Engineering Commons^™

Halloysite Clay Nanotubes For Controlled Delivery Of Chemically Active Agents, Elshard Abdullayev

Doctoral Dissertations

In this work we explored the capabilities of halloysite nanotubes as capsules for encapsulation and controlled delivery of the chemically and biologically active substances. Halloysite is a two-layered aluminosilicate which has a predominantly hollow tubular structure in the submicron range and is chemically similar to kaolinite [1, 2].

In the first section of this work, we analyzed the structure of the halloysite nanotubes as well as its capability to encapsulate and deliver biologically and chemically active agents, similarities and differences between release characteristics of different agents and how these differences relate with their chemical structure. Models were used to describe …

Classification Of Emg Signals To Control A Prosthetic Hand Using Time-Frequesncy Representations And Support Vector Machines, Juan Manuel Fontana

Doctoral Dissertations

Myoelectric signals (MES) are viable control signals for externally-powered prosthetic devices. They may improve both the functionality and the cosmetic appearance of these devices. Conventional controllers, based on the signal's amplitude features in the control strategy, lack a large number of controllable states because signals from independent muscles are required for each degree of freedom (DoF) of the device. Myoelectric pattern recognition systems can overcome this problem by discriminating different residual muscle movements instead of contraction levels of individual muscles. However, the lack of long-term robustness in these systems and the design of counter-intuitive control/command interfaces have resulted in low …

Surface Morphology Of Platelet Adhesion Influenced By Activators, Inhibitors And Shear Stress, Melanie Groan Watson

Doctoral Dissertations

Platelet activation involves multiple events, one of which is the generation and release of nitric oxide (NO), a platelet aggregation inhibitor. Platelets simultaneously send and receive various agents that promote a positive and negative feedback control system during hemostasis. Although the purpose of platelet-derived NO is not fully understood, NO is known to inhibit platelet recruitment. NO's relatively large diffusion coefficient allows it to diffuse more rapidly than platelet agonists. It may thus be able to inhibit recruitment of platelets near the periphery of a growing thrombus before agonists have substantially accumulated in those regions.

Results from two studies in …

Nonlinear Control Strategy For A Cost Effective Myoelectric Prosthetic Hand, Cristian Federico Pasluosta

Doctoral Dissertations

The loss of a limb tremendously impacts the life of the affected individual. In the past decades, researchers have been developing artificial limbs that may return some of the missing functions and cosmetics. However, the development of dexterous mechanisms capable of mimicking the function of the human hand is a complex venture. Even though myoelectric prostheses have advanced, several issues remain to be solved before an artificial limb may be comparable to its human counterpart. Moreover, the high cost of advanced limbs prevents their widespread use among the low-income population.

This dissertation presents a strategy for the low-level of control …

An Improved Layer-By-Layer Self-Assembly Technique To Generate Biointerfaces For Platelet Adhesion Studies: Dynamic Lbl, Juan Manuel Lopez

Doctoral Dissertations

Layer-by-layer self-assembly (LbL) is a technique that generates engineered nano-scale films, coatings, and particles. These nanoscale films have recently been used in multiple biomedical applications. Concurrently, microfabrication methods and advances in microfluidics are being developed and combined to create "Lab-on-a-Chip" technologies. The potential to perform complex biological assays in vitro as a first-line screening technique before moving on to animal models has made the concept of lab on a chip a valuable research tool.

Prior studies in the Biofluids Laboratory at Louisiana Tech have used layer-by-layer and in vitro biological assays to study thrombogenesis in a controlled, repeatable, engineered environment. …

Mitigation Of Chloride And Sulfate Based Corrosion In Reinforced Concrete Via Electrokinetic Nanoparticle Treatment, Kunal Kupwade-Patil

Doctoral Dissertations

Concrete is a porous material which is susceptible to the migration of highly deleterious species such as chlorides and sulfates. Various external sources, including sea salt spray, direct seawater wetting, deicing salts and chlorides can contaminate reinforced concrete. Chlorides diffuse into the capillary pores of concrete and come into contact with the reinforcement. When chloride concentration at the reinforcement exceeds a threshold level it breaks down the passive oxide layer, leading to chloride induced corrosion. The application of electrokinetics using positively charged nanoparticles for corrosion protection in reinforced concrete structures is an emerging technology. This technique involves the principle of …

Modeling And Its Numerical Method For Micro-Scaled Diffusion -Reaction Systems In The Neuromuscular Junction, Abdul Khaliq

Doctoral Dissertations

The main subject of this research is the neuromuscular junction (NMJ). The NMJ is a biological structure composed of the interface between a neuron and a muscle cell. Currently, there is not a fully three dimensional model of diffusion-reaction processes occurring in the NMJ. Developing a useful predictive model of this structure will assist in the therapeutic efforts to restore and rehabilitate NMJ function to humans and in developing strategies to prevent damage to the NMJ. This research work developed 1D mass transport and full 3D reaction diffusion models. A new finite difference scheme is presented for solving 1D mass …

In Vivo Non-Invasive Monitoring Of Optically Resonant Metal Nanoparticles Using Multi-Wavelength Photoplethysmography, Gregory J. Michalak

Doctoral Dissertations

Nanotechnology has recently emerged as a powerful modality in many biomedical applications. In particular, several classes of nanoparticles have been employed as cancer therapy and imaging contrast agents. These particles can have architecture of varying complexity, depending on their specific application. These complex architectures are achieved by various chemical techniques usually performed in specific sequences to add complexity and functionality. One such class of nanoparticle, used in tumor treatment and as contrast agents in several optical imaging techniques, is the plasmon resonant metal nanoparticle. The most common metal used for these particles is gold because of its biocompatibility, lack of …

Elimination Of Deck Joints Using A Corrosion Resistant Frp Approach, Ashok Reddy Aleti

Doctoral Dissertations

The research presented herein describes the development of durable link slabs for jointless bridge decks based on using FRP grid for reinforcement. Specifically, the ductility of the FRP material was utilized to accommodate bridge deck deformations imposed by girder deflection, temperature variations, and concrete shrinkage. It would also provide a solution to a number of deterioration problems associated with bridge deck joints.

The design concept of the link slabs was then examined to form the basis of design for FRP grid link slabs. Improved design of FRP grid link slab/concrete deck slab interface was confirmed in the numerical analysis. The …

Analysis Of Conjugated Polymer Nanotubules Formed By Template Wetting Nanofabrication, Steven D. Bearden Jr.

Doctoral Dissertations

Semiconducting and optoelectric conjugated polymers have potential in micro and nano-electronic applications. Their widely tunable physical conformations and orientations make these polymers ideal material for engineering small scale devices. The polymers have been incorporated into several electronic devices including light-emitting diodes, solar cells, and field-effect transistors. Widespread adoption of these materials will not be a reality until the issues of poor device performance, short lifespans, and device degradation are resolved.

Nanostructures have been demonstrated to have improvements in molecular ordering and electronic transport. In the work presented here, tubular nanostructures of conjugated polymers fabricated by the template wetting nanofabrication process …

Experimental Investigation Of Flow And Heat Transfer Characteristics Of R -134a In Microchannels, Abdullahel Bari

Doctoral Dissertations

The purpose of this study was to investigate the flow and heat transfer characteristics of liquid refrigerant R-134a in rectangular microchannels. The research concentrated mostly upon single-phase experiments with limited investigation of boiling phenomenon in microchannels. Tests were performed using rectangular microchannels with hydraulic diameters ranging from 112 μm to 210 μm and aspect ratios varying approximately from 1.0 to 1.5. The Reynolds number in the experiments ranged from 1,200 to 13,000 although most data were collected in the transition and turbulent flow regimes.

The experimental data for friction factor measurement had a similar trend as predicted by macroscale theory …

Development Of A Geopolymer-Based Cementitious Coating For The Rehabilitation Of Buried Concrete Infrastructure, Carlos Montes

Doctoral Dissertations

The current research project was devoted to the incorporation of geopolymers as a new material for Trenchless projects, taking advantage of their properties in a field in which they had not been used before, providing a substantial help to municipalities to meet their rehabilitation needs. Trenchless Technologies are a family of methods, materials and equipment capable of being used for the installation of new or replacement or rehabilitation of existing underground infrastructure with minimal disruption to surface traffic, business, and other activities.

The dissertation research work described herein is divided into six primary objectives: (1) the evaluation of geopolymer as …

Dna Microarray Image Segmentation Using Active Contours Without Edges Method, Shenghua Ni

Doctoral Dissertations

The goal of this dissertation is to build a better segmentation method for DNA microarray image processing. Segmentation is a partitioning process used to separate a spot area from a non-spot area in DNA microarrays. It directly affects the accuracy of gene expression analysis in the data mining process that follows. A number of DNA microarray segmentation methods have been proposed in the area, but even modern segmentation methods seem to have accuracy problems. In this dissertation, I will present a segmentation method based on the Active Contours Without Edges (ACWE) algorithm and apply it to two types of DNA …

Integrated, Multi-Attribute Decision Support System For The Evaluation Of Underground Utility Construction Methods, John C. Matthews

Doctoral Dissertations

The dissertation research work described herein is comprised of three primary objectives: (1) the development of a rehabilitation method selection software (TAG-R) for the National Association of Sewer Service Companies (NASSCO) and its subsequent validation and combination with TAG (a sister decision support system (DSS) software developed by the author in an earlier work); (2) the development of a social cost calculator (SCC) and its validation; and (3) the development of a proposed framework for multi-segment optimization for construction methods selection using the tools developed in the first two objectives as well as additional project related data.

The selection of …