Vaporization coefficients of SiO2 and MgO

The vaporization coefficients are measured for both SiO₂ (cristobalite) and the (100) face of MgO. These oxides vaporize congruently and are studied with free surface (Langmuir) vaporization using a vacuum thermogravimetric apparatus. The measured fluxes are compared to the calculated equilibrium fluxes to determine vaporization coefficients. Post-vaporization microstructures are also examined and discussed in regard to the vaporization process.     

Oscillatory vaporization and acoustic response of droplet at high pressure

Open-loop dynamic responses of vaporizing droplet to high-frequency pressure waves are theoretically-numerically investigated. Conservation equations for liquid and gas phases are solved separately for spherically symmetric vaporization and transports, and flow parameters are matched at liquid–vapor interfacial boundary. The pressure-coupled response of the droplet vaporization is commanded by the coupling between the acoustic and thermal processes occurring in an immediate vicinity of the interfacial boundary. The vaporization response strongly depends on the ambient pressure, and the acoustic instabilities are expected at higher pressures and lower frequencies.     

Effect of Annealing Atmosphere on the Mechanical Property of Free-cutting Phosphor Bronze Alloy

The present work is focused on the influence of annealing atmosphere on the microstructure and mechanical property of free-cutting phosphor bronze alloy.The annealing of the alloy was conducted in the three kinds of annealing atmosphere such as air,vacuum and nitrogen.After annealing,a discernable difference in recystallized grain size and lead particle size was not appeared with different annealing atmosphere.The tensile strength of the alloy annealed in air or nitrogen atmosphere was higher than that of those annealed in vacuum atmosphere.In thecase of the alloy annealed in vacuum atmosphere,the mechanical strength was reduced by vaporization of zinc.In the case of annealing in nitrogen and in air atmosphere,the sweating of lead was occurred.However,the inverse segregation of lead was suppressed by copper oxide layer on the surface annealed in air.This copper oxide layer leads to a decrease of the yield during fabrication process. Therefore,annealing of the alloy in nitrogen atmosphere is favorable in terms of the mechanical strength and yield.     

Heavy metal vaporization and abatement during thermal treatment of modified wastes

This study examines the vaporization percentage and partitioning of heavy metals Cd, Pb and Zn during thermal treatment of wastes with added PVC, heavy metals or phosphate, and the efficiency of sorbents for removal of these metallic compounds in flue gas of an industrial solid waste incinerator. Firstly, vaporization experiments were carried out to determine the behavior of heavy metals during combustion under various conditions (type of waste, temperature, presence of chloride or phosphate ...). The experimental results show relatively high vaporization percentage of metallic compounds within fly ash and limestone matrix while heavy metals within sediments treated with phosphoric acid are less volatile. Vaporization of metals increases with increasing temperature and with chloride addition. The thermal behavior of the selected heavy metals and their removal by sorbents (sodium bicarbonate, activated carbon) was also studied in an industrial solid waste incinerator. These pilot scale experiments confirm that heavy metals are concentrated in fly ashes and cyclone residues, thus effectively controlling their release to the atmosphere.     

氧化铝陶瓷干压坯体的烧结制度探讨

针对干压坯体烧结中常见的瓷件开裂、阴斑、机械性能下降等问题结合实践进行分析,指出干压坯体不同于热压铸坯体的烧结特点,并给出了具体的烧结曲线建议。     

CALCULATION OF THE VAPORIZATION ENTHALPY OF NONPOLAR FLUIDS AT THE STANDARD TEMPERATURE

Different analytical models were used to calculate the enthalpy of vaporization of nonpolar fluids at the standard temperature of 298.15 K. The models considered were some general classical expressions, three group contribution models that allow the property to be calculated at any temperature, another group contribution model specifically designed for calculations at the standard temperature, and finally a molecular model proposed by our research group. The results for 42 nonpolar fluids are compared with the value obtained in the correlation proposed in the DIPPR project.     

Comparison of oxidation behavior of Ni–20Cr alloy and Ni-base self-fluxing alloy during air plasma spraying

Oxidation behavior of Ni–20Cr alloy and Ni-base self-fluxing (NiCrSiBC) alloy in atmospheric plasma spraying was studied experimentally. The in-flight particles were collected by quenching into liquid nitrogen. The oxygen contents in the collected particles and the coatings deposited on a substrate were analyzed by the inert gas fusion method. The oxide distribution, morphology and phase composition were analyzed using SEM, EDX, XRD, and AES. The results clearly show that the oxygen content in the NiCrSiBC coating was remarkably lower than that in the Ni20Cr coating by a factor of over 10. The formation of Cr₂O₃ and its vaporization primarily occurred during the flight of Ni20Cr particles, which dominated the oxidation in the coating. In contrast, little oxygen pickup occurred during flight for the NiCrSiBC alloy particles and a thin surface layer of 5 nm with rich in oxygen was found on the surface of NiCrSiBC splats. The mechanism of protecting NiCrSiBC alloy particles from oxidation is preferential oxidation of C, Si and B and simultaneous vaporization of the formed oxides.     

低温液体汽化充装系统事故原因及预防措施

分析了目前低温液体充装系统发生事故的原因 ,指出根据汽化器出口温度、压力报警与泵电机联锁设计及泵的排量、汽化器、汽化量、充瓶数之间的关系设计 ,是保证充装系统安全的有效措施。     

纯物质汽化热的预测

在纯物质常沸点汽化热的剩余函数预测法的基础上,结合并改进W-S方程,推导出预测纯物质在任一温度下的汽化热的新方程。由最基本的物性数据T_b,T_c,P_c,预测245种各类物质7574个温度点的汽化热,与实验值相比较的总绝对平均误差为1.77％,优于原剩余函数法。     

Use of triboelectric probes for on-line monitoring of liquid concentration in wet gas-solid fluidized beds

The objective of this study was to validate the effectiveness of a novel method employing triboelectric probes for accurate on-line solid moisture measurements in fluidized beds. Liquid injections were conducted in a fluid bed of glass beads and the resulting solid moisture was monitored during the whole drying stage by acquiring triboelectric signals generated from several locations inside the bed. For various superficial gas velocities and amounts of injected liquid, the bed drying end point and the fraction of sprayed liquid involved in the formation of slow-vaporizing stable agglomerates were estimated performing fast signal analysis by means of the W statistic.