Advanced Materials Research Vols. 476-478

Abstract: The structure and properties of iron-rich magnesia-spinel composite prepared using sintered iron-rich magnesia and MgO-rich spinel for burning zone of cement rotary kiln were analyzed. The results show that fine-grained magnesioferrite precipitation and magnesiowustite improved the flexibility of magnesia. The formation of Mg (Al,Fe)2O4 reaction rim between iron-rich magnesia and MgO-rich spinel by inter-diffusion reaction of Fe3+ and Al3+ improved the direct-bonded degree and high temperature strength. At high temperature, Fe3+ diffused into the grain of periclase of MgO-rich spinel and was precipitated in the from of magnesioferrite during cooling, which strengthened the structure flexibility of MgO-rich spinel. Iron-rich magnesia-spinel composite had a good adhesion property to clinker because of the uniform distribution of FeOn. Under the same content of Al2O3 and Fe2O3, the iron-rich magnesia-spinel composite had higher hot modulus of rupture, better thermal shock resistance and adhesion property to clinker compared to MgO-spinel composite and MgO-hercynite composite.

Abstract: Liquid mulching film was prepared with technical gramineae lignin from waste pulping liquid via hydroxymethylation and then cross-linking reaction with urea or aromatic ring of lignin. Results showed the amount of lignin added had an influence on the property, viscosity and water resistance of liquid film material. This influence was little when lignin dosage was less than 30%, but turned apparent when lignin dosage was higher than 30%. The optimum lignin quantity was 30%. The growth of plant was accelerated when the concentration of liquid film material was around 1000 mg/L. Both planstic and liquid mulching film could improve soil temperature, the result of liquid film was a little worse than that of plastic film, but was better than the control. The optimum lignin dosage was 30% which had the best heat incubation effect.

Abstract: Nanoscale titanium dioxide (TiO2) has been fabricated through a sound sol-gel method at room temperature with Tetra-n-butyl Titanate as the precursor, and the particles are characterized by XRD and TEM techniques. The results manifest that the as-prepared TiO2 is amorphous with the anatase structure and its size is around 33.2nm. Five factors, including dosage of TiO2, initial concentration of diesel, pH value, photocatalytic degradation reaction time and the presence of H2O2, are considered in the diesel degradation experiments. An orthogonal test is carried out to optimize the photocatalytic degradation of diesel pollutants based on the single-factor experiments. It reveals that when the dosage of TiO2 is 1.0g/L, the initial concentration of diesel is 0.5g/L, pH value is 6, the reaction time is 4h and the H2O2 dosage is 0.09%, the removal rate of diesel pollutants can up to 88%. Besides, the influence of each factor on removing diesel can be arranged in decreasing order: initial concentration of diesel> photocatalytic reaction time> pH value> TiO2 dosage> H2O2 dosage.

Abstract: The objectives of the current study involve in situ depositing treatments of calcium carbonate particles onto bamboo fibers through the ionic reaction of sodium carbonate and calcium chloride aqueous solution at varied bath temperatures, and their impacts on surface features, wettability and tensile properties of single bamboo fibers. Field emission scanning electron microscopy was employed to characterize surface morphology of fibers. The wettability of bamboo fibers was evaluated by optical contact angle measurement instrument. The results show that nanoparticles and submicron particles grew into the wrinkles and micropores of fibers, the size, morphology and adsorbance of which were distinctively varied at different bath temperatures. The highest calcium carbonate adsorbance (2.34%) was obtained at 25°C. Besides, the mean values of contact angles increased and the variations within group were reduced as the loading percentage of particles rose, which might be due to reduced hydrophilic groups after coatings of calcium carbonate particles. The treatments were approved to enhance tensile properties of single bamboo fibers, comparing to the average tensile strengh and modulus of elasticity of the untreated, those of the treated bamboo fibers with the biggest calcium carbonate loading were higher by 30.50% and 32.71% respectively. It’s proved that the precipitating treatment is a useful method to densify and hydrophobize bamboo fibers and smooth out cell wall defects. What’s more, it provide explanations for improvements of physical and mechanical properties of paper and fiber reinforced plastic composites filled with inorganic nanoparticles.

Abstract: In this paper ,the properties of akund fiber, growing at the altitudes of 813m, 1080m and 1153m from August to October were studied, respectively.The influences of altitude, month, fruit size and different parts of the fruit on the properties of akund fiber were also analyzed. It was found that the altitude and fruit size had a significant correlation coefficient with the property of akund fiber, while the influence of month on the property of akund fiber was not obvious. The properties of the fiber in different parts of the fruit were also different.The results will be beneficial to planting, harvesting, processing and exploiting this fiber.

Abstract: Semiconductor ZnO nanocrystal has been synthesized by a sonochemical method and characterized by XRD and SEM techniques. The results indicate that the as-prepared ZnO is of hexagonal wurtzite structure. The photocatalytic degradation of diesel pollutants in seawater is investigated by utilization of ZnO in simulated diesel-polluted seawater exposed to UV irradiation. In the experiment, the influences of ZnO dosage, initial concentration of diesel, pH value, photocatalytic degradation reaction time and the presence of assistance oxidant peroxide, respectively, on the diesel pollutants removal from seawater are investigated. A systematic optimization study is carried out through a orthogonal test on the basis of the results of the single-factor experiments. It reveals that when the experiment is undertaken under the very condition: the ZnO dosage is 1g/L, the initial concentration of diesel 1g/L, the pH value 7, the reaction time 3h and the concentration of peroxide 0.16%, the removal rate of diesel pollutants in seawater is expected to reach 84 %.

Abstract: According to the special characteristics of akund, for example ,high straightness, low strength and easy to fracture , the conclusion got from this paper which is different from traditional fiber carding process is the carding processing length of akund should be longer than the main length of the fiber instead of equality, then the assumption when the carding length is longer than the main length of the main length of akund ,the sliver of the carding will have the lowest short fiber and neps content is advanced, at last, a series of experimental tests prove the conclusion.

Abstract: In order to understand the structure and properties of lotus fibers to provide theoretical basis for developing lotus fiber fabric, the research on chemical components, morphological structure, aggregation structure and mechanical properties of nature lotus fiber is implemented by chemical quantitative analysis, scanning electron microscope, infrared spectra, X-ray diffraction analysis and so on. The result is shown. First, lotus fiber is consist of cellulose, hemicellulose, fat waxy, lignin, ash, pectin, hydrotrope, amino acids and so on, where cellulose is the main ingredient. The lotus fiber, showing ribbon spiral revolving structure vertically, has clearly imperceptible cross striation, and is bundle fiber composed of many monofils. Then, the cross-sectional of lotus monofil is circular or similar to circular. Lotus fiber is typical cellulose I structure with 48% crystallinity and 60% orientation. The density, fineness and moisture regain of lotus fiber is respectively 1.1848 g/cm3, 1.55 dtex, 12.32%. Lotus fiber is high strength and low stretch fiber with initial modulus 146.81 cN/dtex, breaking strength 3.44 cN/dtex and breaking elongation 2.75%.

Abstract: Chlorophenols (CPs), a group of recalcitrant and toxic pollutants, are widespread in the environment and threating human health. The environment-friendly technology, UV irradiation, could efficiently destruct CPs. The study investigated the influence of solution pH and positions and number of substituted chlorine atoms on photodegradation process of CPs, and also studied the photodegradation pathway. It found that the photodegradaton process of CPs was highly dependent on solution pH, and higher pH favored the degradation. The photodegradation processes agreed well with the pseudo-first order kinetics, and para- and ortho- positions and lower chlorination degree were more favorable for photodegradation of CPs. Most of the chlorine atoms were released as chloride ions, and suggest that the cleavage of the C-Cl bond occurred during the photodegradation process. It will provide some guidance for efficient treatment of CPs in water.

Abstract: The microstructure, surface morphology, compression properties, deformation behaviour and strain hardening exponent of as-cast and as-extruded AZ31 Mg alloy after different annealing treatments were investigated. The results show that the compression properties are great different between cast AZ31 alloy and extruded AZ31 alloy. Extruded AZ31 alloy is discontinuous yield and on the surface no signs of damage have been observed; on the contrast, cast AZ31 alloy is continuous yield and shows wavy patterns, and the surface cracks can be easily found. In addition, there is a linear relationship between the strain hardening exponent in first deformation stage and the yield ratio. Further more, the twinning mechanism plays very different role in cast AZ31 alloy and extruded AZ31 alloy.