Engineering Commons^™

Rf Sputter Optimization Of Germanium Sulfide (Ges2) Thin Films, Steven Livers

College of Engineering Poster Presentations

Radio frequency sputter deposition of germanium sulfide thin films can be optimized for surface thickness homogeneity and surface roughness. Optimizing these two components are the first steps of producing memory devices that use the film as a solid electrolyte. The best films were produced using a sputter power of 16 Watts and a pressure of 0.2 mbar. Using these settings a deposition rate of 3.7 nm/min was recorded and the films had a minimum RMS surface roughness of 0.4550 nm.

Minimization Of Surface Impurities In Anodized Aluminum, Logan Ward, Steven Livers, Amber Huddleston

College of Engineering Poster Presentations

Anodized aluminum is commonly used to create wear-resistant parts for process tools used in the semiconductor industry. Sinc microchips require high purity manufacturing environments[1], surface impurities on tooling needs to be minimized.

It has been determined that anodized aluminum parts are one source of contamination. This project investigates the source of trace elements in anodized aluminum 6061 parts and ways to reduce them.

Hop Funnel And Field Emitter Array Interaction, Tyler Rowe

College of Engineering Poster Presentations

Investigate the use of hop funnels with field emitter arrays (FEAs) as a method to improve FEA performance for use in various microwave vacuum electron devices (MVEDs).

Digital Control Of Parallel-Connected Dc-Dc Converters, Taufik, Daniel Forbes, Dale Dolan, Ratna Ika Putri

Electrical Engineering

This paper presents a digitally-controlled paralleled DC-DC converter. The main objective of the digital control is to achieve load sharing while operating at close to peak efficiency over an extremely wide load range. Results from computer simulations using Simulink show the digital control could indeed accomplish the objectives, but the improvements over a single converter depend on the original efficiency characteristics of the converters. An application for a high-power electric vehicle charger utilizing this converter setup is considered.

A Prototyping Hardware Platform For ∆Σ Adcs, Abbas Alahmed, Mohammed Alhajji, Zacharias Arnos, Vishal Saxena

College of Engineering Poster Presentations

The project involves development of a generic test-bed for prototyping and characterizing Delta-Sigma Analog-to-Digital Converters (ADCs). The ADCs are designed at the Analog Mixed Signal IC (AMS) Laboratory at Boise State. This is a high-speed evaluation board that can be connected into an FPGA board which assists in controlling the ADC chip and assists in capturing blocks of digital data.

Minidoka Memorial Hospital Expansion, Bryanne Calkins, Mike Dupras, William Thornton, Brett Feichtinger, Corinne Haase, Ena Beganovic, Scott Moreno

College of Engineering Poster Presentations

The Minidoka Memorial Hospital is the main hospital serving Minidoka County. Due to an increase in farming and traffic accidents, the emergency facilities are no longer adequate and require expansion.

Camera Imaging System, Wayne Kreimeyer, Adrian Rothenbühler, Anita Poudel, Elisa Barney Smith

College of Engineering Poster Presentations

• Magnetic shape memory alloys are functional materials which can remember their shape
•  Currently, twin boundaries as a function of magnetic field angle can not be measured
•  Information about shape changes of different parts of the sample will increase the understanding of deformation mechanisms

Effects Of Electromagnetic Stimulation On Soil’S Hydraulic Conductivity, Jonathan Rocha, Arvin Farid, Jim Browning

College of Engineering Poster Presentations

Our research involves the identification of the different effects that electromagnetic (EM) stimulation has on varying soil properties; properties such as hydraulic conductivity. This work could prove to be of importance in furthering our understanding of the effects of EM stimulation with regard to the hydraulic conductivity of soil. A positive correlation between EM stimulation and an increase in hydraulic conductivity could have broad applications for environmental contaminant mitigation in soils and for various geotechnical construction applications such as minimizing soil setup during pile driving operations. EM waves can be used to enhance soil and groundwater remediation in a way …

Bifurcation-Based Mass Sensing Using Piezoelectrically-Actuated Microcantilevers, Vijay Kumar, J. William Boley, Yushi Yang, Hendrik Ekowaluyo, Jacob K. Miller, George T.C. Chiu, Jeff F. Rhoads

Birck and NCN Publications

In conventional implementations, resonant chemical and biological sensors exploit chemomechanically-induced frequency shifts, which occur in linear systems, for analyte detection. In this letter, an alternative sensing approach, based upon dynamic transitions across saddle-node bifurcations is investigated. This technique not only has the potential to render improved sensor metrics but also to eliminate frequency tracking components from final device implementations. The present work details proof-of-concept experiments on bifurcation-based sensing, which were conducted using selectively functionalized, piezoelectrically-actuated microcantilevers. Preliminary results reveal the proposed sensing technique to be a viable alternative to existing resonant sensing methods. (C) 2011 American Institute of Physics. [doi:10.1063/1.3574920]

Enhanced Ulf Radiation Observed By Demeter Two Months Around The Strong 2010 Haiti Earthquake, M. A. Athanasiou, Georgios C. Anagnostopoulos, A. C. Iliopoulos, G. P. Pavlos, C. N. David

Electrical Engineering and Computer Science Faculty Publications

In this paper we study the energy of ULF electromagnetic waves that were recorded by the satellite DEMETER, during its passing over Haiti before and after a destructive earthquake. This earthquake occurred on 12 January 2010, at geographic Latitude 18.46° and Longitude 287.47°, with Magnitude 7.0 R. Specifically, we are focusing on the variations of energy of Ez-electric field component concerning a time period of 100 days before and 50 days after the strong earthquake. In order to study these variations, we have developed a novel method that can be divided in two stages: first we filter the signal, keeping …

Gas Embolic Factors In Cardiovascular Health, Eric L. Cutler

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Gas emboli are a clinical issue often encountered in the space exploration, marine construction, and medical fields.  Individuals involved with these disciplines will often have asympomatic gas emboli circulating throughout their bodies on a regular basis.  A study into the impact of chronic asymptomatic gas emboli on the risk of atherosclerosis in humans is thus presented.  This research utilized a custom built cardiovascular flow simulator and accompanying data acquisition system to experimentally determine the influence of gas emboli under varied circumstances on the mean wall shear stress of a tube in-vitro.  A directly inverse relationship between gas embolus presence in …

Direct Numerical Simulation Of Hypersonic Turbulent Boundary Layers. Part 3. Effect Of Mach Number, L. (Lian) Duan, I. Beekman, M. P. Martín

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, we perform direct numerical simulations (DNS) of turbulent boundary layers with nominal free-stream Mach number ranging from 0.3 to 12. The main objective is to assess the scaling's with respect to the mean and turbulence behaviors as well as the possible breakdown of the weak compressibility hypothesis for turbulent boundary layers at high Mach numbers (M > 5). We find that many of the scaling relations, such as the van Driest transformation for mean velocity, Walz's relation, Morkovin's scaling and the strong Reynolds analogy, which are derived based on the weak compressibility hypothesis, remain valid for the range …

Reliability Testing Of Algan/Gan Hemts Under Multiple Stressors, Bradley D. Christiansen, Ronald A. Coutu Jr., Eric R. Heller, Brian S. Poling, Glen D. Via, Ramakrishna Vetury, Jeffrey B. Shealy

Electrical and Computer Engineering Faculty Research and Publications

We performed an experiment on AlGaN/GaN HEMTs with high voltage and high power as stressors. We found that devices tested under high power generally degraded more than those tested under high voltage. In particular, the high-voltage-tested devices did not degrade significantly as suggested by some papers in the literature. The same papers in the literature also suggest that high voltages cause cracks and pits. However, the high-voltage-tested devices in this study do not exhibit cracks or pits in TEM images, while the high-power-tested devices exhibit pits.

Quantitative Reappraisal Of The Helmholtz-Guyton Resonance Theory Of Frequency Tuning In The Cochlea, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

To explore the fundamental biomechanics of sound frequency transduction in the cochlea, a two-dimensional analytical model of the basilar membrane was constructed from first principles. Quantitative analysis showed that axial forces along the membrane are negligible, condensing the problem to a set of ordered one-dimensional models in the radial dimension, for which all parameters can be specified from experimental data. Solutions of the radial models for asymmetrical boundary conditions produce realistic deformation patterns. The resulting second-order differential equations, based on the original concepts of Helmholtz and Guyton, and including viscoelastic restoring forces, predict a frequency map and amplitudes of deflections …

The Composition And Distribution Of Coal-Ash Deposits Under Reducing And Oxidizing Conditions From A Suite Of Eight Coals, David R. Brunner

Theses and Dissertations

Eighteen elements, including: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were measured using a scanning electron microscope with energy dispersive spectroscopy from deposits. The deposits were collected by burning eight different coals in a 160 kWth, staged, down-fired, swirl-stabilized combustor. Both up-stream and down-stream deposits from an oxidizing region (equivalence ratio 0.86) and reducing region (equivalence ratio 1.15) were collected. Within the deposits, the particle size and morphology were studied. The average particle cross-sectional area from the up-stream deposits ranged from 10 - 75 µm2 and had a …

Surface Geometry And Heat Flux Effect On Thin Wire Nucleate Pool Boiling Of Subcooled Water In Mictrogravity, Troy Munro, Heng Ban

Presentations

No abstract provided.

Wright State University Celebration Of Research, Scholarship And Creative Activities Book Of Abstracts Friday, April 8, 2011, Wright State University Office Of Undergraduate Research And Stemm Activities

Celebration of Undergraduate & Graduate Research, Scholarship, and Creative Activities Materials

The student abstract booklet is a compilation of abstracts from students' oral and poster presentations at Wright State University's second annual Celebration of Research, Scholarship and Creative Activities on April 8, 2011.

Multi-Resolution Obstacle Mapping With Rapidly-Exploring Random Tree Path Planning For Unmanned Air Vehicles, Brett Wayne Millar

Theses and Dissertations

Unmanned air vehicles (UAVs) have become an important area of research. UAVs are used in many environments which may have previously unknown obstacles or sources of danger. This research addresses the problem of obstacle mapping and path planning while the UAV is in flight. Online obstacle mapping is achieved through the use of a multi-resolution map. As sensor information is received, a quadtree is built up to hold the information based upon the uncertainty associated with the measurement. Once a quadtree map of obstacles is built up, we desire online path re-planning to occur as quickly as possible. We introduce …

Terrain Analysis Using Digital Elevation Models, David G. Tarboton, Daniel W. Watson, Rob Wallace, Kimberly A. T. Schreuders, Jeremy Neff

Civil and Environmental Engineering Faculty Publications

No abstract provided.

The Cuahsi Community Hydrologic Information System, David G. Tarboton, David R. Maidment, Ilya Zaslavsky, Jon Goodall, Daniel Ames, Jeffery S. Horsburgh, Kimberly A. T. Schreuders

Civil and Environmental Engineering Faculty Publications

No abstract provided.

Accelerating Finite State Projection Through General Purpose Graphics Processing, Thomas Trimeloni

Theses and Dissertations

The finite state projection algorithm provides modelers a new way of directly solving the chemical master equation. The algorithm utilizes the matrix exponential function, and so the algorithm’s performance suffers when it is applied to large problems. Other work has been done to reduce the size of the exponentiation through mathematical simplifications, but efficiently exponentiating a large matrix has not been explored. This work explores implementing the finite state projection algorithm on several different high-performance computing platforms as a means of efficiently calculating the matrix exponential function for large systems. This work finds that general purpose graphics processing can accelerate …

Development Of An Integrated Project-Based Course: A Jobsite Management Class Case Study, Philip L. Barlow

Construction Management

At universities offering professional degrees, such as construction management, some programs are moving towards and exploring alternative delivery methods for achieving the curriculum’s goals and objectives. This paper describes a curriculum integrated course founded in a project-based learning environment applied to a jobsite construction management undergraduate course being taught at a major university. A course overview describing the various delivery methods used (such as lectures, reading assignments, supplemental materials, guest lecturers, lab assignments, technology, and a jobsite visit) is presented. The benefits of course integration in a construction management undergraduate curriculum are emphasized and more fully explained. The unique student …

Grain Refinement Vs. Crystallographic Texture: Mechanical Anisotropy In A Magnesium Alloy, D. C. Foley, M. Al-Maharbi, K. T. Hartwig, I. Karaman, L. J. Kecskes, S. N. Mathaudhu

United States Army: Publications

A magnesium alloy was subjected to severe plastic deformation via an unconventional equal channel angular extrusion route at decreasing temperatures. This method facilitates incremental grain refinement and enhances formability by activating dynamic recrystallization in the initial steps and suppressing deformation twinning. Compression experiments in three orthogonal directions demonstrated high strength levels in the processed sample, up to 350 MPa in yield and 500 MPa in ultimate strengths. Notable flow stress anisotropy is correlated with the processing texture and microstructure.

Capture And Sequestration Of Carbon Dioxide In Flue Gases, Surendra Komar Kawatra, Timothy C. Eisele, John J. Simmons

Michigan Tech Patents

There is provided a process for the capture and sequestration of carbon dioxide that would otherwise enter the atmosphere and contribute to global warming and other problems. C02 capture is accomplished by reacting carbon dioxide in flue gas with an alkali metal carbonate, or a metal oxide, particularly containing an alkaline earth metal or iron, to form a carbonate salt. A preferred carbonate for C02 capture is a dilute aqueous solution of additive-free (Na2C03). Other carbonates include (K2C03) or other metal ion that can produce both a carbonate and a bicarbonate salt. Examples of suitable metal oxides include several alkaline …

Interactivity-Constrained Server Provisioning In Large-Scale Distributed Virtual Environments, Nguyen Binh Duong Ta, Thang Nguyen, Suiping Zhou, Xueyan Tang, Wentong Cai, Rassul Ayani

Research Collection School Of Computing and Information Systems

Maintaining interactivity is one of the key challenges in distributed virtual environments (DVE), e.g., online games, distributed simulations, etc., due to the large, heterogeneous Internet latencies; and the fact that clients in a DVE are usually geographically separated. In this paper, we consider a new problem, termed the interactivity-constrained server provisioning problem, whose goal is to minimize the number of distributed servers needed to achieve a pre-determined level of interactivity. We identify and formulate two variants of this new problem and show that they are both NP-hard via reductions to the set covering problem. We then propose several computationally efficient …

Oxygen Vacancies Adjacent To Cu(2+) Ions In Tio(2) (Rutile) Crystals, A. T. Brant, Shan Yang (杨山), Nancy C. Giles, Zafar Iqbal, A. Manivannan, Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to characterize Cu²⁺ ions substituting for Ti⁴⁺ ions in nominally undoped TiO₂ crystals having the rutile structure. Illumination at 25 K with 442 nm laser light reduces the concentration of Cu²⁺ ions by more than a factor of 2. The laser light also reduces the EPR signals from Fe³⁺ and Cr³⁺ ions and introduces signals from Ti³⁺ ions. Warming in the dark to room temperature restores the crystal to its preilluminated state. Monitoring the recovery of the photoinduced changes in the Cu …

Thermal Conductivity Of Interfacial Layers In Nanofluids, Zhi Liang, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Thermal Conductivity of Interfacial Layers is an Essential Parameter for Determining How the Ordered Liquid Layering Around the Particle-Liquid Interface Contributes to the Unusual High Thermal Conductivity of Nanofluids. However, So Far There is No Experimental Data Regarding This Parameter. using Nonequilibrium Molecular Dynamics Simulations of an Inhomogeneous Au-Ar System in Which the Solid-Liquid Interactions Are Assumed to Be Much Stronger Than the Liquid-Liquid Interactions, We Show Explicitly that the Thermal Conductivity of a 1-Nm-Thick Interfacial Layer is 1.6∼2.5 Times Higher Than that of the Base Fluid. the Simulation Results Are Incorporated into a Three-Level Clustering Model to Calculate the …

Single Molecule In Vivo Analysis Of Toll-Like Receptor 9 And Cpg Dna Interaction, Jiji Chen, Suman Nag, Pierre-Alexandre Vidi, Joseph Irudayaraj

Birck and NCN Publications

Toll-like receptor 9 (TLR9) activates the innate immune system in response to oligonucleotides rich in CpG whereas DNA lacking CpG could inhibit its activation. However, the mechanism of how TLR9 interacts with nucleic acid and becomes activated in live cells is not well understood. Here, we report on the successful implementation of single molecule tools, constituting fluorescence correlation/cross-correlation spectroscopy (FCS and FCCS) and photon count histogram (PCH) with fluorescence lifetime imaging (FLIM) to study the interaction of TLR9-GFP with Cy5 labeled oligonucleotide containing CpG or lacking CpG in live HEK 293 cells. Our findings show that i) TLR9 predominantly forms …

Long Term Outdoor Testing Of Low Concentration Solar Modules, Lewis Fraas, James Avery, Leonid Minkin, H. X. Huang, Tim Hebrink, Robert F. Boehm

Mechanical Engineering Faculty Research

A 1‐axis carousel tracker equipped with four 3‐sun low‐concentration mirror modules has now been under test outdoors at the University of Nevada in Las Vegas (UNLV) for three years. There are three unique features associated with this unit. First, simple linear mirrors are used to reduce the amount of expensive single crystal silicon in order to potentially lower the module cost while potentially maintaining cell efficiencies over 20% and high module efficiency. Simple linear mirrors also allow the use of a single axis tracker. Second, the azimuth carousel tracker is also unique allowing trackers to be used on commercial building …

Keynote 2: The Alberta Oil Sands — Wrestling Bitumen Out Of The Wild North, David Rudolph

North American Energy Water Nexus Roundtable

Athabasca Oil Sand Reserve:

- Oil sands are contained within the Cretaceous McMurray Formation. (149,000 km2)

- 2.5 trillion barrels of extractable oil (~ 25 % of Canada Crude Oil Production)

- Surface mineable deposits cover 2,800 km2

- 450 billion L of process water used annually

- Currently over 130 km2 of tailings ponds (largest man-made structures in the world)