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2011

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Articles 1471 - 1500 of 5801

Full-Text Articles in Engineering

Prediction Of Fluid Dielectric Constants, Jiangping Liu Jul 2011

Prediction Of Fluid Dielectric Constants, Jiangping Liu

Theses and Dissertations

The dielectric constant or relative static permittivity of a material represents the capacitance of the material relative to a vacuum and is important in many industrial applications. Nevertheless, accurate experimental values are often unavailable and current prediction methods lack accuracy and are often unreliable. A new QSPR (quantitative structure-property relation) correlation of dielectric constant for pure organic chemicals is developed and tested. The average absolute percent error is expected to be less than 3% when applied to hydrocarbons and non-polar compounds and less than 18% when applied to polar compounds with dielectric constant values ranging from 1.0 to 50.0. A …


Mechanical Characterization Of The Interspinous Ligament Using Anisotropic Small Punch Testing, Rachel Jane Bradshaw Jul 2011

Mechanical Characterization Of The Interspinous Ligament Using Anisotropic Small Punch Testing, Rachel Jane Bradshaw

Theses and Dissertations

Objective: The objective of this work was to characterize the nonlinear anisotropic material constitutive response of the interspinous ligament (ISL).

Methods: Cadaveric test samples of the interspinous ligament were tested using the anisotropic small punch test. The measured force-displacement response served as experimental input into a system identification optimization routine to determine the constitutive material parameters that replicated the measured material response.

Results: The constitutive behavior of the ISL is notably different from that reported for knee, shoulder, and hip ligaments. Specifically, the high collagen fiber content and unique collagen architecture provided a stiffer material response. The results from the …


Friction Bit Joining Of 5754 Aluminum To Dp980 Ultra-High Strength Steel: A Feasibility Study, Britney Weickum Jul 2011

Friction Bit Joining Of 5754 Aluminum To Dp980 Ultra-High Strength Steel: A Feasibility Study, Britney Weickum

Theses and Dissertations

In this study, the dissimilar metals 5754 aluminum and DP980 ultra-high strength steel were joined using the friction bit joining (FBJ) process. The friction bits were made using one of three steels: 4140, 4340, or H13. Experiments were performed in lap shear, T-peel, and cross tension configurations, with the 0.070" thick 5754 aluminum alloy as the top layer through which the friction bit cut, and the 0.065" thick DP980 as the bottom layer to which the friction bit welded. All experiments were performed using a computer controlled welding machine that was purpose-built and provided by MegaStir Technologies. Through a series …


Periodically Changing Morphology Of The Growth Interface In Si, Ge, And Gap Nanowires, C-Y Wen, J. Tersoff, K. Hillerich, M.C. Reuter, J. H. Park, S. Kodambaka, Eric Stach, F.M. Ross Jul 2011

Periodically Changing Morphology Of The Growth Interface In Si, Ge, And Gap Nanowires, C-Y Wen, J. Tersoff, K. Hillerich, M.C. Reuter, J. H. Park, S. Kodambaka, Eric Stach, F.M. Ross

Birck and NCN Publications

Nanowire growth in the standard < 111 > direction is assumed to occur at a planar catalyst-nanowire interface, but recent reports contradict this picture. Here we show that a nonplanar growth interface is, in fact, a general phenomenon. Both III-V and group IV nanowires show a distinct region at the trijunction with a different orientation whose size oscillates during growth, synchronized with step flow. We develop an explicit model for this structure that agrees well with experiment and shows that the oscillations provide a direct visualization of catalyst supersaturation. We discuss the implications for wire growth and structure.


Characterization Of The Mechanical Response Of The Lumbar Spine, Shannon Alisa Zirbel Jul 2011

Characterization Of The Mechanical Response Of The Lumbar Spine, Shannon Alisa Zirbel

Theses and Dissertations

The primary objective of this research is to associate lumbar segmental mechanical response with intervertebral disc degeneration under physiologic testing conditions. Because no mathematical model exists for lumbar spine segmental rotations, a portion of this thesis evaluates potential methods for curve fitting the torque-rotation curves. The Dual Inflection Point (DIP) Boltzmann equation was developed during the course of this research and is presented here as a method for fitting spinal motion data wherein a physical meaning can be assigned to each of the model coefficients. This model can tell us more about the effects of degeneration, testing conditions, and other …


Thermoelectric Power Factor Of In2O3:Pd Nanocomposite Films., Otto J. Gregory, Matin Amani, Gustave C. Fralick Jul 2011

Thermoelectric Power Factor Of In2O3:Pd Nanocomposite Films., Otto J. Gregory, Matin Amani, Gustave C. Fralick

Chemical, Biomolecular, and Materials Engineering Faculty Publications

A nanocomposite exhibiting large thermoelectric powers and capable of operating at temperatures as high as 1100 °C in air was fabricated by embedding palladium nanoparticles into an indium oxide matrix via co-sputtering from metal and ceramic targets. Combinatorial chemistry techniques were used to systematically investigate the effect of palladium content in these nanocomposite films on thermoelectric response. Based on these rapid screening experiments, the thermoelectric properties of the most promising nanocomposites were evaluated as a function of post-deposition heat treatment at high temperatures. An n-type nanocomposite film was developed exhibiting a power factor of 4.5 x 10-4 W/m·K2 …


Green Building Policy, School Performance, And Educational Leaders’ Perspectives In Usa, Scott D. Kelting, Michael Montoya Jul 2011

Green Building Policy, School Performance, And Educational Leaders’ Perspectives In Usa, Scott D. Kelting, Michael Montoya

Construction Management

The movement to construct high performance “green” buildings has had unprecedented market growth and continues to become mainstream practice for constructing schools in the United States. Green schools have economic, environmental and health benefits. Research provides information on the use of increased student performance found in green schools to justify building schools to a higher standard of indoor environment quality. There is clear and compelling evidence that schools currently built to specific green standards of indoor environmental quality, (e.g. thermal comfort, indoor air quality, acoustics and lighting,) result in healthier and more productive students and teachers. Current green building policies …


Florida Solar Atlas, Florida Solar Energy Center, Charles Cromer Jul 2011

Florida Solar Atlas, Florida Solar Energy Center, Charles Cromer

FSEC Energy Research Center®

The direct beam and direct global solar resource values for any geographical location in Florida were found by using actual data taken at the Florida Solar Energy Center (FSEC) for 2010 and correlating those values against clearness values derived from NOAA geostationary satellite data. Using the correlations developed, eleven years of satellite data (2000 - 2010) were used to provide expected monthly average solar resource values for any location in Florida. These values as provided in watts per meter square per day, were matched to colors with the lowest values of the full range of average values representing the deepest …


A Digital Hydraulic Valve, Actuated Using A Piezoelectric Linear Motor, Brian C. Bevill Jul 2011

A Digital Hydraulic Valve, Actuated Using A Piezoelectric Linear Motor, Brian C. Bevill

Purdue Polytechnic Directed Projects

Proportional control in hydraulics is widely utilized. The most widely used current types of proportional valves utilize solenoid technology. While this technology has been around for decades and has been proven an effective means of control, there is always a demand for improved performance of advancing technologies. Integrating piezoelectric devices as a means to control hydraulic systems helps advance control for hydraulic systems.

Piezoelectric stack devices have been used to control hydraulic systems with success. Advantages of these stacks include being relatively small with a high power to weight ratio, using less energy than solenoid operations, and being fast acting. …


Apparatus For Dispensing Material, Peter Werner Sutter, Eli Anguelova Sutter Jul 2011

Apparatus For Dispensing Material, Peter Werner Sutter, Eli Anguelova Sutter

Department of Electrical and Computer Engineering: Faculty Publications

An apparatus capable of dispensing drops of material with volumes on the order of Zeptoliters is described. In some embodiments of the inventive pipette the size of the droplets so dispensed is determined by the size of a hole, or channel, through a carbon shell encapsulating a reservoir that contains material to be dispensed. The channel may be formed by irradiation with an electronbeam or other high-energy beam capable of focusing to a spot size less than about 5 nanom eters. In some embodiments, the dispensed droplet remains attached to the pipette by a small thread of material, an atomic …


Improving Core Skills In Apprentice Education, Peter Kenny Jul 2011

Improving Core Skills In Apprentice Education, Peter Kenny

Conference Papers

Many Motor trade apprentice students enter the later years of their studies ill prepared for the level of the material encountered. This is due to several factors including the level of mathematics they have on leaving school. A lot of basic material has been covered during earlier years of their training but by the time they reach the third year of their apprenticeship (Phase 6) it is not safe to assume that they have a full grasp of the basics required. I have developed a diagnostic test to measure the level of preparedness of these students. This test covers basic …


Aperture Coupled Patch Antenna Design Methods, Michael Civerolo, Dean Arakaki Jul 2011

Aperture Coupled Patch Antenna Design Methods, Michael Civerolo, Dean Arakaki

Electrical Engineering

Microstrip patch antennas have been used extensively in applications requiring low-profile, mounting structure conforming, and low-cost wireless communications. Feed methods (antenna-transmission line interface) are critical for optimum performance. The aperture coupled technique exhibits reduced transmission line radiation and enhanced antenna radiation and co- to cross-pol performance relative to microstrip and probe fed configurations. Researchers have focused on analytical methods and design improvements without identifying parametric tradeoffs or design methods. Hence, this paper presents theoretically and parametrically identified critical antenna dimensions and performance effects, and a design procedure to convert desired performance requirements into operational prototypes.


Attenuation In Extended Structures Coated With Thin Magneto-Dielectric Absorber Layer, Marina Koledintseva, Alexander G. Razmadze, Aleksandr Yakubovich Gafarov, Victor Khilkevich, James L. Drewniak, Takanori Tsutaoka Jul 2011

Attenuation In Extended Structures Coated With Thin Magneto-Dielectric Absorber Layer, Marina Koledintseva, Alexander G. Razmadze, Aleksandr Yakubovich Gafarov, Victor Khilkevich, James L. Drewniak, Takanori Tsutaoka

Electrical and Computer Engineering Faculty Research & Creative Works

Thin absorbing layers containing magnetic alloy or ferrite inclusions can be effectively used for attenuating common-mode currents on extended structures, such as power cords, cables, or edge-coupled microstrip lines. An analytical model to evaluate attenuation on the coaxial line with the central conductor coated with a magneto-dielectric layer is proposed and validated by the experiments and numerical modeling. The analytical model is validated using available magneto-dielectric samples of different thicknesses. This model can serve for comparing and predicting the absorptive properties of different samples of magneto-dielectric materials, whose compositions may be unknown, but dielectric and magnetic properties can be determined …


Synthesis And Characterization Of Cdse-Zns Core-Shell Quantum Dots For Increased Quantum Yield, Joshua James Angell Jul 2011

Synthesis And Characterization Of Cdse-Zns Core-Shell Quantum Dots For Increased Quantum Yield, Joshua James Angell

Master's Theses

Quantum dots are semiconductor nanocrystals that have tunable emission through changes in their size. Producing bright, efficient quantum dots with stable fluorescence is important for using them in applications in lighting, photovoltaics, and biological imaging. This study aimed to optimize the process for coating CdSe quantum dots (which are colloidally suspended in octadecene) with a ZnS shell through the pyrolysis of organometallic precursors to increase their fluorescence and stability. This process was optimized by determining the ZnS shell thickness between 0.53 and 5.47 monolayers and the Zn:S ratio in the precursor solution between 0.23:1 and 1.6:1 that maximized the relative …


Fourier Finite Element Analysis Of Laterally Loaded Piles In Elastic Media Internal Geotechnical Report 2011-1, William Higgins, Dipanjan Basu Jul 2011

Fourier Finite Element Analysis Of Laterally Loaded Piles In Elastic Media Internal Geotechnical Report 2011-1, William Higgins, Dipanjan Basu

Technical Reports

Laterally loaded piles are analyzed using the Fourier finite element method. Pile response was observed to be a function of the relative stiffness of pile and soil and of the pile slenderness ratio. The analysis is mostly performed for piles embedded in elastic soil with constant and linearly varying modulus although the pile response in two-layer soil profiles is also investigated. Equations describing pile head deflection, rotation and maximum bending moment are proposed for flexible long piles and stubby rigid piles. The design equations were developed after plotting the pile responses as functions of pile-soil stiffness ratio and pile slenderness …


Sustainability In Geotechnical Engineering Internal Geotechnical Report 2011-2, Aditi Misra, Dipanjan Basu Jul 2011

Sustainability In Geotechnical Engineering Internal Geotechnical Report 2011-2, Aditi Misra, Dipanjan Basu

Technical Reports

The built environment serves as a dynamic interface through which the human society and the ecosystem interact and influence each other. Understanding this interdependence is key to understanding sustainability as it applies to civil engineering. There is a growing consensus that delivering a sustainable built environment starts with incorporating sustainability thoughts at the planning and design stages of a project. Geotechnical engineering is the most resource intensive of all the civil engineering disciplines and can significantly influence the sustainability of infrastructure development because of its early position in the construction process. In this report, a review is made of the …


Acuta Enews July 2011, Vol 40, No. 7 Jul 2011

Acuta Enews July 2011, Vol 40, No. 7

ACUTA Newsletters

ln This lssue

From the President: The "T" in ACUTA....... Joe Harrington, Boston College

Second Dues lnvoices Mailed

The Daily Grind: What's on Your Desk Today?.......... Mona Brennan-Cotes, Univ. of Western Ontario

Calling All Young Professionals Amy Burton, ACUTA Mgr., Membership Mkt. & Corp. Relations

"The Future of Voice Communications": Winter Journal Looking for Articles

Board Report..................Riny Ledgerwood, San Diego State Univ.

Share Your RFIs/RFPs

Good Question on the ACUTA Listserv

lnfo Links ......... Randy Hayes, Univ. of Northern lowa

Disaster Recovery Requires Lots of What-lfs.................... Gary Audin, Delphi, lnc.

ACUTA Fall Seminar in Boston

ACUTA Webinar: Transitioning to lPv6 …


Keeping Employees Alive And Well, Farman A. Moayed Jul 2011

Keeping Employees Alive And Well, Farman A. Moayed

Department of Built Environment

No abstract provided.


Theoretical Explanation Of Bernstein Polynomials' Efficiency: They Are Optimal Combination Of Optimal Endpoint-Related Functions, Jaime Nava, Vladik Kreinovich Jul 2011

Theoretical Explanation Of Bernstein Polynomials' Efficiency: They Are Optimal Combination Of Optimal Endpoint-Related Functions, Jaime Nava, Vladik Kreinovich

Departmental Technical Reports (CS)

In many applications of interval computations, it turned out to be beneficial to represent polynomials on a given interval [x-, x+] as linear combinations of Bernstein polynomials (x- x - )k * (x+ - x)n-k. In this paper, we provide a theoretical explanation for this empirical success: namely, we show that under reasonable optimality criteria, Bernstein polynomials can be uniquely determined from the requirement that they are optimal combinations of optimal polynomials corresponding to the interval's endpoints.


The Occurrence Of False Positive Tests For Gunshot Residue Based On Simulations Of The Suspect's Occupation, Christopher R. Dockery, Matthew B. Rosenberg, Kimberly Kammerdiener, Lauren E. Mcadams Jul 2011

The Occurrence Of False Positive Tests For Gunshot Residue Based On Simulations Of The Suspect's Occupation, Christopher R. Dockery, Matthew B. Rosenberg, Kimberly Kammerdiener, Lauren E. Mcadams

Faculty Articles

Samples collected from high-risk occupations, or simulations thereof, are analyzed for elemental composition using laser-induced breakdown spectroscopy (LlBS) to determine the occurrence of false positive gunshot residue results generated in the work environment. Previous work involving the study of lifetime of detectable amounts of gunshot residue on the hands of a suspect shooter found that gunshot residue exists up to 5.27 days after a firearm discharge. However, certain environmental and/or occupational false positive tests for gunshot residue could result when sampling non-shooters. Samples collected from occupations or simulations thereof include welding, pyrotechnics, key cutting, mechanics, and paper products all of …


An Investigation Of Data Protection And Computer Security In Small Irish Medical Practices, Sean Mcgrath Jul 2011

An Investigation Of Data Protection And Computer Security In Small Irish Medical Practices, Sean Mcgrath

Dissertations

Small medical practices store and process the health information of their patients in order to aid in providing care to them. Because of this a level of trust exists between the patients and the practice to ensure the sensitive medical data is kept private and secure. There was no formalised way to test if this trust was well deserved and what level of protection was applied to such sensitive health records. A security model that is applicable to small medical practices for the purpose of protecting and securing the personal health information they store was constructed and validated by a …


Super-Resolution For Imagery From Integrated Microgrid Polarimeters, Russell C. Hardie, Daniel A. Lemaster, Bradley M. Ratliff Jul 2011

Super-Resolution For Imagery From Integrated Microgrid Polarimeters, Russell C. Hardie, Daniel A. Lemaster, Bradley M. Ratliff

Electrical and Computer Engineering Faculty Publications

Imagery from microgrid polarimeters is obtained by using a mosaic of pixel-wise micropolarizers on a focal plane array (FPA). Each distinct polarization image is obtained by subsampling the full FPA image. Thus, the effective pixel pitch for each polarization channel is increased and the sampling frequency is decreased. As a result, aliasing artifacts from such undersampling can corrupt the true polarization content of the scene. Here we present the first multi-channel multi-frame super-resolution (SR) algorithms designed specifically for the problem of image restoration in microgrid polarization imagers. These SR algorithms can be used to address aliasing and other degradations, without …


Why Neural Networks Are Computationally Efficient Approximators: An Explanation, Jaime Nava, Vladik Kreinovich Jul 2011

Towards Fast And Accurate Algorithms For Processing Fuzzy Data: Interval Computations Revisited, Gang Xiang, Vladik Kreinovich Jul 2011

A Slurry Consolidation Approach To Reconstitute Low-Plasticity Silt Specimens For Laboratory Triaxial Testing, Shuying Wang, Ronaldo Luna, Richard Wesley Stephenson Jul 2011

A Slurry Consolidation Approach To Reconstitute Low-Plasticity Silt Specimens For Laboratory Triaxial Testing, Shuying Wang, Ronaldo Luna, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Silt Specimen Reconstitution using a Slurry Consolidation Approach is Commonly Used for Laboratory Testing. This Paper Presents a New Slurry Consolidation Approach to Reconstitute Silt Specimens for Use in Triaxial Testing. Silt Specimens Were Reconstituted in a Split Vacuum Mold Mounted on a Special Experimental Setup. the Uniformity of the Reconstituted Specimens Was Verified by Measuring the Water Content and Grain Size Distribution throughout the Specimens. the Testing Program Was Expedited using a Special Sample Handling Technique to Move the Specimen from the Special Experimental Setup to the Triaxial Chamber Base Platen. the Handling Process Did Not Disturb the Specimens …


Climate Change Impacts: An Assessment For Water Resources Planning And Management In The Pacific Northwest Of The U.S, Venkataramana Sridhar, Xin Jin Jul 2011

Climate Change Impacts: An Assessment For Water Resources Planning And Management In The Pacific Northwest Of The U.S, Venkataramana Sridhar, Xin Jin

Civil Engineering Faculty Publications and Presentations

Assessing the hydrological impacts of climate change in the Pacific Northwest (PNW) region of the United States is important. Many global circulation models (GCMs) have a wide range of temperature and precipitation predictions for the PNW region (Bureau of Reclamation, 2011). Numerous studies have reported that decreasing snow pack, increasing temperatures and decreasing streamflow for many basins. For instance, Mote (2003) indicates that annual average temperatures in the Northwest rose faster than the global average during the 20th century. This warming occurred mostly during the winter and spring. The predominance of winter and spring warming, especially in regard to extreme …


Blair Balden, Margaret Von Steinen Jul 2011

Blair Balden, Margaret Von Steinen

International Faculty Researchers

A visiting professorship at the University of Passau in Passau, Germany for Dr. Blair Balden, a WMU associate professor of aviation, provided an excellent opportunity to share ideas and information about teaching aviation law with professors from Germany and Austria.


Comparison Of A High Purity Germanium Gamma Ray Spectrometer And A Multidimensional Nai(T1) Scintillation Gamma Ray Spectrometer, Greg Stratton Jul 2011

Comparison Of A High Purity Germanium Gamma Ray Spectrometer And A Multidimensional Nai(T1) Scintillation Gamma Ray Spectrometer, Greg Stratton

Aerospace Engineering

This report compares two different gamma ray spectrometers in terms of performance, operation, and apparatus and also investigates the design and integration challenges of using gamma ray spectrometers in space. The first spectrometer is a one-dimensional high purity germanium (HPGe) spectrometer and the second is a multidimensional NaI(Tl) scintillation spectrometer (MGRS). The key results show that the HPGe exhibits 15 to 27 times better energy resolution than the MGRS, but the MGRS is 52 times more sensitive and removes 177 % more of the background radiation.


3d Cfd On An Open Wheel Race Car Front Wing In Ground Effects, Thomas A. Price Jul 2011

3d Cfd On An Open Wheel Race Car Front Wing In Ground Effects, Thomas A. Price

Aerospace Engineering

The purpose of the report is to investigate the ability of the Fluent 6.3 k-ε Realizable turbulence model with standard wall functions to model the flow around the front wing of Cal Poly’s 2008 Formula SAE car. The three primary areas of interest are ground effects, the wing wheel interaction, and the wing tip vortices. Fluent was successful at modeling the increase suction from the ground effects, and the upwash due to the wing tip vortices. The results also displayed how the high pressure region in front of the tire propagates forward and interacts with the pressure distribution around the …


Dynamics Of Oxidized And Reduced Iron In A Northern Hardwood Forest, Colin B. Fuss, Charles T. Driscoll, Chris E. Johnson, Robert J. Petras, Timothy J. Fahey Jul 2011

Dynamics Of Oxidized And Reduced Iron In A Northern Hardwood Forest, Colin B. Fuss, Charles T. Driscoll, Chris E. Johnson, Robert J. Petras, Timothy J. Fahey

Civil and Environmental Engineering - All Scholarship

Iron (Fe) is ubiquitous in forest ecosystems and its cycle is thought to influence the development of soil, particularly Spodosols (podsolization), and the biogeochemistry of macronutrients such as carbon (C), nitrogen (N), and phosphorus (P), as well as many trace metals. The cycle of Fe in northern hardwood forests remains poorly understood. To address some of these uncertainties, we constructed a biogeochemical budget of Fe for a small catchment at the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, USA. Horizonal, temporal, and elevational patterns of concentrations and fluxes of oxidized and reduced Fe species were assessed …