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2011

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Full-Text Articles in Engineering

A Benchmark Study On The Thermal Conductivity Of Nanofluids, Jacopo Buongiorno, David Venerus, Naveen Prabhat, Thomas Mckrell, Jessica Townsend, Rebecca Christianson, Yuriv Tolmachev, Pawel Keblinski, Lin-Wen Hu, Jorge Alvarado, In Cheol Bang, Sandra Bishnoi, Marco Bonetti, Frank Botz, Anselmo Cecere, Yun Chang, Gang Chen, Haisheng Chen, Sung Jae Chung, Minking Chyu, Sarit Das, Roberto Di Paola, Yulong Ding, Frank Dubois, Grzegorz Dzido, Jacob Eapen, Werner Escher, Denis Funfschilling, Quentin Galand, Jinwei Gao, Patricia Gharagozloo, Kenneth Goodson, Jorge Gutierrez, Haiping Hong, Mark Horton, Kyo Sik Hwang, Carlo Iorio, Seok Pil Jang, Andrzej Jarzebski, Yiran Jiang, Stephan Kabelac, Liwen Jin, Aravind Kamath, Mark Kedzierski, Lim Geok Kieng, Chongyoup Kim, Ji-Hyun Kim, Seokwon Kim, Seung Hyun Lee, Kai Choong Leong, Indranil Manna, Bruno Michel, Rui Ni, Hrishikesh Patel, John Philip, Dimos Poulikakos, Cecil Reynaud, Raffaele Savino, Pawan Singh, Pengxiang Song, Thirumalachari Sundararajan, Elena Timofeeva, Todd Tritcak, Aleksandr Turanov, Stefan Van Vaerenbergh, Dongsheng Wen, Sanjeeva Witharana, Chun Yang, Wei-Hsun Yeh, Xiao-Zheng Zhao, Sheng-Qi Zhou Dec 2011

A Benchmark Study On The Thermal Conductivity Of Nanofluids, Jacopo Buongiorno, David Venerus, Naveen Prabhat, Thomas Mckrell, Jessica Townsend, Rebecca Christianson, Yuriv Tolmachev, Pawel Keblinski, Lin-Wen Hu, Jorge Alvarado, In Cheol Bang, Sandra Bishnoi, Marco Bonetti, Frank Botz, Anselmo Cecere, Yun Chang, Gang Chen, Haisheng Chen, Sung Jae Chung, Minking Chyu, Sarit Das, Roberto Di Paola, Yulong Ding, Frank Dubois, Grzegorz Dzido, Jacob Eapen, Werner Escher, Denis Funfschilling, Quentin Galand, Jinwei Gao, Patricia Gharagozloo, Kenneth Goodson, Jorge Gutierrez, Haiping Hong, Mark Horton, Kyo Sik Hwang, Carlo Iorio, Seok Pil Jang, Andrzej Jarzebski, Yiran Jiang, Stephan Kabelac, Liwen Jin, Aravind Kamath, Mark Kedzierski, Lim Geok Kieng, Chongyoup Kim, Ji-Hyun Kim, Seokwon Kim, Seung Hyun Lee, Kai Choong Leong, Indranil Manna, Bruno Michel, Rui Ni, Hrishikesh Patel, John Philip, Dimos Poulikakos, Cecil Reynaud, Raffaele Savino, Pawan Singh, Pengxiang Song, Thirumalachari Sundararajan, Elena Timofeeva, Todd Tritcak, Aleksandr Turanov, Stefan Van Vaerenbergh, Dongsheng Wen, Sanjeeva Witharana, Chun Yang, Wei-Hsun Yeh, Xiao-Zheng Zhao, Sheng-Qi Zhou

Rebecca J. Christianson

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about …


Modeling All Spin Logic: Multi-Magnet Networks Interacting Via Spin Currents, Srikant Srinivasan Dec 2011

Modeling All Spin Logic: Multi-Magnet Networks Interacting Via Spin Currents, Srikant Srinivasan

Srikant Srinivasan

All-spin logic (ASL) represents a new approach to information processing where the roles of charges and capacitors in CMOS are played by spins and magnets. This paper (1) summarizes our earlier work on the input-output isolation and intrinsic directivity of ASL devices, (2) uses an experimentally benchmarked simulator for multimagnet networks coupled by spin transport channels to demonstrate a combinational NAND gate, and (3) describes the natural mapping of such ASL networks into neuromorphic circuits suitable for hybrid analog/digital information processing.


From Pollen To Polyester, Debbie Chachra Nov 2011

From Pollen To Polyester, Debbie Chachra

Debbie Chachra

Polyester bees are all over the Northeast. The interesting thing about them is that they dig underground tunnels, about the width of your pinky finger, where they lay their eggs. To protect their larvae from heat, cold, fungus, bacteria and other dangers, the bees line these chambers with a clear, cellophanelike substance. The larvae then live underground for most of their lives in these reinforced cells.


Directed Cellular Self-Assembly To Fabricate Cell-Derived Tissue Rings For Biomechanical Analysis And Tissue Engineering, Kristen Billiar, Tracy Gwyther, Jason Hu, Marsha Rolle Nov 2011

Directed Cellular Self-Assembly To Fabricate Cell-Derived Tissue Rings For Biomechanical Analysis And Tissue Engineering, Kristen Billiar, Tracy Gwyther, Jason Hu, Marsha Rolle

Kristen L. Billiar

Each year, hundreds of thousands of patients undergo coronary artery bypass surgery in the United States.1 Approximately one third of these patients do not have suitable autologous donor vessels due to disease progression or previous harvest. The aim of vascular tissue engineering is to develop a suitable alternative source for these bypass grafts. In addition, engineered vascular tissue may prove valuable as living vascular models to study cardiovascular diseases. Several promising approaches to engineering blood vessels have been explored, with many recent studies focusing on development and analysis of cell-based methods.2-5 Herein, we present a method to rapidly self-assemble cells …


Efficient Database Generation For Decision Tree Based Power System Security Assessment, Venkat Krishnan Nov 2011

Efficient Database Generation For Decision Tree Based Power System Security Assessment, Venkat Krishnan

Venkat Kumar Krishnan

No abstract provided.


Adding Value To Physics Laboratories For Pre-Service Teachers, Lorna Jarrett, George Takacs, Brian Ferry Nov 2011

Adding Value To Physics Laboratories For Pre-Service Teachers, Lorna Jarrett, George Takacs, Brian Ferry

George Takacs

This project focussed on first-year physics laboratories for pre-service teachers. It aimed to make laboratories more aligned to future teachers’ needs; contributing to their confidence with apparatus, conceptual understanding and effectiveness as communicators. However, our approach is also relevant to mainstream science laboratories. First, we flagged links with practical investigations in the NSW High School year 11 / 12 physics syllabus in the lab manual. Second, we incorporated qualitative multiple-choice questions at strategic points based on the Peer Instruction work of Mazur (1996), Crouch and Mazur (2001) and Cox and Junkin III (2002). Finally we employed principles of Cognitive Load …


Adding Value To Physics Labs To Help Build Confident, Knowledgeable Teachers, Lorna Jarrett, Brian Ferry, George Takacs Nov 2011

Adding Value To Physics Labs To Help Build Confident, Knowledgeable Teachers, Lorna Jarrett, Brian Ferry, George Takacs

George Takacs

Abstract: This pilot study is being conducted by an interdisciplinary team and is funded through the University of Wollongong Education Strategies Development Fund. The project focuses on the first-year physics laboratories of pre- service teachers enrolled in Bachelor of Science Education degrees. It aims to make the laboratory experience more aligned to the needs of future science and physics teachers, contributing to their confidence in using apparatus in the classroom and their effectiveness as communicators who can explain concepts fluently from a background of deep understanding. According to Mulhall (2006) and Johnston and Millar (2000), misconceptions are common even among …


Microbeam Radiation Therapy: A Monte Carlo Study Of The Influence Of The Source, Multislit Collimator, And Beam Divergence On Microbeams, Heidi Nettelbeck, George Takacs, Michael Lerch, Anatoly Rosenfeld Nov 2011

Microbeam Radiation Therapy: A Monte Carlo Study Of The Influence Of The Source, Multislit Collimator, And Beam Divergence On Microbeams, Heidi Nettelbeck, George Takacs, Michael Lerch, Anatoly Rosenfeld

George Takacs

Microbeam radiation therapy (MRT) is a new oncology method currently under development for the treatment of inoperable pediatric brain tumors. Monte Carlo simulation, or the computational study of radiation transport in matter, is often used in radiotherapy to theoretically estimate the dose required for treatment. However, its potential use in MRT dose planning systems is currently hindered by the significant discrepancies that have been observed between measured and theoretical dose and the PVDR (peak to valley dose ratio). The need to resolve these discrepancies is driven by the desirability of making MRT available to humans in the next few years. …


Miniature Semiconductor Detectors For In Vivo Dosimetry, Anatoly Rosenfeld, Dean Cutajar, Michael Lerch, George Takacs, Iwan Cornelius, M Yudelev, M Zaider Nov 2011

Miniature Semiconductor Detectors For In Vivo Dosimetry, Anatoly Rosenfeld, Dean Cutajar, Michael Lerch, George Takacs, Iwan Cornelius, M Yudelev, M Zaider

George Takacs

Silicon mini-semiconductor detectors are found in wide applications for in vivo personal dosimetry and dosimetry and microdosimetry of different radiation oncology modalities. These applications are based on integral and spectroscopy modes of metal oxide semiconductor field effect transistor and silicon p–n junction detectors. The advantages and limitations of each are discussed.


Effect Of Transverse Magnetic Fields On Dose Distribution And Rbe Of Photon Beams: Comparing Penelope And Egs4 Monte Carlo Codes, Heidi Nettelbeck, George Takacs, Anatoly Rosenfeld Nov 2011

Effect Of Transverse Magnetic Fields On Dose Distribution And Rbe Of Photon Beams: Comparing Penelope And Egs4 Monte Carlo Codes, Heidi Nettelbeck, George Takacs, Anatoly Rosenfeld

George Takacs

The application of a strong transverse magnetic field to a volume undergoing irradiation by a photon beam can produce localized regions of dose enhancement and dose reduction. This study uses the PENELOPE Monte Carlo code to investigate the effect of a slice of uniform transverse magnetic field on a photon beam using different magnetic field strengths and photon beam energies. The maximum and minimum dose yields obtained in the regions of dose enhancement and dose reduction are compared to those obtained with the EGS4 Monte Carlo code in a study by Li et al (2001), who investigated the effect of …


Influence Of Glycosaminoglycan Identity On Vocal Fold Fibroblast Behavior, Andrea Jimenez-Vergara, Dany Munoz Pinto, Silvia Becerra-Bayona, Bo Wang, Alexandra Iacob, Mariah Hahn Oct 2011

Influence Of Glycosaminoglycan Identity On Vocal Fold Fibroblast Behavior, Andrea Jimenez-Vergara, Dany Munoz Pinto, Silvia Becerra-Bayona, Bo Wang, Alexandra Iacob, Mariah Hahn

Dany J. Munoz Pinto

Poly(ethylene glycol) (PEG) hydrogels have recently begun to be studied for the treatment of scarred vocal fold lamina propria due, in part, to their tunable mechanical properties, resistance to fibroblast-mediated contraction, and ability to be polymerized in situ. However, pure PEG gels lack intrinsic biochemical signals to guide cell behavior and generally fail to mimic the frequency-dependent viscoelastic response critical to normal superficial lamina propria function. Recent results suggest that incorporation of viscoelastic bioactive substances, such as glycosaminoglycans (GAGs), into PEG networks may allow these gels to more closely approach the mechanical responses of normal vocal fold lamina propria while …


Parameter Estimation For Mechanical Systems Via An Explicit Representation Of Uncertainty, Emmanuel Blanchard, Adrian Sandu, Corina Sandu Oct 2011

Parameter Estimation For Mechanical Systems Via An Explicit Representation Of Uncertainty, Emmanuel Blanchard, Adrian Sandu, Corina Sandu

Emmanuel Blanchard

Purpose – The purpose of this paper is to propose a new computational approach for parameter estimation in the Bayesian framework. A posteriori probability density functions are obtained using the polynomial chaos theory for propagating uncertainties through system dynamics. The new method has the advantage of being able to deal with large parametric uncertainties, non-Gaussian probability densities and nonlinear dynamics. Design/methodology/approach – The maximum likelihood estimates are obtained by minimizing a cost function derived from the Bayesian theorem. Direct stochastic collocation is used as a less computationally expensive alternative to the traditional Galerkin approach to propagate the uncertainties through the …


A Polynomial Chaos-Based Kalman Filter Approach For Parameter Estimation Of Mechanical Systems, Emmanuel Blanchard, Corina Sandu, Adrian Sandu Oct 2011

A Polynomial Chaos-Based Kalman Filter Approach For Parameter Estimation Of Mechanical Systems, Emmanuel Blanchard, Corina Sandu, Adrian Sandu

Emmanuel Blanchard

Mechanical systems operate under parametric and external excitation uncertainties. The polynomial chaos approach has been shown to be more efficient than Monte Carlo for quantifying the effects of such uncertainties on the system response. Many uncertain parameters cannot be measured accurately, especially in real time applications. Information about them is obtained via parameter estimation techniques. Parameter estimation for large systems is a difficult problem, and the solution approaches are computationally expensive. This paper proposes a new computational approach for parameter estimation based on the extended Kalman filter (EKF) and the polynomial chaos theory for parameter estimation. The error covariances needed …


Polynomial Chaos-Based Parameter Estimation Methods Applied To A Vehicle System, Emmanuel Blanchard, Adrian Sandu, Corina Sandu Oct 2011

Polynomial Chaos-Based Parameter Estimation Methods Applied To A Vehicle System, Emmanuel Blanchard, Adrian Sandu, Corina Sandu

Emmanuel Blanchard

Parameter estimation for large systems is a difficult problem, and the solution approaches are computationally expensive. The polynomial chaos approach has been shown to be more efficient than Monte Carlo for quantifying the effects of uncertainties on the system response. This article compares two new computational approaches for parameter estimation based on the polynomial chaos theory for parameter estimation: a Bayesian approach, and an approach using an extended Kalman filter (EKF) to obtain the polynomial chaos representation of the uncertain states and the uncertain parameters. The two methods are applied to a non-linear four-degree-of-freedom roll plane model of a vehicle, …


Fuzzy Controller For Seismically Excited Nonlinear Buildings, M. Al-Dawod, B. Samali, K. Kwok, Fazel Naghdy Oct 2011

Fuzzy Controller For Seismically Excited Nonlinear Buildings, M. Al-Dawod, B. Samali, K. Kwok, Fazel Naghdy

Professor Fazel Naghdy

This paper focuses on the benchmark control problems for seismically excited nonlinear buildings. The benchmark study focuses on three typical steel structures, 3-, 9-, and 20-story buildings designed for the SAC project for the Los Angeles region. This paper reports the application of the active control scheme on the 3- and 20-story benchmark buildings, where the control action is achieved by a fuzzy logic controller. The main advantage of the fuzzy controller is its inherent robustness and ability to handle any nonlinear behavior of the structure. The performance of the controller is validated through the computer simulation on MATLAB. The …


Factorial Design Analysis For Dye-Sensitized Hydrogen Generation From Water, Pankaj Chowdhury, Hassan Gomaa, Ajay Ray Sep 2011

Factorial Design Analysis For Dye-Sensitized Hydrogen Generation From Water, Pankaj Chowdhury, Hassan Gomaa, Ajay Ray

PC

A factorial design at two levels and four factors has been carried out in order to investigate the potential for hydrogen generation using Eosin Y-sensitized TiO2/Pt catalyst under visible solar light in presence of triethanolamine (TEOA) as electron donor. The solution pH was found to be a significant parameter, and was maintained at pH 7.0 throughout the investigation. Visible light irradiation time (I-time) showed highest positive effect on hydrogen generation followed by initial Eosin Y concentration (for dye-sensitization) and the TEOA concentration while Pt content (wt %) in TiO2 showed negative effect toward hydrogen generation. Experimental data were analyzed using …


Lung Cancer Brachytherapy: Robotics-Assisted Minimally Invasive Approach, Edward Yu, Craig Lewis, Ana Trejos, Rajni Patel, Richard Malthaner Sep 2011

Lung Cancer Brachytherapy: Robotics-Assisted Minimally Invasive Approach, Edward Yu, Craig Lewis, Ana Trejos, Rajni Patel, Richard Malthaner

Edward Yu

New technological concepts have been evolving to manage the relative poor prognosis of lung cancer. Brachytherapy is becoming an option for both unresectable and early resectable lung cancer. Three-dimensional ultrasound (US) of lung tumours and image-guided minimally invasive robotics-assisted brachytherapy are feasible for dosimetry planning and management of lung tumours. The present article reviews the current knowledge of lung brachytherapy and discusses its potential in future management of lung cancer.


Integrating Thermodynamic And Observed-Frequency Data For Non-Coding Rna Gene Search, Jennifer Smith, Kay Wiese Aug 2011

Integrating Thermodynamic And Observed-Frequency Data For Non-Coding Rna Gene Search, Jennifer Smith, Kay Wiese

Jennifer A. Smith

Among the most powerful and commonly used methods for finding new members of non-coding RNA gene families in genomic data are covariance models. The parameters of these models are estimated from the observed position-specific frequencies of insertions, deletions, and mutations in a multiple alignment of known non-coding RNA family members. Since the vast majority of positions in the multiple alignment have no observed changes, yet there is no reason to rule them out, some form of prior is applied to the estimate. Currently, observed-frequency priors are generated from non-family members based on model node type and child node type allowing …


Efficient Non-Coding Rna Gene Searches Through Classical And Evolutionary Methods, Jennifer Smith Aug 2011

Efficient Non-Coding Rna Gene Searches Through Classical And Evolutionary Methods, Jennifer Smith

Jennifer A. Smith

Successful non-coding RNA gene searching requires examination of long-range intramolecular base pairing possibilities. This results in search algorithms with extremely long run times such that large-scale use of the algorithms often becomes computationally infeasible. Methods for the efficient search of the solution space are examined. A review of the standard dynamic-programming covariance model search algorithm is given. An analysis of the statistically probable regions of the search space is undertaken and a method of limiting the traditional dynamic-programming algorithm to this region is shown. An alternative search method using a Genetic Algorithm (GA) which favours the probable region of the …


Digital Filter Design For Jamming Mitigation In 802.15.4 Communication, Bruce Debruhl, Patrick Tague Jul 2011

Digital Filter Design For Jamming Mitigation In 802.15.4 Communication, Bruce Debruhl, Patrick Tague

Patrick Tague

Jamming attackers can dramatically increase attack efficiency and stealth by randomly or periodically cycling the jamming transmission on and off, attacks respectively known as random and periodic jamming. In this paper, we analyze the impact of such attacks on the IEEE 802.15.4 communication protocol, commonly used in wireless sensor networking applications, and show that the cycling behavior introduces a narrow spectral component into the received signal. We propose the inclusion of a digital filter at the receiver side to effectively eliminate this spectral component, and we discuss the benefits involved in this filter design. We evaluate the impacts of random …


Embedding Lifelong Learning Skills Into A First-Year Engineering Course Through Introduction Of An Independent Research Project And Information Literacy Skills, Chris Plouff, Debbie Morrow Jul 2011

Embedding Lifelong Learning Skills Into A First-Year Engineering Course Through Introduction Of An Independent Research Project And Information Literacy Skills, Chris Plouff, Debbie Morrow

Chris Plouff

This paper reports on a work in progress to address ABET program outcome ‘i’ (“graduates have a recognition of the need for, and an ability to engage in, lifelong learning”) in the Bachelor of Science in Engineering programs (mid-size, undergraduate engineering program) at a large Master’s-granting university in the mid-western United States. One performance criterion used by the programs to assess program outcome ‘i’ is the ability to find, evaluate, and effectively use information independently. This concept is introduced in the first-year of the programs, and is reinforced in an intentional thread throughout the curriculum, culminating with the senior capstone …


Purely Electronic Switching With High Uniformity, Resistance Tunability, And Good Retention In Pt-Dispersed Sio2 Thin Films For Reram, Albert Chen Jun 2011

Purely Electronic Switching With High Uniformity, Resistance Tunability, And Good Retention In Pt-Dispersed Sio2 Thin Films For Reram, Albert Chen

Albert B Chen

Resistance switching memory operating by a purely electronic switching mechanism, which was first realized in Pt-dispersed SiO2 thin films, satisfies criteria including high uniformity, fast switching speed, and long retention for non-volatile memory application. This resistive element obeys Ohm's law for the area dependence, but its resistance exponentially increases with the film thickness, which provides new freedom to tailor the device characteristics.


Metamaterials On Parylene Thin Film Substrates: Design, Fabrication, And Characterization At Terahertz Frequency, Xianliang Liu, Samuel Macnaughton, David Shrekenhamer, Hu Tao, Selvapraba Selvarasah, Atcha Totachawattana, Richard Averitt, Mehmet Dokmeci, Sameer Sonkusale, Willie Padilla Jun 2011

Metamaterials On Parylene Thin Film Substrates: Design, Fabrication, And Characterization At Terahertz Frequency, Xianliang Liu, Samuel Macnaughton, David Shrekenhamer, Hu Tao, Selvapraba Selvarasah, Atcha Totachawattana, Richard Averitt, Mehmet Dokmeci, Sameer Sonkusale, Willie Padilla

Mehmet R. Dokmeci

We design, fabricate, and characterize terahertz (THz) resonant metamaterials on parylene free-standing thin film substrates. Several different metamaterials are investigated and our results show strong electromagnetic responses at THz frequencies ranging from 500 GHz to 2.5 THz. The complex frequency dependent dielectric properties of parylene are determined from inversion of reflection and transmission data, thus indicating that parylene is an ideal low loss substrate or coating material. The biostable and biocompatible properties of parylene coupled with the multifunctional exotic properties of metamaterials indicate great potential for medical purposes such as THz imaging for skin cancer detection.


Direct Measurement Of Graphene Adhesion On Silicon Surface By Intercalation Of Nanoparticles, Zong Zong, Chia-Ling Chen, Mehmet Dokmeci, Kai-Tak Wan Jun 2011

Direct Measurement Of Graphene Adhesion On Silicon Surface By Intercalation Of Nanoparticles, Zong Zong, Chia-Ling Chen, Mehmet Dokmeci, Kai-Tak Wan

Mehmet R. Dokmeci

We report a technique to characterize adhesion of monolayered/multilayered graphene sheets on silicon wafer. Nanoparticles trapped at graphene-silicon interface act as point wedges to support axisymmetric blisters. Local adhesion strength is found by measuring the particle height and blister radius using a scanning electron microscope. Adhesion energy of the typical graphene-silicon interface is measured to be 151±28 mJ/m2. The proposed method and our measurements provide insights in fabrication and reliability of microelectromechanical/nanoelectromechanical systems.


Low-Voltage And Short-Channel Pentacene Field-Effect Transistors With Top-Contact Geometry Using Parylene-C Shadow Masks, Yoonyoung Chung, Boris Murmann, Selvapraba Selvarasah, Mehmet Dokmeci, Zhenan Bao Jun 2011

Low-Voltage And Short-Channel Pentacene Field-Effect Transistors With Top-Contact Geometry Using Parylene-C Shadow Masks, Yoonyoung Chung, Boris Murmann, Selvapraba Selvarasah, Mehmet Dokmeci, Zhenan Bao

Mehmet R. Dokmeci

We have fabricated high-performance top-contact pentacene field-effect transistors using a nanometer-scale gate dielectric and parylene-C shadow masks. The high-capacitance gate dielectric, deposited by atomic layer deposition of aluminum oxide, resulted in a low operating voltage of 2.5 V. The flexible and conformal parylene-C shadow masks allowed fabrication of transistors with channel lengths of L = 5, 10, and 20 μm. The field-effect mobility of the transistors was μ = 1.14 (±0.08) cm²/V s on average, and the IMAX/IMIN ratio was greater than 10⁶.


Persistence, Engagement, And Migration In Engineering Programs, Matthew Ohland, Sheri Sheppard, Gary Lichtenstein, Ozgur Eris, Debbie Chachra, Richard Layton Jun 2011

Persistence, Engagement, And Migration In Engineering Programs, Matthew Ohland, Sheri Sheppard, Gary Lichtenstein, Ozgur Eris, Debbie Chachra, Richard Layton

Debbie Chachra

Records from the Multiple-Institution Database forInvestigating Engineering Longitudinal Development indicatethat engineering students are typical of students in other majorswith respect to: persistence in major; persistence by gender andethnicity; racial/ethnic distribution; and grade distribution. Datafrom the National Survey of Student Engagement show that thissimilarity extends to engagement outcomes including course challenge,faculty interaction, satisfaction with institution, and overallsatisfaction. Engineering differs from other majors most notablyby a dearth of female students and a low rate of migration into themajor. Noting the similarity of students of engineering and othermajors with respect to persistence and engagement, we proposethat engagement is a precursor to persistence. We …


Analysis Of Electroluminescence Spectra Of Silicon And Gallium Arsenide P-N Junctions In Avalanche Breakdown, M Lahbabi, A Ahaitoufa, M. Fliyou, E. Abarkan, J.-P. Charles, A. Bath, A. Hoffmann, Sherra Kerns, David Kerns, Jr. Jun 2011

Analysis Of Electroluminescence Spectra Of Silicon And Gallium Arsenide P-N Junctions In Avalanche Breakdown, M Lahbabi, A Ahaitoufa, M. Fliyou, E. Abarkan, J.-P. Charles, A. Bath, A. Hoffmann, Sherra Kerns, David Kerns, Jr.

David V. Kerns

We present a generalized study of light emission from reverse biased p–n junctions under avalanche breakdown conditions. A model is developed based on direct and indirect interband processes including self-absorption to describe measured electroluminescence spectra. This model was used to analyze experimental data for silicon (Si) and gallium arsenide p–n junctions and can be extended to several types of semiconductors regardless of their band gaps. This model can be used as a noninvasive technique for the determination of the junction depth. It has also been used to explain the observed changes of the Si p–n junction electroluminescence spectra after fast …


Unidirectional Information Transfer With Cascaded All Spin Logic Devices: A Ring Oscillator, Srikant Srinivasan Jun 2011

Unidirectional Information Transfer With Cascaded All Spin Logic Devices: A Ring Oscillator, Srikant Srinivasan

Srikant Srinivasan

The authors have presented the first simulator that simultaneously describes magnetization dynamics as well as spin transport in multi-magnet ASL networks and used it to demonstrate the possibility of large scale functional spin logic blocks through the example of an All Spin ring oscillator.


Mechanical And Electrical Evaluation Of Parylene-C Encapsulated Carbon Nanotube Networks On A Flexible Substrate, Chia-Ling Chen, Ernesto Lopez, Yung-Joon Jung, Sinan Müftü, Selvapraba Selvarasah, Mehmet Dokmeci Jun 2011

Mechanical And Electrical Evaluation Of Parylene-C Encapsulated Carbon Nanotube Networks On A Flexible Substrate, Chia-Ling Chen, Ernesto Lopez, Yung-Joon Jung, Sinan Müftü, Selvapraba Selvarasah, Mehmet Dokmeci

Sinan Müftü

Carbon nanotube networks are an emerging conductive nanomaterial with applications including thin film transistors, interconnects, and sensors. In this letter, we demonstrate the fabrication of single-walled carbon nanotube (SWNT) networks on a flexible polymer substrate and then provide encapsulation utilizing a thin parylene-C layer. The encapsulated SWNT network was subjected to tensile tests while its electrical resistance was monitored. Tests showed a linear-elastic response up to a strain value of 2.8% and nearly linear change in electrical resistance in the 0%–2% strain range. The networks’ electrical resistance was monitored during load-unload tests of up to 100 cycles and was hysteresis-free.


Investigation Of Electrical Transport In Hydrogenated Multiwalled Carbon Nanotubes, Adam Friedman, Hyunkyung Chun, Don Heiman, Yung Jung, Latika Menon Jun 2011

Investigation Of Electrical Transport In Hydrogenated Multiwalled Carbon Nanotubes, Adam Friedman, Hyunkyung Chun, Don Heiman, Yung Jung, Latika Menon

Latika Menon

Highly disordered multiwalled carbon nanotubes of large outer diameter (~60 nm) fabricated by means of chemical vapor deposition process inside porous alumina templates exhibit ferromagnetism when annealed in a H2/Ar atmosphere. In the presence of an applied magnetic field, there is a transition from positive to negative magnetoresistance. The transition may be explained in terms of the Bright model for ordered and disordered carbon structures. Additionally, temperature dependent electrical transport experiments exhibit a zero-bias anomaly at low temperature.