ABSTRACT:Recently, polymer-clay hybrid materials have received considerable attention from both a fundamental research and application point of view.1-3 This organicinorganic hybrid, which contains a nanoscale dispersion of the layered silicates, is a material with greatly improved physical and mechanical characteristics. These nanocomposites are synthesized through in situ polymerization or direct intercalation of the organically modified layered silicate (OLS) into the polymer matrix. Thus, understanding the relationship between the molecular structure and the thermal stability (decomposition temperature, rate, and the degradation products) of the OLS is critical. In this study, modern thermal analysis techniques combined with infrared spectroscopy and mass spectrometry (TGA-FTIR-MS) were used to obtain information on the thermal stability and degradation products of organic modified clay. Furthermore, the thermal and mechanical properties of clay-filled PMMA nanocomposites were determined by using TGA and DSC.
Unmanned combat aerial vehicle (UCAV) path planning is a fairly complicated global optimum problem, which aims to obtain an optimal or near-optimal flight route with the threats and constraints in the combat field well considered. A new meta-heuristic grey wolf optimizer (GWO) is proposed to solve the UCAV two-dimension path planning problem. Then, the UCAV can find the safe path by connecting the chosen nodes of the two-dimensional coordinates while avoiding the threats areas and costing minimum fuel. Conducted simulations show that the proposed method is more competent for the UCAV path planning scheme than other state-of-the-art evolutionary algorithms considering the quality, speed, and stability of final solutions.
Although the Clean Air Mercury Rule (CAMR) was recently vacated by the District of Columbia Court of Appeals, efficient mercury (Hg) capture is still an important topic for the coal-fired power plant industry. Several states have Hg emission regulations that are even more stringent than CAMR guidelines. All coals contain Hg, which is released during combustion. Significant research efforts have been made to capture this toxic element before it is released to the atmosphere where it can stay suspended and travel for great distances. A variety of approaches have been examined, among which the injection of sorbent materials such as powdered activated carbon (PAC) is the current method of choice. The work presented here examined the mercury capture capability of various carbon substrates decorated with metal nanoparticles when injected as sorbents. Sorbent injections were carried out in a Hg in air mixture for laboratory-scale screening and in a real flue gas at a coal-fired power plant. It was found that palladium-decorated carbon substrates showed excellent mercury capture capabilities, with total efficiencies greater than 90% in laboratory-scale tests. In the real flue gas, the total efficiency was on the order of ∼60%, comparable to the benchmark commercial sorbent Darco Hg-LH, a brominated PAC, although the tested adsorbents had much lower surface areas. The results of this study are presented herein. Novel mercury capture from a coal-fired flue gas was achieved using carbon substrates decorated with palladium nanoparticles.
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