Engineering Commons^™

Giant Magnetostriction In Annealed Co1-XFeX Thin-Films, Dwight Hunter, Will Osborn, Ke Wang, Nataliya Kazantseva, Jason R. Hattrick-Simpers, Richard Suchoski, Ryota Takahashi, Marcus L. Young, Apurva Mehta, Leonid A. Bendersky, Same E. Lofland, Manfred Wuttig, Ichiro Takeuchi

Faculty Publications

Chemical and structural heterogeneity and the resulting interaction of coexisting phases can lead to extraordinary behaviours in oxides, as observed in piezoelectric materials at morphotropic phase boundaries and relaxor ferroelectrics. However, such phenomena are rare in metallic alloys. Here we show that, by tuning the presence of structural heterogeneity in textured Co_1−xFe_x thin films, effective magnetostriction λeff as large as 260 p.p.m. can be achieved at low-saturation field of ~10 mT. Assuming λ100 is the dominant component, this number translates to an upper limit of magnetostriction ofλ100≈5λeff >1,000 p.p.m. Microstructural analyses …

Development Of Alternative Wood-Post Mgs Approach Guardrail Transition, Scott K. Rosenbaugh, Kevin D. Schrum, Ronald K. Faller, Karla A. Lechtenberg, Dean L. Sicking, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.

Impacts Of Plug-In Electric Vehicle On Residential Electric Distribution System Using Stochastic And Sensitivity Approach, Henry Chigozie Ureh

Master's Theses

Plug-in Electric Vehicles (PEVs) are projected to become a viable means of transportation due to advances in technology and advocates for green and eco-friendly energy solutions. These vehicles are powered partially, or in some cases, solely by the energy stored in their battery packs. The large sizes of these battery packs require large amount of energy to charge, and as the demand for PEV increases, the increase in energy demand needed to recharge these PEV batteries could pose problems to the present electric distribution system. This study examines the potential impacts of PEV on a residential electric distribution system at …

Formulation Of An Optimal Search Strategy For Space Debris At Geo, Daniel J. Jackson

Master's Theses

The purpose of this thesis is to create a search strategy to find orbital debris when the object fails to appear in the sky at its predicted location. This project is for NASA Johnson Space Center Orbital Debris Program Office through the MODEST (Michigan Orbital Debris Survey Telescope) program. This thesis will build upon the research already done by James Biehl in “Formulation of a Search Strategy for Space Debris at GEO.” MODEST tracks objects at a specific right ascension and declination. A circular orbit assumption is then used to predict the location of the object at a later time. …

Nonlinear Progressive Wave Equation For Stratified Atmospheres, B. Edward Mcdonald, Andrew A. Piacsek

All Faculty Scholarship for the College of the Sciences

The nonlinear progressive wave equation (NPE) [McDonald and Kuperman, J. Acoust. Soc. Am. 81, 1406–1417 (1987)] is expressed in a form to accommodate changes in the ambient atmospheric density, pressure, and sound speed as the time-stepping computational window moves along a path possibly traversing significant altitude differences (in pressure scale heights). The modification is accomplished by the addition of a stratification term related to that derived in the 1970s for linear range-stepping calculations and later adopted into Khokhlov-Zabolotskaya-Kuznetsov-type nonlinear models. The modified NPE is shown to preserve acoustic energy in a ray tube and yields analytic similarity solutions for …

Thermodynamics Of Magnetic Multilayers, Tathagata Mukherjee

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Our interest in thermodynamics of magnetic thin film heterostructure began by exploring the possibility to use magnetic nanostructures in the search for optimized magnetocaloric materials for potential room temperature refrigeration. In the present thesis magnetic thin film heterostructures are experimentally realized by Molecular Beam Epitaxy (MBE) and Pulsed Laser Deposition (PLD). Co/Cr and Fe/Cr superlattices were fabricated using mean-field theoretical concepts as guiding principles. The potential of artificial antiferromagnets for near room-temperature refrigeration is explored. Magnetocaloric properties are deduced from measurements of the temperature and field dependence of the magnetization of our samples. The effects of intra-plane and inter-plane exchange …

Comparison Of Microwave And Conventionally Sintered Yttria-Doped Zirconia Ceramics, Colin J. Reidy, Thomas J. Fleming, Stuart Hampshire, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

This paper reports on improvement of the physical and mechanical properties of Y₂O₃-ZrO₂ ceramics through compositional optimization, the use of nanograined powders and utilization of microwave sintering. ZrO₂ with 2-5 mol% Y₂O₃, prepared from nanopowders, was sintered in both conventional and microwave furnaces under exactly the same heating schedule. It was found that microwave sintering improves physical and mechanical properties of Y₂O₃-ZrO₂ ceramics compared with conventional sintering. Compositions containing 2 mol% Y₂O₃ exhibit the greatest improvement due to retention of tetragonal ZrO …

An Evaluation Of Cmos Adders For Robustness And Fault Detectability In Nanoscale Technologies, Sowjanya Puttagunta

Electrical Engineering Theses

The objective of this thesis is to implement the two low transistor count full adders using submicron CMOS technologies and to study their performance with respect to process variations and single-transistor faults. One adder uses 10 transistors and the other uses 14 transistors. Hence they are respectively called the 10T and 14T adders. Previous work has studied the implementation of the static Complementary Metal Oxide Semiconductor (CMOS) adder, Complementary Pass Transistor Logic (CPL) adder, Transmission Gate adder (TGA) and the Hybrid CMOS (HCMOS) adder. The performance of the 10T and 14 T adders using the above mentioned metrics are compared …

Strengthening Of Steel Beams Using Mechanically Anchored Carbon Fiber Reinforced Polymers Laminates, Mohammed Monir Makin Ajan Alhadid

Theses

على مدى العقدين المنصرمين من الزمن تم إستخدام الألياف البلاستيكية المسلحة بشكل فعال و عملي في تقوية وتدعيم المنشأت الهندسية المختلفة بما في ذلك العناصر الإنشائية الخرسانية والطابوقية والخشبية, وطوال هذه الفترة الزمنية جرت أبحاث مفصلة حول العالم لدراسة مدى فاعلية مثل هذه الألياف في تقوية العناصر المعدنية و ذلك عن طريق تثبيتها بواسطة مواد شديدة الإلتصاقو ولقد كشفت الدراسات المنشورة أن هذه الطريقة في التثبيت سواءً في العناصر الخرسانية أو العناصر المعدنية تؤدي الي الانهيار الفجائي للعناصر المدعمة عند قيم التحميل المرتفعة ما لم يتم اتخاذ احتياطات أخرى وخصوصاً عند أطراف هذه الألياف، وبالمقابل فإن هناك دراسات أخرى أجريت …

Processing And Dielectric Properties Of Tio2 Thick Films For High-Energy Density Capacitor Applications, Sheng Chao, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Nanosized titanium dioxide (TiO₂) powders (∼40 nm) were used for preparation of tape-casting slurries. Effect of various solvents and dispersants on the dispersibility of TiO₂ slurries was studied by sedimentation tests and rheology measurements. TiO₂ green tapes were prepared by tape-casting method and densified at 1000°C with a sintered density >95%. Dielectric properties of TiO₂ tapes were studied by measuring of dielectric constant, loss factor and dielectric breakdown strength (BDS) with respect to their microstructural development. BDS values as high as ∼1400 kV/cm were obtained for sintered tapes so that energy densities up to 14 …

Finite Element Based Generalized Impedance Boundary Condition For Complicated Em Calculation, Shiquan He, Zaiping Nie, Jun Zh Huang, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a finite element based generalized impedance boundary condition (FEM-GIBC) is proposed to solve complicated electromagnetic (EM) problems. Complex structures with arbitrary inhomogeneity and shapes are modeled with the finite element method, and their scattering contributions are transformed to generalized impedance conditions on their boundaries. For each sub-domain, a special GIBC can be established and it is only related to the structures in this domain. Hence, for finite periodic structures, a representative GIBC can be formulated at the boundary of a unit cell. After the GIBC at each boundary is established, the electromagnetic coupling between each impedance boundary …

Reflection And Transmission Of Line-Source Excited Pulsed Em Fields At A Thin, High-Contrast Layer With Dielectric And Conductive Properties, Adrianus T. De Hoop, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A methodology is presented for analytically modeling the reflection and transmission of line-source excited pulsed electromagnetic fields fields at a thin, planar, high-contrast layer with dielectric and conductive properties. Closed-form time-domain expressions are derived for the field components in a two-dimensional setting via an extension of the Cagniard-DeHoop method. © 2011 IEEE.

Finite-Width Gap Excitation And Impedance Models, Yat Hei Lo, Shiquan He, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we present a new method for the feed model for the method of moments (MoM). It is derived from a more accurate model with the realistic size of the excitation, in order to replace the commonly-used delta-gap excitation model. This new model is formulated around the electric field integration equations (EFIE) where the terms for magnetic current and magnetic field can be removed. Hence it is much simpler to implement and reduces the numerical complexity. In addition, a variational formulation is derived to provide second order accuracy of the input admittance calculation. Moreover, this new formulation can …

Bs News November/December

Building Services Engineering

No abstract provided.

Poincaré Sphere Representation Of The Fixed-Polarizer Rotating-Retarder Optical System, R. M.A. Azzam

Electrical Engineering Faculty Publications

The trajectory of the polarization state of a monochromatic light beam after it passes through a fixed linear polarizer and a rotating linear retarder of arbitrary retardance Δ is determined on the Poincaré sphere. The three-dimensional figure-8 contour is shown to be the line of intersection of a right-circular cylinder with the sphere. The cylinder is parallel to the polar (s₃) axis, touches the sphere at the equator (at the point that represents the linear polarization transmitted by the fixed polarizer), and has a radius r=sin²(Δ/2). Projections of the trajectory in the coordinate planes of the …

Refining Greenstep: Impacts Of Vehicle Technologies And Its/Operational Improvements On Travel Speed And Fuel Consumption Curves, Kelly Clifton, Alexander Y. Bigazzi

Civil and Environmental Engineering Faculty Publications and Presentations

This report describes analysis undertaken to establish a method for incorporating traffic operations and ITS strategies into the GreenSTEP model. We first discuss operations impacts on fuel economy and delay from the literature. Then, an investigation of delay adjustments in GreenSTEP shows that different methods of representing delay changes lead to similar (and small) impacts on fuel economy. From this result we establish average speed adjustment by congestion level as the preferred method for incorporating delay effects from operations improvements. An investigation of aggregate traffic operations impacts produces estimates of base speeds without operations improvements, maximum speeds with full operational …

Wavelength Dependence Of Transverse Mode Coupling With/Without E-Block Of Gan Laser Cavity, Krishneel Lal

Electrical Engineering

No abstract provided.

Themed Ride Vehicle Concept Design, Ryan Alletag

Liberal Arts and Engineering Studies

No abstract provided.

Sensing With The Motor Cortex, Nicholas G. Hatsopoulos, Aaron J. Suminski

Biomedical Engineering Faculty Research and Publications

The primary motor cortex is a critical node in the network of brain regions responsible for voluntary motor behavior. It has been less appreciated, however, that the motor cortex exhibits sensory responses in a variety of modalities including vision and somatosensation. We review current work that emphasizes the heterogeneity in sensorimotor responses in the motor cortex and focus on its implications for cortical control of movement as well as for brain-machine interface development.

Cutting Tool Insert Having Internal Microduct For Coolant, William J. Endres

Michigan Tech Patents

A cutting tool insert includes: a body defining a rake face, a flank face, and a cutting edge at an intersection of the rake and flank faces; and a cooling microduct within the body. The microduct has a cross-sectional area of not more than 1.0 square millimeter. The microduct is adapted to permit the flow of a coolant therethrough to transfer heat away from the cutting edge and extend the useful life of the insert. The microduct may have a portion with a cross-sectional area no larger than 0.004 square millimeter, and may communicate through at least one of the …

Simulation And Fabrication Of 3d Spiral Photonic Crystals As Circular Polarizers, Xuejian Li

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Three-dimensional (3D) spiral photonic crystals (PhCs) have a periodic varied refractive index (RI) with the periodicity comparable to the wavelength of incident light. They can pass circularly polarized (CP) light with handedness opposite to their own structures’ handedness while block the polarization state with the same handedness. Three-dimensional spiral PhCs for use as circular polarizers have two main advantages over conventional circular polarizers. On the one hand, it has wide operation wavelength based on the photonic band gap caused by PhCs and the interaction between CP light and each individual spiral structure. On the other hand, the height of each …

Neutron Imaging And Applications: A Reference For The Imaging Community, Edmund Perfect, Chu-Lin Cheng, Peter Lehmann

Civil Engineering Faculty Publications

No abstract provided.

Extending Integral Concepts To Curved Bridge Systems, Saeed Eghtedar Doust

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The behavior of integral abutment systems and the extension of their application to curved bridges are investigated. First, the stresses in the elements of a typical integral abutment are studied by conducting nonlinear finite element analysis using the software package Abaqus. The results are design recommendations for the details of such abutments. The effect of integral abutments on the responses of bridges is also investigated. Steel and concrete bridge systems are studied separately.

The studied steel bridge systems are composed of composite I-girder superstructures and integral abutments supported on steel H-piles. A series of finite element studies for different bridge …

Seamless Bridge And Roadway System For The U.S. Practice, Nima Ala

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Expansion joints are one of the main causes for high maintenance costs in bridges. The search for ideal expansion joints has proven fruitless. That is why it has been said that “the best joint is no joint”. A seamless bridge system is envisioned that results in bridges with long service lives by eliminating the joints over the entire length of the bridge, approach slab and a segment of the roadway called transition. All bridge thermal movements are dissipated to zero in the transition. The system is similar to a system developed in Australia but modifications had to be made to …

A Pomdp Model For Guiding Taxi Cruising In A Congested Urban City, Lucas Agussurja, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We consider a partially observable Markov decision process (POMDP) model for improving a taxi agent cruising decision in a congested urban city. Using real-world data provided by a large taxi company in Singapore as a guide, we derive the state transition function of the POMDP. Specifically, we model the cruising behavior of the drivers as continuous-time Markov chains. We then apply dynamic programming algorithm for finding the optimal policy of the driver agent. Using a simulation, we show that this policy is significantly better than a greedy policy in congested road network.

Effect Of Sensory Feedback From The Proximal Upper Limb On Voluntary Isometric Finger Flexion And Extension In Hemiparetic Stroke Subjects, Gilles Hoffmann, Brian D. Schmit, Jennifer H. Kahn, Derek G. Kamper

Biomedical Engineering Faculty Research and Publications

This study investigated the potential influence of proximal sensory feedback on voluntary distal motor activity in the paretic upper limb of hemiparetic stroke survivors and the potential effect of voluntary distal motor activity on proximal muscle activity. Ten stroke subjects and 10 neurologically intact control subjects performed maximum voluntary isometric flexion and extension, respectively, at the metacarpophalangeal (MCP) joints of the fingers in two static arm postures and under three conditions of electrical stimulation of the arm. The tasks were quantified in terms of maximum MCP torque [MCP flexion (MCP_flex) or MCP extension (MCP_ext)] and activity …

Patterns Of Hypermetria And Terminal Cocontraction During Point-To-Point Movements Demonstrate Independent Action Of Trajectory And Postural Controllers, Robert A. Scheidt, Claude Ghez, Supriya Asnani

Biomedical Engineering Faculty Research and Publications

We examined elbow muscle activities and movement kinematics to determine how subjects combine elementary control actions in performing movements with one and two trajectory segments. In reaching, subjects made a rapid elbow flexion to a visual target before stabilizing the limb with either a low or a higher level of elbow flexor/extensor coactivity (CoA), which was cued by target diameter. Cursor diameter provided real-time biofeedback of actual muscle CoA. In reversing, the limb was to reverse direction within the target and return to the origin with minimal CoA. We previously reported that subjects overshoot the goal when attempting a reversal …

Gait Verification Using Knee Acceleration Signals, L. W. Hang, C. Y. Hong, C. W. Yen, D. J. Chang, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

A novel gait recognition method for biometric applications is proposed. The approach has the following distinct features. First, gait patterns are determined via knee acceleration signals, circumventing difficulties associated with conventional vision-based gait recognition methods. Second, an automatic procedure to extract gait features from acceleration signals is developed that employs a multiple-template classification method. Consequently, the proposed approach can adjust the sensitivity and specificity of the gait recognition system with great flexibility. Experimental results from 35 subjects demonstrate the potential of the approach for successful recognition. By setting sensitivity to be 0.95 and 0.90, the resulting specificity ranges from 1 …

Implementation And Validation Of The Ζ-F And Asbm Turbulence Models, Dustin Van Blaricom Quint

Master's Theses

The use of Computational Fluid Dynamics (CFD) tools throughout the engineering industry has become standard. Simulations are used during nearly all steps throughout the life cycle of products including design, production, and testing. Due to their wide range of use, industrial CFD codes are becoming more flexible and easier to use. These commercial codes require robustness, reliability, and efficiency. Consequently, linear eddy viscosity models (LEVM) are used to model turbulence for an increasing number of flow types. LEVM such as k-ε and k-ω provide modeling with little loss of computational efficiency and have proven to be robust. The LEVM that …

Detecting Suspicious Behavior With Low-Cost Sensors, Ahren Alexander Reed

Master's Theses

A proof of concept is created that demonstrates how low-cost sensors and a simple software solution can be used to proactively detect IED placement. The main goal is to detect suspicious behavior; Specifically we derive requirements that loitering, meandering, improper location and object placement shall be detected. Current methods being used to detect Improvised Explosive Devices (IEDs) are costly in terms of equipment and risk to life, and many are retroactive; IED detection occurs long after explosives are placed. A prototype system is explored with the quality attributes of being low-cost, proactive and using simple software methods. A wireless sensor …