Advanced Materials Research Vols. 396-398

Abstract: Air stripping of ammonia is a widely used process for the pretreatment of wastewater. Scaling and fouling on the packing surface in packed towers and a lower stripping efficiency are the two major problems in this process. New patented equipment that is suitable for the air stripping of wastewater with suspended solids has been developed. Air stripping of ammonia from water with Ca(OH)2, was performed in the newly designed gas-liquid contactor, a water-sparged aerocyclone (WSA). The pressure drop of gas phase was investigated in order to know the momentum transfer characteristic of the WSA. It was found that the gas phase pressure drop exhibited a different change tendency compared with the traditional aerocyclone, and could be divided into three characteristic stages, including low pressure drop, pressure drop jump and high pressure drop phases. The three different pressure drop areas corresponds to steady jet, spiral and fogged flow patterns of the liquid phase. The critical value for the air flow rate which caused the mass transfer coefficient to increase rapidly took place at the point where the steady jet was transformed into the spiral flow pattern.

Abstract: In this paper, semi-solid metal (SSM) processing was first applied to fabricate Al-based matrix and diamond composites. A kind of Al-Cu alloy with an adequate solidification range was chosen. Samples of Al-Cu alloys were fabricated by rheocasting with different processing parameters. Specimens of Al-based matrix and diamond composites were fabricated by rheocasting and hot press sintering technology respectively. Microstructures, transverse rupture strength (TRS), hardness and wear resistance were studied. Experimental results revealed that the TRS of the Al-based matrix and diamond composites fabricated by rheocasting increased by 157% and 115% respectively compared to the ones fabricated by hot press sintering technology. The fracture surfaces of the rheocasting specimens exhibited ductile cup and cone behavior as well as strong bonding between the matrix and diamond grits.

Abstract: The paper presents the research on the controlled strain and temperature on the stress strength of martensitic GX12CrMoVNbN9 – 1 in the energy-based approach. The fatigue tests were carried out for five levels of total strain amplitude ac and two temperatures (the room one and 600oC). Performed research has shown that in terms of energy the investigated cast steel is characterized by changes in cyclic properties. Moreover, it has been proved that the temperature of study significantly influences the per-unit value of strain energy. The influence is slight in the area of large strains and gets stronger as the level of cyclic strains decreases.

Abstract: A full color 2.2″ passive matrix organic light-emitting diodes (OLEDs) with 128 (RGB) * 160 pixels was developed. The display features that driving circuit can transform 18 bits gray-scale data from a PC to the OLED panel via a DVI channel. The size of the pixel was 240μm 240μm, while that of mono sub-pixel is 190μm 45μm. The lifetime of panel was estimated over 5000h because of the use of dual-scan driving technology, and the power consumption of the display was 300mw about when the average luminance of panel reach 40cd/m2.

Abstract: In this paper, it has studied membrane fouling experiments at a certain temperature conditions and with untreated tap water as thermal mass, which applied unique multi-layered stacked air-gap membrane distillation module. It has analyzed the original membrane flux and conductivity changes in the experiments, and carried out SEM and EDS analysis before and after acid washed fouling membrane. The results show that: New type membrane module will produce fouling even at lower temperatures. Membrane surface was covered by a lot of uneven accumulation granular pollutants and cuboid crystals, so the mass flux reduced. Fouling membrane washed with 5 % hydrochloric acid solution was removed inorganic scale. The flux recovered to the initial value.

Abstract: The silica-based mesoporous materials were synthesized under normal atmospheric with Cetyl trimethyl ammonium bromide(CTAB) as surfactant, TEOS as silica source and hydrochloric acid as activator. The pore sizes distribution of mesoporous materials were adjusted by organic assistant reagent TMB(1,3,5-three toluol).The materials after and before TMB addition were characterized through XRD and IR. The results showed that the materials have regular hexagonal mesoporous structure. The structure is more regular and pore size is more bigger after TMB added.

Abstract: The effect of final cooling temperature on the mechanical properties of a water cooled Mn-series low carbon bainitic steel as 8Mn2SiNb has been investigated in this paper. The results indicate that the optimum final cooling temperature is 450 °C, followed by air cooling to room temperature. Compared with air cooling, the condition of water cooling to 450 °C increases the tensile strength and yield strength about 13.3% (From 805MPa to 929MPa) and 59.0%(From 464MPa to 741MPa) respectively, remaining 21.5% elongation and 151J toughness. SEM observation reveals that the microstructure of the steel after water cooling to 450 °C is mainly granular bainite +lath martensite +refined grain boundary allotriomorphic ferrite (FGBA). Compared with air cooling, the condition of water cooling to 450 °C increases the volume fraction of strengthening phase (M-A island) from 28.2% to 38.1%.

Abstract: Nanostructured WC-12Co coating was prepared by means of High Velocity Oxygen Fuel (HVOF) spraying technology in this research. The erosion wear experiment system was developed to simulate the working condition to study the erosion wear properties. The corundum sand with main composition of Al2O3 and quartz sand with main composition of SiO2 were used to investigate the effects of sand variety on the erosion wear properties. The erosion wear failure mechanism of the coatings was also analyzed. The results show that the failure mechanism of the coating eroded by corundum sand is cracking between WC grains, while for the coating eroded by quartz sand, the failure mechanism is microcutting and microploughing.

Abstract: Epoxidized Natural Rubber is prepared with latex processing technology. The relationships of the epoxidation with the reaction times and temperature were investigated. The structure of ENR was characterized by Fourier transform-infrared spectroscopy (FIIR). It is found that, the by products, ring-open components increases with the reaction temperatures and the reaction times. It is found that as the level of epoxidation increased, the number of tetrahydrofuran ring increased.

Abstract: Blue-emitting phosphors Sr₃MgSi₂O₈:Eu²⁺ with high brightness were prepared by gel-combustion method under weak reductive atmosphere. The as-synthesized phosphors were investigated by X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and Fluorescence spectrophotometer. The results indicate that Sr₃MgSi₂O₈:Eu²⁺ phosphors have orthorhombic crystal structure. The excitation spectrum is a broad band and with two peaks at around 414 nm and 400 nm respectively. The emission spectrum is also a broad band, and the emission peak is at about 460 nm. It’s ascribed to typical transition from 4f5d to 4f of Eu²⁺. Besides, it is found that the dosage of urea, the reductive temperature and time, etc. have great effects on luminescence intensity of Sr₃MgSi₂O₈:Eu²⁺ phosphors. The optimum process conditions were confirmed.