Engineering Commons^™

Failure Analysis Of High Nickel Alloy Steel Seal Ring Used In Turbomachinery, Wenbo Wang

USF Tampa Graduate Theses and Dissertations

The system of upper high nickel alloying steel seal ring and lower high nickel alloying steel seal ring, installed in the grooves of turbine, can extend out and fit with the wall of valve cage, resulting in forming a good seal under the pressure. In the project, the failure steel seal ring is considered. This situation had threatened the safety of the whole steam turbine system. The purpose of this study is to identify the failure cause of the steel seal ring used in nuclear steam turbines. New high nickel steel alloy seal ring was compared with the failed seal …

Effects Of Microstructure And Alloy Concentration On The Corrosion And Tribocorrosion Resistance Of Al-Mn And We43 Mg Alloys, Hesham Y. Saleh Mraied

USF Tampa Graduate Theses and Dissertations

The design of new engineering materials resistant to both wear damage and corrosion degradation becomes increasingly demanding in complex service conditions. Unfortunately, there is typically a tradeoff between wear and corrosion resistance, even for important passive metals such as Al alloys. This is because the presence of precipitates hardens the material but at the same time lead to unfavorable galvanic coupling between the precipitates and the matrix, resulting in accelerated corrosion. This work showed that Al (or Mg) supersaturated solid solution formed using non-equilibrium methods exhibited enhanced corrosion resistance without compromising strength. For Al, alloying with Mn up to ~ …

Heat Flux Modeling Of Asymmetrically Heated And Cooled Thermal Stimuli, Matthew Hardy

USF Tampa Graduate Theses and Dissertations

Thermal sensation is one of the most dynamic stimulus-response systems in the human body. It is relied upon for safety, comfort and general equilibrium of the human body. Thermal sensation is dependent upon many variables such as area of effected skin, rate of temperature change and location of stimulation. It has been shown that certain rates of change can intensify the sensation of heating or cooling. Conversely, sufficiently low rates of change can go undetected by the skin. As such, the thermal response system can be manipulated by the proper combination of applied hot and cold stimuli. Previous research has …

Orthoplanar Spring Based Compliant Force/Torque Sensor For Robot Force Control, Jerry West

USF Tampa Graduate Theses and Dissertations

A compliant force/torque sensor for robot force control has been developed. This thesis presents methods of designing, testing, and implementing the sensor on a robotic system. The sensor uses an orthoplanar spring equipped with Hall-effect sensors to measure one component of force and two moment components. Its unique design allows for simple and cost effective manufacturing, high reliability, and compactness. The device may be used in applications where a robot must control contact forces with its environment, such as in surface cleaning tasks, manipulating doors, and removing threaded fasteners. The compliant design of the sensor improves force control performance and …

Media Velocity Considerations In Pleated Air Filtration, Frederik Carl Schousboe

USF Tampa Graduate Theses and Dissertations

Asset protection in the form of fluid filtration makes up an ever-increasing part of the civilized and industrialized world. Fluid filtration applications in the conditioned environment and life sciences are affording the world’s population a chance to better realize their potential, while industrial applications help ensure that high demand processes can be carried out safely, reliably, and effectively.

In the present work, a tool has been developed, using the computational fluid dynamics package FLUENT, to allow the designer to better predict the magnitude of geometric imperfections within a given pleat configuration.

Pleated rectangular filters, intended to improve the quality of …

Fatty Acid Biomarker Detection For Breast Cancer Using Differential Mobility Spectrometry With Non-Radioactive Ion Source, James Joseph Alberti

USF Tampa Graduate Theses and Dissertations

Differential Mobility Spectrometry (DMS) using a non-radioactive ion source (NRIS) is investigated as a possible medical diagnostic instrument for near real-time detection of breast cancer biomarkers. In previous clinical studies, concentrations of Linoleic, Palmitic and Stearic fatty acids have been observed at different levels in women with carcinoma breast cancer versus women with benign tumors or healthy women showing no signs of breast cancer. Present diagnostic methods require a biopsy of the suspect tissue and a microscopic lab analysis performed to determine its disease state. This process can take hours or days before the patient and doctor are informed of …

Interference Mitigation, Resource Allocation And Channel Control Techniques For 4g And Beyond Systems, Mustafa Harun Yilmaz

USF Tampa Graduate Theses and Dissertations

The usage of the wireless communication technologies have been increasing due to the benefits they provide in our daily life. These technologies are used in various fields such as military communication, public safety, cellular communication. The current systems might not be sufficient to meet the increasing demand. Therefore, the new solutions such as the usage of smart antennas have been proposed to satisfy this demand. Among different solutions, cognitive heterogeneous networks (HetNets) have been recently introduced as a promising one to meet the high user demand. In cognitive Hetnets, there are secondary base stations (SBSs) with secondary users (SUs) and …

Simulation Of Hemiparetic Function Using A Knee Orthosis With Variable Impedance And A Proprioception Interference Apparatus, Christina-Anne Kathleen Lahiff

USF Tampa Graduate Theses and Dissertations

Individuals with stroke have neuromuscular weakness or paralysis on one side of the body caused by some muscles disengaging and overexciting other muscles. Hyperextension of the knee joint and complete lack of plantar flexion of the ankle joint are common symptoms of stroke. This thesis encompasses the simulation of hemiparetic function using both a knee orthosis with variable impedance, specifically in terms of stiffness and damping, and the Proprioception Interference Apparatus.

The section regarding the knee orthosis with variable impedance focuses on the creation and implementation of a small, lightweight, and adjustable orthotic device to be positioned around the knee …

Electrochemical Methods To Characterize Drilled Shaft Deficiencies, Sarah Jo Mobley

USF Tampa Graduate Theses and Dissertations

In recent years drilled shafts have become the preferred foundation method for marine bridges. Typically, the drilled shaft is selected over traditional driven piles due to soil strata encountered, construction economy, increased lateral stiffness requirements, and/or vibration control considerations. The most critical component in drilled shaft construction is borehole stabilization. Wall sloughing or groundwater inclusion can have devastating effects on the strength of the finished shaft however recent research has shown that the materials, more specifically the slurry, used to accomplish stabilization may be having a negative impact on the durability of the finished product. This thesis investigates the durability …

Opportunities To Mainstream Gender In Water And Wastewater Infrastructure Projects: A Case Study In Barbados, Wainella Isaacs

USF Tampa Graduate Theses and Dissertations

According to the World Resources Institute, Barbados is one of seven Caribbean countries ranked as being the most water stressed territories in the world. Prevailing drought conditions for the period 2010-2016 further compromised its water security while confirming predictions of a drier regional Caribbean climate. The simultaneous failing of at least 50-year-old water infrastructure at many points in the distribution network adds to these water stress conditions, and presents a financial burden to the local water utility in the form of lost revenues, and increased energy consumption for pumping.

Climate change and its impacts are not gender-neutral, and water infrastructure …

Optimal Bidding Strategy For A Strategic Power Producer Using Mixed Integer Programming, Sayed Abdullah Sadat

USF Tampa Graduate Theses and Dissertations

The thesis focuses on a mixed integer linear programming (MILP) formulation for a bi-level mathematical program with equilibrium constraints (MPEC) considering chance constraints. The particular MPEC problem relates to a power producer’s bidding strategy: maximize its total benefit through determining bidding price and bidding power output while considering an electricity pool’s operation and guessing the rival producer’s bidding price. The entire decision-making process can be described by a bi-level optimization problem. The contribution of our thesis is the MILP formulation of this problem considering the use of chance constrained mathematical program for handling the uncertainties.

First, the lower-level poor operation …

Engineered Nanocomposite Materials For Microwave/Millimeter-Wave Applications Of Fused Deposition Modeling, Juan De Dios Castro

USF Tampa Graduate Theses and Dissertations

A variety of high-permittivity (high-k) and low-loss ceramic-thermoplastic composite materials as fused deposition modeling (FDM) feedstock, based on cyclo-olefin polymer (COP) embedded with sintered ceramic fillers, have been developed and investigated for direct digital manufacturing (DDM) of microwave components. The composites presented in this dissertation use a high-temperature sintering process up to 1500°C to further enhance the dielectric properties of the ceramic fillers. The electromagnetic (EM) properties of these newly developed FDM composites were characterized up to the Ku-band by using the cavity perturbation technique. Several models for prediction of the effective relative dielectric permittivity of composites based …

Recombinant Elastin Based Nanoparticles For Targeted Gene Therapy, Dagmara Anne Monfort

USF Tampa Graduate Theses and Dissertations

Gene therapy is a technique used to inactivate, replace or insert a corrective copy of a defective gene in order to help diseased tissues to function properly. Gene therapy is a promising treatment for many diseases cancer, cystic fibrosis, and Parkinson’s. There are different methods to introduce a gene to the cell; one of them is the use of viruses. Among viruses, lentiviruses have been popular vectors for gene delivery due to their efficient mode of gene delivery. However, the non-specific delivery of genes associated with viruses may result in undesirable side effects. Here, we propose a heterogeneous nanoparticle delivery …

Impact Force Reduction Using Variable Stiffness With An Optimal Approach For Jumping Robots, Juan Manuel Calderon Chavez

USF Tampa Graduate Theses and Dissertations

Running, jumping and walking are physical activities that are performed by humans in a simple and efficient way. However, these types of movements are difficult to perform by humanoid robots. Humans perform these activities without difficulty thanks to their ability to absorb the ground impact force. The absorption of the impact force is based on the human ability to vary muscles stiffness.

The principal objective of this dissertation is to study vertical jumps in order to reduce the impact force in the landing phase of the jump motion of humanoid robots. Additionally, the impact force reduction is applied to an …

Impedance Optimized Electric Pulses For Enhancing Cutaneous Gene Electrotransfer, Reginald Morley Atkins

USF Tampa Graduate Theses and Dissertations

Electric field mediated gene delivery modalities have preferable safety profiles with the ability to rapidly transfect cells in vitro and in vivo with high efficiency. However, the current state of the art has relied on trial and error studies that target the average cell within a population present in treated tissue to derive electric pulse parameters. This results in fixed gene electrotransfer (GET) parameters that are not universally optimum. Slow progress towards the validation of a mechanism that explains this phenomena has also hindered its advancement in the clinic. To date, GET methods utilizing feedback control as a means to …

Catalytic Upgrading Of Biogas To Fuels: Role Of Reforming Temperature, Oxidation Feeds, And Contaminants, Nada Elsayed

USF Tampa Graduate Theses and Dissertations

Global energy demands are constantly increasing and fossil fuels are a finite resource. The shift towards alternative, more renewable and sustainable fuels is inevitable. Furthermore, the increased emissions of greenhouse gases have forced a pressing need to find cleaner, more environmentally friendly sources of fuel. Biomass energy is a promising alternative fuel because it offers several important advantages. It is a renewable energy form, it comes from many sources and produces biogas (CH₄ and CO₂). Furthermore, it can have a zero carbon footprint; this is due to the fact that the carbon produced is from the same …