Engineering Commons^™

Contact Resistance Evolution And Degradation Of Highly Cycled Micro-Contacts, Christopher L. Stilson

Theses and Dissertations

Reliable microelectromechanical systems (MEMS) switches are critical for developing high performance radio frequency circuits like phase shifters. Engineers have attempted to improve reliability and lifecycle performance using novel contact metals, unique mechanical designs and packaging. Various test fixtures including: MEMS devices, atomic force microscopes (AFM) and nanoindentors have been used to collect resistance and contact force data. AFM and nanoindentor test fixtures allow direct contact force measurements but are severely limited by low resonance sensors, and therefore low data collection rates. This thesis reports the contact resistance evolution results and fabrication of thin film micro-contacts dynamically tested up to 3kHz. …

Airborne Wireless Communication Modeling And Analysis With Matlab, Matthew J. Vincie

Theses and Dissertations

Over the past decade, there has been a dramatic increase in the use of unmanned aerial vehicles (UAV) for military, commercial, and private applications. Critical to maintaining control and a use for these systems is the development of wireless networking systems [1]. Computer simulation has increasingly become a key player in airborne networking developments though the accuracy and credibility of network simulations has become a topic of increasing scrutiny [2-5]. Much of the inaccuracies seen in simulation are due to inaccurate modeling of the physical layer of the communication system. This research develops a physical layer model that combines antenna …

Selectively Tuning A Buckled Si/Sio2 Membrane Mems Through Joule Heating Actuation And Mechanical Restriction, Kyle K. Ziegler

Theses and Dissertations

This research followed previous work and attempted to modify the spring in two ways. First, a Ti/Au meander resistor was deposited atop the membrane in an effort to actuate the membrane and change the spring constant. Secondly, a series of overhanging cantilevers were attached to the bulk substrate surrounding the membrane in an effort to constrain the membrane buckling deflection to the negative stiffness region. Membrane buckling was investigated through Finite Element analysis (FEA) and analytical equations. Deflections were measured using an interferometric microscope (IFM) and force/deflection measurements were captured using a unique measurement scheme. The results concluded that by …

Electrical Characterization Of Spherical Copper Oxide Memristive Array Sensors, James P. Orta

Theses and Dissertations

A new System Protection (SP) technology is explored by using electrical and mechanical interference-sensing devices that are implemented with granular memristive material. The granular materials consist of oxide-coated copper spheres with radii of about 700 µm that are placed in contact to produce thin oxide junctions which exhibit memristive behavior. Processes for etching, which compared acetic acid and nitric acid etches, and thermal oxidation at 100°C are performed and compared to produce copper spheres with a copper oxide layer over the sphere surface. Oxidized copper spheres are tested as sensor arrays by loading into a capillary tube in an aligned …

Fragment Capture Simulation For Manpads Test Arena Optimization, Michael J. Garee

Theses and Dissertations

The assessment of aircraft survivability against explosive munitions is an expensive undertaking. Test articles for both aircraft and weapon are scarce due to their high costs, leading to a limited supply of test data. The development of newer, hopefully more effective weaponry and protection measures continues despite the short supply of test data. Therefore, test organizations need to explore methods for increasing the quality of test results while looking for ways to decrease the associated costs. This research focuses on the Man-Portable Air-Defense System (MANPADS) as the weapon of choice and live- re arena testing as the experimental data source. …

Improving The Air Mobility Command's Air Refueler Route Building Capabilities, Tanya E. Kannon

Theses and Dissertations

We consider the problem of routing an aircraft (receiver) from a starting location to a target and back to an ending location while maintaining a fuel level above a predetermined level during all stages of the route and avoiding threat and no-fly zones. The receiver is routed to air refueling locations to refuel as required. The development of the network requires the processing of threat and no-fly zones to create the set of nodes that includes the bases (starting and end locations), the targets, and air refueling locations in addition to the restricted zone nodes. We develop a greedy heuristic …

A Heuristic Approach To The Theater Distribution Problem, Emily K. Power

Theses and Dissertations

Analysts at USTRANSCOM are tasked with providing vehicle mixtures that will support the distribution of requirements as provided in the form of TPFDD. An integer programming model exists to search for optimal solutions to these problems, but it is fairly time consuming, and produces only one of potentially several good quality solutions. This research constructs a number of heuristic approaches to solving the TDP. Two distinct shipping methods are examined and applied through both constructive and probabilistic vehicle assignment processes. Multistart metaheuristic approaches are designed and used in conjunction with the constructive and probabilistic approaches. Random TPFDDs of size 20, …

A Change Management Approach To Enhance Facility Maintenance Programs, Stanton P. Brown

Theses and Dissertations

A recent study assigned a grade of D+ on the nation's public infrastructure. Because of this poor asset condition, many organizations tend to respond to maintenance in a reactive mode; however, relying on corrective maintenance leads to increased maintenance costs due to unplanned downtime, increased labor costs, and inefficient use of personnel. To address this situation, asset management (AM) principles should be employed to transition organizations towards a proactive maintenance program. Unfortunately, it has been shown that two-thirds of the organizations failed to implement general change efforts. Therefore, an organizational change management framework should be followed to implement a change …

Interface Evaluation For Open System Architectures, Joshua A. Burger

Theses and Dissertations

This research develops a deterministic interface evaluation framework (IEF) in support of the principles identified in the Modular Open Systems Approach (MOSA). Interface evaluation in weapon system development requires a Decision Analysis (DA) method capable of handling a continuously growing alternative set and functioning with limited availability of senior decision makers. Value Focused Thinking (VFT) is selected as the best method for addressing the parameters of the framework. Inputs from the Medium Altitude Unmanned Aircraft System program office are used. An initial value threshold is established to guide open interface decisions, based on assessments of 15 historical decision scenarios. Open …

Exploring A Method To Quantitatively Measure Design Flexibility Early In The Defense Acquisition Life Cycle, Joseph S. Kim

Theses and Dissertations

The purpose of this research was to demonstrate a methodology using an Epoch-Era Analysis to quantify and estimate the value of design flexibility early in the Department of Defense's (DOD) acquisition life cycle. This method was implemented using a possible replacement to the Air Force's fighter-trainer aircraft as a baseline and a set of future requirements that would change the baseline. An existing Cost Estimating Relationship tool was utilized in conjunction with a decision tree modeling approach to accommodate uncertain future needs. Sensitivity analysis was performed to identify model parameters with dominant effects on the recommended design strategies. The results …

Design Considerations For A Water Treatment System Utilizing Ultra-Violet Light Emitting Diodes, Michael J. Spencer

Theses and Dissertations

UV LED technology is in its infancy and research as it applies to UV water treatment is required to advance knowledge for practical application. This thesis focused on two subjects. First, the design, fabrication, and operation of a water treatment reaction system utilizing Ultra-Violet (UV) Light Emitting Diodes (LEDs). Second, the measurement of UV LED output angle in water which is necessary to support future reactor designs. Several characteristics of the LED-water interface were revealed which impacted the effectiveness of the vessel including; UV dose requirements, LED wavelength, photon dispersion geometry, LED placement, optical efficiency, vessel material, and electronic control …

Improving The Enterprise Requirements And Acquisition Model's Development Test And Evaluation Process Fidelity, Jason W. Sutherlin

Theses and Dissertations

Shrinking budgets and dynamic military conflicts have driven Department of Defense (DoD) leadership to reform how the military acquires weapon systems with the goal of decreasing program schedules and costs, while maximizing performance. With fifty years of reform, the DoD has been unable to adequately control program schedule objectives. Previous research attempted to support acquisition reforms through modeling and simulation. The Enterprise Requirements and Acquisition Model (ERAM) captures a program's progression through the Defense Acquisition Management System to gain insight into significant delays that impact program schedule and probability of completion. A past unexpected result included the insignificant impact that …

An Analysis Of Eye Movements With Helmet Mounted Displays, Kalyn A. Tung

Theses and Dissertations

Helmet or Head-Mounted Displays (HMD) applications have expanded to include a range from advanced military cockpits to consumer glasses. However, users have documented loss of legibility while undergoing vibration. Recent research indicates that undesirable eye movement is related to the vibration frequency a user experiences. In vibrating environments, two competing eye reflexes likely contribute to eye movements. The Vestibulo-ocular Reflex responds to motion sensed in the otoliths while the pursuit reflex is driven by the visual system to maintain the desired image on the fovea. This study attempts to isolate undesirable eye motions that occur while using a HMD by …

Feasibilty Of Very Large Sparse Aperture Depolyable Antennas, Jason C. Heller

Theses and Dissertations

The objective of this research is to explore the technical soundness of a very large, cross-shaped, parabolic, sparse aperture antenna extending 75 m from the bus. Specifically, describing the environment of the satellite, the effect of fabrication error on the structure and the remaining error budget for the system. The methodology involves creation of an ideal truss structure, to which all others are compared. A uniform distribution of proportional errors up to 1e-5 is introduced into the truss members' lengths and the models are subjected to a static Finite Element Analysis. A solution for the surface normal error is addressed …

The Use Of An Ultra-Compact Combustor As An Inter-Turbine Burner For Improved Engine Performance, Jose L. Miranda

Theses and Dissertations

An Inter-Turbine Burner (ITB) represents a novel mechanism for generating additional work from a gas turbine engine in applications where an afterburner would typically be used. An ITB can achieve higher thermal efficiencies over a typical afterburner while also generating shaft work versus only additional thrust. In an effort to investigate the potential applications for the ITB, a numerical engine cycle comparison was made between the ITB cycle and a conventional afterburning cycle using the Numerical Propulsion System Simulation (NPSS). In the case of thrust augmentation, the ITB model outperformed the afterburning model when Thrust Specific Fuel Consumption (TSFC) is …

Optimal Uav Path Planning For Tracking A Moving Ground Vehicle With A Gimbaled Camera, Riley A. Livermore

Theses and Dissertations

This research develops a path planning algorithm that autonomously controls a UAV to provide convoy overwatch. The optimization algorithm determines the best path to y through developing a cost function that minimizes the control effort of the UAV and the deviation from a desired slant range. A heuristic-based algorithm was developed and implemented on the autopilot to approximate the optimal solution. In flight test, the UAV successfully tracked a moving ground vehicle by continually placing the UAV's loiter point directly above the ground vehicle's current location. This method was called the \follow-me mode and provided the baseline for real-world UAV …

Comm-Using Decibels - Loose Slides, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Comm-Using Decibles - Loose Slides" from March 13. 2014.

Environmentally Friendly And Sustainable Stream Stability In The Vicinity Of Bridges, Evan David Cope

Theses and Dissertations

This report was sponsored by the Utah Department of Transportation (UDOT) to determine if stream restoration structures could be used as scour countermeasures near state highways and bridges. Scour countermeasures that are effective in preventing erosion exist but that are not so friendly for aquatic organisms. UDOT is interested in finding a countermeasure that is both effective in preventing erosion while not harming aquatic organisms. Stream restoration structures are friendly for aquatic organisms but are prone to failure when flows exceed the design levels. David Rosgen has developed restoration structures that are friendly for aquatic organisms and that have provided …

Atlas-Guided Volumetric Diffuse Optical Tomography Enhanced By Generalized Linear Model Analysis To Image Risk Decision-Making Responses In Young Adults, Zi-Jing Lin, Lin Li, Mary Cazzell, Hanli Liu

Bioengineering Faculty Publications - Archive

No abstract provided.

Post-Fracture Capacity Of Railroad Flat Car Bridges, Teresa L. Washeleski

Purdue Road School

Railroad flatcars (RRFCs) are a convenient option to replace existing deteriorating bridge structures on low-volume roads. They are typically used as the bridge superstructure by placing two or more flatcars side-by-side to achieve the desired bridge width. Utilizing RRFCs as a bridge allows for rapid construction and greater cost savings compared to traditional practices. These benefits make them an attractive solution for rural communities in Indiana, as well as other states.

Uncertainty remains about the response under higher loads than could be easily achieved in the field and the level of redundancy of railroad flatcar bridges. Using RRFCs as bridges …

Ada Focused Construction Inspection, Erik Seef, Eryn Fletcher

Purdue Road School

This presentation will introduce inspection guidelines for field staff to implement in inspecting projects with pedestrian facilities, including curb ramps and pedestrian signals. Review of new INDOT curb standards and requirements for accessible pedestrian signals will be included. These recent changes in standards will impact projects and thus it is imperative to advise field staff of what they should be looking for with regard to width and slopes on pedestrian access routes and pedestrian push buttons. Several issues have been noted in the field, including excessive cross slope and running slope, installation of fingertip-actuated push buttons, and substandard level landings …

Road Safety Audits, Henry Brown

Purdue Road School

A Road Safety Audit (RSA) is a formal review of an existing or proposed road segment or intersection by an independent, multi-disciplinary team. The purpose of an RSA is to identify safety concerns and suggest possible countermeasures to the project owner. There are several benefits to conducting RSAs, including increased awareness of safety and a reduction in the number of crashes. The RSA process includes 8 steps during which the RSA team develops a list of findings and presents them to the project owner for consideration. The RSA process for an existing facility includes a field review during which the …

I-65 South Split Continuously Reinforced Concrete Pavement, Tommy E. Nantung

Purdue Road School

Continuously reinforced concrete pavement (CRCP) is constructed with reinforcing steel placed in along the entire length of the pavement. CRCP forms tight transverse cracks to evenly transfer loads without the need of contraction joints. The result is a continuous, smooth-riding pavement surface capable of accommodating heavy traffic loads in a severe environmental condition. First constructed in Indiana more than 75 years ago on US-50, CRCP became popular with the construction of the Interstate Highway system in the 1960s and 1970s. Many sections of interstate and non-interstate highways constructed at that time are still in service today, having outperformed their original …

2014 Road School, Kevin M. Hetrick

Purdue Road School

At the 2014 Road School, this presentation focused on the proposed sliding of the Milton-Madison Bridge, a 15000 ton truss superstructure intended to move laterally 55 feet from a temporary location onto permanent piers. The project was a joint procurement between INDOT and KYTC, with a Design/Build team consisting of Walsh Construction, Buckland and Taylor, and Burgess and Niple performing the slide. The presentation was in early March, with the slide scheduled for later in the month. The slide will be the largest of its kind.

Most Common Errors For Ada Ramp Construction, Stephen G. Metzer Aicp, Pws

Purdue Road School

Curb ramps are essential for persons with disabilities to traverse pedestrian facilities, allowing them to get from street level to the sidewalk. Errors that occur during the construction of curb ramps can result in ramps that are non-compliant with the Americans with Disabilities Act (ADA) guidelines. This presentation will include examples of common sidewalk construction errors and offer ways that project engineers can assess existing ramps to identify cases where additional design assistance may be required.

Drilled Shaft Design & Construction-Integrity Testing Issues, Mir A. Zaheer, David Latka

Purdue Road School

This presentation will provide an overview of the design and construction of drilled shafts in Indiana, including construction monitoring issue, discussion of CSL, PIT and TIP testing, and comparisons with cores taken.

Post-Failure Capacity Of Built-Up Steel Members, Matthew H. Hebdon

Purdue Road School

Mechanically fastened built-up steel members have long been known to possess internal member redundancy and, as a result, multiple load paths which can be exploited to increase their functional life. Internal redundancy provides the ability to resist total member failure in the event of a fracture of an individual component. However, there is little experimental data in the literature regarding post-fracture capacity in terms of strength and subsequent fatigue life. The experimental study currently underway will provide needed information on parameters that affect the ability of built- up members to arrest a fracture as well as the available remaining fatigue …

Ada Prowag Status And Common Issues/Solutions, Stephen G. Metzer Aicp, Pws

Purdue Road School

The Proposed Accessibility Guidelines for Pedestrian facilities in the Public Right-of-Way (aka PROWAG), dated July 26, 2011, went through an extensive public comment period that ended in early 2012. The Access Board anticipates issuing final guidance that will be the enforceable standard for facilities in the public ROW. This presentation will provide the latest status of the guidelines and present common problems and creative solutions.

Influence Of Reduction Promoters On Stability Of Cobalt/Γ-Alumina Fischer-Tropsch Synthesis Catalysts, Gary Jacobs, Wenping Ma, Burtron H. Davis

Center for Applied Energy Research Faculty and Staff Publications

This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the nanoscale to other cobalt particles on the surface. Recent efforts have shown that when promoters are used to facilitate the reduction of small crystallites with the aim of increasing surface Co⁰ site densities (e.g., in research catalysts), ultra-small crystallites (e.g., < 2–4.4 nm) formed are more susceptible to oxidation at high conversion relative to larger ones. The choice of promoter is important, as certain metals (e.g., Au) that promote cobalt oxide reduction can separate from cobalt during oxidation-reduction (regeneration) cycles. Finally, some elements have been identified to promote reduction but either poison the surface of Co⁰ (e.g., Cu), or produce excessive light gas selectivity (e.g., Cu and Pd, or Au at …

A Cavity-Backed Spiral Slot Antenna With Wide Axial Ratio Beamwidth For Gps System, Xiulong Bao, Max Ammann

Articles

A monofilar spiral slot antenna with a cavity-backed reflector is described. presented, which can achieve the performance of the wide Axial Ratio beamwave for Global Positioning System GPS system. It comprises an arrangement of a single printed spiral slots fed by a 50 Ω microstrip line. By using cavity-backed covering the slot structure, a wide axial ratio beamwidth performance is achieved in the GPS L1 frequency. The angle with less than 3 dB axial ratio at 1.575 GHz in the YoZ plane is about 215 degree. The measured results show that the HPWB beamwidths at 1.575 GHz are 100 degree …