Engineering Commons^™

Real-Time Monitoring Of Sand And Dust Storm Winds Using Wireless Sensor Technology, Hana Mohammed Mujlid

Theses and Dissertations

This dissertation proposes an empirical model for prediction of the radio path loss in Wireless Sensor Networks (WSNs). The model applies to WSNs that are deployed in environments with dust and sand storms. It is developed as a result of statistical analysis of the measured data collected during dust and sand storms. The measured data were obtained at 2.4GHz and for different levels of the storm severity. For the purpose of data collection a custom measurement system based on Xbee air interface was developed. The proposed model shows a very good agreement with the measured data. It is also demonstrated …

Quantification Of Frictional Drag Due To Biofouling On In-Service Ships, John Travis Hunsucker

Theses and Dissertations

The purpose of this research was to improve the quantification of frictional drag due to biofouling on in-service ships by advancing the knowledge and methodology used to study the interactions between fouling communities and the surrounding environment. This research examined the influence of hydrodynamic stress on the development and frictional drag of fouling communities that developed on a fouling release coating; investigated the reliability of using ship performance monitoring to detect changes in the hull and propeller condition; and evaluated the feasibility of developing a field deployable instrument capable of measuring the local frictional resistance on a ship hull in …

A Systems Engineering Approach For Plant Layout Management & Optimization, Abdulelah Saeed Algarni

Theses and Dissertations

The basis of this paper was to investigate the system engineering applications on petro-chemical facilities layout designs. This work aims to facilitate and introduce the application of Facility Layout Problems to industrial case studies based on system engineering methodologies and performance measurements. Additionally, an effort was made to present a state-of-the-art literature review of industrial layout problems that exhibits scarcity of system engineering role in the design and implementations of industrial Facility Layout Problems. Facility Layout is one of the demanding large-scale optimization problems. Upon the completion of this report, we found a great sense of vitality of system engineering …

Robust Speaker Recognition In The Presence Of Speech Coding Distortion, Robert Walter Mudrosky

Theses and Dissertations

For wireless remote access security, forensics, border control and surveillance applications, there is an emerging need for biometric speaker recognition systems to be robust to speech coding distortion. This thesis examines the robustness issue for three coders, namely, the ITU-T 6.3 kilobits per second (kbps) G.723.1, the ITU-T 8 kbps G.729 and the 12.2 kbps 3GPP GSM-AMR coder. Both speaker identification (SI) and speaker verification (SV) systems are considered and use a Gaussian mixture model (GMM) classifier. The systems are trained on clean speech and tested on the decoded speech. To mitigate the performance loss due to mismatched training and …

Sensitivity Studies On The Shear Lag Parameter Β Using Analytical And Numerical Techniques, George Thomas Avery

Theses and Dissertations

The strength of fiber-reinforced composites is dependent on the strength of the fiber-matrix interface bond. Thermal, chemical, and other means have been used to modify the surface of fibers, resulting in increased fiber-matrix interface bond strength. However, researchers are still dependent on empirical methods to relate surface modifications to composite performance. Additional efforts are required to develop physics-based models for micro-mechanical effects on interfacial bond strength that will be needed for the improved design and processing of fiber reinforced composites. It is anticipated that experimental, numerical, and analytical efforts will be needed to contribute toward this endeavor.

A numerical approach …

Design Maps For Fracture Resistant Functionally Graded Materials, Muhammad Ridwan Murshed

Theses and Dissertations

The objective of this research is to generate design maps to identify functionally graded microstructures with enhanced fracture toughness. Several Functionally Graded Materials (FGMs) with an edge crack and membrane loading are considered and the resulting J-integral values are computed numerically using Finite Element Analysis. In order to capture the resulting stress fields accurately, Barsoum elements are used in the vicinity of the crack tip and the simulations are carried out for several crack lengths (a) and material contrasts (κ). The averages of the J-integral values are used to determine the normalized Stress Intensity Factors which are then benchmarked with …

Fundamental Principles Of Tremor Propagation In The Upper Limb, Andrew Doran Davidson

Theses and Dissertations

Although tremor is the most common movement disorder, there exist few effective tremor-suppressing devices, in part because the characteristics of tremor throughout the upper limb are unknown. To clarify, optimally suppressing tremor requires a knowledge of the mechanical origin, propagation, and distribution of tremor throughout the upper limb. Here we present the first systematic investigation of how tremor propagates between the shoulder, elbow, forearm, and wrist. We simulated tremor propagation using a linear, time-invariant, lumped-parameter musculoskeletal model relating joint torques and the resulting joint displacements. The model focused on the seven main degrees of freedom (DOF) from the shoulder to …

Packing Sheet Materials Into Cylinders And Prisms Using Origami-Based Approaches, Jared Thomas Bruton

Theses and Dissertations

Packing sheet materials into cylinders and prisms using Origami-based approaches (Soft Origami or traditional Origami) is of interest in fields where sheet materials need folded into cylinders or prisms. Fully-dense packing has application in fields where a sheet material is to be folded with minimal gaps into a cylinder or prism. Partially-dense packing is applicable to fields where gaps are required between packed surfaces or where hollow volumes are to be filled, such as in fluid filter design. Soft Origami is explored as a method for folding soft-sheet materials into fully-dense cylinders. Two fold patterns, the "flasher'' and the "inverted-cone …

A Visual Return-To-Home System For Gps-Denied Flight, Benjamin Paul Lewis

Theses and Dissertations

Unmanned aerial vehicle technology is rapidly maturing. In recent years, the sight of hobbyist aircraft has become more common. Corporations and governments are also interested in using drone aircraft for applications such as package delivery, surveillance and communications. These autonomous UAV technologies demand robust systems that perform under any circumstances. Many UAV applications rely on GPS to obtain information about their location and velocity. However, the GPS system has known vulnerabilities, including environmental signal degradation, terrestrial or solar weather, or malicious attacks such as GPS spoofing. These conditions occur with enough frequency to cause concern. Without a GPS signal, the …

Value Based Methodology To Evaluate Sensors For Bridge Structural Health Monitoring Systems, Jefferson Santos De Oliveira

Theses and Dissertations

Structural health monitoring (SHM) systems have become important tools in the transportation industry to help monitor the behavior and health of civil structures. Today, there is a real concern about the health of bridges because these structures are aging, and various failure events have contributed to increase that concern. Consequently, the topic of improving the effectiveness and appropriate use of SHM systems have become the focus of various government agencies and researchers, both in industry and academia. In this context, this thesis work was developed to understand the general components of bridge SHM systems, and present a methodology to help …

Repair Severed Nerve Connections Through A Multi-Branch Microchannel Scaffold To Control The Direction Of The Regenerated Nerve, Luis Enrique Castanuela Ramon

Theses and Dissertations

Damage to the peripheral nervous system may result in functional abnormalities due to disrupted nerve connections. Existing methods of repairing severed nerve connections in the peripheral nervous system have limitations and disadvantages such as a limited availability of donor nerves and a lack of control of the direction of nerve regeneration within nerve conduits. A handcrafted multi-branch microchannel scaffold improves upon the current methods of nerve repair by incorporating microchannels, which guide and accommodate the nerve regeneration to distal ends, allowing for the treatment of nerve injuries involving multiple branches with fewer surgeries. This scaffold is also made more accessible …

Biocompatible Microchannel Scaffold With Microwires For Recording Regenerative Peripheral Nerve Neural Spikes, Manisankar Chennamsetti

Theses and Dissertations

A new process for the fabrication of a microchannel scaffold with microwires for peripheral nerve applications is presented. This microchannel scaffold implemented between the ends of nerves, the axons of which regenerate through microchannel in scaffold and fixed microelectrodes. This device is entirely handcrafted using commercially available materials such as microwires, PDMS film, liquid PDMS, dental cement, and epoxy glue. This device was implemented in the a Lewis rat sciatic nerve to better analyze the electrical signals of regenerated axons. 64-electrode microchannel scaffolds were developed for both peripheral nerve interfacing and peripheral nerve regeneration. The microwires were used for recording …

Comparing Efficacy Of Different Dynamic Models For Control Of Underdamped, Antagonistic, Pneumatically Actuated Soft Robots, Morgan Thomas Gillespie

Theses and Dissertations

Research in soft robot hardware has led to the development of platforms that allow for safer performance when working in uncertain or dynamic environments. The potential of these platforms is limited by the lack of proper dynamic models to describe or controllers to operate them. A common difficulty associated with these soft robots is a representation for torque, the common electromechanical relation seen in motors does not apply. In this thesis, several different torque models are presented and used to construct linear state-space models. The control limitations on soft robots are induced by natural compliance inherent to the hardware. This …

Position And Stiffness Control Of Inflatable Robotic Links Using Rotary Pneumatic Actuation, Charles Mansel Best

Theses and Dissertations

Inflatable robots with pneumatic actuation are naturally lightweight and compliant. Both of these characteristics make a robot of this type better suited for human environments where unintentional impacts will occur. The dynamics of an inflatable robot are complex and dynamic models that explicitly allow variable stiffness control have not been well developed. In this thesis, a dynamic model was developed for an antagonistic, pneumatically actuated joint with inflatable links.The antagonistic nature of the joint allows for the control of two states, primarily joint position and stiffness. First a model was developed to describe the position states. The model was used …

3d Object Recognition For A Portable Robotic Navigation Aid, Xiangfei Qian

Theses and Dissertations

The objective of this dissertation is to develop a 3D object recognition method for a portable robotic navigation aid, called “Smart Cane” (SC), for the visually impaired. The SC is a computer-vision-enhanced white cane that uses a single 3D time-of-flight camera for navigation in an indoor environment. To achieve the navigation function, the SC should be able to perform SLAM (Simultaneous Localization And Mapping) and object recognition. In this dissertation, we focus on object recognition. Firstly, a method, named Normal-Coherence-Check RANSAC (RANdom Sample Consensus), is proposed to perform robust and fast plane extraction. Secondly, a 3D object recognition method based …

Thermal Modeling And Nanoindentation Of Shape Memory Alloy Thin Films, Mehmet Mete Ozturk

Theses and Dissertations

Metal alloys which go through a hysteric transformation due to external stimuli such as thermal and/or mechanical fields are called shape memory alloys (SMA). Thin films of SMAs have many remarkable features and have been used in the fabrication of microactuators. One potential application is a SMA thin film based information storage device. In all these applications, the existence of the strong thermomechanical coupling inherent in the phase transformation is seen. Due to coupling, knowledge of not only the mechanical field but also the thermal field is essential. The objective of this work is to study the thermal behavior of …

Alkali Silica Reaction In Concrete Made From Arkansas Region, Adithya Reddy Mallu

Theses and Dissertations

Alkali-Silica Reaction is an unwanted reaction which occurs over time between cement paste and silica. This in turn alters the expansion of the aggregate and often in an unpredictable way, which will result in loss of strength of concrete and complete failure. This research studies the effects of using locally available coarse and fine aggregates available in Arkansas. This research will provide the necessary information in selecting the type of aggregate that is to be used in constructions and a viable comparison between different aggregates available in Arkansas have been made. Different materials used for preparation of concrete samples have …

Modeling Atypical Building Use With Commercially Available Building Simulation Software, Sarah E. Schanck

Theses and Dissertations

National Guard armories are audited to provide recommendations for future energy reduction measures. The annual energy consumption of a New Jersey National Guard Armories cannot be modeled directly with commercially available building simulation software, due to discrepancies between the modeling capabilities of the software and the reality of the armory. A building simulation software, eQUEST, was chosen for use in this project. Discrepancies between eQUEST inputs and reality were identified and correction factors developed to minimize the effect of each discrepancy on predicted energy consumption, with the end goal of accuracy between predicted and actual energy consumption. In addition, an …

The Effects Of Antenna Coupling In A Mimo Radar System, Benjamin T. Arnold

Theses and Dissertations

A mathematical model for a multiple-input multiple-output radar system is presented. The model is used to track signals through the system in order to identify the impact of antenna array mutual coupling on radar system performance. Simulations using the model provide quantitative assessment of the performance degradation as a function of antenna coupling strength. Specifically, the results show that coupling can cause a target to appear at an angle notably different than its actual angle and can cause an increase in the side lobe level. A compensation technique is presented that completely removes these effects for practical levels of coupling. …

Numerical Modeling Of Soy Biodiesel To Maximize Engine Power And Efficiency While Minimizing Pollutant Emissions, Ehsan Tootoonchi

Theses and Dissertations

Biodiesel is a renewable fuel that can help to reduce dependence on foreign petroleum and to help control the negative environmental effects of combustion engines. This work develops a numerical model for soy biodiesel combustion in diesel engine applications. A comprehensive breakup model for diesel and biodiesel combustion calculations using the KIVA- 3V is presented. The primary breakup model calculates the outcome of the initial breakup stage using flow conditions, nozzle geometry, and liquid fuel characteristics, and assigns the Sauter Mean Radius (SMR) values to injecting droplets. The Kelvin-Helmholtz/Rayleigh-Taylor(KH-RT) model acts as the secondary model to break up injected particles. …

The Controlled Human Gyroscope, Randy Claude Arjunsingh

Theses and Dissertations

The objective of this thesis was to design an adaptive rotational motion simulator capable of replicating the attitudes of spacecrafts and aircrafts, while avoiding gimbal lock. Flight motion simulators are currently used for flight training and research, but there are many limitations to these existing systems. This thesis presents a low-cost design for a rotational motion platform titled, ‘The Controlled Human Gyroscope’. It uses a 4-axis system instead of the conventional 3-axis system to avoid gimbal lock and prevent the unnecessary motion of the user. The Human Gyroscope features unlimited rotation about the roll, pitch and yaw axes regardless of …

Simplified Performance-Based Analysis For Seismic Slope Displacements, Marlem Lucia Astorga Mejia

Theses and Dissertations

Millions of lives have been lost over the years as a result of the effects of earthquakes. One of these devastating effects is slope failure, more commonly known as landslide. Over the years, seismologists and engineers have teamed up to better record data during an earthquake. As technology has advanced, the data obtained have become more refined, allowing engineers to use the data in their efforts to estimate earthquakes where they have not yet occurred. Several methods have been proposed over time to utilize the earthquake data and estimate slope displacements. A pioneer in the development of methods to estimate …

Enabling Studies To Optimize Biomaterials For The Treatment Of Myocardial Infarction, Eva Adriana Romito

Theses and Dissertations

The canonical mechanism of wound healing is disrupted following a myocardial infarction (MI), manifesting as an unregulated response that negatively impacts left ventricular (LV) function. This mechanism, termed post-MI remodeling, culminates in an outcome that favors progression to a systolic heart failure state and death for the patient. Therapeutic approaches following the occurrence of a MI are designed to modulate the natural remodeling process and mitigate the loss of cardiac function. The mechanics and structure of the healing infarct have been the focus of numerous pre-clinical and clinical investigations, leading to the impending clinical introduction of material injections as a …

Study Of Friction Extrusion And Consolidation, Xiao Li

Theses and Dissertations

Friction extrusion and consolidation was invented by The Welding Institute (Cambridge, UK) in the early 1990’s. It is related to simple extrusion processes with the primary difference being that the extrusion die rotates about the extrusion axis and the die is required to impart substantial deformation to the initially, finely divided charge (like metal waste or chips) in order to consolidate it prior to extrusion. It can produce high quality wire and fully consolidated bulk material from low-cost precursors like metal chips or powders. The advantages lie in that it is a direct method to recycle metal chips or scraps …

Ultra-High Temperature Full Field Deformation Measurements Of Materials Subjected To Thermo-Mechanical Loading: A Dic Based Study, Guillemo A. Valeri Paoli

Theses and Dissertations

Determining the mechanical response of materials at elevated temperatures is a subject of great interest in metal forming, aerospace and aero-engine industries. For example, measurement of the deformation response under tensile loading at high temperatures is crucial for establishing thermomechanical and thermo-physical properties of materials, consequently, determining the reliability of a component or structure exposed to elevated temperatures. In order to predict the behavior of materials at ultra-high temperatures, a novel experimental approach based on Digital Image Correlation (DIC) is proposed and successfully applied to different materials at temperatures ranging from room temperature to 1100˚C. In these studies, a portable …

Engineered Earthen Masonry Structures For Extreme Wind Loads, Mabel Cristina Cuellar-Azcarate

Theses and Dissertations

Stabilized earthen masonry (SEM), which is built with compressed stabilized earthen blocks (CSEB) and mortar, is emerging as a construction system for affordable, sustainable and high-quality dwellings. Compelling features of earthen masonry are local availability of suitable soils, thermal insulation properties, humidity control within healthy ranges, and relatively low carbon footprint. SEM is also appealing for the construction of affordable houses in rural areas and farmlands, where underrepresented and underprivileged groups often live. In fact, the lack of affordable housing is an issue across the United States where low-income families are most affected, often committing more than half of their …

Comparative Analysis Of Current Control Methods For Modular Multilevel Converters, Jordan D. Rogers

Theses and Dissertations

Modular Multilevel Converters (MMCs) are power electronic converters comprised of a series connection of sub-modules. Their modular structure allows for the possibility to design high-voltage converters that are suitable for utility applications due to the modular fail-safe structure with reduced switching frequency requirements. Some areas of interesting research specific to the MMC topology include modulation techniques, control methods, capacitor voltage balancing strategies, and circulating current suppression control. This thesis presents the development of a predictive current control for MMCs that has the benefit of inherently reduced circulating currents within the converter’s phase units. Two other typical MMC current control strategies …

Development Of Pressure Swing Adsorption (Psa) Processor Co2 Capture From Flue Gas, Md. Atikur Rahman

Theses and Dissertations

Reducing the anthropogenic CO2 emissions and lowering the concentration of greenhouse gases in the atmosphere has become one of the most important environmental issues of recent times. To this end, the development of a cost effective pressure swing adsorption (PSA) process, utilizing commercially available 13X zeolite as the adsorbent, is underway to remove and concentrate CO2 in the flue gas of a coal-fired power plant. This systematic development effort has been carried out so far at the bench scale. It has included the following studies that defined and validated this PSA process both experimentally and via a PSA process model. …

Polyphenols As Natural, Dual-Action Therapeutics For Alzheimer's Disease, Kayla M. Pate

Theses and Dissertations

Alzheimer’s disease (AD), the most common form of dementia, is characterized by extracellular plaques in the brain created when monomeric amyloid-β (Aβ) protein aggregates into fibrillar structures. Soluble Aβ aggregates, including oligomers, that form along the reaction pathway are believed to be the primary pathogenic species and have been shown to increase the production of reactive oxygen species (ROS). This upregulation of ROS is one suggested contributing factor of Aβ aggregate cytotoxicity and has proven capable of mediating cell signaling associated with Aβ aggregate-induced cellular responses.

Polyphenols have been suggested as a complimentary AD therapeutic based on epidemiological evidence that …

Numerical Modeling Of Heat Transfer And Material Flow During Friction Extrusion Process, Hongsheng Zhang

Theses and Dissertations

Friction extrusion process is a novel manufacturing process that converts low-cost metal precursors (e.g. powders and machining chips) into high-value wires with potential applications in 3D printing of metallic products. However, there is little existing scientific literature involving friction extrusion process until recently. The present work is to study the heat transfer and material flow phenomena during the friction extrusion process on aluminum alloy 6061 through numerical models validated by experimental measurements.

The first part is a study of a simplified process in which flow of a transparent Newtonian fluid in a cylindrical chamber caused by frictional contact with a …