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.     

预控破片形成及侵靶行为数值模拟

为了优化预控破片弹的弹体预制槽加工方案,增强弹丸杀伤威力,提高弹体材料利用率,运用有限元软件ANSYS模拟了局部弹体材料爆轰形成预控破片的过程,研究了预控破片分别以不同初速度和不同侵彻角侵彻三种靶板的行为,并对模型应力分布和破片速度衰减变化进行了对比分析.结果表明,预制槽附近首先发生破碎,形成了形状规则的预控破片,破片的初速度、靶板材料和侵彻角都将显著影响预控破片的侵彻能力.模拟结果可为预控破片弹的设计和优化提供参考.     

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%).     

Development of open-cathode polymer electrolyte fuel cells using printed circuit board flow-field plates: Flow geometry characterisation

Open-cathode air-breathing fuel cells have the advantage of reduced system complexity and simplified operation, as oxygen is taken directly from ambient air without the need for blowers/compressors. In this study, printed circuit boards (PCBs) are used as flow-field plates. The use of PCBs offers the potential for significant cost reduction due to their well-established manufacturing processing and low materials cost. This study investigates the effect of varying the cathode geometry (parallel and circular) and opening ratios (43%, 53% and 63%) on fuel cell performance using polarisation curves, electrochemical impedance spectroscopy (EIS) and thermal imaging. The results obtained indicate that circular openings afford lower Ohmic resistance than parallel flow-field designs, which helps improve contact between the gas diffusion layer and flow-field plate. However, flow-field plates with circular openings suffer from greater mass transport limitation effects. Likewise, greater opening ratios offer better mass transport but increased Ohmic resistance as a result of the reduced area of lands/ribs. The thermal imaging results reveal lower temperature in the middle of the fuel cell due to “bowing” of the printed circuit board flow field plates which reduces the local current density. A trade-off between these factors results in a design with a maximum area specific power density of 250 mW cm⁻².     

卫生间硅酸钙板轻质隔墙上瓷砖饰面系统应用技术研究

对卫生间硅酸钙板轻质隔墙上采用瓷砖饰面系统进行了相关应用性研究，讨论了硅酸钙板厚度、界面处理、防水处理以及粘贴材料等对系统粘结力的影响，提出了在硅酸钙板轻质墙体上进行瓷砖饰面的可靠施工方案。