Engineering Commons^™

Processing Of Advanced Two-Stage Cigs Solar Cells, Manikandan Sampathkumar

USF Tampa Graduate Theses and Dissertations

An advancement of the two stage growth recipe for the fabrication of CIGS solar cells was developed. The developed advancement was inconsistent in producing samples of similar stoichiometry. This was a huge barrier for up scaling the process as the behavior of devices would be different due to variation in stoichiometry. Samples with reproducible stoichiometry were obtained once the heating rate of elements, selenium in particular was better understood. This is mainly attributed to the exponential increase of selenium flux after its evaporation temperature. Monitoring the selenium flux was vital in getting constant selenium fluxes. Few changes to the growth …

The Impact Of Organizations' Collaboration Strategies And Alliance Network Positions On Invention Performance, Fethullah Caliskan

USF Tampa Graduate Theses and Dissertations

This research investigates the impact of organizations' collaboration strategies and network positional variables on invention performance. Organizations, particularly those pursuing a differentiation strategy, are motivated to introduce novel products and services in order to remain competitive. Thus, two questions of interest to such organizations regarding the network dynamics of the invention process are: 1) What kind of strategies allow them to attain superior invention results? 2) What is the most advantageous structural positioning in a collaborative network of innovators? Three independent studies attempt to find answers to these questions by using three complementary study approaches.

In the first study, in …

Full 3d Reconstruction From Multiple Rgb-D Cameras, Owen Watson

USF Tampa Graduate Theses and Dissertations

This thesis describes a novel procedure for achieving full 3D reconstruction from multiple RGB-D cameras configured such that the amount of overlap between views is low. Overlap is used to describe the portion of a scene that is common in a pair of views, and is considered low when at most 50% of the scene is common. Compatible systems are configured such that interpreting cameras as nodes and overlap as edges, a connected undirected graph can be constructed. The fundamental goal of the proposed procedure is to calibrate a given system of cameras. Calibration is the process of finding the …

Predicting The Clinical Outcome In Patients With Traumatic Brain Injury Using Clinical Pathway Scores, Jennifer Lorena Mendoza Alonzo

USF Tampa Graduate Theses and Dissertations

The Polytrauma/TBI Rehabilitation Center (PRC) of the Veterans Affairs Hospital (VAH) treats patients with Traumatic Brain Injury (TBI). These patients have major motor and cognitive disabilities. Most of the patients stay in the hospital for many months without major improvements. This suggests that patients, family and the VAH could benefit if healthcare provider had a way to better assess or "predict" patients' progression. The individual progress of patients over time is assessed using a pre-defined multi-component performance measure Functional Independence Measures (FIM) at admission and discharge, and a semi-quantitative documentation parameter Clinical Pathway (CP) at weekly intervals. This work uses …

Myoglobin Detection On Sic: Immunosensor Development For Myocardial Infarction, Alexandra Oliveros Villalba

USF Tampa Graduate Theses and Dissertations

Silicon carbide (SiC) has been around for more than 100 years as an industrial material and has found wide and varied applications because of its unique electrical and thermal properties. In recent years there has been increased attention on SiC as a viable material for biomedical applications. Among these applications are those where SiC is used as a substrate material for biosensors and biotransducers, taking advantage of its surface chemical, tribological and electrical properties.

In this work we have used the proven bio- and hema-compatibility of SiC to develop a viable biorecognition interface using SiC as the substrate material for …

Novel Models And Algorithms For Uncertainty Management In Power Systems, Long Zhao

USF Tampa Graduate Theses and Dissertations

This dissertation is a collection of previously-published manuscript and conference papers. In this dissertation, we will deal with a stochastic unit commitment problem with cooling systems for gas generators, a robust unit commitment problem with demand response and uncertain wind generation, and a power grid vulnerability analysis with transmission line switching. The latter two problems correspond to our theoretical contributions in two-stage robust optimization, i.e., how to efficiently solve a two-stage robust optimization, and how to deal with mixed-integer recourse in robust optimization. Due to copyright issue, this dissertation does not include any methodology papers written by the author during …

Energy Efficient Context-Aware Framework In Mobile Sensing, Ozgur Yurur

USF Tampa Graduate Theses and Dissertations

The ever-increasing technological advances in embedded systems engineering, together with the proliferation of small-size sensor design and deployment, have enabled mobile devices (e.g., smartphones) to recognize daily occurring human based actions, activities and interactions. Therefore, inferring a vast variety of mobile device user based activities from a very diverse context obtained by a series of sensory observations has drawn much interest in the research area of ubiquitous sensing. The existence and awareness of the context provides the capability of being conscious of physical environments or situations around mobile device users, and this allows network services to respond proactively and intelligently …

Towards Interference-Immune And Channel-Aware Multicarrier Schemes: Filters, Lattices, And Interference Issues, Alphan Sahin

USF Tampa Graduate Theses and Dissertations

In this dissertation, multicarrier schemes are reviewed within the framework of Gabor Systems. Their fundamental elements; what to transmit, i.e., symbols, how to transmit, i.e., filters or pulse shape, and where/when to transmit, i.e., lattices are investigated extensively. The relations between different types of multicarrier schemes are discussed.

Within the framework of Gabor systems, a new windowing approach, edge windowing, is developed to address the out-of-band (OOB) radiation problem of orthogonal frequency division multiplexing (OFDM) based multicarrier schemes. To the best of our knowledge, for the first time, the diversity on the range of the users is exploited to suppress …

Novel Approach Of Using Polyvinylidene Fluoride Langmuir-Schaefer Film On Graphene-Polyaniline Nanocomposite For Supercapacitor Applications, Venkata Priyanka Bolisetty

USF Tampa Graduate Theses and Dissertations

Supercapacitors are well known for their improvised power density compared to batteries. Ongoing research is mainly focused on improving the energy density of supercapacitors by using different electrode material nanocomposites. The recent research has revealed that graphene (G)-polyaniline (PANI) nanocomposite could be a promising material for supercapacitor applications. The supercapacitor is also associated with self-leakage current regardless of any electrode material. The main objectives of the project are to: (i) synthesize highly fabricate supercapacitor based of G-PANI electrode; (ii) improve the energy density of supercapacitor by applying ultrathin monolayer/monolayers film electrode surface. It is crucial to either improve or retain …

Design Of An Advanced Lighting Measurement System For Roadway Safety, Mathew Johnson

USF Tampa Graduate Theses and Dissertations

Roadway illumination is a vital component of safety while driving during the night. There are regulations in place to ensure all publicly maintained roads are properly lit, but the validation process is too time consuming, costly, and dangerous for adequate data collection studies. The work in this thesis is aimed toward remedying this problem by creating an Advanced Lighting Measurement System (ALMS) capable of recording illumination readings while traveling at normal driving speeds. This solution is based on the Arduino Uno development board, a cost effective yet powerful embedded platform. This thesis involves collecting data along 100 centerline miles of …

Robotic Swarming Without Inter-Agent Communication, Daniel Jonathan Standish

USF Tampa Graduate Theses and Dissertations

Many physical and algorithmic swarms utilize inter-agent communication to achieve advanced swarming behaviors. These swarms are inspired by biological swarms that can be seen throughout nature and include bee swarms, ant colonies, fish schools, and bird flocks. These biological swarms do not utilize inter-agent communication like their physical and algorithmic counterparts. Instead, organisms in nature rely on a local awareness of other swarm members that facilitates proper swarm motion and behavior. This research aims to pursue an effective swarm algorithm using only line-of-sight proximity information and no inter-agent communication. It is expected that the swarm performance will be lower than …

A Multi-Parameter Functional Side Channel Analysis Method For Hardware Trojan Detection In Untrusted Fpga Bitstreams, Christopher William Bell

USF Tampa Graduate Theses and Dissertations

Hardware Trojan Horses (HTHs or Trojans) are malicious design modifications intended to cause the design to function incorrectly. Globalization of the IC development industry has created new opportunities for rogue agents to compromise a design in such a way. Offshore foundries cannot always be trusted, and the use of trusted foundries is not always practical or economical. There is a pressing need for a method to reliably detect these Trojans, to prevent compromised designs from being put into production.

This thesis proposes a multi-parameter analysis method that is capable of reliably detecting function-altering and performance-degrading Trojans in FPGA bitstreams. It …

Packet Coalescing And Server Substitution For Energy-Proportional Operation Of Network Links And Data Servers, Mehrgan Mostowfi

USF Tampa Graduate Theses and Dissertations

Electricity generation for Information and Communications Technology (ICT) contributes over 2% of the human-generated CO2 to the atmosphere. Energy costs are rapidly becoming the major operational expense for ICT and may soon dwarf capital expenses as software and hardware continue to drop in price. In this dissertation, three new approaches to achieving energy-proportional operation of network links and data servers are explored.

Ethernet is the dominant wireline communications technology for Internet connectivity. IEEE 802.3az Energy Efficient Ethernet (EEE) describes a Low Power Idle (LPI) mechanism for allowing Ethernet links to sleep. A method of coalescing packets to consolidate link idle …

Synthesis, Characterization And Applications Of Barium Strontium Titanate Thin Film Structures, Supriya Ashok Ketkar

USF Tampa Graduate Theses and Dissertations

Barium Strontium Titanate (BST) based ferroelectric thin film devices have been popular over the last decade due to their versatile applications in tunable microwave devices such as delay lines, resonators, phase shifters, and varactors. BST thin films are promising candidates due to their high dielectric constant, tunability and low dielectric loss. Dielectric-tunable properties of BST films deposited by different deposition techniques have been reported which study the effects of factors, such as oxygen vacancies, film thickness, grain size, Ba/Sr ratio, etc. Researchers have also studied doping concentrations, high temperature annealing and multilayer structures to attain higher tunability and lower loss. …

A Methodology For Scheduling Operating Rooms Under Uncertainty, Marbelly Paola Davila

USF Tampa Graduate Theses and Dissertations

An operating room (OR) is considered to be one of the most costly functional areas within hospitals as well as its major profit center. It is known that managing an OR department is a challenging task, which requires the integration of many actors (e.g., patients, surgeons, nurses, technicians) who may have conflicting interests and priorities.

Considering these aspects, this dissertation focuses on developing a simulation based methodology for scheduling operating rooms under uncertainty, which reflects the complexity, uncertainty and variability associated with surgery.

We split the process of scheduling ORs under uncertainty into two main components. First, we designed a …

Fpca Based Human-Like Trajectory Generating, Wei Dai

USF Tampa Graduate Theses and Dissertations

This thesis presents a new human-like upper limb and hand motion generating method. The work is based on Functional Principal Component Analysis and Quadratic Programming. The human-like motion generating problem is formulated in a framework of minimizing the difference of the dynamic profile of the optimal trajectory and the known types of trajectory. Statistical analysis is applied to the pre-captured human motion records to work in a low dimensional space. A novel PCA FPCA hybrid motion recognition method is proposed. This method is implemented on human grasping data to demonstrate its advantage in human motion recognition. One human grasping hierarchy …

Vapor-Liquid-Solid(Vls) Grown Silica (Siox) Nanowires As The Interface For Biorecognition Molecules In Biosensors, Eduardo Murphy-Pérez

USF Tampa Graduate Theses and Dissertations

SiOx nanowires grown through the VLS mechanism were electrophoretically deposited on top of Au electrodes. GOx was immobilized using APTES and the EDC-NHS chemistry. Cyclic Voltammetry was used as the method to characterize the electrodes through their processing steps, and CV was also used to detect glucose in a PBS based solution. Ferro-Ferri Cyanide couple was used as the mediator.

A Study On The Optimization Of Dye-Sensitized Solar Cells, Md Imran Khan

USF Tampa Graduate Theses and Dissertations

Considering biocompatibility, the Dye Sensitized Solar Cell (DSC) based on titanium dioxide should play a major role in the future of solar energy. In this ongoing study, different components and ambient process conditions for the fabrication of were investigated. Titanium dioxide substrate thickness and morphology was found to have a direct impact on the cell efficiency. Scanning Electron Microscopy (SEM) was used to investigate the TiO2 nanostructure. Different chemical treatments and electrolytes were also explored towards optimizing the cell performance. A group of porphyrin based organic dyes were synthesized and evaluated. Standard solar cell characterization techniques such as current-voltage and …

Thermal Infrared Reflective Metal Oxide Sol-Gel Coatings For Carbon Fiber Reinforced Composite Structures, Brandon Demar Richard

USF Tampa Graduate Theses and Dissertations

Recent trends in composite research include the development of structural materials with multiple functionalities. In new studies, novel materials are being designed, developed, modified, and implemented into composite designs. Typically, an increase in functionality requires additional material phases within one system. The presence of excessive phases can result in deterioration of individual or overall properties. True multi-functional materials must maintain all properties at or above the minimum operating limit. In this project, samples of antimony and cobalt-doped tin oxide (ATO(Co2O3)) sol-gel solutions are used to coat carbon fibers and are heat treated at a temperature range of 200 - 500 …

Properties Of Peg, Ppg And Their Copolymers Influence On The Gap-Fill Characteristics Of Damascene Interconnects, Kevin Ryan

Legacy Theses & Dissertations (2009 - 2024)

A laboratory scale plating cell was built that provided reproducible bottom-up fill results for the electrochemical deposition of copper in damascene features. Several techniques used in the full wafer plating tool were incorporated into the setup to accurately control the process conditions. These techniques included but were not limited to a voltage controlled `hot-entry' step, a custom coupon holder to allow sample rotation, a secondary thief electrode and an automatic entry system. The results of qualification experiments are presented to demonstrate that precise control was realized along with repeatable partial fill plating results. The qualified setup was then used to …

Ion Beam Modification Of Single Crystal Sapphire For High Temperature Optical Waveguiding, William Spratt

Legacy Theses & Dissertations (2009 - 2024)

High temperature environments (>1000°C) provide a significant challenge for fiber optic based sensing due to the poor physical properties of silica fiber at elevated temperature. Not only does silica soften above 1000°C, but the dopants that are responsible for the refractive index change between the core and cladding diffuse, reducing the fibers effectiveness as a waveguide. Single-crystal sapphire fiber has the potential to supplement fiber sensing at high temperature however sapphire fiber is unclad and no cladding methods exist that withstand high temperatures. In addition to higher losses the lack of a cladding also leads to decreased sensitivity due …

Surface Plasmonic Lens Driven Photoelectron Source For Multi-Beam Applications, Heon Joon Choi

Legacy Theses & Dissertations (2009 - 2024)

Surface plasmon polariton (SPP) assisted photoelectron source array is proposed for use in distributed multiple electron beam lithography applications. Individual source is composed of a metal/dielectric surface structure with concentric circular grooves of subwavelength width surrounding a sub-wavelength aperture. Such optical power concentrators, called "plasmonic lenses", collect light incident over a broad area by converting it to surface electromagnetic waves, specifically SPP's, through diffraction by the sub-wavelength grooves surrounding the aperture. Through constructive interference of the generated SPPs between neighboring grooves, controlled by the periodicity of the grooves, high optical power densities can be achieved at the center of the …

Novel Resist Systems For Euv Lithography : Ler, Chain-Scission, Nanoparticle And More, Brian Cardineau

Legacy Theses & Dissertations (2009 - 2024)

Extreme Ultraviolet (EUV) lithography is currently the best option for replacing 193-nm lithography in future IC fabrication. For EUV to be successful, however, there are a number of challenges that must be overcome. Current resist designs struggle to meet the demands of future lithography nodes. We propose the best way to overcome these obstacles is through the design of novel resist systems.

Ion Beam Nano-Engineering Of Erbium Doped Silicon For Enhanced Light Emission At 1.54 Microns, Sebastian Naczas

Legacy Theses & Dissertations (2009 - 2024)

Erbium doped silicon is of great interest as a potential light source in Silicon Photonics research due to its light emission at 1.54 μm, which corresponds to the minimal loss of optical transmission in silica fibers for telecommunications. In this thesis a basic mechanism for excitation and de-excitation of Er in Si is reviewed. Based on such fundamental understanding, an innovative approach is proposed and implemented to improve Er luminescence properties through the formation of metal nanoparticles via impurity gettering in Si nanocavities.

Study Of Nickel Silicide Formation By Physical Vapor Deposition Techniques, Shanti Pancharatnam

Legacy Theses & Dissertations (2009 - 2024)

Metal silicides are used as contacts to the highly n-doped emitter in photovoltaic devices. Thin films of nickel silicide (NiSi) are of particular interest for Si-based solar cells, as they form at lower temperature and consume less silicon. However, interfacial oxide limits the reduction in sheet resistance. Hence, different diffusion barriers were investigated with regard to optimizing the conductivity and thermal stability.

White-Light And Infrared Emission From Sicxoy-Based Materials, Vasileios Nikas

Legacy Theses & Dissertations (2009 - 2024)

The development of a Si-based light source has attracted a high level of attention due to its potential unique advantages. For one, the monolithic integration of photonics on on-chip level along with the microelectronics devices would enhance the data processing rate. Additionally the cost per transmitted/processed information capacity can be significantly reduced.

Control Over Variability In Nonvolatile Hafnium-Oxide Resistive-Switching Memory Based On Modeling Of The Switching Processes, Brian Jerad Butcher

Legacy Theses & Dissertations (2009 - 2024)

Resistive random access memory (ReRAM) technology presents an attractive option for embedded non-volatile (NV) memory systems if its variability (cycle-to-cycle and device-to-device) can be controlled. This dissertation has focused on investigations to identify key mechanisms and parameters which dominate ReRAM variability, and the development of subsequent experimental and simulation-based tools to address this variability. The first component of these efforts entailed identification of the modern-day non-volatile memory technological gaps that have driven the operational requirements and challenges for resistive memory as an emerging NV memory.

Mueller Based Scatterometry And Optical Characterization Of Semiconductor Materials, Gangadhara Raja Muthinti

Legacy Theses & Dissertations (2009 - 2024)

Scatterometry is one of the most useful metrology methods for the characterization and control of critical dimensions (CD) and the detailed topography of periodic structures found in microelectronics fabrication processes. Spectroscopic ellipsometry (SE) and normal incidence reflectometry (NI) based scatterometry are the most widely used optical methodologies for metrology of these structures. Evolution of better optical hardware and faster computing capabilities led to the development of Mueller Matrix (MM) based Scatterometry (MMS). Dimensional metrology using full Mueller Matrix (16 element) scatterometry in the wavelength range of 245nm-1000nm was discussed in this work. Unlike SE and NI, MM data provides complete …

Microfluidic-Assisted Atomic Force Microscopy For The Mechanical Characterization Of Soft Biological Materials, Aaron Peter Mosier

Legacy Theses & Dissertations (2009 - 2024)

Viable methods for bacterial biofilm remediation require a fundamental understanding of biofilm mechanical properties and their dependence on dynamic environmental conditions. Mechanical test data, quantifying elasticity or adhesion, may be used to perform physical modeling of biofilm behavior, thus enabling the development of novel remediation strategies. To achieve real-time, dynamic measurements of these properties, a novel analysis platform consisting of a microfluidic flowcell device has been designed and fabricated for in situ analysis using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). The flowcell consists of microfluidic channels for biofilm establishment that are then converted into an open …

Probe Immobilization Strategies And Device Optimization For Novel Transistor-Based Dna Sensors, Nicholas Michael Fahrenkopf

Legacy Theses & Dissertations (2009 - 2024)

The research presented herein exploits the terminal phosphate group on single stranded DNA molecules for direct immobilization to surfaces utilized in semiconductor device fabrication with the end goal of transistor based DNA sensors. As a demonstration of the feasibility of this immobilization strategy DNA immobilization to a variety of surfaces was evaluated for usefulness in biosensor applications. It was determined that DNA can be directly immobilized to a variety of semiconductor surfaces through the terminal phosphate group. Further, this immobilization allows for the hybridization of the immobilized DNA to complementary target in solution. The immobilization of DNA to hafnium dioxide …