Paste Residence Time in a Spouted Bed Dryer. II: Effect of Spout Operational Conditions

Residence time distributions for an aqueous solution of 10% sodium chloride in a spouted bed dryer of inert particles were determined using the stimulus-response technique. Glass and polyethylene beads with diameters 2.6 and 3.4 mm were used as inert bodies in a cylindrical column of 14.0 cm diameter and 60° conical base. The effects of inert bodies load, air, and paste flow rates on the mean residence times and RTD were determined following 2³ factorial designs. The RTD could be correlated to the perfect mixing cell model with R² varying from 0.8684 to 0.9815. The mean residence times in CSBD varied from 10.8 to 13.9 and 10.7 to 13.3 min for glass and polyethylene beads, respectively. For both inert particles, mean residence times increased with bed height and decreased with paste feed rates. Also, terms of interaction among the factors were significant in some cases, showing a complex behavior of paste residence times. Equations obtained by response surface regression could predict mean residence times on glass and polyethylene beads with deviations lower than ±10%.     

Paste extrusion of polytetrafluoroethylene (PTFE): Surface tension and viscosity effects

The effects of the lubricant physical properties on the processing of polytetrafluoroethylene (PTFE) fine powder resins are studied. Lubricants having different surface tension and viscosity were used; the two properties changed independently. These effects were studied by using dies of various contraction angle and reduction ratio for resins having a variety of molecular architecture. It was found that the wettability (surface tension) of the lubricant strongly affects the pressure needed to extrude the PTFE pastes. The viscosity of the lubricant was also found to play a significant role in the process since a lubricant with a low viscosity causes the paste to be extruded at a lower pressure. These effects of the physical properties on the extrusion pressure influence significantly the mechanical properties of the final extrudates. The latter are functions of the degree of fibrillation, which is significantly influenced by the wettability and viscosity of lubricants. Finally, the effects of die geometry on extrusion pressure and mechanical properties of extrudates were also assessed in order to determine the geometrical characteristics and operation conditions for the optimization of the process.     

神经网络在膏体充填质量模型中的应用

煤矿膏体充填质量受多因素影响,且具有非线性特性,用数理统计的方法直接建立充填质量模型很困难。为了减少试验次数、降低试验费用,通过神经网络建立的膏体材料充填质量模型明显优于传统的回归分析法,利用膏体充填材料塌落度与主要影响因素浓度、胶结料用量、细集料用量的关系模型,可以有效预测膏体充填材料的塌落度。     

基于ANSYS FLUENT的超深井长距离膏体充填管道输送模拟研究

为研究超深井长距离膏体充填管道自流输送问题,根据云南某矿山实际充填管路采用Gambit建立三维数值模型,用ANSYS FLUENT软件进行数值模拟计算,以水平管道和弯管为例研究了不同配比、浓度和流量下的管道压力、流速变化规律和管道阻力损失之间的关系。通过井下工业环管的压力监测系统,统计分析矿山井下实际管道压力监测值,井下实际监测结果和采用ANSYS FLUENT软件三维数值模拟研究结果较为接近,表明ANSYS FLUENT软件模拟超深井长距离膏体充填管道输送是可行的,研究结果可为矿山实现超深井、长距离、大倍线条件下膏体充填管道输送提供技术支持。     

固相分散萃取-高效液相色谱法测定郫县豆瓣中四种苏丹红染料的研究

建立了郫县豆瓣中苏丹红Ⅰ～Ⅳ的固相分散萃取(SPDE)-高效液相色谱(HPLC)分析方法。样品用无水硫酸钠作为分散剂,以乙腈提取样品中的苏丹红,提取液用中性氧化铝层析柱进行净化。用Inertsil ODS-sp C18柱(4.6mm×250mm,5μm))分离,流动相A为乙腈,流动相B为0.1%甲酸水溶液(A∶B为90∶10,V/V),等度洗脱,流速1mL/min,柱温40℃。二极管阵列检测器检测,检测波长为517nm,利用保留时间和光谱图定性,外标法定量。4种苏丹红染料在0.10～20.00μg/mL范围内线性关系良好,相关系数均大于0.9999,苏丹红Ⅰ～Ⅳ的检出限(LOD)分别为0.009～0.013mg/kg(信噪比S/N=3)。在添加浓度为0.5～10.0mg/kg范围内平均回收率达81.67%～93.28%,相对标准偏差(RSD)为1.07%～4.61%(n=6)。     

黑小麦的加工品质性状研究

采用国际(ICC、AACC)、国家(GB)标准分析方法，以高优503为对照，通过对黑小麦1号、2号、3号(编号)品种籽粒品质、蛋白质品质、磨粉品质、面团流变学特性等小麦品种品质及食品制作品质进行系统分析。认为：黑小麦制作的面包品质较好，也可用于制作面条，制作馒头品质较差，其蛋白质品质、粉质参数、拉伸参数、粘度参数均优于普通小麦，降落数值偏高。     

The influence of filler on the emission properties and rheology of carbon nanotube paste

CNT paste consists of organic solution, inorganic binder and filler. Organic solution contains organic resins and solvent including surfactants which finely disperse CNTs. Filler affects surface morphology, electron emission property, viscosity, and rheological characteristics of CNT paste. We used different fillers such as silver and alumina in CNT paste for special function. The emission properties of CNT paste with silver are similar to those of CNT paste with alumina if filler portion is the same. From the scanning electron microscope (SEM) different morphologies of CNTs was observed depending on the type of filler. CNT paste which showed good emission property had vertically well-aligned CNTs on the surface after surface treatment using adhesive tape. We measured viscosity and rheological properties with rheometer RS600 from HAAKE. Emission property of CNT paste was evaluated in vacuum chamber of 10^{− 6} Torr with pulse generator and duty was 1/500.     

多层陶瓷电容器可镀银端头浆料

对（１）Ａｇ粉、Ａｇ２Ｏ、片状Ａｇ粉和主晶盯为ＰｂＺｎＳｉＯ４的玻璃－－陶瓷粉及（２）Ａｇ粉、片状Ａｇ粉，ＣｕＯ和ＣｄＯ固体混合料都用聚乙烯醇缩丁醛－树脂－松油醇有机体系配制成两种可镀Ａｇ端头浆料。烧结温度分别为７８０℃和８７０℃，端电极外观好，无尖峰、沟槽、针孔等缺陷。电镀的片式ＭＬＣ的性能达到ＧＢ、ＩＥＣ有关标准的技术条件。     

膏体充填管道输送阻力损失计算方法

针对云南会泽铅锌矿膏体充填,进行了充填料浆流变特性研究,并对其流变参数与浓度的关系进行了分析,建立了两者间的数学关系式,进而建立了会泽铅锌矿膏体充填料浆管道输送阻力损失计算的经验公式。经生产验证,该公式具有较好的实用性。     

硅太阳能电池的丝网印刷技术

简要介绍太阳能电池的生产工艺。针对背银、背铝、正银三工序的印刷工艺要求从刮刀、丝网、浆料、设备及基片5方面进行分析。