Engineering Commons^™

High Cycle Fatigue Of Aa6082 And Aa6063 Aluminum Extrusions , Nicholas E. Nanninga

Dissertations, Master's Theses and Master's Reports - Open

The high cycle fatigue behavior of hollow extruded AA6082 and AA6063 aluminum extrusions has been studied. Hollow extruded aluminum profiles can be processed into intricate shapes, and may be suitable replacements for fatigue critical automotive applications requiring reduced weight. There are several features inherent in hollow aluminum extrusions, such as seam welds, charge welds, microstructural variations and die lines. The effects of such extrusion variables on high cycle fatigue properties were studied by taking specimens from an actual car bumper extrusion. It appears that extrusion die lines create large anisotropy differences in fatigue properties, while welds themselves have little effect …

Fabrication And Characterization Of Room Temperature Operating Single Electron Transistors Using Focused Ion Beam Technologies, Prasanjit Santosh Karre

Dissertations, Master's Theses and Master's Reports - Open

The single electron transistor (SET) is a Coulomb blockade device, whose operation is based on the controlled manipulation of individual electrons. Single electron transistors show immense potential to be used in future ultra lowpower devices, high density memory and also in high precision electrometry. Most SET devices operate at cryogenic temperatures, because the charging energy is much smaller than the thermal oscillations. The room temperature operation of these devices is possible with sub- 10nm nano-islands due to the inverse dependance of charging energy on the radius of the conducting nano-island. The fabrication of sub-10nm features with existing lithographic techniques is …

Comparison Of Common Dredging Equipment Air Emissions , Mark J. Anderson P.E.

Dissertations, Master's Theses and Master's Reports - Open

The purpose of this study is to provide a procedure to include emissions to the atmosphere resulting from the combustion of diesel fuel during dredging operations into the decision-making process of dredging equipment selection. The proposed procedure is demonstrated for typical dredging methods and data from the Illinois Waterway as performed by the U.S. Army Corps of Engineers, Rock Island District. The equipment included in this study is a 16-inch cutterhead pipeline dredge and a mechanical bucket dredge used during the 2005 dredging season on the Illinois Waterway.

Considerable effort has been put forth to identify and reduce environmental impacts …

Photolithography Based Patterning Of Bacteriorhodopsin Films, Christopher M. Anton

Dissertations, Master's Theses and Master's Reports - Open

The patterning of photoactive purple membrane (PM) films onto electronic substrates to create a biologically based light detection device was investigated. This research is part of a larger collaborative effort to develop a miniaturized toxin detection platform. This platform will utilize PM films containing the photoactive protein bacteriorhodopsin to convert light energy to electrical energy.

Following an effort to pattern PM films using focused ion beam machining, the photolithography based bacteriorhodopsin patterning technique (PBBPT) was developed. This technique utilizes conventional photolithography techniques to pattern oriented PM films onto flat substrates. After the basic patterning process was developed, studies were conducted …

Bislug Flow In Circular And Noncircular Channels And The Role Of Interface Stretching On Energy Dissipation, Joseph E. Hernandez

Dissertations, Master's Theses and Master's Reports - Open

The area of microfluidics has increased in popularity with such fields as MEMS, microreactors, microscaleheat exchangers, etc. A comprehensive understanding of dissipation mechanisms for fluid flow in microchannels is required to accurately predict the behavior in these small systems. Tests were performed using a constant pressure potential created by two immiscible fluids juxtaposed in a microchannel. This study focused on the flow and dissipation mechanisms in round and square microchannels. There are four major dissipation mechanisms in slug flow; wall shear, dissipation at the contact line, menisci interaction and the stretching of the interface. A force balance between the internal …

Development Of A Direct Evaporation Bismuth Hall Thruster, Dean Richard Massey

Dissertations, Master's Theses and Master's Reports - Open

Hall thrusters have been under active development around the world since the 1960’s. Thrusters using traditional propellants such as xenon have been flown on a variety of satellite orbit raising and maintenance missions with an excellent record. To expand the mission envelope, it is necessary to lower the specific impulse of the thrusters but xenon and krypton are poor performers at specific impulses below 1,200 seconds.

To enhance low specific impulse performance, this dissertation examines the development of a Hall-effect thruster which uses bismuth as a propellant. Bismuth, the heaviest non-radioactive element, holds many advantages over noble gas propellants from …

Quantum Dot / Optical Protein Bio-Nano Hybrid System Biosensing, Mark H. Griep

Dissertations, Master's Theses and Master's Reports - Open

The integration of novel nanomaterials with highly-functional biological molecules has advanced multiple fields including electronics, sensing, imaging, and energy harvesting. This work focuses on the creation of a new type of bio-nano hybrid substrate for military biosensing applications. Specifically it is shown that the nano-scale interactions of the optical protein bacteriorhodopsin and colloidal semiconductor quantum dots can be utilized as a generic sensing substrate.

This work spans from the basic creation of the protein to its application in a novel biosensing system. The functionality of this sensor design originates from the unique interactions between the quantum dot and bacteriorhodopsin molecule …

Multiscale Constitutive Modeling Of Polymer Materials, Pavan Kumar Valavala

Dissertations, Master's Theses and Master's Reports - Open

Materials are inherently multi-scale in nature consisting of distinct characteristics at various length scales from atoms to bulk material. There are no widely accepted predictive multi-scale modeling techniques that span from atomic level to bulk relating the effects of the structure at the nanometer (10^-9 meter) on macro-scale properties. Traditional engineering deals with treating matter as continuous with no internal structure. In contrast to engineers, physicists have dealt with matter in its discrete structure at small length scales to understand fundamental behavior of materials. Multiscale modeling is of great scientific and technical importance as it can aid in designing …

Adaptive Control Of Sinusoidal Brushless Dc Motor Actuators, Liangtao Zhu

Dissertations, Master's Theses and Master's Reports - Open

Electrical Power Assisted Steering system (EPAS) will likely be used on future automotive power steering systems. The sinusoidal brushless DC (BLDC) motor has been identified as one of the most suitable actuators for the EPAS application. Motor characteristic variations, which can be indicated by variations of the motor parameters such as the coil resistance and the torque constant, directly impart inaccuracies in the control scheme based on the nominal values of parameters and thus the whole system performance suffers. The motor controller must address the time-varying motor characteristics problem and maintain the performance in its long service life.

In this …

Performance Evaluation Of Vip Latrines In The Upper West Region Of Ghana , James W. Dumpert

Dissertations, Master's Theses and Master's Reports - Open

The prevalence of Ventilated Improved Pit (VIP) latrines in Ghana suggests that the design must have a high user acceptance. The two key factors attributed to user acceptance of a VIP latrine over an alternative latrine design, such as the basic pit latrine, are its ability to remove foul odors and maintain low fly populations; both of which are a direct result of an adequate ventilation flow rate.

Adequate ventilation for odorless conditions in a VIP latrine has been defined by the United Nations Development Program (UNDP) and the World Bank, as an air flow rate equivalent to 6 air …

The Effect Of Demand, Tank Parameters, And Pumping Stations On Energy Use In Municipal Drinking Water Distribution Systems, Santosh Raj Ghimire

Dissertations, Master's Theses and Master's Reports - Open

Two of the indicators of the UN Millennium Development Goals ensuring environmental sustainability are energy use and per capita carbon dioxide emissions. The increasing urbanization and increasing world population may require increased energy use in order to transport enough safe drinking water to communities. In addition, the increase in water use would result in increased energy consumption, thereby resulting in increased green-house gas emissions that promote global climate change. The study of multiple Municipal Drinking Water Distribution Systems (MDWDSs) that relates various MDWDS aspects--system components and properties--to energy use is strongly desirable. The understanding of the relationship between system aspects …

Planning And Adaptation Measures For Urban Slum Communities In West Africa : Stochastic Rainfall Modeling Applied To Domestic Rainwater Harvesting And Climate Change Adaptation, Joshua R. Cowden

Dissertations, Master's Theses and Master's Reports - Open

Over half of the world’s population is living in urban settlements, and most urban growth is occurring in developing countries. These countries’ economies are often unable to accommodate these rural-urban immigrations, resulting in millions of people settling in insecure communities known as urban slums. Current efforts to prevent urban slums include UN-HABITAT strategies to upgrade slums and stimulate urban/regional development. Urban metabolism analysis, which studies material and energy flows/stocks through urban processes, help decision-makers better understand their urban system. Nine lessons from past urban metabolism studies are presented to assist in finding answers on how to best solve urban slum …