Applied Mechanics and Materials Vols. 66-68

Abstract: By designing the different formulations of the composites and adopting optimized technology including extrusion and molding, the effects of the Micro-capsules on the properties of nylon composites are analyzed by the impact property test. The mechanical impact property of the glass fiber reinforced nylon composites is influenced little if the content of the self-healing microcapsules added is less than 3.5%, and the technology of self-healing microcapsules used in the polymer composite gear is feasible.

Abstract: Porous ceramics composite was prepared with mixed powders (Al, TiO₂ and B₂O₃) by SHS (Self-propagating High-temperature Synthesis) method. The effects of the particle size of aluminum power, the additives of SiC and the compacting pressure on the product properties and the pore size, as well as the combustion process in the Al₂O₃-TiB₂ system were researched. The effects of all factors on properties of the product were tested in this paper. The microstructure and mechanical properties (density and compressive resistance strength) were reported. It is learnt from the study that the relation between the open porosity and the pore size does not exist, the former depends on the green density, and the latter depends on the particle size of the aluminum powder. The porous ceramic composite with porosity is ranged from 45% to 68%, pore size is ranged from 1um to 400um, and the compressive strength is about 9.5 MPa. SEM observations of fracture surface suggest that the fracture mode is brittle fracture, and the microstructures of the porous of ceramic composite is very homogenous.

Abstract: This study introduces the transport situation and polices of the highway agency for the M25. Then the current implementation of the Managed Motorway on M25 between junction 5 and junction 7 is reviewed, and some examples are given in this paper. Then a technical state-of-the-art of application is also reviewed. After that, the requirements for integration with complementary systems and polices are presented. Finally, this paper discusses the arguments for and against taking this application forward.

Abstract: As the key components of large-scale hydraulic radial gate, hinge system play an important role in supporting the gate and sustaining loads. They must satisfy the requirements of intensity, rigidity and supporting stability. Due to the complicated working conditions of the gate, it is difficult to calculate stress and strain of the hinge system based on traditional design method. In this paper, taking the radial gate in Silin hydropower station as an example, finite element technology is introduced into the analysis of the hinge system. The approach of this work includes steps of (1) obtaining the maximum load of the hinge system by analyzing and comparing different working conditions of the gate, (2) modeling the hinge system by meshing, loading and boundary constraints, and (3) computing stress and strain of its major components under the most dangerous condition. The results verify design feasibility and structural reliability of the hinge system.

Abstract: The extrusion pretreatment was employed in the aqueous enzyme assisted extraction (EAEP) of oil process. The amount of amino acid was detected during the study. Experimental results indicated that the extrusion pretreatment contributed to the increment of free amino acid amount.

Abstract: The measuring of semantic similarity is the key technique in information retrieval. Based on the common semantic similarity algorithm between concepts, this paper makes use of semantic weighted distance and introduces such factors as node density, concept attribute and concept information content, and presents an improved semantic similarity algorithm to make the measuring semantic similarity more accurate. Through experimental calculation and analysis, the semantic similarity obtained from the improved algorithm can describe more accurately the similar relation between ontology concepts, and correspond to a higher degree with human subjective judgment.

Abstract: In order to predict the size and shape of the laser ablative hole, a 3D finite element model was developed to simulate the Nd:YAG laser ablation of carbon fiber epoxy composite. For given irradiation conditions, good agreement with experimental data relating to hole dimensions. The numerical results and experimental observations indicate that with the irradiation time increasing, the domain under investigation temperature raises rapidly and the further to the spot center, the smaller the temperature raises. After 0.093s the target surface temperature is higher than the critical temperature of composite, so the removal of the material on first composite layer occurs. It also can be observed that heat energy of the laser spread within the material and the isotherm ribbon, as well as crater border, is step-like.

Abstract: The FXLMS algorithm is widely used in active vibration control system. The estimation of secondary path plays very important roles in such a system. This paper presents an experimental investigation of effective secondary path estimation in active vibration control using measured Frequency Response Function (FRF). Principal component analysis (PCA) is pursued to the measured FRF for noise elimination, and then the PCA-compressed FRF data are used for secondary path estimation. The control results indicate that the proposed method has good control performance.

Abstract: Cored wires and arc spraying technique were used to produce Zn-Al-Mg-RE alloy coatings on low carbon steel substrates. The effect of RE (where RE is Rare Earth) on the microstructure and electrochemical corrosion behavior of coatings was investigated comparing with Zn-Al-Mg coatings. With addition of RE, the Zn-Al-Mg-RE coating has denser microstructure and fewer porosity. But RE has no discernible effect on the adhesion strength between coating and substrate. The Zn-Al-Mg-RE coating has superior corrosion resistance compared to Zn-Al-Mg coating due to the formation of more compact and uniform corrosion products. The role of the RE elements appears to be associated with the self-sealing process and the refinement of the coating microstructure.

Abstract: The Mg-6Zn-6Al-0.5Mn-0.6Si-0.1Ca alloy has been produced in a steel crucible in an electric resistance furnace protectived by CO₂+0.5%SF₆. The microstructure of the as-cast alloy consisted of matrix–α(Mg) supersaturated solid solution, τ(Mg₃₂(Al,Zn)₄₉) ternary-phase and a small polygonal type Mg₂Si phase in matrix. The τ(Mg₃₂(Al,Zn)₄₉) ternary-phase dispersion distribution in grain boundaries. After solution-treated, the amount of quasi-continuous net-shape ternary-phases reduce and small part of ternary-phases dissolve to the matrix which lead to the distribution on the matrix more uniform than as-casting condition in the alloy. The results of tensile, microhardness, impact toughness and corrosion property show that the alloy has better compressive properties.