Engineering Commons^™

Tribo-Corrosion Response Of Additively Manufactured High-Entropy Alloy, Jibril Shittu, Maryam Sadeghilaridjani, Mayur Pole, Saideep Muskeri, Jie Ren, Yanfang Liu, Ismael Tahoun, Harpreet Arora, Wen Chen, Narendra Dahotre

Mechanical and Industrial Engineering Faculty Publication Series

High-entropy alloys (HEAs) with multiple principal elements represent a paradigm shift in structural alloy design and show excellent surface degradation resistance in corrosive environment. Here, the tribo-corrosion response of laser-engineered net-shaped CoCrFeMnNi HEA was evaluated in 3.5 wt% NaCl solution at room temperature. The additively manufactured (AM-ed) CoCrFeMnNi showed five times lower wear rate, regenerative passivation, and nobler corrosion potential during tribo-corrosion test compared to its arc-melted counterpart. A significant anisotropy was seen in the tribo-corrosion response with 45 degrees to the build direction showing better performance compared to tests along the build direction and perpendicular to it. The open …

Strain Effects On The Diffusion Properties Of Near-Surface Self-Interstitial Atoms And Adatoms In Tungsten, Bochuan Sun, Dimitrios Maroudas, Brian D. Wirth, Enrique Martínez

Chemical Engineering Faculty Publication Series

Tungsten (W) is a candidate for the plasma-facing components and divertor in future fusion applications. The material will be subject to a large particle influx (mainly helium and hydrogenic species) that will form bubbles. As bubbles grow, they compress the material, adding to thermal stresses, and eject self-interstitial atoms (SIAs-isolated or in clusters) to release internal pressure. These SIAs diffuse towards the surface in large stress/strain fields and on the surface are thought to act as precursors for nanotendril formation (also known as fuzz) that develops on the material surface modifying its morphology. In this work we analyze the effect …

Patterns Around Us Presentation, Benny Davidovitch

Patterns Around Us

No abstract provided.

Functional Droplets That Recognize, Collect, And Transport Debris On Surfaces, Ying Bai, Chia-Chih Chang, Umesh Choudhary, Irem Bolukbasi, Alfred J. Crosby, Todd Emrick

Polymer Science and Engineering Department Faculty Publication Series

We describe polymer-stabilized droplets capable of recognizing and picking up nanoparticles from substrates in experiments designed for transporting hydroxyapatite nanoparticles that represent the principal elemental composition of bone. Our experiments, which are inspired by cells that carry out materials transport in vivo, used oil-in-water droplets that traverse a nanoparticle-coated substrate driven by an imposed fluid flow. Nanoparticle capture is realized by interaction of the particles with chemical functionality embedded within the polymeric stabilizing layer on the droplets. Nanoparticle uptake efficiency is controlled by solution conditions and the extent of functionality available for contact with the nanoparticles. Moreover, in an elementary …

A Comparison Of The Elastic Properties Of Graphene- And Fullerene-Reinforced Polymer Composites: The Role Of Filler Morphology And Size, Chang-Tsan Lu, Asanka Weerasinghe, Dimitrios Maroudas, Ashwin Ramasubramaniam

Mechanical and Industrial Engineering Faculty Publication Series

Nanoscale carbon-based fillers are known to significantly alter the mechanical and electrical properties of polymers even at relatively low loadings. We report results from extensive molecular-dynamics simulations of mechanical testing of model polymer (high-density polyethylene) nanocomposites reinforced by nanocarbon fillers consisting of graphene flakes and fullerenes. By systematically varying filler concentration, morphology, and size, we identify clear trends in composite stiffness with reinforcement. To within statistical error, spherical fullerenes provide a nearly size-independent level of reinforcement. In contrast, two-dimensional graphene flakes induce a strongly size-dependent response: we find that flakes with radii in the 2–4 nm range provide appreciable enhancement …

Syllabus: Solar Energy Systems And Building Design, Ho-Sung Kim

Sustainability Education Resources

This course introduces the fundamental concepts of solar building design and energy systems. Through project based study and possible field visits, students will explore the theory, technologies, applications, and benefits of solar design of buildings and discover how to utilize solar energy systems for residential and commercial buildings. Students will be required to research and document technology and complete a semester case study project in which they will examine various energy conservation aspects and economics underlying solar energy systems.

Material Characterization And Computational Simulation Of Steel Foam For Use In Structural Applications, Brooks H. Smith

Masters Theses 1911 - February 2014

Cellular metals made from aluminum, titanium, or other metals are becoming increasingly popular for use in structural components of automobiles, aircraft, and orthopaedic implants. Civil engineering applications remain largely absent, primarily due to poor understanding of the material and its structural properties. However, the material features a high stiffness to weight ratio, excellent energy dissipation, and low thermal conductivity, suggesting that it could become a highly valuable new material in structural engineering. Previous attempts to characterize the mechanical properties of steel foam have focused almost exclusively upon uniaxial compression tests, both in experimental research and in computational simulations. Further, computational …

Torsional Shear Strength And Size Effect In Structural Composite Lumber, Zhuo Yang

Masters Theses 1911 - February 2014

The natural variation of strength properties within brittle materials leads to size effect, a well-known phenomenon whereby the mean strength of a material is observed to decrease as the stressed volume increases. An important implication of size effect is that size adjustment parameters must be incorporated into multi-axial constitutive and failure models used in numerical simulations to predict material response to loading. This experimental study seeks to verify and quantify the presence of depth effect under shear failure in the orthotropic principal material directions of parallel strand lumber (PSL) and laminated veneer lumber (LVL). Torsion tests have been performed on …

Patterned Well-Ordered Mesoporous Silica Films For Device Fabrication, Todd A. Crosby

Masters Theses 1911 - February 2014

Developing effective methods of generating thin metal oxide films are important for sensing and separations applications. An obstacle to device fabrication is controlling the size and spatial orientation of domain level pores while retaining the ability to generate arbitrary device level patterns. Well-ordered hexagonally packed cylindrical pores were created by taking advantage of block copolymer self-assembly followed by selective condensation of silica precursors using supercritical carbon dioxide as the solvent. It was possible to control the pore size by choosing PEO-PPO-PEO (Pluronic® series) triblock copolymers of differing molecular weights.

These processes were then incorporated with conventional lithographic techniques to generate …

Miami Furniture Study, Center For Economic Development

Center for Economic Development Technical Reports

This research project, under the guidance of Dr. John Mullin and Professor Zenia Kotval, sought to study and examine Miami's fledgling furniture cluster as well as key elements of the American furniture industry. I believe that this report presents an honest unbiased "snapshot" of the American furniture industry and the City of Miami's furniture design district. All of the information contained within this report has been cited and referenced to the best of my ability.