NUCLEATION AND GROWTH OF OXIDE NANOPARTICLES PREPARED BY INDUCTION THERMAL PLASMAS

The reactive evaporation method of injected metal powders was investigated for preparing oxide nanoparticles. The method has advantages such as evaporation is enhancement of the injected powder owing to exothermic reaction heat of the metal powder oxidation in induction thermal plasmas. Tangential gas flow injection to the plasma tail flame controls the diameter and the yield of the oxide nanoparticles. The purpose of this research is to investigate the effect of the injection gas flow on the preparation mechanism of oxide nanoparticles in thermal plasmas by experimental work and numerical analysis. An increase in the flow rate of the injection gas leads to an increase in the diameter as well as the yield of the prepared nanoparticles. Numerical analysis for nucleation and growth provides the preparation mechanism of the oxide nanoparticles; however, a more sophisticated model should be developed.     

Effect of dual reinforced ceramic particles on high temperature tribological properties of aluminum composites

The nature and distribution of hard ceramic particles in composite materials influences the properties to greater extent. In the present work, the role of hard ceramic reinforced particles on the tribological behaviour of aluminum metal matrix composites consisting of single (SRP) and dual reinforced particles (DRP) is studied at different temperatures. Zircon sand and silicon carbide particles of size 20–32 μm were used as reinforcement in commercial grade LM13 piston alloy. Composites of dual reinforced particles in aluminum matrix (DRP-AMCs) were developed by mixing 15 wt% reinforced particles by two step stir casting technique. The wear behaviour of DRP-AMCs and SRP-AMCs (single reinforced particles aluminum matrix composite) was investigated using a pin-on-disc method at high temperatures under dry sliding condition. The microstructural examination of developed composites shows globular and finely distributed eutectic silicon in the vicinity of the reinforced particles. Metallographic investigation revealed that the wear zone of the SRP composite consisted of a hardened layer, which is responsible for high wear loss observed in the SRP composite. The results further indicate a transition in the wear mode that occurs after 150 °C for all composites. Study reveals that the dual reinforcement of particles enhances the wear resistance as compared to single reinforced particles if mixed in a definite ratio. A combination of 3% zircon sand and 12% silicon carbide particle reinforced composite exhibits better wear resistance as compared to other combinations at all the temperatures for low and high loads both.     

Comparative Analysis of Energetic Properties of Ti6Al4V Titanium and EN-AW-2017A(PA6) Aluminum Alloy Surface Layers for an Adhesive Bonding Application

The purpose of this article is to present energetic properties of surface Ti6Al4V titanium as well as surface EN-AW-2017A(PA6) aluminum alloy layers. Values of surface free energy after selected mechanical operations and ozonation were compared. In addition, the influence of different values of ozone concentration on surface layer energetic activation was analyzed. Dispersive and polar components of surface free energy were of particular concern. Comparative evaluation of shearing strength of Ti6Al4V titanium and EN-AW-2017A(PA6) aluminum alloy single-lap adhesive bonded joints were presented. Results can be used as pro-ecological methods of titanium and aluminum alloys preparing for applications where adhesive phenomenon is important.     

现场电解制次氯酸钠在污水处理厂出水消毒的应用研究

随着污水厂出水排放标准日益提高,对排水中粪大肠菌群的控制也越来越严格。现场电解制次氯酸钠发生系统是一种较为理想的环境友好型氯消毒技术,能够有效杀灭城镇污水处理厂出水中的粪大肠杆菌。因原水水质不同,次氯酸钠的杀菌效果会有差异。次氯酸钠对原水中的氨氮有一定的去除作用,但是有可能氧化原水中残留的有机氮,从而使得氨氮含量重新升高。现场连续投加试验中,反应池次氯酸钠浓度为1．2mg／L,出水中的粪大肠菌群始终稳定达到GB18918-2002一级A标准的要求,且其他水质指标（如氨氮、COD等）良好。     

EM菌预处理黄姜皂素废水中的应用

本文通过对黄姜废水的水质分析,设计并检验了铁碳微电解-Fenton-絮凝-EM处理方案.主要研究的是EM菌对预处理废水的深度降解,并通过逐一对影响处理效果的的各方面因子等进行了比较分析并讨论了其影响特点.实验结果表明,对于有机黄姜皂素废水,本方案的去除率可以普遍到达98％以上.影响因子分析表明,在温度32℃条件下,EM菌处理预处理废水pH为5左右时,EM投加量为水样的0.7％,处理时间为48h时,处理效果最好.     

原油硫含量测定的意义

硫是石油组成的元素之一,不同石油的含硫量相差很大,由于硫对石油加工影响极大,所以含硫量常作为评价石油的一项重要指标。我国大多以传统的原油硫含量来评价其加工过程所产生的腐蚀程度,而国际上早以引用活性硫来更加合理的评价原油硫腐蚀。介绍了硫分析方法的重要性。此法采用法拉第电解定律的原理,具有操作快速、准确、方便等优点。     

一个应用化学专业综合实验的设计及教学实践

本文以掺铝氧化锌纳米材料的合成、表征及性能研究实验的实际和教学实践为例,探讨通过模拟科研流程的专业实验教学模式培养学生综合应用及创新能力的途径。     

Non‐asbestos Diaphragms in Chlor‐Alkali Electrolysis

For decades in diaphragm electrolysis, asbestos containing diaphragms have been utilized to separate the anode and cathode compartments. Due to the harmful characteristics of asbestos, its world‐wide prohibition in diaphragm manufacturing is expected. The objective of this work was focussed on the development of a diaphragm with sufficient mechanical and chemical stability to substitute the modified asbestos diaphragm currently used. Suitable materials for the manufacture of non‐asbestos diaphragms were identified and a deposition technology was developed which fulfils the requirements of industrial production plants.     

电转气地质储能技术的经济性分析

电转气(power-to-gas)是一项将电能转化为高能量密度可燃气体的化学储能技术,该技术与地质储能相结合,有望满足未来大容量储能需求,并成为未来有效储能技术选择之一.电转气地质储能技术中涉及电离制氢、甲烷化、二氧化碳(CO2)地质储存、人工合成甲烷(CH4)地质储存4个阶段.由于电转气地质储能技术发展处于初步阶段,...     

Characterization of thermochemical properties of Al nanoparticle and NiO nanowire composites

Thermochemical properties and microstructures of the composite of Al nanoparticles and NiO nanowires were characterized. The nanowires were synthesized using a hydrothermal method and were mixed with these nanoparticles by sonication. Electron microscopic images of these composites showed dispersed NiO nanowires decorated with Al nanoparticles. Thermal analysis suggests the influence of NiO mass ratio was insignificant with regard to the onset temperature of the observed thermite reaction, although energy release values changed dramatically with varying NiO ratios. Reaction products from the fuel-rich composites were found to include elemental Al and Ni, Al₂O₃, and AlNi. The production of the AlNi phase, confirmed by an ab initio molecular dynamics simulation, was associated with the formation of some metallic liquid spheres from the thermite reaction.