Developing Strategies To Toughen Bio-Inspired Adhesives, 2018 Indiana University of Pennsylvania
Developing Strategies To Toughen Bio-Inspired Adhesives, Narelli P. Narciso, Samuel Lee Huntington, Jonathan J. Wilker
The Summer Undergraduate Research Fellowship (SURF) Symposium
Mussels and other marine creatures adhere very well in underwater environments, having the ability to withstand the force of the sea. These animals have inspired synthetic biomimetic adhesives for wet systems, presenting potential for biomedical applications. However, most current commercial adhesives tend to be brittle, not resisting repetitive movements. This study assesses toughening strategies to improve the mussel-inspired adhesives’ ductility while maintaining its strength. The strategies included altering the polymer’s chemical structure by changing the percentage of polyethylene glycol (PEG) in the molecule and by adding fillers, such as calcium carbonate, silica and nacre - a calcium carbonate compound found ...
Full Field Computing For Elastic Pulse Dispersion In Inhomogeneous Bars, 2018 Tallinn University of Technology
Full Field Computing For Elastic Pulse Dispersion In Inhomogeneous Bars, A. Berezovski, R. Kolman, M. Berezovski, D. Gabriel, V. Adamek
In the paper, the finite element method and the finite volume method are used in parallel for the simulation of a pulse propagation in periodically layered composites beyond the validity of homogenization methods. The direct numerical integration of a pulse propagation demonstrates dispersion effects and dynamic stress redistribution in physical space on example of a one-dimensional layered bar. Results of numerical simulations are compared with analytical solution constructed specifically for the considered problem. Analytical solution as well as numerical computations show the strong influence of the composition of constituents on the dispersion of a pulse in a heterogeneous bar and ...
Tunable Plasmonic Resonances In Highly Porous Nano-Bamboo Si-Au Superlattice-Type Thin Films, 2018 University of Nebraska - Lincoln
Tunable Plasmonic Resonances In Highly Porous Nano-Bamboo Si-Au Superlattice-Type Thin Films, Ufuk Kılıç, Alyssa Mock, René Feder, Derek Sekora, Matthew J. Hilfiker, Rafal Korlacki, Eva Schubert, Christos Argyropoulos, Mathias Schubert
Faculty Publications from the Department of Electrical and Computer Engineering
We report on fabrication of spatially-coherent columnar plasmonic nanostructure superlattice-type thin films with high porosity and strong optical anisotropy using glancing angle deposition. Subsequent and repeated depositions of silicon and gold lead to nanometer-dimension subcolumns with controlled lengths. The superlattice-type columns resemble bamboo structures where smaller column sections of gold form junctions sandwiched between larger silicon column sections (“nano-bamboo”). We perform generalized spectroscopic ellipsometry measurements and finite element method computations to elucidate the strongly anisotropic optical properties of the highly-porous nano-bamboo structures. The occurrence of a strongly localized plasmonic mode with displacement pattern reminiscent of a dark quadrupole mode is ...
Artificial Neural Network And Finite Element Modeling Of Nanoindentation Tests On Silica, 2018 University of Nebraska - Lincoln
Artificial Neural Network And Finite Element Modeling Of Nanoindentation Tests On Silica, Kianoosh Koocheki
Civil Engineering Theses, Dissertations, and Student Research
Two major forms of Silica include the crystalline form named Quartz which consist of the sand grains in nature, and amorphous form named Silica Glass or Fused Silica which is commonly known as glass. Fused Silica is an amorphous crystal that can show plastic behavior at micro-scale despite its brittle behavior in large scales. Due to the amorphous and ductile nature of Fused Silica, this behavior may not be explained well using the traditional dislocation-based mechanism of plasticity for crystalline solids. The crystal plasticity happens due to shear stress and stored energy in the material as dislocations which does not ...
Smart Bandage For Monitoring And Treatment Of Chronic Wounds, 2018 Harvard Medical School
Smart Bandage For Monitoring And Treatment Of Chronic Wounds, Pooria Mostafalu, Ali Tamayol, Rahim Rahimi, Manuel Ochoa, Akbar Khalilpour, Gita Kiaee, Iman K. Yazdi, Sara Bagherifard, Mehmet R. Dokmeci, Babak Ziaie, Sameer R. Sonkusale, Ali Khademhosseini
Mechanical & Materials Engineering Faculty Publications
Chronic wounds are a major health concern and they affect the lives of more than 25 million people in the United States. They are susceptible to infection and are the leading cause of nontraumatic limb amputations worldwide. The wound environment is dynamic, but their healing rate can be enhanced by administration of therapies at the right time. This approach requires real-time monitoring of the wound environment with on-demand drug delivery in a closed-loop manner. In this paper, a smart and automated flexible wound dressing with temperature and pH sensors integrated onto flexible bandages that monitor wound status in real-time to ...
Continuous Flow Process For Recovery Of Metal Contaminants From Industrial Wastewaters With Magnetic Nanocomposites, David Hutchins
Graduate Theses & Non-Theses
Remediation of metal-containing industrial effluents presents both a technical challenge and an economic opportunity. Many industrial waste streams contain low levels of metal ions requiring treatment prior to discharge. Existing treatment technologies are frustrated by disparate compositions and low metal concentrations. Chemical precipitation is effective; however, it requires excessive reagents and discourages selective recovery. Ion-exchange enables recovery, but requires a batch process with extensive operational and maintenance demands, and is rarely implemented in large-scale applications. A continuous flow process capable of selective recovery would present many advantages over existing technologies.
This research examines and develops a continuous flow process for ...
Energy Conversion System For Travelers (Ecost), 2018 Chulalongkorn University Demonstration Secondary School
Energy Conversion System For Travelers (Ecost), Thipok Bovornratanaraks
The International Student Science Fair 2018
We have innovated “The Energy Conversion System for Travelers” or the ECoST. With the fact that most travelers have wheeled cabin-bags, whilst walking, the wheels will rotate so why don’t we harvest electricity from this kinetic energy? We thus install our innovation, the ECoST, to the bag to generate electricity from the spinning wheels. The electricity is then kept in the storage unit and ready to charge your empty battery devices in an emergency case via a USB port. To make life easy, our ECoST was designed to replicate the power bank charging method; therefore, we can charge it ...
A Coupled Thermo-Mechanical Theory Of Strain Gradient Plasticity For Small And Finite Deformations, 2018 Louisiana State University and Agricultural and Mechanical College
A Coupled Thermo-Mechanical Theory Of Strain Gradient Plasticity For Small And Finite Deformations, Yooseob Song
LSU Doctoral Dissertations
In this work, a thermodynamically consistent coupled thermo-mechanical gradient enhanced continuum plasticity theory is developed for small and finite deformations. The proposed model is conceptually based on the dislocations interaction mechanisms and thermal activation energy. The thermodynamic conjugate microstresses are decomposed into energetic and dissipative components. This work incorporates the thermal and mechanical responses of microsystems. It addresses phenomena such as size and boundary effects and in particular microscale heat transfer in fast-transient processes. Not only the partial heat dissipation caused by the fast transient time, but also the distribution of temperature caused by the transition from the plastic work ...
Effect Of Material Viscoelasticity On Frequency Tuning Of Dielectric Elastomer Membrane Resonators, 2018 The University of Western Ontario
Effect Of Material Viscoelasticity On Frequency Tuning Of Dielectric Elastomer Membrane Resonators, Liyang Tian
Electronic Thesis and Dissertation Repository
Dielectric elastomers (DEs) capable of large voltage-induced deformation show promise for applications such as resonators and oscillators. However, the dynamic performance of such vibrational devices is not only strongly affected by the nonlinear electromechanical coupling and material hyperelasticity, but also significantly by the material viscoelasticity. The material viscoelasticity of DEs originates from the highly mobile polymer chains that constitute the polymer networks of the DE. Moreover, due to the multiple viscous polymer subnetworks, DEs possess multiple relaxation processes. Therefore, in order to predict the dynamic performance of DE-based devices, a theoretical model that accounts for the multiple relaxation processes is ...
High Performance Thermal Insulation: Silica Aerogels In Construction Technology, 2018 Union College
High Performance Thermal Insulation: Silica Aerogels In Construction Technology, Matthew Giarrusso
The United States is a world leader in the production and expenditure of energy, accounting for 18% of the total global energy consumption in 2016, 40% of which was used for the heating, cooling, and lighting of commercial and residential buildings. Currently, traditional air-based insulation products are being used in thicker and more numerous layers in an attempt to keep up with contemporary codes and standards. One promising alternative to traditional insulation is silica aerogel. With a remarkably low density and thermal conductivity, silica aerogel could save energy, space, and weight in new and retrofit structures. Silica aerogels are currently ...
Direct Synthesis Of Graphene On Niobium And Niobium Nitride, 2018 Portland State University
Direct Synthesis Of Graphene On Niobium And Niobium Nitride, Robin Ekeya, Otto Zietz
Undergraduate Research & Mentoring Program
Since its isolation by mechanical exfoliation in 2004, graphene has attracted enormous interest from the scientific community not the least because of its unique physical and electronic properties. Among these, graphene’s ballistic electron transport and proximity induced superconductivity make graphene-superconductor (GS) hybrid structures a scientifically promising area.
Microwave Acoustic Saw Resonators For Stable High-Temperature Harsh-Environment Static And Dynamic Strain Sensing Applications, Anin K. Maskay
Electronic Theses and Dissertations
High-temperature, harsh-environment static and dynamic strain sensors are needed for industrial process monitoring and control, fault detection, structural health monitoring in power plant environments, steel and refractory material manufacturing, aerospace, and defense applications. Sensor operation in the aforementioned extreme environments require robust devices capable of sustaining the targeted high temperatures, while maintaining a stable sensor response. Current technologies face challenges regarding device or system size, complexity, operational temperature, or stability.
Surface acoustic wave (SAW) sensor technology using high temperature capable piezoelectric substrates and thin film technology has favorable properties such as robustness; miniature size; capability of mass production; reduced installation ...
Archaeology And Conservation Of The Middle Phrygian Gate Complex At Gordion, Turkey, 2018 Boğaziçi Üniversitesi
Archaeology And Conservation Of The Middle Phrygian Gate Complex At Gordion, Turkey, Semih Gönen, Richard F. Liebhart, Naomi F. Miller, Elspeth Dusinberre
Classics Faculty Contributions
In 2016, a project was undertaken at Gordion, Turkey, to stabilize and conserve the remains of a rubble platform built early in the Middle Phrygian period (ca. 800–700 b.c.e.) under the vast Gate Complex leading to the megarons on the Citadel Mound. In the process, aspects of Middle Phrygian building strategies came to light that enhanced our understanding gained from the original excavation in the 1950s. This article outlines the archaeology of the Middle Phrygian Gate Complex and the sophisticated internal structures that lent stability to the rubble platform upon which it was built, and examines the ...
The Drag Coefficient Of Varying Dimple Patterns, 2018 Linfield College
The Drag Coefficient Of Varying Dimple Patterns, James M. Seeley, Michael S. Crosser
There are many golf balls on the market today with varying dimple sizes, shapes, and distribution. These proprietary differences are all designed to reduce drag on the balls during flight, allowing golfers to hit the ball farther distances. There are limited published studies comparing how varying the dimples affects the reduction of drag. An experiment was developed in which golf balls were pulled through a water tank to measure the drag force acting on each ball. The water was chosen to allow for testing at slower velocities than the typical necessary speeds to cause turbulence for balls traveling in air ...
Critical-Point Model Dielectric Function Analysis Of Wo3 Thin Films Deposited By Atomic Layer Deposition Techniques, 2018 University of Nebraska - Lincoln
Critical-Point Model Dielectric Function Analysis Of Wo3 Thin Films Deposited By Atomic Layer Deposition Techniques, Ufuk Kılıç, Derek Sekora, Alyssa Mock, Rafał Korlacki, Elena M. Echeverría, Natale J. Ianno, Eva Schubert, Mathias Schubert
Faculty Publications from the Department of Electrical and Computer Engineering
WO3 thin films were grown by atomic layer deposition and spectroscopic ellipsometry data gathered in the photon energy range of 0.72-8.5 eV and from multiple samples was utilized to determine the frequency dependent complex-valued isotropic dielectric function for WO3. We employ a critical-point model dielectric function analysis and determine a parameterized set of oscillators and compare the observed critical-point contributions with the vertical transition energy distribution found within the band structure of WO3 calculated by density functional theory. We investigate surface roughness with atomic force microscopy and compare to ellipsometric determined effective roughness layer thickness.
Lithium And The Foreseeable Future, 2018 University of Arkansas, Fayetteville
Lithium And The Foreseeable Future, Paolo Vargas
Mechanical Engineering Undergraduate Honors Theses
This paper aims to clarify the uncertainties regarding worldwide lithium resource availability in the years to come. Previous studies made on the subject are presented with some ambiguity and this work intends to fill the gaps. The information and data presented throughout this script with respect to global lithium resources and reserves are mostly based on data released by the United States Geological Survey (USGS). Lithium resource availability in the future is a point of paramount significance primarily for the automotive, portable electronics, and the power generation industry. Since, a change of supply would ultimately affect the price of lithium ...
Mechanical Characterization And Shear Test Comparison For Continuous-Fiber Polymer Composites, 2018 The University of Western Ontario
Mechanical Characterization And Shear Test Comparison For Continuous-Fiber Polymer Composites, Matthew Crossan
Electronic Thesis and Dissertation Repository
As fiber-reinforced composites continue to be used in a wide-range of high performance structures, more detailed understanding and accurate prediction of stress-strain behaviour is necessary to improving designs and reducing costs. This thesis compares the experimental behaviour of a continuous fiber polymer composite of carbon fiber and epoxy resin using Digital Image Correlation to analytical and theoretical predictions. Furthermore, an in-depth analysis of shear testing methods reveals the advantages and limitations of different testing standards. Finally, the limitations of the Iosipescu Shear test (ASTM 5379) fixture to break high-strain-to-failure composites in comparison to the V-notched Rail Shear Fixture (ASTM 7078 ...
Solar Radiation Parameters For Assessing Temperature Distributions On Bridge Cross-Sections, 2018 Fuzhou University
Solar Radiation Parameters For Assessing Temperature Distributions On Bridge Cross-Sections, Junqing Xue, Jianhui Lin, Bruno Briseghella, Habib Tabatabai, Baochun Chen
Civil and Environmental Engineering Faculty Articles
Solar radiation is one of the most important factors influencing the temperature distribution on bridge girder cross-sections. The bridge temperature distribution can be estimated using estimation models that incorporate solar radiation data; however, such data could be cost- or time-prohibitive to obtain. A review of literature was carried out on estimation models for solar radiation parameters, including the global solar radiation, beam solar radiation and diffuse solar radiation. Solar radiation data from eight cities in Fujian Province in southeastern China were obtained on site. Solar radiation models applicable to Fujian, China were proposed and verified using the measured data. The ...
Review Of Challenges And Advances In Modification Of Food Package Headspace Gases, 2018 University of Florida
Review Of Challenges And Advances In Modification Of Food Package Headspace Gases, Ziynet Boz, Bruce A. Welt, Jeffrey K. Brecht, William Pelletier, Eric Mclamore, Gregory A. Kiker, Jason E. Butler
Journal of Applied Packaging Research
Modified Atmosphere Packaging (MAP) has been widely used as an effective way to preserve foods. Fresh produce, meat and meat products, seafood, and dairy products can benefit from modified gaseous atmospheres, which are usually achieved by reducing oxygen and increasing carbon dioxide concentrations, within limits, defined by product tolerances. MAP of fresh produce is particularly challenging because products are living and respiring. Respiration rates depend on several factors including temperature, oxygen, and carbon dioxide concentrations. Balancing package permeation with respiration is challenging, often due to limited selection of practical packaging materials. Failing to remain within tolerance limits of products leads ...
An Evaluation Of Induction Heating In Healthcare Food Industry, 2018 Western Kentucky University
An Evaluation Of Induction Heating In Healthcare Food Industry, Barrett Alexander Hampton
Masters Theses & Specialist Projects
This thesis addresses the problem healthcare facilities are having in maintaining proper food temperatures while transporting meals to patients after food has left the kitchen area. Induction heat has been a known method for generating heat for many years. The commercial food industry currently uses this technology, which is beginning to appear in the residential sector as well because of developments made by manufacturers. This study focuses on the top commercial brand models of induction heaters and the supporting materials currently used to create heat sources to maintain food temperatures in hospitals and long term care facilities.
The research in ...