Advanced Materials Research Vols. 143-144

Abstract: In this study, eight water-quality indices, such as temperature, pH, colority, DO, BOD5, CODMn, NH3-N and TP, were monitored based on the water environment of Yulong River- the only landscape river in the central area of Zibo city. The water quality assessments of each individual parameter were performed. Results showed that Yulong River had already been eutrophicated. According to the current water qualities and environmental characteristics of Yulong River, an ecological complex filter plan was proposed to remedy Yulong River.

Abstract: The research shows that the proper acceleration（RMS）of collecting dust from plate under impaction is about 50g. At present electrostatic precipitator’s impaction machine is basically designed by gradual experiences, experiments and revises. With heavy workload, this way is more complex and cost much because of the large structure of ESP. This paper studies the response of Electrostatic Precipitator’s Plate under impaction with finite element method, using dynamic analysis to accomplish the design of impaction device by the analysis of the acceleration distributing on impact, and provides evidences to upgrade ESP.

Abstract: Particleboards bonded with urea formaldehyde (UF) and a combination of UF and methylene diphenyl diisocyanate (MDI) resins were manufactured using wheat straws modified through different steam explosion treatments. The effect of steam explosion treatment, resin system, and mixing ratios of wood and straw materials on the panel properties was investigated. Generally, with steam explosion treatment of straw fibers, panel properties in bending and internal bond (IB) strength increased, thickness swelling (TS) and water absorption (WA) decreased. The bending properties for the panels made from the straws pretreated with 12 h water-soaking were significantly improved at the UF/MDI content level of 5%/1%. The IB strength dramatically increased, while TS and WA decreased with the use of dual resins. With increased weight ratio of wheat straw to wood particles, the bending properties, IB strength, TS and WA deteriorated. Pure wheat straw boards had the lowest properties. Wood particles in substitution for part of straw materials helped improve the panel properties. The results demonstrated that steam explosion modification and/or its combination with UF/MDI dual resin system can be a feasible approach to improve the bonding strength for wheat straw based particleboards.

Abstract: Micro electrical discharge machining (micro-EDM) has some shortcomings such as poor material removal rate (MRR) and high electrode wear ratio (EWR) etc, in order to overcome these demerits, a new piezoelectric self-adaptive micro-EDM, based on inverse piezoelectric effect, was developed in this paper. The structure and working principle of this new technology are different from traditional micro-EDM. Piezoelectric actuator used as the micro driven mechanism and it is simple. This new technology can realize self-elimination in the working process because of its special structure. Working principles and process of the new system were analyzed in this paper. The effect of parameters such as voltage, capacitance, and resistance on MRR, EWR and surface roughness was analyzed. Statistical analyses of the results show that voltage, capacitance significantly influence MRR, EWR and surface roughness. Resistance R1 and R2 has much influence on MRR and relative small effect on EWR and surface roughness.

Abstract: A theoretical analysis was carried out to investigate the characteristics of atmospheric pressure plasma arc injected transverse to a transverse alternating magnetic field and a mathematical model was developed to describe the heat flux density distribution of the plasma arc. The effect of processing parameters, such as flow rate of working gas, arc current, magnetic flux density and the standoff from the nozzle to the workpiece, on the heat flux density distribution of plasma arc were also analyzed. The results show that it is feasible to adjust the heat flux density of the plasma arc by the transverse alternating magnetic field, which can expand the region of plasma arc thermal treatment and flatten the heat flux density upon the workpiece. With the magnetic flux density enhancing, the heat flux density gradient upon the workpiece decreases. Under the same magnetic flux density, the more gas flow rate and arc current, the more heat flux density peak increase. Contrarily, more distance from nozzle outlet to workpiece descends the heat flux density peak.

Abstract: Collaborative optimization (CO) is the most widely used Multidisciplinary design optimization (MDO) method for the design of complex engineering system. But some serious computational difficulties are found in its application. Reasons that cause computational difficulties in original CO were analyzed and a new improved collaborative optimization method (ICO) was presented. The L1 norm was used to improve subsystem consistency constraint and to avoid discontinuities in subsystem object function derivatives. Penalty function was added to system-level object function to convert constrained optimization into unconstrained optimization. A quick-start strategy was used to make the best use of optimal solution of system-level optimization in subsystem-level optimization. Experimental results show that the robustness, reliability and computing efficiency of ICO are higher than CO.

Abstract: In order to study fracture mechanics of high strength steel with the moderate thickness, fracture tests were performed on 10 elliptical notched plates with the thickness of 16mm fabricated from high strength steel Q345. The effect of notch sharpness (the ratio of the length of short axis to that of long axis of elliptic notch, b/a) and notch depth (the ratio of the length of long axis of elliptic notch to the width of plate, a/w) on fracture model of high strength steel was examined. Test results show that the first crack initiates at the notch edge. The fracture ductility is low for the specimens with the sharper notch (a smaller ratio b/a), and the point of crack load lies in hardening phase of load-displacement curve. The fracture ductility is high for the specimens with the obtuse notch (a bigger ratio b/a), and the point of fracture load lies in necking phase of load-displacement curve. There is no qualitative relationship of fracture ductility and the notch depth (a/w). The ultimate strength of notched plates is independent of the notch sharpness (b/a) and notch depth (a/w).

Abstract: An elastic co-film with excellent mechanical properties and adhesiveness, as well as good thermal conductivity, was fabricated based on the composition of a thermal-conductive alumina and ethylene vinyl acetate (EVA) copolymer. Thermal conductivity of the co-films with various particle sizes, amount, surface properties, and so on of alumina were investigated by the laser scattering method. The SEM results showed that the co-film with 16% (volume fractions) of submicron alumina in EVA copolymer had a good interface binding.