Engineering Commons^™

An Intelligent Computational Approach To The Optimization Of Inventory Policies For Single Company, Qinglin Duan

LSU Master's Theses

This study develops and tests a computational approach for determining optimal inventory policies for single company. The computational approach generally comprises of two major components: a meta-heuristic optimizer and an event-driven inventory evaluation module. Meta-heuristic is a powerful search technique, under the intelligent computational paradigm. The approach is capable of determining optimal inventory policy under various demand patterns regardless their distribution for a variety of inventory items. Two prototypes of perishability are considered: (1) sudden deaths due to disasters and (2) outdating due to expirations. Since every theoretical model is specially designed for a certain type of inventory problem while …

A Basic Understanding Of Rapid Mold Surface Heating Via Laser Energy, Charles Daniel Fox

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As the research and development of surface heating methods have increased in the recent years, the consensus has been reached amongst the injection molding community that an elevated mold surface temperature near or greater than the polymer solidification temperature provides acceptable replication of the desired micro-structured parts. The laser heating experimental work and simulation development carried out includes two sample sizes similar to those used in injection molding. A 100W CO2 laser incident on three samples of different surface roughnesses has shown to have elevated temperatures via thermal cameral data and thermocouple measurements. Among five different laser spot sizes varying …

Nano-Scale Rf/Microwave Characterization Of Materials' Electromagnetic Properties, Joshua Allen Myers

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There are two words that describe the direction of today's electronic technology, smaller and faster. With the ever decreeing size scientists and engineers must have a way to characterize materials in the nm range. In this thesis characterization of nano-materials is discussed based on scanning probe microscopy and an in-depth look at RF/microwave frequencies by scanning microwave microscopy. Recently, low-temperature spin-sprayed ferrite films (Fe3O4) with a high self-biased magnetic anisotropy field have been reported, showing FMR frequency>5 GHz. Such films hold great potential for RF/microwave devices and find immediate applications. In this study, we performed in situ scanning microwave …

Optimization Of Wsu Total Ankle Replacement Systems, Bradley Jay Elliott

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Total ankle arthroplasty (TAR) is performed in order to reduce the pain and loss of ambulation in patients with various forms of arthritis and trauma. Although replacement devices fail by a number of mechanisms, wear in the polyethylene liner constitutes one of the dominating failure modes. This leads to instability and loosening of the implant. Mechanisms that contribute to wear in the liners are high contact and subsurface stresses that break down the material over time. Therefore, it is important to understand the gait that generates these stresses. Methods to characterize and decrease wear in Ohio TARs have been performed …

Computational Investigation Of A Hinge-Connected Hovering Plate, Zachary Robert Gaston

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A simplified conceptual flapping wing MAV design, capable of hover, is formed from the works of both biologists and engineers, studying the behavior of flying insects and the aerodynamics of flapping flight. With this new model, hovering hinged plates are used to study the effects of passive deflection on aerodynamic performance using two-dimensional Direct Numerical Simulations (DNS) at low Reynolds numbers (Re). The hinge is modeled as a torsional spring at the leading edge, where prescribed motion is applied. The influence of forced-to-natural frequency ratio (hinge stiffness) and stroke-to-chord ratio (leading edge kinematics) are studied, to explore the effects that …

Human Action Recognition By Principal Component Analysis Of Motion Curves, Daniel Stephen Chivers

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Human action recognition is used to automatically detect and recognize actions per- formed by humans in a video. Applications include visual surveillance, human-computer interaction, and robot intelligence, to name a few. An example of a surveillance application is a system that monitors a large public area, such as an airport, for suspicious activity. In human-machine interaction, computers may be controlled by simple human actions. For example, the motion of an arm may instruct the computer to rotate a 3-D model that is being displayed. Human action recognition is also an important capability of intelligent robots that interact with humans.

General …

Extreme Strain Localization And Sliding Friction In Physically Associating Polymer Gels, Kendra Erk, Jeffrey D. Martin, Y. Thomas Hu, Kenneth R. Shull

School of Materials Engineering Faculty Publications

Model physically associating gels deformed in shear over a wide range of reduced rates displayed evidence of strain localization. The non-linear stress responses and inhomogeneous velocity profiles observed during shear rheometry coupled with particle tracking velocimetry were associated with the occurrence of rate-dependent, banding and fracture-like responses in the gel. Scaling law analysis from traditional sliding friction studies suggests that at the molecular level, deformation is confined to a shear zone with thickness comparable to the gel’s mesh size, the smallest structurally relevant length scale in the gel.

Sectionality Or Why Section Determines Grades: An Exploration Of Engineering Core Course Section Grades Using A Hierarchical Linear Model And The Multiple-Institution Database For Investigating Engineering Longitudinal Development, George Dante Ricco, Noah Salzman, Russell A. Long, Matthew Ohland

School of Engineering Education Graduate Student Series

No abstract provided.

Low-Ses First-Generation Students’ Decision To Pursue Engineering, Michele L. Strutz, Matthew Ohland

School of Engineering Education Graduate Student Series

The ability of this nation to provide a growing economy, strong health and human services, and a secure and safe nation depends upon a vibrant, creative, and diverse engineering and science workforce” (Blue, et al., 2005, p. 4). To address these global opportunities and challenges, and for the U.S. to remain globally competitive, it is necessary for our engineering workforce to be diverse.Nevertheless, the U.S. cannot claim a diverse engineering workforce, and its engineering student bodies are certainly not diverse despite the legislation and programs put in place to increase racial, gender, and socioeconomic (SES) representation. Programs and resources that …

Exploring Cyberlearning Through A Nsf Lens, Jeremi Shavonda London

School of Engineering Education Graduate Student Series

Phrases like “Let’s Google it” and “Text me” are familiar to the youth of today. Though simple, the phrases speak to a greater reality—the use of computing technology and high-speed communication is ubiquitous. The pervasive use of technology opens up new opportunities for undergraduate STEM education. The NSF Task force on Cyberlearning defines cyberlearning as“the use of networked computing and communications technologies to support learning” (2008,p5). Since the full potential of cyberlearning has not been fully realized in undergraduate education, Program Officers in the Division of Undergraduate Education (DUE) at the National Science Foundation (NSF) are interested in exploring the …

Measuring Undergraduate Student Perceptions Of The Impact Of Project Lead The Way, Noah Salzman, Eric L. Mann, Matthew Ohland

School of Engineering Education Graduate Student Series

A survey was distributed to the entire undergraduate student body at a large public university on students’ experiences in Project Lead The Way, a popular middle school and high school technology and engineering program. The survey included demographic questions including academic major, questions on which PLTW classes the students took in high school, and Likert-type ratings of those experiences.Of the responses to the survey (n=575), slightly fewer than half (n=252) indicated that they had participated in PLTW classes in high school. Approximately half of the respondents were majoring in engineering, one quarter in engineering technology, and the rest were distributed …

Scaffolding Undergraduate Engineering Design Education With The Wellbeing Framework, Lindsey Anne Nelson

School of Engineering Education Graduate Student Series

Increasingly, engineering design educators articulate wanting to embed social sustainability into student projects. Some educators observe that global calls, such as the Grand Challenges of Engineering and the Millennium Development Goals, foster social consciousness while supporting open innovation environments. Using a broad social goal like “poverty alleviation” to frame a course design challenge can help students connect engineering design processes to messages that proclaim engineering as a socially engaged profession [1]. Yet scaffolding student learning in engineering design for poverty alleviation should involve more than a simple directive to create a device for a poor person. The purpose of this …

Direct Measurements And Numerical Simulations Of Gas Charging In Microelectromechanical System Capacitive Switches, A Venkattraman, A Garg, D Peroulis, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

Gas breakdown in microelectromechanical system capacitive switches is demonstrated using high resolution current measurements and by particle-in-cell/Monte Carlo collision (PIC/MCC) simulations. Measurements show an electric current through a 3 μm air gap increasing exponentially with voltage, starting at 60 V. PIC/MCC simulations with Fowler-Nordheim [Proc. R. Soc. London, Ser. A 119, 173 (1928)] field emission reveal self-sustained discharges with significant ion enhancement and a positive space charge. The effective ion-enhanced field emission coefficient increases with voltage up to about 0.3 with an electron avalanche occurring at 159 V. The measurements and simulations demonstrate a charging mechanism for microswitches …

A Comparative Study Of No-Time-Counter And Majorant Collision Frequency Numerical Schemes In Dsmc, A Venkattraman, Alina A. Alexeenko, M A. Gallis, M S. Ivanov

School of Aeronautics and Astronautics Faculty Publications

The direct simulation Monte Carlo (DSMC) method is a stochastic approach to solve the Boltzmann equation and is built on various numerical schemes for transport, collision and sampling. This work aims to compare and contrast two popular O(N) DSMC collision schemes - no-time-counter (NTC) and majorant collision frequency (MCF) - with the goal of identifying the fundamental differences. MCF and NTC schemes are used in DSMC simulations of a spatially homogeneous equilibrium gas to study convergence with respect to various collision parameters. While the MCF scheme forces the reproduction of the exponential distribution of time between collisions, …

Scaling Law For Direct Current Field Emission-Driven Microscale Gas Breakdown, A Venkattraman, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

The effects of field emission on direct current breakdown in microscale gaps filled with an ambient neutral gas are studied numerically and analytically. Fundamental numerical experiments using the particle-in-cell/Monte Carlo collisions method are used to systematically quantify microscale ionization and space-charge enhancement of field emission. The numerical experiments are then used to validate a scaling law for the modified Paschen curve that bridges field emission-driven breakdown with the macroscale Paschen law. Analytical expressions are derived for the increase in cathode electric field, total steady state current density, and the ion-enhancement coefficient including a new breakdown criterion. It also includes the …

Assessment Of High-Enthalpy Air Chemistry Models For Hypervelocity Ground-Based Experiments, Marat Kulakhmetov, Yevgeniy A. Bondar, Mikhail S. Ivanov, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

Hypersonic vehicles re-entering Earth's atmosphere with orbital velocities generate gas flows with significant thermo-chemical non-equilibrium. Detailed kinetics of chemical reactions at such conditions is still not well understood but it may affect vehicle's thermal loads, aerodynamic moments and thermal radiation. This work assesses the Total Collision Energy (TCE) and the Kuznetsov-based state specific (KSS) chemical reaction models at pressures between 1 and 50 torr and velocities between 4 and 10 km/s in order to identify best test conditions for validating the models. Hypersonic flows at such conditions can be studied at the hypervelocity impact range facilities.

A Runge-Kutta Discontinuous Galerkin Solver For 2d Boltzmann Model Equations: Verification And Analysis Of Computational Performance, Wei Su, Alina A. Alexeenko, Guobiao Cai

School of Aeronautics and Astronautics Faculty Publications

The high-order Runge-Kutta discontinuous Galerkin (DG) method is extended to the 2D kinetic model equations describing rarefied gas flows. A DG-type discretization of the equilibrium velocity distributions is formulated for the Bhatnagar-Gross-Krook and ellipsoidal statistical models which enforce a weak conservation of mass, momentum and energy in the collision relaxation term. The RKDG solutions have up to 3^rd-order spatial accuracy and up to 4^th-order time accuracy. Verification is carried out for a steady 1D Couette flow and a 2D thermal conduction problem by comparison with DSMC and analytical solutions. The computational performance of the RKDG method …

Pvc Stay-In-Place Panel Covers For Tilt-Up And Pre-Cast Construction, Purdue Ect Team

ECT Fact Sheets Archive

Octaform™ stay-in-place concrete forming system is PVC insulated concrete form system. These forms have been used in the industry for various applications to improve the insulation and corrosion resistance of structures. Octaform™ has developed the panel covers so the advantages of PVC stay-in-place concrete forming systems could be applied to tilt-up and pre-cast construction.

Conx Chassis System, Purdue Ect Team

ECT Fact Sheets Archive

Often referred to as a full-scale “Erector Set”, the ConX System applies technology to the building industry resulting in dramatic efficiencies. The systems approach is made possible by employing automated and efficient processes, from design through fabrication, shipping, and field assembly.

Nightbreeze™: Integrated Heating, Ventilation And Cooling System, Purdue Ect Team

ECT Fact Sheets Archive

NightBreeze™ provides ventilation cooling automatically, eliminating the necessity of operating windows. NightBreeze™ uses the heating/air conditioning system fan to bring in filtered outside air and flush out warm, stale indoor air. The system also allows you to select the lowest temperature you want the house to reach overnight.

Cmic Xprojects, Purdue Ect Team

ECT Fact Sheets Archive

xProjects is a cloud based collaboration and project management solution that resolves the interoperability issues associated with integrated project delivery (IPD) and electrifies the IPD process by enabling capital project owners to collaborate seamlessly with multiple project stakeholders. Using XML adapters to create connections between systems, CMiC Real Time Integration (RTI) tags data so it can be transferred bi-directionally between participants within the project ecosystem with no loss of information or the need for re-entry.

Autodesk Buzzsaw®, Purdue Ect Team

ECT Fact Sheets Archive

Autodesk® Buzzsaw® is a software solution enabling the successful execution of construction projects through a central database, collaboration and communication with access control. The software has capacities of exchanging and viewing drawings, schedule reminders and specifications. Users can directly comment on AutoCAD drawings with the date of comment and name of commenter displayed.

Bidtool.Net: An Integrated Web-Based Approach For Commercial Bid Data Management And Networking, Purdue Ect Team

ECT Fact Sheets Archive

BidTool is basically a web-based portal that allows the distribution and transfer of key commercial construction project data. Owners, architects, designers, engineers, estimators, contractors, material suppliers & construction professionals find track and manage everything from architectural plans specifications and renderings to action items and scheduling requirements such as bid due dates, pre bid meetings and bid results.

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 …