Engineering Commons^™

Integration Of Fault Tolerance And Hardware Redundancy Techniques Into The Design Of Mobile Platforms, Miguel Angel Espina

FIU Electronic Theses and Dissertations

This work addresses the development of a fault-tolerant mobile platform. Fault-tolerant mechanical system design is an emerging technology that attempts to build highly reliable systems by incorporating hardware and software architectures. For this purpose, previous work in fault-tolerant were reviewed. Alternate architectures were evaluated to maximize the fault tolerance capabilities of the driving and steering systems of a mobile platform.

The literature review showed that most of the research work on fault tolerance has been done in the area of kinematics and control systems of robotic arms. Therefore, hardware redundancy and fault tolerance in mobile robots is an area to …

Sorption Measurements And Behavior Of Monosodium Methanearsonate And Arsenic (+5) In Aqueous Suspensions Of Floridian Soil Fractions, George William Di Carlo

FIU Electronic Theses and Dissertations

Adsorption experiments using both monosodium methanearsonate (MSMA) and its inorganic degradation by-product species As(+5), as sodium arsenate Na₂AsO₄, were conducted to evaluate the sorptivity of these constituents to various fractions of soil samples taken from the West Palm Beach Country Club. Adsorption data were analyzed with common isotherm equations (i.e., Linear, Freundlich, Langmuir) to determine K_d for each arsenic (As) species/soil fraction. Simulations using a one-dimensional pesticide transport model, PRZM 2.0, were completed to evaluate possible dissolved concentrations of arsenic at the water table interface under 8 different application scenarios for the soil profile found …

Low Vision, Stimulus Encoding And Information Processing: A Characterization Of Performance Of Partially Sighted Users On Computer-Based Tasks, Max A. Dixon

FIU Electronic Theses and Dissertations

This study focuses on the characterization of partially sighted users' performance within a graphical user interface environment. Participants, ranging in visual abilities from fully sighted (FSU) with no visual impairments to partially sighted (PSU) with limited visual abilities, participated in computer-based search and select tasks. It is shown that visual search strategies employed by both PSU and FSU within a graphical user interface can be described by Steinberg's (1969) Additive Factor Model. In addition, selection strategies, measured by mouse movement times, are linearly related and highly correlated to the Index of Difficulty as explained by Fitts' Law. This is the …

Yttria Stabilized Zirconia Buffered Silicon: Substrates For Ybco Microwave Applications, Philip D. Brown

FIU Electronic Theses and Dissertations

The use Yttria-Stabilized Zirconia (YSZ) as a buffer layer for YBa₂Cu₃O_7-x (YBCO) thin films on (100) silicon (Si) substrates is investigated. YSZ was grown using on-axis pulsed D.C. (PDC) and R.F. magnetron sputtering from a 99.9% pure YSZ target [(Y₂O₃)_0.08(ZrO₂)_0.92]. Sputtering was carried out in Argon/Oxygen atmosphere at total pressures ranging from 6 to 320 mTorr containing 0.1 to 10% Oxygen. Substrate temperatures were varied from 300° C to 900° C. (111), (100) and mixed (100) and (111) oriented YSZ films were produced …

Crack Tip Stress Study For Elastic-Perfectly Plastic Materials With Some Applications, Ivan Enrique Esparragoza

FIU Electronic Theses and Dissertations

The problems of plasticity and non-linear fracture mechanics have been generally recognized as the most difficult problems of solid mechanics. The present dissertation is devoted to some problems on the intersection of both plasticity and non-linear fracture mechanics. The crack tip is responsible for the crack growth and therefore is the focus of fracture science. The problem of crack tip has been studied by an army of outstanding scholars and engineers in this century, but has not, as yet, been solved for many important practical situations. The aim of this investigation is to provide an analytical solution to the problem …

Adaptive Segmenting Of Non-Stationary Signals, Christopher Albin Edmonds

FIU Electronic Theses and Dissertations

Many data compression techniques rely on the low entropy and/or the large degree of autocorrelation exhibited by stationary signals. In non-stationary signals, however, these characteristics are not constant, resulting in reduced data compression efficiency. An adaptive scheme is developed that divides non-stationary signals into smaller locally stationary segments, thereby improving overall efficiency. Two principal issues arise in implementing this procedure. The first is practical; an exhaustive search of all possible segmentations is in general computationally prohibitive. The concept of dynamic programming is applied to reduce the expense of such a search. The second involves choosing a cost function that is …

Degradation Of Azo Dyes In Aqueous Solution By H2o2/Fe2+ And H2o2/Fe, Sangeeta Dhulashia

FIU Electronic Theses and Dissertations

An advanced oxidation process, which uses Fenton's Reagent (H₂O₂/Fe²⁺), is studied in the destruction of three different classes of azo dyes. The optimal pH and stochiometry for H₂0₂ and Fe²⁺ in the oxidation of the azo dyes were investigated; an experimental optimal ratio was also compared to a theoretical optimal ratio of H₂0₂ to Fe²⁺. The optimal oxidation of monoazo and disazo dyes is at pH 3 and pH 4, respectively. The optimal ratio for monoazo and disazo dyes ranged from 1 to 10. The …

An Experimental Study Of Micro-End-Milling Operations, Tug Tacku Arkan

FIU Electronic Theses and Dissertations

Cutting tools less than 2mm diameter can be considered as micro-tool. Microtools are used in variety of applications where precision and accuracy are indispensable. In micro-machining operations, a small amount of material is removed and very small cutting forces are created. The small cross sectional area of the micro-tools drastically reduces their strength and makes their useful life short and unpredictable; so cutting parameters should be selected carefully to avoid premature tool breakage. The main objective of this study is to develop new techniques to select the optimal cutting conditions with minimum number of experiments and to evaluate the tool …