Engineering Commons^™

Prioritizing Offshore Vendor Selection Criteria For The North American Geospatial Industry, Simon Wolfgang Musaeus

Walden Dissertations and Doctoral Studies

The U.S. market for geospatial services totaled US $2.2 billion in 2010, representing 50% of the global market. Data-processing firms subcontract labor-intensive portions of data services to offshore providers in South and East Asia and Eastern Europe. In general, half of all offshore contracts fail within the first 5 years because one or more parties consider the relationship unsuccessful. Despite the high failure rates, no study has examined the offshore vendor selection process in the geospatial industry. The purpose of this study was to determine the list of key offshore vendor selection criteria and the efficacy of the analytic hierarchy …

The Past Present And Future Of The Ece Smart Kart, Issac Daniel

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Atomic Layer Deposition, Paul Kubicza

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Predictive Modeling Of Coupled Multi-Physics Systems: Ii. Illustrative Application To Reactor Physics, Dan Gabriel Cacuci, Madalina Corina Badea

Faculty Publications

This work presents paradigm applications to reactor physics of the innovative mathematical methodology for "predictive modeling of coupled multi-physics systems (PMCMPS)" developed by Cacuci (2014). This methodology enables the assimilation of experimental and computational information and computes optimally predicted responses and model parameters with reduced predicted uncertainties, taking fully into account the coupling terms between the multi-physics systems, but using only the computational resources that would be needed to perform predictive modeling on each system separately. The paradigm examples presented in this work are based on a simple neutron diffusion model, chosen so as to enable closed-form solutions with clear …

Passive Sampling Methods For Contaminated Sediments: Scientific Rationale Supporting Use Of Freely Dissolved Concentrations, Philipp Mayer, Thomas F. Parkerton, Rachel G. Adams, John G. Cargill, Jay Gan, Todd Gouin, Philip M. Gschwend, Steven B. Hawthorne, Paul Helm, Gesine Witt, Jing You, Beate I. Escher

Civil and Environmental Engineering Faculty Works

Passive sampling methods (PSMs) allow the quantification of the freely dissolved concentration (Cfree ) of an organic contaminant even in complex matrices such as sediments. Cfree is directly related to a contaminant's chemical activity, which drives spontaneous processes including diffusive uptake into benthic organisms and exchange with the overlying water column. Consequently, Cfree provides a more relevant dose metric than total sediment concentration. Recent developments in PSMs have significantly improved our ability to reliably measure even very low levels of Cfree . Application of PSMs in sediments is preferably conducted in the equilibrium regime, where freely dissolved concentrations in the …

Survey On Securing Data Storage In The Cloud, Lei Huang

Computer Science Faculty Works

Cloud Computing has become a well-known primitive nowadays; many researchers and companies are embracing this fascinating technology with feverish haste. In the meantime, security and privacy challenges are brought forward while the number of cloud storage user increases expeditiously. In this work, we conduct an in-depth survey on recent research activities of cloud storage security in association with cloud computing. After an overview of the cloud storage system and its security problem, we focus on the key security requirement triad, i.e., data integrity, data confidentiality, and availability. For each of the three security objectives, we discuss the new unique challenges …

Creating Learning Through Service Opportunities For Engineering Students: Lessons Learned From A Primarily Undergraduate Liberal Arts University, Matthew Siniawski, Jose A. Saez, Jeremy Pal, Sandra Luca

Mechanical Engineering Faculty Works

The challenge of creating impactful and long-lasting service opportunities for engineering students lies in how to best implement programs in the unique setting of each academic institution. This paper presents a critical reflection of two different models of learning through service opportunities for engineering students that have evolved over the past six years at Loyola Marymount University. In particular, we highlight the history and lessons learned from four different case studies involving both extra-curricular international service projects and course-based service-learning opportunities for engineering students. Overall lessons learned that emerged from our experience include: 1) Students should receive course credit for …

A User-Oriented Network Forensic Analyser: The Design Of A High-Level Protocol Analyser, D Joy, F Li, N L. Clarke, S M. Furnell

Australian Digital Forensics Conference

Network forensics is becoming an increasingly important tool in the investigation of cyber and computer-assisted crimes. Unfortunately, whilst much effort has been undertaken in developing computer forensic file system analysers (e.g. Encase and FTK), such focus has not been given to Network Forensic Analysis Tools (NFATs). The single biggest barrier to effective NFATs is the handling of large volumes of low-level traffic and being able to exact and interpret forensic artefacts and their context – for example, being able extract and render application-level objects (such as emails, web pages and documents) from the low-level TCP/IP traffic but also understand how …

Bio-Inspired Flow Sensing For Underwater Guidance And Navigation, Levi Devries

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Stream-dwelling fish and aquatic mammals have an innate ability to navigate often-tumultuous environments with impressive precision, a highly desirable trait for underwater vehicle applications. For example, trout use their lateral line to sense vortices shed by an upstream obstacle and slalom between the vortices to reduce energy expenditure compared to free-stream swimming [3]. Moreover, harbor seals can use their whiskers to follow the trail of flow disturbances created in the wake of an object that has passed minutes before [4]. Recent developments in materials science have produced sensors that can measure local flow velocity similar to seal whiskers, and integration …

Optimal Design Of Geothermal Power Plants, Joshua Clarke

Theses and Dissertations

The optimal design of geothermal power plants across the entire spectrum of meaningful geothermal brine temperatures and climates is investigated, while accounting for vital real-world constraints that are typically ignored in the existing literature. The constrained design space of both double-flash and binary geothermal power plants is visualized, and it is seen that inclusion of real-world constraints is vital to determining the optimal feasible design of a geothermal power plant. The effect of varying condenser temperature on optimum plant performance and optimal design specifications is analyzed. It is shown that condenser temperature has a significant effect on optimal plant design …

Experimental Development Of Advanced Air Filtration Media Based On Electrospun Polymer Fibers, Negar Ghochaghi

Theses and Dissertations

Electrospinning is a process by which polymer fibers can be produced using an electrostatically driven fluid jet. Electrospun fibers can be produced at the micro- or nano-scale and are, therefore, very promising for air filtration applications. However, because electrospun fibers are electrically charged, it is difficult to control the morphology of filtration media. Fiber size, alignment and uniformity are very important factors that affect filter performance. The focus of this project is to understand the relationship between filter morphology and performance and to develop new methods to create filtration media with optimum morphology.

This study is divided into three focus …

Electron – Phonon Interaction In Multiple Channel Gan Based Hfets: Heat Management Optimization, Romualdo A. Ferreyra

Theses and Dissertations

New power applications for managing increasingly higher power levels require that more heat be removed from the power transistor channel. Conventional treatments for heat dissipation do not take into account the conversion of excess electron energy into longitudinal optical (LO) phonons, whose associated heat is stored in the channel unless such LO phonons decay into longitudinal acoustic (LA) phonons via a Ridley path. A two dimensional electron gas (2DEG) density of ~5×10¹²cm^-2 in the channel results in a strong plasmon–LO phonon coupling (resonance) and a minimum LO phonon lifetime is experimentally observed, implying fast heat removal from …

Tissue Engineering Scaffold Fabrication And Processing Techniques To Improve Cellular Infiltration, Casey Grey

Theses and Dissertations

Electrospinning is a technique used to generate scaffolds composed of nano- to micron-sized fibers for use in tissue engineering. This technology possesses several key weaknesses that prevent it from adoption into the clinical treatment regime. One major weakness is the lack of porosity exhibited in most electrospun scaffolds, preventing cellular infiltration and thus hosts tissue integration. Another weakness seen in the field is the inability to physically cut electrospun scaffolds in the frontal plane for subsequent microscopic analysis (current electrospun scaffold analysis is limited to sectioning in the cross-sectional plane). Given this it becomes extremely difficult to associate spatial scaffold …

A Practical Tool For The Determination Of Surface Stresses In Railroad Bearings With Different Contact Geometries And Load Conditions Using Finite Element Analysis, Michael A. Mason

Theses and Dissertations

The connection between contact geometry and fatigue in tapered roller bearings utilized in the railroad environment is still of interest. Roller bearings for railroad applications are typically precision ground with crowned contact geometries to prevent edge loading of components. This normally results in completely elastic Hertzian contact stresses under standard railcar loads. However, under extreme load conditions, detrimental edge loading has been known to occur. It is proposed to develop a tool, using finite element analysis, that can be utilized to optimize complex raceway crown geometries for severe applications.

A successful implementation of this tool is presented and validated using …

Modern Statistical Methods And Uncertainty Quantification For Evaluating Reliability Of Nondestructive Evaluation Systems, Jeremy Scott Knopp

Browse all Theses and Dissertations

The reliability of Nondestructive Evaluation (NDE) is an important input for risk analysis for sustainment of aging infrastructure. Reliability has typically been quantified via probability of detection (POD) studies. There are three problems with POD modeling methodologies provided in the most recent guidance on the subject:

1) Current models do not estimate the extremes of a POD curve very well because of the assumption that the POD curve approaches zero as flaw size goes to zero, and the POD curve approaches one as the flaw size goes to infinity.

2) The existing 2-parameter logit/probit models can be misused since there …

Evaluation And Application Of Lte, Dvb, And Dab Signals Of Opportunity For Passive Bistatic Sar Imaging, Aaron S. Evers

Browse all Theses and Dissertations

Due to the many advantages of passive radar and ubiquity of commercial broadcast transmitters, interest in passive bistatic radar (PBR) applications has continued to grow. More specifically, sources studying commercial orthogonal frequency division multiplexing (OFDM) waveforms for passive bistatic synthetic aperture radar (SAR) imaging have become more common. This work evaluates and applies long term evolution (LTE), digital video broadcast (DVB), and digital audio broadcast (DAB) signals of opportunity for passive bistatic SAR imaging.

First, implications of the structure and properties of each of the signal of opportunity's transmitted waveform are characterized by examining the waveform's self- and cross-ambiguity functions …

Fragment Association Matching Enhancement (Fame) On A Video Tracker, Andrew Johnson

Browse all Theses and Dissertations

In the field of surveillance, algorithms are developed to extract meaningful information out of a video feed captured via a camera. One type of algorithm used in the field of surveillance is a tracking algorithm. A tracking algorithm allows a user to watch the movement of an object in the camera's field of view. The tracker used in this thesis research is a feature aided tracker (FAT). The FAT uses both features and kinematics to generate tracks. However, camera movement will affect the tracker's ability to accurately track an object which poses a problem to the tracker. Specifically, the camera …

A Validation Study Of Sc/Tetra Cfd Code, Hongtao Yu

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The goal of this study is to validate the accuracy of the SC/Tetra CFD code by modeling four cases: a 2D zero pressure gradient flat plate, an axisymmetric separated boundary layer, flow over an NACA 0012 airfoil, and flow over an NACA 4412 airfoil trailing edge separation. The results will be compared to experimental data and CFL3D results. This study also investigates the sensitivity of SC/Tetra results to different set up details such as mesh resolution, turbulence model, and under-relaxation settings. Automation using the Visual Basic programming language was used to vary these set up details and efficiently process a …

Novel Devices And Components For Thz Systems, John Raymond Middendorf

Browse all Theses and Dissertations

Since the first demonstration of the generation of terahertz (THz) pulses from photoconductive (PC) antennas, research has pushed toward the development of smaller, cost efficient, and faster THz systems. This dissertation presents the work accomplished in order to realize these more practical terahertz (THz) photoconductive (PC) systems.

First, this work will present a novel ErAs:GaAs photoconductive switch used to make a THz source excited by 1550 nm laser pulses. It will be shown that the excitation process taking place in the material relies on extrinsic (rather than intrinsic) photoconductivity. Then, several experiments will be presented that aim to improve the …

Impact Of Sar Image Formation Quality On Target Separability, Cody A. Lawyer

Browse all Theses and Dissertations

The polar format algorithm (PFA) allows the use of computationally efficient fast Fourier transforms in synthetic aperture radar (SAR) image formation, but introduces phase errors when making the far-field approximations that facilitate this approach. The phase errors cause spatially variant distortion and defocus in the formed image. These effects may complicate target recognition applications. To limit the impact of defocus, scene size is usually limited such that the maximum quadratic phase error within an image falls below some threshold. This thesis looks at how distortion and defocus affects the classification of targets, with the hope of developing an application-driven scene …

Analysis Of A Fuel Cell Combustor In A Solid Oxide Fuel Cell Hybrid Gas Turbine Power System For Aerospace Application, Ryan R. Sinnamon

Browse all Theses and Dissertations

Over the last few years, fuel cell technology has significantly advanced and has become a mode of clean power generation for many engineering applications. Currently the dominant application for fuel cell technology is with stationary power generation. Very little has been published for applications on mobile platforms, such as unmanned aerial vehicles. With unmanned aerial vehicles being used more frequently for national defense and reconnaissance, there is a need for a more efficiency, longer endurance power system that can support the increased electrical loads onboard. It has already been proven by others that fuel cell gas turbine hybrid systems can …

Influence Of Curved Geometries On The Fatigue Life Of Laser Peened Components, Anoop Vasu

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Generating compressive residual stresses at the critical stress locations can prevent or delay structural component failure. Laser peening is a well-known method for inducing compressive residual stresses. The plastic deformation created by the planar shock waves near the surface regions is the major cause for the generation of compressive residual stresses. Apart from the planar waves, release waves at the border of impact are generated that act against the plastic deformation created by planar waves. This decrease of plastic deformation reduces the compressive residual stress generated near the surface regions of peened components. Laser peening of curved geometries creates compressive …

Development And Application Of An Analyst Process Model For A Search Task Scenario, Hendrickson K. Karl

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A key intelligence analyst role in open source search is the transformation of data into understanding. Better comprehension is needed of how new tools impact the analyst search process. The use of function analysis, heuristic analysis, and a usability study combine to provide the basis for developing an analyst process model, which affords the researcher with a structure to measure the impact of tools and expertise in performing a search task. The experiment utilized representative analyst scenario tasks in comparing baseline tools with the Geospatial Open Search Toolkit (GOST). The results show error rates increase when using a new toolset …

Relating Microstructure To Process Variables In Beam-Based Additive Manufacturing Of Inconel 718, John Ryan Thompson

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The advancement of laser or electron beam-based additive manufacturing requires the ability to control solidification microstructure. Previous work combined analytical point source solutions and nonlinear thermal finite element analysis (FEA) to explore the effects of deposition process variables on Ti-6Al-4V solidification microstructure. The current work seeks to extend the approach to Inconel 718, with the addition of Cellular Automaton-Finite Element (CAFE) models. Numerical data from finite element results are extracted in order to calculate accurate melt pool geometry, thus leading to corresponding cooling rates and thermal gradients. The CAFE models are used to simulate grain grown and nucleation, providing a …

Study On The Vortex Wake Of An Airfoil Equipped With Flexible Trailing Edge Fringes, Zhengkai He

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With the inspiration of owl's silent flight, a traditional airfoil S833 equipped with flexible fringes on the trailing edge is investigated through numerical simulation and experiments in a wind tunnel. The newly constructed airfoil is modeled and numerically investigated. An incompressible, 2D and viscous flow solver in the Computational Fluid Dynamics (CFD) software FLUENT is utilized to conduct the numerical simulation on the vortex flow feature in the wake of the airfoil. A User Defined Function code was applied to generate the defined motion of flexible fringes. The effects of the flapping frequency of the fringe and the deformation pattern …

Hierarchical Porous Structures Functionalized With Silver Nanoparticles: Adaptation For Antibacterial Applications, Anil Kumar Karumuri

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For a large number of applications involving surface interactions, there is an ever growing demand for materials with high specific surface area (surface area to volume ratio). Porous materials and nanomaterials offer higher specific surface area (SSA) each with their respective advantages and disadvantages. This research program is focused on bringing the two approaches together to create truly "hierarchical" materials that combine advantages of both while minimizing their disadvantages. In this study, various carbon based porous geometries were fabricated by grafting carbon nanotubes (CNT) onto highly porous reticulated carbon foams. These structures were further modified by functionalizing metal nanoparticles such …

Two-Speed Control Of Compressors In Residentlial Air-Conditioning Systems, George Joseph Ramayya

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Residential air-conditioning systems pre-dominantly have single phase compressors and the new technology in use is Ultratech scroll compressors capable of running at partial and full capacity levels using electro-mechanical controls allowing for staged and more efficient operation based on system load conditions. This project is to look at electronic methods to obtain two-speed control to duplicate the Ultratech compressor and evaluate the performance of the control options. A triac control scheme is designed for worst case assuming maximum load conditions of compressor in an air-conditioning system. The control schemes are prototype tested on single phase motor and compressor motor for …

Imperfect Situation Analysis: Representing The Role Of Error And Uncertainty In Modeling, Simulation And Analysis, Victor Eaton Middleton

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Much of traditional modeling, simulation and analysis (MS&A) is supported by engineering models - deterministic, Newtonian physics-based representations of closed systems. Such approaches are not well-suited to represent the intricacies of human behavior. This research advocates and seeks to articulate the concept of a more human- centric approach to MS& A, one that better represents decision-making and other cognitive aspects of human behavior as well as it does physical activity.

It starts with a view of individuals and groups as complex adaptive systems, which are best represented using agent-based modeling. Representation of human behavior through intelligent agents incorporates models of …

Investigation Of Capabilities Of Observers In A Watch Window Study, Ositadimma Nnanna Eziolisa

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Due to an abundance of data and dynamic nature of tasks, challenges with information retrieval in surveillance and target identification tasks have risen in today's Intelligence, Surveillance, and Reconnaissance (ISR) community. In this study, two variables, Area of Coverage and Amount of Activity (AOC/ACT), are manipulated to study their effects on the number of Watch Windows an observer can monitor. This research describes the analyst's task model, and explains how the level of AOC/ACT and number of Watch Windows affects the analyst's cognitive load. Results showed a significant difference in performance and physiological indicators of workload between high AOC/ACT conditions …

Testing Of Two Novel Semi-Implicit Particle-In-Cell Techniques, Trenton J. Godar

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PIC (Particle-in-cell) modeling is a computational technique which functions by advancing computer particles through a spatial grid consisting of cells, on which can be placed electric and magnetic fields. This method has proven useful for simulating a wide range of plasmas and excels at yielding accurate and detailed results such as particle number densities, particle energies, particle currents, and electric potentials. However, the detailed results of a PIC simulation come at a substantial cost of computational requirement and the algorithm can be susceptible to numerical instabilities. As processors become faster and contain more cores, the computational expense of PIC simulations …