flow Studies, Dr. Adel A. Elbaset Jul 2009

A Review On Load Flow Studies, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

No abstract provided.


Controlled Islanding Scheme For Power Systems, Dr. Adel A. Elbaset Jul 2009

Controlled Islanding Scheme For Power Systems, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

No abstract provided.


Multiscale Modeling Of Glass Fiber Reinforced Viscoelastic Polymers Subjected To Impact Loads, Victor Ferreira Teixeira Jun 2009

Multiscale Modeling Of Glass Fiber Reinforced Viscoelastic Polymers Subjected To Impact Loads, Victor Ferreira Teixeira

Engineering Mechanics Dissertations & Theses

New applications for polymer composite materials are occurring at a rapid pace today. These include structural components in the energy, transportation, and biomedical fields. Many if not all of these new applications will require that part performance is insured with some degree of sustainable damage. With the growth in the use of composite structures comes the necessity of improved methodologies that can predict more accurately the life and serviceability conditions of composite parts. Damage mechanics in two-phase composite materials is a very complex problem that has challenged researchers for many years. However, most of the available models perform only a ...


Seminar In Kumamoto University, 11-6-2009 (Protection), Dr. Adel A. Elbaset Jun 2009

Seminar In Kumamoto University, 11-6-2009 (Protection), Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

This Seminar about a Novel protective scheme for Transmission line Presented by me in Kumamoto University, Graduate School of Science and Technology, Japan at 11-6-2009.


Comparison Between Direct Quadrature Method Of Moments And The Method Of Classes For Bubbly Flow, Brahim Selma, Rachid Bannari, Pierre Proulx Jun 2009

Comparison Between Direct Quadrature Method Of Moments And The Method Of Classes For Bubbly Flow, Brahim Selma, Rachid Bannari, Pierre Proulx

Rachid BANNARI

No abstract provided.


Design And Cfd Analysis Of Mass Transfer And Shear Stresses Distributions In Airlift Reactor, Rachid Bannari, Brahim Selma, Abdelfettah Bannari, Pierre Proulx Jun 2009

Design And Cfd Analysis Of Mass Transfer And Shear Stresses Distributions In Airlift Reactor, Rachid Bannari, Brahim Selma, Abdelfettah Bannari, Pierre Proulx

Rachid BANNARI

The design, scale-up and performance evaluation of biological reactors require accurate information about the gas-liquid flow dynamics. In this study, we use CFD techniques to investigate important parameters of the multiphase flow dynamics on an initial airlift bioreactor in order to improve its design. Such parameters are distributions of shear stresses and mass transfer. Our initial proposed design of the airlift bioreactor was used for biomass growing. Specifically to produce cellulase enzyme using the fungus Trichoderma Reesei. However, the morphology of the microorganism obtained in this bioreactor was not appropriated to produce cellulase. Since the microorganism morphology presented a small ...


Flexible Electronics Using Ion Implantation To Adhere Polymer Substrate To Single Crystal Silicon Substrate, Terry L. Alford, Douglas C. Thompson Jr., Hyunchul Kim, Michael A. Nastasi, James W. Mayer, Daniel Adams Jun 2009

Flexible Electronics Using Ion Implantation To Adhere Polymer Substrate To Single Crystal Silicon Substrate, Terry L. Alford, Douglas C. Thompson Jr., Hyunchul Kim, Michael A. Nastasi, James W. Mayer, Daniel Adams

Mechanical & Materials Engineering Faculty Publications

An electronic apparatus uses a single crystalline silicon Substrate disposed adjacent to a flexible substrate. The electronic apparatus may be a flexible flat panel display, or a flexible printed circuit board. The flexible substrate can be made from polymer, plastic, paper, flexible glass, and stainless steel. The flexible substrate is bonded to the single crystalline substrate using an ion implantation process. The ion implantation process involves the use of a noble gas Such as hydrogen, helium, Xenon, and krypton. A plurality of semiconductor devices are formed on the single crystalline silicon Substrate. The semi conductor devices may be thin film ...


Recent Advances In Model-Assisted Probability Of Detection, R. Bruce Thompson, Lisa H. Brasche, D. Forsyth, E. Lindgren, P. Swindell, W. Winfree Jun 2009

Recent Advances In Model-Assisted Probability Of Detection, R. Bruce Thompson, Lisa H. Brasche, D. Forsyth, E. Lindgren, P. Swindell, W. Winfree

Center for Nondestructive Evaluation Conference Papers, Posters and Presentations

The increased role played by probability of detection (POD) in structural integrity programs, combined with the significant time and cost associated with the purely empirical determination of POD, provides motivation for alternate means to estimate this important metric of NDE techniques. One approach to make the process of POD estimation more efficient is to complement limited empirical experiments with information from physics-based models of the inspection process or controlled laboratory experiments. The Model-Assisted Probability of Detection (MAPOD) Working Group was formed by the Air Force Research Laboratory, the FAA Technical Center, and NASA to explore these possibilities. Since the 2004 ...


Microcantilever-Based Force Sensing, Control And Imaging, Reza Saeidpourazar May 2009

Microcantilever-Based Force Sensing, Control And Imaging, Reza Saeidpourazar

All Dissertations

This dissertation presents a distributed-parameters base modeling framework for microcantilever (MC)-based force sensing and control with applications to nanomanipulation and imaging. Due to the widespread applications of MCs in nanoscale force sensing or atomic force microscopy with nano-Newton to pico-Newton force measurement requirements, precise modeling of the involved MCs is essential. Along this line, a distributed-parameters modeling framework is proposed which is followed by a modified robust controller with perturbation estimation to target the problem of delay in nanoscale imaging and manipulation. It is shown that the proposed nonlinear model-based controller can stabilize such nanomanipulation process in a very ...


Development, Parameterization And Validation Of Dynamic Material Models For Soil And Transparent Armor Glass, Bhaskar Pandurangan May 2009

Development, Parameterization And Validation Of Dynamic Material Models For Soil And Transparent Armor Glass, Bhaskar Pandurangan

All Dissertations

Despite the signing of several mine ban treaties in the 1990's, it is widely recognized that there is a landmine crisis. The following are some of the main aspects of this crisis: (a) Millions of unexploded landmines remain deployed all over the world; (b) Thousands of civilians are killed or maimed every year by unintended detonations of the mines; (c) The cost of medical treatment of landmine injuries runs into the millions; (d) the ability of the international community to provide the humanitarian relief in terms of medical services, safe drinking water and food, etc., is greatly hampered by ...


Foundations Of Design Method Development, Sudhakar Teegavarapu May 2009

Foundations Of Design Method Development, Sudhakar Teegavarapu

All Dissertations

A systematic procedure for developing design methods, tools, and/or processes, referred to as meta-method, is proposed. It is hypothesized that design methods developed without following a systematic procedure are not effective and thus are not widely accepted by industry and academia likewise. The systematic framework provided by the meta-method will ensure 1) faster development of design methods, 2) enable tracking of requirements throughout the development process, 3) facilitate efficient exploration and selection of alternatives, 4) document the development process for future reuse, 5) help in testing and validation of design methods, and 6) bridge gap between multiple disciplines by ...


Development Of A Nonlinear Ride Quality Model To Aid In Tweelå© Parameter Selection, Marc Paradiso May 2009

Development Of A Nonlinear Ride Quality Model To Aid In Tweelå© Parameter Selection, Marc Paradiso

All Theses

The ride comfort of a vehicle is very important to both automotive and tire manufacturers. Unfortunately the ride comfort provided by the tire has an inverse relationship with the handling ability of the vehicle. Michelin has sought to decouple ride comfort and handling capability by developing a non-pneumatic tire they have dubbed the TWEEL©. To better understand what effects fitting a TWEEL with specific characteristics would have on the ride comfort of a vehicle a computer simulation was developed to study the effects of TWEEL stiffness and deflection on ride comfort.
The vehicle model used in the simulation is a ...


An Evaluation Of Function-Based Representations And Information Archival In Engineering Design, Benjamin Caldwell May 2009

An Evaluation Of Function-Based Representations And Information Archival In Engineering Design, Benjamin Caldwell

All Theses

Recent research in function-based design includes the development of a vocabulary of functions, the Functional Basis, and a repository of products and their functions. Many design tools are being developed around this vocabulary and repository to support conceptual design. The usefulness of these tools, however, is dependent on the quality of the vocabulary and the information contained in the repository. In this research, both the vocabulary and the repository are empirically evaluated to understand their strengths and limitations. A statistical analysis is performed on function models in the repository to determine the frequency of usage of Functional Basis terms. It ...


A Study In The Information Content, Consistency, And Expressive Power Of Function Structures In Mechanical Design, Chiradeep Sen May 2009

A Study In The Information Content, Consistency, And Expressive Power Of Function Structures In Mechanical Design, Chiradeep Sen

All Theses

In engineering design research, function structures are used to represent the intended functionality of technical artifacts. Function structures are graph-based representations where the nodes are functions, or actions, and the edges are flows, or objects of those actions. For the consistent description of artifact functionality, multiple controlled vocabularies have been developed in previous research. The Functional Basis is one such vocabulary that provides for a set of verbs and a set of nouns, organized in the three-level hierarchy. This vocabulary is extensively studied in design research. Two major application of this vocabulary are the Design Repository, which is a web-base ...


A Priori Analysis Of Subgrid Scalar Phenomena And Mass Diffusion Vectors In Turbulent Hydrogen-Oxygen Flames, Justin Foster May 2009

A Priori Analysis Of Subgrid Scalar Phenomena And Mass Diffusion Vectors In Turbulent Hydrogen-Oxygen Flames, Justin Foster

All Theses

Direct Numerical Simulations (DNS) of high pressure, turbulent H2/O2 non-premixed flames employing real gas effects, detailed chemistry, multicomponent, differential, and cross diffusion are conducted. The results of these simulations are analyzed to provide important subgrid information relevant to Large Eddy Simulation (LES) of turbulent combustion. Subgrid filtered scalar dissipation and scalar variances, species concentrations, reaction rates, and flame temperature are presented as a function of mixture fraction. The analysis also includes a detailed comparison of the actual filtered mass flux vectors with their corresponding forms evaluated with the filtered primitive variables. The results show a reasonable correlation ...


Taxonomy Of Physical Prototypes: Structure And Validation, Ashwin Michaelraj May 2009

Taxonomy Of Physical Prototypes: Structure And Validation, Ashwin Michaelraj

All Theses

This thesis introduces a taxonomy of physical prototypes, and validates the proposed taxonomy by five different approaches. The proposed taxonomy is validated by, (i) checking the orthogonality of individual elements of the taxonomy, (ii) benchmarking the taxonomy with existing classifications of prototypes, (iii) demonstrating its utility by applying it to classify different prototypes, (iv) building a prototype database containing 35 different prototypes, and (v) consistency evaluation of the prototype database using a description logic based software called ProtŽgŽ.
The results indicate that the proposed taxonomy is capable of distinguishing prototypes with greater accuracy when compared to existing classifications. The orthogonality ...


Development Of A Falling Sphere Instrument For High-Resolution Neutral Wind Measurements In The Mesosphere And Lower Thermosphere, Arpan Shah May 2009

Development Of A Falling Sphere Instrument For High-Resolution Neutral Wind Measurements In The Mesosphere And Lower Thermosphere, Arpan Shah

All Theses

Passive falling spheres launched from small rockets have been used extensively in the past to measure the winds and densities in the mesosphere. In principle, the same technique can be extended to higher altitudes that cover the lower thermosphere, in addition to the mesosphere. The main difficulties are that accelerations decrease rapidly with height due to the decreasing atmospheric density and rigid spheres are required at higher altitudes, which implies larger mass and smaller accelerations. Accelerometers with broad dynamic range and high sensitivity are required for the measurements, but such devices are not readily available. We describe an instrumented falling ...