Engineering Commons^™

Surface Plasmon Polaritons And Waveguide Modes At Structured And Inhomogeneous Surfaces, Javier Polanco

Open Access Theses & Dissertations

In chapter 1, properties of a p-polarized surface plasmon polariton are studied, propagating circumferentially around a portion of a cylindrical interface between vacuum and a metal, a situation investigated earlier by M. V. Berry (J. Phys. A: Math. Gen. 8, (1975) 1952). When the metal is convex toward the vacuum this mode is radiative and consequently is attenuated as it propagates on the cylindrical surface. An approximate analytic solution of the dispersion relation for this wave is obtained by an approach different from the one used by Berry, and plots of the real and imaginary parts of its wave number …

Manufacturing Nerve Guidance Conduits By Stereolithography For Use In Peripheral Nerve Regeneration, Mireya Aidee Perez

Open Access Theses & Dissertations

Nerve regeneration techniques have been studied in great depth in recent years. Peripheral nerve injuries, in particular, can be caused by accidents, falls, athletic injuries, etc. Current methods of repair include direct suturing of the 2 injured nerve ends or the use of autografts, when a nerve section is taken from another area of the body. Both methods have a series of limitations which have led researchers to study alternative methods of repair. Nerve guidance conduits may provide a viable solution because they can be modified and adapted to the patient's needs. Some conduits already exist on the market and …

Inkjet Based Personalized Screening Platform For Cancer Therapy, Jorge Ivan Rodriguez

Open Access Theses & Dissertations

The new paradigm of personalized medicine is beginning to affect clinical practice. In particular, many of the advances in genomics and proteomics have made personalized screening and therapeutic inventions possible. On chip, cellomics approaches to screening and intervention are becoming more commonplace. Cancer therapies may benefit from the rise in `-omics' technologies. In addition, the availability of rapid screening data is crucial to mitigate cancer propagation and increase the possibility of patient recovery. This study is an endeavor to develop a cellomic anticancer drug screening process based on inkjet printing. Previous research has demonstrated that inkjet based screening can reliably …

Printable Biodegradable Hydrogel For Skin Wound Dressing Using Inkjet Printing Technology, Maria G. Yanez

Open Access Theses & Dissertations

Chronic wounds are becoming more frequent. Foot ulcers affect approximately 10% - 15% of patients with diabetes throughout their lifetimes, and by 2025, it is estimated the prevalence of diabetes will be 250 million people in the worldwide. There is increased potential for patients with peripheral neuropathy and peripheral vascular disease to suffer more foot injuries. These conditions reduce the normal pain sensations and healing of minor traumas, allowing the development of chronic non-healing ulcers, often preceding lower-extremity amputation. These types of wounds are very difficult to treat and sometimes take months or even years to heal because of many …

Dielectric And Complex Impedance Properties Of Tetravalent Hafnium (Hf 4+) Integrated Cobalt Ferrite, Luis Javier Sanchez

Open Access Theses & Dissertations

The work presented in this thesis was carried out to understand the effects of tetravalent hafnium (Hf4+) ion on the crystal structure and phase, surface morphology, electrical, dielectric and complex impedance properties of cobalt ferrite (CoFe2O4; CFO). Hafnium incorporated cobalt ferrite, CoFe2-xHfxO4, with x = 0.00, 0.05, 0.075, 0.10, 0.15 and 0.20 were prepared by the standard solid state ceramic synthesis method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterizations were performed to determine the structural properties. Most important aspect of this study is to explore the dielectric and complex impedance properties as a function of variable temperature (T=300-1000 …

Assessment And Evaluation Of The Dynamic Behavior Of Muscles With Special Reference To Subjects With Diabetes Mellitus, Jorge Garza-Ulloa

Open Access Theses & Dissertations

Diabetes mellitus (simply diabetes) is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. Each year, the costs of diabetes rise. Diabetes and its complications cost our national economy. Two new methods are proposed to measure the diabetes implications in the muscles of lower body: Muscle energy expenditure analysis based on the detection of muscle transition-to-fatigue, and Natural Fuzzy logic method for differential analysis in muscle/joint. Then the results are compared with the traditional method …

Structural, Optical And Electrical Properties Of Yttrium-Doped Hafnium Oxide Nanocrystalline Thin Films, Abhilash Kongu

Open Access Theses & Dissertations

Hafnium oxide (HfO2) has emerged as the most promising high-k dielectric for Metal-Oxide-Semiconductor (MOS) devices and has been highlighted as the most suitable dielectric materials to replace silicon oxide because of its comprehensive performance. In the present research, yttrium-doped HfO2 (YDH) thin films were fabricated using RF magnetron sputter deposition onto Si (100) and quartz with a variable thickness. Cross-sectional scanning electron microscopy coupled with Filmetrics revealed that film thickness values range from 700 A° to 7500 A°. Electrical properties such as AC Resistivity and current-voltage (I-V) characteristics of YDH films were studied. YDH films that were relatively thin (<1500 A°) crystallized in monoclinic phase while thicker films crystallized in cubic phase. The band gap (Eg) of the films was calculated from the optical measurements. The band gap was found to be ∼5.60 eV for monoclinic while it is ∼6.05 eV for cubic phase of YDH films. Frequency dependence of the electrical resistivity (ρac) and the total conductivity of the films were measured. Resistivity decreased (by three orders of magnitude) with increasing frequency from 100 Hz to 1 MHz, attributed due to the hopping mechanism in YDH films. Whereas, while ρac∼1Ω-m at low frequencies (100 Hz), it decreased to ∼ 104 Ω-cm at higher frequencies (1 MHz). Aluminum (Al) metal electrodes were deposited to fabricate a thin film capacitor with YDH layer as dielectric film thereby employing Al-YDH-Si capacitor structure. The results indicate that the capacitance of the films decrease with increasing film thickness. A detailed analysis of the electrical characteristics of YDH films is presented.

Optimization Of Bioprinting Process Using Design Of Experiments (Doe) And Taguchi Method, Maria Veronica Gonzalez

Open Access Theses & Dissertations

At this time there is a need for new fabrication techniques for engineering complex biological structures related to regenerative medicine, in vitro tissue analysis, and pharmaceutical testing with the purpose of placing specific cells in specific target locations. Right now, there is no enough conventional cell seeding methods that can achieve it. In order to achieve it, bio-fabrication, which is a delivery mechanism capable of placing biomaterials, cells, and bioactive macromolecules in specific target locations, comes to play an important role in this area. Among different approaches, bioprinting is one of the most useful processes that use drop-on-demand delivery mechanisms …

3d Printed Impedance Elements By Micro-Dispensing, Ubaldo Robles Dominguez

Open Access Theses & Dissertations

Micro-dispensing allows electric circuits to be "3D printed," which can be used to give 3D printed systems electronic and electromagnetic functionality. The focus of this thesis is using micro-dispensing to fabricate capacitors and inductors. 3D printed impedance elements are capable of being more easily embedded, can be used to create structural electronics, and will have extensive applications in antennas, metamaterials, frequency selective surfaces, and more. This is the first known effort to print and measure impedance elements by micro-dispensing which holds great potential for manufacturing multi-material devices.

Reduction Of Onu Buffering For Pon/Vdsl Hybrid Access Networks, Elliott Ivan Gurrola

Open Access Theses & Dissertations

Today's growing internet traffic requires service providers to offer customers faster transmission rates. To keep up with such high transmission rates, service providers need to deploy fiber optical networks. However, due to the high cost involved in deploying the fiber media, this may not prove to be a feasible solution. Instead, service providers can deploy fiber media up to a distribution point, such as a customer's block, and continue the last few hundred feet using the already deployed legacy copper wire media.

In our study we investigate downstream/upstream transmission coordination for passive optical network (PON) / Digital Subscriber Line (DSL) …

Reduced-Order Modeling Using Orthogonal And Bi-Orthogonal Wavelet Transforms, Miguel Hernandez Iv

Open Access Theses & Dissertations

It is well known that model reduction methods borrow techniques typically found in data compression, and current state-of-the-art techniques for data compression are based on the wavelet transform. Given these facts, it is surprising that model reduction using wavelets has not received much attention and has not been adequately addressed in the literature. This research seeks to determine if wavelets can be used for model reduction and if wavelet model reduction is a viable alternative to existing model reduction methods.

In this work we propose a novel method for model reduction using wavelets. Specifically, we introduce techniques for deriving wavelet …

Efficient, Scalable, Parallel, Matrix-Matrix Multiplication, Enrique Portillo

Open Access Theses & Dissertations

For the past decade, power/energy consumption has become a limiting factor for large-scale and embedded High Performance Computing (HPC) systems. This is especially true for systems that include accelerators, e.g., high-end computing devices, such as Graphics Processing Units (GPUs), with terascale computing capabilities and high power draws that greatly surpass that of multi-core CPUs. Accordingly, improving the node-level power/energy efficiency of an application can have a direct and positive impact on both classes of HPC systems.

The research reported in this thesis explores the use of software techniques to enhance the execution-time and power-consumption performance of applications executed on a …

Asynchronous Logic Design With Increased Fault Tolerance And Optimized For Subthreshold Operation, Ivan Santos

Open Access Theses & Dissertations

Synchronization has always been an essential feature in electronic circuits, in which functionality is achieved by an appropriate flow of data with respect to time. An ideal concept of logic design would require every operation to happen instantly; however, the application of this principle to electronics is governed by the laws of physics, which influence the time to execute a process. In fact, the speed at which a microprocessor can perform logic operations is determined by the time that charging and discharging capacitive loads requires, and the time that electric signals spend when traveling through the circuitry. Consequently, the variation …

Effect Of Hafnium-Incorporation On The Microstructure And Dielectric Properties Of Cobalt Ferrite Ceramics, Stephen Josiah Wells

Open Access Theses & Dissertations

The effect of hafnium ion (Hf⁴⁺) incorporation in cobalt ferrite (CFO) was studied. Samples of Hf substituted CFO ceramic (CoFe_2-xHf_xO₄), were synthesized in the laboratory with hafnium concentrations ranging from x=0.000 to x=0.200. X-ray diffraction scans show that the Hafnium CFO crystalizes in the inverse spinel phase. Inclusion of hafnium causes lattice expansion, increasing the lattice parameter from 8.374 í? for pure CoFe2O4 to 8.391 í? for the highest concentration of hafnium tested (x=0.020). The dielectric properties of CFO are greatly enhanced by inclusion of hafnium. The enhancement is due to the …

Integration Of Memristors With Mems For Dynamic Displacement Control, Sergio Fabian Almeida Loya

Open Access Theses & Dissertations

In recent years the demand for high-speed, lower power consumption and large-capacity non-volatile memories has increased. Promisingly the memristor can be used due to its special characteristic of having memory through resistance change. The memristor behavior is not limited to digital applications but it can be used in analog application as well including: memristors in chaotic circuits, amoeba's learning, neural synaptic emulation, reprogrammable and reconfigurable circuits, and for neuromorphic computers. On the other hand Micro Electro Mechanical Systems (MEMS) are small scale structures that can interact with the physical world due to their mechanical properties. These devices are widely used …

Anasic Design And Test Methodology For An Undergraduate Design And Fabrication Project, Arun Joseph Kurian

Open Access Theses & Dissertations

During the 1990's the main focus of chip design methodologies was on the timings and area constraints. Power consumption was considered significant only after a drastic increase of device densities from 130nm on as well as dramatic increases in sub threshold leakage. As technology advanced from 130nm to 90nm and below there was a significant increase in leakage current due to lower threshold voltage and the influence of the deep submicron effects. High power consumption causes different problems such as increasing the cost of the product, reducing the reliability, reducing the battery life among others. Therefore EDA tools were designed …

Analysis Of Vehicle Interactions On Interstate Highways: Discrete Choice And Linear System Approaches, Alicia Romo

Open Access Theses & Dissertations

The research in this dissertation developed statistical and linear system models to predict driving behavior according to driver attributes, vehicle characteristics, car-following dynamics and/or driving conditions. The scope of this research was limited to the interaction of two vehicles traveling in the same direction on interstate highways.

The statistical models proposed in this research investigated the contributions of the different vehicle types on the manner and likelihood of collision. Discrete choice models were used to estimate the probability of the types of collision (rear-end, angle and sideswipe) as functions of driver attributes, striking and struck vehicle types, pre-crash driving actions …