Engineering Commons^™

Engineering Applications Of Organic Surfactant Modified Bentonite In Sorptive Soil Barriers., Sadra Javadi

Electronic Theses and Dissertations

Earthen barriers such as CCLs and GCLs have been employed in geotechnical practices to provide a low permeability hydraulic barrier since long time ago. These types of barriers exhibited satisfactory performance for many applications such as landfills. The performance of low permeability barriers is based on the swelling potential of their component, which is mostly Na-bentonite, in contact with polar fluids such as water. However, the acceptable range of conductivity cannot be achieved by traditional earthen barriers when they are permeated by non-polar fluids such as gasoline. This phenomenon occurs due to the incompatibility of earthen barrier constituent with non-polar …

Dynamic Adversarial Mining - Effectively Applying Machine Learning In Adversarial Non-Stationary Environments., Tegjyot Singh Sethi

Electronic Theses and Dissertations

While understanding of machine learning and data mining is still in its budding stages, the engineering applications of the same has found immense acceptance and success. Cybersecurity applications such as intrusion detection systems, spam filtering, and CAPTCHA authentication, have all begun adopting machine learning as a viable technique to deal with large scale adversarial activity. However, the naive usage of machine learning in an adversarial setting is prone to reverse engineering and evasion attacks, as most of these techniques were designed primarily for a static setting. The security domain is a dynamic landscape, with an ongoing never ending arms race …

An Interactive Interface For Nursing Robots., Ankita Sahu

Electronic Theses and Dissertations

Physical Human-Robot Interaction (pHRI) is inevitable for a human user while working with assistive robots. There are various aspects of pHRI, such as choosing the interface, type of control schemes implemented and the modes of interaction. The research work presented in this thesis concentrates on a health-care assistive robot called Adaptive Robot Nursing Assistant (ARNA). An assistive robot in a health-care environment has to be able to perform routine tasks and be aware of the surrounding environment at the same time. In order to operate the robot, a teleoperation based interaction would be tedious for some patients as it would …

Frequency Sensitive Mechanism In Low-Intensity Ultrasound Enhanced Bioeffects, April D. Miller, Abdoulkadri Chama, Tobias M. Louw, Anuradha Subramanian, Hendrik J. Viljoen

Department of Chemical and Biomolecular Engineering: Faculty Publications

This study presents two novel theoretical models to elucidate frequency sensitive nuclear mechanisms in low-intensity ultrasound enhanced bioeffects. In contrast to the typical 1.5 MHz pulsed ultrasound regime, our group previously experimentally confirmed that ultrasound stimulation of anchored chondrocytes at resonant frequency maximized gene expression of load inducible genes which are regulatory markers for cellular response to external stimuli. However, ERK phosphorylation displayed no frequency dependency, suggesting that the biochemical mechanisms involved in enhanced gene expression is downstream of ERK phosphorylation. To elucidate such underlying mechanisms, this study presents a theoretical model of an anchored cell, representing an in vitro …

A Gps Signal Generator Using A Roach Fpga Board, Kurt L. Pedrosa

Doctoral Dissertations and Master's Theses

A Global Positioning System (GPS) signal simulator is a valuable testing tool. It allows for testing of GPS receivers, systems, and anti-spoofing algorithms. With the increased popularity of software defined radios (SDRs) merging GPS signal simulators and SDRs is a natural choice. A detailed review of the construction of a GPS signal generator using the ROACH processing board is presented herein. The ROACH, developed by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) team, is a processing board that can be configure to function as a SDR. In this research, the ROACH was transformed to function as a …

A Low Temperature Co-Fired Ceramic (Ltcc) Interposer Based Three-Dimensional Stacked Wire Bondless Power Module, Atanu Dutta

Graduate Theses and Dissertations

The objective of this dissertation research is to develop a low temperature co-fired ceramic (LTCC) interposer-based module-level 3-D wire bondless stacked power module. As part of the dissertation work, the 3-D wire bondless stack is designed, simulated, fabricated and characterized. The 3-D wire bondless stack is realized with two stand-alone power modules in a half-bridge configuration. Each stand-alone power module consists of two 1200 V 25 A silicon insulated-gate bipolar transistor (IGBT) devices in parallel and two 1200 V 20 A Schottky barrier diodes (SBD) in an antiparallel configuration. A novel interconnection scheme with conductive clamps and a spring loaded …

Experiment-Based Quantitative Modeling For The Antibacterial Activity Of Silver Nanoparticles, Mohammad Aminul Haque

Graduate Theses and Dissertations

Silver (Ag) has been well known for its antimicrobial activity for a long time. Recent research showed the potential of Ag nanoparticles as emerging antimicrobial agents. However, little quantitative analysis has been performed so far to decipher the mechanism of interaction between nanoparticles and bacteria. Here, a detailed analysis based on kinetic growth assay and colony forming unit assay has been carried out to study the antimicrobial effect of Ag nanoparticles against Escherichia coli (E. coli) bacteria. It was observed that the presence of Ag nanoparticles increased the lag time of bacterial growth while not affecting the maximum growth rate …

The Effect Of Magnification Loupes On Dental Hygienists' Posture While Exploring, Emily Ludwig, Gayle B. Mccombs, Susan L. Tolle, Daniel M. Russell

Dental Hygiene Faculty Publications

Purpose: The purpose of this study was to determine the effects of dental magnification loupes on posture during instrumentation.

Methods: A convenience sample of 27 right-handed dental hygienists, with no prior history of injuries or disabilities of the head, neck, or trunk region, enrolled in the study. Baseline posture calibration was taken and tri-axial accelerometers were placed on four locations of the head and trunk (occipital region of head; cervical vertebrae C5; thoracic vertebrae T5; lumbar vertebrae L1) to measure acceleration and the orientation of the body to gravity. Participants were randomly assigned to wear self-supplied magnification loupes during either …

The Macro-Modelling Of Steel Fiber Reinforced Concrete/Mortar Flexural Tensile Behavior And Mix Optimization For Flexural Strength., Li Liu

Electronic Theses and Dissertations

With the continuous advances in materials’ technology, the performance of the commonly used concrete building material has continued to improve. Compressive strengths exceeding 75 MPa are now being used in applications throughout the world. However, the concrete becomes less ductile and more susceptible to sudden failures with increases in its compressive strength. Although the behavior of concrete is generally governed by its compressive strength, its tensile strength, although much lower, is also important. This tensile strength impacts appearance, the serviceability and durability of concrete elements. In addition, minimum levels of tensile strength are required for many concrete applications including, earthquake …

Observation And Estimation Study For Sensorless Control Of Linear Vapor Compressors., Joseph Latham

Electronic Theses and Dissertations

Linear vapor compressors have become widely investigated for refrigeration applications due to their high efficiency in comparison to the more common rotary type compressors. However, the nature of the linear compressor adds complexity to the control of these machines. The unconstrained motion of the piston in a linear compressor allows for continuous modulation of the compressor output, but requires knowledge of the mechanical dynamics to effectively control the compressor and prevent collision of the piston with the cylinder head. This control is made more difficult by the highly nonlinear nature of the force of gas compression acting against the piston. …

Applications Of Polarized Metallic Nanostructures., Jasmin Beharic

Electronic Theses and Dissertations

Gold nanostructures exhibit technologically useful properties when they are polarized in an electric field. In two projects we explore instances where the polarized metal can be used in real world applications. The first project involves gold nanoparticles (GNP) for use in light actuated microelectromechanical systems (MEMS) applications. Although the GNPs were originally designed for volumetric heating in biomedical applications, we treat them as a thin film coating, opening the door for these particles to be used in MEMS applications. This work characterizes the thermal properties of gold nanoparticles on surfaces for spatially-targeted thermal actuation in MEMS systems. The second project …

A Data Science Pipeline For Educational Data : A Case Study Using Learning Catalytics In The Active Learning Classroom., Asuman Cagla Acun Sener

Electronic Theses and Dissertations

This thesis presents an applied data science methodology on a set of University of Louisville, Speed School of Engineering student data. We used data mining and classic statistical techniques to help educational researchers quickly see the data trends and peculiarities. Our data includes scores and information about two Engineering Fundamental Class. The format of these classes is called an inverted classroom model or flipped class. The purpose of this study is to analyze the data in order to uncover potentially hidden information, tell interesting stories about the data, examine student learning behavior and learning performance in an active learning environment, …

Fabrication And Characterization Of A Mcro/Nanofluidic Platform For Electroporation., Hanwen Yuan

Electronic Theses and Dissertations

For traditional electroporation devices, there are a number of problems associated with these devices such as insufficient understanding of its theoretical mechanism, low cell viability, inadequate electroporation efficiency, excess voltage applied to generate required electric field due to the large size of these devices and sample contamination. Although newly developed microfluidic electroporation devices have solved most of the above existing problems in traditional bulk electroporation devices, they appear to lack the ability to control the precise dose of biomolecules or genes transfecting into cells and, from a manufacturing perspective, the fabrication methods do not enable repeatable production of such devices …

Magnetic Field-Induced Intramolecular Cyclization As A Trigger For Nanoparticle-Based Delivery Systems., Sara Katherine Biladeau

Electronic Theses and Dissertations

Magnetic nanoparticles (MNPs) are used in a variety of applications, including as agents for magnetic resonance imaging, generation of local hyperthermia, and as platforms for drug delivery. Iron-based MNPs are often coated with a shell, such as silica or gold, to increase biocompatibility for drug delivery applications. Many MNPs used for cancer therapy rely on either an internal trigger, such as a difference in pH, or an external trigger, such as light or an alternating magnetic field (AMF), to cause release of a payload, typically a chemotherapeutic drug. Internal triggers are appealing because drug release can be targeted to a …

A Smart Highway Work Zone Merge System Enabled By Connected Vehicles., Abdulmaged Algomaiah

Electronic Theses and Dissertations

Typical traffic control and operations at work zones usually are not very effective in mitigating the work zone bottleneck. A major reason is that the common early merge behaviors limits utilizing the available capacity in the closed lane, especially under moderate to high traffic demands. Recently, using late merge strategy is encouraged to prevent early merge behavior and fully utilize the closed lane and therefore increase capacity of work zone. The development of late merge strategy was not enough to substantially improve the situation due to the lack of compliance and communication among drivers. This thesis suggests and investigates a …

Cationic Surfactant Modification And Its Impact On The Engineering Behaviors Of Montmorillonite., Mohammad Ghavami

Electronic Theses and Dissertations

This study focuses on the microstructure of organoclays after organic surfactant modifications and the potential use in geoenvironmental engineering applications including waste containment in earthen barrier, rheological control agents for drilling fluid and soil stabilization. Organoclays, or clays modified by organic matters, are often synthesized by exchanging the naturally occurring interlayer inorganic cations (e.g., Na+, Ca²⁺) of the clay with organic cationic surfactants. In this research, montmorillonites intercalated with two quaternary ammonium surfactants, hexadecyltrimethylammonium (HDTMA+) and bis (hydrogenated tallow alkyl) dimethyl ammonium were used as the representative organo-rich, partitioning clays. The laboratory characterization techniques including XRD, TEM and …

Piezoelectric Bistable Buckled Beam Energy Harvester., Brian Edward Allgeier

Electronic Theses and Dissertations

A novel energy harvesting device design is presented to be created via microfabrication techniques. Such devices have countless applications for powering low-current electrical devices, especially wireless sensors or transmitters. This micro-electromechanical system (MEMS) design utilizes the piezoelectric response of a bistable buckled beam to gather electrical energy via ambient vibrations. While many traditional piezoelectric energy harvesters (PEH) consist of simple cantilever beam geometries, this nonlinear design utilizes inertial effects of torsional lever arms to actuate a central buckled beam to snap between its two stable states; such an abrupt strain on the piezoelectric beam potentially produces a significantly increased electrical …

Novel Processing Approaches For Thin Film Solar And Related Technologies., Brandon Lavery

Electronic Theses and Dissertations

A growing population along with developing nations are increasing the demand for energy. The International Energy Agency forecasts a global electricity demand increase of 70 percent by 2040. This is an increase from nearly 18 TW to over 30 TW. The sun can be a great clean source of achieving this energy demand. Despite the large solar industry development, the market is still growing as solar energy only accounted for 0.87% of the global energy production in 2013. The opportunity exists to manufacture more affordable solar energy that can penetrate more of the global energy market. In this dissertation, a …

Optimal Control-Based Inverse Determination Of Electrode Distribution For Electroosmotic Micromixer, Yuan Li, Yongbo Deng, Zhenyu Liu, Teng Zhou, Yihui Wu, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

This paper presents an optimal control-based inverse method used to determine the distribution of the electrodes for the electroosmotic micromixers with external driven flow from the inlet. Based on the optimal control method, one Dirichlet boundary control problem is constructed to inversely find the optimal distribution of the electrodes on the sidewalls of electroosmotic micromixers and achieve the acceptable mixing performance. After solving the boundary control problem, results are also provided to demonstrate the effectiveness of the proposed method; the step-shaped distribution of the external electric potential imposed on the sidewalls is obtained, and the electrodes with an interlaced arrangement …

Analysis And Modeling Of The Growth Of Intermetallic Compounds In Aluminum–Steel Joints, Gang Zhang, Manjiao Chen, Yu Shi, Jiankang Huang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we experimentally and numerically studied the microstructures and growth of intermetallic compounds (IMCs) formed in Al–Fe (aluminum–steel) joints welded by a pulsed double electrode gas metal arc welding (DE-GMAW)-brazing method. The IMCs consist of Fe₂Al₅ and FeAl₃, with Fe₂Al₅ being the main compound in the joints. The thickness of an IMC layer increases with an increase of the welding current (heat input) into the base metal. EBSD measurement suggests that the preferred crystal orientation of the Fe₂Al₅ IMC likely provides the necessary path for Al atoms …

Effects Of Iron Concentration And Redox States On Failure Of Boron-Free E-Glass Fibres Under Applied Stress In Different Conditions, Qingwei Wang, Richard K. Brow, Hong Li, Erica Ann Ronchetto

Materials Science and Engineering Faculty Research & Creative Works

Hydrolysis resistance of boron-free E-glass fiber with different total iron oxide (Fe₂O₃) concentrations, iron redox index and durations of fiber ageing up to 180 days at 50◦C with 50% relative humidity (RH) was studied. The effect of ageing on the fibre failure measured in two different test environments was examined by using two-point bending method. Based on the differences in failure strains of the fibres obtained from the two conditions as a function of ageing time, the Griffith theory of solid fracture was applied to estimate glass surface energy difference in ageing conditions. The results showed …

Secure Transmission With Large Numbers Of Antennas And Finite Alphabet Inputs, Yongpeng Wu, Jun Bo Wang, Jue Wang, Robert Schober, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate secure transmission over the large-scale multiple-antenna wiretap channel with finite alphabet inputs. First, we investigate the case where instantaneous channel state information (CSI) of the eavesdropper is known at the transmitter. We show analytically that a generalized singular value decomposition (GSVD)-based design, which is optimal for Gaussian inputs, may exhibit a severe performance loss for finite alphabet inputs in the high signal-to-noise ratio regime. In light of this, we propose a novel Per-Group-GSVD (PG-GSVD) design, which can effectively compensate the performance loss caused by the GSVD design. More importantly, the computational complexity of the PG-GSVD …

Biomechanical Testing Of An Exercise For Strengthening The Proximal Femur., Alyssa Osbourne

Electronic Theses and Dissertations

Based on the principles of cutting edge bone remodeling research, a unique therapeutic exercise device was designed specifically to improve bone quality at the most critical location of the proximal femur prone to fracture: the superior-lateral femoral neck where the fracture first initiates during a fall. The exercise/device is intended to work by inducing enough strain in the bone to stimulate the body’s natural bone remodeling mechanisms to increase bone density in the proximal femur and consequently prevent a fracture from arising if a fall to the side does occur.

In order to test the proposed exercise, experiments simulating the …

Custom Software For The 3d Printing Of Patient Specific Plate Bending Templates In Pelvic Fracture Repair., Gordon B Lents

Electronic Theses and Dissertations

The purpose of this work is to reduce the operative time and blood loss incurred during open reduction and internal fixation (ORIF) of traumatic pelvic injuries through the creation of patient specific bending templates for reconstruction plates. These templates are 3D printed in a resin capable of being sterilized and taken into the operating room so that bending may be performed by the surgeon before the patient is opened or by another team member in parallel with the surgeon.

A novel software extension was created in 3D modeling software to allow a surgeon to individually position screws on a pelvic …

Algan/Gan Hemt By Magnetron Sputtering System, Roman Garcia Perez

Theses and Dissertations

In this thesis, the growth of the semiconductor materials AlGaN and GaN is achieved by magnetron sputtering for the fabrication of High Electron Mobility Transistors (HEMTs). The study of the deposited nitrides is conducted by spectroscopy, diffraction, and submicron scale microscope methods. The preparation of the materials is performed using different parameters in terms of power, pressure, temperature, gas, and time. Silicon (Si) and Sapphire (Al2O3) wafers are used as substrates. The chemical composition and surface topography of the samples are analyzed to calculate the materials atomic percentages and to observe the devices surface. The instruments used for the semiconductors …

Development Of Lower Rio Grande River Water Quality Transportation Numerical Model For Bi-National River Management, Jose O. Gonzalez

Theses and Dissertations

Traditionally, water quality modelling has focused on modelling individual water bodies. However, water quality management problems must be analyzed at the larger scale to include influences from various water bodies that are interconnected. This paper provides a study on the hydrologic and quality transportation calculation by developing a hydrodynamic (unsteady state) channel routing model using a water-balanced approach. A one dimension Lagrangian river model was developed and applied to the 210 plus miles for the lower Rio Grande River Basin from the Falcon Dam to the head water of Brownsville that pours onto the Gulf of Mexico. This model can …

Multi-Functional System For Biomedical Application Using Ac Electrokinetics, Rakesh Guduru

Theses and Dissertations

Manipulation of fluids in a small volume is often a challenge in the field of Microfluidics. While many research groups have addressed this issue with robust methodologies, manipulating fluids remains a scope of study due to the ever-changing technology (Processing Tools) and increase in the demand for “Lab-On-a-Chip” devices in biological applications. This thesis peruses the flow pattern of the orthogonal electrode pattern and circular electrode providing, examples of the flow patterns and the process micromixing. Characteristics of a multifunctional system were demonstrated using orthogonal electrode and circular electrode patterned device. Conductivity of the fluids were chosen such they reflect …

Characterization Of Lift And Drag On Two Dimensional Airfoils With And Without Sinusoidal Leading Edges, Gregorio I. Acosta

Theses and Dissertations

An experimental investigation was taken on a 63-021 NACA airfoil, to characterize lift and drag and how the effects of sinusoidal leading edges affect the aerodynamic properties. A theoretical model is also purposed by implementing a perturbation on thin-airfoil theory.

Two sets of airfoils were machined and tested inside a low-speed open circuit wind tunnel. Data from a pressure scanner and particle image velocity will give an insight of how the modified leading edges affect the aerodynamic properties. A Fourier series expansion was used to solve for the lifting-line model, by use of thin-airfoil theory and complex number theory.

The Effect Of Surface Roughness Modifications And Chitosan Surface Coatings On Biofilm Formation For Prevention Of Orthopaedic Infections, Nathan Dewayne Smith

All Theses

Infections have been reported to occur in up to 91% of patients after orthopaedic procedures. Many of these infections are caused by bacterial biofilm growth on the surface of the implanted device. Surface modifications of fracture fixation implants have been taken into consideration in order to reduce infection rates and improve clinical results in orthopaedic procedures. Effective surface treatments will also reduce the need for antibiotics and prevent formation of drug-resistant bacteria. Titanium alloy sample discs (N=144) were prepared with six surface roughness treatments through polishing as well as with four different concentrations of chitosan through spin coating. In vitro …

Security For 5g Mobile Wireless Networks, Dongfeng Fang, Yi Qian, Rose Qingyang Hu

Department of Electrical and Computer Engineering: Faculty Publications

The advanced features of 5G mobile wireless network systems yield new security requirements and challenges. This paper presents a comprehensive survey on security of 5G wireless network systems compared to the traditional cellular networks. The paper starts with a review on 5G wireless networks particularities as well as on the new requirements and motivations of 5G wireless security. The potential attacks and security services with the consideration of new service requirements and new use cases in 5G wireless networks are then summarized. The recent development and the existing schemes for the 5G wireless security are presented based on the corresponding …