Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 181 - 200 of 200

Full-Text Articles in Engineering

Operation Of A Dna-Based Autocatalytic Network In Serum, Elton Graugnard, Amber Cox, Jeunghoon Lee, Cheryl Jorcyk, Bernard Yurke, William L. Hughes Jan 2011

Operation Of A Dna-Based Autocatalytic Network In Serum, Elton Graugnard, Amber Cox, Jeunghoon Lee, Cheryl Jorcyk, Bernard Yurke, William L. Hughes

Materials Science and Engineering Faculty Publications and Presentations

The potential for inferring the presence of cancer by the detection of miRNA in human blood has motivated research into the design and operation of DNA-based chemical amplifiers that can operate in bodily fluids. As a first step toward this goal, we have tested the operation of a DNA-based autocatalytic network in human serum and mouse serum. With the addition of sodium dodecyl sulfate to prevent degradation by nuclease activity, the network was found to operate successfully with both DNA and RNA catalysts.


A Comparison Of Two Engineering Outreach Programs For Adolescents, Louis S. Nadelson, Janet M. Callahan Jan 2011

A Comparison Of Two Engineering Outreach Programs For Adolescents, Louis S. Nadelson, Janet M. Callahan

Materials Science and Engineering Faculty Publications and Presentations

There is continued growth and development of outreach programs designed to increase pre-college students’ awareness and understanding of engineering as a profession and as a career. These outreach programs vary in format and in the groups targeted for participation but maintain the same fundamental goal of increasing participant knowledge of engineering. Many of these outreach programs also maintain the implicit goal of increasing the participants' knowledge and attitudes toward college. The additional resources and funding that are commonly allocated to support outreach programs frequently involve documenting accountability which motivates evaluation of program impact. Therefore, many outreach events include program evaluation …


Programmable Periodicity Of Quantum Dot Arrays With Dna Origami Nanotubes, Hieu Bui, Craig Onodera, Carson Kidwell, Yerpeng Tan, Elton Graugnard, Wan Kuang, Jeunghoon Lee, William B. Knowlton, Bernard Yurke, William L. Hughes Sep 2010

Programmable Periodicity Of Quantum Dot Arrays With Dna Origami Nanotubes, Hieu Bui, Craig Onodera, Carson Kidwell, Yerpeng Tan, Elton Graugnard, Wan Kuang, Jeunghoon Lee, William B. Knowlton, Bernard Yurke, William L. Hughes

Materials Science and Engineering Faculty Publications and Presentations

To fabricate quantum dot arrays with programmable periodicity, functionalized DNA origami nanotubes were developed. Selected DNA staple strands were biotin-labeled to form periodic binding sites for streptavidin-conjugated quantum dots. Successful formation of arrays with periods of 43 and 71 nm demonstrates precise, programmable, large-scale nanoparticle patterning; however, limitations in array periodicity were also observed. Statistical analysis of AFM images revealed evidence for steric hindrance or site bridging that limited the minimum array periodicity.


Kinetics Of Dna And Rna Hybridization In Serum And Serum-Sds, Elton Graugnard, Amber Cox, Jeunghoon Lee, Cheryl Jorcyk, Bernard Yurke, William L. Hughes Sep 2010

Kinetics Of Dna And Rna Hybridization In Serum And Serum-Sds, Elton Graugnard, Amber Cox, Jeunghoon Lee, Cheryl Jorcyk, Bernard Yurke, William L. Hughes

Materials Science and Engineering Faculty Publications and Presentations

Cancer is recognized as a serious health challenge both in the United States and throughout the world. While early detection and diagnosis of cancer leads to decreased mortality rates, current screening methods require significant time and costly equipment. Recently, increased levels of certain micro-ribonucleic acids (miRNAs) in the blood have been linked to the presence of cancer. While blood-based biomarkers have been used for years in cancer detection, studies analyzing trace amounts of miRNAs in blood and serum samples are just the beginning. Recent developments in deoxyribonucleic acid (DNA) nanotechnology and DNA computing have shown that it is possible to …


Limitations Of Poole–Frenkel Conduction In Bilayer Hfo2/Sio2 Mos Devices, Richard G. Southwick Iii, Justin Reed, Christopher Buu, Ross Butler, Gennadi Bersuker, William B. Knowlton Jun 2010

Limitations Of Poole–Frenkel Conduction In Bilayer Hfo2/Sio2 Mos Devices, Richard G. Southwick Iii, Justin Reed, Christopher Buu, Ross Butler, Gennadi Bersuker, William B. Knowlton

Materials Science and Engineering Faculty Publications and Presentations

The gate leakage current of metal–oxide– semiconductors (MOSs) composed of hafnium oxide (HfO2) exhibits temperature dependence, which is usually attributed to the standard Poole–Frenkel (P–F) transport model. However, the reported magnitudes of the trap barrier height vary significantly. This paper explores the fundamental challenges associated with applying the P–F model to describe transport in HfO2/SiO2 bilayers in n/p MOS field-effect transistors composed of 3- and 5-nm HfO2 on 1.1-nm SiO2 dielectric stacks. The extracted P–F trap barrier height is shown to be dependent on several variables including the following: the temperature range, method …


Recent Advances In High Density Area Array Interconnect Bonding For 3d Integration, J. M. Lannon, J., C. Gregory, M. Lueck, A. Huffman, D. Temple, Amy J. Moll, William B. Knowlton Apr 2010

Recent Advances In High Density Area Array Interconnect Bonding For 3d Integration, J. M. Lannon, J., C. Gregory, M. Lueck, A. Huffman, D. Temple, Amy J. Moll, William B. Knowlton

Materials Science and Engineering Faculty Publications and Presentations

The demand for more complex and multifunctional micro systems with enhanced performance characteristics for military applications is driving the electronics industry toward the use of best-of-breed materials and device technologies. Threedimensional (3-D) integration provides a way to build complex microsystems through bonding and interconnection of individually optimized device layers without compromising system performance and fabrication yield. Bonding of device layers can be achieved through polymer bonding or metal-metal interconnect bonding with a number of metalmetal systems. RTI has been investigating and characterizing Cu-Cu and CulSn-Cu processes for high density area array imaging applications, demonstrating high yield bonding between sub-I5 11m …


Effects Of Crystallographic Orientation On The Early Stages Of Oxidation In Nickel And Chromium, Louis P. Bonfrisco, Megan Frary Mar 2010

Effects Of Crystallographic Orientation On The Early Stages Of Oxidation In Nickel And Chromium, Louis P. Bonfrisco, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Surface orientation plays an important role in the oxidation behavior of single crystals where studies have found the relative oxidation rates for surfaces with different orientations. However, most materials are polycrystalline and contain myriad orientations that contribute to the overall oxidation process. Here we determine the effects of orientation on the early stages of oxidation behavior as a function of surface orientation for polycrystalline nickel (face-centered cubic) and chromium (body-centered cubic). After high temperature oxidation, the oxide topography is characterized using optical profilometry and the underlying microstructure is characterized with electron backscatter diffraction (EBSD). By correlating results from EBSD and …


Microstructural Effects During Chemical Mechanical Planarization Of Copper, Patrick J. Andersen, Mariela N. Bentancur, Amy J. Moll, Megan Frary Jan 2010

Microstructural Effects During Chemical Mechanical Planarization Of Copper, Patrick J. Andersen, Mariela N. Bentancur, Amy J. Moll, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Novel die-stacking schema using through-wafer interconnects require vias to be filled with electroplated Cu, resulting in thick copper films, and requiring an aggressive first-step CMP. This work investigates the effects of microstructure on CMP of copper films, which are not presently well understood. Bulk and local removal rates were investigated for several different microstructures. Surface orientation maps were created and the orientations of individual grains were correlated with topographical data to elucidate local removal behavior. Cu removal depends on the details of the microstructure, and certain microstructures allowed for either faster or more uniform removal of thick Cu films.


Influence Of Grain Boundary Character On Creep Void Formation In Alloy 617, Thomas Lillo, James Cole, Megan Frary, Scott Schlegel Dec 2009

Influence Of Grain Boundary Character On Creep Void Formation In Alloy 617, Thomas Lillo, James Cole, Megan Frary, Scott Schlegel

Materials Science and Engineering Faculty Publications and Presentations

Alloy 617, a high temperature creep-resistant, nickel-based alloy, is being considered for the primary heat exchanger for the Next Generation Nuclear Plant (NGNP) which will operate at temperatures exceeding 760oC. Orientation imaging microscopy (OIM) is used to characterize the grain boundaries in the vicinity of creep voids that develop during high temperature creep tests (800-1000oC at creep stresses ranging from 20-85 MPa) terminated at creep strains ranging from 5-40%. Observations using optical microscopy indicate creep rate does not significantly influence the creep void fraction at a given creep strain. Preliminary analysis of the OIM data indicates …


Precipitate Redistribution During Creep Of Alloy 617, Scott Schlegel, Sharla Hopkins, E. Young, James Cole, Thomas Lillo, Megan Frary Dec 2009

Precipitate Redistribution During Creep Of Alloy 617, Scott Schlegel, Sharla Hopkins, E. Young, James Cole, Thomas Lillo, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Nickel-based superalloys are being considered for applications within advanced nuclear power generation systems due to their high temperature strength and corrosion resistance. Alloy 617, a candidate for use in heat exchangers, derives its strength from both solid solution strengthening and the precipitation of carbide particles. However, during creep, carbides that are supposed to retard grain boundary motion are found to dissolve and re-precipitate on boundaries in tension. To quantify the redistribution, we have used electron backscatter diffraction and energy dispersive spectroscopy to analyze the microstructure of 617 after creep testing at 900 and 1000°C. The data were analyzed with respect …


On The Thermal Activation Of Negative Bias Temperature Instability, Richard G. Southwick Iii, William B. Knowlton, Ben Kaczer, Tibor Grasser Oct 2009

On The Thermal Activation Of Negative Bias Temperature Instability, Richard G. Southwick Iii, William B. Knowlton, Ben Kaczer, Tibor Grasser

Materials Science and Engineering Faculty Publications and Presentations

The temperature dependence of negative bias temperature instability (NBTI) is investigated on 2.0nm SiO2 devices from temperatures ranging from 300K down to 6K with a measurement window of ~12ms to 100s. Results indicate that classic NBTI degradation is observed down to ~200K and rarely observed at temperatures below 140K in the experimental window. Since experimental results show the charge trapping component contributing to NBTI is thermally activated, the results cannot be explained with the conventionally employed elastic tunneling theory. A new mechanism is observed at temperatures below 200K where device performance during stress conditions improves rather than degrades with …


Effect Of Grain Boundary Engineering On Microstructural Stability During Annealing, Scott M. Schlegel, Sharla Hopkins, Megan Frary Jul 2009

Effect Of Grain Boundary Engineering On Microstructural Stability During Annealing, Scott M. Schlegel, Sharla Hopkins, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Grain boundary engineering, which increases the special boundary fraction, may improve microstructural stability during annealing. Different processing routes are undertaken to establish the effectiveness of each and to better understand which microstructural features determine the resulting stability. We find that multiple cycles of grain boundary engineering result in a material that resists abnormal grain growth better than other processing routes despite similarities in special boundary fraction, grain size, and general boundary connectivity among as-processed materials.


Enhancing Precalculus Curricula With E-Learning: Implementation And Assessment, Janet Callahan, Seung Youn Chyung, Joanna Guild, William Clement, Joe Guarino, Doug Bullock, Cheryl Schrader Jun 2008

Enhancing Precalculus Curricula With E-Learning: Implementation And Assessment, Janet Callahan, Seung Youn Chyung, Joanna Guild, William Clement, Joe Guarino, Doug Bullock, Cheryl Schrader

Materials Science and Engineering Faculty Publications and Presentations

During Fall semester of 2007, a semester-long, quasi-experimental study was conducted at Boise State University to investigate the effectiveness of a systematically sequenced and managed, self-paced e-learning activity on improving students’ academic performance and motivation. A total of 125 students enrolled in 3 different sections of a Precalculus class participated in the study. The e-learning activity was implemented in 2 of the 3 sections as a required homework assignment. Students enrolled in one of the 2 selected sections were all engineering majors. The 3rd section was a control group that did not use the e-learning activity. A pre-test, measuring …


Correlation-Space Description Of The Percolation Transition In Composite Microstructures, Megan E. Frary, Christopher A. Schuh Oct 2007

Correlation-Space Description Of The Percolation Transition In Composite Microstructures, Megan E. Frary, Christopher A. Schuh

Materials Science and Engineering Faculty Publications and Presentations

We explore the percolation threshold shift as short-range correlations are introduced and systematically varied in binary composites. Two complementary representations of the correlations are developed in terms of the distribution of phase bonds or, alternatively, using a set of appropriate short-range order parameters. In either case, systematic exploration of the correlation space reveals a boundary that separates percolating from nonpercolating structures and permits empirical equations that identify the location of the threshold for systems of arbitrary short-range correlation states. Two- and three-dimensional site lattices with two-body correlations, as well as a two-dimensional hexagonal bond network with three-body correlations, are explored. …


Simulation Of Plasticity In Nanocrystalline Silicon, M. J. Demkowicz, A. S. Argon, D. Farkas, Megan Frary Oct 2007

Simulation Of Plasticity In Nanocrystalline Silicon, M. J. Demkowicz, A. S. Argon, D. Farkas, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Molecular dynamics investigation of plasticity in a model nanocrystalline silicon system demonstrates that inelastic deformation localizes in intergranular regions. The carriers of plasticity in these regions are atomic environments that can be described as high-density liquid-like amorphous silicon. During fully developed flow, plasticity is confined to system-spanning intergranular zones of easy flow. As an active flow zone rotates out of the plane of maximum resolved shear stress during deformation to large strain, new zones of easy flow are formed. Compatibility of the microstructure is accommodated by processes such as grain rotation and formation of new grains. Nano-scale voids or cracks …


Determination Of Three-Dimensional Grain Boundary Connectivity From Two-Dimensional Microstructures, Megan Frary Aug 2007

Determination Of Three-Dimensional Grain Boundary Connectivity From Two-Dimensional Microstructures, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

The connectivity of so-called "special" and "general" grain boundaries at a quadruple node is known to be nonrandom as a result of crystallographic constraints. Although a quadruple node is a three-dimensional feature, there exist two-dimensional features which are topologically identical. Therefore, the distribution of these two-dimensional features may be used to determine the three-dimensional connectivity. Computer simulations of a three-dimensional microstructure which is virtually serial sectioned are used to validate the proposed approach.


Photonic Band Tuning In 2d Photonic Crystals By Atomic Layer Deposition, Elton Graugnard, Davy P. Gaillot, Simon N. Dunham, Curtis W. Neff, Tsuyoshi Yamashita, Christopher J. Summers Oct 2006

Photonic Band Tuning In 2d Photonic Crystals By Atomic Layer Deposition, Elton Graugnard, Davy P. Gaillot, Simon N. Dunham, Curtis W. Neff, Tsuyoshi Yamashita, Christopher J. Summers

Materials Science and Engineering Faculty Publications and Presentations

Atomic layer deposition (ALD) has become a powerful tool for the fabrication of high quality 3-dimentional photonic crystals (PCs) from both inorganic (opal) and organic (holographically patterned polymer) templates [1,2]. With ALD, highly conformal films can be grown with a precision of 0.05 nm, which, when combined with the availability of a wide range of low temperature film growth protocols, enables a high degree of control over material and structural properties to precisely tune optical properties [3]. Two-dimensional photonic crystals have been developed extensively for applications in optical interconnects, beam steering, and sensor devices; and are predominantly fabricated by electron-beam …


Between Microscopic And Mesoscopic Descriptions Of Twin-Twin Interaction, Peter Müllner Mar 2006

Between Microscopic And Mesoscopic Descriptions Of Twin-Twin Interaction, Peter Müllner

Materials Science and Engineering Faculty Publications and Presentations

On a microscopic scale, deformation twinning is carried by the motion of twinning disconnections. A disconnection is an interfacial line defect characterized by a Burgers vector, a line vector, and a step vector. The Burgers vector (dislocation component of the disconnection) carries the deformation while the step vector (ledge component) carries the transformation from one twin variant to the other. On a mesoscopic scale, the deformation produced by twinning is a simple shear. A moving disclination dipole provides a mesoscopic model accounting for the twinning shear. Twin – twin interaction processes including the intersection of twins, the formation of structured …


Correlations Beyond The Nearest-Neighbor Level In Grain Boundary Networks, C. A. Schuh, M. Frary Mar 2006

Correlations Beyond The Nearest-Neighbor Level In Grain Boundary Networks, C. A. Schuh, M. Frary

Materials Science and Engineering Faculty Publications and Presentations

Correlations among 'special' and 'general' grain boundaries are studied on two-dimensional networks, by examining the configurational entropy of boundary structures as well as percolation thresholds. Consideration of crystallographic constraints at various length scales reveals that higher-order constraints play a role in boundary connectivity and network structure. Implications for grain boundary engineering are discussed and directions for future work highlighted.


Low Temperature Co-Fired Ceramics For Micro-Fluidics, John Youngsman, Brian Marx, Martin Schimpf, Scott Wolter, Jeff Glass, Amy Moll Jan 2006

Low Temperature Co-Fired Ceramics For Micro-Fluidics, John Youngsman, Brian Marx, Martin Schimpf, Scott Wolter, Jeff Glass, Amy Moll

Materials Science and Engineering Faculty Publications and Presentations

The miniaturization of analytical instruments and packaging of novel sensors is an area that has attracted significant research interest and offers many opportunities for product commercialization. Low Temperature Co-fired Ceramics (LTCC) is a materials system composed of alumina and glass in an organic binder. LTCC is a good choice for sensor development because of the ease of incorporating features in the ‘green’ or unfired state such as electrical traces, fluidic pathways and passive electrical components. After a firing cycle, what remains is a robust, monolithic device with features embedded in the package. In order for LTCC to be a successful …