Engineering Commons^™

Longwave Buckling Of Cold-Formed Steel Studs Using Direct Strength, Thomas Sputo

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Local And Distortional Buckling Of Cold-Formed Steel Studs Using Direct Strength, Jennifer Tovar

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Lateral Response Of Sheathed Cold-Formed Shear Walls An Analytical Approach, Gaetano Della Corte

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Introduction, Roger A. Laboube, Wei-Wen Yu

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Structural Behaviour Of High Strength Cold-Formed Steel Z Purlins With Overlaps, K. F. Chung, H. C. Ho

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Modeling And Data Analysis Of Conductive Polymer Composite Sensors, Hua Lei

Theses and Dissertations

Conductive polymer composite sensors have shown great potential in identifying gaseous analytes. To more thoroughly understand the physical and chemical mechanism of this type of sensors, a model was developed by combining two sub-models: a conductivity model and a thermodynamic model, which gives a relationship between the vapor concentration of analyte(s) and the change of the sensor signals. In this work, 64 chemiresistors representing eight different carbon concentrations (8–60 vol.% carbon) were constructed by depositing thin films of a carbon black–polyisobutylene composite onto concentric spiral platinum electrodes on a silicon chip. The responses of the sensors were measured in dry …

Measured Impacts Of Proper Air Conditioning Sizing In Four Florida Case Study Homes, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

Previous studies have shown that residential air-conditioning system oversizing is a common practice that has both energy and comfort penalties. A Florida Power and Light / Florida Solar Energy Center (FSEC) study involving over 350 homes found that 50% of the studies AC systems were over sized by 120% or more (James et al. 1997). The same study found oversizing AC systems by 1.0 to 1.2 times Manual J resulted in 3.7% higher cooling energy use and oversizing systems 1.2 to 1.5 times Manual J resulted in 9.3% higher cooling energy use.

The goal of Task 3.2, Benefits of Proper …

Characterization Of Error-Tolerant Applications When Protecting Control Data, Darshan D. Thaker, Diana Franklin, John Y. Oliver, Susmit Biswas, Derek Lockhart, Tzvetan Metodi, Frederic T. Chong

Electrical Engineering

Soft errors have become a significant concern and recent studies have measured the "architectural vulnerability factor" of systems to such errors, or conversely, the potential that a soft error is masked by latches or other system behavior. We take soft-error tolerance one step further and examine when an application can tolerate errors that are not masked. For example, a video decoder or approximation algorithm can tolerate errors if the user is willing to accept degraded output. The key observation is that while the decoder can tolerate error in its data, it can not tolerate error in its control. We first …

Evolution Of Surface Morphology Of Thermo-Mechanically Cycled Nicocraly Bond Coats, J. Shi, Anette M. Karlsson, B. Baufeld, M. Bartsch

Mechanical Engineering Faculty Publications

We investigate morphological surface instabilities on bond coat surfaces of thermal barrier coatings, induced due to thermo-mechanical loading. Experimental results of hollow circular cylindrical specimens, consisting of a directionally solidified superalloy (IN 100 DS) coated with a NiCoCrAlY bond coat, show that the morphological instabilities are strongly dependent on the load conditions. In particular, the morphological instabilities develop during thermal cycling with a thermal gradient over the cylinder wall, whereas the surface remains smooth for thermal cyclic conditions without a gradient. Furthermore, if a cyclic, axial tensile force is applied (synchronized with the thermal cycling), the morphological instabilities become aligned …

Atmospheric Chemistry Of A 33–34 Hour Old Volcanic Cloud From Hekla Volcano (Iceland): Insights From Direct Sampling And The Application Of Chemical Box Modeling, William I. Rose, Genevieve A. Millard, Tamsin A. Mather, Donald E. Hunton, Bruce Anderson, Clive Oppenheimer, Brett F. Thornton, Terrence M. Gerlach, Albert A. Viggiano, Yutaka Kondo, Thomas M. Miller, John O. Ballenthin

Department of Geological and Mining Engineering and Sciences Publications

On 28 February 2000, a volcanic cloud from Hekla volcano, Iceland, was serendipitously sampled by a DC-8 research aircraft during the SAGE III Ozone Loss and Validation Experiment (SOLVE I). It was encountered at night at 10.4 km above sea level (in the lower stratosphere) and 33–34 hours after emission. The cloud is readily identified by abundant SO2 (≤1 ppmv), HCl (≤70 ppbv), HF (≤60 ppbv), and particles (which may have included fine silicate ash). We compare observed and modeled cloud compositions to understand its chemical evolution. Abundances of sulfur and halogen species indicate some oxidation of sulfur gases but …

Investigation Of Device Parameters For Field-Effect Dna-Sensors By Three-Dimensional Simulation, Eddie Howell, Clemens Heitzinger, Gerhard Klimeck

Other Nanotechnology Publications

The development of a DNA field-effect transistor (DNAFET) simulator is described and implications on device structure and future experiments are discussed. In DNAFETs the gate structure is replaced by a layer of immobilized single-stranded DNA molecules which act as surface probe molecules [1, 2]. When complementary DNA strands bind to the receptors, the charge distribution near the surface of the device changes, modulating current transport through the device and enabling detection (cf. Fig. 1 and 5). Arrays of DNAFETs can be used for detecting singlenucleotide polymorphisms and for DNA sequencing. The advantage of DNAFETs over optical methods of detection is …

Cad/Fea Tools And The Analysis Of Design For Optimization, Patil Yogesh

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Patil Yogesh on October 21, 2006.

Assessment Of The Tube Suction Test For Identifying Non-Frost-Susceptible Soils Stabilized With Cement, Amy Lyn Crook

Theses and Dissertations

Frost heave is a primary mechanism of pavement distress in cold regions. The distress exhibited is dependent on the frost susceptibility of the soil within the depth of frost penetration, the availability of subsurface water, and the duration of freezing surface temperatures. Cement stabilization is one technique used to mitigate the effects of frost heave. The tube suction test (TST) is one possible method for determining the frost susceptibility of soils in the laboratory. The purpose of this research was to assess the utility of the TST for identifying non-frost-susceptible (NFS) materials stabilized with cement. This research investigated two aggregate …

Effects Of Middle Plane Curvature On Vibrations Of A Thickness-Shear Mode Crystal Resonator, J. S. Yang, Xiaomeng Yang, Joseph A. Turner, John A. Kosinski, Robert A. Pastore, Weiping Zhang

Department of Engineering Mechanics: Faculty Publications

We study the effects of a small curvature of the middle plane of a thickness-shear mode crystal plate resonator on its vibration frequencies, modes and acceleration sensitivity. Two-dimensional equations for coupled thickness-shear, flexural and extensional vibrations of a shallow shell are used. The equations are simplified to a single equation for thickness-shear, and two equations for coupled thickness-shear and extension. Equations with different levels of coupling are used to study vibrations of rotated Y-cut quartz and langasite resonators. The influence of the middle plane curvature and coupling to extension is examined. The effect of middle plane curvature on normal acceleration …

A Prototype Platform For Array Feed Development, James Richard Nagel

Theses and Dissertations

Radio frequency interference (RFI) is a growing problem for radio astronomers. One potential solution utilizes spatial filtering by placing an array of electrically small antennas at the focal plane of a parabolic reflector. This thesis documents the design and characterization of a prototype array feed and RF receiver that were used to demonstrate the spatial filtering principle. The array consists of a 7-element hexagonal arrangement of thickened dipole antennas tuned to a center frequency of 1600 MHz. The receiver is a two-stage, low-noise frequency mixer that is tunable over the entire L-band. This thesis also documents a new receiver design …

Task-Driven Multi-Formation Control For Coordinated Uav/Ugv Isr Missions, Herbert G. Tanner

Mechanical Engineering Faculty Publications

The report describes the development of a theoretical framework for coordination and control of combined teams of UAVs and UGVs for coordinated ISR missions. We consider the mission as a composition of an ordered sequence of subtasks, each to be performed by a different team. We design continuous cooperative controllers that enable each team to perform a given subtask and we develop a discrete strategy for interleaving the action of teams on different subtasks. The overall multi-agent coordination architecture is captured by a hybrid automaton, stability is studied using Lyapunov tools, and performance is evaluated through numerical simulations.

Why Don't People Read The Manual?, David G. Novick, Karen Ward

Departmental Papers (CS)

Few users of computer applications seek help from the documentation. This paper reports the results of an empirical study of why this is so and examines how, in real work, users solve their usability problems. Based on in-depth interviews with 25 subjects representing a varied cross-section of users, we find that users do avoid using both paper and online help systems. Few users have paper manuals for the most heavily used applications, but none complained about their lack. Online help is more likely to be consulted than paper manuals, but users are equally likely to report that they solve their …

What Users Say They Want In Documentation, David G. Novick, Karen Ward

Departmental Papers (CS)

While earlier work provided a partial view of users’ preferences about manuals, for most users in most work contexts the important question remains open: What do users want in documentation? This paper presents the results of a study in which a diverse cross-section of 25 users was interviewed in depth about their needs and preferences with respect to software help systems, whether printed or on-line, that they use at work. The study’s participants indicated that they preferred documentation, whether online or printed, that is easy to navigate, provides explanations at an appropriate level of technical detail, enables finding as well …

Fabrication Of Hollow Optical Waveguides On Planar Substrates, John P. Barber

Theses and Dissertations

This dissertation presents the fabrication of hollow optical waveguides integrated on planar substrates. Similar in principle to Bragg waveguides and other photonic crystal waveguides, the antiresonant reflecting optical waveguide (ARROW) is used to guide light in hollow cores filled with liquids or gases. Waveguides with liquid or gas cores are an important new building block for integrated optical sensors. The fabrication method developed for hollow ARROW waveguides makes use of standard microfabrication processes and materials. Dielectric layers are deposited on a silicon wafer using plasma-enhanced chemical vapor deposition (PECVD) to form the bottom layers of the ARROW waveguide. A sacrificial …

Agglomeration Of Bed Particles In Low-Temperature Black Liquor Gasification, Mark A. Woodruff

Theses and Dissertations

The increasing concern for emissions and pollutants from power generation plants has increased the desire for and the study of biomass fuels. Biomass combustion produces less carbon monoxide as well as other greenhouse gases. Black liquor is a byproduct from the Kraft process in making paper. Black liquor can be gasified and used as a fuel in recovery boilers and fluidized bed steam reformers. Recovery boilers have a low efficiency and are used today because of their reliability. Steam reformers have a much higher efficiency but they are a relatively new science and are not as reliable. One of the …

Imaging The Mechanical Stiffness Of Skin Lesions By In Vivo Acousto-Optical Elastography, Sean J. Kirkpatrick, Donald D. Duncan, Ruikang K. Wang, Molly Kulesz-Martin, Ken Lee

Electrical and Computer Engineering Faculty Publications and Presentations

Optical elastography is an imaging modality that relies on variations in the local mechanical properties of biological tissues as the contrast mechanism for image formation. Skin lesions, such as melanomas and other invasive conditions, are known to alter the arrangement of collagen fibers in the skin and thus should lead to alterations in local skin mechanical properties. We report on an acousto-optical elastography (AOE) imaging modality for quantifying the mechanical behavior of skin lesions. The method relies upon stimulating the tissue with a low frequency acoustic force and imaging the resulting strains in the tissue by means of quantifying the …

Potential Energy Surfaces For Small Alcohol Dimers I: Methanol And Ethanol, Richard L. Rowley, Tapani A. Pakkanen, Christopher M. Tracy

Faculty Publications

Potential energy landscapes for homogeneous dimers of methanol and ethanol were calculated using counterpoise (CP) corrected energies at the MP2/6-311+G(2df,2pd) level. The landscapes were sampled at approximately 15 dimer separation distances for different relative monomer geometries, or routes, given in terms of a relative monomer yaw, pitch, and roll and the spherical angles between the monomer centers (taken as the C atom attached to the O). The 19 different routes studied for methanol and the 22 routes examined for ethanol include 607 CP corrected energies. Both landscapes can be adequately represented by site-site, pairwise-additive models, suitable for use in molecular …

Synergistic Use Of Compound Properties And Docking Scores In Neural Network Modeling Of Cyp2d6 Binding: Predicting Affinity And Conformational Sampling, Peter S. Bazeley, Sridevi Prithivi, Craig Struble, Richard J. Povinelli, Daniel S. Sem

Electrical and Computer Engineering Faculty Research and Publications

Cytochrome P450 2D6 (CYP2D6) is used to develop an approach for predicting affinity and relevant binding conformation(s) for highly flexible binding sites. The approach combines the use of docking scores and compound properties as attributes in building a neural network (NN) model. It begins by identifying segments of CYP2D6 that are important for binding specificity, based on structural variability among diverse CYP enzymes. A family of distinct, low-energy conformations of CYP2D6 are generated using simulated annealing (SA) and a collection of 82 compounds with known CYP2D6 affinities are docked. Interestingly, docking poses are observed on the backside of the heme …

Composite (La, Sr)Mno3-Ysz Cathode For Sofc, Toshio Suzuki, Masanobu Awano, Piotr Jasinski, Vladimir Petrovsky, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

(La, Sr) MnO₃ (LSM)-Y doped ZrO₂ (YSZ) composite was prepared using YSZ colloidal suspension (initial YSZ particle size ∼100 nm), YSZ and LSM polymer precursors on dense substrates at 800 °C annealing temperature. the results of a symmetrical LSM-YSZ composite cell test showed the area specific resistance for overpotential of 0.14 Ω cm2 at 800 °C, which indicated that the LSM-YSZ composite could be a potential candidate for cathode in SOFCs. the performance of the cell with the LSM-YSZ composite cathode and Ni-YSZ anode was investigated and the power density of about 0.26 W cm- 2 was obtained …

Effect Of Friction Stir Processing On The Microstructure Of Cast A356 Aluminum, Z. Y. Ma, S. R. Sharma, Rajiv S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Friction stir processing (FSP) was applied to cast A356 Al to modify the as-cast microstructure. FSP homogenizes and refines the cast microstructure, completely eliminates porosity, and creates a microstructure with fine Si particles (0.25-0.42 μm) distributed in a fine grain aluminum matrix (3-4 μm). Further, FSP parameters significantly influence microstructural development in the processed zone of cast A356 Al. Generally, higher tool rotation rate creates a more homogeneous microstructure. at lower tool rotation rates, a macroscopically visible banded structure characterized by a low density of coarse particles, was detected in the nugget zone. However, FSP parameters did not significantly influence …

Halogen Emissions From A Small Volcanic Eruption: Modeling The Peak Concentrations, Dispersion, And Volcanically Induced Ozone Loss In The Stratosphere, G. A. Millard, T. A. Mather, D. M. Pyle, William I. Rose, B. Thornton

Department of Geological and Mining Engineering and Sciences Publications

Aircraft measurements in the Hekla, Iceland volcanic plume in February 2000 revealed large quantities of hydrogen halides within the stratosphere correlated to volcanic SO2. Investigation of the longer-term stratospheric impact of these emissions, using the 3D chemical transport model, SLIMCAT suggests that volcanic enhancements of H2O and HNO3 increased HNO3·3H2O particle availability within the plume. These particles activated volcanic HCl and HBr, enhancing model plume concentrations of ClOx (20 ppb) and BrOx (50 ppt). Model O3 concentrations decreased to near-zero in places, and plume average O3 remained 30% lower after two weeks. Reductions in the model O3column reduced UV shielding …

Denoising Of Imagery For Inspection Tasks Using Higher-Order Statistics, Samuel Peter Kozaitis

Electrical Engineering and Computer Science Faculty Publications

We reduced noise in images using a higher-order, correlation-based method. In this approach, wavelet coefficients were classified as either mostly noise or mostly signal based on third-order statistics. Because the higher than second-order moments of the Gaussian probability function are zero, the third-order correlation coefficient may not have a statistical contribution from Gaussian noise. Using a detection algorithm derived from third-order statistics, we determined if a wavelet coefficient was noisy by looking at its third-order correlation coefficient. Using imagery of space shuttle tiles, our results showed that the minimum mean-squared error obtained using third-order statistics was often less than that …

Rideshare Conference, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "RideShare Conference" from October 11, 2006.

Building America Industrialized Housing Partnership (Baihp), Final Project Report, September 1, 1999 - June 30, 2006, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

This final report summarizes the work conducted by the Building America Industrialized Housing Partnership (www.baihp.org ) for the period 9/1/99 - 6/30/06. BAIHP is led by the Florida Solar Energy Center of the University of Central Florida and focuses on factory built housing. In partnership with over 50 factory and site builders, work was performed in two main areas - research and technical assistance.

In the research area -- through site visits in over 75 problem homes, we discovered the prime causes of moisture problems in some manufactured homes and our industry partners adopted our solutions to nearly eliminate this …

Lagrangian Mixing In Decaying Stably Stratified Turbulence, Subhas K. Venayagamoorthy, Derek D. Stretch

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Direct numerical simulations are used to study mixing and dispersion in decaying stably stratified turbulence from a Lagrangian perspective. The change in density of fluid particles owing to small-scale mixing is extracted from the simulations to provide insight into the mixing process. These changes are driven by temporally and spatially intermittent events that are strongly suppressed as the stratification increases and overturning motions disappear. This occurs for times Nt > 2π i.e. after one buoyancy period, where N is the buoyancy frequency. The role of small-scale mixing processes in the density (or buoyancy) flux is analyzed. After an initial transient, we …