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Articles 91561 - 91590 of 197988

Full-Text Articles in Engineering

Remote Sensing And Localization Of Smart Rocks With Orientation-Controlled Magnets For Real-Time Monitoring Of Bridge Scour And Riprap Effectiveness, Yan Tang Jan 2017

Remote Sensing And Localization Of Smart Rocks With Orientation-Controlled Magnets For Real-Time Monitoring Of Bridge Scour And Riprap Effectiveness, Yan Tang

Doctoral Dissertations

"This study aims to develop and implement a novel smart rock technology for real-time monitoring of the maximum scour depth and the effectiveness of riprap mitigation measures. A smart rock is one or more stacked magnets encased in concrete that can automatically roll to the deepest point of a scour hole around a bridge pier and provide its location through remote measurement over time. Once integrated into a riprap measure, the smart rock moves together with natural rocks and is thus a potential indicator of the effectiveness of the riprap measure. Therefore, the localization and movement of smart rocks were …


Attitudes Towards Face-To-Face Meetings In Virtual Engineering Teams: Perceptions From A Survey Of Defense Projects, Lawrence R. Blenke, Abhijit Gosavi, William Daughton Jan 2017

Attitudes Towards Face-To-Face Meetings In Virtual Engineering Teams: Perceptions From A Survey Of Defense Projects, Lawrence R. Blenke, Abhijit Gosavi, William Daughton

Engineering Management and Systems Engineering Faculty Research & Creative Works

Modes of communication used in virtual defense projects have changed dramatically over the years with tools such as email and video-conferencing dominating face-to-face (FTF) meetings. We conducted a survey at a defense firm with an aim to test current attitudes towards FTF meetings – with respect to significant problems faced, project success, transfer of technical requirements, preference for FTF vis-à-vis virtual meetings, differences between virtual and co-located environments, criticality of various forms of communication, and whether FTF meetings were scheduled as often as desired. Our survey participants, about one hundred in number, were experienced engineers, technicians, and program managers – …


A Practical Approach To Evaluating The Economic And Technical Feasibility Of Led Luminaires, Sean M. Schmidt, Suzanna Long Jan 2017

A Practical Approach To Evaluating The Economic And Technical Feasibility Of Led Luminaires, Sean M. Schmidt, Suzanna Long

Engineering Management and Systems Engineering Faculty Research & Creative Works

LED roadway luminaires are currently under consideration for widespread implementation with departments of transportation, facilities managers, and city planners. This research focuses on a case study in Missouri and presents relevant research findings calculated by the authors as part of a project funded by the Missouri Department of Transportation. Although high-pressure sodium (HPS) luminaires have been the standard product for roadway illumination, advances in LED technologies have led many departments of transportation to consider them as viable options along state routes. For this case study, pilot sites were developed across the state of Missouri in sites assessed as moderately busy, …


Generating A Normalized Database Using Class Normalization, Daniel Sushil Sudhindaran Jan 2017

Generating A Normalized Database Using Class Normalization, Daniel Sushil Sudhindaran

UNF Graduate Theses and Dissertations

Relational databases are the most popular databases used by enterprise applications to store persistent data to this day. It gives a lot of flexibility and efficiency. A process called database normalization helps make sure that the database is free from redundancies and update anomalies. In a Database-First approach to software development, the database is designed first, and then an Object-Relational Mapping (ORM) tool is used to generate the programming classes (data layer) to interact with the database. Finally, the business logic code is written to interact with the data layer to persist the business data to the database. However, in …


Security Analysis Of Ecc Based Protocols, Chanchal Khatwani Jan 2017

Security Analysis Of Ecc Based Protocols, Chanchal Khatwani

UNF Graduate Theses and Dissertations

Elliptic curve cryptography (ECC) is extensively used in various multifactor authentication protocols. In this work, various recent ECC based authentication and key exchange protocols are subjected to threat modeling and static analysis to detect vulnerabilities, and to enhance them to be more secure against threats. This work demonstrates how currently used ECC based protocols are vulnerable to attacks. If protocols are vulnerable, damages could include critical data loss and elevated privacy concerns. The protocols considered in thiswork differ in their usage of security factors (e.g. passwords, pins, and biometrics), encryption and timestamps. The threatmodel considers various kinds of attacks including …


Biometric Encryption System For Increased Security, Ranjith Jayapal Jan 2017

Biometric Encryption System For Increased Security, Ranjith Jayapal

UNF Graduate Theses and Dissertations

Security is very important in present day life. In this highly-interconnected world, most of our daily activities are computer based, and the data transactions are protected by passwords. These passwords identify various entities such as bank accounts, mobile phones, etc. People might reuse the same password, or passwords related to an individual that can lead to attacks. Indeed, remembering several passwords can become a tedious task. Biometrics is a science that measures an individual’s physical characteristics in a unique way. Thus, biometrics serves as a method to replace the cumbersome use of complex passwords. Our research uses the features of …


Enhancing The Existing Microscopic Simulation Modeling Practice For Express Lane Facilities, Kelvin S. Machumu Jan 2017

Enhancing The Existing Microscopic Simulation Modeling Practice For Express Lane Facilities, Kelvin S. Machumu

UNF Graduate Theses and Dissertations

The implementation of managed lanes (MLs), also known as dynamically priced express lanes, to improve freeway traffic flow and personal throughput is on the rise. Congestion pricing is increasingly becoming a common strategy for congestion management, often requiring microscopic simulation during both planning and operational stages. VISSIM is a recognized microscopic simulation software used for analyzing the performance of managed lanes (MLs). This thesis addressed two important microscopic simulation issues that affect the evaluation results of MLs.

One of the microscopic simulation issues that has not yet been addressed by previous studies is the required minimum managed lane routing decision …


Degradation Resistant Surface Enhanced Raman Spectroscopy Substrates, Ryan D. Scherzer Jan 2017

Degradation Resistant Surface Enhanced Raman Spectroscopy Substrates, Ryan D. Scherzer

UNF Graduate Theses and Dissertations

Raman spectroscopy is employed by NASA, and many others, to detect trace amounts of substances. Unfortunately, the Raman signal is generally too weak to detect when very small, but non-trivial, amounts of molecules are present. One way around this weak signal is to use surface enhanced Raman spectroscopy (SERS).

When used as substrates for SERS, metallic nanorods grown using physical vapor deposition (PVD) provide a large enhancement factor to the Raman signal, as much as 1012. However, Silver (Ag) nanorods that give high enhancement suffer from rapid degradation as a function of time and exposure to harsh environment. …


The Effect Of Corrosion Defects On The Failure Of Oil And Gas Transmission Pipelines: A Finite Element Modeling Study, Jennet Orasheva Jan 2017

The Effect Of Corrosion Defects On The Failure Of Oil And Gas Transmission Pipelines: A Finite Element Modeling Study, Jennet Orasheva

UNF Graduate Theses and Dissertations

The transportation of oil and gas and their products through the pipelines is a safe and economically efficient way, when compared with other methods of transportation, such as tankers, railroad, trucks, etc. Although pipelines are usually well-designed, during construction and later in service, pipelines are subjected to a variety of risks. Eventually, some sections may experience corrosion which can affect the integrity of pipeline, which poses a risk in high-pressure operations. Specifically, in pipelines with long history of operation, the size and location of the corrosion defects need to be determined so that pressure levels can be kept at safe …


An Empirical Investigation Of Collaborative Web Search Tool On Novice's Query Behavior, Mareh Fakhir Al-Sammarraie Jan 2017

An Empirical Investigation Of Collaborative Web Search Tool On Novice's Query Behavior, Mareh Fakhir Al-Sammarraie

UNF Graduate Theses and Dissertations

In the past decade, research efforts dedicated to studying the process of collaborative web search have been on the rise. Yet, a limited number of studies have examined the impact of collaborative information search processes on novices’ query behaviors. Studying and analyzing factors that influence web search behaviors, specifically users’ patterns of queries when using collaborative search systems can help with making query suggestions for group users. Improvements in user query behaviors and system query suggestions help in reducing search time and increasing query success rates for novices.

This thesis investigates the influence of collaboration between experts and novices as …


Empirical Evaluation Of Cloud Iaas Platforms Using System-Level Benchmarks, Niharika Deval Jan 2017

Empirical Evaluation Of Cloud Iaas Platforms Using System-Level Benchmarks, Niharika Deval

UNF Graduate Theses and Dissertations

Cloud Computing is an emerging paradigm in the field of computing where scalable IT enabled capabilities are delivered ‘as-a-service’ using Internet technology. The Cloud industry adopted three basic types of computing service models based on software level abstraction: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS). Infrastructure-as-a-Service allows customers to outsource fundamental computing resources such as servers, networking, storage, as well as services where the provider owns and manages the entire infrastructure. This allows customers to only pay for the resources they consume. In a fast-growing IaaS market with multiple cloud platforms offering IaaS services, the user's decision on the selection …


Performance Analysis On Free-Piston Linear Expander, Furkan Kodakoglu Jan 2017

Performance Analysis On Free-Piston Linear Expander, Furkan Kodakoglu

UNF Graduate Theses and Dissertations

The growing global demand for energy and environmental implications have created a need to further develop the current energy generation technologies (solar, wind, geothermal, etc.). Recovering energy from low grade energy sources such as waste heat is one of the methods for improving the performance of thermodynamic cycles. The objective of this work was to achieve long-term steady state operation of a Free-Piston Linear Expander (FPLE) and to compare the FPLE with the currently existing expander types for use in low temperature energy recovery systems. A previously designed FPLE with a single piston, two chambers, and linear alternator was studied …


Performance Evaluation Of Hadoop Based Big Data Applications With Hibench Benchmarking Tool On Iaas Cloud Platforms, Karthika Muthiah Ms. Jan 2017

Performance Evaluation Of Hadoop Based Big Data Applications With Hibench Benchmarking Tool On Iaas Cloud Platforms, Karthika Muthiah Ms.

UNF Graduate Theses and Dissertations

Cloud computing is a computing paradigm where large numbers of devices are connected through networks that provide a dynamically scalable infrastructure for applications, data and storage. Currently, many businesses, from small scale to big companies and industries, are changing their operations to utilize cloud services because cloud platforms could increase company’s growth through process efficiency and reduction in information technology spending [Coles16]. Companies are relying on cloud platforms like Amazon Web Services, Google Compute Engine, and Microsoft Azure, etc., for their business development.

Due to the emergence of new technologies, devices, and communications, the amount of data produced is growing …


Strength Property Variability In Microbial Induced Calcite Precipitation Soils, Jacob Fuller Jan 2017

Strength Property Variability In Microbial Induced Calcite Precipitation Soils, Jacob Fuller

UNF Graduate Theses and Dissertations

Microbial Induced Calcite Precipitation (MICP) is an attractive alternative for a variety geotechnical ground improvement practices commonly used today and has a variety of potential applications. This research focuses primarily on its use as a soil stabilization technique using the bacteria Sporosarcina Pasteurii and a single injection point percolation method adapted from previous research in granular soils. This method, and most published data, show an inherent variability in both physical and engineering properties due to the distribution of precipitated calcite within the specimen. The focus of this research is on the quantification of the variability in shear strength parameters induced …


Improving Search Ranking Using A Composite Scoring Approach, Larry D. Snedden Jan 2017

Improving Search Ranking Using A Composite Scoring Approach, Larry D. Snedden

UNF Graduate Theses and Dissertations

In this thesis, the improvement to relevance in computerized search results is studied. Information search tools return ranked lists of documents ordered by the relevance of the documents to the user supplied search. Using a small number of words and phrases to represent complex ideas and concepts causes user search queries to be information sparse. This sparsity challenges search tools to locate relevant documents for users. A review of the challenges to information searches helps to identify the problems and offer suggestions in improving current information search tools. Using the suggestions put forth by the Strategic Workshop on Information Retrieval …


Consensus Based Distributed Control In Micro-Grid Clusters, Syed Ahmed Fuad Jan 2017

Consensus Based Distributed Control In Micro-Grid Clusters, Syed Ahmed Fuad

Dissertations, Master's Theses and Master's Reports

With the increasing trend of utilizing renewable energy generators such as photovoltaic (PV) cells and wind turbines, power systems are transforming from a centralized power grid structure to a cluster of smart micro-grids with more autonomous power sharing capabilities. Even though the decentralized control of power systems is a reliable and cost effective solution, due to the inherent heterogeneous nature of micro-grids, optimal and efficient power sharing among distributed generators (DG’s) is a major issue which calls for advanced control techniques for voltage stabilization of the entire micro-grid cluster. The proposed consensus based algorithm in this thesis is a solution …


A 3d Biomimetic Scaffold Using Electrospinning For Tissue Engineering Applications, Samerender Nagam Hanumantharao Jan 2017

A 3d Biomimetic Scaffold Using Electrospinning For Tissue Engineering Applications, Samerender Nagam Hanumantharao

Dissertations, Master's Theses and Master's Reports

Electrospinning holds great promise for designing functional 3D biomimetic scaffolds for tissue engineering applications. The technique allows for the reproducible fabrication of 3D scaffolds with control over the porosity and thickness. In this work, a novel method for the synthesis of a 3D electroactive scaffold using electrospinning from polycaprolactone (PCL), Polyvinylidene Fluoride (PVDF) and Polyaniline (PANI) is reported. Additional scaffolds involving different morphologies of PCL, PCL-PVDF and PCL-PANI-PVDF were also fabricated and evaluated. The scaffolds were characterized using electron microscopy to visualize the morphologies. Infrared spectroscopy was used to confirm the presence of polymers and their respective phases in the …


Minimizing Run Time Of Finite Element Analyses: Applications In Conformable Cng Tank Modeling, Paul M. Roehm Jan 2017

Minimizing Run Time Of Finite Element Analyses: Applications In Conformable Cng Tank Modeling, Paul M. Roehm

Dissertations, Master's Theses and Master's Reports

REL Inc. has proposed a CNG tank that deviates from typical cylindrical storage methods. The goal of REL working with Michigan Tech is to minimize mass and meet NGV2 safety standards for pressure and drop testing for this tank.

The model has undulated outer surfaces and Schwarz P-surface internal geometry. To accurately mesh this, a small element size is necessary; this creates a model with millions of elements. In explicit analyses, this requires a large amount of computational resources to run.

This report focuses on methods to reduce model run time without reducing accuracy. Methods covered include creating symmetric building …


Simulation Of Human Ankle Trajectory During Stance Phase Of Gait, Leslie Castelino Jan 2017

Simulation Of Human Ankle Trajectory During Stance Phase Of Gait, Leslie Castelino

Dissertations, Master's Theses and Master's Reports

A simulation was developed which mimics the human gait characteristics based on the input of an individual’s gait trajectory. This simulation also estimates the impedance of the human ankle based on the ground reaction forces measured by the force plate. This simulation will accept alterations of the following parameters: total body weight, weight of the shank, weight of the foot, trajectories of the shank and foot of the individual and orientation of the force plate, which would generate a new gait trajectory for the ankle during the stance phase of gait. The goal of this simulation was to validate the …


Simulation Study On Effect Of Gas Charging And Egr In A Dual-Fuel Engine, Satyavenkata Naga Sai Sharath Gorthy Jan 2017

Simulation Study On Effect Of Gas Charging And Egr In A Dual-Fuel Engine, Satyavenkata Naga Sai Sharath Gorthy

Dissertations, Master's Theses and Master's Reports

Natural gas combined with diesel as micro pilot has the capabilities of achieving lower NOx and soot emissions. Optimization of the combustion process in engines with natural gas and diesel micro-pilot is essential to achieve higher efficiencies and loads. Gas charging (intake air boosting) and EGR are two technologies which when implemented in the natural gas-diesel engines, provide the opportunity to achieve higher efficiencies and loads and low emissions. Simulation study is one of the approaches to investigate the extent and effects of gas charging and EGR on the performance of the engine. With the rapid improvements over the past …


The Visual And Performing Arts In The Technical Communication Classroom: Reinforcing The University's Internal Community Literacy Via Service-Learning, Richard L. Ward Jan 2017

The Visual And Performing Arts In The Technical Communication Classroom: Reinforcing The University's Internal Community Literacy Via Service-Learning, Richard L. Ward

Dissertations, Master's Theses and Master's Reports

This report details a class taught that was an exploration into the value of STEAM or science, technology, engineering, arts, and mathematics within the confines of Technical Communication as it applies to the business and industry of theatre. It was an experiment in service learning as it could be tied into the Arts via differing technai, as described by John Wild in “Plato’s Theory of Texnh a Phenomenological Interpretation,” demonstrating a necessity for Arts as they pertain to STEM-centric universities. This report discusses a section of Technical and Professional Communication taught at Michigan technological University that consisted of twenty-five students …


Techno-Economic And Life Cycle Assessments Of Biofuel Production From Woody Biomass Through Torrefaction-Fast Pyrolysis And Catalytic Upgrading, Olumide Winjobi Jan 2017

Techno-Economic And Life Cycle Assessments Of Biofuel Production From Woody Biomass Through Torrefaction-Fast Pyrolysis And Catalytic Upgrading, Olumide Winjobi

Dissertations, Master's Theses and Master's Reports

Biofuel production through fast pyrolysis of biomass is a promising conversion route in the production of biofuels compatible with existing technology. The bio-oil produced from fast pyrolysis is a versatile feedstock that can be used as a heating oil or upgraded to a transportation hydrocarbon biofuel. Comparative study of a one-step, fast pyrolysis only pathway and a two-step torrefaction-fast pyrolysis pathway was carried out to evaluate the effect of torrefcation on (i) the minimum selling price of biofuel and (ii) the potential life cycle GHG emissions of the biofuel production pathway.

To produce bio-oil which can serve as a substitute …


Performance Comparison Of Binarized Neural Network With Convolutional Neural Network, Lopamudra Baruah Jan 2017

Performance Comparison Of Binarized Neural Network With Convolutional Neural Network, Lopamudra Baruah

Dissertations, Master's Theses and Master's Reports

Deep learning is a trending topic widely studied by researchers due to increase in the abundance of data and getting meaningful results with them. Convolutional Neural Networks (CNN) is one of the most popular architectures used in deep learning. Binarized Neural Network (BNN) is also a neural network which consists of binary weights and activations. Neural Networks has large number of parameters and overfitting is a common problem to these networks. To overcome the overfitting problem, dropout is a solution. Randomly dropping some neurons along with its connections helps to prevent co-adaptations which finally help in reducing overfitting. Many researchers …


Simulation Of Diesel Particulate Filter Regeneration Using Lattice Boltzmann Method, Kshitiz Kumar Jain Jan 2017

Simulation Of Diesel Particulate Filter Regeneration Using Lattice Boltzmann Method, Kshitiz Kumar Jain

Dissertations, Master's Theses and Master's Reports

Lattice Boltzmann Method is a novel approach, which has shown promise in solving a wide variety of fluid flow problems including single and multi-phase flows in complex geometries. Volume elements of the fluid domain are considered to be composed of particles and these particles fall under a velocity distribution function at each grid point. Particles collide with each other under the influence of external forces and the rules of collision are defined so as to be compatible with the Navier-Stokes Equation. In the current work, LBM has been applied to Diesel Particulate filters which is a device used for reducing …


Synthesis And Characterization Of Cross-Linked Polyimide Film Using Tolylene Diisocyanate, Sirichai Reeyakad Jan 2017

Synthesis And Characterization Of Cross-Linked Polyimide Film Using Tolylene Diisocyanate, Sirichai Reeyakad

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cross-linked polyimide films were synthesized by the reaction between diisocyanate groups and hydroxyl functional groups in polyimide structure, which was confirmed by IR. During the thermal treatment of the cross-linked polyimide, the thermal labile component (CO₂) in the urethane segments was decomposed which might generate pores in the film. The presence of the pores was confirmed from the dielectric constant of the film. The dielectric constant of the films decreased with the increase of TDI loading. By comparing the properties of the films, the PI50-C1.0 exhibited optimum mechanical and good dielectric properties. The cross-linked structure was also confirmed by DMA. …


ผลของการเติมเถ้าแกลบต่อการเกิดชั้นฟิล์มในกระบวนการอะลูมิไนซิงแบบผงบนนิกเกิลบริสุทธิ์, บุญฤทธิ์ เฮงประยูร Jan 2017

ผลของการเติมเถ้าแกลบต่อการเกิดชั้นฟิล์มในกระบวนการอะลูมิไนซิงแบบผงบนนิกเกิลบริสุทธิ์, บุญฤทธิ์ เฮงประยูร

Chulalongkorn University Theses and Dissertations (Chula ETD)

การปรับปรุงกระบวนการอะลูมิไนซิงแบบผงทำได้โดยการเจือธาตุซิลิกอนเพื่อเพิ่มความเสถียรของชั้นออกไซด์ที่เกิดขึ้นในการใช้งานที่อุณหภูมิสูง ซึ่งเถ้าแกลบมีส่วนประกอบของซิลิกาอยู่มากกว่า 90 เปอร์เซ็นต์โดยน้ำหนัก ในงานวิจัยนี้จะหาความเป็นไปได้ในการใช้เถ้าแกลบแทนซิลิกาจากอุตสาหกรรม (ควอทซ์) เพื่อเจือซิลิกอนลงในกระบวนการอะลูมิไนซิงแบบผง โดยวิเคราะห์ถึงความแตกต่างของโครงสร้างผลึก สารเจือในเถ้าแกลบ ขนาดอนุภาค ลักษณะพิ้นผิวและพื้นที่ผิวจำเพาะระหว่างผงควอทซ์และผงเถ้าแกลบที่จะส่งผลต่อโครงสร้างจุลภาค โครงสร้างของสารประกอบของชั้นแพร่และปริมาณซิลิกอนที่พบในชั้นแพร่ในผิวชิ้นงานที่ใช้สารตั้งต้นเป็นควอทซ์และเถ้าแกลบ ซึ่งปริมาณสารเจือที่เติมคือ 9, 13.5, 18 เปอร์เซ็นต์โดยน้ำหนัก เผาที่อุณหภูมิ 800 และ 1000๐C เป็นเวลา 4 ชั่วโมง และทดสอบความต้านทานการเกิดออกซิเดชันที่อุณหภูมิ 1000๐C เป็นเวลา 100 ชั่วโมง ชิ้นงานที่นำมาทดสอบคือ นิกเกิลบริสุทธิ์, ชิ้นงานที่ทำอะลูมิไนซิงที่ 900๐C เป็นเวลา 4 ชั่วโมง, ชิ้นงานที่เติมควอทซ์ 13.5 เปอร์เซ็นต์โดยน้ำหนัก ทำอะลูมิไนซิงที่ 1000๐C เป็นเวลา 4 ชั่วโมงและชิ้นงานที่เติมเถ้าแกลบ 13.5 เปอร์เซ็นต์โดยน้ำหนัก ทำอะลูมิไนซิงที่ 1000๐C เป็นเวลา 4 ชั่วโมง นำชิ้นงานมาวิเคราะห์ลักษณะพื้นผิวและโครงสร้างของสารประกอบออกไซด์ที่เกิดขึ้นที่ผิว พบว่าชิ้นงานที่เติมเถ้าแกลบจะมีปริมาณซิลิกอนที่พบในชั้นแพร่มากกว่าและมีความสามารถในการต้านทานการเกิดออกซิเดชันที่อุณหภูมิสูงดีกว่าชิ้นงานที่เติมควอทซ์


Long-Period Fiber Grating Corrosion Sensors For Life-Cycle Monitoring And Assessment Of Reinforced Concrete Structures, Yizheng Chen Jan 2017

Long-Period Fiber Grating Corrosion Sensors For Life-Cycle Monitoring And Assessment Of Reinforced Concrete Structures, Yizheng Chen

Doctoral Dissertations

"This study aims to: (1) explore, develop, calibrate and validate Fe-C coated, long period fiber grating (LPFG) sensors for short-term mass loss measurement of the Fe-C coating; (2) develop, calibrate, and validate steel tube-encapsulated, fiber optic probes and LPFG sensors for long-term mass loss detection of the steel tube; (3) correlate the corrosion process of packaging metal materials with that of steel bars in direct contact with the packaged probe or sensor except for a thin insulation tape; and (4) apply both types of corrosion sensors into reinforced concrete (RC) structures for reinforcing bar corrosion monitoring and structural condition assessment. …


Repair Of Metallic Components Using Hybrid Manufacturing, Renwei Liu Jan 2017

Repair Of Metallic Components Using Hybrid Manufacturing, Renwei Liu

Doctoral Dissertations

"Many high-performance metal parts users extend the service of these damaged parts by employing repair technology. Hybrid manufacturing, which includes additive manufacturing (AM) and subtractive manufacturing, provides greater build capability, better accuracy, and surface finish for component repair. However, most repair processes still rely on manual operations, which are not satisfactory in terms of time, cost, reliability, and accuracy. This dissertation aims to improve the application of hybrid manufacturing for repairing metallic components by addressing the following three research topics. The first research topic is to investigate and develop an efficient best-fit and shape adaption algorithm for automating 3D models' …


Discrete Ordinates Ct Organ Dose Simulator (Doctors), Edward T. Norris Jan 2017

Discrete Ordinates Ct Organ Dose Simulator (Doctors), Edward T. Norris

Doctoral Dissertations

"Computed tomography (CT) has become pervasive in medical diagnostics as improved imaging techniques and processing algorithms provide higher quality information to doctors. However, the exponentially increasing usage of CT has raised concerns regarding long term low-dose radiological risks.

Currently, the dose to patients is computed using Monte Carlo methods and experimental tests. In other areas of radiation transport, deterministic codes have been shown to be much faster than Monte Carlo codes.

Currently, no deterministic methodology exists to automatically generate a spatially distributed dose profile from a CT voxel phantom. This work proposes a new code, Discrete Ordinate CT Organ Dose …


Volumetric Error Compensation For 5-Axis Machine Tools, Jennifer Ruth Creamer Jan 2017

Volumetric Error Compensation For 5-Axis Machine Tools, Jennifer Ruth Creamer

Doctoral Dissertations

"This work presents a geometric error compensation method for large 5-axis machine tools. The compensation method presented here uses tool tip measurements recorded throughout the axis space to construct a position-dependent geometric error model that can easily be used for error compensation. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. First two model types are compared for generating table-based error compensation and experimental results are presented. Table-based compensation is then extended to machine tool controller types with restrictions on the number or combination of compensation tables using an …