基于QPSO算法优化跳汰机排料系统的分数阶PID控制

针对传统PID控制在复杂跳汰机排料系统中控制精度不高、响应速度慢、参数调整不够精确等问题,提出了一种基于QPSO算法优化的分数阶PI~λD~μ控制器(QPSO-FOPID).该控制器利用分数阶微积分理论,将传统PID控制由整数阶次推广到复数阶次,并增加了两个参数的自由度.同时利用量子粒子群算法对分数阶PI~λD~μ控制器参数进行寻优,解决参数调整不精确的问题.以某矿井跳汰机排料系统为例,建立跳汰机排料系统控制的Simulink仿真模型.仿真结果表明,该方法不仅能够实现分数阶PI~λD~μ控制参数的在线优化,收敛速度快,具有较强的鲁棒性,还具有良好的动、静态性能,无超调现象,控制精度高.     

Effect of melt sonocrystallization on pharmacotechnical properties of paracetamol,indomethacin and mefenamic acid characterized by dynamic laser scattering and its impact on solubility

The purpose of the research was to employ a novel particle engineering technique-melt sonocrystallization (MSC) for some nonsteroidal anti-inflammatory drugs for development of more soluble forms of the drugs without the use of excipients. The original forms of Paracetamol (OFPCM), Indomethacin (OFIMC) and Mefenamic acid (OFMA) were subjected to MSC to improve physicochemical properties. MSC forms of PCM, IMC and MA were subjected to dynamic laser scattering for particle size analysis to quantize mean particle size, specific surface area, interquartile coefficient of skewness, kurtosis and span. Rheological and solubility analysis, X-ray powder diffraction and scanning electron microscopy were conducted for validating the effect of MSC on powder particles. On melt sonocrystallized form of drug powders exhibited improved micromeritic properties, the mean particle size was reduced while the specific surface area increased effectively. Frequency distribution curves showed reduction in asymmetry and skewness that was confirmed by interquartile coefficient of skewness values. Equilibrium solubility of MSC form of PCM, IMC and MA was higher than the original forms. Similarly the intrinsic dissolution rate was approximately 1.5 times higher in comparison to original form of drugs. X-ray powder diffraction shows decreased relative intensities of peaks of MSC forms due to reduction in the crystallinity that was confirmed by visualization of MSC particles by scanning electron microscopy. Conclusively, MSC is a promising cost-effective technique that may afford powder with improved flow and formulative properties as well as improved solubility and dissolution.     

Flame spray drying: Droplet and particle flow dynamics

ABSTRACT

The work presents the fundamental research of dispersed phase flow during flame spray drying. Particle dynamics analysis and laser Doppler anemometry technique were applied to determine particle size distribution and particle velocity distribution. Results of the study showed that stable combustion and longer length of the flame were observed for coarse spray (large droplets, low atomization pressure, small spraying angle, and low concentration of droplets in spray). Particle residence time in the combustion zone is the main factor affecting the increase in particle diameters due to puffing. Complex flow dynamics of dispersed phase observed at the outward regions of the flame in recirculation zones results in the formation of particle agglomerates.     

Extraction of aluminium as aluminium sulphate from thermal power plant fly ashes

Valuable metal extraction technology from thermal power plant fly ash is limited. In the present study, aluminium is extracted from fly ash as highly pure aluminium sulphate (>99.0%) by leaching with sulphuric acid, followed by pre-concentration and successive crystallization. Two types of fly ashes from different sources, i.e., Talcher Thermal Power Station (TTPS) and Vedanta Aluminium Company Limited (VAL) were chosen for comparative study on the extraction of aluminium as aluminium sulphate. The product is characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Purity of aluminium sulphate was also investigated by inductively coupled plasma–optical emission spectrometry (ICP–OES). The extraction efficiency of aluminium depends on the varied solid-to-liquid ratio (fly ash : 18 mol/L H₂SO₄, g/mL) and particle size of fly ashes. Physico-chemical analysis indicates that the obtained product is Al₂(SO₄)₃·18H₂O, having low iron content (0.08%).     

大气颗粒物及其组成研究进展(上)

颗粒物是空气中最重要的污染物之一,由于颗粒物表面的吸附作用,其组分非常复杂,其中含有多种有毒有害的化学成分,对大气环境造成不良影响,并危及人体健康。借助大气颗粒物及其组成成分的测定,通过污染源解析分析其来源及影响因素,控制大气颗粒物的排放,对于保证大气环境质量、改善人们的生存环境具有重大意义。本文对此进行综述。着重介绍大气颗粒物及其组成成分、源解析及测量技术的最新进展。     

Modeling of compressive strength of cemented sandy soil

This paper attempted to show the application of particle swarm optimization in the prediction of the compressive strength of cement sandy soil from the curing period, porosity of sample and percentage of cement. The results of the study show that the unconfined compressive strength of the cement stabilized sandy soil increases with an increasing cement content curing time period. Moreover the compressive strength decreases with an increasing porosity. The compressive strength improvement due to cement treatment has a larger increase in samples with less porosity. In addition, particle swarm optimization algorithm is and accurate technique in estimation of compressive strength of cement stabilized sandy soil. In order to compare of existing correlations, a total number of 100 unconfined compressive tests and 15 scanning electron microscope tests have been conducted on cemented Babolsar sand. It can be concluded that compared to existing correlations models, particle swarm optimization algorithm models give more reliable prediction about compressive strength of cement satblized sandy soil. Moreover, the sensitivity analysis of the polynomial model shows that cement content and porosity have significant impact on predicting unconfined compressive strength.     

硼颗粒的包覆机理及工艺研究进展

阐述了不同包覆材料对硼颗粒的包覆机理,从5个方面总结了硼颗粒包覆材料的选取原则,包括:去除硼颗粒表面氧化膜、提高燃烧温度、降低硼的点火温度、提高表面相容性、催化硼颗粒的氧化反应。总结了沉淀法、表面反应包覆法、高分子吸附聚合法、气相包覆法和机械球磨法等多种硼颗粒包覆工艺的研究状况,分析并比较了不同工艺的作用机理和实际应用效果。介绍了现代硼颗粒表面包覆效果测试技术的特点和应用范围。评述了目前硼颗粒包覆技术的研究现状和不足,并对未来的研究方向进行了展望。