Advanced Materials Research Vols. 228-229

Abstract: Since the aluminum alloy quenching is a complicated and a prompt heat-pressure coupling processing, traditional experimental tests and empirical judgments cannot explain and predict the physical and the force behavior completely during the quenching process. Dynamic simulation of the quenching process is conducted using the finite analysis method. Development laws of the stress and the strain field of the surface layer and core of the alloy during the quenching process are described based on the verification of the simulation. States and process history of the stress and the strain in each phase during the quench are obtained, which provides ponderable data and theoretical value for a fully understanding of the aluminum alloy quenching.

Abstract: Ammonium polyphosphate (APP) was prepared by process of diammonium hydrogen phosphate at different ammonia atmosphere. XRD techniques were used to characterize the crystalline form of this product. Results showed that ammonium had significant effect on the crystalline form of prepared ammonium polyphosphate. The results were informative for controllable preparation ammonium polyphosphate in industrial production.

Abstract: Ammonium polyphosphate (APP) is an effective intumescent flame retardant, it has different crystalline forms and therefore, different application. The crystalline transformation from form II to form V was measured. The results were informative for controllable preparation ammonium polyphosphate in industrial production.

Abstract: Faced with the serious pollution problems of blasting smoke after blasting with the ventilation method based on pressure, using single transformation ejector auxiliary ventilation was raised in the paper, namely ventilation based on pressure was put into use when it was normal, but ejector auxiliary ventilation was used after blasting. The simulation of the condition by fluid analysis software when ejector auxiliary ventilation and ventilation method based on pressure were conducted, and a inclusion was presented that ejector auxiliary ventilation had a good effect on exhausting smoke for the long tunnel with small section, and it has an advantage of shortening exhausting smoke time and less pollution to the roadway, Ventilation can be divided into two phases, when the ejector inlet is submerged in the smoke, smoke is suck out mainly through ventiduct. when the ejector inlet is exposed to fresh air flow, the ejetor assist smoke get out through ventiduct.

Abstract: The injection molding of magnetic powder could cost-effectively mass-produce net shape magnets. In order to prepare the injection molding bonded NdFeB permanent magnet material with better combined properties, the effect of binder on the magnetic property, mechanical property and fluidity of injection molding magnets and its mechanism microcosmically were investigated. The effect of additives such as silicone coupling agent, compound lubricants and antioxidant on the properties of injection molding magnets are discussed. The injection molding bonded magnets were prepared by using the MQP-B rapidly quenching NdFeB magnetic powder and polyamide 12. The magnetic properties are :Br=0.539T, Hcb=345.37kA/m, Hci=681.02kA/m, and (BH)max=47.37kJ/m3.

Abstract: As the evolution of automobile industry, the application of cars has been gradually extensive. Nowadays, automobiles have been an essential part of modern society .The development of car equipments has also been accelerated by the growing popularity of the automobiles. Meanwhile, if these equipments are not regulated rationally, they also rouse extra consumption of power stored in car batteries. GPS system, as an example, causes unnecessary consumption while the automobiles are at rest. As the power loss of automobiles may cause series of dangers, such situation should be avoided. The article provides a feasible way to make an intelligent control on power supply system of automobiles through AVR single chip programming. Thus helps regulate the usage of the car batteries. From this, automobile securities can be enhanced.

Abstract: For the current lack of convenient, reliable and safe lifting of the fire escape equipment, design a device along the rope, using functions with self-locking worm gear structure. Then assess the strength of the contact state and reliability of the structure, use ANSYS to analysis the contact stress and dynamic characteristics. Finally, improve the winch device design to increase the safety factor. The check calculation and experiments showed that the device can be safely hoisting the target.

Abstract: In the present work, The Chen and Fan (CF) model [1] of semisolid metal slurries (SSMS) is improved by modifying the expression of the packing parameter, of the solid particles and then the modified CF (MCF) model is obtained. Subsequently, the MCF model is applied to the Al-6.5wt%Si alloy to investigate its rheological behavior at steady state. The factors which affect the steady state behavior have been studied. It has been shown that the steady state viscosity and the average agglomerate size increase with increasing the solid volume fraction and decreasing the shear rate. The prediction of the model is in good agreement with the experimental results in the literatures qualitatively. The importance of the effective solid volume fraction is shown by explaining the strong coupling between the viscosity and the microstructure. The external flow conditions such as shear rate etc change the agglomeration degree, that is, the effective solid volume fraction and then the viscosity

Abstract: In this paper the author tries to establish the corresponding air-structure coupling dynamic characteristic equation of the sounding board system, in line with the coupling fluid flow as well as the prestress conditions, then this dynamic characteristic equation is simplified.The coupling modal of the whole sounding board system is calculated by using the software of ansys, and the data of gunpowder explosion pressure pulsation is obtained from the calculation in autodyn, then the frequency and modal of the sounding board system were further analyzed in the software of ansys. The results show that there are some significant changes in the frequency and modal of the sounding board system under the condition of prestress as well as the air-structure coupling of gunpowder pulsation fluid flow.

Abstract: For finding influence of the surface wettability on dropwise condensation heat transfer, a model for dropwise condensation heat transfer has been established based on the drop size distributions and the heat transfer rate through a single drop with considering influence of contact angle to heat transfer. It has been shown based on the proposed model that up to a drop radius of 5μm, the rate of decrease in the drop population density is not as steep as the rate for a drop radius greater than 10μm, because coalescence between drops starts taking place. Varying the contact angle changes the drop distribution; higher the contact angle, lower the departing droplet size and large number density of small droplets. Heat flux first increases and then decreases with increasing contact angle under the temperature difference condition.