Advanced Materials Research Vols. 706-708

Abstract: This experiment research the dirt adhere on heat exchanger in the sewage-source heat pump system，which contained moisture content test, ash content test, a digital microscope observation, scanning electron microscope observation, X-ray diffractometer analysis. The experimental results show that the heat exchange surface dirt moisture content is between 90.10% ~ 95.80%. The microflora of dirt is mainly staphylococcus and bacillus, and preferentially attach on rough position. Dirt main inorganic crystal component is SiO2 and Mg (SiO3).

Abstract: In order to obtain high-quality injection head, cold extrusion forming is adopted. Based on the study of forming technology for the injection head, reasonable process flow, cold extrusion pre-treatment process and boundary conditions are designed. Two finite element models in forward extrusion and backward extrusion forming ways are established. Taking DEFORM as the platform, the numerical simulation of forming process is carried out. Through simulation, the distribution of strain field, stress field and velocity field in the process of cold extrusion forming is preliminarily forecast, the merits and defects of two kinds of forming processes and the force state of mold are compared , the optimal forming scheme is determined.

Abstract: Press forging forming is a combined extrusion process for forming round-fin on heat sink on thick metal sheets. A series of simulations on the round-fin forming using the program DEFORM were carried out. The blank thickness and friction coefficient on the formation of round-fin were studied. The results show that the blank thickness is very good for the round-fin formation, and the thicker the blank is, the better the round-fin can be formed; and also when both the punch-blank interface and the die-blank interface have the same value of friction factor, the larger value of friction factor is in favor of round-fin forming, the further investigation reveals that the friction at the punch-blank interface has more significant effect on preventing the initiation of flow-through compared with the friction at the die-blank interface, which implies that the punch-blank interface has more significant effect on the material flow in the formation of round-fin.

Abstract: In order to improve the performance of the piston head on the existing conditions, and the warm extrusion forming technology was put forward based on the internal combustion engine piston head traditional production process. The warm extrusion process scheme and finite element boundary conditions was designed reasonable based on research the piston head forming process, the thermal-mechanical coupling model was established. The numerical simulation of the warm extrusion forming was carried out on the DEFORM software platform. The distributions of warm extrusion forming process strain field, stress field and temperature field were forecasted through the theoretical calculation and simulation. And the production equipment tonnage and die structure form were determined preliminarily. The possible problems of forming process were discussed, and the countermeasures were also put forward, provide the reliable reference for internal combustion engine piston head forming process improvement.

Abstract: Palygorskite had large applications in chemical, environmental protection, medicine processes and so on. However, since the mineral limitations of natural palygorskite, both improving its quality and meeting the need of industry, palygorskite usually needs to be activated before using it. The influences of activation during the drying process were studied, as well as the drying kinetics of the non-activated of palygorskite. The results showed that the drying rate of palygorskite increased at first，and then came to a constant value, and kept that value for some time. After that, drying rate decreased with time going. Compared with drying curves of the non activated palygorskite, the samples made some changes after activation. The drying process of non activated palygorskite could be described as the equation of MR=exp(-ktⁿ).The diffusion activation energy (E) of non activated palygorskite was equal to 17.14kJ.mol^-1, former factors of Arrhenius was equal to 4.19×10^-5 m².s^-1.

Abstract: Powder high speed compaction mechanism is still a controversial issue.In order to study the densification mechanism of powder in the high speed compaction process,the article aims to study the powder densification mechanism by using the discrete density volleyball accumulation model that MSC.MARC to Ti6A14V and to describe the microscopic deformation and temperature changes of powder with Johnson-cook model. By analyzing the speed and temperature changes of particles in different position node,we found that powder particles start to deform a lot within microsecond and fill the holes and gaps of the powder in the flow,so that the air in the particles will form high-pressure and high-energy in a relatively adiabatic environment and make the temperature high and partial melting of the particle surface. It proves that the consolidation is the major mechanism of particles’large deformation,heat and soften hot-melt process in a short time.

Abstract: Objective: to explore the wastewater quality conditions which made sludge bulk easily, and the sludge properties when sludge bulking happened. Methods: wastewater was treated by SBR process, and sludge volume index (SVI) in different wastewater quality conditions was determined by controlling water temperature, dissolved oxygen (DO) and pH value. Conclusion: under low temperature conditions, effect of DO concentration on SVI was great; and the lower DO concentration, the more serious sludge bulking. But pH value had less effect on SVI, and only mild filamentous sludge bulking happened on activated sludge at low pH value (pH=6.0-6.5). Moreover, SVI tended to be steady at late period of operation, and the average was 203 mL/g.

Abstract: Abstract: The thesis is aimed to study the characteristics nonlinear seismic response of the isolated continuous girder bridges with LRB. Inorder to achieve the aim, force- deformation properties of the LRB is considered as bilinear first, the bouc-wen model is adopted to imitate the force nonlinear deformation behavior of LRB, and by using Finite element method, the motion equation of the Isolation system of continuous girder bridge is established, then some shaking table tests towards the model of isolated continuous girder bridges with LRB is done. On this basis of it, by comparing the experimental results and calculation results, such as the acceleration and displacement of deck, vertical force of bearing, and the relationship between the Isolation layer displacement and the Level force displacement of the Bearing, we can see that the difference between the analytical results and the experimental results are very small. The results show that the calculation method can analyze Nonlinear Seismic Response of isolated continuous girder bridges with LRB efficiently. But when the vertical earthquake component is larger ,whether the results of the Vertical tension are produced or not, designing the Rubber bearings should be considered.

Abstract: Antimony distributes widely in the environment. And antimony pollution in the water environment is becoming serious. How to detect the content of the antimony correctly and effectively is very important. Graphite furnace atomic absorption method is simple, but low sensitivity; hydride generation atomic fluorescence spectrometry, low cost, good reproducibility, but is harmful to the introduction of substances; inductively coupled plasma mass spectrometry for simultaneous multi-element analysis, high sensitivity, but the operation is cumbersome; inductively coupled plasma spectrometry has low detection limit, high accuracy, but the equipment is expensive, and cost of analysis is high.

Abstract: Collect geological and hydrogeological data of Yili NO.1 coal mine and analyze Hydrogeological Characteristics of sandstone aquifers in the roof of No5 coal seams; predict the water abundance and classify sandstone aquifers’ water abundance with considering the sandstone’s thickness, content and lithology structure index, and provide the basis for controlling the sandstone water of NO.5 coal seam’s roof.