Thermal Properties of Epoxy-Based Adhesive Reinforced With Nano And MicroParticles For In-Situ Timber Bonding
—CB10TSS thixotropic and room temperature cured epoxy based adhesive specially formulated for in-situ bonding of pultruded rod into timber for repair and strengthening of timber structures. The glass transition temperature for CB10TSS is 31.7ºC which considered low for outdoor exposure. Therefore CB10TSS was modified by reinforcing it with nano-and micro-particles and denoted as Nanopox (CB10TSS/nanosilica), Albipox (CB10TSS/liquid rubber) and Timberset (CB10TSS/ceramics). Thermal properties of epoxy adhesives were studied by using dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). Albipox showed significant improvement in the glass transition temperature but Timberset has the highest Tg, due to high modulus of ceramic particles. A second scan for all the adhesives increased Tg which shows that the room temperature cured adhesives are not fully cross-linked. In DSC scan, typical graphs of heat flow versus temperature able to describe more characteristic of the curing behavior such as a sharp and deep endothermic dip at Tg which corresponds to a rearrangement of the molecules and the wide and shallow endothermic dip at around 100°C is associated with moisture in the adhesive.
Electrical, dynamic-mechanical, thermal and morphological behaviors of epoxy/nano alumina systems
More recently, epoxy/nano alumina composites have become a strenuous topic of research for their electrical, physical and thermal properties due to their capability that could act as electrical insulators. Alumina, which is a hard spherical material, could be an appropriate option for reinforcing epoxy resin since it has properties like high stiffness, significant thermal conductivity and dielectric characteristic. The objective of the current paper is to investigate the influence of nano alumina particles on electrical, dynamic mechanical and thermal properties as well as morphological behavior of the cast epoxy composite. Also the influence of temperature on electrical properties of the composite filled with different content of nano filler is intended to study in this research. To accomplish this purpose, different weight percents of nano alumina were added to the epoxy/silica flour system to measure dielectric strength, loss factor and specific volume resistivity of prepared samples in different temperatures. Also, thermal and dynamic mechanical properties and morphology of the cast epoxy systems were studied. It was realized that electrical properties is more improved in the specimen filled with 5% nano alumina. Furthermore, it was found that thermal properties are strongly affected by dispersion of nano particles in the matrix
Experimental Study for a Double-Glazed Forced-Flow Solar Collector/Regenerator
Experimental study of a double-glazed forced-convection solar collector/regenerator for absorption solar cooling is presented. The south facing experimental solar collector/regenerator with 10 deg slope is located at Kaohsiung, Taiwan at 120{degree}19minutesE longitude and 22{degree}34minutesN latitude. The size of the collector is 1 m wide and 7 m long with an effective regeneration area of 0.9 m by 6 m. Previous study for single-glazed forced-convection solar collector/regenerator operated at the same location has shown to have a best day-average efficiency of 17%. In order to raise the system performance, a double-glazed collector/regenerator is constructed such that air can be preheated in the upper channel flow. The preheated air is then conducted into the lower channel where it contacts with the film flow of solar heated lithium-chloride solution and regenerates the solution by carrying out the evaporated water vapor. The preheated air has lower relative humidity but the same humidity ratio since it is sensibly heated. Therefore, the regeneration driving potential is increased. The present study shows that the best day-average efficiency can reach 20% which increases the feasibility of the open-cycle absorption solar cooling system. Effects of controlling parameters on the collector/regenerator performance are studied, and heat and mass transfer correlationsmore » are also presented for design purposes.« less