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De-Yi Wang Yun Liu Xin-Guo Ge Yu-Zhong Wang Anna Stec Bhaskar Biswas T. Richard Hull Dennis Price 《Polymer Degradation and Stability》2008,93(5):1024-1030
Polyethylene (PE) was treated with various formulations containing an intumescent fire retardant, which consists of melamine phosphate (MP), pentaerythritol (PER) and ammonium polyphosphate (APP), and one or none of following metal chelates: CuSAO, CoSAO and NiSAO. The behaviour of this intumescent system can be enhanced significantly by the addition of small amounts (0.2%) of metal chelate (CuSAO, CoSAO and NiSAO). The thermal stabilization, burning behaviour and char formation of the fire retardant PE system have been investigated by TGA, LOI, UL-94 test, SEM and cone calorimetry. All formulations studied provide good fire retardant behaviour, with LOI ≥ 27.4 and UL-94 V-0 rating. TGA results present more complicated thermal decomposition behaviour after the addition of small amounts (0.2%) of metal chelate when compared to that of PE-IFR. Cone calorimetry of PE-IFR–metal chelate (PE-IFR–CuSAO, PE-IFR–CoSAO and PE-IFR–NiSAO) shows a very significant decrease in HRR, PHRR, ML, THR and a very significant improvement of TTI compared to samples without metal chelate. Furthermore, SEM and photographs of the char layer show that the char layer from PE-IFR–metal chelate has a compact and tough char structure compared to the open porous char layer produced by sample without metal chelate. 相似文献
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Multiple objective combinatorial optimization problems are difficult to solve and often, exact algorithms are unable to produce
optimal solutions. The development of multiple objective heuristics was inspired by the need to quickly produce acceptable
solutions. In this paper, we present a new multiple objective Pareto memetic algorithm called PMSMO. The PMSMO algorithm incorporates an enhanced fine-grained fitness assignment, a double level archiving process and a local search procedure
to improve performance. The performance of PMSMO is benchmarked against state-of-the-art algorithms using 0–1 multi-dimensional multiple objective knapsack problem from the
literature and an industrial scheduling problem from the aluminum industry. 相似文献
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On the basis of rigorous analysis supported by numerical computation, a systematic study is presented to locate and examine chaotic Kolmogorov flows resulting from the interaction of a basic steady-state flow and oscillatory modes. Referenced to suitably chosen initial conditions of the Kolmogorov flow model, these oscillatory modes are derived from the equation linearized around the basic steady-state flow. The numerical experiments provide insight into the transition process from secondary self-oscillation flows or secondary steady-state flows to chaotic Kolmogorov flows. 相似文献
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De-Yi Wang Yun Liu C. Perdomo Artiles Dennis Price 《Polymer Degradation and Stability》2007,92(8):1592-1598
A reactive extrusion technology was adopted to synthesize a flame retardant (ER), based on the esterification of melamine phosphate and pentaerythritol. The ER imparts good flame retardancy and non-dripping for polyethylene (PE) when combined with ammonium polyphosphate to yield an intumescent polyethylene (PE-IFR). The performance of this intumescent system has been enhanced by the addition of small amounts (0.2%) chelated copper(II)salicylaldehyde (CuSA) and salicylaldoxime, (CuSAO). The thermal stabilization and burning behaviour of the flame retardant PE system have been investigated by TGA, LOI, the UL-94 test and cone calorimetry. All formulations studied provide good flame retardant behaviour, with LOI ≥ 27.4 and UL-94 V-0 rating. The onset of decomposition in TGA for flame retarded PE (PE-IFR, PE-IFR-CuSA and PE-IFR-CuSAO) commences at lower temperature than that of PE with release of blowing agent, but continues to a higher temperature, leaving a greater residue. Significant differences have been observed in burning behaviour using cone calorimetry, between flame retarded PE (PE-IFR, PE-IFR-CuSA and PE-IFR-CuSAO) and PE, showing decreases in HRR, PHRR, MLR, FIGRA and CO emission. 相似文献