文章以粒径为5 mm的聚乙烯醇(PVA)凝胶颗粒为生物载体,研究其对厌氧污泥颗粒化进程及反应器运行效果的影响。在PVA颗粒污泥初成体形成的情况下,UASB反应器连续运行74 d。试验结果表明:经过32 d的培养,得到沉降性能优良的PVA颗粒污泥,反...文章以粒径为5 mm的聚乙烯醇(PVA)凝胶颗粒为生物载体,研究其对厌氧污泥颗粒化进程及反应器运行效果的影响。在PVA颗粒污泥初成体形成的情况下,UASB反应器连续运行74 d。试验结果表明:经过32 d的培养,得到沉降性能优良的PVA颗粒污泥,反应器COD去除率高达97%,容积负荷由1.05 kg COD·m-3d-1提升至13.33 kg COD·m-3d-1,水力停留时间由35 h缩短至8 h;运行结束时,COD去除率稳定在90%左右,容积负荷达到13.54 kg COD·m-3d-1。通过扫描电镜观察到成熟PVA颗粒污泥外表面丝状菌上交联生长着杆菌、球菌,内部主要附着丝状菌。展开更多
Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle ti...Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle times and solvent swelling media on the swelling properties of PVA saline gel were investigated. The result show that the electrolytical ions have great effect on the swelling behavior of PVA saline gel. The equilibrium swelling ratio of PVA saline gel in aqueous swelling media is larger than that in saline swelling media. Also, the equilibrium swelling ratios of PVA saline gel in aqueous and in saline media decrease with the increase of gel concentration and the increase of freezing and thawing cycle times. The decreasing speed of equilibrium swelling ratio with the increase of freezing and thawing cycle times of PVA gel in distilled water is faster than that in physiological saline. The swelling kinetic equation can sufficiently describe the swelling behavior of PVA physiological saline gel.展开更多
Partially replacing polyvinyl-alcohol(PVA)fibers with polypropylene(PP)fibers in strain-hardening cementitious composites(fiber hybridization)modify certain mechanical properties of these materials.The hybridization b...Partially replacing polyvinyl-alcohol(PVA)fibers with polypropylene(PP)fibers in strain-hardening cementitious composites(fiber hybridization)modify certain mechanical properties of these materials.The hybridization based on the introduction of low-modulus hydrophobic polypropylene fibers improves the ductility and the strain-hardening behavior of the cementitious composites containing polyvinyl-alcohol fibers of different types(PVA-SHCC).Pull-out tests indicate that adding PP fibers increases the energy capacity of the hybrid composite with respect to the material containing only PVA fibers under tensile loading,and PP-fiber geometry(i.e.,section shape and length)is a key factor in enhancing the strain capacity.展开更多
文摘文章以粒径为5 mm的聚乙烯醇(PVA)凝胶颗粒为生物载体,研究其对厌氧污泥颗粒化进程及反应器运行效果的影响。在PVA颗粒污泥初成体形成的情况下,UASB反应器连续运行74 d。试验结果表明:经过32 d的培养,得到沉降性能优良的PVA颗粒污泥,反应器COD去除率高达97%,容积负荷由1.05 kg COD·m-3d-1提升至13.33 kg COD·m-3d-1,水力停留时间由35 h缩短至8 h;运行结束时,COD去除率稳定在90%左右,容积负荷达到13.54 kg COD·m-3d-1。通过扫描电镜观察到成熟PVA颗粒污泥外表面丝状菌上交联生长着杆菌、球菌,内部主要附着丝状菌。
文摘Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle times and solvent swelling media on the swelling properties of PVA saline gel were investigated. The result show that the electrolytical ions have great effect on the swelling behavior of PVA saline gel. The equilibrium swelling ratio of PVA saline gel in aqueous swelling media is larger than that in saline swelling media. Also, the equilibrium swelling ratios of PVA saline gel in aqueous and in saline media decrease with the increase of gel concentration and the increase of freezing and thawing cycle times. The decreasing speed of equilibrium swelling ratio with the increase of freezing and thawing cycle times of PVA gel in distilled water is faster than that in physiological saline. The swelling kinetic equation can sufficiently describe the swelling behavior of PVA physiological saline gel.
文摘Partially replacing polyvinyl-alcohol(PVA)fibers with polypropylene(PP)fibers in strain-hardening cementitious composites(fiber hybridization)modify certain mechanical properties of these materials.The hybridization based on the introduction of low-modulus hydrophobic polypropylene fibers improves the ductility and the strain-hardening behavior of the cementitious composites containing polyvinyl-alcohol fibers of different types(PVA-SHCC).Pull-out tests indicate that adding PP fibers increases the energy capacity of the hybrid composite with respect to the material containing only PVA fibers under tensile loading,and PP-fiber geometry(i.e.,section shape and length)is a key factor in enhancing the strain capacity.
