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Application Of Computational Tools To Spaghetti-Based Truss Bridge Design, Jin Xu, Jiliang Li, Nuri Zeytinoglu, Jinyuan Zhai 2019 Purdue University Northwest

Application Of Computational Tools To Spaghetti-Based Truss Bridge Design, Jin Xu, Jiliang Li, Nuri Zeytinoglu, Jinyuan Zhai

ASEE IL-IN Section Conference

Application of Computational Tools to Spaghetti-Based Truss Design

Statics and Strength of Materials are two foundational courses for Mechanical/Civil Engineering. In order to assist students in better understanding and applying concepts to a meaningful design task, SolidWorks and theoretical calculation were used for a spaghetti-bridge design contest with the constraints of given maximum weight and allowable support-material weight. As the first step of this iterative designing process, both extrude feature and structural member were introduced to model planar bridge trusses. Then SolidWorks’ Statics module was used to run FEA analysis of the structural performance in efforts to optimize the ...


Soft , Multilayered Electronics For Wearable Devices And Methods To Produce The Same, Carmel Majidi, Michael D. Bartlett, Eric J. Markvicka 2019 University of Nebraska - Lincoln

Soft , Multilayered Electronics For Wearable Devices And Methods To Produce The Same, Carmel Majidi, Michael D. Bartlett, Eric J. Markvicka

Mechanical & Materials Engineering Faculty Publications

Disclosed herein is an efficient fabrication approach to create highly customizable wearable electronics through rapid laser machining and adhesion - controlled soft materials assembly . Well - aligned , multi - layered materials can be created from 2D and 3D elements that stretch and bend while seamlessly integrating with rigid components such as micro chip integrated circuits ( IC ) , discrete electrical components , and interconnects . These techniques are applied using commercially available materials . These materials and methods enable custom wearable electronics while offering versatility in design and functionality for a variety of bio - monitor ing applications .


Gastrointestinal Sensor Implantation System, Benjamin Terry, Weston Lewis, Wanchuan Xie, Pengbo Li, Alfred Tsubaki 2019 Lincoln , NE

Gastrointestinal Sensor Implantation System, Benjamin Terry, Weston Lewis, Wanchuan Xie, Pengbo Li, Alfred Tsubaki

Mechanical & Materials Engineering Faculty Publications

A gastrointestinal ( GI ) sensor deployment device is dis closed . In implementations , the sensor deployment device includes an orally - administrable capsule with a tissue cap ture device removably coupled to the orally - administrable capsule . The tissue capture device includes a plurality of fasteners for connecting the tissue capture device to GI tissue within a body . A biometric sensor is coupled to the tissue capture device for continuous or periodic monitoring of the GI tract of the body at the GI tissue attachment location . A chamber within the orally - administrable capsule is configured to draw gastrointestinal tissue towards the plurality of fasteners ...


Interactions Between Dislocations And Three-Dimensional Annealing Twins In Face Centered Cubic Metals, Yanxiang Liang, Xiaofang Yang, Mingyu Gong, Guisen Liu, Qing Liu, Jian Wang 2019 University of Nebraska–Lincoln

Interactions Between Dislocations And Three-Dimensional Annealing Twins In Face Centered Cubic Metals, Yanxiang Liang, Xiaofang Yang, Mingyu Gong, Guisen Liu, Qing Liu, Jian Wang

Mechanical & Materials Engineering Faculty Publications

Annealing twins often form in metals with a face centered cubic structure during thermal and mechanical processing. Here, we conducted molecular dynamic (MD) simulations for copper and aluminum to study the interaction processes between {1 1 1}1/2 <1 1 0> dislocations and a three-dimensional annealing twin. Twin boundaries are characterized with Σ3{1 1 1} coherent twin boundaries (CTBs) and Σ3{1 1 2} incoherent twin boundaries (ITBs). MD results revealed that dislocation-ITB interactions affect slip transmission for a dislocation crossing CTBs, facilitating the nucleation of Lomer dislocation.


Direct Observation Of Early Stages Of Growth Of Multilayered Dna-Templated Au-Pd-Au Core-Shell Nanoparticles In Liquid Phase, Nabraj Bhattarai, Tanya Prozorov 2019 Ames Laboratory

Direct Observation Of Early Stages Of Growth Of Multilayered Dna-Templated Au-Pd-Au Core-Shell Nanoparticles In Liquid Phase, Nabraj Bhattarai, Tanya Prozorov

Ames Laboratory Accepted Manuscripts

We report here on direct observation of early stages of formation of multilayered bimetallic Au-Pd core-shell nanocubes and Au-Pd-Au core-shell nanostars in liquid phase using low-dose in situ scanning transmission electron microscopy (S/TEM) with the continuous flow fluid cell. The reduction of Pd and formation of Au-Pd core-shell is achieved through the flow of the reducing agent. Initial rapid growth of Pd on Au along <111> direction is followed by a slower rearrangement of Pd shell. We propose the mechanism for the DNA-directed shape transformation of Au-Pd core-shell nanocubes to adopt a nanostar-like morphology in the presence of T30 DNA ...


Strength And Plasticity Of Amorphous Silicon Oxycarbide, Kaisheng Ming, Chao Gu, Qing Su, Yongqiang Wang, Arezoo Zare, Don A. Lucca, Michael Nastasi, Jian Wang 2019 University of Nebraska-Lincoln

Strength And Plasticity Of Amorphous Silicon Oxycarbide, Kaisheng Ming, Chao Gu, Qing Su, Yongqiang Wang, Arezoo Zare, Don A. Lucca, Michael Nastasi, Jian Wang

Mechanical & Materials Engineering Faculty Publications

Amorphous SiOC films were synthesized by magnetron sputtering at room temperature with/without radio frequency (RF) bias and further improved in terms of mechanical properties by ion irradiation. As-deposited SiOC films without RF bias exhibit catastrophic failure at a low stress and strain, which is ascribed to microstructural heterogeneities associated with the formation of voids during deposition, as evidenced by transmission electron microscopy. Ion irradiation unifies microstructure accompanied with eliminating the voids, resulting in a simultaneously increase in strength and plasticity (ultimate strength of 5–7 GPa and the strain to shear instability of over 20%). Homogeneous microstructures are demonstrated ...


Alternating Multiblock Polyethylenes With Associating Groups: Self-Assembled Nanoscale Morphologies And Ion Transport, Lu Yan 2019 University of Pennsylvania

Alternating Multiblock Polyethylenes With Associating Groups: Self-Assembled Nanoscale Morphologies And Ion Transport, Lu Yan

Publicly Accessible Penn Dissertations

Single-ion conductors based on block copolymers (BCPs) are promising solid-state electrolytes for energy storage systems. Their ability to self-assemble into distinct nanostructures can provide both high ion transference numbers and strong mechanical integrity. Connecting the microphase-separated morphologies to the ion transport properties in BCP electrolytes as well as designing polymers to produce specific ion-conducting domain remain a critically important challenge.

Combining non-conducting polyethylene (PE) blocks that alternate with short strongly-interacting ionic blocks leads to a wide range of intriguing nanoscale phase-separated morphologies. Depending on the PE block lengths, these alternating multiblock copolymers exhibit amorphous or semicrystalline morphologies and their ionic ...


Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng 2019 Iowa State University

Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng

Graduate Theses and Dissertations

Metal particles like aluminum and boron are of great interest as additives to energetic materials due to their high gravimetric and volumetric heat of combustion. However, the ignition temperatures of metals are quite high and their burning rates which depend upon the surface area of the burning metal agglomerates are quite slow. The naturally formed oxide layer on the surface of metal particles can further inhibit their ignition and combustion by limiting fuel/oxidizer transport. The boron oxide layer on boron particles is of particular interest due to the strong diffusion barrier formed by its presence. However, the ignition temperature ...


Calcium Passivation And Properties Of Al/Ca Composite Conductors, Charles Czahor 2019 Iowa State University

Calcium Passivation And Properties Of Al/Ca Composite Conductors, Charles Czahor

Graduate Theses and Dissertations

Light, strong, high-conductivity materials are desirable for overhead power transmission and distribution conductors. An aluminum/calcium composite with nanofilamentary reinforcement was produced by powder metallurgy and deformation processing to fine wires. Upon achieving the desired dimension, the wires were heat treated to convert the calcium to Al2Ca intermetallic reinforcement filaments. Extended heat treatments were used to evaluate the upper operating temperature of the material. The processing steps, microstructure, conductivity, and tensile strength of Al/Ca composites were evaluated. The measured properties indicate that the number of support towers required for a HVDC transmission line can be reduced by more than ...


Insights Into Performance Stability Of Lead-Free Piezoelectric Ceramics, Zhongming Fan 2019 Iowa State University

Insights Into Performance Stability Of Lead-Free Piezoelectric Ceramics, Zhongming Fan

Graduate Theses and Dissertations

Developing materials with superior functional properties is the primary goal of materials engineering. Nonetheless, the stability of performance during practical service should be of equal importance. This is, with no doubt, also true for piezoelectric materials.

The working conditions of piezoelectric materials can lead to either gradual or abrupt degradation in their functional properties. First, fatigue. In analogy to structural materials under cyclic stresses, the piezoelectric properties deteriorate during the electric field cycling. Second, aging. While the service is paused and the piezoelectric material is sitting idle, the piezoelectric properties will decay over time. Third, thermal depolarization. Electronic devices are ...


Solution Phase Synthesis Of Lead-Free Perovskite And Perovskite-Inspired Materials, Rainie Dean Nelson 2019 Iowa State University

Solution Phase Synthesis Of Lead-Free Perovskite And Perovskite-Inspired Materials, Rainie Dean Nelson

Graduate Theses and Dissertations

This dissertation is a broad overview of research in the field of lead-free perovskite

inspired materials. While lead halide perovskites have promising properties, we sought to

investigate non-toxic alternatives – typically ones containing bismuth halides. We looked

into the flexibility of this element to be produced on different length scales, fabricating films

from bulk material, synthesizing nanocrystals, and growing crystals of 2D layered double

perovskites. We discovered that due to complexation with a solvent, bismuth iodide films can

be morphology controlled through use of solvent additives. During our synthesis of Cs3Bi2X9

nanocrystals, we found that BiX3 precursors possessed photoluminescence and that ...


Designing Colloidal Nanomaterials For Electronic And Optoelectronic Devices Through Surface Modification, Tianshuo Zhao 2019 University of Pennsylvania

Designing Colloidal Nanomaterials For Electronic And Optoelectronic Devices Through Surface Modification, Tianshuo Zhao

Publicly Accessible Penn Dissertations

Colloidal quantum dots (QDs) are nanometer-sized semiconductors synthesized by wet chemical methods and stabilized by surface ligands in solvents. They are prized for the size-dependent electronic band structures, giving rise to tunable optical properties. Their solution form is also suitable for large-area and low-cost fabrication processes. These unique characteristics make this class of materials promising as building blocks for next-generation thin-film electronic and optoelectronic devices. However, the construction of QD based devices requires precise control of their material properties, including carrier mobility, lifetime, doping concentration and energy positions of the conduction and valence band edges. The large surface-to-volume ratio allows ...


Alignment And Morphological Effects Of Nanoplates In Lamellar Diblock Copolymer Thin Films, Nadia Krook 2019 University of Pennsylvania

Alignment And Morphological Effects Of Nanoplates In Lamellar Diblock Copolymer Thin Films, Nadia Krook

Publicly Accessible Penn Dissertations

The ability to disperse inorganic nanoparticles (NPs) of various shapes, sizes, and compositions in polymeric matrices enables researchers to continuously engineer new material combinations with different resulting properties. Polymer nanocomposites (PNCs) can be further customized for specific applications by intentionally organizing and orienting NPs within these hybrid materials. Despite significant advances in the field of PNCs, full control over the orientation of embedded anisotropic NPs, specifically nanoplates, is not well-established without employing multistep processes. Capturing either in-plane (parallel) or out-of-plane (vertical) orientation of nanoplates in thin polymer films through a scalable method would create new opportunities for developing coating technologies ...


Continuum Modeling Of Cell-Extracellular Environment Interaction, Xuan Cao 2019 University of Pennsylvania

Continuum Modeling Of Cell-Extracellular Environment Interaction, Xuan Cao

Publicly Accessible Penn Dissertations

To perform functions such as proliferation, differentiation, and locomotion, living cells establish stable attachments to the extracellular matrix (ECM) via the formation of specialized receptor mediated contact foci, through which they sense the mechanical stimuli from the ECM and adapt their cytoskeleton structures. The cellular contraction, on the other hand, may induce dramatic structural changes to the local extracellular environment, particularly for the fibrous matrices. The main goal of this thesis is to understand the cell-ECM interaction and cell-cell interaction, which lays the foundation to address the role of mechanical stimuli in several physiological and pathological processes such as cell ...


Investigation Of Ferroelectric Perovskite Oxides For Photovoltaic Applications, Liyan Wu 2019 University of Pennsylvania

Investigation Of Ferroelectric Perovskite Oxides For Photovoltaic Applications, Liyan Wu

Publicly Accessible Penn Dissertations

Ferroelectric materials have been demonstrated to be promising in developing emerging photovoltaic technologies because of the various mechanisms that allow above-bandgap photovoltages and higher efficiencies. However, the wide bandgaps of conventional ferroelectric oxides limit their utilization of the solar spectrum. This thesis focused on the identification of chemical substituents capable of reducing the bandgap of ferroelectric perovskite oxides, while retaining a robust polarization. Building upon the discovery of (1−x)KNbO3-xBa(Ni1/2Nb1/2)O2.75 solid solutions which have bandgaps compatible with traditional semiconductors, new families of Ni- and Ni/Nb-substituted BaTiO3 were fabricated through solid state methods. The ...


Diverse Colloidal Crystals And Clusters Formed By Dna-Grafted Spheres Via Self-Assembly, Yifan Wang 2019 University of Pennsylvania

Diverse Colloidal Crystals And Clusters Formed By Dna-Grafted Spheres Via Self-Assembly, Yifan Wang

Publicly Accessible Penn Dissertations

Meta-materials with novel photonic, phononic, thermal, and mechanical properties are considered as future materials for new applications. Colloidal crystals are meta-materials made from assemblies of building blocks that are not found in naturally occurring materials. Unlike atoms and molecules, such building blocks could be obtained from DNA-coated colloids which have feasible and adjustable interaction strengths as well as facilitating a further DNA-induced self-assembly into different geometries and structures. This DNA colloidal self-assembly prototyping process could be utilized as a fast and effective way for fabricating different structures, which shed light on the industrial production of the meta-materials.

In this work ...


Improving Performance Of Infiltrated Sofc Cathodes Via Scaffold Engineering And Catalyst Surface Engineering, Yuan Cheng 2019 University of Pennsylvania

Improving Performance Of Infiltrated Sofc Cathodes Via Scaffold Engineering And Catalyst Surface Engineering, Yuan Cheng

Publicly Accessible Penn Dissertations

Solid Oxide Fuel Cells (SOFCs) are energy-generating devices operating at elevated temperatures. At their cathode sides, oxygen molecules reduce into oxygen ions and then transport to the anode side through a solid-state ceramic membrane (typically, Yttria-Stabilized Zirconia (YSZ)). At their anode side, the fuels react with the oxygen ions and then release electrons to the external circuit. Always, it is the cathode that has the slowest reaction kinetics, such it contributes the largest resistance in the entire device.

The state-of-the-art cathode materials are typically perovskite-phase ceramic materials, such as Strontium-doped Lanthanum Manganate (LSM), Strontium-doped Lanthanum Ferrite (LSF) and Strontium-doped Lanthanum ...


A Computational And Experimental Study Of Polymer Conformation And Diffusion Under Confinement, James F. Pressly 2019 University of Pennsylvania

A Computational And Experimental Study Of Polymer Conformation And Diffusion Under Confinement, James F. Pressly

Publicly Accessible Penn Dissertations

Over the past several decades the use of polymers in applications such as microelectronics fabrication and nanocomposite materials has steadily increased. In these applications polymer chains are often confined to length scales comparable to their size. While it is well known that these confining environments alter polymer properties, a generalized understanding of how different confining geometries alter polymer behavior has not been established. Here we investigate changes to polymer conformation and diffusion under cylindrical and planar confinement using a combination of computational and experimental techniques. Using molecular dynamics simulations of polymer melts, we systematically examine changes in the polymer radius ...


Two-Dimensional Early Transition Metal Carbides As Supports For Platinum Catalysts, Zhe Li 2019 Iowa State University

Two-Dimensional Early Transition Metal Carbides As Supports For Platinum Catalysts, Zhe Li

Graduate Theses and Dissertations

Tuning catalytic active sites through metal-support interactions (MSIs) has emerged as an effective strategy to design supported metal catalysts. The development and selection of supports are paramount for achieving the desired catalytic performance, which are however, great challenges. This dissertation involves elucidating the MSIs between platinum and two-dimensional early transition metal carbides (MXenes) and harnessing the MSIs for several industrial catalytic processes and electrocatalytic reactions.

This work discovered the reactive metal support interactions (RMSI) in MXenes supported Pt catalysts. RMSI refers to a chemical reaction between a metal and the support that induces the formation of bimetallic structures. By utilizing ...


The Role Of Vec And Local Atomic Environment In Structural Transitions And Stability Of Complex Intermetallic Compounds Through Theoretical And Experimental Study Of Γ-Brasses, Stephanie L. Eveland 2019 Iowa State University

The Role Of Vec And Local Atomic Environment In Structural Transitions And Stability Of Complex Intermetallic Compounds Through Theoretical And Experimental Study Of Γ-Brasses, Stephanie L. Eveland

Graduate Theses and Dissertations

The fusion of computational and synthetic techniques provides a powerful investigative arsenal for a systematic consideration of the factors governing the structural makeup and observed physical properties of complex intermetallic compounds such as the non-uniform mixed sites in Mn2+xZn11-x, VEC driven structural transition in Mn5-yAl8-xZnx+y, and atypical atomic decoration of Cu9Al4 γ-brasses. Classic solid state synthetic techniques, self-flux techniques, as well as multiple structural characterization methods such as X-ray diffraction and electron microscopy were employed in the experimental portion of this work. Magnetic susceptibility measurements were utilized when appropriate in the study of the γ- brasses of Mn2 ...


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