Material Coefficient Of Thermal Expansion Investigation For Use In Additive Manufacturing Fused Deposition Modeling For Composite Tooling, 2015 The University of Southern Mississippi
Material Coefficient Of Thermal Expansion Investigation For Use In Additive Manufacturing Fused Deposition Modeling For Composite Tooling, Daniel Miller
Polymer matrix composites are being used to manufacture light weight, high stiffness aircraft structures. These structures are often manufactured from carbon fiber reinforced epoxy. When these structures are damaged, they must be repaired to restore strength to the component to avoid the cost and logistics of having replacements parts. Occasionally, these repairs require tooling in order to make a quality repair, however, tooling generally has a long lead time. Additive manufacturing could be used to manufacture rapid tooling to create tooling for composite repairs. The issue is that polymer printed tooling has a much higher coefficient of thermal expansion (CTE ...
Cure Kinetics, Morphologies, And Mechanical Properties Of Thermoplastic/Mwcnt Modified Multifunctional Glassy Epoxies Prepared Via Continuous Reaction Methods, 2015 University of Southern Mississippi
Cure Kinetics, Morphologies, And Mechanical Properties Of Thermoplastic/Mwcnt Modified Multifunctional Glassy Epoxies Prepared Via Continuous Reaction Methods, Xiaole Cheng
The primary goal of this dissertation is to develop a novel continuous reactor method to prepare partially cured epoxy prepolymers for aerospace prepreg applications with the aim of replacing traditional batch reactors. Compared to batch reactors, the continuous reactor is capable of solubilizing and dispersing a broad range of additives including thermoplastic tougheners, stabilizers, nanoparticles and curatives and advancing epoxy molecular weights and viscosities while reducing energy consumption.
In order to prove this concept, polyethersulfone (PES) modified 4, 4’-diaminodiphenylsulfone (44DDS)/tetraglycidyl-4, 4’-diaminodiphenylmethane (TGDDM) epoxy prepolymers were firstly prepared using both continuous reactor and batch reactor methods. Kinetic studies ...
Generalized Ellipsometry Analysis Of Anisotropic Nanoporous Media: Polymer-Infiltrated Nanocolumnar And Inverse-Column Polymeric Films, 2015 University of Nebraska–Lincoln
Generalized Ellipsometry Analysis Of Anisotropic Nanoporous Media: Polymer-Infiltrated Nanocolumnar And Inverse-Column Polymeric Films, Dan Liang
Electrical Engineering Theses and Dissertations
Characterization of the structural and optical properties is a subject of significance for nanoporous material research. However, it remains a challenge to find non-destructive methods for investigating the anisotropy of porous thin films with three-dimensional nanostructures. In this thesis, a generalized ellipsometry (GE) analysis approach is employed to study two types of anisotropic nanoporous media: slanted columnar thin films (SCTFs) with polymer infiltration and inverse-SCTF polymeric films. The thesis presents the physical properties obtained from GE analysis, including porosity, columnar shape, principal optical constants, birefringence, etc.
The thesis reports on using a GE analysis approach, combining the homogeneous biaxial layer ...
Crystal Nucleation Of Palladium-Doped Lithium Disilicate Glass, 2015 Southern Polytechnic State University
Crystal Nucleation Of Palladium-Doped Lithium Disilicate Glass, Gregory Humble
Symposium of Student Scholars
The effect of concentration of palladium particles on crystal nucleation was investigated for lithium disilicate glass. The heterogeneous nucleation rate for 470°C and 480°C were calculated for a concentration of 0.001% palladium by weight. The DTA method of measuring nucleation and crystallization was used in this calculation.
Towards Molecular Modification Of Carbon Nanotube Junctions In Thin Film Transistors, 2015 College of Arts and Sciences, Boise State University
Towards Molecular Modification Of Carbon Nanotube Junctions In Thin Film Transistors, Noelia Caloca, A. Nicole Chang, Kari Mclaughlin, David Estrada
College of Engineering Presentations
Carbon nanotube thin film transistors have recently been used on flexible and transparent substrates for applications in integrated circuits and display drivers. Such networks are of interest due to their relatively high carrier mobility and mechanical flexibility. However, the ION/IOFF ratio of these networks varies inversely with the carrier mobility, and advances in reducing the electrical and thermal resistance of nanotube junctions are needed to improve the device performance and reliability. The objective of this work is create a process to improve CNT TFT device performance by using 0-dimensional molecules to modify the physical properties of the ...
Towards The Perfect Optical Fiber, 2015 Clemson University
Towards The Perfect Optical Fiber, John Ballato
Journal of the South Carolina Academy of Science
Optical fibers are being used in an ever more diverse array of applications today. Many of these modern applications are in high-power and, particularly, high power-per-unit-bandwidth systems where optical nonlinearities historically have not limited overall performance. Today, however, nominally weak effects, such as stimulated Brillouin scattering (SBS), are restricting continued scaling to higher optical powers. To address these limitations, the optical fiber industry has focused on fiber geometry-related solutions such as large mode area (LMA) designs. However, since all linear and nonlinear optical phenomena are fundamentally materials-based in origin, this paper identifies material solutions to present and future performance limitations ...
Oxide Dispersion Strengthened Nickel Based Alloys Via Spark Plasma Sintering, 2015 University of Idaho
Oxide Dispersion Strengthened Nickel Based Alloys Via Spark Plasma Sintering, Somayeh Pasebani, Aniket K. Dutt, Jatuporn Burns, Indrajit Charit, Rajiv S. Mishra
Materials Science and Engineering Faculty Publications and Presentations
Oxide dispersion strengthened (ODS) nickel based alloys were developed via mechanical milling and spark plasma sintering (SPS) of Ni–20Cr powder with additional dispersion of 1.2 wt% Y2O3 powder. Furthermore, 5 wt% Al2O3 was added to Ni–20Cr–1.2Y2O3 to provide composite strengthening in the ODS alloy. The effects of milling times, sintering temperature, and sintering dwell time were investigated on both mechanical properties and microstructural evolution. A high number of annealing twins was observed in the sintered microstructure for all the milling times. However, longer milling time contributed ...
Characterization Of High-Pressure-Die-Cast Magnesium Alloy Am60, 2015 The University of Western Ontario
Characterization Of High-Pressure-Die-Cast Magnesium Alloy Am60, Hooman Baghaei Anaraki
University of Western Ontario - Electronic Thesis and Dissertation Repository
The primary goal of this study is the characterization of high pressure die cast magnesium alloys AM60 so that the failure model which is proposed by J.Weiler can be validated for two new castings. The input variables of failure model can be determined by characterization of different regions within the castings. Based on the location of gate system, the desired regions are identified across both castings and tensile specimens are extracted from various regions. Therefore the local mechanical properties are determined, and fracture strain of samples ranges from 1.2 to 9.5%. The area fraction of porosities and ...
Söyleşi- Rauf H Eric, Güney Afrika'da Madencilik Ve Metal Kazanımı (Interview With Rauf H Eric, Mining And Metal Extraction In South Africa), Ahmet Deniz Bas
Ahmet Deniz Bas
No abstract provided.
Methods For Analyzing The Structure Of Creases In Heat Sealed Paperboard Packages, 2015 Lappeenranta University of Technology
Methods For Analyzing The Structure Of Creases In Heat Sealed Paperboard Packages, Ville Leminen, Petri Mäkelä, Panu Tanninen, Juha Varis
Journal of Applied Packaging Research
Press-forming of paperboard has been previously studied by several authors. A point of interest regarding gas tight heat sealing of the packages are the creases in the package. The objective of this article was to study and compare different microscopic imaging methods to research an optimal imaging method for the formation of creases in the press-forming process of polymer coated paperboard trays. The studied methods were: Scanning electrode microscopy (SEM), X-ray Microtomography, Optical light microscopy and Polarized light microscopy. All four tested methods delivered clear images. Casting of the samples in an acrylic resin and light microscope imaging was found ...
Cavitation And Puncture For Mechanical Measurement Of Soft Solids, 2015 University of Massachusetts - Amherst
Cavitation And Puncture For Mechanical Measurement Of Soft Solids, Sami Fakhouri
Doctoral Dissertations 2014-current
Gels and other soft elastic networks are a ubiquitous and important class of materials whose unique properties enable special behavior, but generally elude characterization due to the inherent difficulty in manipulating them. This work focuses on understanding and utilizing large, local deformation and failure in soft solids for characterization of the mechanical properties of otherwise inaccessible or nonmanipulable materials. Cavitation Rheology (CR), a pioneering mechanical measurement technique in this regard, where local material failure is imposed and monitored at the tip of a pressurized needle, serves a central role in this thesis. First, CR is used to make in vivo ...
Electrochemical Capture Of Co2 From Natural Gas Using A High-Temperature Ceramic-Carbonate Membrane, 2015 University of South Carolina - Columbia
Electrochemical Capture Of Co2 From Natural Gas Using A High-Temperature Ceramic-Carbonate Membrane, Jingjing Tong, Lingling Zhan, Jie Fang, Minfang Han, Kevin Huang
This study reports the first investigation of using a ceramic-carbonate dual-phase membrane to electrochemically separate CO2 from a simulated natural gas. The CO2 permeation flux density was systematically studied as a function of temperature, CO2 partial pressure and time. As expected, the flux density was observed to increase with temperature and CO2 partial pressure. Long-term stability test showed that flux density experienced an initial performance-improving “break-in” period followed by a slow decay. Post-test microstructural analysis suggested that a gradual loss of carbonate during the test could be the cause of the flux-time behavior observed.
Amine-Pillared Nanosheet Adsorbents For Co2 Capture Applications, 2015 Northeastern University
Amine-Pillared Nanosheet Adsorbents For Co2 Capture Applications, Hui Jiang
Chemical Engineering Master's Theses
Amine-functionalized solid adsorbents have gained attention within the last decade for their application in carbon dioxide capture, due to their many advantages such as low energy cost for regeneration, tunable structure, elimination of corrosion problems, and additional advantages. However, one of the challenges facing this technology is to accomplish both high CO2 capture capacity along with high CO2 diffusion rates concurrently. Current amine-based solid sorbents such as porous materials similar to SBA-15 have large pores diffusion entering molecules; however, the pores become clogged upon amine inclusion.
To meet this challenge, our group's solution involves the creation of ...
Microanalysis Of Polymer Chain Diffusion In Heat Seals, 2015 Clemson University
Microanalysis Of Polymer Chain Diffusion In Heat Seals, Russell Cooper
Heat sealing is an integral method for the closure and protection of packaging. Previous work has shown that seal strength is developed by the interdiffusion of polymer chains within heat seals. Heat seals were made between two dissimilar materials. Poly(ethylene-co-acrylic acid) (EAA) was heat sealed to ionomer. Diffusion within the EAA-ionomer heat seals was estimated. The diffusion estimates were then related to resulting seal strength in the EAA-ionomer sealant system. Heated tooling sealing was utilized to make heat seals at 40 psi (275.79 kPa), 0.5 seconds, and a range of temperatures between 180˚F (82.22˚C ...
Fabrication And Characterization Of Magnetic Nanoparticle Composite Membranes, 2015 Clemson University
Fabrication And Characterization Of Magnetic Nanoparticle Composite Membranes, Akeem Cruickshank
To effectively and accurately deliver drugs within the human body, both new designs and components for implantable micropumps are being studied. Designs must ensure high biocompatibility, drug compatibility, accuracy and small power consumption. The focus of this thesis was to fabricate a prototype magnetic nanoparticle membrane for eventual incorporation into a biomedical pump and then determine the relationship between this membrane deflection and applied pneumatic or magnetic force. The magnetic nanoparticle polymer composite (MNPC) membranes in this study were composed of crosslinked polydimethylsiloxane (PDMS) and iron oxide nanoparticles (IONPs). An optimal iron oxide fabrication route was identified and particle size ...
Synthesis And Characterization Of Chemically Functionalized Shape Memory Nanofoams For Unattended Sensing Applications, Anna Paola Soliani
The work in this dissertation is devoted to the synthesis and characterization of novel materials for off-line unattended sensing: shape-memory grafted nanofoams. The fabrication process and characterization of highly efficient, polymeric nanosensor element with the ability to selectively detect analytes and retain memory of specific exposure events is reported. These shape memory nanofoams could potentially act as efficient and highly sensitive coatings for evanescent waveguide-based optical monitoring systems. On exposure to specific analytes, the polymeric coatings locally change their internal structure irreversibly at the nanolevel, affecting the local optical properties such as refractive index. Currently, enrichment polymer layers (EPLs) are ...
Customizing Fiber Spinning Approaches For Polymer/Nano-Carbon Composites, 2015 Northeastern University
Customizing Fiber Spinning Approaches For Polymer/Nano-Carbon Composites, Kenan Song
Mechanical Engineering Dissertations
Among the many potential applications of nano-carbon (nC), their ability to improve stiffening, strengthening, and toughening mechanisms in polymeric materials has been given considerable attention due to the excellent mechanical properties, and low density of these graphitic materials. The approaches toward designing composites have provided numerous opportunities for the invention of new materials for applications requiring high-strength and high-modulus. Precise control of processing factors including (i) preserving intact nC structure, (ii) uniform dispersion of the nC in polymers, (iii) effective filler-matrix interfacial interactions, and (iv) alignment/orientation of the nC and/or polymer chains all can contribute to the superior ...
Size Effects In Human Visual Inspection For Micro/Meso Scale Parts, 2015 University of Nebraska-Lincoln
Size Effects In Human Visual Inspection For Micro/Meso Scale Parts, Sri Harsha Kavuri
Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research
Visual inspection has been a major method of quality control in conventional manufacturing processes for the last fifty years. Utilizing trained human inspectors to perform this visual inspection has been the most effective means of maintaining quality control. Extensive research has been performed to understand the factors that influence the human inspection process.
In the recent years, there has been a significant emphasis on manufacturing at the smaller end of the size-spectrum such as Micro and Meso scale manufacturing. Quality control at becomes a challenging task due to the extremely small sizes. Several automated visual inspection techniques have been proposed ...
Nanohub.Org: A Gateway To Undergraduate Simulation-Based Research In Materials Science And Related Fields, Tanya A. Faltens, Peter A. Bermel, Amanda Buckles, K Anna Douglas, Alejandro H. Strachan, Lynn K. Zentner, Gerhard Klimeck
Birck and NCN Publications
Our future engineers and scientists will likely be required to use advanced simulations to solve many of tomorrow's challenges in nanotechnology. To prepare students to meet this need, the Network for Computational Nanotechnology (NCN) provides simulation-focused research experiences for undergraduates at an early point in their educational path, to increase the likelihood that they will ultimately complete a doctoral program. The NCN summer research program currently serves over 20 undergraduate students per year who are recruited nationwide, and selected by NCN and the faculty for aptitude in their chosen field within STEM, as well as complementary skills such as ...
Treatment Of A Copper-Rich Gold Ore By Cyanide Leaching, Ammonia Pretreatment And Ammoniacal Cyanide Leaching, Ahmet Deniz Bas, Elif Koc, Ersin Y. Yazici, Haci Deveci
Ahmet Deniz Bas
No abstract provided.