Digital Commons Network^™

Assistive Technologies For Independent Navigation For People With Blindness, Howard Kaplan

USF Tampa Graduate Theses and Dissertations

The necessity for individuals to navigate from location to location is essential to daily life. The majority of humans use sight as the main source for determining how to move through their environment. However, there is a large population of people who are either blind or living with low vision. Based on a 2017 National Health Survey there are around 27 million adult Americans that have experienced vision loss (National Center for Health Statistics, 2017). According to the Eye Diseases Prevalence Research Group there are 3.4 million Americans 40 years and older that are legally blind or visually impaired (EDPRG, …

Multi-Material Hybrid Additive And Subtractive Manufacturing Of Photonic Devices, Roger Brandon Tipton

USF Tampa Graduate Theses and Dissertations

Optoelectronics focuses on the application of electronic devices that utilize forms of electromagnetic radiation including visible light and other wavelengths including ultraviolet and infrared. Optoelectronics typically include devices that emit light and detect light. Devices created using this technology include light-emitting diodes, laser diodes, photoresistors, photodiodes, solar cells, phototransistors, and fiber optics. Fiber optic interconnects are interesting devices in that they are used in conjunction with optoelectronic devices to transmit information between individual optoelectronic components.

Optoelectronics are typically produced by traditional lithography methods including etching, writing, and printing on rigid silicon substrates for fabricating devices. Other techniques like glass or …

Dynamic Loading Directed Neural Stem Cell Differentiation, Abdullah Revaha Akdemir

USF Tampa Graduate Theses and Dissertations

Spinal cord injuries (SCI) are among the biggest challenges for medical and engineering fields in the modern era. Many people experience various accidents every year that cause major irreversible trauma in the spinal cord. Damaged neural cells caused by SCI cannot be regenerated, and patients have to live with pain, spasms, or loss of movement. Stem cell differentiation can be a potential solution to generate enough neurol cells in vitro to apply at the defective region. In this research, the impact of dynamic mechanical stimulation on the differentiation of PC-12 cell lines towards neurol cells was studied. Models to apply …

A Study Of Rf/Microwave Components Using Fused Deposition Modeling And Micro-Dispensing, Joshua A. Stephenson

USF Tampa Graduate Theses and Dissertations

The design and study of multiple RF direct digital manufactured (DDM) devices are presented in this work. A 2.45 GHz, 180°; hybrid coupler is designed to provide the space required for other system components. The coupler is designed and manufactured on a 32 mil Rogers 4003C substrate and adapted to a 100% in-fill acrylonitrile butadiene styrene (ABS) substrate. A size reduction of 66% is accomplished with a bandwidth of 16%. A DDM Ku band connector is modeled and fabricated using varying relative dielectric constants of 50% and 100% in-fill ABS. The connector maintains less than 0.45 dB of insertion loss …

A Study Of Digital Rf Phase Shifters Fabricated With Additive Manufacturing, Yaniel Vega

USF Tampa Graduate Theses and Dissertations

Digital RF phase shifters fabricated using additive manufacturing processes are presented and studied. The purpose is to explain the performance differences between phase shifters fabricated using additive manufacturing and those fabricated with conventional subtractive techniques. All phase shifters are designed to operate at a center frequency of 2.45 GHz with a 100 MHz bandwidth. The 1-bit 45° switched line phase shifters have an average insertion loss of 1.3 dB and a 220 mm² footprint, while the 1-bit 180° high-pass low-pass phase shifters have an insertion loss 1.56 dB and a 180 mm² footprint. The 4-bit high-pass low-pass, switched …

A Study Of Direct Digital Manufactured Rf/Microwave Packaging, John W.I. Stratton

USF Tampa Graduate Theses and Dissertations

Various facets of direct digital manufactured (DDM) microwave packages are studied. The rippled surface inherent in fused deposition modeling (FDM) fabricated geometries is modeled in Ansoft HFSS, and its effect on the performance of microstrip transmission lines is assessed via simulation and measurement. The thermal response of DDM microstrip transmission lines is analyzed over a range of RF input powers, and linearity is confirmed over that range.

Two IC packages are embedded into DDM printed circuit boards, and their performance is analyzed. The first is a low power RF switch, and the second is an RF front end device that …

An Experimental Study On Passive Dynamic Walking, Philip Andrew Hatzitheodorou

USF Tampa Graduate Theses and Dissertations

In this study, a previously designed passive dynamic walker (PDW) is built out of aluminum and plastic. The aim of the study was to produce an asymmetrical PDW and to compare the results to a computer simulation to validate the mathematical model. It also aimed at identifying the limitations of using additive manufacturing to create components for a PDW as well as gain insights on asymmetric systems.

Beginning with a five mass kneed model, parameters were varied to produce up to a nine mass kneed model solution. The nine mass model allows more variability in added mass locations and separates …