Advanced Materials Research Vols. 183-185

Abstract: A simple method for qualitative and quantitative determination of PCB95, 132, 149 and 174 enantiomers in soils and sediments using GC-ECD/MS was proposed. On the promise of good purification efficiency, high recovery and easy operability, H₂SO₄ washing and a multi-layer column filled with 1 g anhydrous sodium sulfate, 2 g 10% silver nitrate-impregnated silica gel, 4 g 3.3% water-deactivated silica gel and 1.5 g anhydrous sodium sulfate were selected as purification procedures. The chromatographic conditions were optimized to obtain the best enantiomeric separation. Complete baseline separations were achieved for PCB95, 132 and 149, as well as approximate baseline separation was obtained for PCB174. This method was proved to have highly satisfactory accuracy, precision and sensitivity with mean recoveries of target PCB enantiomers in range of 71.42−80.12% and RSD<6%. The detection limits of the method were 11.37−25.36 pg•g⁻¹.

Abstract: Most of steel beams in midspan bottom slab are fixed up following the shape of girder bottom edge with both ends anchoring to the bottom slab wedge. Due to the girder of long-span continuous rigid-frame bridge has variable cross section, the shape of steel beams in midspan bottom slab presents a curve opening downward, which does harm to the girder. Arranging steel beams along straight line in the bottom slab with both ends anchoring to the top wedge is better for girder to carry load. The analysis results of two methods analyzed by FEM shows that arranging of straight line lowers the stress of the top edge of girder meanwhile it increases the stress of bottom slab edge. Besides, the method lowers pressure stress and shear stress of the height middle of the girder where the steel beam anchoring and increases the main tension stress reservation which is good for the girder to carry load.

Abstract: Miniemulsion was prepared by means of different ratio of butyl acrylate with vinyl acetate emulsion pressure sensitive adhesive excellent performance. Focused on acrylic acid and vinyl acetate copolymers of different proportions of the glass transition temperature, molecular weight and molecular weight distribution of micro-factors, and build the macroscopic properties of the copolymer glass transition temperature and molecular weight between contacts. The use of APS as initiator under the conditions of the experiment found that with the increase of acrylic, PVC-floor, 180 peel strength composite materials decreased. While the molecular weight of butyl acrylate with the increase of the amount did not change significantly, the initial viscosity of the polymer and 180 º peel strength is improved, but the adhesive holding down quickly.

Abstract: In this experiment, cinnamon oil was used as the raw material to produce a water soluble derivative. Cinnamaldehyde, a major constituent of cinnamon oil, is easy to take place nucleophilic addition with saturated sodium bisulfite aqueous solution and generate sodium hydrogensulfite adduct—cinnamaldehyde hydroxyl sulfonic sodium, which has great water solubility, and the yield was 74.64%. The chemical structure of the product was identified by Fourier Transform Infrared Spectroscopy (FTIR). The anti-fungal activity of the product was determined by paper-disc method with wood decay fungi such as Trametes versicolor, Gloeophyllum trabeum and wood stain fungi such as Aspergillus niger, Paecilomyces Variotii and Paecilomyces lilacinus. The anti-fungal experiment results showed that the product has a little anti-fungal activity for the selected stain fungi, especially Aspergillus niger, but the antifungal activity of the product is not good. It has no anti-fungal activity for Trametes versicolor and only a little activity for Gloeophyllum trabeum. The result indicates that the aldehyde group plays an important role in the anti-fungal activity of cinnamaldehyde. Some derivatives without changing aldehyde group should be focused on in the future.

Abstract: The powder mixed electro-discharge machining (PMEDM) technologies of silicon carbide particle reinforced aluminium matrix composites (SiCp/Al) are researched in this article. SiCp/Al is widely acknowledged as one of the most competitive varieties of metal matrix composites, firstly applied in the aviation, aerospace and military fields, and gradually extended. Because of the hard and brittle SiC particles contained in this material, mechanical machining is difficult, but EDM does have some advantages. To the same kind of moderate volume fraction (45%) SiCp/Al material, a comparative test was conducted using two kinds of processing methods, traditional EDM (the former) and PMEDM (the latter). Effects of the electrical parameters of both processing methods on the material removal rate (MRR) were analyzed and compared. After processing, the surface roughness value of the former is Ra1.386μm while the latter is Ra0.406μm which is only 29.3% of the former. The surface hardness was also tested by the MTS nano indenter: the former is about 1.7GPa, and the latter is about 2.2GPa which is 1.3 times of the former. Finally, to the machined surface, the micro-topography and the component of ‘white point’ were observed and analyzed by using scanning electron microscope (SEM) and energy spectrum respectively. Experiments and investigation results show that the PMEDM has a better performance compared with traditional EDM in improving the roughness, hardness and so on. So PMEDM will have a great potential in the processing of aluminium matrix composites.

Abstract: Xylan preservatives are the new environmental, pollution-free wood preservatives, which are harmless to humans and animals. Using bagasse, rice husk, corn cob, birch and so on as raw materials to extract xylan widely used in industry. The optimal alkaline extracting conditions were: alkali concentration: 12%; ratio of solid to liquid: 1:10; extraction time and temperature were 2h and 100 °C respectively.

Abstract: Put forward a new method to prepare polyaluminium ferric chloride (PAFC). Discuss the effect of starting materials, reaction processes on the leaching ratios of alumina and iron oxide. Application properties were tested. The results showed that both diasporic bauxite and the red mud from gibbsite (RMG) do not need to be baked. In the case of diasporic bauxite, the leaching ratios of alumina and iron oxide reach 4.15% and 78.32% respectively under the conditions that the concentration of hydrochloric acid is 6mol/L, the reaction time is 60 minutes, the reaction temperature is about 109°C, and the way of extracting is two-step extracting. In the case of RMG, the leaching ratios of alumina and iron oxide reach 89.00% and 98.39% respectively under the same conditions. Diasporic bauxite is not a suitable raw material for PAFC synthesizing. The PAFC prepared from RMG was used to treat active black KN-B dye-containing wastewater and the Kaolin-containing wastewater. The maximum depollution ratio is 98.0% and 97.0 % respectively.

Abstract: The color change and bending properties of diapers scrap/PE composite and recycled milk-cartons/PE composite put in the sun environment, the dry and wet environment, and the Xenon Weathering resistant box environment were studied. It showed that: (1) The surface color of the two new WPCs changed greatly in three environment, and affected the appearance; the color change in the Xenon Weathering resistant box environment is much greater than it in the sun environment and the dry and wet environment, (2) The MOE and MOR initially showed decreased trend and then showed an upward trend after test in the sun environment and the dry and wet environment for about six months; The MOE and MOR decreased a lot after put in the Xenon Weathering resistant box environment for 1500h.

Abstract: The argon and carbon dioxide co-injection tests were carried out with low carbon steel melts of 100 kg in a multi-function direct current ladle furnace (DC-LF) equipped with a hollow graphite electrode. It is shown that, the heating rates of the heats with argon or Ar-CO2 injection are higher than that of the normal solid graphite electrode heat. The average heating rate of the heat with argon injection is 1.59 times than that of the normal solid graphite electrode heat. The minimal average heating rate of the heat with Ar-CO2 co-injection is 3 times than that of the latter, and the maximum is 5.51 times. When argon or Ar-CO2 is injected into LF, the electric current isn’t change, but the voltage is lower.

Abstract: In this study, effects of ultrasound processing time, ultrasound power and solid liquid ratio of ultrasonic on pumpkin polysaccharide extraction were investigated. The optimum parameters of extracting pumpkin polysaccharides are obtained by orthogonal test. Antioxidant activity were evaluated by using various established invitro systems, including 1,1-diphenyl-2-picrylhydrazylthe(DPPH•), hydroxyl(•OH) and FRAP system. Results showed that the extraction rate of polysaccharides pumpkin could up to 12.37% which the condition were water as extractant, ultrasonic time is 10min, ultrasonic power is 400w, solid to liquid ratio is 1:20. The polysaccharide raised the total antioxidant capacity in a dose-dependent manner. The results suggested that polysaccharide had direct and potent antioxidant activities.