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Articles 1 - 8 of 8
Full-Text Articles in Engineering
Quantitative Analysis And Structural Characterization Of Carbonaceous Pitches, Sourabh Kulkarni
Quantitative Analysis And Structural Characterization Of Carbonaceous Pitches, Sourabh Kulkarni
All Dissertations
Both petroleum pitches and pitches derived from pure polycyclic aromatic hydrocarbons (PAHs) are oligomeric materials that can serve as precursors for a wide variety of advanced carbon materials. The goal of this study was the structural characterization and quantitative analysis of the dominant constituent oligomers and species present in these pitches.
A key requirement for such work is the ability to fractionate these complex mixtures into samples of narrow molecular weight distribution (mol wt; MWD) that can be used as standards. To this end, semicontinuous (or semibatch) dense-gas/supercritical extraction (DGE/SCE) was used to produce monomer, dimer, and trimer fractions of …
Multi-Scale Modeling Of Polymeric Materials: An Atomistic And Coarse-Grained Molecular Dynamics Study, Qifei Wang
Multi-Scale Modeling Of Polymeric Materials: An Atomistic And Coarse-Grained Molecular Dynamics Study, Qifei Wang
Doctoral Dissertations
Computational study of the structural, thermodynamic and transport properties of polymeric materials at equilibrium requires multi-scale modeling techniques due to processes occurring across a broad spectrum of time and length scales. Classical molecular-level simulation, such as Molecular Dynamics (MD), has proved very useful in the study of polymeric oligomers or short chains. However, there is a strong, nonlinear dependence of relaxation time with respect to chain length that requires the use of less computationally demanding techniques to describe the behavior of longer chains. As one of the mesoscale modeling techniques, Coarse-grained (CG) procedure has been developed recently to extend the …
Roles Of Polymer Crosslinking Density And Crystallinity In Regulating Surface Characteristics And Pre-Osteoblastic Mc3t3 Cell Behavior, Kan Wang
Doctoral Dissertations
This dissertation presents material design strategies to investigate cell-biomaterial interactions on specific biocompatible polymers and polymer blends by using mouse pre-osteoblastic MC3T3 cells aiming for potential applications in bone tissue engineering. Chapter 1 reviews some related background knowledge including polymeric biomaterials for tissue engineering, cell-biomaterial interaction, synthetic photo-crosslinkable and degradable polymers, and the effect of surface features on osteoblast cell responses. Chapter 2 presents photo-crosslinkable composites of poly(propylene fumarate) (PPF), an injectable and biodegradable polyester, and methacryl-polyhedral oligomeric silsesquioxane (mPOSS), which has eight methacryl groups tethered with a cage-like hybrid inorganic-organic nanostructure, for bone tissue engineering applications. Blending mPOSS with …
Electron Irradiation Effects On Ferroelectric Copolymer Langmuir-Blodgett Films, Christina M. Othon, Stephen Ducharme
Electron Irradiation Effects On Ferroelectric Copolymer Langmuir-Blodgett Films, Christina M. Othon, Stephen Ducharme
Christina M Othon
The effect of irradiation on the ferroelectric properties of Langmuir-Blodgett films of the copolymer poly(vinylidene fluoride-trifluorethelene) is investigating using 1.26 MeV electrons with dosages from 16 to 110 Mrad. Irradiation causes a systematic decrease in the phase transition temperature, coercive field and polarization of these thin films.
Fiber Formation From The Melting Of Free-Standing Polystyrene, Ultra-Thin Films: A Technique For The Investication Of Thin Film Dynamics, Confinement Effects And Fiber-Based Sensing, Jeremy M. Rathfon
Open Access Dissertations
Free-standing ultra-thin films and micro to nanoscale fibers offer a unique geometry in which to study the dynamics of thin film stability and polymer chain dynamics. By melting these films and investigating the subsequent processes of hole formation and growth, and fiber thinning and breakup, many interesting phenomena can be explored, including the nucleation of holes, shear-thinning during hole formation, finite-extensibility of capillary thinning viscoelastic fibers, and confinement effects on entanglement of polymer chains. Free-standing films in the melt are unstable and rupture due to instabilities. The mechanism of membrane failure and hole nucleation is modeled using an energy barrier …
Determining The Ultimate Strength Of 'Tough Skin', A Glass Fibre Reinforced Polymer Liner, Jan Anton Nemcik, Ian Porter, Ernest Y. Baafi, Jeffery Navin
Determining The Ultimate Strength Of 'Tough Skin', A Glass Fibre Reinforced Polymer Liner, Jan Anton Nemcik, Ian Porter, Ernest Y. Baafi, Jeffery Navin
Faculty of Engineering - Papers (Archive)
Fully encapsulated roof bolts have been proven to confine the roof and rib strata actively, while steel mesh only provides passive support and protection from falling rocks as they dislodge from the roof. To provide better stability of the mine roadway skin, replacement of the steel mesh with a spray on polymer liner is being investigated. Among the many benefits that may be realised by the application of quick setting spray on polymer liners as skin support are an increase in development rates and improved safety for working personnel. Extensive testing of a range of available polymer formulations is currently …
The Behaviour Of Carbon Fibre Reinforced Polymer Confined Concrete Cylinders Under High Temperature Exposure, Butje Alfonsius Louk Fanggi, Muhammad N. S Hadi
The Behaviour Of Carbon Fibre Reinforced Polymer Confined Concrete Cylinders Under High Temperature Exposure, Butje Alfonsius Louk Fanggi, Muhammad N. S Hadi
Faculty of Engineering - Papers (Archive)
This study investigates the effect of temperature on the behaviour of concrete cylinders wrapped with Carbon Fibre Reinforced Polymer (CFRP). The study used nine concrete cylinders in three groups; the first group was exposed to room temperature of approximately 20ºC, the second group was exposed to a cyclic temperature with a temperature range of 20ºC to 70ºC, and the third group was exposed to a prolonged temperature of 70ºC. All cylinders were then tested to failure. The study indicated that ultimate strength of cylinders wrapped with one and two layers of CFRP are significantly unchanged after being exposed to 20ºC …
Bearing Capacity Of A Glass Fibre Reinforced Polymer Liner, Jan Anton Nemcik, Ian Porter, Ernest Y. Baafi, Joshua Towns
Bearing Capacity Of A Glass Fibre Reinforced Polymer Liner, Jan Anton Nemcik, Ian Porter, Ernest Y. Baafi, Joshua Towns
Faculty of Engineering - Papers (Archive)
The development and testing of stiff polymer to be used as part of roof and rib support system for underground mining is discussed. Laboratory tests were conducted to examine the bearing capacity of thin spray polymer liners (TSL) Polymer, which included both puncture test and the optimum size of steel bearing plates. It was found that a 60 mm diameter steel disc carried approximately 60 t, and that a 250 mm diameter steel plate had no major effect on the integrity of the TSL. Further polymer bearing capacity studies on uneven surfaces must be conducted to simulate actual mine site …