Engineering Commons^™

Sgdbr Single-Chip Wavelength Tunable Lasers For Swept Source Oct, Dennis J. Derickson, Mike Bernacil, Andrew Dekelaita, Ben Maher, Shane O'Connor, Mathew N. Sysak, Leif Johanssen

Electrical Engineering

Sampled Grating Distributed Bragg Reflector (SGDBR) monolithic tunable lasers are now entering the production phase in telecommunications applications. These tunable lasers are unique in that they offer wide wavelength tuning (1525 to 1565 nm), fast wavelength tuning (5 ns) and high speed amplitude modulation all on the same monolithic chip1,2,3,4. This work studies the applicability of SGDBR monolithic tunable laser diodes for biomedical imaging using swept-wavelength or Fourier domain optical coherence tomography. This paper will present our work involved with utilizing the strengths (table 1) of this SGDBR laser class and mitigating the weaknesses (table 2) of this device for …

Nanopatterning Using Nsom Probes Integrated With High Transmission Nanoscale Bowtie Aperture, Nicholas Murphy-Dubay, Liang Wang, Edward C. Kinzel, Sreemanth Mv Uppuluri, Xianfan Xu

Birck and NCN Publications

Nanoscale ridge aperture antennas have been shown to have high transmission efficiency and confined nanoscale radiation in the near field region compared with regularly-shaped apertures. The radiation enhancement is attributed to the fundamental electric-magnetic field propagating in the TE10 mode concentrated in the gap between the ridges. This paper reports experimental demonstration of field enhancement using such ridge antenna apertures in a bowtie shape for the manufacture of nanometer size structures using an NSOM (near field scanning optical microscopy) probe integrated with nanoscale bowtie aperture. Consistent lines with width of 59 nm and as small as 24 nm have be …

Cricket Satellite Project: Hall Elementary School, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Cricket Satellite Project: Hall Elementary School" from February 18, 2008.

Influence Of Spatial Correlation Function On Attenuation Of Ultrasonic Waves In Two-Phase Materials, Dalie Liu, Joseph A. Turner

Department of Engineering Mechanics: Faculty Publications

Successful processing of materials by powder sintering relies on the creation of strong interparticle bonds. During certain critical stages of the sintering process, the medium may be modeled as two phases consisting of the particles and a surrounding matrix. Ultrasonic methods have been proposed as a potential tool for monitoring such sintering processes. Thus, an understanding of the propagation and scattering of elastic waves in two-phase solids is of fundamental importance to these monitoring techniques. In this article, expressions for the ultrasonic attenuations are developed based on the spatial statistics of the density and Lamé parameters of the material constituents …

Observations Of Piezoresistivity For Polysilicon In Bending That Are Unexplained By Linear Models, Tyler L. Waterfall, Gary K. Johns, Robert K. Messenger, Brian D. Jensen, Timothy W. Mclain, Larry L. Howell

Faculty Publications

Compliant piezoresistive MEMS sensors exhibit great promise for improved on-chip sensing. As compliant sensors may experience complex loads, their design and implementation require a greater understanding of the piezoresistive effect of polysilicon in bending and combined loads. This paper presents experimental results showing the piezoresistive effect for these complex loads. Several n-type polysilicon test structures, fabricated in MUMPs and SUMMiT processes, were tested. Results show that, while tensile stresses cause a linear decrease in resistance, bending stresses induce a nonlinear rise in resistance, contrary to the effect predicted by linear models. In addition, tensile, compressive, and bending loads combine in …

A History Of Prescott's Ernest A. Love Field, Nancy Burgess

ERAU Prescott Aviation History Program

Learn about the Airport named for this hometown hero in "A History Of Prescott's Ernest A. Love Field" by City of Prescott's Preservation Specialist Nancy Burgess

Hydrogen Sensor Using Optical Reflectance From Porous Silicon With A Palladium Thin Film, Christopher G. Lowrie, Susan K. Earles, Maria E. Pozo De Fernandez

Electrical Engineering and Computer Science Faculty Publications

Results of a hydrogen sensor based on light scattering from a porous silicon surface coated with a thin palladium film are discussed. Reflected light scattered from the rough surface of porous silicon surface with a thin palladium film is compared before and after exposure to hydrogen gas. After exposure to hydrogen gas the sensor's optical reflectance is decreased indicating the presence of hydrogen.

Porous Silicon Surface Feature Size Estimation Using The Reflectance Spectrum, Christopher G. Lowrie, Susan K. Earles, Maria E. Pozo De Fernandez

Electrical Engineering and Computer Science Faculty Publications

In this paper we excite the surface of porous silicon with incoherent, broad band white light and observe the spectrum of colors reflected from the surface. Using an atomic force microscope images from red and green porous silicon samples are collected. In this paper we relate the optical color of the surface to the size of scattering features on the textured surface. From image segmentation using the watershed transform the height distributions of the optical scattering features are determined. The heights of these surface features are then used as input variables to a computer simulation of a reflective grating. The …

Davenport, Charles, 1862-1937 (Sc 1590), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "Additional Files" below) for Manuscripts Small Collection 1590. Letter to the editor (Park City Daily News?) by Charles Davenport, reminiscing about growing up in the Warren County, Kentucky community of Greencastle. Includes photos of James Ford and Thomas L. Stephens, builders of the Greencastle lock and dam on Barren River.

Characterizing The Three-Dimensional Behavior Of Bistable Micromechanisms, Brian B. Cherry

Theses and Dissertations

Compliant bistable micromechanisms have been proposed for use in applications such as switches, relays, shutters, and sensing arrays. Unpublished laboratory testing suggests that off-axis forces may affect the bistable nature of fully compliant bistable micromechanisms (FCBMs). The actuation forces required to snap the FCBM from one stable equilibrium position to another can be altered if the off-axis forces are applied to the mechanism during transition between stable positions. Understanding the three-dimensional characteristics of these mechanisms and the effect of eccentric loading conditions would be helpful in design and analysis of FCBMs. Two 3-D FEA models were developed for analysis and …

Ceas E-News 02.07.2008, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

Silicon carbide research examines nano-behavior of ceramics

Joint Image And Pupil Plane Reconstruction Algorithm Based On Bayesian Techniques, James D. Phillips

Theses and Dissertations

The focus of this research was to develop an joint pupil and focal plane image recovery algorithm for use with coherent LADAR systems. The benefits of such a system would include increased resolution with little or no increase in system weight and volume as well as allowing for operation in the absence of natural light since the target of interest would be actively illuminated. Since a pupil plane collection aperture can be conformal, such a system would also potentially allow for the formation of large synthetic apertures. The system is demonstrated to be robust and in all but extreme cases …

A Model For Predicting The Piezoresistive Effect In Microflexures Experiencing Bending And Tension Loads, Gary K. Johns, Larry L. Howell, Brian D. Jensen, Timothy W. Mclain

Faculty Publications

This paper proposes a model for predicting the piezoresistive effect in microflexures experiencing bending stresses. Linear models have long existed for describing piezoresistivity for members in pure tension and compression. However, extensions of linear models to more complex loading conditions do not match with experimental results. A second-order model to predict piezoresistive effects in tension, compression, and more complex loading conditions is proposed. A reduced form of the general second-order model is presented for thin flexures in bending. A three-step approach is used to determine the piezoresistive coefficients for this reduced-form model. The approach is demonstrated for two sets of …

Path Planning For Unmanned Air And Ground Vehicles In Urban Environments, Andrew B. Curtis

Theses and Dissertations

Unmanned vehicle systems, specifically unmanned air vehicles (UAVs) and unmanned ground vehicles (UGVs), have become a popular research topic. This thesis discusses the potential of a UAV-UGV system used to track a human moving through complex urban terrain. This research focuses on path planning problems for both a UAV and a UGV, and presents effective solutions for both problems. In the UAV path planning problem, we desire to plan a path for a miniature fixed-wing UAV to fly through known urban terrain without colliding with any buildings. We present the Waypoint RRT (WRRT) algorithm, which accounts for UAV dynamics while …

Computer Modeling And Analysis Of Thermal Link Performance For An Optical Refrigerator, Kevin Byram, David Mar, John Parker, Steven Von Der Porten, John Hankinson, Chris Lee, Kai Mayeda, Richard C. Haskell, Qimin Yang, Scott R. Greenfield, Richard I. Epstein

All HMC Faculty Publications and Research

We have used the thermal modeling tool in COMSOL Multiphysics to investigate factors that affect the thermal performance of the optical refrigerator. Assuming an ideal cooling element and a non-absorptive dielectric trapping mirror, the three dominant heating factors are blackbody radiation from the surrounding environment, conductive heat transfer through mechanical supports, and the absorption of fluorescent photons transmitted through the thermal link. Laboratory experimentation coupled with computer modeling using Code V optical software have resulted in link designs capable of reducing the transmission to 0.04% of the fluoresced photons emitted toward the thermal link. The ideal thermal link will have …

Nonlinear Contact Analysis Of Gear Teeth For Malfunction Diagnostics, D. Kong, J. M. Meagher, C. Xu, X. Wu, Y. Wu

Mechanical Engineering

Gearboxes sustain a variety of faults such as broken-shafts, eroded, broken, or missing teeth, and even broken-cases. Casing mounted accelerometers can detect fault patterns but the signals are complicated and difficult to interpret. This study considers the tooth loading of ideal gears and gears with defects. A large industrial gearbox used in a 12m³ electric mining shovel is modeled. The nonlinear contact mechanics is analyzed to predict the bearing supporting force variation vs. the gear tooth loading after a 3-D CAD model of the gearbox is transferred into multi-body dynamics software. The contact mechanics model of the meshing teeth …

Ccfss Technical Bulletin Spring 2008, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

Acuta Enews February 2008, Vol. 37, No. 2

ACUTA Newsletters

ln This lssue

From the President........ Walt Magnussen, Texas A&M Univ., ACUTA President

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Grant Money for Minority College Wireless Networks

Ethernet Alliance White Paper Challenge

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Welcome New Members

Specification For The Design, Testing, And Utilization Of Industrial Steel Storage Racks, Rack Manufacturers Institute

Rack Manufacturers Institute (RMI) Specifications and Manuals (1984 - 2012)

No abstract provided.

Commentary On The Specifications For The Design, Testing, And Utilization Of Industrial Steel Storage Racks, Rack Manufacturers Institute

Rack Manufacturers Institute (RMI) Specifications and Manuals (1984 - 2012)

No abstract provided.

Extracting Computable Bounds (And Algorithms) From Classical Existence Proofs: Girard Domains Enable Us To Go Beyond Local Compactness, Vladik Kreinovich, Karen Villaverde

Departmental Technical Reports (CS)

In classical mathematics, the existence of a solution is often proven indirectly, non-constructively, without an efficient method for constructing the corresponding object. In many cases, we can extract an algorithm from a classical proof: e.g., when an object is (non-constructively) proven to be unique in a locally compact space (or when there are two such objects with a known lower bound on the distance between them). In many other practical situations, a (seemingly) natural formalization of the corresponding practical problem leads to a non-compact set. In this paper, we show that often, in such situations, we can extract efficient algorithms …

Identification Of Human Gait In Neuro-Rehabilitation: Towards Efficient Algorithms, Naga Suman Kanagala, Martine Ceberio, Thompson Sarkodie-Gyan, Vladik Kreinovich, Roberto Araiza

Departmental Technical Reports (CS)

Many neurological diseases such as stroke, traumatic body injury, spinal cord injury drastically decrease the patient's ability to walk without physical assistance. To re-establish normal gait, patients undergo extensive rehabilitation. At present, rehabilitation requires gait assessment by highly qualified experienced clinicians. To make rehabilitations easier to access and to decrease the rehabilitation cost, it is desirable to automate gait assessment. In precise terms, gait assessment means comparing the recorded patient's gait with a standard (average) gait of healthy people of the same body measurements. One of the problems in this comparison is that patients walk slower; so, to properly compare …

Integrating Random Testing With Constraints For Improved Efficiency And Diversity, Yoonsik Cheon, Antonio Cortes, Martine Ceberio, Gary T. Leavens

Departmental Technical Reports (CS)

Random testing can be fully automated, eliminates subjectiveness in constructing test cases, and increases the diversity of test data. However, randomly generated tests may not satisfy program's assumptions (e.g., method preconditions). While constraint solving can satisfy such assumptions, it does not necessarily generate diverse tests and is hard to apply to large programs. We blend these techniques by extending random testing with constraint solving, improving the efficiency of generating valid test data while preserving diversity. For domains such as objects, we generate input values randomly; however, for values of finite domains such as integers, we represent test data generation as …

A Spy Under The Hood: Controlling Risk And Automotive Edr, Peter R. Thom, C. Arthur Maccarley

Electrical Engineering

No abstract provided.

Bifidobacteria In Feces And Environmental Waters, Regina Lamendella, Jorge W. Santo Domingo, Catherine A. Kelty, Daniel B. Oerther

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Bifidobacteria have been recommended as potential indicators of human fecal pollution in surface waters even though very little is known about their presence in nonhuman fecal sources. The objective of this research was to shed light on the occurrence and molecular diversity of this fecal indicator group in different animals and environmental waters. Genus- and species-specific 16S rRNA gene PCR assays were used to study the presence of bifidobacteria among 269 fecal DNA extracts from 32 different animals. Twelve samples from three wastewater treatment plants and 34 water samples from two fecally impacted watersheds were also tested. The species-specific assays …

A Library-Based Approach To Translating Ocl Constraints To Jml Assertions For Runtime Checking, Carmen Avila, Guillermo Flores, Jr., Yoonsik Cheon

Departmental Technical Reports (CS)

OCL is a formal notation to specify constraints on UML models that cannot otherwise be expressed by diagrammatic notations such as class diagrams. Using OCL one can document detailed design decisions and choices along with the behavior, e.g., class invariants and method pre and postconditions. However, OCL constraints cannot be directly executed and checked at runtime by an implementation, thus constraint violations may not be detected or noticed, causing many potential development and maintenance problems. In this paper we propose an approach to checking OCL constraints at runtime by translating them to executable JML assertions. The key components of our …

Effects Of Climate Change On Energy Production And Use In The United States, Thomas Wilbanks, Vatsal Bhatt, Daniel Bilello, Stanley Bull, James Ekmann, William Horak, Y. Joe Huang, Mark D. Levine, Michael J. Sale, David Schmalzer, Michael J. Scott

United States Department of Energy: Publications

Climate change is expected to have noticeable effects in the United States: a rise in average temperatures in most regions, changes in precipitation amounts and seasonal patterns in many regions, changes in the intensity and pattern of extreme weather events, and sea level rise. Some of these effects have clear implications for energy production and use. For instance, average warming can be expected to increase energy requirements for cooling and reduce energy requirements for warming. Changes in precipitation could affect prospects for hydropower, positively or negatively. Increases in storm intensity could threaten further disruptions of the sorts experienced in 2005 …

Effects Of Climate Change On Aquatic Invasive Species And Implications For Management And Research, Roxanne Thomas, Austin Kane, Environmental Law Institute, Britta G. Bierwagen

United States Environmental Protection Agency: Publications

Global change stressors, including climate change and variability and changes in land use, are major drivers of ecosystem alterations. Invasive species, which are non-native species that cause environmental or economic damages or human-health impacts, also contribute to ecosystem changes. The interactions between stressors and invasive species, although not well understood, may exacerbate the impacts of climate change on ecosystems, and likewise, climate change may enable further invasions. This report reviews available literature on climate-change effects on aquatic invasive species (AIS) and examines state-level AIS management activities. Data on management activities came from publicly available information, was analyzed with respect to …

High Voltage Charging Of A Capacitor Bank, Sergey I. Shkuratov, Jason Baird, Evgueni F. Talantsev, A. V. Ponomarev, Larry L. Altgilbers

Mining Engineering Faculty Research & Creative Works

We have demonstrated the feasibility of charging a capacitor bank to a high voltage using an autonomous ultra-compact explosively driven source of prime power. The prime power source is a longitudinally driven shock wave depolarization of a ferroelectric ceramic. The energy-carrying elements of the shock wave ferroelectric generators (FEGs) were poled Pb(Zr52Ti48)O3 polycrystalline ceramic disks with 0.35 cm3 volume. FEGs charged 9 nF, 18 nF, and 36 nF capacitor banks and provided pulsed-power with peak amplitudes up to 0.29 MW. The maximum efficiency of electric charge transfer from shocked Pb(Zr52Ti48)O3 elements to a capacitor bank was 46%. We demonstrated experimentally …

Low Complexity Soft-Input Soft-Output Block Decision Feedback Equalization, Jingxian Wu, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A low complexity soft-input soft-output (SISO) block decision feedback equalizer (BDFE) is presented for turbo equalization. The proposed method employs a sub-optimum sequence-based detection, where the soft-output of the equalizer is calculated by evaluating an approximation of the sequence-based a posteriori probability (APP) of the data symbol. The sequence-based APP approximation is enabled by the adoption of both soft a priori information and soft decision feedback, and it leads to better performance and faster convergence compared to symbol-based detection methods as used by most other low complexity equalizers. The performance and convergence property of the proposed algorithm is analyzed by …