Digital Commons Network^™

Optimal Design Of An Accelerated Degradation Experiment With Reciprocal Weibull Degradation Rate, Indira Polavarapu

USF Tampa Graduate Theses and Dissertations

To meet increasing competition, get products to market in the shortest possible time, and satisfy heightened customer expectations, products must be made more robust and fewer failures must be observed in a short development period. In this circumstance, assessing product reliability based on degradation data at high stress levels becomes necessary. This assessment is accomplished through accelerated degradation tests (ADT). These tests involve over stress testing in which instead of life product performance is measured as it degrades over time. Due to the role these tests play in determining proper reliability estimates for the product, it is necessary to scientifically …

Design Optimization Of Frp Composite Panel Building Systems: Emergency Shelter Applications, Nicholas M. Bradford

USF Tampa Graduate Theses and Dissertations

Using advanced composites, an emergency shelter system has been designed. The system parameters are hurricane resistance to 138 mph wind velocity, simple erection, light weight, high durability and rapid construction. The project involves the solicitation of design proposals from several building system manufacturers and the development of an optimized emergency shelter system. The usage is well suited to pultruded members made from fiber reinforced polymers (FRP). Due to the anisotropic nature of FRP composites, a limited amount of research has been conducted to develop design optimization techniques for panels used in construction.

This project allows for the development of optimization …

Differential Adolescent Delinquency Tolerance And The Effect Of Race And Gender, Evaristus Obinyan

USF Tampa Graduate Theses and Dissertations

The study was designed to examine the attitudes of adolescents towards the tolerance of delinquent behavior. It was postulated that there would be a differential in the tolerance of delinquent behavior by juveniles from different age, gender, and racial groups. It was hypothesized that different groups would score higher or lower on select measures or dimensions (definition, reporting, controlling, preventing, correcting) of delinquency tolerance, and that their level of tolerance of delinquency might prove useful in explaining participation in delinquency.

The focus of the study was on identification of differential attitudes of various subgroups towards the violations of norms relating …

Multi-Robot Task Allocation Using Affect, Aaron Gage

USF Tampa Graduate Theses and Dissertations

Mobile robots are being used for an increasing array of tasks, from military reconnaissance to planetary exploration to urban search and rescue. As robots are deployed in increasingly complex domains, teams are called upon to perform tasks that exceed the capabilities of any particular robot. Thus, it becomes necessary for robots to cooperate, such that one robot can recruit another to jointly perform a task. Though techniques exist to allocate robots to tasks, either the communication overhead that these techniques require prevents them from scaling up to large teams, or assumptions are made that limit them to simple domains. This …

Intelligent Telerobotic Assistance For Enhancing Manipulation Capabilities Of Persons With Disabilities, Wentao Yu

USF Tampa Graduate Theses and Dissertations

This dissertation addresses the development of a telemanipulation system using intelligent mapping from a haptic user interface to a remote manipulator to assist in maximizing the manipulation capabilities of persons with disabilities. This mapping, referred to as assistance function, is determined on the basis of environmental model or real-time sensory data to guide the motion of a telerobotic manipulator while performing a given task. Human input is enhanced rather than superseded by the computer. This is particularly useful when the user has restricted range of movements due to certain disabilities such as muscular dystrophy, a stroke, or any form of …

Design And Evaluation Of The Combined Input And Crossbar Queued (Cicq) Switch, Kenji Yoshigoe

USF Tampa Graduate Theses and Dissertations

Packet switches are used in the Internet to forward information between a sender and receiver and are the critical bottleneck in the Internet. Without faster packet switch designs, the Internet cannot continue to scale-up to higher data rates. Packet switches must be able to achieve high throughput and low delay. In addition, they must be stable for all traffic loads, must efficiently support variable length packets, and must be scalable to higher link data rates and greater numbers of ports. This dissertation investigates a new combined input and crossbar queued (CICQ) switch architecture.

Some unbalanced traffic loads result in instability …

Evaluation Of Digital Imaging Systems Used In Highway Applications, Alex Mraz

USF Tampa Graduate Theses and Dissertations

Manual pavement condition surveys are gradually replaced by more comprehensive automated surveys conducted by multi-function highway evaluation vehicles. Highway evaluation vehicles are generally equipped with laser profiling, land navigation, and imaging sub-systems. The imaging system consists of three cameras; forward-view and side-view digital area-scan cameras for capturing images of traffic signs and right-of-way safety features, and a pavement digital line-scan or area-scan camera for capturing images of the pavement surface. In addition to the 3-laser and accelerometer-based profiling system, these vehicles are also equipped with differential global positioning equipment (DGPS) and an inertial measurement unit (IMU) for cross-slope, curvature and …

Physiological Responses Of Men During The Continuous Use Of A Portable Liquid Cooling Vest, Theresa J. Medina

USF Tampa Graduate Theses and Dissertations

Heat stress is a well documented hazard across industries. The combination of environmental conditions, work demands, and clothing contribute to heat strain. Left unchecked, heat strain causes changes in an individual's physiological state that can lead to serious and fatal conditions with little warning. Although engineering and administrative controls are the first choice to abate this hazard, they frequently are not feasible. In these cases, personal cooling is often employed. There are three main types of personal cooling: liquid, air, and passive. Each has its own advantages and disadvantages.

This study focuses on continuous cooling using a portable liquid cooling …

An Empirical Analysis Of The Role Of Mitigation In Capital Sentencing In North Carolina Before And After Mckoy V. North Carolina (1990), Janine Kremling

USF Tampa Graduate Theses and Dissertations

This study focuses on the influence of mitigating circumstances on the sentencing outcome before and after the McKoy (1990) decision. In McKoy (1990) the Supreme Court decided that the jurors did not have to find mitigating circumstances unanimously. Results are reported based on a sample of North Carolina first-degree murder cases where the state sought the death penalty. Logistic regression is used to determine the importance of mitigating circumstances as predictors of jury decision-making in North Carolina, controlling for the variety of other factors that influence that decision.

The descriptive statistics show that the average number of mitigating circumstances submitted …

Feasibility Of Using Nanofiltration As A Polishing Process For Removal Of Cyanobacterial Exudates From Treated Surface Water, Anand J. Mody

USF Tampa Graduate Theses and Dissertations

Nanofiltration (NF) membrane technology is effective for removal of natural organic matter (NOM) and Disinfection By-Product (DBP) precursors from treated surface water (Allgeier et al., 1995, Chellam et al., 2000, Smith et al., 2002). However, there is a need to control other micropollutants, such as compounds released from algal blooms. In this research, the feasibility of using NF for removal of cyanobacterial exudates was evaluated as a polishing process for conventionally treated surface water.

Screening tests were conducted to compare the performance of four NF membranes, Filmtec's NF90 and NF270, and Hydranautics's LFC1 and NTR7450, for removal of NOM and …

Optimization Of The Two Stage Process For Cu(In,Ga)Se2 Solar Cells, Shirish Pethe

USF Tampa Graduate Theses and Dissertations

Copper Indium Gallium DiSelenide absorber layers are fabricated using a two stage manufacturing friendly process. The first step involves the sequential deposition of Copper and Gallium and co-deposition of indium and selenium at 275oC. This is followed by the second stage where the substrate is annealed in the presence of Selenium and a thin layer of copper is deposited to neutralize the excess Indium and Gallium on the surface to form the CIGS absorber layer. The top copper thickness as well as the time of deposition was varied to study the effect of Copper on the performance of the cells. …

Congestion-Aware Cross-Layer Design For Wireless Ad Hoc Networks, Ning, Yang

USF Tampa Graduate Theses and Dissertations

Ad hoc networks have emerged recently as an important trend of future wireless systems. The evolving wireless networks are seriously challenging the traditional OSI layered design. In order to provide high capacity wireless access and support new multimedia network, the various OSI layers and network functions should be considered together while designing the network.

In this thesis, we briefly discuss performance optimization challenges of ad hoc networks and cross-layer design. Ad hoc wireless networks were implemented by using Network Simulator NS-2 and the wireless physical, data link, dynamic source routing (DSR) routing protocol models have been included in the simulation. …

Deadlock Avoidance In Mixed Capacity Flexible Manufacturing Systems, Sridhar Mohan

USF Tampa Graduate Theses and Dissertations

This research addressed the design and implementation of a polynomial-complexity deadlock avoidance controller for a flexible manufacturing cell modeled using Colored Petri Nets. The cell model is robust to changes in the part types to be manufactured in the system and is automatically generated using the interaction of the resources in the cell and the technological capabilities of the machines. The model also captures dynamic routing flexibility options. The framework introduced separates the cell model from the control logic allowing the system designer to implement and test various control algorithms using the same cell model. The controller adopts the neighborhood …

Analysis Of Fluid Circulation In A Spherical Cryogenic Storage Tank And Conjugate Heat Transfer In A Circular Microtube, P Sharath Chandra Rao

USF Tampa Graduate Theses and Dissertations

The study considered development of a finite-element numerical simulation model for the analysis of fluid flow and conjugate heat transfer in a zero boil-off (ZBO) cryogenic storage system. A spherical tank was considered for the investigation. The tank wall is made of aluminum and a multi-layered blanket of cryogenic insulation (MLI) has been attached on the top of the aluminum. The tank is connected to a cryocooler to dissipate the heat leak through the insulation and tank wall into the fluid within the tank. The cryocooler has not been modeled; only the flow in and out of the tank to …

Development Of Surface Acoustic Wave Sensors Using Nanostructured Palladium For Hydrogen Detection, Amol V. Chaudhari

USF Tampa Graduate Theses and Dissertations

This thesis addresses the development of new gas sensor using surface acoustic wave (SAW) technology. SAW sensors detect the change in mass, modulus, and conductivity of a sensing layer material via absorption or adsorption of an analyte. The advantage of SAW sensor includes low cost, small size, high sensitivity.

We investigated the use of nano-crystalline palladium film for sensing hydrogen gas. We also investigated SAW fabrication for radio frequency (RF) range operation where high signal-to-noise ratios can be achieved. A test-bed consisting of a gas dilution system, a temperature-controlled test cell, a network analyzer, and computer-based measurement system was used …

Fuzzy C-Means Clustering Approach To Design A Warehouse Layout, Vaibhav C. Naik

USF Tampa Graduate Theses and Dissertations

Allocation of products in a warehouse is done by various storage policies. These are broadly classified into three main categories: dedicated storage, randomized storage, and class-based storage. In dedicated storage policy a product is assigned a designated slot while in random storage policy incoming product is randomly assigned a storage location close to the input/output point. Finally, the class-based storage is a mixed policy where products are randomly assigned within their fixed class. Dedicated storage policy is most commonly used in practice. While designing large warehouse layout, the product information in terms of throughput and storage level is either uncertain …

The Utilization Of Enzymes In The Synthesis And Modification Of Natural And Nonnatural Compounds: A Chemo-Enzymatic Approach To Enantiomerically Pure Compounds, Jason A. Carr

USF Tampa Graduate Theses and Dissertations

The employment of enzymes and whole cells has been important in many industries for centuries. However, it is only in the last 30 years that the use of enzymes for the synthesis of high-value fine chemicals has enjoyed increasing popularity. In fact, esterases and lipases are used almost routinely these days to provide optically active building blocks for the construction of imaginative new routes to chiral target molecules. The major topic of this work describes the utilization of enzymes (namely lipases) in the synthesis and modification of natural and non-natural compounds.

Chapter 1 outlines the strengths and weaknesses of the …

Performance Analysis Of Tcp/Ip Over High Bandwidth Delay Product Networks, Subodh Kerkar

USF Tampa Graduate Theses and Dissertations

In today's Internet scenario, the current TCP has performed reasonably well. As the Internet has scaled up in load, speed, size and connectivity by the order of six over the past fifteen years, the TCP has consistently avoided severe congestion throughout this same period. Applications involving high performance computings such as bulk-data transfer, multimedia Web streaming, and computational grids demand high bandwidth. These applications usually operate over wide-area networks and, hence, performance over wide-area networks has become a critical issue. Future applications will need steady transfer rates in the order of gigabits per second to support collaborative work. TCP, which …

Modeling Demand Uncertainty And Processing Time Variability For Multi-Product Chemical Batch Process, Rishi Darira

USF Tampa Graduate Theses and Dissertations

Most of the literature on scheduling of multi-product batch process does not consider the uncertainties in demand and variability in processing times. We develop a simulation based variable production schedule model for a multi-product batch facility assuming zero wait transfer policy and single product campaign. The model incorporates the demand uncertainties and processing time variability. The impact of demand uncertainties is evaluated in terms of total annual cost, which comprises of the backorder and inventory costs per year. The effect of variability in processing time is measured by the annual production time. We also develop a constant production schedule model …

Characterization Of P-Type Zinc Oxide Films, Madhavi Oleti Kalki Rajan

USF Tampa Graduate Theses and Dissertations

Zinc Oxide falls under the classification of transparent conductive oxides. They typical optical transmittance of Zinc Oxide is 90% in the visible wavelength region. Though stoichiometric ZnO is an insulator, due to the presence of internal defects such as Zn interstitials and Oxygen vacancies, it exists as a n-type conductor.

The other important property of ZnO which could be used by the optical field is its widebandgap. ZnO has a wide bandgap of 3.2eV -3.3eV. The additional advantage of being a direct bandgap semiconductor has increased the probability of using ZnO for short wavelength applications. These practical applications are directly …

A Comparative Analysis Of Travel Time Expenditures In The United States, Lavenia Anne Toole-Holt

USF Tampa Graduate Theses and Dissertations

Literature on transportation planning and modeling is replete with the concept of a travel time budget. According to this concept, average daily travel times tend to be relatively constant. However, evidence from the 1983 Nationwide Personal Transportation Survey and the 2001 National Household Travel Survey suggest that the average daily travel time has increased by 1.9 minutes per year.

Understanding travel time expenditures is important for forecasting travel demand, especially future vehicle miles of travel. Historically, travel demand models considered vehicle availability and income as limiting factors for travel, but going forward time may be the constraint. As individuals spend …

Characterization Of Preliminary Breast Tomosynthesis Data: Noise And Power Spectra Analysis, Madhusmita Behera

USF Tampa Graduate Theses and Dissertations

Early detection, diagnosis, and suitable treatment are known to significantly improve the chance of survival for breast cancer (BC) patients. To date, the most cost effective method for screening and early detection is screen-film mammography, which is also the only tool that has demonstrated its ability to reduce BC mortality. Full-field digital mammography (FFDM) is an extension of screen-film mammography that eliminates the need for film-processing because the images are detected electronically from their inception. Tomosynthesis is an emerging technology in digital mammography built on the FFDM framework, which offers an alternative to conventional two-dimensional mammography. Tomosynthesis produces three-dimensional (volumetric) …

An Analysis Of Travel Trends Of The Elderly And Zero-Vehicle Households In The United States, Ravi Kiran Gorti

USF Tampa Graduate Theses and Dissertations

The elderly and persons residing in zero vehicle households require better transportation services by virtue of their need for special care and lack of mobility, respectively. An analysis of the travel trends of these population cohorts is essential to determine the best ways to improve transportation facilities to better serve them. Information about location of residence, life-cycle, differences by gender, employment status, driver status, highest level of education coupled with trip information like trip rate, travel times and distances trip purpose, modal split and percent of people immobile will facilitate understanding the factors that influence trip making among these people …

Hydraulic Performance Of Polymer Modified Bentonite, Jessica A. Schenning

USF Tampa Graduate Theses and Dissertations

Bentonite clay is widely used in barrier systems due to its low hydraulic conductivity and it high swell capacity. Exposure to inorganic solutions can cause significant increases in hydraulic conductivity, due to changes in the surface chemistry and fabric. This phenomenon can be attributed to a reduction in the thickness of the double layer, due to the cation exchange capacity of the clay. The clay can be modified with polymers to render it less susceptible to chemical attack. The treatment process allows the clay to be engineered to enhance specific properties, such as permeability and sorption. In the present study, …

Analysis Of Glass Mold To Enhance Rate Of Heat Transfer, Anand Warude

USF Tampa Graduate Theses and Dissertations

Narrow Neck Press and Blow (NNPB) process is used to produce light weight bottles. The gob of molten glass is delivered to the blank mold and a specially designed narrow diameter plunger is used to form the finish or mouth and the parison as it presses upwards. Invert and final blow takes place followed by take-out and annealing. Anchor Glass Container Corp. (AGC) uses NNPB technology in their glass making plants. The problem experienced by AGC in the process is that the heat dissipation through out the mold is not uniform and hence there is a non uniform temperature distribution …

A Model For Strategic Bidding In Combined Transmission And Wholesale Energy Markets, Sanket Gupte

USF Tampa Graduate Theses and Dissertations

Motivated by deregulation in major service sectors like airlines, banking and telecommunication, the electric industry is undergoing a major transformation. However due to design inefficiencies, restructuring of the power sector, so far, has not been a major success. A lack of comprehensive quantitative models has resulted in the inability of the market designers to evaluate market performance and develop successful market designs. A comprehensive model should include market features like two-settlement system, transmission congestion, financial transmission rights (FTRs), demand elasticity, demand-side bidding and other market rules.

The contribution of this thesis includes development of an exhaustive modeling framework that includes …

Distributed Clustering For Scaling Classic Algorithms, Prodip Hore

USF Tampa Graduate Theses and Dissertations

Clustering large data sets recently has emerged as an important area of research. The ever-increasing size of data sets and poor scalability of clustering algorithms has drawn attention to distributed clustering for partitioning large data sets. Sometimes, centrally pooling the distributed data is also expensive. There might be also constraints on data sharing between different distributed locations due to privacy, security, or proprietary nature of the data. In this work we propose an algorithm to cluster large-scale data sets without centrally pooling the data. Data at distributed sites are clustered independently i.e. without any communication among them. After partitioning the …

Effects Of Aspirin And Its Derivatives In Combination With Electroporation For Drug Delivery In Cultured Cells, Jennifer Langham

USF Tampa Graduate Theses and Dissertations

The purpose of this research was to investigate the effects that aspirin (ASA) and its metabolites, salicylic acid (SA) and acetic acid (AA), have on the delivery of drugs across biological barriers when used in conjunction with electroporation. Electroporation is a technique used to enhance drug delivery across bio-membranes in which a transmembrane potential is induced into cellular membranes, resulting in the creation of aqueous pores that allow molecules to pass through the otherwise impermeable barrier. Aspirin is a widely used drug that has been used for over a century and has been proven relatively safe at normal doses as …

Robust Dock Assignments At Less-Than-Truckload Terminals, Mesut Korhan Acar

USF Tampa Graduate Theses and Dissertations

Less-than-truckload industry has a valuable potential for applications of operations research in two areas, network design and efficiency improvement within existing networks. This thesis focuses on the latter, specifically the less-than-truckload terminals where cross docking operations occur.

The assignment of incoming trailers to inbound docks is one of the critical decisions that affect the performance of less-than-truckload terminals. This research reviews existing models in literature and introduces an optimal mixed integer quadratic model with the objective of generating assignments that are robust against variability in system parameters such as truck arrival and service times, terminal characteristics and trailer load content. …

A Decision Support Tool For Accepting Or Rejecting Donations In Humanitarian Relief Organizations, Francisco Javier Ruiz-Brand

USF Tampa Graduate Theses and Dissertations

With the increase in the occurrence of disasters (natural and man-made) that leave people injured, handicapped or dead, the disaster management theory is gaining more importance. As a consequence, human assistance and disaster relief organizations are managing increasingly more inventories anticipated to help people in need. Donations are the common means used by humanitarian relief organizations for procuring commodities to support some of their programs. Previous experiences have indicated that donations become a burden instead of offering relief when they do not match actual victims' needs. Accepting or rejecting donations is a key issue that can produce not only economic …