Applied Mechanics and Materials Vols. 26-28

Abstract: With the increasing demand of building metro construction, couple with its complexity, there is a great need on an integrated system to provide all the stakeholders a convenience way to exchange information effectively and efficiently. An integrated system based on 6D is proposed by this article. The core technology of the system including BIM theory and methods of associating 3D graphics models with progress, investment and safety information are discussed. By using the integrated system, it helps the project decision makers in planning, coordination and control of management to improve project management efficiency. Also, a case study is provided which is used in Wuhan metro construction and achieves good results.

Abstract: Carbon foams were prepared by a polymer sponge replication method and their microwave absorbing properties were investigated in this paper. It was found that the electric conductivity of carbon foams increases quickly with the improvement of carbonization temperatures. Moreover, the electric conductivity of carbon foams strongly affects their microwave absorbing performances. As the electric conductivity increases from 0.02 S/m to 1.03 S/m, the dominant electromagnetic behavior of carbon foams changes from transmission to reflection with regard to the incident electromagnetic wave. The best microwave absorbing performance was achieved for the carbon foam with an electric conductivity of 0.46S/m when other parameters are fixed at constants, and absorbing values for the carbon foam exceeds 7dB almost in the whole measured frequency range of 4-15GHz, while the frequencies range for absorbing values exceeding 8dB are about 7 GHz, demonstrating a characteristic of broad absorbing bandwidth. It is to be noted that the absorbing characteristic for the carbon foam with an electric conductivity of 0.46S/m is obtained without any impedance match design, which indicates that carbon foams have the possibility to be applied as broad absorbing bandwidth RAMs.

Abstract: Extension rule is a new method for computing the number of models for SAT formulae. In this paper, we investigate the use of the extension rule in solving #QBF, i.e., computing the number of Q1x1…Qn xn which makes the Quantified Boolean Formulas (QBF) Q1x1…Qn xnF evaluate to true. We present a #QBF algorithm based on the extension rule, namely QBFMC, which also integrates the unit propagation and the component analysis together. These excellent technologies improve the efficiency of solving #QBF problems efficiently.

Abstract: To reduce the cost of food inspection, we built a minimum cost sampling inspection model on the basis of simple random sampling, and ensured that the reliability of sampling inspection lived up to the required reliability at the same time. In this model, according to the relationship between inspected qualified rate and standard qualified rate, we adjusted the sample size through relaxing and tightening the inspection. The result shows that this plan can greatly reduce the inspect cost. Besides, the model is flexible, and it can formulate different sampling inspection plans according to the required reliability.

Abstract: The microstructure evolution taking place in Fe-32%Ni alloy during multi-axial forging was investigated by electron backscattered diffraction (EBSD). The samples were compressed with loading direction changed through 90º from pass to pass at temperature of 650°C and a strain rate of 10-1/s. The results show the microstructure evolution is characterized by continuous grain subdivision process, i.e. the multi-axial forging promotes the development of deformation bands in various direction followed by their frequent intersection in grain interiors with changing of strain path, which results in continuous fragmentation of coarse grains into subgrains. Concurrently the misorientations of subgrain boundaries rise gradually with repetitive deformation followed by their progressive transformation into high angle boundaries. The ultra-fine grains are concluded to evolve by continuous dynamic recrystallization (CDRX).

Abstract: In order to improve quality and efficiency of the overall five-axis milling for arbitrary surface impellers. In rough milling, the arbitrary surface was replaced by fitted ruled surface, the flank milling was a good method to replace the point milling. In semi-finish milling, the primal surface was replaced by piecewise ruled surfaces, using step flank milling to gain the satisfaction in model’s nicety and machining efficiency. Then , algorithm of the paper is proved to be viable by Model building, NC programming and machining.

Abstract: In order to find a more effective method for real estate investment evaluation, the grey AHP is applied and hierarchical assessment system is presented. First, the grey-relevant method is employed to evaluate the profit of the investment. During quantifying the qualitative indexes, set-valued statistic analysis is introduced, which reduces the uncertainty of the real estate investment assessment. A case shows that the method is feasible and valid. This study has significance in theory and practice for the real estate investment management.

Abstract: In order to find a more effective method of solving the problem of subjectivity and difficulty to deal with the high-dimension data, an improved Projection Pursuit (PP) based on Particle Swarm Optimization (PSO) was introduced. The PSO algorithm was employed to optimize the function of the projected indexes in the PP. Application results show the efficiency of the modification. This study has significance in theory and practice for the related research.

Abstract: In order to find an effective method for solving the NP problem-dimensional cutting stock problem, the improved ACO based on entropy was introduced．After introducing the basic knowledge of the improved ACO, the dimensional cutting-stock problem’s mathematical model was set up．And the improved ACO was employed to optimize the problem．Computed results indicate that the ant colony algorithm can approach the theoretical optimal solution，and its astringency is good．This study provides a new approach for the optimization of the NP hard problems.

Abstract: Photocatalytic activities of TiO2-HZSM-5 composite photocatalysts prepared by solid-state dispersion method were investigated. TiO2 particles were well distributed on the surface of HZSM-5. Methyl orange removal rates increased with decreasing TiO2:HZSM-5 ratio from 10:1 to 1:50 in TiO2-HZSM-5 composites. Adsorption of methyl orange increased constantly with increasing amount of HZSM-5. Photocatalytic degradation activity was also noticeably enhanced up to 56% when using TiO2-HZSM-5 composite, resulting in 13% more removal compared with using pure TiO2. Composite photocatalysts calcinated at temperatures from 400 oC to 600 oC exhibited enhanced methyl orange removal abilities, and the optimum calcination temperature was 450 oC. After 70 min of irradiation, methyl orange removal rates were 99.1% and 86.5% when TiO2 concentrations of TiO2-HZSM-5 composite were 40 mg/l and 20 mg/l, respectively.