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This work describes how molecular simulation of polymerization reactions can be used to enrich introductory polymer or material science courses to give students a deeper understanding of free-radical chain and stepwise growth polymerization reactions. These simulations have proven to be effective media for instruction that do not require material cost, significant preparation time, safety considerations, or laboratory space. The simulators are free for academic instruction or research and are available online.

A study is presented herein on the simultaneous inverse identification of transient internal heat generation, transient thermal diffusivity, and constant convection coefficients. The formulations of the direct and inverse problems are presented in the context of finite-element analysis and nonlinear optimization, respectively. A real-coded genetic algorithm was used to solve the inverse problem because of the global convergence properties of this optimization technique. It was found through numerical studies that heat generation and thermal conductivity as functions of time can be simultaneously and consistently estimated from sparse sensor information, as long as convection coefficients are known. However, treating convection coefficients as unknown may significantly affect the accuracy of the estimated thermal diffusivity function and to a lesser extent, the accuracy of the heat generation function. The numerical experiments showed, however, that the Biot number can be accurately estimated when the convection coefficients are not well known. These results can have wide and important implications in problems related to monitoring and quality control of structures. CE Database subject headings: Algorithms; Heat transfer; Thermal properties.

Externally bonded fiber-reinforced polymer (FRP) composites represent a simple and economical solution for repairing and strengthening concrete structures. However, the potential for debonding failure in such strengthening systems becomes prominent when FRP-concrete bonds undergo environmental degradation induced by moisture. Low-viscosity Bisphenol A diglycidyl ether (DGEBA)-based epoxy adhesives are most commonly utilized in the engineering practice to bond wet-layup FRP to the concrete surface. This study evaluated the effects of the addition of commercial surface-modified nanosilica (SMNS), core-shell rubber (CSR) nanoparticles, and multi-walled carbon nanotubes (MWCNT) to neat epoxy on the mechanical properties of the adhesive, and strength and durability of FRP-concrete adhesively bonded joints. To determine the effects of environmental degradation, all specimens were subjected to the following environments: control – 23°C at RH 50 ± 10% for 18 weeks; and accelerated conditioning protocol (ACP) – water immersion at 45 ± 1°C for 18 weeks. Under control conditions, nanomodified epoxy exhibited enhanced mechanical properties compared to the neat epoxy. Following ACP, strength, elongation and modulus of elasticity of neat epoxy deteriorated significantly more than that of nanomodified adhesives. The bond strength of neat epoxy adhesive joints degraded most significantly (15%) following ACP, while nanomodified adhesive joints experienced minimal degradation of bond strength. [ABSTRACT FROM AUTHOR]

The article discusses two polymerization simulators that were developed to teach students a visual representation of stepwise growth and free-radical chain polymerizations. The simulators were developed in order to understand microstructures, predict effects and formulate relevant equations. The simulators' target audience and molecular simulation models are discussed. It is suggested that the simulators present an easier learning method that is more contemporary, visual and interactive. Other simulators such as the stepwise growth are also discussed.