Advanced Materials Research Vols. 887-888

Abstract: Shenfu coal (SFC) was pulverized and modified with planetary ball mill. Maceral separation of the coal was performed by means of density gradient centrifuge in zinc chloride solution. Blends from low density polyethylene (LDPE) and parent coal powder, iron ions loaded coal powder, or floated maceral fractions were prepared in co-rotation twin-screw extruder. Pyrolysis characteristics were investigated based on differential scanning calorimetry (DSC) measurements, apparent activation energies were calculated according to Kissiger and Ozawa methods. It is found that chemical interaction between SFC and LDPE is attributed to their overlapped pyrolysis temperature regions, leading to instant and rapid propagation and termination of macromolecular chains produced in the co-pyrolysis. Iron ions loaded in the coal can facilitate formation of radicals with acceleration in chemical reaction rates. Thermal degradation of LDPE is rate-determining step in co-pyrolysis of the coal and the polyethylene. Maceral fraction floated in 1.25g·cm^-3 zinc chloride solution is more reactive with polyethylene due to its higher content in aliphatic hydrocarbon and hydrogen, playing a role of excellent hydrogen donor to LDPE in the co-pyrolysis.

Abstract: The expression for the correction factor β, improving the accuracy of elastic modules measurement by sphere indentation is determined. It is shown that to determine β it is necessary determine the exponent in the equation of the loading curve, in additional to the previously determined parameters of the indentation load-displacement diagram. The computed exponent value of the unloading curve is given. It is shown that to analyze β can be used the results of finite element study of the sphere indentation in elastic-plastic hardening material.

Abstract: The expansion property of an infrared CO₂ laser produced air plasma is characterized using a high-speed imaging shadowgraph technique. The shadowgraphs were taken by a time-gated intensified charge-coupled device at various delay times after single pulses induced gas breakdown. We examined five incident laser energy of 180, 240, 345, 420 and 600 mJ induced air breakdown at the pressure of atmospheric and 10⁴ Pa. A shock wave produced by laser induced breakdown was also observed and its speed was measured as a function delay time between the breakdown and the shadow imaging under different air pressure. The experimental results indicated that the radial and axial shock wave front evolutions showed similar behavior, which increased fast with delay time at early stage and slowly at later stage. The propagation speed of the wavefront was about 2 cm/μs at the initial stage of breakdown, and then decreased very quickly. The propagation speed under low air pressure was higher than that of gases under high pressure and the spark sustained less time at lower pressure. The size of laser induced air spark increased with incident laser energy but not simple linear relationships.

Abstract: Phosphate ore was decomposed by using thermogravimetric (TG) and differential scanning calorimetric (DSC). The TG-DSC curves contained different sizes and heating rates. The results showed that phosphate ore had four weight loss stages at the range of 40 ~ 1100°C. With the particle size decreasing, the third weight loss stage became more obvious in TG curves and the endothermic peak became sharper in DSC curve ; the starting and ending temperature of thermal decomposition process moved to higher,the weight loss rate also tended to increase; the activation energy of phosphate ore endothermic decomposition process was calculated by Owaza method in 600~800°C, the average activation energy was 202.80 kJ / mol. It provided a basis for the utilizing of phosphate ore.

Abstract: A new method for material selection in structure design based on the theory of the finite element method was presented. The method made material selection and structure design working at the same time. The mathematical model was established based on the finite element method. Finally, the material selection of an excavator's boom was verified, the results show that the proposed method is effective and feasible.

Abstract: In order to improve high-rise fire-extinguishing efficiency and reduce fire-extinguishing cost, a mathematical model of explosion and dispersion of extinguishing agent was built by using AUTODYN on the basis of isentropic expansion law of detonation outcome and theory of hydrodynamics to simulate the dispensing process of high-rise superfine powder fire-extinguishing agent. Different locations on the high-rise fire-extinguishing bomb were selected to be Gauss points and then were analyzed, all calculating results were contrasted finally. A method used for evaluating fire-extinguishing efficiency of fire-extinguishing bomb was put forward according to the analysis of agent concentration of different moment that it was dispensed, which was referentially meaningful to study the extinguishing efficiency of extinguishing agent.

Abstract: The evaluation theory of resistance affecting gene of metal sheet drawing force is proposed . The evaluated equation on compensate fuzzy control is introduced into resistance affecting gene , the model of affecting gene of metal sheet drawing force on compensate fuzzy control is built . The goal specimen is combined with the special predict results of affecting gene . It is showed that the affecting gene train of correct or error define on compensate fuzzy control . The total error of drawing force of affecting gene on compensate fuzzy control is 0. 06 percent .

Abstract: The point of quantum and immunity algorithm is concluded. A identify model of quantum and immunity algorithm network is constructed. The input and output design of pipe retracting shape parameter is given, and the collection and deal of sample data is also given. Using quantum and immunity algorithm network does the imitate sample of model. The identify result of satisfaction is given. The new field of the pipe retracting shape parameter identify of quantum and immunity algorithm network is opened.

Abstract: Aluminum brass HAL66-6-3-2 is abrasion-resistant alloy with high strength, hardness and wear resistance, corrosion resistance is also well, commonly used in the field of marine and ordnance industry. The quasi static and dynamic mechanical properties were tested through the use of electronic universal testing machine and Split Hopkinson Tension Bar (SHTB). Meanwhile, the material stress-strain curve at different temperatures and different strain rates is also obtained. Based on Johnson-Cook constitutive model, using the method of least squares fitting the experimental data to determine the model parameters, fitting and experimental results agree well.

Abstract: Quality control of construction materials is one of the entire pressure pipeline installation project an important part of quality control. The quality control includes the procurement, acceptance testing, storage, distribution and use during the installation.