RHEOLOGICAL BEHAVIOR OF LOW-RANK COAL-WATER SLURRIES

The rheological behavior of low-rank coal-water slurries was studied using a Brookfleld Rheolog viscometer. A Sarpy Creek subbituminous coal from Montana, with particle sizes ranging from 0.044 mm to 0.223 mm, was used. The solids concentration in the slurry varied from 15 to 65 weight % and the temperature was maintained constant at 82°F. The rheological behavior of the slurry made from as received coal was compared with that of the slurry made from hot water dried coal

Coal-water slurries, made from both as received and hot water dried coal exhibited pseudoplastic behavior. The shear stress was found to be related to the shear rate by the power law model. As expected, the apparent viscosity was found to increase sharply with solids loading. It was also observed that the apparent viscosities of the slurries made from hot water dried coal were lower than those made from as received coal.     

Preparation of Ceramic Well Plates for Combinatorial Methods Using the Morphogenic Effects of Droplet Drying

When droplets of a ceramic suspension dry on a non-wetting substrate, powder migrates to the periphery and builds there a wall of powder. This intriguing phenomenon, which is a nuisance in some processes, can be used to make arrays of ceramic wells on a ceramic substrate. These wells can, after sintering, be used to hold ceramic samples made from powder by controlled mixing of ceramic inks or could be made from ceramics that act as heterogeneous catalysts and used to hold reactants. The well plates can even be made from electrically conducting ceramics so that electrical property measurements can be made with a ground electrode.     

RHEOLOGICAL BEHAVIOR OF LOW-RANK COAL-WATER SLURRIES

The rheological behavior of low-rank coal-water slurries was studied using a Brookfleld Rheolog viscometer. A Sarpy Creek subbituminous coal from Montana, with particle sizes ranging from 0.044 mm to 0.223 mm, was used. The solids concentration in the slurry varied from 15 to 65 weight % and the temperature was maintained constant at 82°F. The rheological behavior of the slurry made from as received coal was compared with that of the slurry made from hot water dried coal

Coal-water slurries, made from both as received and hot water dried coal exhibited pseudoplastic behavior. The shear stress was found to be related to the shear rate by the power law model. As expected, the apparent viscosity was found to increase sharply with solids loading. It was also observed that the apparent viscosities of the slurries made from hot water dried coal were lower than those made from as received coal.     

The manufacture of microporous membranes and their structure and properties

Microporous membranes suitable for use in ultra- and microfiltration can now be made from a wide range of inorganic and organic materials. Inorganic membranes are made by methods derived from practices that are standard in the ceramics industry. Organic membranes are made from synthetic and modified natural polymers either in the dry state by exploiting anisotropic mechanical properties or from solutions of the polymer by one of the several versions of the phase inversion process. Thanks to the good understanding of the thermodynamic and kinetic properties of polymer-liquid systems resulting from 50 years of careful research, the morphology of asymmetric membranes made by phase inversion can be controlled in fair detail. This short article surveys the methods of manufacturing membranes in relation to their structures.     

Formation of Jets by Shaped Charges with Metal Powder Liners

The characteristics of shaped charges with metal powder liners for perforating borehole pipes are described. The liners were manufactured using powder metallurgy technology. Two types of powder liners were made: a homogeneous one made of copper powder and a heavy one made of copper and tungsten powder blend. Laminar liners consisting of two layers made from powders of different densities were also examined. X‐ray pulse technique was applied to research the process of jet stream formation. Radiograms revealed the discontinuous (discrete) structure of jets formed from powder liners. The corresponding computer simulations of jet formation are presented.     

复合材料汽车制动缸的成型工艺和模具设计

在对国内EX1015型制动缸进行分析研究的基础上,进行了复合材料汽车制动缸的材料设计、成型工艺研究和模具设计,完成了复合材料制动缸样件的制造。为建立复合材料汽车制动缸工业化生产提供理论和试验基础,为汽车行业零部件复合材料化提供有实用价值的参考。     

Role of mercerization of the bamboo strips on the impact properties and morphology of unidirectional bamboo strips–novolac composites

Bamboo strips were mercerized with varying concentrations of NaOH (10, 15, 20, and 25%). Impact test was made on composites made from the untreated as well as from the mercerized strips. Works of fracture for all the composites were evaluated and it was observed that the fracture energy undergoes an increase from composites made of untreated bamboo strips to those made from mercerized bamboo strips. Mercerization removed alkali sensitive material from the bamboo matrix and it leads to more cellulose fibril pull‐out from the lignocellulosic composites, which plays a great role in improving the work of fracture value. POLYM. COMPOS., 28:57–60, 2007. © 2007 Society of Plastics Engineers     

采用压块工艺试制煤质颗粒活性炭

采用六个原煤样品和一种硬煤沥青制成一系列压块活性炭试样,分析了它们的常规吸附性能以及孔结构,并与美国产CalgonF400和日本产Mitsui008活性炭样品做了对比分析,结果表明,用神府长焰煤、山西主焦煤和硬煤沥青制成的YK-4活性炭试样的各项性能,尤其是孔结构,已达到CalgonF400商用炭水平。     

Dust loading on electrostatitically charged filters in a standard test and a real HVAC system

The efficiency and pressure drop of filters made from synthetic fibres carrying electrostatic charges and filters made from uncharged glass fibres were measured repeatedly for more than 19 weeks in operating HVAC systems. Results showed efficiency reductions as large as 40% for the filters made from charged fibres whereas the efficiency of filters made from uncharged fibres changed little.Clean filters were sent to a testing laboratory for efficiency measurements according to ASHRAE Standard 52.2-1999. When the filters experienced accelerated dust loading according to the ASHRAE procedure, the efficiency of both the glass and synthetic fibre filters increased. Efficiency reductions like those observed for the charged filters during actual use were not replicated by this standard test.     

Performance of polysulfone/carboxylated polysulfone membranes

Membranes were made from miscible blends of polysulfone (PSf) and carboxylated polysulfone (CPSf) having an average of 0.45 and 0.87 ? COOH groups per repeated unit. Membranes made from PSf and CPSf alone showed low separation for NaCl, glucose, polyethylene glycol (PEG) of various molecular weights and bovine albumin, from aqueous solutions under an applied pressure of 50 psig and higher. Membranes made from PSf/CPSf of varied blend composition showed higher separation factors for the above solutes. Highest separation was observed in membranes made from an 80/20 wt% PSf/CPSf 0.45 blend, which yielded a separation factor of 0.60 for NaCl, 0.97 for glucose, 0.98 for PEG and 0.99 for bovine albumin under an applied pressure in the range 50–150 psig. This higher performance is believed to be a result of a synergism between PSf and CPSf 0.45 to give a membrane morphology unique among the PSf/CPSf membranes.