Radiation‐processed polychloroprene‐co‐ethylene–propene diene terpolymer blends: Evaluation of blend morphology,miscibility, and physical properties

The miscibility of polychloroprene rubber (CR) and ethylene–propylene–diene terpolymer rubber (EPDM) was studied over the entire composition range. Different blend compositions of CR and EPDM were prepared by initially mixing on a two‐roll mill and subsequently irradiating to different gamma radiation doses. The blends were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, density measurement, hardness measurement, and solvent permeability analysis. The compatibility of the blends was studied by measuring the glass transition temperature and heat capacity change of the blends. The immiscibility of blends was reflected by the presence of two glass transition temperatures; however, partial miscible domains were observed due to inter diffusion of phases. Permeation data fitted best with the Maxwell's model and indicated that in CR‐EPDM blends, EPDM exists as continuous phase with CR as dispersed phase for lower CR weight fractions and phase inversion occurred in 40–60% CR region. It was observed that CR improved oil resistance of EPDM; however, the effect was prominent for blends of >20% CR content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The effect of Al2O3 on sintering and crystallization of MgSiO3-based glass-powder compacts

The influence of Al₂O₃ (8 wt.%) on sintering and crystallization features of glass powders based on magnesium silicate (MgSiO₃) was experimentally determined. The investigated compositions were Y_0.125Mg_0.875Si_0.875B_0.125O₃ and Y_0.125Mg_0.725Ba_0.15Si_0.875B_0.125O₃. For the experiments, glasses in bulk and frit forms were produced by melting in Pt-crucible at 1600 °C for 1.5 h. Glass-powder compacts were sintered at different temperatures between 900 °C and 1100 °C. The evolution of crystalline regime was determined by in situ recording of X-ray diffractograms of fine glass powders at elevated temperatures. The results and their discussion showed that addition of 8 wt.% Al₂O₃ in glass batches affected the thermal properties of the glasses and resulted in MgSiO₃-based glass ceramics well sintered between 900 °C and 1100 °C. In the BaO-free MgSiO₃ glass ceramics, clino- and orthoenstatite crystallize while the presence of BaO favours the formation of hexacelsian.     

基于工艺模拟的污水处理厂数字化实例研究

在对污水处理厂历史监测数据收集、整理和分析的基础上,利用GPS-X软件,建立并校正了污水处理厂工艺模型,同时探索了校正方法。研究结果表明,自养菌最大比生长速率作为污水特征参数,需通过拟合出水的NH3-N浓度变化进行校准。污泥浓度的拟合是一个非常重要的步骤,影响污泥浓度拟合的参数包括进水特征参数(VSS/TSS值、总COD中颗粒惰性组分的占比)、剩余污泥排放量、初沉污泥排放量。