Engineering Commons^™

Contour Crafting, Purdue Ect Team

ECT Fact Sheets Archive

Victims of disasters such as floods, earthquakes and war have to seek shelter elsewhere. A need arises to rapidly construct houses on site and at minimal cost. This will eliminate the need to transport pre-fabricated shelters long distances, saving the time and costs associated with transportation. Since Contour Crafting is an automated process, labor needs are highly minimized allowing relief workers to allocate their time and effort to rebuilding local infrastructure such as water sanitation and distribution systems, roads, electrical and communication systems as well as irrigations systems.

Super Flex Wall - New Frame System For High Rise Buildings, Purdue Ect Team

ECT Fact Sheets Archive

The "Super Flex Wall" is a structural frame method newly developed by the Takenaka Corporation, used in combination with a core wall (the earthquake-resistant reinforced concrete wall penetrating through the center of the building from the lower part to the top floor) and a structural control method or with a base-isolation method. Part of the structure is cantilevered from the central core along the periphery of the building.

Carbon Frp Grid Structures For Use In Reinforcing Concrete, Purdue Ect Team

ECT Fact Sheets Archive

Carbon FRP Grids are structural reinforcement materials that improve the performance of concrete structures such as insulated wall panels, architectural panels, double tee parking garage tee beams, concrete countertops and other products. The carbon grids can be used in place of welded wire mesh in most structures and is imbedded the same way as a welded wire mesh.

Conx Space Frame System, Purdue Ect Team

ECT Fact Sheets Archive

Off-site manufacture is one of the key initiatives being used by contractors to achieve these goals. Sandwich Plate System (SPS) Floors deliver a compelling off-site solution for structural floors. Their composite steel panels provide a similar performance to concrete floors at one quarter the weight, 10 - 15% shorter project schedules and broader benefits such as reduced complexity and the elimination of the majority of wet-work above ground level.

Can Morphology Tailoring Improve The Open Circuit Voltage Of Organic Solar Cells?, Biswajit Ray, Mark S. Lundstrom, Muhammad A. Alam

Department of Electrical and Computer Engineering Faculty Publications

While the effect of interfacial morphology on the short circuit current (ISC) of organic photovoltaic devices (OPVs) is well known, its impact on open circuit voltage (VOC) and fill-factor (FF) are less clear. Since the output power of a solar cell Pout 1/4 ISCVOCFF, such understanding is critical for designing high-performance, morphology-engineered OPVs. In this letter, we provide an explicit analytical proof that any effort to radically improve VOC by tailoring bulk heterojunction morphology is futile, because any increase in ISC due to larger interface area is counterbalanced by corresponding increase in recombination current, so that the upper limit of …

Thermal Conductivity Of Bulk And Thin-Film Silicon: A Landauer Approach, Changwook Jeong, Supriyo Datta, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The question of what fraction of the total heat flow is transported by phonons with different mean-free-paths is addressed using a Landauer approach with a full dispersion description of phonons to evaluate the thermal conductivities of bulk and thin film silicon. For bulk Si, the results reproduce those of a recent molecular dynamic treatment showing that about 50% of the heat conduction is carried by phonons with a mean-free-path greater than about 1 μm. For the in-plane thermal conductivity of thin Si films, we find that about 50% of the heat is carried by phonons with mean-free-paths shorter …

Computational Study Of Energy Filtering Effects In One-Dimensional Composite Nano-Structures, Raseong Kim, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Possibilities to improve the Seebeck coefficient S versus electrical conductance G trade-off of diffusive composite nano-structures are explored using an electro-thermal simulation framework based on the non-equilibrium Green’s function method for quantum electron transport and the lattice heat diffusion equation. We examine the role of the grain size d, potential barrier height UB, grain doping, and the lattice thermal conductivity jL using a one-dimensional model structure. For a uniform jL, simulation results show that the power factor of a composite structure may be improved over bulk with the optimum UB being about kBT, where kB and T are the Boltzmann …

On The Best Bandstructure For Thermoelectric Performance: A Landauer Perspective, Changwook Jeong, Raseong Kim, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The question of what bandstructure produces the best thermoelectric device performance is revisited from a Landauer perspective. We find that a delta-function transport distribution function (TDF) results in operation at the Mahan-Sofo upper limit for the thermoelectric figure-of-merit, ZT. We show, however, the Mahan-Sofo upper limit itself depends on the bandwidth (BW) of the dispersion, and therefore, a finite BW dispersion produces a higher ZT when the lattice thermal conductivity is finite. Including a realistic model for scattering profoundly changes the results. Instead of a narrow band, we find that a broad BW is best. The prospects of increasing ZT …

Predicting Success Or Failure Of Immunotherapy For Cancer: Insights From A Clinically Applicable Mathematical Model, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The objective of this study was to create a clinically applicable mathematical model of immunotherapy for cancer and use it to explore differences between successful and unsuccessful treatment scenarios. The simplified predator-prey model includes four lumped parameters: tumor growth rate, g; immune cell killing efficiency, k; immune cell signaling factor, λ; and immune cell half-life decay, μ. The predator-prey equations as functions of time, t, for normalized tumor cell numbers, y, (the prey) and immunocyte numbers, x, (the predators) are: dy/dt = gy – kx and dx/dt = λxy – μx. A parameter estimation procedure that capitalizes on available clinical …

Optimizing Electrode Placement For Hemodynamic Benefit In Cardiac Resynchronization Therapy, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Background: Research is needed to explore the relative benefits of alternative electrode placements in biventricular and left ventricular pacing for heart failure with left bundle branch block (LBBB). Methods: A fast computational model of the left ventricle, running on an ordinary laptop computer, was created to simulate the spread of electrical activation over the myocardial surface, together with the resulting electrocardiogram, segmental wall motion, stroke volume, and ejection fraction in the presence of varying degrees of mitral regurgitation. Arbitrary zones of scar and blocked electrical conduction could be modeled. Results: Simulations showed there are both sweet spots and poor spots …

Climatic Effects Of The Chicxulub Impact Ejecta, Devon Parkos, Marat Kulakhmetov, Brandon Johnson, Henry J. Melosh, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

Examining the short and long term effects of the Chicxulub impact is critical for understanding how life developed on Earth. While the aftermath of the initial impact would have produced harmful levels of radiation sufficient for eradicating a large portion of terrestrial life, this process does not explain the concurrent marine extinction. Following the primary impact, a large quantity of smaller spherules would de-orbit and re-enter the earths atmosphere, dispersed nearly uniformly across the planet. This secondary wave of debris would re-enter at high velocities, altering the chemical composition of the atmosphere. Furthermore, the combined surface area for the spherules …

An Analysis Of Step, Jt, And Pdf Format Translation Between Constraint-Based Cad Systems With A Benchmark Model, Dillon Mckenzie-Veal

Department of Computer Graphics Technology Degree Theses

This research was conducted to provide greater depth into the ability of STEP AP 203 Edition 2, JT, and 3D PDF to translate and preserve information while using a benchmark model. The benchmark model was designed based on four industry models and created natively in the five industry leading 3D CAD programs. The native CAD program models were translated using STEP, JT, and 3D PDF. Several criteria were analyzed along the paths of translation from one disparate CAD program to another. Along with the analysis of the three interoperable file formats a survey was conducted to determine how well the …

Evaluating Net-Zero Energy Houses From The U.S. Department Of Energy Solar Decathlon 2011, Jordan P. Wallpe, William J. Hutzel, Gregory Lasker, Clark Cory

School of Engineering Technology Faculty Publications

The Solar Decathlon is a two year, international project where university students compete to design, build, and test energy-efficient, net-zero homes. By definition, net-zero energy houses annually produce as much electricity as they consume. The 2011 Solar Decathlon, held in Washington D.C., had 19 university teams from around the world.

Unfortunately, many past Solar Decathlon houses have traditionally been very costly. However, the 2011 Solar Decathlon was the first competition to have an affordability contest. The affordability contest required each home to be valued under an estimated builder’s cost of $250,000, forcing the teams to select economically feasible solutions for …

Knowledge-Enabled Engineering Design: Toward An Integrated Model, Michael Fosmire, David Radcliffe

Libraries Faculty and Staff Scholarship and Research

Librarians and engineering faculty have long understood that design is one of the defining processes of the engineering profession. In an increasingly knowledge-driven society, students need to efficiently locate, assess and integrate relevant information into their design process so that they can develop innovation solutions to emerging complex, global grand challenges. Increasingly, engineering curricula are incorporating design as early as the first year, but a question remains as to how effectively information literacy is being integrated into these early experiences of design. For example, the Engineering Change study found there has been very little improvement to lifelong learning skills in …

Shear And Dilational Interfacial Rheology Of Surfactant-Stabilized Droplets, Kendra Erk, Jeffrey D. Martin, Jonathan T. Schwalbe, Frederick R. Phelan Jr., Steven D. Hudson

School of Materials Engineering Faculty Publications

A new measurement method is suggested that is capable of probing the shear and dilational interfacial rheological responses of small droplets, those of size comparable to real emulsion applications. Freely suspended aqueous droplets containing surfactant and non-surface-active tracer particles are transported through a rectangular microchannel by the plane Poiseuille flow of the continuous oil phase. Optical microscopy and high-speed imaging record the shape and internal circulation dynamics of the droplets. Measured circulation velocities are coupled with theoretical descriptions of the droplet dynamics in order to determine the viscous (Boussinesq) and elastic (Marangoni) interfacial effects. A new Marangoni-induced stagnation point is …

A Study Of Field Emission Process In Electrostatically Actuated Mems Switches, L Michalas, A Garg, A Venkattraman, M Koutsoureli, Alina A. Alexeenko, Dimitrios Peroulis, G Papaioannou

School of Aeronautics and Astronautics Faculty Publications

A study of field emission process in MEMS-based capacitor/switch-like geometries is presented. High resolution current-voltage characteristics up to breakdown have been obtained across micro-gaps in fixed-fixed Metal-Air- Metal and Metal-Air-Insulator-Metal structures. In metallic devices the I-V dependence reveals Fowler –Nordheim theory effects. In the presence of insulator the process is found to be limited by the film conductivity following Poole –Frenkel dependence. The data analysis reveals the major importance of surface asperities on the onset of the field emission process while it is also presented that charge transfer may occur between metal and insulator surfaces even in the presence of …

Nonlinear Effects In Squeeze Film Gas Damping On Microbeams, S Chigullapalli, A Weaver, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

We consider squeeze film gas damping during microbeam motion away and toward a substrate as occurs during opening and closing of RF switches and other MEMS devices. The numerical solution of the gas damping problem in two-dimensional geometries is obtained based on the Boltzmann-ESBGK equation. The difference in damping force between downward and upward moving beams is shown to vary from as little from as 5% for low beam velocities of 0.1m/s to more than 200% at 2.4m/s. For a constant velocity magnitude of 0.8m/s, this difference increases from 60% to almost 90% when the pressure is reduced by an …

Immersed Boundary Method For Boltzmann Model Kinetic Equations, Cem Pekardan, Sruti Chigullapalli, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

Three different immersed boundary method formulations are presented for Boltzmann model kinetic equations such as Bhatnagar-Gross-Krook (BGK) and Ellipsoidal statistical Bhatnagar-Gross-Krook (ESBGK) model equations. 1D unsteady IBM solution for a moving piston is compared with the DSMC results and 2D quasi-steady microscale gas damping solutions are verified by a conformal finite volume method solver. Transient analysis for a sinusoidally moving beam is also carried out for the different pressure conditions (1 atm, 0.1 atm and 0.01 atm) corresponding to Kn=0.05,0.5 and 5. Interrelaxation method (Method 2) is shown to provide a faster convergence as compared to the traditional interpolation scheme …

Binary Scattering Model For Lennard-Jones Potential: Transport Coefficients And Collision Integrals For Non-Equilibrium Gas Flow Simulations, Ayyaswamy Venkattraman, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

A Lennard-Jones (LJ) binary interaction model for dilute gases is obtained by representing the exact scattering angle as a polynomial expansion in non-dimensional collision variables. Rigorous theoretical verification of the model is performed by comparison with exact values of diffusion and viscosity cross sections and related collision integrals. The collision quantities given by the polynomial approximation model agree within 3.5% with those of the exact LJ scattering. The proposed model is compared in detail with the generalized soft sphere (GSS) model which is the closest in terms of fidelity among existing direct simulation Monte Carlo collision models. The GSS model's …

Resolving Structure And Mechanical Properties At The Nanoscale Of Viruses With Frequency Modulation Atomic Force Microscopy, David Martinez-Martin, Carolina Carrasco, Mercedes Hernando-Pérez, P. J. De Pablo, Júlio Gómez-Herrero, Rebeca Pérez, Mauricio Garcia Mateu, José López Carrascosa, Daniel Roy Kiracofe, John C. Melcher, Arvind Raman

School of Mechanical Engineering Faculty Publications

Structural Biology (SB) techniques are particularly successful in solving virus structures. Taking advantage of the symmetries, a heavy averaging on the data of a large number of specimens, results in an accurate determination of the structure of the sample. However, these techniques do not provide true single molecule information of viruses in physiological conditions. To answer many fundamental questions about the quickly expanding physical virology it is important to develop techniques with the capability to reach nanometer scale resolution on both structure and physical properties of individual molecules in physiological conditions. Atomic force microscopy (AFM) fulfills these requirements providing images …

A Retrospective Study Of The Elementary School Experiences, Influences, Skills, And Traits Of Talented Engineers, Michele L. Strutz

School of Engineering Education Graduate Student Series

No abstract provided.

Access And Definition: Exploring How Stem Faculty, Department Heads, And University Policy Administrators Navigate The Implementation Of A Parental Leave Policy, Corey T. Schimpf, Marisol Mercado Santiago, Alice L. Pawley

School of Engineering Education Graduate Student Series

Access and Definition: Exploring how STEM Faculty, Department Heads and University Policy Administrators Navigate the Enactment of a Parental Leave Policy A key feature in various reports exploring women’s persisting underrepresentation in STEM faculty positions in the US is the need to disseminate policy information to all stakeholders involved in issues relating to women STEM faculty underrepresentation and retention. Indeed, the National Academies of Science Beyond Barriers and Bias: Fulfilling the Potential of Women Academic Science and Engineering (2007) and the AAUW’s Why so Few?(2010) identify institutional policies, like parental leave, as a way to address an outmoded institutional structure …

Geometrical Frustration In Nanowire Growth, K. W. Schwarz, J. Tersoff, S. Kodambaka, Y.C. Chou, F. M. Ross

Birck and NCN Publications

Idealized nanowire geometries assume stable sidewalls at right angles to the growth front. Here we report growth simulations that include a mix of nonorthogonal facet orientations, as for Au-catalyzed Si. We compare these with in situ microscopy observations, finding striking correspondences. In both experiments and simulations, there are distinct growth modes that accommodate the lack of right angles in different ways-one through sawtooth-textured sidewalls, the other through a growth front at an angle to the growth axis. Small changes in conditions can reversibly switch the growth between modes. The fundamental differences between these modes have important implications for control of …

Construction Of Mse Wall Using Tire Shred-Sand Mixture As Backfill (Spr-3470), Monica Prezzi, Varenya Kumar Duvvuru Mohan

JTRP Other Publications and Reports

A large number of waste tires are generated each year throughout the world. Instead of disposing these tires in landfills, they can be used beneficially in road construction, MSE walls or structural fills that require large quantities of material. Such use of tires not only saves the costs of landfilling, but also provides certain desirable mechanical properties. The focus of this research was on determining important geotechnical properties of tire shred-sand mixtures required for their use as a lightweight backfill for MSE walls. Accordingly, the shear strength and pullout characteristics of tire shred-sand mixtures at various mixing ratios were determined …

Lithium-Based Battery System Management And Balancing, William Joel Schmidt Iii

Purdue Polytechnic Masters Theses

This thesis builds upon previous work completed for the design and evaluation of active lithium battery system management. Simulations were performed to provide a comparison for the hardware that was designed, built, and tested. An analysis of the simulation and hardware results was completed to support or disprove the initial hypothesis. A DC-DC converter was used as the source for the balancing current. Lithium polymer batteries with a 5Ah capacity were used for testing the designed hardware. The findings showed that there is a reduction in the system voltage swing during balancing as well as less time taken to decrease …

Utilizing Technology To Increase The Recycled Content Of Asphalt Mix Designs, Nicholas Ricketts

Purdue Polytechnic Masters Theses

This directed project examined the idea that increasing the amount of recycled asphalt product in road construction will result in a comparable performance to the current levels of recycled asphalt product in today’s pavement. A critical review of literature is structured in four areas: describing the need (financial and environmental) for the increased use of recycled materials, describing how others have addressed the issue and technology needed for increasing the use of recycled content, describing how some contractors have created the technology needed, and finally describing the direction needed in order to encourage customers and government agencies to embrace the …

On The Accuracy Of Classical And Long Wavelength Approximations For Phonon Transport In Graphene, Dhruv Singh, Jayathi Murthy, Timothy S. Fisher

Birck and NCN Publications

This paper presents a critical evaluation of the approximations usually made in thermal conductivity modeling applied to graphene. The baseline for comparison is thermal conductivity computations performed using a rigorous calculation of three-phonon scattering events and accounting for the anharmonicity of interatomic forces. Three central assumptions that underlie published theories are evaluated and shown to compromise the accuracy of thermal conductivity predictions. It is shown that the use of classical phonon occupation statistics in place of the Bose-Einstein distribution causes the overprediction of specific heat and the underprediction of phonon relaxation time; for ZA phonons, the classical approximation can underpredict …

W.E. Bowers Ans Associates, Inc. Financial Operations Manual For Construction Cost Accounting, Stephen E. Brown

Purdue Polytechnic Masters Theses

W.E. Bowers and Associates, Inc. typically hires experienced project managers eager to

diversify their work experience. W.E. Bowers and Associates, Inc. verbally instructs

project managers to properly utilize the companies forms and the processes for financial

management of projects. The verbal training typically occurs in a piecemeal fashion. It

occurs only when a new project manager asks

“How To” perform specific tasks. The

project managers all come with different backgrounds and with different backgrounds,

come different business management strategies. The creation of this financial operations

manual will aid in the training of project managers and provide the company with a …

Engaging New Partners In Transportation Research: Integrating Publishing, Archiving, And Indexing Of Technical Literature Into The Research Process, Mark P. Newton, Darcy M. Bullock, Charles Watkinson, Paul J. Bracke, Deborah K. Horton

Libraries Research Publications

transportation research. The United States Department of Transportation (USDOT) annually invests approximately $180 million in State Planning and Research (SPR) and University Transportation Centers (UTC). This investment generates an extensive portfolio of “grey literature” that is not yet uniformly cataloged or accessible, despite the best efforts of the National Technical Information Service, the Transportation Research Board, and the National Transportation Library. This paper reports on a review of publishing and archiving practices for transportation research technical reports, summarizes best practices, and recommends that UTC and SPR research programs seek and strengthen partnerships with libraries to facilitate improved production, stewardship and …

Electronic Structure Of Realistically Extended Atomistically Resolved Disordered Si:P Delta-Doped Layers, Sunhee Lee, Hoon Ryu, Lloyd Hollenberg, Michelle Simmons, Gerhard Klimeck

Birck and NCN Publications

The emergence of scanning tunneling microscope (STM) lithography and low temperature molecular beam epitaxy (MBE) opens the possibility of creating scalable donor based quantum computing architectures. In particular, atomically precise Si:P monolayer structures (delta-doped layers) serve as crucial contact regions and in-plane gates in single impurity devices. In this paper we study highly confined delta-doped layers to explain the disorder in the P dopant placements in realistically extended systems. The band structure is computed using the tight-binding formalism and charge-potential self-consistency. The exchange-correlation corrected impurity potential pulls down subbands below the silicon valley minima to create impurity bands. Our methodology …