Engineering Commons^™

Nesting Forward-Mode Ad In A Functional Framework, Jeffrey M. Siskind, Barak A. Pearlmutter

Department of Electrical and Computer Engineering Technical Reports

We discuss the augmentation of a functional-programming language with a derivative- taking operator implemented with forward-mode automatic differentiation (AD). The primary technical difficulty in doing so lies in ensuring correctness in the face of nested invocation of that operator, due to the need to distinguish perturbations introduced by distinct invocations. We exhibit a series of implementations of a referentially- transparent forward-mode-AD derivative-taking operator, each of which uses a different non-referentially-transparent mechanism to distinguish perturbations. Even though the forward-mode-AD derivative-taking operator is itself referentially transparent, we hypothesize that one cannot correctly formulate this operator as a function definition in current pure …

An Efficient Network Model For Determining The Effective Thermal Conductivity Of Particulate Thermal Interface Materials, S Kanuparthi, G Subbarayan, Thomas Siegmund, B Sammakia

School of Mechanical Engineering Faculty Publications

Particulate composites are commonly used in Microelectronics applications. One example of such materials is Thermal Interface Materials (TIMs) that are used to reduce the contact resistance between the chip and the heat sink. The existing analytical descriptions of thermal transport in particulate systems do not accurately account for the effect of inter-particle interactions, especially in the intermediate volume fractions of 30-80%. Another crucial drawback in the existing analytical as well as the network models is the inability to model size distributions (typically bimodal) of the filler material particles that are obtained as a result of the material manufacturing process. While …

"... A Good Imagination And A Pile Of Junk.", Shawn Jordan, Robin S. Adams

School of Engineering Education Graduate Student Series

The engineering workplace is placing more emphasis on teamwork in interdisciplinary environments, out-of-the-box thinking, creative engineering, and brainstorming. These skills are taught to varying degrees in standard engineering curriculums, and often the most fruitful opportunities exist for students to learn in venues outside of the classroom.

This paper will show how building Rube Goldberg machines is a fantastic way for learners from various disciplines to get hands-on project experience in a team environment. Intense brainstorming and work sessions result in inventive and unique machines that are fascinating for both participants and spectators to watch. In addition, students have opportunities to …

Quantum Dots: Bringing Nanoscience And Engineering Into The High School Classroom, Shanna R Daly, Lynn Bryan, Emily D Wischow

School of Engineering Education Graduate Student Series

No abstract provided.

Artificial Intelligence Methods To Forecast Engineering Students' Retention Based On Cognitive And Non Cognitive Factors, Jien-Jou Lin, Alexander Malyscheff, P.K. Imbrie

School of Engineering Education Graduate Student Series

No abstract provided.

Application Of The Dsmc Method For Design Of A Coaxial Microthruster Nozzle, William B. Stein, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

The Direct Simulation Monte Carlo (DSMC) method is used to numerically simulate and design a micronozzle with improved performance. Thrust calculations using the DSMC method demonstrate that the coaxial micronozzles can achieve milli-Newton thrust levels with specific impulses on the order of 45 s using argon in a cold gas expansion. Improved micronozzle designs of coaxial microthrusters are also proposed. Coaxial micronozzles utilizing center-body geometries to exploit pressure thrust show about 140% increase in specific impulse at low Reynolds numbers compared to a traditional converging nozzle.

Hollo-Bolt®: Blind Connector For Structural Steelwork, Purdue Ect Team

ECT Fact Sheets Archive

Structural steel connections for connecting to square, rectangular or circular structural tube or to conventional steel where access is available from one side only poses problems. A technology was needed which could provide a quicker and tidier installation than traditional methods such as welding, unsightly strapping or drilling and tapping holes. The invention of the Hollo-Bolt® provided such a solution.

Smartball™: Free Swimming Leak Detection System, Purdue Ect Team

ECT Fact Sheets Archive

Leak detection systems measure ultrasonic noise, infrared temperature variances or electrical flux to detect leakage in structures like, pipes, tanks, geo-membrane retaining structures etc. SmartBall® is a free flowing leak detection system developed by Pure Technologies. It consists of a foam ball that has a smaller aluminum ball at its core. This aluminum core houses an ultrasonic device that sends ultrasonic signals and also collects the reflected sound waves.

Gas-Phonon Interaction Model For Subcontinuum Thermal Transport Simulations, Xiaohui Guo, Dhruv Singh, Jayathi Murthy, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

Subcontinuum thermal transport problems such as the contact thermal resistance of semiconductor-gas interactions may play an important role in micro/nano-scale devices. In present work, a gas-phonon interaction modeling approach is suggested based on Boltzmann transport equations. Verification has been conducted by comparisons with asymptotic analytical solutions as well as previously reported numerical results and experimental data. Thermal transpiration in nano-sized channels and thermal resistance of nano-sized constrictions has been studied using the current model Thermal transpiration is the main mechanism for temperature driven pumps in nano/micro-devices. In order to maintain higher temperature ratio between the two ends of the gas …

Determination Of Superior Surface Strains And Stresses, And Vocal Fold Contact Pressure In A Synthetic Larynx Model Using Digital Image Correlation, Mychal Spencer, Thomas Siegmund, Luc Mongeau

School of Mechanical Engineering Faculty Publications

No abstract provided.

Modeling Of Spin Metal-Oxide-Semiconductor Field-Effect Transistor: A Nonequilibrium Green’S Function Approach With Spin Relaxation, Tony Low, Mark S. Lundstrom, Dmitri E. Nikonov

Department of Electrical and Computer Engineering Faculty Publications

A spin metal-oxide-semiconductor field-effect transistor spin MOFSET, which combines a Schottky-barrier MOFSET with ferromagnetic source and drain contacts, is a promising device for spintronic logic. Previous simulation studies predict that this device should display a very high magnetoresistance MR ratio between the cases of parallel and anitparallel magnetizations for the case of half-metal ferromagnets HMF. We use the nonequilibrium Green’s function formalism to describe tunneling and carrier transport in this device and to incorporate spin relaxation at the HMF-semiconductor interfaces. Spin relaxation at interfaces results in nonideal spin injection. Minority spin currents arise and dominate the leakage current for antparallel …

Influence Of Phonon Scattering On The Performance Of P-I-Np-I-N Band-To-Band Tunneling Transistors, Siyuranga O. Koswatta, Mark S. Lundstrom, Dmitri E. Nikonov

Department of Electrical and Computer Engineering Faculty Publications

Power dissipation has become a major obstacle in performance scaling of modern integrated circuits and has spurred the search for devices operating at lower voltage swing. In this letter, we study p-i-n band-to-band tunneling field effect transistors taking semiconducting carbon nanotubes as the channel material. The on current of these devices is mainly limited by the tunneling barrier properties, and phonon-scattering has only a moderate effect.We show, however, that the off current is limited by phonon absorption assisted tunneling, and thus is strongly temperature dependent. Subthreshold swings below the 60 mV/decade conventional limit can be readily achieved even at room …

Inversion Capacitance-Voltage Studies On Gaas Metal-Oxide-Semiconductor Structure Using Transparent Conducting Oxide As Metal Gate, T. Yang, Y. Liu, P. D. Ye, Y. Xuan, H. Pal, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

A systematic capacitance-voltage C-V study has been performed on GaAs metaloxide- semiconductor MOS structures with atomic-layer-deposited Al2O3 as gate dielectrics and indium tin oxide ITO as the metal gate. The transparent conducting ITO gate allows homogeneous photoillumination on the whole MOS capacitance area, such that one can easily observe the low-frequency LF C-V and quasistatic C-V of GaAs at room temperature. The semiconductor capacitance effect on GaAs MOS devices has also been identified and insightfully discussed based on the obtained LF C-V curves. The semiconductor capacitance effect becomes more important for devices with high-mobility channel materials and aggressively scaled high-k …

A New Paradigm For Human Resuscitation Research Using Intelligent Devices, Charles F. Babbs, Andre E. Kemeny, Weilun Quan, Gary Freeman

Weldon School of Biomedical Engineering Faculty Publications

Objectives: To develop new methods for studying correlations between the performance and outcome of resuscitation efforts in real-world clinical settings using data recorded by automatic devices such as automatic external defibrillators (AEDs), and to explore effects of shock timing and chest compression depth in the field. Methods: In 695 records of AED use in the pre-hospital setting, continuous compression data were recorded using AEDs capable of measuring sternal motion during compressions, together with timing of delivered shocks and the electrocardiogram. In patients who received at least one shock, putative return of spontaneous circulation (P-ROSC) was defined as a regular, narrow …

Inferring Undesirable Behavior From P2p Traffic Analysis, Ruben Torres, Mohammad Hajjat, Sanjay G. Rao, Marco Mellia, Maurizio Munafo

Department of Electrical and Computer Engineering Technical Reports

ABSTRACT While peer-to-peer (P2P) systems have emerged in popularity in recent years, their large-scale and complexity make them difficult to reason about. In this paper, we argue that systematic analysis of traffic characteristics of P2P systems can reveal a wealth of information about their behavior, and highlight potential undesirable activities that such systems may exhibit. As a first step to this end, we present an offline and semi-automated approach to detecting undesirable behavior. Our analysis is applied on real traffic traces collected from a Point-of-Presence (PoP) of a national-wide ISP in which over 70% of the total traffic is due …

Experimental And Computational Investigation Of A Rf Plasma Micro-Thruster, J D. Olliges, A D. Ketsdever, W B. Stein, Alina A. Alexeenko, I Hrbud

School of Aeronautics and Astronautics Faculty Publications

A prototype RF plasma micro-thruster has been investigated numerically and experimentally. The experimental results were obtained on a thrust stand capable of micro-Newton resolution. Thrust and mass flow (hence specific impulse) were measured for an argon propellant at mass flows ranging from 0.4 to 5.5 mg/s. An increase over the cold gas thrust of up to 20% was observed for a discharge frequency of 100 MHz and an input power of 77 W. Propulsive efficiency was seen to increase both experimentally and numerically for increasing mass flow and decreasing discharge frequency.

Plasma-Neutral Heat Transfer In Coaxial Rf Argon Discharges, William B. Stein, Alina A. Alexeenko, Ivana Hrbud

School of Aeronautics and Astronautics Faculty Publications

Particle-in-cell/Monte Carlo Collision (PIC/MCC) algorithms comprise a numerical model to assess the discharge characteristics of an RF plasma microthruster concept that exploits an RF capacitively coupled discharge (RFCCD) to heat a propellant. The effects of heat transfer between the discharge and the neutral species on microthruster performance are discussed. Heat transfer within the plasma discharge has been shown to greatly affect the discharge characteristics and thruster performance. Increasing the neutral temperature reduces the amount of power transmitted into the fluid through a reduction of the neutral density, and thus reduces effectiveness of the discharge. The PIC/MCC modeling showed that the …

Experimental And Computational Study Of Area And Perimeter Contributions To Radiometer Forces, N P. Selden, S F. Gimelshein, E P. Muntz, Alina A. Alexeenko, A D. Ketsdever

School of Aeronautics and Astronautics Faculty Publications

The relative contribution to the radiometric force of the area and perimeter of the vane is studied experimentally and numerically. Experimentally, a circular vane, a low-aspect rectangular vane, and a high-aspect rectangular vane were all tested on a force balance, with nano-Newton resolution, placed in a stagnant gas. The computational results were obtained through 2-D simulations using the direct simulation Monte Carlo method, as well as a discrete ordinate solution of the ES model kinetic equation. Gas pressure was varied from 0.006 to 6 Pa, which was a broad enough range to observe the characteristic peak force production of a …

Non-Equilibrium Flow Modeling Using High-Order Schemes For The Boltzmann Model Equations, S Chigullapalli, A Venkattraman, Alina A. Alexeenko, M S. Ivanov

School of Aeronautics and Astronautics Faculty Publications

We consider application of higher-order schemes to the Boltzmann model equations with a goal to develop a deterministic computational approach that is accurate and efficient for simulating flows involving a wide range of Knudsen numbers. The kinetic equations are solved for two non-equilibrium flow problems, namely, the structure of a normal shock wave and an unsteady two-dimensional shock tube. The numerical method comprises the discrete velocity method in the velocity space and the finite volume discretization in physical space with different numerical flux schemes: the first-order, the second-order minmod flux limiter as well as a third-order WENO scheme. The normal …

Comparison Of Two Peer Evaluation Instruments For Project Teams, Kerry Meyers, Stephen Silliman, Matthew Ohland, Leo Mcwilliams, Tracy Kijewski-Correa

School of Engineering Education Faculty Publications

The College of Engineering at the University of Notre Dame has utilized a paper-pencil instrument for peer evaluations since 2005 as a portion of the assessment of project team efforts (typically 4-5 students per team) in its First Year Engineering Course. The College was considering moving from paper-pencil peer evaluations to an on-line, behaviorally based evaluation instrument, CATME1. The instructors at Notre Dame conducted a comparative study of student feedback on these two instruments during the fall 2007. During the fall semester, the students (~380) within the first year course were divided into two groups, one group using the paper-pencil …

Impact Of Feedback And Revision On Student Team Solutions To Model Eliciting Activities, Matthew Verleger, Heidi Diefes-Dux

School of Engineering Education Graduate Student Series

Helping first-year engineering students to embrace the iterative and open-ended nature of engineering problem solving is a challenge when their prior learning experiences have focused heavily on achieving a correct answer in a single attempt. In this paper, the authors will present a case study of student work from the Fall 2007 implementation of Model-Eliciting Activities (MEAs) to demonstrate the impact of the iterative process of feedback and revision on the quality of student products. They will also discuss some of the future research questions resulting from the iterative process used with MEAs.

Professors’ Instructional Approaches And Students’ Perceptions Of Nanohub Simulations As Learning Tools, Alejandra De Jesus Magana De Leon, George Bodner, Sean B. Brophy

School of Engineering Education Graduate Student Series

No abstract provided.

Implementation Of Station Health Monitoring Procedures For Its Sensors, Volume 2: Implementation Report, Joseph M. Ernst, Darcy M. Bullock

JTRP Technical Reports

No abstract provided.

Durability And Retro-Reflectivity Of Pavement Markings (Synthesis Study), Yi Jiang

JTRP Technical Reports

Waterborne paints are used to paint pavement markings (edgelines and centerlines) to provide guidance for motorists. The painted markings need to be repainted periodically as their retro-reflectivity deteriorates. The Indiana Department of Transportation (INDOT) repaints pavement markings at least annually. INDOT engineers would like to determine the feasibility of extending the time intervals of repainting pavement markings on at least some types of roadways. The purpose of this synthesis study is to accomplish the following: (1) to locate and assemble documented information on pavement marking durability; (2) to learn what criteria have been used in other states in measuring retro-reflectivity …

Deck Replacement - Use Of Extra Coating Thickness Epoxy-Coated Bars, J. A. Ramirez, Rachel Elizabeth Henkhaus

JTRP Technical Reports

The results of this study were implemented in the form of design recommendations for bond of epoxy-coated bars with thicker coatings up to 18 mils. The scope of the work included evaluation of AASHTO LRFD (2004) and ACI 318 design recommendedations for the development and splice length of extra epoxy-coating thinkness reinforcing bars in normal-weight concrete bridge decks and a proposed monitoring plan for a generic concrete bridge deck in Indiana where epoxy-coated bars with thicker coatings might be emeployed. The use of the current provisions for development and splice length of epoxy-coated bars in tension in both the AASHTO …

Acquisition And Analysis Of Earthwork Pay Quantity Verification Data, Sharvil Saurabh Shah, Makarand Hastak

JTRP Technical Reports

This research identifies technologies and methods that can be used by INDOT in earthwork data collection and earthwork quantity calculation process on large construction projects that could result in timely completion of the projects with less labor and resultant cost. In order to achieve the above stated objective, several tasks were performed, i.e., literature review, data collection, data analysis, and recommendations. INDOT engineers were interviewed to determine their current state of practice. Also, all the state DOTs, professional companies in Indiana and vendors of earthwork data collection equipment and software products were contacted through questionnaire surveys and personal interviews. Two …

2006 Summary Of Highway Revenues, Distributions, & Expenses For Indiana Counties, Cities, & Towns, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This report provides information on revenues, distributions, and expenses of state and local governments for highway, road, and street work. Since the Motor Vehicle Highway (MVH) and Local Road and Street (LRS) Accounts are the principal source of funds for local road or street construction and maintenance operations, this summary may be used to see the trends in income sources and in the expenses charged to the funds prior to their being distributed to the highway, road, and street agencies.

Simulation Of Phonon Transport Across A Non-Polar Nanowire Junction Using An Atomistic Green's Function Method, W Zhang, N Mingo, Timothy Fisher

Birck and NCN Publications

Phonon transport across a non-polar nanowire situated between two semi-infinite contacts is simulated in this paper using the atomistic Green's function method. Abrupt geometric changes between the nanowire and bulk contacts are handled by self-energy matrices obtained from bare surface Green's functions. Transport properties such as phonon transmission functions and thermal conductances are calculated, and their dependencies on the interatomic potential, length, diameter, shape, and lattice orientation are investigated. The results reveal that the overall thermal conductance of the nanowire-bulk-contact structure increases with nanowire diameter while the normalized thermal conductance approaches an asymptotic value. Thermal conductance decreases significantly with increasing …

Gold Nanorods Mediate Tumor Cell Death By Compromising Membrane Integrity, Ling Tong, Yan Zhao, Terry B. Huff, Matthew N. Hansen, Alexander Wei, Ji-Xin Cheng

Other Nanotechnology Publications

Folate-conjugated gold nanorods targeted to tumor cell surfaces produced severe membrane damage upon near-infrared irradiation. Photoinduced injury to the plasma membrane resulted in a rapid increase in intracellular calcium (shown in green) with subsequent disruption of the actin network, featured prominently by the formation of membrane blebs.

2007 Summary Of Major Moves Money Distribution, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This report contains a summary of local units' use of the Major Moves funding to enhance their transportation systems provided for by the Indiana Legislature passing of House Bill 1008 on March 14, 2006.

The information contained herein is from either written or verbal responses to a survey that was sent to all Indiana counties and to the Indiana cities and towns over 20,000 in population. A copy of this survey can be found in the Appendix. In Appendix I, you will find a copy of the survey that was sent. Appendix II contains a table containing a breakdown of …