Engineering Commons^™

Coherent Electron Transport By Adiabatic Passage In An Imperfect Donor Chain, Rajib Rahman, Richard P. Muller, James E. Levy, Malcolm S. Carroll, Gerhard Klimeck, Andrew D. Greentree, Lloyd C. L. Hollenberg

Birck and NCN Publications

Coherent Tunneling Adiabatic Passage (CTAP) has been proposed as a long-range physical qubit transport mechanism in solid-state quantum computing architectures. Although the mechanism can be implemented in either a chain of quantum dots or donors, a 1D chain of donors in Si is of particular interest due to the natural confining potential of donors that can in principle help reduce the gate densities in solid-state quantum computing architectures. Using detailed atomistic modeling, we investigate CTAP in a more realistic triple donor system in the presence of inevitable fabrication imperfections. In particular, we investigate how an adiabatic pathway for CTAP is …

Uncertainty Quantification Study For A Comprehensive Electrostatic Mems Switch Model, Michael G. Snow, Anil K. Bajaj

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

This work presents an uncertainty analysis of a comprehensive model for an electrostatic MEMS switch. The goal is to elucidate the effects of parameter variations on certain performance characteristics. A sufficiently detailed model of an electrostatically actuated beam is developed. This model accounts for various physical effects, including the electrostatic fringing field, finite length of electrodes, squeeze film damping, and contact between the beam and the dielectric layer. The performance characteristics of immediate interest are the static and dynamic pull-in voltages for switch. Using Latin Hypercube and other sampling methods, the model is evaluated to find these performances characteristics when …

A Synthesis Of Overweight Truck Permitting, Muhammad K. Bilal, Muhammad Irfan, Anwaar Ahmed, Samuel Labi, Kumares C. Sinha

JTRP Technical Reports

For purposes of safety and system preservation, trucking operational characteristics are regulated through legislation and policies. However, special permits are granted for trucks to exceed specified operational restrictions. Thus, the Indiana DOT not only seeks highway operations policies that retain/attract heavy industry including those that haul large loads but also seeks to protect the billions of taxpayer dollars invested in highway infrastructure. As such, it is sought to avoid policies that may lead to premature and accelerated deterioration of assets through excess loading or undue safety hazard through oversize loads. This study was carried out primarily to document the state …

Refine Process To Identify, Evaluate, And Adopt New Technologies And Identify New Proven Technologies For Indiana, Joseph V. Sinfield

JTRP Technical Reports

No abstract provided.

Determination Of Unit Hydrograph Parameters For Indiana Watersheds, Jared L. Wilkerson, Venkatesh M. Merwade

JTRP Technical Reports

Regression equations predicting Clark Synthetic Unit Hydrograph (SUH) parameters for time of concentration (tc) and storage coefficient (R) are developed for small watersheds across Indiana [drainage areas = 3-38 square miles (mi2)]. The state is partitioned into three regions: North, Central, and South, with consideration for past regionalization studies of Indiana and geomorphology. The equations are derived using multiple linear regression analysis for 30 watersheds with 90 observed rainfall-runoff events. Clark SUH parameters are optimized using Hec-HMS to match the observed rainfall-runoff events. The optimized Clark SUH parameters are related to geomorphologic parameters estimated using geographic information system (GIS) applications. …

Comprehensive Reduced-Order Models Of Electrostatically Actuated Mems Switches And Their Dynamics Including Impact And Bounce, Michael G. Snow, Anil K. Bajaj

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

As MEMS technology develops it is becoming better understood that MEMS designers must account for the large uncertainties characteristic of the relevant manufacturing processes. Uncertainty quantification tasks the designer with evaluating many different possible outcomes from the manufacturing process which creates a demand for models that are accurate and comprehensive, yet fast to evaluate. This work presents a comprehensive reduced-order model of electrostatically actuated switches incorporating a range of effects that are typically included only in FE modeling codes. Specifically, the model accounts for variable electrode geometry, stretching of centerline or large displacement effects, fringing field, squeeze film and rarefied …

Simulation Of Sub-Micron Thermal Transport In A Mosfet Using A, James Loy, Druv Singh, Jayathi Y. Murthy

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

Self-heating has emerged as a critical bottleneck to scaling in modern transistors. In simulating heat conduction in these devices, it is important to account for the granularity of phonon transport since electron-phonon scattering occurs preferentially to select phonon groups. However, a complete accounting for phonon dispersion, polarization and scattering is very expensive if the Boltzmann transport equation (BTE) is used. Moreover, difficulties with convergence are encountered when the phonon Knudsen number becomes small. In this paper we simulate a two-dimensional bulk MOSFET hotspot problem using a partially-implicit hybrid BTE-Fourier solver which is significantly less expensive than a full BTE solution, …

Eight-Channel Reconfigurable Microring Filters With Tunable Frequency, Extinction Ratio And Bandwidth, Hao Shen, Maroof H. Khan, Li Fan, Lin Zhao, Yi Xuan, Jing Ouyang, Leo T. Varghese, Minghao Qi

Birck and NCN Publications

We demonstrate an eight-channel reconfigurable optical filter on a silicon chip. It consists of cascaded microring resonators and integrated compact heaters. With an embedded Mach-Zehnder (MZ) arm coupling to a microring resonator, the important parameters of a filter such as center frequency, extinction ratio and bandwidth can be controlled simultaneously for purposes of filtering, routing and spectral shaping. Thus our device could potentially be useful in dense wavelength division multiplexing (DWDM) and radio frequency arbitrary waveform generation (RFAWG). Multichannel filter response was successfully tuned to match the International Telecommunication Unit (ITU) grid with 50, 100 and 200GHz in channel spacing. …

Acoustic Phonon Scattering In Bi2te3/Sb2te3 Superlattices, Yaguo Wang, Carl Liebig, Xianfan Xu, Rama Venkatasubramanian

Birck and NCN Publications

Ultrafast time-resolved measurements were conducted to investigate long-wavelength acoustic phonon scattering and velocity reduction in Bi2Te3/Sb2Te3 superlattices. We show that both these phenomena suppress heat transfer process, with the phonon scattering contributing more in differentiating the lattice thermal conductivities among films with different periods. Measurements of reduction in the acoustic phonon amplitudes support the decrease in the thermal conductivity for certain superlattice periods, which is not predicted by acoustic mismatch theory. This study is a direct measurement of coherent acoustic phonons in superlattices which is of significant interest to thermoelectrics.

Iii-Nitride Nanopyramid Light Emitting Diodes Grown By Organometallic Vapor Phase Epitaxy, Isaac Wildeson, Robert Colby, David Ewoldt, Zhiwen Liang, Dmitri Zakharov, Nestor J. Zaluzec, R. Edwin García, E A. Stach, Timothy D. Sands

Birck and NCN Publications

Nanopyramid light emitting diodes (LEDs) have been synthesized by selective area organometallic vapor phase epitaxy. Self-organized porous anodic alumina is used to pattern the dielectric growth e templates via reactive ion etching, eliminating the need for lithographic processes. (In,Ga)N quantum well growth occurs primarily on the six {1 (1) over bar 01} semipolar facets of each of the nanopyramids, while coherent (In,Ga)N quantum dots with heights of up to similar to 20 nm are incorporated at the apex by controlling growth conditions. Transmission electron microscopy (TEM) indicates that the (In,Ga)N active regions of the nanopyramid heterostructures are completely dislocation-free. Temperature-dependent …

Metric Signature Transitions In Optical Metamaterials, Igor Smolyaninov, Evgenii Narimanov

Birck and NCN Publications

We demonstrate that the extraordinary waves in indefinite metamaterials experience an (- - + +) effective metric signature. During a metric signature change transition in such a metamaterial, a Minkowski space-time is created together with a large number of particles populating the space-time. Such metamaterial models provide a tabletop realization of metric signature change events suggested to occur in Bose-Einstein condensates and quantum gravity theories.

Evaluation Of Toxicity Analysis For Foundry Sand Specifications, M. Katherine Banks, A. Paul Schwab

JTRP Technical Reports

Byproducts from many industries have the potential to be used as construction materials, but some means is required to determine if the material is environmentally benign. Foundry sands are produced in many states and can be useful as in transportation projects. However, INDOT currently requires the use of the MICROTOX test to assess the potential toxicity of the sands, and this requirement is viewed as an unnecessary impediment by the producers of foundry sands and is a requirement not encountered in other states. Therefore, the goal of this project was to review current requirements for testing of recycled materials, determine …

Microcantilever Dynamics In Liquid Environment Dynamic Atomic Force Microscopy When Using Higher-Order Cantilever Eigenmodes, Daniel Kiracofe, Arvind Raman

Birck and NCN Publications

Dynamic atomic force microscopy is currently evolving from a single to a multifrequency instrument for nanoscale imaging often employing higher-order microcantilever eigenmodes for improved resolution and force spectroscopy. In this work the authors study the fundamentals of cantilever dynamics and energy dissipation when soft cantilevers are driven at their second flexural eigenmode and interact with samples in liquid environments. Contrary to the conventional first eigenmode operation, second eigenmode operation in liquids is often dominated by a subharmonic response (e.g., one tap every four drive cycles) and there is an energy transfer to the first eigenmode creating a new channel of …

Current Density And Continuity In Discretized Models, Timothy B. Boykin, Mathieu Luisier, Gerhard Klimeck

Birck and NCN Publications

Discrete approaches have long been used in numerical modelling of physical systems in both research and teaching. Discrete versions of the Schr ¨ odinger equation employing either one or several basis functions per mesh point are often used by senior undergraduates and beginning graduate students in computational physics projects. In studying discrete models, students can encounter conceptual difficulties with the representation of the current and its divergence because different finite-difference expressions, all of which reduce to the current density in the continuous limit, measure different physical quantities. Understanding these different discrete currents is essential and requires a careful analysis of …

Effect Of Relative Density And Stress Level On The Bearing Capacity Of Footings On Sand, D Loukidis, Rodrigo Salgado

Lyles School of Civil Engineering Faculty Publications

The design of shallow foundations relies on bearing capacity values calculated using empirical procedures that are based in part on solutions obtained using the method of characteristics, which assumes a soil that is perfectly plastic following an associated flow rule. In this paper the problem of strip and circular footings resting on the surface of a sand layer is analysed using the finite-element method. Analyses are performed using a two-surface plasticity constitutive model that realistically captures the aspects of the mechanical response of sands that are relevant to the bearing capacity problem. In particular, the model accounts for non-associated flow, …

Knudsen Force Modeling In Application To Microsystems, Jeremy S. Nabeth, Sruti Chigullapalli, Alina A. Alexeenko

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

At the microscale, even moderate temperature differences can result in significant Knudsen forces generated by the energy exchange between gas molecules and solids immersed in a gas. Creating, controlling and measuring Knudsen forces in microsystems can be an arduous task since only limited theory exists at present. This present study investigates the mechanism of Knudsen forces in detail based on numerical solution of the Boltzmann kinetic equation. The Knudsen force is shown, in general, to be a result of thermal nonequilibrium between gas and solid. The simulations are validated by comparison with experimental measurements that have been reported by Passian …

What Determines Knudsen Force At The Microscale, Jeremy S. Nabeth, Sruti Chigullapalli, Alina A. Alexeenko

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

Knudsen forces arise in microscale systems when there is a thermal gradient with a characteristic length scale comparable to the molecular mean free path of the ambient gas. These forces are sometimes referred as radiometric or thermo-molecular forces [1] and have been recently measured experimentally in a microscale configuration using heated atomic force microscopy (AFM) probes [2]. The Knudsen force on microstructures with thermal gradients can provide a novel actuation mechanism for mass detection, thermogravimetry, and very high-resolution heat flux measurements. While measuring such forces precisely at microscale can be an arduous task especially since only limited analytical results exist, …

High Performance Atomic-Layer-Deposited Laluo3/Ge-On-Insulator P-Channel Metal-Oxide-Semiconductor Field-Effect Transistor With Thermally Grown Geo2 As Interfacial Passivation Layer, J J. Gu, Y Q. Liu, M Xu, G K. Celler, R G. Gordon, P. D. Ye

Birck and NCN Publications

Enhancement-mode p-channel metal-oxide-semiconductor field-effect transistor (MOSFET) on germanium-on-insulator substrate is fabricated with atomic-layer-deposited (ALD) LaLuO3 as gate dielectric. Significant improvement in both on-state current and effective hole mobility has been observed for devices with thermal GeO2 passivation. The negative threshold voltage (V-T) shift in devices with GeO2 interfacial layer (IL) further demonstrates the effectiveness of surface passivation. Results from low temperature mobility characterization show that phonon scattering is the dominant scattering mechanism at a large inversion charge, indicating good interface quality. The combination of higher-k LaLuO3 and ultrathin GeO2 IL is a promising solution to the tradeoff between the aggressive …

Fatigue Strength Of Steel Bridge Members With Intersecting Welds, David T. Delong, Mark D. Bowman

JTRP Technical Reports

The brittle fracture of the Hoan Bridge in December 2000 highlighted the fracture susceptibility of details containing intersecting welds in steel bridges. Though it is now known that details with intersecting welds should be avoided, many existing bridges in Indiana contain details with intersecting welds. Little experimental data on the fatigue performance of these details exists.

The purpose of this study was to evaluate the fatigue strength of several details commonly found in steel bridges in Indiana that contain intersecting welds. Large-scale experimental fatigue testing were performed using nine steel beams to study the behavior of three basic types of …

Snow And Ice Removal And Anti-Icing Synthesis Study, Bob Mccullouch

JTRP Technical Reports

No abstract provided.

Proposed Implementation Of The Indiana Erosion And Sediment Control Field Guide, Lynn A. Corson

JTRP Technical Reports

No abstract provided.

Synthesis Study: Development Of An Electronic Detection And Warning System To Prevent Overheight Vehicles From Impacting Overhead Bridges, Joseph V. Sinfield

JTRP Technical Reports

Overheight vehicle impacts with bridges are surprisingly common. The damage from collisions can range from minor to severe, and there is also evidence that some bridges are impacted multiple times, leading to the potential for cumulative damage effects. Thus there is a clear need to attempt to prevent overheight vehicle collisions with bridges.

This Synthesis Study provides a review of solutions that exist to detect and forewarn overheight vehicles and thereby prevent a collision, and specifically examines the breadth of available overheight vehicle detection technologies, the commercial availability of such equipment, and the experience of relevant DOTs with installed and …

Numerical Approach For Quantification Of Epistemic Uncertainty, John Jakeman, Michael Eldred, Dongbin Xiu

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

In the field of uncertainty quantification, uncertainty in the governing equations may assume two forms: aleatory uncertainty and epistemic uncertainty. Aleatory uncertainty can be characterised by known probability distributions whilst epistemic uncertainty arises from a lack of knowledge of probabilistic information. While extensive research efforts have been devoted to the numerical treatment of aleatory uncertainty, little attention has been given to the quantification of epistemic uncertainty. In this paper, we propose a numerical framework for quantification of epistemic uncertainty. The proposed methodology does not require any probabilistic information on uncertain input parameters. The method only necessitates an estimate of the …

Puremd Manual (Purdue Reactive Molecular Dynamics Program), Hasan Metin Aktulga

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

No abstract provided.

Strain Rate Sensitivity Of Nanocrystalline Au Films At Room Temperature, K Jonnalagadda, N Karanjgaokar, Joo Lien Chee, Dimitrios Peroulis

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

The effect of strain rate on the inelastic properties of nanocrystalline Au films was quantified with 0.85 and 1.76 lm free-standing microscale tension specimens tested over eight decades of strain rate, between 6 106 and 20 s1. The elastic modulus was independent of the strain rate, 66 ± 4.5 GPa, but the inelastic mechanical response was clearly rate sensitive. The yield strength and the ultimate tensile strength increased with the strain rate in the ranges 575–895 MPa and 675–940 MPa, respectively, with the yield strength reaching the tensile strength at strain rates faster than 101 s1. The activation volumes for …

Table 6.04, Mark E. Shaurette

Supplementary Content for <em>Demolition: Practices, Technology, and Management</em> <br>(ISBN 978-1-55753-567-2)

No abstract provided.

On The Bandstructure Velocity And Ballistic Current Of Ultra-Narrow Silicon Nanowire Transistors As A Function Of Cross Section Size, Orientation, And Bias, Neophytos Neophytou, Sung-Geun Kim, Gerhard Klimeck, Hans Kosina

Birck and NCN Publications

A 20 band sp(3)d(5)s* spin-orbit-coupled, semiempirical, atomistic tight-binding model is used with a semiclassical, ballistic field-effect-transistor model, to theoretically examine the bandstructure carrier velocity and ballistic current in silicon nanowire (NW) transistors. Infinitely long, uniform, cylindrical, and rectangular NWs, of cross sectional diameters/sides ranging from 3-12 nm are considered. For a comprehensive analysis, n-type and p-type metal-oxide semiconductor (NMOS and PMOS) NWs in [100], [110], and [111] transport orientations are examined. In general, physical cross section reduction increases velocities, either by lifting the heavy mass valleys or significantly changing the curvature of the bands. The carrier velocities of PMOS [110] …

The Impact Of Nonlinearity On Degenerate Parametric Amplifiers, Jeff Rhoads, Steven W. Shaw

Birck and NCN Publications

This work investigates the effects of system nonlinearities on degenerate parametric amplifiers. A simple, Duffing-type nonlinearity is appended to a representative equation of motion for a mechanical or electromechanical parametric amplifier, and classical perturbation methods are used to characterize the resulting effects on the amplifier's frequency response and performance. Ultimately, the work demonstrates that parametric amplification can be realized in nonlinear, dynamic-range limited systems, such as resonant micro-or nanosystems, but at the expense of performance degradation. Additionally, it is shown that nonlinear amplifiers can be operated above their linear instability threshold but that doing so results in bistable amplified responses.

Ambipolar Graphene Field Effect Transistors By Local Metal Side Gates, J F. Tian, L A. Jauregui, G Lopez, H Cao, Yong P. Chen

Birck and NCN Publications

We demonstrate ambipolar graphene field effect transistors individually controlled by local metal side gates. The side gated field effect can have on/off ratio comparable with that of the global back gate, and can be tuned in a large range by the back gate and/or a second side gate. We also find that the side gated field effect is significantly stronger by electrically floating the back gate compared to grounding the back gate, consistent with the finding from electrostatic simulation.

Nanoscale Metal-Metal Contact Physics From Molecular Dynamics: The Strongest Contact Size, Hojin Kim, Alejandro Strachan

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

Using molecular dynamics we find that the tensile strength of the contacts between two clean platinum surfaces with nanoscale asperities is strongly size dependent with a maximum strength for contact lengths of approximately 5 nm. This is the first time a strongest size is observed in single crystals. The strengthening with decreasing size down to 5 nm results from a decrease in the initial density of mobile dislocations available for plastic deformation and the subsequent weakening originates from a reduction in the constraint to mechanical deformation inside the contact by the bulk.