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Dislocation Dynamics Simulations Of Plasticity At Small Scales, Caizhi Zhou 2010 Iowa State University

Dislocation Dynamics Simulations Of Plasticity At Small Scales, Caizhi Zhou

Graduate Theses and Dissertations

As metallic structures and devices are being created on a dimension comparable to the length scales of the underlying dislocation microstructures, the mechanical properties of them change drastically. Since such small structures are increasingly common in modern technologies, there is an emergent need to understand the critical roles of elasticity, plasticity, and fracture in small structures. Dislocation dynamics (DD) simulations, in which the dislocations are the simulated entities, offer a way to extend length scales beyond those of atomistic simulations and the results from DD simulations can be directly compared with the micromechanical tests.

The primary objective of this research ...


Molecular Design Of Nanoparticle-Based Delivery Vehicles For Pneumonic Plague, Bret Daniel Ulery 2010 Iowa State University

Molecular Design Of Nanoparticle-Based Delivery Vehicles For Pneumonic Plague, Bret Daniel Ulery

Graduate Theses and Dissertations

The work described in this dissertation focuses on the design of polyanhydride nanoparticles that function as both adjuvants and long-term antigen delivery vehicles in order to improve vaccination, specifically for biodefense-related applications. Chapter 1 is an introduction into the threat of bioterrorism, polymer-based controlled delivery systems and challenges associated with vaccine design.

Chapter 2 is a detailed literature review of topics related to the research conducted in this dissertation. Areas covered include basic immunology, vaccine design, degradable polymer-based adjuvant engineering, plague (Yersinia pestis) biology, and vaccines that confer protection against plague.

Chapter 3 overviews the research objectives and the specific ...


Gpu Integration Into A Software Defined Radio Framework, Joel Gregory Millage 2010 Iowa State University

Gpu Integration Into A Software Defined Radio Framework, Joel Gregory Millage

Graduate Theses and Dissertations

Software Defined Radio (SDR) was brought about by moving processing done on specific hardware components to reconfigurable software. Hardware components like General Purpose Processors (GPPs), Digital Signal Processors (DSPs) and Field Programmable Gate Arrays (FPGAs) are used to make the software and hardware processing of the radio more portable and as efficient as possible. Graphics Processing Units (GPUs) designed years ago for video rendering, are now finding new uses in research. The parallel architecture provided by the GPU gives developers the ability to speed up the performance of computationally intense programs. An open source tool for SDR, Open Source Software ...


Ozone-Based Decolorization Of Food Colorants: Characterization And Application To Fruit Leather Recycling, Wenda Zhu 2010 Iowa State University

Ozone-Based Decolorization Of Food Colorants: Characterization And Application To Fruit Leather Recycling, Wenda Zhu

Graduate Theses and Dissertations

The commercial production of fruit leathers results in some material that is not to specification. Although this product remains edible and contains valuable ingredients such as fruit pulp, sugars and acidulates, it is not salable and its disposal is costly. Because these products are typically highly colored, recovery of fruit leather for recycling into the product requires colorant removal to avoid an unappetizing brownish color from the mixture of colorants. This research introduces a novel approach utilizing ozonation for color removal. The treatment was first applied to pure solutions of the commonly used food colorants 2-naphthalenesulfonic acid (Red 40), tartrazine ...


A Multi-Modal Interface For Road Planning Tasks Using Vision, Haptics And Sound, Matthew Charles Newcomb 2010 Iowa State University

A Multi-Modal Interface For Road Planning Tasks Using Vision, Haptics And Sound, Matthew Charles Newcomb

Graduate Theses and Dissertations

The planning of transportation infrastructure requires analyzing many different types of geo-spatial information in the form of maps. Displaying too many of these maps at the same time can lead to visual clutter or information overload, which results in sub-optimal effectiveness. Multimodal interfaces (MMIs) try to address this visual overload and improve the user's interaction with large amounts of data by combining several sensory modalities. Previous research into MMIs seems to indicate that using multiple sensory modalities leads to more efficient human-computer interactions when used properly.

The motivation from this previous work has lead to the creation of this ...


Issures In Discontinuous High-Order Methods: Broadband Wave Computation And Viscous Boundary Layer Resolution, Yi Li 2010 Iowa State University

Issures In Discontinuous High-Order Methods: Broadband Wave Computation And Viscous Boundary Layer Resolution, Yi Li

Graduate Theses and Dissertations

A new discontinuous formulation named Correction Procedure via Reconstruction (CPR) was developed for conservation laws. CPR is an efficient nodal differential formulation unifying the discontinuous Galerkin (DG), spectral volume (SV) and spectral difference (SD) methods, is easy to implement. In this thesis, we deal with two issues: the efficient computation of broadband waves, and the proper resolution of a viscous boundary layer with the high-order CPR method.

A hybrid discontinuous space including polynomial and Fourier bases is employed in the CPR formulation in order to compute broad-band waves. The polynomial bases are used to achieve a certain order of accuracy ...


Static And Dynamic Nonlinearity Compensation Techniques For High Performance Current-Steering Digital-To-Analog Converters, Tao Zeng 2010 Iowa State University

Static And Dynamic Nonlinearity Compensation Techniques For High Performance Current-Steering Digital-To-Analog Converters, Tao Zeng

Graduate Theses and Dissertations

High-speed high-accuracy digital-to-analog converters (DACs) are the crucial building blocks for many signal processing and telecommunication systems. The current-steering architecture is extensively used for these applications. With different decoding schemes--binary-weighted, unary-coded, and segment-coded, current-steering DACs are realized by groups of matched current sources. Their performance is limited by many nonlinear mechanisms such as random mismatch errors, gradient effect, code and voltage dependence of finite output impedance, nonlinear settling time, charge injection, and switch timing errors. In this thesis, two nonlinearity compensation techniques are presented to improve the overall performance of the current-steering DACs.

The first design technique is a novel ...


Performance Of A Pilot Scale Biomass Gasification And Producer Gas Combustion System Using Feedstock With Controlled Nitrogen Content, Sharan Sethuraman 2010 Iowa State University

Performance Of A Pilot Scale Biomass Gasification And Producer Gas Combustion System Using Feedstock With Controlled Nitrogen Content, Sharan Sethuraman

Graduate Theses and Dissertations

This study is focused on the effects of nitrogen content in biomass feedstock on the producer gas composition and the flue gas NOx emissions from a pilot-scale gasification and combustion system. Biomass gasification has the potential to produce carbon negative

energy by using renewable resources. The greenhouse gases emitted by burning fossil fuels have to be reduced, and biomass gasification is one of the means to achieving this. When the biomass-derived gas is burned, NOx emissions are a critical factor that can limit the use of the system. The government regulations limit the amount of NOx that can be emitted ...


Sensor Augmented Large Interactive Surfaces, Prasad Ramanahally Siddalinga 2010 Iowa State University

Sensor Augmented Large Interactive Surfaces, Prasad Ramanahally Siddalinga

Graduate Theses and Dissertations

Large interactive surfaces enable effective multi-user collaboration, but a majority of the current multi-touch systems are not truly multi-user. In this work we present a novel sensor-based approach for both user identification around a touch table and integration of unique gestures above the table. The work proposes the criteria for a successful and robust user identification system. The Cricket sensor based user identification system is integrated with an open source gesture recognition system "Sparsh-UI" to enable rapid multi-touch application development. Finally we evaluate the Cricket-based algorithm with contemporary multi-user, multi-touch systems and describe the various interaction affordances provided by the ...


A Graph Oriented Approach For Network Forensic Analysis, Wei Wang 2010 Iowa State University

A Graph Oriented Approach For Network Forensic Analysis, Wei Wang

Graduate Theses and Dissertations

Network forensic analysis is a process that analyzes intrusion evidence captured from networked environment to identify suspicious entities and stepwise actions in an attack scenario. Unfortunately, the overwhelming amount and low quality of output from security sensors make it difficult for analysts to obtain a succinct high-level view of complex multi-stage intrusions.

This dissertation presents a novel graph based network forensic analysis system. The evidence graph model provides an intuitive representation of collected evidence as well as the foundation for forensic analysis. Based on the evidence graph, we develop a set of analysis components in a hierarchical reasoning framework. Local ...


Improving Particle Swarm Optimization Path Planning Through Inclusion Of Flight Mechanics, Joseph Scott Holub 2010 Iowa State University

Improving Particle Swarm Optimization Path Planning Through Inclusion Of Flight Mechanics, Joseph Scott Holub

Graduate Theses and Dissertations

Military engagements are continuing the movement toward automated and unmanned vehicles for a variety of simple and complex tasks. This allows humans to stay away from dangerous situations and use their skills for more difficult tasks. One important piece of this strategy is the use of automated path planners for unmanned aerial vehicles (UAVs). Current UAV operation requires multiple individuals to control a single plane, tying up important human resources. Often paths are planned by creating waypoints for a vehicle to fly through, with the intention of doing reconnaissance while avoiding as much danger to the plane as possible. Path ...


Analysis And Testing Of A New Prototype Power Transmission Structure And An Alternative Design Approach For Longitudinal Loads, Casey Vaughn Faber 2010 Iowa State University

Analysis And Testing Of A New Prototype Power Transmission Structure And An Alternative Design Approach For Longitudinal Loads, Casey Vaughn Faber

Graduate Theses and Dissertations

As the power transmission infrastructure is expanded, structures that can be rapidly constructed and are cost efficient, reliable, and sustainable will be needed. A prototype power transmission structure designed to address the issue of cascading collapse, be efficiently constructed, and be easily repaired in the event of a catastrophic load such as a transmission line break was investigated. This structure utilizes post-tensioning and a joint to allow for large deflections. The specially designed joint isolates inelastic deformation to structural fuses that are inexpensive and easy to replace. The structure's high deflection capacity could isolate damage from extreme loads to ...


A Low-Cost, Connection Aware, Load-Balancing Solution For Distributing Gigabit Ethernet Traffic Between Two Intrusion Detection Systems, Adam Christopher Jackson 2010 Iowa State University

A Low-Cost, Connection Aware, Load-Balancing Solution For Distributing Gigabit Ethernet Traffic Between Two Intrusion Detection Systems, Adam Christopher Jackson

Graduate Theses and Dissertations

In today's world of computer networking, Gigabit Ethernet is quickly becoming the norm for connectivity in computer networks. The ease of access to information on these networks leads to new information being made available daily. Rises in both malicious users and malicious network traffic increase the need for intrusion detection systems to monitor network traffic. However, intrusion detection systems capable of processing network traffic at the rate necessary for Gigabit Ethernet are typically expensive. An alternative to purchasing one of these systems is to use multiple, cheaper intrusion detection systems and run them in parallel. This requires that traffic ...


Efficient Methods For Solving Boundary Integral Equation In Diffusive Scalar Problem And Eddy Current Nondestructive Evaluation, Ming Yang 2010 Iowa State University

Efficient Methods For Solving Boundary Integral Equation In Diffusive Scalar Problem And Eddy Current Nondestructive Evaluation, Ming Yang

Graduate Theses and Dissertations

Eddy current nondestructive evaluation (NDE) of airframe structures involves the detection of electromagnetic field irregularities due to non-conducting inhomogeneities in an electrically conducting material. Usually, the eddy current NDE problem can be formulated by the boundary integral equations (BIE) and discretized into matrix equations by the method of moments (MoM) or the boundary element method (BEM). The fast multipole method (FMM) is a well-established and effective method for accelerating numerical solutions of the matrix equations. Accelerated by the FMM, the BIE method can now solve large-scale electromagnetic wave propagation and diffusion problems. The traditional BIE method requires O(N2 ...


Discovering Patterns In A Survey Of Secondary Injuries Due To Agricultural Assistive Technology, Yanjun Shi 2010 Iowa State University

Discovering Patterns In A Survey Of Secondary Injuries Due To Agricultural Assistive Technology, Yanjun Shi

Graduate Theses and Dissertations

The research is motivated by the need for hazard assessment in agriculture field. A small and highly-imbalanced dataset, in which negative instances heavily outnumber positive instances, is derived from a survey of secondary injuries induced by implementation of agriculture assistive technology which assists farmers with injuries or disabilities to continue farm-related work. Three data mining approaches are applied to the imbalanced dataset in order to discover patterns contributing to secondary injuries.

All of patterns discovered by the three approaches are compared according to three evaluation measurements: support, confidence and lift, and potentially most interesting patterns are found. Compared to graphical ...


The Yield Strength And Flow Stress Anomaly In B2 Yttrium Copper, Andrew Todd Becker 2010 Iowa State University

The Yield Strength And Flow Stress Anomaly In B2 Yttrium Copper, Andrew Todd Becker

Graduate Theses and Dissertations

The apparent yield strength anomaly in the B2 YCu intermetallic compound is shown not to be a yield point anomaly at all, but rather a phenomenon resulting from the work hardening behavior in YCu, which was found to rise with rising temperature and to drop with increases in strain rate. This effect is shown to occur over temperature ranges where YCu has negative strain rate sensitivity, result in dynamic strain ageing behavior, and the effect is shown to be irreversible when the testing temperature is changed. Neutron diffraction experiments utilizing SMARTS and HIPPO show the evolution of texture and the ...


Seismic Performance Of An I-Girder To Inverted-T Bent Cap Bridge Connection, Richard Manning Snyder 2010 Iowa State University

Seismic Performance Of An I-Girder To Inverted-T Bent Cap Bridge Connection, Richard Manning Snyder

Graduate Theses and Dissertations

This thesis represents a portion of the research conducted as part of an investigation for the California Department of Transportation (Caltrans) regarding the seismic response and overall moment capacity of precast I-girder to inverted-T bent cap bridge connections for seismic applications. The current design practice, as outlined by Caltrans' Seismic Design Criteria, assumes that the connection between the precast I-girders and the inverted-T bent cap will degrade in a seismic event and shall therefore be designed as a pinned connection, making the precast girder option for seismic bridges inefficient. A prototype I-girder to inverted-T bent cap bridge and a 50 ...


A Comrehensive Model Study For Flash Nanoprecipitation: Computational Fluid Dynamics, Micro- Particle Image Velocimetry, And Population Balance Modeling, Janine Chungyin Cheng 2010 Iowa State University

A Comrehensive Model Study For Flash Nanoprecipitation: Computational Fluid Dynamics, Micro- Particle Image Velocimetry, And Population Balance Modeling, Janine Chungyin Cheng

Graduate Theses and Dissertations

A model study has been conducted for Flash Nanoprecipitation(FNP)) - a novel approach to produce functional nanoparticles. A mixing study has been conducted in a custom-designed microscale multi-inlet vortex reactor (MIVR) and a scalar mixing model was validated against experimental data. A microPIV experiment was conducted to further validate the turbulent model. A population balance equation (PBE) has been proposed to model the FNP process. It was furthermore, integrated into a computational fluid dynamics (CFD) simulation of to yield conditions comparable to the real experimental settings. In coping with the complicated aggregation model in the CFD code, a new numerical ...


Measurement Of Soil-Tire Interface Stresses, Jonathan Tate Roth 2010 Iowa State University

Measurement Of Soil-Tire Interface Stresses, Jonathan Tate Roth

Graduate Theses and Dissertations

Agricultural energy usage is an important topic among agricultural industry producers, manufacturers and regulators. Zoz and Grisso (2003) stated that prior research shows between 20 and 55% of tractor energy is lost at the soil-tire interface. This transfer of power between axle and drawbar has been identified as one of the greatest inefficiencies in agricultural field operations. Understanding the stresses at the soil-tire interface would provide insight into the current state of tire traction development, data for soil-tire interface discrete and finite-element models, and information for future tire designs.

This paper presents a measurement system to quantify the shear and ...


Supply Chain Models For An Ethanol And Distillers Grains Producer And A Distillers Grains-Based Feed Producer, Shi Peng 2010 Iowa State University

Supply Chain Models For An Ethanol And Distillers Grains Producer And A Distillers Grains-Based Feed Producer, Shi Peng

Graduate Theses and Dissertations

In recent years, there have been substantial interests in the joint production of ethanol and distillers grains (E&DG) from corn. At the same time, there have been corresponding increases in the production of animal feed based on distillers grains (DG). Under such circumstances, ethanol and DG are produced by an E&DG producer, and DG serves as input to feed production by a feed producer.The objective of this paper is to study the strategies of both producers in different models in order to maximize their own profit with more ethanol produced by consuming more DG in the feed ...


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