Advanced Materials Research Vol. 658

Abstract: The degradation behaviour of an anhydride-cured bisphenol A diglycidyl ether (DGEBA) epoxy resin in near-critical water was studied in this paper. The experiments were performed in a stainless steel reactor (100ml) without stirring. Epoxy resin could be decomposed successfully at 270°C for 30 min. The degradation rate of epoxy resin increased with an increase in reaction temperature and reaction pressure. The degradation reaction products were characterized by gas chromatography-mass spectrometry (GC-MS). The degradation reaction was associated with the scission of ester and ether bonds which further destabilizes the epoxy network.

Abstract: Surfacing of Fe-Al alloy layer is achieved on the surface of Q235 steel plate by using the twin wire consisting of one aluminum welding wire and one steel welding wire in the shielding of pure argon. When the ER1100 aluminum welding wire of Φ1.6mm and ER50-6 steel welding wire of Φ1.2mm are selected as the master wire and slave wire respectively, with preheating and interlayer temperature reaching 350°C by controlling filling volume of aluminum and steel , the Fe-Al alloy layer featured by well-formed welding line is thus gained with no macroscopic defect. As the mechanical performance testing shows, the shear strength of surface combining surfacing layer and steel substrate is higher than 270MPa. The rupture position is located in surfacing layer and it turns out to be brittle fracture; the micro-hardness of surfacing layer ranges from 320HV to 420HV. Abrasion resistance testing indicates that abrasion resistance of surfacing layer is better than that of base material. According to micro-structure observation, the welding line is a coarsening columnar structure with a great deal of precipitated phase. According to EDAX, the aluminum content of precipitated phase in surfacing layer ranges from 24% to 32% (at), and the steel content ranging from 76% to 68% (at) - it is thus considered a Fe3Al structure through XRD.

Abstract: Polyaniline-paper composite is prepared on a paper template by interfacial polymerization. Using SEM and FESEM, the morphology of PANI on fiber and pores between fibers are inspected based on different polymerization. The flake shape of PANI is formed on fiber surface at the beginning due to electrostatic attraction, while the granular is growing on the pores freely. This flake shape on fiber is changed with 3rd polymerization into granular. When the resistivity is below 100cm/S, linear PANI in pores is growing to the fiber nearby, and PANI network formed. The morphology also confirmed that PANI on fiber only remains on the upside not fully covered surface of fiber. Very few PANI is found inside paper substrate by cross section SEM. The method is discussed also with polyaniline-fiber composite polymerization and in-site paper polymerization.

Abstract: According to Hill’s thermodynamics theory for small system, the effect of small system on the thermal hysteresis activity of type I antifreeze protein ‘HPLC-6’ is discussed in this article. We conclude that when the solution is very dilute, the effect is not visible, and as the concentration increases, the effect becomes more visible than before, and the result also shows that the thermal hysteresis temperature becomes larger when the effect of small system is considered.

Abstract: In order to improve utilization ratio of blast furnace slag (BFS), the study used BFS, cement and building glue to make blast-furnace-slag granular media (BGM) in a non-sintered process. The characterization of BGM was analyzed by physical method, scanning electron microscopy (SEM) and D/max-rA X-ray diffraction (XRD). And the influence of hydraulic retention time (HRT) and air-liquid ratio (A/L) on the removal of average chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) were also investigated. The results indicated that the BGM presented high total porosity, large total surface area and low bulk and apparent density. The BGM reactor showed the good removal efficiency on COD and NH4+-N with HRT of 6 h and A/L of 5:1, which were above 86% and 90%, respectively. Overall, BGM showed good performance as wastewater treatment filter media in biological aerated filters (BAF), whose application is a promising way to use waste blast furnace slag.

Abstract: In order to research welding technology of DX51D+Z cold rolled galvanized steel, using multivariate nonlinear regression orthogonal combination design method, adopted the shear load as quality indicators, counted welding current, electrode force, welding time, squeeze time and the interaction of them as factors, to built the nonlinear regression models, by adopting this model to forecast shearing load. The result shows that this model has high forecast precision.

Abstract: To investigate the nonlinear phenomena of cutting forces when machining difficult-to-machining materials in the high-speed cutting process, system experiments by factorial design and Latin hypercube sampling design were conducted. The cutting force nonlinear characteristics were analyzed in time domain and frequency domain through wave-let analysis and power spectrum analysis. Experiments indicated that in the high-speed milling process, the characteristic curves of primary cutting forces could not strictly maintain their linearity with the variation of cutting parameters, the effect of one cutting parameter on primary cutting forces is sensitive to the combination of cutting parameters, and a lower frequency periodic signal appears when the cutting speed is above 471 m/min (spindle speed is 3000 r/min).

Abstract: In order to improve the surface quality of ultra high strength low alloy steel work-pieces produced by high-speed face milling process, 23-1 factorial design experiment was con-ducted and the residual stress profiles within the surface and subsurface layer of work-pieces were measured. Corresponding empirical models for the residual stress profile were presented and the effects of cutting parameters (cutting velocity, feed per tooth, depth of cut) on characteristics of the residual stress profile were studied. Results show that: with the range of cutting parameters tested, the compressive residual stress profile would be induced below the work-pieces’ surfaces machined by high speed face milling process. Feed per tooth has the critical influence on the characteristics of the compressive stress profile, and the mechanism of residual stress generation will be different when feed per tooth changes in high speed machining process. To obtain higher compressive stress and deeper compressive stress profile depth, larger feed rate and depth of cut are required.

Abstract: Plasma spraying rapid making of functionally graded mold is an effective preparation method. In this paper, finite element method simulation of the plasma spray process a single droplet deformation and matrix effects in the process. Studies have shown that: speed large solidification time is short, more conducive to the formation of the coating; speed large residual thermal stress is small; preheat temperatures are high, the particle flattening effect, The research results will provide theoretic basis for improving spraying coating quality.

Abstract: In order to investigative the effect of mineral particle shapes to breakage rate of ore, basing on discrete element method, comparative grinding experiments were performed separately in a laboratory ball mill under the same conditions of mass and feed by using regular tetrahedron, parallelepiped and sphere as models of mineral particle. This study shows that ore grain shapes have a great influence on breakage rate due to different impact energies in ball mill.