Advanced Materials Research Vols. 268-270

Abstract: Temperature plot is crucially important for numerical simulation of high waxy crude pipeline because of its non-Newtonian behavior at low temperature. As the fluid temperature drops below than the wax appearance temperature, the viscosity of the crude increases dramatically. Thus the needed pressure has a possibility to reach the maximum allowable pressure and cause a potential risk for the pipeline itself. To avoid this, numerical simulation of the temperature plot along the pipeline is necessary in order to obtain accurate information. However, as the temperature governing equation is a non-linear equation and the soil temperature field is also being involved. It is required to solve the surrounded soil temperature field. In the paper, the governing equation for one dimensional crude pipeline and the new moisture-heat equation for the soil (porous medium) are presented and the iteration algorithm to solve this coupled equation is given. With the algorithm and the coupled heat-moisture equations, the numerical results are obtained and have a very precise coincidence with the experimental results. Then a reliability based method is used to evaluate the flow safety of one pipeline in China. With the presented model and obtained results, the flow safety evaluation results show that the safety of the crude pipeline is assured in the test cases.

Abstract: Through full factor analysis of the stiffness of the components which have potential influence on vehicle front impacts, through sensitivity analysis of vehicle front impacts using Linear Regression Method, the stiffness significantly affected the impacts are chosen as the optimization variables. The vehicle intrusion and the deceleration waveform of B pillar are weighted as the optimization objective. The Latin Hypercube Sampling Method is used to do sampling; a response surface of the calculation results is established using Kriging Method; the optimization is done using Method of Feasible Direction, finally the most optimal car body stiffness is determined, and which can provide the basis for frontal crash safety design of the electric vehicle.

Abstract: This paper presents a metric-based semi-supervised fuzzy c-means algorithm called MSFCM. Through using side information and unlabeled data together, MSFCM can be applied to both clustering and classification tasks. The resulting algorithm has the following advantages compared with semi-supervised clustering: firstly, membership degree as side information is used to guide the clustering of the data; secondly, through the metric learned, clustering accuracy can be greatly improved. Experimental results on a collection of real-world data sets demonstrated the effectiveness of the proposed algorithm.

Abstract: Simplification of the detail reaction mechanism is critical to the numerical simulation of BFG (Blast Furnace Gas) combustion. The software CHEMKIN was used for solving a one-dimensional mathematical model of steady-state premixing combustion. By analyzing the effects of BFG’s basic species on the burning rate, the simplified reaction mechanism was obtained. Compared the results of simplified mechanism with that of detail mechanism, the consumed time of the former was less than 1 second but that of the latter was about 18 seconds. The differences between the molar fractions of BFG species which were computed by the two mechanisms were less than 0.4%. Therefore the reliability of the simplified reaction mechanism is verified.

Abstract: This paper studied at recycling and using of metallic tailings on the refractory used in aluminum-smelting furnace. The masonry arts and crafts of combustion chamber wall are introduced. The software FLUENT is used for simulating the temperature distribution of combustion chamber wall, which is used for software ANSYS as the temperature condition to simulation of heat stress of combustion chamber wall in bad operating condition. Contrast the simulating results of new type material with the traditional refractory one, the better performance of the refractory products with new type material is verified. The results can be an academic reference for synthetically application of metallic tailings. The extend application of the technology of metallic tailings on aluminum-smelting furnace will give a great impulse to the energy saving and environmental protection.

Abstract: The melting and freezing with two different cooling rates of Ag_N (N= 140, 360, 532, 784, and 952) nanoclusters are simulated by using molecular dynamics technique with the frame work of embedded atom method. The potential energy as a function of temperature is obtained and the structural details are analyzed. The results reveal that the melting and freezing temperature increases almost linearly with the atom number of the clusters except for Ag₃₆₀. All the silver nanoclusters have negative heat capacity around the phase transition temperature, and the clusters with slow cooling rate have icosahedral structure at 300 K.

Abstract: High temperature in fire have serious influences on the structural behavior of reinforced concrete structure, and causes damage in structure, even leads to overall collapse. By thermal and structural analysis using finite element method, the whole-course behavior of a reinforced concrete bridge in fire is simulated, and the transient temperature field, deformation and stress is discussed. These information supply the basis for fire resistance of concrete bridge design.

Abstract: Magnesium borate hydroxide (MgBO₂(OH) ) were synthesized using magnesium nitrate hexahydrate(MgNO₃.6H₂O) and borax decahydrate(Na₂B₄O₇.10H₂O) by hydrothermal route. Effect of reaction temperature , reaction time and water's volume on the composition , structure , and crystal morphology of the products were investigated, and the products were characterized by XRD and SEM. The results indicated that all of the products were szaibelyite with the reaction condition investigated, and crystal morphology could be tailored via varying the reaction condition.

Abstract: Using the method of the parameter study, some important dimensions of the cylinder head of an internal-combustion engine are analyzed. Under the mechanical load, the variational rules of the Von Mises maximum stress on cylinder head are obtained, which are influenced by the thickness of the floor plate, head plate, jobbing sheet, standing partition board, and side plate of inlet port and exhaust port. A hypothesis is verified that there is an ideal matching point among those above-mentioned main parameters. The quantificational proportion relations, between these key structural parameters and Von-Mises maximum stress of cylinder head, can provide a good help for the cylinder head’s structural design.

Abstract: According to the analysis of acoustic signals and vibration signals measurement, an investigation of the noise source identification in a diesel is presented, and the noise level of the diesel is comprehended. With the sound Intensity method, the major sources of the exterior radiation noise of the engine are surveyed. The research provides the reliable basis for the engineering practice to reduce the vehicle noise level.