Engineering Science and Materials Commons^™

Rapid Grain Boundary Mobility At Ambient Temperatures, Jarrod M. Lund, R Adam Bilodeau, Rebecca K. Kramer

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding and measuring the influence of grain boundaries (planar defects in the crystalline structure of materials) and their motion has become a dominant aspect in materials research, with applications in additive manufacturing, fatigue prevention, and material modeling. However, modeling grain boundaries and grain boundary mobility (GBM) is difficult due to the high temperatures or external stresses, imaging solutions compatible with the material system, and long time-scales required to create measurable experimental results. In this paper, we introduce a novel material system that allows for easy and fast visualization of GBM. A drop of liquid metal eutectic gallium indium (eGaIn) placed …

Characterization Of Suspension Polymerized Polyacrylamide And Poly(Sodium Acrylate-Acrylamide) Copolymer And Their Size Influence On The Properties Of Concrete, Cole R. Davis, Kendra A. Erk, Stacey L. Kelly

The Summer Undergraduate Research Fellowship (SURF) Symposium

Shrinkage leading to cracking and mechanical instability is a major problem for concrete due to the loss of water during the curing process. However, through the addition of Superabsorbent Polymer (SAP) hydrogels, shrinkage can be prevented, increasing the strength of concrete. Characterization of suspension polymerized polyacrylamide (PAM) poly(sodium acrylate-polyacrylamide) (PANa-PAM) copolymer microsphere sizes, morphology and swelling behavior was conducted before adding them to concrete. Size was determined using microscopy paired with ImageJ analysis. Coulter Counter size characterization was also used to determine the particle size distribution. Swelling behavior was determined using the tea bag method as well as size analysis …

Multi-Axial Failure Of High-Performance Fiber During Transverse Impact, Matthew C. Hudspeth

Open Access Dissertations

The effect of projectile nose geometry on ensuing wave development in high-performance yarns is explored during single yarn transverse impact. Special attention has been placed on visualizing the immediate region around the projectile-yarn contact site for 0.30-cal round, 0.30-cal fragment simulation projectiles (FSP), and razor blades using high-speed imaging. Kevlar® KM2, Dyneema®SK76 and AuTx have been impacted at velocities ranging from ∼100 m/s to ∼1200 m/s depending on projectile nose shape, with an emphasis set on determining the critical velocity wherein below said velocity significant development of wave propagation occurs and above said velocity the yarn fails immediately upon impact. …

Analytical Investigation Of Fretting Wear With Special Emphasis On Stress Based Models, Arnab Jyoti Ghosh

Open Access Dissertations

Fretting refers to the minute oscillatory motion between two surfaces in contact under an applied normal load. It can cause either surface or subsurface initiated failure resulting in either fatigue or wear or both. Two distinct regimes – partial slip and gross slip are typically observed in fretting contacts. Due to the nature of contact, various factors such as wear debris, oxidation, surface roughness, humidity etc. effect failures caused due to fretting. A number of different techniques have been developed to quantify fretting damage and several numerical models are proposed to predict damage due to fretting. Fretting wear also depends …

Detailed Finite Element Analysis And Preliminary Study Of The Effects Of Friction And Fastener Pre-Tension On The Mechanical Behavior Of Fastened Built-Up Members, Francisco Javier Bonachera Martin

Open Access Theses

The characterization of fatigue resistance is one of the main concerns in structural engineering, a concern that is particularly important in the evaluation of existing bridge members designed or erected before the development of fatigue design provisions. The ability of a structural member to develop alternate load paths after the failure of a component is known as member-level or internal redundancy. In fastened built-up members, these alternate load paths are affected by the combination of fastener pre-tension and friction between the structural member components in contact. In this study, a finite element methodology to model and analyze riveted and bolted …

Designing Meaningful Molecular Dynamics (Md) Simulations: The Lithiation Of Silicon, María Camila Rincon, Alejandro Strachan, Hojin Kim, David Guzman, Mathew Cherukara

The Summer Undergraduate Research Fellowship (SURF) Symposium

Molecular dynamics (MD) is used to understand the properties of materials by following the time evolution of the system and exploring the interactions between its constituent atoms. MD simulation allows making reliable predictions of various properties of materials; however, designing useful computer experiments is a complex task that requires the appropriate selection of interatomic interactions (force fields) and other conditions. In this work we discuss some aspects of molecular dynamics that would help the inexperienced users design reliable simulations. The simulation of the lithiation process of silicon is taken as an example for better understanding.

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

Code Optimization For Phase Field Method, Sergio Andres Monsalve, Marisol Koslowski

The Summer Undergraduate Research Fellowship (SURF) Symposium

The Phase field model method for studying grain dislocation at atomic level after applying an external force to the materials being tested, enables simulate the behavior of different materials after applying stress. With the appropriate numerical method the simulation could change drastically the complexity of the algorithm. Finding the most accurate and stable numerical method for the phase field model give us a considerable improving in the performance of the code used to simulate the phase field dynamic dislocation in larger and more complex simulations can be performed. We made an statistic comparison between the different methods, comparing stability and …

Preparation Of Mesoporous Silica Supported Ruthenium Oxides And The Application And Kinetic Study In The Catalysis Of Water Oxidation, Yang Zhang

Open Access Dissertations

Photo-induced water splitting of water into H2 and O2 has been a major focus in the development of clean and renewable energy. The development of viable and efficient catalysts that facilitates O2 production remains the major challenge in the study of the corresponding half-reaction of water oxidation. There are plenty of metal oxides reported active in the catalysis of water oxidation. However, several important performance bench marks of those materials, such as the non-stoichiometric production of O2, slow reaction rate and/or low quantum efficiency, remain to be improved.

Ruthenium oxide (RuO2) has long been known as one of the most …

Fabricating Complex-Shaped Components By Room-Temperature Injection Molding Of Aqueous Ceramic Suspension Gels, Valerie Lynn Wiesner

Open Access Dissertations

Water-based ceramic suspension gels (CeraSGels) effectively produced dense, near-net shape ceramic parts by room-temperature injection molding, a novel processing method based on traditional ceramic injection molding. This alternative method eliminated the need for heating and cooling feedstocks to process, as is required in conventional injection molding, through control of the rheological response of the CeraSGels by simply varying polymer content without the use of any harsh crosslinking or curing agents or further chemical processes. The development of room-temperature injection molding initially focused on forming CeraSGels based on alumina, a readily available model material, in order to optimize suspension preparation and …

Design And Assembly Of Nanostructured Complex Metal Oxide Materials For The Construction Of Batteries And Thermoelectric Devices, Gautam Ganapati Yadav

Open Access Dissertations

Thermoelectric devices and lithium-ion batteries are among the fastest growing energy technologies. Thermoelectric devices generate energy from waste heat, whereas lithium-ion batteries store energy for use in commercial applications. Two different topics are bound with a common thread in this thesis - nanotechnology! In fact, nanostructuring is a more preferred term for the approach I have taken herein. Another commonality between these two topics is the material system I have used to prove my hypotheses - complex metal oxides.

Complex metal oxides can be used for both energy generation and storage as they are stable at high temperatures, are benign …

The Effects Of A Collaborative Problem-Based Learning Experience On Students’ Motivation In Engineering Capstone Courses, Brett D. Jones, Cory M. Epler, Parastou Mokri, Lauren H. Bryant, Marie C. Paretti

Interdisciplinary Journal of Problem-Based Learning

We identified and examined how the instructional elements of problem-based learning capstone engineering courses affected students’ motivation to engage in the courses. We employed a two-phase, sequential, explanatory, mixed methods research design. For the quantitative phase, 47 undergraduate students at a large public university completed a questionnaire that measured the components of the MUSIC Model of Academic Motivation (Jones, 2009): empowerment, usefulness, success, situational interest, individual interest, academic caring, and personal caring. For the qualitative phase that followed, 10 students answered questions related to the MUSIC components. We identified several instructional elements that led to motivating opportunities that affected students’ …

Energy, U.S. Department Of, Bert Chapman

Libraries Faculty and Staff Scholarship and Research

Provides information about the U.S. Department of Energy (DOE) and its predecessor agencies and how DOE influences federal energy policy and scientific research in the western U.S.

Analysis Of An Actuated Two Segment Leg Model Of Locomotion, Nikhil Vinayak Rao

Open Access Theses

Research studies on dynamic models of legged locomotion have generally focused on telescoping-type leg models. Such telescoping spring loaded inverted pendulum (SLIP) models have been able to accurately predict observed center of mass (CoM) trajectories. There have been comparatively fewer studies on dynamics of locomotion

with segmented legs. Some earlier studies on the dynamics due to leg segmentation appear straightforward. For example, a simple model with the only joint moment being due to a passive springy knee has been shown to behave similarly to a telescoping spring-mass model. However, in real-life animal locomotion, there are multiple joint-moments acting at the …

Orientation Controllable Epitaxial Vapor-Liquid-Solid Semiconductor Nanowire Synthesis On Silicon Substrate, Sung Hwan Chung

Open Access Dissertations

Semiconductor nanowires synthesized via the vapor-liquid-solid (VLS) mechanism have attracted extensive research interest in recent years owing to their unique structure as a promising candidate for the future electronic devices. Germanium and silicon nanowires, in particular, are compatible with the current silicon-based technology via direct assembly. However, one of the main challenges for the successful nanowire application in large-scale is the lack of the method for obtaining nanowires in desired positions and directions. Therefore, the comprehensive, systematic understanding of epitaxial nanowire growth and the more suitable method to align nanowires on novel structure are required. In this work, the synthesis …

Acoustic Emission Detection Of Metals And Alloys During Machining Operations, Jameson K. Nelson

Purdue Polytechnic Masters Theses

Nelson, Jameson K. M.S., Purdue University, May 2012. Acoustic Emission Detection of Metals and Alloys During Machining Operations. Major Professor: Rodney G. Handy.

Practical correlation between material deformation attributes and theoretical concepts of machining has proven difficult to attain. The purpose of this study was to further explore trends and relationships using acoustic emission detection of materials undergoing single-point lathe turning machine processes. The majority of machining experiments that incorporate acoustic emissions focuses on tool degradation for the purposes of optimizing consumables required to manufacture mechanical devices. Experiments were implemented varying recording location, mechanical barrier condition, and machine parameters. The …

A Digital Hydraulic Valve, Actuated Using A Piezoelectric Linear Motor, Brian C. Bevill

Purdue Polytechnic Directed Projects

Proportional control in hydraulics is widely utilized. The most widely used current types of proportional valves utilize solenoid technology. While this technology has been around for decades and has been proven an effective means of control, there is always a demand for improved performance of advancing technologies. Integrating piezoelectric devices as a means to control hydraulic systems helps advance control for hydraulic systems.

Piezoelectric stack devices have been used to control hydraulic systems with success. Advantages of these stacks include being relatively small with a high power to weight ratio, using less energy than solenoid operations, and being fast acting. …

Identification Of Multiple Oscillation States Of Carbon Nanotube Tipped Cantilevers Interacting With Surfaces In Dynamic Atomic Force Microscopy, Mark Strus, Arvind Raman

Birck and NCN Publications

Carbon nanotubes (CNTs) have gained increased interest in dynamic atomic force microscopy (dAFM) as sharp, flexible, conducting, nonreactive tips for high-resolution imaging, oxidation lithography, and electrostatic force microscopy. By means of theory and experiments we lay out a map of several distinct tapping mode AFM oscillation states for CNT tipped AFM cantilevers: namely, noncontact attractive regime oscillation, intermittent contact with CNT slipping or pinning, or permanent contact with the CNT in point or line contact with the surface while the cantilever oscillates with large amplitude. Each state represents fundamentally different origins of CNT-surface interactions, CNT tip-substrate dissipation, and phase contrast …