Engineering Commons^™

Interactional Analysis Of Emergent Risks In Institutionally Diverse Construction Projects, Nader Naderpajouh

Open Access Dissertations

Naderpajouh, Nader Ph.D., Purdue University, December 2013. Interactional Analysis of Emergent Risks in Institutionally Diverse Construction Projects. Major Professor: Makarand Hastak.

Construction projects, as complex systems of systems (SOS), increasingly involve institutionally diverse actors that escalate complexity of the projects. Examples of these actors include the export credit agencies, international organizations such as the World Bank, non-governmental organizations (NGO), regulatory actors, transnational organizations, as well as public and community groups. The observed surge in complexity of the projects aim to enhance their robustness in: i) sustaining the increasing demand for service of these projects, and ii) sustaining the contextual fluctuation …

Information Measures For Statistical Orbit Determination, Alinda Kenyana Mashiku

Open Access Dissertations

The current Situational Space Awareness (SSA) is faced with a huge task of tracking the increasing number of space objects. The tracking of space objects requires frequent and accurate monitoring for orbit maintenance and collision avoidance using methods for statistical orbit determination. Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty given by the probability density function (PDF). As even collision events with very low probability are important, accurate prediction of collisions require the representation of the full PDF of the random orbit state. Through representing the full PDF …

Accurate Prediction Of Spectral Phonon Relaxation Time And Thermal Conductivity Of Intrinsic And Perturbed Materials, Tianli Feng

Open Access Theses

The prediction of spectral phonon relaxation time, mean-free-path, and thermal conductivity can provide significant insights into the thermal conductivity of bulk and nanomaterials, which are important for thermal management and thermoelectric applications. We perform frequency-domain normal mode analysis (NMA) on pure bulk argon and pure bulk germanium. Spectral phonon properties, including the phonon dispersion, relaxation time, mean free path, and thermal conductivity of argon and germanium at different temperatures have been calculated. We find the dependence of phonon relaxation time τ on frequency ω and temperature T vary from ~ω^-1.3 to ~ω^-1.8 and ~T^-0.8 to ~T^{-1.8 …}

Design Of A Running Robot And The Effects Of Foot Placement In The Transverse Plane, Timothy James Sullivan

Open Access Theses

The purpose of this thesis is to make advances in the design of humanoid bipedal running robots. We focus on achieving dynamic running locomotion because it is one metric by which we can measure how far robotic technologies have advanced, in relation to existing benchmarks set by humans and other animals. Designing a running human-inspired robot is challenging because human bodies are exceptionally complex mechanisms to mimic. There are only a few humanoid robots designed specifically for running and the existing robots are either constrained to a plane, do not yet exhibit human-like motion, or are unstable.

One aspect of …

Solution Combustion Synthesis Of Cobalt Oxide For Use As A Catalyst Precursor In The Hydrolysis Of Sodium Borohydride, Teandra Leigh Pfeil

Open Access Theses

Solution combustion synthesized (SCS) cobalt oxide (Co₃O₄) powder has been studied as a catalyst precursor for the hydrolysis of sodium borohydride (NaBH₄). Synthesis is completed in less than two minutes and results indicate SCS is capable of reproducibly synthesizing 98.5-99.5% pure Co₃O₄ nano-foam materials. SCS materials demonstrate an as-synthesized specific surface area of 24 m²/g, a crystallite size of 15.5 nm, and fine surface structures on the order of 4 nm. Despite having similar initial surface areas and sample purities, SCS-Co₃O₄ outperforms commercially available Co_{3 …}

Effect Of Exhaust Gas Recirculation And Combustible Oxygen Mass Fraction On Emission Index Of Nox For Counterflow Methane/Air Diffusion Flames, Mugdha S. Sane

Open Access Theses

Exhaust gas recirculation has been proven to be an effective method of reducing emissions of oxides of nitrogen (NOx) from internal combustion engines. The present study validates this effect through flame simulations using detailed chemistry. Counterflow methane/air diffusion flames were simulated in one dimension in physical space using GRI-Mech 3.0 detailed chemistry mechanism, thermal, and transport data. The influence of Exhaust Gas Recirculation (EGR) on the flame structure and NOx emissions was studied by selecting higher than ambient inlet temperature and by varying the composition of the oxidizer stream. The Combustible Oxygen Mass Fraction (COMF), which represents the fraction of …

High Speed Turning Of Compacted Graphite Iron (Cgi) Using Controlled Modulation, Tyler Paul Stalbaum

Open Access Theses

Compacted graphite iron (CGI) is a material which emerged as a candidate material to replace cast iron (CI) in the automotive industry for engine block castings. Its thermal and mechanical properties allow the CGI-based engines to operate at higher cylinder pressures and temperatures than CI-based engines, allowing for lower fuel emissions and increased fuel economy. However, these same properties together with the thermomechanical wear mode in the CGI-CBN system result in poor machinability and inhibit CGI from seeing wide spread use in the automotive industry.

In industry, machining of CGI is done only at low speeds, less than V = …

Engineering Childhood: Knowledge Transmission Through Parenting, Brianna L. Dorie, Monica Cardella

School of Engineering Education Graduate Student Series

Parents are the front line when it comes to the education and development of their children, and are important agents in the educational achievement of their child in a formal setting (Yun et al, 2010; Catsambis, 1995; Fan & Chen, 2001; Seyfried & Chung,2003). Parents purchase toys, read books, take children to museums, and interact with their child on a daily basis. Particular background with a subject, such as science or engineering, can affect the parent’s strategies for educating their children and subsequent understanding of main concepts (Yun et al., 2010). However, many adults and children alike have a minimal …

Reliability Of The Global Real-Time Assessment Tool For Teaching Enhancement (G-Rate), Nikitha Sambamurthy, Jeremi Shavonda London, Jeeyeon Hahn, Jiabin Zhu, Monica F. Cox

School of Engineering Education Graduate Student Series

In response to the need for research-based assessment tools for effective teaching and to provide feedback to graduate teaching assistants about their instructional interactions in a classroom, the Global Real-time Assessment Tool for Teaching Enhancement (G-RATE) has been developed.The G-RATE has a flexible and easy-to-use interface that allows use in lecture and laboratory environments to collect data from a variety of stakeholders, including undergraduate students,instructors, researchers, and administrators.This paper presents a brief overview of the revised version of the Observer function of the G-RATE (Cox, Hahn, McNeill, Cekic, Zhu, & London, 2011) (Figure 1), which collects real-time classroom data framed …

Microcontrollers For Mechanical Engineers: From Assembly Language To Controller Implementation, Noah Salzman, Peter H. Meckl

School of Engineering Education Graduate Student Series

This paper describes the evolution of a graduate and advanced undergraduate mechanical engineering course on microcontrollers and electromechanical control systems. The course begins with developing an understanding of the architecture of the microcontroller, and low-level programming in assembly language. It then proceeds to working with various functions of the microcontroller, including serial communications, interrupts, analog to digital conversion, and digital to analog conversion. Finally, the students learn how to characterize first and second order systems, and develop and implement their own controllers for a variety of electromechanical systems. The course takes the uncommon approach of teaching assembly language programming to …

The Anisotropic Hyperelastic Biomechanical Response Of The Vocal Ligament And Implications For Frequency Regulation: A Case Study, Jordan E. Kelleher, Thomas Siegmund, Mindy Du, Elhum Naseri, Roger W. Chan

School of Mechanical Engineering Faculty Publications

No abstract provided.

Assessing Student Design Work In Social Entrepreneurship Projects, Lindsey Anne Nelson

School of Engineering Education Graduate Student Series

Helping People Living in Poverty? Understanding Factors Motivating Social Entrepreneurship Abstract Increasingly, engineering educators look to increase the social relevance of engineering design activities. The emergence of social businesses has sparked interest in creating programs that teach engineers about social entrepreneurship. Social businesses are viable business ventures where businesses adopt a social mission. Some strategists view social businesses as ways to capture market share in countries that have a large emerging consumer class, such as India and Brazil. These strategists speak of finding “the fortune at the Bottom of the Pyramid” and target consumers earning less than 4USD/day. Other strategists …

Using Puppets To Elicit Talk During Interviews On Engineering With Young Children, Brianna L. Dorie, Zdanna Tranby, Scott K. Van Cleave, Monica Cardella, Gina Navoa Svarovsky

School of Engineering Education Graduate Student Series

Interviewing can be tricky at best, but with a younger audience (< 5 years) there are some additional barriers that inhibit the interview process such as shyness, short attention span,lack of vocabulary, and level of parental guidance (Clark, 1999). When in an interview, a child may try to ‘second guess’ what the researcher wants them to say, especially if they believe that the interviewer may already know the answer (Gallop, 2000). Additionally young children tend to give monosyllabic answers to open ended questions (Tizard &Hughes, 1984), and might require more prompting than adults.One aide that has been recently investigated is the use of puppets to elicit children’s talk for research (Epstein et al., 2008). Puppets have been shown to: • Decrease children’s fears of the interview process • Lower anxiety levels • Help assess children’s knowledge • Help children to adjust to environment • Provide effective communication and teaching tools. Most research focuses on puppets within clinical contexts, but recently the use has been extended towards other applications such as qualitative interviews (Epstein et al., 2008),mathematical lessons (Cauley, 1988), promoting science engagement (Naylor et al,2007), and teaching phonics (Johnston & Watson, ???). However, there has not been any documented use of this research approach within engineering education.There are three common interview techniques involving puppets in practice: the Alien Puppet Interview (API) (Krott and Nicoladis, 2005), the Puppet Interview (PI) (Cassidy,1988; Verschueren, Buyuk and Marcoen, 2001) and the Berkeley Puppet Interview (BPI) (Measelle et al., 1998; Ablow et al., 1999). Each technique has a different strategy depending on how the child interacts with the puppet.As part of a larger project, children ages 3-5 were interviewed about an engineering task that they had just completed with their parents during a museum event. The interview was a hybrid mix of the Alien Puppet Interview and the Puppet Interview, depending on the way in which the child interviewee chose to interact with the puppet. Thirty interviews were analyzed for children’s interaction, quality of answers, and behavior toward the puppet.In the paper, we will provide more details about the specific interview approach used for our study (as well as insights into how children responded to this interview approach) in addition to a larger discussion of the three interview techniques in order to provide a research methodology resource for other pre-college engineering education researchers to use.

Making The Most Of Site Visits, Lindsey Anne Nelson

School of Engineering Education Graduate Student Series

In order to engage communities, engineering educators must build networks with diverse community organizations. These community organizations primarily act as clients for student design teams. Engineering students are expected to treat clients with respect while developing solutions that solve a real problem found in the community organization. However, engineering students might not view people within the community organization as crucial stakeholders who have valuable information. The purpose of this paper is to explore how engineering students seek information during site visits to community partners.This paper analyzes students in a simulation activity to observe how students interact with different kinds of …

The Dynamics Of Attracting Switchers: A Cross-Disciplinary Comparison, Corey T. Schimpf, George Dante Ricco, Matthew Ohland

School of Engineering Education Graduate Student Series

A Hazards Model Study of Pathway Analysis in Engineering Factors that indicate, explain, or predict if a student will persist or exit an engineering degree have been a subject of a lot of research in engineering education. Findings from these studies identify factors that lead to success or barriers that lead premature exit from an engineering degree; however, they often focus on students who matriculate into engineering or analyze students once they have matriculated into engineering. We propose studying an alternate pathway, students who switch into engineering from other majors. Examining alternate pathways may yield a fuller picture of the …

General Transformations For Gpu Execution Of Tree Traversals, Michael Goldfarb, Youngjoon Jo, Milind Kulkarni

Department of Electrical and Computer Engineering Technical Reports

With the advent of programmer-friendly GPU computing environments, there has been much interest in offloading workloads that can exploit the high degree of parallelism available on modern GPUs. Exploiting this parallelism and optimizing for the GPU memory hierarchy is well-understood for regular applications that operate on dense data structures such as arrays and matrices. However, there has been significantly less work in the area of irregular algorithms and even less so when pointer-based dynamic data structures are involved. Recently, irregular algorithms such as Barnes-Hut and kd-tree traversals have been implemented on GPUs, yielding significant performance gains over CPU implementations. However, …

Mechanical Concrete, Purdue Ect Team

ECT Fact Sheets Archive

Mechanical Concrete® is a way of binding crushed stone aggregates together into a load bearing cellular building unit. The Mechanical Concrete® unit can support compressive loads and resist lateral soil pressure.

Greenpatch® - Cold Mix Asphalt, Purdue Ect Team

ECT Fact Sheets Archive

GreenPatch® is environmentally friendly cold asphalt that is a direct replacement for traditional cold patch in repairing asphalt pavements. This revolutionary breakthrough in the cold asphalt industry contains no petroleum based softeners such as diesel, toluene, kerosene, and naphthalene found in conventional cold asphalt that pose serious threats to human health and the environment.

Tire Log™, Purdue Ect Team

ECT Fact Sheets Archive

The Tire Log™ is a patented innovation made from waste tires with a unique and energy efficient approach to recycling tires. Re-Tread Products (RTP) process takes full advantage of the embedded energy in tires that is wasted in conventional tire recycling that primarily involves the grinding, burying or burning of waste tires.

Bubbledeck, Purdue Ect Team

ECT Fact Sheets Archive

Conventional horizontal concrete slabs are heavy that limit their spans. Enhancement of span results in addition of beams that increases the cost of the structure. Thus, there is a need for a technology that will help in increasing the span by reducing weight of the span. BubbleDeck is a revolutionary construction method that virtually eliminates concrete from the middle of a floor slab between columns that does not perform any structural function, thereby dramatically reducing structural dead weight. BubbleDeck is based on a patented technique - the direct way of linking air and steel.

Thermoelectric Properties Of Epitaxial Scn Films Deposited By Reactive Magnetron Sputtering Onto Mgo(001) Substrates, Polina V. Burmistrova, Jesse Maassen, Tela Favaloro, Bivas Saha, Shuaib Salamat, Yee Rui Koh, Mark S. Lundstrom, Ali Shakouri, Timothy D. Sands

Department of Electrical and Computer Engineering Faculty Publications

Epitaxial ScN(001) thin films were grown on MgO(001) substrates by dc reactive magnetron sputtering.The deposition was performed in an Ar/N2 atmosphere at 2 x 10−3 Torr at a substrate temperature of 850 °C in a high vacuum chamber with a base pressure of 10−8 Torr. In spite of oxygen contamination of 1.6 +/- 1 at. %, the electrical resistivity, electron mobility, and carrier concentration obtained from a typical filmgrown under these conditions by room temperature Hall measurements are 0.22 mΩ cm, 106 cm2 V−1 s−1, and 2.5 x 1020 cm−3, respectively. These films exhibit remarkable thermoelectric power factors of 3.3–3.5 …

A Computational Study Of The Thermoelectric Performance Of Ultrathin Bi2te3 Films, Jesse Maassen, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The ballistic thermoelectric performance of ultrathin films of Bi2Te3, ranging in thickness from 1 to 6 quintuple layers, is analyzed using density functional theory combined with the Landauer approach. Our results show that the thinnest film, corresponding to a single quintuple layer, has an intrinsic advantage originating from the particular shape of its valence band, leading to a large power factor and figure-of-merit exceeding bulk Bi2Te3. The interaction between the top and bottom topological surface states is key. The thinnest film yields a six-fold increase in power factor compared to bulk.

On The Use Of Rau’S Reciprocity To Deduce External Radiative Efficiency In Solar Cells, Xufeng Wang, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Rau’s reciprocity relation has been used to deduce the external radiative efficiency of a wide variety of solar cells using just standard solar cell measurements, but it is based on a number of assumptions, some of which may not be valid for typical thin-film solar cells. In this paper, we use rigorous optical simulations coupled with carrier transport simulations to examine some common thin film solar cells. The results provide guidance on when the Rau relation can be used, why it can fail, and on the magnitude of the errors that can be expected in practice.

Compact Models And The Physics Of Nanoscale Fets, Mark S. Lundstrom, Dimitri A. Antoniadis

Department of Electrical and Computer Engineering Faculty Publications

The device physics of nanoscale MOSFETs is reviewed and related to traditional compact models. Beginning with the Virtual Source model, a model for nanoscale MOSFETs expressed in traditional form, we show how a Landauer approach gives a clear, physical interpretation to the parameters in the model. The analysis shows that transport in the channel is limited by diffusion near the virtual source both below and above threshold, that current saturation is determined by velocity saturation near the source, not by the maximum velocity in the channel, and that the channel resistance approaches a finite value as the channel length approaches …

The Case For Interposed Abdominal Compression Cpr In Hospital Settings, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Interposed abdominal compression (IAC)-CPR includes all steps of standard external CPR with the addition of manual mid-abdominal compressions in counterpoint to the rhythm of chest compressions. IAC-CPR can increase blood flow during CPR about two fold compared to standard CPR without IAC, as shown by multiple studies in computer and animal models. The technique increases the rate return of spontaneous circulation (ROSC) for in-hospital resuscitations from roughly 25% to 50%. Improved survival to discharge is demonstrated in two in-hospital trials. IAC as an adjunct technique is quickly taught and is less complex than most other basic life support maneuvers. A …

Theoretical Foundations For Effective Stem Learning Environments, Aran W. Glancy, Tamara J. Moore

School of Engineering Education Working Papers

No abstract provided.

Pre-Breakdown Evaluation Of Gas Discharge Mechanisms In Microgaps, Abbas Semnani, Ayyaswamy Venkattraman, Alina A. Alexeenko, Dimitrios Peroulis

School of Aeronautics and Astronautics Faculty Publications

The individual contributions of various gas discharge mechanisms to total pre-breakdown current in microgaps are quantified numerically. The variation of contributions of field emission and secondary electron emission with increasing electric field shows contrasting behavior even for a given gap size. The total current near breakdown decreases rapidly with gap size indicating that microscale discharges operate in a high-current, low-voltage regime. This study provides the first such analysis of breakdown mechanisms and aids in the formulation of physics-based theories for microscale breakdown

Frequency Response Of Atmospheric Pressure Gas Breakdown In Micro/Nanogaps, Abbas Semnani, Ayyaswamy Venkattraman, Alina A. Alexeenko, Dimitrios Peroulis

School of Aeronautics and Astronautics Faculty Publications

In this paper, we study gas breakdown in micro/nanogaps at atmospheric pressure from low RF to high millimeter band. For gaps larger than about 10 lm, the breakdown voltage agrees with macroscale vacuum experiments, exhibiting a sharp decrease at a critical frequency, due to transition between the boundary- and diffusion-controlled regimes, and a gradual increase at very high frequencies as a result of inefficient energy transfer by field. For sub-micron gaps, a much lower breakdown is obtained almost independent of frequency because of the dominance of field emission

Suppressing Leakage By Localized Doping In Si Nanotransistor Channels, Jesse Maassen, Hong Guo

Birck and NCN Publications

By first principles atomistic analysis we demonstrate how controlled localized doping distributions in nanoscale Si transistors can suppress leakage currents. We consider dopants (B and P atoms) to be randomly confined to a approximate to 1 nmwidth doping region in the channel. If this region is located away from the electrodes, roughly 20% of the channel length L, the tunneling leakage is reduced 2x compared to the case of uniform doping and shows little variation. Oppositely, we find the leakage current increases by orders of magnitude and may result in large device variability. We calculate the maximum and minimum conductance …

Real Time X-Ray Studies During Nanostructure Formation On Silicon Via Low Energy Ion Beam Irradiation Using Ultrathin Iron Films, Osman El-Atwani, Anastassiya Suslova, Alexander Demasi, Sean Gonderman, Justin Fowler, Mohamad El-Atwani, Karl Ludwig, Jean Paul Allain

Birck and NCN Publications

Real time grazing incidence small angle x-ray scattering and x-ray fluorescence (XRF) are used to elucidate nanodot formation on silicon surfaces during low energy ion beam irradiation of ultrathin iron-coated silicon substrates. Four surface modification stages were identified: (1) surface roughening due to film erosion, (2) surface smoothing and silicon-iron mixing, (3) structure formation, and (4) structure smoothing. The results conclude that 2.5 x 10(15) iron atoms in a 50 nm depth triggers surface nanopatterning with a correlated nanodots distance of 25 nm. Moreover, there is a wide window in time where the surface can have correlated nanostructures even after …